Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Status of the Claims
Claims 1, 4-7, 14-15, 17, and 19-21 are pending and rejected. Claims 3, 8, 10-13, 16, 18, and 23-26 are withdrawn. Claims 2, 9, and 22 are cancelled.
Claim Rejections - 35 USC § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
Claims 1, 5, 7, and 14 are rejected under 35 U.S.C. 103 as being unpatentable over Lei, US 2016/0122869 A1 in view of Nakata, US 2015/0294975 A1 and McSwiney, US 2005/0025885 A1.
Regarding claim 1, Lei teaches a method for forming a silicon nitride via a plasma enhanced ALD process (a method of forming a silicon nitride film, 0055), the method comprising:
a) providing a substrate in a reactor (0055);
b) introducing into the reactor a silicon precursor compound (introducing into the reactor a precursor of formula A
PNG
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163
275
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Greyscale
where X1 and X2 are selected from a halide atom and R3-R5 are selected from a hydrogen atom and a methyl group, 0055, where examples of Formula A include 1,5-dichloro-1,5-disilahexane, 0012 and 0031, indicating that chlorine is a suitable halide for the precursors);
c) purging the reactor of any unreacted silicon precursors and/or any reaction by-products using inert gas (purging the reactor with a purge gas, which is indicated as being an inert gas, 0038 and 0055);
d) providing a plasma comprising an ammonia source into the reactor to react with the precursor to form a silicon nitride film that is optionally carbon-doped (providing a plasma containing source into the reactor to at least partially react with the at least one organosilicon precursor compound and deposit the silicon-containing film onto the substrate, 0055); and
e) purging the reactor of any further reaction by-products from step d using inert gas (purging the reactor with a purge gas that is indicated as being an inert gas, 0038 and 0055);
wherein the steps b through e are repeated until a desired thickness of the silicon nitride film is deposited (0056); and wherein the reactor is maintained at one or more temperatures ranging from about 25°C to 600°C (where the reactor is heated to one or more temperatures ranging from ambient to about 700°C, 0055, or in the range of 100-650°C, claims 1-3, such that the temperature will overlap or be within the claimed range). According to MPEP 2131.03, “[W]hen, as by a recitation of ranges or otherwise, a claim covers several compositions, the claim is ‘anticipated’ if one of them is in the prior art.” Titanium Metals Corp.v. Banner, 778 F.2d 775, 227 USPQ 773 (Fed. Cir. 1985) (citing In re Petering, 301 F.2d 676, 682, 133 USPQ 275, 280 (CCPA 1962)) (emphasis in original). According to MPEP 2144.05, “in the case where the claimed ranges “overlap or lie inside ranges disclosed by the prior art” a prima facie case of obviousness exists.” In re Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976).
They teach that the process for forming the silicon-based film is by PEALD (0007 and 0010). They teach that ALD refers to a self-limiting (e.g., the amount of film material deposited in each reaction cycle is constant), sequential surface chemistry that deposits film of materials onto substrates of varying compositions (0035). They teach that in ALD, film growth proceeds by self-limiting control of surface reaction (0036). They teach that in PEALD, a substrate, such as a silicon oxide substrate, is exposed to the precursor initially to allow the complex to chemically adsorb on to the surface of the substrate (0044). Since they teach that material is deposited in each reaction cycle and that in PEALD the precursors chemically adsorb to the surface of the substrate, the precursor of Formula A is considered to be chemisorbed (chemically absorbed) on the substrate during step b.
They teach that an example of the silicon containing film that is formed using the organosilicon precursors and methods described has the formulation SixCyNz where C ranges from about 0% to about 50% by atomic weight percent (0062), such that the carbon concentration overlaps the claimed range. According to MPEP 2144.05, “in the case where the claimed ranges “overlap or lie inside ranges disclosed by the prior art” a prima facie case of obviousness exists.” In re Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976).
Further, they teach that the atomic weight percent of carbon and nitrogen in the silicon-based films can be tuned by changing deposition conditions such as temperature, adding a nitrogen source, or a combination thereof (0006). Therefore, when forming a silicon nitride film, it would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to have optimized the deposition conditions to minimize the carbon concentration in the film so as to be within the claimed range with the expectation of forming a silicon nitride film as opposed to a carbon-doped silicon nitride film. According to MPEP 2144.05 II A, “Generally, differences in concentration or temperature will not support the patentability of subject matter encompassed by the prior art unless there is evidence indicating such concentration or temperature is critical. “[W]here the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation.” In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955).
They do not teach that the substrate comprises a surface feature.
Nakata teaches forming a barrier insulating film at an interface between and insulating film and a buried wiring line in a trench for use in a semiconductor device (abstract). They teach using a silicon oxide film as a first insulating film 11A (0072 and Fig. 1C). They teach using barrier insulating film 11B disposed on the surface of the first insulating layer, where the barrier insulating film 11B can be formed using a single-layer film or a laminated film comprising SiN, SiON, etc. (0073 and Fig. 1C). They teach forming the barrier insulating film 11B by PEALD when a SiN film or a SiON film is desired (0143-0146).
From the teachings of Nakata, it would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to have modified the process of Lei to have deposited the SiN film in a trench as a barrier layer 11B as in the process of Nakata because Nakata teaches that SiN films are desirably deposited in such surface features for use as barrier layers such that it will be expected to provide a desirable application for the SiN film of Lei. Therefore, in the process of Lei in view of Nakata, a substrate comprising a surface feature (i.e., a trench) will be provided to the reactor for forming the SiN film in the trench as a barrier layer. Further, since Lei indicates that the precursors chemically adsorb to the substrate in PEALD, where they provide an example of a silicon oxide substrate and the first insulating film 11A is silicon oxide, where Nakata teaches forming the films by PEALD, the precursor is also expected to chemisorb to the silicon oxide insulating film in depositing the SiN film by PEALD.
Lei teaches using precursors comprising two Si atoms, at least one Si-Me group, and an ethylene or propylene linkage between the Si atoms (abstract).
They do not teach one of the listed precursors.
McSwiney teaches a method of combining a silicon source precursor and a nitrogen source precursor at a temperature up to 550°C for forming a silicon nitride film (abstract). They teach that suitable nitrogen sources include ammonia as well as more reactive nitrogen sources (0018). They teach that suitable silicon sources include silyl hydrocarbons (0019). They teach that precursors include silicon atoms bridged by hydrocarbon fragments (0043). They teach that examples include 1,2-bis(trichlorosilyl)ethane (i.e., 1,1,1,4,4,4,-hexachloro-1,4-disilabutane) and 1,2-bis(dichloro(methyl)silyl)ethane (i.e., 2,2,5,5,-tetrachloro-2,5-disilahexane) (0050 and Fig. 8). They teach that the precursors facilitate a lower silicon nitride formation temperature and include increased bond strain and increased functional group reactivity (0052).
From the teachings of McSwiney, it would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to have modified the process of Lei in view of Nakata to have used 1,1,1,4,4,4,-hexachloro-1,4-disilabutane or 2,2,5,5,-tetrachloro-2,5-disilahexane as the silicon precursor for forming the SiN film because McSwiney teaches that such precursors facilitate a lower silicon nitride formation temperature and include increased bond strain and increased functional group reactivity, where they are similar to the precursors of Lei, i.e., having an ethylene linkage between two Si atoms and including halogen reactive groups, where 2,2,5,5,-tetrachloro-2,5-disilahexane also includes two Si-Me groups such that the substitution is expected to provide the desirable result of successfully forming the SiN film at lower temperatures and chemisorbing to the substrate.
Regarding claim 5, Lei in view of Nakata and McSwiney suggest the process of claim 1. Lei further teaches that the silicon-containing films are exposed to a post-deposition treatment such as ultraviolet light exposure (0062), such that the film will be exposed to a UV light source after deposition.
Regarding claim 7, Lei in view of Nakata and McSwiney suggest the process of claim 1. Nakata further teaches when forming a SiON barrier layer, they provide a SiN film and then expose the film to ozone as an oxidizing gas so as to oxidize the SiN film to form SiON (0148). They teach that all steps of the process are implemented at a temperature in a range of between 450 and 550°C (0147). They teach repeating the steps of forming the SiN film and oxidizing it 6 times (0147). From this, it would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to have modified the process of Lei in view of Nakata and McSwiney to have also exposed the SiN film to ozone, i.e., an oxygen source, at a temperature in the range of 450-550°C for forming an SiON barrier layer because Nakata teaches that such process provides a desirable barrier layer by oxidizing SiN to SiON. Further, Nakata teaches performing the oxidation step in the same chamber as deposition (0148), such that it would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to have converted the SiN film to the SiON film in situ because Nakata indicates that both steps can be performed in the same chamber.
Regarding claim 14, Lei in view of Nakata and McSwiney suggest the process of claim 1. Lei further teaches that the silicon-containing films are exposed to a post-deposition treatment such as a thermal anneal at one or more temperatures ranging from about 500 to about 1000°C (0062), such that a thermal anneal will be performed on the SiN film at a temperature within the claimed range. According to MPEP 2131.03, “[W]hen, as by a recitation of ranges or otherwise, a claim covers several compositions, the claim is ‘anticipated’ if one of them is in the prior art.” Titanium Metals Corp.v. Banner, 778 F.2d 775, 227 USPQ 773 (Fed. Cir. 1985) (citing In re Petering, 301 F.2d 676, 682, 133 USPQ 275, 280 (CCPA 1962)) (emphasis in original).
Claim 4 is rejected under 35 U.S.C. 103 as being unpatentable over Lei in view of Nakata and McSwiney as applied to claim 7 above, and further in view of Cheng, US 2018/0350668 A1.
Regarding claim 4, Lei in view of Nakata and McSwiney suggest the process of claim 1. As discussed above for claim 14, Lei teaches performing a thermal anneal on the silicon-containing films at a temperature in the range from about 500 to about 1000°C (0062).
They do not teach spike annealing.
Cheng teaches depositing a first film in a feature so that the first film forms on the bottom of the feature and on the side walls of the feature near the substrate (0007). They teach that the first film is etched from the sidewalls and the film at the bottom is treated to form a second film in the feature (0007). They teach that the second film comprises one or more of SiN or SiON (0008). They teach that the first film comprises silicon (0022). They teach depositing the first film on the substrate comprises exposing the substrate to a silicon precursor and a reactant (0023). They teach that the reactant comprises one or more of Ar, He, H2, or N2, where the reactant can include plasma (0025-0027). They teach treating the first film to form a second film comprising silicon nitride (0040). They teach providing a post-processing process to improve some parameter of the film or substrate, where post-processing comprises annealing the film (0046). They teach that annealing can be done by rapid thermal anneal, spike anneal, or UV cure, where the annealing temperature is in the range of about 500°C to 900°C (0046).
From the teachings of Lei and Cheng, it would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to have performed a spike anneal treatment on the SiN film at a temperature in the range of 500-1000°C (i.e., the annealing temperature taught by Lei) because Lei teaches that it is desirable to anneal at such a temperature range and Cheng teaches that spike annealing at a range within the range of Lei can improve film properties, where the film is formed from materials including SiN such that it will be expected to provide a suitable annealing process for improving the SiN film properties. Therefore, the spike annealing will be done at a temperature within the claimed range. According to MPEP 2131.03, “[W]hen, as by a recitation of ranges or otherwise, a claim covers several compositions, the claim is ‘anticipated’ if one of them is in the prior art.” Titanium Metals Corp.v. Banner, 778 F.2d 775, 227 USPQ 773 (Fed. Cir. 1985) (citing In re Petering, 301 F.2d 676, 682, 133 USPQ 275, 280 (CCPA 1962)) (emphasis in original).
Claim 17 is rejected under 35 U.S.C. 103 as being unpatentable over Lei in view of Nakata and McSwiney as applied to claim 7 above, and further in view of Jung, US 2005/0233598 A1.
Regarding claim 17, Lei in view of Nakata and McSwiney suggest the process of claim 7.
They do not teach performing a plasma treatment on the SiON film.
Jung teaches forming a stack including a first dielectric layer and a second dielectric layer by ALD with a post-treatment step performed to the stacked layers (abstract). They teach that the dielectric layer may be formed of SiON (0013). They teach that the post-treatment of the stacked dielectric layer is performed to remove impurities in the stacked dielectric layer (0015). They teach that the post-treatment is performed by a heat-treatment in a substantially inert atmosphere, heat-treatment in a hydrogen atmosphere, plasma treatment in a hydrogen atmosphere or any combination of two or more of these carried out simultaneously or in any suitable order (0016). They teach performing heat treatments at 150°C (0044), 450°C, 500°C, 600°C, 700°C, and 750°C (Table 1). From this, it would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to have optimized the heat treatment in the range of 150-750°C because Jung teaches that such temperatures are used for performing heat treatments, suggesting that such a range will provide suitable heating.
From the teachings of Jung, it would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to have modified the process of Lei in view of Nakata and McSwiney to have performed a hydrogen plasma treatment on the SiON film at a temperature optimized to be within the claimed range from the overlapping temperature range suggested by Jung because Jung teaches that hydrogen heat-treatment and hydrogen plasma treatments reduce impurities in SiON, where the treatments can be performed simultaneously such that it will be expected to reduce any impurities in the SiON film. Therefore, the SiON film will be treated with a hydrogen plasma at a temperature optimized to be within the claimed range from the overlapping range suggested by Jung. According to MPEP 2144.05, “in the case where the claimed ranges “overlap or lie inside ranges disclosed by the prior art” a prima facie case of obviousness exists.” In re Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976). According to MPEP 2144.05 II A, “Generally, differences in concentration or temperature will not support the patentability of subject matter encompassed by the prior art unless there is evidence indicating such concentration or temperature is critical. “[W]here the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation.” In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955).
Claims 1, 6, 15, 19, and 20 are rejected under 35 U.S.C. 103 as being unpatentable over Lei, US 2016/0122869 A1 in view of Chen, US 2017/0372886 A1 and McSwiney, US 2005/0025885 A1.
Regarding claims 1, 19, and 20, as discussed above for claim 1, Lei teaches a method for forming a silicon nitride via a PEALD process by (a) providing a substrate in a reactor, (b) introducing a silicon precursor, where it is understood to chemisorb to the substrate surface to form a chemisorbed layer, (c) purging the reactor of any unreacted silicon precursors and/or any reaction by-products using an inert gas, (d) providing a plasma source into the reactor to react with the chemisorbed layer to form a silicon nitride film, where the plasma source is ammonia, and (e) purging the reactor of any reaction by-products with an inert gas, where the film has a carbon concentration overlapping the claimed range or optimized to be within the claimed range.
Lei does not teach that the substrate has a feature or using a first and second plasma.
Chen teaches methods for forming silicon nitride films by PEALD (abstract). They teach forming a thin film on a substrate in a reaction space by contacting the substrate with a first silicon halide to provide a first silicon species adsorbed on a surface of the substrate, and contacting the substrate comprising the first species adsorbed on the surface with a first plasma step to deposit a material on the substrate and then conducting a nitrogen plasma treatment (0016). They teach that the nitrogen plasma treatment includes contacting the substrate comprising the material on the surface with a second plasma formed from a nitrogen containing gas substantially free of hydrogen-containing species to form the thin silicon nitride film (0016). They teach that the silicon nitride on the substrate can be contacted with the second plasma after every silicon nitride deposition cycle (0017). They teach that the PEALD process is performed at temperatures ranging from about 25°C to about 700°C (0098), i.e., a range at least overlapping the range of Lei. They teach that suitable nitrogen precursors for the second reactant comprise plasma formed from ammonia (0120). They teach forming the silicon nitride thin film by PEALD on a substrate having three-dimensional features, such as in FinFET application (0130). They teach that the process includes (1) providing a substrate comprising a three-dimensional structure in a reaction space, (2) introducing a silicon-containing precursor into the reaction space so that silicon-containing species are adsorbed to a surface of the substrate, (3) removing excess silicon-containing precursor and reaction byproducts from the reaction space, (4) introducing a nitrogen containing precursor such as ammonia into the reaction space, (5) generating reactive species from the nitrogen precursor, (6) contacting the substrate with the reactive species, and (7) removing excess nitrogen atoms, plasma, or radicals and reaction byproducts (0130-0137). They teach that steps (2) through (7) may be repeated until a silicon nitride of a desired thickness is formed (0138). They teach using plasma treatment steps to enhance film properties, in particular for plasma densification using nitrogen plasma (0254). They teach forming the SiN film by PEALD and then performing a second plasma treatment step after each PEALD cycle, where the second plasma is a nitrogen plasma (0255). They teach that the second plasma step may lead to densification of the deposited SiN film or otherwise improve the film properties (0255). They teach that the second plasma treatment step does not include hydrogen species (0255). They teach that utilizing the nitrogen plasma treatment may facilitate formation of silicon nitride films having certain desired characteristics while reducing or avoiding formation of defects such as silicon nitride film delamination and/or formation of blister defects in the silicon nitride film (0256). They teach that the SiN film is formed by (1) introducing a silicon-containing precursor into the reaction space so that silicon-containing species are adsorbed to a surface of the substrate, (2) removing excess silicon-containing precursor and reaction byproducts from the reaction space, (3) introducing a nitrogen containing precursor such as ammonia into the reaction space, (4) generating reactive species from the nitrogen precursor, (5) contacting the substrate with the reactive species, (6) removing excess nitrogen atoms, plasma, or radicals and reaction byproducts, (7) applying to the substrate a nitrogen plasma treatment, where steps (1) through (6) may be repeated until a silicon nitride film of a desired thickness is formed (0263-0271). They teach that the process may be performed at a temperature between about 200°C to about 400°C (0277). While they do not teach removing excess reaction by-products after the second plasma before repeating the process, since they indicate it is desirable to purge the reactor after the first plasma before repeating the process (0137-0138), they teach purging between the plasma steps (0263-0271), and they teach that nitrogen can be a reactant with the silicon precursor (0266), it would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to have also purged the reactor of excess nitrogen, plasma, or radicals and/or reaction byproducts if any after the nitrogen plasma treatment and before repeating the deposition process because it will prevent any gas phase reactions between the silicon precursor and plasma present in the reactor and prevent any contamination resulting from any reaction by-products so as to ensure a high quality film.
From the teachings of Chen, it would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to have modified the process of Lei to have deposited the films on a substrate having three-dimensional features such as in FinFET applications and to have performed the nitrogen plasma treatment after each cycle of SiN deposition because Chen teaches that SiN films are desirably deposited on 3D substrate features for FinFET application and that a nitrogen plasma treatment after each cycle of SiN deposition by PEALD with an ammonia plasma reactant improves the SiN film quality. Therefore, in the process of Lei in view of Chen, the process of forming the SiN film by PEALD will include providing a substrate comprising a feature into a reactor, introducing a silicon precursor so as to chemisorb onto the substrate, purging the reactor, providing a first plasma comprising ammonia to the reactor to react with the chemisorbed layer to form a SiN film, purging the reactor, providing a second plasma comprising nitrogen that will react with the film to densify it so as to further form a densified SiN, purging the reactor, and repeating the process until a desired thickness of the film is deposited. Further, since Lei teaches performing PEALD at a range from ambient to 700°C and Chen teaches performing the PEALD process from 25°C to 700°C or from 200-400°C, it would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to have optimized the temperature to be within the claimed range from the ranges overlapping or within the claimed range provided by Lei and Chen so as to provide a desirable temperature for the process. According to MPEP 2131.03, “[W]hen, as by a recitation of ranges or otherwise, a claim covers several compositions, the claim is ‘anticipated’ if one of them is in the prior art.” Titanium Metals Corp.v. Banner, 778 F.2d 775, 227 USPQ 773 (Fed. Cir. 1985) (citing In re Petering, 301 F.2d 676, 682, 133 USPQ 275, 280 (CCPA 1962)) (emphasis in original). According to MPEP 2144.05, “in the case where the claimed ranges “overlap or lie inside ranges disclosed by the prior art” a prima facie case of obviousness exists.” In re Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976). According to MPEP 2144.05 II A, “Generally, differences in concentration or temperature will not support the patentability of subject matter encompassed by the prior art unless there is evidence indicating such concentration or temperature is critical. “[W]here the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation.” In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955).
While Lei in view of Chen do not teach that that ammonia plasma further reacts with the chemisorbed layer to form the SiN film, since they provide an ammonia first plasma and a nitrogen second plasma as required by claims 19 and 20, the process is also expected to result in the ammonia plasma further reacting with the chemisorbed layer to form the SiN film. According to MPEP 2112.01 I, “Where the claimed and prior art products are identical or substantially identical in structure or composition, or are produced by identical or substantially identical processes, a prima facie case of either anticipation or obviousness has been established. In re Best, 562 F.2d 1252, 1255, 195 USPQ 430, 433 (CCPA 1977)”.
They do not teach using one of the listed precursors.
As discussed above, from the teachings of McSwiney, it would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to have modified the process of Lei in view of Chen to have used 1,1,1,4,4,4,-hexachloro-1,4-disilabutane or 2,2,5,5,-tetrachloro-2,5-disilahexane as the silicon precursor for forming the SiN film because McSwiney teaches that such precursors facilitate a lower silicon nitride formation temperature and include increased bond strain and increased functional group reactivity, where they are similar to the precursors of Lei, i.e., having an ethylene linkage between two Si atoms and including halogen reactive groups, where 2,2,5,5,-tetrachloro-2,5-disilahexane also includes two Si-Me groups such that the substitution is expected to provide the desirable result of successfully forming the SiN film at lower temperatures and chemisorbing to the substrate.
Regarding claims 6 and 15, Lei in view of Chen and McSwiney suggest the process of claims 1 and 19, where, as discussed above, the SiN film will be exposed to a nitrogen plasma as a second plasma, where the temperature of the process is optimized to be within the claimed range.
Claims 1, 6, 15, 19, and 21 are rejected under 35 U.S.C. 103 as being unpatentable over Lei, US 2016/0122869 A1 in view of Li, US 2017/0263438 A1 and McSwiney, US 2005/0025885 A1.
Regarding claims 1, 19, and 21, as discussed above for claims 1 and 19, Lei teaches a method for forming a silicon nitride via a PEALD process by (a) providing a substrate in a reactor, (b) introducing a silicon precursor, where it is understood to chemisorb to the substrate surface to form a chemisorbed layer, (c) purging the reactor of any unreacted silicon precursors and/or any reaction by-products using an inert gas, (d) providing a plasma source into the reactor to react with the chemisorbed layer to form a silicon nitride film, where the plasma source is ammonia, and (e) purging the reactor of any reaction by-products with an inert gas, where the film has a carbon concentration overlapping the claimed range or optimized to be within the claimed range. Lei further teaches that the plasma source in step (d) can be nitrogen plasma as an alternative to ammonia (0057).
Lei does not teach that the substrate has a feature or using a first and second plasma.
Li teaches methods for forming a spacer comprising depositing a film on the top, bottom, and sidewalls of a feature and treating the film to change a property of the film on the top and bottom of the feature (abstract). They teach selectively dry etching the film from the top and bottom of the feature relative to the film on the sidewalls of the feature using a high intensity plasma (abstract). They teach that the substrate surface is exposed to a deposition environment comprising at least one deposition cycle comprising sequential exposure to a silicon precursor and a nitrogen containing reactant to form a silicon nitride film on the top, bottom, and sidewalls of the at least one feature (0007). They teach that the silicon nitride film is exposed to a treatment environment to modify the silicon nitride film deposited on the top and bottom of the at least one feature, where the treatment environment comprises a plasma (0007). They teach that the modified silicon nitride film is dry etched using a plasma (0007). They teach forming the film by ALD and then exposing it to in-situ post treatment after every cycle (0024). They teach that formation and treatment of the film can be repeated until a film with a predetermined total thickness has been formed (0044). They teach that SiN film is formed on the 3D structures in forming a spacer for depositing selective spacer films (0005 and 0025). They teach forming the SiN film by PEALD using a silicon precursor and a nitrogen reactant to form the SiN film (0032, 0034, and 0036). They teach that suitable nitrogen reactants include nitrogen plasma (0036). They teach that the plasma used in the treatment can be any suitable plasma capable of modifying the film properties, where the plasma includes ammonia (0042-0043 and 0059). They teach that the silicon and nitrogen precursor form a conformal SiN film and the plasma treatment modifies the film on the top and bottom of the feature, where the process is done at temperatures in the range of about 200°C to about 550°C (0027). They teach that the plasma treatment generates etch rate selectivity/difference between the trench top vs. sidewall vs. bottom for forming the spacers (abstract, 0025, 0046, and 0048). They teach exposing the substrate to the silicon precursor, exposing it to a purge gas, i.e., gas curtain, and exposing the substrate to a N2/Ar plasma for forming the film (0077-0078, 0086-0088 and Fig. 4-5). They teach that once a layer of predetermined thickness has been formed, the substrate can be exposed to a treatment environment for an ammonia plasma treatment (0090 and Fig. 4-5). They teach that each processing section is separated by a gas curtain or purge gas port (0079 and Fig. 5). Therefore, since each processing environment is separated by a purge port, the substrate will be exposed to a purge gas after the silicon precursor exposure, after the N2 plasma reactant for forming the SiN film, and after the ammonia plasma treatment before repeating the process.
From the teachings of Li, it would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to have modified the process of Lei to have deposited the SiN film on 3D features for forming spacers as in the method of Li so as to expose the substrate to the precursor of Lei, purged the reactor with an inert gas, exposed the substrate to a N2 plasma reactant for forming the SiN film, purged the reactor, exposed the substrate to an ammonia plasma for modifying and further forming the SiN film with different etch selectivities, and then to have purged the reactor before repeating the process because Li teaches that such a process is desirable for forming selective spacer films such that it will be expected to provide a desirable method for forming SiN spacer films. Further, since Lei teaches performing the process at temperatures from ambient to 700°C and Li teaches performing the process at a temperature of 200-500°C, it would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to have optimize the temperature to be within the claimed range from ranges of Lei and Li so as to have provided a desirable temperature for the deposition and treatment processes. According to MPEP 2131.03, “[W]hen, as by a recitation of ranges or otherwise, a claim covers several compositions, the claim is ‘anticipated’ if one of them is in the prior art.” Titanium Metals Corp.v. Banner, 778 F.2d 775, 227 USPQ 773 (Fed. Cir. 1985) (citing In re Petering, 301 F.2d 676, 682, 133 USPQ 275, 280 (CCPA 1962)) (emphasis in original). According to MPEP 2144.05, “in the case where the claimed ranges “overlap or lie inside ranges disclosed by the prior art” a prima facie case of obviousness exists.” In re Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976). According to MPEP 2144.05 II A, “Generally, differences in concentration or temperature will not support the patentability of subject matter encompassed by the prior art unless there is evidence indicating such concentration or temperature is critical. “[W]here the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation.” In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955).
While Lei in view of Li do not teach that that ammonia plasma further reacts with the chemisorbed layer to form the SiN film, since they provide a N2 first plasma and an ammonia second plasma as required by claims 19 and 21, the process is also expected to result in the ammonia plasma further reacting with the chemisorbed layer to form the SiN film. According to MPEP 2112.01 I, “Where the claimed and prior art products are identical or substantially identical in structure or composition, or are produced by identical or substantially identical processes, a prima facie case of either anticipation or obviousness has been established. In re Best, 562 F.2d 1252, 1255, 195 USPQ 430, 433 (CCPA 1977)”.
As discussed above, from the teachings of McSwiney, it would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to have modified the process of Lei in view of Li to have used 1,1,1,4,4,4,-hexachloro-1,4-disilabutane or 2,2,5,5,-tetrachloro-2,5-disilahexane as the silicon precursor for forming the SiN film because McSwiney teaches that such precursors facilitate a lower silicon nitride formation temperature and include increased bond strain and increased functional group reactivity, where they are similar to the precursors of Lei, i.e., having an ethylene linkage between two Si atoms and including halogen reactive groups, where 2,2,5,5,-tetrachloro-2,5-disilahexane also includes two Si-Me groups such that the substitution is expected to provide the desirable result of successfully forming the SiN film at lower temperatures and chemisorbing to the substrate.
Regarding claim 6, Lei in view of Li and McSwiney suggest the process of claims 1 and 19. Li further teaches that the treatment plasma includes argon or helium (0042-0043), such that the SiN film will be exposed to a plasma comprising an inert gas along with ammonia.
Regarding claim 15, Lei in view of Li and McSwiney suggest the process of claims 1 and 19. Li further teaches that the treatment plasma includes one or more of argon, nitrogen, or helium (0042-0043). Therefore, it would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to have alternatively provided an inert gas or nitrogen as the second plasma as a substitution for ammonia. Further, as noted above for claim 19, the temperature is suggested to be optimized to be within the claimed range.
Claims 1 and 5 are rejected under 35 U.S.C. 103 as being unpatentable over Nguyen, US 2014/0273529 A1.
Regarding claim 1, Nguyen teaches a method for forming a silicon nitride or carbon-doped silicon nitride via a plasma enhanced ALD process (abstract), the method comprising:
a) providing a substrate comprising a surface feature in a reactor (where deposition is done in a chamber on a substrate, abstract, 0036, 0038, 0056, and 0059, indicating that a substrate will be provided to a reactor or chamber, where the substrate has structures in dense 7:1 AR with a gap of 60 nm, 0065, indicating that the substrate will comprise a surface feature);
b) introducing into the reactor a silicon precursor compound selected from the group consisting of 1,1,1,4,4,4-hexachloro-1,4- disilabutane, 1,1,1,4,4,4-hexachloro-2-methyl-1 ,4-disilabutane, 1,1,1,4,4- pentachloro-1,4-disilapentane, 1,1,1,4,4-pentachloro-2-methyl-1,4- disilapentane, 2,2,5,5-tetrachloro-2,5-disilahexane, 2,2,5,5-tetrachloro-3- methyl-2,5-disilahexane; 1,1,1,5,5,5-hexachloro-1,5-disilapentane, 2,2,6,6- tetrachloro-3-methyl-2,6-disilaheptane, 1,1,4,4-tetrachloro-1,4-disilapentane,1,1,4,4-tetrachloro-2-methyl-1,4-disilapentane, 1,1,4,4,4-pentachloro-1,4- disilabutane, 1,1,4,4,4-pentachloro-2-methyl-1,4-disilabutane, 1,4,4,4- tetrachloro-1,4-disilabutane, 1,4,4,4-tetrachloro-2-methyl-1,4-disilabutane,1,4,4-trichloro-1,4-disilapentane, 1,4,4-trichloro-2-methyl-1 ,4-disilapentane,1,1,5,5,5-pentachloro-1,5-disilapentane, 1,1,5,5,5-pentachloro-2-methyl-1 ,5- disilapentane, 1,1,5,5-tetrachloro-1,5-disilahexane, 1,1,5,5-tetrachloro-2- methyl-1,5-disilahexane, 1,5,5,5-tetrachloro-1,5-disilapentane, 1,5,5,5- tetrachloro-2-methyl-1,5-disilapentane, 1,5,5-trichloro-1,5-disilahexane, and 1,5,5-trichloro-2-methyl-2,6-disilahexane, wherein the silicon precursor reacts on at least a portion of the surface feature of the substrate to provide a chemisorbed layer (where the precursor has the formula (XyH3-ySi)(CH2)n(SiXyH3-y), where X is Cl, n is 2 or 3, and y has a value of 1 to 4, 0012 and 0029, such that it includes listed precursors such as 1,1,1,4,4,4,-hexachloro-1,4-disilabutane, where the substrate is exposed to the precursor to form a monolayer of atoms on the surface, 0033-0034, indicating that the precursor will react on a portion of the surface to provide a layer, and where the silicon precursor reacts with the surface of the substrate, 0027, such that the monolayer is understood to be chemisorbed due to the reaction with the substrate surface);
c) purging the reactor of any unreacted silicon precursors and/or any reaction by-products using inert gas (purging excess silicon precursor, 0048, where purge gases are indicated as being inert, 0058, such that unreacted silicon precursors will be purged from the reactor using an inert gas);
d) providing a plasma comprising an ammonia source into the reactor to react with the chemisorbed layer to form a silicon nitride film that is optionally carbon-doped (exposing the substrate to an ionized reducing agent, 0049, where the reducing agent is ammonia that is ionized to form a plasma, 0034 and 0041-0042); and
e) purging the reactor of any further reaction by-products from step d using inert gas (purging excess ionized reducing agent, abstract, 0011, and 0050, such that the reactor will be purged of reducing agent and any reaction by-products during the purge by using inert gas);
wherein the steps b through e are repeated until a desired thickness of the silicon nitride film is deposited (where the steps are repeated until the desired film thickness is achieved, 0047-0053); and wherein the reactor is maintained at one or more temperatures ranging from about 250C to 600C (where the temperature of the process is from about 20°C to about 550°C or about 50, 100, 200, 250, or 300°C to about 400, 450, or 500°C, 0040).
Therefore, they teach forming the silicon nitride layer at a temperature within the claimed range. According to MPEP 2131.03, “[W]hen, as by a recitation of ranges or otherwise, a claim covers several compositions, the claim is ‘anticipated’ if one of them is in the prior art.” Titanium Metals Corp.v. Banner, 778 F.2d 775, 227 USPQ 773 (Fed. Cir. 1985) (citing In re Petering, 301 F.2d 676, 682, 133 USPQ 275, 280 (CCPA 1962)) (emphasis in original).
They teach performing the deposition process at a pressure of about 1 torr to about 50 torr, or about 4, 5, 6, 7, 8, 9, or 10 torr (0038). They teach that the frequency of the plasma is 13.56 MHz, where the gases can be ionized within the process area so as to provide a direct plasma (0041). They teach that the plasma power is from about 1 W to about 1 kW, or about 50, 75, 200, 300, or 400 W (0042). They teach that the exposure time of the plasma per layer may range from about 1 second to about 50 seconds, in the range of about 5 or 10 seconds to about 20, 30, or 40 seconds, or about 10 seconds (0042). The instant specification at [0076] and Table 3 indicates depositing a film at 300°C using 1,1,1,4,4,4-hexachloro-1,4-disilabutane with a plasma power of 300 W, where the carbon in the film is undetectable. The instant specification at [0040] indicates that the pressure is 100 torr or less, where [0071] indicates that the pressure is in a range of about 1 to about 5 torr. The instant specification indicates that a 13.56 MHz direct plasma is used at [0070]. Therefore, Nguyen teaches depositing the film using a temperature within the claimed range, using the claimed precursors, at a pressure within or overlapping the ranges in the instant specification, using plasma powers meeting the powers used in the instant specification, and using a direct plasma having a frequency meeting that described in the instant specification. While Nguyen does not teach the amount of carbon in the film, since they provide the claimed process and use deposition parameters meeting those described in the instant specification which results in an undetectable amount of carbon, the resulting film is also expected to have a carbon content meeting the claimed range. According to MPEP 2112.01 I, “Where the claimed and prior art products are identical or substantially identical in structure or composition, or are produced by identical or substantially identical processes, a prima facie case of either anticipation or obviousness has been established. In re Best, 562 F.2d 1252, 1255, 195 USPQ 430, 433 (CCPA 1977)”.
Alternatively, Nguyen teaches that SiN refers to a film deposited that comprises Si-N linkages, where the film may be represented by the formula Si3Nx, where s is equal to about 4 (0026). They teach that the variable x may vary depending on the specific precursors chosen, including the initial ratio of silicon to carbon in the precursors (0026). From this, it would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to have optimized the film to have a carbon concentration within the claimed range because Nguyen teaches depositing SiN film as opposed to carbon-doped films or SiCN films, suggesting that carbon is not desired in the films such that it will be expected to provide a pure SiN as desired. According to MPEP 2144.05 II A, “Generally, differences in concentration or temperature will not support the patentability of subject matter encompassed by the prior art unless there is evidence indicating such concentration or temperature is critical. “[W]here the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation.” In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955).
Regarding claim 5, Nguyen suggests the process of instant claim 1. They further teach exposing the film to a UV light source after deposition (0024 and 0045).
Claim 4 is rejected under 35 U.S.C. 103 as being unpatentable over Nguyen as applied to claim 1 above, and further in view of Cheng, US 2018/0350668 A1.
Regarding claim 4, Nguyen suggest the process of claim 1. They teach performing post-deposition treatments to engineering the film properties (0043).
They do not teach spike annealing.
Cheng teaches depositing a first film in a feature so that the first film forms on the bottom of the feature and on the side walls of the feature near the substrate (0007). They teach that the first film is etched from the sidewalls and the film at the bottom is treated to form a second film in the feature (0007). They teach that the second film comprises one or more of SiN or SiON (0008). They teach that the first film comprises silicon (0022). They teach depositing the first film on the substrate comprises exposing the substrate to a silicon precursor and a reactant (0023). They teach that the reactant comprises one or more of Ar, He, H2, or N2, where the reactant can include plasma (0025-0027). They teach treating the first film to form a second film comprising silicon nitride (0040). They teach providing a post-processing process to improve some parameter of the film or substrate, where post-processing comprises annealing the film (0046). They teach that annealing can be done by rapid thermal anneal, spike anneal, or UV cure, where the annealing temperature is in the range of about 500°C to 900°C (0046).
From the teachings of Nguyen and Cheng, it would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to have performed a spike anneal treatment on the SiN film at a temperature in the range of 500-900°C because Nguyen teaches treating the films after deposition to engineer the film properties and Cheng teaches that spike annealing at about 500-900°C can improve film properties, where the film is formed from materials including SiN such that it will be expected to provide a suitable annealing process for improving the SiN film properties. Therefore, the spike annealing will be done at a temperature within the claimed range. According to MPEP 2131.03, “[W]hen, as by a recitation of ranges or otherwise, a claim covers several compositions, the claim is ‘anticipated’ if one of them is in the prior art.” Titanium Metals Corp.v. Banner, 778 F.2d 775, 227 USPQ 773 (Fed. Cir. 1985) (citing In re Petering, 301 F.2d 676, 682, 133 USPQ 275, 280 (CCPA 1962)) (emphasis in original).
Claims 6, 15, 19, and 21 is rejected under 35 U.S.C. 103 as being unpatentable over Nguyen as applied to claim 1 above, and further in view of Li, US 2017/0263438 A1.
Regarding claims 6, 19, and 21, Nguyen suggests the process of claim 1, so as to provide steps a)-e) of claim 19. They further teach after deposition, performing a plasma treatment to engineer film properties (0043). They teach exposing the SiN film to a plasma treatment once about 10 to about 40 angstroms of film have been deposited and repeating the process until the desired film thickness has been achieved (0052 and 0053). They teach that reducing agents include NH3, H2, and N2 (0034).
They do not teach that the plasma comprises hydrogen, inert gas, or nitrogen.
Li teaches methods for forming a spacer comprising depositing a film on the top, bottom, and sidewalls of a feature and treating the film to change a property of the film on the top and bottom of the feature (abstract). They teach selectively dry etching the film from the top and bottom of the feature relative to the film on the sidewalls of the feature using a high intensity plasma (abstract). They teach that the substrate surface is exposed to a deposition environment comprising at least one deposition cycle comprising sequential exposure to a silicon precursor and a nitrogen containing reactant to form a silicon nitride film on the top, bottom, and sidewalls of the at least one feature (0007). They teach that the silicon nitride film is exposed to a treatment environment to modify the silicon nitride film deposited on the top and bottom of the at least one feature, where the treatment environment comprises a plasma (0007). They teach that the modified silicon nitride film is dry etched using a plasma (0007). They teach forming the film by ALD and then exposing it to in-situ post treatment after every cycle (0024). They teach that formation and treatment of the film can be repeated until a film with a predetermined total thickness has been formed (0044). They teach that SiN film is formed on the 3D structures in forming a spacer for depositing selective spacer films (0005 and 0025). They teach forming the SiN film by PEALD using a silicon precursor and a nitrogen reactant to form the SiN film (0032, 0034, and 0036). They teach that suitable nitrogen reactants include nitrogen plasma (0036). They teach that the plasma used in the treatment can be any suitable plasma capable of modifying the film properties, where the plasma includes ammonia (0042-0043 and 0059). Li further teaches that the treatment plasma includes argon or helium (0042-0043). They teach that the silicon and nitrogen precursor form a conformal SiN film and the plasma treatment modifies the film on the top and bottom of the feature, where the process is done at temperatures in the range of about 200°C to about 550°C (0027). They teach that the plasma treatment generates etch rate selectivity/difference between the trench top vs. sidewall vs. bottom for forming the spacers (abstract, 0025, 0046, and 0048). They teach exposing the substrate to the silicon precursor, exposing it to a purge gas, i.e., gas curtain, and exposing the substrate to a N2/Ar plasma for forming the film (0077-0078, 0086-0088 and Fig. 4-5). They teach that once a layer of predetermined thickness has been formed, the substrate can be exposed to a treatment environment for an ammonia plasma treatment (0090 and Fig. 4-5). They teach that each processing section is separated by a gas curtain or purge gas port (0079 and Fig. 5). Therefore, since each processing environment is separated by a purge port, the substrate will be exposed to a purge gas after the silicon precursor exposure, after the N2 plasma reactant for forming the SiN film, and after the ammonia plasma treatment before repeating the process.
From the teachings of Li, it would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to have modified the process of Nguyen to have deposited the SiN film on 3D features for forming spacers as in the method of Li so as to expose the substrate to the precursor of Nguyen, purged the reactor with an inert gas, exposed the substrate to a N2 plasma reactant for forming the SiN film, purged the reactor, exposed the substrate to an argon (inert)/ammonia plasma for modifying and further forming the SiN film with different etch selectivities, and then to have purged the reactor before repeating the process because Li teaches that such a process is desirable for forming selective spacer films such that it will be expected to provide a desirable method for forming SiN spacer films. Further, since Nguyen teaches performing the process at a temperature of about 50, 100, 200, 250, or 300°C to about 400, 450, or 500°C (0040) and Li teaches performing the process at a temperature of 200-500°C, it would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to have optimize the temperature to be within the claimed range from ranges of Nguyen and Li so as to have provided a desirable temperature for the deposition and treatment processes. According to MPEP 2131.03, “[W]hen, as by a recitation of ranges or otherwise, a claim covers several compositions, the claim is ‘anticipated’ if one of them is in the prior art.” Titanium Metals Corp.v. Banner, 778 F.2d 775, 227 USPQ 773 (Fed. Cir. 1985) (citing In re Petering, 301 F.2d 676, 682, 133 USPQ 275, 280 (CCPA 1962)) (emphasis in original). According to MPEP 2144.05, “in the case where the claimed ranges “overlap or lie inside ranges disclosed by the prior art” a prima facie case of obviousness exists.” In re Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976). According to MPEP 2144.05 II A, “Generally, differences in concentration or temperature will not support the patentability of subject matter encompassed by the prior art unless there is evidence indicating such concentration or temperature is critical. “[W]here the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation.” In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955).
While Nguyen in view of Li do not teach that that ammonia plasma further reacts with the chemisorbed layer to form the SiN film, since they provide a N2 first plasma and an ammonia second plasma as required by claims 19 and 21, the process is also expected to result in the ammonia plasma further reacting with the chemisorbed layer to form the SiN film. According to MPEP 2112.01 I, “Where the claimed and prior art products are identical or substantially identical in structure or composition, or are produced by identical or substantially identical processes, a prima facie case of either anticipation or obviousness has been established. In re Best, 562 F.2d 1252, 1255, 195 USPQ 430, 433 (CCPA 1977)”.
Regarding claim 15, Nguyen suggests the process of claim 1. They further teach after deposition, performing a plasma treatment to engineer film properties (0043). They teach exposing the SiN film to a plasma treatment once about 10 to about 40 angstroms of film have been deposited and repeating the process until the desired film thickness has been achieved (0052 and 0053). They teach that reducing agents include NH3, H2, and N2 (0034).
They do not teach that the plasma comprises hydrogen, inert gas, or nitrogen.
As discussed above for claim 19, Li provides the suggestion of performing a first nitrogen plasma and a second ammonia/argon (inert) gas plasma. Further, as noted above for claim 19, the temperature is suggested to be optimized to be within the claimed range.
Claim 7 is rejected under 35 U.S.C. 103 as being unpatentable over Nguyen as applied to claim 1 above, and further in view of Nakata, US 2015/0294975 A1.
Regarding claim 7, Nguyen suggests the process of claim 1.
They do not teach the features of claim 7.
Nakata teaches forming a barrier insulating film at an interface between and insulating film and a buried wiring line in a trench for use in a semiconductor device (abstract). They teach using a silicon oxide film as a first insulating film 11A (0072 and Fig. 1C). They teach using barrier insulating film 11B disposed on the surface of the first insulating layer, where the barrier insulating film 11B can be formed using a single-layer film or a laminated film comprising SiN, SiON, etc. (0073 and Fig. 1C). They teach forming the barrier insulating film 11B by PEALD when a SiN film or a SiON film is desired (0143-0146). Nakata further teaches when forming a SiON barrier layer, they provide a SiN film and then expose the film to ozone as an oxidizing gas so as to oxidize the SiN film to form SiON (0148). They teach that all steps of the process are implemented at a temperature in a range of between 450 and 550°C (0147). They teach repeating the steps of forming the SiN film and oxidizing it 6 times (0147).
From the teachings of Nakata, it would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to have modified the process of Nguyen to have deposited the SiN film in a trench as a barrier layer 11B as in the process of Nakata and to have exposed the SiN film to ozone, i.e., an oxygen source, at a temperature in the range of 450-550°C for forming an SiON barrier layer because Nakata teaches that such process provides a desirable barrier layer by oxidizing SiN to SiON such that it will be expected to provide a desirable application for the SiN film.
Further, Nakata teaches performing the oxidation step in the same chamber as deposition (0148), such that it would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to have converted the SiN film to the SiON film in situ because Nakata indicates that both steps can be performed in the same chamber.
Claim 14 is rejected under 35 U.S.C. 103 as being unpatentable over Nguyen as applied to claim 1 above, and further in view of Lei, US 2016/0122869 A1.
Regarding claim 14, Nguyen suggests the process of claim 1. They further teach after deposition, performing a plasma treatment to engineer film properties (0043).
They do not teach performing a thermal anneal.
As discussed above, Lei teaches depositing silicon-based films (abstract), where the films can include silicon nitride (0062). Lei further teaches that the silicon-containing films are exposed to a post-deposition treatment such as a thermal anneal at one or more temperatures ranging from about 500 to about 1000°C (0062). They teach performing the thermal anneal as an alternative to a plasma treatment (0062).
From the teachings of Lei, it would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to have exposed the SiN films to a thermal anneal at a temperature from about 500 to about 1000°C because Lei teaches that such a post-deposition treatment is desirable for SiN films as an alternative to a plasma treatment such that it will be expected to desirably engineer the film properties. Therefore, a thermal anneal will be performed at a temperature within the claimed range. According to MPEP 2131.03, “[W]hen, as by a recitation of ranges or otherwise, a claim covers several compositions, the claim is ‘anticipated’ if one of them is in the prior art.” Titanium Metals Corp.v. Banner, 778 F.2d 775, 227 USPQ 773 (Fed. Cir. 1985) (citing In re Petering, 301 F.2d 676, 682, 133 USPQ 275, 280 (CCPA 1962)) (emphasis in original).
Claim 17 is rejected under 35 U.S.C. 103 as being unpatentable over Nguyen in view of Nakata as applied to claim 7 above, and further in view of Jung, US 2005/0233598 A1.
Regarding claim 17, Nguyen in view of Nakata suggest the process of claim 7.
They do not teach performing a plasma treatment on the SiON film.
Jung teaches forming a stack including a first dielectric layer and a second dielectric layer by ALD with a post-treatment step performed to the stacked layers (abstract). They teach that the dielectric layer may be formed of SiON (0013). They teach that the post-treatment of the stacked dielectric layer is performed to remove impurities in the stacked dielectric layer (0015). They teach that the post-treatment is performed by a heat-treatment in a substantially inert atmosphere, heat-treatment in a hydrogen atmosphere, plasma treatment in a hydrogen atmosphere or any combination of two or more of these carried out simultaneously or in any suitable order (0016). They teach performing heat treatments at 150°C (0044), 450°C, 500°C, 600°C, 700°C, and 750°C (Table 1). From this, it would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to have optimized the heat treatment in the range of 150-750°C because Jung teaches that such temperatures are used for performing heat treatments, suggesting that such a range will provide suitable heating.
From the teachings of Jung, it would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to have modified the process of Nguyen in view of Nakata to have performed a hydrogen plasma treatment on the SiON film at a temperature optimized to be within the claimed range from the overlapping temperature range suggested by Jung because Jung teaches that hydrogen heat-treatment and hydrogen plasma treatments reduce impurities in SiON, where the treatments can be performed simultaneously such that it will be expected to reduce any impurities in the SiON film. Therefore, the SiON film will be treated with a hydrogen plasma at a temperature optimized to be within the claimed range from the overlapping range suggested by Jung. According to MPEP 2144.05, “in the case where the claimed ranges “overlap or lie inside ranges disclosed by the prior art” a prima facie case of obviousness exists.” In re Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976). According to MPEP 2144.05 II A, “Generally, differences in concentration or temperature will not support the patentability of subject matter encompassed by the prior art unless there is evidence indicating such concentration or temperature is critical. “[W]here the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation.” In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955).
Claims 19 and 20 are rejected under 35 U.S.C. 103 as being unpatentable over Nguyen, US 2014/0273529 A1 in view of Chen, US 2017/0372886 A1.
Regarding claims 19 and 20, Nguyen suggests the process of claim 1, so as to provide steps a)-e) of claim 19. They further teach after deposition, performing a plasma treatment to engineer film properties (0043). They teach exposing the SiN film to a plasma treatment once about 10 to about 40 angstroms of film have been deposited and repeating the process until the desired film thickness has been achieved (0052 and 0053). They teach that reducing agents include NH3, H2, and N2 (0034).
They do not teach that the plasma comprises hydrogen, inert gas, or nitrogen.
As discussed above, from the teachings of Chen, it would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to have modified the process of Nguyen to have deposited the SiN films on a substrate having three-dimensional features such as in FinFET applications and to have performed the nitrogen plasma treatment after each cycle of SiN deposition because Chen teaches that SiN films are desirably deposited on 3D substrate features for FinFET application and that a nitrogen plasma treatment after each cycle of SiN deposition by PEALD with an ammonia plasma reactant improves the SiN film quality. Therefore, in the process of Nguyen in view of Chen, the process of forming the SiN film by PEALD will include providing a substrate comprising a feature into a reactor, introducing a silicon precursor meeting the claimed requirements so as to chemisorb onto the substrate, purging the reactor, providing a first plasma comprising ammonia to the reactor to react with the chemisorbed layer to form a SiN film, purging the reactor, providing a second plasma comprising nitrogen that will react with the film to densify it so as to further form a densified SiN, purging the reactor, and repeating the process until a desired thickness of the film is deposited. Further, since Nguyen teaches performing PEALD at a range from about 50, 100, 200, 250, or 300°C to about 400, 450, or 500°C and Chen teaches performing the PEALD process from 25°C to 700°C or from 200-400°C, it would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to have optimized the temperature to be within the claimed range from the ranges overlapping or within the claimed range provided by Nguyen and Chen so as to provide a desirable temperature for the process. According to MPEP 2131.03, “[W]hen, as by a recitation of ranges or otherwise, a claim covers several compositions, the claim is ‘anticipated’ if one of them is in the prior art.” Titanium Metals Corp.v. Banner, 778 F.2d 775, 227 USPQ 773 (Fed. Cir. 1985) (citing In re Petering, 301 F.2d 676, 682, 133 USPQ 275, 280 (CCPA 1962)) (emphasis in original). According to MPEP 2144.05, “in the case where the claimed ranges “overlap or lie inside ranges disclosed by the prior art” a prima facie case of obviousness exists.” In re Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976). According to MPEP 2144.05 II A, “Generally, differences in concentration or temperature will not support the patentability of subject matter encompassed by the prior art unless there is evidence indicating such concentration or temperature is critical. “[W]here the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation.” In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955).
While Nguyen in view of Chen do not teach that that ammonia plasma further reacts with the chemisorbed layer to form the SiN film, since they provide an ammonia first plasma and a nitrogen second plasma as required by claims 19 and 20, the process is also expected to result in the ammonia plasma further reacting with the chemisorbed layer to form the SiN film. According to MPEP 2112.01 I, “Where the claimed and prior art products are identical or substantially identical in structure or composition, or are produced by identical or substantially identical processes, a prima facie case of either anticipation or obviousness has been established. In re Best, 562 F.2d 1252, 1255, 195 USPQ 430, 433 (CCPA 1977)”.
Double Patenting
The nonstatutory double patenting rejection is based on a judicially created doctrine grounded in public policy (a policy reflected in the statute) so as to prevent the unjustified or improper timewise extension of the “right to exclude” granted by a patent and to prevent possible harassment by multiple assignees. A nonstatutory double patenting rejection is appropriate where the conflicting claims are not identical, but at least one examined application claim is not patentably distinct from the reference claim(s) because the examined application claim is either anticipated by, or would have been obvious over, the reference claim(s). See, e.g., In re Berg, 140 F.3d 1428, 46 USPQ2d 1226 (Fed. Cir. 1998); In re Goodman, 11 F.3d 1046, 29 USPQ2d 2010 (Fed. Cir. 1993); In re Longi, 759 F.2d 887, 225 USPQ 645 (Fed. Cir. 1985); In re Van Ornum, 686 F.2d 937, 214 USPQ 761 (CCPA 1982); In re Vogel, 422 F.2d 438, 164 USPQ 619 (CCPA 1970); In re Thorington, 418 F.2d 528, 163 USPQ 644 (CCPA 1969).
A timely filed terminal disclaimer in compliance with 37 CFR 1.321(c) or 1.321(d) may be used to overcome an actual or provisional rejection based on nonstatutory double patenting provided the reference application or patent either is shown to be commonly owned with the examined application, or claims an invention made as a result of activities undertaken within the scope of a joint research agreement. See MPEP § 717.02 for applications subject to examination under the first inventor to file provisions of the AIA as explained in MPEP § 2159. See MPEP § 2146 et seq. for applications not subject to examination under the first inventor to file provisions of the AIA . A terminal disclaimer must be signed in compliance with 37 CFR 1.321(b).
The filing of a terminal disclaimer by itself is not a complete reply to a nonstatutory double patenting (NSDP) rejection. A complete reply requires that the terminal disclaimer be accompanied by a reply requesting reconsideration of the prior Office action. Even where the NSDP rejection is provisional the reply must be complete. See MPEP § 804, subsection I.B.1. For a reply to a non-final Office action, see 37 CFR 1.111(a). For a reply to final Office action, see 37 CFR 1.113(c). A request for reconsideration while not provided for in 37 CFR 1.113(c) may be filed after final for consideration. See MPEP §§ 706.07(e) and 714.13.
The USPTO Internet website contains terminal disclaimer forms which may be used. Please visit www.uspto.gov/patent/patents-forms. The actual filing date of the application in which the form is filed determines what form (e.g., PTO/SB/25, PTO/SB/26, PTO/AIA /25, or PTO/AIA /26) should be used. A web-based eTerminal Disclaimer may be filled out completely online using web-screens. An eTerminal Disclaimer that meets all requirements is auto-processed and approved immediately upon submission. For more information about eTerminal Disclaimers, refer to www.uspto.gov/patents/apply/applying-online/eterminal-disclaimer.
Claims 1, 4-7, 14, 15, 17, and 19-21 are provisionally rejected on the ground of nonstatutory double patenting as being unpatentable over claims 1-24 of copending Application No. 17/281898 (US PG-PUB 2021/0398796 A1) in view of McSwiney, US 2005/0025885 A1.
Copending claim 1 provides the features of instant claim 1 of forming a silicon nitride film by PEALD by performing claims steps a)-e) at a temperature range overlapping the claimed range and repeating steps b) through e) until the desired film thickness is reached. While the copending claim does not indicate that any unreacted silicon precursors and/or any reaction by products are purged in step (c) or that any further reaction by products are purged in step (e), since the process provides the purging steps, these materials are also expected to be purged. While the copending claims do not specify the amount of carbon in the film, since they provide the claimed processing steps, the film is also expected to include 5 at.% or less of carbon.
The copending application teaches performing step b) with a different precursor such that it does not provide the claimed precursor.
McSwiney teaches a method of combining a silicon source precursor and a nitrogen source precursor at a temperature up to 550°C for forming a silicon nitride film (abstract). They teach that suitable nitrogen sources include ammonia as well as more reactive nitrogen sources (0018). They teach that suitable silicon sources include silyl hydrocarbons (0019). They teach that precursors include silicon atoms bridged by hydrocarbon fragments (0043). They teach that examples include 1,2-bis(trichlorosilyl)ethane (i.e., 1,1,1,4,4,4,-hexachloro-1,4-disilabutane) and 1,2-bis(dichloro(methyl)silyl)ethane (i.e., 2,2,5,5,-tetrachloro-2,5-disilahexane) (0050 and Fig. 8). They teach that the precursors facilitate a lower silicon nitride formation temperature and include increased bond strain and increased functional group reactivity (0052).
From the teachings of McSwiney, it would have been obvious to a person having ordinary skill in the art to have modified copending claim 1 to have used 1,1,1,4,4,4,-hexachloro-1,4-disilabutane or 2,2,5,5,-tetrachloro-2,5-disilahexane as the silicon precursor for forming the SiN film because McSwiney teaches that such precursors facilitate a lower silicon nitride formation temperature and include increased bond strain and increased functional group reactivity such that it will provide a simple substitution of one known precursor for another for forming a SiN with the expected benefits described by McSwiney. Therefore, copending claim 1 in view of McSwiney suggests using a precursor meeting the requirements of instant claims 2 and 22.
Further, copending claims 3-6, 13, 14, and 16 in view of McSwiney provide the limitations of instant claims 4-7, 14, 15, and 17, respectfully.
Copending claim 18 provides the features of instant claim 19, where McSwiney provides the suggestion of using the precursor of instant claims 19 and 22. Copending claims 19 and 20 in view of McSwiney provide the limitations of instant claims 20 and 21. Further, since the copending claim in view of McSwiney provides the claimed processing steps, the resulting film is also expected to have 5 at. % or less of carbon.
This is a provisional nonstatutory double patenting rejection.
Response to Arguments
Applicant's arguments filed 10/24/2025 have been fully considered but they are not persuasive.
While Lei provides an embodiment where the silicon-containing film includes 35-100% carbon, as discussed in the rejection above, they also provide an embodiment of forming a silicon nitride film, where the film can include 0-50% carbon by atomic weight percent so as to have a carbon concentration overlapping the claimed range. Further Lei teaches that the film formed is selected from the group consisting of silicon carbide, silicon nitride, and silicon carbonitride (0055), indicating that in other embodiments, the film can be silicon nitride so as to provide no carbon in the film. Note MPEP 2123(II): Disclosed examples and preferred embodiments do not constitute a teaching away from a broader disclosure or nonpreferred embodiments. In re Susi, 440 F.2d 442, 169 USPQ 423 (CCPA 1971). "A known or obvious composition does not become patentable simply because it has been described as somewhat inferior to some other product for the same use." Therefore, while the examples of Lei provide a silicon nitride film having carbon, since they also indicate that the film can include 0% carbon and that the film can be a silicon nitride film, this is considered to suggest forming a SiN film with a carbon concentration within the claimed range.
Further, Lei teaches that the atomic weight percentage of carbon and nitrogen can be tuned by changing deposition conditions such as temperature, adding a nitrogen source, or combinations thereof (0006), providing the suggestion to optimize the concentration of carbon and nitrogen in the film, such that when forming a SiN film as opposed to a SiCN film it would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to have optimized the concentration of carbon to be minimal so as to be within the claimed range to provide the desired film.
Lei is considered to be sufficient to enable a person of ordinary skill in the art to form a silicon nitride film because they teach that such a film can be formed and they indicate how the concentration of the carbon can be tuned using the deposition parameters. Further, McSwiney provides the suggestion of using precursors that form a silicon nitride film, such that the combination of Lei and McSwiney is expected to suitably enable one of ordinary skill in the art to deposit a silicon nitride film with the claimed carbon concentration.
Regarding Applicant’s arguments over the deposition methods or parameters of McSwiney, it is noted that they teach using a deposition temperature of up to 550°C so as to overlap the range of Lei, using ammonia as a reactant, using ALD or PECVD chambers for deposition, where the films deposited include silicon nitride films. The precursors of McSwiney are also similar to those taught by Lei such that the deposition methods and temperatures are expected to be similar to that of Lei.
Regarding Applicant’s argument that Nguyen fails to disclose any of the compounds recited in the pending claims, and further fails to recite any parameters for a desirable film such as concentration of carbon, nitrogen, or other elements or compounds in the film, as outlined above, Nguyen teaches using a formula having overlapping constituents so as to include 1,1,1,4,4,4,-hexachloro-1,4-disilabutane, depositing the film using a temperature within the claimed range at a pressure within or overlapping the ranges in the instant specification, using plasma powers meeting the powers used in the instant specification, and using a direct plasma having a frequency meeting that described in the instant specification so as to form a silicon nitride film, such that the resulting film is also expected to have the claimed carbon content. As noted above, since Nguyen teaches forming a silicon nitride film, one having ordinary skill in the art would be motivated to optimize the film to have a minimal carbon content so as to provide a silicon nitride film as opposed to a carbon doped silicon nitride film.
Further, Nguyen is considered to enable someone to perform the claimed method because they provide forming a silicon nitride film such a precursor formula with constituents overlapping a range so as to read on at least one of the claimed precursors, using the claimed deposition steps, with deposition conditions within or overlapping those described in the specification such that the resulting film is also expected to have the claimed carbon content.
Further, the Terminal Disclaimer of 8/31/2024 was not approved as described in the Office Action dated 11/5/2024 and therefore, the double patenting rejection is upheld.
Conclusion
THIS ACTION IS MADE FINAL. Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to CHRISTINA D MCCLURE whose telephone number is (571)272-9761. The examiner can normally be reached Monday-Friday, 8:30-5:00 EST.
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/CHRISTINA D MCCLURE/Examiner, Art Unit 1718 /GORDON BALDWIN/Supervisory Patent Examiner, Art Unit 1718