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 1-19 are pending and rejected.
Drawings
The drawings are objected to as failing to comply with 37 CFR 1.84(p)(5) because they include the following reference character(s) not mentioned in the description: 700a from Fig. 7. Corrected drawing sheets in compliance with 37 CFR 1.121(d), or amendment to the specification to add the reference character(s) in the description in compliance with 37 CFR 1.121(b) are required in reply to the Office action to avoid abandonment of the application. Any amended replacement drawing sheet should include all of the figures appearing on the immediate prior version of the sheet, even if only one figure is being amended. Each drawing sheet submitted after the filing date of an application must be labeled in the top margin as either “Replacement Sheet” or “New Sheet” pursuant to 37 CFR 1.121(d). If the changes are not accepted by the examiner, the applicant will be notified and informed of any required corrective action in the next Office action. The objection to the drawings will not be held in abeyance.
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, 2, and 5-12 are rejected under 35 U.S.C. 103 as being unpatentable over Kang, US 2022/0102190 A1 in view of Ueda, US 10,381,219 B1 OR Kuroda, US 2019/0249303 A1.
Regarding claim 1, Kang teaches a method (a method of forming an air gap, abstract) comprising:
providing a structure comprising features and an open gap between the features, the open gap including sidewall and bottom surfaces (providing a substrate having a patterned structures, where the patterned structure includes a stepped structure having an upper surface, a lower surface, and a side surface connecting the upper surface and the lower surface, where it may include a plurality of protrusions defined by a plurality of recesses, 0002, 0048-0049, 0085, Fig. 1, and Fig. 3, where multiple features are depicted, Fig. 3); and
performing multiple plasma enhanced atomic layer deposition (PEALD) cycles (where PEALD is used to form a second insulating layer, 0055, where the steps are repeated, 0074 and Fig. 1-3), each cycle comprising:
a) exposing the structure to a dose of a silicon-containing precursor to allow the silicon-containing precursor to adsorb on sidewall and bottom surfaces of the open gap (supplying a second silicon-containing source gas on the patterned structure, 0056, Fig. 1-3, where a silicon source molecular layer is formed, 0056, 0091 and Fig. 3, such that the silicon-containing precursor is understood to adsorb onto the sidewall and bottom surfaces of the gap so as to form a monolayer as depicted in Fig. 3); and
b) exposing the adsorbed silicon-containing precursor to a plasma generated from a process gas comprising a co-reactant and one or more dilution gases, to react the co-reactant with the adsorbed silicon-containing precursor and form a dielectric material, where the dielectric material is preferentially formed near a top of the open gap (where a second reaction gas having reactivity with the second silicon molecular layer is provided, 0056 and Fig. 1-3, where second reaction gas is provided in a plasma atmosphere, 0068, 0092, and Fig. 2-3, where the reaction gas can include a dilution gas, 0041, and where the second reaction gas has reactivity with the silicon molecular layer to form the second insulating layer, 0056, 0068, 0092, and Fig. 1-3, and where the second insulating layer is formed to have a step coverage lower than the first insulating film so as to use an overhang property of the films to form an air gap by crosslinking the thin films in an upper portion of the gap structure, abstract, 0006, 0058, and Fig. 3, such that the dielectric material is preferentially formed near a top of the open gap).
They do not teach that the reactive gas is provided with the dilution gas having a ratio meeting the claimed requirements.
Kang teaches that the second insulating film may be silicon nitride, silicon oxide, or a combination thereof (0056). They teach that the second reactant may be oxygen and/or nitrogen (0056).
Ueda teaches methods for forming a silicon nitride film by a PEALD process that includes providing a substrate and performing at least one unit deposition cycle of a PEALD process (abstract). They teach that the unit cycle comprises contacting the substrate with a silicon precursor and contacting the substrate with a reactive species generated from a gas mixture comprising a nitrogen precursor and an additional gas (abstract). They teach that the additional gas comprises at least one of helium or neon, where the flow rate ratio of additional gas to nitrogen precursor is greater than 4:1, or greater than 10:1 or greater than 15:1 or even equal to or greater than 20:1 (Col. 1, lines 50-64 and Col. 8, lines 3-25). They teach that the percentage of volume of the additional gas within the gas mixture may be greater than 70%, or greater than 85% , or even greater than 90%, where it may be between approximately 70% to approximately 90% (Col. 8, lines 3-25). They teach that the gas mixture may consist essentially of the nitrogen precursor and helium, where the volume ratio of helium to nitrogen precursor is equal to or greater than approximately 6:1 (Col. 8, lines 26-45). Therefore, the flow rate ratios are understood to be in terms of the volumetric flow rate ratio since they indicate that the ratio is the volume ratio. They teach that the flow rate ratio provides an increased population density of reactive species such as atomic nitrogen, nitrogen radicals, and/or excited nitrogen species (Col. 8, lines 46-65). They teach that the increased population density of reactive species reduces the time period required for the reaction with the absorbed monolayer of silicon species to form the silicon nitride film thereby reducing the plasma exposure time and the overall time period required to deposited a silicon nitride film to a desired thickness (Col. 8, lines 46-65).
From the teachings of Ueda, 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 provided the nitrogen reactant gas plasma with helium or neon as a dilution gas at a volumetric flow rate ratio of dilution gas ratio to nitrogen precursor in the range of greater than 4:1, or greater than 10:1 or greater than 15:1 or even equal to or greater than 20:1 because Ueda teaches that such a ratio provides the benefits of increasing the population density of reactive species so as to reduce the time period required for the reaction with the absorbed monolayer of silicon species to form the silicon nitride film thereby reducing the plasma exposure time and the overall time period required to deposited a silicon nitride film to a desired thickness. Therefore, the volumetric flow rate ratio of the one or more dilution gas to the co-reactant overlaps or is within the range of claims 1 and 6-8. 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.” 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).
Alternatively: Kuroda teaches a chemical precursor and a method for depositing a silicon oxide film on a surface within a reaction space by PEALD (abstract). They teach that the precursor may be utilized with an oxygen-based reactant to form a pure silicon oxide film or a nitrogen silicon oxide (0043). They teach that the PEALD process may utilize a constant carrier gas flow (0050). They teach that by using a constant carrier flow, the variation in total gas flow entering the reaction space between the precursor feed step and the other steps of the PEALD cycle may be reduced, which may also reduce pressure instability in the PEALD process (0050). They teach that the PEALD process comprises introducing one or more inert gases and a reactant gas into the reaction space, where the inert carrier gas may comprise at least one of hydrogen, nitrogen, helium, argon, or mixtures thereof (0052). They each providing the inert gas to the reaction space using a flow rate of greater than 1 slm, or greater than 4 slm, or even greater than 10 slm (0052). They teach that in addition to the inert carrier gas, a reactant gas may also be introduced into the reaction space, where the reactant gas is for depositing silicon oxide, or a doped silicon oxide film (0053). They teach that the reactant gas may comprise at least one of N2, O2, N2O, etc. (0053). They teach that the flow rate of the reactant gas into the reaction space maybe greater than 0.1 slm, or greater than 1 slm, or even greater than 5 slm (0053).
From the teachings of Kuroda, 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 used a constant carrier gas flow rate in the PEALD process with a flow rate of greater than 1 slm, or greater than 4 slm, or even greater than 10 slm and a reactant flow rate of greater than 0.1 slm, or greater than 1 slm, or even greater than 5 slm because Kuroda teaches that a constant flow rate of carrier is desirable for reducing variation in total gas flow entering the reaction space and pressure instability in a PEALD process of forming silicon oxide or silicon oxynitride, where such flow rates are suitable such that it will be expected to provide suitable flow rates for the process. Therefore, the volumetric flow rate ratios of dilution (carrier) gas to reactant will overlap the ranges of claims 1 and 6-8. For example, a 1 slm flow rate for the reactant and a 10 slm flow rate for the dilution gas will provide a 10:1 ratio and a 0.2 slm reactant flow rate and a 10 slm dilution gas flow rate will provide a 50:1 ratio.
Regarding claim 2, Kang in view of Ueda OR Kuroda suggest the process of claim 1. Kang teaches performing the deposition process for forming air gaps (abstract and Fig. 3), such that the process comprises closing the open gas with the deposited dielectric material, thereby forming a closed air gap between the features.
Regarding claim 5, Kang in view of Ueda OR Kuroda suggest the process of claim 1. Kang further teaches purging the second silicon-containing source gas before supplying the second reaction gas (0018, 0056). Therefore, the chamber will be purged so as to remove the second-silicon source gas between (a) and (b).
Regarding claims 9-11, Kang in view of Ueda OR Kuroda suggest the process of claim 1. Kang further teaches using oxygen as a reactant (0056), where the film is silicon oxide, silicon nitride, or a combination thereof (0056).
Kuroda further teaches using at least one of oxygen, N2O, N2, etc. as the reactant in forming a silicon oxide or silicon oxynitride film (0043 and 0053).
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 used nitrous oxide, oxygen, or a combination thereof in forming the film because Kang indicates that oxygen can be used and Kuroda indicates that oxygen, nitrous oxide, or a combination can be used for forming a silicon oxide or silicon oxynitride film such that it will be expected to provide suitable reactants for the process.
Regarding claim 12, Kang in view of Ueda OR Kuroda suggest the process of claim 1. Kang further teaches using nitrogen as a reactant (0056), where the film is silicon oxide, silicon nitride, or a combination thereof (0056).
Ueda teaches using a nitrogen precursors such as N2 (Col. 8, lines 3-25). Therefore, the reactant will be N2.
Claims 3, 4, and 13 are rejected under 35 U.S.C. 103 as being unpatentable over Kang in view of Ueda OR Kuroda as applied to claim 2 above, and further in view of Ho, US 2022/0231023 A1.
Regarding claims 3 and 4, Kang in view of Ueda OR Kuroda suggest the process of claim 2.
They do not teach that a top of the closed air gap is below tops of the features.
Ho teaches a FINET device that includes a fin extending from a semiconductor substrate and including an air gap between a spacer and a contact plug, where a portion of a dielectric layer seals the top of the air gap (abstract and 0009). They teach that an etch stop layer 122 is formed over the second ILD 108, the source/drain contacts 118, and over the initial air gaps 120’ (0057 and Fig. 22). They teach that the ESL 122 may be formed as a blanket layer extending across the initial air gaps 120’, such that the initial air gaps 120’ are enclosed and form air gaps 120 (0057 and Fig. 22). They teach that the ESL 122 partially extends into the initial air gaps and can be used as an etch stop layer during the formation of conductive features 136 on the source/drain contacts 118 (0057 and Fig. 22). They teach that the ESL 122 may comprise one or more layers of materials such as silicon nitride, silicon oxynitride, etc. and may be deposited by PEALD (0058). They teach that the ESL 122 is formed extending into and sealing the initial air gaps, where portions of the ESL extended into the initial air gaps form sealing regions 123’ extending a vertical distance D1 (0058 and Fig. 22).
They teach applying a photoresist and patterning the structure, where the ESL 122 is used as an etch stop layer and portions of the sealing regions 123’ may also be removed resulting in recesses 139 that extend into the initial air gaps (0067-0068 and Fig. 26B). They teach that the etching process is controlled such that the air gaps are still sealed by remaining portions of the sealing regions after forming openings 138 (0068 and Fig. 26B). They teach that the remaining portions of the sealing regions prevent the air gaps from being exposed (0068). They teach that the recesses 139 may extend a vertical distance D2 into the initial air gaps that is between about 0 nm and about 15 nm (0068 and Fig. 26B). They teach that the presence of the seals protects the air gaps and blocks subsequently formed conductive material from entering the air gaps, which can reduce the chance of leakage (0069). Therefore, they teach forming a semiconductor device having air gaps formed by PEALD, where the air gaps can be silicon nitride or silicon oxynitride, where the device is patterned so that the top of the closed air gap is 0 to 15 nm below the tops of the features.
From the teachings of Ho, 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 Kang in view of Ueda OR Kuroda to have used the PEALD process in the formation of a FINFET as in the process of Ho and to have patterned the structure so that the top of the closed air gap is 0 to 15 nm below the features because Ho teaches that such a process is desirable in forming FINET devices, where the air gaps are formed using a PEALD process such that it will be expected to provide a desirable device and air gap. Therefore, the top of the closed air gap will be below the top of the features in a range overlapping the range of claim 4. 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.”
Regarding claim 13, Kang in view of Ueda OR Kuroda suggest the process of claim 1. Kang teaches that the insulating layer is formed with a low step coverage, where power may be applied for a short time such as 0.1 second to 1 second (0084). They provide an example of providing the source for 0.1 seconds to 1 second and the RF power for 0.1 seconds to 1 seconds (Table 1). As discussed above for claim 1, they teach forming a molecular layer of silicon on the structure (0018 and Fig. 3).
They do not teach that the duration of (a) in each cycle is at least twice a duration of (b).
Ho teaches that the distance D1 may be controlled by controlling parameters of the ESL 122 material deposition process (0058). They teach that by controlling the deposition of the ESL 122 such that sealing regions 123’ extend into the initial air gaps, subsequently deposited conductive material of the conductive features may be blocked from filling or partially filling the initial air gaps, and thus capacitive benefits of the air gaps maybe preserved while also reducing the chance of leakage between the conductive features and the gate stack (0059 and Fig. 22). They teach that the parameters of the ALD process may be controlled to control the distance D1 that the sealing regions extend into the initial air gaps (0060). They teach that the distance D1 may be controlled by controlling the dose (e.g., the pressure and/or pulse duration) of one or more precursors of the ALD process (0060). They teach that larger doses can allow the precursor to reach and react with surfaces deeper within the initial air gaps, whereas smaller doses may limit the growth of the material to surfaces near the top of the initial air gaps (0060). They teach that when the process is a PEALD process, the duration of time that the RF power is applied in a half-cycle may be controlled to control formation of the sealing regions 123’ (0063). They teach that decreasing the RF duration decreases the number of reactive precursor species generated, as shorter RF power duration may form sealing regions 123’ extending a smaller distance D1, whereas a longer RF power duration may form sealing regions 123’ extending a larger distance D1 (0063 and Fig. 23A-B). They teach that the precursor pressure, pulse duration, RF power duration, and/or other parameters may be controlled in other combinations or other variations to control the formation of the sealing regions 123’ (0063). They teach that using silicon-forming precursors with nitrogen-forming precursors such as N2, NH3, and the like (0064). They each that the silicon precursor is provided for a pulse duration that is between about 0.1 seconds and 0.5 seconds and the nitrogen precursor is provided for a pulse duration that is between about 0.1 seconds and 1 second with RF power (0064).
From the teachings of Kang and Ho, 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 duration of step (a) and step (b) to be within the claimed range because Kang teaches forming a molecular layer on the structure in (a), indicating that the material is allowed a longer time to extend into the features (as taught by Ho) and Kang teaches providing a short duration for step (b) to provide low step coverage, where Ho indicates that a shorter duration of plasma reaction allows the material to be deposited at a shorter distance into a feature such that it will be expected to provide the air gaps being sealed at the surface as opposed to filling the gap. Further, Kang and Ho provide a range of precursor and RF pulses that overlaps a range in which step (a) is more than twice the duration of step (b), for example when step (a) is 0.5 second (in the range of Kang and Ho) and step (b) is 0.1 second (in the range of Kang and Ho). According to MPEP 2144.05 II A, “[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). 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.”
Claims 14 and 15 are rejected under 35 U.S.C. 103 as being unpatentable over Kang in view of Ueda OR Kuroda as applied to claim 2 above, and further in view of Ho, US 2022/0231023 A1 and Zhu, US 9,859,151 B1.
Regarding claims 14 and 15, Kang in view of Ueda OR Kuroda suggest the process of claim 2. Kang teaches that the second layer of insulating material can be formed without the formation of the first insulating material (0083).
They do not teach that area of the closed gap.
As discussed above, Ho provides the suggestion of controlling the PEALD process parameters to control the distance into the gap the sealing material is deposited.
Zhu teaches a method for depositing a film to form an air gap within a semiconductor device using selective deposition (abstract). They teach forming a larger air gap in that it can be a greater percentage of the trench, such as 50-60%, more than about 70% or more than about 80% of the size of the trench or the space between the metallization lines (Col. 2, line 63 to Col. 3, line 2). They teach that advantages gained from a larger air gap may include improved performance, and reducing the effective k-value of the material in between the lines (Col. 3, lines 56-67). Therefore, Zhu teaches that it is desirable to have a larger air gap, where the gap is desirably more than about 80% of the size of the trench or space between the metallization lines.
From the teachings of Ho and Zhu, 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 PEALD process parameters of Kang in view of Ueda OR Kuroda to have deposited the sealing material so that the air gap is formed so that it occupies at least 80% of the first area or 90% of the first area because Zhu teaches that it is desirable to have a larger air gap, where the gap is desirably more than about 80% of the size of the trench or space between the metallization lines, where having a large air gap provides improved performance and Ho indicates that the PEALD process parameters can be tuned to control the distance into the gap the material is deposited such that it will be expected to provide a desirable air gap for a device. Further, since they suggest forming the air gap using the process of claim 1, the process is expected to be capable of forming an air gap meeting the claimed requirements. According to MPEP 2144.05 II A, “[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 16 and 17 are rejected under 35 U.S.C. 103 as being unpatentable over Kang, US 2022/0102190 A1 in view of Ho, US 2022/0231023 A1 and Zhu, US 9,859,151 B1.
Regarding claims 16 and 17, as discussed above for claims 1, 2, 14, and 15, Kang in view of Ho, and Zhu provide the features of claims 16 and 17, where the area occupied by the closed air gap is optimized to be within the claimed ranges. According to MPEP 2144.05 II A, “[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 18 and 19 are rejected under 35 U.S.C. 103 as being unpatentable over Kang in view of Ho and Zhu as applied to claim 16 above, and further in view of Ueda, US 10,381,219 B1 OR Kuroda, US 2019/0249303 A1,
Regarding claim 18 and 19, Kang in view of Ho and Zhu suggest the process of claim 16. As discussed above for claims 1, 6, and 7, Ueda or Kuroda provide the suggestion of using flow rates overlapping or within the claimed ranges. 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.” 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).
Conclusion
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/CHRISTINA D MCCLURE/ Examiner, Art Unit 1718