DETAILED ACTION
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 .
This listing of claims will replace all prior versions, and listings, of claims in the application.
Continued Examination Under 37 CFR 1.114
A request for continued examination under 37 CFR 1.114, including the fee set forth in 37 CFR 1.17(e), was filed in this application after final rejection. Since this application is eligible for continued examination under 37 CFR 1.114, and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114. Applicant's submission filed on 02/04/2024 has been entered.
Response to Arguments
Applicant’s arguments, see Remarks filed 02/04/2024 with respect to the 35 USC 103 rejections have been fully considered and are persuasive.
Therefore, the rejection has been withdrawn. However, upon further consideration, a new ground(s) of rejection is made incorporating US 20210280686 A1 Amano et al hereafter “Amano” and US 20080230804 A1 Nishi et al “Nishi”.
Claim Rejections - 35 USC § 103
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.
Claims 1-7 and 9-11 are rejected under 35 U.S.C. 103 as being unpatentable over 20200075595 A1 Shin et al here after “Shin”, and further in view of US 10832904 B2 Varadarajan hereafter “Varadarajan” and US 20170077321 A1 Ito et al hereafter “Ito” and US 20080230804 A1 Nishi et al “Nishi”
Regarding claim 1 Shin teaches a method, comprising: forming first and second fin structures (AP1 and AP2 fig. 13B) on a substrate (100 fig. 13B);
forming n- and p-type source/drain (S/D) regions (SD2 and SD1 fig. 13B) on the first and second fin structures, respectively;
forming first and second contact openings (CNH of PR and NP regions fig. 13B) on the n- and p-type S/D regions, respectively;
forming a first carbon-based layer (CSP of PR and NP regions fig. 13B, sufficiently disclosed as carbon-based om paragraph [0033] “SiCN” and/or “SiCON”) with a first density (SiCN and/or SiCON must necessarily have a first density as it is a material) in the first and second contact openings;
forming a p-type work function metal (pWFM) silicide layer (sufficiently disclosed in paragraph [0042] “a silicide layer (not shown) may be interposed between the active contact AC and the first source/drain pattern SD1 and/or between the active contact AC and the second source/drain pattern SD2” and “The silicide layer may include metal silicide, for example, one or more of titanium silicide, tantalum silicide, tungsten silicide, nickel silicide, and cobalt silicide”) on the p-type S/D region; and forming an n-type work function metal (nWFM) silicide layer on the pWFM silicide layer (sufficiently disclosed in paragraph [0042] “a silicide layer (not shown) may be interposed between the active contact AC and the first source/drain pattern SD1 and/or between the active contact AC and the second source/drain pattern SD2” and “The silicide layer may include metal silicide, for example, one or more of titanium silicide, tantalum silicide, tungsten silicide, nickel silicide, and cobalt silicide”) and on the n-type S/D region;
selectively removing a portion [Paragraph 0077, 0076, 0068] as well as anisotropically etching the carbon-based layer [paragraph 0073 “the formation of the contact spacer CSP may include conformally forming a contact spacer layer to cover the inner sidewalls of the contact holes CNH and anisotropically etching the contact spacer layer”].
Shin does not teach performing a remote plasma treatment with radicals on the first carbon-based layer to form a second carbon-based layer with a second density greater than the first density;
nor the removing a portion of the second carbon-based layer;
nor depositing an n-type work function metal (nWFM) layer with a first nWFM layer portion on the pWFM silicide layer and a second nWFM layer portion on the n-type S/D region; converting the first nWFM layer portion into a first nWFM silicide layer on the pWFM silicide layer; and converting the second nWFM layer portion into a second nWFM silicide layer on the n-type S/D region
Varadarajan teaches a remote plasma treatment with radicals for carbon-based layer to form a remote second carbon-based layer [Column 1 lines 30-47 “The method further includes flowing a source gas into a remote plasma source, generating radicals of hydrogen in the remote plasma source from the source gas… to form SiCO film”]. Therefore, the combination of Shin and Varadarajan teaches removing a portion of the remote plasma treated layer.
Varadarajan further teaches the use of carbon-containing precursors (carrier gas) as part of the plasma treatment process [Paragraph 0017].
It would have been obvious to one of ordinary skill in the art to modify the process including a carbon-based layer as taught by Shin such that it includes “a remote plasma treatment with radicals on the first carbon-based layer to form a second carbon-based layer” to enable the formation of a high-quality carbon-based layer and reduce detrimental effects within the material [Column 3 line 55 to column 4 lines 48].
Ito teaches a protective layer (11 fig. 4A) comprising Silicon oxide hydrogen and carbon [Paragraph 0034] and the use of a CO.sub.2 (carbon dioxide) carrier gas during a treatment process to increase the density and/or concentration of carbon within the Silicon oxide [sufficiently disclosed paragraph 0112] to decrease the permeability of the protective layer [sufficiently disclosed Paragraph 0124].
As evidenced by Ito, the plasma treatment of Shin in view of Varadarajan would necessarily have increased the carbon density and/or concentration by using the carbon-containing precursors such that “second carbon-based layer” has “a second density greater than the first density”.
Alternatively, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the process of Shin in view of Varadarajan to increase the concentration and/or density of carbon within the second carbon-based layer relative to the first carbon based layer as part of the plasma-treatment process to improve the result effected variable of permeability and/or the insulative proprieties of the second carbon based layer as a part of routine optimization [see MPEP 2144.05 II A]
Nishi teaches depositing an n-type work function metal (nWFM) layer (Er Fig. 11A and/or 126 fig. 8 sufficiently disclosed paragraph 37 “a metal silicide that contains erbium (Er) or yttrium (Y) or the like” Er and Y are the same as disclosed in the instant application paragraph 0032) with a first nWFM layer portion(sufficiently illustrated fig. 11 and/or fig. 8) on the pWFM silicide layer (NiSi fig. 11A and/or 124 fig. 8, sufficiently disclosed paragraph 37 “a metal silicide, such as nickel silicide (NiSi)” NiSi is the same as disclosed in the instant application paragraph 0019) [sufficiently illustrated fig. 11A and 8] and a second nWFM layer portion (sufficiently illustrated fig. 8) on the n-type S/D region (102 fig. 8) [met under broadest reasonable interpretation of wherein “on” includes the use as “used as a function word to indicate position in close proximity with” Merriam-Webster dictionary]; converting the first nWFM layer portion into a first nWFM silicide layer (136 on 134 fig. 9 and/or (Er, Ni)Si fig.11A-11E) on the pWFM silicide layer; and converting the second nWFM layer portion into a second nWFM silicide layer (136 on 102 fig. 9) on the n-type S/D region [wherein the converting is a thermal process, sufficiently disclosed paragraph 0057 “thermal processing”].
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to take the method of Shin in view of Varadarajan and Ito and combine it with the method of Nishi such that “depositing an n-type work function metal (nWFM) layer with a first nWFM layer portion on the pWFM silicide layer and a second nWFM layer portion on the n-type S/D region; converting the first nWFM layer portion into a first nWFM silicide layer on the pWFM silicide layer; and converting the second nWFM layer portion into a second nWFM silicide layer on the n-type S/D region” occurs for the benefit of “in case majority carriers are electrons, an electrical current becomes relatively easier to flow between the second conductor and the diffusion layer, and thus the contact resistance becomes lower” and/or “in case the carriers are holes, it becomes difficult for electric current to flow with respect to the first conductor 114, resulting the contact resistance becoming higher” [Nishi paragraph 0043] and/or to improve the contact resistance between the contact and the source/drain regions and/or combining equivalents known for the same purpose is prima facie type obviousness [See MPEP 2144.06] in this case it is combing known methods of known for the purpose of forming a source/drain contact comprising a silicide layer.
Regarding claim 2 Shin in view of Varadarajan, Nishi and Ito teaches as shown above the method of claim 1, wherein forming the first carbon-based layer comprises exposing the first and second contact openings to a silicon-, oxygen-, hydrogen-, and carbon- containing precursor. [This limitation is met in view of Varadarajan Column 4 line 6 - Column 5 line 38 “Si--O”, “Si--C”, “Si--H”].
Regarding claim 3 Shin in view of Varadarajan, Nishi and Ito teaches as shown above the method of claim 1, wherein forming the first carbon-based layer comprises exposing the first and second contact openings to a precursor with silicon-carbon-silicon (Si-C Si) bonds, silicon-oxygen (Si-0) bonds, and silicon-methyl group (Si-CH3) bonds. [This limitation is met in view Varadarajan wherein the limitation is sufficiently illustrated in Fig. 4A-5A].
Regarding claim 4 Shin in view of Varadarajan, Nishi and Ito teaches as shown above the method of claim 1, wherein forming the first carbon-based layer comprises depositing a carbide layer with silicon-carbon (Si-C) bonds, silicon-oxygen (Si-0) bonds, terminal silicon-methyl group (Si-CH3) bonds, and terminal silicon-hydrogen (Si-OH) bonds. [This limitation is met in view Varadarajan wherein the limitation is sufficiently illustrated in Fig. 4A-5A].
Regarding claim 5 Shin in view of Varadarajan, Nishi and Ito as shown above the method of claim 1, wherein performing the remote plasma treatment with the radicals comprises exposing the first carbon-based layer to radicals of hydrogen and oxygen atoms. [This limitation is met in view of Varadarajan, “Hydrogen” column 1 lines 31 to 48 and “oxygen” sufficiently disclosed as being inherent to the process in column 3 lines 61 to column 4 lines 14].
Regarding claim 6 Shin in view of Varadarajan, Nishi and Ito teaches as shown above the method of claim 1, wherein performing the remote plasma treatment with the radicals comprises removing hydrogen atoms from the first carbon-based layer to form a hydrogen-free carbide layer. [an embodiment is sufficiently disclosed column 13 lines 21-42 “After exposure to an etch process, such as an O.sub.2/N.sub.2 strip process, the Si—CH.sub.3 bonds largely disappear. The terminal CH.sub.3 bonds may be readily removed so that the after the O.sub.2/N.sub.2 strip process, only Si—C bonds and Si—O—Si bonds largely remain”, and Varadarajan in column 18 lines 51 - Column 19 line 53 sufficient discloses an embodiment wherein then end material is a “carbide”].
Regarding claim 7 Shin in view of Varadarajan, Nishi and Ito teaches as shown above the method of claim 1, wherein performing the remote plasma treatment with the radicals comprises forming silicon-carbon (Si-C) bonds and silicon-oxygen (Si-0) bonds in the second carbon-based layer. [This limitation is met in view of Varadarajan Column 4 line 6 - Column 5 line 38 “Si--O”, “Si--C”, “Si--H”].
Regarding claim 9 Shin in view of Varadarajan, Nishi and Ito teaches as shown above the method of claim 1, wherein forming the first carbon-based layer is performed prior to performing the remote plasma treatment. [This limitation is met in view of Varadarajan column 1 line 60 to column 2 line 17, wherein forming the carbon-based layer is part of step (a) and the remote plasma treatment is part of step (b)].
Regarding claim 10 Shin in view of Varadarajan, Nishi and Ito teaches as shown above the method of claim 1, wherein forming the first carbon-based layer and performing the remote plasma treatment are performed substantially at a same time. [This claim is met in the same manner as claim 9, as “prior to” under broadest reasonable interpretation qualifies as “substantially at a same time”, alternatively under broadest reasonable interpretation the “same time” may be considered as the time of the process in view Varadarajan in which both forming the carbon-based layer (step (a)) and the remote plasma treatment (step (b)) occur].
Regarding claim 11 Shin in view of Varadarajan, Nishi and Ito teaches as shown above the method of claim 1,
Shin in view of Varadarajan does not explicitly teach removing the portion of the second carbon-based layer comprises etching a bottom portion of the second carbon-based layer at a faster rate than a sidewall portion ofthe second carbon-based layer.
Shin does teach anisotropically etching the carbon-based layer [paragraph 0073 “the formation of the contact spacer CSP may include conformally forming a contact spacer layer to cover the inner sidewalls of the contact holes CNH and anisotropically etching the contact spacer layer”].
It would have been obvious to one of ordinary skill in the art to modify Shin in view of Varadarajan such that “removing the portion of the second carbon-based layer comprises etching a bottom portion of the second carbon-based layer at a faster rate than a sidewall portion of the second carbon-based layer” in order to achieve the desired shape and/or pattern as specified, and/or remove excess material, without introducing defects within the surrounding material and/or elements and to allow the contact structure to electrically address the source/drain structure.
Claims 12-15 are rejected under 35 U.S.C. 103 as being unpatentable over 20200075595 A1 Shin et al here after “Shin”, and further in view of US 10832904 B2 Varadarajan hereafter “Varadarajan” and US 20170077321 A1 Ito et al hereafter “Ito” and Amano
Regarding claim 12 Shin teaches a method, comprising: forming first and second fin structures (AP1 and AP2 fig. 13B) on a substrate (100 fig. 13B);
forming n- and p-type source/drain (S/D) regions (SD1 and SD2 fig. 13B) on the first and second fin structures (AP1 and AP2 fig. 13B), respectively;
forming first and second contact openings (CNH of PR and NP regions fig. 13B) on the n- and p-type S/D regions, respectively;
depositing a first carbon-based layer (CSP of PR and NP regions fig. 13B, “SiCN” and/or “SiCON” Paragraph [0073]) with a first carbide-to-oxide etch selectivity (carbide-to-oxide etch selectivity is a material property and so SiCON and/or SiCN must necessarily have one as they are materials) in the first and second contact openings;
forming depositing a conductive layer (AC of PR and NP regions fig. 13B) in the first and second contact openings;
selectively removing a portion [Paragraph 0077, 0076, 0068] as well as anisotropically etching the first carbon-based layer [paragraph 0073 “the formation of the contact spacer CSP may include conformally forming a contact spacer layer to cover the inner sidewalls of the contact holes CNH and anisotropically etching the contact spacer layer”].
Shin does not teach performing a first remote plasma treatment on the first carbon-based layer to form a second carbon-based layer with a second carbide-to-oxide etch selectivity different from the first etch selectivity to oxide; nor
depositing a third carbon-based layer with the first carbide-to-oxide etch selectivity on the second carbon-based layer;
performing a second remote plasma treatment on the third carbon-based layer form a fourth carbon-based layer with the second carbide-to-oxide etch selectivity;
the removing portions being of the second and fourth carbon-based layers;
bottom surfaces of the fourth carbon-based layer and the conductive layer are non-coplanar with each other.
Varadarajan teaches a remote plasma treatment with radicals on the first carbon-based layer to form a second carbon-based layer. [Column 1 lines 30-47 “The method further includes flowing a source gas into a remote plasma source, generating radicals of hydrogen in the remote plasma source from the source gas… to form SiCO film”]. Therefore, the combination of Shin and Varadarajan teaches the selectively removing being of the second carbon-based layer .
Varadarajan further teaches the use of carbon-containing precursors (carrier gas) as part of the plasma treatment process [Paragraph 0017].It would have been obvious to one of ordinary skill in the art to modify the process including a carbon-based layer as taught by Shin such that it includes “a remote plasma treatment with radicals on the carbon-based layer to form a second carbon-based layer” as Varadarajan teaches to enable the formation of a high-quality carbon-based layer and reduce detrimental effects within the material [Column 3 line 55 to column 4 lines 48].
Furthermore, it would have been obvious to one of ordinary skill in the art to take the first and/or second carbon-based layer and the corresponding processes of forming as taught by Shin in view of Varadarajan and duplicate it such that there is “depositing a third carbon-based layer on the second carbon based-layer with the first carbide-to-oxide etch selectivity on the second carbon-based layer”, to increase the effective thickness of the conductive barrier while maintaining the uniformity of the material and/or decrease defects within each layer of the material, alternatively duplication of parts is prima facie type obviousness [see MPEP 2144.04 VI B], purely as evidence that composite layer and/or multi-layer conductive barrier layers was known before the effective filing date of the claimed invention, the examiner submits US 20190140066 A1 Lee et al which discloses a composite layer conductive barrier layer 151 Paragraph [0041] “The conductive barrier layer 151 may be formed of a single layer or a composite layer in which two or more layers are stacked”.
Shin, as modified using the duplication of parts rationale above, in view of Varadarajan therefore teaches performing a second remote plasma treatment on the second carbon-based layer to form a fourth carbon-based layer and the removing portions of the fourth carbon-based layer .
Ito teaches a protective layer (11 fig. 4A) comprising Silicon oxide hydrogen and carbon [Paragraph 0034] and the use of a CO.sub.2 (carbon dioxide) carrier gas during a treatment process to increase the density and/or concentration of carbon within the Silicon oxide [sufficiently disclosed paragraph 0112] to decrease the permeability of the protective layer [sufficiently disclosed Paragraph 0124].
As evidenced by Ito, the plasma treatment of Shin in view of Varadarajan would necessarily have increased the carbon density and/or concentration by using the carbon-containing precursors such that “second carbon-based layer” and “fourth carbon-based layer” has “a second density greater than the first density” and/or change the material composition (carbon-to-oxide) such that the second carbon-based layer has “a second carbide-to-oxide etch selectivity different from the first etch selectivity to oxide”.
Alternatively, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the process of Shin in view of Varadarajan to increase the concentration and/or density of carbon within the second carbon-based layer relative to the first carbon based layer as part of the plasma-treatment process to improve the result effected variable of permeability and/or the insulative proprieties of the second carbon based layer as a part of routine optimization [see MPEP 2144.05 II A]
In view of Ito the composition of the second carbon-based layer and fourth carbon based layer would necessarily be different than the first carbon-based layer and third carbon-based layer and thus have “a second carbide-to-oxide etch selectivity different from the first etch selectivity to oxide”.
Amano teaches depositing a conductive layer (674 fig. 10) and dielectric contact liners (660 fig. 10), and a silicide layer (742 and/or 744 fig. 10) wherein bottom surfaces of the dielectric contact liners and the conductive layer are non-coplanar with each other [sufficiently illustrated fig. 10 by thickness vrd].
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to combine the Shin in view of Varadarajan and Ito such that “bottom surfaces of the fourth carbon-based layer and the conductive layer are non-coplanar with each other” to create additional room space for the WFM silicide layer and/or improve contact resistance by routine optimization of the thickness of the silicide layers [See MPEP 2144.05, disclosed paragraph 0021 Amano “a thick silicide portion provides a sufficiently low contact resistance”].
Regarding claim 13 modified Shin in view of Varadarajan, Amano and Ito teaches as shown above the method of claim 12, wherein performing the first and second remote plasma treatments comprises exposing the first and third carbon-based layers to radicals of hydrogen and oxygen atoms. [This limitation is met in view of Varadarajan, “Hydrogen” column 1 lines 31 to 48 and “oxygen” sufficiently disclosed as being inherent to the process in column 3 lines 61 to column 4 lines 14]
Regarding claim 15 modified Shin in view of Varadarajan, Amano and Ito as shown above teaches the method of claim 12,
Modified Shin in view of Varadarajan does not explicitly teach wherein removing the portions of the second and fourth carbon-based layers comprises etching bottom portions of the second and fourth carbon-based layers at a faster rate than sidewall portions of the second and fourth carbon-based layers.
It would have been obvious to one of ordinary skill in the art to modify Shin in view of Varadarajan such that “selectively removing the portions of the second and fourth carbon-based layers comprises etching bottom portions of the second and fourth carbon-based layers at a faster rate than sidewall portions of the second and fourth carbon-based layers” in order to achieve the desired shape and/or pattern as specified, and/or remove excess material, without introducing defects within the surrounding material and/or elements and to allow the contact structure to electrically address the source/drain structure as illustrated in fig. 13B of Shin.
Claims 25-27 is rejected under 35 USC 103 as being obvious over Shin in view of Varadarajan, Ito, and Amano as shown in claim 26 above and in further view of US 6404025 B1 Hshieh et al hereafter “Hshieh” and evidenced by US 20130082301 A1 Onozawa et al.
Claim 25 modified Shin in view of Varadarajan, Amano and Ito teach as shown above the method of claim 12.
modified Shin in view of Varadarajan, Amano and Ito do not teach depositing a p-type capping layer on the n-type S/D region; and depositing an n-type capping layer on the p-type S/D region.
Hshieh teaches depositing a n-type capping layer (140 fig. 3D) on a p-type S/D region (130 fig. 3D).
Onozawa teaches depositing a n-type capping layer (65 fig. 26b) on a p-type S/D region (64 fig. 26b) and the benefit of in the case where a larger current flows, the voltage drop due to the current can be suppressed to be equal to or lower than the built-in potential of the pn junction between the n-type source layer 65 and the p-type base layer 64 [Disclosed paragraph 0007] and prevent a parasitic thyristor or a parasitic bipolar transistor from operating [paragraph 0008].
It would have been obvious to one of ordinary skill in the art to combine the method of Shin in view of Varadarajan, Amano and Ito in further view of the method of Hshieh such that “depositing an n-type capping layer on the p-type S/D region” occurs to control and/or suppress a voltage drop and/or prevent a parasitic thyristor and/or a parasitic bipolar transistor from operation as evidenced by Onozawa.
It would have been obvious to try, to one of ordinary skill in the art before the effective filing date of the claimed invention to modify Shin in view of Varadarajan, Amano, Ito and Hshieh such that “depositing an n-type capping layer on the p-type S/D region” occurs to control and/or suppress a voltage drop and/or prevent a parasitic thyristor and/or a parasitic bipolar transistor from operation.
Claim 26 Shin in view of Varadarajan, Amano, Ito and Hshieh teach as shown above the method of claim 25, further comprising:
etching a top portion of the p-type capping layer to form a first trench in the p-type capping layer during removal of the portion of the second carbon-based layer; and etching a top portion of the n-type capping layer to form a second trench in the n-type capping layer during removal of the portion of the fourth carbon-based layer. [met in view of fig. 3E of Hshieh wherein a top portion of the n-type caping layer and sounding insulation layers 145 is etched to form a trench for the contact structure, sufficiently illustrated fig. 3E].
Claim 27 Shin in view of Varadarajan, Amano, Ito and Hshieh as shown above teaches the method of claim 26, further comprising:
depositing a first portion of a p-type work function metal (pWFM) layer in the second trench and along sidewalls of the fourth carbon-based layer; and
depositing a second portion of the pWFM layer along sidewalls of the second carbon-based layer without depositing in the first trench.
(sufficiently disclosed in Shin paragraph [0042] “a silicide layer (not shown) may be interposed between the active contact AC and the first source/drain pattern SD1 and/or between the active contact AC and the second source/drain pattern SD2” and “The silicide layer may include metal silicide, for example, one or more of titanium silicide, tantalum silicide, tungsten silicide, nickel silicide, and cobalt silicide” in view of the modifications as shown above, the disclosed metals within the silicide constitute p-type work function metals).
Claim 28 is rejected under 35 USC 103 as being obvious over Shin in view of Varadarajan, Ito, Hshieh and Amano as shown in claim 26 above and in further view of US 20180151427 A1 Chung et al hereafter “Chung”
Claim 28 in view of Varadarajan, Amano, Ito and Hshieh teach as shown above the method of claim 26,
in view of Varadarajan, Ito and Hshieh do not explicitly teach after etching the top portion of the p-type capping layer, a portion of the p-type capping layer is converted into a first silicide layer; and wherein, after etching the top portion of the n-type capping layer, a portion of the n-type capping layer is converted into a second silicide layer different from the first silicide layer.
Chung teaches a process of forming a WFM silicide (50 fig. 6) comprising; forming a contact opening (40 fig. 3) through to a source/drain region (22 fig. 3), depositing a work function metal (46 fig. 4) and performing an anneal (52 fig. 6) to convert a portion of the work function metal (illustrated fig. 5-6) and a portion of the source/drain region (fig. 5-6) into the WFM silicide.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to combine the silicide formation process of Shin in view of Varadarajan, Ito and Hshieh in further view of the silicide formation process of Chung such that “after etching the top portion of the p-type capping layer, a portion of the p-type capping layer is converted into a first silicide layer; and wherein, after etching the top portion of the n-type capping layer, a portion of the n-type capping layer is converted into a second silicide layer different from the first silicide layer” as combining equivalents know for the same purpose is prima facie type obviousness [See MPE 2144.06] in this case its combining known processes for the same known purpose of forming silicide layers.
Claims 21-24, and 29 are rejected under 35 USC 103 as being obvious over Shin in view of Varadarajan and Amano.
Regarding claim 21 Shin teaches A method, comprising: forming a fin structure (AP1 and/or AP1 Fig. 13b) on a substrate (100 Fig. 13B);
forming a source/drain (S/D) region (SD1 and/or SD2 fig. 13B) on the fin structure
a dielectric layer (110 fig. 11B and 13B), an opening (CNH fig. 13B) in the dielectric layer and on the S/D region and etching [Paragraph 0030 “The gate capping patterns GP may include a material having an etch selectivity with respect to first and second interlayer insulating layers 110 and 120 which will be discussed below”]
depositing, in the opening and on the S/D region, a carbon-based layer (CSP fig. 13B);
depositing a conductive layer on the carbon-based layer (AC fig. 13B)
Shin does not teach etching the dielectric layer on the S/D region to form the opening;
The carbon-based layer with a first density of silicon-carbon (Si-C) bonds and a second density of silicon-oxygen bonds; Nor bottom surfaces of the carbon-based layer and the conductive layer are non-coplanar with each other
performing a plasma treatment on the carbon-based layer to increase the first density of Si C bonds and to decrease the second density of Si-O bonds; and depositing the conductive layer on the carbide layer.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to use the known method of etching as taught by Shin to form the opening in a dielectric layer as taught by Shin such that the process as taught by Shin includes “etching a dielectric layer on the S/D region to form an opening” to necessarily form the opening [CNH fig. 13B] in the shape specified.
Varadarajan teaches performing a plasma treatment for carbon-based layers. [Column 1 lines 30-47 “The method further includes flowing a source gas into a remote plasma source, generating radicals of hydrogen in the remote plasma source from the source gas… to form SiCO film”]
It would have been obvious to one of ordinary skill in the art to modify the process including a carbon-based layer as taught by Shin such that it includes “performing a plasma treatment on the carbon-based layer” to enable the formation of a high-quality carbon-based layer and reduce detrimental effects within the material.
Shin, as modified plasma treatment rationale above, in view of Varadarajan therefore teaches the carbon-based layer (Varadarajan Column 18 lines 51 - Column 19 line 53 sufficient discloses an embodiment wherein then end material is a “carbide”) comprising a first density of silicon-carbon (Si-C) bonds and a second density of silicon-oxygen (Si-O) bonds on sidewalls of the opening [Varadarajan column 3 lines 42-55 are sufficiently disclosed “some implementations, precursor molecules for depositing SiOC can include silicon-containing molecules having… silicon-carbon (Si—C) bonds, and/or silicon-oxygen (Si—O) bonds” and illustrated in fig. 4B of Varadarajan].
Varadarajan teaches Silicon carbide (comprising Si-C bonds) and Silicon oxide (comprising Si-O bonds) before the effective filing date were well known materials as shown above and known for their dielectric properties and porous properties [Column 4 lines 28-31 Varadarajan and evidenced by Paragraph 0124 ITO].
It would have been obvious to one of ordinary skill in the art before effective filing date of the claimed invention to take the process as taught by Shin in view of Varadarajan to increase the first density of silicon carbide (comprising Si-C bonds) as part of the plasma treatment process in view of Varadarajan and evidenced by Ito as part of routine optimization of the dielectric and/or porous properties of the resulting material composition [See MPEP 2144.05 II].
It would have been obvious to one of ordinary skill in the art before effective filing date of the claimed invention to take the process as taught by Shin in view of Varadarajan to decrease the second density of silicon oxide (comprising Si-O bonds) as part of the plasma treatment process in view of Varadarajan and evidenced by Ito as part of routine optimization of the dielectric and/or porous properties of the resulting material composition [See MPEP 2144.05 II].
Amano teaches depositing a conductive layer (674 fig. 10) and dielectric contact liners (660 fig. 10), and a silicide layer (742 and/or 744 fig. 10) wherein bottom surfaces of the dielectric contact liners and the conductive layer are non-coplanar with each other [sufficiently illustrated fig. 10 by thickness vrd].
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to combine the Shin in view of Varadarajan such that “bottom surfaces of the carbon-based layer and the conductive layer are non-coplanar with each other” to create additional room space for the WFM silicide layer and/or improve contact resistance by routine optimization of the thickness of the silicide layers [See MPEP 2144.05, disclosed paragraph 0021 Amano “a thick silicide portion provides a sufficiently low contact resistance”]
Regarding claim 22 modified Shin in view of Varadarajan and Amano and evidenced by Ito as shown above the method of claim 21, wherein performing the plasma treatment on the carbon-based layer comprises forming a silicon oxycarbide layer with a silicon concentration of about 25 atomic % to about 35 atomic % [in view of Varadarajan Column 10 lines 60-67 “between 15% and 45%”] , a carbon concentration of about 10 atomic % to about 40 atomic % [in view of Varadarajan Column 10 lines 60-67 “between 30% and 60%”], and an oxygen concentration of about 30 atomic % to about 55 atomic % [in view of Varadarajan Column 10 lines 60-67 “between 10% and 40%”].
Regarding claim 23 modified Shin in view of Varadarajan and Amano and evidenced by Ito teaches as shown above the method of claim 21, wherein performing the plasma treatment on the carbon-based layer comprises forming a silicon oxycarbide layer with a silicon to oxygen to carbon ratio (Si:O:C) of about 1:1:0.2 to about 1:3:1 [Sufficiently disclosed in view of Varadarajan Column 1 lines 49-60 “the ratio of silicon-oxygen bonds to silicon-carbon bonds in the SiCO film is between about 0.5:1 and about 3:1” which comes to about 1:2:0.33].
Regarding claim 24 modified Shin in view of Varadarajan and Amano and evidenced by Ito teaches as shown above the method of claim 21, wherein performing the plasma treatment comprises exposing the carbon-based layer to radicals of hydrogen and oxygen atoms. [This limitation is met in view of Varadarajan, “Hydrogen” column 1 lines 31 to 48 and “oxygen” sufficiently disclosed as being inherent to the process in column 3 lines 61 to column 4 lines 14]
Claim 29 Shin in view of Varadarajan and Amano and evidenced by Ito teach as shown above the method of claim 21, further comprising:
wherein depositing the carbon-based layer comprises depositing a silicon oxycarbide layer [Sufficiently disclosed in view of Varadarajan Column 1 lines 49-60 “the ratio of silicon-oxygen bonds to silicon-carbon bonds in the SiCO film is between about 0.5:1 and about 3:1” which comes to about 1:2:0.33 and in further view of the modification made as shown above] in contact with sidewalls of the dielectric layer in the opening.
Shin in view of Varadarajan and Amano and evidenced by Ito does not explicitly teach as modified above depositing an etch stop layer on the S/D region; and
depositing the dielectric layer on the etch stop layer,
The silicon oxycarbide layer in contact with a top surface of the etch stop layer and
Amano teaches depositing an etch stop layer (34 fig. 1) on a S/D region (22 fig. 1); and
depositing a dielectric layer (36 fig. 1) on the etch stop layer,
a contact spacer layer (44 fig. 1) in contact with the etch stop layer.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to take the method of Shin in view of Varadarajan and Amano and evidenced by Ito and further combine it with the method Amano teaches such that “an etch stop layer on the S/D region; and depositing the dielectric layer on the etch stop layer, The silicon oxycarbide layer in contact with a surface of the etch stop layer” to protect the underlying layers from subsequent and/or intermediate etching processes [See MPEP 2144.06] in this case it combining two know process for the same known purpose of forming a source/drain structure with a contact.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the method of Shin in view of Varadarajan and Amano as shown above such that “The silicon oxycarbide layer in contact with a top surface of the etch stop layer” to protect layers under the silicon oxycarbide layer from subsequent and/or intermediate etching processes and/or rearrangement of parts is prima facie type obviousness [See MPEP 2144.04].
Conclusion
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/WCT/Examiner, Art Unit 2893
/Britt Hanley/Supervisory Patent Examiner, Art Unit 2893
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