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 .
Response to Arguments
Applicant’s arguments with respect to claims presented have been considered but are moot because the new ground of rejection does not rely on any reference applied in the prior rejection of record for any teaching or matter specifically challenged in the argument.
Claim Rejections - 35 USC § 102
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 the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action:
A person shall be entitled to a patent unless –
(a)(1) the claimed invention was patented, described in a printed publication, or in public use, on sale, or otherwise available to the public before the effective filing date of the claimed invention.
(a)(2) the claimed invention was described in a patent issued under section 151, or in an application for patent published or deemed published under section 122(b), in which the patent or application, as the case may be, names another inventor and was effectively filed before the effective filing date of the claimed invention.
Claims 1,5 and 9 are rejected under 35 U.S.C. 102(a)(1)/(a)(2) as being anticipated by Balakrishnan et al. (US9627381B1).
Regarding claim 1, Fig.8 of Balakrishnan teaches a method of forming a strain relaxed buffer (SRB) layer 104 (col.3, line 18) on a substrate 102 (col.3, line 22), comprising:
epitaxially depositing a first silicon germanium layer 104 (col.3, line 18) over the substrate 102, wherein the first silicon germanium layer 104 has a first surface that contacts a frontside surface (see annotated Fig.8) of the substrate 102 and a second surface (see annotated Fig.8) opposite the first surface, wherein the first silicon germanium layer 104 has a first thickness (see annotated Fig.8) and a germanium concentration gradient that increases from the first surface to the second surface (col.3, lines 29-33, wherein Ge concentration of the SRB layer 104 can be gradually increased as the layer is grown (linearly) (rather than incrementally in different layers) until the top portion 106 of the SRB layer 104 is formed having a target Ge concentration); and
epitaxially depositing a silicon germanium capping layer 106 (col.3, line 32) on the first silicon germanium layer 104, wherein the silicon qermanium cappinq layer 106 has a backside surface (see annotated Fig.8) that contacts the second surface of the first silicon qermanium layer 104 and a frontside surface opposite the backside surface of the silicon germanium capping layer 106,
wherein the silicon germanium capping layer 106 has a second thickness (see annotated Fig.8) and a substantially uniform germanium concentration that is equal to, substantially equal to, or greater than a maximum germanium concentration of the germanium concentration gradient (col.3, line 29, wherein portion 106 has a target Ge concentration which is the maximum Ge concentration), and
wherein the first thickness is greater than the second thickness (see annotated Fig.8).
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Regarding claim 5, Balakrishnan further teaches the method of claim 1, wherein the substrate comprises silicon 102 (col.3, line 22).
Regarding claim 9, Balakrishnan further teaches the method of claim 1, wherein epitaxially depositing the first silicon germanium layer 104 (col.3, line 18) over the substrate 102 (col.3, line 22) comprises increasing a flow rate of a germanium source gas to form the germanium concentration gradient that increases from the first surface to the second surface (col.3, lines 29-33, wherein Ge concentration of the SRB layer 104 can be gradually increased as the layer is grown (linearly) (rather than incrementally in different layers) until the top portion 106 of the SRB layer 104 is formed having a target Ge concentration).
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.
Claims 2-4 are rejected under 35 U.S.C. 103 as being unpatentable over Balakrishnan et al. (US9627381B1).
Regarding claim 2, Balakrishnan further teaches the method of claim 1, wherein the first thickness is in a range from about 2000 nm to about 2500 nm and the germanium concentration gradient increases from 0 at% adjacent to an interface with the substrate to the maximum germanium concentration in a range from about 10 at% to about 15 at% (col.3, lines 29-33, wherein Ge concentration of the SRB layer 104 can be gradually increased as the layer is grown (linearly) (rather than incrementally in different layers) until the top portion 106 of the SRB layer 104 is formed having a target Ge concentration).
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); In re Woodruff, 919 F.2d 1575, 16 USPQ2d 1934 (Fed. Cir. 1990). See MPEP 2144.05(I).
Regarding claim 3, Balakrishnan further teaches the method of claim 2, wherein the second thickness is in a range from about 1000 nm to about 1200 nm and the substantially uniform germanium concentration is substantially equal to, equal to, or greater than the maximum germanium concentration of the first silicon germanium layer (col.3, lines 39-42, wherein the top portion 106 of the SRB layer 104 preferably has a thickness of from about 1 micrometer (μm) to about 3 μm, and ranges therebetween and col.3, line 29, wherein portion 106 has a target Ge concentration which is the maximum Ge concentration).
Regarding claim 4, Balakrishnan further teaches the method of claim 1, wherein the germanium concentration gradient increases from a first germanium concentration in a range from about 0 at% to about 2 at% of germanium to a second germanium concentration in range from about 10 at% to about 15 at% (col.3, lines 29-33, wherein Ge concentration of the SRB layer 104 can be gradually increased as the layer is grown (linearly) (rather than incrementally in different layers) until the top portion 106 of the SRB layer 104 is formed having a target Ge concentration and col.3, lines 34-37, wherein the top portion 106 of the (SiGe) SRB layer 104 has a target Ge concentration of from about 15 atomic percent (at. %) to about 30 at. %, and ranges therebetween).
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); In re Woodruff, 919 F.2d 1575, 16 USPQ2d 1934 (Fed. Cir. 1990). See MPEP 2144.05(I).
Claims 6-8 are rejected under 35 U.S.C. 103 as being unpatentable over Balakrishnan et al. (US9627381B1) in view of Cui et al. (US20210371774A1).
Regarding claim 6, Balakrishnan does not teach wherein the method of claim 1, further comprising polishing the silicon germanium capping layer to reduce the second thickness to a third thickness.
Fig.2D of Cui teaches wherein a cleaning composition for cleaning a surface of a substrate comprising silicon germanium after a chemical mechanical polishing process is provided; wherein Chemical mechanical polishing (CMP) is necessary to reduce roughness of the Ge-containing regions and to remove the excess amount of Ge or SiGe, reaching final thickness.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to include the chemical mechanical polishing process of Cui in the teachings of HUANG, as modified by Balakrishnan; in order to provide a smooth and defect free surface improves the quality of devices subsequently formed thereon (Cui, [para.0011]).
Regarding claim 7, Cui further teaches the method of claim 1, wherein after polishing the silicon germanium capping layer, the silicon germanium capping layer has a top surface having a root mean square (RMS) roughness of 5 A or less. Cui discloses in paragraph 42 wherein the surface roughness of the first fins 210 and second fins 220 expressed by root mean square (rms) is less than 20 nm, less than 10 nm, less than 5 nm, less than 3 nm, less than about 1 nm, less than 0.5 nm or less than 0.2 nm.
Regarding claim 8, Fig.3 of Cui teaches the method of claim 6, further comprising exposing the silicon germanium capping layer to a wet clean process after polishing the silicon germanium capping layer (para.0012, wherein the substrate surface is cleaned using an aqueous cleaning composition to remove residues).
Claim 20 is rejected under 35 U.S.C. 103 as being unpatentable over HUANG et al. (US20150079803A1) in view of Balakrishnan et al. (US9627381B1) and in further view of Cui et al. (US20210371774A1).
Regarding claim 20, Fig.2 of HUANG teaches a method of forming a semiconductor device,
comprising:
epitaxially depositing a strain relaxed buffer layer 220 (para.0043) over a substrate 210 (para.0038), in a first processing chamber 100 (para.0024), comprising: epitaxially depositing a first silicon germanium layer 220 (para.0043) over the substrate 210, wherein the first silicon germanium layer 220 has a first thickness (see annotated Fig.2); and
epitaxially depositing a silicon germanium capping layer 230 (para.0051) on the first silicon germanium layer 220,
wherein the silicon qermanium cappinq layer 230 has a backside surface (see annotated Fig.2) that contacts the second surface of the first silicon qermanium layer 220 and a frontside surface (see annotated Fig.2) opposite the backside surface of the silicon germanium capping layer 230,
wherein the silicon germanium capping layer 230 has a second thickness (see annotated Fig.2), and
wherein the first thickness is greater than the second thickness;
transferring the substrate 210 to a second processing chamber positioned ex-situ to an integrated processing system (para.0011);
transferring the substrate 210 to a third processing chamber positioned ex-situ to the integrated processing system (para.0011);
transferring the substrate 210 to a first processing chamber of the integrated processing system;
exposing the substrate 210 (para.0040) to a dry clean process in the first processing chamber of the integrated processing system using a remote plasma source (para.0041) to generate an etchant species (para.0041) from a fluorine-containing precursor (para.0040) and a hydrogen-containing precursor (para.0041);
transferring the substrate 210 to a second processing chamber of the integrated processing system (para.0011); and
epitaxially depositing a superlattice structure (para.0020) on the strain relaxed buffer layer in the second processing chamber of the integrated processing system, wherein the superlattice structure contacts the frontside surface of the silicon qermanium cappinq layer (para.0070, wherein additional thin silicon capping layers in SiGe(65%) and the formation of a superlattice lowers the surface roughness further down).
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HUANG does not teach a germanium concentration gradient that increases from a first surface to a second surface of the first silicon germanium layer and a substantially uniform germanium concentration that is equal to, substantially equal to, or greater than a maximum germanium concentration of the germanium concentration gradient.
Fig.8 of Balakrishnan teaches a (SiGe) SRB layer 104 having been formed on the substrate that includes a top portion 106 of the SRB layer 104 that is relaxed and wherein Ge concentration of the SRB layer 104 can be gradually increased as the layer is grown (linearly) (rather than incrementally in different layers) until the top portion 106 of the SRB layer 104 is formed having a target Ge concentration and wherein portion 106 has a target Ge concentration which is the maximum Ge concentration (col.3, lines 29-33).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to include Balakrishnan’s germanium concentration, that is gradually increased as the layer is grown (linearly) until the top portion 106 of the SRB layer 104 is formed having a target Ge concentration, the teachings of HUANG because the top of the SRB layer will be relaxed in that any degree of lattice mismatch (from Si to SiGe) is compensated by the gradual increase in Ge concentration throughout the SRB and a relaxed active layer is beneficial for enhanced electron and hole mobility (Balakrishnan, [col.3, lines 9-13]).
However, HUANG, as modified by Balakrishnan, does not expressly disclose wherein polishing the silicon germanium capping layer to reduce the second thickness to a third thickness in the second processing chamber; exposing the silicon germanium capping layer to a wet clean process in the third processing chamber after polishing the silicon germanium capping layer.
Fig.2D of Cui teaches wherein a cleaning composition for cleaning a surface of a substrate comprising silicon germanium after a chemical mechanical polishing process is provided; wherein Chemical mechanical polishing (CMP) is necessary to reduce roughness of the Ge-containing regions and to remove the excess amount of Ge or SiGe, reaching final thickness and wherein the substrate surface is cleaned using an aqueous cleaning composition to remove residues (para.0010, 0012).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to include the chemical mechanical polishing process and aqueous cleaning composition of Cui in the teachings of HUANG, as modified by Balakrishnan; in order to provide a smooth and defect free surface improves the quality of devices subsequently formed thereon (Cui, [para.0011]).
Claim 21 is rejected under 35 U.S.C. 103 as being unpatentable over Balakrishnan et al. (US9627381B1) in view of Lee et al. (US20230141135A1).
Regarding claim 21, Balakrishnan does not disclose epitaxially depositing a superlattice structure on the silicon germanium capping layer, the superlattice structure comprising:
a silicon germanium spacer layer; and
a silicon channel layer, wherein the silicon germanium spacer layer and the silicon channel layer are disposed in an alternating stacked arrangement and the silicon germanium spacer layer contacts the frontside surface of the silicon germanium capping layer.
Fig.2 of Lee teaches wherein multi-stack 120 may be on the whole (e.g., may completely cover the entire) surface of the SRB layer 110. The multi-stack 120 may have a superlattice structure including a plurality of silicon (Si) layers 121 and a plurality of silicon germanium (SiGe) layers 122, which are alternately stacked with each other; wherein each of the plurality of silicon (Si) layers 121 and the plurality of silicon germanium (SiGe) layers 122 included in the multi-stack 120 may be an epitaxial growth layer; and wherein silicon germanium spacer layer is SRB layer 110 (para.0029-0030).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to include the superlattice structure and SRB layer 110 of Lee in the teachings of Balakrishnan in order to further improve the performance of the device.
Conclusion
Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). 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 VINCENT KIPKEMOI RONO whose telephone number is (571)270-5977. The examiner can normally be reached Mon-Fri, 8am-5pm.
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If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Matthew Landau can be reached at (571)272-1731. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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VINCENT KIPKEMOI. RONO
Examiner
Art Unit 2891
/V.K.R./Examiner, Art Unit 2891
/MATTHEW C LANDAU/Supervisory Patent Examiner, Art Unit 2891
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