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 .
Claim Rejections - 35 USC § 102
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.
Claim(s) 21-23, 25 and 27-29 is/are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Xie et al. (PG Pub. No. US 2021/0265348 A1).
Regarding claim 21, Xie teaches a method comprising:
growing a first epitaxial source/drain region (¶ 0049: 302) adjacent to a first semiconductor nanostructure (¶ 0035, fig. 3: 302 grown adjacent to stack of lower nanostructures 108);
forming a first source/drain contact (¶ 0055: sacrificial material 304; since 304 is subsequently replaced with contact structure 902/silicide, and therefore meets the broadest reasonable interpretation of a sacrificial source/drain contact) adjacent to the first epitaxial source/drain region (fig. 4: 304 formed adjacent to 302);
after forming the first source/drain contact, forming an isolation dielectric (¶ 0059: 402) on the first source/drain contact and on the first epitaxial source/drain region (fig. 9: 304 at least indirectly formed on 304 and 302);
growing a second epitaxial source/drain region (¶ 0060: 502) on the isolation dielectric and adjacent to a second semiconductor nanostructure (¶¶ 0035, fig. 5: 502 formed at least indirectly on 402 and adjacent to upper stack of nanostructures 108), the second semiconductor nanostructure stacked over the first semiconductor nanostructure (fig. 9 among others: upper nanostructures 108 stacks over lower nanostructures 108), the isolation dielectric separating the second epitaxial source/drain region from the first epitaxial source/drain region (fig. 9: 402 separates 502 from 302); and
forming a second source/drain contact (¶¶ 0063, 0079: sacrificial contact 504, non-illustrated silicide and/or 904) adjacent to the second epitaxial source/drain region (figs. 5, 9: 504 and 904 each formed adjacent to 502), the isolation dielectric separating the second source/drain contact from the first source/drain contact (fig. 5: 402 separates 504 from 304).
Regarding claim 22, Xie teaches the method of claim 21, wherein the first source/drain contact and the second source/drain contact are formed of the same contact material (¶¶ 0055, 0064: in at least one embodiment, 304 and 504 formed of same material).
Regarding claim 23, Xie teaches the method of claim 21, wherein the first source/drain contact and the second source/drain contact are formed of different contact materials (¶¶ 0055, 0064: in at least one embodiment, 304 and 504 formed of different materials).
Regarding claim 25, Xie teaches the method of claim 21, wherein the first epitaxial source/drain region and the first source/drain contact are each formed in a recess adjacent to the first semiconductor nanostructure (¶ 0079 & fig. 9: 302, 304 formed in recess adjacent to lower nanostructure stack 108), and the first source/drain contact occupies more of the recess than the first epitaxial source/drain region (fig. 5: 304 occupies more of the recess than 302).
Regarding claim 27, Xie teaches the method of claim 21, wherein forming the first source/drain contact comprises:
depositing a conductive material (¶ 0055: in at least one embodiment, 304 formed with conductive dielectric material); and
recessing the conductive material using an etch-back process (¶ 0056 & figs. 3-4: recessed below a below spacer 202 by a wet or dry etch-back process).
Regarding claim 28, Xie teaches the method of claim 21, wherein forming the isolation dielectric comprises:
depositing a dielectric material (¶ 0055: 304); and
recessing the dielectric material using an isotropic etch (¶ 0056: 304 recessed with wet etch, which is inherently isotropic).
Regarding claim 29, Xie teaches the he method of claim 21, wherein growing the first epitaxial source/drain region comprises stopping growth of the first epitaxial source/drain region before the first epitaxial source/drain region merges with adjoining epitaxial growth (Xie, fig. 3: 302 growth stopped before vertically or laterally merging).
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.
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.
Claim 24 is rejected under 35 U.S.C. 103 as being unpatentable over Xie as applied to claim 21 above, and further in view of Chu et al. (PG Pub. No. US 2022/0069135 A1).
Regarding claim 24, Xie teaches the method of claim 21, comprising a first epitaxial source/drain region (Xie, 302).
Xie does not teach wherein the first epitaxial source/drain region has a thickness in a range of 1 nm to 5 nm measured in a direction extending between a sidewall of the first semiconductor nanostructure and a sidewall of the first source/drain contact.
Chu teaches a method including forming a first epitaxial source/drain region (¶ 0028: 236, similar to 302 of Xie), wherein the first epitaxial source/drain region has a thickness in a range of 4 nm to 6 nm measured in a direction extending between a sidewall of a first semiconductor nanostructure and a sidewall of a first source/drain contact (¶ 0028, fig. 13A: 236 has a thickness of 4 nm to 6 nm along the x direction, between nanostructures 208 and source/drain contacts 238).
It would have been obvious to one of ordinary skill in the art at the time the invention was filed to configure the first epitaxial source/drain region of Xie with the thickness of Chu, as a means to reduce resistance (Chu, ¶¶ 0004, 0030).
Furthermore, it has been held that 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). In the instant case, the claimed epitaxial source/drain thickness range of 4 nm to 6 nm overlaps the range disclosed by Chu.
Claims 26 is rejected under 35 U.S.C. 103 as being unpatentable over Xie as applied to claim 21 above, and further in view of Ma.
Regarding claim 26, Xie teaches the method of claim 21, comprising growing a first epitaxial source/drain region (302).
Xie does not teach the method further comprising:
forming a stop material prior to growing the first epitaxial source/drain region, wherein the first epitaxial source/drain region and the first source/drain contact are each formed on the stop material.
Ma teaches a method including:
forming a stop material (¶¶ 0020, 0039: undoped layer 232) in a recess (fig. 4); and
growing a first epitaxial source/drain region (234) on the stop material (fig. 4).
It would have been obvious to one of ordinary skill in the art at the time the invention was filed to configure the method of Xie with the stop material of Ma, as a means to provide lattice mismatch with source/drain materials (Ma, ¶ 0048), improving performance of the source/drain regions (Ma, ¶ 0012).
Furthermore, the combination of Xie and Ma would implicitly include forming the first source/drain contact of Xie at least indirectly on the stop material of Ma.
Allowable Subject Matter
Claims 15-20 and 30-34 are allowed.
The following is an examiner’s statement of reasons for allowance: The prior art fails to teach or clearly suggest the limitations stating:
“the first source/drain contact and the first epitaxial source/drain region each directly contact a top surface of the stop material” as recited in claim 15, and
“the isolation dielectric directly contacts and extends continually across an upper surface of the first epitaxial source/drain region and a lower surface of the second epitaxial source/drain region” as recited in claim 30.
Xie et al. (US 2021/0265348 A1) teaches a method including forming a first source/drain contact (902) and a first epitaxial source/drain region (302), but does not teach forming a stop material in a nanostructure recess.
Xie et al. (US 2023/0065715 A1, hereinafter referenced as ‘Xi-715’) teaches a method including forming a nanostructure recess (fig. 6) and forming a source/drain contact (1710) and a first epitaxial source/drain region (710) each directly contacting a top surface of a stop material (fig. 17: 1710 and 710 each directly contact a top surface of layer 210). However, Xie-715 fails to teach forming the stop material in the nanostructure recess.
Therefore, neither Xie not X-715, alone or in combination, teach the features of claim 15.
Furthermore, Frougier (US 10,192,867 B1) teaches an isolation dielectric (810) a first source/drain (S1/D1) and a second source/drain (S2/D2), but fails to teach the isolation dielectric directly contacts and extends continually across upper surfaces of the first and second epitaxial source/drain regions.
Frougier et al. (US 2020/0287046 A1) teaches an isolation dielectric (402) directly contacting and extending continually across an upper surface of a first source/drain region (304), but fails to teach the isolation dielectric directly contacting and extending continually across a lower surface of a second source/drain region, as required by claim 30.
Claims 16-20 and 31-34 depend on claims 15 and 30, and are allowed for implicitly including the allowable subject matter above.
In light of these limitations in the claims (see the Applicant’s fig. 17A & ¶ 0067), the previously applied references do not anticipate or obviate the claimed methods as in the context of the claims.
Any comments considered necessary by applicant must be submitted no later than the payment of the issue fee and, to avoid processing delays, should preferably accompany the issue fee. Such submissions should be clearly labeled “Comments on Statement of Reasons for Allowance.”
Response to Arguments
Applicant’s arguments, see pages 7 and 9, filed 2/16/2026, with respect to the 35 USC § 102 and 35 USC § 103 rejections of claims 15-20 and 30-34 have been fully considered and are persuasive. Accordingly, these rejections are withdrawn.
Applicant's arguments with respect to the 35 USC § 102 and 35 USC § 103 rejections of claims 21-29 have been fully 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.
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 BRIAN TURNER whose telephone number is (571)270-5411. The examiner can normally be reached M-F 8am-5pm.
Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice.
If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Eva Montalvo can be reached at 571-270-3829. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
Information regarding the status of published or unpublished applications may be obtained from Patent Center. Unpublished application information in Patent Center is available to registered users. To file and manage patent submissions in Patent Center, visit: https://patentcenter.uspto.gov. Visit https://www.uspto.gov/patents/apply/patent-center for more information about Patent Center and https://www.uspto.gov/patents/docx for information about filing in DOCX format. For additional questions, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000.
/BRIAN TURNER/Examiner, Art Unit 2818