DETAILED ACTION
This office action is in response to the amendment filed 5/15/2026.
Currently, claims 1-2, 4-8, 10-14, 16-17, 19 and 21-25 are pending. Of these, claims 5 and 24 remain withdrawn from consideration.
Claim Objections
Claims 7 and 23 are objected to because of the following informalities: In claim 7, line 2, “phase” is misspelled as “phrase”. In claim 23, line 2, the word “a” is missing preceding “portion”.
Appropriate correction is required.
Claim Rejections - 35 USC § 112
The following is a quotation of 35 U.S.C. 112(b):
(b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention.
The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph:
The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention.
Claims 14, 16-17, 19 and 23 are rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention.
Claim 14 recites the limitation “wherein the plurality of metal gates comprises a trench” in lines 2-3. This limitation is unclear in light of the disclosure as originally filed, which does not show any of the plurality of gates comprising a trench. For purposes of examination, the limitation is understood to refer to the trench that is the space between the metal gates.
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 1-2, 4, 6, 8, 12-14, 16-17, 19, 21-23 and 25 are rejected under 35 U.S.C. 103 as being unpatentable over Hung in view of Garg et al. (US 7,311,946, cited in IDS) and Ting.
Pertaining to claim 1, Hung shows, with reference to FIG. 17, a device, comprising:
a semiconductor substrate (100);
a trench (178 in region A, see FIG. 16) in the device and above the semiconductor substrate;
an epitaxial region (158) in the semiconductor substrate and below the trench (either a region of an epitaxial silicon substrate (col. 3, lines 31-33) or an epitaxial region formed on the substrate (col. 4, lines 57-63));
a silicide layer (274) at a bottom of the trench;
a titanium nitride layer (e.g. 284a) in the trench and over the silicide layer (col. 8, lines 17-19); and
a metal plug (284b) in the trench and over the titanium nitride layer.
Pertaining to claim 8, Hung shows a device, comprising:
a substrate (100) comprising an epitaxial region (158);
a plurality of metal gates (150), on the substrate, defining a trench (178 in region A, see FIG. 16) therebetween;
a silicide layer (274) in the trench;
a metal adhesion layer (e.g. 284a) in the trench and over the silicide layer; and
a metal plug (284b) in the trench and over the metal adhesion layer.
Pertaining to claim 14, Hung shows a device, comprising:
a plurality of metal gates (150) on a substrate (100), wherein the plurality of metal gates comprises a trench (178 in region A, see FIG. 16);
a silicide layer (274) in the trench;
a metal adhesion layer (e.g. 284a), comprising nitrogen ions (col. 8, lines 17-19), in the trench and over the silicide layer; and
a metal plug (284b) in the trench and over the metal adhesion layer.
Hung fails to anticipate the claimed invention in not explicitly showing the titanium nitride layer/metal adhesion layer comprises a (111) phase and an other phase, wherein the (111) phase is greater relative to the other phase. Also, Hung fails to show the silicide layer is above a topmost surface of the substrate, and that a seed layer is in the trench and over the titanium nitride/metal adhesion layer.
However, Garg teaches in col. 7, lines 43-66 and col. 9, line 49 – col. 10, line 16 that, for a similar structure using a TiN barrier layer, the (111) phase is 95% or greater. Inherently, this leaves up to 5% of another orientation.
It would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to employ the (111) preferred orientation TiN taught by Garg for the TiN barrier layer of Hung, with the motivation that the (111) orientation leads to improved adhesion between the barrier layer and the metal fill and promotes a (111) orientation of the metal fill which may lead to improved electrical characteristics (col. 12, lines 15-28).
Garg further teaches a seed layer formed on the barrier layer (col. 12, lines 32-34).
It would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to form a seed layer on the barrier layer of Hung, as taught by Garg, with the motivation that the seed layer facilitates the further deposition of the desired metal by numerous deposition techniques such as electrochemical plating, electroless plating, PVD, CVD, or ALD (col. 2, lines 3-9).
Meanwhile, Ting teaches in para. [0009] that a metal silicide formed on impurity regions of a transistor structure is higher than the substrate surface.
It would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to modify Hung such that the silicide layer is above the top surface of the substrate, as taught by Ting, with the motivation that such an arrangement mitigates possible counteracting effects of the metal silicide layer and enhances the device performance (para. [0009]).
Pertaining to claim 2, Hung shows a first metal gate (150) and a second metal gate (150), wherein the trench is between the first metal gate and the second metal gate (FIG. 16).
Pertaining to claim 4, Hung shows the semiconductor substrate includes a shallow trench isolation (106).
Pertaining to claim 6, it would have been obvious to one of ordinary skill in the art, before the effective filing date, for the thickness of the titanium nitride layer to be 1 to 3 nanometers, since it has been held that discovering an optimum value of a result effective variable involves only routine skill in the art. In re Boesch, 617 F.2d 272, 205 USPQ 215 (CCPA 1980). The thickness of such barrier layers is known to affect the barrier properties and the resistivity of the interconnect structure.
Pertaining to claim 12, Hung shows a plurality of insulating caps (157) on the plurality of metal gates, wherein the plurality of insulating gaps and the plurality of metal gates form the trench.
Pertaining to claim 13, Hung shows a plurality of gate spacers (153) on each side of the trench.
Pertaining to claim 16, Hung shows the metal adhesion layer may be a titanium nitride layer (col. 8, lines 17-19).
Pertaining to claim 17, Hung shows an epitaxial region (158) between the plurality of metal gates.
Pertaining to claim 19, Garg teaches the seed layer may be a different material than at least one of the metal plug or the metal adhesion layer (col. 12, lines 32-34; col. 6, line 63 – col. 7, line 1; col. 9, line 49).
Pertaining to claims 21-23, applying the teaching of Ting to Hung results in the silicide occupying a portion of the trench at the bottom, leaving portions of the sidewalls of the trench exposed upon deposition of Hung’s metal adhesion layer.
Pertaining to claim 25, Hung shows the plurality of insulating caps are in contact with each of the plurality of gate spacers (FIG. 17).
Claims 10-11 are rejected under 35 U.S.C. 103 as being unpatentable over Hung in view of Garg and Ting as applied to claims 1 and 8 above, and further in view of Yang et al. (US 6,911,391, cited in IDS).
Hung in view of Garg and Ting, fails to teach a titanium silicon nitride layer between the silicide layer and the adhesion layer, and on a side of the metal gates.
However, Yang teaches in column 12, line 63 – column 13, line 3 and FIG. 6 that, for a similar device having a metal plug on a titanium nitride adhesion layer, a titanium silicon nitride layer 860 is first formed over the bottom and sidewalls of the trench. The titanium nitride layer 861 is then deposited over the titanium silicon nitride layer 860.
It would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to form a titanium silicon nitride before forming the titanium nitride layer of Hung in view of Garg and Ting, with the motivation that the titanium silicon nitride acts to improve adhesion (column 3, lines 33-41). Because the trench sidewalls of Hung in view of Garg and Ting are defined by the metal gates, applying the teaching of Yang to Hung results in the TiSiN being formed on the sides of the metal gates.
Allowable Subject Matter
Claim 7 contains allowable subject matter as discussed in the office action dated 2/17/2026.
Response to Arguments
Applicant's arguments filed 5/15/2026 have been fully considered but they are not persuasive.
Applicant argues that “HUNG, TAKEWAKA, GARG, and TING do not disclose at least: ‘a titanium nitride layer in the trench and over the silicide layer, the titanium nitride layer comprising a (111) phase and an other phase, wherein the (111) phase is greater relative to the other phase’”. Applicant states that “Because TAKEWAKA and GARG do not disclose the presence of multiple phases or any relative phase composition, and do not disclose that a (111) phase is present in a greater amount than another phase, they fail to teach or suggest the claimed limitations.” The arguments are based on a scenario in which there is only (111) phase present.
In response, Garg does not teach the scenario in which only (111) phase is present. Rather, Garg teaches that the (111) phase is as low as 95% (col. 7, lines 44-49). There is then inherently another phase present, up to 5%. Thus, Garg indeed teaches the presence of multiple phases, where a (111) phase is present in a greater amount than another phase.
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 DANIEL M LUKE whose telephone number is (571)270-1569. The examiner can normally be reached Monday-Friday, 9am-5pm, EST.
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/DANIEL LUKE/Primary Examiner, Art Unit 2896
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