DETAILED ACTION
This office action is in response to the RCE filed 1/26/2026.
Currently, claims 1-2, 4-8, 10-14, 16-17, 19 and 21-25 are pending. Of these, claims 5 and new claim 24 are withdrawn from consideration.
Election/Restrictions
Newly submitted claim 24 is directed to an invention that is independent or distinct from the invention originally claimed for the following reasons:
This application contains claims directed to the following patentably distinct species:
A device in which a TiSiN layer is formed in the trench, over which the metal adhesion layer is formed (e.g. claim 10).
A device in which the TiSiN layer is omitted, such that the gate spacers directly contact the metal adhesion layer (e.g. claim 24).
The species are independent or distinct because, when the TiSiN layer is present, it prevents contact between the gate spacers and the metal adhesion layer. In addition, these species are not obvious variants of each other based on the current record.
Since applicant has received an action on the merits for the originally presented invention, this invention has been constructively elected by original presentation for prosecution on the merits. Accordingly, claim 24 is withdrawn from consideration as being directed to a non-elected invention. See 37 CFR 1.142(b) and MPEP § 821.03.
To preserve a right to petition, the reply to this action must distinctly and specifically point out supposed errors in the restriction requirement. Otherwise, the election shall be treated as a final election without traverse. Traversal must be timely. Failure to timely traverse the requirement will result in the loss of right to petition under 37 CFR 1.144. If claims are subsequently added, applicant must indicate which of the subsequently added claims are readable upon the elected invention.
Should applicant traverse on the ground that the inventions are not patentably distinct, applicant should submit evidence or identify such evidence now of record showing the inventions to be obvious variants or clearly admit on the record that this is the case. In either instance, if the examiner finds one of the inventions unpatentable over the prior art, the evidence or admission may be used in a rejection under 35 U.S.C. 103 or pre-AIA 35 U.S.C. 103(a) of the other invention.
Claim Objections
Claims 21-23 are objected to because of the following informalities: The word “the” preceding “claim” is erroneous.
Furthermore, although withdrawn from consideration, claim 24 lists “the silicide” layer twice, which appears to be erroneous.
Appropriate correction is required.
Claim Rejections - 35 USC § 112
The following is a quotation of the first paragraph of 35 U.S.C. 112(a):
(a) IN GENERAL.—The specification shall contain a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the same, and shall set forth the best mode contemplated by the inventor or joint inventor of carrying out the invention.
The following is a quotation of the first paragraph of pre-AIA 35 U.S.C. 112:
The specification shall contain a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the same, and shall set forth the best mode contemplated by the inventor of carrying out his invention.
Claims 21-23 are rejected under 35 U.S.C. 112(a) or 35 U.S.C. 112 (pre-AIA ), first paragraph, as failing to comply with the written description requirement. The claim(s) contains subject matter which was not described in the specification in such a way as to reasonably convey to one skilled in the relevant art that the inventor or a joint inventor, or for applications subject to pre-AIA 35 U.S.C. 112, the inventor(s), at the time the application was filed, had possession of the claimed invention.
Each of claims 21-23 recites that the titanium nitride layer/metal adhesion layer is on an entire height of a sidewall of the trench. The disclosure does not support such subject matter. See FIG. 2A and 2H. The independent claims state that the silicide layer (208) is in the trench. As seen in FIG. 2A and 2H, the silicide occupies a portion of the space along the height of the sidewall of the trench. Thus, the limitation “the titanium nitride layer (or metal adhesion layer) is on an entire height of a sidewall of the trench” is not disclosed and is considered to be new matter.
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 21-23 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 “a plurality of metal gates, on a substrate, comprising a trench” in line 2. It is unclear whether the trench is associated with the metal gates or the substrate. However, as disclosed, neither the metal gates nor the substrate comprises a trench. For purposes of examination, the limitation is understood to refer to the trench that is the space between the metal gates.
Regarding claims 21-23, it is not clear how the titanium nitride layer/metal adhesion layer could be on an entire height of the sidewall of the trench when, at the same time, the silicide layer is at the bottom of the trench, as claimed in the independent claims on which these claims depend. In other words, the limitations of claims 21-23 appear to contradict the limitations from the independent claims on which they depend. For purposes of examination, the limitation is understood mean that the titanium nitride layer/metal adhesion layer is on an entire height of the trench except for the portion occupied by the silicide.
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, 6-7, 14, 16-17, 19, 21 and 23 are rejected under 35 U.S.C. 103 as being unpatentable over Hung et al. (US 9,905,464) in view of Takewaka et al. (US 2004/0087137), Ting et al. (US 2009/0166625) and Lee (US 5,567,987).
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 14, Hung shows a device, comprising:
a plurality of metal gates (150), on a substrate (100), comprising a trench (178 in region A, see FIG. 16) of the device;
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 having a (111) dominant phase/more (111) than (200). 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, Takewaka teaches in para. [0030] that, for a similar structure using a TiN barrier layer, a (111) orientation is set for the TiN material.
It would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to employ a (111)-oriented TiN material for the TiN barrier layer of Hung, as taught by Takewaka, with the motivation that the (111) orientation reduces stress in the TiN layer, thereby improving adhesiveness (para. [0030], [0033]).
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]).
And finally, Lee teaches in FIG. 4 that, for a similar contact structure, a nucleation layer 36, equivalent to the claimed seed layer, is formed over the titanium nitride layer 35 so that a fill metal 37 may be formed in the opening.
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 to include a nucleation layer over the titanium nitride/metal adhesion layer, as taught by Lee, with the motivation that the nucleation layer promotes uniform formation of the subsequently formed fill metal (col. 7, lines 42-44).
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 effect the barrier properties and the resistivity of the interconnect structure.
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, the metal plug and the metal adhesion layer are different materials, and thus the seed layer must be a different material from at least one of them.
Pertaining to claims 21 and 23, Hung shows the titanium nitride layer/adhesion layer is on an entire height of the trench (FIG. 17).
Claims 8-9, 12-13, 22 and 25 are rejected under 35 U.S.C. 103 as being unpatentable over Hung in view of Takewaka and Ting.
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.
Hung fails to anticipate the claimed invention in not explicitly showing the metal adhesion layer being composed more of a (111) dominant phase than a (200) phase. Also, Hung fails to show the silicide layer is above a topmost surface of the substrate.
However, Takewaka teaches in para. [0030] that, for a similar structure using a TiN barrier layer, a (111) orientation is set for the TiN material.
It would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to employ a (111)-oriented TiN material for the TiN barrier layer of Hung, as taught by Takewaka, with the motivation that the (111) orientation reduces stress in the TiN layer, thereby improving adhesiveness (para. [0030], [0033]).
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 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 22, Hung shows the adhesion layer is on an entire height of the trench (FIG. 17).
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 1-2, 4, 6, 8, 12-14, 16-19, 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.
As discussed in the rejections above, Hung shows the devices of claims 1, 8 and 14 except for the titanium nitride layer/metal adhesion layer having a (111) dominant phase/more (111) than (200), and the silicide being above a topmost surface of the substrate.
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 orientation is substantially (111).
It would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to employ a (111)-oriented TiN material for the TiN barrier layer of Hung, as taught by Garg, 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).
Meanwhile, Ting teaches the silicide being above a topmost surface of the substrate, as discussed in the rejection above.
As it pertains to claims 2, 4, 12-13, 16-17, and 21-23, Hung shows these limitations as discussed in the rejections above.
Pertaining to claim 3, Garg teaches the (111) dominant phase increases adhesion between the titanium nitride layer and the metal plug (col. 12, lines 15-28).
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 effect the barrier properties and the resistivity of the interconnect structure.
Pertaining to claim 18, Garg teaches a seed layer on the metal adhesion layer (col. 12, lines 32-34).
Pertaining to claim 19, Garg teaches the seed layer may be a different material from the material of the metal plug (col. 12, lines 32-34; col. 6, line 63 – col. 7, line 1).
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 either one of Takewaka or Garg, and Ting (and Lee for claim 1), 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 either one of Takewaka or Garg, and Ting (and Lee), 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 either one of Takewaka or Garg, and Ting (and Lee), 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 either one of Takewaka or 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.
Claim 7 is objected to as being dependent upon a rejected base claim, but would be allowable if rewritten in independent form including all of the limitations of the base claim and any intervening claims.
The following is a statement of reasons for the indication of allowable subject matter: Applicant’s arguments filed 1/20/2026 with respect to claim 7 are persuasive.
Response to Arguments
With the exception of claim 7, Applicant's arguments filed 1/20/2026 have been fully considered but they are not persuasive.
Applicant argues that the combination of Hung, Takewaka and Ting do not teach the claimed seed layer.
In response, these references are not relied upon for such a teaching. Rather, Lee is cited for such a teaching.
Applicant further argues that the combination of Hung, Takewaka and Ting does not teach the (111) phase being dominant over a (200) phase, i.e. there is more (111) phase than (200). Applicant first cites Hung’s lack of teaching of a TiN/adhesion layer having more (111) phase than (200).
In response, Hung is not relied upon for such a teaching. Rather, it is the combination of references that teach the claimed feature.
Applicant next cites Takewaka’s lack of teaching the TiN/adhesion layer being formed in a trench and over a silicide, as well as an assertion that Takewaka’s teaching of a (111) orientation does not equate to more (111) phase than (200) phase.
In response, Takewaka is not relied upon for teaching the trench and silicide. With respect to the phase, a phase entirely of (111) necessarily means that there is more (111) than (200). In other words, if the content of (200) is zero, then the content of (111) must be greater. With the exception of claim 7, the claim language does not require the presence of a (200) phase.
Applicant next cites Ting’s lack of teaching the TiN/adhesion layer or any crystalline phase composition thereof.
In response, Ting is not relied upon for such a teaching. Ting teaches a feature of the silicide, which is applicable to the silicide of Hung.
Applicant next argues that no rationale has been articulated for combining Hung, Takewaka, and Ting to arrive at the claimed invention.
In response, the rationales are included in the rejections, beginning with the phrase “It would have been obvious …”.
Applicant next addresses the rejections in view of the Garg reference. First, Applicant argues that the references do not teach “an epitaxial region in the semiconductor substrate and below the trench, wherein the epitaxial region is separate from the semiconductor substrate and resides directly below of entire bottom of the trench” as recited in claim 1.
In response, this claim language is not present in claim 1.
Applicant next makes an argument regarding Hung that reflects the same argument made in the combination with Takewaka. Thus, referral is made to the response above.
Applicant next argues that Garg does not teach the features of the trench, the gates, or the (111) phase dominant over the (200) phase.
In response, Garg is not relied upon to teach the trench and gates. With respect to the (111) phase, Garg teaches the (111) phase may be e.g. 95% or above (or even below 95%), and the other phases are one or a combination of (100), (200), and amorphous (col. 7, lines 47-53 and 61-64). Even so, the teaching of Garg would equate to more (111) than (200) phase even (or especially) if no (200) is present. With the exception of claim 7, the claim language does not require the presence of a (200) phase.
Next, Applicant makes an argument regarding claim 7 which, as noted in the Allowable Subject Matter section above, is found to be persuasive.
Applicant concludes making similar arguments as those with regards to the combination including Takewaka, and thus reference is made to the responses above.
Conclusion
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