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 .
Election/Restrictions
Applicant’s election without traverse of Group I and Species 1 (Fig. 2M) in the reply filed on 12/2/2025 is acknowledged. Claims 6-7 is directed to Species 4, Fig. 8F with “the barrier-free source/drain contact includes a first molybdenum plug (330) disposed over a first tungsten plug (320)”. As such, the claims are also withdrawn for examination.
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.
1. Claim(s) 1-5, 18-20 are rejected under 35 U.S.C. 102a(1) as being anticipated by US 20230178476 A1 (Kang).
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Regarding claim 1, Kang shows (Fig. 2A-2B) an interconnect structure comprising:
an insulator layer (149+184+140, para 36, 51);
a barrier-free source/drain contact (CA, 156+154, para 39) disposed in the insulator layer, wherein the barrier-free source/drain contact is disposed on an epitaxial source/drain (130, para 31) and the barrier-free source/drain contact includes tungsten, molybdenum, or a combination thereof (para 48);
a barrier-free source/drain via (CAV, para 53) disposed in the insulator layer, wherein the barrier-free source/drain via is disposed on the barrier-free source/drain contact and the barrier-free source/drain via includes molybdenum (para 53); and
a barrier-free gate via (CB or 194+196, para 56) disposed in the insulator layer, wherein the barrier-free gate via is disposed on a gate stack (GL+132, para 23) disposed adjacent to the epitaxial source/drain and the barrier-free gate via includes tungsten, molybdenum, or a combination thereof (para 44 and 59, 196 same material as 156).
Regarding claim 2, Kang shows (Fig. 2A-2B) wherein the barrier-free source/drain contact (156, W, para 48) is a first tungsten plug, the barrier-free source/drain via is a molybdenum plug (CAV, Mo, para 53), and the barrier-free gate via is a second tungsten plug (CB or 194+196, 56, tungsten as 196 same material as 156).
Regarding claim 3, Kang shows (Fig. 2A-2B) wherein the barrier-free source/drain contact is a first molybdenum plug (156, Mo, para 48), the barrier-free source/drain via is a second molybdenum plug (CAV, Mo, para 53), and the barrier-free gate via is a tungsten plug (CB or 194+196, 56, tungsten as 196 same material as 156).
Regarding claim 4, Kang shows (Fig. 2A-2B) wherein the barrier-free source/drain contact is a tungsten plug (156, W, para 48), the barrier-free source/drain via is a first molybdenum plug (CAV, Mo, para 53), and the barrier-free gate via is a second molybdenum plug (CB or 194+196, 56, Mo as 196 same material as 156).
Regarding claim 5, Kang shows (Fig. 2A-2B) wherein the barrier-free source/drain contact is a first molybdenum plug (156, Mo, para 48), the barrier-free source/drain via is a second molybdenum plug (CAV, Mo, para 53), and the barrier-free gate via is a third molybdenum plug (CB or 194+196, 56, Mo as 196 same material as 156).
Regarding claim 18, Kang shows (Fig. 2A-2B) an interconnect structure comprising:
a first interlayer dielectric (ILD) layer (140,149, para 36);
a second ILD layer (184, para 51) disposed over the first ILD layer;
a source/drain contact plug (CA, 156+154, para 39) disposed in the first ILD layer, wherein sidewalls of the source/drain contact plug abut the first ILD layer, the source/drain contact plug is disposed on an epitaxial source/drain (130, para 31), and the source/drain contact plug includes tungsten, molybdenum, or a combination thereof (para 48);
a molybdenum source/drain via plug (CAV, para 53) disposed in the second ILD layer, wherein sidewalls of the molybdenum source/drain via plug abut the second ILD layer and the molybdenum source/drain via plug is disposed on the source/drain contact plug; and
a molybdenum gate via plug (CB or 194+196, para 56) disposed in the second ILD layer, wherein the sidewalls of the molybdenum gate via abut the second ILD layer and the molybdenum gate via plug is disposed on a gate stack (GL+132, para 23) disposed adjacent to the epitaxial source/drain.
Regarding claim 19, Kang shows (Fig. 2A-2B) wherein the source/drain contact plug includes a molybdenum plug (156, Mo, para 48).
Regarding claim 20, Kang shows (Fig. 2A-2B) wherein the source/drain contact plug includes a tungsten plug (156, W, para 48).
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.
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
1. Claim(s) 8-9 is/are rejected under 35 U.S.C. 103 as being unpatentable over Kang as applied to claim 1 above, further in view of US 20210098368 A1 (Yu).
Regarding claim 8, Kang shows the barrier-free source/drain via.
Kang does not show wherein a width of the barrier-free source/drain via is less than about 16 nm.
Yu shows (Fig. 2E) wherein a width of the barrier-free source/drain via (140a, para 44) is less than about 16 nm.
It would have been obvious to one of ordinary skill in the art, at or before the effective filing date of the invention was made, to add the invention of Yu, with source/drain via width, to the invention of Kang.
The motivation to do so is that the combination produces the predictable result of having more transistors in a chip with greater numbers of via contacts with lesser widths.
Regarding claim 9, Kang as previously modified with Yu shows wherein the barrier-free source/drain via (140a, Yu) has a top width and a bottom width, wherein a difference between the top width and the bottom width is less than about 2 nm.
2. Claim(s) 21-22 is/are rejected under 35 U.S.C. 103 as being unpatentable over Kang as applied to claim 18 above, further in view of US 20220069100 A1 (Hwang).
Regarding claim 21, Kang shows molybdenum source/drain via plug and second ILD layer.
Kang does not show wherein a bottom of the molybdenum source/drain via plug is lower than a bottom of the second ILD layer.
Hwang shows (Fig. 3) wherein a bottom of the molybdenum source/drain via plug (VM, para 53) is lower than a bottom of the second ILD layer (172).
Thus, it would have been obvious to one of ordinary skill in the art at the time the invention was made to use molybdenum source/drain via plug according to the teaching of “Hwang”, since it has been held to be within the general skill of a worker in the art to select a known “interconnect stack” on the basis of its suitability for the intended use as a matter of obvious design choice, In re Leshin, 125 USPQ 416 (CCPA 1960). Moreover, the court has held that a simple substitution of one known element for another to obtain predictable results is obvious. KSR Int'l v. Teleflex Inc., 127 S.Ct. 1727 (2007).
Regarding claim 22, Kang as previously modified with Hwang shows further comprising an etch stop layer (171, Hwang Fig. 3 para 35) disposed between the first ILD layer (162, Hwang Fig. 3) and the second ILD layer (172, Hwang Fig. 3), wherein both the molybdenum source/drain via plug and molybdenum gate via plug (VM of 190, para 33, Hwang Fig. 2C) abut the etch stop layer.
3. Claim(s) 23,25 is/are rejected under 35 U.S.C. 103 as being unpatentable over Kang in view of Hwang.
Regarding claim 23, Kang shows (Fig. 2A-2B) a device comprising:
a first level of a multilayer interconnect (MLI) (CA, 156+154, para 39) that includes a tungsten interconnect (para 48), wherein the tungsten interconnect has sidewalls interfacing a dielectric structure (149+184+140, para 36); and
a second level of the MLI (CAV+CB or 194+196, para 53,56) that includes a first molybdenum interconnect (CAV) and a second molybdenum interconnect (CB), wherein the second level of the MLI is over the first level of the MLI, the first molybdenum interconnect has sidewalls interfacing the dielectric structure and a bottom interfacing the tungsten interconnect, the second molybdenum interconnect has sidewalls interfacing the dielectric structure.
Kang does not show the first molybdenum interconnect extends below the second level of the MLI into the first level of the MLI.
Hwang shows (Fig. 3) the first molybdenum interconnect (VM, para 53) extends below the second level of the MLI (below the bottom level of 172) into the first level of the MLI (top of 162+161 which includes tungsten interconnect 185, para 42).
Thus, it would have been obvious to one of ordinary skill in the art at the time the invention was made to use first molybdenum interconnect according to the teaching of “Hwang”, since it has been held to be within the general skill of a worker in the art to select a known “interconnect stack” on the basis of its suitability for the intended use as a matter of obvious design choice, In re Leshin, 125 USPQ 416 (CCPA 1960). Moreover, the court has held that a simple substitution of one known element for another to obtain predictable results is obvious. KSR Int'l v. Teleflex Inc., 127 S.Ct. 1727 (2007).
Regarding claim 25, Kang as previously modified with Hwang shows wherein a curved interface is between the bottom of the first molybdenum interconnect (VM, Hwang) and the tungsten interconnect (185, Hwang).
Allowable Subject Matter
Claims 10,24, 26-27 are 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.
Regarding claim 10, the prior art of record, either singularly or in combination, does not disclose or suggest the combination of limitations including “distance between a top surface of the barrier-free source/drain via and a top surface of the gate stack is less than about 5 nm”.
Regarding claim 24, the prior art of record, either singularly or in combination, does not disclose or suggest the combination of limitations including “the first height is greater than the second height”.
Regarding claim 26, the prior art of record, either singularly or in combination, does not disclose or suggest the combination of limitations including “wherein a difference between a top width of the first molybdenum interconnect and a bottom width of the first molybdenum interconnect is less than about 2 nm”.
Regarding claim 27, the prior art of record, either singularly or in combination, does not disclose or suggest the combination of limitations including “the first height is greater than the second height”.
Conclusion
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/WASIUL HAIDER/Primary Examiner, Art Unit 2812