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) 1, 3, 5, & 16-20 is/are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Lu (US Pub no. 2016/0225716 A1).
Regarding claim 1, Lu et al discloses A device (fig. 21)comprising:
a via(104) on a first conductive feature(103)[0016]; a dielectric layer(106a) adjacent the via(104)[0036], wherein a sidewall of the via (104)is separated from a sidewall of the dielectric layer(106a) by an air gap(112)[0041] fig. 21; a metal cap layer (104 of 106b) on a top surface of the via(104 of 106a), wherein the metal cap layer(104 of 106b) extends across the air gap (112)to a top surface of the dielectric layer; and a first etch stop layer (1902 part of 106b)on the top surface of the dielectric layer(106a) and on a sidewall surface of the metal cap layer(104 of 106b)[0044-0045].
Regarding claim 3, Lu et al discloses wherein a bottom surface of the metal cap layer (104 of 106b) is exposed by the air gap(112) fig. 21.
Regarding claim 5, Lu et al discloses wherein the via comprises a barrier layer (1402)surrounding a conductive layer (1502), wherein the barrier layer(1402) and the conductive layer are different materials[0038][0039].
Regarding claim 16, Lu et al discloses A semiconductor device(fig. 1) comprising: a transistor (103)over a substrate(102)[0022], wherein the transistor comprises: a gate stack(116) [0024]; and a first source/drain region(114)0024]; and a contact plug (104)on the gate stack(116) [0025], wherein the contact plug (104) comprises: a first layer of conductive material physically contacting the gate stack(116) fig. 1; a first air gap(112) laterally surrounding the first layer of conductive material(104)[0026] fig. 1; and a first cap layer (104 of 106)covering the first layer of conductive material (104 in 106 closest to substrate) ) and the first air gap(112) fig. 1.
Regarding claim 17, Lu et al discloses comprising a conductive feature(104 right of gate stack 116) fig. 1 over and electrically connected to the first source/drain region(114), wherein the conductive feature (104 right of gate stack 116) fig. 1 comprises: a second layer of conductive material[0025]; a second air gap(112) laterally surrounding the second layer of conductive material fig. 1; and a second cap layer(104-right of second 106) covering the second layer of conductive material and the
second air gap(112) fig. 1.
Regarding claim 18, Lu et al discloses further comprising a first etch stop layer (CESL), wherein the first etch stop layer laterally surrounds the first cap layer(104) [0025].
Regarding claim 19, Lu et al discloses further comprising a second etch stop
layer(CESL) on top surfaces of the first cap layer(104 of second 106) and the first etch stop layer(CESL) [0025].
Regarding claim 20, Lu et al discloses wherein the first cap layer (104 of 106 second layer) is a conductive material[0025].
Claim(s) 1-7 is/are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Chou (US Pub no. 2022/0406647 A1)
Regarding claim 1, Chou et al discloses A device comprising: a via on a first conductive feature(56)[0034]; a dielectric layer(34) adjacent the via(56)[0037], wherein a sidewall of the via(56) is separated from a sidewall of the dielectric layer(34) by an air gap(60)[0039]; a metal cap layer(58/58”/58’) on a top surface of the via(56), wherein the metal cap layer (58/58”/58’) [0042]extends across the air gap (60)to a top surface of the dielectric layer(34); and a first etch stop layer(64) on the top surface of the dielectric layer(34) and on a sidewall surface of the metal cap layer(58/58”/58’)[0047] fig. 17a.
Regarding claim 2, Chou et al discloses wherein the first etch stop layer (64)comprises a layer of aluminum nitride and a layer of aluminum oxide[0047].
Regarding claim 3, Chou et al discloses wherein a bottom surface of the metal cap layer(58/58”/58’) is exposed by the air gap(60) fig. 17a.
Regarding claim 4, Chou et al discloses wherein the metal cap layer (58/58”/58’)extends on a sidewall surface of the via(56) fig. 17a.
Regarding claim 5, Chou et al discloses wherein the via(56) comprises a barrier layer surrounding a conductive layer(54), wherein the barrier layer (52)and the conductive layer are different materials[0034-0035].
Regarding claim 6, Chou et al discloses wherein the metal cap layer(58/58”/58’) is a layer of cobalt[0038].
Regarding claim 7, Chou et al discloses wherein the sidewall surface of the metal cap layer (58/58”/58’)is convex fig. 17a.
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.
Claim(s) 8 is/are rejected under 35 U.S.C. 103 as being unpatentable over Chou (US Pub no. 2022/0406647 A1)
Regarding claim 8, Chou et al discloses , wherein the metal cap layer(58/58”/58’) has a thickness but fails to teach the range of 10 Å to 50 Å. It would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to achieve a thickness range of 10 Å to 50 Å through routine experimentation to control the extension of the metal cap. [W]here the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation." /in re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955)
Claim(s) 9-13 & 15 is/are rejected under 35 U.S.C. 103 as being unpatentable over Chou (US Pub no. 2022/0406647 A1) in view of Usami (US Pub no. 2015/0228586 A1).
Regarding claim 9, Chou et al discloses A device comprising:
a first conductive feature(56) in an insulating layer(34)[0037];
a dielectric layer (66)over the first conductive feature(56);
a second conductive feature(78) in the dielectric layer(66), wherein the second
conductive feature (78)is over and physically contacting the first conductive feature(56);
an air spacer (84) encircling the second conductive feature(78)[0051-0052], wherein sidewalls of the second conductive feature(78) are exposed to the air spacer(84)[0052];
a metal cap(86/86’) covering the second conductive feature (78)and extending over the air spacer(84)[0054], wherein the air spacer(84) is sealed by a bottom surface of the metal cap(86/86’); a first etch stop layer (88)on the dielectric layer(66), wherein a sidewall of the first etch stop layer (88)physically contacts a sidewall of the metal cap(86/86’)[0054] but fails to teach and a second etch stop layer extending on a top surface of the metal cap and a top surface of the first etch stop layer.
However, Usami et al teaches a damascene structure comprising a second etch stop layer(BR22)[0066]. It would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to modify Chou et al with the teachings of Usami et al such that a second etch stop layer extending on a top surface of the metal cap and a top surface of the first etch stop layer results to improve mechanical strength.
Regarding claim 10, Chou et al discloses wherein the sidewall of the metal cap (86/86’)has a convex profile and the sidewall of the first etch stop layer(88) has a concave profile fig. 17a.
Regarding claim 11, Chou et al discloses wherein the metal cap(86/86’)physically contacts a top surface of the dielectric layer(66) fig. 17a.
Regarding claim 12, Chou et al discloses wherein the metal cap(86/86’) comprises cobalt[0038][0054].
Regarding claim 13, Chou et al discloses wherein the second conductive feature (78)comprises a barrier layer (76)over a metal layer(78), wherein the barrier layer (76)is between the metal layer and the first conductive feature[0051].
Regarding claim 15, Chou et al discloses wherein the sidewall of the first etch stop layer(88) is concave fig. 17a.
Claim(s) 14 is/are rejected under 35 U.S.C. 103 as being unpatentable over Chou (US Pub no. 2022/0406647 A1) in view of Usami (US Pub no. 2015/0228586 A1) as applied to claim 13 and further in view of Lu (US Pub no. 2016/0225716 A1).
Regarding claim 14, Chou et al as modified by Usami et al discloses all the claim limitations of claim 13 but fails to teach wherein the barrier layer comprises cobalt.
However, Lu et al discloses a barrier layer (1402)comprising cobalt[0038]. It would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to further modify Chou et al and Usami et al with the teachings of Lu et al the substitution of one known element for another yields predictable results. In re Fout, 675 F.2d 297, 213 USPQ 532 (CCPA 1982)
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to LATANYA N CRAWFORD EASON whose telephone number is (571)270-3208. The examiner can normally be reached Monday-Friday 8:30 AM-4:30 PM.
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/LATANYA N CRAWFORD EASON/ Primary Examiner, Art Unit 2813
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