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
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.
Claim(s) 7, 9, 14 and 15 is/are rejected under 35 U.S.C. 102a1 as being anticipated by Filippi et al. (US Pat. Pub. 2006/0073695).
Regarding claim 7, Filippi teaches a structure comprising:
a first conductive feature [fig. 9, 110];
a second conductive feature over and electrically coupling to the first conductive feature [fig. 9, 170/137/138], wherein the second conductive feature comprises:
a diffusion barrier [fig. 9, 170]; and
a metallic material in a basin formed by the diffusion barrier [fig. 9, 137/138 are surrounded by 170];
an air spacer encircling a top portion of the second conductive feature [fig. 9, 190 encircles 170/137/138]; and
a dielectric layer encircling the air spacer [fig. 9, 120].
Regarding claim 9, Filippi discloses the structure of claim 7, wherein the air spacer has substantially unform width [fig. 9, 190 has a uniform thickness from the edge of the second conductive structure to the dielectric layer].
Regarding claim 14, Filippi teaches the structure of claim 7, further comprising an etch stop layer overlapping the second conductive feature, the air spacer and the dielectric layer [fig. 9, 200].
Regarding claim 15, Filippi discloses the structure of claim 7, wherein a sidewall of the dielectric layer is exposed to the air spacer [fig. 7, an alternative embodiment allows a sidewall of dielectric layer 120 to be exposed to the air spacer 202].
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(s) 1-6, 16-19 is/are rejected under 35 U.S.C. 103 as being unpatentable over Filippi as applied to claims 7, 9, 14 and 15 above, and further in view of Hong et al. (US Pat. 2019/0221475).
Regarding claim 1, Filippi teaches a structure comprising:
a first conductive feature [fig. 9, 110];
a dielectric layer over the first conductive feature [fig. 9, 120];
a second conductive feature in the dielectric layer, wherein the second conductive feature is over and contacting the first conductive feature [fig. 9, 170/137/138 is in 120 and contacting 110];
an air spacer encircling the second conductive feature, wherein sidewalls of the second conductive feature are exposed to the air spacer [fig. 9, 190 encircles 170/137/138 and sidewalls of 170/137/138 are exposed to 190]; and
a second etch stop layer over and contacting the dielectric layer, wherein the second etch stop layer is further over the second conductive feature [fig. 9, 200].
Filippi fails to teach an etch stop layer over the first conductive feature. However, Hong teaches an interconnect structure with a first conductive feature and an etch stop layer over the first conductive feature, the second conductive feature being in the dielectric layer above the first conductive feature and the first etch stop layer [fig. 1, first conductive feature 7/9, etch stop layer 13, second conductive feature Wa/Va extending through etch stop 13].
It would have been obvious to one of ordinary skill in the art at the time of the invention to incorporate the teachings of Hong into the method of Filippi by forming an etch stop layer over the first conductive feature. The ordinary artisan would have been motivated to modify Filippi in the manner set forth above for at least the purpose of utilizing layers and processes to create a interconnect structure which has reduced parasitic capacitance and increased signal transmission speed [Hong, paragraph [0072]].
Regarding claim 2, Filippi in view of Hong discloses the structure of claim 1, wherein the air spacer has a substantially uniform thickness [Filippi, fig. 9, 190 has a uniform thickness from the edge of the second conductive structure to the dielectric layer].
Regarding claim 3, Filippi in view of Hong teaches the structure of claim 1, wherein the air spacer extends from a top surface of the dielectric layer to a bottom surface of the first etch stop layer [Filippi, fig. 9, 190 extends from a top surface of 120 to the top surface of 110, which would have it extend through the etch stop layer, the bottom of the etch stop layer would be at the top of 110].
Regarding claim 4, Filippi in view of Hong discloses the structure of claim 1, further comprising a dielectric material underlying and contacting a bottom portion of the of the second conductive feature, wherein a top portion of the second conductive feature is exposed to the air spacer [Filippi, fig. 8, an alternative embodiment shows a dielectric material 160 underlying 137 and contacting 170/138 of 170/138/137 and a top portion 137/170 is exposed to 190].
Regarding claim 5, Filippi in view of Hong teaches the structure of claim 4, wherein the dielectric material encircles the bottom portion of the second conductive feature and the dielectric material and the dielectric layer are formed of different materials [Filippi, fig. 8, 160 encircles 170/138, paragraph [0020] teaches 150 (160 after processing) is silicon dioxide, paragraph [0018] teaches 120 can be materials other than silicon dioxide].
With respect to the dielectric material forming a ring as it encircles the second conductive feature, Filippi in view of Hong fail to teach the actual three dimensional shape of the interconnect structure. However, this appears to be merely a change in shape of overall conductive structure and surrounding dielectric and one of ordinary skill in the art would have been led to this configuration through routine experimentation and optimization to achieve desired interconnect performance such as resistivity or parasitic capacitance. Applicant has not disclosed that the shape is for a particular unobvious purpose, produces an unexpected result, or is otherwise critical, see In re Dailey, 357 F.2d 669, 149 USPQ 47 (CCPA 1966). See also MPEP 2144.04(IV)(B).
Regarding claim 6, Filippi in view of Hong discloses the structure of claim 1, wherein no dielectric material is between the second conductive feature and the air spacer [Filippi, fig. 9, no dielectric material is between 170/137/138 and 190].
Regarding claim 16, Filippi teaches a structure comprising:
a dielectric layer [fig. 9, 120];
a conductive feature in the dielectric layer, wherein the conductive feature extends from a bottom surface level of the dielectric layer to a top surface level of the dielectric layer [fig. 9, 170/137/138];
a second dielectric etch stop layer over and contacting the dielectric layer, wherein the second dielectric etch stop layer comprises a bottom surface at the top surface level of the dielectric layer [fig. 9, 200]; and
an air spacer between the conductive feature and the dielectric layer [fig. 9, 190].
Filippi fails to teach an etch stop layer below the dielectric layer However, Hong teaches an interconnect structure with a first conductive feature and an etch stop layer over the first conductive feature, the second conductive feature being in the dielectric layer above the first conductive feature and the first etch stop layer [fig. 1, first conductive feature 7/9, etch stop layer 13, second conductive feature Wa/Va extending through etch stop 13].
It would have been obvious to one of ordinary skill in the art at the time of the invention to incorporate the teachings of Hong into the method of Filippi by forming an etch stop layer below the dielectric layer and allowing the conductive feature to extend from a bottom surface of the dielectric etch stop layer to the top surface of the dielectric layer. The ordinary artisan would have been motivated to modify Filippi in the manner set forth above for at least the purpose of utilizing layers and processes to create a interconnect structure which has reduced parasitic capacitance and increased signal transmission speed [Hong, paragraph [0072]].
Regarding claim 17, Filippi in view of Hong discloses the structure of claim 16, wherein a first sidewall of the conductive feature and a second sidewall of the dielectric layer are exposed to the air spacer [Filippi, fig. 7, an alternative embodiment allows a sidewall of dielectric layer 120 to be exposed to the air spacer 202, 170/137/138 are also exposed to the air spacer].
Regarding claim 18, Filippi in view of Hong teaches the structure of claim 16, wherein a bottom surface of the air spacer is higher than an interface between the first dielectric etch stop layer and the dielectric layer [Filippi, fig. 7, a bottom surface of 202 is higher than an interface between 120 and the etch stop layer formed on layer 100].
Regarding claim 19, Filippi in view of Hong discloses the structure of claim 18, further comprising a material underlying the air spacer, wherein the material contacts a first sidewall of the dielectric layer and a second sidewall of the conductive feature to form interfaces [Filippi, fig. 7, 160 underlying air spacer 202 touches sidewalls of 120 and 170/137/138 which would create interfaces].
Claim(s) 20 is/are rejected under 35 U.S.C. 103 as being unpatentable over Filippi in view of Hong as applied to claims 1-6, 16-19 above, and further in view of Ting (US Pat. Pub. 2015/0332999).
Regarding claim 20 Filippi in view of Hong fails to teach a metal cap layer over and contacting the conductive feature, a portion of the metal cap overlaps part of the air spacer. However, Ting teaches an interconnect structure surrounded by an air spacer including a cap layer that is made of metal and is over and in contact with the conductive feature and overlaps the air spacer [fig. 2, metal cap 107, conductive feature 108/103, air spacer 101a’, paragraph [0026] teaches 107 can contain metal].
It would have been obvious to one of ordinary skill in the art at the time of the invention to incorporate the teachings of Ting into the method of Filippi in view of Hong by forming a metal cap over and contacting the conductive feature, a portion of the metal cap overlaps a part of the air spacer. The ordinary artisan would have been motivated to modify Filippi in view of Hong in the manner set forth above for at least the purpose of providing structural support allowing additional layers and metal lines to be formed above during further processing [Ting, paragraph [0026]].
Allowable Subject Matter
Claims 8, 10-13 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.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to JOHN M PARKER whose telephone number is (571)272-8794. The examiner can normally be reached M-F 7:30am - 3:30pm.
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/JOHN M PARKER/Primary Examiner, Art Unit 2899
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