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 § 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 1-7, 10, 24 are rejected under 35 U.S.C. 103 as being unpatentable over Mukesh et al (US Publication No. 2023/0402378) in view of Xie et al (US Publication No. 2023/0178433) and Kim et al (US Publication No. 2020/0373331).
Regarding claim 1, Mukesh discloses a method for forming a semiconductor device structure, comprising: forming a first fin structure and a second fin structure over a substrate Fig 2B; partially removing the substrate to form a trench Fig 2B, 214between the first fin structure and the second fin structure Fig 2B, 214 and Fig 2G, 228; forming a sacrificial structure Fig 2H, 234/228 fill the trench; forming a source and drain region on the first fin structure; forming a conductive contact Fig 2P, 250 over the source and drain region; and replacing the sacrificial structure with a conductive structure Fig 2M. Mukesh discloses all the limitations except the order of the forming the conductive contact and the replacement of the sacrificial structure.
Whereas Xie discloses forming an epitaxial structure on the first fin structure Fig 8, 50 ¶0058; forming a conductive contact Fig 10, 56 over the epitaxial structure Fig 10, 50 and the sacrificial structure Fig 10, 40/42/46 ¶0049-0053; wherein the conductive contact Fig 10, 56 is formed after the epitaxial structure is formed ¶0058 Fig 8; exposing a bottom of the sacrificial structure Fig 10; removing the sacrificial structure from the bottom of the sacrificial structure to form an opening exposing the conductive contact Fig 15 ¶0076-0077 and forming a conductive structure Fig 16, 110 filling the opening and reaching the conductive contact Fig 16, and the conductive structure is formed after the epitaxial structure is formed Fig 16. Mukesh and Xie are analogous art because they are directed to buried power rails and one of ordinary skill in the art would have had a reasonable expectation of success to modify Mukesh because they are from the same field of endeavor. Therefore it would have been obvious to one having ordinary skill of the art before the effective filing date of the claimed invention to modify the method of Mukesh and incorporate the teachings of Xie to provide and ease in manufacturing the buried power rails avoiding contamination ¶0050. Mukesh discloses all the limitations but silent on the arrangement of the conductive structure. Whereas Kim discloses wherein a top surface of the conductive structure is vertically positioned between a bottom of the first fin structure and an interface between the first fin structure and the epitaxial structure Fig 1B and Fig 18. Mukesh and Kim are analogous art because they are directed to buried power rails and one of ordinary skill in the art would have had a reasonable expectation of success to modify Mukesh because they are from the same field of endeavor. Therefore it would have been obvious to one having ordinary skill of the art before the effective filing date of the claimed invention to modify the method of Mukesh and incorporate the teachings of Kim to provide insulation distance between wiring layers.
Regarding claim 2, Xie discloses thinning the substrate from a lower surface of the substrate so that a bottom of the sacrificial structure is exposed Fig 11-12.
Regarding claim 3, Xie and Mukesh discloses further comprising: forming an interconnection structure over the conductive contact; and bonding a carrier substrate to the interconnection structure before the substrate is thinned Xie-Fig 11-12 and Mukesh- Fig 2P.
Regarding claim 4, Mukesh discloses further comprising: forming a first spacer layer along sidewalls of the first fin structure and the second fin structure before the trench is formed; and forming a second spacer layer along sidewalls of the trench before the sacrificial structure is formed Fig 2B-2F.
Regarding claim 5, Xie in view of Mukesh discloses forming an isolation structure Fig 7, 30’, over the sacrificial structure Fig 7, 40, wherein the isolation structure surrounds lower portions of the first fin structure and the second fin structure Fig 7.
Regarding claim 6, Mukesh in view of Xie discloses recessing the first fin structure before the epitaxial structure is formed Fig2C-2E.
Regarding claim 7, Mukesh in view of Xie discloses wherein the conductive structure is formed to be in direct contact with a bottom of the conductive contact Fig 5.
Regarding claim 10, Xie in view of Mukesh discloses wherein the sacrificial structure Fig 7 is made of a dielectric material ¶0055.
Regarding claim 24, Xie discloses wherein the opening partially exposes the isolation structure Fig 15.
Claims 8, 11-18, 20, 22-23 are rejected under 35 U.S.C. 103 as being unpatentable over Mukesh et al (US Publication No. 2023/0402378) in view of Xie et al (US Publication No. 2023/0178433), Kim et al (US Publication No. 2020/0373331) and Chiang et al (US Publication No. 2020/0135634).
Regarding claim 8, Mukesh discloses all the limitations but silent on the metal semiconductor compound layer between the epitaxial structure and the contact. Whereas Chiang discloses forming a metal-semiconductor compound layer between the epitaxial structure and the conductive contact ¶0081 Fig 21, 84. Mukesh and Chiang are analogous art because they are directed to buried power rails and one of ordinary skill in the art would have had a reasonable expectation of success to modify Mukesh because they are from the same field of endeavor. Therefore it would have been obvious to one having ordinary skill of the art before the effective filing date of the claimed invention to modify the method of Mukesh and incorporate the teachings of Chiang to improve interconnection.
Regarding claim 11, Mukesh discloses a method for forming a semiconductor device structure, comprising: forming a fin structure over a substrate Fig 2B; forming a sacrificial structure beside the fin structure, wherein a bottom surface of the fin structure is vertically between a top of the sacrificial structure and a bottom of the sacrificial structure Fig 2D and Fig 2N ; forming a source and drain region on the fin structure Fig 2P; forming a dielectric layer over the source and drain region and the sacrificial structure Fig 2P;forming a conductive contact Fig 2P, 250 at least partially covering the source and drain region and the sacrificial structure Fig 2P ; and forming a conductive structure in the trench Fig 2M. Mukesh discloses all the limitations except the order of the forming the conductive contact and the replacement of the sacrificial structure. Whereas Xie discloses forming an epitaxial structure on the fin structure¶0042; forming a conductive contact at least partially covering the epitaxial structure and the sacrificial structure Fig 9-10 ¶0044; wherein the conductive contact Fig 10, 56 is formed after the epitaxial structure is formed ¶0058 Fig 8; exposing a bottom of the sacrificial structure Fig 10; removing the sacrificial structure from the bottom of the sacrificial structure to form an trench exposing the conductive contact Fig 15 ¶0076-0077 and forming a conductive structure Fig 16, 110 in the trench Fig 16, and the conductive structure is formed after the epitaxial structure is formed Fig 16.Mukesh and Xie are analogous art because they are directed to buried power rails and one of ordinary skill in the art would have had a reasonable expectation of success to modify Mukesh because they are from the same field of endeavor. Therefore it would have been obvious to one having ordinary skill of the art before the effective filing date of the claimed invention to modify the method of Mukesh and incorporate the teachings of Xie to provide and ease in manufacturing the buried power rails avoiding contamination ¶0050. Mukesh discloses all the limitations but silent on the arrangement of the conductive structure. Whereas Kim discloses wherein a top surface of the structure is vertically between the bottom surface of the fin structure and a bottom of the epitaxial structure Fig 1B and Fig 18. Mukesh and Kim are analogous art because they are directed to buried power rails and one of ordinary skill in the art would have had a reasonable expectation of success to modify Mukesh because they are from the same field of endeavor. Therefore it would have been obvious to one having ordinary skill of the art before the effective filing date of the claimed invention to modify the method of Mukesh and incorporate the teachings of Kim to provide insulation distance between wiring layers. Mukesh, Xie and Kim discloses all the limitations except for the dielectric layer. Whereas Chiang discloses forming a dielectric layer Fig 19/20, 80 over the epitaxial structure and the sacrificial structure; partially removing the dielectric layer Fig 19/20, 80 to form a contact opening, wherein the contact opening exposes an upper slanted surface of the epitaxial structure Fig 19/20, a lower slanted surface of the epitaxial structure, and the sacrificial structure Fig 19/20; forming a conductive contact Fig 21/22, 86 that extends along the upper slanted surface and the lower slanted surface of the epitaxial structure Fig 21/22. Mukesh and Chiang are analogous art because they are directed to buried power rails and one of ordinary skill in the art would have had a reasonable expectation of success to modify Mukesh because they are from the same field of endeavor. Therefore it would have been obvious to one having ordinary skill of the art before the effective filing date of the claimed invention to modify the method of Mukesh and incorporate the teachings of Chiang to provide additional insulation/protection around the source/drain region for subsequent processing.
Regarding claim 12, Xie discloses further comprising: thinning the substrate from a lower surface of the substrate so that the bottom of the sacrificial structure is exposed Fig 9-10.
Regarding claim 13, Mukesh discloses comprising: forming a spacer layer Fig 2I, 230 before the sacrificial structure is formed, wherein the spacer layer extends along sidewalls and a bottom of the sacrificial structure after the sacrificial structure is formed Fig 2I-2N.
Regarding claim 14, Xie in view of Mukesh discloses partially removing a lower portion of the spacer layer after the trench is formed and before the conductive structure is formed Fig 10-13.
Regarding claim15, Mukesh discloses wherein the sacrificial structure comprises an oxide material, a nitride material, or a combination thereof ¶0058,0064-0066.
Regarding claim16, Mukesh discloses a semiconductor device structure, comprising: a semiconductor fin over a substrate Fig 2B; an source drain structure on the semiconductor fin Fig 5; a conductive contact Fig 2P, 250 electrically connected to the source drain structure Fig 5; and a conductive structure extending from a bottom surface of the substrate towards the conductive contact Fig 4-5, wherein the conductive structure is electrically connected to the conductive contact Fig 4-5. Mukesh discloses all the limitations except the epitaxial structure. Whereas Xie discloses forming an epitaxial structure on the first fin structure¶0042; forming a conductive contact Fig 10 over the epitaxial structure Fig 13-14; an isolation structure Fig 8, 54 laterally surrounding the semiconductor fin Fig 8 ¶0058, wherein the isolation structure has a portion positioned beside the conductive contact Fig 8, 56; and a conductive structure Fig 16, 110 continuously extending from a bottom surface of the substrate towards the conductive contact and reaching the conductive contact Fig 16, 56 and an interface between the conductive contact Fig 16, 56 and the portion of the isolation structure Fig 16, 54. Mukesh and Xie are analogous art because they are directed to buried power rails and one of ordinary skill in the art would have had a reasonable expectation of success to modify Mukesh because they are from the same field of endeavor. Therefore it would have been obvious to one having ordinary skill of the art before the effective filing date of the claimed invention to modify the device of Mukesh and incorporate the teachings of Xie to provide an effective source and drain region. Mukesh discloses all the limitations but silent on the arrangement of the conductive structure. Whereas Kim discloses wherein a top surface of the conductive structure is vertically positioned between a bottom of the first fin structure and an interface between the first fin structure and the epitaxial structure Fig 1B and Fig 18. Mukesh and Kim are analogous art because they are directed to buried power rails and one of ordinary skill in the art would have had a reasonable expectation of success to modify Mukesh because they are from the same field of endeavor. Therefore it would have been obvious to one having ordinary skill of the art before the effective filing date of the claimed invention to modify the method of Mukesh and incorporate the teachings of Kim to provide insulation distance between wiring layers. Mukesh, Xie and Kim discloses all the limitations except for the dielectric layer. Whereas Chiang discloses wherein a portion of the conductive contact Fig 21/22, 86 is vertically between the epitaxial structure Fig 21/22, 76 and a top of the conductive structure Fig 21/22, 48 and laterally between the semiconductor fin Fig 21/22, 30 and an outermost edge of the epitaxial structure Fig 21/22. Mukesh and Chiang are analogous art because they are directed to buried power rails and one of ordinary skill in the art would have had a reasonable expectation of success to modify Mukesh because they are from the same field of endeavor. Therefore it would have been obvious to one having ordinary skill of the art before the effective filing date of the claimed invention to modify the method of Mukesh and incorporate the teachings of Chiang to improve device interconnection.
Regarding claim 18, Xie discloses a dielectric spacer layer Fig 16, 104 between the conductive contact and the substrate Fig 16.
Regarding claim 20, Xie discloses wherein the conductive contact Fig 13, 56 extends across a topmost surface of the epitaxial structure and a bottommost surface of the epitaxial structure Fig 13.
Regarding claim 22, Chiang discloses a support element between the epitaxial structure and the conductive contact, wherein the conductive contact extends along a top of the support element and a sidewall of the support element Fig 21-22.
Regarding claim 23, Chiang discloses a metal-semiconductor compound layer between the epitaxial structure and the conductive contact ¶0081 Fig 21,84, wherein the metal-semiconductor compound layer and the support element together surround a corner region, and the conductive contact fills the corner region Fig 21-22.
Response to Arguments
Applicant's arguments filed January 20, 2026 have been fully considered but they are not persuasive. The added limitations to claims 1, 11 and 16 are disclosed by Xie 2023/0178433. The detailed rejection to the added limitations are described in detail above.
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.
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/CHRISTINE A ENAD/Primary Examiner, Art Unit 2811