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 .
Response to Amendment
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.
Claims 1-13 are rejected under 35 U.S.C. 103 as being unpatentable over Huang et al. (“Huang”), US 2021/0375857 (listed in the IDS dated 8-15-2024) in view of Chang et al. (“Chang”), US 2021/0376155 (listed in the IDS dated 8-15-2024).
Regarding Claim 1, Huang discloses a semiconductor device (Figs. 20A-21D; ¶ 0005-0008, 0063) comprising:
a channel structure (124; Figs. 20B, 21B; ¶ 0043 “124 are referred to as channels of the semiconductor device”);
source/drain regions (230, 240; Fig. 21B; ¶ 0064 “S/D epitaxial structures (e.g., the top epitaxial structures 240 and/or the bottom epitaxial structures 230) as sources and/or drains”) connected by the channel structure (¶ 0064 “S/D epitaxial structures are electrically connected to the second semiconductor layers 124”); and
a backside contact structure (360, 362, 364, 366; Figs. 20E, 21B-21C; ¶ 0065) below at least one of the source/drain regions (¶ 0062 “backside via 360 is electrically connected to the etched top epitaxial structure 240”, ¶ 0064 “backside via 360 is connected to the backside of one of the S/D epitaxial structures”),
wherein the backside contact structure comprises an upper portion (362; Fig. 20E; ¶ 0065 “backside via 360 includes a first portion 362”) having a first interface with the at least one of the source/drain regions (Fig. 20E; ¶ 0062 “backside via 360 is…formed…above the backside metal alloy layer 350” “As such, the backside via 360 is electrically connected to the etched top epitaxial structure 240.”) and a lower portion (364; Fig. 20E; ¶ 0065 “backside via 360 includes…a second portion 364”) having a second interface opposite the first interface (Fig. 20E; ¶ 0065 “first portion 362 is closer to the top epitaxial structure 240 than the second portion 364”),
wherein, in a 1st-direction cross section view (Figs. 20A, 20B, 20E; ¶ 0063, 0065), a width (W1; Fig. 20E; ¶ 0065 “width W1 of the first portion 362”) of the upper portion (362; Fig. 20E; ¶ 0065) of the backside contact structure along the first interface (Fig. 20E; ¶ 0065 “first portion 362 is closer to the top epitaxial structure 240 than the second portion 364”) is smaller than (¶ 0065 “width W1 of the first portion 362 is less than a width W2 of the second portion 364”) a width (W2; Fig. 2E; ¶ 0065 “width W2 of the second portion 364”) of the lower portion (364, 366; Fig. 20E; ¶ 0065) of the backside contact structure along the second interface (Fig. 20E; ¶ 0065 “first portion 362 is closer to the top epitaxial structure 240 than the second portion 364”).
Huang does not disclose
wherein, in a 2nd-direction cross-section view, widths of the upper portion of the backside contact structure along the first interface and the lower portion of the backside contact structure along the second interface are substantially uniform with each other along a vertical downward direction, and
wherein the 1st direction intersects the 2nd direction.
Chang discloses
wherein, in a 2nd-direction cross-section view (Fig. 27B; ¶ 0096), widths of the upper portion (Fig. 27B the upper portion of backside contact structure 130 physically contacting and electrically coupled to silicide region 129 of source/drain region 92, as marked in the annotated Fig. 27B infra; ¶ 0096) of the backside contact structure (130; Fig. 27B; ¶ 0096 “backside vias 130”) along the first interface (Fig. 27B; ¶ 0096 “backside vias 130 are electrically coupled to the first epitaxial source/drain regions 92 through the second silicide regions 129”) and the lower portion (Fig. 27B the lower portion of backside contact structure 130 in STI region 68, as marked in the annotated Fig. 27B infra) of the backside contact structure along the second interface (Fig. 27B the lower portion of 130 in STI region 68 is a second interface opposite the first interface; ¶ 0096) are substantially uniform with each other along a vertical downward direction (Fig. 27B; ¶ 0096), and
wherein the 1st direction intersects the 2nd direction (Fig. 1; ¶ 0013-0015).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention for Huang to have wherein, in a 2nd-direction cross-section view, widths of the upper portion of the backside contact structure along the first interface and the lower portion of the backside contact structure along the second interface are substantially uniform with each other along a vertical downward direction, and wherein the 1st direction intersects the 2nd direction, as taught by Chang, to “reduce RC time delay” and “improve device performance” (Chang ¶ 0097).
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Regarding Claim 2, Huang does not disclose wherein, in the 2nd-direction cross-section view, the width of the upper portion is substantially equal to the width of the lower portion.
Chang discloses wherein, in the 2nd-direction cross-section view, the width of the upper portion (Fig. 27B the upper portion of backside contact structure 130 in STI region 68) is substantially equal to the width of the lower portion (Fig. 27B the lower portion of backside contact structure 130 electrically coupled to silicide region 129 of source/drain region 92; ¶ 0096).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention for Huang to have wherein, in the 2nd-direction cross-section view, the width of the upper portion is substantially equal to the width of the lower portion, as taught by Chang, to “reduce RC time delay” and “improve device performance” (Chang ¶ 0097).
Regarding Claim 3, Huang discloses wherein, in the 1st-direction cross-section view (Fig. 20E), the width of the upper portion (362; Fig. 20E;¶ 0065) is substantially uniform along the vertical downward direction (Fig. 20E; ¶ 0065 “362 has a substantially constant width”), and the width of the lower portion increases along the vertical downward direction (Fig. 20E; ¶ 0065 “366 tapers from the second portion 364 toward the first portion 362” and “366 has tapered sidewalls 366s”).
Regarding Claim 4, Huang discloses wherein, in the 1st-direction cross-section view (Fig. 20E), the backside contact structure (360, 362, 364, 366; Fig. 20E; ¶ 0065) comprises a side surface (366s; Fig. 20E; ¶ 0066) in a positive slope from a bottom surface thereof (Fig. 20E; ¶ 0066 “the angle θ2 is greater than about 140 degrees and less than about 180 degrees”).
Regarding Claim 5, Huang discloses wherein, in the 1st-direction cross-section view (Figs. 20E), the backside contact structure does not comprise a side surface (362s, 366s, 364s; Fig. 20E; ¶ 0066) in a negative slope from the bottom surface thereof (¶ 0065 “angle θ1 is greater than about 140 degrees and less than about 180 degrees” and “angle θ2 is greater than about 140 degrees and less than about 180 degrees”).
Regarding Claim 6, Huang does not disclose wherein, in the 2nd-direction cross-section view, two opposite side surfaces of the backside contact structure are vertically plane.
Chang discloses wherein, in the 2nd-direction cross-section view (Fig. 27B), two opposite side surfaces of the backside contact structure (the left side surface and the right side surface of the backside contact structure 130 from silicide 129 to the upper portion of STI 68) are vertically plane (Fig. 27B).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention for Huang to have wherein, in the 2nd-direction cross-section view, two opposite side surfaces of the backside contact structure are vertically plane, as taught by Chang, to “reduce RC time delay” and “improve device performance” (Chang ¶ 0097).
Regarding Claim 7, Huang discloses further comprising a backside isolation structure (330, Figs. 20B-20E; ¶ 0056) surrounding the backside contact structure (Figs. 20B-20E; ¶ 0056); and
a backside metal line (370, 372, 374; Figs. 20B-20C, 21B-21C; ¶ 0063 “backside multilayer interconnection (MLI) 370” and “backside MLI 370 includes vertical interconnects, such as vias or contacts 372, and horizontal interconnects, such as metal lines 374”) on the lower portion of the backside contact structure (360, 362, 364, 366) opposite the at least one of the source/drain regions (Figs. 20B-20C, 21B-21C; ¶ 0063 “backside multilayer interconnection (MLI) 370 including metal layers and inter-metal dielectric (IMD) is formed over the isolation structure 130”), wherein the backside metal line is distinct from the backside contact structure (Figs. 20B-20C, 21B-21C; ¶ 0063 “backside multilayer interconnection (MLI) 370 including metal layers and inter-metal dielectric (IMD) is formed over the isolation structure 130”).
Regarding Claim 8, Huang discloses a semiconductor device (Figs. 21A-D; ¶ 0005-0008) comprising:
a channel structure (124; Fig. 21B; ¶ 0043 “124 are referred to as channels of the semiconductor device”);
source/drain regions (230, 240; Fig. 21B; ¶ 0064 “S/D epitaxial structures (e.g., the top epitaxial structures 240 and/or the bottom epitaxial structures 230) as sources and/or drains”) connected by the channel structure (¶ 0064 “S/D epitaxial structures are electrically connected to the second semiconductor layers 124”);
a backside contact structure (360, 362, 364, 366; Figs. 20E, 21B-21C; ¶ 0065) below at least one of the source/drain regions (¶ 0062 “backside via 360 is electrically connected to the etched top epitaxial structure 240”, ¶ 0064 “backside via 360 is connected to the backside of one of the S/D epitaxial structures”),
wherein the backside contact structure comprises an upper portion (362; Fig. 20E; ¶ 0065 “backside via 360 includes a first portion 362”) having a first interface with the at least one of the source/drain regions (Fig. 20E; ¶ 0062 “backside via 360 is…formed…above the backside metal alloy layer 350” “As such, the backside via 360 is electrically connected to the etched top epitaxial structure 240.”) and a lower portion (364; Fig. 20E; ¶ 0065 “backside via 360 includes…a second portion 364”) having a second interface opposite the first interface (Fig. 20E; ¶ 0065 “first portion 362 is closer to the top epitaxial structure 240 than the second portion 364”); and
a backside metal line (370, 372, 374; Figs. 20B-20C, 21B-21C; ¶ 0063 “backside multilayer interconnection (MLI) 370” and “backside MLI 370 includes vertical interconnects, such as vias or contacts 372, and horizontal interconnects, such as metal lines 374”) on the lower portion of the backside contact structure (360, 362, 364, 366) opposite the at least one of the source/drain regions (Figs. 20B-20C, 21B-21C; ¶ 0063 “backside multilayer interconnection (MLI) 370 including metal layers and inter-metal dielectric (IMD) is formed over the isolation structure 130”), wherein the backside metal line is distinct from the backside contact structure (Figs. 20B-20C, 21B-21C; ¶ 0063 “backside multilayer interconnection (MLI) 370 including metal layers and inter-metal dielectric (IMD) is formed over the isolation structure 130”),
wherein, in a 1st-direction cross-section view (Figs. 20A, 20B, 20E; ¶ 0063, 0065-0066), the backside contact structure (360, 362, 364, 366; Fig. 20E; ¶ 0065) comprises a side surface (366s; Fig. 20E; ¶ 0066) in a positive slope from a bottom surface thereof (Fig. 20E; ¶ 0066 “the angle θ2 is greater than about 140 degrees and less than about 180 degrees”).
Huang does not disclose
wherein, in a 2nd-direction cross-section view, widths of the upper portion of the backside contact structure along the first interface and the lower portion of the backside contact structure along the second interface are substantially uniform with each other along a vertical downward direction, and
wherein the 1st direction intersects the 2nd direction.
Chang discloses
wherein, in a 2nd-direction cross-section view (Fig. 27B; ¶ 0096), widths of the upper portion (Fig. 27B the upper portion of backside contact structure 130 physically contacting and electrically coupled to silicide region 129 of source/drain region 92, as marked in the annotated Fig. 27B supra; ¶ 0096) of the backside contact structure (130; Fig. 27B; ¶ 0096 “backside vias 130”) along the first interface (Fig. 27B; ¶ 0096 “backside vias 130 are electrically coupled to the first epitaxial source/drain regions 92 through the second silicide regions 129”) and the lower portion (Fig. 27B the lower portion of backside contact structure 130 in STI region 68, as marked in the annotated Fig. 27B supra) of the backside contact structure along the second interface (Fig. 27B the lower portion of 130 in STI region 68 is a second interface opposite the first interface; ¶ 0096) are substantially uniform with each other along a vertical downward direction (Fig. 27B; ¶ 0096), and
wherein the 1st direction intersects the 2nd direction (Fig. 1; ¶ 0013-0015).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention for Huang to have wherein, in a 2nd-direction cross-section view, widths of the upper portion of the backside contact structure along the first interface and the lower portion of the backside contact structure along the second interface are substantially uniform with each other along a vertical downward direction, and wherein the 1st direction intersects the 2nd direction, as taught by Chang, to “reduce RC time delay” and “improve device performance” (Chang ¶ 0097).
Regarding Claim 9, Huang discloses wherein, in the 1st-direction cross-section view (Fig. 20E), a width (W1; Fig. 20E; ¶ 0065) of the upper portion (362; Fig. 20E; ¶ 0065) of the backside contact structure is smaller than (Fig. 2E; ¶ 0065 “width W1 of the first portion 362 is less than a width W2 of the second portion 364”) a width (W2; Fig. 2E; ¶ 0065) of the lower portion (364; Fig. 2E; ¶ 0065) of the backside contact structure.
Regarding Claim 10; Huang does not disclose wherein, in the 2nd-direction cross-section view, the width of the upper portion of the backside contact structure is substantially equal to the width of the lower portion of the backside contact structure.
Chang discloses wherein, in the 2nd-direction cross-section view (Fig. 27B), the width of the upper portion (Fig. 27B the upper portion of backside contact structure 130 in STI region 68) of the backside contact structure is substantially equal to the width of the lower portion (Fig. 27B the lower portion of backside contact structure 130 electrically coupled to silicide region 129 of source/drain region 92; ¶ 0096) of the backside contact structure.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention for Huang to have wherein, in the 2nd-direction cross-section view, the width of the upper portion of the backside contact structure is substantially equal to the width of the lower portion of the backside contact structure, as taught by Chang, to “reduce RC time delay” and “improve device performance” (Chang ¶ 0097).
Regarding Claim 11, Huang discloses wherein, in the 1st-direction cross-section view (Figs. 20E), the backside contact structure does not comprise a side surface (362s, 366s, 364s; Fig. 20E; ¶ 0066) in a negative slope from the bottom surface thereof (¶ 0065 “angle θ1 is greater than about 140 degrees and less than about 180 degrees” and “angle θ2 is greater than about 140 degrees and less than about 180 degrees”).
Regarding Claim 12, Huang does not disclose wherein, in the 2nd-direction cross-section view, two opposite side surfaces of the backside contact structure are vertically plane.
Chang discloses wherein, in the 2nd-direction cross-section view (Fig. 27B), two opposite side surfaces of the backside contact structure (the left side surface and the right side surface of the backside contact structure 130 from silicide 129 to the upper portion of STI 68) are vertically plane (Fig. 27B).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention for Huang to have wherein, in the 2nd-direction cross-section view, two opposite side surfaces of the backside contact structure are vertically plane, as taught by Chang, to “reduce RC time delay” and “improve device performance” (Chang ¶ 0097).
Regarding Claim 13, Huang discloses further comprising a backside isolation structure (330, Figs. 20B-20E; ¶ 0056) surrounding the backside contact structure (Figs. 20B-20E; ¶ 0056).
Response to Arguments
In their amendment and response dated 6/12/2026, the applicant states (page 10) that Chang and Huang fail to disclose or suggest the recitations of Claim 1.
The amendments to Claim 1, and its dependent Claim 7, has necessitated an updated rejection of Claims 1 and 7 over Huang and Chang, as discussed supra.
The applicant states (page 10) states “Claim 8 includes similar recitations, and thus Claim 9 and the claims dependent therefrom are patentable for at least similar reasons.”
The amendments to independent Claim 8 has necessitated an updated rejection of Claim 8 over Huang and Chang, as discussed supra.
Independent Claims 1 and 8 are rejected for at least the reasons stated supra. Dependent Claims 2-7 and 9-13 are rejected for at least the reasons stated supra.
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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/R.K./Examiner, Art Unit 2818
/JEFF W NATALINI/Supervisory Patent Examiner, Art Unit 2818
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