DETAILED ACTION
Notice of Pre-AIA or AIA Status
The present application is being examined under the pre-AIA first to invent provisions.
Information Disclosure Statement
The IDS filed on 04/23/2024 and 05/20/2025 have been considered.
Specification
The title of the invention is not descriptive. A new title is required that is clearly indicative of the invention to which the claims are directed.
The following title is suggested: Isolation structures in transistor devices comprising an inner shallow trench isolation region and method for forming.
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.
Claim(s) 8-10 and 12 is/are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Li et al. (U.S. Pub. 2023/0290853).
In re claim 8, Li discloses a device 100 comprising a semiconductor fin (106N,106P) (see paragraph [0023] and fig. 1A); a plurality of nanostructures (124,126) over the semiconductor fin (106N,106P) (see paragraph [0023] and fig. 1B); first 110N and second 110P source/drain regions in the semiconductor fin, the plurality of nanostructures (124,126) extending between the first 110N and second 110P source/drain regions (see paragraph [0023] and fig. 1B); a shallow trench isolation (STI) region 108C along a sidewall of the semiconductor fin (106N,106P) (see paragraph [0025] and fig. 1C); a nitride liner 108B under the STI region 108C, the nitride liner 108B covering a bottom surface and sidewalls of the STI region 108C (see paragraph [0027] and fig. 1C); a nitride hard mask 116A over the STI region 108C, the nitride hard mask 116A covering a top surface of the STI region 108C (see paragraph [0037] and figs. 1C and 1D, note that, element 116A can include SiN, SiCN, or SiOCN and thus constitutes a nitride hard mask); and a gate structure 134 surrounding the plurality of nanostructures (124,126), the gate structure 134 overlapping a first portion of the nitride hard mask 116A (see paragraph [0033] and fig. 1D).
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In re claim 9, as applied to claim 8 above, Li discloses wherein the device further comprising an oxide liner 108A under the nitride liner 108B, the oxide liner 108A covering the bottom surface and sidewalls of the STI region 108C (see paragraph [0027] and fig. 1D).
In re claim 10, as applied to claim 8 above, Li discloses wherein the device further comprising a dielectric layer (130N,130P) around the gate structure 134, the dielectric layer (130N,130P) overlapping a second portion of the nitride hard mask (see paragraph [0033] and fig. 1D).
In re claim 12, as applied to claim 8 above, Li discloses wherein the nitride hard mask 116A has a different material composition than the nitride liner 108B (see paragraphs [0026], [0037]).
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) 1-3, 5, and 14-17 is/are rejected under 35 U.S.C. 103 as being unpatentable over Li et al. (U.S. Pub. 2023/0290853).
In re claim 1, Li discloses a device 100, comprising a first semiconductor fin 106N and a second semiconductor fin 106P (see paragraph [0023] and figs. 1A and 1B); an isolation structure 108 between the first semiconductor fin 106N and the second semiconductor fin 106P, the isolation structure 108 comprising an inner shallow trench isolation (STI) region; a first liner layer 108B along sidewalls and a bottom surface of the inner STI region 108C (see paragraph [0025] and fig. 1D); and a STI hard mask 116A on a top surface of the inner STI region 108C; a plurality of nanostructures (124,126) over the first semiconductor fin (106N,106P) (see paragraph [0033] and fig. 1D); and a gate structure 134 over the isolation structure and the first semiconductor fin (106N,106P), wherein the gate structure 134 surrounds each of the plurality of nanostructures (124,126) (see paragraph [0033] and fig. 1D).
With respect to the limitation of “wherein the STI hard mask and the first liner layer each comprise a higher concentration of nitrogen than the inner STI region”, Li discloses that the STI hard mask 116A can include SiO2, SiN, SiCN, or SiOCN, or silicon germanium oxide (see paragraph [0037]), the first liner layer 108B can include a nitride layer such as SiN, SiON, or other suitable nitride layers (see paragraph [0026]), and the inner STI region 108C can include SiO2 layer or other suitable insulating oxide layers (see paragraph [0025]). Therefore, it is respectfully submitted that it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to be motivated to select materials for the STI hard mask 116A and the first liner layer 108B to be SiN whereas the material for the inner STI region to be SiO2 and thus the STI hard mask and the first liner layer which include a SiN would inherently comprises a higher concentration of nitrogen than the inner STI region comprises SiO2 since it has been held to be within the general skill of a worker in the art to select a known material on the basis of it suitability for the intended use as a matter of obvious design choice. In re Leshin, 125 USPQ 416.
In re claim 2, as applied to claim 1 above, Li discloses wherein the isolation structure further comprises a second liner layer 108A along sidewalls and a bottom surface of the inner STI region 108C, wherein the second liner layer 108A is disposed between the first semiconductor fin (106N,106P) and the first liner layer 108B (see paragraph [0027] and fig. 1D).
In re claim 3, as applied to claim 2 above, Li discloses wherein the first liner layer 108B has a higher concentration of nitrogen than the second liner layer 108A (see paragraphs [0025] and [0027]).
In re claim 5, as applied to claim 1 above, Li discloses wherein the first liner layer 108B has a different material composition than the STI hard mask 116A (see paragraphs [0027] and [0037]).
In re claim 14, Li discloses a method comprising etching a trench in a substrate 104 to define a first semiconductor fin 106N and a second semiconductor fin 106P, the trench being disposed between a first semiconductor fin 104N and a second semiconductor fin 106P (see paragraphs [0019], [0023] and fig. 1A); forming a first liner 108B over and along sidewalls of the trench; forming a shallow trench isolation (STI) region 108C over the first liner 108B (see paragraph [0027] and fig. 1D); forming a hard mask 116A over the STI region 108C (see paragraph [0037] and fig. 1D); and forming a gate structure 134 over and along sidewalls of the first semiconductor fin 106N, wherein the gate structure 134 covers at least a portion of the hard mask 116A (see paragraph [0033] and fig. 1D).
With respect to the limitation of “wherein a first material of the hard mask and a second material of the first liner have etch selectivity to a third material of the STI region”, Li discloses wherein the hard mask 116A can include SiO2, SiN, SiCN, or SiOCN, or silicon germanium oxide (see paragraph [0037]), the first liner 108B can include a nitride layer such as SiN, SiON, or other suitable nitride layers (see paragraph [0026]), and the STI region 108C can include SiO2 layer or other suitable insulating oxide layers (see paragraph [0025]). It is respectfully submitted that it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to be motivated to select materials for the hard mask 116A and the first liner 108B to be SiN whereas the material for the STI region to be SiO2 and thus a first material of the hard mask and a second material of the first liner would inherently have etch selectivity to a third material of the STI region since it has been held to be within the general skill of a worker in the art to select a known material on the basis of it suitability for the intended use as a matter of obvious design choice. In re Leshin, 125 USPQ 416.
In re claim 15, as applied to claim 14 above, Li discloses wherein the first liner 108B and the hard mask 116A each have a higher concentration of nitrogen than the STI region 108C (see paragraphs [0025], [0037]).
In re claim 16, as applied to claim 14 above, Li discloses wherein forming the first liner 108B and forming the STI region 108C comprises depositing a first liner layer over and along sidewalls of the trench; depositing an insulating material over the first liner layer; and after depositing the insulating material, etching back the first liner layer to form the first liner and etching back the insulating material to form the STI region (see paragraph [0037] and fig. 1D).
In re claim 17, as applied to claim 16 above, Li discloses wherein forming the hard mask 116A comprises forming the hard mask after etching back the first liner layer to form the first liner 108B and etching back the insulating material to form the STI region 108C (see paragraphs [0037]).
Claim(s) 4 is/are rejected under 35 U.S.C. 103 as being unpatentable over Li et al. (U.S. Pub. 2023/0290853), as applied to claim 2 above, and further in view Chen et al. (U.S. Pub. 2019/0157156).
In re claim 4, as applied to claim 2 above, Li is silent to wherein the second liner layer comprises: a silicon liner layer; and an oxide liner layer over the silicon liner layer.
However, Chen discloses in a same field of endeavor, a device, including, inter-alia, wherein the second liner layer comprises a silicon liner layer 122; and an oxide liner layer 123 over the silicon liner layer 122 (see paragraphs [0037], [0038] and fig. 2I).
Therefore, it is respectfully submitted that it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to be motivated to incorporate the technique as taught by Chen into the device of Li in order to enable wherein the second liner layer comprises: a silicon liner layer; and an oxide liner layer over the silicon liner layer in Li to be formed in order to enhance the reliability of the semiconductor device (see paragraph [0016] of Chen). Additionally, it has been held to be within the general skill of a worker in the art to select a known material on the basis of it suitability for the intended use as a matter of obvious design choice. In re Leshin, 125 USPQ 416.
Claim(s) 6 and 7 is/are rejected under 35 U.S.C. 103 as being unpatentable over Li et al. (U.S. Pub. 2023/0290853), as applied to claim 1 above, and further in view Lee et al. (U.S. Pub. 2019/0080908).
In re claim 6, as applied to claim 1 above, Li is silent to wherein the STI hard mask has a nitrogen concentration in a range of 28 at % to 38 at %.
However, Lee discloses in a same field of endeavor, a device including, inter-alia, wherein the STI hard mask has a nitrogen concentration in a range of 15 at % to 25 at % (see paragraph [0021]).
Therefore, it is respectfully submitted that it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to be motivated to incorporate the technique as taught by Lee into the device of Li in order to optimize the nitrogen concentration in the STI hard mask during routine experimentation to be in a range of 28 at % to 38 at % since it is not inventive to discover the optimum or workable ranges by routine experimentation. See in re Aller, 220 F.2d 454, 456, 105 USPQ 233 (CCPA 1955). The optimization of the nitrogen concentration range would be obvious to one of ordinary skill in the art.
In re claim 7, as applied to claim 6 above, Li discloses wherein the first liner layer has a nitrogen concentration in a range of 5 at % to 20 at % (see paragraph [0021]) but is silent to wherein the first liner layer has a nitrogen concentration in a range of 4 at % to 14 at %. Thus, the nitrogen concentration range in the first liner layer of Li is overlapping with the nitrogen concentration range of the first liner layer of the claimed invention. Therefore, it is respectfully submitted that it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to be motivated to optimize the nitrogen concentration range of the first liner layer during routine experimentation to be in a range of 4 at % to 14 at % because, absent evidence of disclosure of criticality for the range giving unexpected results, it is not inventive to discover optimal or workable ranges by routine experimentation. In re Aller, 220 F.2d 454, 105 USPQ 233, 235 (CCPA 1955). Furthermore, it appears that these changes produce no functional differences and therefore would have been obvious. See In re Woodruff, 919 F.2d 1575, 1578, 16 USPQ2d 1934, 1936 (Fed. Cir. 1990).
Claim(s) 13 is/are rejected under 35 U.S.C. 103 as being unpatentable over Li et al. (U.S. Pub. 2023/0290853).
In re claim 13, as applied to claim 12 above, Li discloses wherein the nitride hard mask 116A can include SiO2, SiN, SiCN, SiOCN, or silicon germanium oxide (see paragraph [0037]) and the nitride liner 108B can include a nitride layer such as SiN or SiON layer, or other suitable nitride layers (see paragraph [0026]). It is respectfully submitted that it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to select the materials for the nitride hard mask and the nitride layer accordingly, so that the nitrogen concentration of the nitride hard mask is greater than the nitrogen concentration of the nitride liner since it has been held to be within the general skill of a worker in the art to select a known material on the basis of it suitability for the intended use as a matter of obvious design choice. In re Leshin, 125 USPQ 416.
Allowable Subject Matter
Claims 11 and 18-20 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
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure.
Hsiung et al. (U.S. Pub. 2022/0352338) discloses a device including, inter-alia, a first semiconductor fin and a second semiconductor fin 66; an isolation structure 68 between the first semiconductor fin and the second semiconductor fin, the isolation structure 68 comprising an inner shallow trench isolation (STI) region; and a plurality of nanostructures 55 over the first semiconductor fin (see paragraph [0025] and fig. 4); and a gate structure 72 over the isolation structure 68 and the first semiconductor fin 66, wherein the gate structure 72 surrounds each of the plurality of nanostructures 55 (see paragraph [0034] and fig. 5).
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/KHIEM D NGUYEN/Primary Examiner, Art Unit 2892
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