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 .
Applicant's submission filed on 9/1/26 has been entered. Claims 1-3, 6-8, 11, 13, 16-17, and 20 are currently pending examination.
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.
Claim(s) 1-3, 6-8, 11, 13, 16-17, and 20 is/are rejected under 35 U.S.C. 103 as being unpatentable over Liu et. al. (US 2020/0105523; hereafter Liu) in view of Zhou et al (US2020/0350160; hereafter Zhou), Shih et al (US 2008/0203528; hereafter Shih), and Vorsa et al (US 2010/0120262; hereafter Vorsa).
Claims 1 and 6: Liu teaches a method of depositing a compressive nitride film on a bowed semiconductor substrate, (see, for example, abstract, [0033], [0038]) the method comprising:
providing a bowed semiconductor substrate having one or more regions of tensile stress and one or more regions of compressive stress (see, for example, abstract, [0008], [0030]);
and depositing, by plasma-enhanced chemical vapor deposition (PECVD), at a deposition temperature of between about 300oC and 550oC, a compressive nitride film on a backside of the bowed semiconductor substrate, wherein the compressive nitride film has a compressive film stress (see, for example, abstract, [0008], [0030], [0033], [0038], [0055])
wherein the PECVD is performed to deposit the compressive nitride film on the backside of the bowed semiconductor substrate using a LFRF power and a HFRF power (See, for example, abstract, [0016-0017], Table 1, [0057], [0071-77]).
Liu teaches the method above, but is silent as to the value of stress shift of its compressive nitride film, therefore it does not explicitly teach a shift within the claimed range. Zhou teaches a method of depositing a compressive nitride film onto the backside surface of a bowed semiconductor substrate, (see, for example, abstract, [0003-4], [0021][0028-29]). Zhou further teaches wherein retention of stress aids in proper bow compensation, and wherein stress retention at temperatures at and in excess of 850oC, such as 950C are preferably on the order of about 70% (see, for example, [0029] and [0036-38]). Therefore it would have been obvious to one of ordinary skill in the art at the time before the effective filing date of the claimed invention to have incorporated a stress shift of about 30% when the compressive film is exposed to a temperature greater than 850oC since such an order is known in the art to be desirable for adequate mitigation design, since maximizing retention would predictably reduce deviation from target stress compensation goals, and since when a primary reference is silent as to a certain detail, one of ordinary skill would be motivated to consult a secondary reference which satisfies the deficiencies of the primary reference. Although no singular exemplary embodiment is provided at such temperatures and exact exemplary retention values, it would have been obvious to one of ordinary skill in the art at the time before the effective filing date of the claimed invention to have incorporated retention values within the claimed range since in the case where the claimed ranges “overlap or lie inside ranges disclosed by the prior art” a prima facie case of obviousness exists. In re Wertheim, 541 F.2d 257, 191USPQ 90 (CCPA 1976), discovery of an optimum value of a result effective variable in a known process is ordinarily within the skill of the art. In re Boesch, 617 F.2d 272, 276 (CCPA 1980), and since a reasonable expectation of success exists from choosing the specific taught species from explicitly taught lists. Further when the species is clearly named, the species claim is anticipated (rendered obvious) no matter how many other species are additionally named. Ex parte A 17 USPQ2d 1716 (Bd. Pat. App. & Inter. 1990).
Liu further teaches wherein the compressive film stress can be tailorable to the magnitude of the bow of substrate to adequately mitigate it (See, for example, abstract, [0044], [0065]) and Zhou further teaches corrective compressive stress on the order of 1.5 GPa silicon nitride films are suitable for addressing conventional degrees of bowing (See, for example, [0021], [0029]). Therefore it would have been obvious to one of ordinary skill in the art at the time before the effective filing date of the claimed invention to have incorporated a compressive nitride possessing a compressive film stress of about 1.5 GPa since such a magnitude would perform predictably as a backside silicon nitride film to correct bowing issues in the art, and since when a primary reference is silent as to a certain detail, one of ordinary skill would be motivated to consult a secondary reference which satisfies the deficiencies of the primary reference.
Liu further teaches wherein the dual frequency process conditions influence that stress of the deposited film (See, for example, [0057]), but does not explicitly teach wherein the LFRF power is equal to or less than about 20% of a total RF power applied between the LFRF and the HFRF power. Shih teaches a method of depositing PECVD compressive silicon nitride films (See, for example, abstract, [0032-0034]). Shih further teaches wherein such silicon nitride films with compressive stress of greater than 1 GPa, and further nearly 4.5 GPa can be achieved with LFRF power of 100-500W, further 100 W and HFRF power between 630 and 770, further 700 W (LFRF/(LFRF+HFRF) of about 11.5 % to 44%, further with an exemplary ratio of ~12.5% (See, for example, [0033-34]). Therefore it would have been obvious to one of ordinary skill in the art at the time before the effective filing date of the claimed invention to have incorporated an LFRF and HFRF power wherein the LFRF power is equal to or less than about 11.5 % to 44%, of a total RF power applied, further 12.5% since such conditions provide predictable power conditions for achieving compressive stresses in silicon nitride layers on the level desired (~1.5 GPa compressive) and which would perform predictably as a backside silicon nitride film to correct bowing issues in the art. Additionally / optionally with respect to the range of 11.5% to 44% LFRF: total power, although such a range is not explicitly less than about 20% as claimed, it would have been obvious to one of ordinary skill in the art at the time before the effective filing date of the claimed invention to have incorporated a ratio within the claimed range since in the case where the claimed ranges “overlap or lie inside ranges disclosed by the prior art” a prima facie case of obviousness exists. In re Wertheim, 541 F.2d 257, 191USPQ 90 (CCPA 1976)
As the above combination has formed a compressive nitride film by a method involving deposition temperature and LFRF/ HFRF powers, the resulting film stress would intrinsically have been based, at least in part, on said temperatures and powers.
Liu further teaches wherein depositing the compressive nitride film by PECVD comprises: exposing the backside of the bowed semiconductor substrate to a silicon-containing precursor and a nitrogen-containing reactant; and exposing the backside of the bowed semiconductor substrate to plasma to drive a reaction between the silicon-containing precursor and the nitrogen-containing reactant to deposit the compressive nitride film (See, for example, abstract, [0016-0017] [0071-77]).
Liu further teaches flowing a gas mixture comprising a silicon containing precursor and a nitrogen-containing reactant, wherein the process conditions including flow rates influence that stress of the deposited film (See, for example, [0057], [0061]). Liu further teaches wherein a flow rate of silicon-containing precursor, such as silane, is from 1400-2600 sccm, the flow rate of NH3 is from 8400-15600 and the flow rate of N2 is from 8400-15600 sccm, and flow rate of N2 from top of substrate is from 2800-5200 (see, for example, Table 1; wherein by calculation, the ratio of silane to the total gas flow in the PECVD ranges from 3.7 to 11.7 %). Although such a range is not explicitly flow rate of silane equal to or less than about 5% by volume of a total gas mixture in PECVD; it would have been obvious to one of ordinary skill in the art at the time before the effective filing date of the claimed invention to have incorporated such a value within the claimed range since in the case where the claimed ranges “overlap or lie inside ranges disclosed by the prior art” a prima facie case of obviousness exists. In re Wertheim, 541 F.2d 257, 191USPQ 90 (CCPA 1976), and / or discovery of an optimum value of a result effective variable in a known process is ordinarily within the skill of the art. In re Boesch, 617 F.2d 272, 276 (CCPA 1980).
Liu in view of Zhou, and Shih teaches the method above, including embodiments of preparing compressive nitride coatings, Liu further teaches wherein the intended coating is stoichiometric silicon nitride, further undoped / only trace amounts of hydrogen; so intrinsically the number of Si-N bonds within an undoped silicon nitride layer / trace H silicon nitride layer would outnumber N-H bonds (See, for example, [0018], [0046], [0049]). But Liu is silent as to the relative amounts of N-H, Si-H, and Si-N bonds present in the compressive nitride film, so it does not explicitly teach wherein a number of N—H bonds is greater than a number of Si—H bonds in the compressive nitride film. Vorsa teaches a method of PECVD deposition of compressive silicon nitride coatings (see, for example, abstract). Vorsa further teaches wherein a higher ratio of N-H bonds to Si-H bonds correlates to enhanced compressive stress (See, for example, Fig 4), and preferably recommends a ratio of 25 to 85 (See, for example, [0026]). Therefore it would have been obvious to one of ordinary skill in the art at the time before the effective filing date of the claimed invention to have incorporated a number of N—H bonds is greater than a number of Si—H bonds in the compressive nitride film since such a higher number of N-H bonds would predictably enhance the obtainable compressive stress. Vorsa additionally evidences / demonstrates that the number of Si-N bonds in silicon nitride are greater than the number of N-H bonds (see, for example, Fig 3).
Claim 2: Liu further teaches wherein the compressive nitride film is undoped silicon nitride, oxygen-doped silicon nitride, or carbon-doped silicon nitride (see, for example, [0018], [0046], [0049]).
Claim 3: Liu further teaches wherein the compressive nitride film is undoped silicon nitride (see, for example, [0018], [0046], [0049]).
Claim 7: Liu further teaches depositing a tensile nitride film on the backside of the bowed semiconductor substrate, wherein the tensile nitride film is deposited in the one or more regions of compressive stress and the compressive nitride film is deposited in the one or more regions of tensile stress to mitigate bowing on a frontside of the bowed semiconductor substrate. (See, for example, abstract, [0016-0017] [0071-77]).
Claim 8: Liu further teaches wherein depositing the compressive nitride film by PECVD comprises: exposing the backside of the bowed semiconductor substrate to the silicon-containing precursor and the nitrogen-containing reactant; and exposing the backside of the bowed semiconductor substrate to plasma to drive a reaction between the silicon-containing precursor and the nitrogen-containing reactant to deposit the compressive nitride film (See, for example, abstract, [0016-0017] [0071-77]).
Claim 11: Liu further teaches wherein the silicon containing precursor includes silane (See, for example, [0058]).
Claims 13 and 16: refer to the rejections of claims 1-3, 6-8, and 11 over Liu in view of Zhou, Shih, and Vorsa above.
Claim 17: Liu in view of Zhou, Shih, and Vorsa teaches the method of claim 13 above, and Liu further teaches wherein the thickness of the compensation layer is influenced by the magnitude of the bow correction desired (See, for example, [0065]). Zhou similarly teaches wherein backside thickness can be tailored to compensate respective bowing, and further teaches wherein thickness on the order of 0.1 to 1 micron are known in the art to adequately correct varying degrees of bowing (See, for example, [0029] [0040]). Therefore it would have been obvious to one of ordinary skill in the art at the time before the effective filing date of the claimed invention to have incorporated a compressive nitride thickness on the order of 0.1 to 1 micron since such thicknesses achieve the predictable result of correcting degrees of bowing conventional in the art, and since discovery of an optimum value of a result effective variable in a known process is ordinarily within the skill of the art. In re Boesch, 617 F.2d 272, 276 (CCPA 1980). Although 0.1 to 1 micron is not explicitly less than 300 nm, it would have been obvious to one of ordinary skill in the art at the time before the effective filing date of the claimed invention to have incorporated a thickness within the claimed range since in the case where the claimed ranges “overlap or lie inside ranges disclosed by the prior art” a prima facie case of obviousness exists. In re Wertheim, 541 F.2d 257, 191USPQ 90 (CCPA 1976).
Claim 20: Liu further teaches the bowed semiconductor substrate has one or more tensile regions, wherein the silicon nitride film mitigates bowing in the one or more tensile regions of the bowed semiconductor substrate (see, for example, Abstract, [0003], [0017], [0033], [0047] [0056]).
Response to Arguments
Applicant's submission filed 9/1/26 has been fully considered but is not persuasive.
With respect to Applicant’s amended content of claims 1 and 13 derived from previous dependent claims 8, 11, 12 and 19, the examiner has similarly incorporated content from the previous rejections of claims 8, 11, 12 and 19, including the incorporation of Vorsa, as discussed above.
In response to applicant's arguments against the references individually (Zhou uses PVD, not PECVD), one cannot show nonobviousness by attacking references individually where the rejections are based on combinations of references. See In re Keller, 642 F.2d 413, 208 USPQ 871 (CCPA 1981); In re Merck & Co., 800 F.2d 1091, 231 USPQ 375 (Fed. Cir. 1986). The rejection is over a combination of references, not Zhou alone. Zhou is not relied upon for PVD, rather its reliance is upon its teaching that a stress shift of about 30% is a property desirable in art for adequate mitigation design to predictably reduce deviation from target stress compensation goals, and the desirability of a compressive film stress of about 1.5 GPa since such a magnitude would perform predictably as a backside silicon nitride film to correct bowing issues in the art. The benefits of bow mitigation / correction and associated stress shift gleaned from the teaching of the prior art are relevant beyond mode of application and speak to a design target for the resulting material property of a formed silicon nitride film. Primary reference Liu (and now further Shih) has already been relied upon for deposition via PECVD and met the associated claim limitation, thus such PECVD teaching is not similarly requisite to be attributed to Zhou.
In response to applicant's arguments against the references individually (Shih fails to disclose that a number of Si-N bonds is greater than the number of N-H bonds), one cannot show nonobviousness by attacking references individually where the rejections are based on combinations of references. See In re Keller, 642 F.2d 413, 208 USPQ 871 (CCPA 1981); In re Merck & Co., 800 F.2d 1091, 231 USPQ 375 (Fed. Cir. 1986). The rejection is over a combination of references, not Shih alone. Primary reference Liu already teaches wherein the intended coating is stoichiometric silicon nitride, further undoped / only trace amounts of hydrogen; so intrinsically the number of Si-N bonds within an undoped silicon nitride layer / trace H silicon nitride layer would outnumber N-H bonds; otherwise it would not be considered “stoichiometric” / “undoped” “trace”. With respect to the addition of the number of N-H bonds being greater than Si-H bonds, the examiner has incorporated secondary reference Vorsa (refer to rejection). Vorsa additionally evidences / demonstrates that the number of Si-N bonds in silicon nitride are greater than the number of N-H bonds (see, for example, Fig 3).
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.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to NATHAN H EMPIE whose telephone number is (571)270-1886. The examiner can normally be reached Monday-Thursday 5:30AM - 4 PM.
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/NATHAN H EMPIE/Primary Examiner, Art Unit 1712
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