DETAILED ACTION
Claim Rejections - 35 USC § 112
The following is a quotation of the first paragraph of 35 U.S.C. 112(a):
(a) IN GENERAL.—The specification shall contain a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the same, and shall set forth the best mode contemplated by the inventor or joint inventor of carrying out the invention.
The following is a quotation of the first paragraph of pre-AIA 35 U.S.C. 112:
The specification shall contain a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the same, and shall set forth the best mode contemplated by the inventor of carrying out his invention.
Claims 20, 22-23, and 25 are rejected under 35 U.S.C. 112(a) or 35 U.S.C. 112 (pre-AIA ), first paragraph, as failing to comply with the written description requirement. The claim(s) contains subject matter which was not described in the specification in such a way as to reasonably convey to one skilled in the relevant art that the inventor or a joint inventor, or for applications subject to pre-AIA 35 U.S.C. 112, the inventor(s), at the time the application was filed, had possession of the claimed invention.
Regarding claims 20 and 23, limitations “the number of all of the basal plane dislocations in the drift layer has been identified, and the number of all of the basal plane dislocations in the high-concentration epitaxial layer has been identified” in claim 20 and “the positions of all of the basal plane dislocations in the high-concentration epitaxial layer have identified” in claim 23 introduce new matter issues into the claims since these limitations were not described in the Specification of the instant application with reasons as follow [underlying for clarity]:
First, while Applicant alleges that support for such amendments in claim 20 and 23 dated in 07/02/2025 is found in the original claims (Remarks dated 07/02/2025, page 1) and paragraphs 52-53 (Remarks dated 12/03/2025, page 1), neither the original claims nor paragraphs 52-53 in the Specification support such amendments (See claims 1-17 dated 03/29/2022 in the instant application and paragraphs 52-53).
Second, while the Specification describes a method/step of evaluating whether or not basal plane dislocations (BPDs) are present in the epitaxial layer having an impurity concentration of 1×1018 cm−3 or more (For example, Figs. 5-6 showing only one BPD), the Specification does not explicitly describe all of number/position of BPDs identified in the epitaxial layer having the impurity concentration of 1×1018 cm−3 or more and/or in the drift layer. It is also noted that Figures alone in the instant application do not support such amendments either since only portion of the surface of the epitaxial layer having the impurity concentration of 1×1018 cm−3 or more for the SiC epitaxial wafer is shown in the drawings and, therefore, prevent from knowing all of number/position of the BPDs in the epitaxial layer and/or in the drift layer. As such, the limitations in claims 20 and 23 introduce new matter issues into the claims.
Claims 22 and 25, which depend from claims 20 and 23, respectively, are also rejected by virtue of their dependencies.
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, 5-6, 9-12, 15, and 18-25 are rejected under 35 U.S.C. 103 as being unpatentable over Momose et al. (US 2011/0006309 A1; hereinafter “Momose”) in view of Tanaka et al. (US 2019/0145021 A1; hereinafter “Tanaka”).
Regrading claim 1, Momose teaches a SiC epitaxial wafer, comprising a high-concentration epitaxial layer having an impurity concentration of 1×1018 cm−3 or more (a SiC epitaxial film 2 having a doping concentration of 1×1019 cm−3) (Figs. 4-5 and paragraphs 95 and 118), and wherein the number of basal plane dislocations included in the high-concentration epitaxial layer has been identified (Fig. 5 and paragraph 119 at least disclosing “basal plane dislocations which are primarily of the three types (a) to (c) are generated in the epitaxial film 2”).
Momose does not explicitly teach a drift layer which has a lower impurity concentration than that of the high-concentration epitaxial layer. Tanaka teaches a SiC epitaxial wafer for a SiC semiconductor device such as a power device (Figs. 1-2 and paragraphs 25-31), comprising: a drift layer which has a lower impurity concentration (a drift layer 11 having an impurity concentration of 1×1017 cm−3) than that of a high-concentration epitaxial layer (a second epitaxial layer 42 having an impurity concentration 1×1019 cm−3) (Figs. 1-2 and paragraphs 30-31 and 62). Tanaka teaches that the drift layer is provided depends on the various required properties for the power device (Figs. 1-2 and paragraphs 25-31). Therefore, it would have been obvious to one of ordinary skill in the art to combine the teaching of Momose with that of Tanaka in order to provide the drift layer having the various required properties for the power device.
Regrading claim 5, Momose teaches a SiC epitaxial wafer, comprising a high-concentration epitaxial layer having an impurity concentration of 1×1018 cm−3 or more (a SiC epitaxial film 2 having a doping concentration of 1×1019 cm−3) (Figs. 4-5 and paragraphs 95 and 118), and wherein positions of basal plane dislocations included in the high-concentration epitaxial layer has been identified (Fig. 5 and paragraph 119 at least disclosing “basal plane dislocations which are primarily of the three types (a) to (c) are generated in the epitaxial film 2”).
Momose does not explicitly teach a drift layer which has a lower impurity concentration than that of the high-concentration epitaxial layer. Tanaka teaches a SiC epitaxial wafer for a SiC semiconductor device such as a power device (Figs. 1-2 and paragraphs 25-31), comprising: a drift layer which has a lower impurity concentration (a drift layer 11 having an impurity concentration of 1×1017 cm−3) than that of a high-concentration epitaxial layer (a second epitaxial layer 42 having an impurity concentration 1×1019 cm−3) (Figs. 1-2 and paragraphs 30-31 and 62). Tanaka teaches that the drift layer is provided depends on the various required properties for the power device (Figs. 1-2 and paragraphs 25-31). Therefore, it would have been obvious to one of ordinary skill in the art to combine the teaching of Momose with that of Tanaka in order to provide the drift layer having the various required properties for the power device.
Regarding claim 6, while Momose in view of Tanaka does not explicitly teach that the SiC epitaxial wafer has a diameter of 6-inch or more as claimed, it would have been obvious to one of ordinary skill in the art to utilize the SiC epitaxial wafer having the diameter 6-inch or greater in order to produce high density semiconductor devices from the SiC epitaxial wafer having large diameter.
Regrading claims 9-12, it is noted that each of claims 9-10 reciting “the SiC epitaxial wafer is manufactured by a method…stacking the drift layer on the high-concentration epitaxial layer” and each of claims 11-12 reciting “the number of the basal plane dislocations included in the high-concentration epitaxial layer has been identified by an evaluation method…to identify the number of the basal plane dislocations included in the high-concentration epitaxial layer” is a product-by process claim and therefore is treated according to MPEP 2113. Even through product-by process claims are limited by and defined by the process, determination of patentability is based on the product itself. The patentability of a product does not depend on its method of production. Since Momose in view of Tanaka teaches each and every limitation of the SiC epitaxial wafer comprising the high-concentration epitaxial layer and the drift layer as discussed above, the claimed method (“the SiC epitaxial wafer is manufactured by a method” in claims 9-10 and “the number of the basal plane dislocations included in the high-concentration epitaxial layer has been identified by an evaluation method” in claims 11-12) does not distinguish from the prior art.
Regrading claim 15, Tanaka teaches wherein the drift layer is stacked on the high-concentration epitaxial layer (Fig. 2 and paragraphs 29-30).
Regrading claim 18, Momose in view of Tanaka teaches a SiC epitaxial wafer, comprising a SiC substrate (a SiC single crystal wafer 1) (Momose, Figs. 4-5 and paragraph 118), wherein the high-concentration epitaxial layer is located on the SiC substrate (Momose, Figs. 4-5), the drift layer is located on the high-concentration epitaxial layer (Tanaka, Fig. 2), and the number of the basal plane dislocations in the high-concentration epitaxial layer is larger than that of the drift layer (Tanaka, paragraphs 17-18 and 49, the third epitaxial layer 43, which is the drift layer 11, having reduced basal plane dislocations).
Regrading claim 19, Momose in view of Tanaka teaches a SiC epitaxial wafer, comprising a SiC substrate (a SiC single crystal wafer 1) (Momose, Figs. 4-5 and paragraph 118), wherein the high-concentration epitaxial layer is located on the SiC substrate (Momose, Figs. 4-5), the drift layer is located on the high-concentration epitaxial layer (Tanaka, Fig. 2), and presence or absence of the basal plane dislocations in the high-concentration epitaxial layer and positions of the basal plane dislocations in the high-concentration epitaxial layer have been identified (Momose, Fig. 5 and paragraph 119 at least disclosing “basal plane dislocations which are primarily of the three types (a) to (c) are generated in the epitaxial film 2”).
Regrading claim 20, Momose in view of Tanaka teaches wherein the number of all of the basal plane dislocations in the drift layer has been identified (Momose, Fig. 5 and Tanaka, paragraphs 17-18 and 41-49 teaching the third epitaxial layer 43, which is the drift layer 11, having reduced basal plane dislocations is considered all of the basal plane dislocations in the drift layer), and the number of all of the basal plane dislocations in the high-concentration epitaxial layer has been identified (Momose, Fig. 5 and paragraph 119, a number of basal plane dislocations (epi-BPD) included in 2 has been identified as shown in Fig. 5).
Regrading claim 23, Momose in view of Tanaka teaches wherein the number of the basal plane dislocations in the high-concentration epitaxial layer has been identified (Momose, Fig. 5 and paragraph 119), and the position of all of the basal plane dislocations in the high-concentration epitaxial layer has been identified (Momose, Fig. 5 and paragraph 119 at least disclosing “basal plane dislocations which are primarily of the three types (a) to (c) are generated in the epitaxial film 2”).
Regrading claims 21-22 and 24-25, Tanaka teaches further comprising a buffer layer which has an impurity concentration (41 having an impurity concentration 1×1019 cm−3) equal to or lower than that of the high-concentration epitaxial layer (42 having the impurity concentration 1×1019 cm−3) and is located between a SiC substrate (a silicon carbide single-crystal substrate 10) and the high-concentration epitaxial layer (42) (Fig. 2 and paragraphs 17 and 62).
Affidavit or Declaration Under 37 CFR 1.132
The declaration under 37 CFR 1.132 filed 06/16/2026 is insufficient to overcome the rejection of at least claim 1 based upon Momose et al. (US 2011/0006309 A1) in view of Tanaka et al. (US 2019/0145021 A1) under 35 U.S.C. 103 as set forth in the last Office action because: facts/arguments presented are not germane to the rejection at issue with reasons as follow:
First, the arguments/facts in paragraph 4 of the declaration would fail to set forth facts that the high concentration epitaxial layer could not be identified as claimed at the time of filing Momose since Momose in fact explicitly labels and depicts the basal plane dislocations (BPDs) and clearly describes at least that “basal plane dislocations which are primarily of the three types (a) to (c) are generated in the epitaxial film 2” (See Fig. 5 and paragraph 119), which would be considered as identifying the BPDs as claimed, even if the declarant alleges that the drawing is schematic diagram illustrating estimated BPDs.
Second, the limitations at issue are “the number of basal plane dislocations included in the high-concentration epitaxial layer has been identified” in claim 1 and “positions of basal plane dislocations included in the high-concentration epitaxial layer have been identified” in claim 5, which require neither a specific number/position of the BPDs nor a specific method step to identify the BPDs. In other words, the features upon which the declarant relies (i.e., the specific number/position of the BPDs or the specific method step to identify the BPDs) are not recited in the rejected claim(s). Although the claims are interpreted in light of the specification, limitations from the specification are not read into the claims. See In re Van Geuns, 988 F.2d 1181, 26 USPQ2d 1057 (Fed. Cir. 1993).
Third, while dependent claims 11 and 12, which depend from claim 1, recite an evaluation method to identify the BPDs, the limitation at issue in a SiC epitaxial wafer in claims 1 and 5 as a product claim would not provide any structural difference compared to Momose in view of Tanaka since the limitations at issue would be also directed to a product-by-process limitation according to MPEP 2113. In other words, with Momose in view of Tanaka teaching each and every limitation of the SiC epitaxial wafer as the product claim comprising the high-concentration epitaxial layer with the impurity concentration and the drift layer as discussed above, the limitations at issues as the claimed product-by-process limitation would not distinguish from Momose in view of Tanaka.
In view of the foregoing, when all of the evidence is considered, the totality of the rebuttal evidence of nonobviousness fails to outweigh the evidence of obviousness.
Response to Arguments
Applicant’s arguments with respect to amended claims to overcome the rejection under 35 U.S.C. 112(a) have been considered but are moot in view of different grounds of rejections as set forth above in this Office Action. Furthermore, it is noted that claims 20 and 23 are not fully amended to delete “all of” to overcome the rejection under 35 U.S.C. 112(a) as Applicants stated. Accordingly, a portion of previous rejection under 35 U.S.C. 112(a) is repeated as discussed 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.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to DANIEL B WHALEN whose telephone number is (571)270-3418. The examiner can normally be reached on M-F: 8AM-5PM.
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/DANIEL WHALEN/Primary Examiner, Art Unit 2893
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