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 .
Continued Examination Under 37 CFR 1.114
A request for continued examination under 37 CFR 1.114, including the fee set forth in 37 CFR 1.17(e), was filed in this application after final rejection. Since this application is eligible for continued examination under 37 CFR 1.114, and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114. Applicant's submission filed on 12/03/2025 has been entered.
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 1, 5-6, 9-12, 15, and 18-27 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 claim 1, the amended limitation “wherein the number of basal plane dislocations included in the high-concentration epitaxial layer has been non-destructively determined” introduces new matter into the claim since this limitation was not described in the original specification of the instant application [underlying for clarity]. Particularly, Applicant alleges that support for such amended limitation is found in Figs. 1-4 and accompanying descriptions (Remarks, page 1). However, Figs. 1-4 and the accompanying descriptions in the Specification (or any other section in the Specification) do not explicitly describe that the basal plane dislocations in the high-concentration epitaxial layer is in fact “non-destructively determined”. Furthermore, one of ordinary skill in the art would not able to determine that the basal plane dislocations are either destructed (i.e., damaged beyond repair or to ruin the structure by Merriam-Webster Dictionary) or not destructed by merely looking at Figs. 1-4 in the instant application. As such, amended limitation in claim 1 introduces new matter.
Claims 5, 11-12, 19-20, and 23 similarly reciting non-destructive determination (“non-destructively determined”) of the basal plane dislocations are also rejected with the similar reason for rejecting claim 1 as discussed above. Furthermore, claims 5-6, 9-12, 15, and 18-27, which depend from claim 1, are also rejected by virtue of their dependencies.
Regarding claims 5, 20, and 23, amended limitations “positions of all of the basal plane dislocations included in the high-concentration epitaxial layer have been non-destructively determined” in claim 5, “the number of all of the basal plane dislocations in the drift layer has been non-destructively determined, and the number of all of the basal plane dislocations in the high-concentration epitaxial layer has been non-destructively determined” in claim 20, and “wherein the number of all of the basal plane dislocations in the high-concentration epitaxial layer has been non-destructively determined, and the positions of all of the basal plane dislocations in the high-concentration epitaxial layer have been non-destructively determined” 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 claims 5, 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 5, 20, and 23 introduce new matter issues into the claims.
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, 9-12, 15, and 18-27 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 non-destructively determined (Fig. 5 and paragraph 119, the number of basal plane dislocations (epi-BPD) included in 2 has been non-destructively determined as shown in Fig. 5. It is noted that the claimed term “non-destructively determined”, which is currently rejected under 35 USC. 112(a) as discussed above, is considered as a characteristic by looking at Fig. 5 of Momose similar to how Figs. 1-4 are shown in the instant application).
However, 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 wherein positions of all of the basal plane dislocations included in the high-concentration epitaxial layer have been non-destructively determined (Fig. 5 and paragraph 119, positions of all of the basal plane dislocations (epi-BPD) included in 2 have been non-destructively determined as shown in Fig. 5).
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 non-destructively determined by an evaluation method…to non-destructively determine 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 non-destructively determined 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 non-destructively determined (Momose, Fig. 5 and paragraph 119, presence or absence of the basal plane dislocations (epi-BPD) in 2 and positions of the basal plane dislocations (epi-BPD) have been non-destructively determined as shown in Fig. 5).
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 non-destructively determined (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 non-destructively determined (Momose, Fig. 5 and paragraph 119, a number of basal plane dislocations (epi-BPD) included in 2 has been non-destructively determined as shown in Fig. 5).
Regrading claim 23, Momose in view of Tanaka teaches wherein the number of all of the basal plane dislocations in the high-concentration epitaxial layer has been non-destructively determined (Momose, Fig. 5), and the position of all of the basal plane dislocations in the high-concentration epitaxial layer has been non-destructively determined (Momose, Fig. 5, a position of basal plane dislocations (epi-BPD) included in 2 has been non-destructively determined as shown in Fig. 5).
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).
Regrading claim 26, Momose teaches wherein information or a document which specifies the number of basal plane dislocations in the high-concentration epitaxial layer has been provided (Fig. 5 and paragraph 119, information about the number of basal plane dislocations (epi-BPD) included in 2 has been provided as shown in Fig. 5).
Regrading claim 27, Momose teaches wherein information or a document which specifies the positions of basal plane dislocations in the high-concentration epitaxial layer has been provided (Fig. 5 and paragraph 119, information about the positions of basal plane dislocations (epi-BPD) included in 2 have been provided as shown in Fig. 5).
Claim 6 is rejected under 35 U.S.C. 103 as being unpatentable over Momose in view of Tanaka.
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.
Response to Arguments
Applicant’s arguments with respect to amended claims have been considered but are moot in view of new grounds of rejection as set forth above in this Office Action.
Furthermore, Applicant's arguments in response to the rejection of claims 5, 20, and 23 under 35 U.S.C. 112(a) filed 12/03/2025 have been fully considered but they are not persuasive.
Applicant argues that support is in paragraphs 52-53 in the Specification of the instant application (Remarks, page 1-2). Then, after reviewing paragraphs 52-53, Applicant alleges that one of ordinary skill in the art would have understand that all of the basal plane dislocations are identified/determined. Lastly, Applicant concludes that the limitation in the claims are therefore not indefinite. These argument are not found persuasive since 1) paragraphs 52-53 do not explicitly describe that all of the basal plane dislocations are identified during the evaluation method as discussed above in the rejection (See the rejection of claims 5, 20, and 23 under 35 U.S.C. 102(a)(1) as discussed above), 2) there is no support in paragraphs 52-53 to suggest or to rephrase that the all of the basal plane dislocations are identified during the evaluation method, and 3) the rejection of claims 5, 20, and 23 under 35 U.S.C. 102(a)(1) is due to the introduction of new matter, not because of indefinite issue as Applicant argues. Therefore, the rejection of claims 5, 20, and 23 are maintained.
Conclusion
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/DANIEL WHALEN/Primary Examiner, Art Unit 2893