DETAILED ACTION
This Office Action is in response to Amendment filed July 17, 2026.
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Claim Rejections - 35 USC § 112
The following is a quotation of 35 U.S.C. 112(b):
(b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention.
The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph:
The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention.
Claims 6 and 7 are rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention.
(1) Regarding claims 6 and 7, it is not clear how the claimed nitrogen concentration measurements can be performed “at a total of 21 points” as recited on line 8 of claim 6 and on line 4 of claim 7, because (a) Applicants claim “5 points arranged at equal intervals in each of 4 directions of a cross with a center of the SiC epitaxial wafer as an origin” on lines 9-10 of claim 6 and on line 4-5 of claim 7, which suggests that the “21 points” are 21 “points” or 21 zero-dimensional objects with respect to the “center” or “origin”, (b) it is not clear how the nitrogen concentrations can be measured at the 21 zero-dimensional objects since the 21 zero-dimensional objects would contain zero or indefinite nitrogen concentrations due to zero volumes, (c) therefore, the “21 points” should not exactly be 21 zero-dimensional objects, and (d) in this case, it is not clear what the “21 points” refer to, and whether the “21 points” actually have sizes, in which case it is not clear whether the actual sizes of the “21 points” are circular, oval-shaped, square-shaped, rectangular-shaped, etc.
(2) Also regarding claims 6 and 7, it is not clear how “a total 21 points” can “consist of “5 points arranged at equal intervals in each of 4 directions of a cross with a center of the SiC epitaxial wafer as an origin”, because “5 points” in “4 directions” would correspond to a total of 20 points rather than “a total 21 points”.
(3) Further regarding claims 6 and 7, it is not clear what “a center of the SiC epitaxial wafer” recited on lines 9-10 of claim 6 and on line 5 of claim 7 refers to, and whether the limitation implies a symmetrical SiC epitaxial wafer, because (a) as can be clearly seen in Fig. 4 of current application, the SiC epitaxial wafer may not be symmetrical, (b) in this case, the “center” of the SiC epitaxial wafer does not correspond to the measurement point p6 shown in Fig. 4 of current application, but rather corresponds to a point somewhere between the measurement point p5 and the measurement point p6, and (c) therefore, it is not clear what the “center” of the SiC epitaxial wafer refers to, and how it is defined when the SiC epitaxial wafer is not symmetrical.
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 1-3, 5, 7, 9 and 11 are rejected under 35 U.S.C. 103 as being unpatentable over Nakamura et al. (US 2019/0040545)
Regarding claims 1 and 11, Nakamura et al. disclose a SiC epitaxial wafer (Fig. 8) (Title), comprising: a SiC substrate (10) ([0032]); and, a SiC epitaxial layer (composite layer of 21-23 and 29) laminated on the SiC substrate, wherein the SiC epitaxial layer comprises a first layer (21), an n-type second layer (composite layer of 22 and 29) directly on the first layer, because Applicants do not specifically claim whether the n-type second layer has a uniform doping concentration and/or a uniform material composition, and a third layer (23) directly on the second layer in order from a SiC substrate side, the SiC substrate has a nitrogen concentration of 5 × 1017 cm-3 or more and 1 × 1019 cm-3 or less ([0033]), the first layer has a nitrogen concentration of 5 × 1016 cm-3 or more and 1 × 1019 cm-3 or less ([0033]), the n-type second layer has a nitrogen concentration of between a nitrogen concentration of the second silicon carbide layer 22, which is 5 × 1018 cm-3 or more and 2 × 1019 cm-3 or less ([0033]), and a nitrogen concentration of the third silicon carbide layer 23, which is 1 × 1014 cm-3 or more and 5 × 1016 cm-3 or less ([0033]), inside the buffer layer 29 ([0051]), and the third layer has a nitrogen concentration of 1 × 1014 cm-3 or more and 5 × 1016 cm-3 or less or approximately 5 × 1015 cm-3 ([0033]), and wherein the nitrogen concentration of the n-type second layer (composite layer 22 and 29) is higher than the nitrogen concentration of the first layer (21), because (a) Applicants claim “a nitrogen concentration” of the first layer and “a nitrogen concentration” of the n-type second layer in claim 1, (b) therefore, a portion of the n-type second layer can have “a nitrogen concentration” lower than “a nitrogen concentration” of the first layer as long as another nitrogen concentration of the n-type second layer is higher than another nitrogen concentration of the first layer, and (c) in this case, one can arbitrarily select “a nitrogen concentration” of the first layer and “a nitrogen concentration” of the n-type second layer to meet the claim limitation, and the nitrogen concentration of the n-type second layer (composite layer of 22 and 29) is lower than the nitrogen concentration of the SiC substrate, because (a) Applicants claim “a nitrogen concentration” of the n-type second layer and “a nitrogen concentration” of the SiC substrate in claim 1, (b) therefore, a portion of the n-type second layer can have “a nitrogen concentration” higher than “a nitrogen concentration” of the SiC substrate as long as another nitrogen concentration of the n-type second layer is lower than another nitrogen concentration of the SiC substrate, and (c) in this case, one can arbitrarily select “a nitrogen concentration” of the n-type second layer and “a nitrogen concentration” of the SiC substrate to meet the claim limitation, while the another nitrogen concentration of the n-type second layer is higher than the another nitrogen concentration of the first layer.
Nakamura et al. differ from the claimed invention by not showing that the SiC substrate has a nitrogen concentration of 6.0 × 1018 cm-3 or more and 1.5 × 1019 cm-3 or less, the first layer has a nitrogen concentration of 1.0 × 1017 cm-3 or more and 1.5 × 1018 cm-3 or less, the n-type second layer has a nitrogen concentration of 1.0 × 1018 cm-3 or more and 3.7 × 1018 cm-3 or less, and the third layer has a nitrogen concentration of 5.0 × 1013 cm-3 or more and 1.0 × 1017 cm-3 or less, and the nitrogen concentration of the first layer is 0.3 times or less of the nitrogen concentration of the SiC substrate (claim 1), and the nitrogen concentration of the third layer is 1.0 × 1016 cm-3 or less (claim 11).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention that the SiC substrate can have a nitrogen concentration of 6.0 × 1018 cm-3 or more and 1.5 × 1019 cm-3 or less, the first layer can have a nitrogen concentration of 1.0 × 1017 cm-3 or more and 1.5 × 1018 cm-3 or less, the n-type second layer can have a nitrogen concentration of 1.0 × 1018 cm-3 or more and 3.7 × 1018 cm-3 or less, the third layer can have a nitrogen concentration of 5.0 × 1013 cm-3 or more and 1.0 × 1017 cm-3 or less, the nitrogen concentration of the first layer can be 0.3 times or less the nitrogen concentration of the SiC substrate, and the nitrogen concentration of the third layer can be 1.0 × 1016 cm-3 or less, because (a) as Applicants claim in the previously presented claim 8, the claimed nitrogen concentrations can each be measured at a single point, (b) each nitrogen concentration of the SiC substrate and first through third layer disclosed by Nakamura et al. overlap with each of the claimed ranges of the nitrogen concentration of the SiC substrate and first through third layer, (c) each of the nitrogen concentrations should be determined and optimized to achieve a desired electrical characteristic of the semiconductor device, (d) the nitrogen concentration of the first layer can be 0.3 times or less of the nitrogen concentration of the SiC substrate since, for example, when the nitrogen concentration of the SiC substrate is around 1 × 1019 cm-3, which is the upper limit of the range of the nitrogen concentration of the SiC substrate of 5 × 1017 cm-3 or more and 1 × 1019 cm-3 or less disclosed by Nakamura et al. and thus would have been obvious to one of ordinary skill in the art, the claimed nitrogen concentration of the first layer would be 0.3 × 1 × 1019 cm-3 or less, which is 0.3 × 1019 cm-3 or less, and this range of 0.3 × 1019 cm-3 or less overlaps with the nitrogen concentration of the first layer of 5 × 1017 cm-3 or more and 1 × 1019 cm-3 or less disclosed by Nakamura et al., and (e) the claims are prima facie obvious without showing that the claimed ranges of the nitrogen concentrations achieve unexpected results relative to the prior art range. In re Woodruff, 16 USPQ2d 1935, 1937 (Fed. Cir. 1990). See also In re Huang, 40 USPQ2d 1685, 1688 (Fed. Cir. 1996) (claimed ranges of a result effective variable, which do not overlap the prior art ranges, are unpatentable unless they produce a new and unexpected result which is different in kind and not merely in degree from the results of the prior art). See also In re Boesch, 205 USPQ 215 (CCPA) (discovery of optimum value of result effective variable in known process is ordinarily within skill of art) and In re Aller, 105 USPQ 233 (CCPA 1955) (selection of optimum ranges within prior art general conditions is obvious).
Regarding claim 2, Nakamura et al. differ from the claimed invention by not showing that a thickness of the n-type second layer is 2.0 µm or more.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention that the thickness of the n-type second layer 22 of Nakamura et al. can be 2.0 µm or more, because (a) the film thickness of the n-type second layer should be controlled and optimized to achieve a desired electrical characteristic of the second layer disclosed by Nakamura et al., and (b) the claim is prima facie obvious without showing that the claimed film thickness of the second layer achieves unexpected results relative to the prior art range. In re Woodruff, 16 USPQ2d 1935, 1937 (Fed. Cir. 1990). See also In re Huang, 40 USPQ2d 1685, 1688 (Fed. Cir. 1996) (claimed ranges of a result effective variable, which do not overlap the prior art ranges, are unpatentable unless they produce a new and unexpected result which is different in kind and not merely in degree from the results of the prior art). See also In re Boesch, 205 USPQ 215 (CCPA) (discovery of optimum value of result effective variable in known process is ordinarily within skill of art) and In re Aller, 105 USPQ 233 (CCPA 1955) (selection of optimum ranges within prior art general conditions is obvious).
Regarding claims 3 and 5, Nakamura et al. further disclose that a thickness of the first layer (21; 500 nm or 0.5 µm) is 0.2 µm or more and 2.0 µm or less ([0066]).
Regarding claim 7, Nakamura et al. disclose the SiC epitaxial wafer according to claim 1.
The claim limitation “the respective nitrogen concentrations … the 21 points are located greater than or equal to 5 mm from an edge of the SiC epitaxial wafer” specifies an intended use or a field of use, and is treated as non-limiting, because this limitation is directed to how to measure the claimed nitrogen doping concentrations as well as being indefinite as discussed above, since it has been held that in device claims, intended use must result in a structural difference between the claimed invention and the prior art in order to patentably distinguish the claimed invention from the prior art. If the prior art structure is capable of performing the intended use, then it meets the claim. In re Casey, 152 USPQ 235 (CCPA 1967); In re Otto, 136 USPQ 458, 459 (CCPA 1963). A claim containing a “recitation with respect to the manner in which a claimed apparatus is intended to be employed does not differentiate the claimed apparatus from a prior art apparatus” if the prior art apparatus teaches all the structural limitations of the claim. Ex Parte Masham, 2 USPQ 2d 1647 (Bd. Pat. App. & Inter. 1987).
Regarding claim 9, Nakamura et al. further disclose for the SiC epitaxial wafer according to claim 1 that the nitrogen concentration of the first layer (21) is higher than the nitrogen concentration of the third layer (23).
Response to Arguments
Applicants’ arguments with respect to claim 1 have been considered but are moot because the new ground of rejection does not rely on any reference applied in the prior rejection of record for any teaching or matter specifically challenged in the argument.
Conclusion
Applicants' amendment necessitated the new ground of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). Applicants are 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 JAY C KIM whose telephone number is (571) 270-1620. The examiner can normally be reached 8:00 AM - 6:00 PM EST.
Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice.
If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Joshua Benitez can be reached on (571) 270-1435. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
Information regarding the status of published or unpublished applications may be obtained from Patent Center. Unpublished application information in Patent Center is available to registered users. To file and manage patent submissions in Patent Center, visit: https://patentcenter.uspto.gov. Visit https://www.uspto.gov/patents/apply/patent-center for more information about Patent Center and https://www.uspto.gov/patents/docx for information about filing in DOCX format. For additional questions, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000.
/JAY C KIM/Primary Examiner, Art Unit 2815
/J. K./Primary Examiner, Art Unit 2815 July 28, 2026
Prosecution Insights