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 .
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 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.
Response to Amendment
Applicant's amendment to the claims, filed on May 21st, 2026, is acknowledged. Entry of amendment is accepted and made of record.
Response to Arguments/Remarks
Applicant's response filed on May 21st, 2026 is acknowledged and isanswered as follows.
Applicant's arguments, see pgs. 7-10, with respect to the rejections of claims under 35 U.S.C 102 (a)(1) and/or 35 U.S.C 103(a) have been considered but are moot in view of the new ground(s) of rejection.
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.
Claims 1-6 and 12 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 pre-AIA the applicant regards as the invention.
Claim 1 recites limitation “the substrate disposed on the guard ring” in lines 11-12 while claim 1 also recites limitation “a substrate comprising a device region and a guard ring region” in line 3. It is unclear to the examiner if the guard ring is part of the substrate or the substrate is disposed on top of the guard ring.
Claim 3 recites a redundant “the guard ring region is doped with a second dopant ion having conductivity type different from the conductivity type of the first dopant ion” in lines 1-3 because claim 1 already recites the same limitation in lines 9-10.
Claim 4 recites “a top surface of the guard ring is flush with a top surface of the substrate” which conflicts with the limitation of claim 1 in lines 10-11 reciting “the substrate disposed on the guard ring”. It is unclear to the examiner if the top surface of guard ring is flush with the top surface of the substrate or lower than the top surface of the substrate.
Claim 2-9 and 12 are rejected for being depended on claim 1 and having the above issues incorporated into the claims.
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.
(a)(2) the claimed invention was described in a patent issued under section 151, or in an application for patent published or deemed published under section 122(b), in which the patent or application, as the case may be, names another inventor and was effectively filed before the effective filing date of the claimed invention.
Claims 1-4, 6 and 12 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by NOBORIO et al. (Pub. No.: US 2020/0227549 A1), hereinafter as NOBORIO.
Regarding claim 1, NOBORIO discloses a method for forming a semiconductor structure in Figs. 4A-4I, comprising: providing a substrate (combination of substrate 1 and layer 2) comprising a device region (cell region RC) and a guard ring region (guard ring region RG) surrounding the device region (see Fig. 4A and [0047], [0076-0077]); and forming a power device (forming MOSFET in cell region RC) in the device region and forming a guard ring (guard ring 21) in the guard ring region, wherein the guard ring is doped with a first dopant ion (p-type ions) that is formed by a partial doping process (ion implantation) used in forming the power device, and a conductivity type of the first dopant ion in the guard ring (p-type conductivity of guard ring 21) is different from a device type of the power device (n-type channel device of the MOSFET in cell region RC) (see Fig. 4B-4I and [0079], [0084-0090]); wherein the guard ring region is doped with a second dopant ion (n-type dopant ion) having a conductivity type different from the conductivity type of the first dopant ion (guard ring region RG of layer 2 is made of SiC and must doped with n-type dopant to be n-type during epi growth) (see Fig. 4A and [0077]), so that the substrate disposed on the guard ring forms a completely depleted layer with the guard ring (a completely depleted layer would form at p-n junction between guard ring 21 and guard ring region RG of layer 2).
Regarding claim 2, NOBORIO discloses the method according to claim 1, wherein the partial doping process comprises an ion implantation doping process (see Fig. 4B and [0079]).
Regarding claim 3, NOBORIO discloses the method according to claim 1, wherein the guard ring region is doped with a second dopant ion (n-type dopant ion) having a conductivity type different from the conductivity type of the first dopant ion (guard ring region RG of layer 2 is made of SiC and must doped with n-type dopant to be n-type during epi growth) (see Fig. 4A and [0077]), and a top surface of the guard ring is lower than a top surface of the substrate (top surface of guard ring 21 is lower than top surface of layer 2) (see Fig. 4B).
Regarding claim 4, NOBORIO discloses the method according to claim 1, wherein a top surface of the guard ring is flush with a top surface of the substrate (since claim 4 being rejected under 112, the assumption is made that the top surface of the guard ring is lower than the top surface of the substrate) (top surface of guard ring 21 is lower than top surface of layer 2) (see Fig. 4B).
Regarding claim 6, NOBORIO discloses the method according to claim 1, wherein when the power device is an N-type power device (n-type channel device of the MOSFET in cell region RC being determined by n+ source 4, p-type base region 3, n-type drift 2 and n+ drain 1) (see Fig. 4I and [0084-0087]), the first dopant ion in the guard ring is P-type ion (see Fig. 4I and [0084]).
Regarding claim 12, NOBORIO discloses the method according to claim 1, further comprising: defining an ion implantation position in the guard ring region by relying on a mask (mask 40) used to form the power device (using mask 40 to form both guard ring 21 and lower portions 5a of MOSFET) (see Figs. 4B-4I and [0079-0082]).
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 of this title, 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.
The factual inquiries set forth in Graham v. John Deere Co., 383 U.S. 1, 148 USPQ 459 (1966), that are applied for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
a. Determining the scope and contents of the prior art.
b. Ascertaining the differences between the prior art and the claims at issue.
c. Resolving the level of ordinary skill in the pertinent art.
d. Considering objective evidence present in the application indicating obviousness or nonobviousness.
Claim 5 is rejected under 35 U.S.C. 103 as being unpatentable over NOBORIO et al. (Pub. No.: US 2020/0227549 A1), hereinafter as NOBORIO, as applied to claim 1 and further in view of MIMURA et al. (Pub. No.: US 2024/0290616 A1), hereinafter as Mimura.
Regarding claim 5, NOBORIO discloses the method according to claim 1, but fails to disclose wherein when the power device is a P-type power device, the first dopant ion in the guard ring is N-type ion.
Mimura discloses a method of forming a semiconductor device in Fig. 1 wherein a power device (trench gate MOSFET) can be either N-type power device or P-type power device (see [0075]) and the first dopant ion in the guard ring either be P-type ion or N-type ion (see [0075]).
Modifying the method of NOBORIO for forming N-type power device having all one conductivity type convert to the opposite conductivity type as same as the method of Mimura for disclosing a P-type power device and the first dopant ion in the guard ring is N-type ion as recited in claim 5.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to modify the N-type power device and P-type ion of the first dopant of NOBORIO to P-type power device and N-type ion of the first dopant because it is conventional to form both N-type and/or P-type power device by switching the conductivity of layers for forming complementary of integrated circuit.
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 extension fee 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 date of this final action.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to CUONG B NGUYEN whose telephone number is (571)270-1509 (Email: CuongB.Nguyen@uspto.gov). The examiner can normally be reached Monday-Friday, 8:30 AM-5:00 PM Eastern Standard Time.
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If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Steven H. Loke can be reached on (571) 272-1657. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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/CUONG B NGUYEN/Primary Examiner, Art Unit 2818
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