DETAILED ACTION
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Status of the Claims
Group I was elected.
Amendment filed May 04, 2026 is acknowledged. New Claims 17-21 have been added. Claims 1 and 8-9 have been amended. Non-elected Invention, Group II, Claims 10-15 have been withdrawn from consideration. Claims 1-15 and 17-21 are pending.
Action on merits of Elected Invention, Group I, claims 1-9 and 17-21 follows.
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.
Claim 20 is rejected under 35 U.S.C. 112(a) 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.
There does not appear to be a written description of the claim limitation “A power semiconductor device according to claim 1, wherein the gate electrode has a section which tapers towards the top side.” (new claim 20) (emphasis added) in the application as filed.
According to the specification, the limitation “the gate electrode has a section which tapers towards the top side” directed to embodiment as shown in FIG. 2.
However, according to independent claim 1, lines 21-22 recites: “- in plan view of the top side, an entirety of the gate electrode is disposed outside of the drift region”.
The above limitation direct the claim invention to embodiment of FIG. 1, the gate electrodes 3 is disposed outside of the drift region 14, but do not have “tapers” sections.
Thus, claim 20 contains new matter.
Moreover, amended claim 1 recites: “wherein the drift region is epitaxially grown in a hole etched into a base semiconductor body and projects beyond the base region at the top side, and wherein the gate electrode is formed before an epitaxial growth of the drift region”
As shown in FIG. 2 where claim 20 recites: “the gate electrode has a section which tapers towards the top side”, the gate electrode 3 is formed after, not before, the drift region 14 and the contact region 13.
Thus, claim 20, further, contains new matter.
Applicant must cancel the un-support new matters in response to the Office Action.
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 1-9 and 17-21 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.
A single claim which claims both an apparatus, the instant “power semiconductor device”, and the method steps of forming the apparatus, the instant “wherein the drift region is epitaxially grown in a hole etched into a base semiconductor body and projects beyond the base region at the top side, and wherein the gate electrode is formed before an epitaxial growth of the drift region”, is indefinite under 35 U.S.C. 112, second paragraph. In Ex parte Lyell, 17 USPQ2d 1548 (BPAI 1990).
The limitations, structure and method steps, in a single claim, creates confusion as to when direct infringement occurs.
Therefore, claim 1 and all dependent claims are indefinite.
Regarding claim 21, in addition to the limitations, indefiniteness, of independent claim 1, as discussed above, claim 21 also recites: “wherein the contact region is epitaxially grown in a hole etched into a base semiconductor body and projects beyond the base region at the top side”.
Thus, claim 21 additionally claimed another “method step”: “the contact region is epitaxially grown in a hole etched into a base semiconductor body …”.
Therefore, claim 21 is further indefinite.
Claim 18 recites the limitation "a power semiconductor device according to claim 1, wherein the contact region adjoins the electrically isolating material covering lateral surfaces of the gate electrode". There is insufficient antecedent basis for this limitation in the claim.
According to claim 1, lines 5-6, recites: “the gate electrode is electrically isolated from the semiconductor body by an electrically isolating material,”
Which means the “electrically isolating material” (5) is formed under the gate electrode, as shown in FIG. 7.
The limitation of new claim 18, “the electrically isolating material covering lateral surfaces of the gate electrode” is not the same as the “electrically isolating material” (5) that is electrically isolated the gate electrode from the semiconductor body 1’.
Thus, the limitation “the electrically isolating material covering lateral surfaces of the gate electrode” lacks antecedent support.
Therefore, claim 18 is indefinite.
Similarly, claim 19 recites: a power semiconductor device according to claim 1, wherein the drift region adjoins the electrically isolating material covering lateral surfaces of the gate electrode.
Thus, claim 19 lacks antecedent support. Therefore, claim 19 is indefinite.
Regarding claim 20, amended claim 1 recites: “wherein the drift region is epitaxially grown in a hole etched into a base semiconductor body and projects beyond the base region at the top side, and wherein the gate electrode is formed before an epitaxial growth of the drift region”
As shown in FIG. 2 where claim 20 recites: “the gate electrode has a section which tapers towards the top side”, the gate electrode 3 is formed after, not before, the drift region 14 and the contact region 13. (See page 20, lines 11-13).
Thus, claim 20, further, contains new matter.
Regarding claim 21, new claim 21 recites: “wherein the contact region is epitaxially grown in a hole etched into a base semiconductor body and projects beyond the base region at the top side”.
However, amended claim 1 recites:
“the semiconductor body comprises: …
- a contact region of the first conductivity type arranged vertically between the drift layer and the top side, wherein the contact region adjoins the base region and the top side,”
According to new claim 21, the “contact region” is formed in two different “semiconductor body”, namely, “semiconductor body” of claim 1 and “a base semiconductor body”.
The limitation of claim 21 contravenes the limitations of independent claim 1.
Therefore, claim 21 is indefinite.
The examination on merits of all claims are determined solely on the structure.
Claim Objections
Applicant is advised that should claim 17 be found allowable, claim 21 will be objected to under 37 CFR 1.75 as being a substantial duplicate thereof. When two claims in an application are duplicates or else are so close in content that they both cover the same thing, despite a slight difference in wording, it is proper after allowing one claim to object to the other as being a substantial duplicate of the allowed claim. See MPEP § 608.01(m).
New claim 17 recites: A power semiconductor device according to claim 1, wherein, at the top side, the contact region also projects beyond the base region in vertical direction.
New claim 21 recites: A power semiconductor device according to claim 1, wherein the contact region is epitaxially grown in a hole etched into a base semiconductor body and projects beyond the base region at the top side”.
As a structure, claim 17 and claim 21 cover the same thing “the contact region projects beyond the base region in vertical direction or at the top side”.
Claim Rejections - 35 USC § 102
The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action.
Claims 1-7 and 18-20 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by HSHIEH et al. (US. Patent No. 5,907,169) of record.
With respect to claim 1, As best understood by the Examiner, HSHIEH ‘169 teaches a power semiconductor device as claimed including:
- a semiconductor body with a top side,
- a main electrode (source electrode) on the top side and
- a gate electrode (230) on the top side and arranged next to the main electrode in a first lateral direction, the gate electrode (230) is electrically isolated from the semiconductor body by an electrically isolating material (132), wherein
- the semiconductor body comprises
- a drift layer (210) of a first conductivity type (N),
- a base region (240) of a second conductivity type (P) arranged vertically between the drift layer (210) and the top side,
- a contact region (225’) of the first conductivity type arranged vertically between the drift layer (210) and the top side, wherein the contact region (225’) adjoins the base region (240) and the top side,
- a drift region (212) of the first conductivity type (N) arranged next to the base region (240) in the first lateral direction and adjoining the base region (240),
- the main electrode is in electrical contact with the contact region (225’),
- in plan view of the top side, the gate electrode (230) at least partially covers a channel portion of the base region (240) which lies, in the first lateral direction, between the contact region (225’) and the drift region (212),
- at the top side, the drift region (212) projects beyond the base region (240) in vertical direction,
- in plan view of the top side, an entirety of the gate electrode (230) is disposed outside of the drift region (212), and
wherein the drift region (212) is epitaxially grown in a hole etched into a base semiconductor body and projects beyond the base region at the top side, and wherein the gate electrode is formed before an epitaxial growth of the drift region. (See FIGs. 5A, 7).
Product by process limitation:
The expression “wherein the drift region is epitaxially grown in a hole etched into a base semiconductor body and projects beyond the base region at the top side, and wherein the gate electrode is formed before an epitaxial growth of the drift region” is/are taken to be a product by process limitation and is given no patentable weight. A product by process claim directed to the product per se, no matter how actually made, In re Hirao, 190 USPQ 15 at 17 (footnote 3). See In re Fessman, 180 USPQ 324, 326 (CCPA 1974); In re Marosi et al., 218 USPQ 289, 292 (Fed. Cir. 1983); In re Brown, 459 F.2d 531, 535, 173 USPQ 685, 688 (CCPA 1972); In re Pilkington, 411 F.2d 1345, 1348, 162 USPQ 145, 147 (CCPA 1969); Buono v. Yankee Maid Dress Corp., 77 F.2d 274, 279, 26 USPQ 57, 61 (2d. Cir. 1935); and particularly In re Thorpe, 227 USPQ 964, 966 (Fed. Cir. 1985), all of which make it clear that it is the patentability of the final structure of the product “gleaned” from the process steps, which must be determined in a “product by process” claim, and not the patentability of the process. See also MPEP 2113. Moreover, an old and obvious product produced by a new method is not a patentable product, whether claimed in “product by process” claims or not.
Note that Applicant has burden of proof in such cases as the above case law makes clear.
The power semiconductor device of HSHIEH
Regarding the term “wherein the drift region is epitaxially grown in a hole etched into a base semiconductor body and projects beyond the base region at the top side, and wherein the gate electrode is formed before an epitaxial growth of the drift region”
Since the drift region 212 of HSHIEH is epitaxially grown and projects beyond the base region, to reduce parasitic gate/drain capacitance is inherently resulted.
With respect to claim 2, at least one of the contact region (225’) and the drift region (212) of HSHIEH is grown epitaxially.
With respect to claim 3, at least one of the epitaxially grown regions of HSHIEH has
- an inverted doping profile with a doping concentration decreasing in a direction pointing from an interior of the semiconductor body towards the top side or
- a homogenous doping profile.
With respect to claim 4, the contact region (225’) and the channel portion of HSHIEH at least partially overlap with each other when viewed along the first lateral direction.
With respect to claim 5, the drift region (212) of HSHIEH has a greater doping concentration than the drift layer (210).
With respect to claim 6, in plan view of the top side, the gate electrode (230) of HSHIEH partially covers the contact region (225’).
With respect to claim 7, the power semiconductor device of HSHIEH is a MOSFET or an IGBT or a MISFET.
With respect to claim 18, As best understood by the Examiner, the contact region (125’) of HSHIEH adjoins the electrically isolating material (120/132/150) covering lateral surfaces of the gate electrode (130).
With respect to claim 19, As best understood by the Examiner, the drift region (115’) of HSHIEH adjoins the electrically isolating material (132) covering lateral surfaces of the gate electrode (130).
With respect to claim 20, As best understood by the Examiner, the gate electrode (130) of HSHIEH has a section which tapers towards the top side.
Claim Rejections - 35 USC § 103
The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action.
Claim 8 is rejected under 35 U.S.C. 103 as being unpatentable over HSHIEH ‘169 as applied to claim 1 above, and further in view of HUANG (CN pub. No. 109244119) of record.
HSHIEH teaches the power semiconductor device as described in claim 1 above including the semiconductor body is based on Si, and the drift region (115) projects beyond the base region (140) by at least 50 nm to reduce parasitic gate/drain capacitance.
Thus, HSHIEH is shown to teach all the features of the claim with the exception of explicitly disclosing the semiconductor body being based on SiC.
However, HUANG teaches a power semiconductor device utilizing a semiconductor body based on SiC having a bandgap wider than silicon.
Therefore, it would have been obvious to one having ordinary skill in the art at the time of invention was made to form the power semiconductor device of HSHIEH utilizing the wide-bandgap semiconductor as taught by HUANG to provide for a MOS device having higher avalanche resistance.
Moreover, given a finite number of materials and their compounds, it is obvious to try without undue experimentation.
Further, it has been held to be within the general skill of a worker in the art to select a known material on the basis of it suitability for the intended use as a matter of obvious design choice. In re Leshin, 125 USPQ 416., 125 USPQ 416.
Claim 9 is rejected under 35 U.S.C. 103 as being unpatentable over HSHIEH ‘169 as applied to claim 1 above, and further in view of KOJIMA et al. (US. Pub. No. 2005/0230686).
HSHIEH teaches the power semiconductor device as described in claim 1 above including the gate electrode (230) projecting beyond the base region (240) at least partially overlap with each other when viewed along the first lateral direction.
Thus, HSHIEH is shown to teach all the features of the claim with the exception of explicitly disclosing the contact region projecting beyond the base region.
However, KOJIMA teaches a power semiconductor device including gate electrode (8) and the contact region (4b) projecting beyond the base region (3b) at least partially overlap with each other when viewed along the first lateral direction. (See FIG. 1).
Therefore, it would have been obvious to one having ordinary skill in the art at the time of invention was made to form the semiconductor device of HSHIEH having the gate electrode and the contact region projecting beyond the base region as taught by KOJIMA to improve channel mobility.
Claims 17 and 21 are rejected under 35 U.S.C. 103 as being unpatentable over HSHIEH ‘169 as applied to claim 1 above, and further in view of HARRIS et al. (US. Pub. No. 2008/0203398).
With respect to claim 17, As best understood by the Examiner, HSHIEH teaches the power semiconductor device as described in claim 1 above including at the top side, the contact region (125’) also projects beyond the drift layer (110).
Thus, HSHIEH is shown to teach all the features of the claim with the exception of explicitly disclosing the contact region also projects beyond the base region.
However, HARRIS teaches a power semiconductor device including:
- a semiconductor body comprises
- a drift layer (10) of a first conductivity type,
- a base region (22) of a second conductivity type arranged vertically between the drift layer (10) and a top side (12),
- a contact region (36) of the first conductivity type arranged vertically between the drift layer (10) and the top side (12), wherein the contact region (36) adjoins the base region (22) and the top side,
wherein, at the top side (12), the contact region (36) projects beyond the base region (22) in vertical direction. (See FIG. 10).
Therefore, it would have been obvious to one having ordinary skill in the art at the time of invention was made to form the contact region of HSHIEH projects beyond the base region in vertical direction as taught by HARRIS to realized higher electron mobility.
With respect to claim 21, As best understood by the Examiner, in view of HARRIS, the contact region (36) is epitaxially grown in a hole etched into a base semiconductor body (10) and projects beyond the base region (22) at the top side.
Response to Arguments
Applicant's arguments filed January 08, 2026 have been fully considered but they are not persuasive.
Rejection Under 35 USC § 102
Applicant argues:
In contrast, claim 1 as amended requires that "the drift region is epitaxially grown in a hole etched into a base semiconductor body." This is an additive process where a hole is first etched and then the drift region is grown epitaxially within that hole. HSIEH does not disclose or teach this structural and process limitation.
Applicant clearly affirmed that amended claim 1 intentionally contained both structural and method steps.
First of all, the claimed invention is a structure claim, not a method claim. Therefore, the “method” limitation(s) of the claim(s), i.e., hole etched into a base semiconductor body (sic), is determined to be a product-by-process, another words, the “process” limitation(s) is/are given no patentable weight. (See the citations in the rejection above).
Secondly, the drift region 115’ of HSHIEH is clearly epitaxial grown since layer 115 is a doped portion of the epitaxially grown drift layer 110, hence “epitaxially grown” is met.
Thirdly, Applicant asserts: “HSHIEH does not epitaxially grow the drift region at all - the raised terrace is part of the pre-existing epitaxial layer”.
Applicant clearly acknowledged that the drift region of HSHIEH is epitaxially grown.
Structurally, the drift region 115’ is being formed in a region lower than and between raised gate electrodes 130 and above the base region 140, hence in the “hole”.
Therefore, structurally, the limitations of amended claim 1 are met.
Rejection Under 35 USC § 103
With respect to claim 8, Applicant asserts: “Claim 8 depends from claim 1 and therefore incorporates all limitations of claims as amended.”
Since all limitations of amended claim 1 is being anticipated by HSHIEH, claim 8 is obvious over HSHIEH and KOJIMA as shown in the rejection.
The rejection of claim 8, thus, maintained.
The same also applied to claim 9.
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.
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/ANH D MAI/ Primary Examiner, Art Unit 2893
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