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 .
Response to Arguments
Applicant's arguments filed 11/5/2025 have been fully considered but they are not persuasive.
Applicant argues on page 7 that Blanchard in view of Saggio and Mizukami would not teach the claim language “a top-most surface of the conductive pillar is coplanar with the top-most surface of the epitaxial layer” as recited in claim 1 at least because element 120B of Blanchard extends into element 114, the asserted epitaxial layer.
Examiner respectfully disagrees. The instant application has 720 as the asserted epitaxial layer as shown in fig. 7 and explained at paragraph 51-55. To reconcile the recitation of the claim to the specification to make sense of the claim, there must exist, out of the plurality of layers of the epitaxial layer which make up 720, there exists one that has an upper surface which is coplanar with the upper surface of 730. Therefore, clearly, there exists an upper surface within 114 of Blanchard which would be coplanar with an upper surface of the conductive pillar 8 of Saggio. Applicant asserts further issues with Mizukami for the same issues with Blanchard. Examiner takes the position that the same reasonings above would apply in that instance.
Applicant further argues that Saggio’s conductive pillars 8 are an extension of the drain region as described in paragraph 66 and would fail to provide such function when combined with Blanchard. Examiner respectfully disagrees. This portion of the specification pertains to the embodiment of fig. 7, while the examiner is relying on the structure of fig. 8 and conductive pillars in fig. 8 are clearly used for forming a superjunction structure as is well-known in the art.
Arguments with respect to claims 6 and 14 are similar to those provided for claim 1, therefore the same reply above would apply.
Arguments are not found persuasive and the rejection has been updated to include the amended portions of the claims.
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.
Claim 9 is 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.
Claim 9 recites that “a top-most surface of the gate trench is above the epitaxial layer” at lines 1-3. It is unclear how a trench can have a top-most surface since a trench is formed by the lack of material, thus cannot have a surface.
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.
Claim(s) 1-20 is/are rejected under 35 U.S.C. 103 as being unpatentable over Blanchard et al. (US PGPub 2011/0193131; hereinafter “Blanchard”) in view of Saggio et al. (US PGPub 2013/0149838; hereinafter “Saggio”) and Mizukami et al. (US PGPub 205/0161732; hereinafter “Mizukami”).
Re claim 1: Blanchard teaches (e.g. fig. 1C) a super junction structure comprising: a substrate (110), wherein the substrate (110) has a first conductivity type (P+ type substrate 110; e.g. paragraph 35); an epitaxial layer (epitaxial drift region 114; e.g. paragraphs 35) over the substrate (110), wherein the epitaxial layer (114) has a second conductivity type (N--type layer epitaxial 114; e.g. paragraph 35) opposite the first conductivity type (P-type); a bury layer (N+ deep drain region 112; e.g. paragraph 35) between the epitaxial layer (114) and the substrate (110), wherein the bury layer (112) has the second conductivity type (N-type).
Blanchard is silent as to explicitly teaching a conductive pillar in the epitaxial layer, wherein the conductive pillar has the first conductivity type, sidewalls of the conductive pillar are angled with respect to a top-most surface of the epitaxial layer, a bottom surface of the conductive pillar is rounded, and a top-most surface of the conductive pillar is coplanar with the top-most surface of the epitaxial layer; and a gate trench, wherein the conductive pillar is below the gate trench.
Saggio teaches (e.g. fig. 8) a conductive pillar (p-type columnar structure 8; e.g. paragraphs 69 and 36) in the epitaxial layer (epi-layer 2; e.g. paragraph 69), wherein the conductive pillar (8) has the first conductivity type (P-type structures 8 within N-type drift layer 2), sidewalls of the conductive pillar (8) are angled (sidewalls of 8 are angled) with respect to a top-most surface of the epitaxial layer (2), a bottom surface (lower surface of 8) of the conductive pillar (8) is rounded, and a top-most surface (top surface of 8) of the conductive pillar (8) is coplanar with the top-most surface (top surface of 2) of the epitaxial layer (2).
Mizukami teaches (e.g. fig. 3) a gate trench (trench for trench gate 105), wherein the conductive pillar (109) is below the gate trench (trench for trench gate 105).
It would have been obvious to one of ordinary skill in the art, at the time of effective filling, absent unexpected results, to use the super junction structure as taught by Saggio and to use the location of super junction conductive pillars as taught by Mizukami in the device of Blanchard in order to have the predictable result of improving device performance, such as improving switching speed and reducing on-resistance and in order to have the predictable result of increasing current capacity by increasing the distance of the drift region, respectively.
Re claim 2: Blanchard in view of Saggio teaches the super junction structure of claim 1, wherein the conductive pillar (filling regions 6a made by epitaxial silicon; e.g. paragraph 44, 45 of Saggio) comprises a polymer material.
Re claim 3: Blanchard teaches the super junction structure of claim 1, wherein the first conductivity type comprises p-type (P+ type substrate 110 is of the first conductivity type; e.g. paragraph 35).
Re claim 4: Blanchard teaches the super junction structure of claim 1, wherein the gate trench (trench of trench gate 120B; e.g. paragraph 47) comprises an oxide layer and a polymer material.
Re claim 5: Blanchard in view of Saggio teaches the super junction structure of claim 1, further comprising a doped well (P-body well 12; e.g. paragraph 69 of Saggio), wherein the conductive pillar (8 of Saggio) is below the doped well (12 of Saggio).
Re claim 6: Blanchard teaches (e.g. fig. 1C) a super junction structure comprising :a substrate (110), wherein the substrate (110) has a first conductivity type (P+ type substrate 110; e.g. paragraph 35); an epitaxial layer (epitaxial drift region 114; e.g. paragraphs 35) over the substrate (110), wherein the epitaxial layer (114) has a second conductivity type (N--type layer epitaxial 114; e.g. paragraph 35) opposite the first conductivity type (P-type).
Blanchard is silent as to explicitly teaching a conductive pillar in the epitaxial layer, wherein the conductive pillar has the first conductivity type, sidewalls of the conductive pillar are angled with respect to a top-most surface of the epitaxial layer, and a bottom surface of the conductive pillar is rounded; a top-most surface of the conductive pillar is coplanar with the top-most surface of the epitaxial layer; and a gate trench over the conductive pillar.
Saggio teaches (e.g. fig. 8) a conductive pillar (p-type columnar structure 8; e.g. paragraphs 69 and 36) in the epitaxial layer (epi-layer 2; e.g. paragraph 69), wherein the conductive pillar (8) has the first conductivity type (P-type structures 8 within N-type drift layer 2), sidewalls of the conductive pillar (8) are angled (sidewalls of 8 are angled) with respect to a top-most surface of the epitaxial layer (2), and a bottom surface (lower surface of 8) of the conductive pillar (8) is rounded; and a top-most surface (top surface of 8) of the conductive pillar (8) is coplanar with the top-most surface (top surface of 2) of the epitaxial layer (2).
Mizukami teaches (e.g. fig. 3) a gate trench (trench for trench gate 105) over the conductive pillar (109).
It would have been obvious to one of ordinary skill in the art, at the time of effective filling, absent unexpected results, to use the super junction structure as taught by Saggio and to use the location of super junction conductive pillars as taught by Mizukami in the device of Blanchard in order to have the predictable result of improving device performance, such as improving switching speed and reducing on-resistance and in order to have the predictable result of increasing current capacity by increasing the distance of the drift region, respectively.
Re claim 7: Blanchard teaches the super junction structure of claim 6, further comprising a bury layer (N+ deep drain region 112; e.g. paragraph 35) between the epitaxial layer (114) and the substrate (110).
Re claim 8: Blanchard teaches the super junction structure of claim 7, wherein the bury layer (N+ deep drain region 112; e.g. paragraph 35) has the second conductivity type (N-type).
Re claim 9: Blanchard in view of Saggio and Mizukami teaches the super junction structure of claim 6, wherein a top-most surface (top surface of 20 of Saggio) of the gate trench (trench for 105 of Mizukami) is above the epitaxial layer (100 of Mizukami).
Re claim 10: Blanchard in view of Saggio and Mizukami teaches the super junction structure of claim 6, wherein the gate trench (trench of trench gate 105 of Mizukami) lands on the conductive pillar (109 of Mizukami).
Re claim 11: Blanchard in view of Saggio teaches the super junction structure of claim 6, further comprising a doped well (P-body well 12; e.g. paragraph 69 of Saggio) over the conductive pillar (8 of Saggio).
Re claim 12: Blanchard in view of Saggio teaches the super junction structure of claim 6, further comprising a second conductive pillar (another one of the conductive pillar 8) in the epitaxial layer (114 of Blanchard/2 of Saggio).
Re claim 13: Blanchard teaches the super junction structure of claim 12, wherein a portion of the epitaxial layer (2 of Saggio) is between the conductive pillar (8 of Saggio) and the second conductive pillar (an adjacent one of 8 of Saggio).
Re claim 14: Blanchard teaches (e.g. fig. 1C) a super junction structure comprising: a substrate (110), wherein the substrate (110) has a first conductivity type (P+ type substrate 110; e.g. paragraph 35); an epitaxial layer (epitaxial drift region 114; e.g. paragraphs 35) over the substrate (110), wherein the epitaxial layer (114) has a second conductivity type (N--type layer epitaxial 114; e.g. paragraph 35) opposite the first conductivity type (P-type).
Blanchard is silent as to explicitly teaching a plurality of conductive pillars in the epitaxial layer, wherein each of the plurality of conductive pillars has the first conductivity type, a distance between adjacent conductive pillars of the plurality of conductive pillars increases as a distance from a top surface of the epitaxial layer increases, a top-most surface of the conductive pillar is coplanar with the top-most surface of the epitaxial layer, and a bottom surface of a first conductive pillar of the plurality of conductive pillars is rounded; and a gate trench above the conductive pillar.
Saggio teaches (e.g. fig. 8) a plurality of conductive pillar (p-type columnar structure 8; e.g. paragraphs 69 and 36) in the epitaxial layer (epi-layer 2; e.g. paragraph 69), wherein each of the plurality of conductive pillars (8) has the first conductivity type (P-type structures 8 within N-type drift layer 2), a distance between adjacent conductive pillars (8) of the plurality of conductive pillars (8) increases as a distance from a top surface of the epitaxial layer (2) increases, and a top-most surface (top surface of 8) of the conductive pillar (8) is coplanar with the top-most surface (top surface of 2) of the epitaxial layer (2), and a bottom surface of a first conductive pillar (8) of the plurality of conductive pillars is rounded.
Mizukami teaches (e.g. fig. 3) a gate trench (trench for trench gate 105) over the conductive pillar (109).
It would have been obvious to one of ordinary skill in the art, at the time of effective filling, absent unexpected results, to use the super junction structure as taught by Saggio and to use the location of super junction conductive pillars as taught by Mizukami in the device of Blanchard in order to have the predictable result of improving device performance, such as improving switching speed and reducing on-resistance and in order to have the predictable result of increasing current capacity by increasing the distance of the drift region, respectively.
Re claim 15: Blanchard in view of Saggio teaches the super junction structure of claim 14, wherein sidewalls of the first conductive pillar (8 of Saggio) are angled with respect to the top surface of the epitaxial layer (2 of Saggio).
Re claim 16: Blanchard teaches the super junction structure of claim 15, wherein sidewalls of a second conductive pillar (8 of Saggio) of the plurality of conductive pillars (8 of Saggio) are angled with respect to the top surface of the epitaxial layer (2 of Saggio).
Re claim 17: Blanchard teaches the super junction structure of claim 14, further comprising a buried layer (12) between the substrate (110) and the epitaxial layer (114).
Re claim 18: Blanchard in view of Saggio teaches the super junction structure of claim 14, further comprising a doped well (P-body well 12; e.g. paragraph 69 of Saggio) above the first conductive pillar (8 of Saggio).
Re claim 19: Blanchard in view of Saggio teaches the super junction structure of claim 14, wherein a portion of the epitaxial layer (2 of Saggio) is between the adjacent conductive pillars (8 of Saggio).
Re claim 20: Blanchard in view of Saggio teaches the super junction structure of claim 14, wherein the buried layer (112) is below each of the plurality of conductive pillars (8 of Saggio).
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure. US 6,979,862 to Henson shows at fig. 4 that the location of the p-regions of the superjuction can be moved from between trench gates to under trench gates.
THIS ACTION IS MADE FINAL. 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 JESSE Y MIYOSHI whose telephone number is (571)270-1629. The examiner can normally be reached M-F, 8:30AM-5:00PM.
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/JESSE Y MIYOSHI/
Primary Examiner, Art Unit 2898
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