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 .
Election/Restrictions
Applicant's election with traverse of group I in the reply filed on 02/27/26 is acknowledged. The traversal is on the ground(s) that there is not a serious burden and the inventions are not independent and distinct. This is not found persuasive because there is a serious burden because the inventions require a different field of search (e.g., searching different classes/subclasses or electronic resources, or employing different search strategies or search queries). As to inventions not being independent and distinct, the law has long been established that dependent inventions (frequently termed related inventions) such as used for illustration above may be properly divided if they are, in fact, "distinct", even though dependent (see MPEP 802.01).
The requirement is still deemed proper and is therefore made FINAL.
Claim Rejections - 35 USC § 102
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 (i.e., changing from AIA to pre-AIA ) 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.
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.
Claim(s) 1, 3, 15, and 17-18 is/are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Hsieh, U.S. Patent 8,829,607.
Hsieh shows the invention as claimed including a power semiconductor device, comprising:
A semiconductor structure comprising a drift region 308 of a first conductivity type;
A plurality of gate trenches G respectively comprising sidewalls and a bottom surface therebetween extending in a first direction in the semiconductor structure; and
A plurality of support shielding structures 304 of a second conductivity type extending in the first direction in the semiconductor structure and spaced apart from the sidewalls of the gate trenches, wherein at least two of the gate trenches G are between immediately adjacent pairs of the support shielding structures 304 (see fig. 4A and col. 7-lines 47-58).
Concerning dependent claim 3, note that in Hsieh the at least two of the gate trenches are free of the support shielding structures therebetween, and are spaced apart by a first distance that is less than a second distance between pairs of the gate trenches having one or more of the support shielding structures therebetween (see fig. 4A and its description).
As to independent claim 15, note that Hsieh shows the invention as claimed including a power semiconductor device, comprising:
A semiconductor structure comprising a drift region of a first conductivity type;
A plurality of gate trenches G extending in a first direction in the semiconductor structure and spaced apart in a second direction; and
A plurality of support shielding structures 304 of a second conductivity type extending in the first direction in the semiconductor structure and spaced apart from respective sidewalls of the gate trenches in the second direction (see fig. 4A), wherein immediately adjacent pairs of the support shielding structures 304 having one or more of the gate trenches G therebetween are spaced apart at a first pitch, and immediately adjacent pairs of the gate trenches having one or more of the support shielding structures therebetween (note that the cell shown in fig. 4A is repeated in both a left and right direction) and are spaced apart at a second pitch that is different than the first pitch.
Concerning dependent claim 17, note that Hsieh discloses wherein at least two of the gate trenches are free of the support shielding structures therebetween and are spaced apart by a second distance that is less than the second pitch (see, for example, center part in fig. 4A).
Regarding dependent claim 18, note that Hsieh discloses a plurality of bottom shielding structures of the second conductivity type Pf extending in the semiconductor structure in the first direction under the gate trenches, respectively (see fig. 4A).
Claim(s) 1-2, 9, 11, 14-16, 18, 22, 25, and 28 is/are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Shindengen Electric Mfg. JP 2004-221218.
Shindengen Electric Mfg. shows the invention as claimed including a power semiconductor device, comprising:
A semiconductor structure comprising a drift region 12 of a first conductivity type;
A plurality of gate trenches 16a respectively comprising sidewalls and a bottom surface therebetween extending in a first direction in the semiconductor structure; and
A plurality of support shielding structures (16b,33b) of a second conductivity type extending in the first direction in the semiconductor structure and spaced apart from the sidewalls of the gate trenches, wherein at least two of the support shielding structures (16b,33b) are between immediately adjacent pairs of the support shielding structures 304 (see fig. 22A and description in machine translation).
With respect to dependent claim 2, note that Shindengen Electric Mfg also discloses wherein the at least two of the support shielding structures (16b,33b) are free of the gate trenches therebetween, and are spaced apart by a first distance that is less than a second distance between pairs of the support shielding structures having one or more of the gate trenches therebetween (see left part of fig. 22A, for example).
As to dependent claims 9 and 22, note that Shindengen Electric Mfg in fig. 22A discloses a metal contact providing a Schottky barrier with the semiconductor structure between a pair of the gate trenches.
Concerning dependent claims 10-11 and 27, note that Shindengen Electric Mfg discloses wherein the metal contact comprises a first metal layer (see, for example, fig. 22A and its description).
With respect to dependent claim 14, note that Shindengen Electric Mfg discloses in fig. 22A wherein the support shielding structures have a linear shape in plan view (see also fig. 31).
As to independent claim 15, note that Hsieh shows the invention as claimed including a power semiconductor device, comprising:
A semiconductor structure comprising a drift region 12 of a first conductivity type;
A plurality of gate trenches 16a extending in a first direction in the semiconductor structure and spaced apart in a second direction; and
A plurality of support shielding structures (16b,33b) of a second conductivity type extending in the first direction in the semiconductor structure and spaced apart from respective sidewalls of the gate trenches in the second direction, wherein immediately adjacent pairs of the support shielding structures having one or more of the gate trenches therebetween are spaced apart at a first pitch, and immediately adjacent pairs of the gate trenches 16a having one or more of the support shielding structures (16b,33b) therebetween are spaced apart at a second pitch (5d) that is different than the first pitch (see fig. 22A and its description and particularly its description in the machine translation).
With respect to dependent claim 16, note that Shindengen Electric Mfg in fig. 22A discloses wherein at least two of the support shielding structures (16b,33b) are free of the gate trenches therebetween and are spaced apart by a first distance, d, that is less than the first pitch 3d.
Concerning dependent claim 18, note that Shindengen Electric Mfg discloses a plurality of bottom shielding structures of the second conductivity type 33a extending in the semiconductor structure in the first direction under the gate trenches, respectively (see fig. 22A).
With respect to independent claim 25, note that Shindengen Electric Mfg discloses a power semiconductor device, comprising:
A semiconductor structure comprising a drift region 12 of a first conductivity type;
First and second gate trenches 16a extending in a first direction in the semiconductor structure;
First and second support shielding structures of a second conductivity type 16b,33b extending in the first direction in the semiconductor structure and spaced apart from sidewalls of the first and second gate trenches; and
A metal contact providing a Schottky barrier with the semiconductor structure between the first and second gate trenches (see fig. 22A and its description in machine translation).
Concerning dependent claim 28, note that Shindengen Electric Mfg discloses wherein the first and second support shielding structures are between the first and second gate trenches.
Claim(s) 25 and 29 is/are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Saito et al., U.S. Patent 7,755,138.
Saito et al. shows the invention as claimed including a power semiconductor device, comprising:
A semiconductor structure comprising a drift region 3 of a first conductivity type;
First and second gate trenches (8,9) extending in a first direction in the semiconductor structure (see fig. 11);
First and second support shielding structures 4 of a second conductivity type extending in the first direction in the semiconductor structure and spaced apart from sidewalls of the first and second gate trenches; and
A metal contact 10 providing a Schottky barrier with the semiconductor structure between the first and second gate trenches (see fig. 11 and col. 7-lines 54-67).
Concerning dependent claim 29, note that Saito et al. discloses wherein the first and second gate trenches (8,9) are between the first and second support shielding structures 3.
Claim Rejections - 35 USC § 103
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 (i.e., changing from AIA to pre-AIA ) 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.
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.
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
Claim(s) 10 and 26 is/are rejected under 35 U.S.C. 103 as being unpatentable over Shindengen Electric Mfg. JP 2004-221218.
Shindengen Electric Mfg. JP 2004-221218 is applied as above but does not expressly disclose a first metal layer providing ohmic contacts with the shielding structures and a second metal layer providing Schottky barrier with the semiconductor structure. However, official notice is taken that it would have been obvious to form the claimed ohmic/Schottky connections using this alternative arrangement because in such a way the respective contacts can be optimized in terms of their respective work functions and connections.
Claim(s) 4-8 and 19 is/are rejected under 35 U.S.C. 103 as being unpatentable over Hsieh, U.S. Patent 8,829,607 in view of Hung et al., US 2022/0223730.
Hsieh shows the invention as stated above but fails to expressly disclose the claimed bridge shielding structures. However, Hung et al. discloses a structure comprising shielding structures 70 located at the bottom of gate trenches and contacted by using a plurality of bridge shielding structures 50 of the second conductivity type extending in the semiconductor structure in a transversal direction, which crosses the first direction of the trenches, to contact the bottom shielding structures (see figs. 1-2 and paragraphs 0020-0023 and 0031). In view of this disclosure, it would have been obvious to one of ordinary skill in the art at the time the invention was filed to modify the primary reference of Hsieh so as to comprise the bridge shielding structures of Hung et al. because in such a way the on-state and gate-drain reverse capacitance can be improved.
With respect to claim 5, note that the support shielding structures of the bridge shielding structures in the device of Hsieh modified by Hung et al. discloses wherein at least one of the support or bridge shielding structures comprises a plurality of discrete segments with respective spacings therebetween along a direction of extension thereof in the first or second direction.
Concerning dependent claim 6, note that it would have been obvious to one of ordinary skill in the art at the time the invention was filed to form the support shield regions and bridge shield regions of the same width and/or depths that are substantially equal in order to simplify the overall manufacturing process.
As to dependent claim 8, note that Hsieh discloses that the support shielding structures 304 extend into the drift region 308 beyond the bottom shielding structures Pf.
Claim(s) 4-7, 19, 30, and 32 is/are rejected under 35 U.S.C. 103 as being unpatentable over Shindengen Electric Mfg. JP 2004-221218 in view of Hung et al., US 2022/0223730.
Shindengen Electric Mfg. JP 2004-221218 shows the invention as stated above and additionally discloses a plurality of bottom shielding structures 33a of the second conductivity type extending in the semiconductor structure in the first direction in the first direction under the gate trenches, respectively, where the bottom shielding structures 33a are connected to the base diffusion area 15a. However, JP ‘218 does not expressly disclose the claimed bridge shielding structures. However, Hung et al. discloses a structure comprising shielding structures 70 located at the bottom of gate trenches and contacted by using a plurality of bridge shielding structures 50 of the second conductivity type extending in the semiconductor structure in a transversal direction, which crosses the first direction of the trenches, to contact the bottom shielding structures (see figs. 1-2 and paragraphs 0020-0023 and 0031). In view of this disclosure, it would have been obvious to one of ordinary skill in the art at the time the invention was filed to modify the primary reference of Hsieh so as to comprise the bridge shielding structures of Hung et al. because in such a way the on-state and gate-drain reverse capacitance can be improved.
With respect to claim 5, note that the support shielding structures of the bridge shielding structures in the device of JP ‘218 modified by Hung et al. discloses wherein at least one of the support or bridge shielding structures comprises a plurality of discrete segments with respective spacings therebetween along a direction of extension thereof in the first or second direction.
Concerning dependent claims 6 and 32, note that it would have been obvious to one of ordinary skill in the art at the time the invention was filed to form the support shield regions and bridge shield regions of the same width and/or depths that are substantially equal in order to simplify the overall manufacturing process.
Regarding dependent claim 7, note that Hung et al. discloses that the width of the bridge shielding structure is in the range between 0.5 and 30 microns (see paragraph 0028) which overlaps with the claimed invention thereby establishing a prima facie case of obviousness. Therefore, it would have been obvious to one of ordinary skill in the art at the time the invention was filed to form the shielding structures in the claimed range as this is shown to be a suitable dimension to be formed in a power transistor configuration.
Claim(s) 12 is/are rejected under 35 U.S.C. 103 as being unpatentable over Shindengen Electric Mfg. JP 2004-221218 in view of Shindengen Electric Mfg. JP 2004-356383.
Shrindengen ‘218 is applied as above but does not expressly disclose wherein a material composition of the support shielding structures is different than that of the drift region. Shindengen Electric Mfg. JP 2004-356383 discloses that the filler material 34 of the support shielding structures is a second conductivity doped polycrystalline silicon (see fig. 7 and its description in machine translation). In view of this disclosure, it would have been obvious to one of ordinary skill in the art at the time the invention was filed to modify the primary reference of Shindengen Electric Mfg. JP 2004-221218 so as to comprise support shielding structures formed of polycrystalline silicon because this is shown by Shindengen Electric Mfg. JP 2004-356383 to be a suitable material for support shielding structures.
Claim(s) 13 is/are rejected under 35 U.S.C. 103 as being unpatentable over Shindengen Electric Mfg. JP 2004-221218 in view of Shindengen Electric Mfg. JP 2004-356383 as applied to claim 12 above, and further in view of Pein, U.S. Patent 5,378,912.
Shindengen Electric Mfg. JP 2004-221218 and Shindengen Electric Mfg. JP 2004-356383 are applied as above but do not expressly disclose wherein the drift region comprises a wide bandgap semiconductor material. However, Pein discloses a drift region of a power transistor formed of a wide bandgap semiconductor material (see abstract). In view of this disclosure, it would have been obvious to one of ordinary skill in the art at the time the invention was filed to modify the device of Shindengen Electric Mfg. JP 2004-221218 modified by Shindengen Electric Mfg. JP 2004-356383 so as to comprise a drift region of a wide bandgap material because Pien shows such a material to be suitable as a drift region.
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure. US Patent 7,465,986 discloses a power transistor comprising trench configurations.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to RICHARD A BOOTH whose telephone number is (571)272-1668. The examiner can normally be reached Monday to Friday, 8:30 to 5:00.
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/RICHARD A BOOTH/ Primary Examiner, Art Unit 2812
May 27, 2026
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