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 .
Information Disclosure Statement
The information disclosure statement (IDS) submitted on 09/20/2022, 05/08/2023, 04/24/2024, 08/08/2024,03/14/2025 and 08/05/20258 were filed after the mailing date of the non-final action. The submission is in compliance with the provisions of 37 CFR 1.97. Accordingly, the information disclosure statement is being considered by the examiner.
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.
(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 and 6 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Goller (US 2020/0365385 A1).
Re claim 1: Goller teaches (fig.1-6B) A method for manufacturing a vertical conduction silicon carbide electronic device, the method comprising:
forming a rough face (106/120 contains surface with high roughness par.58) from a first face (110) of a silicon carbide substrate (114), the rough face (106/120) having a roughness higher (par.60) than a threshold (zero threshold);
depositing (fig. 6A), on the rough face (106/120), a metal layer (602);
and forming (fig. 6B) a silicide layer (604) by annealing (par.90) the metal layer (602), the silicide layer (604) having a plurality of protrusions (metal layer 602 and porous layer 120 are thermally treated and so would result in protrusions of silicide) of silicide (nickel silicide, par.90)
Re claim 2: The method according to claim 1, wherein the threshold is a root mean square value of a roughness of the rough face, the root mean square value being equal to or higher (par.57, 106/110 can be 1-100 µm which is much greater than 30 nm) than 30 nm.
Re claim 3: Goller teaches the method according to claim 1, wherein the forming the rough face (106/120) comprises thinning (par.65) the silicon carbide substrate (114) from the first face (110), thereby forming a thinned layer (106/120 after grinding hereinafter TL) having the rough face (106/120).
Re claim 4: Goller teaches the method according to claim 3, wherein the forming the rough face (106/120) includes grinding (par.65) the thinned layer (TL) of the silicon carbide substrate (114), on the first face (110), with an abrasive surface (Par. 39 mentions using a coarse grinding wheel).
Re claim 6: Goller teaches the method according to claim 3, wherein the thinned layer (TL) has a thickness (par.57) between about 100 µm and about 250 µm.
Claims 12 and 15-20 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Joshi (US 2018/0174840 A1).
Re claim 12: Joshi teaches (figs.5B and 9) A vertical conduction silicon carbide electronic device, comprising:
a body of silicon carbide (100); and a contact region (region with 300 , hereinafter CR) of silicide (305) on the body (100), the contact region (CR) including a connection surface (139), wherein the contact region (region with 300 , hereinafter CR) includes a plurality of first protrusions (bigger-sized 300) of silicide (silicide kernels) on the connection surface (139), the plurality of first protrusions (bigger-sized 300) having a density that is higher than a threshold (zero threshold).
Re claim 15: Joshi teaches the device according to claim 12, comprising a metallization layer (302) on the contact region (CR).
Re claim 16: Joshi teaches the device according to claim 12, wherein the body (100) includes a plurality of second protrusions (smaller-sized 300) on a surface of the body (100) that interfaces with the contact region (CR).
Re claim 17: Joshi teaches the device according to claim 12, further comprising a drift layer (131) on a side (as shown in fig. 9) of the body opposite to the contact region (CR).
Re claim 18: Joshi teaches device according to claim 17, further comprising a connection structure (139) on the drift layer (131).
Re claim 19: Joshi teaches (figs. 5B and 9) a structure, comprising:
a silicon carbide body (100), the silicon carbide body (100) including a first surface (101) and a second surface (102) opposite to the first surface (101), the second surface (102) including a plurality of first protrusions (bigger sized 300);
a silicide layer (305) on the second surface (102);
and a drift layer (131) on the first surface (101).
Re claim 20: The structure of claim 19, wherein the silicide layer (305) including a plurality of second protrusions (smaller sized 300) on a surface of the silicide layer (305) that is distal to the silicon carbide body (100).
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) 7-10 are rejected under 35 U.S.C. 103 as being unpatentable over Goller (US 2020/0365385 A1) as applied to claim 1, and in further view of Hostetler (US 8,962,468 B1).
Re claim 7: Goller teaches the the method according to claim 1,
Goller is silent to teach wherein the metal layer has a contact face and the annealing the metal layer includes laser annealing the contact face of the metal layer with a laser beam.
Hostetler teaches (fig.3A-3C) wherein the metal layer (300) has a contact face (top surface of 300) and the annealing the metal layer (300) includes laser annealing (col.7 lines 1-17) the contact face (top surface of 300) of the metal layer (300) with a laser beam (201).
It would have been obvious to use the laser annealing technique as taught in Hostetler to anneal the metal layer in Goller in order to have the predictable result of localized and precise heating that is commonly known in the art to reduce defects and prevent crystal damage to ultimately improve electrical performance in semiconductor devices.
Re claim 8: Goller in view of Hostetler teach the method according to claim 7, wherein the laser beam (201 of Hostetler would be used in the device of Goller) has a footprint (d3 of Hostetler) smaller than the contact face (top surface of 300 of Hostetler/602 of Goller) and the laser annealing (col.7 lines 1-17 of Hostetler) includes scanning (this is commonly known in laser annealing processes) entire contact face (300 of Hostetler/602 of Goller) with the laser beam (201 of Hostetler) using a step-and-repeat type (plurality of pulses col.7 lines 1-17 of Hostetler) of scanning.
Re claim 9: Goller in view of Hostetler teach the method according to claim 7, wherein the laser beam (201 of Hostetler) has a footprint (d3 of Hostetler) on the contact face (top surface of 300 of Hostetler/602 of Goller), and the laser annealing (col.7 lines 1-17 of Hostetler) the contact face (top surface of 300 of Hostetler/602 of Goller), includes scanning (this is commonly known in laser annealing processes) the contact face (top surface of 300 of Hostetler/602 of Goller) so that two adjacent irradiated portions (as shown in fig.3b and 3c of Hostetler) of the contact face (top surface of 300 of Hostetler/602 of Goller), have approximately zero mutual overlap (the process is repeated only until desired pattern is irradiated col 6, lines 23-29).
Re claim 10: Goller in view of Hostetler teach the method according to claim 7, wherein the laser beam (201 of Hostetler) has an energy density (5-10 J/cm^2, col 8 lines 30-31 of Hostetler) higher than 3 J/cm2.
Claim 5 is rejected under 35 U.S.C. 103 as being unpatentable over Goller as applied to claim 4.
Re claim 5: The method according to claim 4, wherein the abrasive surface has a mesh size between about 1500 and about 500.
Goller teaches the method according to claim 4.
Goller is silent to explicitly teach the abrasive surface having a mesh size between about 1500 and about 500.
It would have been obvious to one of ordinary skill in the art before the effective filing date for the abrasive surface to have a mesh size between about 1500 and about 500 since mesh size requirements to grind SiC layers are commonly known to range from 30-10000 mesh depending on the finish and material hardness requirements for the device during manufacturing.
Claim 11 is rejected under 35 U.S.C. 103 as being unpatentable over Goller as applied to claim , and in further view of Joshi (US 20118/0174840 A1)
Re claim 11: Goller teaches method according to claim 1, further comprising depositing a metallization layer .
Goller is silent to explitly teach depositing a metallization layer on the silicide layer.
Joshi teaches (fig.9) depositing a metallization layer (302) on the silicide layer (layer of 305)
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to include the metallization layer as taught by Joshi in the device of Goller in order to have the predictable result of improving conductivity in the device and ultimately improving performance of the semiconductor device.
Claims 13-14 are rejected under 35 U.S.C. 103 as being unpatentable over Joshi as applied to claim 12.
Re claim 13: Joshi teaches the device according to claim 12,
Joshi is silent to explicitly teach wherein the threshold is about 2000 protrusions/mm2.
However, Joshi teaches the first protrusions (bigger sized- 300) can contain different horizontal and identical vertical extensions while also differing in size (par. 97-98).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to make the threshold of Joshi about 2000 protrusions/mm^2 depending on the density requirements in the manufacturing process of the device as having more protrusions/mm^2 would have the predictable result of improved current flow and thermal stability and overall improve the efficiency and performance of a semiconductor device such as devices with ohmic contacts.
Re claim 14: Joshi teaches the device according to claim 12, wherein each first protrusion (bigger-sized 300) of the plurality of first protrusions (bigger-sized 300) has a size (par.56 mentions 350 can have vertical range between 2 nm and 1 µm which comprises 300) between about 0.5 µm and about 2 µm.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to RICKY VERDES whose telephone number is (703)756-1401. The examiner can normally be reached Monday - Friday 07:30 - 03:30 PM.
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, Jessica Manno can be reached on (571) 272-2339. 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.
/RICKY VERDES/Examiner, Art Unit 2898
/JESSICA S MANNO/SPE, Art Unit 2898