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 .
Continued Examination Under 37 CFR 1.114
A request for continued examination under 37 CFR 1.114, including the fee set forth in 37 CFR 1.17(e), was filed in this application after final rejection. Since this application is eligible for continued examination under 37 CFR 1.114, and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114. Applicant's submission filed on December 31, 2025 has been entered.
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.
Claims 1-2 and 4-12 are rejected under 35 U.S.C. 103 as being unpatentable over US 2020/0211850 A1 to Donofrio et al. (hereinafter “Donofrio” – previously cited reference) in view of US 2017/0355041 A1 to Yamashita et al. (hereinafter “Yamashita” – previously cited reference).
Regarding claim 1, Donofrio discloses a method of manufacturing a gallium nitride substrate, the method comprising:
preparing a gallium nitride wafer having a first main surface and a second main surface on a side opposite from the first main surface (GaN crystal prepared having opposing first and second sides; Figs. 7 and 19; paragraphs [0151], [0190], [0224]), the gallium nitride wafer made of a hexagonal crystal, each of the first main surface and the second main surface being a {1-100} m-plane of the hexagonal crystal (GaN crystal having hexagonal crystal structure with opposing surfaces along m-plane thereof; paragraph [0151]);
forming a transformation layer along a planar direction of the gallium nitride wafer, by emitting a laser beam into the gallium nitride wafer (laser tool 29 used to form subsurface damage 40 in a plane of GaN crystal along a desired direction from one of the opposing sides; Figs. 7 and 19; paragraphs [0151], [0190], [0224]); and
forming the gallium nitride substrate from the gallium nitride wafer, by dividing the gallium nitride wafer at the transformation layer as a boundary (GaN substrate formed by dividing the GaN crystal along the subsurface damage layer 40 of Fig. 7 or layer 268 of Fig. 19; paragraphs [0190], [0224]), wherein, in the forming of the transformation layer, the laser beam is emitted to form an irradiation mark for forming the transformation layer in the gallium nitride wafer (subsurface damage layer 40 forms visual marks denoting where damage was done by laser tool 29; Figs. 7 and 19; paragraphs [0190], [0224]), in the forming of the transformation layer, the laser beam is scanned in a direction as a scanning direction parallel to the second main surface of the gallium nitride wafer to form the irradiation mark while an angle formed between the scanning direction and an a-axis direction of the gallium nitride wafer is set to be smaller than 60 degrees, and the a-axis direction is a [0010] direction (laser tool 29 scanned along any desired direction in various patterns such as concentric circles encompassing scanning directions at all angles relative the a-axis, including the [0010] a-axis direction, and along one of the opposing surfaces of GaN crystal parallel to an a-axis direction in linear scanning movement 54 to form subsurface damage 40 visual marks; Figs. 7, 8B-8D and 19; paragraphs [0190]-[0191], [0224])..
Donofrio fails to disclose forming a transformation layer along a planar direction of the gallium nitride wafer, by emitting a laser beam into the second main surface of the gallium nitride wafer.
However, Yamashita discloses forming a transformation layer along a planar direction of the gallium nitride wafer, by emitting a laser beam into the second main surface of the gallium nitride wafer (YAG laser 310 used to create cracks in a planar direction of a GaN wafer along machined spots by emitting the beam into the m-plane thereof; Fig. 2; paragraphs [0023]-[0025], [0027], [0041]).
Donofrio and Yamashita are considered to be analogous to the claimed invention because they are in the same field of semiconductor wafer fabrication techniques. Therefore, it would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to have modified Donofrio to incorporate the teaching of Yamashita in order to potentially provide increased yield from each ingot, enhances wafer flatness for subsequent epitaxial growth, and more efficient crack propagation and separation.
Regarding claim 2, Donofrio in view of Yamashita discloses the method according to Claim 1. Donofrio further discloses further comprising: flattening at least one of two surfaces of a divided gallium nitride wafer acquired after the dividing of the gallium nitride wafer (surface of GaN substrate ground using CMP after divided from GaN crystal; Fig. 19; paragraph [0224]).
Regarding claim 4, Donofrio in view of Yamashita discloses the method according to Claim 1. Donofrio further discloses wherein, in the forming of the transformation layer, the laser beam is scanned in a direction as a scanning direction parallel to the second main surface of the gallium nitride wafer to form the irradiation mark while an angle formed between the scanning direction and the a-axis direction of the gallium nitride wafer is set to be smaller than 50 degrees (laser tool 29 scanned along any desired direction in various patterns such as along one of the opposing surfaces of GaN crystal parallel to an a-axis direction in linear scanning movement 54 to form subsurface damage 40 visual marks; Figs. 7, 8B and 19; paragraphs [0190]-[0191], [0224]).
Regarding claim 5, Donofrio in view of Yamashita discloses the method according to Claim 1. Donofrio further discloses wherein, in the forming of the transformation layer, the laser beam is scanned in a direction as a scanning direction parallel to the second main surface of the gallium nitride wafer to form the irradiation mark while an angle formed between the scanning direction and the a-axis direction of the gallium nitride wafer is set to be smaller than 30 degrees (laser tool 29 scanned along any desired direction in various patterns such as along one of the opposing surfaces of GaN crystal parallel to an a-axis direction in linear scanning movement 54 to form subsurface damage 40 visual marks; Figs. 7, 8B and 19; paragraphs [0190]-[0191], [0224]).
Regarding claim 6, Donofrio in view of Yamashita discloses the method according to Claim 1. Donofrio further discloses wherein the gallium nitride wafer includes an epitaxial layer having a first n-type doped layer and a second n-type doped layer (one or more n-type epitaxial layers may be grown on GaN substrate; paragraph [0151]), and the first n-type doped layer has a higher impurity concentration than the second n-type doped layer (one of the n-type epitaxial layers may be intentionally doped while the other n-type epitaxial layer may be unintentionally doped which creates a doping differential between the two layers; paragraph [0151]).
Regarding claim 7, Donofrio in view of Yamashita discloses the method according to Claim 1. Donofrio fails to disclose wherein, in the forming of the transformation layer, a wafer transformation layer is formed along the planar direction of the gallium nitride wafer after chip transformation layers are formed at different positions in a thickness direction of the gallium nitride wafer along a separation line.
However, Yamashita discloses wherein, in the forming of the transformation layer, a wafer transformation layer is formed along a planar direction of the gallium nitride wafer after chip transformation layers are formed at different positions in a thickness direction of the gallium nitride wafer along a separation line (cutting scheduled planes 100, altered regions 12, and auxiliary altered regions 22 are formed in GaN wafer in different directions at different positions and at different times in order to separate the wafer along those regions and planes to form multiple semiconductor devices; Figs. 1, 2 and 5; paragraphs [0020], [0023], [0039]-[0041]).
Donofrio and Yamashita are considered to be analogous to the claimed invention because they are in the same field of semiconductor wafer fabrication techniques. Therefore, it would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to have modified Donofrio to incorporate the teaching of Yamashita in order to potentially provide lower separation stress, enhanced crack propagation uniformity, and improved surface quality and flatness.
Regarding claim 8, Donofrio in view of Yamashita discloses the method according to Claim 7. Donofrio fails to disclose nitrogen generated by the forming of the wafer transformation layer is released to outside through pores of the chip transformation layers, thereby reducing strain or defect in each of chip formation regions of the gallium nitride wafer.
However, Yamashita discloses nitrogen generated by the forming of the wafer transformation layer is released to outside through pores of the chip transformation layers, thereby reducing strain or defect in each of chip formation regions of the gallium nitride wafer (GaN wafer exposed to YAG laser for forming cracks creates decomposition of GaN which allows for nitrogen gas to escape through the cracks which is capable of reducing strain or defect within the GaN wafer; paragraphs [0027], [0035], [0038], [0040]-[0041]).
Donofrio and Yamashita are considered to be analogous to the claimed invention because they are in the same field of semiconductor wafer fabrication techniques. Therefore, it would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to have modified Donofrio to incorporate the teaching of Yamashita in order to potentially provide maximized wafer yield, uniform plane formation, and minimized subsurface damage.
Regarding claim 9, Donofrio in view of Yamashita discloses the method according to Claim 1. Donofrio further discloses wherein the gallium nitride wafer is divided into a base wafer and a recycled wafer in the dividing of the gallium nitride wafer, and the base wafer is used for forming the gallium nitride substrate, the method further comprising: forming another gallium nitride substrate from the recycled wafer, after the dividing of the gallium nitride wafer (GaN wafer formed from substrate 220 where substrate is returned to beginning of process to form another GaN wafer from the remaining substrate 220A; Figs. 19-20; paragraphs [0224]-[0225]).
Regarding claim 10, Donofrio in view of Yamashita discloses the method according to Claim 1. Donofrio further discloses wherein, in the forming of the transformation layer, the laser beam is scanned in a direction as a scanning direction parallel to the second main surface of the gallium nitride wafer to form the irradiation mark while an angle formed between the scanning direction and the a-axis direction of the gallium nitride wafer is set to be in a range of 0 to 20 degrees (laser tool 29 scanned along any desired direction in various patterns such as along a direction across one of the opposing surfaces of GaN crystal parallel, i.e. an angle of 0 degrees, to an a-axis direction in linear scanning movement 54 to form subsurface damage 40 visual marks; Figs. 7, 8B and 19; paragraphs [0190]-[0191], [0224]).
Regarding claim 11, Donofrio in view of Yamashita discloses the method according to Claim 1. Donofrio further discloses wherein the scanning direction and the a-axis direction are not parallel to each other (laser tool 29 scanned along any desired direction in various patterns such as concentric circles encompassing scanning directions at all angles relative the a-axis; Figs. 7, 8B-8D and 19; paragraphs [0190]-[0191], [0224]).
Regarding claim 12, Donofrio in view of Yamashita discloses the method according to Claim 1. Donofrio further discloses wherein in the forming of the transformation layer, the laser beam is scanned in a direction as a scanning direction parallel to the second main surface of the gallium nitride wafer to form the irradiation mark while an angle formed between the scanning direction and the a-axis direction of the gallium nitride wafer is set to be 10 degrees or larger (laser tool 29 scanned along any desired direction in various patterns such as concentric circles encompassing scanning directions at all angles relative the a-axis and along one of the opposing surfaces of GaN crystal parallel to an a-axis direction in linear scanning movement 54 to form subsurface damage 40 visual marks; Figs. 7, 8B-8D and 19; paragraphs [0190]-[0191], [0224]).
Response to Arguments
Applicant's arguments filed January 26, 2026 have been fully considered. Applicant presents substantive amendments to claim 1 and adds new claims 11-12 with corresponding arguments that the amendments overcome the previous 35 USC 103 rejection of Donofrio in view of Yamashita. Specifically, Applicant argues that Donofrio only discloses laser scanning along the [1120] direction. However, Examiner’s analysis for original claim 3 pointed to the fact that Figs. 8b-8d as described in paragraph [0191] show laser tool 29 scanned along any desired direction in various patterns such as concentric circles encompassing scanning directions at all angles relative the a-axis, even if those movements are desired to be in linear scanning movements 54. By scanning in circles, the laser tool 29 necessarily scans at every angle within the 360 degree circular movement relative the a-axis, and further relative the [0010] direction regarding amended claim 1. By that same logic, new claims 11 and 12 are also disclosed by Donofrio as outlined above.
Conclusion
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/IAN DEGRASSE/Examiner, Art Unit 2818
/JEFF W NATALINI/Supervisory Patent Examiner, Art Unit 2818