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 .
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 4-18 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 emitting a laser beam into the second main surface of the gallium nitride wafer, and an output of the laser beam to form the irradiation mark is 2.0 micro Joules or less.
However, Donofrio already discloses emitting the laser beam into a surface of gallium nitride wafer (see paragraph [0190]), and adjusting the laser output power generally for desired parameters of the subsurface laser damage lines (see paragraph [0189]).
Further, 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]), and an output of the laser beam to form the irradiation mark is 2.0 micro Joules or less (sub-nanosecond pulsed 532 nm YAG laser 310 used having wavelength below the bandgap of GaN so the beam can be focused inside the crystal with a tight focus to form 0.2 micron width line-shaped modified region, which is known to use pulse energies of less than 1 micro Joule while still forming subsurface damage in GaN wafers, particularly given paragraph [0035] teaches grouped-line patterns making cracks easier to propagate which allows for even further reduced pulse energy relative conventional methods; Fig. 2; paragraphs [0023]-[0025], [0027], [0035], [0041]). This is further evidenced by Tanaka et al. (see attached NPL document) Smart-cut-like laser slicing of GaN substrate using its own nitrogen. Sci Rep 11, 17949 (2021) which demonstrates use of 532 nm sub-nanosecond laser with 0.6 micro Joule pulses to form an internal crack plane within a GaN wafer.
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, enhanced wafer flatness for subsequent epitaxial growth, more efficient crack propagation and separation, and reduced surface irregularities along surfaces exposed by fracturing due to reduced laser output power.
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]).
Regarding claim 13, Donofrio in view of Yamashita discloses the method according to Claim 1. Donofrio further discloses wherein the scanning direction is a first direction, and in the forming of the transformation layer, the laser beam is scanned along the first direction; after being scanned along the first direction, the laser beam is shifted in a second direction orthogonal to the first direction and then scanned along the first direction, so that the irradiation mark is formed (laser is scanned along first direction 52, shifted in a direction orthogonal to first direction 52 and then scanned along first direction 52 again; Figs. 8A-8D).
Regarding claim 14, Donofrio in view of Yamashita discloses the method according to Claim 1. Donofrio further discloses wherein the irradiation mark is one of a plurality of irradiation marks, and forming the irradiation mark comprises simultaneously forming multiple irradiation marks of the plurality of irradiation marks by emitting the laser beam (laser processing station configured to produce multiple subsurface laser damage regions simultaneously; paragraph [0100]).
Regarding claim 15, Donofrio in view of Yamashita discloses the method according to Claim 1. Donofrio further discloses wherein the scanning direction is a linear direction (direction 52 is linear; Fig. 8A).
Regarding claim 16, Donofrio in view of Yamashita discloses the method according to Claim 1. Donofrio further discloses wherein the scanning direction is a linear direction (direction 52 is linear; Fig. 8A).
Regarding claim 17, Donofrio in view of Yamashita discloses the method according to Claim 1. Donofrio fails to disclose wherein the output of the laser beam to form the irradiation mark is 1.0 micro Joule or less.
However, Donofrio already discloses adjusting the laser output power generally for desired parameters of the subsurface laser damage lines (see paragraph [0189]).
Further, Yamashita discloses wherein the output of the laser beam to form the irradiation mark is 1.0 micro Joule or less (sub-nanosecond pulsed 532 nm YAG laser 310 used having wavelength below the bandgap of GaN so the beam can be focused inside the crystal with a tight focus to form 0.2 micron width line-shaped modified region, which is known to use pulse energies of less than 1 micro Joule while still forming subsurface damage in GaN wafers, particularly given paragraph [0035] teaches grouped-line patterns making cracks easier to propagate which allows for even further reduced pulse energy relative conventional methods; Fig. 2; paragraphs [0023]-[0025], [0027], [0035], [0041]). This is further evidenced by Tanaka et al. Smart-cut-like laser slicing of GaN substrate using its own nitrogen. Sci Rep 11, 17949 (2021) which demonstrates use of 532 nm sub-nanosecond laser with 0.6 micro Joule pulses to form an internal crack plane within a GaN wafer.
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 reduced surface irregularities along surfaces exposed by fracturing due to reduced laser output power.
Regarding claim 18, 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]), the irradiation mark is one of a plurality of irradiation marks, and forming the irradiation mark comprises simultaneously forming multiple irradiation marks of the plurality of irradiation marks by emitting the laser beam (laser processing station configured to produce multiple subsurface laser damage regions simultaneously; paragraph [0100]).
Donofrio fails to disclose emitting a laser beam into the second main surface of the gallium nitride wafer.
However, Donofrio already discloses emitting the laser beam into a surface of gallium nitride wafer (see paragraph [0190]).
Further, 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, enhanced wafer flatness for subsequent epitaxial growth, and more efficient crack propagation and separation.
Response to Arguments
Applicant's arguments filed June 29, 2026 have been fully considered. Applicant presents substantive amendments to claim 1 and adds new claims 13-18 with corresponding arguments. Specifically, Applicant asserts that Yamashita does not disclose the language amended into claim 1. However, Yamashita discloses all of the physical laser parameters that would enable output power pulses of 1.0 micro Joule or less to form subsurface crack planes in GaN wafers, as evidenced by Tanaka et al., which, in further view of paragraph [0035] of Yamashita and paragraph [0189] of Donofrio, renders the related limitations obvious in view of Donofrio and Yamashita. Further, Applicant asserts that Donofrio does not disclose the new limitations introduced into new claims 13-16 and 18. However, Donofrio discloses linear scanning in a direction, shifting in an orthogonal direction, and simultaneous formation of plural subsurface laser damage lines. Therefore, claims 1-2 and 4-18 are obvious over Donofrio in view of Yamashita.
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.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to IAN DEGRASSE whose telephone number is (571) 272-0261. The examiner can normally be reached Monday through Friday 8:30a until 5:00p.
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, JEFF NATALINI can be reached on (571) 272-2266. 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. 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.
/IAN DEGRASSE/Examiner, Art Unit 2818
/JEFF W NATALINI/Supervisory Patent Examiner, Art Unit 2818
Prosecution Insights