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 .
Specification
The objection to the title is withdrawn in view of applicants’ submission of a replacement title.
Claim Rejections - 35 USC § 112
The 35 U.S.C. 112(b) rejection of claims 1-7 is withdrawn in view of applicants’ claim amendments.
Claim Rejections - 35 USC § 103
The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action.
Claims 1-6 is/are rejected under 35 U.S.C. 103 as being unpatentable over Japanese Patent Appl. Publ. No. JP 2019073425 A to Yoshida, et al. (hereinafter “Yoshida”) in view of U.S. Patent Appl. Publ. No. 2011/0101502 to Shaoping Wang (“Wang”) and further in view of U.S. Patent Appl. Publ. No. 2016/0186361 to Koukitu, et al. (“Koukitu”).
Regarding claim 1, Yoshida teaches a method for manufacturing a group III nitride substrate (see the Abstract, Figs. 1-7, and Description of Embodiments section which teach a method of manufacturing a GaN substrate (10)), the method comprising:
forming group III nitride films having a group III element face on a surface thereof, on both surfaces of a substrate selected from the group consisting of a Si <111> substrate, a sapphire substrate, a SiC substrate, a GaAs substrate, and a SCAM (ScAlMgO4) substrate, so as to produce a group III nitride film carrier (see Fig. 1 and section (1) on the Configuration of GaN substrate at pp. 1-2 which teach the use of a vapor deposition method to grow a GaN film (11) on a sapphire substrate to produce a carrier; see specifically p. 2 and 4 which teach that the Ga-polar surface of the GaN film (11) is formed facing outwards from the underlying sapphire substrate such that the Ga-polar surface is in contact with the support substrate (12) after being transferred);
performing ion implantation to the group III nitride film on at least one surface of both surfaces of the group III nitride film carrier, so as to form an ion-implanted region in the group III nitride film (see p. 2 of section (1) which teaches that the GaN film (11) is cut out from the sapphire base substrate; see also the section on Modification 2 at pp. 9-10 which teaches the use of a hydrogen embrittlement process such as Smart Cut to remove a portion of the bonding surface; accordingly, a person of ordinary skill in the art prior to the effective filing date of the invention would be motivated to use ion implantation to remove a thin and uniform portion of the single crystal GaN layer (11) such that it may be transferred to the base substrate (12) since this would involve nothing more than the use of a known cutting technique according to its intended use);
adhering the group III nitride film having been subjected to the ion implantation of the group III nitride film carrier to a base substrate comprising polycrystals comprising a group III nitride as a major component, so as to bond the group III nitride film carrier to the base substrate (see Fig. 1, pp. 2-4 of section (1), and section (2) at pp. 4-5 which teach that the GaN film (11) is bonded to the base substrate (12) which is produced by growing polycrystalline GaN onto a different base substrate such that the base substrate (12) is comprised of polycrytalline GaN as a major component);
spacing the group III nitride film carrier from the base substrate to transfer the ion-implanted region of the group III nitride film to the base substrate, so as to form a group III nitride film having an N face on a surface thereof on the base substrate (see Fig. 1 and p. 2 of section (1) which teaches that the GaN film (11) is separated from the sapphire substrate and is transferred to the GaN polycrystalline base substrate (12) to produce the GaN substrate (10) which is part of the Smart Cut process disclosed in Modification 2 at pp. 9-10; moreover p. 2 teaches that the exposed surface (10a) is the N-polar surface due to its improved properties, including a resistance to thermal decomposition compared to the Ga-polar face); and
forming a group III nitride film on the group III nitride film having an N face on a surface thereof on the base substrate by a THVPE method, so as to produce a thick film of a group III nitride film (see Figs. 2-3 and section (3) at pp. 5-7 which teach the use of THVPE to epitaxially grow a GaN crystal (20) in the N-polar plane direction to produce a thick GaN crystal (20)).
Yoshida does not teach that the Group III nitride film is formed on both surfaces of the substrate when producing the group III nitride film carrier. However, in Figs. 1-3 and ¶¶[0024]-[0047] as well as elsewhere throughout the entire reference Wang teaches a method of depositing a high quality epitaxial GaN layer (14) onto a sapphire substrate (12) which exhibits minimal bow. As discussed specifically in Fig. 1A and ¶[0025] the presence of wafer bow due to the coefficient of thermal expansion (CTE) mismatch between the GaN epitaxial layer (14) and sapphire substrate (12) may be alleviated by depositing a GaN layer (14) of equal thickness on the top and bottom surfaces of the sapphire substrate (12) such that the effects due to the CTE mismatch are essentially cancelled out. Thus, a person of ordinary skill in the art prior to the effective filing date of the invention would be motivated to deposit the GaN film (11) in the method of Yoshida on both surfaces of the sapphire substrate with equal thicknesses in order to minimize the effects of wafer bow due to a CTE mismatch between the film and substrate.
Yoshida and Wang do not teach that the thick film is a film having a thickness of 15 mm or more. However, in Figs. 10 & 13 and ¶¶[0083]-[0122] as well as elsewhere throughout the entire reference Koukitu teaches an analogous system and method for depositing high quality GaN epitaxial layers by THVPE at appreciable growth rates. In Fig. 13 and ¶[0113] Koukitu specifically teaches the growth of a thick GaN single crystal layer having a thickness of 1 cm or more or 5 cm or more in order to facilitate slicing the bulk GaN crystal into a larger number of GaN substrates. Thus, a person of ordinary skill in the art prior to the effective filing date of the invention would look to the teachings of Koukitu and would be motivated to utilize THVPE to epitaxially grow the thick GaN crystal (20) in the method of Yoshida and Wang to a thickness of greater than 15 mm in order to produce a larger number of GaN single crystal wafers from a single crystal GaN ingot, thereby making the crystal growth process more cost-efficient. The combination of prior art elements according to known methods to yield predictable results has been held to support a prima facie determination of obviousness. All the claimed elements are known in the prior art and one skilled in the art could combine the elements as claimed by known methods with no change in their respective functions, with the combination yielding nothing more than predictable results to one of ordinary skill in the art. KSR International Co. v. Teleflex Inc., 550 U.S. 398, __, 82 USPQ2d 1385, 1395 (2007). See also, MPEP 2143(A).
Regarding claim 2, Yoshida teaches that the group III nitride film having a group IIl element face on a surface thereof is a GaN film having a Ga face on a surface thereof (see Fig. 1 and section (1) at pp. 1-2 which teach that the film (11) is comprised of GaN with p. 2 and 4 specifically teaching that the Ga-polar surface of the deposited GaN film (11) is formed facing outwards from the underlying sapphire substrate).
Regarding claim 3, Yoshida teaches that the base substrate is a polycrystalline GaN (P-GaN) substrate (see Fig. 1, pp. 2-4 of section (1), and section (2) at pp. 4-5 which teach that the base substrate (12) is produced by growing polycrystalline GaN onto a different base substrate such that the base substrate (12) is comprised of polycrystalline GaN as a major component).
Regarding claim 4, Yoshida teaches that the group III nitride film formed on the group III nitride film having an N face on a surface thereof on the base substrate is a GaN film (see Figs. 2-3 and section (3) at pp. 5-7 which teach the use of THVPE to epitaxially grow a GaN crystal (20) in the N-polar plane direction to produce a thick GaN crystal (20)).
Regarding claim 5, Yoshida teaches that the base substrate is a substrate that is obtained by forming the polycrystals on a PBN substrate by a vapor phase epitaxy method (see pp. 2-3 of section (1) which teach the use of a vapor phase epitaxy method to deposit a polycrystalline GaN layer onto a PBN substrate in order to form the base substrate (12)).
Regarding claim 6, Yoshida teaches that the vapor phase epitaxy method is a THVPE method (see pp. 2-3 of section (1) which teach that any known vapor phase method may be used to produce the GaN polycrystal layer (12) with Fig. 2 and section (3) at pp. 5-6 teaching that THVPE is a known technique for growing high quality GaN layers; accordingly a person of ordinary skill in the art would be motivated to utilize THVPE to grow the polycrystalline GaN base substrate (12) to produce a higher quality base substrate; moreover, the use of THVPE would involve nothing more than the use of a known growth technique according to its intended use).
Claim 7 is/are rejected under 35 U.S.C. 103 as being unpatentable over Yoshida in view of U.S. Patent Appl. Publ. No. 2002/0197825 to Usui, et al. (“Usui”) and further in view of Wang and still further in view of Koukitu.
Regarding claim 7, Yoshida teaches that the step of producing the group III nitride film carrier includes forming the group III nitride films having a group III element face on a surface thereof by an MOCVD method (see Fig. 1 and section (1) at pp. 1-2 which teach the use of a vapor deposition method to grow a GaN film (11) on a sapphire substrate to produce a carrier with p. 7 of section (4) teaching that MOCVD may be used to deposit the GaN layers; accordingly a person of ordinary skill in the art would be motivated to utilize MOCVD to grow the GaN film (11) since this would involve nothing more than the use of a known growth technique according to its intended use).
Yoshida does not teach that the group III nitride film carrier produced by the step of producing the group III nitride film carrier has a curvature radius of 10 m or more. However, in at least Figs. 1-2 and ¶¶[0097]-[0101] Usui teaches an analogous method of depositing a GaN layer (4) onto a sapphire substrate (1) by MOCVD through the use of a Ti mask (2’). The use of the mask (2’) along with a GaN seed layer (3) prior to performing MOCVD growth of GaN layer (4) promotes a reduction in the defect density and helps to alleviate bowing arising from the thermal coefficient of expansion mismatch between the sapphire substrate and GaN. As specifically disclosed in ¶[0100] this results in a radius of curvature of about 20 m which falls within the claimed range of 10 m or more. Thus, a person of ordinary skill in the art prior to the effective filing date of the invention would be motivated to utilize the method of Usui to deposit a GaN film having a radius of curvature of greater than 10 m in order to produce a higher quality GaN layer with fewer defects for use in the method of Yoshida.
Yoshida and Usui do not teach that the Group III nitride carrier film is formed on both surfaces of the substrate by an MOCVD method, so that the difference between the thickness of the Group III nitride film formed on one surface of the substrate and the thickness of the Group III nitride film formed on the other surface of the substrate is 0.5 mm or less. However, as noted supra with respect to the rejection of claim 1, in Figs. 1-3 and ¶¶[0024]-[0047] as well as elsewhere throughout the entire reference Wang teaches a method of depositing a high quality epitaxial GaN layer (14) onto a sapphire substrate (12) which exhibits minimal bow. As discussed specifically in Fig. 1A and ¶[0025] the presence of wafer bow due to the coefficient of thermal expansion (CTE) mismatch between the GaN epitaxial layer (14) and sapphire substrate (12) may be alleviated by depositing a GaN layer (14) of equal thickness on the top and bottom surfaces of the sapphire substrate (12) such that the effects due to the CTE mismatch are essentially cancelled out. Thus, a person of ordinary skill in the art prior to the effective filing date of the invention would be motivated to deposit the GaN film (11) in the method of Yoshida on both surfaces of the sapphire substrate with equal thicknesses (i.e., a thickness difference of zero) in order to minimize the effects of wafer bow due to a CTE mismatch between the film and substrate.
Response to Arguments
Applicant's arguments filed December 22, 2025, have been fully considered but they are not persuasive.
Applicants argue that Yoshida does not teach or suggest that the Group III nitride film having been subject to ion implantation is adhered to a base substrate containing polycrystals containing a Group III nitride as a major component because the film having been subject to ion implantation is removed from substrate (11) or (12) and is not adhered to the substrate (11) or (12). See applicants’ 12/22/2025 reply, p. 7. Applicants’ argument is noted, but is unpersuasive. It is noted that the rejection of claim 1 is under 35 U.S.C. 103 which means that it is based on what would have been obvious to a person of ordinary skill in the art. In at least Modification 2 at pp. 9-10 Yoshida specifically teaches that a hydrogen embrittlement process such as the Smart Cut process is known in the art and in this process ion implantation is utilized to define a cleavage plane such that a thin and uniform portion of a single crystal substrate may be removed. In order to form a uniform hydrogen embrittlement layer by ion implantation it is necessarily performed the ion implantation process before the single crystal is bonded to a handle substrate as otherwise implantation of the ions will be blocked by the handle substrate. Moreover, since the cleaved layer typically is very thin and may not be entirely self-supporting, it is desirable to first bond the single crystal that has been subject to ion implantation to the handle substrate prior to initiating the cleavage process. In this manner the thin cleaved layer may be readily supported by a thicker handle substrate such that it may be transported and handled without being damaged. It therefore is the Examiner’s position that a person of ordinary skill in the art would utilize the Smart Cut process disclosed in Modification 2 at pp. 9-10 of Yoshida to first perform ion implantation on the GaN film (11) and then bond the GaN film (11) to the substrate (12) in the manner shown in Fig. 1 of Yoshida such that it functions as a handle substrate and facilitates cleavage of a thin layer from the GaN film (11). This process is also shown in U.S. Patent No. 9,650,723 to D’Evelyn, et al. (hereinafter “D’Evelyn”) which was cited as pertinent prior art of record and teaches a method of transferring a crystalline GaN donor layer to a CTE-matched polycrystalline handle substrate. This is specifically illustrated in at least Figs. 1A-1C of D’Evelyn where an ion damaged layer (103) is first formed in a GaN donor substrate (101) which is then bonded to a handle substrate (117) followed by detachment of a thin crystalline layer (106) from the GaN donor substrate (101) to produce a bonded composite (120).
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.
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/KENNETH A BRATLAND JR/Primary Examiner, Art Unit 1714