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 and 6-10 are rejected under 35 U.S.C. 103 as being unpatentable over Endo et al. (JP 2020-164894 A, see attached translation, hereafter “Endo”) in view of Anai et al. (WO 2020/202971, hereafter “Anai”). US patent 12,070,801 is taken to be faithful English translation of the above WO ‘971 document for convenience and portions cited below refer to the US patent.
Regarding claims 1 and 10, Endo discloses a method for producing a joined body in which a first joining target and a second joining target are joined with a joining layer interposed between the first joining target and the second joining target [0016], the method comprising: a step of applying a paste that contains copper particles [0014, 0027] and an organic solvent [0037-0038] to the first joining target (metal substrate) to form a coating film [0015, 0046]; a step of placing the second joining target (semiconductor element- [0048]) on the coating film to form a stack [0016-0017]; and a sintering step of heating and pressing the stack to sinter the copper particles contained in the coating film to form the joining layer [0053], wherein, in the sintering step, the heating is performed incrementally from a heating start temperature to a highest temperature (e.g. sintering temperature 280°C [0054]), and the pressing is performed incrementally from a pressing start pressure to a highest pressure, and control is performed in such a manner that a pressing pressure is 5 MPa or less [0056] (meets 15 MPa or less) when a heating temperature reaches 200°C. Examiner notes that any manner of increasing temperature & pressure meets ‘incrementally’- present claims are not limited to particular timing conditions. The sintering temperature and pressure conditions in the method of Endo falls within the recited ranges. In the case where the claimed ranges “overlap or lie inside ranges disclosed by the prior art” a prima facie case of obviousness exists. In re Woodruff, 919 F.2d 1575, 16 USPQ2d 1934 (Fed. Cir. 1990), MPEP 2144.05.
Endo does not mention particle size and non-spherical copper particles, however, such particle size and shape is known in the art. Anai (also directed to bonding material and bonded structure) discloses a bonding material, used in bonding to a bonding target (col. 3, lines 13-23), comprising copper powder particles having a plurality of shapes selected from a combination of spherical shape, flat shape, dendritic (tree-like) shape, rod-like or the like (col. 4, lines 56-65). Anai teaches spherical particles having a particle size D50 of 0.1-0.2 µm (col. 5, lines 28-41) and similarly, non-spherical particles having a particle size D50 of 0.3-0.4 µm (col. 5, lines 49-67), wherein such particle size provides a bonded structure having both good heat resistance & high bonding strength, as well as forming a dense sintered structure at a relatively low temperature (col. 5, lines 32-41, 55-63) – the particle size meets the claimed range(s). Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to utilize copper particles similar to Anai in the bonding method of Endo with a motivation to produce joined structure having both good heat resistance & high bonding strength, as well as forming a dense sintered structure at a relatively low temperature. Thus, Endo as modified by Anai discloses copper particle having both spherical and non-spherical shape with recited particle size.
As to claims 6-7, Endo discloses that the highest temperature Tm is 280°C [0054], which meets the recited range of 200-350°C, and holding at this constant temperature for about 10-60 minutes for bonding strength [0055].
As to claims 8-9, Endo discloses that the highest pressure is 5 MPa [0054], which meets the recited range of 1-40 MPa, and holding at this constant pressure for about 10-60 minutes during sintering for bonding strength [0055].
Claim 2 is rejected under 35 U.S.C. 103 as being unpatentable over Endo in view of Anai as applied to claim 1 above, and in view of Hiratsuka et al. (US 2015/0069638, hereafter “Hiratsuka”).
As to claim 2, Endo does not specifically show that the coating film extends from peripheral edges of the second joining target when the second joining target is placed on the coating film. However, such arrangement is known in the sintering art. Analogous to Endo, Hiratsuka is also drawn to metallic paste for bonding semiconductor devices such as power device (abstract, [0003]). Hiratsuka shows that a bonding/coating film 6 is applied in such a manner that the coating film 6 has dimensions that the coating film extends from peripheral edges of the second joining target 5 (SiC chip) when the second joining target is placed on the substrate 7 (see fig. 8, [0090]); the coating film/paste is formed into a size and shape suitable for the bonding portion [0064]. Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to provide a coating film extending from peripheral edges of the second joining target in the joining method of Endo with a motivation to ensure sufficient coverage of the joining layer at the interface.
Claims 3-5 are rejected under 35 U.S.C. 103 as being unpatentable over Endo in view of Anai as applied to claim 1 above, and in view of Jo et al. (The properties of Cu sinter paste for pressure sintering”, IEEE conference, 2019, NPL, hereafter “Jo”).
As to claims 3-4, Endo is silent with respect to the sintering step not including a constant temperature process for 10 seconds or more from the heating start temperature to the highest temperature. However, such continuous heating is known in the art. Jo (NPL- also directed to sintering using metal paste- abstract) teaches copper paste for pressure sintering (pg. 76), wherein the sintering step gradually heats from room temperature (RT) to 280°C in 2 min and does not include a constant temperature process for 10 seconds or more from a start temperature (RT) to the highest temperature 280°C (see fig. 4). After reaching 280°C, Jo teaches applying 9 MPa pressure under nitrogen for sintering for 5 minutes (pg. 77). In this manner, highest pressure is applied after reaching the highest temperature. Consequently, Jo discloses that the copper paste sintering achieves high shear strength without oxidation (pg. 76- top right column). Accordingly, it would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to apply temperature & pressure in similar manner to Jo in the method of Endo in order to achieve desired shear strength.
As to claim 5, Jo does not disclose applying a constant pressure step for 10 seconds or more from the pressing start pressure to the highest pressure, so this negative limitation is satisfied in the combination of Endo, Anai & Jo above.
Response to Amendment and Arguments
Applicant’s arguments with respect to amended claim(s) 1-10 have been considered but are moot in light of new grounds of rejection set forth above. Current 103 rejection(s) now include new reference of Anai and addresses the matter specifically challenged in the argument.
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.
Inquiry
Any inquiry concerning this communication or earlier communications from the examiner should be directed to DEVANG R PATEL whose telephone number is (571) 270-3636. The examiner can normally be reached on Monday-Friday 8am-5pm, EST.
To schedule an interview, Applicant is encouraged to use the USPTO Automated Interview Request (AIR) at https://www.uspto.gov/patents/laws/interview-practice. Communications via Internet email are at the discretion of Applicant. If Applicant wishes to communicate via email, a written authorization form must be filed by Applicant: Form PTO/SB/439, available at www.uspto.gov/patent/patents-forms. The form may be filed via the Patent Center and can be found using the document description Internet Communications, see https://www.uspto.gov/patents/apply/forms. In limited circumstances, the Applicant may make an oral authorization for Internet communication. See MPEP § 502.03.
If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Keith Walker can be reached on 571-272-3458. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
Information regarding the status of an application may be obtained from the Patent Center. For more information, see https://patentcenter.uspto.gov. For questions, technical issues or troubleshooting, please contact the Patent Electronic Business Center at ebc@uspto.gov or 1-866-217-9197 (toll-free).
/DEVANG R PATEL/
Primary Examiner, AU 1735
Prosecution Insights