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, 4-8, 16 and 19 are rejected under 35 U.S.C. 103 as being unpatentable over Chen et al. (CN 107322187-A, hereafter “Chen”, of record) in view of Liu et al. (CN 114029651-A, “Liu”, see attached document), and further in view of The Brazing Book by Lucas-Milhaupt (see attached NPL, 2017).
Regarding claims 1-2, Chen discloses an active solder paste composition for cladding ceramic (abstract, background), the composition comprising: 85-90 wt% metal powder with the balance 10-15 wt% being a binder/ flux [0008, 0018], wherein the metal powder comprises about 4 wt% first metal powder (titanium hydride powder) and 82 wt% of a second metal copper-silver alloy powder, on the basis of the total weight of the solder paste composition [0027-0028] - the respective amount falls within claimed ranges 1-10 wt% first metal powder and 75-94 wt% of second metal powder.
Chen discloses powder diameter range including 20 micron, but does not mention average of 1-6 micron for the titanium hydride powder. However, such size is known in the art. Liu (also directed to titanium-containing active brazing filler- abstract) teaches titanium hydride powder average particle diameter (D50) preferably being 0.1-30 microns [0007], which overlaps with the recited range. The weight content of titanium hydride in the mixed filler powder is preferably 0.1 to 15% [0011], which falls within the recited range of 1-20 wt% and is also similar to Chen. 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. Liu ‘651 discloses that the titanium hydride as titanium source solves the problem of titanium being easy to be oxidized and provides the benefit of slowly decomposing and high active titanium [0015]. Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to include titanium hydride powder average particle diameter of about 1-5 microns in the solder paste of Chen because doing so would result in beneficial effects of slowly decomposing the titanium hydride and high active titanium, as suggested by Liu.
Chen discloses copper-based alloys including copper-silver alloy, but is silent with respect to phosphorus. However, having phosphorus & silver constituents in filler is known in the art. Brazing book (NPL) discloses brazing filler composition comprising copper-based alloys, including silver and phosphorus, known by tradename Sil-Fos (see pg. 36 table)- specifically, Sil-Fos 6 alloy (also known as BCuP-4 by AWS classification) contains 6-7 wt% phosphorus, 5-6 wt% silver and the remainder copper (see pg. 38 table), which meets claimed phosphorus and silver amounts. The BCuP alloy is self-fluxing on copper due to phosphorus content, reducing surfaces oxides and improving wetting. Brazing book further teaches that the Sil-Fos 6 alloy has low melting range and provides ideal fluid filler for close fit-up work (pg. 36). Accordingly, it would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to utilize BCuP-4 copper-phosphorus-silver alloy in the paste of Chen because it provides low melting point and doing so would result in self-fluxing, thereby reducing surfaces oxides and improving wetting for joining with copper.
Thus, Chen as modified by Liu & Brazing Book above discloses recited paste composition with two metal powders and renders the claims obvious.
As to claim 4, Chen discloses the solder paste composition having content of 1-20 wt% first metal powder and 80-99 wt% second metal powder, on the basis of the total weight of the first and second metal powders [0027-0028].
As to claim 5, Chen discloses that on the basis of the total weight of the active solder paste composition, the total content of the first metal powder and the second metal powder is 85-90 wt% [0018], which meets the recited range of 75-95 wt%.
As to claim 6, Chen discloses that metal powder average grain particle size ranges from about 20-100 µm ([0021], claim 3), which meets particle size of 10-30 µm for the second metal powder. Chen as modified by Liu in claim 1 above discloses titanium hydride metal powder with average particle size of 1-5 µm. In the case where the claimed ranges “overlap or lie inside ranges disclosed by the prior art” a prima facie case of obviousness exists, MPEP 2144.05.
As to claims 7-8, Chen discloses that the binder/flux in the paste composition comprises solvent(s)/dispersant(s), adhesive(s)/binder(s), and an anti-settling agent (thixotropic agent); wherein the dispersant or solvent is one or more selected from dibutyl phthalate, terpineol and butyl carbitol acetate (about 50-70 wt% solvent), the dispersant or solvent is polyethylene glycol (about 10-15 wt%), wherein the binder is one or more selected from ethyl cellulose, polyvinyl alcohol, and combinations thereof, and wherein the anti-settling agent (2-5 wt%) is one or more selected from hydrogenated castor oil and polyamide wax [0022-0025, 0029, 0032] – the amounts of flux constituents overlap or are close enough with recited respective ranges. Moreover, it would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to select claimed constituents within the flux in the solder paste of Chen in order to tailor the paste to achieve desired thixotropic properties.
As to claim 16, Chen as modified by the Brazing book (NPL) in claim 1 above discloses that the second metal powder (BCuP-4 by AWS classification) contains 6-7 wt% phosphorus, 5-6 wt% silver and the remainder copper and thus, renders the claim obvious.
As to claim 19, Chen discloses the solder paste composition having content of 1-20 wt% first metal powder and 80-99 wt% second metal powder, on the basis of the total weight of the first and second metal powders [0027-0028].
Claims 3 and 17-18 are rejected under 35 U.S.C. 103 as being unpatentable over Chen in view of Liu & Brazing book as applied to claim 2 above, and further in view of Beeferman et al. (US 5186380, “Beeferman”).
As to claims 3 and 17-18, Chen discloses mixing titanium hydride powder [0027], which typically includes 90 wt% or higher titanium. Nonetheless, using titanium for active metal brazing/soldering has been well recognized in the art. Beeferman teaches that active metal brazing of ceramics has been greatly developed since the 1940s wherein an active component such as titanium or zirconium chemically reacts with the ceramic to form an interfacial compound, thereby improving wettability. As one example, old patent no. 2,570,248 discloses titanium hydride (TiH2) with a powdered copper solder for bonding non-metallic bodies (Background- col. 1, lines 36-60). Commercial titanium hydride (TiH2) powder is known to include ≥99 wt% titanium to promote wetting. Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to provide ≥93-96 wt% content of titanium within titanium hydride powder in the solder paste of Chen & Liu with a motivation to promote wettability during bonding with a ceramic member.
Response to Amendment and Arguments
Applicant’s arguments with respect to amended claim(s) 1-2 have been fully considered but are moot in light of new grounds of rejection set forth above. Current 103 rejection now includes new references of Liu & Brazing book (NPL) and addresses the revised matter specifically challenged in the arguments.
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.
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/DEVANG R PATEL/
Primary Examiner, AU 1735
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