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 .
Response to Arguments
Applicant’s arguments filed 9/30/26 with respect to the rejection of claim(s) 1-2 under Chen in view of Liu & Brazing book have been fully considered and are found persuasive. Therefore, previous rejection has been withdrawn. However, upon further consideration, a new ground(s) of rejection is made in light of new references of Kelley, Takeshima and Goldberg set forth below.
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 1-5 and 16-19 are rejected under 35 U.S.C. 103 as being unpatentable over Kelley (US 2570248) in view of Takeshima et al. (JP H05-70260-A, hereafter “Takeshima”, see attached document), and further in view Goldberg et al. (US 3930306, hereafter “Goldberg”).
Regarding claim 1, Kelley discloses an active solder paste composition for bonding/cladding nonmetallic bodies (i.e. ceramic) with metal (col. 1, lines 1-5; claim 3), the composition comprising: a powdered mixture of titanium hydride (first metal powder) and solder such as copper powder (second metal powder) and a binder/flux (col. 1, lines 25-30; col. 2, lines 1-15).
Kelley is silent with respect to amount of titanium hydride & its particle size, and amount of second metal powder. However, such active paste content is known in the art. Takeshima (directed to brazing filler metal paste for joining ceramics- title) also discloses joining of ceramic to a metal with a paste mixture containing copper, silver, titanium hydride (TiH2), and organic substance/flux, wherein amount of TiH2 is about 2-20 wt% based on the mixture, with the mixture having uniform fine powder size of 1-3 µm average particle diameter (abstract; [0008-0009], [0012]) - this falls within the recited range of 1-20 wt% TiH2 having a median particle size D50 of 1-6 µm. For instance, examples 3-4 shows 10 wt% TiH2 and 90 wt% solder metal powder (Table 1; [0014]). 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. Takeshima teaches that such uniform paste of fine powders eliminates poor bonding at the bonding surface between the ceramic and the metal, and avoids localized non-uniformity in the bondability, thereby increasing bonding strength [0010, 0019]. Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to modify the active paste composition of Kelly with fine powders of titanium hydride and solder metal with recited amounts because doing so would eliminate poor bonding at the bonding surface between the ceramic and the metal, and avoid localized non-uniformity in the bondability, resulting in increased bonding strength as suggested by Takeshima.
Kelley or Takeshima does not mention the second metal powder including 4-6 wt% silver and 4-10 wt% phosphorus. Takeshima discloses using the active paste for joining ceramic-metal substrates used in semiconductor IC packages and power diodes [0001]. Similarly, Goldberg discloses a brazing alloy for joining ceramic and metal members of semiconductor devices (abstract; col. 1, lines 5-9; col. 2, lines 5-9). Goldberg teaches the brazing alloy comprising about 80-89% copper, 5-15% silver and about 4-6% phosphorus on a weight basis (col. 2, lines 50-55; col. 4, lines 55-65), which meets the claimed ranges. Similar to Kelley, Goldberg teaches that in the brazing alloy, copper constitutes the main component, with the silver and the phosphorus lowering the wetting point of the composition to a temperature usable in connection with semiconductor devices, and the phosphorus also providing necessary fluxing action (col. 7, lines 6-12). Accordingly, it would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to incorporate silver and phosphorus amounts of about 5-6% in the second metal powder of Kelley in order to lower the wetting point of the composition as well as to provide fluxing action, with a motivation of joining connections in forming semiconductor devices, as suggested by Goldberg.
Thus, combination of Kelley, Takeshima and Goldberg above discloses an active solder paste comprising about 2-20 wt% titanium hydride, 80-90% copper-based Cu-Ag-P alloy and at least 0.1 wt% binder/flux, wherein the titanium hydride has a median particle size D50 of 1-6 µm. Examiner also points out that “for cladding ceramic with copper” (lines 1-2) is an intended use of the claimed composition, which is not limited to cladding and also useful to mix with another substance.
As to claim 2, Kelly as modified by Goldberg above discloses 4-6 wt% phosphorus in the Cu-Ag-P alloy.
As to claims 4-5, Kelley as modified by Takeshima in claim 1 above discloses the solder paste composition having content of 2-20 wt% first metal powder (TiH2) and 80-98 wt% second metal powder (Cu-Ag-P alloy), on the basis of total weight of the first and second metal powders.
As to claim 16, Kelley as modified by Goldberg in claim 1 above discloses that the second metal powder (Cu-Ag-P alloy) contains 80-89% copper, 5-6 wt% silver and 5-6 wt% phosphorus, and thus renders the claim obvious.
As to claims 3 and 17-18, active metal brazing of ceramics has been well-established art and ordinary skilled artisan would readily recognize that an active component such as titanium or zirconium chemically reacts with the ceramic to form an interfacial compound, thereby improving wettability. Commercial titanium hydride (TiH2) powder is known to include ≥95 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 active paste of Kelley, Takeshima and Goldberg with a motivation to promote strong wettability during bonding.
As to claim 19, Kelley as modified by Takeshima in claim 1 above discloses the solder paste composition having content of 2-20 wt% first metal powder (TiH2) and 80-98 wt% second metal powder (Cu-Ag-P alloy), on the basis of total weight of the first and second metal powders.
Claims 6-8 are rejected under 35 U.S.C. 103 as being unpatentable over Kelley in view of Takeshima & Goldberg as applied to claim 1 above, and further in view Chen et al. (CN 107322187-A, hereafter “Chen”, of record).
As to claim 6, Kelley as modified by Takeshima above discloses first metal powder (titanium hydride) with a median particle size D50 of 1-6 µm, but lacks a median particle size D50 of 10-30 µm for the second metal powder. However, such size is known in the art. Chen discloses an active solder paste composition for cladding ceramic (abstract, background), the composition comprising: 85-90 wt% metal powder as well as 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]. Chen teaches that metal powder average grain particle size ranges from about 20-100 µm ([0021], claim 3), which overlaps with recited particle size of 10-30 µm for the second metal powder. 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. A person of ordinary skill in the art would have found it obvious to utilize about 10-20 µm average particle size for the second metal powder in the combination of Kelley, Takeshima and Goldberg since such particle size is within common knowledge and suitable for active paste, as evidenced by Chen.
As to claims 7-8, Kelley or Takeshima does not specifically disclose all of recited flux components. However, Chen teaches 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. Consequently, one would have reasonable expectation of success in assisting and promoting wetting during joining with a ceramic. 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 active solder paste of Kelley, Takeshima and Goldberg with a motivation to tailor the paste to achieve desired thixotropic properties.
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
