DETAILED ACTION
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 1-13 and 15 are rejected under 35 U.S.C. 103 as being unpatentable over Kawahara et al., US 2020/0216659 A1, in view of Aikyo, JP201503657 (A), cited herein according to the machine translation provided by Applicant.
Regarding claims 1 and 4-7, Kawahara teaches a liquid composition comprising a thermosetting epoxy resin ([0022], [0076]-[0078]), a solvent ([0090]), first silica particles having a media diameter d50 size of 1-20 microns ([0047]-[0048], [0054]), and additional silica particles having a diameter of less than 1 micron ([0072]) or more than 1 micron ([0063]), either of which may correspond to the claimed “second” silica particles.
The teachings of Kawahara differ from the present invention in that Kawahara does not teach that the product of the specific surface area of the first particles to the diameter of the first particles may be 2.7-5 microns m2/g. Aikyo, however, teaches the use of silica particles with a specific surface area of 3.5-5.5 m2/g when making such thermosetting resins in order to achieve good moldability ([0014]). It would have been obvious to one of ordinary skill in the art to provide the 1-20 micron first silica particles of Kawahara with a specific surface area of 3.5-5.5 m2/g in order to create a product with good moldability, which would result in the product of the specific surface area of the first particles and the diameter of the first particles being in the range of 0.175 – 5.5 microns m2/g. Note that when a claimed range overlaps with or lies inside a range disclosed by the prior art, a prima facie case of obviousness exists (MPEP 2144.05 I).
Regarding claims 2 and 3, although Kawahara expresses the content of silica filler in the resin in terms of volume % rather than mass, Kawahara teaches that the first silica particles may be present in an amount of 5-35 vol % ([0057]) and the second silica particles may be present in an amount of 25-60 vol % ([0070]), equating to a total silica content of 30 – 95 vol % and ratio of first particles to second particles of 0.08 – 1.4, which overlaps in scope with the claimed ranges based on the respective densities of silica and epoxy resin.
Regarding claim 8, Kawahara teaches that the resin may be an epoxy resin ([0078]-[0079).
Regarding claim 9, although Kawahara does not teach any specific solvents, Aikyo teaches that methyl ethyl ketone may be used as a solvent in such thermosetting epoxy resins ([0028]). It would have been obvious to one of ordinary skill in the art to use methyl ethyel ketone as the solvent of Kawahara because Aikyo explicitly teaches methyl ethyl ketone to be appropriate for use as a solvent in such resin compositions.
Regarding claim 10-13 and 15, Kawahara teaches that the resin composition may be used to make semi-cured prepregs for circuit boards via impregnation of the resin into fibrous substrates, which may then be fully cured and laminated to a copper foil and etched to form a wiring board ([0005]-[0007], [0010]-[0013], [0036]).
Claim 14 is rejected under 35 U.S.C. 103 as being unpatentable over Kawahara and Aikyo, as applied above, and further in view of Uno et al., US 2012/0285734 A1.
Regarding claim 14, Kawahara teaches a laminate metal substrate as discussed above. The teachings of Kawahara differ from the present invention in that Kawahara does not teach any specific maximum height roughness for the copper foil of the laminate (ie, does not teach a roughness of less than 2 microns). Uno, however, teaches that copper foils in such laminates should have a maximum surface roughness of 1.1 microns or less in order to achieve formability of fine circuit patterns and signal transmission properties in the high frequency (Abstract, [0050]). It would have been obvious to one of ordinary skill in the art to provide the copper foil of Kawahara with a roughness of less than 1.1 microns, because doing so would achieve formability of fine circuit patterns and signal transmission properties in the high frequency.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to Ian A Rummel whose telephone number is (571)270-5692. The examiner can normally be reached Monday - Thursday and alternating Fridays, 8:30-5:00.
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/IAN A RUMMEL/ Primary Examiner, Art Unit 1785
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