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 .
Election/Restrictions
Applicant's election with traverse of species A, 1, and c in the reply filed on 12 November 2025 is acknowledged. The traversal is on the ground that the core metal layer in figures 1, 3-5, 7-9, and 11-12 is homogeneous. This is not found persuasive because the combined construction varies across the species in these figures as outlined in the restriction requirement.
The requirement is still deemed proper and is therefore made FINAL. Accordingly, claims 3, 4, and 9-20 have been withdrawn.
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, and 5 are rejected under 35 U.S.C. 103 as being unpatentable over Adelmann et al (US 5,355,281 A, hereinafter “Adelmann”), in view of Schulz-Harder (EP 0862209 A2, hereinafter “Schulz-Harder”), and further in view of Sasaki et al (WO 9854761 A1, hereinafter “Sasaki”)
Regarding Claim 1 – Adelmann discloses a ceramic metal composite substrate, comprising: a metal core layer (30, col. 2, lines 50-51 and Fig. 1) having two metallic surfaces spaced apart from each other along a thickness direction by a predetermined thickness (thickness of 30, col. 3, lines 19-20), wherein the metal core layer is made of a material including copper (col. 2, lines 50-51); wherein each of the two ceramic covering layers overlaps at least 80% of an area of the corresponding metallic surface along the thickness direction (Ceramic layers overlap 100% in Fig. 1).
Although Adelmann discloses the metal and ceramic layers are solderable, Adelmann fails to expressly disclose two soldering layers respectively formed on the two metallic surfaces of the metal core layer; and two ceramic covering layers fixed to the metal core layer through the two soldering layers, respectively.
However, Schulz-Harder discloses a soldering layer (4 Schulz-Harder [0009] and Fig. 1) formed on the metallic surface of the metal core layer (6 Schulz-Harder [0006] and Fig. 1); and a ceramic covering layer (2 Schulz-Harder [0006] and Fig. 1) fixed to the metal core layer through the soldering layer (Schulz-Harder Fig. 1).
Schulz-Harder discloses a metal-ceramic substrate analogous to Adelmann. Schulz-Harder teaches the use of soldering paste for the connection of metal and ceramic layers for the benefit of being able to use screen printing technology to cover a large area (Schulz-Harder [0018]). Therefore, it would have been obvious to one of ordinary skill in the art prior to the effective filing date of the claimed invention to use soldering paste to connect metal and ceramic layers for the benefit of being able to use screen printing to cover a large area.
Adelmann fails to explicitly disclose each of the two ceramic covering layers has a heat-transfer coefficient being greater than or equal to 20 W/m-k, and a sum of thicknesses of the two ceramic covering layers and thicknesses of the two soldering layers is less than or equal to the predetermined thickness.
However, Sasaki discloses each of the two ceramic covering layers has a heat-transfer coefficient being greater than or equal to 20 W/m-k ([0067]), and a sum of thicknesses of the two ceramic covering layers and thicknesses of the two soldering layers is less than or equal to the predetermined thickness (Thicknesses of ceramic and conductor layers are set to satisfy the relationship y (=) (0.5)x + 0.48 [0088], and soldering layers ideally kept below 40 µm [0130]).
Sasaki discloses a heat sink structure with stacked layers analogous to Adelmann. Sasaki teaches using aluminum nitride ceramic with thermal conductivity above 20 W/m-k for the benefit of sufficient heat dissipation while having a layer thick enough for mechanical strength ([0070]). Sasaki further teaches keeping the layer thicknesses of ceramic layers and conductor layers in the right proportions to reduce warping and increase reliability ([0088]), and keeping solder layers thin to maximize peel strength and minimize component warpage ([0130]). Therefore, it would have been obvious to one of ordinary skill in the art prior to the effective filing date of the claimed invention to use aluminum nitride ceramic with thermal conductivity above 20 W/m-k for the benefit of sufficient heat dissipation while having a layer thick enough for mechanical strength, to keep thicknesses of ceramic layers and conductor layers in the right proportions to reduce warping and increase reliability, and to keep solder layers thin to maximize peel strength and minimize component warpage.
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Regarding Claim 2 – Adelmann modified by Schulz-Harder, and further modified by Sasaki, discloses all the limitations of claim 1.
The combination of Adelmann, Schulz-Harder and Sasaki further discloses the metal core layer is a copper layer, a copper-tungsten alloy layer, or a copper-molybdenum alloy layer (Adelmann column 2, lines 50-51), and each of the two ceramic covering layers is an aluminum nitride (AlN) layer that is sintered to the metal core layer through the corresponding soldering layer and that has a thickness being within a range from 30 µm to 350 µm (0.2-2.0 mm Schulz-Harder [0007], which is an overlapping range, presenting a prima facie case of obviousness. See MPEP 2144.05(I)).
Regarding Claim 5 – Adelmann modified by Schulz-Harder, and further modified by Sasaki, discloses all the limitations of claim 1.
The combination of Adelmann, Schulz-Harder and Sasaki further discloses each of the two soldering layers is a brazing paste or a glass paste(Schulz-Harder [0009]), and a thickness of any one of the two ceramic covering layers is greater than or equal to a thickness of the corresponding soldering layer that is less than or equal to 30 µm (Ceramic layers 0.2-2.0 mm, Schulz-Harder [0007], and soldering layer 0.005-0.01 mm, Schulz-Harder [0021]).
Claims 6-7 are rejected under 35 U.S.C. 103 as being unpatentable over Adelmann et al (US 5,355,281 A, hereinafter “Adelmann”), in view of Schulz-Harder (EP 0862209 A2, hereinafter “Schulz-Harder”), and further in view of Sasaki et al (WO 9854761 A1, hereinafter “Sasaki”), and further in view of Schulz-Harder et al (WO 2013097845 A1, hereinafter “Schulz-Harder2”)
Regarding Claim 6 – Adelmann modified by Schulz-Harder, and further modified by Sasaki, discloses all the limitations of claim 1.
The combination of Adelmann, Schulz-Harder and Sasaki fails to disclose each of the two ceramic covering layers has a grinding plane arranged away from the metal core layer.
However, Schulz-Harder2 discloses the outer surfaces of ceramic layers have a grinding plane (Schulz-Harder2 [0014]).
Schulz-Harder2 discloses a copper-ceramic substrate analogous to Adelmann. Schulz-Harder2 teaches grinding as an option to remove surface oxide to provide an appropriate surface for sputtering a copper film (Schulz-Harder2 [0014] and [0033]). Therefore, it would have been obvious to one of ordinary skill in the art prior to the effective filing date of the claimed invention to remove surface oxide by grinding to gain the benefit of an appropriate surface for sputtering a copper film.
Regarding Claim 7 – Adelmann modified by Schulz-Harder, and further modified by Sasaki and Schulz-Harder2, discloses all the limitations of claim 6.
The combination of Adelmann, Schulz-Harder, Sasaki, and Schulz-Harder2 further discloses two circuit layers respectively formed on the grinding planes of the two ceramic covering layers in a direct plated copper (DPC) manner or in a thin film metallized substrates manner (by sputtering, Schulz-Harder2 [0033]).
Claim 8 is rejected under 35 U.S.C. 103 as being unpatentable over Adelmann et al (US 5,355,281 A, hereinafter “Adelmann”), in view of Schulz-Harder (EP 0862209 A2, hereinafter “Schulz-Harder”), and further in view of Sasaki et al (WO 9854761 A1, hereinafter “Sasaki”), and further in view of Schulz-Harder et al (WO 2013097845 A1, hereinafter “Schulz-Harder2”), and further in view of Dilsch et al (WO 2017060224 A1, hereinafter “Dilsch”).
Regarding Claim 8 – Adelmann modified by Schulz-Harder, and further modified by Sasaki and Schulz-Harder2, discloses all the limitations of claim 7.
The combination of Adelmann, Schulz-Harder, Sasaki, and Schulz-Harder2 fails to disclose at least one of the two ceramic covering layers has a thru-hole that is recessed from the grinding plane thereof to the corresponding soldering layer, and a corresponding one of the two circuit layers is filled in an entirety of the thru-hole so as to be connected to the corresponding soldering layer.
However, Dilsch discloses at least one of the two ceramic covering layers has a thru-hole (11, Dilsch [0020] and Fig. 2) that is recessed from the grinding plane thereof to the corresponding soldering layer (5, Dilsch [0019] and Fig. 2), and a corresponding one 7, Dilsch [0021] and Fig. 2) of the two circuit layers is filled in an entirety of the thru-hole so as to be connected to the corresponding soldering layer (Dilsch Fig. 2]).
Dilsch discloses a metal and ceramic layer stack analogous to Adelmann. Dilsch teaches using copper-filled vias through an aluminum nitride substrate (6, Dilsch [0021]) for additional thermal coupling to remove waste heat as well as the further benefit of selective electrical coupling to a heat sink (Dilsch [0021]). Therefore, it would have been obvious to one of ordinary skill in the art prior to the effective filing date of the claimed invention to consider combing the teachings of Adelmann and Dilsch to use copper vias through aluminum nitride ceramic layers for the further benefit of enhanced thermal transportation of waste heat and the establishment of an electrical connection to a metal heat sink.
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Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to JASON MCDONALD whose telephone number is (571) 272-5944. The examiner can normally be reached M-F 7:30a-5p Eastern, alternating Fridays out of office.
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/JASON MCDONALD/Examiner, Art Unit 2898 /DALE E PAGE/Supervisory Patent Examiner, Art Unit 2899