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 claims 2, 5, 6 and 7 in the reply filed on 05/06/2026 is acknowledged. The traversal is on the ground(s) that species a and b at least share a “special technical feature” that defines a contribution over the prior art. This is not found persuasive because species a) and b) have difference is forming the green body such as dry pressing vs. tape casting.
The requirement is still deemed proper and is therefore made FINAL.
Claim Rejections - 35 USC § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
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.
The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
Claim(s) 2, 5 and 7 is/are rejected under 35 U.S.C. 103 as being unpatentable over Ning Xiaoshan (JP 2005330178 A) (hereinafter Xiaoshan) in view of Ye Feng (CN 108585881 A) (hereinafter Feng) and further in view of Yusen Duan “Cost effective preparation of Si3N4 ceramics with improved thermal conductivity and mechanical properties” Publication date: 05 October 2019 (hereinafter Duan).
Regarding claim 2, Xiaoshan discloses a method for preparing a silicon nitride ceramic material, comprising: a suitable amount of a rare earth compound and a relatively low-melting-point compound powder such as MgO were added to commercially available silicon nitride powder as a sintering aid, and the mixture was mixed in a ball meal for 24 hours to prepare the raw material powder. a suitable amount of a rare earth compound and a relatively low-melting-point compound powder such as MgO were added to commercially available silicon nitride powder as a sintering aid, and the mixture was mixed in a ball meal for 24 hours to prepare the raw material powder. The sintering temperature is 1400 to 1800°C, preferably 1500 to 1600°C, the holding time is preferably within 10 minutes. The ceramics are then heated to 1600-2000⁰C in a nitrogen atmosphere of 1 MPa and held at that temperature for 1-5 hours. Xiaoshan discloses at least one of silicon powder and silicon nitride powder as original powder and Y2O3 powder and MgO powder as sintering aids (¶007-¶0012).
Xiaoshan is silent about the row material are mixed in a protective atmosphere; the molar ratio of Y2O3 to MgO and the structure and properties of the final product and production of green body.
Feng also discloses a method for preparing a silicon nitride ceramic material. The method comprising: 1st step, the silicon nitride powder deoxidation treatment, natural cooling, and the resulting silicon nitride powder grinding and sieving; 2nd step, silicon powder and sintering additive are mixed in the medium under the action of the mixing, drying after the end of the mixing, sieving, get the powder; 3rd step, the pressing the powdery row, get the silicon nitride ceramic green body; 4th step, the silicon nitride ceramic green body pressure sintering, get the silicon nitride ceramic material (¶009-0014). Feng discloses various modification to improve the process such better, 1st step for the deoxidation process, the silicon nitride powder and carbon powder are respectively put into different in the crucible, is placed in the tube, in order to 5 -10 °C/min of the rate of rise of temperature, in the reaction atmosphere in the 1200 °C -1400°C temperature processing 4 - 8 H. Better, the reaction atmosphere is nitrogen gas or ammonia gas. Better, the 2nd step silicon powder, the rare earth oxide with the alkaline earth metal compound in a molar ratio of 95 - 89:4 - 6:1 – 5. Feng discloses the green body is subjected to gas pressure sintering with nitrogen as the sintering atmosphere to obtain silicon nitride ceramic material (¶0015-¶0024). The benefit of doing so would have been to reduce the oxygen content of the original powder; in the sintering process to reduce the lattice oxygen content higher degree, more help to avoid phonon scattering, thereby improving the thermal conductivity of the silicon nitride ceramic.
Given the wealth of knowledge it would have been obvious to a person of ordinary skill in the art to utilize Fengs method of making a silicon nitride ceramic within the method of preparing a silicon nitride ceramic material. The benefit of doing so would have been to improve the thermal conductivity of the silicon nitride ceramic.
Xiaoshan and Feng are both silent about a molar ratio of Y2O3 to MgO.
Duan also discloses a method silicon nitride ceramics. The method discloses the raw materials and silicon powder, Y2O3 to MgO with a molar ration of Y2O3 to MgO of 2:5. Before sintering, nitriding is carried out in a mixed atmosphere at 1400⁰C for 2 hours, and then the temperature is increased to 1450⁰C for 6 hours (Page 2, Experiment procedure section). The benefit of doing so would have been to produce a silicon nitride ceramics with both high thermal conductivity and excellent mechanical properties by using Y2O3 to MgO as sintering additives.
Given the wealth of knowledge, it would have been obvious to a person of ordinary skill in the art to utilize Duan within the method of manufacturing silicon nitride ceramic as taught by the combined teaching of Xiaoshan and Feng. The benefit of doing so would have been to produce silicon nitride ceramics with both high thermal conductivity and excellent mechanical properties.
Regarding claim 5, Xiaoshan discloses the sintering temperature is 1400 to 1800°C, preferably 1500 to 1600°C, the holding time is preferably within 10 minutes. The ceramics are then heated to 1600-2000⁰C in a nitrogen atmosphere of 1 MPa and held at that temperature for 1-5 hours. Thus, a person of ordinary skill can readily adjust the temperature and pressure to obtain desired final properties of silicon nitride ceramic.
Regarding claim 7, Feng discloses wherein the time of the pretreatment is 3 to 5 hours (¶0020).
Claim(s) 6 is/are rejected under 35 U.S.C. 103 as being unpatentable over Xiaoshan, Feng and Duan as applied to claims 2, 5 and 7 above, and further in view of Han Yoon Soo (KR 20170135105 A) (hereinafter Soo).
Regarding claim 6, the limitations of claim 1 are taught by the combined teaching of Xiaoshan, Feng and Duan as cited above. They are both silent about the use of tape-casting and polyvinyl butyral.
Soo also discloses a method manufacturing silicon nitride substrate. The method discloses preparing ceramics raw materials including Si powder, Y2O3 powder and MgO powder; mixing the ceramics raw materials, a solvent, an organic (polyvinyl butyral), a dispersing agent and a plasticizer to form slurry; forming a sheet type molded product in a tape casting method using the slurry; laminating the molded products in a plurality of layers and performing compression to form a laminated sheet; degreasing the laminated sheet in an oxidizing atmosphere in order to minimize an amount of residual oxygen and carbon; nitriding the degreased laminated sheet; and sintering the nitrided laminated sheet. The present invention can manufacture the sheet type substrate with thin thickness at low costs using the tape casting method and perform degreasing treatment in the oxidizing atmosphere and performing nitriding treatment in an N2 atmosphere to minimize the amount of residual oxygen and carbon, thereby enhancing mechanical properties, particularly fracture toughness, high temperature properties and thermal conductivity of a silicon nitride sintered body, obtaining high quality silicon nitride (Si3N4) sintered body via reaction sintering, and lowering shrinkage even after nitridation by the reaction sintering to manufacture elaborate shapes (Abstract).
Given the wealth of knowledge, it would have been obvious to a person of ordinary skill in the art to utilize tape-casting method and use polyvinyl butyral as taught by Soo within the method of manufacturing a silicon nitride ceramic material as taught by the combined teaching of Xiaoshan, Feng and Duan. The benefit of doing so would have been to high quality silicon nitride sintered body via sintering and lowering shrinkage even after nitridation by the reaction sintering to manufacture elaborate shapes.
Conclusion
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/VISHAL I PATEL/Primary Examiner, Art Unit 1746
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