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 .
Continued Examination Under 37 CFR 1.114
A request for continued examination under 37 CFR 1.114, including the fee set forth in 37 CFR 1.17(e), was filed in this application after final rejection. Since this application is eligible for continued examination under 37 CFR 1.114, and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114. Applicant's submission filed on 09/03/2025 has been entered.
This action is responsive to Applicant's amendments/remarks filed 09/03/2025.
Claims 1-3, 5, 6 and 9-13 are currently pending and under examination.
The rejection of claims 1, 3-6, and 9-13 under 35 U.S.C. 103 as being unpatentable over Suzumura (WO 2020/137086 A1, published on July 2, 2020, hereinafter Suzumura) in view of Takahashi (US 5,981,641 A, hereinafter Takahashi), Ito (EP 2194581 A1, hereinafter Ito), and Ding (CN 104098914 B, hereinafter Ding) is withdrawn in view of the above amendments.
The rejection of claim 2 under 35 U.S.C. 103 as being unpatentable over Suzumura (WO 2020/137086 A1, hereinafter Suzumura) in view of Takahashi (US 5,981,641 A, hereinafter Takahashi), Ito (EP 2194581 A1, hereinafter Ito), and Ding (CN 104098914 B, hereinafter Ding), and further in view of Liu (US 2018/0323130 A1, hereinafter Liu) is withdrawn in view of the above amendments.
The following rejections and/or objections are either reiterated or newly applied. They constitute the complete set presently being applied to the instant application.
Claim Rejections - 35 USC § 103
The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action.
1. Claims 1, 3, 5, 6, and 9-13 are rejected under 35 U.S.C. 103 as being unpatentable over Suzumura (WO 2020/137086 A1, published on July 2, 2020, hereinafter Suzumura) in view of Takahashi (US 5,981,641 A, hereinafter Takahashi), Ito (EP 2194581 A1, hereinafter Ito), Otsuka (JP 2020073621 A, hereinafter Otsuka), and Ding (CN 104098914 B, hereinafter Ding).
Regarding claim 1, Suzumura teaches a thermally conductive composition comprising a matrix resin, and thermally conductive particles (para [0005]), wherein per 100 parts by weight of the matrix resin component,
(a) 900 parts by mass or more of aluminum nitride (the claimed aluminum nitride particles (B-1)) having an average particle diameter of 50 μm or more (para [0005]), which overlaps with the claimed range of "50 μm or more and 150 μm or less";
(b) 400 parts by mass or more of aluminum nitride having an average particle diameter of 5 μm or less;
(c) more than 0 parts by mass and 400 parts by mass or less of alumina (the claimed metal oxide (B-3) other than zinc oxide) having an average particle diameter of 6 μm or less (para [0005]), which overlaps with the claimed range of "1 μm or more and less than 20 μm"; and
(d) 350-500 parts by mass of aluminum nitride (the claimed aluminum nitride particles (B-2)) having an average particle diameter of more than 5 μm and less than 50 μm (para [0015]), which overlaps with the claimed range of "15 μm or more and less than 50 μm".
Thus, based on the total amount of the thermally conductive composition in Suzumura, the thermally conductive particles can have a content of more than 95% by mass, which overlaps with the claimed range of "70 to 98% by mass".
Based on the total amount of the thermally conductive particles in Suzumura, (a) aluminum nitride with an average particle diameter of 50 μm or more (the claimed aluminum nitride particles (B-1)) can have a content of 34% by mass to 64% by mass, which falls within the claimed range of "30 to 75% by mass"; (d) aluminum nitride with an average particle diameter of more than 5 μm and less than 50 μm (the claimed aluminum nitride particles (B-2)) can have a content of 13% by mass to 26% by mass, which falls within the claimed range of "10 to 30% by mass"; (c) alumina with an average particle diameter of 6 μm or less (the claimed metal oxide (B-3) other than zinc oxide) can have a content of 3% by mass to 19% by mass, which overlaps with the claimed range of "5 to 15% by mass".
Suzumura teaches that the matrix resin component includes organopolysiloxane (component (A1)) and organohydrogenpolysiloxane (component (A2)) (para [0019]), and the alkenyl group in component (A1) and the SiH group in component (A2) are subjected to an addition reaction (hydrosilylation) to form a cured product (para [0029]). Thus, the matrix resin component of Suzumura reads on the claimed curable silicone resin (A). Suzumura also teaches that the viscosity of the base polymer (component (A1)) is preferably 10 to 1,000,000 mPa·s at 25 °C for desirable workability (para [0020]), equaling to 0.01 to 1000 Pa·s.
Suzumura teaches that the silane coupling agent covers the surfaces of the thermally conductive particles (surface treatment), allows the thermally conductive particles to be easily incorporated into the matrix resin, prevents the curing catalyst from being adsorbed on the thermally conductive particles, and thus has the effect of preventing cure inhibition (para [0011]). Suzumura also teaches that the silane coupling agent is R(CH3)aSi (OR')3-a, R is a C1-20 unsubstituted or substituted organic group, R' is a C1-4 alkyl group, a is 0 or 1 (para [0036]), which reads on the claimed silane coupling agent having an alkyl group having 10 to 22 carbon atoms.
Suzumura teaches that the average particle size means D50 (median diameter) in a volume-based cumulative particle size distribution, determined by a particle size distribution measurement with a laser diffraction scattering method (para [0041]), which reads on the claimed cumulative volume-based 50% particle size.
Suzumura further teaches that a thermally conductive silicone sheet is used to improve the adhesion between the semiconductor and the heat dissipation unit, and the thermally conductive silicone sheet is required to have high thermal conductivity and softness (para [0002]); the thermally conductive composition of Suzumura has high thermal conductivity and suitable hardness (softness) to follow the unevenness of the heat generating portion and/or the heat dissipating portion (para [0004]).
Suzumura does not teach that the composition comprises zinc oxide.
However, Takahashi teaches a thermally conductive silicone composition comprising a liquid silicone (e.g., organopolysiloxanes), and a thermally conductive filler, wherein the thermally conductive filler comprises an aluminum nitride powder and a zinc oxide powder, the fillers are incorporated in a total amount from 500 to 1,000 parts by weight per 100 parts by weight of the liquid silicone, and the ratio of the zinc oxide powder to the sum total of the aluminum nitride powder and the zinc oxide powder is from 0.05 to 0.5 by weight (col. 2, ll. 60 -67; col. 3, ll. 1-2; col. 3, ll. 39-44). Thus, based on the total amount of the thermally conductive filler in Takahashi, zinc oxide has a content of 5% by mass to 50% by mass, which overlaps with the claimed range of "10 to 40% by mass".
Takahashi also teaches that the average particle size of a zinc oxide powder is in a range of 0.2 to 5 μm (col. 9, ll. 17-19), which overlaps with the claimed range of "0.1 μm or more and less than 1 μm". Takahashi teaches that zinc oxide can provide thermal conductivity (col. 9, ll. 11-12). Takahashi further teaches that zinc oxide is softer than aluminum nitride, therefore, when the zinc oxide powder is used in combination with aluminum nitride powder, a soft zinc oxide particle can be arranged among hard aluminum nitride particles to function so as to confer a mobility on the close-packed structure to enable an improvement in dispensation suitability (col. 9, ll. 66-67; col. 10, ll. 1-5).
Therefore, it would have been obvious to a person of ordinary skill in the art before the effective filing date of the claimed invention to make a thermally conductive composition comprising a matrix resin and thermally conductive particles (aluminum nitride and alumina particles) as taught by Suzumura, further comprising the zinc oxide powder having an average particle size of 0.2 to 5 μm and a content of 5% by mass to 50% by mass based on the total amount of the thermally conductive filler as taught by Takahashi, in order to make the thermally conductive composition having good dispensation and good thermal conductivity with a reasonable expectation of success, because soft zinc oxide particles are arranged among hard aluminum nitride particles to confer a mobility on the close-packed structure to enable an improvement in dispensation suitability, and the zinc oxide particles also provide thermal conductivity as recognized by Takahashi.
Takahashi does not teach that the zinc oxide powder having an average particle size of 0.2 to 5 μm has a BET specific surface area of less than 9.0 m2/g.
However, Ito teaches a heat-dissipating grease composition comprising organopolysiloxane (component A) and a thermoconductive inorganic filler (component C) (abstract), wherein the thermoconductive inorganic filler is not limited as long as it has high thermal conductivity, and a specific example can be zinc oxide powder (para [0022]).
Ito teaches that the thermoconductive inorganic filler can be zinc oxide, and the zinc oxide powder has average particle diameter of 0.3 μm and specific surface of 4 m2/g (para [0036]), which fall within the range of the average particle size of the zinc oxide powder of 0.2 to 5 μm as taught by Takahashi, and also fall within the claimed ranges of "0.1 μm or more and less than 1 μm" and "less than 9.0 m2/g".
Therefore, it would have been obvious to a person of ordinary skill in the art before the effective filing date of the claimed invention to provide the zinc oxide powder having an average particle diameter of 0.3 μm and specific surface of 4 m2/g as taught by Ito as the zinc oxide powder having an average particle size of 0.2 to 5 μm in Takahashi, in order to make the composition having high thermal conductivity with a reasonable expectation of success, because the zinc oxide powder having an average particle diameter of 0.3 μm and specific surface of 4 m2/g and the zinc oxide powder having an average particle size of 0.2 to 5 μm both have good thermal conductivity as art recognized.
Furthermore, it would have been obvious to a person of ordinary skill in the art before the effective filing date of the claimed invention to use the silane coupling agent as taught by Suzumura to treat the surface of the zinc oxide particles as taught by the combination of Takahashi and Ito, in order to easily incorporate the zinc oxide particles into the matrix resin, prevent the curing catalyst from being adsorbed on the zinc oxide particles, thereby having the effect of preventing cure inhibition with a reasonable expectation of success.
Suzumura does not teach that at least one kind of aluminum nitride particles has a silica coating on a surface thereof.
However, Otsuka teaches when aluminum nitride reacts with moisture, it hydrolyzes to generate ammonia, which then transforms into aluminum hydroxide, which has low thermal conductivity; when aluminum nitride is added to resin compositions used in heat-dissipating sheets, thermal greases, and electronic component encapsulants, the ammonia generated by the hydrolysis of aluminum nitride affects the moisture resistance of the electronic components; therefore, it is necessary to improve the moisture resistance of aluminum nitride ([0002]-[0003]).
Otsuka also teaches a method for producing a silica-coated aluminum nitride particle comprising a first step of coating the surfaces of the aluminum nitride particles with an organosilicone compound, and a second step of heat-treating the aluminum nitride particles coated with the organosilicone compound after the first step at a temperature of 150 to 800 °C ([0012]), wherein the silica-coated aluminum nitride particle obtained has high thermal conductivity and excellent moisture resistance ([0035]).
Otsuka also teaches that the aluminum nitride particles used in the process have a cumulative volume d50 particle size of 0.2 µm or more and 200 μm or less ([0019]), which overlaps with the ranges of (a) aluminum nitride having an average particle diameter of 50 μm or more, (b) aluminum nitride having an average particle diameter of 5 μm or less, and (d) aluminum nitride having an average particle diameter of more than 5 μm and less than 50 μm as taught by Suzumura.
Otsuka further teaches that the silica-coated aluminum nitride particles are dispersed in a resin composition for a thermal interface material in power devices ([0057]).
Therefore, it would have been obvious to a person of ordinary skill in the art before the effective filing date of the claimed invention to coat the surface of the aluminum nitride particles as taught by Suzumura with an organosilicone compound, then heat-treat at a temperature of 150 to 800 °C as taught by Otsuka, in order to make silica-coated aluminum nitride particles, thereby improving the moisture resistance of the aluminum nitride particles while still maintaining the high thermal conductivity of the aluminum nitride particles with a reasonable expectation of success, because the silica-coated aluminum nitride particles produced in Otsuka has high thermal conductivity and excellent moisture resistance as recognized by Otsuka.
Suzumura further teaches that a thermally conductive silicone sheet is used to improve the adhesion between the semiconductor and the heat dissipation unit, and the thermally conductive silicone sheet is required to have high thermal conductivity and softness (para [0002]); the thermally conductive composition of Suzumura has high thermal conductivity and suitable hardness (softness) to follow the unevenness of the heat generating portion and/or the heat dissipating portion (para [0004]).
Suzumura does not teach that the composition further comprises a dimethyl silicone oil.
However, Ding teaches that for the heat conduction and heat dissipation effect of the heat conductive interface material on the electronic device, the interface material is required to have low hardness and high heat conductivity (p. 1, ll. 5-7), and the organosilicon thermally conductive interface material of Ding has a low hardness and high thermal conductivity (p. 1, § SUMMARY OF THE PRESENT INVENTION, ll. 21-23).
Ding teaches that the organosilicon thermally conductive interface material comprising an organopolysiloxane containing alkenyl groups, an organopolysiloxane containing hydrogen groups, a thermally conductive filler including aluminum nitride and aluminum oxide, and plasticizers (p. 1, § SUMMARY OF THE PRESENT INVENTION, ll. 25-30; p. 2, ll. 1-3, ll. 27-28). Ding also teaches that the addition of the plasticizer facilitates reducing the viscosity, increasing the fluidity, and reducing the hardness of the composition, and the plasticizer is dimethyl silicone oil (p. 3, ll. 1-2).
Therefore, it would have been obvious to a person of ordinary skill in the art before the effective filing date of the claimed invention to make a thermally conductive composition comprising a matrix resin and thermally conductive particles (aluminum nitride particles, alumina particles and zinc oxide particles) as taught by the combination of Suzumura, Takahashi, Ito and Otsuka, further comprising dimethyl silicone oil as taught by Ding. For doing so, the addition of dimethyl silicone oil would reduce the viscosity, increase the fluidity, and reduce the hardness of the thermally conductive composition for improving the composition’s adhesion between the semiconductor and the heat dissipation unit with a reasonable expectation of success.
Furthermore, it would have been obvious to a person of ordinary skill in the art before the effective filing date of the claimed invention to reasonably expect that the claimed viscosity would flow naturally from the teachings of the combination of Suzumura, Takahashi, Ito, Otsuka and Ding, because the teachings of the combination of references provide substantially the same heat conducting composition comprising the same curable silicone resin, the same thermally conductive powders, and the same dimethyl silicone oil as claimed, and also because the thermally conductive composition of Suzumura has softness to improve the composition’s adhesion between the semiconductor and the heat dissipation unit, and the base polymer in the matrix resin of Suzumura has a viscosity of 0.01 to 1000 Pa·s at 25 °C as recognized by Suzumura, and further because the dimethyl silicone oil of Ding is added to reduce the viscosity, increase the fluidity, and reduce the hardness of the thermally conductive composition as recognized by Ding. Therefore, the invention as a whole would be obvious to a person of ordinary skill in the art.
Regarding claim 3, Suzumura teaches that a thermally conductive composition comprises alumina having an average particle diameter of 6 μm or less (para [0005]), which reads on the claimed metal oxide (B-3) other than zinc oxide.
Regarding claims 5, 6 and 9, Suzumura teaches that the matrix resin component includes organopolysiloxane (component (A1)) and organohydrogenpolysiloxane (component (A2)) (para [0019]), and the alkenyl group in component (A1) and the SiH group in component (A2) are subjected to an addition reaction (hydrosilylation) in a platinum group metal curing catalyst to form a cured product (para [0029], [0033]).
Regarding claim 10, Suzumura teaches that the thermal conductivity of the cured product of the thermally conductive composition is greater than or equal to 12 W/m ·K (para [0010]), which falls within the claimed range of "10.0 W/m·K or more".
Regarding claim 11, as discussed in claim 1 above, based on the total amount of the thermally conductive particles of Suzumura, (a) aluminum nitride with an average particle diameter of 50 μm or more (the claimed aluminum nitride particles (B-1)) can have a content of 34% by mass to 64% by mass, which overlaps with the claimed range of “30 to 42.92% by mass”.
Regarding claim 12, as discussed in claim 1 above, based on the total amount of the thermally conductive particles of Suzumura, (d) aluminum nitride having an average particle diameter of more than 5 μm and less than 50 μm (the claimed aluminum nitride particles (B-2)) can have a content of 13% by mass to 26% by mass, which overlaps with the claimed range of “10 to 17.17% by mass”.
Regarding claim 13, as discussed in claim 1 above, based on the total amount of the thermally conductive particles of Suzumura, (a) aluminum nitride with an average particle diameter of 50 μm or more (the claimed aluminum nitride particles (B-1)) can have a content of 34% by mass to 64% by mass, which overlaps with the claimed range of “30 to 42.92% by mass”; (d) aluminum nitride having an average particle diameter of more than 5 μm and less than 50 μm of Suzumura (the claimed aluminum nitride particles (B-2)) can have a content of 13% by mass to 26% by mass, which overlaps with the claimed range of “10 to 17.17% by mass”.
2. Claim 2 is rejected under 35 U.S.C. 103 as being unpatentable over Suzumura (WO 2020/137086 A1, hereinafter Suzumura) in view of Takahashi (US 5,981,641 A, hereinafter Takahashi), Ito (EP 2194581 A1, hereinafter Ito), Otsuka (JP 2020073621 A, hereinafter Otsuka), and Ding (CN 104098914 B, hereinafter Ding) as applied to claims 1, 3, 5, 6, and 9-13 above, and further in view of Liu (US 2018/0323130 A1, hereinafter Liu).
The disclosure of Suzumura in view of Takahashi, Ito, Otsuka, and Ding is relied upon as set forth above.
Regarding claim 2, Suzumura teaches a thermally conductive composition comprising (d) aluminum nitride having an average particle diameter of more than 5 μm and less than 50 μm (the claimed aluminum nitride particles (B-2)) (para [0015]).
Suzumura does not teach non-sintered broken angular aluminum nitride particles.
However, Liu teaches that a polymer thermal interface material (PTIM) comprises a silicone polymer matrix and non-sinterable particles (para [0061], [0066]), and the non-sinterable particles can be aluminum nitride (para [0067]; claim 7).
Liu also teaches that the microscale non-sinterable fillers have low cost (para [0026]), and the microscale non-sinterable fillers have an average particle size less than 30 micrometers (para [0076]), which overlaps with the range of the aluminum nitride of more than 5 μm and less than 50 μm as taught by Suzumura.
Therefore, it would have been obvious to a person of ordinary skill in the art before the effective filing date of the claimed invention to provide the non-sinterable aluminum nitride having an average particle size less than 30 μm as taught by Liu as the aluminum nitride having an average particle diameter of more than 5 μm and less than 50 μm in Suzumura, in order to lower the cost of the composition. Furthermore, a person of ordinary skill in the art would reasonably expect that the non-sinterable aluminum nitride particles would have irregular shapes, such as broken angular shape. Thus, the invention as a whole would be obvious to a person of ordinary skill in the art.
Response to Arguments
Applicant's arguments with respect to the prior rejections have been considered but are moot, because the arguments do not apply to all of the references being used in the current rejection. The current rejection utilizes a new reference, Otsuka (JP 2020073621 A), in addition to the previous references, Suzumura (WO 2020/137086 A1), Takahashi (US 5,981,641 A), Ito (EP 2194581 A1), and Ding (CN 104098914 B), under a new ground(s) of rejection which renders obvious the instant claims.
Conclusion
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/JIAJIA JANIE CAI/Examiner, Art Unit 1761
/MATTHEW R DIAZ/Primary Examiner, Art Unit 1761