JPWO2022210518A5 - - Google Patents

Claims (7)

An aluminum nitride sintered body containing aluminum nitride particles and sintering aid particles,
A laminate was prepared by laminating with a metal plate, exposed to an environment of 350 ° C. for 5 minutes, cooled for 5 minutes in an environment of 25 ° C., and exposed to an environment of -78 ° C. for 5 minutes. , an aluminum nitride sintered body having an observed crack rate of less than 9.00 area % when subjected to a heat cycle test of 10 cycles, one cycle of which is an operation of returning to 25°C. 2. The aluminum nitride sintered body according to claim 1, which has a plate-like shape having a pair of main surfaces, and the difference between the maximum height roughness Ry and the arithmetic mean roughness Ra on the main surfaces is 6.0 μm or less. 3. The aluminum nitride sintered body according to claim 2, wherein said maximum height roughness Ry is less than 10.0 [mu]m. In the cumulative frequency distribution curve of the particle size measured by electron microscope image analysis for the aluminum nitride particles, the particle size when the integrated value from the small particle size reaches 50% and 90% of the total is d50 and d90, respectively. 4. The aluminum nitride sintered body according to any one of claims 1 to 3, wherein the value of d90-d50 is less than 10.0 µm. A circuit board comprising the aluminum nitride sintered body according to any one of claims 1 to 4 and a conductor portion attached to the aluminum nitride sintered body. A laminated substrate comprising the aluminum nitride sintered body according to any one of claims 1 to 4 and a metal plate attached to the aluminum nitride sintered body. a firing step of firing a molded body composed of a mixture containing aluminum nitride and a sintering aid for 1 to 6 hours to obtain a sintered body;
obtaining an annealed product by heat-treating the sintered body at a temperature of 1400° C. or more and less than 1700° C. for 1 hour or more;
and obtaining an aluminum nitride sintered body by polishing the surface of the annealed product,
The sintering aid contains yttrium oxide and aluminum oxide,
The mass ratio of the aluminum oxide to the yttrium oxide is less than 0.5,
The firing step includes
a step of obtaining a first fired body from the molded body by heating at a temperature of 1700° C. or more and less than 1800° C. for 1 hour or more;
and obtaining the sintered body from the first sintered body by heating at a temperature of 1800 to 1900° C. for 1 hour or more.