| 摘要 |
PROBLEM TO BE SOLVED: To obtain a sintered compact excellent in mechanical strength and having a high heat conductivity without anisotropy in the direction of heat conduction by including silicon nitride as a principal component, including aluminum and oxygen in specific values or below of contents as impurities and respectively regulating the heat conductivity and four-point bending strength at normal temperatures to specified values or above. SOLUTION: This silicon nitride-based sintered compact is obtained by regulating the content of aluminum as an impurity element therein to <=0.2 wt.% and the content of oxygen as an impurity element therein to <=3.0 wt.% and further regulating the heat conductivity to >=70 W/(m.K) and the four-point bending strength to >=600 Pa. The amount of carbon in the sintered compact is preferably <=2.0 wt.% and the total amount of magnesium and a group 3a element of the periodic table contained therein is preferably 0.6-4.0 wt.% The weight ratio (MgO/RExOy) thereof is preferably 1-70. The ratio of β-type silicon nitride grains having >=5 μm minor axis diameter in the sintered compact is preferably <=10 vol.%. When the sintered compact is used as a substrate for a semiconductor element, the thermal shock resistance and heat cycle resistance are improved to thereby provide a substrate material excellent in durability and reliability. |
