Patent ID: 8168555

Claim:
A ceramic substrate having a main composition comprising Mg 2 SiO 4 and a low-temperature-fired component and having a coefficient of thermal expansion α of not less than 9.0 ppm/° C., said ceramic substrate comprising up to 25 vol. % (excluding zero) ZnAl 2 O 4 , wherein the main composition comprises Mg 2 SiO 4 as a major component and the low-temperature-fired component comprises ZnO, B 2 O 3 , CuO, and RO (where R designates an alkaline earth metal), and wherein, where a is a mass of said Mg 2 SiO 4 , b a mass of ZnO, c a mass of B 2 O 3 , d a mass of CuO, and e a mass of RO, relative to a total mass (a+b+c+d+e), a proportion of the mass b of ZnO, b/(a+b+c+d+e), is in the range of 8% to 20%, a proportion of the mass c of B 2 O 3 , c/(a+b+c+d+e), is in the range of 3% to 10%, a proportion of the mass d of CuO, d/(a+b+c+d+e), is in the range of 2% to 8%, and a proportion of the mass e of RO, e/(a+b+c+d+e), is in the range of 1% to 4%.