Patent ID: 9655237
Date: 2017-05-16
CPC Classifications: B32B,C04B,H01L,H05K,Y10T

Claim:
1. A silicon nitride substrate which is a sintered body comprising a main phase comprised of silicon nitride particles, and an intergranular phase comprised of a sintering aid, wherein the main phase contains, on the substrate surface, first silicon nitride particles having an aspect ratio obtained by dividing a major axis length by a minor axis length of 3.0 or less, and having a major axis length of 5.0 μm or less, and second silicon nitride particles having a major axis length and an aspect ratio both exceeding those of the first silicon nitride particles, 40 or less first silicon nitride particles are present within a 10 μm square region set on any selected parts on the substrate surface, a ratio (B/Si) between fluorescent X-ray intensities of boron (B) and silicon (Si) on any selected parts on the substrate surface is in range of 7.0×10 the ratio B/C between boron (B) and carbon (C) is 0.080 to 3.000, the surface waviness is 1.00 μm or less, the surface waviness being an arithmetic average waviness Wa, which is an arithmetic average of absolute values of deviation from an average value of a surface height, obtained by measuring a filtered centerline waviness using a surface roughness meter, and the thickness t is 0.20 to 0.80 mm, with the proviso that, for the substrate surface waviness, the measurement conditions include an evaluation length of 30 mm, a measurement velocity of 0.3 mm/s, a cut-off value (λc) of 0.25 mm, and a cut-off value (λf) of 8.0 mm.