| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a silicon nitride ceramic circuit board capable of effectively suppressing a leak current when a silicon nitride ceramic substrate is used to constitute various power modules, and capable of improving insulating property and operative reliability even in power modules with greatly increased power and capacity. <P>SOLUTION: This invention provides the silicon nitride ceramic circuit board 1 composed of a silicon nitride sintered body in which porosity is 2.5% or less in capacity ratio and maximum size of pore existing in grain boundary phase is 0.3 μm or less. A plurality of metal circuit plates 3, 3 are provided on the silicon nitride ceramic substrate 2 having a thermal conductivity of 50 W/mK or more and a three point bending strength of 500 MPa or more, wherein a leak current value is 1,000 nA or less when an alternating voltage of 1.5 kV-100 Hz is applied to a portion between front and back surfaces of the silicon nitride sintered body under conditions of a temperature of 25°C and a humidity of 70%. An interval of the metal circuit plates 3, 3 is in a range of 0.1-2.0 mm. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
