Insulation circuit board with heat sink

Abstract

An insulated circuit board which is obtained by bonding a circuit layer onto one side of a ceramic substrate, and bonding a metal layer made of copper or copper alloy onto the other side of the ceramic substrate; and a heat sink which is bonded to the metal layer are included; the heat sink has a first metal layer made of aluminum or aluminum alloy joined to the metal layer, a ceramic board material joined to the first metal layer at an opposite side to the metal layer, and a second metal layer made of aluminum or aluminum alloy joined to the ceramic board material at an opposite side to the first metal layer; a thickness T1 of the first metal layer and a thickness T2 of the second metal layer are 0.8 mm to 3.0 mm inclusive; and a thickness ratio T1/T2 is 1.0 or more.

1 . (canceled) 
     
     
         2 . (canceled) 
     
     
         3 . (canceled) 
     
     
         4 . An insulation circuit board with a heat sink comprising an insulation circuit board provided with a ceramic substrate, a circuit layer bonded on one side of the ceramic substrate, and a metal layer made of copper or copper alloy bonded on the other side of the ceramic substrate; and a heat sink bonded on the metal layer, wherein
 the heat sink has a first metal layer bonded on the metal layer, made of aluminum or aluminum alloy with a thickness T1, a ceramic board material bonded on the first metal layer at an opposite side to the metal layer, and a second metal layer with a thickness T2 made of aluminum or aluminum alloy bonded on the ceramic board material at an opposite side to the first metal layer; and   wherein 0.2≤T1≤0.5 (mm), 0.3≤T2≤0.6 (mm), and a thickness ratio T1/T2<1.0.   
     
     
         5 . The insulation circuit board with a heat sink according to  claim 4 , wherein
 the circuit layer is made of copper or copper alloy, and   the ceramic substrate and the ceramic board material are made of silicon nitride.   
     
     
         6 . The insulation circuit board with a heat sink according to  claim 4 , wherein the metal layer and the first metal layer are solid phase diffusion bonded. 
     
     
         7 . The insulation circuit board with a heat sink according to  claim 5 , wherein the metal layer and the first metal layer are solid phase diffusion bonded.