| 摘要 |
PROBLEM TO BE SOLVED: To improve a heat sink in thermal conductivity as a whole by a method, wherein all the one surface of a metal board of comparatively satisfactory thermal conductivity is covered with a polycrystalline diamond layer of a specified thickness. SOLUTION: A semiconductor element 5, bonding wires 7 connected to the semiconductor element 5, and a lead frame 6 connected to the bonding wires 7 are provided inside a package 1. A metal board material 2, a polycrystalline diamond layer 3, a first intermediate bonding layer 8a, a second intermediate bonding layer 8b, and a metal bonding layer 4 are provided in this order starting from the bottom to serve as a base for the semiconductor element 5. At this point, a Cu-W sintered body (Cu 10%) board (metal board material 2) 15×15 mm with 0.6 mm thickness is subjected to cleaning for degreasing, pickling, and a pre-treatment where granular diamond is used, and a polycrystalline diamond layer 3 is formed in 40 μm thickness on the metal board material 2 through a hot filament CVD metal. The CVD method is carried out under the conditions, where the material gas is composed of hydrogen of 1,000 sccm and methane of 20 sccm, gas pressure is set at 60 Torr, W filament temperature is set at 2,000 to 2,100 deg.C, and the time is set at 40 hours. |
