| 摘要 |
PURPOSE:To provide a semiconductor device which comprises a material consisting of copper or copper alloy where the substantial thermal expansion coefficient of copper material is approximated to that of semiconductor pellet and can be directly bonded to the copper material without generating any crack and distortion on the pellet even in case a large size semiconductor pellet is used. CONSTITUTION:A thermal expansion coefficient alpha of copper material surface on a substrate 20 where a copper foil is strongly adhered to a ceramic plate is measured as about 11X10<-6> deg.C<-1>. A thermal contraction difference at the temperature difference of 250 deg.C between the copper on the substrate having such thermal expansion coefficient and a silicon pellet of 15mm. square is measured as about 14mum. Accordingly, any crack is not generated even in the actual die bonding and a semiconductor device does not show any abnormal phenomenon in the characteristic even in the successive temperature cycle test (-55-150 deg.C). Fall of thermal expansion coefficient of copper on the substrate is primarily determined by the thickness of copper sheet and ceramic plate. Such fall is almost not changed depending on the kind of eutectic and only the criterion is different in accordance with a kind of copper, copper alloy and ceramic. |
