| 摘要 |
PURPOSE:To enhance matching of a thermal expansion coefficient and heat dissipation by integrally pressing a low thermal expansion metal board having a large number of through holes in a thickness direction on at least one main surface of a copper or copper alloy board and by partially exposing copper or copper alloy on a low thermal expansion metal board surface from through holes. CONSTITUTION:After a large number of through holes 13 in the direction of board thickness are punched on required positions of a low thermal expansion metal board 11, the low thermal expansion metal board 11 and a copper or copper alloy board 12 are cold-pressed, and the surface of the copper or copper alloy board 12 is partially exposed on a required position of one main surface low thermal expansion metal board 11. Thus, a lead frame 10 can be given a good conductivity. Any value of a low thermal expansion coefficient between that of a copper, copper alloy, or a low thermal expansion metal material can be chosen at the volume ratio of the copper or copper alloy to the low thermal expansion metal material. Thus, the matching of a low thermal expansion coefficient with sealing resin can be obtained together with semiconductor chips. |
