Lead frame with improved adhesiveness property against plastic and plastic sealing type semiconductor packaging using said lead frame

A semiconductor package including:

• a semiconductor element;
• a lead frame having said semiconductor element mounted thereon, said lead frame being electrically connected to said semiconductor element;
• and a sealing plastic for gas-tight sealing said semiconductor element and a part of said lead frame,
• said lead frame comprising:
• a matrix for said lead frame consisting essentially of a copper based alloy containing dispersive particles, a part of said dispersive particles being distributed on the surface of said matrix, a content of P in said copper based alloy being 30 ppm or less;
• and
• an oxide layer formed at least at a part on the matrix where said matrix contacts with said sealing plastic, said oxide layer containing an oxide of said dispersive particles distributed on the surface of said matrix.

A semiconductor package including:

• a semiconductor element;
• a lead frame having said semiconductor element mounted thereon, said lead frame being electrically connected to said semiconductor element;
• and a sealing plastic for gas-tight sealing said semiconductor element and a part of said lead frame,
• said lead frame comprising:
• a matrix for said lead frame consisting essentially of a copper based alloy containing dispersive particles with a size of 0.1 .mu.m to 50 .mu.m, said dispersive particles being present on the surface of said matrix within a range of 100 to 100000 pieces/mm.sup.2 ;
• and
• an oxide layer formed at a part where said matrix contacts with said sealing plastic, said oxide layer containing an oxide of said dispersive particles distributed on the surface of said matrix.