SEMICONDUCTOR PACKAGE HAVING IMPROVED ADHESION AND SOLDERABILITY

摘要

A leadframe with a base metal structure (for example, copper) and first and second surfaces. A first metal layer, which is adhesive to polymeric materials such as molding compounds, is adherent to the first leadframe surface. The second leadframe surface is covered by a second metal layer for affinity to reflow metals such as tin alloy; this second metal layer has a different composition from the first metal layer. One example of the first surface is a nickel layer (201) in contact with the base metal (105), a palladium layer (202) in contact with the nickel layer, and an outermost tin layer (203) in contact with the palladium. Another example is an oxidized surface of the base metal. The second metal layer, on the second leadframe surface, comprises a nickel layer (201) in contact with the base metal (105), a palladium layer (202) in contact with the nickel layer, and an outermost gold layer (204) in contact with the palladium layer.