Methods of forming semiconductor packages with an intermetallic layer comprising tin and at least one of silver, copper or nickel

A method of forming a semiconductor package, comprising:

• forming an intermediate metal layer onto a die backside, the intermediate metal layer comprising a plurality of sublayers coupled to each other, each sublayer comprising a metal selected from the group consisting of titanium, nickel, copper, silver, and any combination thereof;
• depositing a tin layer onto the intermediate metal layer;
• and
• reflowing at least a portion of the intermediate layer and the tin layer with a silver layer of a substrate to form an intermetallic layer having a melting temperature greater than 260 degrees Celsius;
• wherein the plurality of sublayers of the intermediate metal layer includes a sublayer comprising copper, a sublayer comprising titanium, and a sublayer comprising nickel.

A method of forming a semiconductor package, comprising:

• forming an intermediate metal layer onto a die backside, the intermediate metal layer comprising a plurality of sublayers coupled to each other, each sublayer comprising a metal selected from the group consisting of titanium, nickel, copper, silver, and any combination thereof;
• depositing a tin layer onto the intermediate metal layer;
• and
• reflowing at least a portion of the intermediate layer and the tin layer with a silver layer of a substrate to form an intermetallic layer having a melting temperature greater than 260 degrees Celsius;
• wherein the plurality of sublayers of the intermediate metal layer includes a sublayer comprising titanium and a sublayer comprising copper.