Method of joining chips utilizing copper pillar

A method for fabricating a chip package, comprising:nproviding a copper pillar on a chip and a first tin-containing layer over said copper pillar, wherein said first tin-containing layer has a thickness less than a thickness of said copper pillar;providing a second tin-containing layer on a substrate, wherein said second tin-containing layer has a thickness less than said thickness of said copper pillar; andafter said providing said copper pillar on said chip and said first tin-containing layer over said copper pillar and said providing said second tin-containing layer on said substrate, joining said chip with said substrate, wherein said joining said chip with said substrate comprises joining said first tin-containing layer with said second tin-containing layer, wherein said first tin-containing layer contacts said second tin-containing layer, wherein said chip remains joined with said substrate.

A method for fabricating a chip package, comprising:nproviding a copper pillar on a chip and a tin-containing layer over said copper pillar, wherein said tin-containing layer has a thickness less than a thickness of said copper pillar;providing a gold-containing layer on a substrate, wherein said gold-containing layer has a thickness less than said thickness of said copper pillar; andafter said providing said copper pillar on said chip and said tin-containing layer over said copper pillar and said providing said gold-containing layer on said substrate, joining said chip with said substrate, wherein said joining said chip with said substrate comprises joining said tin-containing layer with said gold-containing layer, wherein said tin-containing layer contacts said gold-containing layer, wherein said chip remains joined with said substrate.

A method for fabricating a chip package, comprising:nproviding a metal bump on a chip, wherein said metal bump comprises a copper pillar over said chip;providing a tin-containing layer on a substrate, wherein said tin-containing layer has a thickness greater than 15 micrometers and less than a thickness of said copper pillar; andafter said providing said metal bump on said chip and said providing said tin-containing layer on said substrate, joining said chip with said substrate, wherein said joining said chip with said substrate comprises joining said metal bump with said tin-containing layer using a process comprising a reflow process, wherein said metal bump contacts said tin-containing layer, wherein said chip remains joined with said substrate.

A method for fabricating a chip package, comprising:nproviding a copper pillar on a chip and a first gold-containing layer over said copper pillar, wherein said first gold-containing layer has a thickness less than a thickness of said copper pillar;providing a second gold-containing layer on a substrate, wherein said second gold-containing layer has a thickness less than said thickness of said copper pillar; andafter said providing said copper pillar on said chip and said first gold-containing layer over said copper pillar and said providing said second gold-containing layer on said substrate, joining said chip with said substrate, wherein said joining said chip with said substrate comprises joining said first gold-containing layer with said second gold-containing layer, wherein said first gold-containing layer contacts said second gold-containing layer, wherein said chip remains joined with said substrate.

A method for fabricating a multi-chip structure, comprising:nproviding a copper layer on a first chip and a first tin-containing layer over said copper layer;providing a second tin-containing layer on a second chip; andafter said providing said copper layer on said first chip and said first tin-containing layer over said copper layer and said providing said second tin-containing layer on said second chip, joining said first chip with said second chip, wherein said joining said first chip with said second chip comprises joining said first tin-containing layer with said second tin-containing layer, wherein said first tin-containing layer contacts said second tin-containing layer, wherein said first chip remains joined with said second chip.