METHOD AND STRUCTURE FOR ADHESION OF INTERMETALLIC COMPOUND ON COPPER PILLAR BUMP

摘要

PPROBLEM TO BE SOLVED: To provide a method and structure for good adhesion of intermetallic compounds (IMC) on copper pillar bumps. PSOLUTION: The method includes depositing copper to form a copper pillar layer 108, depositing a diffusion barrier layer 110 on a top of the copper pillar layer, and depositing a copper cap layer 112 on top of the diffusion barrier layer, wherein an intermetallic compound (IMC) 116 is formed among the diffusion barrier layer, the copper cap layer, and a solder layer formed on a top of the copper cap layer. The IMC has good adhesion on the copper pillar structure, the thickness of the IMC is controllable by the thickness of the copper cap layer, and the diffusion barrier layer limits diffusion of copper from the copper pillar layer to the solder layer. The method can further include depositing a thin layer for wettability on top of the diffusion barrier layer prior to depositing the copper cap layer. PCOPYRIGHT: (C)2011,JPO&INPIT