| 摘要 |
A bumping process includes the steps of: firstly, providing a wafer; forming a first photo-resist layer on a active surface of the wafer and forming at least a first opening on the first photo-resist layer; next, forming a first copper pillar in the first opening; next, forming a second photo-resist layer on the first photo-resist layer and forming at least a second opening on the second photo-resist layer, wherein the second opening smaller than the first opening so that a portion of the surface of the first copper pillar is exposed in the second opening; then, forming a second copper pillar in the second opening; finally, forming a solder layer on the second copper pillar; and removing the first and second photo-resist layers. |
