| abstract |
A process for forming a plurality of bumps on a wafer comprises forming a first UBM (under ball metallurgy) over an active surface of a wafer. A second UBM is formed over the first UBM. A part of the second UBM is removed to expose the first UBM. A plurality of solders are respectively formed to cover the second UBM and the first UBM not covered by the second UBM. The first UBM not covered by the second UBM and not covered by the solders is removed. |