The Characterization of Electroless Ni Bump for the Flip Chip

摘要

In the present work, the flip chip bumping process by electroless Ni for UBM was investigated. The chip used in this experiment has an array of pad 14 x 14 and the pad's size is 100 x 100 μm. Through the result of zincates as pretreatment of Al, it was shown that the second zincating process produced a dense continuous zincating layer compared to first zincating. The deposited Ni bump was identified by XRD as amorphous structure composed of Ni-P (about 12wt% Phosphorous) and crystallized at 594K to Ni and Ni_3P.