Method of fabricating a semiconductor structure having conductive bumps with a plurality of metal layers

摘要

A conductive bump structure used to be formed on a substrate having a plurality of bonding pads. The conductive bump structure includes a first metal layer formed on the bonding pads, a second metal layer formed on the first metal layer, and a third metal layer formed on the second metal layer. The second metal layer has a second melting point higher than a third melting point of the third metal layer. Therefore, a thermal compression bonding process is allowed to be performed to the third metal layer first so as to bond the substrate to another substrate, and then a reflow process can be performed to melt the second metal layer and the third metal layer into each other so as to form an alloy portion, thus avoiding cracking of the substrate.

主权项

1. A method of fabricating a semiconductor structure, comprising:
providing a carrier and a substrate having a plurality of bonding pads and a plurality of conductive bumps formed respectively on the bonding pads, wherein each of the conductive bumps has a first metal layer formed on a corresponding one of the bonding pads, a second metal layer formed on the first metal layer, and a third metal layer formed on the second metal layer, and the second metal layer has a second melting point higher than a third melting point of the third metal layer; heating the substrate and the carrier to a first temperature range, so as for the third metal layer to be melted and thereby bonded with the carrier; and heating the substrate and the carrier to a second temperature range, so as for the second metal layer to be melted to form an alloy portion with the third metal layer, and the first metal layer and the alloy portion to form a conductor for electrically connecting the carrier and the substrate.