Patent ID: 9548282
Date: 2017-01-17
CPC Classifications: H01L

Claim:
1. A method for forming a semiconductor device, comprising: providing a semiconductor substrate with a pad formed therein; forming a passivation layer on the semiconductor substrate, the passivation layer having a first opening which exposes a surface of the pad; forming a columnar electrode above the pad, wherein the columnar electrode comprises a main body and at least one groove in the main body, and an opening of the at least one groove is overlapped with a top surface of the columnar electrode; and forming a solder ball on the columnar electrode, the solder ball comprising a metal bump formed on the top surface of the columnar electrode and a filling part filled in the at least one groove, wherein forming the at least one columnar electrode above the pad comprises: removing the first photoresist layer; removing a portion of the seed layer on the passivation layer with the main body as a mask; forming a first insulating layer on the passivation layer; forming a second photoresist layer on the first insulating layer and on the main body of the columnar electrode, wherein the second photoresist layer has at least one third opening which exposes a top surface of the main body of the columnar electrode; and removing a portion of the main body of the columnar electrode by etching along the at least one third opening, to form the at least one groove in the main body, wherein the main body and the at least one groove in the main body constitute the columnar electrode, wherein a top surface of the first insulating layer is flush with the top surface of the main body, and the first insulating layer contacts with a sidewall of the columnar electrode, and wherein forming a solder ball on the columnar electrode removing the second photoresist layer comprises: