Bump forming process
OwnerHo-Ming Tong, Chun-Chi Lee +6inventors
InventorsHo-Ming Tong, Chun-Chi Lee, Jen-Kuang Fang, Min-Lung Huang, Jau-Shoung Chen, Ching-Huei Su, Chao-Fu Weng, Yung-Chi Lee
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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.
Claims34
A process for forming a plurality of bumps on a wafer, comprising:
- forming a first UBM (under ball metallurgy) over an active surface of the wafer;
- forming a second UBM over the first UBM;
- performing a photolithography process to form a plurality of patterns on the second UBM;
- performing a first etching process to remove a portion of the second UBM not covered by the patterns;
- removing the patterns;
- performing a second photolithography process to form a photoresist layer over the adhesive layer, wherein the photoresist layer has a plurality of openings respectively exposing portions of the second UBM and the first UBM not covered by the second UBM;
- forming a plurality of solders respectively into the openings of the photoresist layer to cover the portions of the second UBM and first UBM not covered by the second UBM;
- removing the photoresist layer;
- and
- performing a second etching process to remove the portions of the first UBM respectively not covered by the second UBM and the solders.
The process of claim 15, wherein an etchant used to etch the barrier layer in the first etching step includes a diluted phosphoric acid.
A process for forming a plurality of bumps on a wafer, the process comprising:
- 1) forming a first UBM (under ball metallurgy) over an active surface of the wafer;
- 2) forming a second UBM over the first UBM;
- 3) removing a portion of the second UBM to expose the first UBM;
- 4) forming a plurality of solders correspondingly on the second UBM and a portion of the first UBM not covered by the second UBM;
- and
- 5) removing the portion of the first UBM respectively not covered by the second UBM and the solders.
Dependencies are inferred from the claim text.