Bump fabrication method
AssigneeAdvanced Semiconductor Engineering, Inc.
InventorChao-Fu Weng
Life of this patent
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Abstract
A method of fabricating bumps is disclosed. In the present method, prior to forming solder, layer pattern, the wetting layer and the barrier layer are removed, and after a solder layer pattern is formed, only the exposed adhesion layer is removed. The method can avoide etching the solder layer pattern in the course of etching the solder layer and the barrier layer, and therefore the volume of the required solder layer pattern can be maintained. Thus, the height of the bump after the re-flow process is maintained at an appropriate range and the required bonding force between the bump and the under ball metallurgy layer pattern can be maintained so as to improve the reliability.
Claims13
A method of fabricating bumps comprising the steps of:
- providing a wafer having a plurality of bump pads and a passivation layer on the surface of the wafer and exposing the bump pads;
- forming an adhesion layer, a barrier layer and a wetting layer in sequence on the surface of the wafer;
- defining the wetting layer and the barrier layer to form a plurality of Under Bump Metallurgy (UBM) patterns exposing the adhesion layer, wherein the UBM patterns correspond to each of the bump pads;
- then,
- forming a plurality of solder layer patterns on the surface of the UBM patterns, wherein each of the solder layer patterns corresponds to each of the UBM patterns;
- then,
- removing the exposed adhesion layer after forming the plurality of solder layer patterns;
- and
- performing a reflow process to form a plurality of bumps transformed from the solder layer patterns after the exposed adhesion layer is removed.
Dependencies are inferred from the claim text.