Aluminum cushion layer etching method and bump formation method

Abstract

A method for etching an aluminum pad layer comprises providing a semiconductor substrate, forming an aluminum pad layer, a passivating layer and a dielectric layer on the semiconductor substrate, wherein the aluminum layer is inlaid in the passivating layer and exposes through the passivating layer and a first opening of the dielectric layer, and further utilizing argon plasma to etch the aluminum pad layer, wherein the production power (MF) for generating the argon plasma is arranged between 600W and 800W, the accelerating power (RF) for accelerating the argon plasma is arranged between 100W and 600W, and the etching time is arranged between 55s and 100s. The invention further provides a method for forming bumps. Compared with the prior art, the method for etching an aluminum pad layer reduces the generation power (MF) for generating the argon plasma, the accelerating power (RF) for accelerating the argon plasma and the time to etch the aluminum pad layer, thereby avoiding the problem of rough surface of the aluminum pad layer caused by over-etching to the aluminum pad layer in the prior art.

Description

technical field [0001] The invention relates to the technical field of semiconductor manufacturing, in particular to a method for etching an aluminum pad layer and a method for forming bumps. Background technique [0002] In the back-end process of semiconductor integrated circuits, the last patterned aluminum layer forms an array of aluminum pads to provide connections for input / output (I / O) or power / ground signals; then a passivation layer is deposited on the aluminum pads and a first dielectric layer, the passivation layer is, for example, polyimide, and the first dielectric layer is, for example, benzenepropane (BCB); then a first dielectric layer is formed in the passivation layer and the first dielectric layer The opening exposes the aluminum pad layer; then a rewiring layer is formed in the first opening; then a second dielectric layer is formed on the rewiring layer, and the second dielectric layer is a relatively thick polymer (usually polyimide or phenylpropane) t...

AI Technical Summary

Problems solved by technology

However, after research, it was found that after the aluminum pad layer was etched using the existing technology, the surface of the rewiring layer formed on the aluminum pad layer was very rough, which would easily cause leakage current or increase the contact resistance, thereby affecting the yield of shipment inspection.

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