TSV wafer surface polishing method

Abstract

The invention provides a TSV wafer surface polishing method. Firstly, a copper layer on the surface of a TSV blind hole electroplated wafer is corroded through a H2SO4 solution and a hydrogen peroxide mixed solution; then, the wafer adheres to a ceramic plate through thermal spalling double-faced adhesive tape for the wafer sample preparation process; the whole wafer is placed on a rotary plate attached to a polishing pad for polishing and copper layer removal; finally, after the ceramic plate is heated and taken off, Ta or Ti corrosive liquid is adopted, a Ta or Ti blocking layer corresponding to the surface of the TSV blind hole electroplated wafer is removed, and polishing of the surface of the TSV wafer is finished. By adding micro-processing of the surface of the TSV blind hole electroplated wafer, the state of the surface of the blind hole electroplated wafer is improved, polishing of the copper layer is facilitated, and polishing cost is reduced. Process operation is simple, cost is low, and the method is suitable for wafers and fragments of different sizes. By means of the thermal spalling double-faced adhesive tape, thickness uniformity in the wafer sample preparation process can be improved, and quality of the surface of the polished TSV blind hole electroplated wafer is improved.

Description

technical field [0001] The invention relates to a process method for semiconductor processing, in particular to a method for polishing the surface of a TSV wafer. Background technique [0002] In the Through Silicon Via technology (TSV; Through Silicon Via) process, after a through hole is formed on the wafer, metal Cu is generally plated in the through hole to form a vertical electrical interconnection. After the wafer is electroplated, there will be a certain thickness of Cu layer on the wafer surface. Controlled by the size of the through hole and the electroplating time, the thickness of the Cu layer on the wafer surface is ten to tens of microns. The Cu layer on the wafer surface needs to be removed in order to perform subsequent processes on the wafer surface, such as gluing, photolithography, and the like. The removal effect of the thicker Cu layer will directly affect the subsequent process quality of the wafer surface. [0003] At present, the Cu layer on the wafe...

AI Technical Summary

Problems solved by technology

That is, a polishing pad is attached to the circular rotating disk, and the vacuum disk is used to absorb the back of the wafer and press it on the polishing pad to give a certain pressure on the back of the wafer. Use the metal Cu polishing solution to infiltrate the polishing pad, and rotate the vacuum disk and the rotating disk at the same time. The purpose of removing the Cu layer is achieved, but its quality cannot be guaranteed to be stable and uniform

The chemical mechanical polishing machine is expensive, and the Cu layer formed in the TSV process is thick, which requires a long polishing time, and the cost of this method is high; and the chemical mechanical polishing machine can only polish a large-sized wafer, and the adaptability is relatively small. Difference

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