Wafer for preparing semiconductor device and back surface thinning method of wafer

Abstract

The invention relates to a wafer for preparing a semiconductor device. The wafer comprises a wafer body, wherein the back surface of the wafer body forms a groove through back surface thinning, the wafer body surrounds the groove to form a supporting ring positioned at the edge of the wafer body, and the side surface of the supporting ring, namely the inner side surface of the groove, is an inclined surface. According to the wafer for preparing the semiconductor device, photoresist is not easy to remain during back surface N-type exposure, so that the influence of the photoresist on equipmentduring annealing is avoided.

Description

technical field [0001] The invention relates to a wafer, in particular to a wafer used for preparing semiconductor devices. In addition, the present invention also designs a wafer backside thinning method. Background technique [0002] When preparing semiconductor devices such as RC-IGBT, it is necessary to perform N-type photolithography on the back of the wafer. Before lithography, the wafer must be thinned to a specified thickness (60um-130um), and the backside lithography equipment has higher requirements on the thickness of the wafer. At present, the backside lithography equipment cannot directly process thinner wafers Therefore, the current prior art uses the TAIKO process to grind the back of the wafer. [0003] The TAIKO process includes the following steps: attach a protective film (blue film or UV film) to the front of the wafer; grind the inside of the wafer (dry etching and wet etching) to a thin sheet (thickness less than 60-130um); remove the protective film;...

AI Technical Summary

Problems solved by technology

When removing the photoresist on the back side, photoresist is easy to accumulate at the right angle formed by the inner side wall of the wafer edge support ring and the inner upper surface of the wafer, resulting in photoresist residue

In the next annealing process, the high temperature will cause the photoresist to volatilize, thereby polluting the furnace tube or blocking the lens of the laser annealing equipment, thereby affecting the activation efficiency of impurities and reducing the product yield

At the same time, the wafers ground by the TAIKO process have high stress, which is easy to cause photolithographic alignment and affect device performance.

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