Method for improving warpage of sheet

Abstract

The invention provides a method for improving wafer warping. The method comprises the following steps: providing a wafer; forming a first film layer with first tensile stress on the outer surface of the front surface of the wafer; a second film layer with second tensile stress is formed on the outer surface of the reverse side of the wafer, and the direction of the second tensile stress is opposite to that of the first tensile stress, so that the second tensile stress counteracts the first tensile stress. According to the invention, the tensile stress of the back film layer of the wafer is increased, the tensile stress of the front film layer of the wafer is partially counteracted, and the overall stress of the wafer is reduced, so that the wafer does not warp, and subsequent processing is not influenced.

Description

technical field [0001] The invention relates to the technical field of semiconductors, in particular to a method for improving thin slice warpage. Background technique [0002] During the production of power device products in the fab, due to the thicker film thickness and higher process temperature, higher stress is generated in the device manufacturing process. These high-stress wafers will become severely warped after the thinning process, causing a series of problems such as machine alarms and high wafer fragmentation rates. In severe cases, it may even affect the processing of thin wafers. [0003] Power metal-oxide transistors based on superjunction technology have become the industry norm in the field of high-voltage switching converters. They offer lower quiescent on-state resistance with less gate and output charge, which helps maintain higher efficiency at any given frequency. Due to the influence of polyimide (PI) layer stress on some super junction (SJ) product...

AI Technical Summary

Problems solved by technology

Due to the influence of polyimide (PI) layer stress on some super junction (SJ) products, the warpage is too large during sheet processing, which affects the quality of super junction (SJ) products with polyimide (PI) layer. Circulation during rate testing

[0004] In the prior art, usually by finding the stress level that causes warping, optimizing the operation of the stress layer and changing the stress of the metal film layer by adjusting the process temperature, the production efficiency is low and the improvement effect is relatively limited.

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