Thinning method of silicon carbide wafer

Abstract

The invention discloses a thinning method of a silicon carbide wafer. The method comprises the steps that the back face of the silicon carbide wafer is divided into the safety ring area and the laserpre-processing area; the laser pre-processing area is a circular area with the area smaller than the area of the silicon carbide wafer back face, and the safety ring area surrounds the edge ring areaof the laser pre-processing area; laser scanning is carried out on the laser pre-processing area, and a laser groove is formed; the position, with the laser groove, of the back face of the silicon carbide wafer is roughly ground until the position is ground to the first target thickness; the silicon carbide wafer back with the first target thickness is subjected to fine grinding until the back face is ground to the second target thickness; and according to the thinning method of the silicon carbide wafer, the fragment problem in the thinning process of the silicon carbide wafer back face is solved, the thinned surface and the subsurface damage of the silicon carbide wafer back face can be improved, the consumable amount of a grinding wheel used during grinding can be reduced, and machiningcost is reduced.

Description

technical field [0001] The invention relates to the field of semiconductor technology, in particular to a method for thinning a silicon carbide wafer. Background technique [0002] Silicon carbide power devices are suitable for extreme working environments such as high temperature, high voltage and high radiation due to their excellent performance. However, silicon carbide devices still generate a lot of heat when working in high-power and extreme environments. By reducing the thermal resistance of the device substrate part, the power loss of the device can be effectively reduced and its heat dissipation can be improved, which plays an important role in the overall performance and life of the device. critical use. [0003] At present, the mainstream technology for preparing large-size ultra-thin silicon carbide in the industry is to use a wafer back thinner to grind and thin the back of the silicon carbide wafer, which can effectively reduce the thermal resistance of the su...

AI Technical Summary

Problems solved by technology

However, since silicon carbide is a hard, brittle and difficult-to-machine material, the wear ratio of the grinding wheel is extremely high

[0004] In addition, as the size of the wafer increases, when the wafer is thinned below a certain thickness, the stress and damage of the silicon carbide wafer are severe, and the wafer is easily broken, resulting in an extremely low yield of wafer thinning

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