Classification method for sapphire substrate slices

Abstract

The invention provides a classification method for sapphire substrate slices. The sapphire substrate slices are sorted firstly according to the Warp value, wherein the substrate slices with the Warp smaller than 16 micrometers are directly subjected to straight-line type boron carbide two-sided lapping; after the substrate slices with the Warp larger than or equal to 16 micrometers and smaller than 25 micrometers are subjected to 1,400-DEG C high-temperature annealing for 12 H, straight-line type boron carbide two-sided lapping is conducted; after the substrate slices with the Warp larger than or equal to 25 micrometers and smaller than 35 micrometers are subjected to 1,400-DEG C high-temperature annealing for 12 H, and circulating type boron carbide twos-sided lapping is conducted; and in this way, by the adoption of the classification management method, the problems that the circulating type boron carbide two-sided lapping is directly selected, and consequently the efficiency is lowered fast, the later lapping time length is increased remarkably, and the lapping cost is increased can be avoided effectively, the problems that when the straight-line type boron carbide two-sided lapping is adopted, the warp value of the lapped substrate slices with the warp value larger than or equal to 25 micrometers is larger, and consequently the secondary rework even scrap are caused are avoided effectively as well, the yield is increased, and the cost is saved.

Description

technical field [0001] The invention relates to the technical field of sapphire crystal manufacturing, in particular to a method for classifying sapphire substrate slices after being sliced. Background technique [0002] Sapphire (A-alumina) crystal material is a colorless and transparent single crystal material with a series of excellent comprehensive physical and chemical properties such as high strength, high hardness (Mohs scale 9), high temperature resistance, and good chemical stability. It is widely used in high brightness LED substrate material. [0003] When the sapphire substrate transitions from 2 inches to 4 inches, the simple stress difference between the polishing surface and the grinding surface cannot control the bending of the sapphire substrate to the polishing surface, and the substrate surface shape will follow the wafer in the SagX and SagY directions The degree of warp (Warp) presents different Bow values. The current 4-inch sapphire substrate slices ...

AI Technical Summary

Problems solved by technology

The current 4-inch sapphire substrate slices are managed in batches of ingots after being sliced, and there are two processing methods for the subsequent grinding process: one is to circulate the entire batch of 4-inch sapphire substrate slices after slicing. Surface grinding, this method has the following disadvantages: Circular grinding is accompanied by an increase in the number of cycles, its grinding efficiency drops rapidly, and the length of subsequent grinding increases significantly; due to the increase in grinding time, a large increase in grinding equipment and operators is required. The processing cost is reduced; one is to carry out in-line boron carbide double-sided grinding on the entire batch of 4-inch sapphire substrates after slicing. This method has the following defects: some sapphire substrates with Warp values ​​≥ 25 are Warp after grinding. The value is too large, resulting in secondary rework or even scrapping