Study on working solution of laser-induced backside wet etching

In order to process sapphire with high efficiency and high quality by using low cost infrared fiber laser, laser-induced backside wet etching (LIBWE) was used. Theoretical analysis and experimental verification were carried out. New type of the mixed solution with high activity and stability was developed in which mass concentration of copper sulfate, sodium hypophosphite, ammonia was 28g/L, 40g/L, 45g/L respectively and whose pH value was 12. Under the same processing conditions, sapphire was cut in copper sulfate solution and the mixed solution. The results show that the cutting efficiency of sapphire in the mixed solution is about 5 times higher than that in copper sulfate solution. High-quality special-shaped sapphire parts have been processed with the mixed solution. This research has certain guiding significance for improving the processing efficiency of sapphire under the action of low power laser.