A Cleaning Process Instead of Sapphire Substrate Wafer Pickling

Abstract

The invention discloses a washing process substituting sapphire substrate wafer acid pickling. The washing process includes the steps that large particles on the surface are scrubbed down firstly, a wafer is then socked into an emulsifier so that the adsorption state of the surface of the wafer can be controlled, dirt on the surface of the wafer is removed through a washing agent, organic matter and metal ions on the surface of the wafer are further washed away through ozone water containing a catalyst, then the catalyst is removed through the washing agent, the wafer is finally placed in isopropyl alcohol so that submicron particles on the surface of the wafer can be removed, the metal ion content of the surface is reduced, water mark defects are avoided, meanwhile, static electricity generated in a traditional heating drying process is avoided, and it is guaranteed that the surface of the wafer cannot be secondarily polluted. By the adoption of the washing process, an acid pickling process is removed, and meanwhile the efficiency for removing the organic matter, metal pollutants and the particles can be improved.

Description

technical field [0001] The invention relates to the technical field of sapphire processing and manufacturing, in particular to a cleaning method for a sapphire substrate wafer after polishing. Background technique [0002] At present, sapphire is widely used as the substrate material for making GaN-based LED chips on the market. The quality of ultra-high brightness white / blue LEDs depends on the material quality of gallium nitride epitaxy (GaN), and the impurities on the polished surface of sapphire substrate wafers Contamination can seriously affect the quality and yield of LEDs. In the current LED production, the vast majority of waste products are caused by substrate surface contamination, and in substrate wafer production, almost every process has cleaning problems, so the sapphire substrate cleaning process has an impact on the quality of sapphire substrates very big. [0003] At present, the cleaning methods in the sapphire industry mainly include dry cleaning and we...

AI Technical Summary

Problems solved by technology

At present, most domestic substrate manufacturers will preferentially use sulfuric acid and hydrogen peroxide to remove the oxide layer on the surface of the substrate when using the wet method to clean the substrate wafer. Sulfuric acid and hydrogen peroxide are chemically dangerous when used, and the treatment methods for acidic waste liquid and waste gas are complicated, which is harmful to the environment. However, if citric acid, acetic acid, etc. are used instead of concentrated sulfuric acid, the cleaning The effect is not ideal

[0004] A sapphire wafer cleaning process proposed in Chinese Patent Application No. 201410366227.8 is to use a heated sodium hydroxide solution to ultrasonically clean the oil, then use a heated water-based environmental cleaning machine to ultrasonically clean the dirt, and finally use a heated water-based Environmental cleaning machine ultrasonic cleaning to remove residues, this process reduces the use of strong acidic and strong corrosive lotions, but the cleaning effect is poor for pollution with strong adhesion and smaller particles

[0005] Chinese patent application No. 201310362912.9 proposes an ultrasonic cleaning method for sapphire substrate wafers after polishing, using a mixed cleaning agent formulated with a chelating agent and a surfactant to remove particles while preventing secondary adsorption, and then using an electrolytic diamond film to obtain The strong anodic oxidation solution removes organic matter, which removes the pickling process, but its efficiency in removing organic matter, metal pollutants and particles needs to be improved