Out-of-the-box sapphire wafer cleaning process

Abstract

The invention discloses a cleaning process for an epi-ready sapphire wafer. The cleaning process comprises the following steps of: firstly performing ultrasonic vibratory cleaning on the sapphire wafer more than once by using a cleaning agent and ultrapure water so as to remove dirt and fine particles on the surface of the wafer; secondly, brushing the wafer so as to remove large particles on thesurface of the wafer; then spraying an emulsifying agent to the wafer so as to control the adsorption state of the surface of the wafer; then spraying an organic solvent to the wafer so as to avoid the secondary adsorption of contaminants; and finally drying the wafer by using a spin dryer, keeping the wafer still and drying the wafer. When the sapphire wafer cleaned by the cleaning process is putinto the PSS production, the relatively high yield of finished products can be obtained under the condition of directly using the wafer.

Description

technical field [0001] The invention relates to the technical field of sapphire processing, in particular to a sapphire wafer cleaning process that can be used out of the box. Background technique [0002] At present, sapphire has been widely used as the substrate material for making GaN-based LED chips on the market. However, due to the large lattice mismatch thermal expansion coefficient difference between nitride and sapphire, the nitride material grown on the substrate has dislocations and defects. The high density affects the luminous efficiency and life of the device. The patterned substrate (PSS) technology can effectively reduce the dislocations and defects of epitaxial materials, and is widely used in the preparation of nitride devices. [0003] In PSS production, if there is contamination or metal ions on the surface of the sapphire wafer, in the photolithography process, the impurities will cause uneven coating and poor wetting, resulting in unclear images, change...

AI Technical Summary

Problems solved by technology

[0002] At present, sapphire has been widely used as the substrate material for making GaN-based LED chips on the market. However, due to the large lattice mismatch thermal expansion coefficient difference between nitride and sapphire, the nitride material grown on the substrate has dislocations and defects. The density is high, which affects the luminous efficiency and life of the device. The patterned substrate (PSS) technology can effectively reduce the dislocations and defects of epitaxial materials, and is widely used in the preparation of nitride devices.

[0003] In PSS production, if there is contamination or metal ions on the surface of the sapphire wafer, in the photolithography process, the impurities will cause uneven coating and poor wetting, resulting in unclear images, changes in height and size, and greatly reducing the quality of the finished product. Therefore, before the wafer is put into PSS patterned substrate production, it is necessary to add a pre-cleaning operation, and the cleaning quality of the sapphire wafer is particularly important.

[0004] The inventor found through investigation and research that when the sapphire wafers cleaned by the traditional cleaning process are used in PSS production, the yield rate of the finished product is only 70% at the highest. In order to improve the yield rate, it may need to be cleaned again