Polishing solution for precision polishing of LED sapphire substrate

Abstract

The invention relates to a preparation formula of a polishing solution for precision polishing of an LED sapphire substrate. The polishing solution comprises the following components in percentage by weight: 0.7-1.0% of organic base diethanol amine, 25-35% of silica solution with grain diameter of 50-70nm, 0.4-0.7% of dispersing agent ethanediamine, and 0.1-0.3% of activating agent nonylphenol polyoxyethylene ether. The removal rate of the polishing solution can be up to 28 nm / min; the surface roughness Ra is smaller than 0.5 nm, which can meet the main performance index requirements for sapphire substrate CMP (chemical mechanical polishing). The polishing solution has the advantages of high removal rate, low surface roughness and cost, non-pollution to the environment and non-corrosion to equipment.

Description

technical field [0001] The invention relates to a polishing liquid used for precision polishing of sapphire substrates for LEDs. Background technique [0002] The application of semiconductor material GaN has brought LED to a new level. Because GaN is difficult to prepare bulk materials, thin films must be grown on other substrate materials, because the single crystal sapphire substrate and GaN lattice can match and the single crystal sapphire substrate Its light transmission is good in the visible light range, so sapphire is the most important substrate material. At present, high-quality GaN materials can be epitaxially grown on sapphire, and high-brightness LEDs have been developed. [0003] As a substrate, sapphire has very high requirements for its processing quality. The sapphire substrate as the substrate requires an ultra-smooth, non-damaged surface after metal organic chemical vapor deposition (MOVCD). The current level of domestic sapphire substrates generally has...

AI Technical Summary

Problems solved by technology

[0004] (1) The roughness of the polished surface is relatively large (Ra≥5nm);

[0005] (2) There are serious scratches on the surface of the wafer, and about 20% of the wafer surface has rough and deep marks, which need to be re-polished

Part of the reworked sapphire sheet is prone to the phenomenon that the sapphire thickness is too thin and scrapped due to excessive grinding and polishing

[0006] (3) Improper preparation of polishing liquid not only has high processing costs but also causes environmental pollution due to waste liquid treatment