Substrate etching method

Abstract

The substrate etching method provided by the present invention includes the following steps: a main etching step, feeding etching gas and auxiliary gas into the reaction chamber, and turning on the excitation power supply and the bias power supply to etch the substrate to a predetermined etching depth , wherein the auxiliary gas includes fluoride gas; in the over-etching step, the etching gas is introduced into the reaction chamber, and the excitation power supply and the bias power supply are turned on to adjust the groove morphology of the substrate. The substrate etching method provided by the invention can not only improve the flexibility of the process, but also improve the flatness of the bottom of the groove of the substrate.

Description

technical field [0001] The invention relates to the technical field of microelectronics, in particular to a substrate etching method. Background technique [0002] PSS (Patterned Sapp Substrates, patterned sapphire substrate) technology is a method commonly used to improve the light extraction efficiency of GaN (gallium nitride)-based LED devices. During the PSS process, the surface of the substrate is usually etched by ICP technology to form a required pattern, and then a GaN film is grown on the surface of the etched substrate by an epitaxial process. The better the flatness of the bottom of the substrate trench obtained by the etching process, the better the subsequent epitaxial process, and the higher the crystal quality of the epitaxial GaN thin film. [0003] At present, when using inductively coupled plasma (Inductively Coupled Plasma, hereinafter referred to as ICP) equipment to etch the surface of the substrate, for example, in a 12-inch ICP equipment, BCl is usual...

AI Technical Summary

Problems solved by technology

[0005] First, in the main etching step, since only BCl 3 As an etching gas, the type of etching gas is single, resulting in a small process adjustment window of the above-mentioned PSS etching process, thereby reducing the flexibility of the process

[0006] Second, during the main etching step, due to the BCl 3 The ionized particles generated by ionization under the condition of glow discharge, the BCl contained in it x The number of particles is large, while the number of Cl radicals is small, resulting in the proportion of high-energy ions that play a role in physical etching is higher than that of free radicals that play a role in chemical etching, which makes the sputtering to the bottom of the trench The density of the ion flow is high, and since the sidewall of the trench reflects the ion flow sputtered onto it towards the corner of the sidewall and the bottom, the corner is more scratched due to the increased density of the ion flow. etch, so that with the accumulation of etching time, a groove is finally formed at the corner, such as figure 2 As shown, this will cause the bottom of the substrate groove to be uneven, which will adversely affect the subsequent epitaxial process and reduce the quality of the epitaxial film

Images