Cap layer etching optimization method

Abstract

The invention discloses a Cap layer etching optimization method. The method comprises the following steps: S1, preparing an epitaxial wafer of a full structure; S2, carrying out warping compensation on the N surface of the epitaxial wafer; S3, depositing a layer of optical film on the Cap layer on the P surface of the epitaxial wafer; S4, performing ohmic contact photoetching on the epitaxial wafer deposited with the optical film to enable the edge of the photoresist to have an inclination angle; S5, etching off the optical film beyond the coverage range of the photoresist by using dry etching; S6, carrying out ohmic contact metal deposition, and depositing metal in the etched area, so that the deposited metal is in close contact with the dip angle of the edge of the photoresist and the Cap layer; and S7, removing the photoresist by using an SN830 solution. Through the process method, the deposited metal is tightly attached to the photoresist, the phenomenon that an SN830 solution etches the Cap layer is avoided, the selection ratio is increased, the etching angle is conveniently controlled, the yield of the chip is improved, and the performance of the chip is greatly protected.

Description

Technical field [0001] The present invention relates to the field of chip preparation, and more particularly to a CAP Layer layer etch optimization method. Background technique [0002] The VCSEL chip is made of an excess delay as a base film, and the corresponding process flow is made on the epitaxial sheet. The epitaxial sheet consists of a Cap Layer layer, a P-DBR, N-DBR, a oxide layer, a quantum well and a substrate, which will affect the reliability or photoelectric properties of the chip. [0003] During the preparation of the VCSEL chip, when the optical film deposition, photolithography, etching, etching and metal deposition is performed on the CAP Layer layer of the epitaxial piece, and the Sn830 solution is used to wash the epitaxial sheet, and the residual remaining in the epitaxial LED in the film. Among them, the photolithography process is to remove partial photoresist, exposing the optical film; the etching step is to remove the optical film of the photolithography...

AI Technical Summary

Problems solved by technology

However, in the current metal deposition step, the edge metal deposited on the Cap layer cannot be closely attached to the optical film, and there will be certain gaps (such as figure 1 SEM picture), when using SN830 solution to clean the residual photoresist, the SN830 solution is very easy to soak into the Cap layer from the gap, dissolve part of the Cap layer, cause certain damage to the Cap layer, and finally affect the chip. Optoelectronic characteristics and reliability

[0004] Therefore, it is urgent to solve the problem that the edge of the optical film cannot be closely attached to the metal during metal deposition, and seek a method that can protect the Cap layer layer from etching

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