CN100435292C - A Non-Selective Etching Method of GaAs/AlGaAs Crystal Material - Google Patents

Abstract

The invention relates to a non-selective corrosion method of GaAs/AlGaAs crystal, wherein the present corrosion liquids main are H2SO4:H2O2:H2O as 1:8:8 or 3:3:1 in volume percentage; and the volume ratio between H3PO4:H2O2:H2O is 1:1:10 or 1:1:5, to corrode at room temperate or ice point, which can produce bar semi-conductor but not round. And the inventive corrosion method uses H3PO4 and H2O2, whose volume ratio is H3PO4:H2O2 as 10:25:1, to corrode under 30-60Deg. C, while it mixing the corrosion liquid at the same time.

Description

A Non-Selective Etching Method of GaAs/AlGaAs Crystal Material

technical field

The invention relates to an etching method for etching semiconductor material GaAs/AlGaAs, which belongs to the technical field of semiconductor device manufacturing.

Background technique

The etching solution used in the existing wet etching method for manufacturing semiconductor devices mainly includes sulfuric acid series and phosphoric acid series, the former such as H ₂ SO ₄ : _{H 2} O ₂ : _{H 2} O volume ratio is 1:8:8 or The 3:3:1 etchant is a typical anisotropic etchant used in the manufacture of ridge waveguide devices; the volume ratio of the latter such as H ₃ PO ₄ : _{H 2} O ₂ : _{H 2} O is 1:1 :10 or 1:1:5 etchant also has obvious anisotropic corrosion characteristics. These etching solutions are usually used to etch GaAs/AlGaAs crystals to make strip semiconductor devices. The corrosion process is usually carried out at room temperature or freezing point temperature (0°C), such as operating at room temperature, or placing the container containing the corrosive liquid in ice water to obtain a stable corrosion rate; during the corrosion process, the corrosive liquid is static.

Contents of the invention

Due to the crystal orientation, material composition and low viscosity of the etchant, the shape of circular devices generally obtained by using the existing etchant is similar to that of a rhombus. Especially when the circle is relatively small, it is difficult to corrode a circular shape that meets the requirements with the existing etching solution. The lower corrosion temperature and the static state of the corrosion liquid promote the tendency of corrosion in the direction. In a nutshell, the existing etching methods exhibit etching direction selectivity in the process of etching GaAs/AlGaAs crystals. In order to realize the non-selective etching of GaAs/AlGaAs crystal, the present invention proposes a non-selective etching method of GaAs/AlGaAs crystal material.

The present invention is achieved in this way, the corrosive solution used is composed of two components with a weight content of 85% H ₃ PO ₄ and a weight content of 30% H ₂ O ₂ , and the volume ratio of each component is H ₃ PO ₄ : H ₂ O ₂ =10～25:1; the corrosion process is carried out at a certain temperature between 30～60°C; at the same time, the corrosion solution rotates in the same direction in the container under the action of external force.

The etching process carried out according to the above technical scheme is non-selective, and can realize the etching of circular GaAs/AlGaAs crystals.

Corrosive solution and ratio (volume) corroded crystal Shape to be corroded Corrosive solution temperature (°C) Stirring rate (rpm) Corrosion result H₃PO₄: H₂O₂: H₂O1:1 : 10 GaAs/AlGaAs round 0 0 diamond H₃PO₄: H₂O₂20:1 GaAs/AlGaAs round 40 100 round

For the purpose of the body, a smooth and uniform circle can be obtained. The corrosive solution is easy to prepare and can be used repeatedly. Its effect can be seen from the table above.

Detailed ways

The corrosion method of the present invention adopts the corrosion solution prepared by two components of H ₃ PO ₄ with a weight content of 85% and H ₂ O ₂ with a weight content of 30%, and the volume ratio of each component is H ₃ PO ₄ : _{H 2} O ₂ =10-25:1. The specific ratio depends on the corrosion rate to be achieved, and the various implementation methods are shown in the table below:

serial number The ratio of H₃PO₄ and H₂O₂ (volume ratio)   Corrosive solution temperature (°C)   Stirring rate (rpm) Corrosion rate (μm/min) 1 10:1 60 200 3.2 2 15:1 50 150 2.5 3 20:1 40 100 2.0 4 25:1 30 50 1.4

The process of corroding GaAs/AlGaAs crystals using the etching method of the present invention is to wipe the GaAs/AlGaAs crystals clean; then spin the glue at a speed of 5000 rpm, and the glue used is AZ-5214 positive glue; Bake for 10 minutes; then align, expose, develop and harden the film to produce the desired circular film. Put the treated GaAs/AlGaAs crystal to be etched into the prepared etching solution, etch at room temperature or heating at a certain temperature in the range of 30-60°C, while stirring in the same direction at a speed of 50-200rpm The etching solution placed in the container, or the container containing the etching solution and the GaAs/AlGaAs crystal to be etched is circularly shaken in the same direction at the same rate until the non-selective wet etching is completed. The etching method of the present invention can be applied in the process of manufacturing semiconductor devices using GaAs/AlGaAs crystal materials, such as ring cavity lasers, and can also be used in the process of manufacturing micro-elements such as microlenses.

Claims (2)

1, a kind of non-selective etching method of GaAs/AlGaAs crystalline material is characterized in that, the corrosive liquid that adopts be 85% H by weight content ₃PO ₄With weight content be 30% H ₂O ₂Two kinds of components are formed, and the volume ratio of each component is H ₃PO ₄: H ₂O ₂==10～25: 1; Corrosion process is carried out under a certain temperature between 30～60 ℃; Corrosive liquid rotates along same direction in container under external force simultaneously.

2, according to the described non-selective etching method of claim 1, it is characterized in that, speed with 50～200rpm stirs the corrosive liquid that is contained in the container along same direction, perhaps go in ring along same direction and shake the container that holds corrosive liquid and wait to corrode the GaAs/AlGaAs crystal, up to finishing non-selective corrosion by same speed.