CN107354513B

CN107354513B - High-efficiency stable germanium single crystal wafer etching process

Info

Publication number: CN107354513B
Application number: CN201710816709.2A
Authority: CN
Inventors: 吕菲; 张伟才; 常耀辉; 王云彪; 窦连水; 刘洋
Original assignee: CETC 46 Research Institute
Current assignee: CETC 46 Research Institute
Priority date: 2017-09-12
Filing date: 2017-09-12
Publication date: 2020-05-12
Anticipated expiration: 2037-09-12
Also published as: CN107354513A

Abstract

The invention discloses an etching process capable of efficiently and stably etching a germanium single crystal wafer. Immersing germanium single crystal wafer into NH₄OH：H₂O₂: HF: DIW = 1: 2: 3: 5, wherein the mass concentrations of hydrofluoric acid, hydrogen peroxide and ammonium hydroxide are respectively 40 +/-1%, 30 +/-1% and 25 +/-1%, the mixture is uniformly stirred, the temperature of the corrosive liquid is kept at 50-53 ℃, 10 germanium single wafers are immersed into the corrosive liquid and rotated clockwise for 3min20 s-3 min40s every time, and the thickness of the germanium single wafer can be removed by 16-18 microns. The corrosion speed of the corrosion liquid in the corrosion process is efficient and stable, the temperature and the effective component fluctuation of the corrosion liquid are small, the process conditions are easy to control, the surface of the corroded germanium sheet is uniform and uniform, no corrosion pits exist, the quality is good, and the method is suitable for batch production.

Description

High-efficiency stable germanium single crystal wafer etching process

Technical Field

The invention belongs to the field of semiconductor material processing, and particularly relates to a high-efficiency and stable germanium single-crystal wafer etching process.

Background

Germanium single crystal wafer is an important semiconductor material, and is widely applied to a plurality of fields such as infrared optical devices, nuclear radiation detectors, microelectronic chip technology, aerospace solar cell substrates and the like. Wet chemical etching is one of the main methods for chemical etching processing of germanium single crystal wafer, and H is commonly used at present₂O₂The HF corrosion process is one of the widely used methods in chemical corrosion processing of germanium single crystal wafers, has the functions of removing a damaged layer on the surface of the germanium wafer, releasing stress and the like, and has the defects of rapid temperature change, unstable corrosion rate, rapid change of components of a corrosive liquid, difficulty in control in the batch production process and poor product consistency. Therefore, the invention discloses a new corrosion process, which requires stable temperature of corrosion liquid, stable corrosion rate and solution components in the reaction process, improves the consistency and stability of products, and simultaneously leads germanium to be obtainedThe sheet has no corrosion pit after corrosion, and the surface quality is very necessary.

Disclosure of Invention

In view of H₂O₂The invention provides a high-efficiency and stable germanium single-crystal wafer etching process, wherein the temperature of etchant in the process is stable, the etching rate and solution components are stable, and the surface quality of a germanium wafer after etching is good.

In order to achieve the purpose, the invention adopts the technical scheme that: a high-efficiency stable germanium single-chip corrosion process is characterized in that: immersing the germanium single crystal wafer into an etching solution prepared from ammonium hydroxide, hydrogen peroxide, hydrofluoric acid and deionized water for etching, wherein the etching time is 3min20 s-3 min40s, and the etching temperature is kept at 50-53 ℃; the volume ratio of ammonium hydroxide, hydrogen peroxide, hydrofluoric acid and deionized water in the corrosive liquid is NH₄OH：H₂O₂：HF：DIW=1：2：3：5。

The mass concentrations of hydrofluoric acid, hydrogen peroxide and ammonium hydroxide in the corrosive liquid are respectively 40 +/-1% of hydrofluoric acid, 30 +/-1% of hydrogen peroxide and 25 +/-1% of ammonium hydroxide.

The invention has the advantages and beneficial effects that: the hydrogen peroxide solution is used as an oxidant, the hydrofluoric acid is used as a corrosive agent on one hand, and the hydrofluoric acid and the ammonium hydroxide form ammonium fluoride to serve as a buffer solution on the other hand, so that the buffer solution has the effects of stabilizing the pH value, the reaction temperature and effective components of the solution, further stabilizing the corrosion rate, controlling the formation and the expansion of a corrosion pit, improving the surface quality of the germanium sheet and improving the efficiency and the stability of processing. The method is easy to operate, simple and reliable in theoretical principle, efficient and stable in wafer processing process, easy to control process parameters, uniform and consistent in germanium sheet surface, free of corrosion pits, practical and suitable for batch production, and the surface quality of the corroded germanium sheet meets the later-stage process requirements.

Detailed Description

The invention is further illustrated by the following examples:

example (b): the crystal orientation of the germanium sheet is P <100>, the thickness is 420 μm, and the total thickness is 60 sheets. The surface of the germanium sheet is smooth and clean without damage before corrosion.

Immersing 10 germanium single crystal wafers into an etching solution prepared from ammonium hydroxide, hydrogen peroxide, hydrofluoric acid and deionized water for etching, rotating clockwise, wherein the etching time is 3min and 30s, the etching temperature is 50 ℃, and spin-drying by using a centrifuge after etching to remove the thickness of 16-18 μm.

The volume ratio of ammonium hydroxide, hydrogen peroxide, hydrofluoric acid and deionized water in the corrosive liquid is NH₄OH：H₂O₂: HF: DIW = 1: 2: 3: 5. and stirring uniformly after the preparation of the corrosive liquid is finished. The mass concentration of hydrofluoric acid in the corrosive liquid is 40%; the mass concentration of the hydrogen peroxide is 30 percent; the mass concentration of ammonium hydroxide was 25%.

The change of the temperature of the corrosive liquid in the germanium wafer processing process is recorded in the embodiment, and the data is shown in table 1.

TABLE 1

Serial number	Number of pieces per basket	Temperature before etching	Temperature after etching	Etching rate of mu m/min
					1	10	50.4	52.0	5.39
2	10	50.8	52.4	5.41
					3	10	50.2	51.8	5.38
4	10	50.6	52.4	5.42
					5	10	50.8	52.6	5.39
6	10	50.4	52.2	5.40

It can be seen from table 1 that the temperature fluctuation of the etching solution is small, the etching rate is stable, and the method is suitable for mass production. The surface quality of the germanium sheet is visually inspected after corrosion and observed by a metallographic microscope, the surface of the germanium sheet is uniform, no corrosion pit exists, and the use requirement is met.

And (4) conclusion: the etching process has the advantages of high and stable etching rate, small fluctuation of the temperature and the effective components of the etching solution, high surface quality of the germanium single crystal wafer and capability of completely meeting the later-stage process requirements.

Claims

1. A high-efficiency stable germanium single-chip corrosion process is characterized in that: immersing the germanium single crystal wafer into an etching solution prepared from ammonium hydroxide, hydrogen peroxide, hydrofluoric acid and deionized water for etching, wherein the etching time is 3min20 s-3 min40s, and the etching temperature is kept at 50-53 ℃; the volume ratio of ammonium hydroxide, hydrogen peroxide, hydrofluoric acid and deionized water in the corrosive liquid is NH₄OH：H₂O₂: HF: DIW = 1: 2: 3: 5; the mass concentrations of the hydrofluoric acid, the hydrogen peroxide and the ammonium hydroxide are respectively 40 +/-1% of the hydrofluoric acid, 30 +/-1% of the hydrogen peroxide and 25 +/-1% of the ammonium hydroxide.