Gallium arsenide surface chemical etching method and chemical etchant

Abstract

The invention provides a method for chemical etching of gallium arsenide wafers, which includes: using metal cleaner to rinse the gallium arsenide wafers; rinsing the gallium arsenide wafers in ammonia water; putting the gallium arsenide wafers into chemical etchant, etching the surface of each chip at 10-40 DEG C; using deionized water to flush the surface of each chip; and drying the chips. The invention further provides the chemical etchant for chemical etching of the gallium arsenide wafers, which comprises, in mass ratio, 3.2-20% of ammonia water, 8.3-33.0% of hydrogen peroxide and water. By the effective etching process using the chemical liquor, chip affected layers caused by machining procedures are removed, internal stress of the wafers is eliminated, the wafers meeting the requirement on epitaxial growth back roughness are produced, and the wafers have uniform backs and are free of back invasion and back scratch.

Description

Technical field [0001] The invention belongs to the field of semiconductor materials, and particularly relates to a method for chemically etching the surface of a III-V compound semiconductor material gallium arsenide wafer, and a chemical etching solution used in the method. Background technique [0002] Gallium arsenide (GaAs) is one of the important III-V main group compound semiconductor materials. Gallium arsenide single crystal wafers have become an important basic material for the manufacture of optoelectronics and microwave devices, and they are also widely used in the manufacture of ultra-high-speed integrated circuits. (IC). [0003] The development of integrated circuit technology also puts forward higher requirements for wafer materials. Obtaining GaAs substrate wafer materials with good surface quality is crucial to the epitaxial growth of GaAs substrates. The processing of GaAs substrate wafers generally includes cutting, edging, grinding, polishing, cleaning and oth...

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Problems solved by technology

[0005] Zheng Hongjun et al. discussed the influence of different system components, temperature, and heat absorption and release in the corrosion process on the uniformity of the wafer. They proposed to use ammonia water series for chemical etching of GaAs abrasive wafers. The wafer thickness uniformity was 11.47%, which provided a basis for the next step process. Wafers with better flatness, (Zheng Hongjun, Bu Junpeng, Yin Yuhua, etc., Analysis of the Uniformity of Chemical Corrosion of GaAs Grinding Sheets, Journal of Functional Materials and Devices, 2000, 6(4): 335), but this method does not provide a specific etching solution The process parameters of the ratio and corrosion operation are not very operable

[0006] Lv Fei et al. (Lv Fei, Zhao Quan, Yu Yan et al., Control Method of VB-GaAs Wafer Warpage, Process Technology and Materials, 2008, 11:1000) compared alkaline etching solutions with different volume ratios, and selected About 40% alkaline etching solution, the temperature is controlled above 80°C, and the etching time and temperature change during operation are controlled at the same time, which effectively reduces the warpage of gallium arsenide grinding discs and improves the overall yield of processing, but The temperature is not easy to control during the operation of this method, and it is easy to increase the fragmentation rate

[0007] The prior art uses a sulfuric acid system, a solution prepared with sulfuric acid, hydrogen peroxide, and water as the basic components as the corrosion solution. After pre-cleaning the ground wafer, it is put into the corrosion solution for corrosion, and then rinsed and dried. The rate of corrosion is slow, so the corrosion process takes a long time and the efficiency is low

Moreover, due to the long corrosion process of the existing corrosion process, it is not easy to control the temperature change before and after the corrosion liquid, and it is also prone to problems such as back invasion and back flowering.