Method for etching 111 silicon surface on 001 surface silicon wafer

Abstract

The method discloses a method for etching a 111 silicon surface on a 001 surface silicon wafer, and relates to a semiconductor MEMS device. The method comprises following steps: after the (001) surface silicon wafer is washed; removing a surface oxide layer by BOE; growing a layer of SiO2 thin film on the surface of the (001) surface silicon wafer as a mask film; photoetching and developing rectangle and square figures along a (110) crystal orientation; then postbaking; placing the silicon wafer in the BOE to remove partial SiO2 mask film which is not protected by photoresist; removing the photoresist; placing a sample in a KOH solution for etching; placing the etched silicon wafer in sulfuric acid hydrogen peroxide solutions; reacting; and then washing by water, thus etching the 111 silicon surface on the 001 surface silicon wafer. The etched surface roughness resulted from the low concentration KOH is overcome; the negative factor of low etching rate resulted from the high concentration KOH is overcome; the side etching can be ignored; the technology cycle is shortened effectively; and the cost is reduced.

Description

technical field [0001] The invention relates to a semiconductor MEMS device, in particular to a method for etching a 111 silicon surface on a 001 surface silicon wafer. Background technique [0002] Silicon materials have excellent properties such as ideal elastic properties and heat transfer properties, small thermal expansion coefficient, easy integration, and high strength. Silicon materials are designed with three-dimensional structures such as various pits and grooves through processing technology, and corresponding MEMS structures are prepared. Anisotropic wet etching of silicon is a widely used method in the preparation of MEMS structures. The surface flatness and etching rate of KOH solution etching silicon cannot be taken into account at the same time, that is to say, a better surface can be obtained when etching with high concentration KOH solution Flatness but the rate is too slow, and the use of low-concentration KOH solution can increase the corrosion rate but ...

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Problems solved by technology

Anisotropic wet etching of silicon is a widely used method in the preparation of MEMS structures. The surface flatness and etching rate of KOH solution etching silicon cannot be taken into account at the same time, that is to say, a better surface can be obtained when etching with high concentration KOH solution Flatness but the rate is too slow, and the use of low-concentration KOH solution can increase the corrosion rate but the corroded surface is very rough (Irena Zubel et al. published in Sensors and ActuatorsA entitled "The effect of isopropyhalcoholonetchingrateandroughnessof(100)SisurfaceetchedinKOHandTMAHsolutions."The third page mentioned in 80 ℃, when the KOH concentration is lower than 7mol / L, the corrosion rate increases with the increase of the concentration, and when it is higher than 7mol / L, the corrosion rate decreases with the increase of the concentration, the maximum corrosion rate is 0.9um / min, the corrosion rate The faster the rate, the rougher the obtained (111) surface

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