Etching method of inner wall, etching gas and preparation method of nanowire device

Abstract

The invention relates to an etching method of an inner wall, an etching gas and a preparation method of a nanowire device, belonging to the field of semiconductor technology, and solves the problem of retaining the side wall material, silicon and top hard mask in the groove in the prior art. The problem that the high material selection ratio cannot be achieved at the same time. Gases used to etch the inner walls of nanowire devices, including CH 2 f 2 、CH 4 , O 2 and Ar, the ratio of each component is 1:1:1:2~1:1:1:5, the upper RF power is 100~1000W during the etching process, the lower RF power is 10~80W; the lower electrode power is 0 ~60W, base temperature is -20~90℃. A method for preparing a nanowire device, comprising the following steps: epitaxial stacking and a hard mask on a substrate; laterally etching a SiGe layer to form a filling void of a predetermined length; depositing an inner wall material; etching and removing the inner side outside the filling void Wall material, forming the inner wall. The invention can not only keep the side wall material in the groove, but also realize high selection ratio of materials such as silicon and top hard mask.

Description

technical field [0001] The invention relates to the technical field of semiconductors, in particular to an etching method of an inner wall, an etching gas and a preparation method of a nanowire device. Background technique [0002] After CMOS enters the 3-5nm technology generation, in order to enhance device gate control and overcome short channel effects, stacked gate-all-around devices (GAA) will be the mainstream development direction, and the inner wall is a very important technology (as shown in the flow chart). It can control the effective gate length and reduce the leakage between the gate and the source and drain and reduce the effect of parasitic capacitance. However, the formation of the inner wall requires precise anisotropy. It has a high selection ratio for materials other than the inner wall, and can strictly control the etching precision. It is necessary to ensure that there is no sidewall material residue at the end of the nanowire, and it must also be concav...

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Problems solved by technology

[0006] In view of the above analysis, the present invention aims to provide an etching method for the inner wall, an etching gas and a method for preparing a nanowire device, so as to solve the problem that the existing etching method retains the side wall material and the silicon and the top in the groove. The problem that the high selection ratio of materials such as hard masks cannot be achieved at the same time

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