Etching method of gate sidewall layer on mos surface

Abstract

The invention discloses a method for etching a sidewall layer of a MOS (metal oxide semiconductor) surface gate. The method includes: providing an MOS device comprising a gate, a source, a drain and a sidewall layer, wherein the gate, the source and the drain are disposed on a substrate and the sidewall layer is between the gate and the source and drain; subjecting the MOS device to dry etching to remove part of the sidewall layer, subjecting the MOS device subjected to dry etching to ozone immersion; and subjecting the MOS device subjected to ozone immersion to wet etching. The part of the sidewall layer material is removed by the dry etching while a source and drain doped area is not destructed. A silicon oxide protecting film on the surface the doped area is formed by ozone immersion. During wet etching, phosphoric acid reacts with silicon oxide of the sidewall layer to remove the sidewall layer. The protecting film protects the doped area from being etched by the phosphoric acid. The ozone immersion and wet etching processes are alternate, so that the doped area is further protected. The doped area is protected while the sidewall layer is etched, so that damage of the performance of the MOS device is avoided.

Description

technical field [0001] The invention relates to semiconductor manufacturing technology, in particular to an etching technology on the surface of a MOS device. Background technique [0002] With the development of manufacturing technology, the size of transistors is getting smaller and smaller, and the performance is constantly improving. Among them, the strained silicon technology is indispensable, and currently the strained silicon technology is widely used in the field of semiconductor manufacturing. [0003] The semiconductor manufacturing industry generally agrees to use strained silicon technology to improve the performance of CMOS (Complementary Metal Oxide Semiconductor, Complementary Metal Oxide Semiconductor) devices. For example, applying tensile stress (Tensilestress) in the conductive channel of NMOS (N-Metal-Oxide-Semiconductor, N-type metal oxide semiconductor) devices can improve the electron mobility of NMOS; in PMOS (P-Metal-Oxide-Semiconductor , P-type me...

AI Technical Summary

Problems solved by technology

However, whether it is a dry method or a wet method (usually phosphoric acid), it will cause the destruction of the morphology of the source-drain doped region 5, causing damage to the doped region 5 (such as the loss of the NiPtSi material in the doped region), such as image 3 As shown, thereby reducing the performance of MOS (MetalOxideSemiconductor, metal oxide semiconductor) devices

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