Method for Improving Edge Roughness of Tungsten Silicide Double Gate of Self-Aligned Contact Hole

Abstract

The invention discloses a method for improving tungsten silicide bigrid edge roughness of a self-aligning contact hole. The method comprises the following steps: 1.1 a tungsten silicide grid pattern is formed; 1.2 first time of grid etching is performed on tungsten silicide grid; 1.3 photo-resist is removed by adopting dry etching with a function of modifying morphology of the side wall of tungsten silicide, and then cleaning is performed by adding pure water to rinse; 1.4 dielectric film silicon nitride is deposited; and 1.5 second time of grid etching is performed and residual polycrystalline silicon is etched. In the step of photo-resist removing after completion of first time of etching, a special step of photo-resist removing with carbon tetrafluoride, which is different from a conventional step of photo-resist removing by oxygen, is adopted, and rinsing processing is performed by adding pure water. Partial side wall of tungsten silicide can be etched by the special step of photo-resist removing with carbon tetrafluoride, and the side wall of the tungsten silicide film layer can be modified to be vertical in morphology so that a small dielectric film blocking wall is difficult to form in the subsequent dielectric film deposition and second step of etching, and thus residual in polycrystalline silicon etching can be avoided.

Description

technical field [0001] The invention belongs to a manufacturing process method of a semiconductor integrated circuit, and in particular relates to a method for automatic cleaning of ion implantation equipment, in particular to a method for automatic cleaning of an ion cavity of ion implantation equipment to improve the service life of components. Background technique [0002] The tungsten silicide double gate structure of the self-aligned contact hole uses a multi-layer gate structure of silicon nitride, tungsten silicide, and polysilicon structure. The device has the characteristics of small device area and low production cost, and is widely used in SIM cards and financial cards. And MCU SOC product manufacturing. [0003] In the tungsten silicide double-gate device with self-aligned contact holes, in order to solve the short circuit problem of the self-aligned contact hole to the gate, the traditional gate etching process usually needs to be etched in two steps: the first ...

AI Technical Summary

Problems solved by technology

Due to the limitation of the amount of etching and the large tungsten silicide grains, the first step of etching the bottom of tungsten silicide is easy to form a tilted shape.

Images