Method for forming silicon dioxide spacer with uniform thickness

Abstract

The invention provides a method for forming a silicon dioxide spacer with uniform thickness. The method comprises the following steps of: firstly, depositing a spacer oxidation layer on a surface of a device on which a plurality of grids are formed; etching the formed spacer oxidation layer to enable a sealing port formed between two grids of the device in the deposition process to be opened; depositing a spacer oxidation layer on the formed spacer oxidation layer; secondarily etching the formed spacer oxidation layer; and repeating the depositing and etching processes of the spacer oxidation layer until the thickness of the formed spacer oxidation layer reaches a target thickness, wherein the etching is realized by using far-end NF3+NH3 plasma.

Description

technical field [0001] The invention relates to the field of integrated circuit manufacturing, in particular to a method for forming silicon dioxide sidewalls with uniform thickness on the device surface. Background technique [0002] Spacer is a necessary structure in the industry to manufacture semiconductor CMOS devices. It can not only protect the gate, but also reduce the short channel effect well with the shallow doping (LDD) process. [0003] So far, the traditional sidewall process mostly uses a composite layer of silicon dioxide and silicon nitride (silicon nitride is the outer layer). When it comes to the 65nm process and below, the requirements for the deposition of silicon dioxide films are getting more and more High, not only requires a low temperature deposition process (<300~600°C), but also requires good uniformity, especially for different areas (large line width, such as a single polycrystalline gate area and small line width, such as static memory The ...

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Problems solved by technology

In this way, in the case of the same increase in thickness, the film thickness uniformity of the two regions will have a huge difference

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