Silicon chip etching method

Abstract

The silicon chip etching process includes three steps including an initial etching, a main etching and a post etching. The main etching step adopts technological gas of CHF3, O2 and SF6 mixture in the flow rate of 10-500 sccm and pressure of 4-100 material; an upper RF power source SFR to ionize the gas mixture filled into the reaction cavity into plasma and a lower RF power source BFR to accelerate the plasma bombarding the surface of the silicon chip. In the step, F* free radical and Si react to form SiFx; SiFx is oxidized by O2 in the gas mixture to form SiOxFy attached to the side wall of the etched channel to constitute a protecting layer and to make the etched side wall smooth and flat. The process is suitable for etching silicon chips of all types, especially polycrystalline silicon layer in line width smaller than 90 nm.

Description

technical field [0001] The invention relates to a semiconductor silicon chip processing technology, in particular to a silicon chip etching process. Background technique [0002] At present, microelectronic technology has entered the era of VLSI and system integration, and microelectronic technology has become the symbol and foundation of the entire information age. [0003] In microelectronics technology, to manufacture an integrated circuit, it needs to go through several processes such as integrated circuit design, mask manufacturing, raw material manufacturing, chip processing, packaging, and testing. In this process, etching the semiconductor silicon wafer to form process trenches is the key technology. [0004] Commonly used etching methods include wet etching and dry etching. Wet etching refers to the method of etching by chemical reaction using liquid chemical reagents or solutions; dry etching mainly uses low-voltage discharge The ions or radicals (molecules, atom...

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Problems solved by technology

During the polysilicon etching process, this kind of process gas has a high vapor pressure of the reaction product, which is easy to volatilize into the gas phase and be discharged as a gas, so it has a faster etching rate, but at the same time, the protection formed on the side wall of the etching groove The layer material is also easy to break away from the surface of the side wall and migrate into the gas phase to volatilize, so that the side wall of the etching tank cannot be effectively protected, the surface of the side wall of the etching tank is rough, and the characteristic structure of the etching is difficult to guarantee, and it is difficult to meet the requirements of the etching process. Dimensional and etch appearance requirements

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