Silicon atomic layer etching method

Abstract

The invention discloses a silicon atomic layer etching method. The silicon atomic layer etching method comprises the following steps: 1, putting a silicon wafer to be etched into a reaction chamber; 2, introducing oxidizing atmosphere gas into the reaction chamber, ionizing the oxidizing atmosphere gas into plasma, and enabling exposed surface atoms of the silicon wafer to be subjected to oxidation reaction to generate a solid silicon-oxygen reaction product; 3, introducing etching gas into the reaction chamber, ironizing the etching gas into plasma, and etching the silicon-oxygen reaction product, wherein the etching rate of the plasma formed by the etching gas to the silicon wafer is smaller than that of the plasma to the silicon-oxygen reaction product. According to the method, the number of layers of atoms needing to be etched can be accurately controlled, and meanwhile, advanced etching is avoided.

Description

technical field [0001] The invention relates to the field of semiconductor technology, and more specifically, to a silicon atomic layer etching method. Background technique [0002] Conventional etching equipment continuously and non-selectively etch wafers, and this system has been used by chip manufacturers for many years. When the integrated circuit enters the technology node of 7nm and below, the electrode in the traditional etching equipment excites the plasma to bombard the wafer under high temperature and high pressure, which will damage the chip structure and cause yield loss. Therefore, for this device structure or some other structure, it is necessary Selectively remove the target material without damaging other parts, and at the same time put forward more stringent requirements for CD uniformity. Therefore, atomic layer etching (ALE) technology has been applied to advanced etching processes. [0003] A single etching cycle of atomic layer etching (ALE) generally...

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Problems solved by technology

[0005] (1) Generally, the ALE surface atom conversion process is divided into two types, plasma-free and plasma-free. The single-atom conversion process occurs on the surface of the plasma-free film layer. This process is very slow and cannot meet the actual mass production requirements; while with plasma The multi-atomic layer conversion process occurs on the surface of the film layer of the body, and the conversion process is accelerated, but there is a risk of premature etching reaction

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