Deposition method for silicon dioxide thin film of grid sidewall

Abstract

The invention discloses a deposition method for a silicon dioxide thin film of a grid sidewall; the deposition method comprises the following steps of: providing a substrate; placing the substrate in a SACVD (Sub Atmospheric chemical vapor deposition) device; depositing the silicon dioxide thin film on the substrate; carrying out hydrogen relief treatment on the silicon dioxide thin film; repeating the two steps of depositing silicon dioxide thin film on the substrate and carrying out the hydrogen relief treatment till forming the silicon dioxide thin film with a predetermined thickness; and taking out the substrate. According to the deposition method, the deposition process of the whole silicon dioxide thin film is carried out in the recycle manner of multiple depositions and hydrogen relief treatment, so that the content of hydrogen in the silicon dioxide thin film is reduced, the density of the thin film is increased, and the performance of the silicon dioxide thin film of the grid sidewall is improved.

Description

technical field [0001] The invention relates to the field of microelectronics, in particular to a method for depositing a silicon dioxide film. Background technique [0002] Sub Atmospheric Chemical Vapor Deposition (Sub Atmosphere Chemical Vapor Deposition, SACVD) is a widely used chemical vapor deposition technology, which uses ozone and tetraethylsilane (TEOS) as the reaction starting gas. The thermochemical reaction is carried out at low temperature (usually 300-500°C), and because the reaction pressure is generally 50-600torr, which is slightly lower than atmospheric pressure, it is called sub-atmospheric pressure chemical vapor deposition. [0003] In the reaction process of SACVD, the reaction gas does not need to be dissociated by plasma, but the active oxygen atoms in the ozone react with the silicon in TEOS to form silicon dioxide. Therefore, the silicon dioxide film prepared by the SACVD method will There is no plasma-induced damage (Plasma Induced Damage, PID) t...

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Problems solved by technology

Wherein, the silicon dioxide layer 2 is used as an etching stop layer in the silicon nitride etching step, therefore, the quality of the sidewall silicon dioxide film 2 is required to be high, otherwise a relatively thick silicon dioxide layer needs to be used. ; and when the thickness of the layer is thicker, it will affect the size of the entire device, and ultimately affect the performance of the device

[0006] However, in the flow process of the sidewall silicon dioxide deposition method in the prior art, the SACVD film will contain a certain amount of Hydrogen (H) element, the performance of the film is relatively poor, such as high wet etching rate, low density, easy to absorb water, and in some processes that require high film performance, additional heat treatment is required to increase the film. density

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