Method for preventing crystal defect on fluorine-doped oxide film surface

Abstract

The invention provides a method for preventing crystal-like flaw on the surface of a fluorine-doping oxide film, relating to a process for manufacturing a semiconductor device. In current process, when a wafer having a surface deposited with a fluorine-doping oxide film is exposed to a vapor-containing environment, crystal-like flaw can be formed on the wafer surface in a short time (usually a few hours), resulting in the decrease of wafer yield. According to the method for preventing crystal-like flaw on the surface of a fluorine-doping oxide film, after the fuorine-doping oxide film is deposited on the wafer surface, the wafer is cleaned by weak acid with a pH value between 5 and 7. In this method, fluorine ion and hydrogen ion produced by weak acid electrolysis are integrated to form hydrofluoric acid, so that the hydrofluoric acid can be directly volatilized or washed by water, the fluorine ion amount on the wafer surface is effectively reduced, and crystal-like flaw can not be formed even the cleaned wafer is exposed to the vapor-containing environment.

Description

technical field [0001] The invention relates to a manufacturing process of a semiconductor device, in particular to a method for preventing crystal defects on the surface of a wafer. Background technique [0002] In the manufacturing process of semiconductor devices, when a fluorine-doped oxide film deposited on the surface, such as a wafer of fluorinated silica glass (FSG), is exposed to an environment containing water vapor, fluorine ions and water vapor react to form crystals easily Like precipitates, and with the passage of time, more and more precipitates will form serious crystal-like defects on the surface of the oxide film. These crystal-like defects will form through holes or trenches on the surface of the wafer during the subsequent etching process, which affects the yield of the wafer. [0003] In order to reduce the occurrence of crystal-like defects, the existing method is to shorten the waiting time (Q-time) between the deposition of the fluorine-doped oxide f...

AI Technical Summary

Problems solved by technology

However, for mass production, the length of Q-time is difficult to control, so crystal-like defects cannot be avoided in practical applications