Method for thermally oxidizing wafer to generate oxide layer

Abstract

The invention relates to a method for generating an oxide layer by wafer thermal oxidation. The method comprises the following steps: placing wafers which need oxidizing in a furnace tube, and heating the furnace tube through a heater; introducing oxygen gas and hydrogen gas into a reactor for mixed burning; introducing vapor generated after burning and the residual oxygen gas from a gas inlet of the furnace tube into the furnace tube; introducing nitrogen gas from the gas inlet of the furnace tube to discharge the gas in the furnace tube through a gas outlet of the furnace tube, wherein half of the flow of the introduced hydrogen gas plus the flow of the introduced oxygen gas equals the flow of the introduced nitrogen gas. By redesigning the flow of the introduced hydrogen gas and the flow of the introduced oxygen gas, the flows of the gas in the furnace tube before and after nitrogen gas introducing stay the same, so that the time of the wafers at different locations in the furnace tube reacting with the vapor and the oxygen gas is equal. Therefore, the oxide layer can achieve good thickness uniformity.

Description

technical field [0001] The invention relates to the field of semiconductor manufacturing, in particular to a method for thermally oxidizing a wafer to form an oxide layer. Background technique [0002] With the continuous development of semiconductor technology, the requirement for the uniformity of gate oxide thickness is continuously improved. Therefore, improving the uniformity of wafer-to-wafer (WTW) thickness in the furnace tube plays a very important role in improving the yield of products. [0003] see figure 1 , taking a traditional 8-inch vertical furnace tube for wet oxygen oxidation of wafers as an example. The oxidation process is to first pass an appropriate amount of hydrogen and oxygen into a reactor outside the furnace tube, and then mix and burn to generate water vapor , water vapor and the remaining unreacted oxygen pass into the furnace tube from the air inlet at the top of the furnace tube, react with the wafer in the furnace tube to form silicon dioxid...

AI Technical Summary

Problems solved by technology

[0009] Based on this, it is necessary to address the problem of poor uniformity of the oxide layer thickness generated in the traditional wet oxygen oxidation method, and provide a method that can make the wafers at different positions in the furnace tube react with water vapor and oxygen at the same time, and improve the furnace tube. Oxide Layer Thickness Uniformity of Produced Wafer Thermal Oxidation Wafer Generation Oxide Layer Method

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