Method for relieving wafer shaking in tunnel oxide layer growth process

Abstract

The invention discloses a method for relieving wafer shaking in a tunnel oxide layer growth process. The method comprises the following steps of performing the tunnel oxide layer growth process on a semiconductor substrate firstly; then performing an annealing process on the semiconductor substrate which is subjected to the tunnel oxide layer growth process; performing heating on the reaction cavity, and pumping hydrogen and oxygen to enable the air pressure in the reaction cavity to be kept unchanged; performing an annealing reaction for a certain time; stopping heating on the reaction cavityto lower the temperature in the reaction cavity; closing hydrogen and reducing the oxygen pumping amount, and meanwhile, pumping nitrogen to enable the air pressure in the reaction cavity to be keptunchanged; and after cooling is completed, completing the annealing process. By virtue of improvement of the ISSG annealing process and by performing technical analysis and understanding on wafer deformation, a defect-causing reason is found and then technical flow and parameters are changed, so that the problem of shaking of a silicon wafer in the high-temperature process can be solved; and afterthe method is adopted, the yield of the silicon wafer can be improved by 5% or above.

Description

technical field [0001] The invention relates to a semiconductor process, in particular to a method for improving wafer shaking in a tunnel oxide layer growth process. Background technique [0002] For floating gate (floating gate) products, tunnel oxide (TUNNEL OX, tunnel oxide) is a crucial core process in the entire process, and the temperature uniformity during the growth of tunnel oxide (TUNNEL OX) is the key Index, which determines the quality of the edge growth coverage (overlay) in the subsequent lithography (Litho) process, and also affects the defects and product yield at the edge of the product silicon wafer. At present, in the industry, the tunnel oxide layer is usually made using In-situ steam generation (ISSG, in-situ steam generation) annealing process, the wafer deformation problem has always been a difficult problem in the ISSG process. It determines whether the subsequent process can go smoothly, and also affects the edge of the product silicon wafer. Cover...

AI Technical Summary

Problems solved by technology

At present, in the industry, the in-situ steam generation (ISSG, in-situ steam generation) annealing process is usually used to make the tunneling oxide layer. The wafer deformation problem has always been a difficult problem in the ISSG process, which determines whether the subsequent process The ability to proceed smoothly also affects the overlay and yield of the edge of the product silicon wafer

The conversion of gas in the process will cause changes in air pressure, such as Figure 1-5 As shown, the high-speed rotating wafer (wafer) shakes, which in turn causes the wafer to deform at high temperature

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