A method for protecting the back structure

Abstract

The invention provides a back structure protecting method. The method is about growing a protective layer on the back side of a wafer to protect the back structure of the wafer. The method comprises the steps of providing a wafer which is provided with a back structure, growing or depositing an oxide layer on the back side of the wafer, depositing a silicon nitride layer on the oxide layer on the back side of the wafer, and conducting subsequent technological fabrication. Compared with the prior art, the method has the advantage that the purpose of protecting the back side of the wafer is realized by growing the protective layer on the back side of the wafer, the silicon nitride layer serves as the outmost protective layer, and the back structure of the wafer is prevented from being affected by other technological processes by means of the fact that impurities are low in diffusivity and not prone to oxidation in silicon nitride. The method is easy to implement and high in control precision, the technology is simple, and the back structure of the wafer can be well protected without affecting the front side.

Description

technical field [0001] The invention relates to the field of semiconductor manufacturing, in particular to a method for protecting a back structure. Background technique [0002] At present, in the manufacturing process of semiconductor devices, it is necessary to perform ion implantation and well pushing process on the wafer. Usually, the well pushing time is long and the temperature is high. Therefore, for some semiconductor devices with back structure, during the well pushing process, The pattern or implanted area on the back of the wafer is easily affected by other steps in the process: on the one hand, when the wafer is in the push-well furnace, the impurities in the push-well furnace tube itself will re-dope the back of the wafer, making the original back-side injection Changes in concentration or junction depth will eventually lead to device parameter degradation or failure; moreover, oxidation will also cause changes in the concentration on the back surface of the wa...

AI Technical Summary

Problems solved by technology

[0002] At present, in the manufacturing process of semiconductor devices, it is necessary to perform ion implantation and well pushing process on the wafer. Usually, the well pushing time is long and the temperature is high. Therefore, for some semiconductor devices with back structure, during the well pushing process, The pattern or implanted area on the back of the wafer is easily affected by other steps in the process: on the one hand, when the wafer is in the push-well furnace, the impurities in the push-well furnace tube itself will re-dope the back of the wafer, making the original back-side injection Changes in concentration or junction depth will eventually lead to device parameter degradation or failure; moreover, oxidation will also cause changes in the concentration on the back surface of the wafer, or changes in the required pattern, which will lead to product failure

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