Method for removing silicon ridge produced in epitaxial deposition of super-junction high-pressure device

Abstract

The invention discloses a method for removing silicon ridge produced in epitaxial deposition of a super-junction high-pressure device. The method includes the steps of firstly, depositing a layer of oxide film and / or nitride film on the surface of a silicon chip; secondly etching a deep groove on the silicon chip; thirdly, filling the deep groove with monocrystalline silicon or polycrystalline silicon; fourthly, performing planarization to the surface of the silicon chip by chemical mechanical grinding process, and using the oxide film and / or nitride film as a grinding retaining layer; fifthly, performing back-etching to the part of the oxide film and / or nitride film on two sides of the deep groove by etching process to expose the silicon ridge; and sixthly, etching the silicon ridge to remove by the etching process. The monocrystalline silicon in a bottom cut produced in an oxidation layer due to the fact that etching gas is guided in the epitaxial process can be removed, and accordingly the following gate polycrystalline silicon and the gate oxidation layer are provided with fine surface appearance, the following processes can be prevented from influence of the silicon ridge and certain electric performance of the device is free of influence.

Description

technical field [0001] The invention belongs to the manufacturing process of semiconductor integrated circuits, in particular to a preparation process of a super-junction high-voltage device structure, and in particular to a method for removing silicon ridges produced during the epitaxial deposition process of the super-junction high-voltage device. Background technique [0002] In today's semiconductor technology, deep trench structures are widely used. For example, it is used as an isolation structure to isolate electronic devices with different operating voltages, and it is used in super junction structure semiconductor devices as a P-N junction to achieve high breakdown voltage performance through charge balance in the depletion state, etc. For the latter super junction metal oxide semiconductor field effect transistor, the method of etching and filling the deep trench in the manufacturing process of the super junction MOS transistor is usually: growing a layer of n-type...

AI Technical Summary

Problems solved by technology

In the subsequent oxide film removal process, if the epitaxial layer filled in this part of the incision is not removed, silicon ridges will be formed on both sides of the trench, which will affect the subsequent process, thereby affecting some electrical properties of the device.

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