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Method for improving corner at top of groove into rounded corner

A trench and fillet technology, applied in the field of integrated circuit semiconductor manufacturing, can solve the problems of inconvenient process methods and high process costs, and achieve the effects of reducing electric field density, eliminating charge accumulation, and improving breakdown voltage

Active Publication Date: 2012-03-21
SHANGHAI HUAHONG GRACE SEMICON MFG CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

But the process methods are not convenient enough, and the process cost is too high

Method used

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  • Method for improving corner at top of groove into rounded corner
  • Method for improving corner at top of groove into rounded corner
  • Method for improving corner at top of groove into rounded corner

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Embodiment Construction

[0019] When a groove is etched on a silicon substrate using a common process, the top corner of the groove is a right angle. On this basis, the present invention deposits a layer of silicon oxide on the trench and the silicon substrate or silicon epitaxial layer as a thin oxide protective layer for the trench, as shown in FIG. 4( a ). This step can use HDPCVD (High Density Plasma Chemical Vapor Deposition) process to deposit silicon oxide, and the reaction gas in the chamber is Ar (argon) or He (helium), O 2 (oxygen), SiH 4 (silane), the thickness of the deposited silicon oxide layer is

[0020] Next, fillet the top corners of the trench. This step uses the plasma bombardment technology of HDPCVD process to etch the oxide film protective layer deposited in the previous step, and the reaction gas is Ar (argon) or He (helium), O 2 (Oxygen), the bombardment bias is 1000-3000W, and the bombardment time is 5-25s, and the plasma bombardment etching in this step and the silicon ...

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Abstract

The invention discloses a method for improving a corner at the top of a groove into a rounded corner, which comprises the following steps after the groove is formed: (1) depositing a layer of silicon oxide in the groove and on a silicon substrate or a silicon epitaxial layer; (2) etching the corner at the top of the groove into the rounded corner by adopting plasma bombardment etching; (3) carrying out sacrificial oxidation to form a sacrificial oxidation film to improve the smoothness of the rounded corner at the top; and (4) removing the residual oxide layer. The invention can improve the corner of the groove, eliminate the charge accumulation and reduce the density of the electric field at the corner, thereby improving the breakdown voltage of a device.

Description

technical field [0001] The invention relates to the field of integrated circuit semiconductor manufacturing, in particular to a method for improving the top corners of trenches into rounded corners. Background technique [0002] Trench structures are widely used in power electronic devices such as metal-oxide-semiconductor field-effect transistors (MOSFETs) and insulated-gate bipolar transistors (IGBTs). Because it transfers the conduction channel from the surface of the silicon wafer to the vertical direction of the silicon wafer, the trench device can integrate more units per unit area than the planar device, thereby greatly reducing the on-resistance and reducing the power consumption. Therefore, in power devices, trench MOSFETs and trench IGBTs have been more and more widely used. [0003] But usually due to the limitations of the trench etching process itself, such as figure 1 As shown, right or negative angles are easily formed at the corners of the top of the trenc...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01L21/3065H01L21/311H01L21/02H01L21/316
Inventor 彭仕敏谢烜彭虎
Owner SHANGHAI HUAHONG GRACE SEMICON MFG CORP