Semiconductor devices and methods for forming the same
First Claim
1. A method for forming a semiconductor device, comprising:
- providing a substrate;
forming a plurality of trenches in the substrate;
forming an isolation oxide layer in the trenches and on the substrate;
depositing a shield polysilicon in the trenches and on the isolation oxide layer on the substrate;
performing a first etching process to remove a first portion of the shield polysilicon and expose a portion of the surface of the isolation oxide layer in the trenches;
performing a first removal process to remove a first portion of the isolation oxide layer;
performing a second etching process to remove a second portion of the shield polysilicon and expose another portion of the surface of the isolation oxide layer in the trenches;
performing a second removal process to remove a second portion of the isolation oxide layer; and
forming an inter-poly oxide layer on the remaining shield polysilicon and the remaining isolation oxide layer;
wherein the inter-poly oxide layer has a concave top surface.
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Abstract
A method for forming a semiconductor device is provided. A plurality of trenches are formed in the substrate. An isolation oxide layer is formed in the trenches and on the substrate. A shield polysilicon is deposited in the trenches and on the isolation oxide layer on the substrate. A first etching process is performed to remove a first portion of the shield polysilicon. A first removal process is performed to remove a first portion of the isolation oxide layer. A second etching process is performed to remove a second portion of the shield polysilicon. A second removal process is performed to remove a second portion of the isolation oxide layer. An inter-poly oxide layer is formed on the remaining shield polysilicon and the remaining isolation oxide layer, wherein the inter-poly oxide layer has a concave top surface.
11 Citations
10 Claims
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1. A method for forming a semiconductor device, comprising:
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providing a substrate; forming a plurality of trenches in the substrate; forming an isolation oxide layer in the trenches and on the substrate; depositing a shield polysilicon in the trenches and on the isolation oxide layer on the substrate; performing a first etching process to remove a first portion of the shield polysilicon and expose a portion of the surface of the isolation oxide layer in the trenches; performing a first removal process to remove a first portion of the isolation oxide layer; performing a second etching process to remove a second portion of the shield polysilicon and expose another portion of the surface of the isolation oxide layer in the trenches; performing a second removal process to remove a second portion of the isolation oxide layer; and forming an inter-poly oxide layer on the remaining shield polysilicon and the remaining isolation oxide layer; wherein the inter-poly oxide layer has a concave top surface. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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Specification