Semiconductor devices and methods for forming the same
First Claim
1. A semiconductor device, comprising:
- a substrate, comprising trenches;
an isolation oxide layer, disposed in the trenches;
a shield polysilicon, disposed in the trenches and partially surrounded by the isolation oxide layer; and
an inter-poly oxide layer, disposed on the isolation oxide layer and on the shield polysilicon;
wherein the inter-poly oxide layer has a concave top surface; and
a first top surface portion of the isolation oxide layer adjacent to the sidewall of the shield polysilicon has a first curvature, and a second top surface portion of the isolation oxide layer adjacent to a sidewall of one of the trenches has a second curvature, wherein the first curvature is greater than the second curvature.
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Accused Products
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.
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Citations
19 Claims
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1. A semiconductor device, comprising:
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a substrate, comprising trenches; an isolation oxide layer, disposed in the trenches; a shield polysilicon, disposed in the trenches and partially surrounded by the isolation oxide layer; and an inter-poly oxide layer, disposed on the isolation oxide layer and on the shield polysilicon; wherein the inter-poly oxide layer has a concave top surface; and a first top surface portion of the isolation oxide layer adjacent to the sidewall of the shield polysilicon has a first curvature, and a second top surface portion of the isolation oxide layer adjacent to a sidewall of one of the trenches has a second curvature, wherein the first curvature is greater than the second curvature. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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Specification