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METHOD FOR FORMING SEMICONDUCTOR DEVICE

  • US 20080064192A1
  • Filed: 08/29/2007
  • Published: 03/13/2008
  • Est. Priority Date: 09/13/2006
  • Status: Active Grant
First Claim
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1. A method comprising:

  • depositing a first oxide layer over a surface of a semiconductor substrate including high voltage and low voltage wells, the first oxide layer having a predetermined thickness corresponding to a high voltage area of the well;

    forming a first photoresist pattern over a surface of the first oxide layer, performing an etching process using the first photoresist pattern as a mask, so that the first oxide layer is selectively etched until the semiconductor substrate is partially exposed, to form a first oxide layer pattern;

    depositing a second oxide layer over a surface of the semiconductor substrate including the first oxide layer pattern using a first photoresist pattern as a mask, the second oxide layer having a predetermined thickness corresponding to a low voltage area of the well;

    removing said first photoresist pattern, and coating a polysilicon layer over the surface of the semiconductor substrate including the first oxide layer pattern and the second oxide layer;

    forming a second photoresist pattern over a surface of the polysilicon layer, performing an etching process using the second photoresist pattern as a mask, so that the polysilicon layer is selectively etched until the first oxide layer pattern and the second oxide layer are partially exposed; and

    removing the second photoresist pattern, performing an impurity ion implantation process using the polysilicon layer, the first oxide layer pattern, and the second oxide layer as a hard mask, to form a drift area in the semiconductor substrate.

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