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Shallow trench isolation chemical-mechanical polishing process

  • US 6,424,019 B1
  • Filed: 02/18/2000
  • Issued: 07/23/2002
  • Est. Priority Date: 06/16/1998
  • Status: Expired due to Term
First Claim
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1. A semiconductor wafer wherein trenches are formed in predefined areas, the trenches providing electrical isolation between adjacent active devices formed on the semiconductor wafer, the predefined areas comprising:

  • a semiconductor substrate;

    a native oxide layer deposited on the substrate;

    a first polish stop layer deposited on the native oxide layer;

    a soft material layer deposited on the first polish stop layer and through which trenches are etched in the predefined areas, the trenches extending through the soft material layer, the first polish stop layer, the native oxide layer and a predefined portion of the semiconductor substrate;

    an insulating layer deposited on the soft material layer, which insulating layer fills the trenches, wherein the rate of removal of the soft material layer under chemical-mechanical polishing is between 50% to 200% greater than the rate of removal of the insulating layer under chemical-mechanical polishing and the thickness of the soft material layer is between 1 to 10 times the thickness of the polish stop layer and the polish stop layer has a thickness between approximately 2,000 and approximately 20,000 angstroms.

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