Reduction of polysilicon residue in a trench for polysilicon trench filling processes
First Claim
1. A method of fabricating a semiconductor device, comprising:
- forming at least one trench from a top side of a semiconductor surface, wherein said trench is lined with a trench dielectric liner and filled by a first polysilicon layer;
etching a surface of said trench dielectric liner, wherein dips are formed relative to a top surface of said first polysilicon layer which form a polysilicon protrusion comprising said first polysilicon layer;
etching said first polysilicon layer to remove at least a portion of said polysilicon protrusion;
forming a second dielectric layer over at least said trench after etching said first polysilicon layer;
depositing a second polysilicon layer, andetching said second polysilicon layer to remove said second polysilicon layer over said trench and provide a patterned second polysilicon layer without substantially recessing from said top side of said semiconductor surface.
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Abstract
A method of fabricating a semiconductor device includes forming at least one trench from a top side of a semiconductor layer, wherein the trench is lined with a trench dielectric liner and filled by a first polysilicon layer. The surface of the trench dielectric liner is etched, wherein dips in the trench dielectric liner are formed relative to a top surface of the first polysilicon layer which results in forming a protrusion including the first polysilicon layer. The first polysilicon layer is etched to remove at least a portion of the protrusion. A second dielectric layer is formed over at least the trench after etching the first polysilicon layer. A second polysilicon layer is deposited. The second polysilicon layer is etched to remove it over the trench and provide a patterned second polysilicon layer on the top side of the semiconductor layer.
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Citations
12 Claims
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1. A method of fabricating a semiconductor device, comprising:
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forming at least one trench from a top side of a semiconductor surface, wherein said trench is lined with a trench dielectric liner and filled by a first polysilicon layer; etching a surface of said trench dielectric liner, wherein dips are formed relative to a top surface of said first polysilicon layer which form a polysilicon protrusion comprising said first polysilicon layer; etching said first polysilicon layer to remove at least a portion of said polysilicon protrusion; forming a second dielectric layer over at least said trench after etching said first polysilicon layer; depositing a second polysilicon layer, and etching said second polysilicon layer to remove said second polysilicon layer over said trench and provide a patterned second polysilicon layer without substantially recessing from said top side of said semiconductor surface. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method of fabricating a semiconductor device, comprising:
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forming a termination trench and forming a plurality of active area trenches surrounded by said termination trench from a top side of a silicon surface, lining said termination trench and said plurality of active area trenches with a trench dielectric liner; filling said termination trench and said plurality of active area trenches with a first polysilicon layer, etching a surface of said trench dielectric liner, wherein dips in said trench dielectric liner are formed relative to a top surface of said first polysilicon layer which form a protrusion comprising said first polysilicon layer in said termination trench; etching said first polysilicon layer to remove at least a portion of said protrusion; forming a second dielectric layer over at least said termination trench after etching said first polysilicon layer; depositing a second polysilicon layer, and etching said second polysilicon layer to remove said second polysilicon layer over said termination trench and provide a patterned second polysilicon layer without substantially recessing from said top side of said silicon surface.
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Specification