Method of etching a polysilicon pattern
First Claim
1. A method of etching a composite comprising a dielectric underlayer, a polysilicon layer on the dielectric underlayer, and a dielectric coating on the polysilicon layer, which method comprises:
- removing portions of the dielectric coating with a first etchant to form a dielectric pattern comprising sidewalls on the polysilicon layer, whereby a passivating coating is formed on at least a sidewall of the dielectric pattern and on the polysilicon layer;
anisotropically etching the passivating coating with a second etchant to expose a portion of the polysilicon layer leaving a portion of the passivating coating on at least the sidewall of the dielectric pattern; and
etching the polysilicon layer with a third etchant to form a polysilicon pattern.
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Accused Products
Abstract
Pitting in active regions along the edges of a gate electrode when etching a composite comprising an anti-reflective coating on polysilicon is avoided by etching the anti-reflective coating with an etchant that forms a protective passivating coating on at least the sidewalls of the etched anti-reflective pattern and on the underlying polysilicon layer. Subsequently, anisotropic etching is conducted to remove the protective passivating coating from the surface of the polysilicon layer, leaving the etched anti-reflective pattern protected from the main polysilicon etch on at least its sidewalls by the passivating coating to prevent interaction. In another embodiment, the anti-reflective coating is etched without formation of a passivating coating, and the polysilicon layer subsequently etched with an etchant that forms a passivating coating.
107 Citations
47 Claims
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1. A method of etching a composite comprising a dielectric underlayer, a polysilicon layer on the dielectric underlayer, and a dielectric coating on the polysilicon layer, which method comprises:
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removing portions of the dielectric coating with a first etchant to form a dielectric pattern comprising sidewalls on the polysilicon layer, whereby a passivating coating is formed on at least a sidewall of the dielectric pattern and on the polysilicon layer; anisotropically etching the passivating coating with a second etchant to expose a portion of the polysilicon layer leaving a portion of the passivating coating on at least the sidewall of the dielectric pattern; and etching the polysilicon layer with a third etchant to form a polysilicon pattern. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 32)
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21. A method of manufacturing a semiconductor device, which method comprises:
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depositing a dielectric underlayer; depositing a layer of polysilicon on the dielectric underlayer; forming a dielectric coating on the polysilicon layer; removing a portion of the dielectric coating with a first etchant to form a dielectric pattern comprising sidewalls on the polysilicon layer, whereby a passivating polymer-containing coating is formed on at least a sidewall of the dielectric pattern and on the polysilicon layer; anisotropically etching the passivating coating with a second etchant to expose a portion of the polysilicon layer leaving a portion of the passivating coating on at least the sidewall of the dielectric pattern; and etching the polysilicon layer with a third etchant to form a pattern. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 33)
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34. A method of etching a composite comprising a dielectric underlayer, a polysilicon layer on the dielectric underlayer, and a dielectric coating on the polysilicon layer, which method comprises:
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removing portions of the dielectric coating with a first etchant to form a dielectric pattern comprising sidewalls on the polysilicon layer, whereby a passivating coating is not formed on the dielectric pattern or the polysilicon layer; and etching the polysilicon layer with a second etchant to form a polysilicon pattern, whereby a passivating coating is formed on the sidewalls of the etched dielectric pattern while the polysilicon layer is etched. - View Dependent Claims (35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47)
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Specification