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US 6,475,915 B1Granted
Ono etch using CL2/HE chemistry
AssigneeAdvanced Micro Devices, Inc.
InventorFei Wang
Life of this patent
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Abstract
An etch process utilizing Cl2/He chemistry for use in a silicon integrated circuit manufacturing process. The etch is a highly nitride selective, anisotropic etch. The process according to an aspect of the invention comprises the steps of etching through a top silicon dioxide layer of an ONO layer with a C12/He plasma etch at a first power, and subsequently etching the underlying nitride layer at a substantially lower second power.
Claims9
An ONO etch process, comprising:
- providing an ONO layer formed over a silicon wafer, the ONO layer comprising a first silicon dioxide layer underlying a silicon nitride layer, and a second silicon dioxide layer overlying said silicon nitride layer;
- selectively etching said second silicon dioxide layer with a plasma at a first power, said plasma comprising chlorine and helium atoms, to expose the silicon nitride layer;
- and
- selectively etching said nitride layer with said plasma at a second power less than said first power to expose said first silicon dioxide layer, whereby the first silicon dioxide layer is not etched.
1 more element
An ONO etch process, comprising:
- initially forming a polysilicon gate structure on the silicon wafer;
- forming a nitride spacer layer over the polysilicon gate structure;
- etching the nitride spacer layer using a plasma comprising a Cl2 and He chemistry to form a nitride bit line over the polysilicon gate;
- forming an ONO layer over the nitride bit line, the ONO layer comprising a first silicon dioxide layer underlying a silicon nitride layer, and a second silicon dioxide layer overlying the silicon nitride layer;
- selectively etching said second silicon dioxide layer with a plasma at a first power, the plasma comprising chlorine and helium atoms, to expose the silicon nitride layer;
- and
- selectively etching said nitride layer with the plasma at a second power less than the first power to expose the first silicon dioxide layer, whereby the first silicon dioxide layer is not etched.
4 more elements
Dependencies are inferred from the claim text.