Method for selectively etching polysilicon to gate oxide using an insitu ozone photoresist strip
AssigneeMicron Semiconductor, Inc.
InventorDavid J. Keller
Life of this patent
Estimating the term…
Abstract
In semiconductor manufacture, a method of etching a polysilicon layer to a gate oxide in a semiconductor structure is provided. The method is performed insitu in a plasma etch chamber. Initially, an oxide hard mask is formed on the semiconductor structure by etching a deposited oxide layer through a photoresist mask. The photoresist mask is then stripped in the same etch chamber using a high pressure ozone plasma. With the photoresist mask stripped from the semiconductor structure, the polysilicon layer can be etched through the oxide hard mask to the gate oxide with a high etch selectivity.
Claims16
In semiconductor manufacture, a method for etching a silicide layer and a polysilicon layer to a gate oxide layer formed on a substrate, comprising:
- forming an oxide layer on the silicide layer;
- forming a patterned photoresist mask on the oxide layer;
- forming an oxide hard mask by etching the oxide layer through the photoresist mask in an etch chamber of a reactive ion etcher (RIE) using a first gas etchant;
- removing the photoresist mask insitu in the etch chamber using an ozone plasma;
- etching the silicide layer insitu in the etch chamber using the oxide hard mask and a second gas etchant;
- and
- etching the polysilicon layer insitu in the etch chamber using the oxide mask and a third gas etchant.
In a semiconductor structure including a substrate, a gate oxide layer formed on the substrate, a polysilicon layer formed on the gate oxide, and a silicide layer formed on the polysilicon layer, a method of etching the silicide and polysilicon layers, comprising:
- forming an oxide layer on the silicide layer;
- forming a photoresist mask on the oxide layer;
- etching the oxide layer through the photoresist mask in an etch chamber of a reactive ion etcher (RIE) using a first gas etchant to form an oxide hard mask;
- stripping the photoresist mask insitu in the etch chamber using an ozone plasma;
- etching the silicide layer insitu in the etch chamber using a second gas etchant;
- and
- etching the polysilicon layer insitu in the etch chamber using a third gas etchant.
In a semiconductor structure including a silicon substrate, a gate oxide, a polysilicon layer and a silicide layer, a method for etching the polysilicon layer to the gate oxide, comprising;
- forming an oxide hard mask by depositing an oxide layer on the silicide layer, forming a photoresist mask on the oxide layer and etching the oxide layer in an etch chamber of a reactive ion etcher (RIE) using a first etching gas;
- stripping the photoresist mask insitu in the etch chamber using an ozone plasma;
- etching the silicide layer in the etch chamber using the oxide hard mask and a second etch gas;
- and
- etching the polysilicon layer to the gate oxide in the etch chamber using the oxide hard mask and a third etch gas.
Dependencies are inferred from the claim text.