Plasma etching of semiconductors
AssigneeLam Research Corporation
InventorsWilliam F. Bosch, Helen H. Zhu, Syed A. Haider
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Abstract
A dry etching process for use in the manufacture of silicon integrated circuit devices uses a mixture of about eight parts neon to one part CHF.sub.3 (Freon 23) to form the etching plasma. The process etches doped oxides of silicon, such as BPSG and BPTEOS, in preference to undoped oxides of silicon, silicon nitride, silicides and silicon.
Claims18
A dry etching process for use in the manufacture of silicon integrated circuit devices comprising the steps of:
- positioning in the chamber of a plasma etching apparatus a silicon wafer having a surface layer of a doped oxide of silicon that is to be etched;
- flowing a mixture consisting essentially of CHF.sub.3 and neon into the chamber;
- and
- applying radio frequency energy to the chamber for providing a discharge in the chamber that ionizes the mixture and forms a plasma that etches the surface layer.
A process for the manufacture of silicon integrated circuit devices comprising the steps of:
- preparing a silicon wafer that includes on a silicon surface a plurality of layers including layers of doped and undoped oxides of silicon;
- positioning the wafer on one of the two electrodes of a plasma etching apparatus;
- passing a gaseous mixture consisting essentially of CHF.sub.3 and neon through the apparatus;
- and
- applying a radio frequency voltage between the two electrodes of the apparatus for generating a discharge that ionizes the gaseous mixture and creates a plasma that etches selectively layers of doped oxides of silicon in preference to layers of undoped oxides of silicon.
A process for etching a silicon wafer that includes surface layers of which one is a layer of silicon nitride and another is a layer of a doped oxide of silicon that is to be etched preferentially to the layer of silicon nitride comprising the steps of:
- positioning the silicon wafer to be etched in a plasma etching apparatus;
- and
- flowing a gaseous medium consisting essentially of a mixture of CHF.sub.3 and neon gas through the apparatus to ionize the gaseous medium and create a plasma that etches preferentially the exposed surface of the doped oxide of silicon layer to form an opening in such layer.
The process of claim 14 in which the mixture of CHF.sub.3 and neon is eight parts neon and one part CHF.sub.3.
Dependencies are inferred from the claim text.