Dismiss
InnovationQ will be updated on Sunday, Oct. 22, from 10am ET - noon. You may experience brief service interruptions during that time.
Browse Prior Art Database

RF Reactive Ion Etching of Polysilicon with Fluorocarbon Gas

IP.com Disclosure Number: IPCOM000084486D
Original Publication Date: 1975-Nov-01
Included in the Prior Art Database: 2005-Mar-02
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Bondur, JA: AUTHOR [+2]

Abstract

Polysilicon layers are selectively etched without substantial attack of underlying silicon nitride layers.

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 100% of the total text.

Page 1 of 1

RF Reactive Ion Etching of Polysilicon with Fluorocarbon Gas

Polysilicon layers are selectively etched without substantial attack of underlying silicon nitride layers.

A silicon wafer, having a coating of polysilicon overlying layers of silicon nitride and SiO2, is coated with photoresist which is exposed patternwise and developed to form a relief image. The wafer is placed on a quartz cathode plate in a chamber and the chamber is evacuated below 1 micron of Hg.

CCl(2)F(2) gas is bled into the chamber to a pressure of 1-7 microns Argon is then mixed with the CCl(2)F(2) to a total pressure of 90 microns. The gas mixture is then ionized with a 13.56 MHz RF generator at 0.3 watt/cm/2/. The exposed polysilicon is etched at a rate of about 1350 angstrom/min. Silicon nitride etches at 200 angstrom/min for these same conditions.

The etch cycle is controlled by time (total polysilicon thickness divided by established etch rate in angstrom/min) and also visual observation. The etch bias and tolerance can be controlled to 20 Mu "+/- 20 Mu". The selective etching is obtained using a quartz cathode and a range of about 14 to 40% by weight CCl(2)F(2) in argon.

1