Browse Prior Art Database

Polymerization Detection in Reactive Ion Etching

IP.com Disclosure Number: IPCOM000048582D
Original Publication Date: 1982-Feb-01
Included in the Prior Art Database: 2005-Feb-08
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Frieser, RG: AUTHOR [+4]

Abstract

Polymer formation, which is undesirable in dry etching by reactive ion etching, is detected at an early stage by monitoring the cathode DC voltage.

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

Page 1 of 1

Polymerization Detection in Reactive Ion Etching

Polymer formation, which is undesirable in dry etching by reactive ion etching, is detected at an early stage by monitoring the cathode DC voltage.

Polymer formation in reactive ion etching apparatus, using either fluorocarbons containing hydrogen or added hydrogen, can cause changes in etch rate ratios which are uncontrollable and undesirable.

Polymer formation can be detected by either monitoring the etch rates by laser end-point detection or by monitoring pressure changes in the system. However, by the time that these changes in pressure and etch rate are observed. it is too late to save the current etch run. Polymer formation can be detected early enough to give adequate warning that the system needs to be cleaned by monitoring the cathode DC voltage. With a clean system, the voltage is very steady during the etching process. As polymer starts to form, the DC voltage starts to pulsate with large pulses which increase in frequency as the polymer builds up. When this occurs, the system can be cleaned using an oxygen plasma. The cleaning process is monitored by the same technique. The voltage pulses are easily detected because they are in the order of 30 volts. The pulses can be fed to a chart recorder for visual monitoring or to a computer which provides a signal to the operator when the system needs to be cleaned.

1