Browse Prior Art Database

Ozone Resist Asher Endpoint Monitoring System

IP.com Disclosure Number: IPCOM000122375D
Original Publication Date: 1991-Dec-01
Included in the Prior Art Database: 2005-Apr-04
Document File: 2 page(s) / 38K

Publishing Venue

IBM

Related People

Saitoh, T: AUTHOR

Abstract

An ozone resist asher endpoint monitoring system is disclosed which detects the concentration of ozone from the main reactive chamber to determine the finish of the resist ashing process in the ozone asher.

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Ozone Resist Asher Endpoint Monitoring System

      An ozone resist asher endpoint monitoring system is
disclosed which detects the concentration of ozone from the main
reactive chamber to determine the finish of the resist ashing process
in the ozone asher.

      Fig. 1 shows a graph of ozone (O3) concentration in the main
chamber vs resist ashing time.  The amount of ozone decreases when
the resist ashing is started for reacting ozone and resist.  When the
resist is removed, the amount of ozone increases to the amount of
supplied ozone.  This point is defined as the endpoint of resist
ashing to finish the process.

      The key of the idea is to detect the change of ozone
concentration during the ozone resist ashing reaction given by the
following formulas:
           O3  ----->  O* + O2                  ------ (1)
           CmHnOk + O*  ----->  CO2 + H2O       ------ (2)

      The ozone gas concentration can be detected by UV
absorption-type ozone monitor device 1.  The gas is sampled from the
main ozone chamber and passed through filter 2 before being supplied
to the monitor device 1 since it includes other gases such as carbon.
Measured values are sent to CPU 3 of the ozone asher, displayed and
analyzed.