Browse Prior Art Database

Endpoint Technique for Chemical-Mechanical Polish

IP.com Disclosure Number: IPCOM000101162D
Original Publication Date: 1990-Jul-01
Included in the Prior Art Database: 2005-Mar-16
Document File: 2 page(s) / 61K

Publishing Venue

IBM

Related People

Warnock, JD: AUTHOR

Abstract

Disclosed is a technique for monitoring the chemical-mechanical polish process and determining when the desired end-point has been reached. This technique provides a practical way of monitoring the process in real-time, thereby improving process control and yield.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 65% of the total text.

Endpoint Technique for Chemical-Mechanical Polish

       Disclosed is a technique for monitoring the
chemical-mechanical polish process and determining when the desired
end-point has been reached.  This technique provides a practical way
of monitoring the process in real-time, thereby improving process
control and yield.

      During the chemical-mechanical polishing process, the friction
between the polishing pad and the wafer tends to heat the pad,
increasing its temperature by a noticeable amount.  If the
temperature of the underlying table is constant, the increase in
temperature of the polishing pad depends only on the friction between
the wafer and the pad and the velocity of the wafer with respect to
the pad.  This friction will change as a given film is polished off
the wafer surface, providing that the underlying material (whether it
is the substrate silicon or another film) has a different coefficient
of polishing friction.  This change in friction translates into a
temperature change of the pad which can be detected and translated
into an endpoint signal using the method described below.  This
technique is very general and will work for any polishing process in
which one film is removed from over another film with different
polishing friction.

      A remote infrared sensing thermometer monitors the temperature
of the pad surface.  A small computer continuously samples the analog
output of the thermometer. Signal processing by the computer
el...