Browse Prior Art Database

Application of Sheet Resistance Probe to Control of Chemical Vapor Deposition Process

IP.com Disclosure Number: IPCOM000119709D
Original Publication Date: 1991-Feb-01
Included in the Prior Art Database: 2005-Apr-02
Document File: 2 page(s) / 84K

Publishing Venue

IBM

Related People

Copel, M: AUTHOR [+4]

Abstract

Disclosed is a method to monitor and control in real-time the growth rate and film thickness in a chemical vapor deposition reactor. By using a van der Pauw probe to measure the sheet resistance of a conductive film as it is being deposited, the film thickness can be monitored in-situ and used to adjust the process for optimum result.

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This is the abbreviated version, containing approximately 52% of the total text.

Application of Sheet Resistance Probe to Control of Chemical Vapor
Deposition Process

      Disclosed is a method to monitor and control in real-time
the growth rate and film thickness in a chemical vapor deposition
reactor.  By using a van der Pauw probe to measure the sheet
resistance of a conductive film as it is being deposited, the film
thickness can be monitored in-situ and used to adjust the process for
optimum result.

      A CVD reactor for the deposition of gold was modified to
include a four-point probe in the van der Pauw configuration 1,2.
Electrical contacts were placed on the front surface of a
gold-sputtered silicon wafer, at or near the wafer edge, and the four
wires were brought outside the reactor with a vacuum feedthrough.
Note that the van der Pauw configuration is not necessary for this
application; any method of measuring sheet resistance would be
suitable as long as it did not interfere with deposition.

      Other techniques which measure deposition rates are not
generally applicable to production CVD processes. Deposition rate
monitors consisting of a quartz crystal microbalance (QCM) are
commercially available.  Yet, due to their extreme sensitivity to
small changes in temperature and their vastly different surface from
the actual CVD substrate, QCMs are better suited to evaporation or
sputtering techniques where the deposition rates are more dependent
on what is occurring at the source and not at the substrate.  On a
research scale, deposition rates have been monitored by suspending
the substrate from an electrobalance 3.  However, implementation of
this scheme on a production CVD system would be extremely difficult.
Ellipsometry and light scattering techniques are sometimes used for
in-situ measurements, but they are not applicable to relatively thick
metal films.

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