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Browse Prior Art Database

Film Thickness Photometer System

IP.com Disclosure Number: IPCOM000121084D
Original Publication Date: 1991-Jul-01
Included in the Prior Art Database: 2005-Apr-03
Document File: 2 page(s) / 74K

Publishing Venue

IBM

Related People

Ormond, DW: AUTHOR [+2]

Abstract

A photometer system is disclosed that quickly and accurately determines the thickness of semi-transparent films. Calibration curves are established correlating film thickness (measured independently by X-ray fluorescence) and optical density of the specimen, as measured by the photometer system. By measuring the percent transmission of light through a film of unknown thickness, calibration data is referenced to determine the thickness of the film.

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This is the abbreviated version, containing approximately 57% of the total text.

Film Thickness Photometer System

      A photometer system is disclosed that quickly and
accurately determines the thickness of semi-transparent films.
Calibration curves are established correlating film thickness
(measured independently by X-ray fluorescence) and optical density of
the specimen, as measured by the photometer system.  By measuring the
percent transmission of light through a film of unknown thickness,
calibration data is referenced to determine the thickness of the
film.

      Broadband visible light is used since metallic films have no
sharp absorption bands in the visible region.  The films are
deposited on clear, quartz glass discs.  The photometer procedure is
started by placing a clear quartz glass disc into the holder and
measuring I, intensity of the light without any film.  With the
photometer meter scale set, the light intensity is adjusted for full
scale reading, 100 (equal to I).  Now percent transmission can be
read directly from the meter reading.  A quartz disc with the film of
unknown thickness is measured by the photometer to give, X, percent
transmission of the film.  This value X is then checked with
calibration data to determine the film thickness.

      Evaporated and sputter deposited, pure semi-transparent thin
films have been measured quickly, inexpensively and at the point of
fabrication for real time process control by this photometer system.
Pure chromium films, 100 and 350 Angstroms in thickness, have been
moni...