Browse Prior Art Database

Use of Doped Polymer as an Analytical Calibration Standard

IP.com Disclosure Number: IPCOM000108248D
Original Publication Date: 1992-May-01
Included in the Prior Art Database: 2005-Mar-22
Document File: 2 page(s) / 55K

Publishing Venue

IBM

Related People

Estes, SA: AUTHOR [+3]

Abstract

A method is shown for reliable preparation of a calibration standard for surface analysis instruments.

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This is the abbreviated version, containing approximately 69% of the total text.

Use of Doped Polymer as an Analytical Calibration Standard

       A method is shown for reliable preparation of a
calibration standard for surface analysis instruments.

      Analytical standards are not currently available to measure
parts per billion (ppb) levels of metallic ions on surfaces. To
accomplish this objective, ion doped polyacrylic acid films are
prepared and used to calibrate a total reflectance X-ray fluorescence
(TRXRF) instrument.

      Essential points in the process include:
           1) A polymer transparent to an analytical instruments
excitation is doped to a known concentration with suit
able elements.
           2) Polymer is deposited on a substrate to a controlled
thickness.
           3) Contamination in the polymer appears confined to
surface of substrate since polymer is transparent to instrument.
           4) Concentration of contaminant for use in calibration can
be calculated by C = B * T, where C = apparent surface
conconcentration (atoms/cm2). B = bulk concentration (atoms/cc), and
T = polymer thickness (cm).

      The new calibration method relies on two important factors:
           1) Polyacrylic acid has a low background metal count and
functions as a neutral film forming medium. Also, it has established
physical parameters and good film planarity, permitting accurate film
thickness measurement.
           2) The polymers carboxylic acid functionality act...