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Analytical Determination of Silicon in Vapor Deposited Cu Al Si Overlay Films

IP.com Disclosure Number: IPCOM000088658D
Original Publication Date: 1977-Jul-01
Included in the Prior Art Database: 2005-Mar-04
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Hoffmeister, W: AUTHOR [+3]

Abstract

Silicon vapor deposited on top of Cu-Al films is generally determined by X-ray fluorescence (XRF) measuring the SiK proportional to intensity. When the substrates are at elevated temperatures during evaporation, a correction is required because of Si migration into the Cu-Al film. The weak SiK proportional to radiation leads to significant absorption. Deviations in temperature, which are higher at elevated temperatures (>/= 200 degrees C), additionally falsify the results.

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Analytical Determination of Silicon in Vapor Deposited Cu Al Si Overlay Films

Silicon vapor deposited on top of Cu-Al films is generally determined by X- ray fluorescence (XRF) measuring the SiK proportional to intensity. When the substrates are at elevated temperatures during evaporation, a correction is required because of Si migration into the Cu-Al film. The weak SiK proportional to radiation leads to significant absorption. Deviations in temperature, which are higher at elevated temperatures (>/= 200 degrees C), additionally falsify the results.

The error resulting from migration is overcome by using a correction factor. This factor is obtained as follows. The Cu-Al-Si overlay evaporation is performed on an Al foil having the same elevated temperature as the Si wafers. This foil is subjected to XRF analysis. Its SiK proportional to intensity is compared with the SiK proportional to intensities of a foil evaporated at room temperature.

A factor of 1.14 (which is the quotient of both intensities) is obtained for temperatures of about 200 degrees C. To compensate changing substrate temperatures, the foil used in the high temperature evaporation process is fixed to a gold-coated quartz substrate which acts as a heat reservoir.

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