Silicon glass anodic bonding under partial vacuum conditions: problems and solutions

摘要

Single and dual phase procedures are developed for bonding silicon and 7740 Pyrex wafers in nitrogen at the atmospheric pressure and under partial vacuum. Their efficiencies are evaluated by comparison of the atomic bond populations. It is shown that at 10(5) Pa, 200 V and 500 degreesC almost optimum populations are obtained. Under vacuum, less dense populations and less uniform distributions are formed. The use of an aluminium layer deposited on the Pyrex surface in contact with the heating plate and the silicon heating by an electric lamp improve significantly the population characteristics. At 100 Pa, these modifications limit the decrease in the minimum bond density to 22% if the potential difference equals 250 V and to 13% at 750 V. The addition of an in situ treatment at the atmospheric pressure reduces the difference to 4% and yields almost optimum bond populations. (C) 2002 Elsevier Science B.V. All rights reserved. [References: 12]