Coefficient of Thermal Expansion Balancing for Field Assisted Bonding of Silicon to Glass

TL;DR

This paper presents an analytical model to optimize bonding temperature in silicon-glass anodic bonding by balancing thermal expansion coefficients, reducing stress and improving bond quality.

Contribution

It introduces a graphical method for determining the optimal bonding temperature based on thermal expansion differences, tailored for specific glass types.

Findings

Optimal bonding temperatures for Corning 7740 and LK5 glass identified.

Model effectively predicts stress levels during bonding.

Recommendations improve bonding reliability and reduce residual stress.

Abstract

Stresses caused by thermal expansion coefficients mismatch of anodically bonded glass and silicon samples are studied. An analytical model to determine graphically the optimum bonding temperature is presented. It is essentially a model for thin-film stress but uses integration of the linear coefficient of thermal expansion difference between the bonding temperature and the working temperature. Recommendations for choosing the bonding temperature of silicon to two brands of glass (Corning 7740 and LK5) are made. Keywords: anodic bonding, field assisted bonding, thermal expansion, stress.