Surface Acoustic Wave Thermogravimetric Measurements Of Thin Polymer Films

The increased use of thin film polymers in microelectronic applications has resulted in the need to better understand their chemical, thermal, mechanical, and electrical properties. Of particular interest are changes in mass and viscoelasticity during curing of new high temperature polymers. A highly sensitive technique that can monitor mass and viscoelastic changes in thin polymer films during curing to high temperature is needed. In this work a surface acoustic wave (SAW) based system was developed that was capable of measuring the mass loss due to water outgassing during cure of thin polymer films in a temperature range of 20 to 400 degrees C. It also could measure the apparent glass transition temperature of acoustically thin films, and film resonance for acoustically thick films. The principle limitations of the system are the limited accuracy of temperature compensation and the limited ability to separate mass loss effects from viscoelastic effects.