Thermal reactions of bisazides in resists containing double bonds.

Derivatives of 2,6-bis(4-azidobenzylidene) cyclohexanone are frequently used as photosensitizers in photoresists. These compounds are generally considered to be quite thermally stable. However, there have been reports of thermal degradation occurring at temperatures as low as 60C. Experiments done here suggest that the thermal stability of the azide is adversely affected by the presence of unsaturated material in the formulation. Data from IR spectroscopy show that by itself, 2,6-bis(4-azidobenzylidene) 4-methylcyclohexanone is thermally stable in a polyamic acid film at 75-80C. However, addition of a monomeric aminoacrylate to the formulation results in a significant decay in the absorption due to the azide moiety in just a few hours at these same temperatures.