Photoresist Exposure Control Via Continuous Dielectric Loss Monitoring of Photo-Initiated Polymerization
Original Publication Date: 1985-May-01
Included in the Prior Art Database: 2005-Feb-18
This article describes a photoexpose measurement method that continuously monitors the polymerization of photoresist by obtaining actual in situ photoresist properties. The step wedge method which was used previously had the limitations of being developer dependent, non-continuous and destructive. The dielectric loss of a photosensitive material changes with light exposure. The correlation of a given dielectric loss value and the optimum degree of crosslinking for the subsequent processing is straightforward. Simultaneous monitoring of resist photo-initiated crosslinking and light energy output from the lamp is possible. The preferred exposure tool setup is seen in the drawing. The second novel feature of this system is the contact used to measure dielectric loss.