The Polymer and Colloids Group
In the microelectronics industry, the resolution and contrast obtained from exposure and processing of photoresists determines the density of active centers in a microelectronic device. When regions of the film are removed by selective dissolution, the ultimate resolution obtainable can be affected by polymer swelling at the film-solvent interface. With B. A. Smith at the IBM Almaden Research Labs, we developed a method based upon simultaneous fluorescence quenching and laser interferometry measurements for following the dissolution process, and were successful in determining the thickness (50 to 90 nm) of the swollen gel layer at the interface between glassy PMMA and organic solvents. [J. Phys. Chem., 96, 7462-7465 (1992)]