Photochemical free‐volume generation in poly(methyl methacrylate) photoresists

The dissolution rates of poly(methyl methacrylate) [PMMA] thin films on quartz substrates are studied by a combination of laser interferometry and fluorescence quenching methods. In this way one can monitor the penetration, rate of the solvent (2‐butanone, 2‐pentanone) into the film. When these films were prepared containing 2 to 8 percent Meldrum's diazo (1) as a dopant, the dopant acted as a mild retarder of film dissolution. Upon irradiation at 254 nm, 1 is converted to CO, N2 + acetone, and this process leads to a pronounced acceleration' of the PMMA film dissolution rate. Copyright © 1989 Society of Plastics Engineers