An in situ method for measuring acid loss from polymer films

✍ Scribed by Chris Coenjarts; Jim Cameron; Gerd Pohlers; J. C. Scaiano; Anthony Zampini

• Publisher: John Wiley and Sons
• Year: 2000
• Tongue: English
• Weight: 169 KB
• Volume: 78
• Category: Article
• ISSN: 0021-8995
• DOI: 10.1002/1097-4628(20001209)78:11<1897::aid-app70>3.0.co;2-w

✦ Synopsis

This article reports an in situ approach to studying acid loss from polymer (films of the type used in microlithiography. We developed a method which makes use of the dye coumarin 6 (C6) which has absorption characteristics which change dramatically as a result of acid-induced changes in its prototropic forms. Acid loss from polymer films containing C6 is accompanied by its deprotonation, which is signaled by a change in the absorption of the film. This technique provides kinetic data describing acid loss from polymer films. Acid loss is a function of both acid volatilization from sites at the surface of the film as well as diffusional processes within the film. Under controlled conditions, acid loss obeys first-order kinetics, and the half-lives, 1/2 , of acids in phenolic and acrylate polymer films were determined. We studied the effects of temperature, acid structure, polymer structure, and T g on the 1/2 values obtained.