PHOTOGENERATED ACID-CATALYZED FORMATION OF PHOSPHONIC PHOSPHORIC-ACIDS BY DEPROTECTION OF ESTERS IN POLYMER-FILMS

A new class of photodefinable polymers based on phosphonic acid esters has been developed. Photogenerated acid catalysts convert the esters to phosphonic acids in the exposed regions of films during postexposur e bake. These phosphonic acids, in addition to-providing the base solu bility necessary for positive-tone development, are also uniquely capa ble of binding metal ions and cations from solution. Preliminary litho graphic evaluations indicate that these polymers generally show high c ontrast (similar to 10), good sensitivity, low volume loss (<15%), and the potential for submicron resolution. More importantly, the pattern ed deposition of refractory metal ions has also been demonstrated, whi ch could be useful for circuit fabrication via at-the-surface imaging schemes.