Process for producing film forming resins for photoresist compositions

• Main Authors: Rahman, M. Dalil, McKenzie, Douglas, Kudo, Takanori, Padmanaban, Munirathna
• Format: Patent
• Language: English
• Published: 26.08.2003

The present invention provides a process for producing a film forming resin suitable for use in photoresist compositions. The process involves removing metal ion impurities from such a film forming resin by passing a film forming resin having metal ion impurities through one or more filter sheets as described hereinbelow. One of the filter sheets comprising a self-supported fibrous matrix having immobilized therein a particulate filter aid and a particulate ion exchange resin. The other filter sheet comprises a self supporting matrix of fibers, such as cellulose fibers, having immobilized therein a particulate filter aid and binder resin, and preferably not containing any ion exchange resin embedded therein. The present invention provides a method for producing a film forming resin suitable for use in a photoresist composition, involving the following steps: (a) providing a solution of a film forming resin in a solvent; (b) providing the following two filter sheets: (i) a filter sheet containing a self-supporting fibrous matrix having immobilized therein a particulate filter aid and particulate ion exchange resin particles, where the particulate filter aid and ion exchange resin particles are distributed substantially uniformly throughout a cross-section of said matrix; and (ii) a filter sheet containing a self-supporting matrix of fibers having immobilized therein particulate filter aid and binder resin; (c) rinsing the filter sheets of step (b) with the solvent of step (a); and (d) passing the solution of the film forming resin through the rinsed filter sheets of step (c).