Patent ID: 6043002
Filing Date: 2000-03-28
Classification: C08G,G03F

Abstract:
A method for producing a positive photoresist composition comprising:a) washing an anion exchange resin with water, followed by washing with a mineral acid solution, washing again with water, followed by washing with an ammonium hydroxide solution, followed by washing again with deionized water, and thereby reducing the level of sodium and iron ions in the anion exchange resin to less than 200 ppb each;b) preparing a solution of a novolak resin in a suitable novolak resin solvent;c) washing the anion exchange resin with a solvent which is the same as, or at least compatible with, the novolak resin solvent, to remove substantially all of the water; d) passing the solution of novolak resin through the washed anion exchange resin from step c) at a flow rate such that the residence time is more than 20 minutes, and thereby reducing the level of sodium and iron ions in the solution to less than 100 ppb each; ande) producing a photoresist composition by providing an admixture of; 1) a photosensitive component in an amount sufficient to photosensitize the photoresist composition; 2) the novolak resin from step d) and 3) a suitable photoresist solvent.