Production process of copolymer for semiconductor lithography

Abstract

Efficient and reproducible production of a copolymer for lithography, which has stable quality, with little lot-to-lot variations, and is suited for film-forming and coating compositions. Radical polymerization of a monomer, which contains at least one ethylenic double bond, with an initiator, in a solvent, and purification of the reaction mixture by precipitation and filtration, in a hermetically-closable single vessel divided by a filter medium, into a first section provided with fluid feeding means and agitating means, and a second section with fluid drawing means. Feeding the reaction mixture from the fluid feeding means into the first section of the vessel, containing a poor solvent, and contacting the reaction mixture with the poor solvent to precipitate a solid; and filtering the resulting fluid, containing the precipitated solid, through the filter medium, drawing the resultant filtrate through the fluid drawing means, and then separating the precipitated solid.