193-nm photoresist development at Union Chemical Labs., ITRI

Abstract

Union Chemical Laboratories has designed and synthesized novel copolymers of norbornene-alt-derivatives, maleic anhydride and alicyclic acrylate for ArF excimer laser lithography. These polymers are prepared using a free-radical copolymerization process. Applying the resin for 193-nm single layer chemically amplified photoresist composed of cholate derivative with a PAG leads to a good resolution below 0.13 micrometer line/space patterns using an ArF stepper and 2.38 wt% tetramethylammonium hydroxide aqueous solution as a developer. Furthermore, alternating phase shift mask was used in combination with a feature size as small as 0.1 micrometer. To overcome post exposure delay (PED) effect caused by airborne contamination, three new base additives were used in the resist formulation. The etching-resist ability of resists by reaction ion etching (RIE) was showed better than conventional g-line and KrF excimer laser resists. Experimental results of CHF<SUB>3</SUB>/CF<SUB>4</SUB> as etch gas, indicate that the etching rate selectivity with respect to SiO<SUB>2</SUB> is about 0.5. The UCL photoresists also showed good shelf life stability.