Sun-Yi Park

Novel single-layer photoresist containing cycloolefins for 193 nm

New matrix resins containing maleic anhydride and cycloolefin units for ArF excimer laser resist have been developed. Several series of these matrix resins having good dry-etching durability were prepared by free radical polymerization using AlBN as free radical initiator. All of the resists using the matrix resins revealed good coating uniformity and adhesion to silicon wafer, and were readily soluble in a variety of resist solvents such as MMP, EEP, PGMEA and EL. In preliminary 193 nm testing a resist formulated with the matrix resins sulfonium triflate as photoacid generator afforded positive images with 0.14 micrometers L/S resolution. In this paper, we will discuss the polymerization results and lithographic properties for 193 nm exposure tool.

ArF photoresist system using alicyclic polymer

We have developed a chemically amplified photoresist for use in ArF lithography based on alicyclic polymer. 3- Bicyclo(2,2,1)hept-2-yl-3-(2-methyl allyoxy)-propionic acid tert-butyl ester (BHPE) was prepared as a new kind of protected acid-labile monomer. Terpolymer, poly(BHPE-NBO-MAL), was prepared with BHPE, 5-norbornen-2-ol (NBO), and maleic anhydride (MAL) monomers by radical polymerization. Photoresist of poly(BHPE-NBO-MAL) displayed good adhesion, dry-etch resistance, and development. As a result, we obtained 0.16 micrometer line-and-space positive patterns with 2.38 wt% TMAH aqueous solution using an ArF exposure system.

Materials design and lithographic performance of maleic anhydride/cycloolefin copolymer for ArF resist

Photoresist using maleic anhydride/cycloolefin copolymer is a leading candidate for the 193 nm photolithography. Until recently, the efforts to improve 193 nm photoresist have been focused on resolution and dry-etch resistance. Therefore, we have synthesized some kinds of matrix resins and additives containing alicyclic group and acid labile group. The matrix resin is alternating copolymer obtained by free radical polymerization of maleic anhydride and cycloolefinic derivatives. And, the additives have a low molecular weight containing alicyclic group and acid labile group. The additives not only serve as dissolution inhibitors but also improve the pattern profile and dry-etch resistance. In this paper, we will describe the approaches to the resist materials, which are involved in our photoacid generator concept.