Synthesis of polymers with a norbornane backbone by radical copolymerization of alkyl 2-norbornene-2-carboxylates for photoresist applications

Abstract

The radical copolymerization of alkyl 2-norbornene-2-carboxylates, 1a-c, with alkyl (meth)acrylates, to produce copolymers with norbornane in the main chain, is described here. g-Butyrolactone-and hydroxy group-containing norbornene-based monomers (1b and 1c, respectively) were freshly synthesized, and their radical copolymerization behavior with n-butyl acrylate was examined. Methyl 2-norbornene-2-carboxylate, 1a, and the new monomers, 1b and 1c, were employed as comonomers for radical terpolymerization with lactone-and adamantane-containing (meth)acrylates to produce copolymers that could be applied as new, more chemically robust 193-nm photoresist materials. The dissolution rate of the spin-coated copolymer films after exposure to a photoacid generator, a significant characteristic in the photoresist application, was measured for various exposure doses of 193-nm ArF laser light under standard conditions in an aqueous alkaline solution.

Radical copolymerization of alkyl cyclobutenecarboxylates fused with cycloaliphatic framework with alkyl (meth)acrylates

“…Although the copolymerization of the alkyl cyclobutenecarboxylates with MMA did not afford well‐defined copolymers, copolymerization with alkyl methacrylates having ester‐substituents larger than Me gave copolymers efficiently. In particular, with a prospect for photoresist applications in the near future, we examined terpolymerization of 4‐6 a and a mixture of 7‐9 a with γ‐BL and adamantane‐containing methacrylates ( 10 and 11 ) . (Scheme ) In contrast to the copolymerization of these cyclobutenecarboxylate monomers with MMA, the terpolymerization with these methacrylates with bulky ester groups proceeded efficiently, giving terpolymers exhibiting only one distinctive T g .…”

“…2‐Methoxyethyl propiolate 2 was prepared via Mitsunobu esterification of propiolic acid with 2‐methoxyethanol. Preparation of 3‐γ‐butyrolactonyl propiolate 3 was reported in our previous publication …”

“…Meanwhile, we have recently reported that alkyl 2‐norbornenecarboxylate can be radically copolymerized with alkyl acrylate, affording polymers having norbornane framework in the polymer backbone . We have also demonstrated that the thus obtained norbornane‐containing copolymers are promising candidates for 193 nm photoresist applications by revealing dissolution rate vs. exposure dose relationship of some copolymers of alkyl 2‐norbornenecarboxylate with alkyl (meth)acrylates . Interesting to note with respect to the reactivity of the norbornenecarboxylates is that because alkyl cyclopentenecarboxylate does not possess polymerizability, ethylene‐fused structure in the norbornene framework can be considered to sterically enhance the reactivity of the monomer.…”

Polymerization of 8-ACETOXYTETRACYCLO[4.4.12,5.17,10.01,6]DODEC-3-ENE and Its Copolymerization With Acrylic Acids

“…The development of simple methods for the synthesis of alicyclic monomers of various functionality, as well as methods for their polymerization and copolymerization to obtain polymeric materials with a wide range of applications is one of the challenges facing the chemistry of macromolecular compounds [1][2][3][4][5][6][7].…”

“…This article presents the results of studies on radical polymerization of 8-acetoxytetracyclo[4.4.1 2,5 .1 7,10 .01.6]dodec-3-ene (ATCD) and its copolymerization with (meth)acrylic acids in the presence of BF 3 •OEt 2 .…”