NIST logo

Publication Citation: Effect of Copolymer Composition on Acid Catalyzed Deprotection Reaction Kinetics in Model Photoresists

NIST Authors in Bold

Author(s): Shuhui Kang; Vivek M. Prabhu; B D. Vogt; Eric K. Lin; Wen-Li Wu; Karen Turnquest;
Title: Effect of Copolymer Composition on Acid Catalyzed Deprotection Reaction Kinetics in Model Photoresists
Published: June 25, 2006
Abstract: The kinetics of an acid-catalyzed deprotection reaction in model photoresist materials was studied as a function of copolymer composition with Fourier Transform Infrared spectroscopy. A mathematical model was developed to analyze the acid catalyzed deprotection kinetics with respect to coupled reaction rate and acid-diffusion processes. The first order reaction rate constant decreases as a non-reactive comonomer content is increased. Additionally, the extent of reaction appears self-limiting as verified by a slowing down necessitating an acid-trapping chemical equation to model the data. This composition-dependent reaction constant indicates a strong interaction of the acid with the increasing polar resist matrix that drastically reduces the acid transport rate. The severely reduced acid transport is consistent with hydrogen bonding between photoacid and methacrylic acid product. These results demonstrate a correlation between polymer microstructure and acid catalyzed kinetics.
Citation: Polymer
Volume: 47
Pages: pp. 6293 - 6302
Keywords: copolymer;diffusion;FTIR;outgassing;photoacid;photolithography;photoresists;reaction rate constant
Research Areas: Polymers
PDF version: PDF Document Click here to retrieve PDF version of paper (513KB)