Controlling the Dissolution Behavior of (Meth)acrylate-Based Photoresist Polymers in Tetramethylammonium Hydroxide by...

(Meth)acrylate polymers are commonly used as photoresist materials in photolithography. However, these polymers encounter the problem of swelling during the development process. To address this, we explored the use of a hydrophobic group to control the solubility in the hydrophilic developer. In this study, we synthesized two types of polymers to evaluate the impact of the developer on (meth)acrylate polymers for photoresist applications. Adamantyl methacrylate (AdMA) was selected as the hydrophobic group, while 2-ethoxyethyl acrylate (2-EEA) served as the hydrophilic group, enabling the synthesis of both hydrophilic and hydrophobic polymers. Our goal was to assess how the presence of adamantyl monomers influenced the solubility of the polymer. This study demonstrated that solubility was primarily influenced by functional groups, particularly hydrophobic groups, rather than other factors. Polymers with more than 50% hydrophobic groups can be effectively controlled for their solubility in TMAH. These findings show that the solubility of photoresist polymers in TMAH can be tuned by incorporating a high proportion of hydrophobic groups. The study further confirms the role of adamantyl monomers as effective hydrophobic (aliphatic) groups in modulating the solubility of (meth)acrylate polymers in developer solutions.