Dissolution behavior of alicyclic polymers designed for ArF excimer laser lithography

We have analyzed the dissolution rate of alicyclic polymer resists designed for ArF excimer laser lithography with an in-house laser dissolution rate monitor. The analyzed polymers were methacrylate terpolymer with a tricyclodecanyl group and carboxy-tricyclodecanylmethyl methacrylate copolymer which has a polar carboxylic acid in alicyclic groups. We found that the alicyclic polymer dissolution rate was affected very little by developing conditions such as developer concentration or kind of developer. Furthermore, when we measure the dissolution rate as a function of the polar molecule content, we found that the dissolution rate of the alicyclic polymer is similar to that of conventional polyvinylphenol (PVP) polymers. We also demonstrate that the polymer dissolution rate can be predicted from the percolation theory for both conventional PVP polymer and alicyclic polymers. Moreover, the percolation theory can be applied to chemically amplified positive resists while taking the contribution of the protective group to polarity into consideration. These findings should be very useful for theoretical resist design and material development.