Thermal decomposition of dissolution inhibitor in chemically amplified resist during prebake process

The equation which represents the decomposition mechanism for two dissolution inhibitors in a chemically amplified positive resist consisting of polyvinylphenol protected with p-t-butoxycarbonylmethyl (BCM-PVP) and p-t-butoxycarbonyl (BOC-PVP) groups was investigated by isothermal thermogravimetry (TG) analysis. The reaction orders of these polymers were different and this difference was caused by the difference in the thermal deprotection reaction of the protecting group. It was shown that the decomposition of BCM-PVP is promoted as decomposition proceeds, which is expressed by the equation. This result indicates that, when BCM-PVP is used as an inhibitor in chemically amplified resists, it is important to determine the baking temperature and duration in order to prevent its decomposition.