Molecular Design of PAC Used for the Positive Photoresists: Optimization of M/A Value Before and After Photolysis

M/A value is introduced which is the mass ratio of compound to alkali soluble groups in the compound. The (M/A)Pb of photoactive compound (PAC) before phortolysis, the (M/A)Pa of PAC after photolysis and the Rb/a which is ratio of (M/A)pb to (M/A)Pa, are calculated, discussed and compared with NQ/M value used before. It is proved that the (M/A)pb can be interpreted as ratio of dissolution inhibition to dissolution acceleration of PAC before photolysis and the (M/A)pa is that of PAC after photolysis; the Rb/a can be ratio of dissolution inhibition to dissolution acceleration before and after photolysis essentially, and it can also be named as index of dissolution inhibition to dissolution acceleration. It is more reasonable and more reliable than using NQ/M as dissolution inhibition index to represent dissolution inhibition effect of PAC.