EPR Spectroscopy of Diazoquinone–Novolac Resist Films Implanted with P+ and B+ Ions

Abstract

The nature of stable radicals in FP9120 positive photoresist films implanted with boron and phosphorus ions and deposited on the surface of single-crystal silicon wafers has been determined using the EPR technique. At an implantation fluence of 6 × 10 15 cm −2 , a narrow singlet isotropic line with a g-factor of 2.0064 is observed in the EPR spectrum. As the fluence increased to 1.2 × 10 16 cm −2 , the g-factor decreased to values close to the g-factor of the free electron. The concentration of paramagnetic centers was higher during implantation of phosphorus ions than in the samples implanted with boron ions. This difference is due to a smaller contribution of nuclear stopping during B + implantation, which does not exceed 10-15% of electronic stopping. The formation of long-lived paramagnetic centers recorded by EPR a week after implantation of positive phenol-formaldehyde photoresist is due to the presence of a powerful system of conjugated >C=O and -C=C-multiple bonds in the structure of the radicals.