Deblocking reaction of chemically amplified positive DUV resists

Abstract

Deblocking reaction mechanisms and lithographic performance in chemically amplified positive ArF resists were investigated by analyzing acid concentration and blocking levels. The resists consisted of poly(carboxytetracyclododecyl methacrylate50-co-ethoxyethylcarboxytetracyclododecyl methacrylate50), poly(earboxytetracyclododecyl methacrylate70-co-tetrahydropyranylcarboxytetracyclododecyl methacrylate30), or poly(tricyclodecylacrylatego-60-tetrahydropyranylrnethacrylate- 20-co-methacrylic acidj20), and triphenylsulfonium triflate as a photo acid generator. The deblocking reaction mechanisms were evaluated from Arrhenius plots of the deblocking reaction rate constant. It was found that the deblocking reaction of all resists is ruled by two rate-determining steps - a reaction-controlled step in the low-temperature region and an acid-diffusion-controlled step in the high-temperature region. Furthermore, the relationship between deblocking reaction and lithographic performance, especially post exposure delay (PED) stability was investigated. As a result, it has been concluded that small acid loss induces better FED stability. ©1999TAPJ.