Effect of surfactant-added developer on development of the chemically amplified photoresist

We have investigated effects of surfactant on the wettability of developer to chemically amplified resists and dissolution characteristics of the resists. The results show that surfactants enhance the wettability of developer to the resists. However, surfactant-added developer,in the case of positive resists, caused higher dissolution rate of unexposed and less exposed regions. The degree of higher dissolution rate also depends upon the molecular structure of surfactant. We have found the specific molecular structure of surfactant to improve the wettability without causing higher dissolution of unexposed and less exposed regions: Ester bonding for a tertiary butyloxycarbonyl (t-Boc) type and an acetal type of chemically amplified resist, and the alkylphenyl structure for an annealing type of resist. In the case of negative resist, the dissolution rate was not changed by addition of surfactant to developer. We have clarified that the suitable combination of surfactant and positive resist is required to utilize to the maximum the advantages of the surfactant addition, wettability improvement and volume reduction of developer.