Impact of surfactant in developer on CD performance

Surfactant-formulated developers were utilized to enhance the CD performance for 365nm (I-line), 248nm (DUV) and 193nm resist processing. From one generation to the next, the resist surface becomes more and more hydrophobic, creating the need for enhanced surface wetting. Contact angle measurement of surfactant-formulated developers on different generations of resist surfaces, from 365nm to 157nm resist surfaces, indicated improved wetting. On-wafer testing showed significant improvement on CD uniformity with surfactant-formulated developers for 365nm, 248nm and 193nm processing. Faster development rates were also observed for chemically amplified resist systems, including 248nm, 193nm and 157nm.