Laser removal of positive-tone diazonaphthoquinone / novolak resist without occurring laser-induced damage to the silicon wafer

摘要

Positive-tone diazonaphthoquinone / novolak (DNQ / novolak) resist was stripped from Si wafer by using a pulsed laser beam from visible to near infrared. Silicon wafer with resist was sunk in water to utilize irradiated laser energy effectively. When the resist was irradiated with the fundamental wavelength of the Nd:YAG laser, the resist was stripped from the Si wafer. No damage could be detected from the processed silicon wafer surface. The resist stripping effect in water condition was improved due to both the thermal expansion of the Si wafer and pressure from water. And also, laser irradiation of wavelength 532 nm, having large photon energy, was found to have a higher resist stripping effect than that of wavelength 1064 nm.