The effect of ultrasonic agitation on the stripping of photoresist using supercritical CO2 and co-solvent formulation

A novel technology for removing high-dose ion-implanted photoresist (HDI PR) from semiconductor wafers using supercritical carbon dioxide (scCO2) and several co-solvent formulations have been described. A combination of ultrasonic agitation with scCO2/co-solvent stripping was found to be an effective method for photoresist removal. Ultrasonic agitation was an efficient technique for achieving higher stripping rates. The effects of temperature, pressure, reaction time and the type of organic co-solvent on the stripping rate of HDI PR were investigated. The microstructures of sample wafers after stripping were characterized by scanning electron microscopy and energy dispersive X-ray spectrometer.