Process and environmental benefits with solvent-free stripping

Photoresist removal following dry etching or high-dose ion implantation conventionally employs solvents and acids, sometimes preceded by a dry oxygen-based plasma ash, These costly, hazardous, and polluting wet chemicals are then disposed of through environmentally unfriendly waste-disposal processes, often contributing to global warming, substantial energy consumption, ground water contamination, etc. A new cleaning process (ENVIRO) that dry ashes etched resist and simultaneously renders remaining material 100% DI water soluble has been qualified in manufacturing and successfully used for more than 12 months. Normalized for a 10,000 wafer-starts/week fab, this process can save more than $5 million/year in solvent costs alone.