As regulators place ever greater emphasis on sustainability, semi fabs are under growing pressure to increase the quality and decrease the quantity of water in waste streams. As the primary indicator of water quality, accurate resistivity measurement is crucial.
RCA cleaning is used between each step of wafer production and utilizes three or four cleaning baths, each followed by an ultrapure water (UPW) rinse to remove chemicals, residues, and particles before the next production step.
Typical resistivity sensors available today offer measurement accuracy of +/- 1%. This level of uncertainty may be acceptable for some processes, but it does not help semi fabs meet their needs for the production of next-generation technologies. To address these evolving requirements, METTLER TOLEDO Thornton has developed the UPW UniCond™ resistivity sensor - the only available resistivity sensor capable of achieving ≥0.5% accuracy on a temperature-compensated resistivity measurement.
For RCA cleaning, this improvement in measurement accuracy will help users:
- Increase wafer yield by tightening incoming water quality specifications without action levels falling within the error of the sensor.
- Confidently make faster decisions on rinse-to-resistivity to improve throughput.
- Make earlier determinations on where to divert waste streams, maximizing water for reclaim/reuse, and minimizing water sent to discharge.