Despite the very high purity of ultrapure water used in semiconductor manufacturing, it still contains trace levels of common metals and other ions that can negatively impact wafer yield. As a result, accurate, real-time monitoring of water resistivity is critical.
As semiconductor linewidths continue to narrow and the industry moves past the 3 nm process node, the need to improve UPW quality will only grow. Resistivity sensor accuracy must continue to evolve to reliably detect very small resistivity changes on a non-zero background.
Through collaboration with industry partners, METTLER TOLEDO has developed a resistivity sensor with significantly better temperature compensation, signal stability, and environmental isolation than previously available. This increase in measurement accuracy will allow you to improve UPW quality at PoDs and PoUs, leading to greater wafer yield.
Typical resistivity sensors available today offer measurement accuracy of +/- 1%. Currently, action levels set forth by SEMI F63 fall within this acceptable error range. 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.