Lithography Track Thermal Metrology Update

Staff -- Semiconductor International, 4/1/1998

The February Semiconductor International article "Track Systems Meet Throughput and Productivity Challenges" discussed technology from SensArray Corp. (Santa Clara, Calif.) that was used for measuring hot plate temperature uniformity. The company has more advanced technology available than that described in the article: the Process Prober 1840. The 1840 is designed specifically for thermal metrology on lithography tracks and allows qualification of hot plates to temperatures <0.3Å. Wafers are instrumented with up to 31 embedded platinum resistance temperature detectors (RTDs), which provide superior accuracy over thermocouples. The RTDs are calibrated to a precision of .05Å and an absolute accuracy of .1Å. The design uses a flat cable feedthrough to allow installation on various hot plate and cover designs without equipment modifications.