Ultra-high Accuracy, Fast Response Thermistor and Transmitter for Controlling Photolithography Tool Temperature or Clean Room Temperature
Precise measurements are required in the photolithography portion of processing wafers. During the numerous times when a given wafer is in a photolithography tool for subsequent layers of the circuit to be patterned, a change in temperature of more that +/- 1 degree will cause alignment defects that could significantly reduce the yield on the wafer.
The high power lamp used in the photolithography process generates a lot of heat inside the tool.
This heat must be monitored and balanced with the right amount of cooling air to keep the tool interior and wafers at a constant temperature. The PDT-440 thermistor transmitter, or the PDT-444 high accuracy 4-wire transmitter can be used in conjunction with a high-stability, fast-response thermistor to monitor and control these air flows. With the PDT-444, control to +/- 0.01C is possible.