Spike Thermocouples and Torch Thermocouples

Spike thermocouples and torch thermocouples are installed outside of the furnace process environment to directly measure the temperature of external heaters or furnace torch. Spike thermocouple readings are compared to the readings of the profile thermocouple that is inside the furnace chamber so that an offset may be determined between the heater temperature and the corresponding wafer temperature.

Single Spike Thermocouple vs Dual Spike Thermocouple

Spike thermocouples may be ordered as single or dual (two measuring junctions). Dual spike thermocouples are often used as a redundant measurement incase one circuit fails. Dual spike thermocouples may also be used to track sensor drift. This is accomplished by populating one of the dual circuits with a different calibration wire (typically R, S or B) than the other circuit. As the thermocouple circuits age, they will drift. Different calibrations will drift at different rates. Comparing the rate of drift differential will give an indication as to the amount of drift the particular dual spike thermocouples is seeing, and by extension, the rate of drift for the other spike thermocouples. Spike thermocouple recalibration or replacement decisions may be made based on objective criterion rather than arbitrary time-based maintenance schedules.

Single Spike

Dual Spike

Spike Thermocouple Tips

Slot Tip

Chisel Tip

V-Grove Tip