Comparison of diodes and resistors for measuring chip temperature during thermal characterization of electronic packages using thermal test chips

Thermal test chips are specially designed and built for thermal characterization of electronic packages. These chips have heaters for powering the chip and temperature sensors for measuring the chip temperature. One type of temperature sensor in wide use is a diode. Small resistors (also known as resistance temperature detectors or RTDs) are also used for measuring the chip temperature. This paper reviews and compares the characteristics of the diodes and RTDs used for chip temperature measurement during the thermal characterization of electronic packages. Techniques for reducing the measurement errors associated with these chip temperature sensors are also discussed. It is shown that the temperature versus voltage characteristics of RTDs at constant current are much more linear than those of diodes.