Evaluating Temperature Coefficient Wander in Thin Film Platinum Resistance Elements
Evaluating temperature coefficient wander in thin film platinum RTDs requires tracking substrate strain, glass passivation diffusion, and multi-point calibration.
High Temperature Soak
Stress Exposure
Thermal stress testing of electronic assemblies evaluates the reliability of materials and connections under prolonged exposure to elevated temperatures. This procedure, known as a high temperature soak, accelerates the degradation of weak interfaces before the components are deployed. It acts to identify infant mortality in semiconductor sensors.
Thermal Effect
Diffusion processes and atomic migration within the sensor elements are accelerated during the heating phase. Exposure to a high temperature soak allows any latent impurities to migrate and form stable configurations. This thermal aging stabilizes the resistor values in high-precision transducers.
Evaluation Protocol
Performance verification is conducted by measuring the electrical parameters of the device after it has been returned to room temperature. The high temperature soak is continued for a specified duration, typically several hundred hours, to simulate years of standard operational wear. Metrologists compare the post-soak resistance to the initial baseline measurements to calculate the drift rate of the instrument.
This comparison determines whether the device complies with the stability specifications required for industrial certification.
Environmental Limit
Structural integrity of the sensor housing and the insulation resistance of the lead wires can degrade if the test limits are exceeded. When the temperature is set too high, the protective coatings may melt or become conductive. This outcome invalidates the test results and can cause permanent damage to the sensor.