Isolating Micro-Machined Die Packaging Stress during Automated Thermal Calibration
Automated thermal calibration must isolate packaging thermo-mechanical stress shifts from intrinsic silicon sensor signals using real-time compensation.
Automated Thermal Calibration
Adjustment Routine
Programmed thermal cycles manage the correlation between raw sensor outputs and reference standards. This automated thermal calibration utilizes digital interfaces to record data across a specified operating range. The process yields a set of coefficients stored in non-volatile memory.
Execution Mechanism
Hardware controllers drive the ramp and soak cycles while a master thermometer provides the truth value for every setpoint. Logic inside the test system monitors for thermal stability before capturing the digitized signal from the unit under test. Once the system detects a steady state, it triggers the data acquisition sequence and moves to the next temperature node.
Error Source
Variations in the thermal mass of the test fixture create lags between the reference probe and the internal junction of the device. Heat sinking through the contact pins or convection currents inside the oven chamber often introduces a measurement offset. These gradients represent the primary uncertainty in the final correction curve.
System Validation
Verification occurs by comparing the calibrated output against an independent secondary standard at points not used during the initial fitting. Residual errors at these check points determine if the device meets its accuracy specification. A successful validation confirms the mathematical model correctly interpolates between the discrete points of the automated thermal calibration run.