Silicon Substrate Thermal Expansion Mechanics in Inertial Sensors
Substrate thermal expansion creates packaging shear stress that warps MEMS proof masses, demanding central single-anchor isolation and polynomial offset calibration.
Factory Thermal Calibration
Adjustment Procedure
Systematic correction of sensor output against a temperature reference happens during the manufacturing phase. A factory thermal calibration ensures that every unit produced meets the accuracy specifications stated in the datasheet. Technicians subject the devices to multiple temperature setpoints within a controlled oven.
Hardware Implementation
Non-volatile memory stores the resulting coefficients for use by the internal processor. During factory thermal calibration, the system records the raw output of the sensing element alongside the readings from a high-precision platinum resistance thermometer.
Reference Standard
Metrological traceability links the factory instruments to national laboratory standards. Validation of the factory thermal calibration involves testing a statistical sample of the production lot after the coefficients have been programmed.
Performance Outcome
Users receive a device that provides corrected readings without needing further field adjustment. The factory thermal calibration accounts for unit-to-unit variations in sensitivity and offset. Drift over time may eventually require the device to return for a periodic recalibration to maintain its rated precision.
Automated test stands execute this process by cycling through the full operating range while the devices under test communicate with a central server. This server calculates the polynomial fit and uploads the unique correction map to each device. Verification is successful when the residual error falls within the specified tolerance band.