Calibration of integrated CMOS hall sensors using coil-on-chip in ATE environment

Due to high demand for hall sensors mostly in the automotive and industrial applications, development and manufacturing of hall sensors in System-on-Chip (SoC) became more important. On the other hand, options for test and characterization of hall sensors in manufacturing environment are very limited. In most cases external field generators are used in order to characterize the hall sensors on a small set of production samples. In this paper, we present our Coil-on-Chip (CoC) calibration methodology where there is no need for a dedicated setup/assembly. Our methodology is also immune to self-heating. Our methodology enables reduced costs in test equipment, 100% screening of hall sensors in manufacturing tests, and reliable trimming of sensitivity spread over temperature from -40°C to 150°C. Measurement results before trimming show less than 20% six-sigma spread for normalized sensitivity across 120 samples of different hall sensor structures processed in a 0.35 μm high-voltage CMOS process.