Research on Back-illuminated CMOS Image Sensor Irradiated by Pulsed Laser

CMOS image sensor is one of the most widely used sensors, widely used in aerospace, medical imaging, industrial detection, military reconnaissance and other fields.The laser interference and damage of CMOS image sensor has also become a research hotspot in related fields at home and abroad. To investigate the impact of pulsed laser on back-illuminated CMOS image sensors, this paper selects the Sony IMX178 back-illuminated CMOS image sensor as the target material. Based on the heat conduction equation, the finite element simulation software COMSOL Multiphysics is used to compare and calculate the temperature distribution of the CMOS image sensor under the irradiation of single-pulse lasers with different parameters.The calculation results indicate that the point damage thresholds of the sensor under the effects of single-pulse lasers at 532 nm (1 ns), 1064 nm (1 ns), 532 nm (30 ps), and 1064 nm (30 ps) are respectively 61.12 mJ/cm², 75.76 mJ/cm², 31.83 mJ/cm², and 37.43 mJ/cm².Subsequently, an experimental study on the laser irradiation effects of back-illuminated CMOS image sensors was conducted.The experimental results demonstrate that the image sensor exhibits a lower damage threshold under the influence of 532 nm pulsed lasers compared to 1064 nm pulsed lasers; picosecond pulsed lasers, with higher peak power compared to nanosecond pulsed lasers, are more prone to causing point damage; the calculated point damage thresholds are in good agreement with the experimental results.