Development of infrared absorption-based flow sensor for in-situ measurement of dispenser discharge amount

Abstract

During the electronic packaging process, blockage of a dispenser nozzle or epoxy hardening in the nozzle causes discharging problems. An infrared-absorption-based flow sensor that quantitatively measures the discharge from dispensers used for electronic packaging is developed to solve this problem. A local spot of the epoxy-supplying tube is heated using a laser to make a thermally tagged epoxy. Its velocity and discharge time are measured using light-emitting diode and photodetector pairs to measure quantitative discharge. On comparing the quantitative discharge obtained by the developed sensor and that determined by an electronic scale, a maximum deviation of 0.8% was observed, with a maximum uncertainty of 2.9%. Therefore, it is confirmed for the first time that the developed infrared absorption-based sensor can accurately measure the discharge amount of the dispenser in situ. In fact, the sensor can monitor the discharge amount during the dispensing process and be used as a feedback sensor for the precise control of the discharge amount.