Radiation dosimetry for quality control of silicon wafer using electron beam

Abstract

Dosimetry studies using electron beams were performed with energies of up to 3 MeV, 2mA with various trolley speeds on the silicon wafer. The silicon wafer came with diameters of 152.4 and 203.2 mm with a thickness of 0.5 mm. The irradiations were performed by utilising the EPS 3000 Cockcroft-Walton type 3.0 MeV, 90 kwatts electron beam (EB) accelerator. Plastic film dosimeter, cellulose triacetate (CTA) was used as a dosimeter with a UV-vis spectrophotometer as the readout system. The dose setting in this investigation was ~100 kGy for 152.4 mm diameter and ~160 kGy for 203.2 mm diameter, which was based on the requirements of the customer. The acceptable dose value was set (± 10%) for better performance of the silicon wafer. It was important to comply with the international standards protocol for dosimeters in radiation processing dosimetry. The results showed that the dose and temperature decreased with increasing the speed. The optimum dose for both diameter of wafers when irradiate at electron beam current of 2 mA and the voltage of 3 MeV is at speed of 0.89 m/min. Based on these studies, it was found that it is important to control the speed of the trolley as it affects the irradiation conditions (e.g., temperature and dose measurements).