Low energy (<60 keV) X-ray sources are currently used for total dose tests of unpackaged semiconductor devices and circuits due to the higher dose rates (100-1000 rad(Si)/s), lower cost and radioprotection constraints than 60Co g-ray sources.

The X-ray facility installed at the INFN National Laboratory of Legnaro is the Seifert RP-149 Semiconductor Irradiation System equipped with a standard tube for X-ray diffraction analysis: maximum power 3000 W, maximum voltage 60 kV, tungsten anode, 0.3 mm Be inherent filtration, take off angle 6 degree.


Fig.1. The X-ray irradiation facility.


The tube is located inside a shielding cabinet and it can be moved with an accuracy of 30 mm along the x-, y- (motorized) and z- (manual) axis of 15 cm, 20 cm and 450 cm, respectively, over a commercial semiautomatic probe station for total dose tests at wafer level. The tube voltage and current can be set with kV and mA resolution, respectively.