Implementation on 3D surface algorithm for measuring thickness parameter of sensor chip

A large hadron collider is operated by CERN to conduct a large scale and a long term particle physic experiment, namely ALICE. Thousand of sensors are used in the collider sensor system to track the trajectories of the results of particle collisions. 3D surface measurement is proposed to assess the quality of sensors. Some surface characteristics of the sensors are defined based on the quality requirements. The 3D imaging algorithm has been developed to measure the thickness of connection line and edge of surface pads. A 3D scanner based on structure light projection method is used to scan the chip surfaces. The algorithm is tested on sensor models which have size similar with the actual sensor chip. The thickness of the line connection is found to be 0.0069 ± 4.0957 × 10^-4 mm whereas the pad edge is 0.0015 ± 13.2570 × 10^-4 mm. The results show that the algorithm can provide consistent measurement for both parameters.