Flexible interconnect of a silicon sensor at the Belle SVD

A flexible interconnect circuit(Flex) is employed for the upgraded Silicon Vertex Detector(SVD2) of the Belle experiment at the KEK b-factory. It brings signals of the Silicon Sensors to the outside of the SVD2 and makes them available for amplification at the Hybrid circuit. The required specification is rather difficult to meet. The conventional technology of a chemical etching process is stretched to the limit. We have a single-sided design as well as a double-sided design. We used a laser machine and repaired a bad spot such as a short circuit between two adjacent trace lines.