Development of the hybrid structure for the barrel module of the ATLAS silicon-microstrip tracker

A novel hybrid structure for the barrel module of the ATLAS semiconductor tracker (SCT) is developed. The hybrid carries 12 bare readout chips totaling 1536 channels. A flexible copper-polyimide four-layer lamination is used as a basic circuit. The circuit is reinforced by two carbon-carbon bridges coated with Parylene polymer. The hybrid staffed by resistors, capacitors, and pitch-adaptors undergoes heat cycling and quality inspections. The hybrid after chip mounting and wire bonding is placed over the top and bottom sides of the module assembly with no direct contact to silicon sensors. The electrical, mechanical, as well as thermal performances of the module are proven to be excellent.