Quality Control Considerations for the Development of the Front End Hybrid Circuits for the CMS Outer Tracker Upgrade

Abstract

The upgrade of the CMS Outer Tracker for the HL-LHC requires the design of new double-sensor modules. They contain two high-density front end hybrid circuits, equipped with flip-chip ASICs, passives and mechanical structures. First prototype hybrids in a close-to-final form have been ordered from three manufacturers. To qualify these hybrids a test setup was built, which emulates future tracker temperature and humidity conditions, provides temporary interconnection, and implements testing features. The system was automated to minimize the testing time in view of the production phase. Failure modes, deliberately implemented in the produced hybrids, provided feedback on the system's effectiveness.

Manufacturing experience and test results of the PS prototype flexible hybrid circuit of the CMS Tracker Upgrade

“…X-ray, cross-section analysis, scanning acoustic microscopy were applied on a sampling basis at the manufacturer's premises. Visual inspection, weighing and functional testing were carried out on each delivered circuit at CERN [4].…”

“…The Panasonic 50 pin mezzanine connector and the needle probe tester were also successful to provide interconnection during the functional testing. Details of the test results can be found in [4]. The hybrid assembly was successful because the hybrid geometry followed the design specifications.…”