High-pitch metal-on-glass technology for pad pitch adaptation between detectors and readout electronics

Abstract

Modern High Energy Physics and Astrophysics strip detectors have increased channel density to levels in which their connection with the readout electronics has become very troublesome due to high pad pitch. Also, direct wire bonding is prevented by the fact that typically detector's pad pitch and electronics' pad pitch do not agree. A high pitch metal-on-glass technology is presented, that allows pad pitch adaptation between detectors and readout electronics. It consists of high density metal lines on top of an insulating glass substrate. A photoresist layer is deposited covering the metal tracks for passivation and protection The technology is tested for conductivity, bondability, bonding pull force, peel of, and radiation hardness, and it is an established technology in the clean room of the CNM Institute in Barcelona. This technology has been chosen by the ATLAS Collaboration for the pad pitch adapters of the SCT Endcap Modules, by the Compton Camera Collaboration, and by other REP experiments for the interconnection between detectors and readout electronics.