HDI flexible front-end hybrid prototype for the PS module of the CMS tracker upgrade

Abstract

The CMS tracker upgrade for the HL-LHC relies on different module types, depending on the position of the respective module. They are built with high-density interconnection flexible circuits that are wire bonded to silicon strip and pixel-strip sensors. The Front-End hybrids will contain several flip-chip bonded readout ASICs that are still under development. Mock-up prototypes are used to qualify the advanced flexible circuit technology and the parameters of the hybrids. This paper presents the Pixel-Strip (PS) mock-up hybrid in terms of testing, interconnection, fold-over, thermal properties and layout feasibility. Plans for circuit testing at operating temperature (-30°C) are also presented. K: Front-end electronics for detector readout; Radiation-hard electronics; Detector design and construction technologies and materials; Manufacturing

Front-end hybrid designs for the CMS Phase-2 Upgrade towards the production phase

“…This was due to the late availability of the front-end readout chips, the Short Strip ASIC (SSA) and MPA ASICs that were required for the development. In order to try the different circuit construction (full size fold-over with CIC ASIC) a mock-up circuit (PS-MCK) was designed with various test features, but with the CBC2 ASICs [4,5]. These test features allowed to collect information about the functionality of the antenna tester, the differential impedance, the thermal conductivity of the circuits, the CF lamination process and the folding procedure.…”

Integration and Packaging

“…The size and complexity of substrates (flex, PC board, ceramic) for HEP applications has become a significant limitation on detector design. We often use multi-chip modules to extract signals from front-end sensors, process them and send the resulting signals to the readout [15]. Replacing conventional hybrid circuits with silicon-based "2.5D" substrates can improve the bandwidth, density and power efficiency of these systems.…”

Testing of the front-end hybrid circuits for the CMS Tracker upgrade

“…Another hybrid being produced (later referred to as PS prototype hybrid) contains two CBC2 ASICs and implements deliberately built-in failure modes. This PS prototype hybrid will be used as a validation platform for the test setup and proposed testing methods [6].…”

“…A further development of this method is the direct implementation of the antenna in the hybrid. The upcoming PS prototype hybrid will include this feature [6].…”