First results on the final readout chip for the High-Luminosity LHC upgrade of the CMS Inner Tracker

• Published in: Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment Vol. 1068; p. 169736
• Main Authors: Grippo, Michael, Bartosik, Nazar, Demaria, Natale, Luongo, Fabio
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.11.2024
• Subjects: CMS; High luminosity LHC; Inner tracker; Readout electronics; Wafer-level testing; CMS; High luminosity LHC; Readout electronics; Inner tracker; Wafer-level testing
• ISSN: 0168-9002
• DOI: 10.1016/j.nima.2024.169736

The CMS Readout Chip (CROC) is a 65nm CMOS hybrid pixel readout chip for the High-Luminosity LHC upgrade of the CMS Inner Tracker. The chip has been developed by the CERN RD53 Collaboration in order to withstand radiation doses up to 10MGy and hit rates up to 3GHzcm−2 on the innermost tracking layer. Moreover, it must handle an increased sensor granularity (pixel size of 2500µm2) with respect to current detectors and operate at detection thresholds as low as 1000e. Twenty wafers of the prototype chip (CROCv1) have been produced in 2021. The CROCv1 characterisation and verification campaign has, overall, demonstrated the radiation resistance of the chip and its performance. The production version of the chip (CROCv2) was submitted in October 2023 and the engineering run wafers have been received in January 2024. In this contribution, the first results from CROCv2 wafer-level testing of more than 1900 chips from the engineering run will be outlined.