DO-33477/EP/ATLAS Supply of Flexible Printed Circuit Boards for the ATLAS Inner Tracker (ITk) Pixel Detector

The Contractor shall produce the flexible PCBs compliant with the design provided by CERN (see Annexes). Minor modifications to the design may be possible provided that the other requirements of this Technical Specification are respected and subject to CERN’s prior written approval. The flexible PCBs will sit on the rear (un-patterned) face of the Silicon sensor of the bare pixel module (see Figure 2). CERN will assemble the PCBs and will wire bond them to the ITkPix chip with aluminium wedge wire bonding. The flexible PCBs are designed for:  A maximum low voltage (LV) of 2 V with a maximum current of 6.8 A in the associated LV traces in the PCB,  A maximum high voltage (HV) of 650 V tested at 1.5 times (975 V), with an associated maximum current of 6.6 mA through the traces in the PCB. The PCBs support signal lines with the clock and control (160 Mb/s signals) and data lines (1.28 Gbps max signals) routed to and from the chip respectively As the PCBs each contain a large number of wire bond pads, the Contractor shall deliver the flex PCBs with ENIG metallization suitable for fine-pitch aluminium wedge wire bonding which must be free of any contamination. The flexes must be produced according to IPC and UL standards (see § 6) and meet the requirements in this Technical Specification. The Contractor shall deliver identical flex PCBs arranged into arrays of 2 × 2 PCBs.