Speakers
Description
"The High-Luminosity LHC (HL-LHC) will deliver instantaneous luminosities up to $7.5 \times 10^{34}~\rm{cm}^{-2}\rm{s}^{-1}$, resulting in an average of $200$ pile-up interactions per bunch crossing. This poses a serious challenge for the ATLAS detector, particularly in the forward region where detector granularity is reduced. To address this, the High-Granularity Timing Detector (HGTD) will be installed in the pseudorapidity range from $2.4$ to $4.0$, augmenting the new all-silicon Inner Tracker (ITk) with precise timing information to distinguish between collisions close in space but separated in time. Based on Low-Gain Avalanche Detector (LGAD) technology, the HGTD will comprise two double-sided layers with a readout cell size of $1.3 \times 1.3~\rm{mm}^{2}$, resulting in approximately $3.7$ million channels. The detector will provide a timing resolution of $30$ ps per track at the start of HL-LHC operations and $50$ ps at the end, enabling pile-up mitigation, correct vertex assignment, and bunch-by-bunch luminosity measurements.
The readout is based on the ALTIROC-A ASIC, a 225-channel front-end chip fabricated in a $130~\rm{nm}$ CMOS process. The large-scale production of the HGTD requires approximately $27,000$ ASICs, making wafer-level screening a critical step before dicing and module assembly.
This poster presents the wafer probing campaign for the ALTIROC-A ASIC, including the dedicated acquisition system, the testing procedure, and the results obtained for the pre-production phase. In the current campaign, $46$ wafers have been probed, achieving a high yield under the established acceptance criteria. These results are instrumental in defining robust screening rules and establishing a production-oriented framework for the large-scale quality control of ALTIROC-A ASICs."
