Stave Module Status Tony Affolder The University of Liverpool On behalf of cast of thousands… ATLAS Upgrade Week November 10,

Stave Module Requirements 4 ATLAS Upgrade Week November 10, 2010 Design is driven by minimising material  Hybrid is substrate-less with no connectors  Glued directly on to the sensor  Use of minimal glue layers for both ASIC and hybrid attachment  Improves thermal paths and again reduces material  Layout optimised for stave and serial powering (parallel and DC-DC optional)  Control of M-shunt scheme serial powering built into hybrid with discrete components Optimized for mass production methods as well (future build will require >10000 circuits)  Yield and reliability of flex circuits taken into account from the beginning  Designed to enable mass wire bonding, component attachment and testing of circuits 2

Hybrid Panels Versions  First version of hybrids had dot hatch at locations where jigs contacts surface  Results in up to ~40  m tilts that are different for the 8 hybrid locations in panel  As such, we used these panels to learn how thin a glue layer could be made and if it would be possible in large scale productions  Provided modules to allow for development/studies of BCCs, PPB, HSIO developments, SP and DC/DC Upgrade Project Office September 30, 2010  New version of hybrid have landing pads which are flat and planar w.r.t. ASIC sites to ~10 µm RMS  Already shown to make ASIC attachment much easier w/o glue wicking  Ordered 15 panels (120 hybrids) and have obtained glass sensor dummies so we can do a proper glue study to set pattern and “final” thicknesses  First gluing using new hybrids, hybrid flat at ~10  m RMS Tabs Landing Pads Laser cut 3

Stave Module – Noise Signature ATLAS Upgrade Week November 10, 2010  In testing, we see systematic column-to-column variation in the noise caused by increased load capacitance to the ABCN-25 front-end due to the close proximity of hybrid ground/shield (65  m nom.) and within a column due to the tilts induced by dot hatch.  Noise is fairly consistent with simple model treating the additional capacitance in the same manner as the sensor backplane capacitance  Underestimates at large separations Nominal Thickness  I believe (I might be incorrect) the minimal increase to the load capacitance would be equal to that coming just from glue.  Changes the interstrip capacitance in the ratio of sum of dielectric constants of (glue+silicon) and (air+silicon)  Increases interstrip capacitance by 0.2 pF/cm coverage  With current hybrids which overlap by 1.5 cm and 0.9 cm for outer and inner columns, this results in a noise increase of 25 and 15 e- respectively with ABCNext noise slope (80 e-/pF) For 40µm glue layer, expect ~610e on inner strips and ~630e for outer strips 4

Hybrid-to-Sensor Glue Thicknesses ATLAS Upgrade Week November 10, 2010  Due to new knowledge gained from first hybrid panels on the uniformity of hybrid thickness/flatness, noise performance and thin glue layers, I suggest that new nominal hybrid-to-sensor glue thickness to be set to 100  m  Makes module assembly and noise much less sensitive to variations in glue and hybrid thicknesses  Would results noise of ~ e- with current shielded hybrids  Potential issues  Increased ASIC temperature - thermal models prediction increase of ASIC temperature of 1 C° changing thicknesses from 40  m and 100  m (100  m is already default in all previous thermal models shown)  Increased mass - With current module build would increase module mass by 0.3 g (2%) and radiation length module relatively by 1%.  I strongly believe advantages to producability and component yield far outweigh these potential issues and unless there is strong disagreement with this I will set jigging for 100  m. 5

Production Status ATLAS Upgrade Week November 10, With old hybrid panels without landing pads 12 modules made so far, all tested with BCC frames 7 at RAL (4 mounted on stavelet) 2 at CERN cooling down after irradiation 3 at Liverpool, 1 for DC/DC load, 2 used “failed” sensors for new wire bonder (BJ820) commissioning (1 with epoxy under ASICS) With new hybrid panels with landing pads 8 new hybrids bonded and fully functional New landing pads work with very good uniformity of silver epoxy 3 modules assembled Shieldless/shielded module tested with BCC Other two await wire bonding

ATLAS Tracker Upgrade Week, 23rd-27th Feb 09 Module Production Tooling Status  2 sets of hybrid/module production tooling will be completed by end of the week  Cambridge is visiting Monday-Tuesday next week to training on how to use them which will generate use documentation  Second set will be sent to West Coast (LBL/UCSC) with this instruction set  Jig Status  The hybrid jigs for ASIC attachment, bonding and testing are “final” and shouldn’t have to change near term  The module assembly jig will need updates, for example after gluing studies to set “final” glue thicknesses. For now, shims have to be used to set heights  Relatively easy to send out to users  The module bonding and testing jigs are also “final”  We may be able to make additional sets of hybrid jigs in the near term to get other sites started in a few months ATLAS Upgrade Week November 10,

Further Material Reduction ATLAS Upgrade Week November 10, With current stave module and ABCN25, discretionary material dominated by copper and ASIC Both already will be reduced with new ASIC set, i.e. half the ASICs and roughly half the hybrid area To learn as much as we can with current ASIC set, we will first focus on removing copper and then discretes More an advantage for hybrid stuffing in production than mass Biggest copper removal would be current thick shield (~20  m or ~30% of copper weight) See next slide on shieldless module Next reduction would be reducing copper content in power layer

ATLAS Tracker Upgrade Week, 23rd-27th Feb 09 Shieldless Module  Assembled module with one shielded and one shieldless hybrid  Used 40  m glue thickness.  Shieldless hybrid ground plane 75  m from back of hybrid (50  m pre-preg+25  m solder resist)  Roughly equivalent to 100  m glue with shielded hybrid for load capacitance  Tested in SP chain using SCTDAQ and BCC with shieldless module AC-coupled  No high noise channels seen in 3pt gain measurement  Will follow up with 2 trigger test once made available (HSIO) ATLAS Upgrade Week November 10, Outer Column- 615 e- Inner Column- 601 e- 1fC 3 point gain, untrimmed No reduction in electrical performance yet for going to shieldless hybrid. Reduce copper by ~30% and hybrid circuit production costs by ~30%.

ATLAS Tracker Upgrade Week, 23rd-27th Feb 09 Near term Plans  Distribute production tools to 2 site groupings  QA on new shipment of 120 hybrids ~Nov. 15 th  Take time to do proper glue study to optimize hybrid-to-sensor glue uniformity and coverage  Using glass sensors dummies and new shipment of hybrids  Consolidate metrology programmes (both data taking and analysis)  Make another small submission of hybrid panels to test more ideas to improve flatness of hybrid after re-flow and to further reduce mass (removing copper for power and ground planes)  Make a frame compatible with the DC/DC stave package for single module test  Start testing of the 2 irradiated modules at CERN ATLAS Upgrade Week November 10,