Preliminary Report on the LHCb Velo Module Production Mid-Term Review

1. Preliminary Report on the LHCb Velo Module Production Mid-Term Review Tim Jones

2. My Background • Clean room • Construction • Equipment • ATLAS SCT • Module Design & development • Endcap C • Module wire bond & test • Module Mounting • Cylinder Assembly • Final Testing at CERN • Integration with TRT • SCT Steering Group Tim Jones

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7. Attendees Dave Hutchcroft, Tara Shears, Ronan McNulty, Mike Wormald, Mark Whitley, John Carrol, Dave Muskett, David Jones, Phil Turner, Peter Cooke, Peter Sutcliffe, Mike Lockwood, Geoff Southern, Dave Wells, Karol Hennessey, Gian-Luigi Casse, Tony Smith, Themis Bowcock, Tony Affolder, Kurt Rinnert, Girish Patel, Mark Tobin Tim Jones

8. Agenda • 33 Talks from 12 people • Project Overview (1) • Assembly & QA Procedures (20) • Component Testing & Cleaning, • Gluing & cable Mounting, • Bonding, • Electronic Testing, • Metrology, • Storage & Shipping • Production Data Summaries (7) • Logistics & Infrastructure (5) • Summary Tim Jones

9. 27%Modules Completed 59% Assembly Steps Completed Tim Jones

10. Project Overview • Staff • Core assembly staff compliment stable • Academic/student departures (3) • Electronic Engineer due to join from ATLAS • ~ 50% engaged in testing • Project Management • Detailed time worksheets • Daily progress meetings • E-log • Production database with process control • Well defined Construction Authorisation Steps Tim Jones

11. Component Testing & Cleaning Procedures • Pitch Adaptors • Procedure improved to reduce bending of PA’s • Improved metrology • Sensors • Results of Liverpool testing agree with Micron • Testing extended to include current scan. • Cables • Protocol checks for line resistance, open & short. • NO HV TEST • Hybrid • Test of laminated flex before ASIC attach & bond • NO HV TEST Tim Jones

12. Gluing & Cable Mounting Procedures • Pitch Adaptor Gluing • Robot dispensed 2011 / partial cure / in-fill with 2022 (?) – needed for wire bonding • Some issues of glue contamination on PA surface now resolved • ASIC Gluing • OK • Module Assembly • General principles seem sound • Suggested (periodic) CMM metrology of turn-plate (sensor-hybrid) and pedestal jig (hybrid-pedestal) • Rapid feed-back from (final) module geometry measurement • Cable Attach • OK Tim Jones

13. Bonding Procedures • General • Procedures make use of facilities on hybrid for bonding set-up & wire pull test. • Need to remove test bonds already noted. • 2 wire bonding machines used. • Wire pull tests ~ same on 2 machines. • Class 100 room • ESD safe garments (coveralls & shoes) • Back-end • Front-end • Sensor • Minimum loop height (0.45mm) OK since edge potential ~ 40% of backplane. Tim Jones

14. Electronic Testing • NA60 System • Hybrid: back-end + front-end • Module: after sensor gluing • Laser spot scan • IV test to 250V – Should consider testing hybrid to ~500V before ASIC attach. • Observation of possible p-stop isolation issue (1 module) – cannot be seen otherwise – laser scan • Tel1 System • Full functional test + ‘burn-in’ • Bias voltage ~ depletion. Proposal to take to 100-120V. • IR camera useful in diagnosing some problems • Noise Analysis • Results for same module in both systems consistent Tim Jones

15. Electronic Testing (2) • Burn-in • Aim? • To promote ASIC failures due to ‘infant mortality’ • Module under test for ~ few hours • NOT a ‘burn-in’ test – ATLAS 90 hours. • Wrong Time? • Module (i.e. with silicon) is complex object • Re-work is much harder • Burn-in should be at Hybrid level before sensor gluing / pedestal attach and transport to CERN • What to Do? • Schedule implications • Manpower & facilities • Investigate collaboration-wide knowledge on infant mortality of Beetle ASIC • Investigate limiting throughput to 2/week in return for increasing Tel1 testing duration Tim Jones

16. Metrology Procedures • SmartScope (optical) • Bare (pre-lamination) hybrid substrate • Hybrid (post lamination) • Sensor-sensor • CMM (optical + touch) • Touch probe + video probe • Concern over safety of module – working distance ~ 3mm – suggested use of a custom jig – dangerous part only done once. Tim Jones

17. Production Data Summaries • Data presented on • Substrate & Hybrids • Pitch Adaptors • Sensors • Chip & PA failures • Bonding Statistics • Metrology • Burn-in • Data summaries beginning to be based on results extracted from production database. • Need to develop analysis tools acknowledged. • Several summary plots show significant improvements in transition from pre-production to production • Several procedures already implemented to improve quality • Silicon rotation deviation from nominal to be investigated. Tim Jones

18. Logistics & Infrastructure • Particulates on Modules • Contaminants don’t seem to affect final module yield but undesirable – attempt to understand (I volunteered somehow!) • Clean Room Environment • Temperature, Humidity & particle count stable Tim Jones

19. Logistics & Infrastructure (2) • Component Supply Summary 42 installed Tim Jones

20. Logistics & Infrastructure • Database + Process control • Consistent approach to input of data • Process control an implicit feature • Tools for data retrieval & analysis being developed. • Incidents, Issues & Risks • Failure of assembly station slide • Re-work of crushed bonds • Review of checklists, authorisation, handling Tim Jones

21. Summary • The Velo module construction team should be congratulated for the excellent documentation & presentations. • The team have a clear understanding of the assembly processes and testing protocols to meet schedule for module construction. • The team are committed to the continued development of procedures to maximise the yield of good modules. Tim Jones

22. The management of the project makes effective use of daily meetings, a production database including process control and the concept of key Authorisation Steps. Tim Jones

23. Recommendations (1) • Before re-start (~ week) • Environment • Clean-up construction area. • Segregate activities likely to create debris. • Improve visual inspection after cleaning. • Review ESD procedures – insist on use of shoe tester. • Module Assembly • Check metrology of critical jigs (turn-plate, pedestal gluing jig). • Correct sensor rotation problem. • Testing Strategy • Review HV test protocols for cables / hybrids. • Product handling • Review use of handling frames and investigate possibility of extending their use. Tim Jones

24. Recommendations (2) • Short term (~ 1 month) • Testing • Review purpose of ‘Burn-in’ with respect to earlier promotion of ASIC infant mortality. • Review LHCb-wide experience of Beetle infant mortality. • Investigate limiting production rate to 2/week in return for extended Tel1 test duration. • Review need for CMM metrology of silicon sensor surface (risk) – consider designing jig. • Supply cable testing equipment to CERN. • Investigate earlier identification of p-stop shorting problem. • Fast-track further development of database analysis tools. • Review of CERN operations (if not already done) • Large number of production modules at CERN – high value - insurance? • Ensure proper procedures in place for reception testing, integration & multi-module operation (environment, ESD, safety interlocks etc…) • Resist use of final modules as test-bed for development activity (eg. DAQ, slow control, cooling …) Tim Jones

25. Recommendations (3) • Medium Term (~2-3 months) • Group should begin to take greater interest in subsequent assembly and testing at CERN. • Unrivalled expertise in the safe handling and storage of modules. • Unrivalled expertise in the properties and operation of modules – will be crucial in integration phase. • Ensure efficient transfer of knowledge base and ‘good practice’ to final assembly. • Continue to review all assembly procedures & document accordingly. • Develop plan to document the ‘As-Built’ detector Tim Jones