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Module Bonding Working Group. Salvatore Costa Universit à di Catania and INFN – Sezione di Catania. Bonding Facilities. Bonding Machines. Bonding Times per Module. Pre-bonding visual inspection: 10min ARC test: 15-30min Bond: 5-35min 5min for K&S
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Module BondingWorking Group Salvatore Costa Università di Catania and INFN – Sezione di Catania
Bonding Times per Module • Pre-bonding visual inspection: 10min • ARC test: 15-30min • Bond: 5-35min • 5min for K&S • 10min for Delvotec and Hesse&Knipps • Double for 2-Sen Modules • 35min for Hughes. • Post-bonding inspection: 10min • Pull test [if required] (pull, cleanup, rebond): 20min • DB entry: 5min • TOTAL: 45-90min excluding pull test NOTES: • ARC test times vary with Vpsp adjustment • Some op may be performed in parallel by different people
Maintenance, Failures, Downtime Center Maintenance schedule Failures Downtime TIB: Bari ~yearly, no contract No N/ACatania on demand,no contract Once 1 month (*)Firenze yearly by contract 2 times 2 months (*) Padova regularly by bond op. No N/APisa by bond op. as needed No N/ATorino ~yearly, no contract No N/A TEC:Aachen regularly by bond op. No N/AHamburg on demand,no contract Once 3 days Karslruhe on demand,no contract Once 1.5 daysStrasbourg yearly by contract No N/AVienna yearly by contract No N/AZurich on demand,no contract Once 2 weeks TOB:FNAL 4/year by contract Damage by Nonepower failures UCSB 4/year by contract 1/machine ~1-2 week/machine (*) Attempts (failed) to fix in house, to save money, made because prod was stopped
Bonding Failures/Rep Actions • Bonding failure detected during bonding or at post-bonding inspection: • Wire won’t stick • Bond pops up (lift off) • Foot is misplaced and causes a short somewhere • We repair these right away if we can and/or list as unbonded the strips that are such as a result of the failure or of the “repair” action. • (Bonding) failure detected during post-bonding ARCS or LT tests: • Pinhole (caused by bonding/handling accident or pre-existing and either undetected in Sensor test or on untested Sensor) • Short (caused by bonding/handling accident or by misplaced foot) • Open (bond popped up) • Same action. • Electric failure detected with ARCS at any stage (pre-bonding, post-bias-pre-readout-bonding, post-bonding or LT tests which dos not exhibit a clear link to bonding: • Increased LV current • Anomalous IV • We post the problem for the Debug/Repair Center • Electric failure detected during post-bonding ARCS or LT tests, which might be traced back to a bonding failure: • Example: “pseudo”-pinhole: At post-bonding ARCS test, a “PHL-” is found. We pull the readout bond as prescribed for pinholes but the test keeps saying “PHL-”, so the Hyb ch is damaged. Since it was OK at ARCS test on arrival perhaps we killed it with bonding. • We post the problem for the Debug/Repair Center.
Bonding Failure Rates • Global percentage of damaged channels (Hyb ch and/or Sen strips) because of bonding failures: <~0.01 % • Based on a compilation of unrepairable bond failures reported by individual centers on 20Apr2004. At that time 1180 Modules had been bonded (~800,000 bonds). • Since then reports at Meetings have indicated improvements, therefore although a more recent quantitative estimate is not available, it can only be less. • Global percentage is the average between 0 from a few centers (such as Pisa) were not a single bond failure leading to loss of channels has been observed and 0.08 % in Catania [see next slide for analysis of failure types] where the oldest bonding machines, also lacking modern amenities such as automatic correction of bond parameters with varying substrate quality, are. • Not a single module lost yet (i.,e. no module with > 2% affected channels) because of bonding failures out of 2,700 Modules bonded so far. • Only 1 module unbondable for dirty Pitch Adapter.
Module Pull Tests Performed # Modules pull tested after 01Dec2003 (at last Mtg)
Pull Test Results (Nov ‘04) Not angle-corrected yet! Average forces (g) 5g BA CT FI PD PI TO FL FL SB SB AA AA HA KA ST ST VI ZH .ss ss ss ss
Pull Test Results (Jul ‘04) Not angle-corrected yet! 5g BA CT FI PD PI TO FL FL SB SB HA KA ST ST VI ZH . ss ss ss
Pull Test Results (Jun ‘04) 5g BA CT FI PD PI TO FL FL SB SB HA KA ST ST VI ZH . ss ss ss
Loop Documentation Procedure:Uses a few of the identical symmetrical bonds we place on the PA Tests areas. • Document the original bond • Straighten a bond to (near) triangular shape • Measure the angle at the bond foot • Determine correction factor for pull strengths
1. Document the original bond • Gently push bond over with the pull tester hook until it rests flat on the PA surface, but taking care that its shape is not significantly altered. • Take snapshot of bond under measuring machine.
2. Make bond triangular • Gently pull bond up at mid-span with the pull tester hook until it takes a (nearly) triangular shape (figure below). • Gently push bond over with the pull tester hook until it rests flat on the PA • surface, but taking care that its now triangular shape is not significantly • altered.
3. Measure angle at bond foot • Take snapshot of triangularized bond. • Measure angle using measuring machine.
4. Determine correction factor (2) Correction factor: a = 1 / (2 sin) For symmetrical bond:
Module Grading from Bonding (1) Grading based on # unbonded strips • First flag in BONDSTATUS_VAL vector: • 0 if n_unbonded <1 • 1 if 1% - 2 • -1 if >2% • These are consistent to grades A,B,C of ModTest and the module is faulty with >2% unbonded strips.
Module Grading from Bonding (2) Grading based on mechanical quality of the bonds • Criteria to generate this second flag: • # Bias Bonds (Spec: 5, 15 for TIB back) • >2: grade A (flag 0) • 2: grade B (flag 1) • <2: grade C (flag -1) • # “critical” readout bonds [definition list of “critical” by Alan]: • ≤ 2%: grade A (flag 0) • > 2%: grade B (flag 1) • > 20%: grade C (flag -1) • Operator judgment on all other bonds [guidelines to issue this judgment by Alan]: • A, B, C. • These criteria will be or’ed together to generate flag.
Bonding Specs (1) • Document on Bonding web site: cms.ct.infn.it/bonding/bondspec.htm • Contents: • Bonding Specifications … • Specifications on Bonding Jigs • Specifications on Module Carriers • Specifications on Module Components and Assembly Relating to Bonding • Specifications on Working Environment • Specifications on Final Module Bonding Quality & Acceptance
Bonding Specs (2) • wire thickness and type • number of bias bonds • loop height and form • tail length • accuracy of placement in X and Y • pull strength • break on pull failure • failure rate • number of bonds with one tool
Bonding Procedures • Bonding Proc Document on Bonding web site: cms.ct.infn.it/bonding/bondproc.htm • “Reference” doc in 43 steps • Has many pictures (mainly for TIB at the moment) • Procedure to perform the 50th wire Pull Tests cms.ct.infn.it/bonding/pullproc.htm
Leave unbonded All strips in bad-IDIEL list (considered pinholes) All Isolated bad CAC (believed to have high chance to develop into pinholes with irradiation) All but lowest in a bad CAC chain (believed to represent shorts) CAC Example: 3 34 35 36 37 skip isolated 3, skip all but lowest in 34-37 chain, or: bond only 34 Leave unbonded all strips in bad-IDIEL list (although 16 % are good), i.e. do not bother looking at their actual IDIEL value. Bond all isolated bad-CAC For the consecutive bad-CAC, compute rC and consider them members of a short if rC>1.5. Then bond only the first strip in the short. If rc<1.5 bond them, as if they were isolated Skip rules Old rule New rule