Executive summary from Bonding WG Meeting 15 July 2003

1
Executive summary from Bonding WG Meeting 15
July 2003

• Salvatore Costa
• INFN Catania

2
News

• New Coordinator
• Alan Honma ? Salvatore Costa
• I take up administrative tasks
• Alan stays on as Technical Advisor
• New Center
• Hamburg

3
Center activity updates/problem reports
Center Activities/Problems
Aachen Vibration test on a R6 TEC Module ? broken bonds as in US TOB Modules
Bari Bonding 1st real-final Mod, found problems at PA ends, not supported by spacer (Suggested solution ?equip jig w/ extensions to slide under PA opposite edges)
Catania 1 machine out of 2 stopped working looking into problem
Fermilab Acquired 3rd machine dedicated to CMS. Previous problems bonding on TOB Pas solved by cleaning residues from pads, with alcohol and swabs
Firenze Also difficulties bonding at PA ends (see Bari)
Pisa Pull Electrical Test results on Sensor Test Structures (see)
Santa Barbara Bonded 19 TOB mod before machine had hw problem (fixed). Pad cleaning w/ citric acid solution, a technique Alan fears is dangerous long-term
Strasbourg Observed bond lift-offs, due to jig vibrations. Done Pull Test on Test Structures
Torino Pull study of Bond Force vs. U/S Power on RMT Pas (see)
Vienna Bonded w/ no problems 1 real-final TEC module out of 4 recently received
Zurich Pull Tests on recently delivered PAs excellent results on all 3 batches, including the one declared unbondable at other Centers. Bonded first alignment module.
4
Bonding-DB Usage Statistics

• I/F (v.2.0) installed
• _at_ Catania 4/14
• Locally (out-of-the-box) 6/14
• Locally (with mods) 2/14
• _________________________
• CENTERS OK 12/14
• No info 2/14

• DB-ok Modules bonded
• Yes 7/14
• dont know 4/14
• No 3/14
• Data in DB from 5 centers (19 Modules)

Change to Bonding-DB I/F remove requirement of
Sensor data in DB
5
PA Bonding Problems

• In recent bonding tests of the RMT pitch
  adapters, Alan encountered
• batches that fail the bonding tests
• AND
• batches with significant large variations in
  bonding quality (from PA to PA and even within a
  PA) such that there were both passing and failing
  tests within the same batch.
• This means a sample test of a batch is not
  sufficient to identify problematic batches (which
  is what they have been doing so far).
• I am no longer confident that those batches that
  "passed"
• in our single sample tests are necessarily good.
  
• However, the Zurich Delvotec 6300 bonding
  machines which are at CERN Prevessin could easily
  bond every PA with no problems using their
  standard parameters.
• Then Alan was able, after a lot of searching, to
  find a set of bonding parameters which yielded
  good enough results to pass the bond pull tests.
  However, these parameters are very far from
  standard set and it is not clear if they are
  really safe ones to use in the long term.
• 5

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Attacking the problem

• Difference in bondability between CERN and Zurich
  machines might be due to the frequency of the
  ultrasonic generator.
• Zurich Delvotec 6300's
  60KHz
• CERN Delvotec 6400's (as well as all other 6400's
  in CMS) 100KHz
• Small batches of RMT PAs sent out/distributed
  yesterday to some centers, to extensively test
  them on individual machines
• pull test w/ standard parameters
• search of optimal parameters
• correlate w/ machine frequency
• Possible replacement of ultrasonic generator (and
  in some cases also transducer) in faster
  machines is being considered. (Cost 15 kCHF)

7
Changes to Bonding Procedure

• PA problems call for more extensive bond pull
  testing.
• Existing procedure already calls only for 10
  test bonds on every PA prior to regular bonding,
  but it is not really enforced in that results
  are not to be recorded into DB
• Add bond test data on PA to Bonding Tables in DB
• Include destructive bond pull test on the real
  thing, that is the PA-Sensor and Sensor-Sensor
  bonds on modules, 1 every 50th wire). Then these
  bonds have do be redone
• Add the above pull test data to Bonding Tables in
  DB
• At the moment we do not envision this as a
  permanent test procedure, but only for the
  startup (first 20 Modules per Center) and will
  be reduced to a sampling test or stopped
  altogether if found not to be needed.
• I will gather results of the above pull tests
  from DB and report them to future Module
  Production meetings as part of the QA of the
  module bonding. Centers that do not report
  (satisfactory) results will not be considered
  ready for production.

8
Breakage in TOB modules

• Drop tests carried out at UCSB.
• A short or complete glue line between PA and
  Sensor did provide protection against shock
  breakage.
• Three modules have been sent to CERN without and
  with this additional glue.
• None damaged.
• A vibration test of TOB modules with and without
  additional glue was performed in Aachen.
• Improved resistance to breakage of the modules
  with additional glue.
• Will have to investigate
• Minimum amount of glue needed to ensure
  protection
• How the addition glue will modify module thermal
  characteristics.