SiW-ECAL technical meeting

→ Europe/Paris
Salle 101 (IJCLab)

Salle 101

IJCLab
ZOOM Link (ID de réunion : 614 5669 8406 Code secret : 91400)
Cacher

Participants

  • Salle 101: Taikan, Alice, Stéphane, Alexandre, Roman, Jérôme, Dominique
  • Distance: Rémi, Vincent, Adrián, Jimmy, Jihane

Note: Main points have been noted, not necessarily in the order they were discussed.

 

Gluing

  • Diagnotics
    • Seen in 2018
    • 2017
      • PCB bending ➞ Picture on the assembly bench in Orsay showing a bend and delamination in a corner.
    • The exact diagnosis has not been discussed by briefly been listed by Vincent:
      • Delamination occurred on some ASUs since 2016, in a wide diversity of situations:
        • After a plane transit (complete desoliderizing a single wafer)
        • Full or Partial loss of connectivity PCB-Wafer, 
        • mostly on the borders (see right)
        • Verified by measurement of the noise level
        • Some connection were recovered by pressure (adding the tunsgten)
        • Things are getting worse as time goes by
        • Old (FEV10) or New (FEV13) boards affected
          • Glued in LPNHE or Kyushu
    • Regluing of 2 single wafer was done in Kyushu (Picture attached)
      • Removal of glue on the PCB quite clean.
      • regluing satisfactory
        • Alignement as good ?
  • Possible causes:
    • Materiel
      • PCB's
        • Bending ?
          • measurement of old PCB could bring ideas.
        • Heat FEV12
          • Cabling: Process slow heat + peak + slow cool down
          • idea: make PCB, equip with bad ASICs
            • check mechanics
            • measure the laser profile and /or tracer arm (Palpeur) profiles.
        • Cabling
          • Require
      • Glue
        • Contact with producers
          • EPOTEK
            • Not yet
        • New producers ?
          • Henkel
          • Loctite ?  < misinterpretation ?
        • Change in composition culprit ?
          • Old glue used in Kyushu : no diffreence
      • Wafers
        • Surface
          • Aluminium
        • Dirt, Grease, etc
          • Clean it ?
            • Alcool
    • Process
      • Mixing of glue
        • Done Manually
        • Small quantities
          • ➞ errors on composition
          • Quantities: 4g / 2 ASUs
            • should go for min 25g
          • Time: 1h
            • viscosity change in 20 mins
            • 2 ASUs max.
      • Quantities
        • Pas suffisante
          • diameter points de colle ~ 2 mm
        • Par pression ≥ Volume
        • Sensor for visual inspection
          • ~20k€
            • 10k€ from AIDAinnova ?
          • Now: manual adjustment
      • Surface quality
        • Different histories
          • Glue
            • too long ?
              • Viscosity ➚
              • Garanteed for 6 months
          • PCB
          • Wafers
      • Polymérisation
        • Température suffisante ? temps suffisant ?
          • Oui ! 
        • Relâchement des contraintes AVANT polym. ?
          • Will challenge the stability ➞ No fixed results
      • Distance PCB vs Wafer
        • 200 μm from ILD
        • Release it ? To be seen...
    • Environment
      • Vibrations during transports
        • banc test du CERN ?
      • Aging de la colle
        • Temperature in stack ~ 40°C
          • Excursion ?
        • Banc climatique LLR, IJCLab
    • Manipulation
      • List of operation ?
      • Calage dans les pièces dans les rails
        • Calendier : début des soucis avec la nouvelle structure
        • Force sur les bord ➞ pression au bords des cartes
          • A mesurer
        • Ajout du W parfois en forçant ➞ pression externe au centre des cartes
          • Pression rails.svg
        • Fluctuation d'1 carte à l'autre
          • Supports inégaux
          • Bcp de manipulations
      • Trop de manipulations...
    • Mechanics
      • Standard = flatness 1% of the diameters = 2mm
        • Better becauce of symmetric design
  • Actions
    • Measure
      • Laser
        • IJCLab ATLAS benches
      • Existing PCBs
        • 1 FEV2
        • 5 FEV12
          • ≠ producers
      • Wafers
        • Instituts d'electronique
          • 300€/20 Wafers
          • Same surface
            • Aluminum + Passivation
        • Hamamatsu Kyushu
          • ~10 "broken wafers"
        • Baby wafer
          • For gluing mecahnica tests
        • C2N2
      • Aging/studies climatic measurement
        • IJClab
        • LLR
      • Vibration table
        • Kyushu
        • CERN
    • Solutions
      • Better gluing mixture
      • Add a frame around pads:
        • non-conductive glue (Taikan)
        • plastic frame (Jerome)
      • Measure of planeity before/after gluing ?
      • Fabrication d'echantillons
        • Vérification proprité mécanique du verre vs Si 500μm
        • Verre sur QUELL PCB
      • Fabrication de meilleurs supports
        • sans contrainte du W sur les cartes

PCBs

  • FEV2

Jerome

  • Heat
  • Footprint of connector
  • Analogue probe
    • 1 wire
      • to the SLboard ADC input
        • 1 already connected to AVDD
    • ASIC by config
      • only one by one
      • Capacitance ➚
      • use 0-Ω resistors to physically disconnect in case.
    • Which line
      • Read-register line unused (and some others ?)
        • read return
        • SL read
      • SOIC?
  • HV
    • decoupling implemented
  • Mechanical
    • Small holes would be useful (Alice)
      • for assembly / disassembly
    • But there possibility to add 1-hole dominoes soldered on the boards for pliers.
    • no more half holes (looking at the wafers)
  • SLBoard
    • Meeting on Wednesday (day after)
    • 1 wire to be added for HV reconnexion.
    •  

Next meeting ≥ calice

  • 21/10

 

Il y a un compte-rendu associé à cet événement. Les afficher.