Pixel 2000 - notes

1
Pixel 2000 - notes

• Topics covered
• Sensor
• Front end electronics
• Integration
• Bump bonding (including roundtable featuring
  AMS,IZM, VTT)
• Multichip modules
• Hybrids
• Web page http//www.ge.infn.it/Pix2000/slides.htm
  l

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Sensor

• Interpixel insulation
• ATLAS moderated p-spray
• CMS p-stop double open ring
• 250 mm sensors
• At Elba meeting CSEM, SINTEF not too
  enthusiastic, CANBERRA ok 200 mm
• CiS produced 1st moderated p-spray in 200 mm
• IRST (Trento, Italy) has tried to produce
  p-spray and moderated p-spray

3
Sensor - continued

• Discussion with SINTEF
• HERA-B sensors moderated p-spray (3 different B
  doses for implantation )
• Before irradiation breakdown at about 200 V
  (guard ring) worsened upon irradiation. Theory
  p guard ring on the ohmic side create problem
  (punch through when depletion region reaches
  guard ring)
• P-spray versus p-stop, latter easier, very
  important for p-spray to achieve quite smooth
  implantation densities need to negotiate with
  MPI (design patented ?).

4
ROSE collaboration results

• Several talks on oxygenated wafers both at ELBA
  (2) and at PIXEL2000 (1). Oxygenated wafers very
  popular. SINTEF in the ROSE collaboration ok,
  CSEM had problems with the first iteration of
  oxygenated wafers for Horisberger, they will try
  again.

5
Bump bonding

• Industry representatives
• Annamaria Fiorello AMS, Italy (In)
• Juergen Wolf IZM, Germany (Solder)
• Ikka Suni VTT, Finland (Solder, including low
  melting eutectic used for an X ray pixel device
  with bump size 15 mm on 30 mm pitch
• Roland Horisberger reported on PSI experience
• Both In and Solder seem adequate technologies

6
Hybridization

• ATLAS specifications for flex hybrid module
• - 2 metal layers
• kapton substrate, metal traces on both faces
  (25 micron thick)
• Copper traces 7 mm thick, 75 mm minimal
  distance,
• critical issues
• - wire bonds
• - stress induced on the bumps (different CTE) and
  wirebonds

7
Hybridization (II)

• First results presented on thin flex-hybrid
  electronics thinned down to 150mm
• 3 modules tested at Genova (2 bonded by AMS)
• Module 2 is the best with very few dead channels
  and threshold 3900?260 e- and mean noise about
  210 e- (however with rather long tail) (see
  Paulina Netchaevas talk).

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