Marina Artuso 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.html

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Sensor

• Interpixel insulation: – ATLAS “moderated p-spray”

– CMS “p-stop double open ring”

• 250 m sensors – At Elba meeting CSEM, SINTEF not too enthusiastic,

CANBERRA ok 200 m

– CiS produced 1st “moderated p-spray” in 200 m

– IRST (Trento, Italy) has tried to produce “p-spray” and “moderated p-spray”

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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 ?).

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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.

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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 m on 30 m pitch

– Roland Horisberger reported on PSI experience

• Both In and Solder seem adequate technologies

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Hybridization

ATLAS specifications for flex hybrid module: - 2 metal layers– * kapton substrate, metal traces on both faces (25

micron thick)– * Copper traces: 7 m thick, 75 m minimal distance,

• critical issues:• - wire bonds• - stress induced on the bumps (different CTE)

and wirebonds

Marina Artuso 7

Hybridization (II)

• First results presented on “thin” flex-hybrid: electronics thinned down to 150m– 3 modules tested at Genova (2 bonded by

AMS)– Module 2 is the best with very few dead

channels and threshold 3900260 e- and mean noise about 210 e- (however with rather long tail) (see Paulina Netchaeva’s talk).

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Marina Artuso 9