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Tests on Sintef/Standford IZM (Nov09) and AMS (May10) 17 Dec 2009. Alessandro Rovani , Claudia Gemme , Gianluca Alimonti , Nanni Darbo INFN Genova /Milano. 17 devices IZM bumped received on Nov 16. FE electronic wafer AGD525X
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Tests on Sintef/StandfordIZM (Nov09) and AMS (May10)17 Dec 2009 Alessandro Rovani , Claudia Gemme, GianlucaAlimonti, Nanni Darbo INFN Genova/Milano 17 devices IZM bumped received on Nov 16. FE electronic wafer AGD525X 8 devices AMS bumped received in May 2010. FE electronic wafer S789IUX
Sintef @ Selex • Two Sintef wafers of the same batch bump-bonded last year at IZM have been bump-bonded at Selex • ATLAS FE-I3 and CMS assemblies flip-chipped • Dicing sensors was troublesome: dies detached from sticky tape used in the process. Diamond saw uses a “water” process during dicing. Selex claims they never had such problem in the past (~thousands of sensors handled for ATLAS Pixel) • Cut edge is very irregular from support wafer side, clean (~150µm from active edge) on bump side (see photos) • 4+4 assemblies flipped sent to Genova this week: 5 put on single chip board and tested.
Wafer 1: B2-6 Received assemblies from Selex
Wafer 2: B4 Received assemblies from Selex
Diced assembly 150 µm
Compare bump/back side Front side does not show dicing damage. Is only support wafer damaged? Or impacts the sensor? Bump-side – Magnification = x200 Back-side – Magnification = x200 Left side Right side
General comments on IZM • Almost all devices have high current on HV. As a 1MOhm resistance is between the PS and the DUT, a significant voltage reduction is expected in case of high current on the device. • Some devices have unusually high LV currents (main on Analog supply): they work digitally but analog injection is bad. • We have observed IV worsening in time after some handling or testing (difficult to track). • We have also observed devices initially becoming bad in LV current consumption.. • Never observed an improvement in time (also drying has no effect). • Some devices work fine, even with high leakage current. However noise is relatively high and we just could tune one device at relatively high threshold.
SINTEF/AMS • All devices have high current on HV. As a 1MOhm resistance is between the PS and the DUT, a significant voltage reduction is expected in case of high current on the device. • Some devices have unusually high LV currents (main on Analog supply): they work digitally but analog injection is bad.