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Stripixel Sensor Pre-production at Hamamatsu. Junji Tojo RIKEN VTX Meeting, Dec. 9 th , 2004. Pre-Production at HPK. Design 3 sensors/wafer on 6” wafer 625um and 500um thickness. Two designs : “STD” & “NEW” design. Process breakdown “STD” design w/ 625 um thickness : 6 wafers
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Stripixel Sensor Pre-productionat Hamamatsu Junji Tojo RIKEN VTX Meeting, Dec. 9th, 2004
Pre-Production at HPK • Design • 3 sensors/wafer on 6” wafer • 625um and 500um thickness. • Two designs : “STD” & “NEW” design. • Process breakdown • “STD” design w/ 625 um thickness : 6 wafers • “STD” design w/ 500 um thickness : 6 wafers • “NEW” design w/ 625 um thickness : 12 wafers • “NEW” design w/ 500 um thickness : 11 wafers • HPK process was finished. 35 wafers were processed in total. • Originally, 20 good wafers in contract. • HPK processed 35 wafers (105 sensors), since the wafer yield was unknown. • We asked HPK to deliver all 35 wafers to us (under negotiation). • Wafers are under testing at HPK.
MPD sensor MPD 6 inch wafer Photograph of Stripixel Sensor Wafer(“NEW” Type Design) MPD : Monitor Photo-Diode
Testing at HPK • Testing item • CV measurements with Monitor Photo-Diodes (MPDs) • Full depletion voltage (VFD) measurement. • There are 6 MPDs per wafer. • IV/CV measurements • Current/Capacitance characteristics as a function of Vbias. • Only a few channels were measured as a reference. • I/C measurements at V≈VFD+100 V • Measurement for all the channels • Evaluation of the strip yields (important for mass-production)
CV Measurement with MPDs • 6 MPDs per wafer : UL, UM, UR, DL, DM, DR
Wafer number CV Measurement with MPDs • Typical CV curve for “NEW” Design MPDs • Figure shows the results for “DL”-MPDs.
CV Measurement with MPDs • VFD estimated for “NEW” design wafers • ~155-175 V for 500 um wafers, ~100-120 V for 625 um
Wafer number CV Measurement with MPDs • Typical CV curve for “STD” Design MPDs • Figure shows the results for “DL”-MPDs.
CV Measurement with MPDs • VFD estimated for “STD” wafers • ~145-170 V for 500 um wafers, ~95-115 V for 625 um VFD results are close to an estimated value from wafer resistivity .
I / C GND GND IV/CV Measurement • Measured only for “NEW” design wafers. • Only one channel for all the sensors. • The 6th pad from the left in X1 pads • Guard ring and a few adjacent pads were grounded. • IV/CV in 5-500 V.
C (pF) I (nA) IV/CV Measurement • Results for wafer #1 : “NEW”, 625 um Sensor Left, Middle, Right • Preliminary result • C ~ 26, 21, 23 pF at V=VFD • I ~ 123, 49, 90 nA at V=VFD (VFD ~ 110 V ) • More results will come.
I/C Measurement Wafer #1 “NEW”, 625 um • Leakage current measurements at Vbias = 230V for all the 625um wafers. • Measurements of C for 625 um wafers and I/C for 500 um wafers are going on. • More results will come.
Expected Schedule • HPK sensor • “NEW” design sensor has the highest priority. • Delivery expected to be early next year. • Dicing & more testing at BNL in January. • StripFee prototype • Completion is expected to be ready in February (See Vince’s slides). • Detector tests • Detector integration (gluing & wire-bonding) at RIKEN in February. • Laser tests at ORNL (or RIKEN) in March.
Summary • CV measurement with MPDs • VFD =145-175 V for 500um wafers, 95-120 V for 625 um wafers • Consistent with wafer resistivity • IV/CV measurements • Measured for only for “NEW” wafers (One channel per sensor) • Preliminary result was shown. More will come. • I/C measurements • Measured for all the channels • Measurements of current for 625 um wafers were done. • C for 625 um wafers, I/C for 500 um wafers are going on. • Wafers are expected to be delivered around the early next year.