1. Frank Hartmann --- Karlsruhe 2 nd bond test 2nd bond test pieces received from.... 11 institutes sent in their 2nbond sample Torino, Wien, Karlsruhe, FNAL, Bari, Padova, Strasburg, Santa Barbara, CERN, Florence, Zürich (Bonding machine 1 & 2)

2. Frank Hartmann --- Karlsruhe 2 nd bond test 2 nd bond test (pinholes due to bonding) Test procedure: 1.Measurement of ST (in KA) and HPK (in Wien) teststructures for IV and pinholes 2.Assembly PA-ST-HPK-PA @CERN 3.Bonding at all bonding centers 4.Retest of IV and pinholes (in KA) Since the DC pads are covered by bonds, we biased the sensor with –1V forward bias and measured the current on the AC (2ndbond Pad)  Significant increase of current at shorted dielectric

3. Frank Hartmann --- Karlsruhe 2 nd bond test Retest after bonding IV on HPK and ST DC current measurement @ Vbias –1V on both sensors Try to identify the sensor with the measured ST sensors by their former pinhole measurements (No single pinhole on HPK teststructures) Only in case of additional pinholes (no.definite identificaton) we removed the middle bonds, and remeasured both sides to identify the sensor, where the pinhole happened.

4. Frank Hartmann --- Karlsruhe 2 nd bond test Known occurences Karlsruhe: bondhead crashed on one PA  Bonds missing: –FNAL: 1,57-66,81,86,94 –Padova: 1,91 (HPK-PA); 128 (ST-PA) –Strasburg: 1,2,29,43,127 (HPK-PA) FNAL: scratch on sensor at strip 82 PA only 127 strips  first bond often missing FNAL bonded sen-sen TWICE (on 2 AC pads)

5. Frank Hartmann --- Karlsruhe 2 nd bond test Results Unfortunately, we got NO reasonable results from the IV characteristics! –The ST structures came from a very early batch and also the HPK had much higher currents, and even low breakdown voltages for all pieces –We assume assembly (handling-dryness) problems. –Only the Santa Barbara piece (with 2 HPK structures) showed reasonable IV characteristics More important: Pinholes happend at bonding 

6. Frank Hartmann --- Karlsruhe 2 nd bond test Example measurement

7. Frank Hartmann --- Karlsruhe 2 nd bond test Result II We had a 100% match of pinholes before and after bonding for all institutes No single pinhole was created during 2 measurements, assembly and „bonding“. Gratulation to all bonding centers

8. Frank Hartmann --- Karlsruhe 2 nd bond test FNAL bonded sen-sen twice