# Presentation: 280673

## U.S. Status Update

- Lenny Spiegel
- On behalf of the U.S. Silicon Tracker group
- A summary of U.S. module production
- and testing results based on recent deliveries
- of ST Qualification Sensors.
- And some information on HPK sensor probing.

## U.S. SiTracker Group

**Brown University**
- R. Hooper, G. Landsberg, C. Nguyen, H. Nguyen
**University  of California, Riverside (UCR)**
- Gail Hanson, Gabriella Pasztor, Patrick Gartung
**University  of California, Santa Barbara (UCSB)**
- A. Affolder, S. Burke, C. Campagnari,  D. Hale, (C. Hill), J. Incandela, S. Kyre, J. Lamb,  S. Stromberg, (D. Stuart), R. Taylor,  D. White + technicians.
**University of Illinois, Chicago (UIC)**
- E. Chabalina, C. Gerber, L. Nigra, T. Ten
**Fermilab (FNAL)**
- M. Demarteau, A. Ronzhin, K. Sogut, L. Spiegel, S. Tkaczyk + technicians
**University of Kansas (KU)**
- P. Baringer, A. Bean, L. Christofek, D. Coppage
**Mexican Consortium:**** **
**Cinvestav:** H. Castilla, R. Perez, A. Sanchez
**Puebla:** E. Medel, H. Salazar
**San Luis Potosi:** A. Morelos
**University of Rochester (UR)**
- R.Demina, R. Eusebi, E. Halkiadakis, A. Hocker, S. Korjenevski,  P. Tipton

- *Working at FNAL SiDet center.

## Previous Experience

| Modules constructed* | 302 | % |
| --- | --- | --- |
| ARC test grade A | 244 | 81 |
| ARC test grade B | 26 | 9 |
| ARC test grade F(/F) | 32 | 11 |
| CMN modules | 16 | 5 |
| Other failures attributable to sensors | 8 | 3 |

- *Includes 26 TEC modules at UCSB

**Module Production with Selected (Grade A and higher) ST silicon  – Combined Results From FNAL and UCSB**

## Common Mode Noise Issue

- Affecting 5% of TOB modules (after screening based on sensor currents and grades).
- Generally leads to a failing grade in ARCS testing. A/F, B/F, etc.
- Some evidence for CMN problems developing spontaneously with time.

**Evidence of CMN in a second APV 3 months later**.

## Previous Experience

## ST Qualification Exercise

- ST qualification silicon delivered in two batches
- Set I: 266 sensors (132 OB1, 110 OB2, 24 R5)
- Set II: 176 sensors (76 OB1, 100 OB2)
- TOB hybrids restricted to two batch IDs due to via/floating pedestal problem
- 040312_TOB4PU and 040407_TOB6PU
- Production/testing sequence: IV measurements, Gantry assembly, wire bonding, ‘encapsulation’, ARC testing, LT testing, post-LT (ARC) testing.
- Minor variations between FNAL and UCSB.
- IV measurements only made on Set I.
- 3-day LT test scenario for Set 1 and 1⁄2 day scenario for Set II.
**In general, LT and post-LT tests do not reveal new problems; **_**the primary measure of module (electrical) quality is the first ARC test**_**.**

## Sensor Selection Rules

- OB1 and OB2 samples treated similarly:
- Sensors are divided into two groups: those with depletion voltages above 200 volts and those with depletion voltages below 200 volts.
- Within a given group sensors are paired so as to level the number of bad channels per module.
- Sensors are ordered so that the outer sensor has the larger number of wire bond pulls.
- A small number of sensors came to us with a FAULTY faulty status
- For example 30210434890026 and 30210340224723 at FNAL
- In the former case the sensor DB entry was ‘repaired’ and the sensor was used to construct a module which eventually received an A testing grade!

## Typical Build Plan

## Sensor Probing

- Output of sensor grading program for set I sensors at FNAL

- Some probing results for set I sensors from UCSB. Dashed curves taken immediately after solid curves (evidence of surface effects?!).

## Sensor Long-Term Probing

## Summary of FNAL Testing Results

- 44 modules tested so far
- 16 OB1, 25 OB2
- Failure rates/sources
- 0.27% Bad channels on average
- 0.23% Known bad sensor channels
- 0.03% Unmarked bad sensor channels
- 0.01% bonding
_**No CMN modules**_
**Sensor quality/fault finding much improved**
- Module Grading
- 44 Grade A

- Module LT Testing
- First production tested with 3 day cycle
- 7 thermal cycles
- 1 day sitting at 400 V, -20 C
- 44 modules tested
- Set II tested with 1⁄2 day scenario due to time constraints
- 3 thermal cycles

## Summary of UCSB Testing Results

- 133 modules tested so far
- 61 OB1, 60 OB2, 6 R5N, 6 R5S
- Failure rates/sources (excluding CMN modules)
- 0.27% Bad channels on average
- 0.23% Known bad sensor channels
- 0.03% Unmarked bad sensor channels
- 0.01% bonding
_**Sensor quality/fault finding much improved**_
- Module Grading
- 129 Grade A
- 2 Grade A/F
- 2 CMN modules
- One starts at 400 V, above 450V after 10 minutes
- One Predicted By Sensor Group (see next slide)
- 1 Grade B/F
- 2nd sensor’s backplane not connected to HV
- 6 channels damaged in determining problem
- 1 Grade C/F
- Hybrid pickup tool damaged 64 APV-PA bonded-not repairable (See next slide)

- Module LT Testing
- First production tested with 3 day cycle
- 2 day thermal cycling
- 1 day low RH%, 400 V, -20 C
- 43 modules tested
- 3 noisy channels not present at all temperatures
- 2 channels shorted in Inverter On in the cold.
- Second production testing with over-night cycle only due to time constraints
- 12 hour thermal cycle
- 8 modules tested
- No problems seen

## Predicted CMN Module

- Sensor group sent UCSB two OB1 sensor which have potential for CMN
- ISTRIP measured with AL strip held at 5 V
- Sensor 3021034736742
- Channel 228
- Sensor 3021033499570
- Channel 723
- Module has CMN in channel 723 between 60-250 V depending on time biased
- Channel 228 has slightly elevated noise (1.4 → 1.8 ADC) but no CMN
- 5V test appears to have predictive power for CMN potential

## Other Testing Considerations

- Although the vast majority of the qualification modules received an A grade, in several cases some corrective action and retesting was necessary. For example, of the FNAL set I (44 modules)
- 5 required a change in the VPSP setting from 40 to 36.
- 1 had touching bonds on the backside of one of the APV’s.
- 1 had a severed HV line on the kapton.
- 1 had a new pinhole.
- 1 repeatedly blows the fuse in the HV protection circuit.
- Some of this remediation work is clearly unrelated to issues of sensor quality; however, from a production throughput perspective we would like to see the extra work and repeat testing as limited as possible.

## Comparison of ST Sensor Samples

|  | Selected | Qualification |
| --- | --- | --- |
| IV curve profile | traditional | steep rise at turn-on |
| Average current at 450V per sensor (microamps) | 0.7 | 2.0 OB1, 2.5 OB2 |
| Average number of bad channels per sensor | 1.9 | 2.0 OB1, 1.7 OB2 |
| Module CMN rate | 16/302 | 1/220 |
| Other module failures attributable to sensors | 8/302 | 0/220
 |

## ST Qualification Conclusions

- From the perspective of module testing the ST qualification sensors represent a clear improvement over grade A(+) selections from earlier ST deliveries.
- This is seen not only in the fraction of CMN modules but also in the module test grade distributions
- Mask defects/scratches  noisy channels
- Excess module current
- Agreement between predicted and measured faults.
**It would help if the reasons for the improvements were fully understood so that one could be confident that they would be sustained in future ST batch production.**

## HPK Sensors

- 20 HPK 6WA and 20 HPK 6WB sensors have recently been probed at Rochester University.
- One sensor (6WA 0832) failed with high Rpoly > 2M 100 strips
- All capacitance values within spec
- Vdepl within spec
- Rpoly ranges from 1.6 to 1.9 M
- One sensor showed early breakdown, was retested; breakdown was not reproduced. Guard ring issue?

**Rpoly (M********)**

## HPK Sensor Probing at UR

- Individual strip leakage currents in nanoamps for HPK 6WA and 6WB sensors.
- We are eager to see the results of testing comparable samples of HPK modules (compared with the ST samples).

## First HPK Module Results From UCSB

- 6 R6 modules built using new HPK sensors
- All 6 modules are perfect
- Not a single flaw
- IV profile as expected
- Turn-on at low voltage
- Plateau bias current between 600-800 nA