Frank Hartmann 10.04.03

Module Construction Meeting 1

Analysis on TEC Expressline II modules

Two different topics: • Strip defects (3 modules)• Global IV (2 modules)

Frank Hartmann 10.04.03

Module Construction Meeting

Good & Bad news: Add. PinholesNo problem due to bonding!

3 (+2 later) additional pinholes were reported by Aachen wrt QTC in

Vienna!Investigated in KA with QTC and DAQ!1. 3 pinholes were related to deep scratches!2. 1 burn!?!3. 1 misstag

Module 644 strip 358Reported add. pinhole!

Frank Hartmann 10.04.03

Module Construction Meeting

Scratches:sensor defects (mod 642)

100 200 300 400 5001E-10

1E-9

1E-8

1E-7

Module 642Leakage current

Leak

age

curr

ent [

A]

Stripnumber

200 300 400 500

0,0

2,0x10-6

4,0x10-6

6,0x10-6

8,0x10-6

1,0x10-5

1,2x10-5

module 642Pinhole measurement

Idie

l [A

]

stripnumber 320 322 324 326 328 330 332 334 336 338 340

2,0x10-6

4,0x10-6

6,0x10-6

8,0x10-6

1,0x10-5

1,2x10-5

module 642 Pinhole measurementExploded view

Idie

l [A

]

stripnumber

320 322 324 326 328 330 332 334 336 338 34010-10

10-9

10-8

10-7

module 642Leakage current Exploded view

Leak

age

curr

ent [

A]

Stripnumber

Strip 330: pinhole

Strip 328: leaky

1 Scratch from strip 327 to 331 produced 2 different defects!

Module 642 strip 329,330,331

Frank Hartmann 10.04.03

Module Construction Meeting

Module 642 -- strip scan on module

100 200 300 4001,00E-010

2,00E-010

3,00E-010

4,00E-010

5,00E-010

6,00E-010

module 642

Cou

plin

g ca

paci

tanc

e [F

]

stripnumber

Coupling capacitances: all in specsOverflow @ strip 330 pinhole

0 100 200 300 400 500 6001,5x106

2,0x106

2,5x106

module 642Rpoly

Rpo

ly [O

hm]

Stripnumber

Rpoly: all in specs

NB. Strip 1 reported as a pinhole:1. is dubious in the DAQ, but not clearly identifiable as pinhole!2. shows no damage!3. is no pinhole according to the Idiel measurement at QTC!

Frank Hartmann 10.04.03

Module Construction Meeting

Mod 643 add pinholes betweenDEC02 to JAN03

Strip 221

Strip 511More on this one later

This happened somewhereafter the first module tests!

Frank Hartmann 10.04.03

Module Construction Meeting

IV

Frank Hartmann 10.04.03

Module Construction Meeting

IV problems reported by Aachen

• For a “good” IV evaluation (with a dubious first one) one should take at least fast 2-3 IV ramps

OR ramp up – wait – IV during ramp down.• The stepping of 100V done in Aachen was not suited for full

modules (there’s a chance for higher values)

Module 642 is fine (more on this) (mod 503 fine up to ~500V, then fast increase to ~10µA to be investigated).

Module 643: early breakdown at 100-200V (more on this one)

Frank Hartmann 10.04.03

Module Construction Meeting

Module 642 High IV + early soft breakdown

-50 0 50 100 150 200 250 300 350 400

2,0x10-6

2,5x10-6

3,0x10-6

3,5x10-6

4,0x10-6

module 642I-t @ Vbias = 500V

Glo

bal l

eaka

ge c

urre

nt [A

]

Time [s]

0 100 200 300 400 500-5,0x10-7

0,05,0x10-71,0x10-61,5x10-62,0x10-62,5x10-63,0x10-63,5x10-64,0x10-6

IV on module 642 (2 sensors)

Glo

bal l

eaka

ge c

urre

nt [A

]

Voltage [V]

Slight but non-criticalincrease in IV! Compare to the 40µA limit! Initial current decrease with time!

Known IV behaviour of sensors!

4µA

2µA

Frank Hartmann 10.04.03

Module Construction Meeting

Mod 643 High IV + early soft breakdown

Frank Hartmann 10.04.03

Module Construction Meeting

IV reported by AachenMod 643

First IV is fine!

´What happened?

Frank Hartmann 10.04.03

Module Construction Meeting

Module 643 (history)

• Full module shows high global IV• Optical inspection showed possible candidates for the high IV,

– NO candidates on the edges– NO; on the visible part of the backplane.– Yes; on strip level– Yes; on bias / guard region

• Strip scan (leakage current) on W6A (on module) show nominal currents (W6B not accessible)

Removal of bonds (for further deep investigation on indiv. Sensors.)

Frank Hartmann 10.04.03

Module Construction Meeting

Module 643 history (cont.)

• IV on W6A is ok, IV on W6B shows early breakdown as full module!• Cleaning improved the current but did not solve the problem:

– A) Isoprop, B) isoprob plus tissue, (C) ultrasonic bath)• Strip scans (leakage current) on both sensors show nominal currents! IV problem is NOT located in the strip region!

Remaining defect location: Backside, Guard-, Bias, n++ -region!

Removal of W6B with a scalpel no further increase in IV!NO visible breaks on the backplane (add. inspection on the edges)

Remaining defect location: Guard-, Bias, n++ -region!

Frank Hartmann 10.04.03

Module Construction Meeting

IV on module 643

Closer investigationon W6B SENSOR

Starting assumption:1. indiv. strip failure

as seen on sensors2. backplane cracks/chips3. guard scratches4. bias scratches5. contact of guard and n++

0 100 200 300 400 500 60010-8

10-7

10-6

10-5

10-4

10-3Module 643 (bonds removed)

leakage current of W6B leakage current of W6A

Glo

bal l

eaka

ge c

urre

nt [A

]

Voltage [V]

Frank Hartmann 10.04.03

Module Construction Meeting

Module 643 Strip leakage current

Individual strip currents are as expected for HPK (very low)! Other strip parameters checked for are in specs!

100 200 300 400 5000,0

2,0x10-9

4,0x10-9

6,0x10-9

8,0x10-9

module 643 strip leakage currentSUM = 300nA

Str

ip le

akag

e cu

rren

t [A

]

stripnumber

Sum of individual currents is way below the total current!(Nominal values)

Frank Hartmann 10.04.03

Module Construction Meeting

Backside – not criticalNon critical scratches on the backside compare with

scratch tests on the backside and scalpel scratches

(during removal), which did not increase the current.Exististing scratch

Non-destructive teston mini sensor

Scalpel wounds during removal Non-destructive!

Scratches on the backare probably notcritical.

Frank Hartmann 10.04.03

Module Construction Meeting

Scratch on n++,guard and bias

Scratch exists before end of bonding!

Possible defect candidate:Metal overhang defect!

Frank Hartmann 10.04.03

Module Construction Meeting

0 200 400 600 800 10000,0

2,0x10-94,0x10-96,0x10-98,0x10-91,0x10-81,2x10-8

No scratch on minisensor

Tot

al le

akag

e cu

rren

t [A

]

Voltage [V]

0 200 400 600 800

2.0x10-6

4.0x10-6

6.0x10-6

8.0x10-6

1.0x10-5

Scracht on bias and guard Exploded view

Tot

al le

akag

e cu

rren

t [A

]

Voltage [V]

Scratch test on bias & guard (minisensor)

Artifical:

Metaloverhang defect

Frank Hartmann 10.04.03

Module Construction Meeting

Preliminary field simulations (with ISE TCAD)

Frank Hartmann 10.04.03

Module Construction Meeting

Module 643 (strange)

On strip

On n++

Possible defect candidate:Short: n++ and guard

Most probable candidate!

Frank Hartmann 10.04.03

Module Construction Meeting

IV with “shorts” in the outer sensor areas

0 200 400 600 800 10001E-12

1E-11

1E-10

1E-9

1E-8

1E-7

1E-6

1E-5

1E-4

1E-3

IV standard (guard floating) IV Guard on GND IV Guard only IV Bias + Guard IV Bias (Guard shorted to n++) IV Bias (Guard 1MOhm to n++) IV Bias (Guard shorted to n++) IV Bias (Guard 10MOhm to n++)

Glo

bal l

eaka

ge c

urre

nt [

A]

Voltage [V]

-10 0 10 20 30 40 50 601E-10

1E-9

1E-8

1E-7

1E-6

1E-5

1E-4

1E-3

Glo

bal l

eaka

ge c

urre

nt [

A]

Voltage [V]

Frank Hartmann 10.04.03

Module Construction Meeting

Repair of module 643

Repair is feasible but not applicable as standard procedure! Not fully bonded yet.

Frank Hartmann 10.04.03

Module Construction Meeting

0 100 200 300 400 500 6000,00E+000

2,00E-008

4,00E-008

6,00E-008

8,00E-008

1,00E-007

1,20E-007

1,40E-007

1,60E-007

1,80E-007

undamaged small scratch with needle deep scratch with needle scratched with pencil 2B scratched with screwdriver

curr

en

t [A

]

bias voltage [V]

x3

0 100 200 300 400 500 600

1E-10

1E-9

1E-8

strip 5 (not damaged) strip 8 strip 9 strip 10 strip 11 strip 13

stri

p c

urr

en

t [A

]bias voltage [V]

x70

Total current Single strip current

GENERAL: Global IV and Individual strip IV (sensors) Scratches on QTC level! (e.g. from company or artificial)

Frank Hartmann 10.04.03

Module Construction Meeting

General comment on scratches!During Assymbly, Bonding, Testing

• DO NOT SCRATCH SENSORS / DO NOT POLLUTE THEM!!

– especially not the guardring !

– especially not the strips !

– do not break the edges !

– do not break any border line !

• SMALL SUPERFICIAL scratches are enough to change sensor/module characteristics!

1. Local & global HIGH increase of current

2. Add shorts, breaks, pinholes!

Contrary to older experiments: The high voltage sensor design is good but vulnerable to scratches!

Pollution: Use Facemasks everywhere working with open sensors/modules!

Frank Hartmann 10.04.03

Module Construction Meeting

W5 prototype production (manual)

Frank Hartmann 10.04.03

Module Construction Meeting

IV on W5

0 100 200 300 400 500 600

0,0

5,0x10-7

1,0x10-6

1,5x10-6

2,0x10-6

2,5x10-6

W5 modules (STR & KA)

S: IV on sensor before assemblyM: IV on sensor after assembly on module

m21054618 m21054615 m21054619 m21054621 m23296312 m23296324 m23296511 m23296515 S23296324 S23296511 S23296515 S23296312 S21054615 S21054618 S21054619 S21054621G

loba

l lea

kage

cur

rent

[A]

Voltage [V]