1 us testing status-anthony affoldermodule testing meeting, dec. 11, 2003 update of us testing...

1US Testing Status-Anthony AffolderModule Testing Meeting, Dec. 11, 2003

Update of US Testing StatusUpdate of US Testing Status

Anthony Affolder

On behalf of the US testing group


Fine Tuning of Fault Finding CutsFine Tuning of Fault Finding Cuts

•Combined measurements of all modules produced with old hybrids (100 resistor to inverter)

•Fit Gaussian to central core of each distribution

Found 5 region All cuts now used (but 1) outside

of this region Low noise requirement too tight

• 2.8 Deconvolution Mode

• 3.2 Peak Mode

•Led to 33 false one sensor open flags

•Re-applied fault finding with 5 requirements

• Ni > 1.55 (Deconvolution)

• Ni > 1.2 (Peak)

Old Hybrids

•Removes false flagging while not missing any new real faults

•This tuning should be done for each module type

• Root combination software available from UCSB

Channels AffectedBy Change in Cut


Comparison of Modules With Old Vs. Final Hybrids

Comparison of Modules With Old Vs. Final Hybrids

•Resistor to inverter stage changed from 100 to 50 •Good News

A small number of each type of TOB modules made

All types have similar distributions of cut variables

• Gives hope to idea that only two sets of cuts needed (1 sensor modules and 2 sensor modules)

•Bad News The noise (or gain maybe)

appears to be 5-10% lower May have to re-tune again Hopefully, gain changed due to

resistor switch

Final Hybrids

Old Hybrids


Newest CMN Problem Module (1051)Newest CMN Problem Module (1051)

• Last SS6 module built using one sensor with 1.2 A extra current (450 nA vs 1700 nA) in UCSB re-probing at 450 V.

Well within old selection criteria No large addition increase in

current during module assembly Old sensors

• 30210320274206• 30210320274214

• CMN seen in chip 46 with extremely high noise in channels 423-424

Sensor flaw seen between two channels

• Not clear if flaw cause of problem

Begins at 400 V where database and measured bias current diverge

• ~0.5 A difference

30200020001051

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500

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0 100 200 300 400 500Voltage

Bia

s C

urr

en

t (n

A)

Current(DB)

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Current(Bias Only)

Current (Bonded)


New CMN Problem Module (1051)New CMN Problem Module (1051)

• Module tested at slightly elevated voltage to measure effect as function of current

Bias current 3.7 A, < 2 A more than expected from database

• For first half of chip, CM subtracted noise a factor of ~1.75 higher than typical noise.

A very little amount of micro-discharge can cause the CM subtraction algorithm not to work properly

• CM subtraction algorithm used is same as LT, and test beam software


IV Test Results (UCSB)IV Test Results (UCSB)

• Environmental conditions tightly controlled Temperature 23.1-23.8 C RH < 30% at all times

• An increase greater than 5 A can cause CMN• Much better results with newer OB2 sensors (2002)• None of the 20 newest (2003) OB2 sensor show any increase in bias

current!!!

Sensors > 2 A

> 5 A

>10 A

>20 A

>100 A

< -2 A

<-5 A

<-10 A

OB2 (’00-01) 15% 9% 8% 5% 1% 8% 3% 1%

OB1 (’00-01) 6% 3% 3% 3% 3% 3% 0% 0%

OB2 (’02) 3% 3% 0% 0% 0% 2% 2% 0%

OB2 (’03) 0% 0% 0% 0% 0% 0% 0% 0%

Probed Current @ UCSB (400 V) – QTC Measurement (400 V)


IV re-probing (FNAL)IV re-probing (FNAL)

•FNAL has begun extensive re-probing program

See R. Demaria’s talk in sensor meeting

Plan on re-probing all sensors received so far

•328 sensors already re-probed 24% are Grade B (>1.5 A) >15% have >1.5 A increase

in bias current relative to QTC measurements

• Earlier indications are that the agreement between QTC and re-probing improved in 2003 sensors

• 81 sensors from 2003 re-probed so far

Idb vs Ifermi @ 400V - 2002

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I Production DB (microA)

I F

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icro

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Idb vs Ifermi @ 400V - 2003

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I Production DB (microA)

I F

erm

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icro

A)


CMN vs BatchCMN vs Batch

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5

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35

Number of Sensors

138 143 147 148 150 202 203 216 218 219 220 318 323

Production Week

•Sensors which cause CMN are fairly evenly distributed throughout production years 2001-2002

•Early indications are that 2003 may be better Extremely low statistics Only low bias current sensors used


Study of Common ModeStudy of Common Mode

• The common mode point is calculated event-by-event for groupings of 32 channels

The spectra of the common mode is fit for groupings within a chip with CMN problems

• Excluding the grouping with high noise channel

• Spectra is fit with two Gaussians Central core plus tail Fit parameters are:

• Fraction of events in tail

• Width of central core

• Width of tail

• Study how parameters vary with current


Fit Result of Common Mode PointFit Result of Common Mode Point

• Fraction of events is flat with bias current (~strip current)

• Width of central core increases with bias current (~strip current)

• Width of tail increases with bias current (~strip current) and may flattens out at some current

Fraction of Events in Tail

0.00

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Bias Current (nA)

Frac

tion

1011

1010

1014

1015

Width of Central Core

0.00

0.20

0.40

0.60

0.80

1.00

1.20

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Bias Current (nA)

Wid

th (

AD

C) 1011

1010

1014

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Width of Tail

0.00

2.004.00

6.008.00

10.00

12.0014.00

16.0018.00

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Bias Current (nA)

Wid

th (

AD

C) 1011

1010

1014

1015


Studies with “Final” SensorsStudies with “Final” Sensors

• 10 modules produced with 20 “final” production sensors OB2 produced in weeks 18-23 of 2003 Extremely high quality

• Bias currents between 1-2 A

• Only 2 pinholes not indicated in sensor database• No high noise channels

• Effects of thermal cycling/strain studied Modules fixed to cold box plates at thermal contacts by screws

• Modules thermal cycled for about a week

1 mm shims added under 1 or 2 contact points in order to stress silicon

• ~3 more than offset in rod attachment points


Effects of Strain on ModulesEffects of Strain on Modules

• Modules attached to cold plate with 4 screws through thermal contacts

• To test the effects of twisting modules, 1 mm shims added under thermal contacts

Bias current measured with 1 or 2 shims for all 10 modules

• No change in current seen

1 mm shim

1

2

3020020020506 Strain Study

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Voltage

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rren

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A)

Current(clamps)

Current (screws)

Current (1-1mm shim)

Current (2-1mm shim)


Modules Thermal CyclesModules Thermal Cycles

• Modules thermal cycled on modified cold plates with/without shims 168 module-hours with a total of 36 thermal cycles without

shims ~1000 module-hours with a total of ~200 thermal cycles with 2

shims

• No change in bias currents or noise seen


Single Rod Test Stand at UCSBSingle Rod Test Stand at UCSB

•Complete set of electronic ready to test single rods

Test box provides dry, dark, and electrical isolated environment

Connects to Rod burn-in chiller for cooling

•First production rod tested in stand (J. Lamb & P. Gartung)


Rod Testing ResultsRod Testing Results•Faults clearly seen in rod using new LT

Only opens on rod so far•Laser gain differences add complication to data analysis

Fixed noise cuts will NOT work due to 50% variation in laser gain

Hopefully laser gain can be measured by header height

•Similar work on optimization of calculation of pulse height & peak time variable needed as in module LT

See P. Gartung’s talk•More statistics needed in order to know how best to test rod

ARCS

Rod LT

1 us testing status-anthony affoldermodule testing meeting, dec. 11, 2003 update of us testing...

Documents

us testing group slide

sensor meeting plan

ucsb re probing

final hybrids old hybrids

module assembly old

sensor flaw

peak old hybrids

cut slide