Transcript CMS Sensor-TUPO

Testing of Test Structures in Vienna
Thomas Bergauer (HEPHY Vienna)
CMS Sensor-TUPO
4 May 2010
CMS Sensor-TUPO
CMS Process Qualification Center 2001-2007
HISTORY
4 May 2010
Thomas Bergauer (HEPHY Vienna)
2
CMS Sensor-TUPO
Process Monitoring on Test Structures
•
What is Process monitoring?
– Each wafer hosts additional test
structures around main detector
– “standard” set of test structures is called
“half moon” (because of its shape)
– Test structures used to determine one
parameter per structure
– Assuming that sensor and test structures
behave identically
– Some parameters are not accessible on
main detector (e.g. flatband voltage of
MOS), but important for proper operation
•
Worked extremely well during CMS
sensor production
– Several problems have been identified
during CMS quality assurance tests
TS-CAP
sheet
4 May 2010
baby
GCD
Thomas Bergauer (HEPHY Vienna)
CAP-TS-AC
CAP-TS-AC
diode
MOS 2
MOS 1
3
CMS Sensor-TUPO
Measurement Setup
•
•
–
–
–
Probe-card with 40 needles
contacts all pads of test structures
in parallel
–
–
–
Half moon fixed by vacuum
Micropositioner used for Alignment
In light-tight box with humidity and
temperature control
4 May 2010
Instruments
•
Source Measurement Unit (SMU)
Voltage Source
LCR-Meter (Capacitance)
Heart of the system: Cross-point switching
box, used to switch instruments to
different needles
Thomas Bergauer (HEPHY Vienna)
4
CMS Sensor-TUPO
Three Setups have been installed
4 May 2010
Thomas Bergauer (HEPHY Vienna)
5
CMS Sensor-TUPO
Mechanical support (Vienna)
Microscope
Probecard (green) in
support
TS fixed with vacuum
onto support
XY-Table for alignment
4 May 2010
Thomas Bergauer (HEPHY Vienna)
6
CMS Sensor-TUPO
Probe-Card to switching matrix
2nd Version
Probe-card
4 May 2010
4 pcs. Keithley 1x10 multiplexer cards
(part of switching system)
Individual shielded cables
Thomas Bergauer (HEPHY Vienna)
7
CMS Sensor-TUPO
Instruments available in Vienna
• Source Measure Unit:
– Keithley 237 and 2410
• LCR Meter
– Keithley 595 (quasistatic)
– Agilent 4274A (10Hz-100kHz)
– Agilent 4285A (75kHz to
30MHz)
• Switching System
– Keithley 7002
– 4x5 pt. matrix cards 7153
– 1x10 pt multiplexer cards 7154
4 May 2010
Thomas Bergauer (HEPHY Vienna)
8
CMS Sensor-TUPO
Software: Labview
Blue Fields:
Obtained results
extracted from graph
by linear fits
(red/green lines)
Yellow Fields:
Limits and cuts for
qualification
Fully automatic
measurement
procedure takes
approx. 30min per half
moon to produce this:
4 May 2010
Thomas Bergauer (HEPHY Vienna)
9
CMS Sensor-TUPO
Passed/Not Passed Lights
•
•
•
After all measurements
finished
Window pops up
One light for each test
–
–
Green: within limits
Red: out of limits
•
Allows immediate
judgment about quality
•
Pressing “OK” button
writes data directly into
Tracker Construction
database (Oracle)
4 May 2010
Thomas Bergauer (HEPHY Vienna)
10
CMS Sensor-TUPO
Example of identified problems
Inter strip resistance issue during CMS sensor
production
•
•
•
•
•
4 May 2010
Limit: Rint > 1GΩ to have a good
separation of neighbouring strips
Each dot in the left plot shows
one measurement
Value started to getting below
limit
We reported this to the company
Due to the long production
pipeline, a significant amount of
~1000 sensors were affected
Thomas Bergauer (HEPHY Vienna)
11
CMS Sensor-TUPO
Solved Problems
•
In total, more than 4500 Half
moons have been tested in the
three labs
•
Different problems of several
sensor batches have been
discovered, e.g.:
–
–
–
–
–
•
Too high flatband voltage
Too high poly-Si resistor
Too high Al sheet resistivity
Too low inter-strip resistance
Too high bulk resistivity
3.5 kOhm
Most of the issues have been
solved by the vendors after an
intervention from us
4 May 2010
Thomas Bergauer (HEPHY Vienna)
12
CMS Sensor-TUPO
Instruments and Cold Chuck
ACTUAL SETUP FOR SLHC UPGRADE
4 May 2010
Thomas Bergauer (HEPHY Vienna)
14
CMS Sensor-TUPO
Setup today
Picture above shows the current status of the setup
• Unchanged (wrt. CMS sensor production): SMU, LCR-Meter and
other instruments
• New: cold chuck for testing irradiated structures
• Different: currently no probe-card, but individual needles
4 May 2010
Thomas Bergauer (HEPHY Vienna)
15
CMS Sensor-TUPO
Cold Chuck
• 2x 240W water cooled Peltier modules
• Chiller filled with alcohol/water mixture
to remove heat from back of Peltier
modules
• 2-channel power supply from Vienna
Cold box connected to peltier elements
• HEPHY-made TRHX System for
monitoring of temperatures and relative
humidity
4 May 2010
Thomas Bergauer (HEPHY Vienna)
16
CMS Sensor-TUPO
Cold Chuck in Measurement Box
Acrylic glas box
for minimizing of
dry volume;
Flooded with dry
air (DP -60 deg.C)
“glovebox” with
gloves
Opening with
cover to change
sensor/halfmoon
4 May 2010
Thomas Bergauer (HEPHY Vienna)
17
CMS Sensor-TUPO
Individual needles instead of probe-card
• Although a probe-card is
very handy for doing
repeated measurements
on thousands of test
structures, the layout of
halfmoon is fixed and
other measurements
cannot be performed
• Thus, we will keep
individual needles for the
moment
4 May 2010
Thomas Bergauer (HEPHY Vienna)
18
CMS Sensor-TUPO
Measurements performed for CMS
•
•
TS-CAP:
–
–
•
Coupling capacitance CAC to
determine oxide thickness
IV-Curve: breakthrough voltage of
oxide
–
•
•
Aluminium resistivity
p+-impant resistivity
Polysilicon resistivity
–
Gate Controlled Diode
IV-Curve to determine surface
current Isurface
Characterize Si-SiO2 interface
–
–
–
sheet
4 May 2010
CV-Curve to determine depletion
voltage Vdepletion
Calculate resistivity of silicon bulk
MOS:
–
TSCAP
Inter-strip Resistance Rint
Diode:
–
•
IV-Curve for dark current
Bulk breakthrough voltage
CAP-TS-DC:
–
•
GCD:
–
–
•
Inter-strip capacitance Cint
Baby-Sensor:
–
–
Sheet:
–
–
–
CAP-TS-AC:
CV-Curve to extract flatband voltage
Vflatband to characterize fixed oxide
charges
For thick interstrip oxide (MOS1)
For thin readout oxide (MOS2)
MOS 2
baby
diode
GCD
CAP-TS-AC CAP-TS-AC
MOS 1
Thomas Bergauer (HEPHY Vienna)
19
CMS Sensor-TUPO
Measurements performed so far
• In November 2009 we have received one
proton-irradiated CMS halfmoon from Karlsruhe
• The structures were irradiated with protons
to 5.24E14 n(equiv) and are annealed (80min at
60°C).
• Measurements performed so far:
–
–
–
–
4 May 2010
IV on baby, diode
CV Diode and Baby with comparison
CV MOS
C_int, R_int
Thomas Bergauer (HEPHY Vienna)
20
CMS Sensor-TUPO
Measurements: IV
Non-irradiated
4 May 2010
Thomas Bergauer (HEPHY Vienna)
irradiated
21
CMS Sensor-TUPO
Measurements CV
Comparison
Unirradiated vs.
Irradiated sample
4 May 2010
Thomas Bergauer (HEPHY Vienna)
22
CMS Sensor-TUPO
Measurements MOS
Non-irradiated
4 May 2010
Thomas Bergauer (HEPHY Vienna)
irradiated
23
CMS Sensor-TUPO
Strip scans at room temperature
• We can also perform
strip-by strip
measurements of
unirradiated
sensors only (other
setup without cold
chuck)
–
–
–
–
4 May 2010
Single strip current
Poly-silicon resistors
Coupling capacitance
Dielectric current
Thomas Bergauer (HEPHY Vienna)
24
CMS Sensor-TUPO
Test Structures of new Layout
Diode
Via-TS
GCD
TS_cap
Sheet
Cap-TS-DC
Layout of new HPK wafer:
MOS
Cap-TS-AC f. C_int measurement
4 May 2010
Thomas Bergauer (HEPHY Vienna)
25
CMS Sensor-TUPO
Manpower / Timing
• Time Estimate for full half
moon: 4h
– Manual measurements, no
probe-card
• Time estimate with probecard: 30 minutes
– But: effort necessary to
design und buy probe-card
Available manpower
• Technicians
– 0-2 FTE as necessary
• Physicist
– 0-2 FTE as necessary
• Students
– 0.2 - 1 FTE
– Large effort to modify setup
– Setup not flexible for other
measurements anymore
4 May 2010
Thomas Bergauer (HEPHY Vienna)
26
CMS Sensor-TUPO
Planning/Summary
• Currently: We are re-measuring all parameters
of irradiated/not irradiated structures that our
student gets familiar with it
• Necessary modification of software
– improve fits
– DB interaction (once TrackerDB stuff gets settled)
• We will perform n-irradiation in our own reactor
for testing purposes in near future
• We are ready for the delivery from HPK
4 May 2010
Thomas Bergauer (HEPHY Vienna)
27
CMS Sensor-TUPO
Backup slides follow
THE END
20 October 2009
Markus Friedl (HEPHY Vienna)
28
CMS Sensor-TUPO
Test Structures of new Layout
Layout of new HPK wafer and
position of possible probe-card
Cap-TS-AC f. C_int measurement
4 May 2010
Thomas Bergauer (HEPHY Vienna)
29