construction and performance of a double-sided silicon detector module using the origami concept c....
TRANSCRIPT
Construction and Performance of a Double-Sided Silicon Detector Module
using the Origami Concept
C. Irmler, M. Friedl, M. Pernicka
HEPHY Vienna
2TWEPP 2009, Christian Irmler (HEPHY Vienna)23 September 2009
Contents
Motivation
“Origami” Chip-on-Sensor Concept
Prototype Assembly
Beam Test Performance
Summary & Outlook
3TWEPP 2009, Christian Irmler (HEPHY Vienna)23 September 2009
Motivation
“Origami” Chip-on-Sensor Concept
Prototype Assembly
Beam Test Performance
Summary & Outlook
4TWEPP 2009, Christian Irmler (HEPHY Vienna)23 September 2009
~1 km in diameter
Mt. Tsukuba
KEKB Belle
KEKB and Belle @ KEK (Tsukuba, Japan)Asymmetric machine:8 GeV e- on 3.5 GeV e+
• e+/e- linear accelerator + storage ring
• Center of mass energy: Y(4S) (10.58 GeV)
• High intensity beams (1.6 A & 1.3 A)
Linac
Belle
KEKB
5TWEPP 2009, Christian Irmler (HEPHY Vienna)23 September 2009
Belle-II
• KEKB factory upgrade until 2013• Target luminosity of 8 x 1035 cm-2s-1
• 40 times the present value• Accordingly increase of background
• Limitations of current silicon vertex detector (SVD2):– Occupancy need faster shaping– Trigger rate (dead time) need faster readout and pipeline
• Replacement of the SVD and its readout is necessary• APV25 readout chip would fit the needs
6TWEPP 2009, Christian Irmler (HEPHY Vienna)23 September 2009
Comparison VA1TA – APV25
VA1TA (SVD2)• Commercial product (IDEAS)
• Tp = 800 ns (300 ns – 1000 ns)• no pipeline• 5 MHz readout• 20 Mrad radiation tolerance• noise: ENC = 180 e + 7.5 e/pF• time over threshold: ~2000 ns• single sample per trigger
APV25 (Belle-II SVD)• Developed for CMS by IC
London and RAL• Tp = 50 ns (30 ns – 200 ns)• 192 cells analog pipeline• 40 MHz readout• >100 Mrad radiation tolerance• noise: ENC = 250 e + 36 e/pF• time over threshold: ~160 ns• multiple samples per trigger
possible (Multi-Peak-Mode)
Must minimizecapacitive load !!!
7TWEPP 2009, Christian Irmler (HEPHY Vienna)23 September 2009
Shaping Time and Occupancy
Threshold
Threshold
Tim e over threshold ~ 2000ns (m easured)
Tim e over threshold ~ 160ns (measured)
Sensitive tim e window ~ 20ns
VA1TATp~800ns
APV25Tp~50ns
Pulse shapeprocessingRM S(tm ax)~3ns
Gain ~12.5
Gain ~8
Total gain ~100
• With hit time finding, we can cope with 40-fold increase in luminosity
• For details see poster by Markus Friedl
8TWEPP 2009, Christian Irmler (HEPHY Vienna)23 September 2009
Consequences for SVD Ladder Design
SVD2 ladders:• Up to 3 ganged (concatenated) sensors are read out from the side• Minimization of material budget, as hybrids are outside of acceptance• SNR > 15 with VA1TA, but would be < 10 with APV25
• Ganging of sensors does not work with APV25!
up to 3 gangedsensors
up to 3 gangedsensors
9TWEPP 2009, Christian Irmler (HEPHY Vienna)23 September 2009
Motivation
“Origami” Chip-on-Sensor Concept
Prototype Assembly
Beam Test Performance
Summary & Outlook
10TWEPP 2009, Christian Irmler (HEPHY Vienna)23 September 2009
Origami – Chip-on-Sensor Concept
(readout connections not shown)• Chip-on-sensor concept for double-sided readout
• Flex fan-out pieces wrapped to opposite side (hence “Origami“)• All chips aligned on one side single cooling pipe
Prototype for 4” DSSD(later with 6” sensors)
11TWEPP 2009, Christian Irmler (HEPHY Vienna)23 September 2009
APV25(th inned to 100µm)
zylon ribcooling pipe
DSSDRohacellKapton
Origami – Details
side view
• Thinned readout chips (APV25) on sensor
• Strips of bottom side are connected by flex fanouts wrapped around the edge
• All readout chips are aligned single cooling pipe
• Shortest possible connections high signal-to-noise ratio
zylon rib
APV25 cooling pipe
3-layer kapton hybrid
integrated fanout(or: second metal)
DSSD
single-layer flex wrapped to p-side
Total material budget: 0.72% X0
(cf. 0.48% for conventional readout)
12TWEPP 2009, Christian Irmler (HEPHY Vienna)23 September 2009
Belle-II SVD Layout
0
0
10
1+23
45
6[cm] layers
[cm]
20
-10-20-30 10 20 30 40
• Tentative geometry • New central pixel double-layer using DEPFET• 4 strip layers of 6” DSSDs• Every sensor is read out individually to maintain high SNR
– red: Origami chip-on-sensor concept– green: read out by conventional hybrid (from side)
Double-layer of DEPFET pixels
4 layers of double-sided strip sensors
13TWEPP 2009, Christian Irmler (HEPHY Vienna)23 September 2009
Sketch of the Outermost Ladder (Layer 6)• Composed of 5 x 6” double-sided sensors
• Center sensors have Origami structure
• Edge sensors are conventionally read out from sides
Cooling block (end ring)
Connector (Nanonics)
Structural element (Zylon) Cooling pipe
Flex circuits
Electronics for border sensor
Electronics for border sensor
ca. 60cm
14TWEPP 2009, Christian Irmler (HEPHY Vienna)23 September 2009
Motivation
“Origami” Chip-on-Sensor Concept
Prototype Assembly
Beam Test Performance
Summary & Outlook
15TWEPP 2009, Christian Irmler (HEPHY Vienna)23 September 2009
APV25 Thinning
• One wafer (319 good dies) thinned down from 300 µm to 106 µm and diced by French company EDGETEK / WSI
• Received 314 good dies (5 lost = 98.4% yield)• 16 thinned APVs mounted onto 4 hybrids• Compared to 1 hybrid with 4 standard APVs
Measurement Results:• All APVs show similar signal and noise figure• Proper calibration curve• No measurable differences between normal
and thinned chips
Thinning has no effects on APV functionality and signal quality! APV25 Calibration Curve
Thinned APV25
Standard APV25
16TWEPP 2009, Christian Irmler (HEPHY Vienna)23 September 2009
Origami Hybrid – Final Layout
4 n-side APV chips
2 p-side APV chips 2 p-side APV chips Connectors(on both sides)
Flex fanouts to beWrapped aroundthe sensor edge
• 3-layer flex hybrid design
• p- and n-sides are separated by 80V bias
• n-side pitch adapter is integrated in hybrid
• 3 pcs. of each type produced at CERN PCB workshop
Animal farm (mascots of creators)
17TWEPP 2009, Christian Irmler (HEPHY Vienna)23 September 2009
Module Assembly 1Hamamatsu 4” DSSD:• top side: 152 µm pitch (z)• bottom side: 50 µm pitch (rφ)
• Gluing fanouts onto bottom side:– Custom jig (porous stone inlay) for
gluing and wire bonding– Two component epoxy paste
adhesive Araldite® 2011– Aligning fanouts against sensor and
hybrid– Distance between flexes is
important
• Wire bonding:– Fully automated bonder F&K
Delvotec 6400
• Processing of bottom side is finished
18TWEPP 2009, Christian Irmler (HEPHY Vienna)23 September 2009
bottom APV25
top APV25
APV25 calibration curves of Origami hybrid
Module Assembly 2• Attaching APV25 chips onto hybrid
– Two component conductive adhesive
– Alignment under microscope
• Gluing hybrid onto Rohacell foam– There must be sufficient glue
underneath the bond pads!
• Wire bonding of APV25 power and control lines
• Electrical test of hybrid– some bad vias mostly repaired
with thin wires– Hybrid PCB design is okay– 7 of 8 APV chips are working well– Excellent internal calibration
results
19TWEPP 2009, Christian Irmler (HEPHY Vienna)23 September 2009
Module Assembly 3
• Flip sensor and fanouts – Using another jig jig2– Jigs are stuck together with
3 alignment pins– Turning over– Remove jig1– Further assembling has to be
done on jig2• Gluing hybrid onto top side of
sensor– Aligning pitch adapter to strips
on sensor and fanouts• Wire bonding between sensor
and integrated pitch adaptor
2 openings to protect bottom side bond wires
20TWEPP 2009, Christian Irmler (HEPHY Vienna)23 September 2009
Module Assembly 4
• Bending & Gluing of fanouts– Using positioner equipped
with a custom tool – Easier than expected– Allows precise positioning
w/o damaging underlying wire bonds
• Wire bonding between APVs and pitch adaptors
• Attaching cooling pipe– Thermal conductive paste– Electrically isolating pad
between APV and pipe
21TWEPP 2009, Christian Irmler (HEPHY Vienna)23 September 2009
Final Origami Module
• Origami concept already presented at TWEPP 2008
• Prototype completed beginning of August 2009
22TWEPP 2009, Christian Irmler (HEPHY Vienna)23 September 2009
Motivation
“Origami” Chip-on-Sensor Concept
Prototype Assembly
Beam Test Performance
Summary & Outlook
23TWEPP 2009, Christian Irmler (HEPHY Vienna)23 September 2009
Beam Test Setup
• CERN SPS beam line Aug. 09• 120 GeV π+ / p / K+ • Cooling: 13 °C water
cooling system
beam
• Origami Module• Together with different types of
Belle DSSD prototype modules
24TWEPP 2009, Christian Irmler (HEPHY Vienna)23 September 2009
Beam Test Results• Origami Module has been tested for several hours • Good performance w and w/o cooling (13 °C water)• About 80 GB data recorded• Analysis is in an early stage results preliminary• Benefit of cooling: ~ 10% higher SNR
120 GeV/c π+/p/K+ w/o cooling cooling (13° water)
p-side n-side p-side n-side
Average cluster width 2.2 1.8 2.2 1.8
Cluster SNR 11.5 16.7 12.8 18.5
PreliminaryPreliminary
• Cluster SNR = strip_signal / ( sqrt(cluster_width) * noise_avg)• ~10% higher noise compared to 2008 beam test for all modules
(ground loop in the front-end and / or HV supply?) • Hence SNR of all modules is slightly worse than expected
25TWEPP 2009, Christian Irmler (HEPHY Vienna)23 September 2009
• Time resolution achieved in beam tests with several different types of Belle DSSD prototype modules (covering a broad range of SNR)
Beam Test Results 2
Time Resolution vs. Cluster SNR
0
1
2
3
4
5
6
7
5 10 15 20 25 30
Cluster SNR [1]
trm
s [n
s]Previous beam tests
SPS 09 beam test
Log-Log Fit
(TDC error subtracted)
Origami Module
• SPS 2009 data matches previous beam test.
• 2...3 ns RMS accuracy at typical cluster SNR(15...25)
• Origami shows similar precision like other modules
26TWEPP 2009, Christian Irmler (HEPHY Vienna)23 September 2009
Motivation
“Origami” Chip-on-Sensor Concept
Prototype Assembly
Beam Test Performance
Summary & Outlook
27TWEPP 2009, Christian Irmler (HEPHY Vienna)23 September 2009
• Motivated by KEKB upgrade and Belle II
• Concept for low-mass double-sided readout with cooling
• Thinning of APV25 chips does not affect its functionality
• Successfully built the first prototype of an Origami module
• Module showed excellent performance at beam test
• Beam test analysis is still ongoing
• Next goal: We want to build a prototype of the outermost layer of Belle-II SVD
Summary & Outlook
28TWEPP 2009, Christian Irmler (HEPHY Vienna)23 September 2009
Thank you for your attention
29TWEPP 2009, Christian Irmler (HEPHY Vienna)23 September 2009
BACKUP SLIDES
30TWEPP 2009, Christian Irmler (HEPHY Vienna)23 September 2009
Origami Material Budget
• X0 comparison between conventional and chip-on-sensor:
Conventional (double layer kapton)
Layer Material X0 [mm] Thickness [mm] Percentage Area coverage Averaged PercentageSensor Silicon 93.7 0.3 0.32% 100.0% 0.320%Fanout Polyimide (2 layer of 50um each) 300.0 0.1 0.03% 96.3% 0.032%
Copper (10um) 14.0 0.01 0.07% 50.0% 0.036%Nickel (top: 1.3um) 14.3 0.0013 0.01% 50.0% 0.005%Gold (top: 0.8um) 3.4 0.0008 0.02% 50.0% 0.012%
Ribs Zylon (0.5mm wide) 300.0 5 1.67% 3.7% 0.062%Glue Araldite 2011 / Double sided tape 335.0 0.05 0.01% 96.3% 0.014%
Total 0.480%
DSSD Chip-on-Sensor (4-layer kapton)
Layer Material X0 [mm] Thickness [mm] Percentage Area coverage Averaged PercentageSensor Silicon 93.7 0.3 0.32% 100.0% 0.320%Isolation Rohacell (Degussa) 5450.0 1 0.02% 96.3% 0.018%Hybrid Polyimide (4 layers of 50um each) 300.0 0.2 0.07% 96.3% 0.064%
Copper (4 layers of 5um each) 14.0 0.02 0.14% 64.7% 0.092%Nickel (top: 1.3um) 14.3 0.0013 0.01% 64.7% 0.006%Flash Gold (top: 0.4um) 3.4 0.0004 0.01% 64.7% 0.008%
Flexes Polyimide (1 layer of 25um) 300.0 0.025 0.01% 56.3% 0.005%Copper (1 layer of 5um) 14.0 0.005 0.04% 28.1% 0.010%Nickel (top: 1.3um) 14.3 0.0013 0.01% 28.1% 0.003%Flash Gold (top: 0.4um) 3.4 0.0004 0.01% 28.1% 0.003%
8 * APV25 Silicon 93.7 0.1 0.11% 21.4% 0.023%SMDs SMD 50.0 0.4 0.80% 0.8% 0.007%Sil-Pad Sil-Pad 800 (Bergquist) 200.0 0.127 0.06% 11% 0.007%Pipe Aluminum (D=2.0mm, wall=0.2mm) 89.0 0.56 0.63% 7% 0.047%Rib Zylon (0.5mm wide) 300.0 5 1.67% 1.9% 0.031%Glue Araldite 2011 335.0 0.2 0.06% 50% 0.030%Cooling Water 360.5 1.26 0.35% 13% 0.047%
Total 0.719%
• +50% increase in material, but also huge improvement in SNR• Trade-off between material budget and SNR• According to simulation, additional material is prohibitive in
innermost layer, but no problem for layers 4-6 OK with layout
31TWEPP 2009, Christian Irmler (HEPHY Vienna)23 September 2009
Origami Hybrid – Flexes