m. gilchriese local support r&d update atlas pixel upgrade meeting april 9, 2008 m. cepeda, s....
TRANSCRIPT
M. Gilchriese
Local Support R&D UpdateATLAS Pixel Upgrade Meeting
April 9, 2008M. Cepeda, S. Dardin, M. Garcia-Sciveres, M. Gilchriese and R. Post
LBNLW. Miller and W. Miller
iTiC. Daly, B. Kuykendall, H. Lubatti
University of Washington
M. Gilchriese2
Module Dimensions for Studies
• Have defined multi-chip and single-chip dimensions(two alternatives) as basis for studies.
• Assumption is that multi-chip used for outer layers and single-chip used for innermost layer(s). Exact break in radius is TBD.
• See backup for more information• Also basis for understanding possible cost reductions in bump deposition
and flip-chip (not discussed here)
34.8
34.8
37.5
Active 32.8 x 32.8
10.0
15.0Flex pigtail (connector plugs into page)
Pixel orientation
Flex down to chip w-bonds
0.2
(vertical inter-chip gap 0.1mm)
Optimize module size assuming6” planar sensor wafers
M. Gilchriese3
Outer Stave Concept• Staves for outer barrel layers for multi-chip modules.
• Based on foam, thin carbon-fiber facings AND flex-cable laminated to stave under modules (bus-cable)
• Bus-cable routes power, signals, HV to end-of-stave cards. Studies started to see if this works electrically.
• Bus-cable worst case thermally
• If bus-cable concept bad…revert to “Type I cables”
• Modules on both sides (staggered for coverage)
• Connector from module to connector on bus-cable
• Dimensions shown for CO2(thicker for C3F8)
CARBON FOAM
M. Gilchriese4
Outer Layer Layout Example
M. Gilchriese5
Double-Outer Layer Concept
• Support two outer layers of staves from single shell?
• Doesn’t look impossible
• Obviously lots of details……
Composite shell and inner support rings combine assembly into one unit
M. Gilchriese6
Sensors Heating• From Dawson et al. (radiation task force) and temperature
parameterization of Unno
• Figure is for 6000 fb-1
• Table except 1016 assumes 6000 fb-1. Short strips are at about 30 cm
• W/cm2 shown in table
TShort-StripPower
Pixel@16 cm
Pixel@21 cm
Pixel@1e16
-35 0.001628 0.003039 0.002195 0.016886-30 0.003145 0.005871 0.00424 0.032619-25 0.005922 0.011054 0.007983 0.06141-20 0.010882 0.020312 0.01467 0.112847-15 0.019545 0.036484 0.02635 0.202691-10 0.034358 0.064136 0.04632 0.35631-5 0.059183 0.110474 0.079787 0.6137450 0.1 0.186667 0.134815 1.0370375 0.16592 0.309717 0.223684 1.720649
10 0.270584 0.50509 0.364787 2.806054
M. Gilchriese7
FEA Thermal ModelFEA Thermal Model• Pixel Arrangement
– Modules alternate top to bottom, total 5 modules
– Take an array of 3 on top to obtain reasonable symmetry in heat spreading for middle module, leaving two on the bottom
VG VG 77
Inputs for thermal runaway calculations
0
20
40
60
80
100
120
-35 -25 -15 -5 5 15 25 35
Sensor peak surface temperature -(C)
Hea
ting
mW
/mm
2
Surface heating16cm radius
Surface heatingfrom 1E16 fluence
M. Gilchriese8
Pixel Thermal Model-BaselinePixel Thermal Model-Baseline
• Thermal Solution– Carbon foam core K=6W/mK
• Peak Differential Temperature Center Module– 7.63ºC
VG VG 88
Cooling Tube Inner Wall Reference Temperature 0ºC
M. Gilchriese9
Thermal Performance - I• Include detector heating (worst case shown is for total fluence of about 1016.
Best case shown is for R ~ 16 cm(and 6000 fb-1).
• “Baseline” parameters assumed in thermal model – see backup
• Looks promising for outer layers. Need higher K’s for 1016 (see next page) unless assume colder fluid(<-30) than current C3F8
Remember needto include effectof T frompressure drops
-30
-25
-20
-15
-10
-5
0
5
10
15
20
25
30
-40 -35 -30 -25 -20 -15 -10 -5 0
Coolant Tube Inner Wall Temperature-(C)
Pe
ak
Se
ns
or
Te
mp
era
ture
-(C
)
no surface heating1.87mW/mm2 @ 0 C10.67mW/mm2 @ 0 C
M. Gilchriese10
Thermal Performance - II• Results below all for 1016 fluence and changes in stave-component K
values.
• Need to optimize for 1016. Different designs for inner(most) and outer layers
• Unless CO2. Note CO2 also significantly lower in radiation length
Higher K foamCarbon-carbon facingsCVD diamond facingsNo bus cableCombinations…..
Note that these studies alsoapply to 2cm wide stavewith single pipe that is more likely at innermost R -35
-30
-25
-20
-15
-10
-5
0
5
10
-35 -30 -25 -20 -15 -10 -5 0
Coolant Tube Inner Wall Temperature-(C)
Pe
ak
Se
ns
or
Te
mp
era
ture
-(C
)
baseline foam 6 W/mK
foam=15W/mK
foam=15W/mK, CC=250/25/250
foam=15W/mK, Cable=200W/mK
M. Gilchriese11
Pixel Monolithic StructurePixel Monolithic Structure
VG VG 1111
Alternating: Inner and Outer Layer
Older module dimensions used for this study
M. Gilchriese12
Thermal FEA-Based on 0.6W/cmThermal FEA-Based on 0.6W/cm22
VG VG 1212
Differential from silicon to coolant wall is 10.6˚C. Need improvement to prevent thermal runaway with C3F8….to be studied
Foam K=10 W/mK
M. Gilchriese13
Thermally Conducting Foam Update• Obtained additional foam samples – three vendors
• Made additional small thermal prototypes and measured (see backup for details). Preliminary results.
Foam (g/cc) K(W/m-K) Tmax
Allcomp 1 0.18 ~ 6We measured
~ 10
Allcomp 2 0.21 Not known ~ 9
POCO 0.09 ~ 17(z)
~ 6(x-y)Vendor supplied
~ 11
Koppers* 0.21 ~ 30(z?)Vendor supplied
~ 8
Averagemax at 0.64W/cm2 on one side
* Have 2 other higher density and K samples from Koppers
Old prototype, shown last meeting
New
res
ults
, ne
w s
amp
les
M. Gilchriese14
Foam Mechanical Properties
• Important to measure mechanical properties of foam
• Being done at University of Washington• Allcomp 1 results – see presentation at meeting link at
http://phyweb.lbl.gov/atlaswiki/index.php?title=ATLAS_Upgrade_RandD_-_Mechanical_Studies#Pixel_Upgrade_Support.2FCooling_Structure_Studies
M. Gilchriese15
Outlook
• Optimize thermal performance, radiation length, mechanical properties combining foam(s), facing materials and support. Likely to result in different inner and outer staves. Monolithic still option for innermost layer.
• Biggest impact on radiation length is choice of coolant…
• Starting on disks. Layout not as easy as barrel…..particularly in case of two-part system, one inside support tube
• Overall layout issues and electrical interfaces that drive layout – started some work on this (with UCSC, SLAC, OSU, SMU..)
• Thermally conducting, carbon foam continues to look promising. Multiple vendors interested (are there more?). Need to optimize and get more samples of what we want. Vendors willing to develop lower density.
M. Gilchriese
Backup
M. Gilchriese
2x2 module & stave layouts
M. Garcia-Sciveres
M. Gilchriese18
2 options• “Small chip”• “Big chip”• Boundary between “small” and “big” is determined by the 6” sensor wafer layout
that must be compatible with bump bonding (will become clear later)• “Small” chip has also a more natural number of rows & columns, but this is
probably a minor issue for chip design.
M. Gilchriese19
Parameters
# cols total # rows total # ganged rows
# long cols Long col width
Small chip 64 324 0 0 0
Small 2x2 tile 128 654 6 4 450um
Small active edge
1x1 tile
64 324 0 2 450um
big chip 70 348 0 0 0
big 2x2 tile 140 702 6 4 450um
big active edge
1x1 tile
70 348 0 2 450um
Normal col. width x row height = 250um x 50um
M. Gilchriese20
“Small” 4-chip module
34.8
34.8
37.5
Active 32.8 x 32.8
10.0
15.0Flex pigtail (connector plugs into page)
Pixel orientation
Flex down to chip w-bonds
0.2
(vertical inter-chip gap 0.1mm)
M. Gilchriese21
“Big” 4-chip module
37.1
37.8
39.9
Active 35.8 x 35.1
10.0
15.0Flex pigtail (connector plugs into page)
Pixel orientation
Flex down to chip w-bonds
0.2
(vertical inter-chip gap 0.1mm)
M. Gilchriese22
Loaded module
20 position connector would be used. Replace 10.22 dimension by 6.52
glue
chips
sensorflex
conn
ecto
rReduced scale
1.0
mm
stiffener
M. Gilchriese23
“Small” module outer stave
…
End of stave card serving 8 modules (half a stave) along ZCan serve one face only (top or bottom) => 4 cards per staveOr can be a wrap-around end of stave card and serve both faces => 2 cards per stave.This way identical staves (including bus cable) design can be used over a wide radial range: 4 cards/stave at lower radius and 2 wrap-around cards per stave at higher radius
34.8 26.8
Module on back
986mm
38.4
M. Gilchriese24
“Big” module outer stave
…
End of stave card serving 7 modules (half a stave) along Z (or 8 modules for 1082mm active length)
Can serve one face only (top or bottom) => 4 cards per staveOr can be a wrap-around end of stave card and serve both faces => 2 cards per stave.This way identical staves (including bus cable) design can be used over a wide radial range: 4 cards/stave at lower radius and 2 wrap-around cards per stave at higher radius
37.8 29.8
Module on back
946mm
39.9
M. Gilchriese25
“Small” sensor 6 inch wafer
• Active area = 7508 mm^2
• Sensor tiles shown with darker line
• Wafer scale flip chip compatible. Chips shown with lighter line.
• The name “small” 2x2 tile comes from the wafer layout.
– A slightly larger chip and therefore larger 2x2 tile is possible, but only 6 such “large” 2x2 tiles will fit on a 6” wafer.
M. Gilchriese26
“Big” sensor 6 inch wafer
• Active area = 7539 mm^2• Sensor tiles shown with darker line
• Wafer scale flip chip compatible. Chips shown
with lighter line.
• OPTION to make 4 6-chip modules per wafer instead of 6 4-chip modules.
M. Gilchriese27
“Small” single chip module
• Using same chip as 4-chip module (hence “small”)• Active edge sensor• 2-side abuttable format
16.4
16.2
16.218.7
active
M. Gilchriese28
“Big” single chip module
• Using same chip as 4-chip module (hence “small”)• Active edge sensor• 2-side abuttable format
17.9
17.7
17.419.9
active
M. Gilchriese
Stave Concepts and FEA
W. Miller and W. Miller
M. Gilchriese30 VG VG 3030
Pixel ActivitiesPixel Activities• Analysis Analysis
– Analyze foam structure for inner Pixel Layer steady state chip heating Analyze foam structure for inner Pixel Layer steady state chip heating and thermal runawayand thermal runaway
• Thermal runaway evaluation covers different foam and facing thermal Thermal runaway evaluation covers different foam and facing thermal conductivitiesconductivities
• Design LayoutDesign Layout– Preliminary stages of evaluating packaging for layers at 16cm and Preliminary stages of evaluating packaging for layers at 16cm and
21cm radius21cm radius
• TestingTesting– Thermal solutions to compare with LBNL stave/carbon foam core Thermal solutions to compare with LBNL stave/carbon foam core
thermal teststhermal tests• Evaluation embraces several foam core thermal conductivities Evaluation embraces several foam core thermal conductivities
M. Gilchriese31
Pixel Stave Structure
• Stave Analysis- 1 meter length– In the near future an effort will be underway to assess structural aspects
of stave concept for pixels• For now focusing on thermal effects
– Pixel sensor is 34.85 mm by 34.85 mm
– Pixel chip footprint, 4 total, is 38.4 mm by 38.4mm
– Assumed pixel heat load is 0.6W/cm2
– Small diameter cooling tube (presumes CO2)
• Steps in process– 1st Order thermal analysis of sandwich structure (conductive carbon
foam core)
– Several solutions made for thermal runaway• Looks workable without CVD diamond sandwich facings
– This model is still being evaluated
M. Gilchriese32
Basic Model Parameters-Baseline• Core
– Carbon foam, 6 W/mK
• Facing– Resin Composite, 0.14mm thick, 110, 1, 110 (X,Y,Z) W/mK
• Cable– Includes adhesive for bonding to chips and from cable to composite facing
– 2mils Al and 0.7mils of copper, plus adhesives, total compressed thickness=114microns
– Calculated: Kt=0.38W/mK and K (in-plane)=83W/mK 34.85
34.85
38.4
Sensor Chip heat 0.6W/cm2
M. Gilchriese33
FEA Thermal ModelFEA Thermal Model• Pixel Arrangement
– Modules alternate top to bottom, total 5 modules
– Take an array of 3 on top to obtain reasonable symmetry in heat spreading for middle module, leaving two on the bottom
VG VG 3333
Inputs for thermal runaway calculations
0
20
40
60
80
100
120
-35 -25 -15 -5 5 15 25 35
Sensor peak surface temperature -(C)
Hea
ting
mW
/mm
2
Surface heating16cm radius
Surface heatingfrom 1E16 fluence
M. Gilchriese34
Pixel Thermal Model-BaselinePixel Thermal Model-Baseline
• Thermal Solution– Carbon foam core K=6W/mK
• Peak Differential Temperature Center Module– 7.63ºC
VG VG 3434
Cooling Tube Inner Wall Reference Temperature 0ºC
M. Gilchriese35
Pixel Thermal ModelPixel Thermal Model
• Thermal Solution– Carbon foam core K=100W/mK
• Peak Differential Temperature Center Module– 4.05ºC
VG VG 3535
Very High Foam Conductivity alters peak differential by 3.58ºC
M. Gilchriese36
Thermal Runaway-Baseline
1*1016 fluence makes -25ºC impractical without design changes to sandwich material maheup
-30
-25
-20
-15
-10
-5
0
5
10
15
20
25
30
-40 -35 -30 -25 -20 -15 -10 -5 0
Coolant Tube Inner Wall Temperature-(C)
Pe
ak
Se
ns
or
Te
mp
era
ture
-(C
)
no surface heating1.87mW/mm2 @ 0 C10.67mW/mm2 @ 0 C
M. Gilchriese37
Thermal Runaway with Possible Mod’s
• Results show increasing conductivity of foam and facing thermal conductivity improve situation noticeably
• Thermal solution with CVD diamond facing still under evaluation, all indications is that it may be overkill
Fluence of 1*1016
-35
-30
-25
-20
-15
-10
-5
0
5
10
-35 -30 -25 -20 -15 -10 -5 0
Coolant Tube Inner Wall Temperature-(C)
Pe
ak
Se
ns
or
Te
mp
era
ture
-(C
)
baseline foam 6 W/mK
foam=15W/mK
foam=15W/mK, CC=250/25/250
foam=15W/mK, Cable=200W/mK
M. Gilchriese38
Design Layouts-In Process
• Beginnings of 210mm and 160mm layers
Composite shell and inner support rings combine assembly into one unit
M. Gilchriese39
Design Layouts-In Process
• Space between adjacent staves is very tight, suggesting that the stave support from the rings may best engage area between module dead-spaces
M. Gilchriese40
Design Layouts-In Process• First option for 1m length is three support rings, one in middle which
will provide the Z-restraint and the two at the ends reacting out gravitational effects, but allowing slip in Z
Ring locations
M. Gilchriese41
Carbon Foam Thermal TestsCarbon Foam Thermal Tests
• Following slides provide background on carbon foam thermal Following slides provide background on carbon foam thermal conductivityconductivity
VG VG 4141
M. Gilchriese42 VG VG 4242
FEA ModelFEA Model
• Primary ObjectivePrimary Objective– Compare FEA results with LBNL thermal tests of foam core structuresCompare FEA results with LBNL thermal tests of foam core structures
• Difficulty lies in assigning material propertiesDifficulty lies in assigning material properties– There are four solids, with three thermal interfaces on each side of the mid-planeThere are four solids, with three thermal interfaces on each side of the mid-plane
• Thermal interface thermal resistance becomes an assumption, as well as the thicknessThermal interface thermal resistance becomes an assumption, as well as the thickness
– Water coolantWater coolant• Flow results in turbulent flow and very high convection coefficient, less problematic Flow results in turbulent flow and very high convection coefficient, less problematic
than thermal interface resistancethan thermal interface resistance• Expect small variations in coolant temperature from test to testExpect small variations in coolant temperature from test to test
M. Gilchriese43 VG VG 4343
Solution With FEA ModelSolution With FEA Model• Material PropertiesMaterial Properties
– Heater heat loads, 8.38WHeater heat loads, 8.38W
– Silicon heater, 148 W/mK, 0.28mm thickSilicon heater, 148 W/mK, 0.28mm thick
– Silicon heater adhesive, SE4445, 0.6 W/mK, 0.004in thick, two placesSilicon heater adhesive, SE4445, 0.6 W/mK, 0.004in thick, two places
– YSH70 open cloth fabric, one layer, 0.6 W/mK, 0.14mmYSH70 open cloth fabric, one layer, 0.6 W/mK, 0.14mm
– YSH70 adhesive, 1.55 W/mK, 0.002inYSH70 adhesive, 1.55 W/mK, 0.002in
– Foam properties varied, from 6 to 30 W/mKFoam properties varied, from 6 to 30 W/mK
– Al cooling tube, 180 W/mK, 2.8mm OD and 2.19mm IDAl cooling tube, 180 W/mK, 2.8mm OD and 2.19mm ID
– Water, convective film coefficient, 66,000 W/mWater, convective film coefficient, 66,000 W/m22K, 1.0L/minK, 1.0L/min• Set 20.25ºC on inner tube wallSet 20.25ºC on inner tube wall
– K13D2U facing, 1 W/mK, 0.28mm thickK13D2U facing, 1 W/mK, 0.28mm thick
– K13D2U adhesive, 1.55 W/mK, 0.002in thick K13D2U adhesive, 1.55 W/mK, 0.002in thick
M. Gilchriese44 VG VG 4444
Pixel Prototype ComponentsPixel Prototype Components
Tube with CGL7018
YSH-70 and K13D2U glued to foam
Tube in foam with CGL7018
M. Gilchriese45 VG VG 4545
LBNL Thermal Test Set-UpLBNL Thermal Test Set-Up
Silicon heater
M. Gilchriese46
Thermal Solutions for Single Tube Tests
Double heater Single heater
M. Gilchriese
Prototype Details
M. Gilchriese48
Old Results
0
2
4
6
8
10
12
14
16
0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70
P/A(W/cm^2)
De
lta
T a
ve
rag
e
YSH-70 only
K13D2U only
YSH-70 sideHeat both
K13D2U sideHeat both
Note if CO2 used as coolantthen reference temperature could be about -30C. Thusdelta T of 10 => T of -20C.
FE
-I4
goal
FE
-I3
norm
al
Max
. sp
ecIncludes sensors & power conv. But not cables.
M. Gilchriese49
Old Results Table
• All relative to 20C water temperature, would be slightly lower if referenced to power off temperature.
P/A(W/cm2) YSH-70 only K13D2U only
YSH-70 sideHeat both
K13D2U sideHeat both
0.64 11.20.44 7.40.28 50.64 11.050.44 7.450.28 5.250.64 14.4 14.450.44 9.9 10.150.28 6.35 6.52
M. Gilchriese50
New Prototypes• Identical width, thickness and adhesives to older prototype
(Allcomp 1) but shorter in length (7.4 cm).
• YSH-70 facings on both sides.
• Heater only on one side. Compare at 0.64 W/cm2
• IR and water flow same as older prototoype(1.0 l/min)
M. Gilchriese51
IR Results• Example IR photo(Koppers)• Average T in boxes used• Small difference between power off T
and water T
Two different values for Allcomp 2 in table below. One(29 twice) I ignore apparent hot spot on heater. Other entry I don’t.Sample T Av Water T1(0 pwr) T2(0 pwr) T1(0.64) T2(0.64) DT(to water) DT(to 0 pwr)Allcomp 1 20.1 20.85 20.78 30.65 30.71 10.6 9.9Allcomp 2 20.05 20.41 20.44 29 29 9.0 8.6Allcomp 2 20.05 20.41 20.44 29 30.91 9.9 9.5POCO 20.15 20.84 20.83 31.48 32.66 11.9 11.2Koppers 20.2 20.63 20.6 28.92 29.2 8.9 8.4