Transcript LHCb VELO Hybrid

LHCb VELO Hybrid
T. Bowcock
University of Liverpool
LHCb Vertex Locator
Silicon Module
Components
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Sensors
Substrate
Hybrid
Cooling
Paddle
Base
Cables
Module-0 ‘04
Silicon Modules
50 modules
Approximately 500,000 bonds
Operation at –5C
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Thermal issues over assembly at 21C
Vacuum
Movement several times a day
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But very small magnetic field
Silicon Module
Double Sided Module
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Modification from TDR
Two hybrids on one substrate
Symmetry
Mass
Difficult to fabricate and bond
Substrate
CF encapsulated
TPG
Thermal
conductivity
Mass
Big relative CTE
to kapton
Module Assembly
All glued
Combination of film and robot
dispensed glue
Test of procedures for vacuum
operation
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Removing air VERY important
How do we stop glue oozing out through
holes (kapton), edges?
Prototype
2002 prototype
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Bonded with SCTVELO chips
Single Sided(!)
K&S 8090 pattern
recognition
Sensors
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150-300microns
Kapton and Fanouts
Glass Fanouts
at CERN
Prototype
Problems
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“Bad” design…
Lineup of Fanouts and
sensor
Angles of pads
Two types of sensor
 2 or more sets of fanouts
 Sensor pads cannot be
made the same
2003 Prototype
Beetle 1.2/1.3
Substrate
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Lamination
“Bounce”
Jig
Flatness
Double Sided
Kapton fanouts
Beetle 1.2 5100  6100m – chip is very small
4 row
bonding
Row to row centres
are 150 um.
Pitchwithin a row
is
160um so the
effective pitch
for the four row
bonding is 40um
Pads 120  95m
SMALL
Pads at angle to
Fanout?
Sensor Pads
under design
and review
Straight Line?
Circle?
Proposed Fanouts
The fanouts have two metal layers
pitch at the beetle end is the tightest with 40um
tracks and gaps on each layer.
the bottom layer protrudes out from under the top
layer by about 400um.
For four row bonding the two rows of beetle pads
nearest the edge of the chip bond to the lower
copper layer and the two other rows bond to the top
copper layer
The copper is coated with nickel and flash gold.
Liverpool Semiconductor Centre
K&S 8090
H&K 710(2)
Wirepull
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Dage
Class 100
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100m2
Bonding
Lengths up to 3mm
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Fanout to Sensor: TO BE IMPROVED
17micron Al wire
Height Difference ~ 0.5mm
Smallest Pitch dominated by Beetle
Multi-loop height
Wire pull tests
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Strengths >6g
Problems Expected
Fabrication of solid substrate/kapton that
does not delaminate
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Flatness (helps bonding)
Quality of bonding
Jig for Double Sided Bonding
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Non-trivial
Pattern Recognition and Programming of
8090. Bonding on arc.
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Problem solved. Memory + Shipping
Optimisation of Pad Layout
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Avoid foot being skewed relative to pads
Problems
We cannot afford to test at the same
level as ATLAS/CMS
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cycling, radiation damage etc
Procedures have to be right
20 modules = 50% of the production!
Need to learn from ATLAS,CMS,+…