1. T. Bowcock University of Liverpool
LHCb VELO Hybrid
T. Bowcock University of Liverpool

2. LHCb Vertex Locator

3. Silicon Module Components Module-0 ‘04 Sensors Substrate Hybrid
Cooling
Paddle
Base
Cables
Module-0 ‘04

4. Silicon Modules 50 modules Approximately 500,000 bonds
Operation at –5C
Thermal issues over assembly at 21C
Vacuum
Movement several times a day
But very small magnetic field

5. Silicon Module Double Sided Module Modification from TDR
Two hybrids on one substrate
Symmetry
Mass
Difficult to fabricate and bond

6. Substrate CF encapsulated TPG Thermal conductivity Mass
Big relative CTE to kapton

7. Module Assembly All glued Combination of film and robot dispensed glue
Test of procedures for vacuum operation
Removing air VERY important
How do we stop glue oozing out through holes (kapton), edges?

8. Prototype 2002 prototype Sensors Kapton and Fanouts at CERN
Bonded with SCT-VELO chips
Single Sided(!)
K&S 8090 pattern recognition
Sensors
microns
Kapton and Fanouts at CERN
Glass Fanouts

9. Prototype Problems “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

10. 2003 Prototype Beetle 1.2/1.3 Substrate Kapton fanouts Lamination
“Bounce”
Jig
Flatness
Double Sided
Kapton fanouts

12. 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

15. Pads at angle to Fanout?
Sensor Pads under design and review
Straight Line?
Circle?

16. 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.

17. Liverpool Semiconductor Centre
K&S 8090
H&K 710(2)
Wirepull
Dage
Class 100
100m2

18. Bonding Lengths up to 3mm 17micron Al wire Height Difference ~ 0.5mm
Fanout to Sensor: TO BE IMPROVED
17micron Al wire
Height Difference ~ 0.5mm
Smallest Pitch dominated by Beetle
Multi-loop height
Wire pull tests
Strengths >6g

19. Problems Expected
Fabrication of solid substrate/kapton that does not delaminate
Flatness (helps bonding)
Quality of bonding
Jig for Double Sided Bonding
Non-trivial
Pattern Recognition and Programming of Bonding on arc.
Problem solved. Memory + Shipping
Optimisation of Pad Layout
Avoid foot being skewed relative to pads

20. Problems We cannot afford to test at the same level as ATLAS/CMS
cycling, radiation damage etc
Procedures have to be right
20 modules = 50% of the production!
Need to learn from ATLAS,CMS,+…