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

LHCb Vertex Locator

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

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

Silicon Module Double Sided Module 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 Removing air VERY important How do we stop glue oozing out through holes (kapton), edges?

Prototype 2002 prototype Sensors Kapton and Fanouts at CERN Bonded with SCT-VELO chips Single Sided(!) K&S 8090 pattern recognition Sensors 150-300microns Kapton and Fanouts at CERN Glass Fanouts

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

2003 Prototype Beetle 1.2/1.3 Substrate Kapton fanouts 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 Dage Class 100 100m2

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

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 8090. Bonding on arc. Problem solved. Memory + Shipping Optimisation of Pad Layout Avoid foot being skewed relative to pads

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,+…