LHCb VELO Hybrid T Bowcock University of Liverpool

LHCb VELO Hybrid T. Bowcock University of Liverpool

LHCb Vertex Locator

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

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

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

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

Prototype Problems n n “Bad” design… Lineup of Fanouts and sensor Angles of pads Two types of sensor w 2 or more sets of fanouts w Sensor pads cannot be made the same

2003 Prototype Beetle 1. 2/1. 3 Substrate n n n 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 160 um so the effective pitch for the four row bonding is 40 um 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 40 um tracks and gaps on each layer. the bottom layer protrudes out from under the top layer by about 400 um. 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 n Dage Class 100 n 100 m 2

Bonding Lengths up to 3 mm n Fanout to Sensor: TO BE IMPROVED 17 micron Al wire Height Difference ~ 0. 5 mm Smallest Pitch dominated by Beetle Multi-loop height Wire pull tests n Strengths >6 g

Problems Expected Fabrication of solid substrate/kapton that does not delaminate n n Flatness (helps bonding) Quality of bonding Jig for Double Sided Bonding n Non-trivial Pattern Recognition and Programming of 8090. Bonding on arc. n Problem solved. Memory + Shipping Optimisation of Pad Layout n Avoid foot being skewed relative to pads

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