WP6 meeting 30/07/2013

Status of flex prototypes production New laser soldering tests Discussion on mass production schedule

Flex prototypes FHR order: 2 foils with 3 circuits, 25  m apical from Rui (obtained removing Cu layers bu chemical etching) + 15  m Al (compatible with chemical etching procedure at CERN), issue on first foil coated (Al peels off at the edge) due to bad quality of apical? Next: another test using 50  m apical from FHR and15  m Al + 2 foils coated with 25  m Al Goals: 1) check chemical and laser etching on two Al thickness; 2) electrical tests Delivered ….

Differential impedance simulations

New laser soldering tests Test performed at Neu Ulm not conclusive, issues with: – soldering grid design – Single chip flex: holes too small (160  m), metallisation? – Small SnAg balls (200  m) Laser soldering system rented at Dr Mergenthaler to optimize parameters (temperature profile, beam focusing) System to be installed in DSF, safety requirements to be verified next week with laser safety officer (actions for DSF?) Aim at starting at the beginning of September

Single chip flex, w/o coverlay, no soldering grid

Issues: -Mismatch between microscope and metallurgy pictures numbering -Most of solderings does not wet the chip pad Single chip flex, w/o coverlay, no soldering grid

Planning of staves assembly Inner barrel – 48 staves x % ~ 110 staves – 990 chips, solderings Outer barrel – 1602 modules +10% ~ 1800 modules – chips, solderings

Planning of staves assembly Assembly sequence hypothesis: 1)Placement of chips on vacuum table (auto): 9x10” ~ 90” (14 chips: 140”) 2)Placement of flex on vacuum table + grid on flex (man, pinholes): 300” 3)Alignment (auto): 300” 4)SnAg balls deposition + soldering of one chip (auto): 300” + 50x 10”= 800” Total per IB module: 2h 11’ -> 30 d for full IB Total per OB module: 3h 19’ -> ~ 750 d for full OB (1 d = 8h)

Planning for Layers 0, 1, 2, 3 and 4

Short term plans (for TDR final version) By the end of September: – Preliminary results on technology for Al flex production, chemical vs laser engraving – Preliminary results on chips embedding – Laser soldering: optimization of process parameters, tooling Critical issues – Design of flex depends on chips specs not available (i.e. power consumption: if 25 mW/cm 2 instead of 250 mW/cm 2 less constraints on Al thickness?) – Al flex processing dependence on Al layer thickness – Study of electrical characterization/ performance of flex