Two versions went for manufacture – test vehicle for tab and solder resist evaluation

1. ABC130 Thermo-mechanicals • Two versions went for manufacture – test vehicle for tab and solder resist evaluation • Trying to improve planarity of circuits • Circuit build is identical to the electrical version – when submitted • 3 layers, 18µm Cu using 50µm dielectric (polyimide) with 150µm blind vias • Circuits identical except for use of differing solder resists: • One batch made with ‘standard’ rigid resist (as presently used on ABCN-25 hybrids) • Second batch made with flexible resist • Received 5 panels of each – 80 circuits total (40 of each flavour) • Quality looks very good • Panels and hybrids are very flat and first pass with tooling shows nothing untoward • Anecdotal evidence to suggest that shrinkage control has further improved • Comes from trying tooling – will confirm their geometry next week on SmartScope • Hybrid thickness is ~265µm and weigh 1.30g • Present ABCN-25 hybrids come in at ~260µm and weigh 1.65g • Build thicknesses similar due to use of 18/50/18 Cu-Clad carriers on new circuits • ‘Old’ hybrids used thinner carrier for outer layers but 18/50/18 for inner layers • 3 layer build contributes to weight reduction (less Cu)

2. ABC130 Thermo-mechanicals HCC heat load Digital Thermometer NTC • On-hybrid temperature monitoring using either • 1-wire digital thermometer (DS18B20, -55ºC to +125ºC range with 12 bit resolution) • NTC (1kΩ at 25ºC) • Both circuits accessible via bond field towards end of hybrid • Resistive elements used to emulate asic heat loads • Embedded trace for ABC130 - leaves lands clear for dummy asic placement (tooling evaluation) • Design specification was ~230mΩ /asic • Measured resistance is higher – see next slide • SMD resistors for HCC • One circuit evaluated using thermal imaging camera – looked very uniform • Tim Jones has data...

3. ABC130 Thermo-mechanicals Resistance measured for 8 hybrids (80 asics) Resistance measured for all hybrids Standard Resist Flexible Resist Standard Resist Flexible Resist • Clearly 2 families of resistance • Both batches processed at differing times • No evidence of over-etching, difference probably due to differing Cu weights • Expected resistance ~280mΩ/asic, measured: • Standard resist: ~364mΩ/asic (σ ~ 3.67mΩ) • Flexible resist: ~400mΩ/asic (σ ~ 3.75mΩ) • ‘asics’ linked up serially (likewise hybrids...) • For ~5W dissipation/module will require ~6V/module and ~80V/Stave side • Within the “Extra Low Voltage” regime for safety (<120V DC) ~1% spread