WP3_Bham; 10July 2014; John Wilson1 Gluing: more investigations (Simon and Sam) New clamping method provides a good base for systematic studies. Sketch out the 5-dot patterns expected from the stencil. Is this achieved? Measure 5-dot patterns after gluing on glass ASICs Measure the 5-dot patterns on hybrids after shearing 1

WP3_Bham; 10July 2014; John Wilson2 Stencil Symmetric 5 dot pattern: 2mm diameter, centres separated by 1.91mm. Rectangular ASIC: 7.9mm x 6.7mm Area of dots = 30% ASIC surface a b c a = 1.05; b = 0.44; c = 0.70

WP3_Bham; 10July 2014; John Wilson3 5dot patterns (old clamping); cured on glass ASICs (measured on Mech Eng optical bench) Each dot has a distinct rim; plateau diameter < 2.0 mm; significant bleeding beyond diam of 2.0 mm

WP3_Bham; 10July 2014; John Wilson4 Profiles of cured glue dots (old clamping) Expected stencil dot Far too much glue Very non- uniform

WP3_Bham; 10July 2014; John Wilson5 Cured 5-dot patterns on glass ASICs (New clamping) Well delineated dots: diam of plateau ~1.7 mm; diam of base ~ 2.0 mm) (stencil hole = 2.0mm) Repeat measurements at Mech Eng.

WP3_Bham; 10July 2014; John Wilson6 5-dot patterns; effect of cleaning? 6 On glass ASICs – 5 dot pattern, roughly as expected 5 dot glue marks on hybrids, cleaned with isopropanol. 5 dot glue marks on hybrids, cleaned with Safewash. Glue dots smaller than on ASICs Sometimes glue has hardly marked the hybrid – but the shear strength exceeds 5kg! After shear testing

WP3_Bham; 10July 2014; John Wilson7

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10 Summary so far New clamping method has led to a consistent reproducible 5 dot pattern. Shear strength is satisfactory ( > 5kg). But observed 5 dot patterns are not quite as expected from the stencil shape. In particular, the glue often does not seem to have wet the hybrid i.e. the glue shears off the hybrids leaving well less than the expected dot size. Cleaning very important? Measurements on glass ASICs of 5 dot patterns on Mech Eng optical measuring machine inconclusive – amount of glue appears to be larger than the volume of the stencil dot! Will repeat with new clamping sample. 10