WP3_Bham; 10July 2014; John Wilson 1

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 Wilson 2

Stencil

• Symmetric 5 dot pattern: 2mm diameter, centres separated by 1.91mm.• Rectangular ASIC: 7.9mm x 6.7mm

7.9

6.7

1.91 1.91

1.91

1.91Area of dots = 30% ASIC surface

a

b

c

a = 1.05;b = 0.44;c = 0.70

WP3_Bham; 10July 2014; John Wilson 3

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 Wilson 4

Profiles of cured glue dots (old clamping)

Expected stencil dot

Far too much glue

Very non-uniform

WP3_Bham; 10July 2014; John Wilson 5

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 Wilson 6

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 ASICsSometimes glue has hardly marked the hybrid – but the shear strength exceeds 5kg!

After shear testing

WP3_Bham; 10July 2014; John Wilson 7

WP3_Bham; 10July 2014; John Wilson 8

WP3_Bham; 10July 2014; John Wilson 9

WP3_Bham; 10July 2014; John Wilson 1010

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.

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