FDR and others: see the latest development in Hybrid developtment at KEK page
ATLAS SCT Barrel module wire-bonding scheme, T. Kohriki et al.,
00/10/13
ASIC gluing - Mask method, T. Kohriki,
01/08/02
Dimensions of the Cu/Polyimide barrel hybrid version 4, 00/08/21
Masking bonding pads is recommended while attaching ASICs in order to minimize contaminating bonding surface
Electrically conductive epoxy -- Eotite p-102 has been used successfully in fabricating modules at KEK.
This glue will be tested in the module-0 hybrid/module programme.
There are two other products also known and available.
Recommended curing temperature and time for this application:
Temperature being recommended less than 80 deg.C which is the glass transition temp.
of the epoxy glue in laminating the flex circuit and the bridges
Wire: 1% Silicon Alminium, Stress relieved, 25 miron diameter being used in common
Loop height: approximately 20~25% of bond-to-bond distance being recommended
Sample wire bond pulls: 3 bonds (1.5 mm bond-to-bond distance and 0.38 mm loop height)
at a scratch pad (2 mm x 2 mm square) in each side, pull test to be performed and
Xbar-R to be recorded prior to the ASIC wire bonding (Do not forget to discard the debris
of the sample bonds 100%. Any floating debris into the sensor bonding area may lead to
high voltage shorts)
Japan -- is using tempolary folding fixtures.
The hybrid mounting steps are:
(1) set a hybrid to the hybrid holding fixture,
(2) apply the epoxy (Araldite2011+BN) to the steps of the side of hybrid,
(3) set the sensor-baseboard assembly to the sensor-baseboard holding fixture,
(4) mate the hybrid holding and the sensor-baseboard holding fixtures,
(5) set the assembly on the xy stage of a measuring microscope,
(6) define the module centre from sensor's fiducial marks,
(7) align the hybrid to the sensor-baseboard assembly with the fiducial marks
on the hybrid while pressing the hybrid holding and the sensor-baseboard
holding fixtures,
(8) cure at 25 deg.C overnight,
(9) flip the assembly,
(10) repeat the steps (2), (6)-(8) for the other side of hybrid.
The cirtical point of the steps is holding the facings on a flat surface
when the hybrid is pressed and cured.
If not, the facings may deform relative to the rest of the baseboard, especially at the neck.
A future plan is to develop a precision sensor-baseboard holding and
a precision hybrid holding and folding fixture, which mate accurately.
Nordic -- has made a folding jig for the hybrid-to-module step. The jig is based on the G. Taylor's folding jig modified to the barrel geometry. The modules made up to now has bean made of module components in different states of development and a single jig cannot meet all available components. We have therefore not used the folding jig on our previous modules because it was designed for the most recent module version.
UK -- is protopying a hybrid mounting system which allowed non-dedicated staff to fit any hybrid onto a 4-detector sub assembly. If possible it had to contain items that might transfer to other operations such as wire bonding. Its major action is to allow alignment of the hybrid in XY and Z relative to the previously aligned detectors. The main point to understand in the mounting of a hybrid is that the action is to wrap the 4-detector sub assembly around the hybrid, rather than the inverse.
US -- (to be added)