Divisional Silicon Facility - Bond Lab
Various Methods for Die Attach
We use the following conductive epoxy glues:
- Conductive epoxy glue epotecny E205, curing 4 hours at 60°C (data sheet available in the bond lab)
- TRA-CON BIPAX type BA2902, curing 24h at room temperature (glue owned by NA60)
- Vacuum and high temperature applications (e.g. HPD) Epotek H31
- There is a range of epoxy glues available in the CERN stores (see stores catalog, material group 37.)
We have good experience with thermoplastic films from Cookson. Thermoplasts are polymer materials consisting of linear chains without cross-links. Therefore they can be heated above the so-called glass transition point where they become flowable again and rework can be done. They harden again when cooled down.
Staystik films exist with or without filler materials. One can therefore choose between a range of materials from high thermal and electric conductivity to thermally and electrically insulating.
The standard material which we use in the bondlab is electrically and thermally conductive Staystik film type 571 (see data sheet).
There is an important constraint: the interface to be bonded needs to be heated to about 150°C under gentle pressure for about 10 secs. We use our Die Bonding set-up for this purpose.
We have verified the radiation hardness of Staystik thermoplastic film 571 in the CERN PS irradiation facility.
We are currently experimenting with anisotropic glues as an alternative to wire bonding in certain applications. Prel. report.
Status: 12/10/04
(I. Mcgill, C. Joram, M. Moll)