Via hole filler for via-in-pad applications
Jun 22, 2005
The via-in-pad technology is becoming a more essential and efficient strategy used to support finer pitch devices. Via holes in the centre of SMD pads must be reliably closed in order to avoid solder seeping through to the component side and flux residues settling in the holes as well as to ensure the sealing for vacuum adaptation during the incircuit-test.
The use of the 2-pack via hole filler SD 2768 NB offers the decisive advantage that absolutely no bleeding occurs in contact with gold or other metallic surfaces (Index NB = no bleeding); thus SD 2768 NB is particularly suitable for via-in-pad applications.
When optimally processed the high solids content of the via hole filler SD 2768 NB ensures a safe filling of via holes without any solvent inclusions as well as a very low volume shrinkage so that via holes remain completely closed even after curing.
The 2-pack via hole filler SD 2768 NB exhibits optimum printing properties for an application by means of screen printing. After curing an almost insoluble filling results that is distinguished by an excellent chemical resistance.
Being a trend-setting new development it is a matter of course that the via hole filler SD 2768 NB complies with the following requirements:
-- corresponds to the best flame class V-0 acc. UL 94
-- excellent solder bath resistance, even in lead-free soldering processes
-- contains no substances whose use is restricted or prohibited by the RoHS directive 2002/95/EC, the ELV directive 2000/53/EC or the WEEE directive 2002/96/EC.