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As
the flip chip’s
I/Os
(Inputs/Outputs) become thighter in pitch and their number is rapidly
increasing, it becomes critical to ensure that
the substrate’s flip chip pads are capable of supporting ICs with more bumps at finer pitches. The
AMITEC solution for fine pitch,
high I/O flip chip devices, is it’s patented MOP bumping
technology. A MOP (Metal on Pad) bump is basically a metal pillar
structure formed on the external pad layer of the substrate and coated
with Ni/Au. When the flip chip bump (C4, Solder or Lead Free), melts
during the reflow chip attach process, it wets the MOP
top surface as well
as its side walls. This creates an extremely reliable and robust
“3 point” electrical contact structure between
the bump and its corresponding MOP. Since MOP structures are characterized
by very high aspect ratios and are very planar when compared one to the
other, they
are capable of meeting the most demanding requirements
of the next generation flip chip
devices. AMITEC substrates with
MOP bumps at 80µm pitch successfully passed 3000 thermal cycles -55°C to
125°C. |
