Diebonder
Delvotec Pegasus 3600
Die bonding
The die bonder is used to dispense adhesive in a pre-chosen pattern
before the die is placed on the substrate. The adhesive is then cured in
an oven.
Flip chip
The die bonder also has flip chip capabilities. Flip chip provides high
packaging density and performance and a low packaging profile. Flip chip
technology is defined as mounting the chip, with the active side facing
down, on a substrate with any kind of interconnect material. In most, if
not all, flip chip systems in production today the chip is bumped, i.e.,
on each contact pad on the chip there is a quasi-spherical bump. The bump
array pattern is mirrored onto the substrate chip site. The bumps are
usually metal and serve as the joint forming material, either together
with solder or adhesive or through melting the bump itself.
The advantages of flip chip technology are the short interconnects for
improved electrical performance and reduction of size and weight which
results in cost savings since less silicon and circuit board material are
used. The total size can be reduced in three dimensions because the naked
chip takes less space both in height and in width compared to the
packaged chip. Each chip can have many connections since it is possible
to have contact points on the whole surface area instead of just at the
periphery.
In optoelectronics the requirements on alignment accuracy are often very
extreme. Flip chip offers the benefit of self-alignment through the
soldering process.
Ballbonder: Delvotec bonder 5610
Wire bonding
A gold or aluminium wire is bonded between each pad on the chip and the
corresponding bonding surface on the carrier. After chip mounting and
bonding the chip and its wires are protected from mechanical and chemical
impact by a local epoxy encapsulation called glob top or dam and fill.
For additional protection the entire module can be encapsulated, a method
used when the electronics will be exposed to harsh environments. Today,
about 95% of all chips are wire bonded, either inside a package or
directly to a substrate.
Stud bumping
The equipment has the option of making stud bumps for flip chip assembly.
Bumping flip chips can be achieved in many different ways. Today the
availability of bumped dies is considered to be a significant bottleneck
for flip chip production. One method of bumping is to use a ball bonder
to make stud bumps. A ball bonder is used to form a ball on the aluminium
pad. The wire is then pulled to breakage. The high speed of today’s wire
bonders makes ball bonding an attractive alternative to plating. This
method is especially suitable for prototyping.
Deep access wedge-wedge bonder
Delvotec bonder 5632
The deep access bonding head makes it possible to reach down in very
narrow cavities. The machine uses both gold and aluminium wires.
Pulltester 5600
A pulltester is used to verify the bonding parameters.