2. LARGE WIRE ULTRASONIC
BONDING WEDGES - PAGE 2 (2)
The third style of wedge used for large wire
utilizes a cutter blade termination method. The bonding tool has either a
longitudinal U-groove or
a radius at each end. After the second bond
has been formed, a cutter blade is used to terminate the wire.
This drawing shows a typical U-groove style wedge.
This drawing shows a typical V-groove style wedge.
The bonders using these styles of wedges are
normally equipped with a cutter blade positioned in front of the wedge. Following the
completion of the second bond, the bonder head moves up and back. The cutter blade is then
activated to terminate the wire. The wire is then positioned in the groove for the next
bond. The U-groove style wedge is
popular than the V-groove style wedge. With the U-groove design, the wire deformation
occurs along the entire groove during the bonding process. The wire contacts the apex of
the groove which leads to excessive aluminum build-up at the FR and BR areas. The U-groove
design will require cleaning more often.
This bond is made by a wedge having a U-groove. The flat sections on each
side of the bond are referred to as "wings" or "ears".
Gold The V-groove style does not allow the
wire to contact the apex of the groove. This reduces the amount of aluminum
that comes in contact with the groove, thereby reducing build-up and
of the wire. The V-groove style also reduces
the constricting of the wire at the heel of the bond. This produces wires
with less heel related problems.
Figure 49. This
bond is made by a wedge with a V-groove. The outward deformation of the bond is minimized.
Note the absence of "ears" on this bond and minimal deformation of the heel
area. V-groove wedges usually require less cleaning than U-groove wedges.
courtesy of Ultrasonic Engineering Company.)