Figure 5. The
protruding-V TAB tool is one of the most popular TAB tool styles. Similar to the
protruding radius tools, the protruding-V design is most often called out with the SDFA
option giving the lead the bonded appearance of an "X".
This photo is a gang bonded TAB device. The benefit of the single point TAB
approach is that each lead is bonded separately. This assures the quality of
each lead. The downside is that single point bonding takes considerably
longer than gang bonding.
courtesy of Integrated Reliability Services, Inc.)
Figure 7. One
of the biggest difficulties in TAB is the alignment of the device lead or finger over the
package lead. Some of the tightest pitches for any interconnect technology is TAB devices.
courtesy KMD-Kyushu Matsushita Electric Co., LTD, bonds made by SB-series
Several wafer bumping methods have been
developed. The most common of these methods utilize the same techniques used
in making standard die metallization. Other methods of wafer
bumping involve the process of putting a ball
bond down on the die pad, terminating the wire just above the ball and then
flattening the ball to become the new raised die "pad".
One of the techniques for wafer bumping involves the bonding of ball bumps
on the die. Gaiser has developed several tool series for ball bumping. Since
the wire is terminated above the ball, there is no need for an outside
radius or a face on the capillary to make the lead bond.
Figure 9Pictured here is
a device that has had ball bumps placed and tamped in preparation for the
courtesy Hughes Aircraft
Figure 10. The
tamping tool is used for tamping wafer balls or to flatten out rough metallization
in prebonding. This ball bump has been tamped.