Soldering a head slider to a tongue surface can be achieved by using gold
ball bonding (GBB) or solder
ball bonding (SBB).
In recent years, K/S has expanded its product offerings through strategic acquisitions and organic development, adding advanced packaging, advanced SMT, wedge bonding and a broader range of expendable tools to its core
ball bonding products.
Abstract: Copper
ball bonding faces more challenges than gold
ball bonding, for example, excessive deformation of the bond pad and damage of Cu/ low-k structures, because of the much greater hardness of copper free air balls.
Rodrigues, "Simulation of
Ball Bonding on Various Bond Pad Structures", Proceedings of IEEE 14th Electronics Packaging Technology Conference, EPTC 2013, Singapore, Dec.
There were work done [6 & 7] on gold
ball bonding adhesion is influenced by both ultrasonic force and time of the process, the studies were done on aluminium bond pad, surface roughness effect were not discussed except on the native oxide formation on the bonding surface.
Chen, "A re-examination of the mechanism of thermosonic copper
ball bonding on aluminium metallization pads," Scripta Materialia, vol.
Wedge bonding can achieve finer pad pitch geometries than
ball bonding with the same wire diameter because of the smaller amount of bond "squash" or wire deformation.
The consumer market demand for smaller and more complex electronic devices is driving the wire bonding industry to set new
ball bonding limits.
Processes include high accuracy component assembly with eutectic solder or epoxy, precision
ball bonding, and wedge bonding for fine pitch devices, as well as epoxy, laser weld and solder based attachment of actively aligned photonic devices.
Figure 6 shows a relationship for impact force and static bond force with bond pad cratering for thermosonic
ball bonding. [3] Low bond pad impact force is generally used when round wire wedge bonding delicate ICs such as GaAs, but this process decreases bonding speeds dramatically.
Gold is the most widely used metal for IC wire bonding because of its resistance to surface corrosion and high productivity through the gold
ball bonding process.
Gold is used because it is normally inert, well suited to the
ball bonding process and demonstrates excellent loop formation and cycle performance.
