Ball Bonder (25 um Gold wire, K&S 4524A)
Wire bonding is a method of connecting metallic wires to electronic devices. Within electronic devices, wires carry the electrical signals and electrical currents that make the devices work. Common metals are used for wire bonding, such as gold, aluminum and copper. Each of these metals can be forced to bond together using a wire bonding machine. Bonding results are best using the same metals for the wire and bond area. Different metals can be wire bonded. Gold and aluminum bonded together is very common. Copper is usually bonded to copper and not to gold or aluminum. When two different metals are connected with wire bonding, the intermetallic region develops a type of alloy that forms when the bond is made. Wire bonds of the type formed by two different metals will provide the shortest useful life. Wire bonds of a single metal (wire and bond area made of the same metal) will provide the longest useful life.
Ball bonding requires the attachment of a ball formed on the end of a wire. There must also be a second attachment made to complete the electrical circuit. The second attachment is called a wedge bond. Because of this, ball bonding is sometimes called “Ball-Wedge Bonding”. The ball bond is commonly called the “1st bond, while the wedge bond is referred to as the “2nd Bond “ .
This ball bonder is a manual bonding instrument. 25 micron (0.001”) diameter gold wire is used in this ball bonder. The system uses NEFO (Negative discharge Electronic Flame Off system) for ball formation. NEFO is the most common way and provides the most consistent ball size control. 25 micron diameter wire may be used to form a ball size of approximately 40 to 100 microns diameter.