Wire bonding machine/ wire bonder is a semiconductor packaging device used to communicate and connect chips and substrates through metal wires.

1. According to the principles of bonding, there are three types of bonding: hot press bonding, ultrasonic bonding, and thermal ultrasonic bonding:

(1) Hot pressing bonding refers to the deformation of the wire (>250 º C) heated at high temperature under the pressure of the hot pressing head, and the bonding is achieved by controlling time, temperature, and pressure;

(2) Ultrasonic bonding is the elastic vibration of applying pressure and ultrasonic frequency to the welded surface at room temperature, which destroys the oxide layer between the welded parts and solidly bonds two solid metals;

(3) Thermo ultrasonic bonding is a combination of hot press bonding and ultrasonic bonding, which can reduce heating temperature, improve bonding strength, and is beneficial for the reliability of devices

2.  From the perspective of bonding process, it can be divided into two types: ball welding bonding and wedge welding bonding:

(1) The first solder joint of ball welding is formed by melting the bonding wire through high-voltage arc discharge, forming a spherical shape under the action of surface tension. Then, the ball is pressed onto the electrode of the chip, and the bent gold wire is extracted from the first solder joint and pressed to the corresponding position, forming two solder joints;

(2) Wedge welding is the process of pressing down two wedge-shaped welding points to form a connection, without the need for ball burning technology. Figure 1 and Figure 2 are schematic diagrams of solder joints for two bonding processes. The commonly used bonding wires for ball welding are gold wire, silver wire, and copper wire, while the commonly used bonding wires for wedge welding are gold wire, aluminum wire, gold strip, or aluminum strip.