WHAT IS BONDING WIRE?

The bonding wire is one of the major materials being used to connect between chips and substrate, including chip with chips, during the IC assembly process. It's an important item to ensure the electrical connection between chips and the outer interface and make sure the work-ability of IC input/ output function being stable. The wire bonding method is one of the dominant processes in the field of packaging assembly and the application ratios reach 90% due to it being the simplest way with the lowest cost, comparing to the other ones. Even with the new state of IC packaging technology nowadays, the wire bonding system will be the mainstream method in the near future.

There are 3 kinds of wire bonding method currently:

1) Thermal pressing bonding: The bonding wire, being heated over 250 degrees, is deformed by the pressure from the thermal capillary during bonding process. The interface of different metals being near atomic condition, so it can form the solid bonding through the diffusion of metallic atoms each other.

2) Ultrasonic bonding: Through the vibration of high frequency sonic, the pressure of capillary, with the bonding wire, on the top of IC' s contact area can remove the oxidation on the surface and produce the enough heat, so it can be bonding solidarity. During the bonding, without extra heat and electricity or flux, it'll not impact the physical or chemical characteristics of parts.

3) Thermal sonic bonding: The bonding method combines thermal pressing and Ultrasonic bonding together. During the Ultrasonic operation, the heating blocks of wire bonding fixtures and the capillary being heated to 150 degrees, it can increase the atomic diffusion between wire and IC chip's metal and enhance the reaction each other. Because the lower heating temperature with higher bonding strength, it becomes the mainstream of bonding method so far.

Bonding Wire Manufacturing Process：