Basics of Wire Bonding
Miniaturization is the norm today. Electronic components and microelectronics have become smaller and smaller in scale. With this technology, the use and demand for wire bonding has rapidly increased. The wire bonding method is utilized in all types of semiconductors and integrated circuits. The process sets wires for the needed components through specific combination of pressure, energy, and heat.
Wire bonding is highly regarded as the most popular and dominant interconnect technology due to its reputation for reliability, performance and versatility.
The wire bonding process eradicates the need for high levels of heat that is usually present when using other ways of attachment like soldering. Soft types of fine diameter wires known as bond wires are used in this approach.
Bond Wires
Gold, copper or aluminum are materials used for bond wires. Selected alloys are also resorted to for specific requirements and properties. These fine wires can be as small as 15 microns and can be as large as 500 microns depending on the applications.
The material used are carefully selected based on the requirements, design and applicant of the components. Bond wires impacts on the production of the component as well as the cost of manufacturing.
Types of Bonding
There is a combination of pressure, heat and ultrasonic energy that is used in the wire bonding process. Thus, careful consideration on what metals best suited to the bonding process should be made.
These are the types of bonding available:
- Thermosonic bonding – This type uses ultrasonic energy, heat and pressure applied to the wire and the substrate while bonding them together
- Ultasonic bonding – This uses pressure and ultrasonics without the use of heat. Both wire and material are in room temperature during the entire process. Ultrasonic bonding can use any type of bondwire.
- Thermocompression bonding – This uses heat and pressure without ultrasonics during the bonding cycle. The contact surface of the material is heated and in some instances the bond wire as well. The two materials are pressed together to bond. Only gold wires and gold material can undergo this method.
Every bonding has its specific bonding technique which is based on the substrates, the bond wire and the application.