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Wire bonding – an interconnection method between semiconductor devices and its package

Wire bonding an interconnection method between semiconductor devices and its package

Wire bonding is a fundamental collecting step in the get-together framework for relationship between semiconductor chip and external world. A misguided wire bonding cycle will provoke metal lift disillusionment during wire pull tests, which will incite deadly open circuit in a later dealing with, for instance, reflow soldering.

A lot of wire bonding limits, for instance, fine profile, ball width, holding temperature and bond wire material properties, can impact wire bonding quality. The wire bonding system without limit upgrade could start conceivable bet for metal lifting and silicon cratering.

What is wire bonding in PCB?

What is wire bonding in PCBWire bonding is an electrical interconnection strategy using thin wire and a blend of power, strain as well as ultrasonic energy. wire bonding is serious areas of strength for a welding interaction, where the two metallic materials are brought into private contact. At the point when the surfaces are in confidential contact, electron sharing or interdiffusion of particles occurs, achieving the plan of wirebond.

In wire bonding process, holding power can provoke material contorting, isolating spoiling layer and smoothing out surface seriousness, which can be worked on by the usage of ultrasonic energy. Power can accelerate Interatomic scattering, in this way the security course of action.

what are the types of wire bonding?

There are two major kinds of wirebond: ball bond and wedge bond, the relating holding strategy, holding instrument what’s more, thermosonic gold ball holding is the most by and large used holding technique, primarily considering the way that it is speedier than ultrasonic aluminum holding. At the point when the ball bond is made on the contraption, the wire might be pushed toward any way without weight on the wire, which extraordinarily works with customized wire bonding.what are the types of wire bonding

Ball bond

Ball bonding process is to insert the bonding lead vertically into the tool of capillary knife, and the lead is melted into liquid under the action of electric spark. The ball is formed due to the effect of surface tension. Under the precise control, the falling of the knife makes the ball contact the bonding area of the wafer, pressurizes the ball, and makes the ball and the pad metal form a metallurgical combination to complete the welding process.

Then, the knife is lifted and moved along the predetermined track (arc routing). When it reaches the second bonding point (pad), the crescent type welding point is formed by using pressure and ultrasonic energy. The vertical motion of the knife cuts off the tail of the wire, thus completing two welding and one arc line cycle.

Wedge bond

Wedge bonding process is to insert a metal wire into a small hole on the back of the wedge cutter, and the bonding area between the wire and the wafer is at an angle of 30 °~60 °. When the wedge cutter descends to the bonding area of the bonding pad, the cutter presses the metal wire on the surface of the bonding area, and ultrasonic or thermoacoustic welding is used to realize the bonding welding of the first point.

Then the cutter lifts up and moves along the direction corresponding to the hole on the back of the cutter according to the predetermined track. When reaching the second bonding point (bonding pad), the pressure and ultrasonic energy are used to form the second bonding welding point, and the vertical motion of the cutter cuts off the tail of the metal wire, This completes two welds and one arc cycle.

What is bonding wire made of?

Wire bonding materials used in a ball holding process in a general sense consolidate the holding wire and holding gadget. Ball holding gadgets are called vessels, which are vital symmetric imaginative devices with vertical feed openings. The mechanical assembly’s tip is formed to give the opportunity expected in fine-pitch holding.

what’s the material of wire bonding?

Most bonding wire utilized in ball bonding is gold (Au) wire of 99,99% immaculateness, which is frequently alluded to as 4Ns wire. Amalgam wires (99,99% or less virtue) are some of the time used to meet exceptional application prerequisites, like high wire strength.

Studies have shown that certain dopant can slow Au-Al intermetallic development. 3Ns and 2Ns wires are sometimes considered to further develop gadget dependability.
what's the material of wire bonding
An exceptional thought for bonding wire is its intensity impacted zone length, which is connected with the recrystallization cycle because of the intensity from EFO. The intensity influence zone frequently debilitates the wire. A more extended heat-influence zone in the wire frequently brings about higher circle level. Some low-circle applications require high strength and a low intensity impacted zone.

Copper (Cu) wires can be reinforced for certain adjustments to the wire bonder. The changes principally comprise of utilizing a framing gas climate to forestall Cu oxidation during the free air ball development. Both Au and Cu bonding are finished at a raised temperature This interaction is called thermosonic bonding in view of the utilization of intensity and ultrasonic energy.

What is the process of wire bonding?

The essential steps in the wire bonding system consolidate achieving strong protections (first security, second security, and tail bonds),maintaining needed circles, and arranging the protections definitively. Throughput similarly is a huge variable, since it impacts the cost of the contraption.

Achieving needed first and second bonds commonly requires smoothing out holding limits. An arrangement of examination can be done to redesign these limits, which would consolidate impact force, holding force, and ultrasonic energy levels.
What is the process of wire bonding
The basic process and requirements of wire bonding include:
① Plasma clean the pad and shell.

② Lead wire and bonder adjustment. Select the appropriate lead diameter according to the pad size.

③ Lead wire bonding. Select the position of the bonding point, and pay attention to the shape of the ball and the bonding strength. Adjust the height of the bonding lead wire and the forming radian of the jumper wire.

④ Check. In addition to the microscopic examination, the defects are observed through the 40x and 1000x microscopes respectively.

what’s the advantage of wire bonding?

Associating exceptionally complex circuits at chip level with PCB sheets. Sensor arrangements frequently just feasible by wire bond application. Space saving contrasted with bundled chips. Adaptability in chip, bundle and substrate math. As an extraordinary association among chip and circuit board substrate, this strategy makes it conceivable to apply IC to substrates utilizing just at least space.

what’s the application of wire bonding?

Wire bonding may be applied to companion an IC to other hardware or to interface from one published circuit board to some other. wire bonding is with the aid of and massive concept to be the maximum shrewdness and adaptable interconnect innovation and is utilized to accumulate by way of a ways most of semiconductor bundles.

Wire bonding is applied to electrically interconnect a coordinated circuit, or a few different semiconductor machine, to a feasible steel surface. A length of little measurement, delicate metal cord is applied to make the relationship, and the bond is made by means of making use of pressure and ultrasonic vibration. Finished circuits are frequently safeguarded with epoxy exemplification.

what’s the wire bonding methods?

Wire bonding process starts by solidly connecting the posterior of a chip to a chip transporter utilizing either a natural conductive cement or a weld (Pass on Connect). The wires then are welded utilizing an exceptional bonding instrument (fine or wedge).
Depending on bonding specialist (heat and ultrasonic energy), the bonding system can be characterized to three significant cycles:
● Thermocompression bonding
● Ultrasonic bonding
● Thermosonic bonding

What is the difference between flip chip and wire bond?

In the wire bond technique (top), the kick the bucket faces up and is connected to the bundle through wires.The flip chip (base) overcomes and is regularly connected through patch knocks like the bigger ones that append BGA bundles to the printed circuit board.

Flip chip bonding can give higher I/O consider the entire region of the pass on can be utilized for associations. Because of the short interconnections ways, contrasted with wire bonds, the speed of a gadget can be gotten to the next level. What’s more, as wire bonds circles are taken out it gives a more modest structure factor.

What size is bonding wire?

What-size-is-bonding-wireThe most progressive wire bonding applications include: super fine pitch (<60-µm pitch), stacked kick the bucket, and multi-level applications. These high level applications frequently require more cycle streamlining, as well as higher necessities for bonding material and gear.

Wire bonding fine-contribute ability has been exhibited the research center at 35-µm inline pitch. For 35-µm pitch ball bonding, 15-µm wire normally is utilized with a reinforced ball breadth of 27 µm.


In spite of the fact that wire bonding is a laid out and well‐known method for micro‐joining on leadframes, direct die‐attach without lodging on printed circuit sheets has a few new necessities for the outer layer of the bond cushions and the PCB itself.

The most ideal decision of material for the bond cushions is an unadulterated gold metallisation. The nature of the surface can be tried during wire bonding utilizing the ultrasonic‐power cycle window. It will be shown that the surface and the PCB itself impact the ultrasonic and thermosonic bonding process.



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