Application of Microwave PLASMA in Wire Bonding

Lead wire bonding is the most widely used bonding technology in semiconductor packaging. The purpose is to connect the input and output terminals of the chip with the lead frame.
In the process of wire bonding, do you suffer from "bonding separation"?

What exactly causes bond separation?

Bonding separation of semiconductor devices is one of the most common failure modes. This failure mode is difficult to eliminate by conventional screening and testing, and can only be exposed under strong vibration, so it is extremely harmful to the reliability of semiconductor devices.
Factors that may affect the bonding reliability of the inner lead are:
01.Increased contact resistance in bonding area

The photoresist or passive film in the bonding area is not removed completely, which leads to the increase of contact resistance and the reduction of bonding reliability.

02.Lead frame oxidation

The lead frame is generally made of copper, which is prone to chemical reaction with water molecules and oxygen elements in the air, thus producing an oxide film.

03.Pollution in the process

Dust contamination caused by external environment and human metabolism may cause organic contamination and sodium contamination.

Before the wire bonding, plasma cleaning can effectively remove the photoresist in the bonding area, the oxide film of the lead frame, and the organic pollutants in the process, so as to improve the bonding strength and reduce the bonding separation.

Microwave PLASMA Solution

01 Microwave PLASMA Removal of Residual Photoresist

The process gas is ionized by the high-frequency alternating electromagnetic field generated by the microwave source oscillation, which reacts with the photoresist to achieve a good degumming effect, thereby reducing the contact resistance and increasing the bonding reliability.

02 Microwave PLASMA treatment of lead frame oxidation

03 Removal of organic pollutants by microwave PLASMA

Microwave PLASMA can remove the dust contamination caused by the external environment, organic contamination and sodium contamination caused by the new generation of human body, and the residual gold plating solution of chip shell and other incoming materials.

The organics attached to the surface of the bonding zone react with oxygen to produce carbon dioxide and water vapor for emission.

The organics attached to the surface of the bonding zone react with hydrogen to generate methane and ethane gas for emission.

Sindin Microwave PLASMA Treatment Effect

Conclusion: Microwave Plasma treatment of lead frame can not only reduce the water drop angle, but also restore the original luster of metal.

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