Invention of transistor
Development of wire bonding technology

Transistor is a semiconductor component that can amplify an electric signal or turn the signal on and off. The commercialization of transistor in the late 1940s has accelerated the growth of semiconductor industry ever since.
Bonding wire is used to transmit an electric signal from a semiconductor element to an external part. The wire bonding technology was developed by researchers at Bell Laboratories in the US in the late 1950s. From its inception, gold was used as a material for bonding wire.

NIPPON STEEL initiates basic research
on new copper wire

Although gold wire had been used for over 50 years due to its high performance, it was a very expensive material. As the electronic devices became more and more functional, the semiconductor packages also became more complex which in turn led to an increased use of gold wire. Coupled with the souring gold price in the 2000s, a call for a replacement from gold has begun to be taken seriously. Around 2004, NIPPON STEEL Group began basic research on the development of copper-based bonding wire. It was an area of specialty that no innovation was made for a long time. Their research suffered numerous setbacks.

Successful development of
palladium coated copper wire “EX wire”

NIPPON STEEL Group succeeded in the development of EX1 wire which has a palladium coating on top of a copper core material. With the palladium layer controlled in nano level on the surface of copper wire which has a diameter of only around one-fifth of human hair (15-30μm), EX1 realized a high bonding performance and corrosion resistance that are not possible by conventional copper wire.

Development of
mass production technology
Start of sample shipment

In 2007, Nippon Micrometal began the development of mass production technology for EX1. We envisioned a global expansion from the beginning and aimed for a de facto standard for EX wire.

Sale of EX1 begins
Becoming the world’s de facto standard

Once realizing the quality control in nano-scale, EX1 was released for global sale. The thickness of palladium coating is less than a few hundredths of the wire diameter, and the thickness has to be uniform throughout the production. Its development phase accompanied a valley of death. Overcoming all the difficulties by the passion and fortitude of engineers and researchers involved, EX wire pioneered a new market “palladium coated copper wire market” and became a de facto standard of the market across the world.

Valley of death: A challenging phase for a product development in which the probability of failure outweighs the potential outlook.

Market expansion of EX wire

Successive series of EX1 have been developed and released one after another corresponding to market needs. EX series are still evolving.