Oxygen-free copper is widely recognized as one of the highest-grade copper material, delivering exceptional electrical and thermal conductivity through its extremely high purity and ultra-low oxygen content.
For more than 60 years, Mitsubishi Materials has been at the forefront of oxygen-free copper production. Through decades of technological innovation, metallurgical expertise, and uncompromising quality standards, we have established a reputation as a trusted supplier of high-performance copper materials to industries around the world.
Today, with a stable production capacity of approximately 10,000 tons per month, Mitsubishi Materials Oxygen-Free Copper supports innovation across the electrical, electronics, automotive, and semiconductor sectors, where reliability and performance are critical.

The global transition toward electrified mobility, renewable energy, and advanced semiconductor technologies is creating unprecedented demand for conductive materials capable of handling higher currents, greater thermal loads, and increasingly challenging operating environments.
Oxygen-free copper offers the highest levels of electrical and thermal conductivity among commercial copper materials, making it indispensable for these applications.
To meet these evolving requirements, Mitsubishi Materials launched MOFC (Mitsubishi Materials Oxygen-Free Copper) in 2021.
Built upon more than six decades of manufacturing excellence, MOFC represents a portfolio of premium oxygen-free copper solutions engineered to deliver exceptional performance, reliability, and consistency for next-generation technologies.

As electrical systems become more powerful and compact, conductive materials are increasingly required to combine superior conductivity with enhanced mechanical and thermal performance.
Historically, achieving high strength, spring properties, and heat resistance has required compromises in electrical conductivity.
Developed through years of advanced materials research and introduced in 2021, MOFC-HR overcomes this challenge. It combines the outstanding conductivity inherent to oxygen-free copper with exceptional strength, spring properties, and heat resistance.
MOFC-HR provides designers with new possibilities for high-current, high-reliability applications in automotive, power electronics, and advanced electrical systems.

The reliability of power semiconductor modules depends heavily on the integrity of their substrate materials, particularly under elevated-temperature operating conditions.
Oxygen-free copper is widely used as the circuit layer material in Active Metal Brazing (AMB) substrates. During manufacturing, however, exposure to high temperatures can lead to grain coarsening, potentially affecting performance and reliability.
Introduced in 2025 following years of development, MOFC-GC is specifically engineered to suppress grain growth while maintaining the exceptional electrical and thermal conductivity of oxygen-free copper.
By preserving a fine and uniform microstructure throughout high-temperature processing, MOFC-GC contributes to improved substrate reliability and stable long-term performance of semiconductor devices.