Heavy Copper Bonding Wires

The outstanding properties of large-diameter copper bonding wires from Heraeus let you solve many technical challenges in electronics applications while at the same time reducing costs.

Heavy Copper Bonding Wires

Copper as an interconnect material provides excellent electrical conductivity and fusing current values. That enables the use of thinner wires compared to aluminum wire connecting, resulting in better heat dissipation. In addition, copper is a mechanically stable metal, resulting in stronger wire connections and high loop stability.

Heraeus offers three main types of heavy copper bonding wire: PowerCu, PowerCu Soft, and CucorAl (aluminum-cladded copper wire). All of them exhibit outstanding long-term reliability and result in highly robust bonds able to resist high temperatures and mechanical stresses. They are ideal for helping you solve the challenges posed by thermal management, the need for high robustness, miniaturization and weight reduction, as well as increased reliability. This includes power management in high-voltage modules and systems, even at high energy densities and temperatures.

We are unique in focusing on thick bonding wires as part of our core business, while in parallel offering solder and sinter pastes, substrate materials, and other power electronics products. We supply these products in forms that simplify and streamline your own processes by enabling lean, cost-effective production with standardized methods.

Heavy copper bonding wires from Heraeus may be just the solution you’re looking for.

Your benefits at a glance:

  • Optimal bondability due to extreme softness and minimal resistance to deformation
  • Uniformly fine grain structure
  • Extremely high thermal stability
  • Minimal electrical resistivity
  • A very wide bonding process window
  • High productivity: special Heraeus spools enable extra-long lengths
  • High reliability in longlife and reliability tests, especially when combined with other advanced technologies for die top connecting and die attach
  • Compliance with legal requirements including REACH and RoHS


  • Engine management (engine control units)
  • Transmission controllers
  • Power electronics modules for drivetrains in electric and hybrid vehicles
  • Generator control
  • SiC (silicon carbide) technology for reducing electric power losses
  • Gallium nitride (GaN)-based electronics

Power electronics in industrial use:

  • State-of-the-art IGBT modules for drives, current inverters, and power supplies
  • Inverters for wind and water power, solar energy, and other renewable energy sources
  • Trains and other types of transportation

PowerCu Soft:

PowerCu Soft bonding wire is our most popular material for advanced semiconductor packaging. It performs excellently in next-generation applications that need to be highly robust and withstand temperatures up to 200 °C. In lifetime tests, Heraeus PowerCu Soft bonding wire used for wedge applications lasts 10 to 30 times as long as conventional aluminum technology. Its fusing current values are also superior to those of aluminum wire.

PowerCu Soft factsheet

CucorAl (aluminum-cladded copper wire):

CucorAl bonding wire is a composite consisting of a copper core with surrounding aluminum cladding. This mix of materials possesses better electrical and mechanical properties than pure aluminum, as has been confirmed by long-term passive temperature cycle tests and, especially, active power cycle tests. This heavy wire contains between 60 % and 70 % copper by volume. The available diameters range from 200 μm until 500 μm. The Al/Cu structure provides reliable bonding windows without altering chip metallization.

CucorAl factsheet

Comparison of Cu- and Al-bonding wires:

Properties Units Copper Aluminum
Melting Point °C 1083 658
Density g/cm3 8.9 2.7
Specific Heat (@ 20 °C) J/g K 0.386 0.900
Thermal Conductance kW/m2 K 39.4 22.2
Coefficient of Linear Thermal Expansion ppm/k 16.5 23.1
Electrical Resistivity (@ 20 °C) 10-8 Ω m 1.7 2.7
Electrical Conductivity (@ 20 °C) 107 / Ω m 5.88 3.65
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