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Copper Bond Pads

Coining Al Cu Bond Pads for Power Semiconductors

Aluminum-Clad-Copper Bond Pad

The Aluminum-Clad-Copper Bond Pad is especially developed for the automotive and power semiconductor industries.  These bond pads are used for making an electrical connection between the Al-based circuitry on the semiconductor die and the Cu or Au-based circuitry on the PCB side. The method is mostly used for preventing a direct connection between Al and Au, which may result in loose connections. Over time Au and Al build an intermetallic (aka “Purple Plague) as well as creating voids (aka “Kirkendall voids”) by diffusion rate differences between the 2 elements into each other.
Copper bond pads for Power semiconductors
Currently Bond Pads are mostly used for realizing a high-current, conductive connection with Al-wire/ribbon between a power semiconductor and Cu-based PCB. The Bond Pad is typically connected at the Copper side to the PCB by soldering and at the topside to the Al-wire by ultrasonic wedge bonding. For thin gauge wire only a thin Al-clad is needed. The thicker high-conductive pure aluminum wire needs a thicker Al-clad on the pad. The ultimate dimensions for the Bond Pad are specified by the requirements of the application.

3D Solder Preform/Bond Pad

Copper-Core Connect

With the ever-increasing miniaturization of electronics and an increased number of (sub)assembly steps, not all assembly connections can be made on a 2D PCB, heat-sink or ceramic substrate, but need to be raised for making them accessible for assembly/ribbon-/wire-bonding tools or equipment and/or soldering. 

With the new Copper-Core Connect™, COINING enables designs for making a final, high-power, wire/ribbon connection to contact spots that otherwise cannot be reached or must be made in an earlier assembly step. The Copper-Core Connect™ can be soldered to the ground level board and can be provided with the same or a different solder top-side for placing a component at the required height or making an elevated connection.

Copper-Core Connect are available in Solder/Cu/Solder and Solder/Cu/Al(Au) configurations for soldering and respectively Wire-/Ribbon bonding. While the Solder/Cu/Solder 3D preform height can be as low as 0.0026” depending on the choice of solder alloy, the minimal Wire-/Ribbon bonding Copper-Core Connect™ height for the Solder/Cu/Al configuration is 0.010” typical.