Copper Wire (Cu) Bonding Reduces Package Cost

October 31, 2012, anysilicon

Do you know someone that is not eager to reduce their ASIC production costs? I don’t.  Some say that redesign changes can lead to significant cost reduction, for instance – using a more advanced silicon technology node to shrink the die size. True, but this is a really big, painful step with many implications. How about a much simpler method that will let you cut 5% to 15% of your assembly cost? Copper (Cu) Wire Bonding!

A relatively new technology in the package domain, called copper (Cu) wirebonds, involves a simple and straightforward modification to exiting gold-based packages. Whether you use a QFN or BGA wirebond based solution, a simple change could save you lots of money in the long run and allow price optimization from day one.

Until now, the majority of wirebond packages were based on gold (Au) wires, and to be honest, everybody was very pleased. However, the increases in gold prices have resulted in many ASIC suppliers confronting a yearly price increase in their assembly costs.



In fact, assembly houses have already started specifying the gold price level as part of price quotations of Au wirebond-based package. This allows them to correct the package price when the gold price goes up.

While Cu wire introduces a few technical benefits, the main driver of copper wire in the industry is cost.

Overall the copper wire technology is 3 years in full production and over 15B devices have been shipped.  Most of the top 4 packaging houses are already supporting cu wirebond technology and will be able to help you save 5%-15% of your package cost.

  • Jeroen Van Ham – ICsense

    Interesting thoughts ! However 2 remarks:
    1/ Last 3 years, the gold price went down to a level of 1207 USD/oz today, so somewhat misleading to cut the graph at 2012…
    2/ Cu bonding is not acceptable in hi-rel markets like automotive. This is at least what I still perceive in today’s discussions.

  • SemiMike

    Yes, copper wire bonding is very slightly less reliable for some applications based on existing history. But its been studied in volume since 2010 at least and confidence improves over time. Gold wire bonding was TERRIBLE compared to ALUMINUM when packages were solder-sealed, generating “purple plague” intermetallic compounds. But as non-hermetic packaging advanced, no high temperatures were seen AFTER the wire bonding step so gold regained popularly. Copper also has “intermetallics” that can form on aluminum pads. And worse, copper forms brittle thin spots in some bonding schemes. Luckily failures during molding are captured in final test unless they are intermittent.
    So early rel studies relegated copper wire bonding to the “commercial” rather than “hi-rel” product families. Over time, “20 year life predictions” can be made given enough failure data on each package type meanwhile phone-life seems to depend on batteries but cars are lasting decades. Current automotive field failure rates are being driven down in contracts to 300 parts per billion by Bosch and others with “zero defects” goals. Copper may have to wait a bit.