Copper (Cu) Wire Bonding Technical Benefits Overview

October 31, 2012, anysilicon

We love copper (Cu) wire. In fact, we already described in our post “Copper Wire (Cu) Reduces Package Cost” the cost advantages of copper wire bonding compared to Gold (Au) wire. Copper wire introduced some challenges to assembly houses (such as ASE, Amkor, STATS ChipPAC) but also offers a few technical benefits, in addition to cost.


ASICs utilizing copper wire bonding can offer the same quality level, reliability and performance as those using gold. Copper wire delivers the same electrical characteristics as gold wire, but it offers lower resistance (R) which can be beneficial for certain applications which are sensitive to IR drop for example.


Despite the benefits and substantial industry know-how on Copper wire, gold wire is still benefiting from a long track record of success (many decades) and deployment of billions of ASIC devices. Therefore, Gold (Au) wire is still enjoying a huge circle of trust by being a reliable material.



Resistance (R)  – Copper (Cu) wire vs Gold (Au) wire


Wire bonding length defines the resistance, capacitance, and inductance of the wire. Long wire bonds can be critical to the overall package performance.


In applications where resistance can improve performance, using Copper (Cu) wire can offer real technical benefits. Furthermore, Cu wire reduces heat dissipation within a package.


Copper wire offers better resistance than gold wire.



Capacitance (C)  – Copper (Cu) wire vs Gold (Au) wire


There are no drawbacks on Cu wire capacitance:

Copper wire self capacitance is nearly the same for Gold (Au).



Inductance (L)  – Copper (Cu) wire vs Gold (Au) wire


There are no drawbacks on Copper wire inductance:


Self inductance is nearly the same for Gold (Au) and Copper (Cu) wire.


Copper wire bonding is widely adopted in the industry and gaining acceptance in all market segments including the automotive industry. In the leading assembly houses copper wire has become the preferred material for wire bonding interconnects.


Copper wire bonding offers better performance and lower cost. With these benefits there is no doubt that within 5-10 years gold wirebonds will be a rare material in the assembly house.