Gold and Aluminium chip bondpads

[#NGUYEN QUANG VINH#]

Hi everyone,
As I know, Gold and Aluminium are the most commonly used materials in chip bondpads.

In the past, some manufacturers have switched from Aluminium to Gold, the main reasons were the excellent corrosion resistance and strong bonding with Gold coated wires. But now it seems that corrosion problems can be overcome by encapsulation process ( the bonding site is encapsulated with polymer resin ), and Al-Au can give quite adequate strength.

Could anyone tell me other advantages of using Gold instead of Aluminium for chip bondpads?

My company is planning to use Aluminium for our products, since it will reduce our manufacturing cost and enviromental problems.

Have a nice day,
Vinnie.

 

[Ken Finney]

Hi everyone,
As I know, Gold and Aluminium are the most commonly used materials in chip bondpads.

In the past, some manufacturers have switched from Aluminium to Gold, the

main reasons were the excellent corrosion resistance and strong bonding with
Gold coated wires. But now it seems that corrosion problems can be overcome
by encapsulation process ( the bonding site is encapsulated with polymer
resin ), and Al-Au can give quite adequate strength.

Could anyone tell me other advantages of using Gold instead of Aluminium for chip bondpads?

My company is planning to use Aluminium for our products, since it will

reduce our manufacturing cost and enviromental problems.

Have a nice day,
Vinnie.

The best way to model encapsulation is as a sponge that holds contaminants
in contact with the die, wirebonds, and wire. The best encapsulants being
used today are a lot better that what was used 20 years ago, but recently
some manufacturers have gone back to inferior materials to save cost, plus
their customers don't want/need the better ones. That being said, if your
product has a five year life or less, and isn't intended for a harsh
environment, you probably don't have to worry about anything. Manufacturers
are heading towards gold and copper because of their greater ductility which
is needed as bondpads get smaller and smaller.


http://nepp.nasa.gov/wirebond/horsting analysis.htm


http://www.eccb.org/pbps/tg/wirebond.htm