is there any issues with gold wire bonding on die aluminum bond pads

a long time ago i've heard about some issues with wire bonding with gold wire on aluminum pads.

tried to findout something about that but i don't find anything.

any ideas if there are any issues with that [gold wire bonding on al pad] or not?

R1kky said:

a long time ago i've heard about some issues with wire bonding with gold wire on aluminum pads.

tried to findout something about that but i don't find anything.

any ideas if there are any issues with that [gold wire bonding on al pad] or not?

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Electromigration can be an issue if current densities are high enough, due to lattice diffusion at intermetallic junction.

There can be, but this has been the norm for commercial
IC products for decades.

The Al:Au interface is prone to form intermetallic compounds
(chemistry varies w/ time@temp) and one of them is the
"purple plague" (Kirkendahl voiding ensues, the color is the
warning sign). Because the intermetallic species occupies
less space than the parent constituents, voids develop in
the bond wire : pad interface.

The HiRel niche uses aluminum wires, aluminum pads and
you only see this interface at the bond posts where the
material is thicker (bond pad aluminum may be less than
a micron thick, outside some RD and power IC flows)
and of course the packaged parts are individually bond
pull tested and optically inspected with detailed specs
on assembly processes.

If your assembly process is normal and your application
temp range is commercial, fuggedaboudit. Step out of
the air conditioning and put on your uniform, and maybe
you want to take more care.