Wire bonding problems can come from many sources. First, you must the be
certain of the type materials you are bonding. Au/Ge/Ni ohmic contacts very
hard compared to gold. Make sure you have at least 200nm of pure gold deposited
over these contacts.
Second, gold bonding wire doped with silicon has a definite shelf life. It
becomes brittle with time and difficult to bond. How old is your wire? Do you
keep your wire in a controlled atmosphere when not in use? Are your surfaces
clean from organic
contamination? Always plasma clean your devics if possible. Finally, have
your wire bonder serviced by a qualified service representative.
Bob Cole
The Aerospace Corporation