Hi Nigel - So I would recommend getting a copy of George Harman's "Wirebonding in Microelectronics", ISBN 0-930815-25-4. It is a great reference for the basics of wirebonding and has the baseline information you are looking for. Dave Hillman Collins Aerospace On Thu, Dec 19, 2019 at 2:46 AM Nigel Burtt <[log in to unmask]> wrote: > Thanks Dave and Joyce > > So my take-away from this advice is that Al wire-Au pad wedge bond is > certainly not a definite No-No, but: > > (a) the finish must use gold of the right purity and hardness > (b) the nickel coverage of the copper must be very good > (c) the surface roughness of the pads must be controlled > > As to whether the reliability of this is at least as good as Al wire-ENIG > pad, I guess some aging and testing would be needed? >