I am having a problem of measuring 0.5 micron Gold ( + Cobalt and slight
Nickel i.e 98 % Gold and density of 17.6 gms/cc) over 8 microns Nickel ( pure)
over 35 microns Copper over FR-4 laminate.
On production we use Promethium isotope on Betascope and calibrate on stds.
either side of 0.5 microns.
When the same is measured at my customers XRF he finds the gold to be
0.2-0.3 microns and Nickel at 22 microns. He uses Pure
Gold standards and on full copper.
Could any expert enlighten me - AS far as the
certainity of 0.5 microns goes we are very sure - at it for 15 years now.Cross
check with gold consumption and weight gain on samples etc. etc.
We also cross check on other betascopes - no
problem.
I have a feeling that since standards used for
XRF differ in composition - top layer as well as substrate - the secondary
emissions on XRF do not tally and hence difference.
But then I also need a
solution
Await help
Anil Kher
micro interconnexion pvt. ltd.
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