Every1,

Thanks for the info.  I tried the different suggestions.

Using a longer vapor HDMS primer did not solve the problem, I still got
the same amount of undercut, even after 45' of putting a vapor HDMS
primer.

The diluted solution of BHF/H2O2 did however work, a ratio of 3:1
diluted in DI water worked to reduce the undercut.

Cheers,
Steve.