Dear Sirs:
    We want to etch a V-groove with TMAH.But our experiments showed
that the surface is very rough with many hilllocks. By add IPA or
(NH4)2S2O3, the surface is still rough.And the concentration of the
TMAH we used is 5%(wt)~22%(wt).
    Would someone kindly to tell us how to have a V-groove without
hilllocks by using TMAH?
    Thanks a lot.

    Best Regards!

                       Yours Sincerely:LuoYuan
                           Aug.8,2001