Hi Ramesh,
From what you described, I think stiction is your problem: when you
"wash" the sacrificial layer away, the liquid trapped underneath your
beams will bend them down as you reduce the amount of the solvent (by
evaporation, in a vacuum chamber, etc.
This is an old problem in MEMS. Typical solutions are adding dimples
to your to-be-released structures or using a critical-point drying
system. Try to do a literature search on "stiction in MEMS".
Good luck,
Behraad