> ...Can anyone tell me how to manufacture cantilever
> beam using Focused Ion Beam...

Ravi, there are several ways you could use a FIB to make cantilevers. And
there must be references in the literature of people making MEMS structures
with FIBs, though I don't have any at my fingertips.

Regardless of which method you pursue, I think you'll have to use a
sacrificial material for a temporary support. You'll have to get rid of this
sacrificial material later, probably after FIBing.

Method 1: Etch/Pattern only
* obtain substrate with sacrificial material and structural
  material already deposited
* etch/pattern away unwanted structural material
* remove sacrificial material

method 2 and 3 are useful if you have deposition capability

Method 2: Deposit structural material
* obtain substrate with sacrificial material
* (optional) pattern "anchor" in sacrificial material
* deposit structural material in desired pattern (will be
  a negative image of Method 1)
* remove sacrificial material

Method 3: Deposit sacrificial and structural materials
* obtain substrate
* deposit sacrificial material in desired pattern
* deposit structural material in desired pattern
* remove sacrificial material

Bill Eaton, Ph.D.
Materials & Analysis Manager
NP Photonics
5706 Corsa Avenue, Suite 100
Westlake Village, CA  91362
Voice:  (818) 991-7044 x211
eFax:   (503) 214-5559
mailto://bill@npphotonics.com
www.parvenutech.com