Three-dimensional structures of arbitrary shape are fabricated
on the surface of a substrate through a series of processing steps wherein a monolithic
structure is fabricated in successive layers. A first layer of photoresist material
is spun onto a substrate surface and is exposed in a desired pattern corresponding
to the shape of a final structure, at a corresponding cross-sectional level in
the structure. The layer is not developed after exposure; instead, a second layer
of photoresist material is deposited and is also exposed in a desired pattern.
Subsequent layers are spun onto the top surface of prior layers and exposed, and
upon completion of the succession of layers each defining corresponding levels
of the desired structure, the layers are all developed at the same time leaving
the three-dimensional structure.