This invention provides method and apparatus for fabricating a MEMS
apparatus having a bulk element with hinges underneath. The bulk element
may comprise single-crystal silicon, fabricated by way of bulk
micromachining techniques. The hinges may be made of thin-films,
fabricated by way of surface micromachining techniques. A distinct feature
of the MEMS apparatus of the present invention is that by disposing the
hinges underneath the bulk element, the surface of the bulk element can be
maximized and the entire surface becomes usable (e.g., for optical beam
manipulation). Such a feature would be highly advantageous in making
arrayed MEMS devices, such as an array of MEMS mirrors with a high optical
fill factor. Further, by advantageously making use of both bulk and
surface micromachining techniques, a MEMS mirror thus produced is equipped
with a large and flat mirror along with flexible hinges, hence capable of
achieving a substantial rotational range at modest electrostatic drive
voltages.
