Methods for forming openings having predetermined shapes in a substrate
and apparatuses with these openings. The methods may be used to form
assemblies which include the substrate with its openings and elements
which are disposed in the openings. In one example of a method, each of
the elements include an electrical component and are assembled into one
of the openings by a fluidic self assembly process. In an particular
example of a method to create such an opening, the substrate is etched
through a first patterned mask and is later etched through a second
patterned mask. Typically, the second patterned mask is aligned relative
to the opening created by etching through the first patterned mask and
has an area of exposure which is smaller than an area of exposure through
the first patterned mask. In another example of a method, a
photosensitive material is exposed through a patterned mask to oblique
sources of light such that some of the light impinges into a first
portion of the photosensitive material which is under the patterned mask,
and the patterned mask and a second portion of the photosensitive
material, which is under the patterned mask, is removed. In another
example of a method, an opening in a first layer, which comprises silicon
dioxide, is formed by depositing a second layer over the first layer and
depositing a tungsten layer over the second layer. The tungsten and
second layers are patterned to expose a portion of the first layer, and
this portion is etched. Various apparatuses which may be made using these
methods are also described.