Polyimide is used as a spacer that also bonds together the elements that
it is spacing apart. This is achieved by constructing the spacer on at
least one of the wafers as is conventionally done, except that prior to
performing the final curing of the polyimide precursor to form the final
polyimide, the elements are aligned in a bonder and placed in contact
with a pressure of 40 grams per square millimeter at a temperature
slightly higher than the soft-bake temperature, as specified by the
manufacturer of the polyimide precursor, for few minutes to promote
tackiness. This holds the elements together, and the combined structure
is then baked to fully cure the polyimide precursor into polyimide and
complete the bonding.