Patent ID: 7115168

Claim:
A scanning localized evaporation apparatus comprising: (a) a base for supporting a substrate; (b) a multilevel mask assembly spaced above said base, comprising a multiplicity of masks vertically spaced from each other and having patterned openings therethrough, wherein said openings in the mask elements are vertically aligned in a manner resulting in a collimated evaporant beam; wherein said multilevel mask assembly further includes spacers disposed between said multiplicity of masks to separate said masks from each other; wherein said masks are comprised of electrically resistive materials and said spacers are insulators; (c) an evaporant source spaced above said mask assembly; (d) means for electrically heating each of said masks separately and individually such that each said mask can be electrically heated to a temperature that is substantially different from the temperature to which the other masks are heated; wherein said means for electrically heating and said insulator spacers together constitute means adapted to form a controlled temperature gradient across said multilevel mask assembly; and (e) means for heating said evaporant source to evaporate a vaporizable material into a stream which passes through said openings of mask elements in said mask assembly to deposit on the substrate.