Multilevel imprint lithography

A method for making a multiplexer/demultiplexer in nanoscale circuits by an imprinting and lift-off process, said method comprising:

• providing a substrate with at least one bottom communication wire on a major surface thereof;
• forming a first polymer layer on said major surface of said substrate, said first polymer layer having a first thickness;
• forming a second polymer layer on said first polymer layer, said second polymer layer having a second thickness and capable of dissolving at a faster rate in a solvent than said first polymer;
• providing a mold having a plurality of wire-like protrusions, portions of each protrusion having either a first height or a second height, wherein said first height is greater than said second height, wherein said first height is equal to the total of said first and second thickness and wherein said second height is less than said second thickness;
• impressing said wire-like protrusions of said mold into said first and second polymer layers such that said first height penetrates said first and second polymers to said bottom communication wire to thereby create a plurality of shallow recesses and a plurality of deep recesses;
• blanket-depositing a metal layer on said second polymer and in said shallow and deep recesses;
• removing said second polymer and said metal layer thereon, thereby leaving metal in said shallow recesses that does not make electrical contact said bottom communication wire and leaving metal in said deep recesses that does make electrical contact with said bottom communication wire.

A method for making a multiplexer/demultiplexer in nanoscale circuits by an imprinting and etch process, said method comprising:

• (a) providing a substrate with a major surface;
• (b) forming a conductive layer on said major surface of said substrate;
• (c) forming a polymer layer on said conductive layer, said polymer layer having a thickness;
• (d) providing a mold having a planar surface and a plurality of wire-like recesses, portions of each recess having either a first depth or a second depth, wherein said first depth is greater than said second depth, wherein said first depth is equal or greater than said polymer thickness and wherein said second depth is less than said polymer thickness;
• (e) impressing said mold into said polymer layer such that said planar surface penetrates said polymer to said conductive layer to thereby create a plurality of wire-like polymer protrusions with multi-level relief, portions of each protrusion having either a first height or a second height;
• (f) transferring the multi-level relief of said imprinted polymer layer into said conductive layer by single or multiple etch processes, to form conductive wires with multi-level relief, portions of each wire have a first height or a second height, wherein said first height is greater than said second height;
• (j) forming an insulating layer on top of said conductive wires by deposition or growth processes;
• (k) planarizing said insulating layer at the level of the topmost conductive wire portions of said first height, to leave a plurality of conductive wires covered by said insulating layer except exposed at those portions of said first height;
• (l) forming a plurality of upper communication wires supported by said planarized insulating layer, that make electrical contact to said lower conductive wires only at those portions of said first height not covered by said insulating layer.