Silicon micro-mold
View Patent ↗The present invention describes a method for rapidly fabricating a robust 3-dimensional silicon-mold for use in preparing complex metal micro-components. The process begins by depositing a conductive metal layer onto one surface of a silicon wafer. A thin photoresist and a standard lithographic mask are then used to transfer a trace image pattern onto the opposite surface of the wafer by exposing and developing the resist. The exposed portion of the silicon substrate is anisotropically etched through the wafer thickness down to conductive metal layer to provide an etched pattern consisting of a series of rectilinear channels and recesses in the silicon which serve as the silicon micro-mold. Microcomponents are prepared with this mold by first filling the mold channels and recesses with a metal deposit, typically by electroplating, and then removing the silicon micro-mold by chemical etching.
1. A silicon mold for preparing metal micro-components, comprising:
a silicon substrate having a thickness, and substantially parallel top and bottom surfaces, said substrate having at least one pattern etched into said top surface comprising one or more etched channels or shapes wherein said channels or shapes comprise substantially vertical walls and terminate in substantially flat floor surfaces, said channels or shapes having features with lateral dimensions of less than 1 micron;
a silicon oxide release layer covering said substrate surfaces; and
an electrically conductive plating surface disposed at said flat floor surfaces.
2. The micro-mold of claim 1 , wherein said electrically conductive plating surface comprises one or more thin thermal or particle vapor deposited metal layers.
3. The micro-mold of claim 1 , wherein said electrically conductive plating surface is deposited by sputter deposition.
4. The micro-mold of claim 1 , wherein said conductive plating surface is deposited by electroplating.
5. The micro-mold of claim 1 , wherein said electrically conductive plating surface comprises one or more of the metals selected from the group consisting of the oxidation resistant noble metals listed in New IUPAC Groups 9, 10 and 11 of the Periodic Table of Elements, and alloy thereof.
6. The micro-mold of claim 5 , wherein said electrically conductive plating surface comprises a first metal layer consisting essentially of chromium.
7. The micro-mold of claim 1 , wherein said electrically conductive plating surface comprises a second metal layer consisting essentially of gold.