Microfabrication using germanium-based release masks

A method for forming released mechanical structures on the same substrate as interconnections, the method comprising the steps of:

• (a) providing a substrate having interconnections, a first surface, and a sacrificial layer, said sacrificial layer including silicon dioxide;
• (b) depositing a protective layer including germanium onto said first surface;
• (c) defining one or more mechanical structures into said first surface, thereby exposing a portion of said sacrificial layer by
• (c1) removing a portion of the protective layer overlying said first surface leaving remaining portions of said protective layer, and
• (c2) etching a trench from said first surface to said sacrificial layer;
• (d) releasing said mechanical structure from said sacrificial layer by etching at least a portion of said sacrificial layer using an etchant including hydrogen fluoride, thereby forming a structure-released substrate;
• and
• (e) removing remaining portions of said protective layer including germanium.

A method for forming released mechanical structures on the same substrate as interconnections, the method comprising the steps of:

• (a) providing a substrate having a first surface, interconnections, a sacrificial layer, and one or more defined mechanical structures affixed to the sacrificial layer;
• (b) depositing a mask layer including germanium onto said first surface;
• (c) photolithographically defining a release region enclosing at least a portion of a defined mechanical structure;
• (d) etching a portion of said mask layer including germanium from said release region to expose said first surface and leave remaining portions of said layer, wherein the etchant is selected from one of the following list:
• a plasma etch containing fluorine, a solution containing hydrogen peroxide;
• (e) releasing said mechanical structure from said sacrificial layer by etching at least a portion of said sacrificial layer using an etchant including hydrogen fluoride, thereby forming a structure-released substrate;
• and
• (f) removing remaining portions of said layer including germanium.

A method for forming released mechanical structures on the same substrate as interconnections, the method comprising the steps of:

• (a) providing a substrate having interconnections, a first surface, and a sacrificial layer;
• (b) defining one or more mechanical structures (by etching trenches from said first surface to said sacrificial layer) into said first surface, thereby exposing a portion of said sacrificial layer;
• (c) selectively depositing a layer including germanium onto said substrate, wherein exposed portions of said sacrificial layer serve as a masking surface for said selective deposition;
• (d) releasing said mechanical structure from said sacrificial layer by etching at least a portion of said sacrificial layer using an etchant including hydrogen fluoride, thereby forming a structure-released substrate;
• (e) substantially removing remaining portions of said mask layer including germanium.