Microfabrication methods for forming robust isolation and packaging

A method for fabricating a semiconductor device comprising:

• forming one or more trenches in a semiconductor substrate structure;
• forming a plurality of dielectric sidewalls for each of the one or more trenches;
• filling one of a metal and a polymer in each trench that has the plurality of dielectric sidewalls to form a trench isolation structure;
• and
• forming a plurality of active devices over the semiconductor substrate structure, wherein the plurality of active devices are electrically isolated by the trench isolation structure.

A method for forming a pattern in a deep trench comprising:

• forming a plurality of cavities in a semiconductor material and thereby leaving one or more material line structures interspersed with the plurality of cavities on a semiconductor membrane;
• depositing a thin-film layer on a surface of each of the one or more material line structures and a bottom of each of the plurality of cavities;
• and
• removing the one or more material line structures and thereby forming a trench that comprises a trench bottom on the semiconductor membrane, wherein the trench bottom comprises a thin-film layer pattern.

A self-packaging method comprising:

• forming an active device comprising a frontside and a backside, wherein the backside comprises a structured substrate;
• bonding a first wafer onto the backside of the active device to seal the structured substrate;
• forming one or more active structures on the front side of the active device;
• and
• bonding a second wafer onto the one or more formed active structures.