Wafer-level MEMS packaging
AssigneeDALSA Semiconductor Inc.
InventorLuc Ouellet
Life of this patent
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Abstract
A competitive, simple, single-substrate wafer-level packaging technique capable of creating a vacuum-sealed protective cavity around moving or other particular components of a MEMS is described. The technique uses common semiconductor materials, processing steps and equipment to provide a stable vacuum environment of, for example less than 1 Pa, in a sealed cavity. The environment protects components of the MEMS against micro-contamination from particles and slurry of a waver dicing process and against fluctuations of atmospheric condition to ensure long term reliability.
Claims17
A process for fabricating an integrated, wafer-level protective cap on a micro-electronic device comprising:
- depositing first and second layers of sacrificial material during a fabrication stage of said device, said first and second layers of sacrificial material being selectively patterned;
- depositing and patterning an encapsulation structure over said second layer of sacrificial material;
- removing said patterned sacrificial material through the encapsulation structure by a vapor etch to form said micro-electronic device;
- and
- depositing a sealing layer over said encapsulation structure.
A process for fabricating an integrated wafer-level protective cap for a micro-Electro-Mechanical-System (MEMS) device comprising:
- depositing and patterning a pad oxide layer on a silicon substrate;
- depositing and patterning a polysilicon layer on said pad oxide layer and silicon substrates;
- depositing and patterning a first layer of a sacrificial material;
- depositing and patterning structured In-Situ-Doped-Polysilicon (ISDP) on said first layer of sacrificial materials;
- patterning and deep etching said ISDP;
- depositing and patterning a second layer of sacrificial material;
- depositing an encapsulation structure over said patterned second layer of sacrificial material;
- patterning said encapsulation structure;
- selectively removing said first and second layers of sacrificial material to create said MEMS;
- and
- depositing, under vacuum, a sealing layer over said encapsulation structure.
Dependencies are inferred from the claim text.