Hermetically sealed MEMS device and its fabrication

• Main Authors: Ehmke, John Charles, Ararao, Virgil Cotoco
• Format: Patent
• Language: English
• Published: 01.10.2019
• Subjects: BASIC ELECTRIC ELEMENTS; ELECTRIC SOLID STATE DEVICES NOT OTHERWISE PROVIDED FOR; ELECTRICITY; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MICROSTRUCTURAL DEVICES OR SYSTEMS, e.g. MICROMECHANICALDEVICES; MICROSTRUCTURAL TECHNOLOGY; NANOTECHNOLOGY; OPTICAL ELEMENTS, SYSTEMS, OR APPARATUS; OPTICS; PERFORMING OPERATIONS; PHYSICS; PROCESSES OR APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTUREOR TREATMENT OF MICROSTRUCTURAL DEVICES OR SYSTEMS; SEMICONDUCTOR DEVICES; SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; TRANSPORTING

In described examples, a hermetic package of a microelectromechanical system (MEMS) structure includes a substrate having a surface with a MEMS structure of a first height. The substrate is hermetically sealed to a cap forming a cavity over the MEMS structure. The cap is attached to the substrate surface by a vertical stack of metal layers adhering to the substrate surface and to the cap. The stack has a continuous outline surrounding the MEMS structure while spaced from the MEMS structure by a distance. The stack has: a first bottom metal seed film adhering to the substrate and a second bottom metal seed film adhering to the first bottom metal seed film; and a first top metal seed film adhering to the cap and a second top metal seed film adhering to the first top metal seed film.