Mems device with a cap layer having gaps and method of manufacturing a mems device
AssigneeMurata Manufacturing Co., Ltd.
InventorsKonsta HANNULA, Jussi OKSANEN, Jussi AAV
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Abstract
A MEMS device is provided that includes a cap layer and a device layer. The cap layer includes a cap wafer made of electrically insulating material, and the device layer includes at least one seismic element. Moreover, the cap layer includes at least one silicon-filled portion at a first face of the cap layer facing the device layer, and at least one of said at least one silicon-filled portion includes a gap that locally increases distance from the cap layer to the at least one seismic element in the device layer.
Claims20
A MEMS device comprising:
- a cap layer including a cap wafer formed from an of electrically insulating material;
- and
- a device layer comprising at least one seismic element,
- wherein the cap layer further comprises at least one silicon-filled portion at a first face of the cap layer that faces the device layer,
- wherein the at least one silicon-filled portion comprises a gap that is a recessed area in the respective silicon-filled portion that locally increases in distance from the cap layer to the at least one seismic element.
A method of manufacturing a MEMS device, the method comprising:
- providing a three-dimensionally patterned silicon mold;
- depositing glass or applying heat-softened glass on the three-dimensionally patterned silicon mold to create a cap wafer with a three-dimensionally patterned first face;
- removing at least part of the silicon mold by at least one of grinding and chemical-mechanical polishing;
- if remaining portions of the silicon mold are removed by etching, depositing a layer of polysilicon on the first face of the cap wafer, and thinning the deposited layer of polysilicon by at least one of grinding and chemical-mechanical polishing;
- wherein the first face of the cap layer comprises a flat surface comprising one or more silicon-filled portions and one or more areas of exposed glass;
- wherein the method further comprises:
- at least partially recessing at least one of the one or more silicon-filled portions below the flat surface at the first face of the cap layer by etching to generate at least one gap;
- and
- bonding the cap wafer at the first face to a device layer such that the at least one gap is superposed with one or more seismic elements comprised in the device layer.
Dependencies are inferred from the claim text.