3D mems device with hermetic cavity

A micro-electro-mechanical system (MEMS) device comprising:

• a silicon-on-insulator (SOI) MEMS wafer including an SOI MEMS structure, the SOI MEMS wafer including a MEMS device layer, a MEMS handle layer and a MEMS insulating layer interposed between the MEMS device layer and the MEMS handle layer and having opposed first and second sides;
• a top cap wafer and a bottom cap wafer respectively bonded relative to the first side and the second side of the SOI MEMS wafer, respectively, the SOI MEMS structure being positioned in a cavity between the top cap wafer and the bottom cap wafer such that the SOI MEMS structure moves within the cavity, at least one of the top cap wafer and the bottom cap wafer being a silicon-on-insulator (SOI) cap wafer comprising a cap device layer, a conductive cap handle layer and a cap insulating layer interposed between the cap device layer and the conductive cap handle layer, and wherein the conductive cap handle layer has an outer side with outer electrical contacts, and the cap device layer includes at least one sensing electrode connected to at least one of the outer electrical contacts;
• and
• an electrically conductive path extending through an insulated feedthrough of the conductive cap handle layer, through the cap insulating layer and through the cap device layer of the SOI cap wafer, the electrically conductive path establishing an electrical connection between at least one of the outer electrical contacts and said MEMS structure that includes at least a portion of the MEMS device layer and the conductive cap handle layer.

A micro-electro-mechanical system (MEMS) device comprising:

• a MEMS wafer including a MEMS structure, the MEMS wafer having opposed first and second sides;
• a top cap wafer and a bottom cap wafer respectively bonded to the first side and the second side of the MEMS wafer, the top cap wafer, the bottom cap wafer and the MEMS wafer being stacked along a stacking axis to form at least one hermetic cavity enclosing the MEMS structure, at least one of the top cap wafer and the bottom cap wafer being a silicon-on-insulator (SOI) cap wafer comprising a conductive silicon cap handle layer, a conductive silicon cap device layer and a cap insulating layer interposed between the cap device layer and the cap handle layer, the SOI cap wafer having a plurality of outer electrical contacts, the cap device layer including at least one sensor electrode to sense a motion of the MEMS structure and at least one drive electrode to actuate motion of the MEMS structure;
• and
• an electrically conductive path extending within an insulated feedthrough of the conductive silicon cap handle layer, through the cap insulating layer, and within the conductive silicon cap device layer of the SOI cap wafer, the electrically conductive path establishing an electrical connection between at least one of the plurality of the outer electrical contacts and said MEMS structure.

A micro-electro-mechanical system (MEMS) device comprising:

• a MEMS wafer including a MEMS structure, the MEMS wafer having opposed first and second sides;
• a top cap wafer and a bottom cap wafer respectively bonded relative to the first side and the second side of the MEMS wafer to form a wafer stack, at least the top cap wafer, the bottom cap wafer and the MEMS wafer being stacked to form at least one cavity wherein the MEMS structure is within the cavity, the top cap wafer and the bottom cap wafer respectively being first and second silicon-on-insulator (SOI) cap wafers, each SOI cap wafer comprising a conductive silicon cap device layer, a conductive silicon cap handle layer and a cap insulating layer interposed between the conductive silicon cap device layer and the conductive silicon cap handle layer;
• and
• an electrically conductive path extending through an insulated feedthrough of the conductive silicon cap handle layer, through the cap insulating wafer, and through the conductive silicon cap device layer of the top SOI cap wafer and through at least a portion of the MEMS wafer to electrically contact the cap device layer of the bottom SOI cap wafer, the electrically conductive path establishing an electrical connection between a first outer electrical contact and the bottom cap device layer and a further electrically conductive path establishing an electrical connection between a second outer electrical contact and said MEMS structure.

A micro-electro-mechanical system (MEMS) device comprising:

• a MEMS wafer including a MEMS structure, the MEMS wafer having opposed first and second sides;
• a top cap wafer and a bottom cap wafer respectively bonded on the first side and the second side of the MEMS wafer, respectively, the top cap wafer, the bottom cap wafer and the MEMS wafer being stacked along a stacking axis to form at least one hermetic cavity that houses the MEMS structure, at least one of the top cap wafer and the bottom cap wafer being a silicon-on- insulator (SOI) cap wafer comprising a conductive silicon cap handle layer, a conductive silicon cap device layer and a cap insulating layer interposed between the conductive silicon cap device layer and the conductive silicon cap handle layer, the SOI cap wafer having a plurality of outer electrical contacts, the conductive silicon cap device layer including at least one sensor electrode to sense a motion of the MEMS structure and at least one drive electrode to actuate motion of the MEMS structure;
• and
• an electrically conductive path extending within an insulated feedthrough of the conductive silicon cap handle layer, through the cap insulating layer, and within the conductive silicon cap device layer of the SOI cap wafer, the insulated feedthrough defined by a trench extending through an entire thickness of the conductive silicon cap handle layer that provides an electrical connection between at least one of the plurality of the outer electrical contacts and said MEMS structure.

A micro-electro-mechanical system (MEMS) device comprising:

• a MEMS wafer including a MEMS structure, the MEMS wafer having opposed first and second sides;
• a top cap wafer and a bottom cap wafer respectively bonded relative to the first side and the second side, respectively, of the MEMS wafer to form a wafer stack, at least the top cap wafer, the bottom cap wafer and the MEMS wafer being stacked to form at least one cavity wherein the MEMS structure is within the cavity, the top cap wafer and the bottom cap wafer, respectively, being a top silicon-on-insulator (SOI) cap wafer and a bottom SOI cap wafer, the top SOI cap wafer and the bottom SOI cap wafer each comprising a conductive silicon cap device layer, a conductive silicon cap handle layer and a cap insulating layer interposed between the conductive silicon cap device layer and the conductive silicon cap handle layer;
• and
• a first insulated electrically conductive path extending through an insulated feedthrough of the conductive silicon cap handle layer, through the cap insulating wafer, and through the conductive silicon cap device layer of the top SOI cap wafer and through at least a portion of the MEMS wafer to electrically contact the conductive silicon cap device layer of the bottom SOI cap wafer, the electrically conductive path establishing an electrical connection between a first outer electrical contact and the bottom cap device layer and a second electrically conductive path establishing an electrical connection between a second outer electrical contact and said MEMS structure.