Semiconductor-based encapsulated infrared sensor and electronic device
An Al film is formed on a cap wafer and the Al film is patterned into a ring-shaped film. Dry etching is performed by using the ring-shaped film as a mask to form a drum portion enclosing a recess portion to provide a vacuum dome. After forming a depth of cut into the substrate portion of the cap wafer, the cap wafer is placed on a main body wafer having an infrared area sensor formed thereon. Then, the ring-shaped film of the cap wafer and the ring-shaped film of the main body wafer are joined to each other by pressure bonding to form a ring-shaped joining portion.
1. An electronic device, comprising:
a main body substrate having a plurality of cell regions in which at least one element is disposed;
a cap body placed on said main body substrate;
a cavity portion provided in a position having said element disposed therein and being located in at least one cell region of said plurality of cell regions, enclosed by said main body substrate and said cap body to be maintained in an atmosphere of reduced pressure or in an atmosphere of inert gas; and
a ring-shaped joining portion provided between said main body substrate and said cap body for isolating said cavity portion from external space,
wherein said electronic device comprises an infrared sensor having a thermoelectric transducer element as said at least one element, a support member for supporting said thermoelectric transducer element, and a second cavity portion formed below said support member, and
wherein said cap body is provided with a recess portion for forming said cavity portion and a drum portion enclosing the recess portion, and said main body substrate is provided with an engagement portion for engaging with said drum portion.
2. The electronic device according to claim 1 , wherein said second cavity portion is not provided with a pillar or a wall extending from said support member.
3. The electronic device according to claim 1 or 2 , wherein said second cavity portion is configured to communicate with said cavity portion.
4. The electronic device according to claim 1 , further comprising:
a first ring-shaped film formed on said main body substrate and enclosing said thermoelectric transducer element; and
a second ring-shaped film formed on said cap body,
wherein said ring-shaped joining portion is formed between said first and second ring-shaped films,
wherein the materials of said first and second ring-shaped films are selected from at least any one of Al, In, Cu, Au, Ag, Ti, W, Co, Ta, Al—Cu alloy, and an oxide film, and
wherein the materials of said first and second ring-shaped films are the same material with each other.
5. The electronic device according to claim 1 , wherein said cap body has a Si substrate and a semiconductor layer provided on the Si substrate and having a band gap of less than 1.1 eV.
6. The electronic device according to claim 1 or 5 , wherein the top layer of said cap body is configured by a Si layer having a diffraction pattern formed thereon to provide a Fresnel lens.
7. An electronic device, comprising:
a main body substrate having a plurality of cell regions in which at least one element is disposed;
a cap body placed on said main body substrate;
a first cavity portion provided in a position having said element disposed therein and being located in at least one cell region of said plurality of cell regions, enclosed by said main body substrate and said cap body to be maintained in an atmosphere of reduced pressure or in an atmosphere of inert gas; and
a ring-shaped joining portion provided between said main body substrate and said cap body for isolating said first cavity portion from external space,
wherein said electronic device comprises a support member for supporting said element, and a second cavity portion formed below said support member,
wherein said second cavity portion is configured to communicate with said first cavity portion, and
wherein said cap body is provided with a recess portion for forming said cavity portion and a drum portion enclosing the recess portion, and said main body substrate is provided with an engagement portion for engaging with said drum portion.
8. The electronic device according to claim 1 , wherein a connection portion between the drum portion of the cap body and the engagement portion of the main body substrate has a tapered surface.
9. The electronic device according to claim 1 , wherein a connection portion between the drum portion of the cap body and the engagement portion of the main body substrate has a stepped surface.