Condenser microphone array chip
A plurality of structures of condenser microphones is fabricated in a single condenser microphone array chip. The condenser microphone array chip includes a substrate having a plurality of openings serving as air cavities, a first insulating layer formed in the outer periphery of the openings, a first electrode layer stretched over each of the openings, a second insulating layer formed above the first electrode layer in the outer periphery of the openings, a second electrode layer formed above the second insulating layer relative to the first electrode layer via an air gap therebetween. The structures are connected via a plurality of bridges and separated via a plurality of channels therebetween. The channels circumvent the bridges so that at least the second insulating layer is partially removed from the channels. The bridges are formed using the second electrode layer serving as wiring for electrically connecting the structures of condenser microphones.
1. A condenser microphone array chip comprising:
a substrate having a plurality of openings running through its thickness;
a first insulating layer formed in an outer periphery of each of the openings of the substrate;
a first electrode layer which is formed above the first insulating layer and stretched over each of the openings of the substrate;
a second insulating layer which is formed above the first electrode layer in the outer periphery of each of the openings of the substrate;
a second electrode layer which is formed above the second insulating layer and which is positioned relative to the first electrode layer via an air gap therebetween,
wherein a plurality of structures of condenser microphones is formed using the first insulating layer, the first electrode layer, the second insulating layer, and the second electrode layer above the plurality of openings of the substrate with a plurality of air cavities,
wherein the plurality of structures of condenser microphones is connected in parallel via a plurality of bridges and two-dimensionally aligned on the substrate with a plurality of channels therebetween,
wherein the plurality of channels is formed to circumvent the plurality of bridges such that at least the second insulating layer is partially removed from the plurality of channels, and
wherein the plurality of bridges is formed using the second electrode layer serving as wiring connecting the plurality of structures of condenser microphones.
2. The condenser microphone array chip according to claim 1 , wherein the plurality of bridges includes the first insulating layer and the second insulating layer in order to support the wiring.
3. The condenser microphone array chip according to claim 1 , wherein the first insulating layer and the second insulating layer are removed in predetermined regions between the wiring and the substrate under the plurality of bridges.
4. The condenser microphone array chip according to claim 1 , wherein the substrate is composed of monocrystal silicon, and wherein the first electrode layer electrically conducts with the substrate so that the plurality of structures of condenser microphones is electrically connected to the substrate.
5. The condenser microphone array chip according to claim 1 , wherein the plurality of openings constituting air cavities is connected together so that the plurality of structures of condenser microphones shares a single large air cavity.