Semiconductor physical quantity sensor and method of manufacturing the same
First Claim
1. A semiconductor physical quantity sensor comprising:
- a substrate including a semiconductor layer, the semiconductor layer having therein a hollow being laterally extended;
a frame portion being provided to the semiconductor layer;
a beam-structure being arranged above the hollow, being connected to the frame portion, and having a movable electrode movable by action of physical quantity;
a fixed electrode being connected to the frame portion, confronting with the movable electrode, and being disposed on the hollow, the fixed electrode is made of a same material as the semiconductor layer to serve as a conductive member; and
at least one insulator provide between the frame portion and the fixed electrode, for electrically insulating the frame portion from the fixed electrode, wherein the insulator reaches he hollow so that whole of the fixed electrode is disposed on the hollow, whereby the fixed electrode is hung up the frame portion through the insulator so as to be supported by the frame portion through the insulator.
1 Assignment
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Accused Products
Abstract
A semiconductor physical quantity sensor, in which a beam-structure having a movable electrode and a fixed electrode confronted with the movable electrode are integrally formed in one substrate, having a new electric isolation structure. A semiconductor physical quantity sensor such as an acceleration sensor includes a silicon substrate; a laterally extending hollow formed in the silicon substrate; and a base plate portion defined below the hollow in the silicon substrate. A rectangular frame portion, a beam-structure having a movable electrode, and a fixed electrode is defined by the hollow and trenches. The fixed electrode confronts with the movable electrodes of the beam-structure. Trenches, in which electrical insulating material is buried, are formed between the movable electrode and the rectangular frame portion and between the fixed electrodes and the rectangular frame portion.
123 Citations
18 Claims
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1. A semiconductor physical quantity sensor comprising:
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a substrate including a semiconductor layer, the semiconductor layer having therein a hollow being laterally extended;
a frame portion being provided to the semiconductor layer;
a beam-structure being arranged above the hollow, being connected to the frame portion, and having a movable electrode movable by action of physical quantity;
a fixed electrode being connected to the frame portion, confronting with the movable electrode, and being disposed on the hollow, the fixed electrode is made of a same material as the semiconductor layer to serve as a conductive member; and
at least one insulator provide between the frame portion and the fixed electrode, for electrically insulating the frame portion from the fixed electrode, wherein the insulator reaches he hollow so that whole of the fixed electrode is disposed on the hollow, whereby the fixed electrode is hung up the frame portion through the insulator so as to be supported by the frame portion through the insulator. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
the substrate includes a trench being vertically extended and formed in the semiconductor layer;
the frame portion is divided by the hollow and the trench, and is positioned at sides of both the hollow and the trench;
the beam-structure is divided by the hollow and the trench; and
the fixed electrode is divided by the hollow and the trench.
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4. A semiconductor physical quantity sensor according to claim 1, wherein the substrate is an SOI substrate having a support substrate and the semiconductor layer with a buried insulating film interposed therebetween.
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5. A semiconductor physical quantity sensor according to claim 1, herein:
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the substrate includes a base plate portion being provided under the hollow and being divided by the hollow; and
the semiconductor physical quantity sensor further comprises a prop being vertically provided on the base plate portion, for supporting at least one of the beam-structure and the fixed electrode.
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6. A semiconductor physical quantity sensor according to claim 5, wherein the prop is made of insulating material.
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7. A semiconductor physical quantity sensor according to claim 1, wherein:
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the substrate is an SOI substrate having a support substrate and the semiconductor layer with a buried insulating film interposed therebetween, the support substrate has therein a primary hollow being laterally extended, the semiconductor layer include a trench being vertically extended, and the semiconductor layer and the primary hollow include a primary trench being vertically extended, wherein the semiconductor physical quantity sensor further comprises;
a primary frame portion being provided to the semiconductor layer by being divided by the primary hollow and the primal trench, and is positioned at sides of both the primary hollow and the primary trench;
a primary oscillatory mass being arranged above the hollow by being divided by the primary hollow and the primary trench, being connected to the primary frame portion, and having a primary movable electrode; and
a primary excitation fixed electrode being divided by the hollow and the trench formed in the semiconductor layer, being connected to the primary frame portion and confronting with the primary movable electrode.
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8. A semiconductor physical quantity sensor according to claim 1, wherein the insulator is provided in insulating trench provided at least one of between the frame portion and the movable electrode, and between the frame portion and the fixed electrode.
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9. A semiconductor physical quantity sensor according to claim 8, wherein the insulator is made up of one of insulating material and a material covered with insulating material.
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10. A semiconductor physical quantity sensor according to claim 1, wherein said insulator extends from a surface of the semiconductor layer to the hollow so as to penetrate the semiconductor layer.
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11. A semiconductor physical quantity sensor according to claim 10, wherein the insulator has a center protruding in an extending direction of the fixed electrode.
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12. A semiconductor physical quantity sensor according to claim 10, wherein the insulator is protruded into the hollow.
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13. A semiconductor physical quantity sensor according to claim 3, wherein said semiconductor layer is disposed on the substrate, and the hollow is formed in the semiconductor layer so that the hollow communicates with external of the sensor only through the trench.
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14. A semiconductor physical quantity sensor according to claim 13, wherein said semiconductor layer is disposed on the substrate with an insulating layer interposed therebetween.
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15. A semiconductor physical quantity sensor according to claim 14, wherein said hollow exposes the insulting layer so that the insulating layer faces the beam structure with the hollow interposed therebetween.
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16. A semiconductor physical quantity sensor according to claim 13, wherein said semiconductor layer and the substrate constitute a single crystal semiconductor, and the hollow is a cavity formed in the single crystal semiconductor.
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17. A semiconductor physical quantity sensor comprising:
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a semiconductor substrate being made up of single layer, having therein a hollow being laterally extended, having a trench being vertically extended and reaching the hollow, and having a base plate portion being divided by the hollow and being positioned under the hollow;
a frame portion being positioned at sides of the both the hollow and the trench by being divided by the hollow and the trench;
a beam-structure being positioned above the hollow by being divided by the hollow and the trench, being connected to the frame portion, and having a movable electrode movable by action of physical quantity;
a fixed electrode being positioned above the hollow by being divided by the hollow and the trench, being connected to the frame portion and confronting with the movable electrode; and
an insulator buried in insulating trenches provided between the frame portion and the movable electrode, and between the Fame portion and the fixed electrode, wherein said insulating trench reach the hollow.
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18. A semiconductor physical quantity sensor comprising:
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an SOI substrate having a support substrate and the semiconductor layer with a buried insulating film interposed therebetween, the support substrate having a primary hollow being laterally extended, the buried insulating film having a through hole, the semiconductor layer having a trench and a secondary trench being vertically extended, the semiconductor layer having a hollow and a secondary hollow being laterally extended, and the semiconductor layer and the primary hollow having primary trench being vertically extended;
a primary frame portion being divided by the primary hollow and the through hole, and being positioned at sides of the primary hollow, the primary trench and the through hole;
a primary oscillatory mass being divided by the primary hollow, the primary trench and the through hole, being connected to the primary frame portion, and having a primary movable electrode;
a primary excitation fixed electrode being divided by the hollow and the trench formed in the semiconductor layer, being connected to the primary frame portion, and confronting -with the primary movable electrode;
a secondary frame portion being divided by the secondary hollow and the secondary trench, and being positioned at sides of the both the secondary hollow and the secondary trench, for supporting the primary movable electrode of the primary oscillatory mass;
a beam-structure being divided by the secondary hollow and the secondary trench, being positioned above the secondary , being connected to the secondary frame portion, and having a secondary movable electrode movable by action of physical quantity;
a secondary excitation fixed electrode being divided by the secondary hollow and the secondary trench, being positioned above the secondary hollow, being connected to the secondary frame portion, and confronting with the secondary movable electrode;
a first insulator being buried in insulating trenches provided between the primary movable electrode and the second frame portion, and between the primary excitation fixed electrode and the primary frame port on; and
a second insulator being buried in insulating trenches provided between the secondary movable electrode and the secondary frame portion, and between the secondary excitation fixed electrode and the secondary frame portion, wherein the primary hollow communicates with the hollow and the secondary hollow formed in the semiconductor layer through the hole formed in the buried insulating film.
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Specification