Acceleration sensor and process for the production thereof
First Claim
1. An acceleration sensor comprising:
- a first substrate formed of a silicon material which is used as a conductive material;
a second substrate provided on the lower side of said first substrate and electrically insulated from the first substrate;
said first substrate including;
a support beam having a mass portion forming capacitive electrodes for displacement in a parallel direction to a surface of said second substrate according to the degree of acceleration, a fixed portion for fixing said support beam to said second substrate and a support portion for intermediately supporting said mass portion to said fixed portion, an insulating groove extending through a thickness of said first substrate around the entire periphery of said support beam, and stationary blocks forming capacitive electrodes defined by said insulating groove on the outer sides of said support beam separately across said insulating groove and fixed to said second substrate; and
gap means forming a gap space in order to space said mass portion and said supporting portion from a surface of said second substrate; and
said second substrate being separated from said first substrate by an insulating layer which is at least provided on the lower side of said fixed portion and stationary blocks.
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Abstract
A single crystal silicon substrate (1) is bonded through an SiO2 film (9) to a single crystal silicon substrate (8), and the single crystal silicon substrate (1) is made into a thin film. A cantilever (13) is formed on the single crystal silicon substrate (1), and the thickness of the cantilever (13) in a direction parallel to the surface of the single crystal silicon substrate (1) is made smaller than the thickness of the cantilever in the direction of the depth of the single crystal silicon substrate (1), and movable in a direction parallel to the substrate surface. In addition, the surface of the cantilever (13) and the part of the single crystal silicon substrate (1), opposing the cantilever (13), are, respectively, coated with an SiO2 film (5), so that an electrode short circuit is prevented in a capacity-type sensor. In addition, a signal-processing circuit (10) is formed on the single crystal silicon substrate (1), so that signal processing is performed as the cantilever (13) moves.
39 Citations
40 Claims
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1. An acceleration sensor comprising:
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a first substrate formed of a silicon material which is used as a conductive material;
a second substrate provided on the lower side of said first substrate and electrically insulated from the first substrate;
said first substrate including;
a support beam having a mass portion forming capacitive electrodes for displacement in a parallel direction to a surface of said second substrate according to the degree of acceleration, a fixed portion for fixing said support beam to said second substrate and a support portion for intermediately supporting said mass portion to said fixed portion, an insulating groove extending through a thickness of said first substrate around the entire periphery of said support beam, and stationary blocks forming capacitive electrodes defined by said insulating groove on the outer sides of said support beam separately across said insulating groove and fixed to said second substrate; and
gap means forming a gap space in order to space said mass portion and said supporting portion from a surface of said second substrate; and
said second substrate being separated from said first substrate by an insulating layer which is at least provided on the lower side of said fixed portion and stationary blocks. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. An acceleration sensor comprising:
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a substrate which is selected from the group consisting of an insulating material and oxidized semiconductor material;
a support beam which includes a mass portion forming a predetermined mass and first capacitive electrodes on side surfaces of said mass portion, a fixed portion for fixing said support beam to said substrate and a thin support portion for intermediately connecting between said mass portion and said fixed portion;
a pair of stationary blocks arranged on both sides of said support beam separately across an air gap and fixed to said substrate, said stationary blocks provided with second capacitive electrodes on the opposite sides of first capacitive electrodes of said mass portion;
gap means forming a gap space in order to space said mass portion and thin support portion from a surface of said substrate; and
said mass portion being displace in a parallel direction to the surface of said substrate according to the degree of acceleration and said support beam and stationary blocks formed of a silicon material which is used as a conductive material and electrically insulated from said substrate. - View Dependent Claims (9, 10, 11, 12, 13)
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14. An acceleration sensor comprising:
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A. a first single crystalline silicon substrate having a first surface and a second surface opposite said first surface;
B. a second single crystalline silicon substrate connected to a side of said first surface of said first single crystalline silicon substrate with an insulating layer interposed therebetween;
C. said first single crystalline silicon substrate including;
i. a movable beam defined by a trench which is disposed to surround said movable beam and extend from said second surface to said first surface, said movable beam being supported by said second single crystalline silicon substrate through said insulating layer to be displaceable in a direction parallel to said first surface of said first single crystalline silicon substrate, ii. a stationary block disposed to be spaced apart from said movable beam via said trench, facing said movable beam to form a pair of capacitive electrodes with said movable beam, and fixed to said second single crystalline silicon substrate; and
D. a signal-processing circuit element for carrying out a processing operation based on a change of a capacitance between said capacitive electrodes. - View Dependent Claims (15, 16, 17, 18, 19)
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20. An acceleration sensor comprising:
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A. a first single crystalline silicon substrate having a first surface and a second surface opposite said first surface;
B. a second single crystalline silicon substrate connected to a side of said first surface of said first single crystalline silicon substrate with an insulating layer interposed therebetween;
C. said first single crystalline silicon substrate being divided by a trench extending from said second surface to said first surface;
i. a movable beam portion surrounded by said trench, said movable beam portion being supported by said second single crystalline silicon substrate through said insulating layer to be displaceable in a direction parallel to said first surface of said first single crystalline silicon substrate, said movable beam portion having a movable electrode, ii. a stationary portion disposed to be spaced apart from said movable beam via said trench, having a stationary electrode which faces said movable beam via said trench to form a pair of capacitive electrodes with said movable electrode, and fixed to said second single crystalline silicon substrate; and
D. an insulator covering at least one of a surface of said movable electrode and a surface of said stationary electrode. - View Dependent Claims (21)
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- 22. A semiconductor dynamic amount sensor comprising a movable portion and a stationary portion located on a side of a support, the movable portion and the stationary portion being formed of the same semiconductor material, said support being present on an insulating layer formed on a surface of a substrate, said movable portion and said stationary portion and said substrate being electrically separated through said insulating layer, wherein at least one of the facing surfaces of said movable portion and said stationary portion facing with each other is provided with a protrusion which protrudes toward the opposite-facing surface thereof in a direction parallel with the surface of the substrate and shortens a gap between said movable portion and said stationary portion there, wherein said movable portion can be moved in a direction parallel with said surface of said substrate.
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28. A semiconductor dynamic amount sensor comprising:
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a substrate;
an insulating layer formed on a surface of said substrate;
a support made of an insulating substrate and formed on said insulating layer;
a movable portion and a stationary portion provided on a side of said support, each being formed of the same semiconductor substrate by etching and being separated with each other in a direction parallel with a surface of said support, said movable portion and said stationary portion and said substrate being electrically separated through said insulating layer, said movable portion being able to be moved in a direction parallel with said surface of said substrate; and
a protrusion provided with at least one of the facing surfaces of said movable portion and said stationary portion facing with each other, protruding toward the opposite-facing surface thereof in the direction parallel with said surface of said substrate, and ensuring a minimum gap between said facing surfaces even when said facing surfaces come close. - View Dependent Claims (29, 30, 31, 32, 33, 36, 39)
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34. A semiconductor dynamic amount sensor comprising a movable portion and a stationary portion located on a side of a support and each formed of the same semiconductor material, said support being present on an insulating layer formed on a surface of a substrate said movable portion and said stationary portion and said substrate being electrically separated through said insulating layer,
wherein the facing surfaces of said stationary portion and said movable portion facing each other are provided with a stationary electrode and a movable electrode respectively, said movable portion being able to be moved in a direction parallel with said surface of said substrate and a portion or portions of said facing surfaces of said stationary portion and said movable portion with said stationary electrode and said movable electrode protrudes or protrude in a direction in parallel with the surface of said support such that said stationary portion and said movable portion have a first gap and a second gap smaller than said first gap between said facing surfaces.
Specification