Sensors and sensor systems
The sensor design addresses noise and accuracy issues by using a fixed-potential conductive member and differential detection, enhancing sensitivity and precision in gas detection.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- KK TOSHIBA
- Filing Date
- 2023-03-02
- Publication Date
- 2026-05-26
AI Technical Summary
Existing sensors face challenges in improving characteristics such as signal noise and accuracy during gas detection due to temperature rise and large current supply.
A sensor design with a fixed-potential conductive member between the resistive and conductive layers to suppress noise, combined with a configuration that allows high conductive layer current for effective heating and low resistive layer current for sensitive detection, along with a second element for reference and differential detection.
The design achieves high accuracy and sensitivity in gas detection by effectively suppressing noise and maintaining temperature uniformity, enabling precise detection of gas state and concentration.
Smart Images
Figure 0007865901000001 
Figure 0007865901000002 
Figure 0007865901000003
Abstract
Description
Technical Field
[0001] Embodiments of the present invention relate to a sensor and a sensor system.
Background Art
[0002] For example, there is a sensor for detecting gas. In the sensor, improvement of characteristics is desired.
Prior Art Documents
Patent Documents
[0003]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0004] Embodiments of the present invention provide a sensor and a sensor system capable of improving characteristics.
Means for Solving the Problems
[0005] According to an embodiment of the present invention, a sensor includes an element portion including a first base and a first element; the first element includes a first fixing member fixed to the first base, a first connection member supported by the first fixing member, and a first film portion supported by the first connection member; a second direction from the first fixing member to the first film portion intersects a first direction from the first base to the first fixing member; a first gap is provided between the first base and the first film portion; the first film portion includes a first resistance layer, a first conductive layer, and a first conductive member provided between the first resistance layer and the first conductive layer; a potential of the first conductive member is fixed; and a first electrical resistance of the first resistance layer changes according to a state of a detection target around the first element.
Brief Description of the Drawings
[0006] [Figure 1]Figure 1 is a schematic cross-sectional view illustrating a sensor according to the first embodiment. [Figure 2] Figures 2(a) to 2(c) are schematic cross-sectional views illustrating a sensor according to the first embodiment. [Figure 3] Figure 3 is a schematic plan view illustrating a sensor according to the first embodiment. [Figure 4] Figure 4 is a schematic cross-sectional view illustrating a part of the sensor according to the first embodiment. [Modes for carrying out the invention]
[0007] The embodiments of the present invention will be described below with reference to the drawings. Drawings are schematic or conceptual, and the relationships between the thickness and width of each part, as well as the ratios of the sizes of different parts, are not necessarily identical to those of reality. Even when representing the same part, the dimensions and ratios may be depicted differently in different drawings. In this specification and in each figure, elements similar to those described above are denoted by the same reference numerals with respect to previously shown figures, and detailed explanations are omitted as appropriate.
[0008] (First Embodiment) Figure 1 is a schematic cross-sectional view illustrating a sensor according to the first embodiment. Figures 2(a) to 2(c) are schematic cross-sectional views illustrating a sensor according to the first embodiment. Figure 3 is a schematic plan view illustrating a sensor according to the first embodiment. Figure 1 is a cross-sectional view taken along line A1-A2 in Figure 3. Figure 2(a) is a cross-sectional view taken along line B1-B2 in Figure 3. Figure 2(b) is a cross-sectional view taken along line B3-B4 in Figure 3. Figure 2(c) is a cross-sectional view taken along line B5-B6 in Figure 3.
[0009] As shown in Figures 1 and 3, the sensor 110 according to this embodiment includes an element section 10E. The element section 10E includes a first substrate 51s and a first element 10A. The first substrate 51s may include, for example, a silicon substrate. The first substrate 51s may include electronic circuits such as transistors.
[0010] The first element 10A includes a first fixing member 21F fixed to the first substrate 51s, a first connecting member 21C supported by the first fixing member, and a first film portion 11F supported by the first connecting member 21C.
[0011] The first direction D1 from the first base 51s to the first fixing member 21F is defined as the Z-axis direction. One direction perpendicular to the Z-axis direction is defined as the X-axis direction. The direction perpendicular to both the Z-axis direction and the X-axis direction is defined as the Y-axis direction.
[0012] For example, the first base 51s includes a first surface 51F. The first surface 51F is aligned with the XY plane. The first fixing member 21F is fixed to the first surface 51F.
[0013] The second direction D2 from the first fixing member 21F to the first membrane portion 11F intersects with the first direction D1. The second direction D2 is, for example, the X-axis direction.
[0014] As shown in Figure 1, a first gap g1 is provided between the first substrate 51s and the first membrane portion 11F.
[0015] As shown in Figure 1, the first film portion 11F includes a first resistive layer 11a, a first conductive layer 11b, and a first conductive member 11c. The first conductive member 11c is provided between the first resistive layer 11a and the first conductive layer 11b.
[0016] The potential of the first conductive member 11c is fixed. The first conductive member 11c is set to, for example, the ground potential (GND potential).
[0017] The first electrical resistance R1 of the first resistive layer 11a changes depending on the state of the object being detected around the first element 10A.
[0018] As shown in FIG. 1, a control unit 70 may be provided in the sensor 110. The control unit 70 may be included in the sensor 110. The control unit 70 may be provided separately from the sensor 110. The control unit 70 can supply a first power to the first conductive layer 11b to detect the first electrical resistance R1. When the first power is supplied, the temperature of the first film portion 11F rises. The heat of the first film portion 11F propagates, for example, from the first film portion 11F to its surroundings. A part of the heat passes through the first gap g1 and propagates to the first substrate 51s. Another part of the heat propagates upward from the first film portion 11F.
[0019] For example, depending on the state of the detection target around the first element 10A, the heat propagation (heat dissipation) changes. The detection target is, for example, a gas. For example, the thermal conductivity of the gas around the first element 10A depends on the elements (and / or molecules) contained in the gas and its concentration. The heat dissipation property changes according to the state of the detection target (the type and concentration of the gas), and as a result, the first electrical resistance R1 of the first resistance layer 11a changes. By detecting the first electrical resistance R1, the state of the detection target (the gas and the change in the concentration of the gas) can be detected.
[0020] Thus, in the embodiment, in a state where the temperature of the first film portion 11F has risen due to the first power supplied to the first conductive layer 11b, the first electrical resistance R1 changes according to the state of the detection target.
[0021] The detection target exists in the first gap g1. The first electrical resistance R1 changes according to the state of the detection target between the first substrate 51s and the first film portion 11F.
[0022] In such a sensor 110, it has been found that the signal obtained from the first resistance layer 11a (the signal corresponding to the first electrical resistance R1) is likely to include noise. For example, due to the temperature rise, a large current is supplied to the first conductive layer 11b. It is considered that the noise contained in the large current causes noise in the signal obtained from the first resistance layer 11a.
[0023] In this embodiment, a first conductive member 11c is provided between the first resistive layer 11a and the first conductive layer 11b. The first conductive member 11c, whose potential is fixed, functions as a shield. This suppresses noise in the signal obtained from the first resistive layer 11a. As a result, the target can be detected with high accuracy. According to this embodiment, a sensor with improved characteristics can be provided.
[0024] In this embodiment, for example, the first conductive layer current flowing through the first conductive layer 11b during the supply of first power is large. This allows the first film portion 11F to be heated effectively. On the other hand, the first resistive layer current flowing through the first resistive layer 11a during the detection of the first electrical resistance R1 is relatively small. For example, the first conductive layer current is larger than the first resistive layer current.
[0025] Noise is more likely to occur when the current of the first conductive layer is greater than the current of the first resistive layer. In this embodiment, even in such a state where noise is likely to occur, the noise can be effectively suppressed by providing the first conductive member 11c.
[0026] For example, the current of the first conductive layer is at least twice the current of the first resistive layer. For example, the current of the first conductive layer may be at least five times the current of the first resistive layer.
[0027] The first conductive member 11c may be electrically connected to the first substrate 51s. The first substrate potential of the first substrate 51s may be substantially the same as the potential of the first conductive member 11c.
[0028] For example, as shown in Figure 1, in the first direction D1, the first resistive layer 11a may be provided between the first substrate 51s and the first conductive layer 11b. By providing the first resistive layer 11a between the first substrate 51s and the first conductive layer 11b, where the potential is fixed, noise can be further suppressed in the first resistive layer 11a.
[0029] In the embodiment, it is preferable that the electrical resistance of the first conductive layer 11b is low and the electrical resistance of the first resistive layer 11a is high. A low resistance in the conductive layer allows, for example, to reduce the heater voltage. A high resistance in the resistive layer allows, for example, to increase the sensitivity as a gas sensor.
[0030] For example, the first conductive layer 11b preferably contains at least one selected from the group consisting of Au, Al, Ti, TiN, and Pt. This allows for an effective increase in temperature.
[0031] The first resistive layer 11a preferably contains at least one selected from the group consisting of Au, Al, Ti, TiN, and Pt. This makes it easier to obtain stable characteristics.
[0032] As shown in Figures 3(a) to 3(c), a portion of the first conductive member 11c overlaps with the first conductive layer 11b and the first resistive layer 11a in the first direction D1. The other portion of the first conductive member 11c does not need to overlap with the first conductive layer 11b and the first resistive layer 11a in the first direction D1.
[0033] For example, in a plane intersecting the first direction D1 (e.g., the XY plane), at least a portion of the outer edge 11r of the first conductive member 11c lies outside the first conductive layer 11b and the first resistive layer 11a. For example, in the first film portion 11F, it is preferable that the area of the first conductive member 11c is larger than the area of the first conductive layer 11b and larger than the area of the first resistive layer 11a. A stable shielding effect can be obtained.
[0034] The large surface area of the first conductive member 11c suppresses temperature non-uniformity in the first film portion 11F, for example. High temperature uniformity is easily achieved.
[0035] As shown in Figure 2(b), the width of the first connecting member 21C in the third direction D3 is defined as the first connecting member width w21C. The third direction D3 intersects with the plane containing the first direction D1 and the second direction D2. The third direction D3 may be, for example, the Y-axis direction. As shown in Figure 2(a), the width of the first film portion 11F in the third direction D3 is defined as the first film portion width w11F. In this embodiment, the first connecting member width w21C is narrower than the first film portion width w11F. For example, heat dissipation through the first connecting member 21C can be suppressed. High sensitivity is easily obtained.
[0036] As shown in Figures 1 and 3, the first element 10A may further include a first other fixing member 21FA fixed to the first substrate 51s and a first other connecting member 21CA supported by the first other fixing member 21FA. The first other connecting member 21CA supports the first film portion 11F. In this example, the first film portion 11F is located between the first connecting member 21C and the first other connecting member 21CA. The first film portion 11F is supported more stably.
[0037] As shown in Figure 2(c), the width of the first connecting member 21CA in the third direction D3 is defined as the first connecting member width w21CA. The first connecting member width w21CA is narrower than the first film width w11F. For example, heat dissipation through the first connecting member 21C can be suppressed. High sensitivity is easily obtained.
[0038] As shown in Figures 1 and 2(a), the first film portion 11F may include a first insulating member 11i. The first insulating member 11i is provided around the first resistive layer 11a and the first conductive member 11c.
[0039] As shown in Figures 1, 2(b), and 2(c), for example, a portion of the first resistive layer 11a passes through the first connecting member 21C and the first other connecting member 21CA. For example, a portion of the first resistive layer 11a passes through the first connecting member 21C and the first other connecting member 21CA and is electrically connected to the control unit 70. For example, a portion of the first conductive layer 11b extends along the first connecting member 21C and the first other connecting member 21CA. A portion of the first conductive layer 11b extends along the first connecting member 21C and the first other connecting member 21CA and is electrically connected to the control unit 70.
[0040] The control unit 70 can detect the first electrical resistance R1 by supplying first power to the first conductive layer 11b, for example, via the first connecting member 21C and the first other connecting member 21CA.
[0041] The first conductive member 11c passes through, for example, the first connecting member 21C. The first conductive member 11c does not need to pass through the first other connecting member 21CA.
[0042] Figure 4 is a schematic cross-sectional view illustrating a part of the sensor according to the first embodiment. As shown in Figure 4, in the sensor 111 according to this embodiment, the element section 10E includes a second base 52s and a second element 10B, in addition to the first base 51s and the first element 10A (omitted in Figure 4) described with respect to Figure 1. In sensor 111, the configuration of the first base 51s and the first element 10A may be the same as their configuration in sensor 110.
[0043] The second element 10B includes a second fixing member 22F fixed to the second substrate 52s, a second connecting member 22C supported by the second fixing member 22F, and a second film portion 12F supported by the second connecting member 22C. The second substrate 52s may be continuous with the first substrate 51s. The boundary between the second substrate 52s and the first substrate 51s may be clear or unclear. The second fixing member 22F is fixed to the second surface 52F of the second substrate 52s.
[0044] A second gap g2 is provided between the second substrate 52s and the second film portion 12F. The second film portion 12F includes a second resistive layer 12a. The control unit 70 can output a value corresponding to the difference between the second electrical resistance R2 of the second resistive layer 12a and the first electrical resistance R1 (see Figure 1). The control unit 70 includes, for example, a differential amplifier.
[0045] The second element 10B is, for example, a reference element. For example, the effects of fluctuations in ambient temperature are suppressed. Higher accuracy detection is possible.
[0046] In this example, the second film portion 12F includes a second conductive layer 12b. Power does not need to be supplied to the second conductive layer 12b. The second conductive layer 12b does not need to be used for detection. The second conductive layer 12b functions, for example, as a dummy conductive layer.
[0047] In this example, the second film portion 12F includes a second conductive member 12c. The second conductive member 12c is provided, for example, between the second resistive layer 12a and the second conductive layer 12b. The shielding effect of the second conductive member 12c allows for further suppression of noise in the signal obtained from the second resistive layer 12a.
[0048] In this embodiment, the second conductive layer 12b and the second conductive member 12c may be omitted. Alternatively, the configuration of the second element 10B may be substantially the same as that of the first element 10A. In the first element 10A and the second element 10B, the heat capacity and other properties become substantially the same, enabling detection with higher accuracy.
[0049] In the sensor 111, the second element 10B may further include a second other fixing member 22FA fixed to the second base 52s and a second other connecting member 22CA supported by the second other fixing member 22FA. The second other connecting member 22CA supports the second film portion 12F. For example, the second film portion 12F is located between the second connecting member 22C and the second other connecting member 22CA. The second film portion 12F is supported more stably. The second film portion 12F may include a second insulating member 12i.
[0050] (Second Embodiment) The second embodiment relates to a sensor system. As shown in Figure 1, the sensor system 210 according to the embodiment (see Figure 1) includes a sensor 110 and a communication unit 75 according to the embodiment. The communication unit 75 is capable of transmitting a signal corresponding to a change in the first electrical resistance R1. The sensor system 211 according to the embodiment (see Figure 4) includes a sensor 111 and a communication unit 75 according to the embodiment. The communication unit 75 is capable of transmitting a signal corresponding to a change in the first electrical resistance R1. According to the embodiment, a low-noise sensor signal can be acquired from a remote location.
[0051] The communication unit 75 can supply signals to the outside, for example, by at least one of wired and wireless methods. The communication unit 75 may also be able to acquire control signals from the outside. The control unit 70 may be controlled by control signals from the outside.
[0052] The embodiment may include the following configuration (e.g., proposed technical details). (Composition 1) The device comprises a first substrate and an element section including a first element, The first element is, A first fixing member fixed to the first base, A first connecting member supported by the first fixing member, The first membrane portion supported by the first connecting member, Includes, The second direction from the first fixing member to the first film portion intersects with the first direction from the first substrate to the first fixing member. A first gap is provided between the first substrate and the first membrane portion. The first film portion includes a first resistive layer, a first conductive layer, and a first conductive member provided between the first resistive layer and the first conductive layer. The potential of the first conductive member is fixed. The first electrical resistance of the first resistive layer changes depending on the state of the object to be detected around the first element, in this sensor.
[0053] (Configuration 2) The sensor according to configuration 1, wherein, when the temperature of the first film portion rises due to the power supplied to the first conductive layer, the first electrical resistance changes depending on the state of the object to be detected.
[0054] (Composition 3) The sensor according to configuration 1 or 2, wherein the first electrical resistance changes depending on the state of the object to be detected between the first substrate and the first film portion.
[0055] (Composition 4) In the first direction, the first resistive layer is provided between the first substrate and the first conductive layer, as described in any one of configurations 1 to 3.
[0056] (Composition 5) The first conductive member is electrically connected to the first substrate, and the sensor is as described in configuration 4.
[0057] (Composition 6) The sensor according to configuration 4, wherein the first substrate potential of the first substrate is substantially the same as the potential of the first conductive member.
[0058] (Composition 7) The sensor according to any one of configurations 1 to 6, wherein the conductivity of the first conductive layer is higher than the conductivity of the first resistive layer.
[0059] (Composition 8) The first conductive layer comprises at least one selected from the group consisting of Au, Al, Ti, TiN, and Pt. The sensor according to any one of configurations 1 to 7, wherein the first resistive layer includes at least one selected from the group consisting of Au, Al, Ti, TiN, and Pt.
[0060] (Composition 9) A portion of the first conductive member overlaps with the first conductive layer and the first resistive layer in the first direction. The sensor according to any one of configurations 1 to 8, wherein the other part of the first conductive member does not overlap with the first conductive layer and the first resistive layer in the first direction.
[0061] (Composition 10) The sensor according to any one of configurations 1 to 8, wherein, in a plane intersecting the first direction, at least a portion of the outer edge of the first conductive member is outside the first conductive layer and the first resistive layer.
[0062] (Composition 11) The sensor according to any one of configurations 1 to 10, wherein the width of the first connecting member in a third direction intersecting a plane including the first and second directions is narrower than the width of the first film portion in the third direction.
[0063] (Composition 12) The first element is, A first other fixing member fixed to the first base, The first connecting member supported by the first other fixing member, It further includes, The first connecting member is a sensor according to any one of configurations 1 to 11, which supports the first membrane portion.
[0064] (Composition 13) It further includes a control unit, A portion of the first resistive layer is electrically connected to the control unit by passing through the first connecting member and the first other connecting member. A portion of the first conductive layer extends along the first connecting member and the first other connecting member and is electrically connected to the control unit. The control unit supplies first power to the first conductive layer and the sensor according to configuration 12 is capable of detecting the first electrical resistance.
[0065] (Composition 14) The sensor according to configuration 13, wherein the first conductive member passes through the first connecting member but does not pass through the first other connecting member.
[0066] (Composition 15) It further includes a control unit, A portion of the first resistive layer is electrically connected to the control unit by passing through the first connecting member. A portion of the first conductive layer extends along the first connecting member and is electrically connected to the control unit. The control unit supplies first power to the first conductive layer and is capable of detecting the first electrical resistance, as described in any one of configurations 1 to 11.
[0067] (Composition 16) It further includes a control unit, The control unit supplies first power to the first conductive layer and is capable of detecting the first electrical resistance, as described in configuration 1.
[0068] (Composition 17) The sensor according to configuration 16, wherein the first conductive layer current flowing through the first conductive layer during the supply of the first power is greater than the first resistive layer current flowing through the first resistive layer during the detection of the first electrical resistance.
[0069] (Composition 18) The sensor according to configuration 17, wherein the current of the first conductive layer is twice or more the current of the first resistive layer.
[0070] (Composition 19) The element portion further includes a second substrate and a second element, The second element is, A second fixing member fixed to the second base, A second connecting member supported by the second fixing member, The second membrane portion supported by the second connecting member, Includes, A second gap is provided between the second substrate and the second membrane portion. The second film portion includes a second resistive layer, The control unit is capable of outputting a value corresponding to the difference between the second electrical resistance of the second resistive layer and the first electrical resistance, as described in any one of configurations 16 to 18.
[0071] (Composition 20) The sensor described in Configuration 1, A communication unit capable of transmitting a signal corresponding to the change in the first electrical resistance, A sensor system equipped with [unspecified features].
[0072] According to the embodiment, a sensor and sensor system capable of improving characteristics can be provided.
[0073] The embodiments of the present invention have been described above with reference to specific examples. However, the present invention is not limited to these specific examples. For example, the specific configuration of each element included in the sensor and sensor system, such as the substrate, element part, fixing member, connecting member, membrane part, and control unit, is included within the scope of the present invention as long as those skilled in the art can appropriately select from the known range to implement the present invention and obtain similar effects.
[0074] Combinations of two or more elements from any of the specific examples, to the extent technically feasible, are also included within the scope of the present invention, insofar as they encompass the gist of the invention.
[0075] Furthermore, all sensors and sensor systems that a person skilled in the art can design and implement based on the sensors and sensor systems described above as embodiments of the present invention, insofar as they encompass the gist of the present invention, also fall within the scope of the present invention.
[0076] Furthermore, within the scope of the concept of the present invention, a person skilled in the art could conceive of various modifications and alterations, and it is understood that such modifications and alterations also fall within the scope of the present invention.
[0077] While several embodiments of the present invention have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These novel embodiments can be carried out in a variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents. [Explanation of Symbols]
[0078] 10A, 10B: First and second elements, 10E: Element section, 11F, 12F: First and second film sections, 11a, 12a: First and second resistive layers, 11b, 12b: First and second conductive layers, 11c, 12c: First and second conductive members, 11i, 12i: First and second insulating members, 11r: Outer edge, 21C, 22C: First and second connecting members, 21CA, 22CA: First and second other connecting members, 21F, 22F: First and second fixing members, 21FA, 22FA: First and second other fixing members, 51F, 52F: First and second surfaces, 51s, 52s: First and second substrates, 70: Control section, 75: Communication section, 110, 111: Sensors, 210, 211: Sensor system, D1~D3: 1st~3rd directions, R1, R2: 1st and 2nd electrical resistances, g1, g2: 1st and 2nd gaps, w11F: 1st membrane width, w21C: 1st connecting member width, w21CA: 1st other connecting member width
Claims
1. The device comprises a first substrate and a first element, The first element is, A first fixing member fixed to the first base, The first connecting member supported by the first fixing member, The first membrane portion supported by the first connecting member, Includes, The second direction from the first fixing member to the first film portion intersects with the first direction from the first substrate to the first fixing member. A first gap is provided between the first substrate and the first membrane portion. The first film portion includes a first resistive layer, a first conductive layer, and a first conductive member provided between the first resistive layer and the first conductive layer. The potential of the first conductive member is fixed. The first electrical resistance of the first resistive layer changes depending on the state of the object being detected between the first substrate and the first film portion. In the first direction, the first resistive layer is provided between the first substrate and the first conductive layer. A sensor in which the first substrate potential of the first substrate is substantially the same as the potential of the first conductive member.
2. The sensor according to claim 1, wherein, when the temperature of the first film portion rises due to the power supplied to the first conductive layer, the first electrical resistance changes depending on the state of the object to be detected.
3. The sensor according to claim 1 or 2, wherein the width of the first connecting member in a third direction intersecting a plane including the first and second directions is narrower than the width of the first membrane portion in the third direction.
4. The first element is, A first other fixing member fixed to the first base, The first other connecting member supported by the first other fixing member, It further includes, The sensor according to claim 1, wherein the first connecting member supports the first membrane portion.
5. It further includes a control unit, A portion of the first resistive layer is electrically connected to the control unit by passing through the first connecting member and the first other connecting member. A portion of the first conductive layer extends along the first connecting member and the first other connecting member and is electrically connected to the control unit. The sensor according to claim 4, wherein the control unit can supply first power to the first conductive layer to detect the first electrical resistance.
6. It further includes a control unit, The sensor according to claim 1, wherein the control unit can supply first power to the first conductive layer to detect the first electrical resistance.
7. The element portion further includes a second substrate and a second element, The second element is, A second fixing member fixed to the second base, A second connecting member supported by the second fixing member, The second membrane portion supported by the second connecting member, Includes, A second gap is provided between the second substrate and the second membrane portion. The second film portion includes a second resistive layer, The sensor according to claim 6, wherein the control unit is capable of outputting a value corresponding to the difference between the second electrical resistance of the second resistive layer and the first electrical resistance.
8. The sensor according to claim 1, A communication unit capable of transmitting a signal corresponding to the change in the first electrical resistance, A sensor system equipped with [unspecified features].