Sensor element and gas sensor

Abstract

The invention discloses a sensor element and a gas sensor. The sensor element comprises a substrate and a film arranged on the substrate, the substrate is provided with a cavity and an opening communicated with the cavity; the film is supported on the opening and partially covers the cavity; the film comprises a first heating resistor and a second heating resistor which are both composed of zigzag lines, the first heating resistor is arranged on the side, close to the cavity, of the film, and the second heating resistor is arranged on the side, away from the cavity, of the film; the end linear part of the first heating resistor piece and the end linear part of the second heating resistor piece are at least partially overlapped, so that the thermal stress caused by the first heating resistor piece and the thermal stress caused by the second heating resistor piece are mutually counteracted. According to the sensor element and the gas sensor, a double-layer structure in which the first heating resistor piece and the second heating resistor piece are matched with each other is designed, so that thermal stress generated by heating is counteracted, the deformation phenomenon of a membrane structure is avoided, and the stability of the gas sensor is guaranteed.

Description

Technical Field

[0001] The present invention relates to the technical field of gas sensors, and in particular to a sensor element and a gas sensor. Background Art

[0002] A gas sensor is a device that can sense a specific gas and its concentration in the environment. It converts information about the gas type and concentration into an electrical signal, enabling detection, monitoring, analysis, and alarms. A gas sensor is equipped with a heating element and a membrane structure. The heating element improves the sensor's response to gas and increases detection sensitivity. The membrane structure inhibits heat transfer to the outside, ensuring that only the inner part of the membrane is effectively heated, reducing the energy required for overheating.

[0003] However, over extended use, the heat generated within the gas sensor can generate thermal stress, which in turn can cause the membrane structure to deform. This deformation can alter the sensor's resistance characteristics, affecting detection sensitivity. Therefore, ensuring the stable operation of gas sensors and preventing membrane deformation has become a pressing technical challenge for those skilled in the art. Summary of the Invention

[0004] The present invention provides a sensor element and a gas sensor, which are designed with a double-layer structure consisting of a first heating resistor and a second heating resistor that cooperate with each other, so that the thermal stresses generated by heating can be offset by each other, avoiding deformation of the membrane structure, thereby ensuring the stability of the gas sensor.

[0005] In order to solve the above technical problems, an embodiment of the present invention provides a sensor element, comprising a substrate and a thin film provided on the substrate;

[0006] The base has a cavity and an opening communicating with the cavity;

[0007] The film is supported on the opening and partially covers the cavity;

[0008] The film includes a first heating resistor and a second heating resistor, both of which are formed by zigzag lines. The first heating resistor is arranged on a side of the film close to the cavity, and the second heating resistor is arranged on a side of the film away from the cavity.

[0009] The end linear portion of the first heating resistor and the end linear portion of the second heating resistor at least partially overlap, so that thermal stress caused by the first heating resistor and thermal stress caused by the second heating resistor offset each other.

[0010] As one preferred solution, the film further comprises a thermistor electrode and a thermistor material;

[0011] The thermistor electrode and the first heating resistor or the second heating resistor are located in the same plane, and the thermistor material at least partially covers the thermistor electrode.

[0012] As one preferred solution, the film further comprises a thermistor electrode and a thermistor material;

[0013] The first heating resistor is arranged on a side of the film close to the cavity;

[0014] The second heating resistor is arranged on a side of the film away from the first heating resistor;

[0015] The thermistor electrode is arranged on a side of the film away from the second heating resistor, and the thermistor material at least partially covers the thermistor electrode.

[0016] As one preferred solution, the film further includes a first thermistor electrode, a first thermistor material, and a second thermistor electrode;

[0017] The first thermistor electrode and the first heating resistor are located in the same plane, and the first thermistor material at least partially covers the first thermistor electrode; the second thermistor electrode and the second heating resistor are located in the same plane.

[0018] As a preferred solution, the film further includes a second thermistor material, and the second thermistor material at least partially covers the second thermistor electrode.

[0019] As one preferred solution, the thermistor electrode is provided in a nonlinear portion of the first heating resistor element or the second heating resistor element.

[0020] As one preferred solution, the bending direction of the nonlinear portion of the first heating resistor is rotated by 180° relative to the bending direction of the nonlinear portion of the second heating resistor.

[0021] As a preferred solution, the first heating resistor and the second heating resistor are connected in parallel in the circuit.

[0022] As one preferred solution, a voltage amplifier is further provided in the circuit to adjust the voltage applied to the first heating resistor and the second heating resistor.

[0023] As a preferred solution, the film further includes an insulator provided between the first heating resistor and the second heating resistor, and the first heating resistor and the second heating resistor are isolated from each other by the insulator.

[0024] As one preferred solution, the film further includes a first insulator;

[0025] The thermistor electrode and the second heating resistor are located in the same plane, and the thermistor material at least partially covers the thermistor electrode and the second heating resistor;

[0026] The first insulator is disposed under the second heating resistor. The first insulator partially covers the first heating resistor. The first heating resistor is disposed on a side of the first insulator away from the second heating resistor.

[0027] As one preferred solution, the sensor element further includes a second insulator;

[0028] The second insulator is provided on a lower layer of the first heating resistor.

[0029] As one preferred solution, the film has a dummy pattern, and the dummy pattern is used to receive heat flow and expand to eliminate the deformation caused by the thermistor electrode.

[0030] As one preferred solution, the sensor element is further provided with a plurality of thermal through holes, and the first heating resistor and the second heating resistor are thermally coupled via the thermal through holes.

[0031] As one preferred solution, when the sensor is working, the voltage applied to the first heating resistor is a first voltage, the voltage applied to the second heating resistor is a second voltage, and the first voltage is greater than or equal to the second voltage.

[0032] Another embodiment of the present invention provides a gas sensor including the sensor element described above.

[0033] Compared with the prior art, the embodiments of the present invention have the following advantages:

[0034] The first heating resistor and the second heating resistor cooperate with each other. The thermal stress in the film thickness direction caused by the heat generated by the first heating resistor and the thermal stress in the film thickness direction caused by the heat generated by the second heating resistor are in opposite directions, which can offset each other's stresses and make the thermal stresses in the film thickness direction offset each other. The thermal stress in the film thickness direction can be significantly reduced, effectively avoiding deformation of the membrane structure, making the resistance characteristics in the gas sensor stable and not easy to change, thereby ensuring the stable performance of the gas sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 is a schematic structural diagram of a first embodiment of the present invention;

[0036] Figure 2 is a side view of the first embodiment of the present invention on the xz plane;

[0037] Figure 3 This invention Figure 2 A top view of plane A of the first embodiment;

[0038] Figure 4 This invention Figure 2 A schematic diagram of the first embodiment showing plane B from the top;

[0039] Figure 5 1 is a schematic diagram of a circuit for driving a first heating resistor and a second heating resistor according to the present invention;

[0040] Figure 6 is a simulation result when a voltage is applied to the first heating resistor;

[0041] Figure 7 is a simulation result when a voltage is applied to the second heating resistor;

[0042] Figure 8 is a simulation result of the present invention when voltage is applied to the first heating resistor and the second heating resistor of the first embodiment;

[0043] Figure 9 This invention Figures 6 to 8 Schematic diagram for comparison of simulation results;

[0044] Figure 10 is a schematic structural diagram of a second embodiment of the present invention;

[0045] Figure 11 is a side view (-y axis direction) of the second embodiment of the present invention;

[0046] Figure 12 This invention Figure 11 Top view of the A plane (+z axis direction);

[0047] Figure 13 This invention Figure 11 Top view of the middle B plane (+z axis direction);

[0048] Figure 14 is a schematic structural diagram of a third embodiment of the present invention;

[0049] Figure 15 is a side view (along the -y axis direction) of the third embodiment of the present invention;

[0050] Figure 16 This invention Figure 15 Top view of the A plane (+z axis direction);

[0051] Figure 17 This invention Figure 15 View of the middle B plane from the (+z) direction;

[0052] Figure 18 is a schematic diagram of two thermistor electrodes according to a third embodiment of the present invention;

[0053] Figure 19 is a schematic structural diagram of a fourth embodiment of the present invention;

[0054] Figure 20 is a side view (along the -y axis direction) of the fourth embodiment of the present invention;

[0055] Figure 21 is a schematic diagram of plane A shown at the top of a fourth embodiment of the present invention;

[0056] Figure 22 is a schematic diagram showing plane B from the top of the fourth embodiment of the present invention;

[0057] Figure 23 is a schematic structural diagram of a fifth embodiment of the present invention;

[0058] Figure 24 The fifth embodiment of the present invention is different from the first embodiment Figure 4 corresponding floor plan;

[0059] Figure 25 is a schematic diagram of a circuit for driving a first heating resistor and a second heating resistor according to the present invention;

[0060] Figure 26 It is a schematic diagram of a circuit with a voltage amplifier of the present invention;

[0061] Figure 27 This is the first shape and structure design of each component of the present invention;

[0062] Figure 28 This is the second shape and structure design of the various components of the present invention;

[0063] Figure 29 This is the third shape and structure design of the various components of the present invention;

[0064] Figure 30 This is the fourth shape and structure design of the various components of the present invention;

[0065] Figure 31 This is the fifth shape and structure design of the various components of the present invention;

[0066] Figure 32 This is the sixth shape and structure design of the various components of the present invention;

[0067] Figure 33 1 is a schematic plan view of a dummy pattern having a first structure according to the present invention;

[0068] Figure 34 1 is a schematic plan view of a dummy pattern having a second structure according to the present invention;

[0069] Figure 35 1 is a schematic plan view of a dummy pattern having a third structure according to the present invention;

[0070] Figure 36 1 is a schematic plan view of a dummy pattern having a fourth structure according to the present invention;

[0071] Figure 37 1 is a schematic plan view of a dummy pattern having a fifth structure according to the present invention;

[0072] Figure 38 is a related curve diagram of the present invention;

[0073] Reference numerals:

[0074] Among them, 101, sensor element; 102, substrate; 103, cavity; 104, film; 105, first heating resistor; 105a, one end of the first heating resistor; 105b, one end of the first heating resistor; 106, second heating resistor; 106a, one end of the second heating resistor; 106b, one end of the second heating resistor; 107, thermistor electrode; 108, thermistor material; 109a, bonding wire; 109b, bonding wire; 109c, bonding wire; 109d, bonding wire; 110, insulator; 110a, first Insulator; 110b, second insulator; 111, contact surface between the first heating resistor element and the pad; 112, gap; 113a, pad; 113d, pad; 114, dummy pattern (pseudo-pattern); 115, second thermistor electrode; 116, thermal via; 201, voltage source; 202, resistance of the first heating resistor element; 203, resistance of the second heating resistor element; 204, series circuit; 205, resistance of the fourth heating electrode; 206, resistance of the fifth heating electrode; 207, resistance of the thermistor electrode; 208, resistance of the second thermistor electrode. DETAILED DESCRIPTION

[0075] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. The purpose of providing these embodiments is to make the disclosure of the present invention more thorough and comprehensive. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0076] In the description of this application, the terms "first," "second," "third," etc. are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Therefore, a feature specified as "first," "second," "third," etc. may explicitly or implicitly include one or more of the features. In the description of this application, unless otherwise specified, "plurality" means two or more.

[0077] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be a communication between the two components. The terms "vertical", "horizontal", "left", "right", "up", "down" and similar expressions used herein are for illustrative purposes only, and do not indicate or imply that the device or component referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0078] In the description of this application, it should be noted that, unless otherwise defined, all technical and scientific terms used in this application have the same meanings as those commonly understood by those skilled in the art. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood by those skilled in the art in specific circumstances.

[0079] First embodiment:

[0080] It should be noted in advance that for the heating components / devices in gas sensors, a planar pattern coil (such as a winding or spiral coil) is generally designed. The thickness of the planar coil is relatively thin, which can effectively heat the planar membrane structure. For the membrane structure that realizes heating, a thicker membrane structure will result in a larger heat capacity, and heating requires more energy input, resulting in uneven heating within the membrane. Therefore, the membrane structure needs to be relatively thin. However. When the membrane structure is very thin, the heat generated by heating will cause thermal stress, causing the membrane structure to deform, and the long-term use of the gas sensor will also accelerate this deformation process.

[0081] In heated gas sensors, the thermistor is typically mounted on the upper or lower surface of the diaphragm, which is in contact with the outside air. Diaphragm deformation can cause the thermistor structure to deform, resulting in changes in resistance characteristics. Therefore, to maintain long-term stable gas sensor characteristics, it is essential to ensure that the diaphragm does not deform.

[0082] The first embodiment of the present invention provides a sensor element 101. For details, see Figure 1 , Figure 1 It is a schematic structural diagram of a first embodiment of the present invention, which includes a substrate 102 and a film 104 provided on the substrate 102 , wherein the film 104 includes a first heating resistor 105 and a second heating resistor 106 .

[0083] The substrate 102 is also called the base material. The base material needs to have appropriate mechanical strength and can be a material suitable for micro-processing such as etching. There are no special restrictions. For example, it can be a silicon single crystal substrate, a sapphire single crystal substrate, a ceramic substrate, a quartz substrate, a glass substrate, etc., which are not specifically limited here.

[0084] In the embodiment of the present invention, the substrate 102 is a rectangular structure with a cavity 103 in the center. The surface of the substrate 102 has an opening connected to the cavity 103. The film 104 is arranged on the upper part of the substrate 102. Due to the presence of the cavity 103, the central part of the film 104 does not directly contact the substrate 102. The above opening is partially covered with the film 104, such as Figure 1 As shown, the central part of the opening is provided with a film 104, which is supported on the opening by four oblique arms, that is, the opening portion also has a gap 112, as shown in FIG. Figure 1 Four trapezoidal-shaped gaps are shown, with which the membrane 104 is supported at several points around the openings and fixed to the substrate 102.

[0085] The first heating resistor 105 and the second heating resistor 106 are both composed of a zigzag line, including a linear straight line portion and a nonlinear serpentine portion. For example, the input / output line of the zigzag line (serpentine) of the first heating resistor 105 in the lower layer is located below the input / output line of the zigzag line (serpentine) of the second heating resistor 106 in the upper layer. The linear portion of the serpentine starting end and end of the first heating resistor 105 and the linear portion of the serpentine starting end and end of the second heating resistor 106 at least partially overlap. Preferably, the first heating resistor 105 and the second heating resistor 106 are isolated by an insulator 110 to avoid electrical contact. In addition, the substrate 102 can be made of a conductive material by a MEMS process, such as a well-known silicon substrate. In this case, the substrate 102 and the first heating resistor 105 are isolated by the insulator 110 so that they do not make electrical contact.

[0086] In this embodiment, the first heating resistor 105 is located below the film 104. The second heating resistor 106 is located above the film 104. Figure 2 As shown, Figure 2 The first heating resistor 105 is in electrical contact with the pad 113a via the contact surface 111 between the first heating resistor and the pad, and the bonding wire 109a is connected to the pad 113a in contact with the first heating resistor.

[0087] Similarly, a pad-shaped portion is also provided at both ends of the second heating resistor 106, and the bonding wire 109b is connected to the pad-shaped portion. Although the ends of the bonding wires 109a and 109b are omitted in the figure, Figure 5 As shown, these ends are connected to a circuit for supplying power to the first heating resistor 105 and the second heating resistor 106 .

[0088] As described above, the film 104 contacts the substrate 102 via the cavity 103 or the gap 112 to reduce the heat capacity of the film 104 and simultaneously reduce heat conduction between the film 104 and the substrate 102. The reduction in the heat capacity and heat conduction of the film 104 enables the film 104 to be heated efficiently and quickly by Joule heat generated by applying a voltage to the first heating resistor 105 and the second heating resistor 106; furthermore, when the voltage of the first heating resistor 105 and the second heating resistor 106 becomes zero (i.e., turned off), the temperature drops even faster.

[0089] The above-mentioned sensor element can constitute a compact gas sensor heating device. However, in order to constitute a gas sensor, it is necessary to provide a thermistor electrode 107 and a thermistor material 108 on the film 104 .

[0090] The thermistor electrode 107 is a pattern made of a conductor such as copper, silver, gold or platinum. The thermistor electrode 107 is located on the same plane as the first heating resistor 105 or the second heating resistor 106. In the above embodiment, the thermistor electrode 107 and the second heating resistor 106 are arranged on the same plane. Figure 1 and Figure 4 As shown ( Figure 4 Shown as the present invention Figure 2 Schematic diagram of the first embodiment shown in plane B from the top, in which the first heating resistor and the bonding wire connected to the first heating resistor are omitted to make the structure of the top surface easier to understand. Preferably, the thermistor electrode 107 is arranged in the groove of the nonlinear portion (meandering portion) of the second heating resistor 106. By arranging the thermistor electrode 107 in this manner, the heat transfer efficiency can be improved, and the Joule heat generated by the second heating resistor 106 can be obtained more effectively.

[0091] like Figure 1 and Figure 4 As shown, the thermistor material 108 is disposed in contact with the thermistor electrode 107 , and the thermistor material 108 at least partially covers the thermistor electrode 107 .

[0092] Thermistor material 108 is a material whose resistance changes with temperature. When film 104 is heated by first heating resistor 105 or second heating resistor 106, the temperature rises, causing the resistance of thermistor material 108 to change. Because thermistor material 108 is in contact with thermistor electrode 107, the change in resistance of thermistor material 108 also changes the resistance of thermistor electrode 107.

[0093] exist Figure 4 In the embodiment, thermistor electrode 107 preferably consists of two patterns 107a and 107b. To achieve a resistance value between thermistors of the order of kΩ or higher, two or more patterns may be used and further arranged so that a certain gap exists between their surfaces. Furthermore, if the resistance is less than 100 ohms, a single pattern may be arranged without a gap.

[0094] Generally speaking, in gas-heating gas sensors, heating the gas via a heater electrode improves accuracy. In thermal conductivity gas sensors, gas concentration is determined based on the temperature change during gas heating. Concentration is measured using the change in thermal conductivity of the gas during heating. When the gas is heated by the heater electrode, the temperature change is detected by a thermistor to determine gas concentration. Thermistors are commonly used for this type of temperature detection.

[0095] like Figure 4As shown, the thermistor electrode 107 and the second heating resistor 106 are arranged on the same plane. As mentioned above, heating can be performed by the second heating resistor 106 or by Figure 3 The first heating resistor 105 on the lower plane is heated by heat conduction ( Figure 3 Shown as the present invention Figure 2 Therefore, a method that can effectively heat the thermistor electrode 107 can be selected according to actual needs.

[0096] In addition, the thermistor material 108 can be set to cover the thermistor electrode 107 only, or can be set to cover the second heating resistor 106 together for ease of manufacture. Figure 1 and Figure 4 As shown, the entire film 104 is covered, and those skilled in the art can make a selection based on actual process requirements.

[0097] Figures 1 to 4 The bonding wires 109a, 109b and 109c are wires made of materials such as gold, aluminum and copper, and are connected to the pads 113a connected to the first heating resistor 105, the second heating resistor 106 and the pads at both ends of the thermistor electrode 107 using heat, ultrasound and pressure.

[0098] Furthermore, the other ends of the bonding wires 109a and 109b are connected to a circuit for applying a heating voltage, and the other end of the bonding wire 109c is connected to a circuit for detecting a change in resistance of the thermistor.

[0099] Figure 5 The circuit example of driving the first heating resistor 105 and the second heating resistor 106 is shown. The figure shows a resistor 202 and a resistor 203 connected in parallel with the voltage source 201. The resistor 202 is equivalent to the resistance of the first heating resistor 105 and the bonding wire 109a. In other words, it shows Figures 1 to 3 How is the end of the bonding wire 109a not connected to the pad 113a connected to Figure 5 On the other hand, the resistor 203 is equivalent to the resistance of the second heating resistor 106 and the bonding wire 109b. In other words, it shows Figure 1 、 Figure 2 and Figure 4 How is the other end of the bonding wire 109b in contact with the pads at both ends of the second heating resistor 106 connected to the Figure 5 in the circuit.

[0100] That is, in Figure 5In the embodiment, the resistance 202 of the first heating resistor 105 is shown as RH1, and the resistance 203 of the second heating resistor 106 is shown as RH2. In the first embodiment, RH1 is greater than RH2, which is determined by the shape and size. Figure 3 and Figure 4 As shown, the pattern length of the first heating resistor 105 is longer than the pattern length of the second heating resistor 106 .

[0101] exist Figure 5 In the circuit, the resistor 202 and the resistor 203 are connected in parallel and connected to the voltage source 201. Therefore, when the voltage source 201 generates a voltage, the voltage is applied to the resistor 202 and the resistor 203 at the same time.

[0102] In other words, the voltage generated by the voltage source 201 is applied to the first heating resistor 105 and the second heating resistor 106 at the same time, which causes the first heating resistor 105 and the second heating resistor 106 to consume power and generate heat.

[0103] because Figure 5 The circuit in FIG. 1 does not include either a capacitor or an inductor, so the time for the first heating resistor 105 and the second heating resistor 106 to generate Joule heat is the same. Figure 5 In the figure, the voltage source 201 is shown as a simple pulse source symbol, but the voltage level can vary according to time and can also be a sine wave, a triangle wave or a PWM wave. It is important that the driving time of the first heating resistor 105 and the second heating resistor 106 must be the same.

[0104] In order to illustrate the derivation process of the present invention in detail, simulation experiments are separately described below.

[0105] Figure 6 The simulation results when a voltage is applied to the first heating resistor are shown. Figure 6 The simulation results are shown when the thermistor 107 and the first heating resistor 105 are set on the film 104. As mentioned above, the first heating resistor 105 is set on the lower surface of the film 104, and the thermistor electrode 107 is set on the upper surface of the film 104. At this time, when the sensor element is working, it will produce a deformation phenomenon (bending downward) as shown on the right.

[0106] Figure 7 The simulation results when a voltage is applied to the second heating resistor are shown. Figure 7The simulation results are shown when thermistor 107 and second heating resistor 106 are provided on film 104. As described above, in this case, second heating resistor 106 and thermistor 107 are provided on the upper surface of film 104. In this case, the sensor element deforms (bends upward) during operation, as shown on the right.

[0107] As can be seen from the above, since the bending directions are opposite, the upper and lower deformations can be offset by a reasonable design of the double-layer heating resistor. Figure 8 The figure shows the simulation results when voltage is applied to the first and second heating resistors of the first embodiment. Specifically, the first heating resistor 105 is positioned on the lower surface of the membrane 104, while the second heating resistor 106 and thermistor electrode 107 are positioned on the upper surface of the membrane 104. The deformation in this case is shown schematically on the right, with virtually no noticeable bending.

[0108] The actual analysis process was based on the finite element method, employing coupled electrical, thermal, and thermal stress analysis. First, an electrical analysis was performed. This analysis calculated the current and resistance of each component based on the voltage applied to the pad, the resistivity, and the geometry parameters of the heating resistor, thermistor electrode, thermistor material, the insulator, and the substrate. Next, a thermal analysis was performed. Joule heating was calculated based on the current and resistance values ​​obtained from the electrical analysis, and the temperature of each component was calculated based on Joule heating and thermal conductivity, heat transfer coefficient, thermal emissivity, and specific heat. During this second electrical analysis, the change in resistivity caused by temperature increase was taken into account, especially for metal components, as resistivity changes significantly with temperature. The current and resistance of each component were calculated based on the updated resistivity due to the temperature increase and the updated geometry parameters. In this way, the resistivity, current, Joule heating, and temperature of each component were calculated, and the electrical and thermal analyses converged repeatedly. Finally, a thermal stress analysis was performed. Thermal stress is calculated based on temperature and the linear expansion coefficient, Young's modulus, and Poisson's ratio of each component, and the strain of each component is also calculated.

[0109] It should be noted that Figures 6 to 8 In the simulation diagram shown, the effect of bending deformation is magnified and exaggerated so that the deformation can be easily seen in the diagram, which helps to understand it.

[0110] Furthermore, since an overly complex simulation model would increase the amount of memory required for analysis and make analysis more difficult, the pad 113a was omitted from the simulation model. For the same reason, the thermistor material 108 was also omitted from the simulation. Figure 6 6(a) and 6(b) show views of the film 104 as viewed from the top surface. Figure 6(a) shows the pattern on the upper surface of the film 104, that is, the figure shows the thermistor electrode 107 on the upper surface of the film 104, while the first heating resistor 105 on the lower surface of the film 104 is not shown. Figure 6 (b) in FIG. 1 shows only the pattern on the bottom surface of the film 104 , that is, only the first heating resistor 105 is shown.

[0111] Figure 6 (c) and (d) in FIG. 1 show one of the simulation results when a voltage is applied to the first heating resistor 105 . Figure 6 (c) in the figure shows Figure 6 Deformation of the A-A' section in (a) and (b). Figure 6 (d) also shows Figure 6 Deformation of cross section BB' in (a) and (b).

[0112] These results indicate that when the serpentine heating resistor is located only on the bottom surface of film 104, film 104 experiences significant deformation downward (in the -z direction). This is because the first heating resistor 105 is heated, causing film 104 to expand and deform due to the heat. Therefore, when the first heating resistor 105 at the bottom of film 104 expands due to the heat, film 104 itself deforms in the -z direction.

[0113] Figure 7 The simulation results are shown in which the heating resistor is located only on the upper surface of the film 104 . Figure 7 (a) and Figure 7 (b) in FIG. 1 shows a top view of the film 104. Figure 7 (a) in FIG. 1 shows only the pattern on the upper surface of the film 104. That is, it shows the thermistor electrode 107 and the second heating resistor 106 on the upper surface of the film 104. On the other hand, Figure 7 (b) shows the pattern on the bottom surface of the film 104. However, Figure 7 In the configuration of FIG, there is no pattern on the bottom surface of the film 104. Therefore, this is not described.

[0114] Figure 7 (c) and (d) are schematic diagrams showing deformation of the film 104. They show simulation results when a voltage is applied to the second heating resistor 106. Figure 7 (c) in the figure shows Figure 7 Deformation of cross section AA' in (a) and (b). Figure 7 (d) also shows Figure 7Deformation of cross-sections BB' in (a) and (b) of the figure. These results indicate that when the meandering heating resistor is present only on the top surface of film 104, film 104 experiences significant deformation in the upward direction (+z direction). This is because the second heating resistor 106 is heated, causing thermal expansion and deformation of film 104. Therefore, when the second heating resistor 106 on the top surface of film 104 expands due to heat, film 104 itself deforms in the +z direction.

[0115] Compare Figure 6 and Figure 7 It can be seen that in Figure 6 In the configuration, a meandering heating resistor is provided on the bottom surface of the film 104, and Figure 7 In the configuration of the zigzag heating resistor, a zigzag heating resistor is provided on the top surface of the film 104, which causes the deformation direction of the film 104 to be different. This is because the significant expansion of the electrode in the zigzag longitudinal direction is the main cause of the deformation of the film 104.

[0116] Next, use Figure 8 Based on Figures 1 to 4 The simulation results of the first heating resistor 105 and the second heating resistor 106 above and below the film 104 of the first embodiment will be described. Figure 8 (a) and Figure 8 (b) in FIG. 1 shows a top view of the film 104. Figure 8 (a) in FIG. 1 shows only the pattern on the upper surface of the film 104. That is, it shows the thermistor electrode 107 and the second heating resistor 106 on the upper surface of the film 104. On the other hand, Figure 7 (b) in FIG. 1 shows the pattern on the bottom surface of the film 104. That is, it shows the first heating resistor 105 on the bottom surface of the film 104.

[0117] Figure 8 (c) and (d) in FIG. 1 show one of the simulation results when voltage is applied to the first heating resistor 105 and the second heating resistor 106 . Figure 8 (c) in the figure shows Figure 8 Deformation of cross section AA' in (a) and (b). Figure 8 (d) in the figure shows Figure 8 The deformation of the B-B' section in (a) and (b). Figure 8 The overall result is that the deformation of the film 104 is suppressed. Figures 6 to 8 The result, in Figure 9 A comparison chart is drawn in Figure 9 Shown as Figures 6 to 8 Schematic diagram for comparison of simulation results.

[0118] Figure 9Shows Figures 6 to 8 Changes in the top surface of the membrane in the simulation results. Figure 9 (a) and Figure 6 (c) Figure 7 (c) and Figure 8 (c) in the figure corresponds to the figure, which shows how the z-axis direction changes with the position of the membrane on the x-coordinate, with the membrane center x=0 as the x-coordinate.

[0119] Figure 9 (b) and Figure 6 (d) Figure 7 (d) and Figure 8 (d) in FIG. 3 corresponds to FIG. 4 , which shows how the Z-axis direction changes with the position of the membrane on the Y coordinate, with the center of the membrane being y=0. Figure 9 The solid line in Figure 6 The simulation results are shown in Figure 2. Figure 9 A dotted line in the Figure 7 The simulation results are plotted, and for the sake of comparison, the applied voltage is the same. That is, in the above simulation, Figure 6 The voltage applied to the first heating resistor 105 is Figure 7 The voltage applied to the second heating resistor 106 is the same. Figure 9 Another dotted line in the Figure 8 The simulation results are similarly applied to Figure 8 The voltages of the first heating resistor 105 and the second heating resistor 106 are also the same.

[0120] Figure 8 The simulation of applying voltage to the first heating resistor 105 and the second heating resistor 106 will naturally consume more electricity and generate more heat, but the deformation is smaller than Figure 6 and Figure 7 This indicates that the first heating resistor 105 and the second heating resistor 106 attempt to deform in opposite directions, thereby canceling out each other's displacement in the Z-axis direction. In other words, the configuration according to the first embodiment of the present invention can greatly reduce the deformation of the film 104.

[0121] As described above, if a first heating resistor 105 is provided on the lower surface of the film 104 and a second heating resistor 106 is provided on the upper surface of the film 104, and a voltage is applied to the second heating resistor 106 at the same time, the deformation of the film 104 in the Z-axis direction can be reduced, and deformation in the Z-axis direction caused by long-term stress and heat can be suppressed. This can reduce the deformation of the film 104 in the Z-axis direction and suppress deformation in the Z-axis direction caused by long-term stress and heat. This also suppresses the resistance change of the thermistor caused by deformation, ensuring the performance of the sensor.

[0122] Figure 8 The simulation results show the case where voltage is applied simultaneously to the first and second heating resistors 105, 106. However, when the film 104 is made of a very thin film, voltage can be applied to only the first or second heating resistor 105, 106 to generate heat. If heat is generated, the heat flow can propagate through the film to the other heating resistor, thereby simultaneously heating the first and second heating resistors 105, 106 and achieving simultaneous thermal expansion. Therefore, applying voltage to only one of the heating resistors heats both and produces a displacement-cancelling effect. To achieve mutual thermal compensation between the first and second heating resistors 105, 106, the distance between them should be as short as possible. The linear portion at the outermost edge of the nonlinear serpentine shape is particularly helpful in reducing displacement of the film 104. Therefore, the end linear portions of the first and second heating resistors 105, 106 at least partially overlap, thereby canceling out the thermal stress caused by the first and second heating resistors 105, 106.

[0123] Figure 3 One end 105a of the first heating resistor 105 is located at the start of the meandering shape, indicating the first embodiment; Figure 4 In the figure, one end 105b of the second heating resistor 106 is located at the end of the serpentine shape, representing a second embodiment. One end 106a and one end 106b of the second heating resistor 106 are located at the starting and ending points of the serpentine shape of the first heating resistor 105 and the second heating resistor 106, respectively, so that they overlap above and below the film 104. This structure can make the thermal coupling between the first heating resistor 105 and the second heating resistor 106 particularly strong at the outermost edge of the serpentine shape, thereby effectively suppressing deformation.

[0124] The configuration and positioning of the first and second heating resistors 105 and 106 within the film 104 assembly are crucial for minimizing deformation of the film 104 in the Z-axis direction, as the heating resistors experience greater thermal expansion due to heating than the other components. For example, in the first embodiment, the serpentine direction of the first and second heating resistors 105 and 106 is rotated 180°. This allows many straight portions of the serpentine shape to overlap with the top and bottom of the film 104, achieving enhanced deformation control.

[0125] like Figure 3 and Figure 4As shown, the top surface of the film 104 is provided with a thermistor 107, and the serpentine shape of the first heating resistor 105 can extend to overlap below the thermistor 107. If there is no pattern at the bottom of the film 104 where the thermistor 107 is provided, only the thermistor 107 will expand due to heating, which can easily cause deformation of the film 104. However, if the first heating resistor 105 is also provided below the thermistor 107, the first heating resistor 105 will also expand due to heat, and the deformation of the thermistor 107 will be offset.

[0126] While the above description focuses on deformation caused by thermal stress, from the perspective of effectively heating the thermistor, the configuration of first heating resistor 105 and second heating resistor 106 allows heat generated by first heating resistor 105 to dissipate from below the thermistor, while heat generated by second heating resistor 106, positioned flush against the thermistor, dissipates from the side of the thermistor, effectively heating the thermistor. This configuration not only reduces deformation of film 104 caused by thermal stress from the heating resistors but also effectively heats the thermistor.

[0127] Second embodiment:

[0128] In the first embodiment, the first heating resistor 105 is arranged on the lower surface of the film 104, and the second heating resistor 106 is arranged on the upper surface of the film 104. The configuration shown in the first embodiment requires insulation treatment of the substrate 102 and the first heating resistor 105. Therefore, it is necessary to provide a contact surface 111 for the first heating resistor 105 and the pad 113, and to bond the first heating resistor 105 and the pad 113 together, which makes the manufacturing process complicated.

[0129] If an insulating layer is provided under the first heating resistor 105, it is easier to manufacture the first heating resistor 105. In this way, the first heating resistor 105 is not provided on the lower surface of the film 104, and the present invention is also applicable to this structure.

[0130] See Figures 10 to 13 , Figure 10 FIG2 shows a schematic diagram of the structure of the second embodiment of the present invention. In the first embodiment, the first heating resistor 105 is located at the bottom of the film 104. In the second embodiment, the film includes a thermistor material 108, a thermistor electrode 107, a second heating resistor, and a first insulator. Figure 11As shown, the thermistor electrode 107 and the second heating resistor 106 are located in the same plane, and the thermistor material 108 at least partially covers the thermistor electrode 107 and the second heating resistor 106. The first insulator 110a is provided below the second heating resistor 106 and partially covers the first heating resistor 105. The first heating resistor 105 is provided on a side of the first insulator 110a away from the second heating resistor 106. Preferably, the sensor element further includes a second insulator 110b, which is provided below the first heating resistor 105.

[0131] As can be seen from the above, the first heating resistor 105 is sandwiched between the first insulator 110a and the second insulator 110b, so the contact surface 111 between the first heating resistor 105 and the pad 113 is no longer required. As for other configurations, the second embodiment is the same as the first embodiment and will not be repeated here.

[0132] Figure 11 A side view (-y axis direction) of a second embodiment of the present invention is shown. Figure 12 yes Figure 11 Top view of the A plane (+z axis direction). Figure 13 yes Figure 11 The top view of plane B (+z axis direction) in the figure. Figure 13 In the figure, the first heating resistor 105 and the bonding wire 109a on the bottom surface of the film 104 are omitted to facilitate viewing of the structure of the top surface of the film 104. In this case, as in the first embodiment, if the first heating resistor 105 is located below the middle of the film 104 in the thickness direction, when a voltage is applied to the first heating resistor 105, the first heating resistor 105 will expand due to Joule heat, in the -z direction, causing the film 104 to sag.

[0133] Therefore, by applying a voltage to the second heating resistor 106 at the same time as the first heating resistor 105, the deformation of the film 104 can be offset as in the first embodiment. Therefore, the first heating resistor 105 does not necessarily have to be disposed on the lower surface of the film 104, but only needs to be disposed below the thickness direction of the film 104, and will not be described in detail here.

[0134] Third embodiment:

[0135] While the first and second embodiments describe the configurations of the first heating resistor 105, the second heating resistor 106, and the thermistor electrode 107, a more effective configuration for canceling displacement in the Z-axis direction is to make the planar configuration of the first heating resistor 105 and the second heating resistor 106 on the film 104 identical to the planar configuration of the thermistor electrode 107. In other words, the planar configuration of the first heating resistor 105 and the planar configuration of the second heating resistor 106 on the film 104 should be identical. If the two planar configurations are identical, Z-axis displacement can be canceled more effectively than in the first and second embodiments.

[0136] Figures 14 to 18 A third embodiment is shown. Figure 14 is a schematic structural diagram of a third embodiment of the present invention, Figure 15 is a side view (along the -y axis direction) of the third embodiment, Figure 16 yes Figure 15 Top view of plane A (+z axis direction), Figure 17 yes Figure 15 The view of plane B from the (+z) direction. Figure 17 In the figure, the first heating resistor 105 and the bonding wire 109a, the second thermistor electrode 115 and the bonding wire 109d on the lower side of the film 104 are omitted so that the structure of the upper surface of the film 104 can be easily seen and no additional details are given here.

[0137] In the third embodiment, not only is the thermistor electrode 107 provided on the surface where the second heating resistor 106 is provided, but a second thermistor electrode 115 is also provided on the surface where the first heating resistor 105 is provided. This is different from the first and second embodiments. In this structure, the straight line portions at the starting and ending points of the serpentine shape of the first heating resistor 105 and the straight line portions at the starting and ending points of the serpentine shape of the second heating resistor 106 preferably overlap at the top and bottom.

[0138] Figure 16 and Figure 17 The gaps d2 and d1 between the second thermistor electrode 115 and the thermistor electrode 107 shown in FIG, as well as the lengths and pattern widths of the opposing electrodes forming the gaps, are also preferably aligned. Having the heater resistor and thermistor electrodes have the same configuration on the top and bottom of the membrane further reduces deformation of the membrane 104 in the Z-axis direction. Figure 18 Schematic diagram of two thermistor electrodes of the third embodiment is shown in FIG, that is, a wiring circuit diagram of the thermistor electrode 107 and the second thermistor electrode 115. This figure shows the circuit when the thermistor electrode 107 and the second thermistor electrode 115 are connected in parallel. Figure 18, RTH1 represents the resistance 207 of the thermistor electrode 107 , and RTH2 represents the resistance 208 of the second thermistor electrode 115 .

[0139] The calculation of the composite resistance in parallel state is shown in the following formula (1):

[0140]

[0141] For example, if the resistance values ​​of RTH1 and RTH2 are the same, then the composite resistance R = RTH1 / 2 = RTH2 / 2. In other words, the resistance value of the composite resistance R is smaller than the resistance value of RTH1 and also smaller than the resistance value of RTH2. This shows that in the third embodiment, the gap distance (i.e. Figure 17 d1 in) and the gap distance between the second thermistor electrode 115 (ie Figure 16 The gap distance d2 in the embodiment 1 can be larger than that in the first and second embodiments to achieve the same resistance value. If the gaps d1 and d2 are too small, the variation caused by etching accuracy will increase. Therefore, the gap distance can be increased as in the third embodiment to improve manufacturing accuracy.

[0142] As described in the first and second embodiments, the thermistor electrode 107 is in contact with the thermistor material 108. However, the second thermistor electrode 115 may or may not be provided with the thermistor material 108. By providing the thermistor material 108, the surface of the thermistor electrode 107 and the surface of the second thermistor electrode 115 have the same structure, which makes the effect of offsetting the displacement in the Z-axis direction more effective. However, the provision of the thermistor material 108 makes the manufacturing process more complicated, so those skilled in the art can make a choice based on actual conditions.

[0143] Fourth embodiment:

[0144] The third embodiment described above describes a configuration in which a second thermistor electrode 115 is provided. The fourth embodiment uses Figures 19-22 The dummy pattern (pseudo pattern) in the configuration replaces the second thermistor electrode 115. Specifically, Figure 19 It is a structural diagram of the fourth embodiment. Figure 20 is a side view (along the -y axis direction) of the fourth embodiment. Figure 21 yes Figure 20 Top view of plane A (+z direction). Figure 22 yes Figure 20 The view of plane B from the (+z) direction. It should be noted that, Figure 22The diagram shows a schematic diagram of plane B shown from the top of the fourth embodiment of the present invention. Since it is a top view (top view), the first heating resistor 105, bonding wire 109a and other components on the lower side of the film 104 are not shown, making it easier to see the structure on the upper side of the film 104.

[0145] As an example of the fourth embodiment, Figure 21 A schematic diagram of the A plane shown at the top of the fourth embodiment of the present invention is shown, wherein Figure 21 An example of providing a U-shaped dummy pattern 114 is shown. If the dummy pattern 114 is not designed, the thermistor electrode 107 itself will undergo thermal expansion after receiving heat, causing the film 104 to deform. Therefore, in the fourth embodiment, a dummy pattern (pseudo-pattern) 114 is provided on the layer of the film 104 relative to the other side of the thermistor electrode 107 and overlapping with the thermistor electrode 107 (for example, on the layer where the first heating resistor 105 is located). In this way, the dummy pattern 114 can also receive the heat flow of the heating resistor and thus also undergo thermal expansion in the opposite direction to the thermal expansion of the thermistor 107, thereby offsetting the deformation of the thermistor electrode 107, and thus the deformation of the film 104 is also suppressed. Figure 21 In the figure, the dummy pattern 114 is shown as a U-shape, but the direction of the U-shape can be rotated 180° from the figure. In other words, it does not have to be a U-shape, but can also be an open O-shape, or it can be implemented as two lines. The provision of the dummy pattern 114 can prevent the film 104 from deforming due to the deformation of the thermistor electrode 107.

[0146] Fifth embodiment

[0147] In the description of the first embodiment, it was explained that when film 104 is formed of a very thin film, if a voltage is applied to either first heating resistor 105 or second heating resistor 106 to generate heat, the heat flow can be transferred through the film to the other heating resistor, thus eliminating the need to apply voltage to both heating resistors. To achieve heat transfer in another manner, a plurality of thermal vias 116 are provided in the fifth embodiment to more effectively facilitate thermal coupling between the two heating resistors.

[0148] Preferably, in order to improve the degree of thermal coupling between the straight lines at the starting and ending points of the serpentine shape of the first heating resistor 105 and the straight lines at the starting and ending points of the serpentine shape of the second heating resistor 106, thermal vias 116 are provided to thermally couple them. The presence of thermal vias 116 makes it possible to heat only one heating resistor, thereby enabling reliable heating of both heating resistors. The provision of thermal vias 116 allows it to achieve thermal contact with the first heating resistor 105 and the second heating resistor 106. Even if it is not in contact with them, as long as they are brought closer, the degree of thermal coupling will be increased.

[0149] Figure 23 FIG. 1 is a schematic structural diagram of a fifth embodiment of the present invention, wherein thermal vias are provided in the first heating resistor and the second heating resistor. Figure 23 and Figure 24 1 shows an example of a configuration in which the first heating resistor 105 and the second heating resistor 106 are in contact with each other through the thermal via 116. Specifically, Figure 23 The first embodiment shows Figure 3 The corresponding plane and depicts the lower pattern of the film 104. That is, the first heating resistor 105, the pad 113a, the bonding wire 109a and the thermal via 116 are shown. Figure 24 The fifth embodiment and the first embodiment are shown Figure 4 The corresponding plan view shows the pattern on the upper side of the film 104. That is, the second heating resistor 106, the thermistor electrode 107 and the thermal via 116 are shown. Figure 23 and Figure 24 In the embodiment, the straight lines at the starting and ending points of the serpentine shape of the first heating resistor 105 and the straight lines at the starting and ending points of the serpentine shape of the second heating resistor 106 are respectively in contact with two thermal vias 116. If the first heating resistor 105 and the second heating resistor 106 are in full electrical contact through the thermal vias 116, then if voltage is applied to only the first heating resistor 105 or the second heating resistor 106, current will flow to the other heating resistor and generate heat through Joule heat. Figure 23 and Figure 24 In the illustrated configuration, voltage is applied only to the first heating resistor 105, and the bonding wire on one side of the second heating resistor 106 is removed, which will not be described in detail here. In this configuration, the thermal expansion of the first and second heating resistors 105, 106 due to Joule heat can also offset the displacement of the heating electrode patterns on the film 104 caused by each other.

[0150] Furthermore, even if the first heating resistor 105 and the second heating resistor 106 are not in full contact, but are only brought closer together by the thermal vias 116, the thermal coupling effect is enhanced. Therefore, even if voltage is applied to only the first heating resistor 105 or the second heating resistor 106, both heating resistors will experience thermal expansion, thereby offsetting the deformation of the film 104. In other words, there is no need to apply voltage to both heating resistors.

[0151] The first to fifth embodiments described above are for describing the present invention, but the present invention can be applied in various other forms. For example, Figure 5A configuration is shown in which the first heating resistor 105 and the second heating resistor 106 are simply connected in parallel to the voltage source 201. However, if it is necessary to apply voltage to the two heating electrodes and heat them at the same time, other circuit elements such as resistors, inductors, capacitors, and semiconductor elements may also be connected in parallel to the voltage source 201. Other circuit elements such as resistors, inductors, capacitors, and semiconductor elements may also be included. For example, Figure 25 As shown, Figure 25 It is a schematic diagram of a circuit for driving the first heating resistor and the second heating resistor according to the present invention, wherein the circuit configuration of the series circuit 204 included therein can be selected according to actual needs.

[0152] In addition, the bridge circuit configuration often used in sensor circuits is also optional. If a voltage can be applied to the resistance 202 of the first heating resistor and the resistance 203 of the second heating resistor at the same time, the effect of offsetting deformation of the present invention can be achieved. A combination of the first heating resistor 105 and the second heating resistor 106 in multiple circuits is also optional. In addition, the first heating resistor and the second heating resistor are defaulted to two layers. If the structure of the multi-layer heating resistor can also offset each other, it also falls within the scope of protection of the present invention, that is, the first and second do not constitute a limitation on quantity.

[0153] Figure 5 The voltage source 201 in FIG. 2 is shown as a simple ON / OFF pulse source, but it may have a configuration such as detecting the outside air temperature, feeding back and adjusting the voltage level, switching the voltage level as needed, and the like. Figure 26 Shown is a schematic diagram of a circuit with a voltage amplifier according to the present invention, Figure 26 The circuit example in FIG. 1 includes voltage amplifiers A1 and A2, which can provide different levels of voltage to the resistor 202 of the first heating resistor and the resistor 203 of the second heating resistor, respectively.

[0154] Furthermore, regarding voltage, when the sensor is working, the voltage applied to the first heating resistor 105 is a first voltage V1, and the voltage applied to the second heating resistor 106 is a second voltage V2. The first voltage V1 is greater than or equal to the second voltage V2. For details, see Figure 38 , Figure 38 FIG. 1 is a graph showing a correlation curve in one embodiment of the present invention, wherein Figure 38 The left side (a) is a graph showing the relationship between heat and position. Figure 38 The graph (b) on the right shows the relationship between displacement and position. Each graph contains three pieces of data. Among the temperature distribution of these data, the temperature of the detection part of the gas sensor is important. Therefore, the voltages of V1 and V2 are adjusted so that Figure 38 In (a), the temperature between A and A' is constant. That is, in order to make the temperature between A and A' the same, it is necessary to adjust the levels of the voltage V1 applied to the first heating resistor 105 and the voltage V2 applied to the second heating resistor 106, specifically including three situations: V1 < V2, V1 = V2, and V1 > V2.

[0155] like Figure 38 As shown in (a), it can be seen that in the case of V1<V2, excessive heating is required near -30 microns and 30 microns. Excessive heating may cause damage to the gas sensor. In the long run, excessive heating may change the characteristics of the film 104. In addition, as Figure 38 As shown in (b), it is confirmed that the displacement under the condition of V1 < V2 is greater than the displacement under other conditions, that is, adjustment under the condition of V1 = V2 or V1 > V2 can achieve the corresponding temperature stabilization effect.

[0156] In the first and second embodiments, the first heating resistor 105 is disposed at the bottom of the membrane 104, and the second heating resistor 106 and the thermistor electrode 107 are disposed at the top of the membrane 104. The second heating resistor 106 and the thermistor 107 may also be disposed at the bottom of the membrane 104. If the thermistor is disposed at the top or bottom of the membrane 104, the thermistor can come into contact with the incoming gas and can function as a gas sensor.

[0157] In addition, the embodiment of the present invention describes how the soldering pads of the first heating resistor 105, the soldering pads of the second heating resistor 106, the soldering pads of the thermistor electrode 107 and the soldering pads of the second thermistor electrode 115 are arranged so that they do not overlap and are respectively connected to the bonding wires, but in the film 104, regarding the position of the non-existent soldering pads, since it has little effect on the displacement of the film 104 in the Z-axis direction, its configuration is not limited to the configuration of this embodiment.

[0158] The first to fifth embodiments above describe the present invention. To facilitate understanding, various embodiments of the components of the present invention are further illustrated. Figures 27 to 32 , Figure 27 The first shape and structure design of each component of the present invention is shown. In the first shape and structure design, the first heating resistor and the second heating resistor are located in the upper and lower layers of the film, and the thermistor electrode and the second heating resistor are located in the same plane. Figure 28The second shape and structure design of each component of the present invention is shown. The film of the second shape and structure design includes three layers. The lower layer is provided with a first heating resistor, that is, it is provided on the side of the film close to the cavity. The middle layer is provided with a second heating resistor, which can be designed to be located in the middle layer or above the center according to actual needs. The upper layer is provided with a thermistor electrode, and the thermistor material at least partially covers the thermistor electrode. That is, in the second shape and structure design, the first heating resistor, the second heating resistor, and the thermistor electrode are located in different layers. Figure 29 The third shape structure design of each component of the present invention is shown, Figure 27 Unlike the first shape design shown, the third shape design has no padding. Figure 30 The fourth shape and structure design of the components of the present invention is shown. In the fourth shape and structure design, the second heating resistor and the thermistor electrode are located on the upper layer, and the first heating resistor and the second thermistor electrode are located on the lower layer. Figure 31 The fifth shape and structure design of each component of the present invention is shown. The fifth shape and structure design introduces a false pattern (pseudo pattern). The first heating resistor and the false pattern are arranged in the lower layer, and the second heating resistor and the thermistor electrode are arranged in the upper layer. Figure 32 The sixth shape and structure design of each component of the present invention is shown. The sixth shape and structure design introduces a thermal via. The first heating resistor and the corresponding thermal via are arranged in the lower layer, and the second heating resistor, thermistor electrode and the corresponding thermal via are arranged in the upper layer. Figures 27 to 32 The different structural designs of the core components such as the first heating resistor, the second heating resistor, the thermistor electrode, the dummy pattern (false pattern), and the thermal via are shown in each of the figures. Those skilled in the art can choose according to actual design requirements, and of course are not limited to the first to fifth embodiments and the Figures 27 to 32 The structural design will not be described in detail here.

[0159] Similarly, for ease of understanding, various structural designs of the pseudo pattern (false pattern) of the present invention are further demonstrated, see Figures 33 to 37 , Figure 33 A schematic plan view of a dummy pattern having a first structure according to the present invention is shown. Figure 34 A schematic plan view of a second structure of a false pattern according to the present invention is shown. Figure 35 A schematic plan view of a false pattern having a third structure according to the present invention is shown. Figure 36 A schematic plan view of a dummy pattern having a fourth structure according to the present invention is shown. Figure 37 The present invention is provided with a fifth structure of the dummy pattern of the plane schematic diagram, from the above Figures 33 to 37 It can be seen that the pseudo pattern (false pattern) can be designed in a variety of designs such as U-shape, surface shape, O-shape or line shape, and of course it is not limited to the above. Figures 33 to 37 The structural design will not be described in detail here.

[0160] Another embodiment of the present invention provides a gas sensor comprising the sensor element described above. Multiple sensor elements 101 can be manufactured according to the present invention and combined to form a gas sensor. According to the present invention, multiple sensor elements 101 can also be disposed on a single substrate 102. Since multiple sensor elements 101 can be disposed on a single substrate 102, the sensor elements 101 can be arranged adjacent to each other, thereby reducing the mounting area. This is not specifically limited here.

[0161] The sensor element and gas sensor provided by the embodiments of the present invention have the following beneficial effects:

[0162] The first heating resistor and the second heating resistor cooperate with each other. The thermal stress in the film thickness direction caused by the heat generated by the first heating resistor and the thermal stress in the film thickness direction caused by the heat generated by the second heating resistor are in opposite directions, which can offset each other's stresses and make the thermal stresses in the film thickness direction offset each other. The thermal stress in the film thickness direction can be significantly reduced, effectively avoiding deformation of the membrane structure, making the resistance characteristics in the gas sensor stable and not easy to change, thereby ensuring the stable performance of the gas sensor.

[0163] The above-described embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

Claims

1. A sensor element, characterized in that: comprising a substrate and a film disposed on the substrate; The base has a cavity and an opening communicating with the cavity; The film is supported on the opening and partially covers the cavity; The film includes a first heating resistor and a second heating resistor, both of which are formed by zigzag lines. The first heating resistor is arranged on a side of the film close to the cavity, and the second heating resistor is arranged on a side of the film away from the cavity. The end linear portion of the first heating resistor and the end linear portion of the second heating resistor at least partially overlap, so that thermal stress caused by the first heating resistor and thermal stress caused by the second heating resistor offset each other.

2. The sensor element according to claim 1, wherein The film also includes a thermistor electrode and a thermistor material; The thermistor electrode and the first heating resistor or the second heating resistor are located in the same plane, and the thermistor material at least partially covers the thermistor electrode.

3. The sensor element according to claim 1, wherein The film also includes a thermistor electrode and a thermistor material; The first heating resistor is arranged on a side of the film close to the cavity; The second heating resistor is arranged on a side of the film away from the first heating resistor; The thermistor electrode is arranged on a side of the film away from the second heating resistor, and the thermistor material at least partially covers the thermistor electrode.

4. The sensor element according to claim 2, wherein The film further includes a first thermistor electrode, a first thermistor material, and a second thermistor electrode; The first thermistor electrode and the first heating resistor are located in the same plane, and the first thermistor material at least partially covers the first thermistor electrode; the second thermistor electrode and the second heating resistor are located in the same plane.

5. The sensor element according to claim 4, wherein The film also includes a second thermistor material that at least partially covers the second thermistor electrode.

6. The sensor element according to claim 2, wherein The thermistor electrode is disposed in a nonlinear portion of the first heating resistor element or the second heating resistor element.

7. The sensor element according to claim 1, wherein The bending direction of the nonlinear portion of the first heating resistor is rotated by 180° relative to the bending direction of the nonlinear portion of the second heating resistor.

8. The sensor element according to claim 1, wherein The first heating resistor and the second heating resistor are connected in parallel in a circuit.

9. The sensor element according to claim 8, wherein The circuit is further provided with a voltage amplifier to adjust the voltage applied to the first heating resistor and the second heating resistor.

10. The sensor element according to claim 1, wherein The film further includes an insulator disposed between the first heating resistor and the second heating resistor, and the first heating resistor and the second heating resistor are isolated from each other by the insulator.

11. The sensor element according to claim 2, wherein The film further includes a first insulator; The thermistor electrode and the second heating resistor are located in the same plane, and the thermistor material at least partially covers the thermistor electrode and the second heating resistor; The first insulator is disposed under the second heating resistor. The first insulator partially covers the first heating resistor. The first heating resistor is disposed on a side of the first insulator away from the second heating resistor.

12. The sensor element according to claim 11, wherein The sensor element further includes a second insulator; The second insulator is provided on a lower layer of the first heating resistor.

13. The sensor element according to claim 2, wherein The film has a dummy pattern configured to receive heat and expand to offset deformation generated by the thermistor electrode.

14. The sensor element according to claim 1, wherein The sensor element is further provided with a plurality of thermal vias, and the first heating resistor and the second heating resistor are thermally coupled via the thermal vias.

15. The sensor element according to claim 1, wherein When the sensor is working, the voltage applied to the first heating resistor is a first voltage, the voltage applied to the second heating resistor is a second voltage, and the first voltage is greater than or equal to the second voltage.

16. A gas sensor, characterized in that: Comprising the sensor element according to claim 1.

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