Hydrogen sensor and preparation method thereof

Abstract

The invention relates to the technical field of hydrogen sensors, in particular to a hydrogen sensor and a preparation method thereof.The hydrogen sensor comprises two first working resistors which are metal thermal resistors, two second working resistors which are palladium alloy film resistors and a heating resistor, and the heating resistor is used for heating the second working resistors to the working temperature; the second working resistor is arranged in a heating area of the heating resistor; the hydrogen sensor is configured to be switchable among a first mode, a second mode, a third mode and a fourth mode; in the first mode, one first working resistor and one second working resistor are connected in series to form a detection unit, and the two detection units are connected in parallel to work; in the second mode, one detection unit works; in the third mode, the two first working resistors work in a time-sharing manner; and in the fourth mode, the two second working resistors work in a time-sharing manner. The hydrogen sensor provided by the invention has high sensitivity in a full-scale detection range of hydrogen concentration, and can realize accurate and rapid hydrogen detection in various application scenarios.

Description

Technical Field

[0001] The present invention relates to the technical field of hydrogen sensors, and in particular to a hydrogen sensor and a preparation method thereof. Background Art

[0002] Hydrogen fuel cells have been widely used in the fields of automobiles, nuclear power, etc. In order to avoid explosions caused by hydrogen leakage, the measurement of hydrogen leakage in the preparation, transportation, storage and utilization of hydrogen has become an issue that urgently needs attention and resolution.

[0003] High sensitivity is one of the main goals of hydrogen sensor design. In hydrogen sensors, the conventional method to improve sensitivity is to configure a Wheatstone bridge and set a working resistor with a resistance of r1 on two opposite bridge arms of the Wheatstone bridge, and set a non-working resistor with a resistance of r2 on the remaining two bridge arms. When r1=r2, the sensitivity of the hydrogen sensor is the highest.

[0004] Although this structure optimizes the sensitivity of the hydrogen sensor to a certain extent, its optimization degree is limited. In addition, this type of hydrogen sensor with a single detection principle is difficult to achieve accurate and rapid detection in a variety of application scenarios. Summary of the invention

[0005] To this end, the technical problem to be solved by the present invention is to overcome the problem that the existing hydrogen sensors have low sensitivity and are difficult to achieve accurate and rapid detection in various application scenarios, and to provide a hydrogen sensor and a preparation method thereof, which have high sensitivity within the full range of hydrogen concentration detection and can achieve accurate and rapid hydrogen detection in various application scenarios.

[0006] In a first aspect, the present invention provides a hydrogen sensor, comprising a first component, the first component comprising two first working resistors, the first working resistors being metal thermal resistors; a second component, the second component comprising two second working resistors, the second working resistors being palladium alloy thin film resistors; and a third component, the third component comprising a heating resistor, the heating resistor being used to heat the second working resistors to a working temperature, and the two second working resistors are both arranged in a heating area of ​​the heating resistor; wherein the hydrogen sensor is configured to be switchable between a first mode, a second mode, a third mode and a fourth mode; when in the first mode, one first working resistor and one second working resistor are connected in series to form a detection unit, and the two detection units are connected in parallel to work; when in the second mode, one detection unit works; when in the third mode, the two first working resistors work in time sharing; when in the fourth mode, the two second working resistors work in time sharing.

[0007] In one embodiment of the present invention, when no power is supplied and no hydrogen is supplied, the resistance of the first working resistor is R1, and the resistance of the second working resistor is R2; when power is supplied and hydrogen is supplied, the resistance of the first working resistor is R1-ΔR1, and the resistance of the second working resistor is R2+ΔR2. The first working resistor and the second working resistor are selected so that the sensitivity in the first mode and the second mode is maximum.

[0008] In one embodiment of the present invention, the first component further includes a first lead, a first electrode, a first pad, a second lead, a second electrode, and a second pad; one end of the first lead is electrically connected to one end of the first working resistor, the other end of the first lead is electrically connected to the first electrode, the first pad is covered and arranged on the first electrode and is electrically connected thereto, wherein the width of at least part of the first lead gradually decreases from one end thereof to the end connected to the first working resistor; one end of the second lead is electrically connected to the other end of the first working resistor, the other end of the second lead is electrically connected to the second electrode, the second pad is covered and arranged on the second electrode and is electrically connected thereto, wherein the width of at least part of the second lead gradually decreases from one end thereof to the end connected to the first working resistor The width of the third lead gradually decreases from one end to the end connected to the second working resistor; the second component also includes a third lead, a third electrode, a third pad, a fourth lead, a fourth electrode and a fourth pad, one end of the third lead is electrically connected to one end of the second working resistor, the other end of the third lead is electrically connected to the third electrode, the third pad is covered on the third electrode and is electrically connected thereto, wherein the width of at least part of the third lead gradually decreases from one end thereof to the end connected to the second working resistor; one end of the fourth lead is electrically connected to the other end of the second working resistor, the other end of the fourth lead is electrically connected to the fourth electrode, the fourth pad is covered on the fourth electrode and is electrically connected thereto, wherein the width of at least part of the fourth lead gradually decreases from one end thereof to the end connected to the second working resistor.

[0009] In one embodiment of the present invention, the two first working resistors are symmetrically arranged about a first symmetry axis, the two second working resistors are symmetrically arranged about the first symmetry axis, and the first symmetry axis is parallel to the first direction; the first component and the second component are symmetrically arranged about a second symmetry axis, and the second symmetry axis is parallel to the second direction.

[0010] In one embodiment of the present invention, the first working resistor includes at least one first bending portion and at least one second bending portion, the bending directions of the first bending portion and the second bending portion are opposite, and the first bending portion and the second bending portion are alternately arranged in sequence; or / and the second working resistor includes at least one third bending portion and at least one fourth bending portion, the bending directions of the third bending portion and the fourth bending portion are opposite, and the third bending portion and the fourth bending portion are alternately arranged in sequence.

[0011] In one embodiment of the present invention, the heating resistor includes at least one fifth bending portion and at least one sixth bending portion, the bending directions of the fifth bending portion and the sixth bending portion are opposite, and the fifth bending portion and the sixth bending portion are alternately arranged in sequence.

[0012] In one embodiment of the present invention, the third component also includes a fifth lead, a fifth electrode, a fifth pad, a sixth lead, a sixth electrode and a sixth pad; one end of the fifth lead is electrically connected to one end of the heating resistor, the other end of the fifth lead is electrically connected to the fifth electrode, the fifth pad is covered on the fifth electrode and electrically connected thereto, wherein the width of at least part of the fifth lead gradually decreases from one end thereof to the end connected to the heating resistor; one end of the sixth lead is electrically connected to the other end of the heating resistor, the other end of the sixth lead is electrically connected to the sixth electrode, the sixth pad is covered on the sixth electrode and electrically connected thereto, wherein the width of at least part of the sixth lead gradually decreases from one end thereof to the end connected to the heating resistor.

[0013] In one embodiment of the present invention, it also includes a substrate, the substrate includes a first plane and a second plane arranged relatively to each other along a third direction, the first plane is provided with an insulation groove extending through the second plane; and a membrane layer assembly, the membrane layer assembly has an insulation area corresponding to the insulation groove, the membrane layer assembly includes a first membrane layer and a second membrane layer, the first membrane layer is covered and arranged on the first plane, the first working resistor and the heating resistor are arranged above the first membrane layer, and the first working resistor and the heating resistor are both arranged in the insulation area, the second membrane layer is covered and arranged above the first working resistor and the heating resistor, and the second working resistor is arranged above the second membrane layer.

[0014] In one embodiment of the present invention, a ventilation cavity is provided on the second plane, the ventilation cavity extends along the first direction, and the ventilation cavity is communicated with the thermal insulation groove.

[0015] In a second aspect, the present invention further provides a method for preparing a hydrogen sensor, which is used to prepare a hydrogen sensor as described in any one of the above, comprising the following steps:

[0016] S1, depositing a first film layer on a first plane of a substrate;

[0017] S2, forming a first working resistor, a heating resistor, a lead and an electrode on the first film layer;

[0018] S3, forming a second film layer on the first film layer, wherein the second film layer covers the first working resistor, the heating resistor and the lead wire;

[0019] S4, forming a second working resistor on the second film layer;

[0020] S5, forming a pad on the electrode;

[0021] S6, etching a ventilation cavity on a second plane of the substrate, wherein the second plane is arranged opposite to the first plane;

[0022] S7, etching a thermal insulation groove on the ventilation cavity to obtain a hydrogen sensor.

[0023] The above technical solution of the present invention has the following beneficial effects compared with the prior art:

[0024] The hydrogen sensor described in the present invention, firstly, configures the bridge according to the effect of thermal conductivity principle and palladium hydrogen absorption principle on resistance, so that the sensor has high sensitivity in the full range of hydrogen concentration. Secondly, when facing hydrogen leakage monitoring in different application scenarios, it can switch between four modes, and does not require oxygen participation during operation, and has a wide range of application scenarios. Finally, due to the combination of the advantages of thermal conductivity principle and palladium hydrogen absorption principle, it has the characteristics of fast response, high precision, long life, and resistance to interference from other gases, and has high comprehensive performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to make the content of the present invention more clearly understood, the present invention is further described in detail below according to specific embodiments of the present invention in conjunction with the accompanying drawings, wherein:

[0026] Figure 1 This is one of the top view structural schematic diagrams of the hydrogen sensor in the preferred embodiment of the present invention;

[0027] Figure 2 This is the second schematic diagram of the top view structure of the hydrogen sensor in the preferred embodiment of the present invention;

[0028] Figure 3 It is a schematic cross-sectional view of a hydrogen sensor in a preferred embodiment of the present invention;

[0029] Figure 4 A schematic diagram of a bridge in the first mode in a preferred embodiment of the present invention;

[0030] Figure 5A schematic diagram of a bridge in the second mode in a preferred embodiment of the present invention;

[0031] Figure 6 It is a structural schematic diagram of the first working resistor in a preferred embodiment of the present invention;

[0032] Figure 7 It is a structural schematic diagram of the second working resistor in a preferred embodiment of the present invention;

[0033] Figure 8 Schematic diagram of the structure of the heating resistor in the preferred embodiment of the present invention.

[0034] Description of the accompanying drawings in the specification: D1, first direction; D2, second direction; D3, third direction; 10, first working resistor; 101, first bending portion; 102, second bending portion; 111, first electrode; 112, first pad; 12, first lead; 131, second electrode; 132, second pad; 14, second lead; 20, second working resistor; 201, third bending portion; 202, fourth bending portion; 211, third electrode; 212, third pad; 22, third lead; 231, fourth electrode ; 232, fourth solder pad; 24, fourth lead; 30, heating resistor; 301, fifth bend; 302, sixth bend; 303, heating area; 311, fifth electrode; 312, fifth solder pad; 32, fifth lead; 331, sixth electrode; 332, sixth solder pad; 34, sixth lead; 40, substrate; 41, first plane; 411, insulation groove; 42, second plane; 421, ventilation cavity; 43, membrane layer assembly; 431, insulation area; 432, first membrane layer; 433, second membrane layer. DETAILED DESCRIPTION

[0035] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.

[0036] Reference Figure 1 , Figure 2 and Figure 3 As shown, the present invention discloses a hydrogen sensor, comprising a first component, a second component and a third component.

[0037] The first component includes two first working resistors 10. The first working resistor 10 is a metal thermal resistor to ensure that its resistance value can change with the change of temperature. The first working resistor 10 works based on the principle of thermal conductivity. Those skilled in the art can set the material of the first working resistor 10 according to actual needs, as long as the resistivity, temperature coefficient of resistivity, stability, conductivity, etc. meet the requirements, for example, platinum, aluminum, gold, etc. Preferably, it is set to platinum, which has a higher temperature coefficient of resistivity and thermal stability and is commonly used to make metal thermal resistors.

[0038] The second component includes two second working resistors 20. The second working resistor 20 is a palladium alloy thin film resistor. The second working resistor 20 works based on the principle of palladium absorbing hydrogen. Palladium alloy is an alloy composed of palladium and other elements, such as palladium / nickel alloy, palladium / silver alloy, palladium / gold alloy, palladium / copper alloy, etc. The palladium alloy film solves the problem of easy cracking and delamination of pure palladium film, while retaining the characteristic that palladium has a specific selectivity for hydrogen, and can also shorten the response time and improve the stability and reliability of the sensitive film.

[0039] The third component includes a heating resistor 30, which is used to heat the second working resistor 20. The two second working resistors 20 are both arranged in the heating area 303 of the heating resistor 30 so that the heating resistor 30 is heated to reach the working temperature for operation. In the figure, the heating area 303 is indicated by a double dotted line. The material of the heating resistor 30 can be any one of gold, platinum, tungsten, and nickel-chromium alloy, so that the heating resistor 30 can provide a stable and uniform temperature field, improve the sensitivity of the second working resistor 20, and thus make the hydrogen sensor respond quickly. Preferably, the material is set to platinum to take into account both high temperature stability and chemical stability.

[0040] When performing hydrogen concentration detection, the hydrogen sensor is configured to be switchable among a first mode, a second mode, a third mode and a fourth mode.

[0041] Specifically, in the first mode, a first working resistor 10 and a second working resistor 20 are connected in series to form a detection unit, and the two detection units are connected in parallel to work. Figure 4 As shown, in the first mode, two detection units connected in parallel form a Wheatstone bridge, two first working resistors 10 are arranged on two opposite bridge arms of the Wheatstone bridge, and two second working resistors 20 are arranged on the remaining two bridge arms of the Wheatstone bridge. In the figure, VCC and GND represent the power supply voltage, V out Represents the output voltage. Those skilled in the art can set a constant voltage source or a constant current source for power supply according to requirements.

[0042] After power is turned on, the temperature of the first working resistor 10 rises rapidly. Since hydrogen has high thermal conductivity, after hydrogen is passed, the heat of the first working resistor 10 is taken away by hydrogen, and its resistance decreases. The greater the hydrogen concentration, the greater the value of the resistance reduction of the first working resistor 10. While the second working resistor 20 at the working temperature, hydrogen molecules dissociate into hydrogen atoms on the palladium surface, and the hydrogen atoms diffuse into the interior of the palladium lattice, and the resistivity of the palladium alloy increases, so that the resistance of the second working resistor 20 increases. The greater the hydrogen concentration, the greater the value of the resistance increase of the second working resistor 20.

[0043] In the first mode, according to the principle of the Wheatstone bridge, when the resistance values ​​of the two oppositely arranged bridge arms increase and the resistance values ​​of the other two bridge arms decrease during operation, the circuit has high sensitivity.

[0044] At the same time, the first working resistor 10 based on the thermal conductivity principle has a fast response speed, but its accuracy is low when detecting low-concentration hydrogen; while the second working resistor 20 based on the palladium hydrogen absorption principle has a specific selectivity for hydrogen, can resist interference from other gases, and has high accuracy when detecting low concentrations, but its response speed is slow. The two work together to complement each other, so that the hydrogen sensor has the characteristics of strong anti-interference, fast response speed and high accuracy.

[0045] In addition, both resistors can work under the condition of hydrogen volume concentration percentage of 0 to 100% and without oxygen, and do not consume hydrogen during operation, so the hydrogen sensor of the present invention also has the characteristics of large range and long life. The hydrogen sensor in the first mode is particularly suitable for full-range hydrogen concentration detection scenarios with no requirements on power consumption and high requirements on comprehensive hydrogen detection performance.

[0046] In the second mode, one detection unit is in operation. Figure 5 As shown, the working process of the hydrogen sensor in the second mode is the same as that in the first mode, except that the second mode is a half-bridge structure, and its power consumption is lower than that in the first mode. The hydrogen sensor in the second mode is particularly suitable for full-range hydrogen concentration detection scenarios that have requirements on power consumption and high requirements on the comprehensive performance of hydrogen detection.

[0047] When in the third mode, the two first working resistors 10 work in time-sharing. In the third mode, the two first working resistors 10 are used as independent hydrogen sensing ends, with low power consumption and fast response characteristics based on the thermal conductivity principle, and can achieve full-scale hydrogen concentration detection. Specifically, when one of the first working resistors 10 fails, the other first working resistor 10 can serve as a backup to undertake hydrogen detection work. This redundant working mode has the characteristics of high reliability and long life. The hydrogen sensor in the third mode is particularly suitable for harsh scenarios with high requirements on power consumption and response speed for full-scale hydrogen concentration detection.

[0048] When in the fourth mode, the two second working resistors 20 work in time-sharing. In the fourth mode, the two second working resistors 20 are used as independent hydrogen sensing ends with low power consumption, and have the characteristics of high low-concentration detection accuracy based on the palladium hydrogen absorption principle and resistance to interference from other gases, and can achieve full-scale hydrogen concentration detection. Specifically, when one of the second working resistors 20 fails, the other second working resistor 20 can serve as a backup to undertake hydrogen detection work. This redundant working mode has the characteristics of high reliability and long life. The hydrogen sensor in the fourth mode is particularly suitable for harsh scenarios with high requirements for accuracy, power consumption and anti-interference for full-scale detection of hydrogen concentration.

[0049] The hydrogen sensor described in the present invention, firstly, configures the bridge according to the effect of thermal conductivity principle and palladium hydrogen absorption principle on resistance, so that the sensor has high sensitivity in the full range of hydrogen concentration. Secondly, when facing hydrogen leakage monitoring in different application scenarios, it can switch between four modes, and does not require oxygen participation during operation, and has a wide range of application scenarios. Finally, due to the combination of the advantages of thermal conductivity principle and palladium hydrogen absorption principle, it has the characteristics of fast response, high precision, long life, and resistance to interference from other gases, and has high comprehensive performance.

[0050] In some embodiments of the hydrogen sensor of the present invention, when no power is supplied and no hydrogen is passed, the resistance of the first working resistor 10 is R1, and the resistance of the second working resistor 20 is R2. When power is supplied and hydrogen is passed, the resistance of the first working resistor 10 is R1-ΔR1, and the resistance of the second working resistor 20 is R2+ΔR2. The first working resistor 10 and the second working resistor 20 whose performance parameters satisfy R1=R2 and ΔR1=ΔR2 are selected so that the sensitivity in the first mode and the second mode is the maximum value. Those skilled in the art can satisfy R1=R2 and ΔR1=ΔR2 according to actual needs; illustratively, it can be achieved by changing the shape of the resistor and the reaction area.

[0051] In some embodiments of the hydrogen sensor of the present invention, the first component further includes a first lead 12 , a first electrode 111 , a first pad 112 , a second lead 14 , a second electrode 131 , and a second pad 132 .

[0052] Reference Figure 1 and Figure 6 As shown, one end of the first lead 12 is electrically connected to one end of the first working resistor 10, the other end of the first lead 12 is electrically connected to the first electrode 111, and the first pad 112 is covered and electrically connected to the first electrode 111. The width of at least part of the first lead 12 gradually decreases from one end thereof to the end connected to the first working resistor 10. Preferably, the first lead 12 includes a connected rectangular lead portion and a trapezoidal lead portion.

[0053] One end of the second lead 14 is electrically connected to the other end of the first working resistor 10, and the other end of the second lead 14 is electrically connected to the second electrode 131. The second pad 132 is covered and electrically connected to the second electrode 131. The width of at least part of the second lead 14 gradually decreases from one end thereof to the end connected to the first working resistor 10. Preferably, the second lead 14 is arranged in an isosceles trapezoidal structure.

[0054] The second component further includes a third lead 22 , a third electrode 211 , a third pad 212 , a fourth lead 24 , a fourth electrode 231 , and a fourth pad 232 .

[0055] Reference Figure 1 and Figure 7 As shown, one end of the third lead 22 is electrically connected to one end of the second working resistor 20, the other end of the third lead 22 is electrically connected to the third electrode 211, and the third pad 212 is covered and electrically connected to the third electrode 211. The width of at least part of the third lead 22 gradually decreases from one end thereof to the end connected to the second working resistor 20. Preferably, the third lead 22 includes a connected rectangular lead portion and a trapezoidal lead portion.

[0056] One end of the fourth lead 24 is electrically connected to the other end of the second working resistor 20, and the other end of the fourth lead 24 is electrically connected to the fourth electrode 231. The fourth pad 232 is covered and electrically connected to the fourth electrode 231. The width of at least part of the fourth lead 24 gradually decreases from one end thereof to the end connected to the second working resistor 20. Preferably, the fourth lead 24 is arranged in an isosceles trapezoidal structure.

[0057] Since the hydrogen sensor is a thermal sensor, its main functional area is at the position of the first working resistor 10 and the second working resistor 20, and it is required that the other parts do not generate heat as much as possible. According to the formula W = I 2 R, the smaller the resistance of each lead part (that is, the wider the lead line width), the smaller the heat generation and the smaller the impact on the sensor performance. Therefore, by increasing the width of each lead away from its corresponding resistor, the high performance of the sensor can be effectively guaranteed.

[0058] In addition, considering that the width of the lead is large and the width of the resistor is relatively small, the width of each lead close to its corresponding resistor is set to a size gradient structure. On the one hand, it can make the current gradually change, which is beneficial to the stability of the electrical performance of the sensor; on the other hand, it can ensure beautiful appearance.

[0059] Those skilled in the art can set the materials of each component according to actual needs, as long as the resistivity, temperature coefficient of resistivity, stability, conductivity, etc. meet the requirements, for example, platinum, aluminum, gold, etc. Preferably, the material of each lead is set to platinum, which has a higher temperature coefficient of resistivity and thermal stability; at the same time, platinum can be used to make the heating resistor 30, the first working resistor 10 and each lead at one time, saving costs and improving production efficiency. Preferably, the material of each pad is set to gold.

[0060] Reference Figure 1 , Figure 2 and Figure 3 As shown, in some embodiments of the hydrogen sensor of the present invention, two first working resistors 10 are symmetrically arranged about a first symmetry axis, and two second working resistors 20 are symmetrically arranged about the first symmetry axis, and the first symmetry axis is parallel to the first direction D1. The first component and the second component are symmetrically arranged about the second symmetry axis, and the second symmetry axis is parallel to the second direction D2. The first symmetry axis and the second symmetry axis are not shown in the figure.

[0061] Preferably, each component is arranged on a substrate 40 , and the substrate 40 is arranged as a rectangular parallelepiped structure, the first direction D1 is parallel to the length direction of the substrate 40 , the second direction D2 is parallel to the width direction of the substrate 40 , and the second symmetry axis and the first symmetry axis intersect at the center of the substrate 40 .

[0062] Preferably, for each first working resistor 10 in the first component, its corresponding first electrode 111 and second electrode 131 are arranged on the same side of the first symmetry axis. For each second working resistor 20 in the second component, its corresponding third electrode 211 and fourth electrode 231 are arranged on the same side of the first symmetry axis. The four electrodes located on the same side of the first symmetry axis are arranged in sequence along the first direction D1.

[0063] In the process of sensor tape-out and packaging, various errors and stresses will inevitably occur, affecting the performance of the sensor. By symmetrically setting the same functional structure, the degree of influence can be made consistent, so that most of the errors and stresses can be eliminated through the differential method in the future, ensuring the consistency of the finished product and the stability of the function.

[0064] It should be noted that since the components such as resistors, electrodes, and pads are all axisymmetric, in order to simplify the pattern and facilitate identification, the corresponding components are Figure 3 Only half of it was drawn.

[0065] Reference Figure 6 and Figure 7As shown, in some embodiments of the hydrogen sensor described in the present invention, the first working resistor 10 includes at least one first bending portion 101 and at least one second bending portion 102. The bending directions of the first bending portion 101 and the second bending portion 102 are opposite, and the first bending portion 101 and the second bending portion 102 are alternately arranged in sequence. Those skilled in the art can set the specific number of the two bending portions according to actual needs. In the figure, one of the two bending portions is set, and separated by dotted lines for illustration. By setting the first working resistor 10 with a serpentine bending structure, it is convenient for it to transfer heat evenly, and the space utilization rate and sensor stability are improved.

[0066] Reference Figure 6 and Figure 7 As shown, in some embodiments of the hydrogen sensor of the present invention, the second working resistor 20 includes at least one third bend 201 and at least one fourth bend 202. The bending directions of the third bend 201 and the fourth bend 202 are opposite, and the third bend 201 and the fourth bend 202 are alternately arranged in sequence. Those skilled in the art can set the specific number of the two bends according to actual needs. In the figure, one of the two bends is set, and separated by dotted lines for illustration. By setting the second working resistor 20 of the serpentine bending structure, not only the volume of the second working resistor 20 can be reduced, but also the surface area of ​​hydrogen adsorption can be increased to improve the sensitivity and accuracy of the detection, so that the sensor meets the needs of hydrogen detection in different application scenarios. Preferably, the first working resistor 10 and the second working resistor 20 are both set to a serpentine bending structure to achieve the best effect.

[0067] Reference Figure 1 , Figure 2 and Figure 8 As shown, in some embodiments of the hydrogen sensor of the present invention, the heating resistor 30 includes at least one fifth bend 301 and at least one sixth bend 302, the bending directions of the fifth bend 301 and the sixth bend 302 are opposite, and the fifth bend 301 and the sixth bend 302 are alternately arranged in sequence. Those skilled in the art can set the specific number of the two bends according to actual needs. In the figure, both bends are provided with multiple ones, and are separated by dotted lines for illustration. By setting the heating resistor 30 with the serpentine bending structure, the heat generating part can be distributed more evenly, so that the heated second working resistor 20 is evenly heated, so as to improve the sensitivity and stability of the sensor and ensure the reliability and accuracy of hydrogen leakage monitoring.

[0068] Furthermore, in some embodiments of the hydrogen sensor of the present invention, the third component further includes a fifth lead 32 , a fifth electrode 311 , a fifth pad 312 , a sixth lead 34 , a sixth electrode 331 and a sixth pad 332 .

[0069] Reference Figure 8 As shown, one end of the fifth lead 32 is electrically connected to one end of the heating resistor 30, the other end of the fifth lead 32 is electrically connected to the fifth electrode 311, and the fifth pad 312 is covered and electrically connected to the fifth electrode 311. The width of at least part of the fifth lead 32 gradually decreases from one end thereof to the end connected to the heating resistor 30. Preferably, the fifth lead 32 is arranged in an isosceles trapezoidal structure.

[0070] One end of the sixth lead 34 is electrically connected to the other end of the heating resistor 30, and the other end of the sixth lead 34 is electrically connected to the sixth electrode 331. The sixth pad 332 is covered and arranged on the sixth electrode 331 and electrically connected thereto. The width of at least part of the sixth lead 34 gradually decreases from one end thereof to the end connected to the heating resistor 30. Preferably, the sixth lead 34 is arranged in an isosceles trapezoidal structure. By setting this structure, the high performance and stability of the sensor can be ensured, and the shape is also made more beautiful.

[0071] Preferably, the materials of the leads, electrodes and pads in the third component are the same as those of other components and will not be described in detail.

[0072] Preferably, the fifth electrode 311 and the sixth electrode 331 are respectively arranged on both sides of the heating resistor 30 along the second direction D2, and the fifth electrode 311 and the sixth electrode 331 are both arranged between the corresponding third electrode 211 and the fourth electrode 231. By setting a symmetrical structure, the consistency of the finished product and the stability of the function can be ensured, and the components can be prepared simultaneously to improve the production efficiency.

[0073] Reference Figure 1 , Figure 2 and Figure 3 As shown, the hydrogen sensor described in the present invention, in some embodiments, further includes a substrate 40 and a membrane layer assembly 43 .

[0074] Preferably, the material of the substrate 40 is set to silicon. The substrate 40 includes a first plane 41 and a second plane 42 arranged opposite to each other along a third direction D3. Preferably, the third direction D3 is parallel to the thickness direction of the substrate 40. An insulating groove 411 is provided on the first plane 41 and extends to the second plane 42. The membrane layer assembly 43 is covered and arranged on the first plane 41. The membrane layer assembly 43 has an insulating area 431 corresponding to the insulating groove 411 to maintain the temperature of the resistor and prevent the temperature of each resistor from being conducted through the substrate 40.

[0075] Specifically, the film layer assembly 43 includes a first film layer 432 and a second film layer 433. The first film layer 432 is covered and arranged on the first plane 41, and the first film layer 432 is mainly used to carry the first working resistor 10, the heating resistor 30, each lead and the electrode. The first working resistor 10 and the heating resistor 30 are both arranged in the insulation area 431. Those skilled in the art can set the first film layer 432 to a silicon oxide film, or a silicon nitride film, or a composite film layer composed of a silicon oxide film and a silicon nitride film according to requirements. Preferably, the first film layer 432 includes a silicon oxide film and a silicon nitride film deposited in sequence.

[0076] The second film layer 433 is arranged to cover the first working resistor 10, the heating resistor 30, the leads and the electrodes to isolate the influence of humidity on the components. At the same time, it can prevent the components from reacting with hydrogen other than heat conduction to prevent interference with detection. Those skilled in the art can set the second film layer 433 as required; preferably, the second film layer 433 is set as a silicon oxide film. The second working resistor 20 is arranged on the second film layer 433.

[0077] Reference Figure 3 As shown, in some embodiments of the hydrogen sensor of the present invention, a ventilation cavity 421 is provided on the second plane 42, and the ventilation cavity 421 is connected to the thermal insulation groove 411. By providing the ventilation cavity 421, the gas in the thermal insulation groove 411 is facilitated to circulate, and the air in the groove is prevented from damaging the composite film layer under the action of thermal expansion, causing device failure. Preferably, the ventilation cavity 421 extends along the first direction D1, so that the hydrogen can take away more heat when flowing along the ventilation cavity 421, thereby improving the sensitivity and response speed of the sensor.

[0078] The present invention discloses a method for preparing a hydrogen sensor, which is used to prepare a hydrogen sensor as described in any one of the above embodiments. The preparation method comprises the following steps:

[0079] S1 . Depositing a first film layer 432 on a first plane 41 of a substrate 40 .

[0080] Preferably, the first film layer 432 includes a silicon oxide film and a silicon nitride film deposited in sequence. During preparation, a dense silicon oxide film is first deposited on the first plane 41 by thermal oxidation / plasma enhanced vapor deposition / low pressure vapor deposition, and its thickness is set to 30 to 1500nm; then, a prestressed silicon nitride film is deposited on the silicon oxide film by plasma enhanced vapor deposition / low pressure vapor deposition, and its thickness is set to 30 to 1000nm, so as to set the corresponding components.

[0081] S2. Form a first working resistor 10, a heating resistor 30, leads and electrodes on the first film layer 432.

[0082] Preferably, platinum is made by evaporation / sputtering, stripping / etching to form the first working resistor 10, the heating resistor 30, each lead and each electrode, and the thickness thereof is set to 100 to 300 nm.

[0083] S3. Form a second film layer 433 on the first film layer 432, wherein the second film layer 433 covers the first working resistor 10, the heating resistor 30 and the lead wire.

[0084] Preferably, the second film layer 433 is a silicon oxide film. During preparation, a silicon oxide film with prestress is first formed by plasma enhanced vapor deposition / low pressure vapor deposition, and its thickness is set to 30 to 1000 nm. Subsequently, the silicon oxide film is etched to expose each electrode.

[0085] S4 , forming a second working resistor 20 on the second film layer 433 .

[0086] Preferably, the palladium alloy is made by evaporation / sputtering and stripping / etching to form the second working resistor 20, and the thickness thereof is set to be 100 to 300 nm.

[0087] S5. Form a pad on the electrode.

[0088] Preferably, gold is made on each electrode by evaporation / sputtering, stripping / etching to form each pad, and the thickness of the pad is set to 100 to 300 nm.

[0089] S6 , etching a ventilation cavity 421 on the second plane 42 of the substrate 40 .

[0090] Preferably, the ventilation cavity 421 is etched by a dry / wet etching process.

[0091] S7. Etching the thermal insulation groove 411 on the ventilation cavity 421 to obtain a hydrogen sensor.

[0092] Preferably, the thermal insulation groove 411 is etched by a dry / wet etching process.

[0093] Obviously, the above embodiments are merely examples for clear explanation and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from these are still within the protection scope of the invention.

Claims

1. A hydrogen sensor, characterized in that: include: A first component, the first component includes two first working resistors, and the first working resistors are metal thermal resistors; A second component, wherein the second component includes two second working resistors, and the second working resistors are palladium alloy thin film resistors; as well as A third component, the third component includes a heating resistor, the heating resistor is used to heat the second working resistor to a working temperature, and the two second working resistors are both arranged in a heating area of ​​the heating resistor; Wherein, the hydrogen sensor is configured to be able to switch between a first mode, a second mode, a third mode and a fourth mode; when in the first mode, one of the first working resistors and one of the second working resistors are connected in series to form a detection unit, and the two detection units are connected in parallel to work; when in the second mode, one of the detection units works; when in the third mode, the two first working resistors work in a time-sharing manner; when in the fourth mode, the two second working resistors work in a time-sharing manner.

2. The hydrogen sensor according to claim 1, characterized in that: When no power is supplied and no hydrogen is supplied, the resistance of the first working resistor is R1, and the resistance of the second working resistor is R2; when power is supplied and hydrogen is supplied, the resistance of the first working resistor is R1-ΔR1, and the resistance of the second working resistor is R2+ΔR2. The first working resistor and the second working resistor are selected so that the sensitivity in the first mode and the second mode is maximum.

3. The hydrogen sensor according to claim 1, characterized in that: The first component further includes a first lead, a first electrode, a first pad, a second lead, a second electrode, and a second pad; one end of the first lead is electrically connected to one end of the first working resistor, the other end of the first lead is electrically connected to the first electrode, the first pad is covered and arranged on the first electrode and is electrically connected thereto, wherein the width of at least part of the first lead gradually decreases from one end thereof to the end connected to the first working resistor; one end of the second lead is electrically connected to the other end of the first working resistor, the other end of the second lead is electrically connected to the second electrode, the second pad is covered and arranged on the second electrode and is electrically connected thereto, wherein the width of at least part of the second lead gradually decreases from one end thereof to the end connected to the first working resistor; The second component also includes a third lead, a third electrode, a third pad, a fourth lead, a fourth electrode and a fourth pad, one end of the third lead is electrically connected to one end of the second working resistor, the other end of the third lead is electrically connected to the third electrode, the third pad is covered on the third electrode and electrically connected thereto, wherein the width of at least part of the third lead gradually decreases from one end thereof to the end connected to the second working resistor; one end of the fourth lead is electrically connected to the other end of the second working resistor, the other end of the fourth lead is electrically connected to the fourth electrode, the fourth pad is covered on the fourth electrode and electrically connected thereto, wherein the width of at least part of the fourth lead gradually decreases from one end thereof to the end connected to the second working resistor.

4. The hydrogen sensor according to any one of claims 1 to 3, characterized in that: The two first working resistors are symmetrically arranged about a first symmetry axis, the two second working resistors are symmetrically arranged about the first symmetry axis, and the first symmetry axis is parallel to a first direction; the first component and the second component are symmetrically arranged about a second symmetry axis, and the second symmetry axis is parallel to a second direction.

5. The hydrogen sensor according to any one of claims 1 to 3, characterized in that: The first working resistor comprises at least one first bending portion and at least one second bending portion, the bending directions of the first bending portion and the second bending portion are opposite, and the first bending portion and the second bending portion are alternately arranged in sequence; or / and The second working resistor includes at least one third bending portion and at least one fourth bending portion, the third bending portion and the fourth bending portion have opposite bending directions, and the third bending portion and the fourth bending portion are alternately arranged in sequence.

6. The hydrogen sensor according to any one of claims 1 to 3, characterized in that: The heating resistor includes at least one fifth bending portion and at least one sixth bending portion, the bending directions of the fifth bending portion and the sixth bending portion are opposite, and the fifth bending portion and the sixth bending portion are alternately arranged in sequence.

7. The hydrogen sensor according to claim 6, characterized in that: The third component also includes a fifth lead, a fifth electrode, a fifth solder pad, a sixth lead, a sixth electrode and a sixth solder pad; one end of the fifth lead is electrically connected to one end of the heating resistor, the other end of the fifth lead is electrically connected to the fifth electrode, the fifth solder pad is covered on the fifth electrode and electrically connected thereto, wherein the width of at least part of the fifth lead gradually decreases from one end thereof to the end connected to the heating resistor; one end of the sixth lead is electrically connected to the other end of the heating resistor, the other end of the sixth lead is electrically connected to the sixth electrode, the sixth solder pad is covered on the sixth electrode and electrically connected thereto, wherein the width of at least part of the sixth lead gradually decreases from one end thereof to the end connected to the heating resistor.

8. The hydrogen sensor according to any one of claims 1 to 3, characterized in that: Also includes: A substrate, the substrate comprising a first plane and a second plane arranged opposite to each other along a third direction, wherein a heat-insulating groove is formed on the first plane and extends through the second plane; as well as A membrane layer assembly, wherein the membrane layer assembly has an insulating area corresponding to the insulating groove, the membrane layer assembly includes a first membrane layer and a second membrane layer, the first membrane layer is covered and arranged on the first plane, the first working resistor and the heating resistor are arranged above the first membrane layer, and the first working resistor and the heating resistor are both arranged in the insulating area, the second membrane layer is covered and arranged above the first working resistor and the heating resistor, and the second working resistor is arranged above the second membrane layer.

9. The hydrogen sensor according to claim 8, characterized in that: A ventilation cavity is provided on the second plane, the ventilation cavity extends along the first direction, and the ventilation cavity is communicated with the thermal insulation groove.

10. A method for preparing a hydrogen sensor, used for preparing the hydrogen sensor as claimed in any one of claims 1 to 9, characterized in that: The following steps are involved: S1, depositing a first film layer on a first plane of a substrate; S2, forming a first working resistor, a heating resistor, a lead and an electrode on the first film layer; S3, forming a second film layer on the first film layer, wherein the second film layer covers the first working resistor, the heating resistor and the lead wire; S4, forming a second working resistor on the second film layer; S5, forming a pad on the electrode; S6, etching a ventilation cavity on a second plane of the substrate, wherein the second plane is arranged opposite to the first plane; S7, etching a thermal insulation groove on the ventilation cavity to obtain a hydrogen sensor.

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