A method for manufacturing a humidity sensor chip

Abstract

The application relates to a manufacturing method of a humidity sensor chip, which aims to realize a wide humidity measurement range and greatly reduce manufacturing process complexity and manufacturing cost. The technical scheme is as follows: a resistance type humidity sensitive material is used to realize the manufacturing of the humidity sensor, the humidity sensitive material is deposited on a substrate, and the substrate is provided with interdigital electrodes. In the direction from the first edge to the second edge of the substrate, the distribution density of the deposited first humidity sensitive material gradually decreases, the distribution density of the deposited second humidity sensitive material on the substrate gradually increases, and the humidity sensitive material composition continuously changes. The selected first humidity sensitive material and the second humidity sensitive material have different humidity sensitive characteristic curves and different optimal humidity sensing ranges. The greater the difference between the optimal humidity sensing ranges of the two humidity sensitive materials, the wider the humidity measurement range of the final humidity sensor obtained by the application.

Description

TECHNICAL FIELD

[0001] The present application relates to a manufacturing method of a humidity sensor chip. BACKGROUND

[0002] The humidity-sensitive resistor is characterized by covering a film made of humidity-sensitive material on a substrate, and when water vapor in the air is adsorbed on the humidity-sensitive film, the resistivity and resistance value of the element change, and the humidity can be measured by using this characteristic. The humidity-sensitive resistor has the advantages of high sensitivity, but the disadvantages of poor linearity and interchangeability of products. There are many types of humidity-sensitive resistors, such as metal oxide humidity-sensitive resistors, silicon humidity-sensitive resistors, ceramic humidity-sensitive resistors, and organic humidity-sensitive resistors.

[0003] The prepared humidity sensor product using a specific humidity-sensitive material is often only suitable for measuring a specific humidity range, and can only have good accuracy within a certain humidity range. When the measurement range is exceeded, the accuracy becomes extremely unreliable. In order to realize a wide humidity measurement range, humidity sensors with different humidity measurement ranges are usually used in parallel, so that the overall humidity sensor system can cover the humidity measurement range of each sub-humidity sensor. However, this approach has the problems of high cost and complex manufacturing process, and it is difficult to balance the wide humidity measurement range and low cost and manufacturing complexity. This is really a headache. SUMMARY

[0004] In order to solve the above technical problems, the present application provides a manufacturing method of a humidity sensor chip, which aims to realize a wide humidity measurement range and greatly reduce the manufacturing process complexity and manufacturing cost.

[0005] The technical solution is to use a resistance type humidity-sensitive material to realize the manufacturing of a humidity sensor, the humidity-sensitive material is deposited on a substrate, and the substrate has interdigital electrodes, and the signals collected by the interdigital electrodes can be used to obtain the environmental humidity signal.

[0006] The humidity sensor chip includes a rectangular substrate having a first edge and a second edge arranged opposite to each other, a third edge and a fourth edge arranged opposite to each other, and the manufacturing method of the humidity sensor chip includes the following steps:

[0007] A. Preparing a pair of interdigital electrodes on the rectangular substrate;

[0008] B. Preparing humidity-sensitive material on the rectangular substrate with a pair of interdigital electrodes obtained in step A, and the specific implementation is as follows:

[0009] B-a. Pulsed atomization spraying the first humidity sensitive material to the rectangular substrate from above the first edge, obliquely downward to the second edge of the rectangular substrate, the aerosol containing the first humidity sensitive material has a concentration gradient, so that the distribution density of the first humidity sensitive material deposited on the substrate gradually decreases from the first edge to the second edge;

[0010] B-b. Pulsed atomization spraying the second humidity sensitive material to the rectangular substrate from above the second edge, obliquely downward to the first edge of the rectangular substrate, the aerosol containing the second humidity sensitive material has a concentration gradient, so that the distribution density of the second humidity sensitive material deposited on the substrate gradually decreases from the second edge to the first edge;

[0011] Steps B-a and B-b are alternately performed, and the number of repetitions is determined according to the needs;

[0012] C. Drying and curing the humidity sensitive material;

[0013] D. Soldering the electrode lead wire, and completing the manufacture of the humidity sensor chip.

[0014] The first humidity sensitive material and the second humidity sensitive material have different surface resistivity-humidity characteristic curves, so that the first humidity sensitive material and the second humidity sensitive material have different optimal humidity sensing sensitivities.

[0015] The composite humidity sensitive material formed by the first humidity sensitive material and the second humidity sensitive material after steps B-a and B-b are alternately performed several times from the first edge to the second edge has a surface resistivity-humidity characteristic curve that gradually changes in the length direction of the electrode, so that the composite humidity sensitive material at different positions has different optimal humidity sensing sensitivities; and a wide-range resistance type humidity sensor is finally obtained.

[0016] The first humidity sensitive material and the second humidity sensitive material are both nanomaterials, and each is uniformly dispersed in a solvent to form a solution for pulsed atomization spraying.

[0017] In the length direction of the electrode, the resistivity-humidity characteristic curve of the humidity sensitive material presents gradual change, and the humidity sensitive materials at different positions respond to different ambient humidity, which is realized by the composition and / or specific surface area and / or nanoscale size and / or microstructure of the humidity sensitive materials at different positions. For example, in the length direction of the electrode, the composition of the humidity sensitive material is gradually changed, so that the composition of the humidity sensitive material at different positions is different, which brings about the gradual change of the resistivity-humidity characteristic curve of the humidity sensitive material. The humidity sensitive materials at different positions each respond to a different humidity change range, which means that each has its own function. The gradual change of the resistivity-humidity characteristic curve of the humidity sensitive material can enable the humidity sensitive resistance between a pair of electrodes to respond sensitively to a wide range of humidity changes.

[0018] The technical solution of the present application is a further development based on our prior application CN202111158676X "resistance type humidity sensor with wide measurement range". The technical principle can be referred to in the prior application CN202111158676X, and will not be repeated in this patent application. The content in the description of the prior application CN202111158676X can be regarded as part of the present patent, and the applicant reserves the right to introduce, add part or all of the content in the description of CN202111158676X if necessary.

[0019] Humidity sensitive materials with different compositions, different micro-nano structures, and different specific surface area materials will all exhibit different optimal humidity sensing ranges. The specific sensing range can be reasonably selected according to the actual situation.

[0020] Through the above arrangement, the same humidity sensor can respond to a wide range of humidity changes, thereby realizing a wide measurement range of humidity. As can be seen from the core idea of the present application, the present application provides a resistance type humidity sensor with a wide measurement range, which realizes a wide humidity measurement range while maintaining accuracy, and can further reduce manufacturing cost and complexity of the humidity sensor. Thus, the inventor has described the working principle, technical solution and technical effect of the present application in detail. Those aspects of the description which are not otherwise fully described are deemed to be part of the prior art to those skilled in the art . BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 A humidity sensor chip in the present application.

[0022] In the figure: 1 is the first edge, 2 is the second edge, 3 is the third edge, and 4 is the fourth edge. DETAILED DESCRIPTION

[0023] The technical solution of the present application will be described in detail below with examples.

[0024] As Figure 1 shown, the humidity sensor chip of the present application comprises humidity sensitive material, rectangular substrate, a pair of interdigital electrodes; a pair of interdigital electrodes, humidity sensitive material are prepared on the substrate. The rectangular substrate has oppositely arranged first edge 1 and second edge 2, oppositely arranged third edge 3 and fourth edge 4. The pair of interdigital electrodes includes first sub-electrode and second sub-electrode, the spacing between the lead strip of the first sub-electrode and the lead strip of the second sub-electrode is L, the line spacing between the first sub-electrode and the second sub-electrode is w, and the vertical distance between any point and the lead strip of the first sub-electrode is x.

[0025] The manufacturing method of the humidity sensor chip comprises the following steps:

[0026] A. Prepare a pair of interdigital electrodes on the rectangular substrate;

[0027] In specific implementation, in step A, any one of the processes of sputtering, evaporation, mask printing, chemical plating and screen printing is used to complete the preparation of the interdigital electrodes;

[0028] B. Prepare humidity sensitive material on the rectangular substrate obtained in step A which is attached with a pair of interdigital electrodes, and the specific implementation is as follows:

[0029] B-a. Use an atomizing nozzle to direct from above the first edge 1 obliquely downward to the second edge 2 of the rectangular substrate, and pulse atomizing spray the first humidity sensitive material to the rectangular substrate, the gas mist containing the first humidity sensitive material has a concentration gradient, so that the distribution density of the first humidity sensitive material deposited on the substrate gradually decreases from the first edge 1 to the second edge 2;

[0030] B-b. Use an atomizing nozzle to direct from above the second edge 2 obliquely downward to the first edge 1 of the rectangular substrate, and pulse atomizing spray the second humidity sensitive material to the rectangular substrate, the gas mist containing the second humidity sensitive material has a concentration gradient, so that the distribution density of the second humidity sensitive material deposited on the substrate gradually decreases from the second edge 2 to the first edge 1;

[0031] Steps B-a and B-b are alternately performed, and the number of repetitions is determined according to the needs;

[0032] C. Dry and cure the humidity sensitive material;

[0033] D. Weld the electrode lead, complete the manufacturing of the humidity sensor chip.

[0034] The electrode and the humidity sensitive material are attached on the rectangular substrate. In step A, the interdigital lines of the interdigital electrode are parallel to the third edge 3 and the fourth edge 4 of the substrate, and the two lead lines of the interdigital electrode are parallel to the first edge 1 and the second edge 2 of the substrate, and are close to the first edge 1 and the second edge 2 of the substrate respectively, and the two lead lines are respectively provided with lead pads. Figure 1 The square area on the two sub-electrodes in the above formula is the lead pad.

[0035] Preferably, the first humidity sensitive material and the second humidity sensitive material are both nanomaterials, and are uniformly dispersed in a solvent to form a solution for pulse atomization spraying.

[0036] The first humidity sensitive material and the second humidity sensitive material are characterized by having water absorption properties, and the change of the resistivity with the water content caused by the absorption of moisture in the ambient air. The first humidity sensitive material and the second humidity sensitive material can be organic composite materials, inorganic composite materials, or organic / inorganic composite materials. The resistivity of the first humidity sensitive material and the second humidity sensitive material changes with the change of humidity.

[0037] For example, the first humidity sensitive material and the second humidity sensitive material are selected from any two of SnO2 nanomaterial, Fe3O4 nanomaterial, Sb2O3 nanomaterial, ZnO nanomaterial, In2O3 nanomaterial, TiO2 nanowire, PdCl2 nanomaterial, Cu2O nanomaterial, WO3 nanomaterial, CeO2 nanomaterial, MnWO4 powder, NiWO4 powder, ZnCrO4 powder, MgCr2O4 powder, polypyrrole, polyethylene dioxythiophene, polystyrene sulfonate, methyl methacrylate dimethylaminoethyl bromide n-butane quaternary ammonium salt (MEBA), and active siloxane monomer γ-methacryloyl propyl trimethoxysilane (KH570).

[0038] The humidity sensitive material can also be selected from any other known material with humidity sensitivity. It is only required that the selected first humidity sensitive material and the second humidity sensitive material have different humidity sensitive characteristics curves, that is, have different optimal humidity sensing ranges. The greater the difference between the optimal humidity sensing ranges of the two humidity sensitive materials, the wider the humidity measurement range of the final humidity sensor obtained by the present application.

[0039] In the direction from the first edge 1 to the second edge 2, the composite humidity sensitive material obtained by the first humidity sensitive material and the second humidity sensitive material after step B-a and B-b are alternately performed several times has a surface resistivity-humidity characteristic curve that gradually changes in the length direction of the electrode, so that the composite humidity sensitive material at different positions has different optimal humidity sensing sensitivities; and finally a wide measurement range resistance type humidity sensor is obtained.

[0040] Steps Ba and Bb are performed alternately, with the atomizing nozzle moving above the first edge 1 and the second edge 2, respectively, and the spraying direction pointing obliquely downwards towards the second edge 2 and the first edge 1 of the rectangular substrate; each pulse atomizing spray is switched by a micro-valve to deliver either the solution of the first humidity-sensitive material or the solution of the second humidity-sensitive material to the atomizing nozzle.

[0041] like Figure 1 As shown, point Surface resistivity-humidity function of humidity-sensitive materials The partial derivative of surface resistivity with humidity Let x represent the humidity sensitivity of the surface resistivity at point x as a function of humidity. This represents the function curve showing the relationship between the humidity sensitivity of a humidity-sensitive material and the humidity h. The peak value of the function curve represents the optimal humidity sensitivity of the humidity-sensitive material at point x. Therefore: from the near end to the far end, the humidity-sensitive material... The peak value of the function curve varies with Gradually moving; in the above formula R Indicates the surface resistivity of humidity-sensitive materials. Indicates humidity.

[0042] A pair of interdigitated electrodes includes a first sub-electrode and a second sub-electrode. The distance between the lead lines of the first sub-electrode and the lead lines of the second sub-electrode is L, and the line spacing between the first sub-electrode and the second sub-electrode is w. At any point between the lead lines of the first sub-electrode and the second sub-electrode, at a perpendicular distance x from the lead line of the first sub-electrode, the surface resistivity R of the composite humidity-sensitive material is a function of humidity h and distance x. If the resistance of the humidity-sensitive material at any point x of the first and second sub-electrodes is regarded as Rx, then the total resistance between a pair of interdigitated electrodes is equivalent to the parallel connection of humidity-sensitive resistors at countless locations.

[0043] As the distribution density of the first humidity-sensitive material deposited on the substrate gradually decreases from the first edge 1 to the second edge 2, and the distribution density of the second humidity-sensitive material deposited on the substrate gradually increases, the composition of the humidity-sensitive material undergoes continuous change. The total parallel resistance can be expressed in integral form:

[0044] The total resistance between a pair of interdigital electrodes is .

[0045] Through the above setting, the same humidity sensor can respond to a wide humidity change range, and then a wide humidity measurement range is realized. It can be seen that the manufacturing method of the wide measurement range resistance type humidity sensor is provided, the wide humidity measurement range is realized while the accuracy is maintained, and the manufacturing cost and the complexity of the humidity sensor can be further reduced.

[0046] The above merely provides the preferred embodiment of the present application, but the protection scope of the present application is not limited to this. Any change or replacement within the technical range disclosed by the present application can be easily thought by those skilled in the art, and should be covered within the protection scope of the present application. The contents not described in detail in the specification belong to the prior art known by those skilled in the art.

Claims

1. A method of manufacturing a humidity sensor chip, characterized by: The humidity sensor chip comprises a rectangular substrate with a first edge and a second edge arranged oppositely, a third edge and a fourth edge arranged oppositely, and a manufacturing method of the humidity sensor chip comprises the following steps: A. Preparing a pair of interdigital electrodes on the rectangular substrate; B. Preparing humidity sensitive materials on the rectangular substrate with the pair of interdigital electrodes obtained in step A, and the preparation is implemented as follows: B-a. Using an atomizing nozzle to pulse atomize the first humidity sensitive material to the rectangular substrate from above the first edge obliquely downward to the second edge of the rectangular substrate, and the aerosol containing the first humidity sensitive material has a concentration gradient, so that the distribution density of the first humidity sensitive material deposited on the substrate gradually decreases from the first edge to the second edge; B-b. Using an atomizing nozzle to pulse atomize the second humidity sensitive material to the rectangular substrate from above the second edge obliquely downward to the first edge of the rectangular substrate, and the aerosol containing the second humidity sensitive material has a concentration gradient, so that the distribution density of the second humidity sensitive material deposited on the substrate gradually decreases from the second edge to the first edge; steps B-a and B-b are alternately performed, and the number of repetitions is determined according to requirements; C. Drying and curing the humidity sensitive materials; D. Welding electrode lead wires to complete the manufacturing of the humidity sensor chip; The rectangular substrate is attached with electrodes and humidity sensitive materials, in step A, the interdigital lines of the interdigital electrodes are located between the third edge and the fourth edge of the substrate and are parallel to the third edge and the fourth edge of the substrate, the two lead lines of the pair of interdigital electrodes are parallel to the first edge and the second edge of the substrate and are respectively close to the first edge and the second edge of the substrate, and the two lead lines are respectively provided with lead pads; the first humidity sensitive material and the second humidity sensitive material have different surface resistivity-humidity characteristic curves, so that the first humidity sensitive material and the second humidity sensitive material have different optimal humidity sensing sensitivities.

2. The method of claim 1, wherein: In step A, any one of sputtering, evaporation, mask printing, chemical plating and screen printing is used to complete the preparation of the interdigital electrodes.

3. The method of claim 1 or 2, characterized in that: The first humidity sensitive material and the second humidity sensitive material are both nanomaterials, and each is uniformly dispersed in a solvent to form a solution for pulse atomization.

4. The method of claim 1 or 2, wherein: From the first edge to the second edge, the first humidity sensitive material and the second humidity sensitive material obtained after steps B-a and B-b are alternately performed for several times form a composite humidity sensitive material, and the surface resistivity-humidity characteristic curve of the composite humidity sensitive material gradually changes in the length direction of the electrode, so that the composite humidity sensitive material at different positions has different optimal humidity sensing sensitivities; and finally a wide-range resistance type humidity sensor is obtained.

5. The method of claim 1 or 2, wherein: Steps B-a and B-b are alternately performed, the atomizing nozzle is moved to above the first edge and above the second edge respectively, and the angle is adjusted, and the spraying directions are obliquely downward to the second edge and the first edge of the rectangular substrate respectively.

6. The method of claim 1 or 2, wherein: The pair of interdigital electrodes comprises a first sub-electrode and a second sub-electrode, the spacing between the lead-out lines of the first sub-electrode and the lead-out lines of the second sub-electrode is L, the line spacing between the first sub-electrode and the second sub-electrode is w, and the surface resistivity R of the composite humidity-sensitive material at any point between the lead-out lines of the first sub-electrode and the second sub-electrode and at a vertical distance x from the lead-out lines of the first sub-electrode is a function of humidity h and distance x, R(h, x).

7. The method of claim 1 or 2, wherein: Each pulsed atomization injection is switched by a micro valve to deliver the solution of the first humidity-sensitive material or the solution of the second humidity-sensitive material to the atomization nozzle.

8. The method of claim 1 or 2, wherein: The first humidity-sensitive material and the second humidity-sensitive material are selected from any two of SnO2 nanomaterials, Fe3O4 nanomaterials, Sb2O3 nanomaterials, ZnO nanomaterials, In2O3 nanomaterials, TiO2 nanowires, PdCl2 nanomaterials, Cu2O nanomaterials, WO3 nanomaterials, CeO2 nanomaterials, MnWO4 powder, NiWO4 powder, ZnCrO4 powder, MgCr2O4 powder, polypyrrole, polyethylene dioxythiophene, sodium polystyrene sulfonate, dimethylaminoethyl methacrylate bromine n-butane quaternary ammonium salt, and active siloxane monomer γ-methacryloylpropyl trimethoxysilane; the humidity-sensitive material is selected from any other known material with humidity-sensitive properties, and the selected first humidity-sensitive material and second humidity-sensitive material have different humidity-sensitive characteristic curves.

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