A method for preparing an insulating isolation layer of a temperature sensor

Abstract

The invention discloses a method for preparing an insulating isolation layer of a temperature sensor, and relates to the technical field of electronic insulating materials. The preparation method includes the following steps: depositing a platinum resistance layer on an aluminum oxide substrate; etching the platinum resistance layer into a desired pattern; annealing the etched pattern in air to make the pattern layer dense; performing laser resistance adjustment; preparing an insulating isolation layer slurry, and coating the insulating isolation layer slurry on the substrate by immersion and pulling; after the insulating isolation layer slurry is coated, sintering is performed in air. The insulating isolation layer slurry is coated on the aluminum oxide substrate with the platinum resistance layer deposited by the immersion and pulling method. On the one hand, insulation protection of the aluminum oxide substrate with the platinum resistance layer deposited is achieved. On the other hand, the insulating isolation layer is coated by the immersion and pulling method, which will not produce radial growth orientation, and will not have pores and cracks. It has good stability and high preparation efficiency, and the thickness of the insulating isolation layer is controllable.

Description

Technical Field

[0001] The invention relates to the technical field of insulating materials, and in particular to a method for preparing an insulating isolation layer of a temperature sensor. Background Art

[0002] In temperature sensors, it is well known to provide an isolation layer to prevent poisoning of the resistor layer, for example, by coating an insulating isolation layer on the platinum pattern of the temperature sensor using PVD or thick film methods. However, the passivation layer coated in this way cannot completely prevent toxic contamination.

[0003] In the PVD method, the insulating isolation material, especially the aluminum oxide material (Al2O3), is converted into a gas phase and then condensed into a film on the surface of the resistor pattern. In this way, not only the phase state of the material is a disadvantage, but also the coating will undergo oriented growth. For example, the aluminum oxide used is in the γ phase, which is converted into a stable α phase during the heating process. The transformation from the γ phase to the α phase can cause a volume shrinkage of about 8%. At the same time, since the coating is radially oriented, this volume shrinkage will be aggravated to produce cracks in the coated insulating isolation, especially the connection between the lines and grooves of the pattern is prone to cracking.

[0004] In the thick film screen printing method, a paste containing aluminum oxide is printed on the surface of the resistor pattern. After the debinding process, the aluminum oxide is sintered at a temperature of 1000°C to 1500°C. Even if the particle size is adjusted to achieve a high solid content and high density paste, the aluminum oxide coating still contains pores and defects after sintering.

[0005] In order to seal the insulating isolation layer manufactured by the above method, it is known to additionally apply other layers, for example composed of glass, but heat-resistant glass has an extremely high silicon dioxide (SiO2) content, and silicon can diffuse into the resistor layer through pores and cracks, especially into the platinum resistor layer, to form platinum silicide, which can cause corrosion of the platinum resistor pattern layer, a change in resistance, and a reduction in accuracy. Summary of the invention

[0006] Based on the problems existing in the background technology, the purpose of the present invention is to provide a method for preparing an insulating isolation layer of a temperature sensor. The insulating isolation layer prepared by this method will not produce a radial growth orientation, and will not have pores and cracks. It has good stability and high preparation efficiency, and the thickness of the insulating isolation layer is controllable.

[0007] The present invention is achieved through the following technical solutions:

[0008] The present application provides a method for preparing an insulating isolation layer of a temperature sensor, comprising the following steps:

[0009] depositing a platinum resistance layer on an alumina substrate;

[0010] Etching the platinum resistance layer into a desired pattern;

[0011] Annealing the etched pattern in air to make the pattern layer dense;

[0012] Perform laser resistance trimming;

[0013] Prepare an insulating isolation layer slurry, and apply the insulating isolation layer slurry on the substrate by dipping and pulling;

[0014] After the insulating layer slurry is applied, it is sintered in air.

[0015] The method for preparing the insulating isolation layer is applicable to any device requiring insulation / isolation protection of the functional layer, and is particularly applicable to thin film devices.

[0016] The present invention adopts a dipping and pulling method to coat the insulating isolation layer slurry on the aluminum oxide substrate deposited with the platinum resistance layer. On the one hand, insulation protection of the aluminum oxide substrate deposited with the platinum resistance layer is achieved. On the other hand, the insulating isolation layer is coated by dipping and pulling, which does not produce radial growth orientation, pores and cracks, has good stability and high preparation efficiency, and the thickness of the insulating isolation layer is controllable.

[0017] Furthermore, the pulling speed during the immersion pulling coating of the insulating isolation layer slurry is 50 μm / s to 5000 μm / s.

[0018] The present invention controls the speed of immersion and pulling coating of the insulating isolation layer slurry to 50 μm / s to 5000 μm / s, which can make the insulating isolation layer slurry more evenly coated on the alumina substrate, and also facilitate the control of the thickness of the insulating isolation layer coated on the alumina substrate.

[0019] Furthermore, the number of dipping and pulling is at least one; when multiple dipping and pulling are required, the last dipping and pulling needs to be completely dried before the next dipping and pulling can be performed.

[0020] The number of dipping and pulling can be selected according to actual needs. When the insulating isolation layer to be coated is thicker, multiple dipping and pulling methods can be used; when the insulating isolation layer to be coated is thinner, a relatively small number of dipping and pulling methods can be used for coating.

[0021] After the last dip and pull, it needs to be completely dried before the next dip and pull can be carried out. On the one hand, it is to achieve the effect of layer-by-layer coating to facilitate the control of the thickness of the insulating isolation layer. On the other hand, it also avoids the insulating isolation film layer coated on the alumina substrate last time entering the slurry before it is firmly bonded to the alumina substrate, causing the previous insulating isolation film layer to fall off.

[0022] Furthermore, the drying temperature is 75°C to 300°C.

[0023] Furthermore, the drying time is 10min~2h.

[0024] By controlling the drying speed and using a nearly constant temperature method for drying, it is possible to prevent the solvent from volatilizing rapidly and in large quantities at a certain temperature, thereby preventing cracks from forming.

[0025] Furthermore, the sintering temperature in air is 1000°C to 1500°C.

[0026] Furthermore, the sintering time in air is 30 minutes to 5 hours.

[0027] Furthermore, the formula for preparing the insulating isolation layer slurry includes alumina sol, deionized water, and glycerol; the volume ratio of the alumina sol, deionized water, and glycerol is (10-17): (2-10): (1-5).

[0028] The insulating isolation layer slurry in the present application is simple to prepare, and the raw material components only need to be mixed evenly. At the same time, the formula is easy to obtain, and the insulating isolation layer slurry prepared by using the formula will not generate bubbles, has low surface tension, good spreadability, and will not cause coating condensation.

[0029] Furthermore, the alumina sol is modified by titanium dioxide, the addition amount of titanium dioxide is 2% to 5% of the mass of the alumina sol, and a binder is added during the modification process, the addition amount of the binder is 10% to 15% of the mass of the alumina sol.

[0030] The resistance performance of the insulating isolation layer depends on the content of impurity elements in the coating slurry. Generally speaking, the higher the purity of the coating, the better the resistance performance, but the porosity will also have a great influence on the resistance performance. In this application, the insulating isolation layer slurry is configured with alumina sol to which titanium dioxide is added and other components. After spraying, the coating has γ-alumina as the main crystal phase. On the one hand, the added titanium dioxide can reduce the volume resistivity of the coating. On the other hand, the added titanium dioxide can also reduce the melting point of the alumina sol, thereby making the coated insulating isolation layer denser and improving the insulating isolation effect.

[0031] Furthermore, the binder includes any one of polyvinylidene fluoride and polyimide or a combination of the two.

[0032] In the present application, by adding a binder, the density of the insulating isolation layer can be further improved. At the same time, the added polyvinylidene fluoride contains a strong polar group and has a strong anchoring ability for aluminum oxide, so that the aluminum oxide can be better dispersed in the insulating coating, and at the same time, it has a good adhesion ability to the substrate, which helps to improve the glass strength and insulation performance of the insulating isolation layer. In addition, the added polyimide contains an imide structure, which has a large rigidity, can improve the modulus of the insulating isolation layer, and ensure the mechanical strength of the insulating isolation layer without affecting the dispersibility of the insulating isolation layer.

[0033] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0034] (1) The present invention adopts a dipping and pulling method to coat the insulating isolation layer slurry on the aluminum oxide substrate on which the platinum resistance layer is deposited. On the one hand, the insulation protection of the aluminum oxide substrate on which the platinum resistance layer is deposited is achieved. On the other hand, the insulating isolation layer is coated by dipping and pulling, which does not produce radial growth orientation, pores and cracks, has good stability and high preparation efficiency, and the thickness of the insulating isolation layer is controllable;

[0035] (2) The present invention controls the speed of immersion and pulling the insulating isolation layer slurry to be coated within a range of 50 μm / s to 5000 μm / s. On the one hand, the insulating isolation layer slurry can be coated more evenly on the alumina substrate. On the other hand, it is also convenient to control the thickness of the insulating isolation layer coated on the alumina substrate.

[0036] (3) The present invention adopts a method in which the next dipping and pulling can only be carried out after complete drying after the last dipping and pulling. On the one hand, this is to achieve the effect of layer-by-layer coating and facilitate the control of the thickness of the insulating isolation layer. On the other hand, it also prevents the insulating isolation film layer coated on the alumina substrate from entering the slurry before being firmly bonded to the alumina substrate, causing the previous insulating isolation film layer to fall off;

[0037] (4) The present invention controls the drying speed and adopts a nearly constant temperature method to dry the product, thereby preventing the solvent from volatilizing rapidly and in large quantities at a certain temperature and causing cracks;

[0038] (5) The insulating isolation layer slurry in the present application is simple to prepare, and the raw material components only need to be mixed evenly. The formula is also easy to obtain. In addition, the insulating isolation layer slurry prepared by the formula does not generate bubbles, has low surface tension, good spreadability, and does not cause coating condensation.

[0039] (6) In the present application, the insulating isolation layer slurry is prepared by adding titanium dioxide to the alumina sol and other components. After impregnation, the coating has γ-alumina as the main crystal phase. On the one hand, the added titanium dioxide can reduce the volume resistivity of the coating. On the other hand, the added titanium dioxide can also reduce the melting point of the alumina sol, thereby making the coated insulating isolation layer denser and improving the insulating isolation effect.

[0040] (7) In the present application, the density of the insulating isolation layer can be further improved by adding a binder. At the same time, the added polyvinylidene fluoride contains a strong polar group and has a strong anchoring ability for aluminum oxide, so that the aluminum oxide can be better dispersed in the insulating coating. At the same time, it also has a good adhesion ability to the substrate, which helps to improve the glass strength and insulating performance of the insulating isolation layer. In addition, the added polyimide contains an imide structure, which has a large rigidity and can improve the modulus of the insulating isolation layer, thereby ensuring the mechanical strength of the insulating isolation layer without affecting the dispersibility of the insulating isolation layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and should not be regarded as limiting the scope. For those of ordinary skill in the art, other relevant drawings can be obtained based on these drawings without creative work. In the drawings:

[0042] Figure 1 This is a SEM image of the insulating isolation layer prepared by the method of Example 1 of the present invention;

[0043] Figure 2 This is a cross-sectional SEM image of the insulating isolation layer prepared by the method of Example 1 of the present invention;

[0044] Figure 3 This is a SEM image of the insulating isolation layer prepared by the method of Comparative Example 1 of the present invention;

[0045] Figure 4 This is a cross-sectional SEM image of the insulating isolation layer prepared by the method of Comparative Example 1 of the present invention. DETAILED DESCRIPTION

[0046] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments.

[0047] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0048] Example 1

[0049] This embodiment provides a method for preparing an insulating isolation layer of a temperature sensor, and the specific steps are as follows:

[0050] S1: Insulating isolation layer slurry, with alumina sol, deionized water and glycerol as raw materials, is mixed uniformly by ball milling, planetary dispersion and high-energy vibration in sequence, wherein the volume ratio of alumina sol, deionized water and glycerol is 17:2:1.

[0051] S2: Depositing a platinum resistor layer on the alumina substrate.

[0052] S3: Etching the platinum resistor layer into a desired pattern.

[0053] S4: Annealing the etched pattern in air to make the pattern layer dense.

[0054] S5: Perform laser resistance adjustment.

[0055] S6: coating a first layer of the insulating isolation layer slurry prepared in step S1 on the substrate by dipping and pulling, wherein the pulling speed is 50 μm / s.

[0056] S7: Dry the substrate immersed in the first insulating isolation layer in step S6 at room temperature for more than 30 minutes, and then put it in a drying oven at 200° C. for drying for 1 hour before taking it out.

[0057] S8: Immersing a second layer of the insulating isolation layer slurry prepared in step S1 on the substrate after step S7, wherein the pulling speed is 50 μm / s.

[0058] S9: Dry the substrate impregnated with the second insulating isolation layer in step S8 at room temperature for more than 30 minutes, transfer it to a muffle furnace and keep it at 200°C for 1 hour, then continue to heat it to 1000°C and keep it for 2 hours, and then cool it down naturally, with the heating rate being 5°C / min.

[0059] Three insulating isolation layers of different thicknesses were prepared by the method of Example 1, namely, group A: 1.5 μm, group B: 1.2 μm, and group C: 1 μm. The volume resistivity of the insulating isolation layers of the three thicknesses was tested, and the test results are shown in Table 1 below.

[0060] Table 1

[0061]

[0062] The microstructure of the insulating isolation layer prepared by the method of Example 1 was detected using a scanning electron microscope. Figure 1 shown.

[0063] From the above Table 1 and Figure 1 It can be seen from the test results in that the insulating isolation layer prepared by the method of this embodiment will not produce radial growth orientation, and will not have pores and cracks, has good stability, and has good insulation performance.

[0064] from Figure 1 It can be seen from the surface SEM detection results that the insulating isolation layer prepared by the method of this embodiment has a uniform surface coverage without any cracks. Figure 2 This is a cross-sectional SEM scan image. The brighter part on the lower side of the image is the platinum resistance layer, and the upper side is the aluminum oxide insulation layer. Figure 2 It can be seen that the average thickness of the insulating layer after two layers of impregnation and sintering is 1.5, there will be no radial growth orientation, no pores and cracks, good stability, and good insulation performance. The volume resistivity test results show that the volume resistivity of the insulating layer is 1.65x10 10 Ω.m, meeting insulation requirements.

[0065] Example 2

[0066] Based on Example 1, this example provides a method for preparing an insulating isolation layer of a temperature sensor. The difference from Example 1 is that the volume ratio of alumina sol, deionized water, and glycerol in this example is 13:5:3. Other technical features are exactly the same as those of Example 1. The specific steps are:

[0067] S1: Insulating isolation layer slurry, with alumina sol, deionized water and glycerol as raw materials, is mixed uniformly by ball milling, planetary dispersion and high-energy vibration in sequence, wherein the volume ratio of alumina sol, deionized water and glycerol is 13:5:3.

[0068] S2: Depositing a platinum resistor layer on the alumina substrate.

[0069] S3: Etching the platinum resistor layer into a desired pattern.

[0070] S4: annealing the etched pattern in air to make the pattern layer dense.

[0071] S5: Perform laser resistance adjustment.

[0072] S6: coating a first layer of the insulating isolation layer slurry prepared in step S1 on the substrate by dipping and pulling, wherein the pulling speed is 50 μm / s.

[0073] S7: Dry the substrate immersed in the first insulating isolation layer in step S6 at room temperature for more than 30 minutes, and then put it in a drying oven at 200° C. for drying for 1 hour before taking it out.

[0074] S8: Immersing a second layer of the insulating isolation layer slurry prepared in step S1 on the substrate after step S7, wherein the pulling speed is 50 μm / s.

[0075] S9: Dry the substrate impregnated with the second insulating isolation layer in step S8 at room temperature for more than 30 minutes, transfer it to a muffle furnace and keep it at 200°C for 1 hour, then continue to heat it to 1000°C and keep it for 2 hours, and then cool it down naturally, with the heating rate being 5°C / min.

[0076] Three insulating isolation layers of different thicknesses were prepared by the method of Example 2, namely, group A: 1.5 μm, group B: 1.2 μm, and group C: 1 μm. The volume resistivity of the insulating isolation layers of the three thicknesses was tested, and the test results are shown in Table 2 below.

[0077] Table 2

[0078]

[0079] It can be seen from the test results in Table 2 above that the insulating isolation layer prepared by the method of this embodiment has good insulating properties.

[0080] Example 3

[0081] Based on Example 1, this example provides a method for preparing an insulating isolation layer of a temperature sensor. The difference from Example 1 is that the volume ratio of alumina sol, deionized water, and glycerol in this example is 17:10:5. Other technical features are exactly the same as those of Example 1. The specific steps are:

[0082] S1: Insulating isolation layer slurry, with alumina sol, deionized water and glycerol as raw materials, is mixed uniformly by ball milling, planetary dispersion and high-energy vibration in sequence, wherein the volume ratio of alumina sol, deionized water and glycerol is 17:10:5.

[0083] S2: Depositing a platinum resistor layer on the alumina substrate.

[0084] S3: Etching the platinum resistor layer into a desired pattern.

[0085] S4: annealing the etched pattern in air to make the pattern layer dense.

[0086] S5: Perform laser resistance adjustment.

[0087] S6: coating a first layer of the insulating isolation layer slurry prepared in step S1 on the substrate by dipping and pulling, wherein the pulling speed is 50 μm / s.

[0088] S7: Dry the substrate immersed in the first insulating isolation layer in step S6 at room temperature for more than 30 minutes, and then put it in a drying oven at 200° C. for drying for 1 hour before taking it out.

[0089] S8: Immersing a second layer of the insulating isolation layer slurry prepared in step S1 on the substrate after step S7, wherein the pulling speed is 50 μm / s.

[0090] S9: Dry the substrate impregnated with the second insulating isolation layer in step S8 at room temperature for more than 30 minutes, transfer it to a muffle furnace and keep it at 200°C for 1 hour, then continue to heat it to 1000°C and keep it for 2 hours, and then cool it down naturally, with the heating rate being 5°C / min.

[0091] Three insulating isolation layers of different thicknesses were prepared by the method of Example 3, namely, Group A: 1.5 μm, Group B: 1.2 μm, and Group C: 1 μm. The volume resistivity of the insulating isolation layers of the three thicknesses was tested, and the test results are shown in Table 3 below.

[0092] Table 3

[0093]

[0094] It can be seen from the test results in Table 3 above that the insulating isolation layer prepared by the method of this embodiment has good insulating properties.

[0095] Example 4

[0096] Based on Example 1, this example provides a method for preparing an insulating isolation layer of a temperature sensor. The difference from Example 1 is that the pulling speed used in the dipping and pulling in this example is 1000 μm / s. The other technical features are exactly the same as those of Example 1. The specific steps are:

[0097] S1: Insulating isolation layer slurry, with alumina sol, deionized water and glycerol as raw materials, is mixed uniformly by ball milling, planetary dispersion and high-energy vibration in sequence, wherein the volume ratio of alumina sol, deionized water and glycerol is 10:2:1.

[0098] S2: Depositing a platinum resistor layer on the alumina substrate.

[0099] S3: Etching the platinum resistor layer into a desired pattern.

[0100] S4: annealing the etched pattern in air to make the pattern layer dense.

[0101] S5: Perform laser resistance adjustment.

[0102] S6: coating a first layer of the insulating isolation layer slurry prepared in step S1 on the substrate by dipping and pulling, wherein the pulling speed is 1000 μm / s.

[0103] S7: Dry the substrate immersed in the first insulating isolation layer in step S6 at room temperature for more than 30 minutes, and then put it in a drying oven at 200° C. for drying for 1 hour before taking it out.

[0104] S8: Immersing a second layer of the insulating isolation layer slurry prepared in step S1 on the substrate after step S7, wherein the pulling speed is 1000 μm / s.

[0105] S9: Dry the substrate impregnated with the second insulating isolation layer in step S8 at room temperature for more than 30 minutes, transfer it to a muffle furnace and keep it at 200°C for 1 hour, then continue to heat it to 1000°C and keep it for 2 hours, and then cool it down naturally, with the heating rate being 5°C / min.

[0106] Three insulating isolation layers of different thicknesses were prepared by the method of Example 4, namely, group A: 1.5 μm, group B: 1.2 μm, and group C: 1 μm. The volume resistivity of the insulating isolation layers of the three thicknesses was tested, and the test results are shown in Table 4 below.

[0107] Table 4

[0108]

[0109] It can be seen from the test results in Table 4 above that the insulating isolation layer prepared by the method of this embodiment has good insulating properties.

[0110] Example 5

[0111] Based on Example 1, this example provides a method for preparing an insulating isolation layer of a temperature sensor. The difference from Example 1 is that the pulling speed used in this example during immersion pulling is 5000 μm / s. The other technical features are exactly the same as those of Example 1. The specific steps are:

[0112] S1: Insulating isolation layer slurry, with alumina sol, deionized water and glycerol as raw materials, is mixed uniformly by ball milling, planetary dispersion and high-energy vibration in sequence, wherein the volume ratio of alumina sol, deionized water and glycerol is 10:2:1.

[0113] S2: Depositing a platinum resistor layer on the alumina substrate.

[0114] S3: Etching the platinum resistor layer into a desired pattern.

[0115] S4: Annealing the etched pattern in air to make the pattern layer dense.

[0116] S5: Perform laser resistance adjustment.

[0117] S6: coating a first layer of the insulating isolation layer slurry prepared in step S1 on the substrate by dipping and pulling, wherein the pulling speed is 5000 μm / s.

[0118] S7: Dry the substrate immersed in the first insulating isolation layer in step S6 at room temperature for more than 30 minutes, and then put it in a drying oven at 200° C. for drying for 1 hour before taking it out.

[0119] S8: Immersing a second layer of the insulating isolation layer slurry prepared in step S1 on the substrate after step S7, wherein the pulling speed is 5000 μm / s.

[0120] S9: Dry the substrate impregnated with the second insulating isolation layer in step S8 at room temperature for more than 30 minutes, transfer it to a muffle furnace and keep it at 200°C for 1 hour, then continue to heat it to 1000°C and keep it for 2 hours, and then cool it down naturally, with the heating rate being 5°C / min.

[0121] Three insulating isolation layers of different thicknesses were prepared by the method of Example 5, namely, Group A: 1.5 μm, Group B: 1.2 μm, and Group C: 1 μm. The volume resistivity of the insulating isolation layers of the three thicknesses was tested, and the test results are shown in Table 5 below.

[0122] Table 5

[0123]

[0124] It can be seen from the test results in Table 5 above that the insulating isolation layer prepared by the method of this embodiment has good insulating properties.

[0125] Example 6

[0126] Based on Example 1, this example provides a method for preparing an insulating isolation layer of a temperature sensor. The difference from Example 1 is that the sintering temperature in this example is 1200°C and the sintering time is 2 hours. The other technical features are exactly the same as those of Example 1. The specific steps are:

[0127] S1: Insulating isolation layer slurry, with alumina sol, deionized water and glycerol as raw materials, is mixed uniformly by ball milling, planetary dispersion and high-energy vibration in sequence, wherein the volume ratio of alumina sol, deionized water and glycerol is 10:2:1.

[0128] S2: Depositing a platinum resistor layer on the alumina substrate.

[0129] S3: Etching the platinum resistor layer into a desired pattern.

[0130] S4: annealing the etched pattern in air to make the pattern layer dense.

[0131] S5: Perform laser resistance adjustment.

[0132] S6: coating a first layer of the insulating isolation layer slurry prepared in step S1 on the substrate by dipping and pulling, wherein the pulling speed is 50 μm / s.

[0133] S7: Dry the substrate immersed in the first insulating isolation layer in step S6 at room temperature for more than 30 minutes, and then put it in a drying oven at 200° C. for drying for 1 hour before taking it out.

[0134] S8: Immersing a second layer of the insulating isolation layer slurry prepared in step S1 on the substrate after step S7, wherein the pulling speed is 50 μm / s.

[0135] S9: Dry the substrate impregnated with the second insulating isolation layer in step S8 at room temperature for more than 30 minutes, transfer it to a muffle furnace and keep it at 200°C for 1 hour, then continue to heat it to 1200°C and keep it for 2 hours, and then cool it down naturally, with the heating rate being 5°C / min.

[0136] Three insulating isolation layers of different thicknesses were prepared by the method of Example 6, namely, Group A: 1.5 μm, Group B: 1.2 μm, and Group C: 1 μm. The volume resistivity of the insulating isolation layers of the three thicknesses was tested, and the test results are shown in Table 6 below.

[0137] Table 6

[0138]

[0139] It can be seen from the test results in Table 6 above that the insulating isolation layer prepared by the method of this embodiment has good insulating properties.

[0140] Example 7

[0141] Based on Example 1, this example provides a method for preparing an insulating isolation layer of a temperature sensor. The difference from Example 1 is that the sintering temperature in this example is 1500°C and the sintering time is 30 minutes. The other technical features are exactly the same as those of Example 1. The specific steps are:

[0142] S1: Insulating isolation layer slurry, with alumina sol, deionized water and glycerol as raw materials, is mixed uniformly by ball milling, planetary dispersion and high-energy vibration in sequence, wherein the volume ratio of alumina sol, deionized water and glycerol is 10:2:1.

[0143] S2: Depositing a platinum resistor layer on the alumina substrate.

[0144] S3: Etching the platinum resistor layer into a desired pattern.

[0145] S4: Annealing the etched pattern in air to make the pattern layer dense.

[0146] S5: Perform laser resistance adjustment.

[0147] S6: coating a first layer of the insulating isolation layer slurry prepared in step S1 on the substrate by dipping and pulling, wherein the pulling speed is 50 μm / s.

[0148] S7: Dry the substrate immersed in the first insulating isolation layer in step S6 at room temperature for more than 30 minutes, and then put it in a drying oven at 200° C. for drying for 1 hour before taking it out.

[0149] S8: Immersing a second layer of the insulating isolation layer slurry prepared in step S1 on the substrate after step S7, wherein the pulling speed is 50 μm / s.

[0150] S9: Dry the substrate impregnated with the second insulating isolation layer in step S8 at room temperature for more than 30 minutes, transfer it to a muffle furnace and keep it at 200°C for 1 hour, then continue to heat it to 1500°C and keep it for 2 hours, and then cool it down naturally, with the heating rate being 5°C / min.

[0151] Three insulating isolation layers of different thicknesses were prepared by the method of Example 7, namely, Group A: 1.5 μm, Group B: 1.2 μm, and Group C: 1 μm. The volume resistivity of the insulating isolation layers of the three thicknesses was tested, and the test results are shown in Table 7 below.

[0152] Table 7

[0153]

[0154] It can be seen from the test results in Table 7 above that the insulating isolation layer prepared by the method of this embodiment has good insulating properties.

[0155] Example 8

[0156] Based on Example 1, this example provides a method for preparing an insulating isolation layer of a temperature sensor. The difference from Example 1 is that the formula of the insulating layer isolation liquid in this example is different from that in Example 1. The other technical features are exactly the same as those in Example 1. The specific steps are:

[0157] S1: Insulation isolation layer slurry, using titanium dioxide modified alumina sol, deionized water, and glycerol as raw materials, and mixed evenly by ball milling, planetary dispersion, and high-energy vibration in sequence, wherein the volume ratio of titanium dioxide modified alumina sol, deionized water, and glycerol is 10:2:1;

[0158] The mass of titanium dioxide added to the titanium dioxide-modified alumina sol is 2% of the mass of the alumina sol, and the added adhesive is polyvinylidene fluoride, and the added amount is 10% of the mass of the alumina sol.

[0159] S2: Depositing a platinum resistor layer on the alumina substrate.

[0160] S3: Etching the platinum resistor layer into a desired pattern.

[0161] S4: Annealing the etched pattern in air to make the pattern layer dense.

[0162] S5: Perform laser resistance adjustment.

[0163] S6: coating a first layer of the insulating isolation layer slurry prepared in step S1 on the substrate by dipping and pulling, wherein the pulling speed is 50 μm / s.

[0164] S7: Dry the substrate immersed in the first insulating isolation layer in step S6 at room temperature for more than 30 minutes, and then put it in a drying oven at 200° C. for drying for 1 hour before taking it out.

[0165] S8: Immersing a second layer of the insulating isolation layer slurry prepared in step S1 on the substrate after step S7, wherein the pulling speed is 50 μm / s.

[0166] S9: Dry the substrate impregnated with the second insulating isolation layer in step S8 at room temperature for more than 30 minutes, transfer it to a muffle furnace and keep it at 200°C for 1 hour, then continue to heat it to 1000°C and keep it for 2 hours, and then cool it down naturally, with the heating rate being 5°C / min.

[0167] Three insulating isolation layers of different thicknesses were prepared by the method of Example 8, namely, Group A: 1.5 μm, Group B: 1.2 μm, and Group C: 1 μm. The volume resistivity of the insulating isolation layers of the three thicknesses was tested, and the test results are shown in Table 8 below.

[0168] Table 8

[0169]

[0170] It can be seen from the test results in the above Table 8 that the insulating isolation layer prepared by the method of this embodiment has good insulating properties and is significantly better than the insulating isolation layers prepared by the methods of Examples 1 to 7, indicating that the addition of titanium dioxide and a binder promotes the insulating isolation properties of the prepared insulating isolation layer.

[0171] Example 9

[0172] Based on Example 1, this example provides a method for preparing an insulating isolation layer of a temperature sensor. The difference from Example 1 is that the formula of the insulating layer isolation liquid in this example is different from that in Example 1. The other technical features are exactly the same as those in Example 1. The specific steps are:

[0173] S1: Insulation isolation layer slurry, using titanium dioxide modified alumina sol, deionized water, and glycerol as raw materials, and mixed evenly by ball milling, planetary dispersion, and high-energy vibration in sequence, wherein the volume ratio of titanium dioxide modified alumina sol, deionized water, and glycerol is 10:2:1;

[0174] The mass of titanium dioxide added to the titanium dioxide-modified alumina sol is 3% of the mass of the alumina sol, and the added adhesive is polyvinylidene fluoride, and the added amount is 12% of the mass of the alumina sol.

[0175] S2: Depositing a platinum resistor layer on the alumina substrate.

[0176] S3: Etching the platinum resistor layer into a desired pattern.

[0177] S4: annealing the etched pattern in air to make the pattern layer dense.

[0178] S5: Perform laser resistance adjustment.

[0179] S6: coating a first layer of the insulating isolation layer slurry prepared in step S1 on the substrate by dipping and pulling, wherein the pulling speed is 50 μm / s.

[0180] S7: Dry the substrate immersed in the first insulating isolation layer in step S6 at room temperature for more than 30 minutes, and then put it in a drying oven at 200° C. for drying for 1 hour before taking it out.

[0181] S8: Immersing a second layer of the insulating isolation layer slurry prepared in step S1 on the substrate after step S7, wherein the pulling speed is 50 μm / s.

[0182] S9: Dry the substrate impregnated with the second insulating isolation layer in step S8 at room temperature for more than 30 minutes, transfer it to a muffle furnace and keep it at 200°C for 1 hour, then continue to heat it to 1000°C and keep it for 2 hours, and then cool it down naturally, with the heating rate being 5°C / min.

[0183] Three different thicknesses of insulating isolation layers were prepared by the method of Example 9, namely, Group A: 1.5 μm, Group B: 1.2 μm, and Group C: 1 μm. The volume resistivity of the insulating isolation layers of the three thicknesses was tested, and the test results are shown in Table 9 below.

[0184] Table 9

[0185]

[0186] It can be seen from the test results in Table 9 that the insulating isolation layer prepared by the method of this embodiment has good insulating properties, and is significantly better than the insulating isolation layers prepared by the methods of Examples 1 to 7, indicating that the addition of titanium dioxide and a binder promotes the insulating isolation properties of the prepared insulating isolation layer.

[0187] Example 10

[0188] Based on Example 1, this example provides a method for preparing an insulating isolation layer of a temperature sensor. The difference from Example 1 is that the formula of the insulating layer isolation liquid in this example is different from that in Example 1. The other technical features are exactly the same as those in Example 1. The specific steps are:

[0189] S1: Insulation isolation layer slurry, using titanium dioxide modified alumina sol, deionized water, and glycerol as raw materials, and mixed evenly by ball milling, planetary dispersion, and high-energy vibration in sequence, wherein the volume ratio of titanium dioxide modified alumina sol, deionized water, and glycerol is 10:2:1;

[0190] The mass of titanium dioxide added to the titanium dioxide-modified alumina sol is 5% of the mass of the alumina sol, and the added adhesive is polyvinylidene fluoride, and the added amount is 15% of the mass of the alumina sol.

[0191] S2: Depositing a platinum resistor layer on the alumina substrate.

[0192] S3: Etching the platinum resistor layer into a desired pattern.

[0193] S4: annealing the etched pattern in air to make the pattern layer dense.

[0194] S5: Perform laser resistance adjustment.

[0195] S6: coating a first layer of the insulating isolation layer slurry prepared in step S1 on the substrate by dipping and pulling, wherein the pulling speed is 50 μm / s.

[0196] S7: Dry the substrate immersed in the first insulating isolation layer in step S6 at room temperature for more than 30 minutes, and then put it in a drying oven at 200° C. for drying for 1 hour before taking it out.

[0197] S8: Immersing a second layer of the insulating isolation layer slurry prepared in step S1 on the substrate after step S7, wherein the pulling speed is 50 μm / s.

[0198] S9: Dry the substrate impregnated with the second insulating isolation layer in step S8 at room temperature for more than 30 minutes, transfer it to a muffle furnace and keep it at 200°C for 1 hour, then continue to heat it to 1000°C and keep it for 2 hours, and then cool it down naturally, with the heating rate being 5°C / min.

[0199] Three insulating isolation layers of different thicknesses were prepared by the method of Example 10, namely, Group A: 1.5 μm, Group B: 1.2 μm, and Group C: 1 μm. The volume resistivity of the insulating isolation layers of the three thicknesses was tested, and the test results are shown in Table 10 below.

[0200] Table 10

[0201]

[0202] It can be seen from the test results in Table 10 that the insulating isolation layer prepared by the method of this embodiment has good insulating properties, and is significantly better than the insulating isolation layers prepared by the methods of Examples 1 to 7, indicating that the addition of titanium dioxide and a binder promotes the insulating isolation properties of the prepared insulating isolation layer.

[0203] Embodiment 11

[0204] Based on Example 8, this example provides a method for preparing an insulating isolation layer of a temperature sensor. The difference from Example 8 is that the binder added in this example is polyimide. The other technical features are exactly the same as those of Example 8. The specific steps are:

[0205] S1: Insulation isolation layer slurry, using titanium dioxide modified alumina sol, deionized water, and glycerol as raw materials, and mixed evenly by ball milling, planetary dispersion, and high-energy vibration in sequence, wherein the volume ratio of titanium dioxide modified alumina sol, deionized water, and glycerol is 10:2:1;

[0206] The mass of titanium dioxide added to the titanium dioxide-modified alumina sol is 2% of the mass of the alumina sol; the added adhesive is polyimide, and the added amount is 10% of the mass of the alumina sol.

[0207] S2: Depositing a platinum resistor layer on the alumina substrate.

[0208] S3: Etching the platinum resistor layer into a desired pattern.

[0209] S4: annealing the etched pattern in air to make the pattern layer dense.

[0210] S5: Perform laser resistance adjustment.

[0211] S6: coating a first layer of the insulating isolation layer slurry prepared in step S1 on the substrate by dipping and pulling, wherein the pulling speed is 50 μm / s.

[0212] S7: Dry the substrate immersed in the first insulating isolation layer in step S6 at room temperature for more than 30 minutes, and then put it in a drying oven at 200° C. for drying for 1 hour before taking it out.

[0213] S8: Immersing a second layer of the insulating isolation layer slurry prepared in step S1 on the substrate after step S7, wherein the pulling speed is 50 μm / s.

[0214] S9: Dry the substrate impregnated with the second insulating isolation layer in step S8 at room temperature for more than 30 minutes, transfer it to a muffle furnace and keep it at 200°C for 1 hour, then continue to heat it to 1000°C and keep it for 2 hours, and then cool it down naturally, with the heating rate being 5°C / min.

[0215] Three insulating isolation layers with different thicknesses were prepared by the method of Example 11, namely, Group A: 1.5 μm, Group B: 1.2 μm, and Group C: 1 μm. The volume resistivity of the insulating isolation layers with the three thicknesses was tested, and the test results are shown in Table 11 below.

[0216] Table 11

[0217]

[0218] It can be seen from the test results in the above Table 11 that the insulating isolation layer prepared by the method of this embodiment has good insulating properties and is significantly better than the insulating isolation layers prepared by the methods of Examples 1 to 7, indicating that the addition of titanium dioxide and a binder promotes the insulating isolation properties of the prepared insulating isolation layer.

[0219] Example 12

[0220] Based on Example 8, this example provides a method for preparing an insulating isolation layer of a temperature sensor. The difference from Example 8 is that the binder added in this example is a mixture of polyimide and polyvinylidene fluoride, and the ratio of the two is 1:1. The other technical features are exactly the same as those of Example 8. The specific steps are:

[0221] S1: Insulation isolation layer slurry, using titanium dioxide modified alumina sol, deionized water, and glycerol as raw materials, and mixed evenly by ball milling, planetary dispersion, and high-energy vibration in sequence, wherein the volume ratio of titanium dioxide modified alumina sol, deionized water, and glycerol is 10:2:1;

[0222] The mass of titanium dioxide added to the titanium dioxide-modified alumina sol is 2% of the mass of the alumina sol; the added adhesive is a mixture of polyimide and polyvinylidene fluoride, and the added amount is 10% of the mass of the alumina sol.

[0223] S2: Depositing a platinum resistor layer on the alumina substrate.

[0224] S3: Etching the platinum resistor layer into a desired pattern.

[0225] S4: Annealing the etched pattern in air to make the pattern layer dense.

[0226] S5: Perform laser resistance adjustment.

[0227] S6: coating a first layer of the insulating isolation layer slurry prepared in step S1 on the substrate by dipping and pulling, wherein the pulling speed is 50 μm / s.

[0228] S7: Dry the substrate immersed in the first insulating isolation layer in step S6 at room temperature for more than 30 minutes, and then put it in a drying oven at 200° C. for drying for 1 hour before taking it out.

[0229] S8: Immersing a second layer of the insulating isolation layer slurry prepared in step S1 on the substrate after step S7, wherein the pulling speed is 50 μm / s.

[0230] S9: Dry the substrate impregnated with the second insulating isolation layer in step S8 at room temperature for more than 30 minutes, transfer it to a muffle furnace and keep it at 200°C for 1 hour, then continue to heat it to 1000°C and keep it for 2 hours, and then cool it down naturally, with the heating rate being 5°C / min.

[0231] Three insulating isolation layers of different thicknesses were prepared by the method of Example 12, namely, Group A: 1.5 μm, Group B: 1.2 μm, and Group C: 1 μm. The volume resistivity of the insulating isolation layers of the three thicknesses was tested, and the test results are shown in Table 12 below.

[0232] Table 12

[0233]

[0234] It can be seen from the test results in the above Table 12 that the insulating isolation layer prepared by the method of this embodiment has good insulating properties, and is significantly better than the insulating isolation layers prepared by the methods of Examples 1 to 7, indicating that the addition of titanium dioxide and a binder promotes the insulating isolation properties of the prepared insulating isolation layer. At the same time, the insulating isolation properties are better than those of Examples 8 to 11, indicating that the addition of polyvinylidene fluoride and polyimide as a binder at the same time has a better effect on improving the insulating isolation properties of the insulating isolation layer.

[0235] Comparative Example 1

[0236] This comparative example provides a method for preparing an insulating isolation layer of a temperature sensor, and the specific steps are:

[0237] S1: Insulating isolation layer slurry, with alumina sol, deionized water and glycerol as raw materials, is mixed uniformly by ball milling, planetary dispersion and high-energy vibration in sequence, wherein the volume ratio of alumina sol, deionized water and glycerol is 17:2:1.

[0238] S2: Depositing a platinum resistor layer on the alumina substrate.

[0239] S3: Etching the platinum resistor layer into a desired pattern.

[0240] S4: Annealing the etched pattern in air to make the pattern layer dense.

[0241] S5: Perform laser resistance adjustment.

[0242] S6: coating a first layer of the insulating isolation layer slurry prepared in step S1 on the substrate by dipping and pulling, wherein the pulling speed is 50 μm / s.

[0243] S7: Dry the substrate immersed in the first insulating isolation layer in step S6 at room temperature for more than 30 minutes, and then put it in a drying oven at 100° C. for 1 hour before taking it out.

[0244] S8: Immersing a second layer of the insulating isolation layer slurry prepared in step S1 on the substrate after step S7, wherein the pulling speed is 50 μm / s.

[0245] S9: Dry the substrate impregnated with the second insulating isolation layer in step S8 at room temperature for more than 30 minutes, transfer it to a muffle furnace and keep it at 200°C for 1 hour, then continue to heat it to 1000°C and keep it for 2 hours, and then cool it down naturally, with the heating rate being 5°C / min.

[0246] The main difference between this comparative example and the embodiment lies in the drying temperature after the first insulating layer is impregnated. Under the same drying time, the drying temperature of the comparative example is low, and the first layer is not completely dried, so that cracks are generated after the subsequent processes, resulting in poor dense insulation.

[0247] from Figure 3 It can be seen from the figure that the insulating isolation layer prepared by the method of this comparative example has a large number of cracks in the surface grooves. Figure 4 As can be seen from the figure, the brighter part on the lower side is the platinum resistance layer, and the upper side is the aluminum oxide insulation layer. Figure 4It can be seen that the average thickness of the two insulating layers after impregnation and sintering is 1.5, and no radial growth orientation will be produced. There are no pores and cracks in the insulating layer covering the platinum thin film resistor layer. Cracks appear at the connection between the groove and the platinum thin film resistor layer. The insulating layer cannot form a good seal for the resistor layer, resulting in a decrease in insulation.

[0248] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing an insulating isolation layer of a temperature sensor, characterized in that: The following steps are involved: depositing a platinum resistance layer on an alumina substrate; Etching the platinum resistance layer into a desired pattern; Annealing the etched pattern in air to make the pattern layer dense; Perform laser resistance trimming; Prepare an insulating isolation layer slurry, and apply the insulating isolation layer slurry on the substrate by dipping and pulling; After the insulating layer slurry is applied, it is sintered in the air; The formula for preparing the insulating isolation layer slurry includes alumina sol, deionized water, and glycerol; the volume ratio of the alumina sol, deionized water, and glycerol is (10-17): (2-10): (1-5); The alumina sol is modified by titanium dioxide, the addition amount of the titanium dioxide is 2% or 5% of the mass of the alumina sol, and a binder is added during the modification process, the addition amount of the binder is 10% to 15% of the mass of the alumina sol; The binder includes any one of polyvinylidene fluoride and polyimide or a combination of the two.

2. The method for preparing an insulating isolation layer of a temperature sensor according to claim 1, characterized in that: The pulling speed during the immersion pulling coating of the insulating isolation layer slurry is 50 μm / s to 5000 μm / s.

3. The method for preparing an insulating isolation layer of a temperature sensor according to claim 1, characterized in that: The number of dipping and pulling is at least one; when multiple dipping and pulling are required, the next dipping and pulling can only be carried out after complete drying after the previous dipping and pulling.

4. The method for preparing an insulating isolation layer of a temperature sensor according to claim 3, characterized in that: The drying temperature is 75℃~300℃.

5. The method for preparing an insulating isolation layer of a temperature sensor according to claim 3, characterized in that: The drying time is 10min to 2h.

6. The method for preparing an insulating isolation layer of a temperature sensor according to claim 1, characterized in that: The sintering temperature in air is 1000°C to 1500°C.

7. The method for preparing an insulating isolation layer of a temperature sensor according to claim 1, characterized in that: The sintering time in air is 30 minutes to 5 hours.

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