Film preparation method based on sputtering technology, temperature-sensitive film and temperature sensor

Abstract

The invention relates to the technical field of film temperature sensors, in particular to a film preparation method based on the sputtering technology, a temperature-sensitive film and a temperature sensor.The temperature sensor comprises an adhesion layer, an insulation layer is arranged on the adhesion layer, a temperature-sensitive layer is arranged on the insulation layer, the adhesion layer is made of NiCrAlY materials, the insulation layer is made of high-melting-point metal oxide materials, and the temperature-sensitive layer is made of high-melting-point metal oxide materials. The temperature-sensitive layer is an ITO-Al2O3 composite film with the mass ratio of Al to In being 1-10 wt%, the adhesion layer of the temperature-sensitive film is used for being adhered to a measured component, and a platinum wire is led out of the temperature-sensitive layer of the temperature-sensitive film to transmit electric signals. Compared with a pure ITO thin film temperature sensor not doped with Al2O3, the thin film temperature sensor based on the temperature-sensitive thin film has the advantages that a repeatability error order of magnitude is remarkably reduced, and the measurement reliability of the thin film temperature sensor based on the temperature-sensitive thin film under an extreme working condition is effectively guaranteed.

Description

Technical Field

[0001] The present invention relates to the technical field of thin film temperature sensors, and in particular to a thin film preparation method based on sputtering technology, a temperature-sensitive film and a temperature sensor. Background Art

[0002] Aerospace and nuclear equipment urgently require accurate temperature measurements in extremely high-temperature environments (>1000°C). Traditional temperature measurement components, such as armored thermocouples, are difficult to implement due to their large size, invasive installation (drilling and welding), and long response times (on the order of seconds). Thin-film temperature sensors offer advantages such as low cost, high spatial and temporal resolution (microseconds), and non-invasive integration, providing an effective technical solution to these challenges.

[0003] ITO has a high melting point (≥1500°C) and high electrical conductivity (10 -4 The unique combination of ITO (ITO) and Ωcm makes it one of the most commonly used materials for high-temperature thin-film temperature sensors. However, in existing ITO thin-film temperature sensors, structural and chemical stability degradation due to oxidation, grain growth, and defect formation at high temperatures alters the carrier concentration (n) and transport properties (μ) within the film. According to the equation 1-σ = ρ = 1-nqμ (σ, ρ, n, q, μ are the film's conductivity, resistivity, carrier concentration, charge, and carrier mobility, respectively), changes in carrier concentration and mobility lead to irreversible changes in the film's conductivity-resistivity ratio. This, in turn, results in high repeatability errors exceeding 20% ​​during cyclic testing, severely reducing the reliability of test results.

[0004] To improve the high-temperature performance of ITO thin-film temperature sensors, existing techniques have proposed reducing repeatability errors by adding an additional Al-Al2O3 protective layer. However, this approach inevitably increases sensor fabrication time and cost, and the differences in thermal expansion coefficients of heterogeneous materials can easily lead to delamination failure under large temperature gradients. This highlights the need to develop thin-film temperature sensors with inherently high thermal stability and low repeatability errors.

[0005] Therefore, it is necessary to provide a thin film preparation method based on sputtering technology, a temperature-sensitive film and a temperature sensor to solve the above problems. Summary of the Invention

[0006] In order to solve the problem that the existing methods inevitably increase the preparation time and cost of devices, and the difference in thermal expansion coefficients of heterogeneous materials easily leads to delamination failure under large temperature gradients, the present invention provides a thin film preparation method, a temperature-sensitive film and a temperature sensor based on sputtering technology to solve the existing problems.

[0007] The first aspect of the present invention provides a temperature-sensitive film, which adopts the following technical solution, including: Adhesive layer, on which an insulating layer is provided, and on which a temperature-sensitive layer is provided The adhesion layer is made of NiCrAlY material, the insulation layer is made of high-melting-point metal oxide material, and the temperature-sensitive layer is an ITO-Al2O3 composite film with a mass ratio of Al to In of 1-10wt%.

[0008] Preferably, the thickness of the adhesive layer is 5-30 μm.

[0009] Preferably, the insulating layer is made of Al2O3, CeO2 or HfO2 material.

[0010] Preferably, the thickness of the insulating layer is 2-4 μm.

[0011] Preferably, the thickness of the temperature-sensitive layer is 1-10 μm.

[0012] The second aspect of the present invention provides a method for preparing a temperature-sensitive thin film based on sputtering technology, which adopts the following technical solution, including: Adhesion layer sputtered on the tested component using 99.99% pure NiCrAlY target in a magnetron sputtering machine; sputtering an insulating layer on the adhesion layer using a metal oxide target; Coating photoresist on the surface of the insulating layer, and performing UV exposure and development using a mask, and then performing photolithography on the insulating layer coated with the photoresist to obtain a patterned area of ​​the temperature-sensitive layer; An ITO-Al2O3 doped target or an ITO and Al2O3 dual target is used to sputter a 1-10 μm ITO-Al2O3 composite film in a patterned area of ​​the temperature-sensitive layer; and the photoresist is cleaned and dried to obtain the temperature-sensitive film.

[0013] Preferably, the photoresist is coated on the surface of the insulating layer by spin coating technology.

[0014] Preferably, a serpentine gate mask is used for UV exposure and development.

[0015] Preferably, based on magnetron sputtering technology, an ITO-Al2O3 doped target or an ITO and Al2O3 dual target is used for sputtering deposition in the patterned area of ​​the temperature sensitive layer to form an ITO-Al2O3 composite film.

[0016] The third aspect of the present invention provides a thin film temperature sensor, comprising: a temperature-sensitive film of the present invention, wherein the adhesive layer of the temperature-sensitive film is used to adhere to the component to be measured, and a platinum wire is led out of the temperature-sensitive layer of the temperature-sensitive film to transmit an electrical signal. The beneficial effects of the present invention are: This invention significantly improves the thermal stability of ITO thin films at high temperatures by introducing Al2O3 as a second phase into the thin film. On the one hand, Al-O bonds have higher bonding strength and high-temperature stability than In-O bonds. On the other hand, due to the Zener pinning effect, the dispersed Al2O3 phase effectively hinders the growth and interfacial migration of ITO grains at high temperatures, thereby improving the structural stability of the film. Repeatability test results show that the temperature sensor based on the ITO-Al2O3 thin film exhibits a repeatability error as low as 3.3% in a cyclic test from 25-1200°C. Compared with the pure ITO thin film temperature sensor without Al2O3 doping (repeatability error as high as 25.6%), this is a significant reduction of one order of magnitude, effectively ensuring the measurement reliability of the thin film temperature sensor under extreme operating conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0018] Figure 1 Schematic diagram of the structure of a temperature-sensitive film of the present invention; Figure 2 This is a schematic structural diagram of a thin film temperature sensor prepared on the surface of an aircraft engine turbine blade in the embodiment of the present invention; Figure 3 This is a flow chart of a thin film temperature sensor prepared on the surface of an aircraft engine turbine blade in the implementation of the present invention; Figure 4 This is an SEM image of a thin film temperature sensor prepared in the embodiment of the present invention; Figure 5 This is the EDS spectrum of the thin film temperature sensor prepared in the embodiment of the present invention; Figure 6 This is a resistance-temperature curve of an undoped Al2O3 ITO thin film temperature sensor in a 25-1200°C cycle test in an embodiment of the present invention; Figure 7 The figure shows the resistance-temperature curve of the Al2O3-doped ITO thin film temperature sensor in a 25-1200°C cycle test according to the present invention. DETAILED DESCRIPTION

[0019] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0020] An embodiment of a temperature-sensitive film of the present invention is as follows Figure 1 As shown, the device comprises: an adhesion layer 2, an insulating layer 3, and a temperature-sensitive layer 4, wherein the insulating layer 3 is disposed on the adhesion layer 2, and the temperature-sensitive layer 4 is disposed on the insulating layer 3. The adhesion layer 2 is made of NiCrAlY material, the insulating layer 3 is made of a high-melting-point metal oxide material, and the temperature-sensitive layer 4 is an ITO-Al2O3 composite film having a mass ratio of Al to In of 1-10 wt%. In this embodiment, the mass ratio of Al to In is 2.43 wt%. It should be noted that pure ITO films are susceptible to grain coarsening and defect formation at high temperatures, resulting in increased resistivity. Al2O3 nanoparticles act as a pinning phase, hindering the migration of ITO grain boundaries through the Zener pinning effect, inhibiting excessive grain growth and maintaining the nanocrystalline structure of the film. Therefore, in this embodiment, 2.43 wt% Al2O3 is introduced into ITO as a second phase, which can inhibit the degradation of the high-temperature performance of the ITO film and improve the high-temperature performance of the device.

[0021] For example, in a specific embodiment, the thickness of the adhesion layer 2 is 5-30 μm.

[0022] For example, in a specific embodiment, the insulating layer 3 is made of Al2O3, CeO2 or HfO2 material.

[0023] For example, in a specific embodiment, the thickness of the insulating layer 3 is 2-4 μm.

[0024] For example, in a specific embodiment, the thickness of the temperature-sensitive layer 4 is 1-10 μm.

[0025] An embodiment of a method for preparing a temperature-sensitive thin film based on sputtering technology of the present invention comprises: Step 1: Using a 99.99% high-purity NiCrAlY target material in a magnetron sputtering machine, an adhesion layer 2 with a thickness of 20 μm is sputtered on the component to be tested 1; Step 2: sputtering an insulating layer 3 with a thickness of 3 μm on the adhesion layer 2 using a metal oxide target; Step 3: coating the surface of the insulating layer 3 with photoresist, and performing UV exposure and development using a mask, and then performing photolithography on the insulating layer 3 coated with the photoresist to obtain a patterned area of ​​the temperature-sensitive layer 4; Step 4: Use ITO-Al2O3 doped target or ITO and Al2O3 dual target to sputter in the patterned area of ​​the temperature-sensitive layer 4 to prepare a 5 μm ITO-Al2O3 composite film; and clean the photoresist and dry it to obtain the temperature-sensitive film.

[0026] For example, in a specific embodiment, a serpentine gate mask is used for UV exposure and development.

[0027] For example, in a specific embodiment, based on magnetron sputtering technology, an ITO-Al2O3 doped target or an ITO and Al2O3 dual target is used for sputtering deposition to form an ITO-Al2O3 composite film in the patterned area of ​​the temperature-sensitive layer 4.

[0028] An embodiment of a thin film temperature sensor of the present invention comprises: the temperature-sensitive film of the present invention, wherein the adhesive layer 2 of the temperature-sensitive film is used to adhere to the measured component 1, and the temperature-sensitive layer 4 of the temperature-sensitive film leads to a platinum wire to transmit an electrical signal.

[0029] The following describes the thin film temperature sensor of the present invention in combination with specific application scenarios and experimental data: like Figure 2 As shown in FIG, a schematic diagram of preparing a thin film temperature sensor on the surface of an aircraft engine turbine blade is shown in FIG. Figure 2 As shown, from bottom to top are K465 nickel-based high-temperature alloy, an adhesion layer 2 of NiCrAlY material, an insulation layer 3 of Al2O3-HfO2 material, and a temperature-sensitive layer 4 of ITO-Al2O3 material.

[0030] like Figure 3 As shown, the preparation steps of the thin film temperature sensor are: Step 1: Use anhydrous ethanol, acetone, and deionized water to ultrasonically and electrolytically degrease and clean the surface of the aircraft engine turbine blade.

[0031] Step 2: Place the aircraft engine turbine blade in a magnetron sputtering machine and use a 99.99% NiCrAlY target (Ni:Cr:Al:Y=67:22:10:1wt%) to sputter a 12μm adhesion layer 2. The vacuum in the magnetron sputtering machine is set to 9×10 -4 Pa, the working pressure is set to 1.2 Pa, and the power density is 5 W-cm 2 .

[0032] Step 3: 99.99% Al2O3 and 99.99% HfO2 targets were used to sputter the surface of the NiCrAlY adhesion layer 2 in step 2 to form an Al2O3-HfO2 insulating layer 3. The background vacuum was set to 9×10 -4 Pa, the working pressure is set to 1.0 Pa, and the power density is 4 W-cm 2 , thickness 2-3μm.

[0033] Step 4: Spin-coat photoresist on the surface of the insulating layer 3, perform UV exposure using a serpentine gate mask, and develop.

[0034] Step 5: Place the aero-engine turbine blades that have completed step 4 into the sputtering machine and use ITO-Al2O3 doped target to sputter a temperature-sensitive layer with a thickness of 3 μm. The background vacuum is set to 5×10 -4 Pa, the working pressure is set to 0.4Pa, the power density is 3W-cm 2 .

[0035] Step 6: Use acetone to wash away the photoresist, rinse with deionized water, and dry.

[0036] Step 7: Use platinum paste and platinum wire to complete the electrical signal lead-out. The curing process is room temperature for 24 hours, and then at 700°C for 10 minutes.

[0037] like Figure 4 As shown in FIG. 1 , the microscopic morphology of the ITO-Al2O3 temperature-sensitive layer 4 deposited on the surface of the Al2O3-HfO2 insulating layer 3 by magnetron sputtering. That is, the temperature-sensitive film is dense and defect-free, and the grains are closely arranged. Figure 5 As shown, the Al-In ratio in its chemical composition is 2.43wt%.

[0038] In order to verify the repeatability of the thin film temperature sensor of the present invention in the cycle test, a repeatability test was conducted on the thin film temperature sensor in the embodiment, and an undoped ITO thin film temperature sensor prepared with the same process parameters was used as a control. Figure 6 The resistance-temperature curve of the undoped ITO thin film temperature sensor in the 25-1200°C cycle test is shown in Figure 2. Figure 6 The curve in Figure 2 shows severe inconsistency during multiple thermal cycles, with a repeatability error of 25.6%. Figure 7 The resistance-temperature curve of the thin film temperature sensor prepared in this embodiment during the 25-1200°C cycle test is shown in FIG. Figure 7 The curves showed significantly improved consistency during the cyclic test, with the repeatability error significantly reduced to 3.3%. The effect of Al2O3 doping concentration on the repeatability of the ITO thin film temperature sensor is shown in Table 1. The results in Table 1 indicate that low-concentration Al2O3 doping has a more significant effect on improving the repeatability of the ITO thin film temperature sensor than high-concentration doping.

[0039] Table 1

[0040] The above description is only a preferred embodiment of the present invention and is not intended to limit 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 temperature-sensitive film, characterized in that: include: An adhesive layer (2), on which an insulating layer (3) is provided, and a temperature-sensitive layer (4) is provided on the insulating layer (3); The adhesion layer (2) is made of NiCrAlY material, the insulation layer (3) is made of high melting point metal oxide material, and the temperature sensitive layer (4) is an ITO-Al2O3 composite film with a mass ratio of Al to In of 1-10wt%.

2. A temperature-sensitive film according to claim 1, characterized in that: The thickness of the adhesion layer (2) is 5-30 μm.

3. The temperature-sensitive film according to claim 1, characterized in that: The insulating layer (3) is made of Al2O3, CeO2 or HfO2 material.

4. The temperature-sensitive film according to claim 1, characterized in that: The thickness of the insulating layer (3) is 2-4 μm.

5. The temperature-sensitive film according to claim 1, characterized in that: The thickness of the temperature-sensitive layer (4) is 1-10 μm.

6. A method for preparing a temperature-sensitive thin film based on sputtering technology, characterized in that: include: An adhesion layer (2) is sputtered on a component to be tested (1) using a NiCrAlY target material with a purity of 99.99% in a magnetron sputtering machine; sputtering an insulating layer (3) on the adhesion layer (2) using a metal oxide target; Coating a photoresist on the surface of the insulating layer (3), performing UV exposure using a mask, developing, and performing photolithography on the insulating layer (3) coated with the photoresist to obtain a patterned area of ​​the temperature-sensitive layer (4); An ITO-Al2O3 doped target or an ITO and Al2O3 dual target is sputtered in a patterned area of ​​the temperature-sensitive layer (4) to prepare an ITO-Al2O3 composite film of 1-10 μm; and the photoresist is cleaned and dried to obtain the temperature-sensitive film.

7. The method for preparing a temperature-sensitive thin film based on sputtering technology according to claim 6, characterized in that: The photoresist is coated on the surface of the insulating layer (3) by using a spin coating technique.

8. The method for preparing a temperature-sensitive thin film based on sputtering technology according to claim 6, characterized in that: UV exposure and development were performed using a serpentine gate mask.

9. The method for preparing a temperature-sensitive thin film based on sputtering technology according to claim 6, characterized in that: Based on magnetron sputtering technology, an ITO-Al2O3 doped target material or an ITO and Al2O3 dual target material is sputtered and deposited in the patterned area of ​​the temperature-sensitive layer (4) to form an ITO-Al2O3 composite film.

10. A thin film temperature sensor, characterized in that: include: The temperature-sensitive film according to claims 1 to 5, wherein the adhesive layer (2) of the temperature-sensitive film is used to adhere to the component to be measured (1), and the temperature-sensitive layer (4) of the temperature-sensitive film leads out a platinum wire to transmit an electrical signal.

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