Film platinum resistor temperature sensor

Abstract

The invention discloses a film platinum resistor temperature sensor, which comprises an aluminum oxide insulating substrate, a titanium film, a platinum film resistor layer, a protective layer, a platinum metal lead and encapsulating slurry, the titanium thin film is deposited on the surface of the aluminum oxide insulating substrate, the platinum thin film resistance layer is deposited on the surface of the titanium thin film, the protection layer is deposited on the surface of the platinum thin film resistance layer, the platinum metal lead is welded on a bonding pad on the platinum thin film resistance layer, and the packaging slurry is coated on the protection layer and the platinum thin film resistance layer. According to the invention, the platinum film temperature sensor with high precision, good consistency, wide temperature measurement range and strong stability is obtained through arrangement and allocation of a multi-layer structure.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of temperature measurement, in particular to a thin-film platinum resistance temperature sensor. BACKGROUND

[0002] The thin-film platinum resistance temperature sensor is a temperature measuring element prepared by using the temperature characteristics of platinum, i.e. the linear change of the resistance value with temperature. The traditional platinum resistance temperature sensor is prepared by winding a high-purity platinum wire on an insulating framework, but the temperature sensor prepared in this way is large in size, slow in response and high in cost, and is gradually eliminated in various temperature measurement and control scenes. On the contrary, the thin-film platinum resistance temperature sensor is widely used in temperature measurement and control systems in various fields due to the advantages of small size, high precision, good linearity and strong stability. However, it is not a simple work to obtain a temperature sensor with high precision, high sensitivity, high stability and wide temperature measurement range due to the influence of factors such as the complex thin-film preparation process, the matching between different materials and the consistency of laser resistance adjustment. SUMMARY

[0003] The purpose of the application is to provide a thin-film platinum resistance temperature sensor which has the characteristics of high precision, high sensitivity, high stability and wide temperature measurement range through a series of packaging processes.

[0004] The technical scheme of the application provides a thin-film platinum resistance temperature sensor, which comprises:

[0005] an alumina insulating substrate, a titanium thin film, a platinum thin film resistance layer, a protective layer, a solder pad, a platinum metal lead and a sealing paste.

[0006] The titanium thin film is deposited on the surface of the alumina insulating substrate and serves as an adhesion layer to improve the bonding force between the platinum thin film resistance layer and the alumina insulating substrate; the platinum thin film resistance layer is deposited on the surface of the titanium thin film; the protective layer is deposited on the surface of the platinum thin film resistance layer; the platinum metal lead is welded on the solder pad on the platinum thin film resistance layer; and the sealing paste is wrapped around the protective layer and the platinum thin film resistance layer.

[0007] Further, the material of the protective layer is alumina or silicon dioxide.

[0008] Further, the purity of the alumina insulating substrate is greater than 99%, the thickness is 0.6 mm, and the single-throw roughness is less than 0.05 microns.

[0009] Further, the thickness of the titanium thin film is in the range of 20-50 nm.

[0010] Further, the thickness of the platinum thin film resistance layer is in the range of 1-5 microns.

[0011] Further, the thickness of the protective layer is in the range of 1-3 microns, which is beneficial to improve the long-term stability of the temperature sensor.

[0012] Further, the length of the platinum metal lead is 1 cm.

[0013] Further, the encapsulating slurry layer is glass powder, and the main components of the glass powder are CaO-Al2O3-SiO2, and the sintering temperature is 850 DEG C.

[0014] Compared with the prior art, the thin-film platinum resistance temperature sensor has the following technical effects:

[0015] The thin-film platinum resistance temperature sensor provided by the application can improve the bonding force between the thin-film resistance and the substrate by depositing a titanium thin film as an adhesion layer on the clean and smooth surface of the substrate. A layer of alumina or silicon dioxide is deposited on the prepared platinum thin film pattern, and the thermal expansion coefficient of the alumina insulating substrate is matched, so that the thermal stress between the layers can be reduced, and the stress generated by the encapsulating slurry directly contacting the platinum thin film during the sintering process or the damage of the platinum thin film resistance by metal elements can be prevented, thereby ensuring the long-term stability of the thin-film platinum resistance temperature sensor in the temperature measurement range. In addition, a layer of encapsulating slurry with high temperature resistance, good wrapping property, good mechanical property and insulation is coated on the protective layer and the pad lead, and a series of packaging processes can prevent the platinum thin film resistance from being affected by the external environment. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 is the overall structure diagram of the application.

[0017] Figure 2 is the R-T test curve diagram in the embodiment of the application.

[0018] Label description: 1-alumina insulating substrate, 2-titanium thin film, 3-platinum thin film resistance layer, 4-protective layer, 5-pad, 6-platinum metal lead and 7-encapsulating slurry. DETAILED DESCRIPTION

[0019] It should be noted that when an element is referred to as being "on" another element, it can be directly on the other element or intervening elements can also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements can also be present. The terms "vertical", "horizontal", "left", "right" and similar expressions as used herein are for illustration only and do not indicate the only orientation of the embodiments.

[0020] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items. The technical solutions in the embodiments of the present invention have been clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without inventive effort are within the scope of protection of the present invention.

[0021] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0022] To achieve the above objectives, this invention proposes a thin-film platinum resistance temperature sensor, such as... Figure 1 As shown, it includes:

[0023] 1. Alumina insulating substrate; 2. Titanium thin film; 3. Platinum thin film resistive layer; 4. Protective layer; 5. Platinum metal lead wire; 6. Encapsulation paste; 7.

[0024] The titanium thin film 2 is deposited on the surface of the alumina insulating substrate 1, serving as an adhesion layer to improve the bonding force between the platinum thin film resistive layer 3 and the alumina insulating substrate 1; the platinum thin film resistive layer 3 is deposited on the surface of the titanium thin film 2; the protective layer 4 is deposited on the surface of the platinum thin film resistive layer 3; the platinum metal lead 6 is soldered to the pad 5 on the platinum thin film resistive layer 3; and the encapsulating paste 7 covers the protective layer 4 and the platinum thin film resistive layer 3 around its perimeter.

[0025] The fabrication method of the thin-film platinum resistance temperature sensor is as follows:

[0026] S1. Before the coating process begins, the alumina insulating substrate 1 is ultrasonically cleaned using isopropanol, ethanol, and deionized water, respectively, to ensure the quality of the coating. The alumina insulating substrate 1 has a purity greater than 99%, a thickness of 0.6 mm, and a single-polish roughness of less than 0.05 μm.

[0027] S2. A titanium thin film 2 is deposited on the surface of an alumina insulating substrate 1 using a magnetron sputtering device, serving as an adhesion layer to improve the bonding force between the platinum thin film resistive layer 3 and the alumina insulating substrate 1. The thickness of the titanium thin film 2 is in the range of 20nm-50nm.

[0028] S3. A platinum thin-film resistive layer 3 is deposited on the surface of the titanium thin film 2 using magnetron sputtering equipment. The resulting platinum thin-film resistive layer 3 is then annealed in a high-temperature furnace under argon protection at 900℃-1200℃ to eliminate film stress and improve film stability. After annealing, the platinum thin-film resistive layer 3 is subjected to photolithography and ion beam etching processes to obtain a pre-designed platinum thin-film resistive pattern. The thickness of the platinum thin-film resistive layer 3 is in the range of 1μm-5μm.

[0029] S4. A protective layer 4 is deposited on the surface of the platinum thin-film resistive layer 3 using magnetron sputtering equipment. The main purpose is to prevent the encapsulating paste 7 from affecting the platinum thin-film resistive layer 3. The protective layer 4 is made of alumina or silicon dioxide, which has a similar coefficient of thermal expansion to the alumina insulating substrate 1, to reduce thermal stress between layers. After deposition, the protective layer 4 is annealed at 800°C to make it more stable. The thickness of the protective layer 4 is in the range of 1μm-3μm.

[0030] S5. Solder the platinum metal lead 6 onto the pad 5 on the platinum thin film resistive layer 3. The length of the platinum metal lead 6 is 1 cm.

[0031] S6. The encapsulating slurry 7 is coated onto the protective layer 4 and the platinum thin-film resistive layer 3, dried at 120°C, and then sintered in a high-temperature furnace at 850°C. The encapsulating slurry 7 is a sintering slurry with a sintering temperature of 850°C, ensuring that the temperature sensor can operate normally at temperatures up to 500°C. The encapsulating slurry 7 not only reinforces the leads, allowing them to withstand a tensile force of at least 10N, but also, due to its high temperature resistance, good encapsulation properties, good mechanical properties, and insulation, ensures that the temperature sensor is unaffected by external factors when operating within its operating temperature range.

[0032] The thin-film platinum resistance temperature sensor prepared according to this invention was tested under different temperature conditions, and the test results are as follows: Figure 2 As shown, within the temperature range of -50℃ to 500℃, the thin-film platinum resistance temperature sensor exhibits a good linear relationship between temperature and resistance, and the error between the actual resistance value and the theoretical resistance value is within the allowable range of the technical specifications. The technical parameters of this sensor meet the requirements of a Class A platinum resistance temperature sensor, specifically: a temperature coefficient of (3850±5)ppm / ℃, a resistance error of ±0.06% at zero degrees, and a temperature measurement range of -70 to 500℃.

[0033] Therefore, the thin-film platinum resistance temperature sensor prepared in this invention possesses advantages such as high accuracy, good consistency, wide temperature measurement range, and strong stability. Based on the resistance-temperature characteristics of platinum, this sensor reflects changes in ambient temperature by measuring changes in resistance, playing a crucial role in the industrial field and providing reliable temperature monitoring and control for various applications. The thin-film platinum resistance temperature sensor can operate stably in both extremely cold and extremely hot environments, providing accurate temperature data. Therefore, it can be widely used in industrial control, environmental monitoring, medical equipment, and many other fields, providing important technical support for various sectors of modern society.

[0034] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A thin-film platinum resistance temperature sensor, characterized by, The application relates to a platinum thin film resistor, which comprises an alumina insulating substrate (1), a titanium thin film (2), a platinum thin film resistor layer (3), a protective layer (4), a platinum metal lead (6) and a sealing paste (7). The titanium thin film (2) is deposited on the surface of the alumina insulating substrate (1); the platinum thin film resistor layer (3) is deposited on the surface of the titanium thin film (2); the protective layer (4) is deposited on the surface of the platinum thin film resistor layer (3); the platinum metal lead (6) is welded on the pad (5) on the platinum thin film resistor layer (3); and the sealing paste (7) is coated around the protective layer (4) and the platinum thin film resistor layer (3). The material of the protective layer (4) is alumina or silicon dioxide.

2. The thin-film platinum resistance temperature sensor of claim 1, wherein, The purity of the alumina insulating substrate (1) is greater than 99%, the thickness is 0.6 mm, and the single-throw roughness is lower than 0.05 mu m.

3. The thin-film platinum resistance temperature sensor of claim 1, wherein, The thickness of the titanium thin film (2) is in the range of 20 nm-50 nm.

4. The thin-film platinum resistance temperature sensor of claim 1, wherein, The thickness of the platinum thin film resistor layer (3) is in the range of 1 mu m-5 mu m.

5. The thin-film platinum resistance temperature sensor of claim 1, wherein, The thickness of the protective layer (4) is in the range of 1 mu m-3 mu m.

6. The thin-film platinum resistance temperature sensor of claim 1, wherein, The length of the platinum metal lead (6) is 1 cm.

7. The thin-film platinum resistance temperature sensor of claim 1, wherein, The sealing paste (7) is glass powder, the main component of the glass powder is CaO-Al2O3-SiO2, and the sintering temperature is 850 DEG C.

8. The thin-film platinum resistance temperature sensor of claim 1, wherein, ​

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