Corrosion-resistant, high-thermal-conductivity epoxy-encapsulated metal film sensor

Abstract

The utility model relates to a kind of corrosion-resistant, high heat-conducting epoxy encapsulated metal film sensor, it belongs to temperature measurement field.The utility model aims to solve the problem of poor protection of metal film sensor glass paste sintering and the performance index of sensor is reduced, the problem of reduced work reliability caused by secondary packaging.A kind of corrosion-resistant, high heat-conducting epoxy encapsulated metal film sensor, including high heat-conducting substrate, metal film resistance, glass sealing layer, wire and high heat-conducting epoxy encapsulation, and form integrated structure.The utility model uses the integrated packaging of corrosion-resistant, high heat-conducting, improves the corrosion resistance and heat conduction characteristics of sensor, enhances the environmental adaptability, response characteristic of sensor, satisfies more field temperature measurement application;The design of the utility model two high heat-conducting protective layers significantly improves the environmental performance and response characteristic of sensor;Product does not need to carry out secondary packaging protection isolation environment to carry out temperature measurement, application cost is significantly reduced while performance is improved.

Description

Technical Field

[0001] This utility model belongs to the field of temperature measurement, specifically relating to a corrosion-resistant, high thermal conductivity epoxy-encapsulated metal thin film sensor. Background Technology

[0002] Temperature sensors are widely used in industrial production, environmental monitoring, and life sciences to measure temperatures in the environment, equipment, control systems, and health, thereby guiding people's production and daily life. They are one of the most important types of sensors. Currently, temperature sensors can be classified according to their working principle into thermocouples, thermistors (NTC, PTC), and metal resistance thermometers (RTDs). Among these, metal thin-film sensors have advantages such as small size, high temperature measurement accuracy, and good stability, and are widely used in many industries. After nearly a century of technological development, metal thin-film sensors have evolved into products based on Pt, Cu, and Ni materials. The temperature-sensing film protection is achieved by sintering glass slurry to form a 20-40μm protective layer. However, the disadvantage of glass sintering encapsulation is that the brittleness of glass can lead to damage to the protective layer, resulting in decreased product performance or even failure. Furthermore, the poor density of the sintered glass slurry results in poor corrosion resistance, further affecting product performance. Existing thin-film metal sensors require secondary encapsulation to improve environmental tolerance and ensure performance. This method involves encapsulating the sensor within a housing and soldering the leads to the insulating wire and enameled wire to extract the signal, resulting in a complex process and increased design and production costs. Furthermore, the secondary encapsulation structure reduces thermal conductivity, slowing down the sensor's response speed and hindering its widespread adoption. Utility Model Content

[0003] The purpose of this invention is to solve the problems of poor protection during the sintering of glass slurry in metal thin film sensors and the resulting decline in sensor performance and reduced reliability due to secondary encapsulation, and to provide a corrosion-resistant, high thermal conductivity epoxy-encapsulated metal thin film sensor.

[0004] A corrosion-resistant, high thermal conductivity epoxy-encapsulated metal thin film sensor includes a high thermal conductivity substrate 1, a metal thin film resistor 2, a glass sealing layer 3, a wire 4, and a high thermal conductivity epoxy encapsulation 5, which are integrated into a single structure.

[0005] The high thermal conductivity substrate 1 is made of aluminum nitride and has a thickness of 0.15~0.5mm;

[0006] The metal thin film resistor 2 includes a temperature-sensing resistor strip 2-1, a resistance-adjusting resistor strip 2-2, pad 1 2-3, pad 2-4, solder 1 2-5, and solder 2-6;

[0007] One end of the temperature-sensing resistor strip 2-1 is connected to pad 2-3 of number 1, and the other end of the temperature-sensing resistor strip 2-1 is connected to pad 2-4 of number 2. The resistance adjustment resistor strip 2-2 is connected in series with the temperature-sensing resistor strip 2-1. Solder 2-5 of number 1 is attached to the upper surface of pad 2-3, and solder 2-6 of number 2 is attached to the upper surface of pad 2-4 of number 2.

[0008] The glass sealing layer 3 includes a glass layer 3-1 and a cut resistor strip 3-2; the glass layer 3-1 is formed by sintering glass slurry, completely covering the temperature-sensing resistor strip 2-1, but not covering the resistance adjustment resistor strip 2-2, pad 1 2-3, pad 2-4, solder 1 2-5, and solder 2-6; the resistance adjustment resistor strip 2-2 is cut using laser trimming to form the cut resistor strip 3-2;

[0009] The wire 4 includes wire 4-1 and wire 4-2; wire 4-1 is connected to solder 2-5, and wire 4-2 is connected to solder 2-6 to form an electrical conductive structure.

[0010] The high thermal conductivity epoxy encapsulation 5 includes a thermally conductive silicone layer 5-1 with a thermal conductivity better than 2.0 W / (m·K) and an epoxy resin encapsulation layer 5-2 with a thermal conductivity better than 0.4 W / (m·K); the thermally conductive silicone layer 5-1 completely covers the solder joints of the high thermal conductivity substrate 1, the metal thin film resistor 2, the glass sealing layer 3, and the wire 4; the epoxy resin encapsulation layer 5-2 is disposed above the thermally conductive silicone layer 5-1, completely covering the thermally conductive silicone layer 5-1, forming an integrated metal thin film sensor structure.

[0011] The principle and advantages of this utility model:

[0012] I. To address the aforementioned technical challenges, this invention employs high thermal conductivity epoxy encapsulation technology to protect the aluminum nitride substrate, temperature-sensing metal thin-film resistor, and solder joints, forming a corrosion-resistant, high thermal conductivity integrated encapsulation structure. The wires are connected to the solder pads using enameled wire or insulated wire. The developed epoxy-encapsulated metal thin-film sensor eliminates the need for lead wire soldering and solder joint protection during application, significantly reducing operating costs. Simultaneously, the corrosion-resistant, high thermal conductivity integrated encapsulation enhances the sensor's corrosion resistance and thermal conductivity, improving its environmental adaptability and response characteristics, thus meeting the needs of temperature measurement applications in a wider range of fields.

[0013] II. This utility model employs a two-layer high thermal conductivity epoxy encapsulation technology. First, high thermal conductivity silicone is used to coat the aluminum nitride substrate, metal thin-film resistor, and solder joints, forming the first thermally conductive protective layer. Then, high thermal conductivity epoxy resin is applied to form the second thermally conductive protective layer. This two-layer design significantly improves the sensor's environmental resistance and response characteristics. The product eliminates the need for secondary encapsulation and environmental isolation for temperature measurement, resulting in significantly reduced application costs while improving performance.

[0014] Third, this utility model adopts the technology of combining semiconductor and thick film, which can realize the mass production of products, and the production efficiency and cost can be effectively controlled. The developed metal thin film sensor has a significant competitive advantage in the field of temperature measurement.

[0015] This invention provides a corrosion-resistant, high thermal conductivity epoxy-encapsulated metal thin-film sensor. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the layered structure of a corrosion-resistant, high thermal conductivity epoxy-encapsulated metal thin-film sensor according to this utility model.

[0017] Figure 2 This is a schematic diagram of an epoxy-encapsulated metal thin-film sensor with corrosion resistance and high thermal conductivity according to this utility model. Detailed Implementation

[0018] Specific implementation method one: This implementation method is a corrosion-resistant, high thermal conductivity epoxy-encapsulated metal thin film sensor, including a high thermal conductivity substrate 1, a metal thin film resistor 2, a glass sealing layer 3, a wire 4, and a high thermal conductivity epoxy encapsulation 5, which form an integral structure;

[0019] The high thermal conductivity substrate 1 is made of aluminum nitride and has a thickness of 0.15~0.5mm;

[0020] The metal thin film resistor 2 includes a temperature-sensing resistor strip 2-1, a resistance-adjusting resistor strip 2-2, pad 1 2-3, pad 2-4, solder 1 2-5, and solder 2-6;

[0021] One end of the temperature-sensing resistor strip 2-1 is connected to pad 2-3 of number 1, and the other end of the temperature-sensing resistor strip 2-1 is connected to pad 2-4 of number 2. The resistance adjustment resistor strip 2-2 is connected in series with the temperature-sensing resistor strip 2-1. Solder 2-5 of number 1 is attached to the upper surface of pad 2-3, and solder 2-6 of number 2 is attached to the upper surface of pad 2-4 of number 2.

[0022] The glass sealing layer 3 includes a glass layer 3-1 and a cut resistor strip 3-2; the glass layer 3-1 is formed by sintering glass slurry, completely covering the temperature-sensing resistor strip 2-1, but not covering the resistance adjustment resistor strip 2-2, pad 1 2-3, pad 2-4, solder 1 2-5, and solder 2-6; the resistance adjustment resistor strip 2-2 is cut using laser trimming to form the cut resistor strip 3-2;

[0023] The wire 4 includes wire 4-1 and wire 4-2; wire 4-1 is connected to solder 2-5, and wire 4-2 is connected to solder 2-6 to form an electrical conductive structure.

[0024] The high thermal conductivity epoxy encapsulation 5 includes a thermally conductive silicone layer 5-1 with a thermal conductivity better than 2.0 W / (m·K) and an epoxy resin encapsulation layer 5-2 with a thermal conductivity better than 0.4 W / (m·K); the thermally conductive silicone layer 5-1 completely covers the solder joints of the high thermal conductivity substrate 1, the metal thin film resistor 2, the glass sealing layer 3, and the wire 4; the epoxy resin encapsulation layer 5-2 is disposed above the thermally conductive silicone layer 5-1, completely covering the thermally conductive silicone layer 5-1, forming an integrated metal thin film sensor structure.

[0025] Specific Implementation Method Two: This implementation method differs from Specific Implementation Method One in that the surface roughness of the high thermal conductivity substrate 1 is better than 25 nm, and the thermal conductivity is higher than 230 W / (m·K). The other steps are the same as in Specific Implementation Method One.

[0026] Specific Implementation Method Three: This implementation method differs from Specific Implementation Method One or Two in that: the No. 1 conductor 4-1 and the No. 2 conductor 4-2 are enameled wires or sheathed wires. The other steps are the same as in Specific Implementation Method One or Two.

[0027] Specific Implementation Method Four: This implementation method differs from Specific Implementation Methods One to Three in that the temperature-sensing resistor strip 2-1, the resistance adjustment resistor strip 2-2, pad 1 2-3, and pad 2-4 are Cu thin films, Ni thin films, or Pt thin films. The other steps are the same as in Specific Implementation Methods One to Three.

[0028] Specific Implementation Method Five: This implementation method differs from Specific Implementation Methods One to Four in that the thickness of the film is 1.0~2.0μm. The other steps are the same as in Specific Implementation Methods One to Four.

[0029] Specific Implementation Method Six: This implementation method differs from Specific Implementation Methods One to Five in that: the No. 1 solder 2-5 and No. 2 solder 2-6 are the same, and the solder is Ag paste, Ag-Pd paste, or Pt paste. Other steps are the same as in Specific Implementation Methods One to Five.

[0030] Specific Implementation Method Seven: The difference between this implementation method and Specific Implementation Methods One to Six is ​​that the cutting of the resistor strip 3-2 adjusts the resistance value of the metal thin film sensor. The resistance value of the metal thin film sensor can be 20Ω, 100Ω, 200Ω, 500Ω, 1000Ω, 5000Ω, or 10000Ω. The other steps are the same as in Specific Implementation Methods One to Six.

[0031] The beneficial effects of this utility model are verified by the following embodiments:

[0032] Example 1: A corrosion-resistant, high thermal conductivity epoxy-encapsulated metal thin film sensor, comprising a high thermal conductivity substrate 1, a metal thin film resistor 2, a glass sealing layer 3, a wire 4, and a high thermal conductivity epoxy encapsulation 5, forming an integral structure;

[0033] The high thermal conductivity substrate 1 is made of aluminum nitride and has a thickness of 0.5 mm.

[0034] The metal thin film resistor 2 includes a temperature-sensing resistor strip 2-1, a resistance-adjusting resistor strip 2-2, pad 1 2-3, pad 2-4, solder 1 2-5, and solder 2-6;

[0035] One end of the temperature-sensing resistor strip 2-1 is connected to pad 2-3 of number 1, and the other end of the temperature-sensing resistor strip 2-1 is connected to pad 2-4 of number 2. The resistance adjustment resistor strip 2-2 is connected in series with the temperature-sensing resistor strip 2-1. Solder 2-5 of number 1 is attached to the upper surface of pad 2-3, and solder 2-6 of number 2 is attached to the upper surface of pad 2-4 of number 2.

[0036] The glass sealing layer 3 includes a glass layer 3-1 and a cut resistor strip 3-2; the glass layer 3-1 is formed by sintering glass slurry, completely covering the temperature-sensing resistor strip 2-1, but not covering the resistance adjustment resistor strip 2-2, pad 1 2-3, pad 2-4, solder 1 2-5, and solder 2-6; the resistance adjustment resistor strip 2-2 is cut using laser trimming to form the cut resistor strip 3-2;

[0037] The wire 4 includes wire 4-1 and wire 4-2; wire 4-1 is connected to solder 2-5, and wire 4-2 is connected to solder 2-6 to form an electrical conductive structure.

[0038] The high thermal conductivity epoxy encapsulation 5 includes a thermally conductive silicone layer 5-1 with a thermal conductivity better than 2.0 W / (m·K) and an epoxy resin encapsulation layer 5-2 with a thermal conductivity better than 0.4 W / (m·K); the thermally conductive silicone layer 5-1 completely covers the solder joints of the high thermal conductivity substrate 1, the metal thin film resistor 2, the glass sealing layer 3, and the wire 4; the epoxy resin encapsulation layer 5-2 is disposed above the thermally conductive silicone layer 5-1, completely covering the thermally conductive silicone layer 5-1, forming an integrated metal thin film sensor structure;

[0039] Furthermore, the surface roughness of the high thermal conductivity substrate 1 is better than 25 nm, and the thermal conductivity is higher than 230 W / (m·K);

[0040] Furthermore, the No. 1 wire 4-1 and the No. 2 wire 4-2 are enameled wires, which are connected to the No. 1 solder 2-5 and the No. 2 solder 2-6 respectively by resistance welding using existing technology;

[0041] Furthermore, the temperature-sensing resistor strip 2-1, the resistance adjustment resistor strip 2-2, pad 1 2-3, and pad 2-4 are Cu thin films with a thickness of 1.5 μm; they are prepared using existing magnetron sputtering technology, with a Cu target of higher purity than 99.99%, a sputtering power of 1500 W, a sputtering time of 40 min, an Ar sputtering gas of higher purity than 99.99%, and a sputtering pressure of 0.15 Pa.

[0042] Furthermore, the No. 1 solder 2-5 and No. 2 solder 2-6 are the same, and the solder is Ag-Pd paste. It is attached to No. 1 solder pad 2-3 and No. 2 solder pad 2-4 by existing screen printing technology. After sintering at 850℃ for 12 minutes, it is connected to No. 1 solder pad 2-3 and No. 2 solder pad 2-4 respectively to form an electrically conductive structure.

[0043] Furthermore, the glass layer 3-1 is formed by sintering glass slurry at 950°C for 15 minutes; the cut resistor strip 3-2 adjusts the resistance value of the metal thin film sensor so that the output resistance value of the metal thin film sensor is 100Ω.

[0044] The resistance values ​​at 0℃ and 100℃ of the corrosion-resistant, high thermal conductivity epoxy-encapsulated metal thin-film sensor described in Example 1 are shown in Table 1; the resistance at 0℃ is controlled at 100.00±0.04Ω, and the resistance at 100℃ is controlled at 142.80±0.08Ω, with a temperature coefficient of (4280±2.3)×10. -6 / ℃, which is better than the international standard, with high temperature measurement accuracy and good consistency.

[0045] Table 1

[0046]

Claims

1. A corrosion-resistant, high thermal conductivity epoxy-encapsulated metal thin-film sensor, characterized in that... The corrosion-resistant, high thermal conductivity epoxy-encapsulated metal thin film sensor includes a high thermal conductivity substrate (1), a metal thin film resistor (2), a glass sealing layer (3), a wire (4), and a high thermal conductivity epoxy encapsulation (5), forming an integral structure; The high thermal conductivity substrate (1) is made of aluminum nitride and has a thickness of 0.15~0.5mm; The metal thin film resistor (2) includes a temperature sensing resistor strip (2-1), a resistance adjustment resistor strip (2-2), pad 1 (2-3), pad 2 (2-4), solder 1 (2-5), and solder 2 (2-6). One end of the temperature-sensing resistor strip (2-1) is connected to pad 1 (2-3), and the other end of the temperature-sensing resistor strip (2-1) is connected to pad 2 (2-4). The resistance adjustment resistor strip (2-2) is connected in series with the temperature-sensing resistor strip (2-1). Solder No. 1 (2-5) is attached to the upper surface of pad 1 (2-3), and solder No. 2 (2-6) is attached to the upper surface of pad 2 (2-4). The glass sealing layer (3) includes a glass layer (3-1) and a cut resistor strip (3-2); the glass layer (3-1) is formed by sintering glass slurry, completely covering the temperature-sensing resistor strip (2-1), but not covering the resistance adjustment resistor strip (2-2), pad 1 (2-3), pad 2 (2-4), solder 1 (2-5), and solder 2 (2-6); the resistance adjustment resistor strip (2-2) is cut using laser trimming to form the cut resistor strip (3-2); The wire (4) includes wire 1 (4-1) and wire 2 (4-2); wire 1 (4-1) is connected to solder 1 (2-5), and wire 2 (4-2) is connected to solder 2 (2-6) to form an electrical conduction structure; The high thermal conductivity epoxy encapsulation (5) includes a thermally conductive silicone layer (5-1) with a thermal conductivity better than 2.0 W / (m·K) and an epoxy resin encapsulation layer (5-2) with a thermal conductivity better than 0.4 W / (m·K); the thermally conductive silicone layer (5-1) completely covers the solder joints of the high thermal conductivity substrate (1), the metal thin film resistor (2), the glass sealing layer (3), and the wire (4); the epoxy resin encapsulation layer (5-2) is disposed above the thermally conductive silicone layer (5-1) and completely covers the thermally conductive silicone layer (5-1) to form an integrated metal thin film sensor.

2. The corrosion-resistant, high thermal conductivity epoxy-encapsulated metal thin-film sensor according to claim 1, characterized in that... The surface roughness of the high thermal conductivity substrate (1) is better than 25 nm, and the thermal conductivity is higher than 230 W / (m·K).

3. The corrosion-resistant, high thermal conductivity epoxy-encapsulated metal thin-film sensor according to claim 1, characterized in that... The first conductor (4-1) and the second conductor (4-2) are enameled wires or sheathed wires.

4. The corrosion-resistant, high thermal conductivity epoxy-encapsulated metal thin-film sensor according to claim 1, characterized in that... The temperature-sensing resistor strip (2-1), resistance adjustment resistor strip (2-2), pad 1 (2-3), and pad 2 (2-4) are Cu thin films, Ni thin films, or Pt thin films.

5. A corrosion-resistant, high thermal conductivity epoxy-encapsulated metal thin-film sensor according to claim 4, characterized in that... The thickness of the film is 1.0~2.0μm.

6. A corrosion-resistant, high thermal conductivity epoxy-encapsulated metal thin-film sensor according to claim 1, characterized in that... The No. 1 solder (2-5) and No. 2 solder (2-6) mentioned above are the same, and the solder is Ag paste, Ag-Pd paste or Pt paste.

7. A corrosion-resistant, high thermal conductivity epoxy-encapsulated metal thin-film sensor according to claim 1, characterized in that... The cutting resistor strip (3-2) adjusts the resistance value of the metal thin film sensor. The resistance value of the metal thin film sensor can be 20Ω, 100Ω, 200Ω, 500Ω, 1000Ω, 5000Ω, or 10000Ω.

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