Low-temperature vacuum packaging structure of biosensor

Abstract

The utility model discloses a low-temperature vacuum packaging structure of a biosensor, and relates to the field of sensor packaging. The sensor comprises a flexible substrate, a polymer film is arranged on the surface of the flexible substrate, an air suction layer is arranged on the side, facing the flexible substrate, of the polymer film, a vacuum packaging cavity is formed between the polymer film and the surface of the sensor, a metal shell is arranged on the side, deviating from the flexible substrate, of the polymer film, and the metal shell is welded to the polymer film. Moisture and oxygen are effectively isolated, and the long-term stability of the sensor is kept.

Description

Technical Field

[0001] This application relates to the field of sensor packaging, and in particular to a low-temperature vacuum packaging structure for a biosensor. Background Technology

[0002] CGM stands for Continuous Glucose Monitoring. A CGM biosensor is a biosensor used in dynamic blood glucose monitoring systems, which is a medical device used to monitor glucose levels in diabetic patients in real time.

[0003] To reduce the impact of moisture on CGM biosensors, a UV coating is typically applied to the surface of the CGM biosensor to provide insulation and protection.

[0004] However, some biosensors require the detection end to be implanted in the human body, while the biosensor substrate is attached to the skin. The substrate needs to adapt to high temperature and high humidity environments along with the human body. With the traditional UV coating encapsulation method, moisture and heat can easily penetrate the UV coating, affecting the substrate and thus reducing the sensor performance. Utility Model Content

[0005] In order to effectively isolate moisture and oxygen and maintain the long-term stability of the sensor, this application provides a low-temperature vacuum packaging structure for a biosensor.

[0006] The low-temperature vacuum packaging structure for a biosensor provided in this application adopts the following technical solution:

[0007] A low-temperature vacuum encapsulation structure for a biosensor includes a flexible substrate, a polymer film on the surface of the flexible substrate, an air-absorbing layer on the side of the polymer film facing the flexible substrate, a vacuum encapsulation cavity formed between the polymer film and the surface of the flexible substrate, and a metal shell on the side of the polymer film away from the flexible substrate, the metal shell being welded to the polymer film.

[0008] By adopting the above technical solution, the vacuum and low-temperature environment effectively isolates moisture and oxygen, ensuring strong airtightness, maintaining the long-term stability and measurement accuracy of the sensor, and extending its service life. Furthermore, due to its effective isolation from the influence of the external environment, low-temperature vacuum packaging is particularly suitable for sensors with high precision and long-term stability requirements, making the sensor more durable.

[0009] Optionally, the welding layer between the metal casing and the polymer film is an intermetallic compound layer.

[0010] By adopting the above technical solution, the intermetallic compound layer exhibits excellent hermeticity, effectively isolating moisture and oxygen in a vacuum environment, thereby ensuring the stability of the sensor during long-term storage and transportation. This welding layer not only improves the overall robustness of the package but also effectively resists external physical impacts, ensuring the reliable performance of the sensor under various environmental conditions. The formation of the intermetallic compound layer makes the microstructure at the welding interface more compact, reducing the generation of voids and defects, which helps to improve the long-term stability and reliability of the packaged components.

[0011] Optionally, the intermetallic compound layer is a Cu3Sn layer or a Cu6Sn5 layer.

[0012] By adopting the above technical solution, the mechanical strength and airtightness of the welding interface are improved, ensuring that the low-temperature vacuum packaging structure of the biosensor maintains stable performance during long-term storage and transportation.

[0013] Optionally, the polymer film is a polyimide film.

[0014] By adopting the above technical solution, the polyimide film, as a polymer film material, possesses extremely high mechanical strength and tear resistance, providing excellent physical protection. Simultaneously, the excellent airtightness and chemical stability of the polyimide film ensure that the biosensor remains stable over a long period in environments with high humidity and large temperature fluctuations, effectively preventing the intrusion of moisture and oxygen, thereby improving the sensor's measurement accuracy and lifespan.

[0015] Optionally, the air-absorbing layer is a low-temperature activated metal oxide layer.

[0016] By employing the above technical solution, the low-temperature activated metal oxide layer possesses a high specific surface area and excellent adsorption performance, enabling it to rapidly capture and absorb trace amounts of moisture and oxygen within the encapsulation cavity, ensuring a highly dry and pure internal environment. Simultaneously, the low-temperature activated metal oxide layer helps prevent the degradation of enzyme membranes and other sensitive elements of the biosensor due to moisture and oxygen, significantly extending the sensor's lifespan.

[0017] Optionally, the low-temperature activated metal oxide layer is a zirconium oxide layer or a titanium oxide layer.

[0018] By adopting the above technical solutions, these materials exhibit excellent chemical stability and mechanical properties in low-temperature environments (2℃-8℃), and can maintain their adsorption capacity for a long time, reducing the degradation of sensor performance caused by environmental changes.

[0019] Optionally, one end of the flexible substrate is connected to a working electrode, and a reference electrode and a counter electrode are provided on the surface of the flexible substrate. The reference electrode and the counter electrode are exposed outside the vacuum packaging cavity, and the working electrode and the counter electrode form a polarization circuit.

[0020] By adopting the above technical solution, the working electrode, as the detection end, is implanted into the human body, and the working electrode and the counter electrode form a polarization circuit. The reference electrode potential is not affected by polarization and remains at a constant value, ensuring the stability of the working electrode potential.

[0021] Optionally, the flexible substrate is made of polyethylene terephthalate or polyimide; the reference electrode is made of silver chloride or saturated calomel electrode; and the working electrode is made of platinum, glassy carbon, carbon nanotubes, ordinary biochar, poly(3,4-ethylenedioxythiophene), or polyethylene nitride.

[0022] By adopting the above technical solutions, the flexible substrate is made of polyethylene terephthalate or polyimide, which provides good mechanical properties and chemical resistance, making it suitable for long-term storage and transportation. The reference electrode is made of silver chloride or saturated calomel, ensuring the stability and accuracy of the potential and improving the sensor's measurement precision. The working electrode is made of platinum, glassy carbon, carbon nanotubes, common bio-carbon, poly(3,4-ethylenedioxythiophene), or polyethylene nitride. These materials have excellent conductivity and biocompatibility, effectively enhancing the sensor's response speed and sensitivity.

[0023] Optionally, the working electrode surface is provided with a biological enzyme membrane.

[0024] By employing the above technical solution, the bio-enzyme membrane significantly improves the detection sensitivity and selectivity of the working electrode for target substances. Specifically, the bio-enzyme membrane can effectively catalyze specific biochemical reactions, thereby enhancing signal response and ensuring accurate identification of target substances in complex samples. Furthermore, the bio-enzyme membrane exhibits good stability and a long service life, maintaining high activity even after multiple uses, further enhancing the overall performance and reliability of the sensor.

[0025] Optionally, the temperature of the vacuum sealing cavity is 2℃-8℃.

[0026] By adopting the above technical solution, the stability of the biosensor in low-temperature environments (2℃-8℃) is significantly improved, effectively reducing measurement errors caused by temperature fluctuations and extending the working life of the sensor.

[0027] In summary, this application includes at least one of the following beneficial technical effects:

[0028] 1. By utilizing a vacuum and low-temperature environment, moisture and oxygen are effectively isolated, resulting in strong airtightness, maintaining long-term sensor stability and measurement accuracy, and extending the sensor's lifespan. Furthermore, due to the effective isolation from external environmental influences, low-temperature vacuum packaging is particularly suitable for sensors requiring high precision and long-term stability, making the sensors more durable.

[0029] 2. The use of a nanoporous getter layer (such as a low-temperature activated metal oxide layer) further enhances the airtightness of the encapsulation cavity, extends the lifespan of the biosensor, and makes it more suitable for long-term storage or international transportation.

[0030] 3. The intermetallic compound layer (such as Cu3Sn or Cu6Sn5 layer) formed by Cu-Sn solid-state diffusion welding technology improves the mechanical strength and reliability of the packaging structure, ensuring the safety and stability of the sensor in practical applications. Attached Figure Description

[0031] Figure 1 This is a cross-sectional view of the overall structure of an embodiment of this application.

[0032] Figure 2 This is a top view of the polymer film (without a metal casing) as shown in the embodiments of this application.

[0033] Explanation of reference numerals in the attached figures:

[0034] 1. Flexible substrate; 11. Working electrode; 12. Reference electrode; 13. Counter electrode; 14. Working electrode contact; 15. Bioenzyme membrane; 2. Polymer membrane; 21. Vacuum encapsulation cavity; 3. Getter layer; 4. Metal shell; 5. Intermetallic compound layer. Detailed Implementation

[0035] The following will be combined with the appendix Figure 1-2 The technical solutions in the embodiments of this utility model are clearly and completely described herein. The described embodiments are only possible technical implementations of this utility model and not all possible implementations. Those skilled in the art can obtain other embodiments in conjunction with the embodiments of this utility model without creative effort, and these embodiments are also within the protection scope of this utility model.

[0036] The low-temperature vacuum packaging structure of the biosensor provided in this application embodiment is referenced. Figure 1 and Figure 2The system includes a flexible substrate 1, a polymer film 2, a getter layer 3, and a metal shell 4. The polymer film 2 is disposed on the surface of the flexible substrate 1, the getter layer 3 is disposed on the side of the polymer film 2 facing the flexible substrate 1, forming a vacuum sealing cavity 21 between the polymer film 2 and the surface of the flexible substrate 1. The metal shell 4 is disposed on the side of the polymer film 2 away from the flexible substrate 1 and is welded to the polymer film 2, achieving efficient and reliable vacuum sealing at lower temperatures.

[0037] Reference Figure 2 One end of the flexible substrate 1 is connected to a working electrode 11. The surface of the flexible substrate 1 is provided with a reference electrode 12, a counter electrode 13 and a working electrode contact 14. The reference electrode 12 and the counter electrode 13 are exposed outside the vacuum encapsulation cavity 21. The working electrode 11 and the counter electrode 13 form a polarization circuit. The working electrode contact 14 is electrically connected to the working electrode 11.

[0038] The working electrode 11, serving as the detection end, is primarily responsible for implantation into the human body for detection. Therefore, the surface of the working electrode 11 is coated with a biological enzyme membrane 15, which utilizes a chemical reaction to achieve detection. The biological enzyme membrane 15 can employ glucose oxidase, lactate dehydrogenase, or other specific biological enzymes. These enzymes can specifically recognize target substances and generate electrical signals, thereby enabling the detection of specific biological indicators. Simultaneously, the polymer membrane 2 covers most of the surface of the flexible substrate 1, exposing only necessary conductive areas, such as the reference electrode 12, the counter electrode 13, and the working electrode contact 14. This protects the surface area of ​​the flexible substrate 1 and extends its service life.

[0039] Specifically, the flexible substrate 1 can be made of various materials, such as polyethylene terephthalate (PET) or polyimide (PI). Both materials have good flexibility and temperature resistance, making them suitable for the encapsulation requirements of biosensors. Meanwhile, the polymer film 2 can be made of polyimide film, which has excellent thermal and chemical stability, making it suitable for low-temperature vacuum encapsulation.

[0040] Reference Figure 1 and Figure 2 Therefore, the flexible substrate 1 and the polymer film 2 can be connected by adhesion. Specifically, the sides of the flexible substrate 1 and the polymer film 2 can be bonded together using thermosetting epoxy adhesive. When bonding most of the sides, a vacuum is drawn between the flexible substrate 1 and the polymer film 2 to form a vacuum sealing cavity 21. Finally, the open sides are bonded to achieve vacuum sealing. Preferably, the pressure of the vacuum sealing cavity 21 is below 50 mTorr.

[0041] The getter layer 3 is a low-temperature activated metal oxide layer, such as a zirconium oxide layer or a titanium oxide layer, which are nanoporous layers. These materials can continuously adsorb gases, maintain a low-temperature vacuum environment, and reduce the impact of moisture and oxygen on the sensor. During processing, the metal oxide is heated to activate it, and surface moisture and impurities are removed under vacuum or nitrogen conditions to restore its maximum adsorption capacity. Then, the activated metal oxide is uniformly coated on the inner side of the polymer film 2, and finally, the polymer film 2 and the flexible substrate 1 are bonded together.

[0042] Optionally, the temperature of the vacuum sealing cavity 21 is 2℃-8℃, preferably 5℃, which can significantly improve the stability of the sensor, effectively reduce the measurement error caused by temperature fluctuations, and extend the working life of the sensor.

[0043] Specifically, the metal casing 4 can be made of copper or a copper alloy, etc. The metal casing 4 is welded to the polymer film 2, and the welding layer between the metal casing 4 and the polymer film 2 is an intermetallic compound layer 5. Preferably, the intermetallic compound layer 5 is a Cu3Sn layer or a Cu6Sn5 layer. The manufacturing process of the Cu3Sn layer or Cu6Sn5 layer is as follows: using evaporation deposition or sputtering deposition technology, a tin layer is uniformly deposited onto the outer surface of the polymer film 2, then heated and subjected to appropriate pressure. Through Cu-Sn welding technology, the tin layer and the metal casing 4 undergo a diffusion reaction to form a Cu3Sn or Cu6Sn5 intermetallic compound.

[0044] In addition, the working electrode 11 can be made of platinum, glassy carbon, carbon nanotubes, common bio-carbon, poly(3,4-ethylenedioxythiophene), or polyethylene nitride. These materials have excellent conductivity and biocompatibility, which can effectively enhance the sensor's response speed and sensitivity. The reference electrode 12 is made of silver chloride or saturated calomel electrode, which ensures the stability and accuracy of the potential and improves the sensor's measurement accuracy.

[0045] The implementation principle of this embodiment is as follows: by employing a combined design of a flexible substrate 1, a polymer film 2, a getter layer 3, and a metal shell 4, efficient and reliable low-temperature vacuum encapsulation is achieved at lower temperatures. The introduction of the flexible substrate 1 makes the entire encapsulation structure more flexible and adaptable; the effective cooperation between the polymer film 2 and the getter layer 3 ensures that the vacuum state within the encapsulation cavity is maintained for a long time; and the use of the metal shell 4 provides additional physical protection, enhancing the overall reliability and stability of the encapsulation structure. This design effectively prevents interference from the external environment on the biosensor, improving the long-term operating performance and reliability of the biosensor.

[0046] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A low-temperature vacuum packaging structure for a biosensor, characterized in that: The system includes a flexible substrate (1), a polymer film (2) on the surface of the flexible substrate (1), an air-absorbing layer (3) on the side of the polymer film (2) facing the flexible substrate (1), a vacuum encapsulation cavity (21) is formed between the polymer film (2) and the surface of the flexible substrate (1), and a metal shell (4) on the side of the polymer film (2) away from the flexible substrate (1), and the metal shell (4) is welded to the polymer film (2).

2. The low-temperature vacuum packaging structure of the biosensor according to claim 1, characterized in that: The welding layer between the metal shell (4) and the polymer film (2) is an intermetallic compound layer (5).

3. The low-temperature vacuum packaging structure of the biosensor according to claim 2, characterized in that: The intermetallic compound layer (5) is a Cu3Sn layer or a Cu6Sn5 layer.

4. The low-temperature vacuum packaging structure of the biosensor according to claim 1, characterized in that: The polymer film (2) is a polyimide film.

5. The low-temperature vacuum packaging structure of the biosensor according to claim 1, characterized in that: The air-absorbing layer (3) is a low-temperature activated metal oxide layer.

6. The low-temperature vacuum packaging structure of the biosensor according to claim 5, characterized in that: The low-temperature activated metal oxide layer is a zirconium oxide layer or a titanium oxide layer.

7. The low-temperature vacuum packaging structure of the biosensor according to claim 1, characterized in that: One end of the flexible substrate (1) is connected to a working electrode (11). A reference electrode (12) and a counter electrode (13) are provided on the surface of the flexible substrate (1). The reference electrode (12) and the counter electrode (13) are exposed outside the vacuum encapsulation cavity (21). The working electrode (11) and the counter electrode (13) form a polarization circuit.

8. The low-temperature vacuum packaging structure of the biosensor according to claim 7, characterized in that: The flexible substrate (1) is made of polyethylene terephthalate or polyimide; the reference electrode (12) is made of silver chloride or saturated calomel electrode; and the working electrode (11) is made of platinum, glassy carbon, carbon nanotubes, ordinary biochar, poly(3,4-ethylenedioxythiophene), or polyethylene nitride.

9. The low-temperature vacuum packaging structure of the biosensor according to claim 7, characterized in that: The working electrode (11) has a bio-enzyme membrane (15) on its surface.

10. The low-temperature vacuum packaging structure of the biosensor according to claim 1, characterized in that: The temperature of the vacuum sealing cavity (21) is 2℃-8℃.

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