Microfluidic chip packaging structure and packaging method integrated with temperature sensor

Abstract

The application discloses a micro-fluidic chip packaging structure and a packaging method, which integrate a temperature sensor. The packaging structure comprises a substrate and a lead group. The substrate covers the lead group to form a flexible packaging structure. A cover plate of the micro-fluidic chip is sealed with a bottom plate of the micro-fluidic chip through the flexible packaging structure, and a sealed space for liquid drop flow is formed between the cover plate and the bottom plate. A temperature sensor is arranged in the flexible packaging structure at a position sealed with the cover plate and the bottom plate. The temperature sensor is connected with the outside through a sensor lead in the lead group. The temperature in the micro-fluidic chip can be sensed through the temperature sensor. The temperature sensor is designed in an integrated manner with the chip glue frame, so that the process flow of chip manufacturing is simplified, and the chip packaging integration degree is improved.

Description

Technical Field

[0001] This invention relates to the field of microfluidic chip packaging technology, and in particular to a microfluidic chip packaging structure and packaging method integrating a temperature sensor. Background Technology

[0002] The ultimate goal of Lab-on-a-Chip (LOC) research is to connect and coexist multiple units or modules with different functions at the microscale, enabling them to collaboratively complete a series of complex biochemical analyses, such as sample preparation, biological and chemical reactions, and separation and detection. Ultimately, all functional modules involved in fields such as biology and chemistry can be integrated onto a chip of just a few square centimeters, directly applicable to biochemical detection, rapid environmental detection, and more. However, existing LOCs that have been gradually deployed primarily rely on pressure-driven and thermal-driven methods for their core function—microfluidic actuation. These methods require external power, involve relatively large volumes of fluid, have numerous flow channel components, and consume high power. Furthermore, the actuation methods lack versatility across different devices, failing to fully utilize the effective function of the "droplet," the basic microfluidic manipulator. Therefore, developing an effective and easy-to-operate microfluidic platform-level droplet manipulation method is crucial for the future development of LOCs.

[0003] Electrowetting-on-dielectric (EWOD) involves adding a thin insulating film between a metal electrode and the electrolyte. When a certain voltage is applied between the liquid and the electrode, the surface tension of the liquid and solid undergoes a reversible change, manifested as a change in the contact angle θ of the droplet on the solid surface. When the contact angle θ changes symmetrically and uniformly, the droplet macroscopically exhibits a process of spreading from a spherical droplet into a liquid film. However, if the contact angle θ changes asymmetrically, a surface tension gradient appears at the contact lines on both sides of the droplet, leading to droplet migration and movement. This is the theoretical basis for droplet manipulation in on-chip lab applications.

[0004] As the principle suggests, by utilizing the electrowetting effect and manipulating the voltage of electrodes, tiny droplets can be controlled on a chip. Specific manipulations include migration, segmentation, mixing, and oscillation. Through the combination of these functions, various biological and chemical experimental procedures can be transferred to the chip, thus realizing a laboratory-on-a-chip (PAC) system. Biological and chemical experimental procedures are quite complex, each requiring numerous electrodes. Therefore, one of the key technologies for realizing a PAC chip is the formation of a large number of driving electrodes and the provision of driving signals to drive the droplets to operate as required.

[0005] By combining the principle of electrowetting with arrayed driving electrode plates, a digital microfluidic chip with a certain degree of droplet manipulation capability is formed. Functional droplets replace ordinary droplets, and specific reagent handling processes are mapped onto the digital microfluidic chip, resulting in a digital microfluidic chip with certain reagent processing capabilities. In some biological or chemical applications, the internal liquid temperature of the microfluidic chip needs precise control to ensure the normal progress of biochemical reactions, especially in the formation of molecular-level products, where both yield and output are affected by the reaction temperature.

[0006] Existing temperature control methods are relatively mature, but efficient and accurate temperature measurement methods are lacking. Common temperature measurement methods include temperature sensing feedback via a bottom temperature control plate (see [link to relevant documentation]). Figure 1 This fixed temperature measurement method avoids the need to replace sensors during chip replacement, saving on sensor and calibration costs. However, since the chip is mostly exposed to room temperature, the temperature control boundary conditions are unstable. There is a certain error and conduction delay between the temperature fed back by the temperature control board and the internal temperature of the chip, which poses a risk of reduced stability in the internal temperature control of the chip. Summary of the Invention

[0007] In view of the problems existing in the prior art, the purpose of this invention is to provide a microfluidic chip packaging structure and packaging method for integrating a temperature sensor, thereby overcoming at least to some extent one or more problems caused by the limitations and defects of the prior art.

[0008] To achieve the above objectives, the first aspect of the present invention provides a microfluidic chip packaging structure integrating a temperature sensor, comprising a substrate and a lead assembly. The substrate covers the lead assembly to form a flexible packaging structure. The cover plate of the microfluidic chip is sealed to the base plate of the microfluidic chip through the flexible packaging structure, forming a sealed space for droplet flow between the cover plate and the base plate. A temperature sensor is disposed within the flexible packaging structure at the packaging position of the cover plate and the base plate. The temperature sensor is connected to the outside through a sensor lead in the lead assembly, and the temperature inside the microfluidic chip can be sensed by the temperature sensor.

[0009] Furthermore, the flexible packaging structure includes a sealing end and a wiring end. The temperature sensor is disposed within the flexible packaging structure on one side of the sealing end, and the electrode leads in the lead group are disposed on the bottom surface of the flexible sealing structure on one side of the wiring end, so that the cover plate is sealed to the base plate through the flexible packaging structure and connected to the driving electrode of the microfluidic chip through the electrode leads.

[0010] Furthermore, a driving electrode and an extraction electrode for driving the droplet to move on the base plate are formed thereon. The driving electrode and the extraction electrode are electrically connected. The driving electrode is connected to an external power supply device through the extraction electrode. The electrode lead of the flexible packaging structure is electrically connected to the extraction electrode. The electrode lead is connected to the driving electrode through the extraction electrode.

[0011] Furthermore, the substrate is made of polyimide or polyester film, and the substrate includes copper foil wires to form the flexible encapsulation structure.

[0012] Furthermore, the thickness of the flexible packaging structure is 700 μm, and the thickness of the temperature sensor is 500 μm.

[0013] Furthermore, the horizontal distance between the temperature sensor and the edges of the cover plate and the bottom plate is greater than 5 mm.

[0014] Furthermore, the temperature sensor is positioned close to the droplet's active region, and the distance between the temperature sensor and the droplet's active region is at least greater than or equal to one electrode distance and less than or equal to N electrode distances.

[0015] Furthermore, the flexible packaging structure is made of hydrophobic material, and an electromagnetic shielding layer is also provided on the outer surface of the temperature sensor.

[0016] A second aspect of the present invention provides a microfluidic chip, including a cover plate, a base plate, and an encapsulation structure as described above. The cover plate is sealed to the base plate by the flexible encapsulation structure, and a space for droplet flow is formed between the cover plate and the base plate. A driving electrode for driving the droplet to move on the base plate is formed on the base plate.

[0017] A third aspect of the present invention provides a packaging method for a microfluidic chip, utilizing the above-described packaging structure, the packaging method comprising the following steps:

[0018] Pressure-sensitive adhesive is applied to the bottom and top surfaces of the sealed side of the flexible encapsulation structure;

[0019] The flexible packaging structure is placed on one side of the base plate of the microfluidic chip and pressure is applied to seal and fix the bottom surface of the flexible packaging structure to the base plate.

[0020] Place a rubber frame on the other side of the base plate and apply pressure to seal and fix the rubber frame to the other side of the base plate;

[0021] The cover plate of the microfluidic chip is placed on the top surface of the flexible packaging structure and the frame, and pressure is applied to seal and fix the top surface of the flexible packaging structure to the cover plate.

[0022] This invention simplifies the chip manufacturing process and improves chip packaging integration by integrating the temperature sensor with the chip housing. It provides an effective temperature measurement method for microfluidic chip applications while avoiding the design redundancy introduced by implanted temperature measurement methods. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figures 1-2 This is a schematic diagram of a temperature measurement structure for a microfluidic chip in the prior art;

[0025] Figures 3-4 This is a schematic diagram of the microfluidic chip packaging structure of an integrated temperature sensor according to an embodiment of the present invention; Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0027] like Figure 2 As shown, while embedding a temperature sensor inside a microfluidic chip to measure internal temperature changes can solve problems such as inaccurate temperature measurement and conduction delay caused by externally placed sensors, the method of embedding the temperature sensor involves drilling a hole in one side of the encapsulation frame after the microfluidic chip is encapsulated in a plastic frame and then embedding the temperature sensor into the chip. The process of embedding the sensor is complicated, and because the microfluidic chip is small, the method of encapsulating and then drilling a hole to embed the sensor requires high construction precision and is prone to damaging the microfluidic chip.

[0028] To solve the above problems, such as Figure 3-4As shown, the microfluidic chip packaging structure with integrated temperature sensor of the present invention includes a substrate 10 and a lead group. The substrate 10 covers the lead group to form a flexible packaging structure. The cover plate 11 of the microfluidic chip is sealed to the bottom plate 12 of the microfluidic chip through the flexible packaging structure, forming a sealed space for droplet flow between the cover plate 11 and the bottom plate 12. A temperature sensor 13 is disposed within the flexible packaging structure at the packaging position of the cover plate 11 and the bottom plate 12. The temperature sensor 13 is connected to the outside through a sensor lead 14 in the lead group, and can sense the temperature inside the microfluidic chip. In this embodiment, the flexible sealing structure is an FPC. By placing the temperature sensor in one end of the FPC and using the FPC as a frame to support and seal the microfluidic chip, the temperature sensor can be implanted into the microfluidic chip while sealing it. The temperature sensor implantation is performed simultaneously with chip packaging, simplifying the chip manufacturing process, reducing the difficulty of implanting the temperature sensor, and providing an effective temperature measurement method for microfluidic chip applications.

[0029] In one embodiment of the present invention, the flexible packaging structure includes a sealing end and a wiring end. The temperature sensor 13 is disposed within the flexible packaging structure on one side of the sealing end, and the electrode leads 15 in the lead group are disposed on the bottom surface of the flexible sealing structure on one side of the wiring end. This allows the cover plate 11 to be sealed to the base plate 12 through the flexible packaging structure and simultaneously connected to the driving electrode of the microfluidic chip through the electrode leads 15. This embodiment integrates electrode leads and sensor leads within the flexible packaging structure, facilitating the connection of the temperature sensor and driving electrode to external devices.

[0030] In one embodiment of the present invention, a driving electrode 121 and a lead-out electrode 122 for driving the droplet to move on the base plate 12 are formed on the base plate 12. The driving electrode 121 and the lead-out electrode 122 are electrically connected, and the driving electrode 122 is connected to an external power supply device through the lead-out electrode 121. The electrode lead 15 of the flexible packaging structure is electrically connected to the lead-out electrode 121, and the electrode lead 15 is connected to the driving electrode 121 through the lead-out electrode 121. In this embodiment, after the flexible packaging structure is packaged into the microfluidic chip, the electrode lead 15 provided at the bottom of the flexible packaging structure can be easily pressed onto the exposed lead-out electrode 121 outside the microfluidic chip. This allows for convenient simultaneous connection of the driving electrode inside the chip through a single packaging process, simplifying the process and reducing costs.

[0031] In one embodiment of the present invention, the substrate 10 is made of polyimide or polyester film, which serves as insulation and support, and the substrate 10 includes copper foil wires to form the flexible encapsulation structure.

[0032] In one embodiment of the present invention, the thickness of the flexible packaging structure is 700 μm, and the thickness of the temperature sensor 13 is 500 μm.

[0033] In one embodiment of the present invention, the horizontal distance between the temperature sensor 13 and the edges of the cover plate 11 and the base plate 12 is greater than 5mm, so that the temperature sensor is embedded in the chip at a certain depth, thereby reducing the interference of uneven temperature distribution.

[0034] In one embodiment of the present invention, the temperature sensor 13 is positioned close to the droplet activity region, and the distance between the temperature sensor and the droplet activity region is at least greater than or equal to one electrode distance and less than or equal to N electrode distances. This ensures that the temperature sensor can accurately measure the operating temperature of the droplet during chip operation, while preventing droplet flow from interfering with the measurement accuracy. Conversely, when the distance between the temperature sensor and the droplet activity region is less than one electrode distance, the measurement accuracy will be affected by droplet flow.

[0035] In one embodiment of the present invention, the flexible packaging structure is made of a hydrophobic material to prevent droplets from accumulating or adhering to the outer surface of the sealed end of the flexible packaging structure, thus affecting the temperature sensor's detection results. Preferably, the hydrophobic material used in the flexible packaging structure has a higher hydrophobicity than the material of the inner wall of the microfluidic chip's sealed space, making it less likely for droplets to accumulate or adhere to the outer surface of the sealed end of the flexible packaging structure. Furthermore, to improve the measurement accuracy of the temperature sensor, an electromagnetic shielding layer is provided on the outer surface of the temperature sensor 13 to prevent electromagnetic interference with the sensor's detection results. A certain distance is maintained between the temperature sensor 13 and the driving electrode and heating electrode disposed within the microfluidic chip; that is, no driving electrode or heating electrode is disposed above or below the temperature sensor 13 to prevent the electric field generated by the driving electrode from affecting the temperature sensor and to avoid the influence of the heating electrode on the detection results.

[0036] like Figure 3 As shown, one embodiment of the present invention also provides a microfluidic chip, including a cover plate 11, a base plate 12, and the aforementioned packaging structure. The cover plate 11 is sealed to the base plate 12 through the flexible packaging structure, forming a space for droplet flow between the cover plate 11 and the base plate 12. A driving electrode 121 for driving the droplet to move on the base plate 12 is formed on the base plate 12. An injection port for injecting droplets is provided on the cover plate 11.

[0037] An embodiment of the present invention also provides a packaging method for a microfluidic chip. Utilizing the above-described packaging structure, the packaging method includes the following steps:

[0038] Pressure-sensitive adhesive is applied to the bottom and top surfaces of the sealed side of the flexible encapsulation structure;

[0039] The flexible packaging structure is placed on one side of the base plate of the microfluidic chip and pressure is applied to seal and fix the bottom surface of the flexible packaging structure to the base plate.

[0040] Place a rubber frame on the other side of the base plate and apply pressure to seal and fix the rubber frame to the other side of the base plate;

[0041] The cover plate of the microfluidic chip is placed on the top surface of the flexible packaging structure and the frame, and pressure is applied to seal and fix the top surface of the flexible packaging structure to the cover plate.

[0042] In summary, this invention simplifies the chip manufacturing process and improves chip packaging integration by integrating the temperature sensor with the chip housing. This invention provides an effective temperature measurement method for microfluidic chip applications while avoiding the design redundancy introduced by implanted temperature measurement methods in the chip structure.

[0043] It should be understood that this disclosure is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this disclosure is limited only by the appended claims.

Claims

1. A microfluidic chip packaging structure integrating a temperature sensor, characterized in that, The device includes a substrate and a lead assembly. The substrate is a polyimide or polyester film, and the substrate contains copper foil conductors. The substrate covers the lead assembly to form a flexible encapsulation structure. The flexible encapsulation structure is a flexible printed circuit board (FPC) and forms a frame for supporting and sealing the microfluidic chip. The flexible encapsulation structure includes a sealing end arranged circumferentially along the microfluidic chip and a terminal connected to the sealing end. The cover plate of the microfluidic chip is sealed to the base plate of the microfluidic chip through the sealing end, and a sealed space for droplet flow is formed between the cover plate and the base plate. A temperature sensor is disposed within the sealed end at the encapsulation location of the cover plate and the base plate. The temperature sensor is connected to the outside via sensor leads in the lead assembly, and can sense the temperature inside the microfluidic chip. A driving electrode for driving the droplet to move on the base plate and an output electrode electrically connected to the driving electrode are formed on the base plate. The electrode leads in the lead assembly are disposed on the side of the terminal facing the base plate and are electrically connected to the output electrode, so that the driving electrode and the temperature sensor can be electrically connected to the external device while the microfluidic chip is encapsulated using the flexible packaging structure.

2. The microfluidic chip packaging structure as described in claim 1, characterized in that, The thickness of the flexible packaging structure is 700 μm, and the thickness of the temperature sensor is 500 μm.

3. The microfluidic chip packaging structure as described in claim 1, characterized in that, The temperature sensor is located at a horizontal distance greater than 5 mm from the edges of the cover plate and the base plate.

4. The microfluidic chip packaging structure as described in claim 1, characterized in that, The temperature sensor is positioned close to the droplet's active region, and the distance between the temperature sensor and the droplet's active region is at least greater than or equal to one electrode distance and less than or equal to N electrode distances.

5. The microfluidic chip packaging structure as described in claim 1, characterized in that, The flexible packaging structure is made of hydrophobic material, and the outer surface of the temperature sensor is also provided with an electromagnetic shielding layer.

6. A microfluidic chip, characterized in that, The device includes a cover plate, a base plate, and an encapsulation structure as described in any one of claims 1-5, wherein the cover plate is sealed to the base plate by the flexible encapsulation structure and forms a space for droplet flow between the cover plate and the base plate; and a driving electrode for driving the droplet to move on the base plate is formed thereon on the base plate.

7. A method for packaging a microfluidic chip, characterized in that, Utilizing the packaging structure as described in any one of claims 1-5, the packaging method includes the following steps: Pressure-sensitive adhesive is applied to the bottom and top surfaces of the sealed side of the flexible encapsulation structure; The flexible packaging structure is placed on one side of the base plate of the microfluidic chip and pressure is applied to seal and fix the bottom surface of the flexible packaging structure to the base plate. Place a rubber frame on the other side of the base plate and apply pressure to seal and fix the rubber frame to the other side of the base plate; The cover plate of the microfluidic chip is placed on the top surface of the flexible packaging structure and the frame, and pressure is applied to seal and fix the top surface of the flexible packaging structure to the cover plate.

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