Integrated manufacturing method of high-precision micro-fluidic chip

Abstract

The invention discloses an integrated manufacturing method of a high-precision micro-fluidic chip, and relates to the technical field of chip manufacturing. The method comprises the following steps: providing a precision mold, wherein a cavity of the mold defines a micro-channel network and a functional chamber of the micro-fluidic chip; an independent and removable sacrificial mandrel is accurately assembled and fixed at a predetermined position of the mold before mold closing, and the sacrificial mandrel is used for directly defining the complete three-dimensional geometry of the fluid interface in the forming process. The sacrificial core shaft and the chip main body are integrally formed, so that the defects of interface collapse of a traditional bonding process and burrs of secondary machining are fundamentally eliminated, and high-precision and leakage-free manufacturing of a fluid interface is realized. According to the method, the reliability and the consistency of the chip are greatly improved, synchronous manufacturing of a complex three-dimensional flow channel and a high-quality interface is realized through an optional'dual sacrifice technology ', and the function integration capability of the micro-fluidic chip is remarkably enhanced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of chip manufacturing, in particular to an integrated manufacturing method of high-precision microfluidic chip. BACKGROUND

[0002] Microfluidic chip technology is widely used in biomedical analysis, drug screening, environmental monitoring and other frontier fields because it can precisely manipulate micro-volume fluid in micron-scale channels. With the deepening of application scenarios, higher requirements are put forward for the functional complexity, analysis accuracy and reliability of the chip, which makes it a core technology trend to integrate multiple functional units (such as mixers, reaction chambers, detection units, etc.) in a single chip at high density, thereby bringing severe challenges to the precision and consistency of the integrated manufacturing process.

[0003] At present, the mainstream microfluidic chip manufacturing methods such as soft lithography and substrate bonding process have inherent defects in realizing high-precision integration. For the widely used polydimethylsiloxane (PDMS) and glass bonding technology, the interface collapse and non-uniform sealing are easily caused by material elastic deformation and uneven bonding pressure in the chip fluid interface (i.e. inlet / outlet) area, which introduces fluid dynamics disturbance, bubble nucleation and leakage risk; and for the injection molding technology of thermoplastic polymers, the fluid interface usually relies on subsequent mechanical processing (such as drilling) to form, which inevitably produces burrs and debris during the secondary processing, which also destroys the flow field and introduces pollution. The root cause of these defects is that the existing technologies have not achieved integrated, bonding-free and secondary processing-free molding manufacturing of fluid interfaces and internal microfluid channel networks, which seriously restricts the performance and yield of high-precision microfluidic chips.

[0004] Therefore, an integrated manufacturing method of high-precision microfluidic chip is proposed. SUMMARY

[0005] The purpose of the present application is to solve the problems mentioned in the background art, and the present application provides an integrated manufacturing method of high-precision microfluidic chip.

[0006] In order to achieve the above purpose, the present application specifically adopts the following technical scheme: an integrated manufacturing method of high-precision microfluidic chip, comprising the following steps: providing a precision mold, the cavity of the mold defining the microfluid channel network and functional chamber of the microfluidic chip; an independent and removable sacrificial mandrel is precisely assembled and fixed at a predetermined position of the mold before clamping, the sacrificial mandrel being used to directly define the complete three-dimensional geometry of the fluid interface during molding; After the sacrificial mandrel is in place, a molten polymer material is injected into the closed mold, and a one-piece chip substrate is formed that completely encapsulates the sacrificial mandrel within the interior thereof after a filling, pressure-holding, and cooling solidification process; The sacrificial mandrel is completely removed from the one-piece chip substrate by physical or chemical means, thereby directly obtaining a fluidic interface that is in seamless communication with the microfluidic network and functional chamber and has an inner wall topography that is accurately replicated from the outer surface of the sacrificial mandrel. The inner wall topography of the fluidic interface throughout its depth range is formed without relying on any subsequent mechanical processing or wafer bonding process.

[0007] Further, the working section of the sacrificial mandrel is configured to have functional micro-geometric features, such that the inner wall of the formed fluidic interface forms corresponding mechanical interlocking structures.

[0008] Further, the mechanical interlocking structures are inverted tapered surfaces, microthreads, or annular convex ribs.

[0009] Further, the sacrificial mandrel is made of a rigid metallic material, and the removal step is achieved by mechanical pulling by applying a pulling force along the axial direction thereof.

[0010] Further, the sacrificial mandrel is made of a soluble material or a low-melting-point material, including a water-soluble polymer material or a low-melting-point metal, and the removal step is achieved by solvent dissolution or heating melting.

[0011] Further, the polymer material is an engineering plastic selected from cyclic olefin copolymer (COC), polycarbonate (PC), or polymethyl methacrylate (PMMA).

[0012] Further, the forming of the microfluidic network and functional chamber further includes: in the mold preparation step, a sacrificial material inner core defining the three-dimensional structure of the microfluidic network is pre-provided in the cavity; in the one-piece injection molding step, the polymer material encapsulates the sacrificial material inner core; and before or after the sacrificial mandrel removal step, the sacrificial material inner core is removed by etching or dissolving.

[0013] Further, the inner wall of the fluidic interface is further subjected to surface treatment, and the surface treatment includes plasma activation, chemical vapor deposition, or graft polymerization to change the surface chemical properties thereof.

[0014] The beneficial effects of the present application are as follows: 1. The present application is formed by sacrificial mandrel and chip body one-time injection molding, so that the inner wall morphology of the fluid interface is accurately copied from the surface of the mandrel, avoiding the "interface collapse" and non-uniform sealing caused by elastic deformation in the traditional PDMS bonding process, and the "burr and debris" generated by traditional drilling after injection molding. The method realizes seamless and bonding-free connection of the fluid interface and the internal microchannel, completely eliminates the leakage risk from the root, and significantly improves the yield, performance consistency and long-term reliability of the chip.

[0015] 2. The present application can simultaneously manufacture a chip with complex three-dimensional internal flow channel and high-quality integrated interface with mechanical interlocking structure by introducing "double sacrifice technology" and mandrel that can construct functional geometric features. This breaks through the limitation of traditional manufacturing methods on the complexity of chip structure, and provides an advanced manufacturing process basis for developing higher performance and more functional integrated microfluidic systems. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 is a schematic diagram of the method of the present application; DETAILED DESCRIPTION

[0017] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all. The components of the embodiments of the present application described and shown in the drawings herein can be arranged and designed in various different configurations.

[0018] Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed application, but only represents selected embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative labor are within the scope of protection of the present application.

[0019] It should be noted that: similar numbers and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings. In addition, the terms "first", "second" and the like are only used to distinguish description, and cannot be understood as indicating or implying relative importance.

[0020] The electrical components appearing in this paper are all connected with the main controller and 220V mains of the outside world, and the main controller can be a conventional known device such as a computer.

[0021] In the description of the embodiments of the present application, it should be noted that the terms "inner", "outer", "upper", and the like indicate the positional or location relationship shown in the drawings, or the positional or location relationship when the product of the present application is used, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0022] As shown in Figure 1 An integrated manufacturing method of a high-precision microfluidic chip, comprising the following steps: A precision mold is provided, and the cavity of the mold defines the microfluidic network and functional chamber of the microfluidic chip; An independent and removable sacrificial mandrel is precisely assembled and fixed at a predetermined position of the mold before the mold is closed, and the sacrificial mandrel is used to directly define the complete three-dimensional geometry of the fluid interface during the molding process; After the sacrificial mandrel is in place, molten polymer material is injected into the closed mold, and after the filling, pressure maintaining and cooling and solidification processes, a monolithic chip substrate is formed which completely covers the sacrificial mandrel inside; The sacrificial mandrel is completely removed from the monolithic chip substrate by physical or chemical means, thereby directly obtaining a fluid interface that is in seamless communication with the microfluidic network and functional chamber, and has an inner wall topography accurately copied from the outer surface of the sacrificial mandrel; Wherein, the inner wall topography of the fluid interface throughout its depth range is not dependent on any subsequent mechanical processing or substrate bonding process.

[0023] The integration of the fluid interface and the chip body is achieved by precision injection molding. The precision mold is usually made of mold steel through micro-machining technology to ensure the dimensional accuracy of the cavity. The precise positioning and fixing of the sacrificial mandrel before the mold is closed is the key to ensuring the accurate alignment of the fluid interface and the internal microfluidic network, thereby eliminating the cumulative error in the traditional bonding process. The monolithic chip substrate formed finally means that the chip body and the fluid interface are a single continuous polymer phase, without a physical interface, which completely eliminates the risk of interface leakage.

[0024] The working section of the sacrificial mandrel is configured to have functional micro-geometric features, so that the inner wall of the molded fluid interface forms a corresponding mechanical interlocking structure.

[0025] By designing specific functional micro-geometric features in the working section of the mandrel, a corresponding mechanical interlocking structure can be replicated on the inner wall of the formed fluid interface. The main function of this structure is to significantly improve the interface's pull-out resistance and connection seal reliability by increasing static friction and clamping force when an external conduit is inserted, thereby enhancing the mechanical robustness of the microfluidic system in dynamic fluid environments.

[0026] The mechanical interlocking structure is an inverted conical surface, micro-thread, or annular rib.

[0027] The inverted conical surface achieves fastening through its self-locking effect; the micro-thread provides reliable mechanical locking and sealing through the helical meshing principle; and the annular ribs utilize the elastic deformation of polymer materials to form multi-point sealing and high resistance on the outer wall of the conduit.

[0028] The sacrificial mandrel is made of a rigid metal material, and its removal is achieved by mechanically pulling it out by applying a traction force along its axis.

[0029] Utilizing rigid metal materials such as high-strength stainless steel ensures extremely high dimensional stability and shape accuracy of the mandrel during injection molding, and replicates a high-gloss inner wall surface. Its removal is achieved through axial mechanical pulling, a simple process path easily automated, suitable for large-scale, high-efficiency production.

[0030] The sacrificial mandrel is made of a soluble or low-melting-point material, including water-soluble polymers or low-melting-point metals, and its removal is achieved by solvent dissolution or heating and melting.

[0031] Water-soluble polymers (such as PVA) or low-melting-point metals (such as Wood's alloy) are used as core materials, and their removal is accomplished by solvent dissolution or heating and melting, respectively. This method avoids mechanical stress and does not damage the chip body, making it particularly suitable for forming fluid interfaces with complex geometries or negative angle structures.

[0032] The polymer material is an engineering plastic selected from cyclic olefin copolymers (COC), polycarbonate (PC), or polymethyl methacrylate (PMMA).

[0033] The selected cyclic olefin copolymers (COC), polycarbonate (PC), and polymethyl methacrylate (PMMA) are all engineering plastics with high dimensional stability, excellent processing flowability, and good overall mechanical properties. Among them, COC is particularly suitable for high-end microfluidic applications with stringent requirements for precision and biocompatibility due to its extremely low water absorption and biocompatibility.

[0034] The molding of the microfluidic network and functional chambers further includes: in the mold preparation step, pre-setting a sacrificial material core that defines the three-dimensional structure of the microfluidic network in the cavity; in the integral injection molding step, covering the sacrificial material core with polymer material; and removing the sacrificial material core by etching or dissolution before or after the sacrificial mandrel removal step.

[0035] This is a "double-sacrifice technique," which combines a sacrificial mandrel used to form the macroscopic fluid interface with a sacrificial material core used to define the complex internal three-dimensional microchannel network. After injection molding, by sequentially removing the two sacrificial materials, a chip structure with a high-quality integrated interface and complex internal channels can be obtained simultaneously. This method achieves the highest precision integrated manufacturing of the chip's internal and external structures, greatly expanding the chip's functional integration potential.

[0036] It also includes surface treatment of the inner wall of the fluid interface, including plasma activation, chemical vapor deposition, or graft polymerization, to change its surface chemical properties.

[0037] By treating the inner wall of the formed fluid interface with plasma activation, chemical vapor deposition, or graft polymerization, its surface energy, hydrophilicity / hydrophobicity, or the introduction of specific functional groups can be directionally controlled. This step aims to optimize the chip's interface performance to meet the surface chemistry requirements of specific applications such as cell culture and protein separation, and is an important post-processing technology for improving chip functionality and application range.

[0038] In summary, this invention utilizes a sacrificial mandrel and chip body in a single injection molding process, precisely replicating the inner wall morphology of the fluid interface from the mandrel surface. This avoids the "interface collapse" and non-uniform sealing caused by elastic deformation in traditional PDMS bonding processes, as well as the "burrs and debris" generated by drilling after injection molding. This method achieves a seamless, bond-free connection between the fluid interface and the internal microchannels, eliminating leakage risks at the source and significantly improving chip yield, performance consistency, and long-term reliability. By introducing "double sacrifice technology" and a mandrel capable of constructing functional geometries, this invention can simultaneously manufacture high-quality integrated interfaces with complex three-dimensional internal channels and mechanical interlocking structures. This overcomes the limitations of traditional manufacturing methods on chip structural complexity, providing an advanced manufacturing process foundation for developing higher-performance, more functional integrated microfluidic systems.

[0039] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention. The scope of protection claimed by the appended claims and their equivalents is defined.

Claims

1. An integrated manufacturing method for a high-precision microfluidic chip, characterized in that, Includes the following steps: A precision mold is provided, the cavity of which defines the microchannel network and functional chambers of the microfluidic chip; A separate, removable sacrificial mandrel is precisely assembled and fixed in a predetermined position in the mold before mold closing. The sacrificial mandrel is used to directly define the complete three-dimensional geometry of the fluid interface during the molding process. After the sacrificial mandrel is in place, molten polymer material is injected into the closed mold. After the molding, pressure holding and cooling solidification process, an integral chip substrate is formed that completely encapsulates the sacrificial mandrel inside. The sacrificial mandrel is completely removed from the monolithic chip substrate by physical or chemical means, thereby directly obtaining a fluid interface that is seamlessly connected to the microchannel network and functional chambers and has an inner wall morphology that is precisely replicated from the outer surface of the sacrificial mandrel. The fluid interface's inner wall morphology is formed independently of any subsequent machining or substrate bonding process throughout its entire depth range.

2. The integrated manufacturing method of a high-precision microfluidic chip according to claim 1, characterized in that, The working section of the sacrificial mandrel is configured with functional micro-geometric features, such that the inner wall of the formed fluid interface forms a corresponding mechanical interlocking structure.

3. The integrated manufacturing method for a high-precision microfluidic chip according to claim 2, characterized in that, The mechanical interlocking structure is an inverted conical surface, a micro-thread, or an annular rib.

4. The integrated manufacturing method of a high-precision microfluidic chip according to claim 1, characterized in that, The sacrificial mandrel is made of a rigid metal material, and its removal is achieved by mechanically pulling it out by applying a traction force along its axial direction.

5. The integrated manufacturing method of a high-precision microfluidic chip according to claim 1, characterized in that, The sacrificial mandrel is made of a soluble or low-melting-point material, including water-soluble polymers or low-melting-point metals, and its removal is achieved by solvent dissolution or heating and melting.

6. The integrated manufacturing method of a high-precision microfluidic chip according to claim 1, characterized in that, The polymer material is an engineering plastic selected from cyclic olefin copolymers (COC), polycarbonate (PC), or polymethyl methacrylate (PMMA).

7. The integrated manufacturing method of a high-precision microfluidic chip according to claim 1, characterized in that, The forming of the microchannel network and functional chambers further includes: in the mold preparation step, a sacrificial material core defining the three-dimensional structure of the microchannel network is pre-set in the cavity; in the integral injection molding step, the sacrificial material core is covered with polymer material; and before or after the sacrificial mandrel removal step, the sacrificial material core is removed by etching or dissolution.

8. The integrated manufacturing method of a high-precision microfluidic chip according to claim 1, characterized in that, It also includes surface treatment of the inner wall of the fluid interface, the surface treatment including plasma activation, chemical vapor deposition or graft polymerization, to change its surface chemical properties.

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