Microstructure device manufacturing system and microstructure device manufacturing method

Abstract

To provide a microstructure device manufacturing system and a microstructure device manufacturing method capable of manufacturing a microstructure device quickly and precisely.SOLUTION: A microstructure device manufacturing system is configured in that: a microchannel design unit creates three-dimensional design data that configures a predetermined microchannel including a channel having an inclined side surface that widens from a bottom surface toward a top surface; a resin mold manufacturing unit uses photolithography to manufacture resin molds made of photocurable resin with the microchannel based on the created three-dimensional design data as convex portions; a structure molding unit places the resin mold inside an injection molding die of an injection molding machine, and injects molten resin to mold a microchannel structure in which the microchannel of the resin mold are transferred as recesses, and then removes the resin mold from the top surface of the microchannels of the microchannel structure to remove the microchannel structure; and a component assembling unit adds predetermined processing to the removed microchannel structure so as to incorporate predetermined components therein.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a microstructure device manufacturing system and a microstructure device manufacturing method. [Background technology]

[0002] Numerous systems and methods have been proposed for manufacturing microstructure devices having microstructures and microchannels, such as microfluidic chips (also called microchannel chips or fluidic devices) and IoT devices, or resin molded products for such microstructure devices. For example, Japanese Patent Application Laid-Open Publication No. 2016-028876 (Patent Document 1) discloses a method for manufacturing a mold for mass-producing resin molded products. This manufacturing method includes a first step, a second step, a third step, a fourth step, a fifth step, and a sixth step. In the first step, three-dimensional CAD data for a resin mold is created prior to manufacturing a mold for mass-producing resin molded products. In the second step, a resin mold is obtained by printing a photocurable resin having a deflection temperature under load of 45°C or higher using a 3D printer based on the three-dimensional CAD data for the resin mold. In the third step, the resin mold is used to mold resin raw materials for mass-producing resin molded products. In the fifth step, the molded product is inspected. The sixth step is to incorporate the results of the investigation into the manufacturing of molds for mass production of resin molded products, thereby ensuring that genuine parts molded using the molds can demonstrate the required performance.

[0003] Furthermore, Japanese Patent Laid-Open Publication No. 2017-104901 (Patent Document 2) discloses a method for producing a press-molded body by placing a workpiece between an upper mold attached to a vertically moving slide of a press machine and a lower mold fixed to a bolster, and then pressing the upper mold against the lower mold to press-mold the workpiece. Both the upper and lower molds are resin molds three-dimensionally shaped using a 3D printer. The workpiece is a metal plate with a thickness ranging from 0.1 mm to 6.0 mm. The thickness of each of the upper and lower molds at their deepest portions is at least 5 mm. This allows for the use of a resin mold three-dimensionally shaped using a 3D printer to easily and inexpensively produce multiple metal molded bodies of the same shape and size that are free of cracks, warping, scratches, and mold marks, without damaging the structure of the resin mold.

[0004] Furthermore, Japanese Patent Laid-Open Publication No. 2014-073643 (Patent Document 3) discloses a resin injection molding method comprising a master plate creation step and a pattern transfer step. In the master plate creation step, a substrate is coated with resist, and a master plate is created by photolithography or EB lithography. In the pattern transfer step, the master plate created in the master plate creation step is used as a mold, and liquid resin is injected into this mold, hardened, and released to obtain an injection-molded product with a transferred pattern. This is said to enable nano-level fine pattern transfer in a short time without going through complicated processes.

[0005] Furthermore, Japanese Patent Laid-Open Publication No. 2014-168777 (Patent Document 4) discloses a method for forming one or more particles. This method includes a first step, a second step, and a third step. The first step involves providing a patterned template and a substrate, the patterned template having a surface with a plurality of recessed regions formed therein. The second step involves disposing a volume of liquid material on the surface of the patterned template and on at least one of the recessed regions. The third step involves forming one or more particles by one of contacting the surface of the patterned template with the substrate and processing the liquid material, and processing the liquid material. This provides a method for fabricating isolated microstructures and isolated nanostructures using soft lithography or imprint lithography.

[0006] Furthermore, Japanese Patent Laid-Open Publication No. 2015-130497 (Patent Document 5) discloses a method for manufacturing a device using soft lithography, which method includes a first step, a second step, a third step, a fourth step, a fifth step, and a sixth step for generating nanoscale features. The first step generates a pattern on a substrate, the pattern including a molecular film including multiple microscale features and one nanoscale feature, and multiple microchannels generated in proximity to the molecular film, such that one microscale feature is in proximity to one nanoscale feature. The second step casts a moldable polymer composition onto the substrate. The third step partially cures the moldable polymer composition. The fourth step involves removing the partially cured moldable polymer composition from the substrate and forming a mold replicating the pattern to include a molecular membrane containing multiple microscale features and one nanoscale feature, as well as a reservoir positioned adjacent to the molecular membrane, allowing fluid to flow from one microscale feature to at least one nanoscale feature in the molecular membrane. The fifth step involves opening one or more access windows over one or more portions of the microchannels. The sixth step involves positioning one portion of the replicated pattern of the mold adjacent to a surface in an apparatus, drawing fluid through the molecular membrane from one reservoir through one access window into one of the multiple microchannels, and withdrawing the fluid out of the molecular membrane into another one of the multiple microchannels through one other access window and into at least one other reservoir. This provides a method for producing molecular membranes using soft lithography.

[0007] Furthermore, Japanese Patent Laid-Open Publication No. 2015-066778 (Patent Document 6) discloses a method for producing a molded article. In this production method, a semi-cured film laminate is formed by semi-curing a curable resin composition on a transparent substrate to form a semi-cured resin layer having a thickness of 10 μm to 1 mm and an elongation of 5% or more at room temperature. The semi-cured film laminate is then placed in an injection mold so that the semi-cured resin layer side is in close contact with the mold. Next, an injection molding resin is injected into the mold from the transparent substrate side to mold the injection molding resin, and simultaneously the injection molding resin and the semi-cured film laminate are integrated. The semi-cured resin layer is then completely cured to form a laminate in which the hard coat layer, transparent substrate, and injection molding resin are integrated. This provides a method for producing an injection-molded article using a semi-cured film laminate that has extremely high surface hardness as a hard coat for a transparent substrate and excellent adhesion and conformability to resin molded articles with three-dimensional curved surfaces.

[0008] Furthermore, Patent Document 7 (2011 / 046169) discloses a method for fabricating a microstructure, including a first step and a second step. In the first step, a first mask pattern including light-transmitting portions with a relatively high light transmission rate and light-shielding portions with a relatively low light transmission rate is disposed along an unexposed photosensitive resin, and a second mask pattern including light-transmitting portions with a relatively high light transmission rate and light-shielding portions with a relatively low light transmission rate is disposed on the opposite side of the photosensitive resin with respect to the first mask pattern. In the second step, the photosensitive resin and the first mask pattern are rotated integrally about a central axis penetrating the photosensitive resin and the first mask pattern as a rotation center, and exposure light is irradiated on the opposite side of the second mask pattern from the photosensitive resin and the first mask pattern from a direction tilted with respect to the central axis, thereby exposing the photosensitive resin to the luminous flux of exposure light that has passed through the second mask pattern and the first mask pattern. This makes it possible to form microstructures with complex three-dimensional shapes with fewer steps.

[0009] Meanwhile, Non-Patent Document 1 (Bruce K. Gale., et. al., A review of current methods in microfluidic device fabrication and future commercialization prospects, Inventions 2018, 3(3), 60) discloses replica molding (soft lithography), injection molding, and hot embossing as the main fabrication methods for microfluidic chips. It points out that the minimum size of microstructures limited by die cutting is 25 μm, and introduces die fabrication using a 3D printer as an alternative die manufacturing method to die cutting. Die fabrication using a 3D printer can reduce the cost and time required for die fabrication, and it is disclosed that, for example, 100 parts were successfully molded using a 3D printer. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] Japanese Patent Application Publication No. 2016-028876 [Patent Document 2] Japanese Patent Application Laid-Open No. 2017-104901 [Patent Document 3] Japanese Patent Application Laid-Open No. 2014-073643 [Patent Document 4] Japanese Patent Application Laid-Open No. 2014-168777 [Patent Document 5] Japanese Patent Application Laid-Open No. 2015-130497 [Patent Document 6] Japanese Patent Application Laid-Open No. 2015-066778 [Patent Document 7] Re-table 2011 / 046169 [Non-patent literature]

[0011] [Non-Patent Document 1] Bruce K. Gale., et. al., A review of current methods in microfluidic device fabrication and future commercialization prospects, Inventions 2018, 3(3), 60 Summary of the Invention [Problem to be solved by the invention]

[0012] Here, to manufacture a microfluidic chip as a microstructure device, there is a soft lithography technology in which, for example, silicone resin (e.g., polydimethylsiloxane, PDMS) is poured into a mold having a fine pattern (microstructure) corresponding to the microstructure, the silicone resin is crosslinked using heat or light, and then the mold is released from the mold to create a molded object with a transferred fine pattern as a microfluidic chip.

[0013] Furthermore, to manufacture resin molded products larger than microfluidic chips, there is an injection molding technique in which a molten thermoplastic resin is heated and melted and poured into a metal mold to produce a resin molded product with a molded image.

[0014] However, in recent years, there has been a demand for high-mix, low-volume production of microfluidic chips. While soft lithography technology can shorten manufacturing time, it comes at a high manufacturing cost. Therefore, for example, universities and research institutes wanting to easily change the design of microstructures in microfluidic chips for experiments and testing face the costly challenge. Furthermore, soft lithography is limited to silicone resins such as PDMS, which have the drawback of absorbing hydrophobic small molecules, making them unsuitable for basic experiments and testing of microstructures. On the other hand, injection molding technology offers low manufacturing costs and allows for large production volumes, but it is difficult to transfer microstructures, limiting the production of microfluidic chips with high-precision microstructures.

[0015] The technology described in Patent Document 1 allows for the rapid mass production of resin molded products by easily manufacturing resin molds using a 3D printer. The technology described in Patent Document 2 allows for the rapid mass production of metal press-molded products by easily manufacturing resin molds using a 3D printer. However, the manufacturing precision of resin molded products is limited to approximately 100 μm, making it impossible to achieve the manufacturing precision of approximately 1 μm required for the microstructures of microfluidic chips.

[0016] Furthermore, the technology described in Patent Document 3 makes it possible to transfer nano-level fine patterns to resin. The technology described in Patent Document 4 makes it possible to manufacture nano-level structures. The technology described in Patent Document 5 makes it possible to manufacture molecular membranes. However, the manufacturing precision of these technologies is at the nano-level, which differs from the manufacturing precision of about 1 μm required for the microstructures of microfluidic chips, and therefore, as mentioned above, they cannot be applied to the manufacture of microfluidic chips.

[0017] Furthermore, the technology described in Patent Document 6 makes it possible to manufacture a laminate in which a hard coat layer, a transparent substrate, and an injection molding resin are integrated, but these laminates cannot be applied to the manufacture of microfluidic chips. Furthermore, the technology described in Patent Document 7 makes it possible to manufacture microstructures with complex three-dimensional shapes, but requires additional processes to manufacture microstructure devices. Furthermore, the technology described in Non-Patent Document 1 has the problem of limited precision in microstructures.

[0018] Therefore, the above-mentioned problems cannot be solved by the techniques described in the above-mentioned Patent Documents 1 to 6 and Non-Patent Document 1. Furthermore, similar problems exist not only in the manufacture of microfluidic chips but also in the manufacture of microstructure devices including IoT devices.

[0019] Therefore, the present invention has been made to solve the above-mentioned problems, and aims to provide a microstructure device manufacturing system and a microstructure device manufacturing method that can quickly and accurately manufacture microstructure devices that require small-lot production of a wide variety of products using soft lithography and an injection molding machine. [Means for solving the problem]

[0020] A microstructure device manufacturing system according to the present invention includes a microchannel design unit, a resin mold manufacturing unit, a structure molding unit, and a parts assembly unit. The microchannel design unit creates three-dimensional design data for a predetermined microchannel, including a channel with a side surface that slopes upward from the bottom, in accordance with a user's operational instructions. The resin mold manufacturing unit uses photolithography to manufacture a resin mold made of a photocurable resin with the microchannels in the created three-dimensional design data as convex portions. The structure molding unit places the resin mold inside an injection molding die of an injection molding machine and injects molten resin into the injection molding die to form a microchannel structure in which the microchannels in the resin mold are transferred as concave portions. The resin mold is then removed from the top surface of the microchannels in the microchannel structure to remove the microchannel structure. The parts assembly unit performs predetermined processing on the removed microchannel structure and incorporates predetermined parts to manufacture a microstructure device having the microchannel.

[0021] The microstructure device manufacturing method according to the present invention includes a microchannel designing step, a resin mold manufacturing step, a structure molding step, and a component assembling step. Each step of the microstructure device manufacturing method according to the present invention corresponds to each part of the microstructure device manufacturing system according to the present invention. [Effects of the Invention]

[0022] According to the present invention, it is possible to rapidly and accurately manufacture microstructure devices, which are required to be produced in small quantities and in a wide variety of products, using photolithography and an injection molding machine. [Brief explanation of the drawings]

[0023] [Figure 1] 1 is a schematic diagram and a functional block diagram of an example of a microstructure device manufacturing system according to an embodiment of the present invention; [Figure 2] 1 is a diagram showing an example of a procedure for executing a microstructure device manufacturing method according to an embodiment of the present invention. [Figure 3] FIG. 3A shows an example of a case where the microchannel design unit creates three-dimensional design data, and FIG. 3B shows an example of a case where the resin mold manufacturing unit manufactures a resin mold made of photocurable resin. [Figure 4] FIG. 4A shows an example of the structure molding unit molding and removing a microchannel structure, and FIG. 4B shows an example of the component assembly unit manufacturing a microfluidic chip. [Figure 5] 1A and 1B are diagrams showing examples of various microchannels in a microfluidic chip. [Figure 6] 1 is a graph comparing the microstructure device manufacturing method according to the embodiment of the present invention with other manufacturing methods in terms of manufacturing cost (manufacturing quantity) and manufacturing period. [Figure 7] 7A shows a perspective view and a cross-sectional view of an example of a resin mold of a reference example and an example of a resin mold of a comparative example, and FIG. 7B shows an example of an electron microscope photograph of the resin mold of the comparative example. [Figure 8] 8A is a diagram showing an example of measuring a release resistance value, and FIG. 8B is a photograph showing an example of measuring a release resistance value. [Figure 9] 10 is a graph showing the relationship between the total contact area and the mold release resistance value in the reference example and the comparative example. [Figure 10] 10A shows a perspective view and a cross-sectional view of an example of a resin mold of an example, and FIG. 10B shows an example of an electron microscope photograph of the resin mold of an example. [Figure 11] 10 is a graph showing the relationship between the tilt angle and the release resistance value in the comparative example and the example. DETAILED DESCRIPTION OF THE INVENTION

[0024] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings to help understand the present invention. Note that the following embodiment is an example of the present invention, and is not intended to limit the technical scope of the present invention.

[0025] As shown in FIG. 1, a microstructure device manufacturing system 1 according to an embodiment of the present invention includes a microchannel design section 10, a resin mold manufacturing section 11, a structure molding section 12, and a part assembly section 13.

[0026] Here, the microchannel design unit 10 is equipped with, for example, a terminal device having predetermined software (e.g., CAD software), and a user uses the software on the terminal device to design a desired microchannel as three-dimensional design data. Here, the microchannel includes a channel having an inclined surface (also called a tapered surface or draft gradient) whose side surface widens from the bottom to the top. Providing an inclined surface on the channel makes it easier to remove the resin from a mold, as will be described later.

[0027] The resin mold manufacturing unit 11 is equipped with, for example, a photolithography device. A user inputs three-dimensional design data into the resin mold manufacturing unit 11, which then drives the photolithography device to manufacture a resin mold (also called a mold insert) having a microchannel based on the three-dimensional design data. The photolithography device places a mask pattern corresponding to the three-dimensional design data on a substrate on which photocurable resin has been placed, irradiates the substrate with light, exposes the mask, and photocures the photocurable resin corresponding to the mask pattern, thereby forming a microchannel corresponding to the three-dimensional design data. The photolithography device can expose a microchannel corresponding to the three-dimensional design data by moving and tilting the substrate three-dimensionally.

[0028] Furthermore, the structure molding unit 12 includes, for example, an injection molding machine, and the user places a resin mold in an injection molding die (also called a mold base) of the injection molding machine and starts the structure molding unit 12, which then drives the injection molding machine to inject molten resin into the injection molding machine to form a microchannel structure onto which the resin mold is transferred, and then removes the resin mold from the top surface of the microchannel of the microchannel structure to remove the microchannel structure. Here, when removing the resin mold from the microchannel structure, the injection molding die in the direction in which the resin mold is removed is removed, and then the resin mold can be removed from the microchannel structure by pulling up the resin mold.

[0029] The parts assembly unit 13 is equipped with parts necessary for a microstructure device, and when the user installs a microchannel structure and activates the parts assembly unit 13, the parts assembly unit 13 incorporates predetermined parts into the extracted microchannel structure, thereby manufacturing a microstructure device having a microchannel. Here, the parts are appropriately set according to the type of microstructure device desired by the user.

[0030] The microchannel design unit 10, the resin mold manufacturing unit 11, the structure molding unit 12, and the part assembly unit 13 each incorporate a CPU, ROM, RAM, HDD, SSD, etc. (not shown) in their own devices, and the CPU uses, for example, the RAM as a work area to execute programs stored in the ROM, HDD, SSD, etc. Furthermore, each unit described below is realized by the CPU executing a program.

[0031] Next, a procedure for executing a microstructure device manufacturing system 1 and a microstructure device manufacturing method according to an embodiment of the present invention will be described with reference to Figures 1 and 2. Here, the manufacturing target of the microstructure device manufacturing system 1 is a microfluidic chip, one example of a microstructure device. First, a user visits the microchannel design section 10 of the microstructure device manufacturing system 1 and designs a microchannel for experiment or testing using predetermined software (CAD software) installed on the terminal device of the microchannel design section 10.

[0032] Examples of software include 3D CAD, 3D numerical calculation software, and dedicated 3D micropath design software. The microchannel to be designed in the present invention includes a channel having a side surface that slopes from the bottom to the top. Then, in accordance with the user's operational instructions, the microchannel design unit 10 creates 3D design data for a predetermined microchannel including a channel having a side surface that slopes from the bottom to the top (FIG. 2: S101).

[0033] Here, there is no particular limitation on the method for creating the microchannel design unit 10. For example, when a user inputs three-dimensional design data of a desired micropath using software on a terminal device, the microchannel design unit 10 creates three-dimensional design data of the microchannel shown in a plan view, a front cross-sectional view, and a right side cross-sectional view, as shown in Figure 3A, in accordance with the user's operational instructions. Here, for example, suppose the microchannel P created this time has a linear channel P1 inside a microfluidic chip and two truncated conical channels P2 connected to each end of the linear channel P1. The truncated conical channel P2 is configured as a channel with inclined sides P2a that widen from the bottom to the top.

[0034] Here, the angle α of the inclined surface P2a is defined as the angle between the vertical direction (height direction) of the truncated conical flow channel P2 and the inclined surface P2a, and is preferably set within a range of 0.1 to 10.0 degrees, more preferably within a range of 0.1 to 5.0 degrees, and most preferably within a range of 0.1 to 3.0 degrees. The angle α of the inclined surface P2a may be set manually by a user through an operation instruction, or may be set to a predetermined value in software.

[0035] Now, when the microchannel design unit 10 completes creation of the three-dimensional design data in response to an operation instruction from the user, the user then goes to the resin mold production unit 11 of the microstructure device manufacturing system 1 and inputs the design data to the resin mold production unit 11. Then, the resin mold production unit 11 uses photolithography to produce a resin mold made of a photocurable resin with the microchannels of the input three-dimensional design data as convex portions (FIG. 2: S102).

[0036] Here, the manufacturing method of the resin mold manufacturing unit 11 is not particularly limited. The photolithography performed by the resin mold manufacturing unit 11 is performed, for example, using a photolithography device equipped with a substrate on which photocurable resin is placed, a mask pattern, and a light source, as described above. Examples of methods that the resin mold manufacturing unit 11 can use to create shapes using photolithography and 3D design data include tilted exposure, tilted rotation exposure, direct writing, and multistage exposure. The tilted exposure method exposes the photocurable resin on the mask pattern from different directions. The tilted rotation exposure method involves placing a first mask pattern in close contact with the surface of a photocurable resin sample, placing a second mask pattern above and away from the sample surface, and exposing the sample with the first mask pattern in close contact while tilting and rotating it. The direct writing method involves directly drawing a three-dimensional shape on the sample while moving a light source. The multistage exposure method involves exposure using multiple mask patterns. These methods can be used to create microchannels based on 3D design data. Furthermore, in the present invention, the use of photolithography makes it possible to smooth the surface roughness of the microchannel, improving the quality of the subsequent microchannel structure and improving ease of demolding. Furthermore, the present invention makes it possible to manufacture microfluidic chips with integrated microchannels, which cannot be manufactured by cutting or 3D printers.

[0037] Here, for example, when the resin mold manufacturing unit 11 uses the tilted rotation exposure method, the process proceeds as follows. As shown in FIG. 3B, the resin mold manufacturing unit 11 places a photocurable resin F2 on the substrate F1 and then adheres a mask pattern F3 thereon. Here, the resin mold manufacturing unit 11 creates a mask pattern F3 having an opening F3a capable of forming a truncated cone-shaped flow path P2, for example, based on three-dimensional design data. Next, the resin mold manufacturing unit 11 places a transparent resin F3 having a refractive index (e.g., 1.51) smaller than the refractive index (e.g., 1.67) of the photocurable resin F2 on the mask pattern F3. Furthermore, the resin mold manufacturing unit 11 tilts the substrate F1 at a predetermined tilt angle β with respect to the vertical direction of the photolithography apparatus and exposes the substrate F1 while rotating it. Light L is irradiated onto the transparent resin F3 at an inclination angle β. However, due to the difference in refractive index between the transparent resin F3 and the photocurable resin F2, the light L is inclined to a smaller inclination angle γ before passing through the photocurable resin F2. This inclination angle γ corresponds to the inclination angle α of the inclined surface P2a of the truncated cone-shaped flow channel P2. In this way, the inclined surface P2a of the micro-flow channel P is formed by adjusting the inclination angle γ of the light L. The inclined surface P2a of the flow channel P to be manufactured is appropriately designed by adjusting the inclination angle β of the substrate F1, the rotation speed of the substrate F1, the exposure intensity, the refractive index of the transparent resin F3, and the refractive index of the photocurable resin F2. The photocurable resin F2 exposed to the light L hardens and adheres to the substrate F1. On the other hand, the photocurable resin F2 not exposed to the light L does not harden and is therefore removable. After completing the exposure, the resin mold manufacturing unit 11 removes the transparent resin F3, the mask pattern F3, and the photocurable resin F2, thereby obtaining a resin mold made of photocurable resin with the truncated cone-shaped flow path P2 of the microchannel P as a convex portion. The resin mold becomes photocurable resin F2a after hardening and adhered to the substrate F1.

[0038] Here, the type of photocurable resin is not particularly limited, but examples thereof include photocurable epoxy resins such as SU-8, photocurable acrylic resins, etc. Furthermore, the type of light source is not particularly limited, but examples thereof include ultraviolet light, visible light, electron beams, etc.

[0039] Although the above description has been given of a resin mold made of photocurable resin, the resin mold may be processed by a predetermined process. For example, an electroplating process may be performed to deposit metal on the photocurable resin F2a of the resin mold, thereby producing a resin mold with a photocurable resin interior and a metal exterior. The electroplating process is a process for coating the surface of the photocurable resin F2a with a thin metal film. The predetermined process is not limited to electroplating, and may also be a painting process, a surface hardening process, or the like.

[0040] Now, when the resin mold manufacturing section 11 completes manufacturing the resin mold, the user then goes to the structure molding section 12 of the microstructure device manufacturing system 1 and sets the resin mold in the structure molding section 12. Then, the structure molding section 12 sets the resin mold inside the injection molding die of the injection molding machine, and injects molten resin into the injection molding die to form a microchannel structure in which the microchannels of the resin mold are transferred as recesses, and then removes the resin mold from the top surface of the microchannels of the microchannel structure to take out the microchannel structure (FIG. 2: S103).

[0041] Here, there are no particular limitations on the molding method of the structure molding unit 12. For example, the structure molding unit 12 places a resin mold PM inside an injection molding die IM. As described above, the resin mold PM is a photocurable resin F2a applied to a substrate F1 after hardening, and the injection molding die IM is designed to surround this resin mold PM. The injection molding die IM is configured to be openable and is appropriately designed depending on the type of molten resin to be injected inside. For example, if the molten resin is a thermoplastic resin such as cycloolefin polymer (COP), polyethylene (PE), polypropylene (PP), polystyrene (PS), polyvinyl chloride (PVC), ABS resin, AS resin, polyethylene terephthalate (PET), polytetrafluoroethylene (PTFE), or polymethacrylic (PMMA), the injection molding die IM is composed of a lower plate, a middle plate, and an upper plate made of metal. The structure molding unit 12 then places a resin mold PM on the lower plate, places a middle plate on top of that, and places an upper plate on top of that, and fastens the lower plate, resin mold PM, middle plate, and upper plate together with fastening means such as bolts. Next, the structure molding unit 12 heats the injection molding die IM for the lower plate, middle plate, and upper plate to maintain the temperature of the injection molding die within a predetermined temperature range. Furthermore, the structure molding unit 12 injects molten resin through pre-drilled holes in the heated injection molding die, allowing the molten resin to penetrate between the resin mold PM and the injection molding die IM. The structure molding unit 12 holds the injection molding die IM for a predetermined time, then cools the injection molding die IM to maintain the temperature of the injection molding die IM within a predetermined temperature range. This allows the molding of a microchannel structure S in which the microchannels of the resin mold PM are transferred as recesses. The microchannel structure S is a structure formed by solidifying the molten resin and becomes a component of a microfluidic chip. Then, the structure molding section 12 opens the injection molding die IM and removes the resin mold PM from the upper surface of the minute channel (here, the truncated cone-shaped channel P2) of the minute channel structure S, thereby taking out the minute channel structure S.

[0042] Here, by providing the inclined surface P2a on the truncated cone-shaped channel P2 of the micro-channel P, the mold release resistance of the resin mold PM from the micro-channel structure S is smaller than when the side surface of the truncated cone-shaped channel P2 is flat. Therefore, when the structure molding unit 12 removes the resin mold PM, it can be easily removed without applying an unnecessary load to the micro-channel structure S. This allows the micro-channel structure S to be manufactured with high precision without causing molding defects such as burrs on the micro-channel structure S, fragments of the resin mold PM remaining in the micro-channels of the micro-channel structure S, damage to the micro-channel structure S or the resin mold PM, or destruction of the micro-channels, which are the main components of the microfluidic chip. In other words, by configuring the micro-channel P with the inclined surface P2a, the ease of mold release is improved.

[0043] Furthermore, since the present invention uses photolithography, the surface roughness of the photocurable resin F2a of the resin-type PM is smoothed, which improves the ease of demolding when removing the resin-type PM from the microchannel structure formed by injection molding, making it possible to remove the resin-type PM with high precision.

[0044] Furthermore, when the structure molding section 12 removes the resin mold PM, by keeping the mold temperature within a predetermined temperature range, the micro-channel structure S can be removed while further suppressing the mold release resistance value between the injection molding mold IM and the resin mold PM.

[0045] Furthermore, in the above configuration, the molten resin penetrates into the resin-type PM and solidifies, so for example, it is preferable that the melting point of the molten resin is lower than the melting point of the photocurable resin F2 of the resin-type PM.

[0046] In the above description, the molten resin is a thermoplastic resin, but the present invention is not limited to this. For example, the molten resin may be a silicone elastomer (silicone resin) such as polydimethylsiloxane (PDMS).

[0047] Furthermore, in the above description, a micro-channel structure S having a truncated cone-shaped channel P2 has been described, but this is not limiting, and a micro-channel structure S having a linear channel P1 can also be formed by the same method as described above.

[0048] Now, when the structure molding section 12 has completed molding of the microchannel structure S, the user finally goes to the component assembly section 13 of the microstructure device manufacturing system 1 and places the microchannel structure S in the component assembly section 13. Then, the component assembly section 13 performs predetermined processing on the extracted microchannel structure S and incorporates predetermined components to manufacture a microfluidic chip T having a microchannel P (FIG. 2: S104).

[0049] Here, the manufacturing method of the parts assembly unit 13 is not particularly limited. Since the micro-channel structure S is formed with micro-channels P (frustum-shaped channels P2) by infiltrating molten resin, molded portions other than the desired micro-channels P are generated. Therefore, the parts assembly unit 13 processes the unnecessary molded portions S0, for example, as shown in FIG. 4B . Then, the parts assembly unit 13 processes the surface of the remaining micro-channel structure S using a surface modification method (e.g., oxygen plasma method, VUV method, etc.). In addition, the parts assembly unit 13 brings in another micro-channel structure S having a linear channel P1 that has been molded in advance, bonds the micro-channel structure S having the truncated cone-shaped channels P2 to the micro-channel structure S having the linear channel P1, and connects the truncated cone-shaped channels P2 to both ends of the linear channel P1. In addition, the parts assembly unit 13 can manufacture a microfluidic chip T by attaching a predetermined film (e.g., a cycloolefin film, etc.) to the surface of the microchannel structure S after bonding, or by incorporating a predetermined circuit (e.g., an oscillator, etc.).

[0050] As described above, the present invention enables the rapid and highly accurate manufacture of microfluidic chips T, which require high-mix, low-volume production, using soft lithography and an injection molding machine. Furthermore, the present invention does not require the material to be limited to silicone elastomers such as PDMS, and general molten resins can be used. This allows universities and research institutions to conduct basic experiments and tests on microchannels with high accuracy, regardless of the material, and will promote innovation in microfluidic chips T. Furthermore, the present invention enables the creation of microstructures with higher accuracy compared to conventional methods of creating microstructures by cutting molds, and it also enables the creation of microstructures at the same cost and time as methods using 3D printers.

[0051] In particular, at universities and research institutes, the specifications of the microfluidic chip T for basic experiments and tests are unclear and subject to frequent changes. Therefore, by using the present invention, it is possible to facilitate the concretization of the unclear specifications of the microfluidic chip T, and since mass production is possible with the use of a resin-type PM, iterative development is facilitated, enabling gradual improvement in the completeness of the microfluidic chip T and the realization of an agile development method.

[0052] Furthermore, in the present invention, the microfluidic chip T can be manufactured by resin molding processing based on photolithography and injection molding, so even universities and research institutions that find it difficult to make large capital investments can easily manufacture resin-type PMs and manufacture the microfluidic chips T they desire.

[0053] While the microfluidic chip T has been described above as an example of a microchannel P, a configuration in which a linear channel P1 and two truncated cone-shaped channels P2 are provided inside the microfluidic chip T is not limited thereto. For example, as shown in FIG. 5, the microchannel P may be a Y-shaped channel PY, or a cylindrical channel P3 connected to both ends of the linear channel P1 and protruding outward. The cylindrical channel P3 may be fitted with, for example, the injection part of a syringe. Alternatively, the microchannel P may be a combination of a U-shaped channel P4 that branches into two channels and a W-shaped channel P5 that branches into three channels. Alternatively, the microchannel P may be a combination of a linear channel P1 that is wide in the width direction and two truncated cone-shaped channels P2. Some or all of the side surfaces of these microchannels P may be provided with inclined surfaces that widen from the bottom to the top.

[0054] Now, regarding the subject of the present invention, as shown in FIG. 6, in a graph with the vertical axis representing the manufacturing period and the horizontal axis representing the manufacturing cost (production volume), typical injection molding methods fall into region B, where the manufacturing period is long but the manufacturing cost is low. This region B is suitable for mass production. Meanwhile, cutting-edge manufacturing methods using micromilling, laser ablation, and 3D printers fall into region C, where the manufacturing period is short but the manufacturing cost is high. This region C is suitable for small-scale production or prototype development. However, even within region B, it is understood that region C cannot accommodate a region with a medium manufacturing period and medium manufacturing cost (medium manufacturing volume). On the other hand, the present invention falls into region A, where the manufacturing period is short, the manufacturing cost is low, and the manufacturing volume is capable of accommodating products of approximately 10 to 100 units. Thus, the present invention can accommodate region A, which differs from typical injection molding and cutting-edge manufacturing methods, and is therefore superior to conventional methods.

[0055] In particular, when universities and research institutions (e.g., pharmaceutical companies) investigate the toxicity and pharmacological efficacy of a given substance, microfluidic chips T must be molded to fit the context of use (COU). This COU is not predetermined but varies, for example, based on discussions between researchers and developers involved in drug discovery. Therefore, universities and research institutions must modify the design of the microchannels P to develop and validate appropriate analytical methods based on this COU. Attempting to mold microfluidic chips to fit the COU using the conventional methods described above results in long construction times and enormous costs, making them impractical. This hinders the widespread use of microfluidic chips T as an alternative to experimental animals. The present invention offers advantages in terms of manufacturing time, manufacturing cost, and production volume, making it possible to mold microfluidic chips to fit the currently required COU, which is believed to contribute to the widespread use of microfluidic chips T. [Example]

[0056] Examples and comparative examples of the present invention will be specifically described below, but the application of the present invention is not limited to these examples. <Reference Examples and Comparative Examples>

[0057] First, molten resin was injected into the inside of the injection molding die IM to form a micro-channel structure S in which the micro-channels of the resin mold PM were transferred, and the mold release resistance value that occurred when the resin mold PM was removed from the top surface of the micro-channels of the micro-channel structure S was measured.

[0058] Here, as shown in FIG. 7A, a resin mold without any cured photocurable resin F2a on the substrate F1 was used as a reference example (contact area without structure), and a resin mold with 200 μm diameter cylinders on the substrate F1 as the cured photocurable resin F2a, arranged in a grid pattern with 500 μm intervals, was used as a comparative example (contact area with structure). The resin mold of the comparative example was obtained by transferring a cylinder mask pattern to a glass substrate, applying and setting a negative photocurable resin photoresist (SU-8), and then back-exposing the glass substrate. FIG. 7B shows an example of an electron microscope photograph of the resin mold of the comparative example. As shown in FIG. 7B, it can be seen that the cylinders that become the convex portions of the microchannels are arranged in a grid pattern at predetermined intervals. In the comparative example, in order to change the structural parameters of the convex portion of the microchannel, the surface area of ​​the cylinder (for example, bottom circle diameter 16 mm, 20 mm, 24 mm) was changed by controlling the exposure range of the mask pattern, and the height of the cylinder (50 μm, 100 μm) was changed by controlling the film thickness of the applied photocurable resin, thereby producing multiple types of resin molds.

[0059] Next, as shown in Figure 8A, the prepared resin mold PM was placed in an injection molding die IM manufactured using a 3D printer. A hex bolt B with grippers at both ends was attached to the injection molding die IM, and molten PDMS resin was poured into the injection molding die IM for injection molding. Here, in the Reference Example, the absence of a cylinder resulted in no lateral area of ​​the convex portion of the microchannel. However, in the Comparative Example, the presence of a cylinder resulted in the convex portion of the microchannel, increasing its lateral area and increasing the contact area with the PDMS. The injection molding die IM was then disassembled, and the resin mold PM, solidified PDMS, and hex bolt B were removed from the assembly. The hex bolt B was attached to the gripper of a commercially available precision universal testing machine H. The resin mold PM was then attached to the platform of the precision universal testing machine H. The gripper was then pulled upwards to remove the PDMS solidified on the hex bolt B from the resin mold PM. In this case, the peel force when the PDMS was released from the resin mold PM was measured as a tensile force, and the effect of the microchannel structure of the resin mold PM on the release was confirmed. Figure 8B shows an example of when hexagonal bolt B is attached to the gripping part of precision universal testing machine H, the resin mold PM is attached to the base of precision universal testing machine H, and the gripping part is pulled.

[0060] As a result, as shown in Figure 9, it can be seen that in both the Reference Example and the Comparative Example, the mold release resistance value (mold release force (N)) increases as the total contact area (mm2) increases. Furthermore, it can be seen that the Comparative Example, in which the microchannel has a convex portion, has a larger mold release resistance value than the Reference Example. In this way, it can be seen that in injection molding to create microchannels, the contact area between the molten resin and the microchannel in the resin mold PM has a significant effect on the ease of mold release. <Example>

[0061] Next, we focused on the shape of the microchannel, and measured the mold release resistance when the microchannel was provided with an inclined surface whose side surface widened from the bottom surface to the top surface.

[0062] As shown in FIG. 10A, a truncated conical channel P2 was assumed as the microchannel P, and an inclined surface P2a was provided on the side of the truncated conical channel P2. The angle α of the inclined surface P2a was defined as the angle between the vertical direction (height direction) of the truncated conical channel P2 and the inclined surface P2a. To form this truncated conical channel P2, a mask pattern was provided with circles with a diameter of 500 μm spaced at intervals of 500 μm between their centers. Then, using an inclined rotation exposure method, cured photocurable resin F2a corresponding to the truncated conical channel P2 was applied to a substrate F1 to fabricate the resin mold PM of the example. Here, the height of the cured photocurable resin F2a was 50 μm, and the inclination angle α of the inclined surface P2a of the truncated conical channel P2 was set between 1.0 and 6.0 degrees. FIG. 10B shows an example of an electron microscope photograph of the resin mold of the example. As shown in Figure 10B, it can be seen that there is an inclined surface on the truncated cone that forms the convex portion of the microchannel. From this electron microscope image, the upper and lower circular diameters, film thickness, and inclination angle of the fabricated truncated cone were measured. These measured values ​​were used to estimate the contact area between the truncated cone structure of the microchannel and the molten resin (PDMS).

[0063] Next, as described above, the resin mold PM and hex bolt B of the example were placed in the injection molding mold IM, and molten PDMS resin was poured into the injection molding mold IM to perform injection molding. The injection molding mold IM was then disassembled, and hex bolt B was attached to the gripper of a precision universal testing machine H. The resin mold PM was then attached to the platform of the precision universal testing machine H, and the gripper was pulled upwards to remove the solidified PDMS from the resin mold PM. The mold release resistance at this time was measured. The diameter of the entire contact area between the microstructure of the molten resin (PDMS) and the contact surface of the injection molding mold (SU-8) was defined as the base diameter, and the effect of the entire contact area was also confirmed by adjusting the base diameter from 16 mm to 24 mm.

[0064] As a result, Figure 11 is a graph showing the relationship between the inclination angle and the demolding resistance for the comparative example and the example. In Figure 11, the case where the inclination angle is 0 degrees corresponds to the comparative example, and the case where the inclination angle is greater than 0 degrees corresponds to the example. As shown in Figure 11, the demolding resistance decreases as the inclination angle increases. Furthermore, it can be seen that the demolding resistance at an inclination angle of approximately 3 degrees is almost equivalent to that at an inclination angle of approximately 6 degrees. In other words, since the demolding resistance becomes constant once the inclination angle exceeds a certain angle, it can be seen that setting the inclination angle up to a certain angle can improve the ease of demolding. Furthermore, the effect of the inclination angle is similar even when the bottom diameter is small. It can be seen that increasing the inclination angle reduces the demolding resistance and improves the ease of demolding. Thus, in injection molding to fabricate microchannels, it can be seen that by creating a microchannel with inclined sides that widen from the bottom to the top, the demolding resistance is reduced and the ease of demolding is improved. In other words, this leads to higher precision in microchannels.

[0065] In the above description, a microfluidic chip was mentioned as an example of a microstructure device, but the present invention is not limited to this and can be applied to IoT devices (devices in the IoT that are connected to each other, via a LAN, or the Internet, and communicate information and control). [Industrial Applicability]

[0066] As described above, the microstructure device manufacturing system and microstructure device manufacturing method of the present invention are useful in the fields of research and development of microphysiological systems (MPS), research and development of pharmaceuticals, medicine, biotechnology, chemical analysis, etc., and the fields of remotely controlled home appliances, lighting devices, air conditioning devices, mobile terminal devices, and running devices such as automobiles, and are effective as a microstructure device manufacturing system and microstructure device manufacturing method that can quickly and accurately manufacture microstructure devices that require small-lot production of a wide variety of products using photolithography and injection molding machines. [Explanation of symbols]

[0067] 1. Microstructure device manufacturing system 10 Microchannel Design Department 11 Resin mold manufacturing department 12 Structure molding section 13 Parts Assembly Department

Claims

1. a microchannel design unit that creates three-dimensional design data for configuring a predetermined microchannel including a channel having a side surface with an inclined surface that widens from the bottom surface toward the top surface in accordance with a user's operation instruction; a resin mold manufacturing unit that uses photolithography to manufacture a resin mold made of a photocurable resin with the microchannels of the three-dimensional design data formed as convex portions; a structure molding section that places the resin mold inside an injection molding die of an injection molding machine, injects molten resin into the injection molding die, thereby molding a micro-channel structure in which the micro-channels of the resin mold are transferred as recesses, and removes the resin mold from an upper surface of the micro-channels of the micro-channel structure, thereby removing the micro-channel structure; a parts assembly unit that performs predetermined processing on the extracted microchannel structure and incorporates predetermined parts to manufacture a microstructure device having the microchannel; Equipped with The parts assembly unit processes a micro-channel structure having micro-channels including truncated cone-shaped channels by removing unnecessary molded portions, processes the surface of the remaining micro-channel structure by using a surface modification method, bonds the surface of the micro-channel structure to the surface of another micro-channel structure having other micro-channels including linear channels that have been formed in advance, connects the micro-channels of the micro-channel structure to the other micro-channels of the other micro-channel structure, and attaches a predetermined film or incorporates a predetermined circuit onto the surface of the micro-channel structure after bonding. Microstructure device manufacturing system.

2. a microchannel design process for creating three-dimensional design data for configuring a predetermined microchannel including a channel having a side surface with an inclined surface that widens from the bottom surface toward the top surface in accordance with a user's operation instruction; a resin mold manufacturing process in which a resin mold made of a photocurable resin is manufactured using photolithography, with the microchannels of the three-dimensional design data formed as convex portions; a structure molding step of placing the resin mold inside an injection molding die of an injection molding machine, injecting molten resin into the injection molding die to mold a micro-channel structure in which the micro-channels of the resin mold are transferred as recesses, and removing the resin mold from an upper surface of the micro-channels of the micro-channel structure to remove the micro-channel structure; a parts assembly process in which predetermined parts are incorporated into the extracted microchannel structure to manufacture a microstructure device having the microchannel; Equipped with The component assembly process includes removing unnecessary molded portions from a micro-channel structure having micro-channels including truncated cone-shaped channels, processing the surface of the remaining micro-channel structure using a surface modification method, bonding the surface of the micro-channel structure to the surface of another micro-channel structure having other micro-channels including linear channels that have been formed in advance, connecting the micro-channels of the micro-channel structure to the other micro-channels of the other micro-channel structure, and attaching a predetermined film or incorporating a predetermined circuit to the surface of the micro-channel structure after bonding. A method for manufacturing a microstructure device.

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