Micro-channel chip and manufacturing method thereof

Abstract

The invention provides a micro-channel chip and a manufacturing method thereof. The micro-channel chip can restrain light noise from the inside of a channel, can store leaked liquid from an injection port part and a discharge port part, and enables substrates to be laminated and integrally bonded without using an adhesive. A micro-channel chip (3) according to the present invention is formed in a translucent plate shape and has a channel groove (12) sealed therein except for an injection port (22) and a discharge port (22), and is characterized by comprising: a first substrate (1) having a channel groove formed thereon and having a first bonding surface (11) for being integrally bonded to the second substrate in a stacked manner, and a second substrate (2) having a second bonding surface (12) for being bonded to the second substrate in a stacked manner; the first substrate has a first bonding surface (21) for laminating and integrally bonding with the first substrate, a recess (13) not communicating with the flow channel groove is formed on the first substrate, the second substrate has a second bonding surface (21) for laminating and integrally bonding with the first substrate, at least one of an injection port communicating with the flow channel groove and a discharge port communicating with the flow channel groove is formed on the second substrate, and an opening (23) connected with the recess is formed on at least one of the first substrate and the second substrate.

Description

Technical Field

[0001] The present invention relates to a microfluidic chip in which bonding surfaces of opposing substrates are bonded to form a microfluidic channel therebetween and a method for manufacturing the same. Background Art

[0002] A microfluidic chip is a molded product that has microfluidic channels with a width of several hundred nanometers to less than 1 mm between two or more substrates bonded and joined. Reagents or samples are injected from holes connected to the channels for sample separation, analysis, detection, etc.

[0003] As the use of microfluidic chips, typical uses include analysis or synthesis of compounds in the field of medicine and pharmacy, environmental measurement, etc. When the microfluidic chip is used for these purposes, for example, an effect such as being able to shorten the analysis time can be obtained compared with the use of existing analysis devices suitable for similar purposes.

[0004] In recent years, attempts have been made to configure multiple flow channels on a chip and measure different samples or different reagents at the same time, thereby increasing the number of measurements that can be made at one time and improving the efficiency of measurement and inspection. In addition, a product that allows ordinary users other than medical professionals to add liquids or obtain analysis results is expected.

[0005] When manufacturing a microfluidic chip, a method for bonding resin substrates to each other is important. For example, Patent Document 1 is known as a bonding method that can bond resins to each other at a lower temperature than bonding by thermal fusion.

[0006] (Prior art literature)

[0007] (Patent Document)

[0008] (Patent Document 1) Japanese Patent No. 4919474 Summary of the invention

[0009] (Technical issues to be solved)

[0010] However, when bonding is performed without using an adhesive, there is a problem that bubbles enter between the bonding surfaces and liquid leaks from the bonding surfaces of the flow channel portion.

[0011] In view of the above problems, an object of the present invention is to provide a microfluidic chip and a method for manufacturing the same which can improve the introduction of bubbles when bonding without using an adhesive and can store liquid leaking from an injection port and an outlet outside the flow channel.

[0012] (Solution to the problem)

[0013] A microfluidic chip of one embodiment of the present invention that can solve the above-mentioned problems is formed in a light-transmitting plate shape and has a flow channel sealed inside except for an injection port and a discharge port, and is characterized in that the microfluidic chip includes a first substrate and a second substrate, the first substrate is formed with a flow channel, has a first bonding surface for being stacked and integrally bonded with the second substrate, and has a recess that is not connected to the flow channel, the second substrate has a second bonding surface for being stacked and integrally bonded with the first substrate, is formed with at least one of an injection port connected to the flow channel or a discharge port connected to the flow channel, and an opening connected to the recess is formed on at least one of the first substrate and the second substrate.

[0014] In addition, although not limited to the present embodiment, preferably, the opening portion is formed in the second substrate in the same direction as the recessed portion.

[0015] In addition, although not limited to the present embodiment, it is preferred that the opening portion is formed in a side surface of at least one of the first substrate and the second substrate.

[0016] In addition, although not limited to this embodiment, it is preferred that the area of ​​the recessed portion is larger than the area of ​​the opening portion.

[0017] Although not limited to this embodiment, it is preferred that a gradient is formed on at least a portion of the side surface of the recess.

[0018] In addition, although not limited to this embodiment, it is preferred that the depth of the recessed portion from the first joint surface is deeper than the depth of the flow channel groove.

[0019] In addition, although not limited to this embodiment, preferably, the edge of the opening is formed in a manner lower than the edge height of one of the injection port or the discharge port, the edge height difference is greater than 0.1 μm, and a corner recess is formed that is thinner than the thickness of the second substrate.

[0020] Although not limited to the present embodiment, it is preferred that a plurality of openings are formed, and the corner recessed portion communicates with the plurality of openings.

[0021] In addition, although not limited to this embodiment, preferably, there is no adhesive layer or adhesion layer on the first joint surface and the second joint surface.

[0022] Although not limited to the present embodiment, it is preferred that a plurality of flow channel grooves are independently arranged, and recessed portions are arranged between the flow channel grooves.

[0023] In addition, although not limited to this embodiment, it is preferred that an optical measurement observation surface is formed on the second substrate, and the second substrate is located above the flow channel groove formed on the first substrate.

[0024] In addition, in a method for manufacturing a microfluidic chip according to another embodiment of the present invention, the microfluidic chip is formed into a light-transmitting plate and has a flow channel groove sealed inside except for an injection port and a discharge port. The microfluidic chip includes a first substrate and a second substrate. The first substrate is formed with a flow channel groove, has a first bonding surface for being stacked and integrally bonded with the second substrate, and has a recessed portion that is not connected to the flow channel groove. The second substrate has a second bonding surface for being stacked and integrally bonded with the first substrate, and has at least one of an injection port connected to the flow channel groove or a discharge port connected to the flow channel groove. An opening portion connected to the recessed portion is formed on at least one of the first substrate and the second substrate.

[0025] (Effects of the Invention)

[0026] As described above, according to the present invention, a microfluidic chip and a method for manufacturing the same can be provided, in which, even if bubbles remain between two bonding substrates during the process of bonding the bonding surfaces, the remaining bubbles at the bonding surfaces can be removed by using the opening portion as a degassing hole, and in addition, when liquid leaks from the injection port and the discharge port, the liquid can flow into the groove of the recessed portion and be stored.

[0027] In a preferred aspect of the present invention, the area of ​​the opening is smaller than that of the recess, so that the opening becomes a burr portion for the liquid accumulated in the recess groove, thereby making it difficult for the liquid to overflow.

[0028] Furthermore, in a preferred aspect of the present invention, an angle is set on the side surface of the recess to suppress scattered light from the sample from being refracted or totally reflected by the gradient portion and returning to the flow channel, thereby reducing noise light entering other flow channel portions. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 1 is an explanatory diagram showing a state of an example of the configuration of the microfluidic chip when viewed from the second substrate side.

[0030] Figure 2 It is a cross-sectional schematic diagram showing the function of the microfluidic chip.

[0031] Figure 3 Schematic diagram showing an example of the opening portion of the microfluidic chip.

[0032] Figure 4 Schematic diagram showing an example of the opening portion of the microfluidic chip.

[0033] Figure 5 Schematic diagram showing an example of the opening portion of the microfluidic chip.

[0034] Figure 6 It is a schematic diagram showing the function of the opening of the microfluidic chip.

[0035] Figure 7 This is an explanatory diagram showing that a plurality of flow channel grooves and recessed portions are formed in the micro-fluidic chip.

[0036] Figure 8 It is a schematic cross-sectional view showing a gradient portion on the side surface of a recess of a microfluidic chip.

[0037] Fig. 9 2 is a diagram showing an example of a height difference of an edge surface of an opening portion.

[0038] Fig.10 It is a cross-sectional view showing the function of the opening portion in the bonding step.

[0039] Fig.11 It is a cross-sectional view showing an example of the arrangement and height difference of the flow channel grooves and the recessed portion according to the present embodiment. DETAILED DESCRIPTION

[0040] Hereinafter, with respect to the embodiments of the present invention, the preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention can be implemented in a variety of different ways and is not narrowly limited to the examples of the embodiments and embodiments shown below. The dimensions, materials and other specific numerical values ​​shown in the embodiments are only examples for easy understanding of the present invention and do not limit the present invention unless otherwise specified. In addition, in this specification and the accompanying drawings, for elements having substantially the same function and structure, repeated descriptions are omitted by assigning the same figure marks, and illustrations of elements that are not directly related to the present invention are omitted. In the accompanying drawings, directions such as XYZ are marked to define directions.

[0041] Figure 1 1 is a schematic diagram of a microfluidic chip (hereinafter, simply referred to as “microfluidic chip”) 3 according to the present embodiment. Figure 2 2 is a schematic cross-sectional view of the microfluidic chip 3. More specifically, the microfluidic chip 3 is formed by stacking a first substrate 1 and a second substrate 2 and integrally bonding them.

[0042] The bonding surface 11 of the first substrate 1 is formed with a sealed flow channel 12 except for the injection port 22 and the discharge port 22, and a recess 13 not connected to the flow channel 12. The bonding surface 21 of the second substrate 2 is formed with an opening 23 that opens upward similarly to the injection port 22 and the discharge port 22.

[0043] In addition, in the microfluidic chip 3 according to the present embodiment, the substrate 1 formed with the flow channel groove 12 and the recess 13 is called the "first substrate", and the other substrate stacked with the first substrate is called the "second substrate", but "first" and "second" are only quantifiers used to distinguish the two substrates when describing the microfluidic chip according to the present embodiment, and have no other technical meanings. Of course, it is not denied that not only the recess can be set on the first substrate, but also the recess can be set on the second substrate. That is, the flow channel groove 12 and the recess 13 can also be formed on the bonding boundary surface 31 between the bonding surface 11 of the first substrate 1 and the bonding surface 21 of the second substrate 2. In addition, in the microfluidic chip 3 according to the present embodiment, multiple recesses 13 can also be formed on the first substrate 1.

[0044] In addition, in the microfluidic chip 3 according to the present embodiment, an injection port 22 and a discharge port 22 are formed on the second substrate 2. The injection port 22 and the discharge port 22 are connected to the flow channel groove 12, and liquid can be injected from the injection port 22 and discharged from the discharge port 22 via the flow channel groove 12. In addition, it is preferred that both the injection port 22 and the discharge port 22 are provided on the bonding surface 21 of the second substrate, but it is not limited thereto, as long as at least one of them is formed on the second substrate 2.

[0045] Furthermore, it is important for the microfluidic chip 3 to have light transmittance. If there are no particular problems with the required heat resistance and durability, a resin that is more suitable for mass production in terms of the manufacturing method is selected as the material, but glass with excellent transmittance is also a preferred example.

[0046] In the microfluidic chip 3, the resin as the main component is preferably a polymer material that can be processed and molded into a desired shape. As described below, the resin used for the first substrate 1 is not limited as long as the desired refractive index can be obtained, for example, thermoplastic resins such as polycarbonate, polyethylene, polypropylene, polyvinyl chloride, polyester, acrylic acid, cycloolefin polymer (COP) and cycloolefin copolymer (COC), thermosetting resins such as phenolic resin, polyurethane and thermosetting polyimide, or photocurable resins can be cited.

[0047] Furthermore, the resin is not limited as long as it is light-transmissive, and may be colorless and transparent, colorless and translucent, colored and transparent, or colored and translucent.

[0048] In addition, each substrate before bonding can be produced by various molding methods such as injection molding using a mold formed with fine flow channels and convex portions. In addition, the thickness of the substrate is not limited and it can also be a thin film.

[0049] In the microfluidic chip 3 according to the present embodiment, the size of the flow channel 12 is not limited as long as it can function as a microfluidic chip, and various widths and shapes can be adopted, but the typical preferred range is considered to be a width of greater than 0.1 μm and less than 1 mm, and a depth of greater than 0.1 μm and less than 1 mm.

[0050] In addition, regarding the production of fine concave and convex parts of flow channels and other grooves, generally known methods are molds that process metals by cutting, methods that combine electron beam etching and plasma etching, and methods of production by optical lithography. The formed fine structure can also be formed as an electroforming mold. The fine concave and convex parts of the formed flow channel groove can be transferred to a resin or the like as a mold, thereby enabling mass production.

[0051] The injection port 22, the discharge port 23, and the opening 23 that penetrates the second substrate 2 can be formed by molding with a mold structure, additional processing by cutting, pressing, laser processing, etc., as desired.

[0052] Furthermore, since a cover is provided on the flow channel 12 in order to prevent the liquid from overflowing outside the necessary flow channel 12, the substrates are bonded to each other in the bonding step.

[0053] In addition, in this embodiment, an example is shown in which the recess 13 and the opening 23 connected thereto are in the same direction. The advantage of this arrangement is that even if the liquid leaks from the injection port and the discharge port 22 formed on the second substrate 2, the liquid can be stored in the recess 13 from the opening 23, but it is not necessarily necessary to be in the same direction, as long as the opening 23 connected to the recess 13 is formed on the first substrate 1 and the second substrate 2. In addition, the "same direction" here means that when the microfluidic chip 3 according to this embodiment is observed, it is formed on the same surface layer side.

[0054] Furthermore, here, as an example of another embodiment of the present invention, Figure 3 , Figure 4 , Figure 5 In the example shown in FIG. 1 , the opening 23 is formed in a vertical direction instead of in the same direction. In the example shown in this figure, the opening 23 is formed on the side of the microfluidic chip 3. The advantages of this arrangement are that molding becomes easy, the area during bonding can be further reduced, and the bonding strength can be improved.

[0055] In addition, although not limited to this, it is preferred to perform a pretreatment process before joining the first substrate 1 and the second substrate 2. The pretreatment process is a treatment process for facilitating the joining of substrates to each other. As a specific example, it is preferred to perform surface modification on the first joining surface 11 and the second joining surface 21 of each substrate to make it hydrophilic. In addition, as a modification method, vacuum plasma treatment or atmospheric pressure plasma treatment can be used. In addition, as a treatment for surface modification of the joining surfaces of the two substrates, in addition to plasma treatment, vacuum ultraviolet (VUV) treatment in which vacuum ultraviolet (VUV) is irradiated to the joining surfaces from an excimer lamp, corona discharge treatment, etc. can also be used. Since the fine flow channel portion may be deformed due to heat, it is preferred to select vacuum plasma treatment or vacuum ultraviolet (VUV) that suppresses heat generation, but in terms of the production process under atmospheric pressure, vacuum ultraviolet (VUV) treatment is more preferred.

[0056] In addition, each substrate after the pre-treatment is preferably joined to the bonding surface by a hot pressing process. The glass transition temperature is heated to the upper limit, so that it can be effectively joined by pressurizing from both sides. Because the higher the heat resistance of the resin is, the thicker the substrate is, the longer the time for heat transfer to the bonding surface is, so the heating time is preferably appropriately regulated between a few seconds to a few minutes. According to the required bonding strength, it is also possible to join at room temperature. Although it is possible to join under the pressure of about a few kgf, it is necessary to increase the pressure according to the size of the microfluidic chip 3 joined and the bubbles present on the bonding surface. After the pre-treatment of the joint, the hot pressing process should be carried out quickly within a few minutes, but it is also possible to carry out hot pressing bonding every few days.

[0057] Since the above-mentioned joining method does not use an adhesive or bonding agent, the joining can be performed without blocking or closing the cross-section of the micro-channel groove. At this time, there is no adhesive layer or bonding layer between the first joining surface 11 and the second joining surface 21. In addition, it goes without saying that the microfluidic chip 3 stacked with more than three substrates can also be joined in a similar manner. In addition, by having a recess 13 and an opening 23, the area of ​​the pressurized joining surface can be reduced, and as a result, the joining can be performed with a small pressing force, thereby reducing the deformation of the channel groove 12 and the like.

[0058] Furthermore, even if the outer surface of the microfluidic chip 3 according to the present embodiment is coated, evaporated, or sputtered with a protective layer or covered with a sticker, film, ink, or other coating material as needed, there is no problem as long as the characteristics of the liquid injection and discharge part, the optical observation part, and the opening part are maintained, which allows for greater freedom in product design.

[0059] like Figure 6As shown, in the configuration of the present invention, in the event that liquid leaks from the injection port 22 and the discharge port 22 during use, the liquid can be stored in the recess 13 from the opening 23. Alternatively, the recess 13 can be used as a receiving vessel to store liquid leaked from the joint boundary surface 31 due to unexpected hydraulic pressure, thereby having the function of preventing liquid from leaking to the outside of the microfluidic chip 3. In addition, the liquid leaked due to the presence of the opening 23 does not cause the pressure in the recess 13 to increase, thereby preventing further peeling of the joint boundary surface 31 and preventing unnecessary liquid from leaking to the surface layer of the microfluidic chip 3 again.

[0060] like Figure 7 As shown, in the microfluidic chip 3 according to the present embodiment, from the viewpoint of performing multiple processes, it is preferred to independently form a plurality of flow channels 12 in one substrate, but in the case where a plurality of independent flow channels 12 are formed, it is preferred that the recess 13 is disposed between the plurality of independent flow channels 12. With such an arrangement, even if liquid fills one flow channel 12 and an accident such as insufficient close bonding between the substrates occurs, the liquid will flow into the recess 13, thereby reducing the risk of liquid leaking into another flow channel 12.

[0061] In addition, in the microfluidic chip 3 according to the present embodiment, it is preferred that the area of ​​the opening 23 is smaller than the area of ​​the recess 13 when observed from the Z direction (upper and lower surface sides) of the chip surface. From another perspective, it is preferred that the area of ​​the recess 13 is larger than the area of ​​the opening 23 when observed from the Z direction of the surface of the microfluidic chip 3. In this case, the bonding surface of the second substrate 2 covers the recess 13 and becomes a burr surface 15, thereby achieving a structure in which the accumulated liquid is difficult to return to the surface. In addition, there can be multiple openings 23 for one recess 13. In addition, as long as it can perform its function, the shape can be arbitrarily designed. In the case of multiple openings 23, it is also preferred that the bonding surface covers the recess 13. In addition, the cross-sectional shape of the recess 13 can also be a shape with steps.

[0062] In addition, the bottom of the recess 13 is preferably the same depth as or lower than the depth of the flow channel 12. By such a configuration, the volume of the recess 13 can be larger than the entire volume of the flow channel 12, thereby providing a margin for the stored liquid.

[0063] In addition, when a plurality of recesses 13 are formed, these recesses 13 may be connected to each other through grooves that are not connected to the flow channel groove 12, or may be arranged to surround the flow channel groove 12. Figure 6 Since the liquid flows in in directions other than the direction of the arrow in FIG. 1 , it is preferable to appropriately form the opening 23 and the recess 13 according to the design of the flow channel groove 12 .

[0064] In the microfluidic chip 3, the substrate has light transmittance. Here, "light transmittance" refers to the property of transmitting at least a portion of the incident light. Although not limited to this, specifically, the transmittance of light (633nm) of the flat portion and the fine concave-convex portion of the substrate is preferably 10% or more and 60% or less, and more preferably 20% or more and 50% or less. If the transmittance is less than 10%, the detection light will not be transmitted, so it is not preferred.

[0065] In addition, if Figure 8 It is explained that an appropriate gradient can be set on the concave side 14 of the concave portion 13 of the first substrate 1. In the production process, when the molded product is made of resin, it is not only easy to demold from the mold, but also the detection light generated in the flow channel groove 12 is refracted and totally reflected by the concave side 14, so that the unnecessary light 4 is difficult to return to the flow channel groove side, thereby having the effect of reducing optical noise.

[0066] In addition, when a gradient is set on the recess side 14 of the recess 13, there is a disadvantage that the light transmittance is reduced when the substrate is colored and transparent, but it has the effect of absorbing scattered light and reducing noise light, so the optical path length and the thickness of the molded product can be appropriately designed.

[0067] Furthermore, the material of the plate-shaped portion of the first substrate 1 and the second substrate 2 may be made of a resin that transmits only light in a specific wavelength range such as ultraviolet rays and infrared rays, thereby eliminating the need for components such as filters disposed on the detection device side.

[0068] In addition, if Fig. 9 As shown in the cross-sectional schematic diagram, the height of the opening 23 is set to be lower than the height of the corner of the injection port 22 and the discharge port 22 in the gravity direction (-Z side direction), so that the leaked liquid can be easily guided to the recessed portion 13 through the height difference 33 between the edge 24 of the opening and the edge of the injection port 22 and the discharge port 22.

[0069] The corner recess 25 of the opening 23 is set to have a flow channel shape or a shape surrounding the injection port 22 and the discharge port 22 when viewed from the Z direction, and is designed to guide the leaked liquid 32 to the opening 23, thereby improving the function. That is, the "corner recess" refers to a recess formed on at least one of the first substrate and the second substrate, which is used to connect multiple openings.

[0070] In addition, if Fig.10As shown in the cross-sectional schematic diagram, in the hot pressing bonding process, according to the configuration positions of the opening 23 and the injection port 22 and the discharge port 22, a through hole 53 for degassing is provided on the hot pressing mold 5 used for pressurization, so that the bubbles remaining on the bonding surface can be removed like the degassing gas flow 51, thereby improving the bonding strength. In addition, during hot pressing, according to the area of ​​the recess 13, the edge height of the opening 23 can be twisted to be formed at a position lower than the edge height of the injection port 22 and the discharge port 22. When producing the second substrate 2, the corner recess 25 larger than the edge 24 of the opening is pre-set, which also makes it easy to align the hole positions of the second substrate 2 and the hot pressing mold 5.

[0071] In addition, if Fig.11 As shown in the cross-sectional schematic diagram of , the closer the optical measurement observation surface 26 formed on the second substrate 2 is to the first substrate 1 (the thinner the second substrate is), the easier it is to observe the flow channel 12. In addition, this has the advantage of shortening the optical path length through the substrate, thereby improving the S / N ratio and suppressing autofluorescence.

[0072] In addition, since the hot pressing mold 5 does not contact the optical measurement observation surface 26 during the hot pressing process, scratches on the observation surface can be prevented. In addition, during processing, transportation and use, the microchannel chips can be stacked on each other to prevent scratches when placed.

[0073] As described above, in the microfluidic chip according to this embodiment, by applying a unique design, liquid leakage during use can be received, and in addition to being used as a medical microfluidic chip, it can also be used as a molded product that reduces optical noise, such as a chip for a chemical analysis device.

[0074] Example

[0075] First, a resist pattern of the concave and convex parts of the flow channel is formed by photolithography. In order to be mounted on a mold produced by injection molding, a fine concave and convex pattern is transferred from the resist pattern by electroforming to make a nickel mold. The nickel mold is mounted on the mold, and the pattern is transferred to the resin by injection molding.

[0076] As the specification of the produced molded product, a plurality of flow channels having a pair of flat surfaces, a depth of 400 μm and a thickness of 1 mm were formed.

[0077] For resin materials such as acrylic, polystyrene, polycarbonate, cycloolefin polymer and COC, it has been confirmed that thermocompression bonding can be achieved without the use of adhesives.

[0078] When a molded product having an opening and a molded product without an opening were observed and compared during the bonding process, it was confirmed that the opening had a degassing effect.

[0079] As described above, it has been confirmed that the effects of the present invention can be fully achieved in actual resin molded products.

[0080] Industrial Applicability

[0081] The present invention has industrial applicability as a microfluidic chip and a method for manufacturing the same, and is particularly applicable to a microfluidic chip in which substrates are stacked and integrally bonded to form a microfluidic channel between the bonding surfaces and a method for manufacturing the same.

[0082] (Explanation of Reference Numerals)

[0083] 1: First substrate

[0084] 2: Second substrate

[0085] 3: Microfluidic chip

[0086] 4: Unwanted Light

[0087] 5: Hot pressing mold

[0088] 11: First joint surface

[0089] 12: Runner groove

[0090] 13: concave part

[0091] 14: Side of concave part

[0092] 15: Burr surface

[0093] 21: Second joint surface

[0094] 22: Inlet / outlet

[0095] 23: Opening

[0096] 24: The edge of the opening

[0097] 25: Mouth and mouth recesses

[0098] 26: Optical measurement observation surface

[0099] 31: Bonding boundary surface

[0100] 32: Leakage

[0101] 33: The height difference of the edge

[0102] 51: Degassing

[0103] 53: Through hole.

Claims

1. A microfluidic chip, characterized in that: The microfluidic chip is formed in a light-transmitting plate shape and has a flow channel groove sealed inside except for an injection port and an outlet. The microfluidic chip comprises a first substrate and a second substrate. The first substrate is formed with the flow channel groove, has a first bonding surface for being stacked and integrally bonded with the second substrate, and has a recessed portion that is not connected to the flow channel groove. The second substrate has a second bonding surface for being stacked and integrally bonded with the first substrate, and is formed with at least one of the injection port communicating with the flow channel groove or the discharge port communicating with the flow channel groove, An opening portion connected to the recessed portion is formed in at least one of the first substrate and the second substrate.

2. The microfluidic chip according to claim 1, characterized in that: The opening portion is formed in the second substrate in the same direction as the recessed portion.

3. The microfluidic chip according to claim 1, characterized in that: The opening is formed on a side surface of at least one of the first substrate and the second substrate.

4. The microfluidic chip according to claim 1, characterized in that: The area of ​​the recessed portion is larger than the area of ​​the opening portion.

5. The microfluidic chip according to claim 1, characterized in that: A gradient is formed on at least a portion of the side surface of the recess.

6. The microfluidic chip according to claim 1, characterized in that: The depth of the recessed portion from the first joint surface is deeper than the depth of the flow channel groove.

7. The microfluidic chip according to any one of claims 1 to 6, characterized in that: The edge of the opening is formed to be lower than the edge height of one of the injection port or the discharge port, the height difference of the edge is 0.1 μm or more, and a corner recess thinner than the thickness of the second substrate is formed.

8. The microfluidic chip according to claim 7, characterized in that: A plurality of the openings are formed, and the corner recess communicates with the plurality of the openings.

9. The microfluidic chip according to any one of claims 1 to 6, characterized in that: There is no adhesive layer or bonding layer on the first joint surface and the second joint surface.

10. The microfluidic chip according to any one of claims 1 to 6, characterized in that: A plurality of the flow channel grooves are independently arranged, and the recessed portion is arranged between the flow channel grooves.

11. The microfluidic chip according to any one of claims 1 to 6, characterized in that: An optical measurement observation surface is formed on the second substrate, and the second substrate is located above the flow channel formed on the first substrate.

12. A method for manufacturing a microfluidic chip, characterized in that: The microfluidic chip is formed in a light-transmitting plate shape and has a flow channel groove sealed inside except for an injection port and an outlet. The microfluidic chip comprises a first substrate and a second substrate. The first substrate is formed with the flow channel groove, has a first bonding surface for being stacked and integrally bonded with the second substrate, and has a recessed portion that is not connected to the flow channel groove. The second substrate has a second bonding surface for being stacked and integrally bonded with the first substrate, and is formed with at least one of the injection port communicating with the flow channel groove or the discharge port communicating with the flow channel groove, An opening portion connected to the recessed portion is formed in at least one of the first substrate and the second substrate.

Images