JP7722012B2 - Microchannel chip and method for manufacturing the same - Google Patents

Description

This disclosure relates to a microchannel chip and a method for manufacturing the same.

In recent years, technologies have been proposed that use lithography and thick-film processing techniques to form microscopic reaction fields, enabling testing in the range of a few μL to a few nL. This technology, which utilizes such microscopic reaction fields, is called μ-TAS (Micro Total Analysis System).

μ-TAS is applied in areas such as genetic testing, chromosome testing, cell testing, and pharmaceutical development, as well as biotechnology, testing for trace substances in the environment, investigating the rearing environment of agricultural crops, and genetic testing of agricultural crops. The introduction of μ-TAS technology can bring about significant benefits, including automation, increased speed, high accuracy, low cost, rapidity, and reduced environmental impact.

μ-TAS often uses micrometer-sized flow paths (microflow paths, microchannels) formed on a substrate, and such substrates are called chips, microchips, microflow path chips, etc.

Traditionally, these microchannel chips have been fabricated using techniques such as injection molding, molding, cutting, and etching. Furthermore, glass substrates are primarily used as the substrate for microchannel chips because they are easy to manufacture and allow for optical detection. Meanwhile, development is also underway for microchannel chips made from inexpensive resin materials, which are lightweight, less prone to breakage than glass substrates, and less expensive. One method for manufacturing microchannel chips using resin materials involves forming a resin pattern for the channel using photolithography, and then bonding a lid material to the resin to create the microchannel chip. This method makes it possible to form fine channel patterns, which was difficult to achieve with conventional technology.

Methods for bonding substrates of microchannel chips include thermocompression bonding using a heat press or ultrasonic welder (e.g., Patent Document 1), and bonding using adhesives (e.g., Patent Document 2). In addition to these, a method has been proposed in which a process gas is converted into plasma at or near atmospheric pressure to modify the substrate surface and bond the substrates without using adhesives (e.g., Patent Document 3).

Japanese Patent Application Laid-Open No. 2002-139419 Japanese Patent Application Laid-Open No. 2003-60127 JP 2011-104886 A

In manufacturing a microchannel chip, the hardness of the resin layer that forms the channel is important when joining the resin layer to the cover material.
For example, if the resin layer is too hard, when there is a slight difference in level between the resin layer and the lid, the resin layer cannot elastically deform to conform to the contact surface of the lid, which may reduce adhesion and cause a gap.On the other hand, if the resin layer forming the flow path is too soft, the flow path may be significantly deformed when the resin layer and the lid are bonded together, and for example, the height of the flow path may change, causing a small gap between the joint surfaces of the resin layer and the lid.
When poor bonding occurs, such as when a gap forms between the resin layer and the lid material, problems such as fluid leakage from the gap occur. Furthermore, such poor bonding significantly reduces product yield. Therefore, in microchannel chips, there is a need to improve the bonding between the resin layer that forms the channel and the lid material, i.e., to prevent the occurrence of poor bonding.

Furthermore, if the resin layer forming the flow channel is too soft, the resin layer may deform significantly, causing deformation of the fine flow channel itself, resulting in the channel being crushed and blocked. In this case, when used for testing with μ-TAS, reactions may not proceed properly in the microchannel chip, and the expected performance may not be achieved. Therefore, there is a demand for microchannel chips that can suppress deformation (including blockage) of the flow channel and provide the expected performance.

In view of the above-mentioned problems, the present disclosure aims to provide a microchannel chip that can suppress the occurrence of poor bonding between the resin layer that forms the channel and the lid material, as well as deformation of the channel, and a method for manufacturing the same.

In order to solve the above problems, a microchannel chip according to one aspect of the present disclosure includes a substrate, a partition layer made of a resin material and provided on the substrate to form a channel, and a cover layer provided on a surface of the partition layer opposite to the substrate, wherein the elastic modulus of the partition layer is within a range of 1 MPa or more and 10 GPa or less.
Furthermore, a microchannel chip according to another aspect of the present disclosure includes a substrate, a partition layer made of a resin material and provided on the substrate to form a channel, and a cover layer provided on the surface of the partition layer opposite to the substrate, wherein the elastic modulus of the partition layer is within a range of more than 2 GPa and not more than 10 GPa.
Furthermore, a micro-channel chip according to still another aspect of the present disclosure includes a substrate, a partition layer made of a resin material and provided on the substrate to form a channel, and a cover layer provided on the surface of the partition layer opposite to the substrate, wherein the partition layer has an elastic modulus of 1 MPa or more and 2 GPa or less, and a Vickers hardness of 2 HV or more.

A method for manufacturing a micro-channel chip according to an aspect of the present disclosure includes the steps of: applying a resin onto a substrate; exposing the applied resin to light; developing and washing the exposed resin to form a partition layer on the substrate that defines a channel; post-baking the partition layer; and bonding a cover layer to a surface of the partition layer opposite to the substrate.
The elastic modulus of the partition wall layer is set to be in the range of 1 MPa to 10 GPa.

According to an aspect of the present disclosure, a microchannel chip can be provided that can suppress the occurrence of poor bonding between the resin layer that forms the channel and the lid material, as well as deformation of the channel.

1A and 1B are schematic diagrams showing an example of a configuration of a micro-channel chip according to a first embodiment of the present disclosure, in which FIG. 1A is a schematic plan view showing the example of a configuration of a micro-channel chip according to a first embodiment of the present disclosure, and FIG. 1B is a schematic cross-sectional view showing the example of a configuration of a micro-channel chip according to a first embodiment of the present disclosure. 1 is a flowchart showing an example of a method for manufacturing a micro-channel chip according to a first embodiment of the present disclosure. FIG. 2 is a cross-sectional view schematically illustrating a configuration example of a micro-channel chip according to a second embodiment of the present disclosure. FIG. 10 is a cross-sectional view schematically illustrating a configuration example of a micro-channel chip according to a third embodiment of the present disclosure.

The present disclosure will be explained below through embodiments, but the following embodiments do not limit the invention as claimed. Furthermore, not all combinations of features described in the embodiments are necessarily essential to the solution of the invention. Furthermore, the drawings are a schematic representation of the invention as claimed, and the dimensions of the width, thickness, etc. of each part differ from the actual dimensions, and the ratios between these dimensions also differ from the actual dimensions.

A micro-channel chip according to a first embodiment of the present disclosure will now be described. Note that in the following description, the substrate side of the micro-channel chip may be referred to as "bottom" and the side opposite the substrate side of the micro-channel chip (the lid side) as "top."

As a result of extensive research, the present inventors have found that by controlling the elastic modulus and Vickers hardness of the resin layer that forms the channel in a microchannel chip, the resin layer that forms the channel can conform to slight steps such as variations in resin height when the resin layer is formed and surface irregularities and insufficient flatness of the lid material when bonding the resin layer that forms the channel to the lid material, thereby making it possible to suppress bonding defects such as the occurrence of gaps and deformation of the fine channel.As a result, the present inventors have invented a microchannel chip and a method for manufacturing the same that can suppress bonding defects between the resin layer that forms the channel and the lid material and deformation of the channel.
Hereinafter, each aspect of each embodiment of the present disclosure will be described with reference to the drawings.

1. First Embodiment (1.1) Basic Configuration of Micro-Channel Chip Fig. 1 is a schematic diagram illustrating one configuration example of a micro-channel chip 1 according to a first embodiment of the present disclosure (hereinafter referred to as "this embodiment"). Specifically, Fig. 1(a) is a schematic plan view of the micro-channel chip 1 of this embodiment. Fig. 1(b) is a schematic cross-sectional view showing a cross section of the micro-channel chip 1 taken along line A-A shown in Fig. 1(a).

1(a), the micro-channel chip 1 includes an input section 2 for introducing a fluid (e.g., a liquid), a channel section 3 through which the fluid introduced from the input section 2 flows, and an output section 4 for discharging the fluid from the channel section 3. In the micro-channel chip 1, the channel section 3 is covered with a cover layer 12, and the input section 2 and the output section 4 are through-holes provided in the cover layer 12. Details of the cover layer 12 will be described later.
FIG. 1( a ) shows the flow path portion 3 visible through a transparent cover layer 12 .

The microchannel chip 1 may have at least one input section 2 and one output section 4, and may have multiple of each. The microchannel chip 1 may also have multiple channel sections 3, and may be designed to allow for the joining and separation of fluids introduced from the input section 2.

Here, the components constituting the channel section 3 in the microchannel chip 1 will be described in detail. As shown in FIG. 1(b), the microchannel chip 1 includes a substrate 10, a partition layer 11 provided on the substrate 10 to form a channel, and a cover layer 12 provided on the surface of the partition layer 11 opposite the substrate 10. The channel section 3, through which fluid introduced from the input section 2 flows, is an area surrounded by the substrate 10, the partition layer 11, and the cover layer 12. The channel section 3 is defined by the partition layer 11 provided on the substrate 19, and the side opposite the substrate 10 is covered by the cover layer 12, which serves as a lid material. As described above, fluid is introduced into the channel section 3 from the input section 2 (see FIG. 1(a)) provided on the cover layer 12, and the fluid that has flowed through the channel section 3 is discharged from the output section 4.

(1.1.1) Substrate The substrate 10 is a base member of the micro-channel chip 1, and the channel section 3 is formed by a partition layer 11 provided on the substrate 10. In other words, the substrate 10 and the partition layer 11 can be said to be the main body of the micro-channel chip 1.
The substrate 10 can be formed from either a light-transmitting material or a light-non-transmitting material. For example, when the state (fluid state) inside the flow channel portion 3 is detected or observed using light, a material that is highly transparent to the light can be used. Examples of the light-transmitting material include resin and glass. Resins used as the light-transmitting material for forming the substrate 10 include acrylic resin, methacrylic resin, polypropylene, polycarbonate resin, cycloolefin resin, polystyrene resin, polyester resin, urethane resin, silicone resin, and fluorine-based resin, from the viewpoint of suitability for forming the main body portion of the micro-channel chip 1.

Furthermore, for example, if there is no need to detect or observe the state (fluid state) within the flow path section 3 using light, a non-light-transmitting material may be used. Examples of non-light-transmitting materials include silicon wafers and copper plates. The thickness of the substrate 10 is not particularly limited, but since a certain degree of rigidity is required in the flow path formation process, it is preferably in the range of 10 μm (0.01 mm) to 10 mm.

(1.1.2) Partition Layer The partition layer 11 is provided on the substrate and forms the flow path portion 3. The partition layer 11 can be made of a resin material. For example, a photosensitive resin can be used as the resin material for the partition layer 11.

The photosensitive resin forming the partition layer 11 is preferably photosensitive to light with a wavelength of 190 nm or more and 400 nm or less, which is in the ultraviolet light region. Photoresists such as liquid resists or dry film resists can be used as the photosensitive resin. These photosensitive resins may be either positive-type, in which the photosensitive region dissolves, or negative-type, in which the photosensitive region is insolubilized. Examples of photosensitive resin compositions suitable for forming the partition layer 11 in the microchannel chip 1 include radical negative-type photosensitive resins containing an alkali-soluble polymer, an addition-polymerizable monomer, and a photopolymerization initiator. Examples of photosensitive resin materials include acrylic resins, acrylic urethane resins (urethane acrylate resins), epoxy resins, polyamide resins, polyimide resins, polyurethane resins, polyester resins, polyether resins, polyolefin resins, polycarbonate resins, polystyrene resins, norbornene resins, phenol novolac resins, and other photosensitive resins, which can be used alone, in combination, or copolymerized.
In this embodiment, the resin material of the partition layer 11 is not limited to photosensitive resin, and may be, for example, silicone rubber (PDMS: polydimethylsiloxane) or a synthetic resin. Examples of synthetic resins that can be used include polymethyl methacrylate resin (PMMA), polycarbonate (PC), polystyrene resin (PS), polypropylene (PP), cycloolefin polymer (COP), and cycloolefin copolymer (COC). It is desirable to select the resin material of the partition layer 11 appropriately depending on the application.
Furthermore, the thickness of the partition layer 11 on the substrate 10, i.e., the height of the flow path section 3, is not particularly limited, but the height of the flow path section 3 needs to be greater than the height of the substance to be analyzed or inspected (e.g., drugs, bacteria, cells, red blood cells, white blood cells, etc.) contained in the fluid introduced into the flow path section 3. For this reason, the thickness of the partition layer 11, i.e., the height of the flow path section 3, is preferably within a range of 5 μm to 100 μm.
Similarly, since the width of the flow path portion 3 needs to be larger than the substance to be analyzed or inspected, the width of the flow path portion 3 defined by the partition layer 11 is preferably within the range of 5 μm to 100 μm.

In the micro-channel chip 1 according to this embodiment, the partition layer 11 has an elastic modulus in the range of 1 MPa to 10 GPa. A slight step may occur between the partition layer 11 and the cover layer 12 (lid material) made of a resin material when they are joined together during the manufacturing process of the micro-channel chip 1. If the elastic modulus of the partition layer exceeds 10 GPa, the partition layer 11 becomes excessively hard and is unable to conform to the slight step, which may result in a gap when the partition layer 11 is joined to the cover layer 12. In this case, poor joining may occur when the partition layer 11 and the cover layer 12 are joined together.
On the other hand, if the elastic modulus is less than 1 MPa, the partition layer 11 becomes excessively soft and is likely to deform during bonding in the manufacturing process of the micro-channel chip 1. In this case, deformation and blockage of the channel section 3 may occur.

In the micro-channel chip 1 according to this embodiment, the elastic modulus of the partition layer 11 is set to 10 GPa or less, thereby preventing the partition layer 11 from becoming excessively hard. Therefore, for example, when bonding the partition layer 11 to the cover layer 12, the partition layer 11 can conform to slight steps, preventing gaps and the like, and thus preventing poor bonding between the partition layer 11 and the cover layer 12.
Furthermore, by setting the elastic modulus of the partition layer 11 to 1 MPa or more, the micro-channel chip 1 can prevent the partition layer 11 from becoming excessively soft. This prevents the partition layer 11 from being significantly deformed by, for example, an external force applied when bonding the partition layer 11 to the cover layer 12, and prevents deformation and blockage of the channel portion 3.
In this way, in the microchannel chip 1 according to this embodiment, by setting the elastic modulus of the partition layer 11 within the range of 1 MPa or more and 10 GPa or less, it is possible to suppress the occurrence of poor bonding between the partition layer 11, which is a resin layer forming the channel, and the cover layer 12, which is a lid material, and deformation (including blockage) of the channel portion 3 formed by the partition layer 11.

Furthermore, in the microchannel chip 1 according to this embodiment, if the elastic modulus is set within the range of 1 MPa or more and 2 GPa or less, this is preferable because it can suppress the occurrence of poor bonding between the partition layer 11 and the cover layer 12, which is the lid material, and deformation (including blockage) of the channel section 3 formed by the partition layer 11, and it can also follow local unevenness on the bonding surfaces of the partition layer 11 and the cover layer 12.
Furthermore, in the microchannel chip 1 according to this embodiment, if the modulus of elasticity is in the range of more than 2 GPa and not more than 10 GPa, it is possible to suppress the occurrence of poor bonding between the partition layer 11 and the cover layer 12, which is the lid material, and deformation (including blockage) of the channel portion 3 formed by the partition layer 11. In addition, it is preferable because it is possible to follow large irregularities such as undulations on the bonding surfaces of the partition layer 11 and the cover layer 12 and warping of the substrate itself.
The control and measurement of the elastic modulus of the partition layer 11 in the micro-channel chip 1 will be described later.

As such, it is important for the partition layer 11 to have sufficient flexibility (elastic modulus) to conform to steps and other irregularities when bonded to the cover layer 12 and to prevent deformation or blockage of the flow path portion 3 due to external forces applied during bonding. On the other hand, it is also important for the partition layer 11 to be able to recover from deformation caused by external forces, for example, when the external force is removed after bonding to the cover layer 12, i.e., to be resistant to plastic deformation.

The inventors have found that plastic deformation is less likely to occur during bonding of the micro-channel chip 1 by setting the Vickers hardness of the partition layer 11 made of a resin material to a predetermined value or higher. Specifically, in the micro-channel chip 1 according to this embodiment, the partition layer 11 preferably has a Vickers hardness of 2 HV or higher. If the Vickers hardness is less than 2 HV, plastic deformation is more likely to occur, and deformation due to external force is less likely to return to its original state. If the Vickers hardness of the partition layer 11 is 2 HV or higher, plastic deformation of the partition layer 11 is less likely to occur, thereby more reliably suppressing deformation and blockage of the channel portion 3. Furthermore, the Vickers hardness of the partition layer 11 is preferably 80 HV or lower. If the Vickers hardness exceeds 80 HV, cracks, fissures, etc. may occur depending on the press pressure applied when bonding the partition layer 11 and the cover layer 12. By making the Vickers hardness 80 HV or less, it is possible to suppress the occurrence of cracks and fissures due to the pressing pressure when the partition layer 11 and the cover layer 12 are joined together.
The control and measurement of the Vickers hardness of the partition layer 11 in the micro-channel chip 1 will be described later.

(1.1.3) Cover Layer In the micro-channel chip 1 according to this embodiment, the cover layer 12 is a lid material that covers the channel section 3 as shown in FIG. 1(b). As described above, the cover layer 12 is provided on the surface of the partition layer 11 opposite the substrate 10, and faces the substrate 10 across the partition layer 11. More specifically, as shown in FIG. 1(b), in a cross-sectional view, the side edges of the cover layer 12 are supported by the partition layer 11, and the central region faces the substrate 10, and the central region defines the upper part of the channel section 3.

The cover layer 12 can be formed from either a light-transmitting or non-light-transmitting material. For example, when detecting or observing the state inside the channel using light, a material that is highly transparent to the light can be used. Examples of light-transmitting materials include resin and glass. Resins suitable for forming the cover layer 12 include acrylic resin, methacrylic resin, polypropylene, polycarbonate resin, cycloolefin resin, polystyrene resin, polyester resin, urethane resin, silicone resin, and fluorine-based resin, among others, because they are suitable for forming the main body of the microchannel chip 1. The thickness of the cover layer 12 is not particularly limited, but considering that through-holes corresponding to the input section 2 and output section 4 are provided in the cover layer 12, a thickness of 10 μm or more and 10 mm or less is preferred. Furthermore, it is desirable to pre-open holes corresponding to the input section 2 for introducing fluid (liquid) and the output section 4 for discharging fluid in the cover layer 12 before bonding it to the partition layer 11.

The elastic modulus of the cover layer 12 may be greater than the elastic modulus of the partition wall layer 11. In this case, the cover layer 12 has improved mechanical strength compared to the partition wall layer 11, and the durability against external forces applied when bonding to the partition wall layer 11 is improved.
The elastic modulus of the cover layer 12 may be smaller than that of the partition wall layer 11. In this case, the cover layer 12 is softer than the partition wall layer 11, which improves the conformability of the cover layer 12 at the joint surface between the partition wall layer 11 and the cover layer 12, thereby further suppressing poor joints. Furthermore, when the elastic modulus of the cover layer 12 is smaller than that of the partition wall layer 11, it becomes easier to drill holes corresponding to the input section 2 and the output section 4, which reduces the workload during manufacturing.
In the micro-channel chip 1 according to this embodiment, the modulus of elasticity of the cover layer 12 may be in the range of 1 MPa to 10 GPa, similar to the modulus of elasticity of the partition layer 11 .

(1.2) Method for Manufacturing Micro-Channel Chip Next, a method for manufacturing the micro-channel chip 1 according to this embodiment will be described. Fig. 2 is a flowchart showing an example of a method for manufacturing the micro-channel chip 1 according to this embodiment.
Here, an example in which the partition wall layer 11 is formed from a photosensitive resin will be described.

(Step S1)
In the method for manufacturing the micro-channel chip 1 according to this embodiment, first, a step of applying a resin onto the substrate 10 is performed. This provides a resin layer for forming the partition layer 11 on the substrate 10. In the method for manufacturing the micro-channel chip 1 according to this embodiment, for example, a resin layer made of a photosensitive resin (photosensitive resin layer) is formed on the substrate 10.

The photosensitive resin layer is formed on the substrate 10, for example, by coating the substrate 10 with a photosensitive resin. Coating can be performed by, for example, spin coating, spray coating, bar coating, etc., with spin coating being preferred from the viewpoint of film thickness controllability. The photosensitive resin can be coated on the substrate 10 in various forms, such as liquid, solid, gel, or film. Of these, it is preferred to form the photosensitive resin layer using a liquid resist.
Furthermore, a resin (e.g., a photosensitive resin) may be applied onto the substrate 10 so that the thickness of the resin layer (e.g., a photosensitive resin layer), i.e., the thickness of the partition wall layer 11, is in the range of 5 μm to 100 μm.

(Step S2)
Once the photosensitive resin has been formed on the substrate 10, a heating process (pre-baking process) is then carried out to remove the solvent contained in the resin (e.g., photosensitive resin) coated on the substrate 10. Note that in the manufacturing method of the microchannel chip 1 according to this embodiment, the pre-baking process is not an essential process, and may be carried out at an appropriate temperature and time optimal for the characteristics of the resin. For example, if the resin layer on the substrate 10 is a photosensitive resin, the pre-baking temperature and time are appropriately set to optimal conditions depending on the characteristics of the photosensitive resin.

(Step S3)
Next, a step of exposing the resin (e.g., photosensitive resin) coated on the substrate 10 is carried out. Specifically, a flow path pattern is written on the photosensitive resin coated on the substrate 10 by exposure. Exposure can be carried out, for example, by an exposure device using ultraviolet light as a light source or a laser writing device. Among these, exposure using a proximity exposure device or a contact exposure device using ultraviolet light as a light source is preferred. In the case of a proximity exposure device, exposure is carried out through a photomask having the flow path pattern arrangement of the microchannel chip 1. The photomask may be a photomask having a light-shielding film with a two-layer structure of chromium and chromium oxide.
As described above, a photosensitive resin that is photosensitive to light having a wavelength of 190 nm or more and 400 nm or less, which is in the ultraviolet light region, is used for the partition layer 11. Therefore, in this step (exposure step), the photosensitive resin coated on the substrate 10 is exposed to light having a wavelength of 190 nm or more and 400 nm or less.

If the photosensitive resin coated on the substrate 10 is a positive resist, the exposed areas dissolve to form the flow path section 3, and the photosensitive resin remaining in the unexposed areas becomes the partition layer 11. Also, if the photosensitive resin coated on the substrate 10 is a negative resist, the photosensitive resin remaining in the exposed areas becomes the partition layer 11, and the unexposed areas dissolve to form the flow path section 3. In this way, the manufacturing method for the microchannel chip 1 according to this embodiment allows the partition layer 11 that constitutes the flow path section 3 to be formed on the substrate 10 using photolithography.

If a chemically amplified resist or the like is used to form the resin layer on the substrate 10, it is recommended to perform a post-exposure bake (PEB) after exposure to promote the catalytic reaction of the acid generated by exposure.

(Step S4)
Next, the exposed photosensitive resin is developed to form a flow path pattern.
Development is carried out by reacting the photosensitive resin with a developer in a developing device such as a spray, dip, or paddle type. Examples of the developer that can be used include aqueous sodium carbonate solution, tetramethylammonium hydroxide, potassium hydroxide, and organic solvents. The developer may be an optimum solution suited to the properties of the photosensitive resin, and is not limited to these. The concentration and development time can be adjusted to the optimum conditions suited to the properties of the photosensitive resin.

(Step S5)
Next, a process is performed in which the developer used for development is completely removed from the resin layer (photosensitive resin layer) on the substrate 10 by washing. Washing can be performed using a washing device such as a spray, shower, or immersion type. As the washing water, for example, pure water, isopropyl alcohol, or the like, may be appropriately used as the washing water that is most suitable for removing the developer used in the development process. After washing, the substrate is dried using a spin dryer, an IPA vapor dryer, natural drying, or the like.

(Step S6)
Next, a heat treatment (post-baking) is performed on the partition layer 11 that forms the flow path pattern, i.e., the flow path portion 3. This post-baking process removes moisture remaining during development and cleaning. The post-baking process is performed using, for example, a hot plate or an oven. If drying is insufficient in the cleaning process of step S5, moisture from the developer or cleaning may remain in the partition layer 11. Furthermore, solvent that was not removed in the pre-baking process may also remain in the partition layer 11. This can be removed by performing the post-baking process.

(Step S7)
After the post-baking process, a surface modification process is performed on the partition layer 11 and the cover layer 12 (lid material) before bonding to the partition layer 11. One example of the surface modification process is plasma treatment. Note that the surface modification process may be performed as needed, and is not an essential process in the manufacturing method of the micro-channel chip 1 according to this embodiment.

(Step S8)
Next, a step of bonding a cover layer 12 to the post-baked partition layer 11 is performed. In this step, as shown in Fig. 1(b), the cover layer 12 is bonded to the surface of the partition layer 11 opposite to the substrate 10. As a result, the flow channel portion 3 is covered with the cover layer 12, and the micro-channel chip 1 shown in Figs. 1(a) and 1(b) is formed.
As a method for bonding the substrates that have been subjected to the surface modification treatment in step S7, it is preferable to use thermocompression bonding using, for example, a heat press or a heat roll machine.
It is desirable to provide holes corresponding to the fluid input section 2 and output section 4 (see FIG. 1A ) in the cover layer 12 before bonding to the partition wall layer 11. This can prevent problems with dust and contamination from occurring compared to when the holes are provided after bonding to the partition wall layer 11.

The method for joining the partition wall layer 11 and the cover layer 12 is not limited to the thermocompression bonding described above, and a method using an adhesive or a method for joining the partition wall layer 11 and the cover layer 12 by surface modification treatment of the joining surfaces thereof without using an adhesive may also be employed.
When bonding is performed using an adhesive, the adhesive can be determined based on factors such as the affinity with the materials constituting the partition wall layer 11 and the cover layer 12. The adhesive is not particularly limited as long as it can bond the partition wall layer 11 and the cover layer 12. For example, the adhesive used in this embodiment may be an acrylic resin adhesive, a urethane resin adhesive, an epoxy resin adhesive, or the like.

Methods of bonding by surface modification treatment without using adhesive include plasma treatment, corona discharge treatment, and excimer laser treatment. In this case, the reactivity of the surface of the partition wall layer 11 is improved, and the optimum treatment method can be selected appropriately depending on the affinity and adhesive compatibility between the partition wall layer 11 and the cover layer 12. Note that when bonding by surface modification treatment, it is sufficient to carry out step S7 above up to bonding the partition wall layer 11 and the cover layer 12.

As described above, the method for manufacturing the microchannel chip 1 according to this embodiment includes the steps of applying resin to the substrate 10 (step S1 above), exposing the applied resin to light (step S3 above), developing and washing the exposed resin to form a partition layer 11 that constitutes the channel section 3 on the substrate 10 (steps 4 and S5 above), post-baking the partition layer 11 that constitutes the channel section 3 (step S6 above), and bonding a cover layer 12 to the surface of the partition layer 11 opposite the substrate 10 (step S8 above).

Here, an example has been described in which a photosensitive resin is applied to the substrate 10 and then photolithography is used to form the partition layer 11 that constitutes the flow path section 3, but the present disclosure is not limited to this. The resin used to form the resin layer that becomes the partition layer 11 on the substrate 10 may be, for example, silicone rubber (PDMS) or a synthetic resin (PMMA, PC, PS, PP, COP, COC, etc.). For example, when forming the partition layer 11 using silicone rubber, a mold for the flow path pattern may be formed using photolithography, and the mold for the flow path pattern may be transferred to the silicone rubber to form the flow path pattern (the partition layer 11 that constitutes the flow path section 3).

(1.3) Method for controlling the elastic modulus and Vickers hardness of the partition layer In this embodiment, when manufacturing the microchannel chip 1 by the above-described manufacturing method, the elastic modulus of the partition layer 11 is set to be in the range of 1 MPa or more and 10 GPa or less, and further, the Vickers hardness of the partition layer 11 is set to be 2 HV or more.

(1.3.1) Method for Controlling Elastic Modulus and Vickers Hardness by Post-Bake Treatment In this embodiment, the elastic modulus and Vickers hardness of the partition layer 11 can be controlled by the post-bake treatment (step S6 above) in the manufacturing method of the micro-channel chip 1. Specifically, the elastic modulus and Vickers hardness of the partition layer 11 are controlled by the temperature and time during the post-bake treatment. As described above, the original purpose of the post-bake treatment is to remove moisture from the developer and during cleaning (and in some cases, the solvent for the resin applied to the substrate 10). At this time, hardening of the partition layer 11 progresses as the moisture is removed. By controlling the progress of this hardening, the elastic modulus and Vickers hardness of the partition layer 11 can be controlled.
If the temperature during post-baking is too high or the post-baking time is too long, the curing of the barrier layer 11 may proceed more than necessary, resulting in excessive increases in the modulus of elasticity and Vickers hardness. Therefore, the optimum temperature for controlling the modulus of elasticity and Vickers hardness is preferably a temperature 30° C. to 50° C. lower than the glass transition temperature of the resin material forming the barrier layer 11. The post-baking time is preferably within 30 minutes, more preferably within 10 minutes. The post-baking time is preferably 5 minutes or longer.
In this way, by controlling the temperature and processing time during the post-baking process, it is possible to control the elastic modulus of the barrier layer 11 to be in the range of 1 MPa to 10 GPa, and further to control the Vickers hardness of the barrier layer to be 2 HV or more.

(1.3.2) Method for controlling elastic modulus and Vickers hardness by exposure In this embodiment, the elastic modulus and Vickers hardness of the partition layer 11 can also be controlled by the amount of exposure to ultraviolet light in the step of exposing the resin on the substrate 10 during the manufacture of the micro-channel chip 1. The above-mentioned exposure step (e.g., step S3) during the manufacture of the micro-channel chip 1 is originally performed for the purpose of forming the channel portion 3 (channel pattern) defined by the partition layer 11. However, for example, in the case of a radical polymerization type negative photosensitive resin, hardening of the photoexposed region progresses during exposure. By controlling the progress of this hardening, the elastic modulus and Vickers hardness of the partition layer 11 can be controlled.

It has been confirmed that an excessive exposure dose causes an excessive increase in the elastic modulus and Vickers hardness of the partition wall layer 11. Furthermore, an excessive exposure dose can result in problems such as a deterioration in pattern resolution, the generation of residues, or pattern dimensions that significantly deviate from the design values. On the other hand, an insufficient exposure dose can also result in problems such as pattern dimensions significantly deviating from the design values or the inability to form a flow path pattern. Therefore, in the exposure step (first exposure step) for forming the flow path pattern, an appropriate exposure dose for flow path pattern formation is first set. Here, the exposure dose is adjusted to control the elastic modulus and Vickers hardness of the resin applied to the substrate 10 within a range that does not cause problems in flow path pattern formation. Next, an exposure step (second exposure step) is performed to control the elastic modulus and Vickers hardness of the partition wall layer 11, which forms the flow path portion 3, in order to suppress the occurrence of poor bonding between the partition wall layer 11 and the cover layer 12 and the deformation of the flow path portion 3. The exposure dose in the second exposure step needs to be set appropriately depending on the resin material of the partition layer 11, but it is preferable that the exposure dose is greater than the exposure dose in the first exposure step for forming the flow path pattern and is within the range of 10 mJ/ ^cm2 or more and 1000 mJ/ ^cm2 or less.
Furthermore, the second exposure step may be performed on the flow path pattern before development following the first exposure step (as the processing of step S3 above), or may be performed on the flow path pattern after development before the post-bake processing (step S6 above).
In addition, a proximity exposure device, for example, can be used in the first exposure step and the second exposure step. In the second exposure step, the flow path pattern may also be exposed to light of the same wavelength (190 nm or more and 400 nm or less) as in step S3.

In this way, by performing the second exposure step as described above during the manufacture of the micro-channel chip 1 according to this embodiment, the elastic modulus of the partition layer 11 can be controlled to be within the range of 1 MPa to 10 GPa, and the Vickers hardness of the partition layer can be controlled to be 2 HV or more.
The elastic modulus of the partition wall layer 11 also varies depending on the resin material. For example, if the partition wall layer 11 is made of silicone rubber (PDMS), the elastic modulus is approximately 10 MPa and the Vickers hardness is approximately 0.1 HV. If the partition wall layer 11 is made of a photosensitive resin, the elastic modulus is in the range of 2 GPa to 10 GPa and the Vickers hardness is approximately 40 HV.

Thus, according to the present disclosure, by controlling the elastic modulus and Vickers hardness of the partition layer 11 in which the flow channel is formed using photolithography, it is possible to manufacture a micro-channel chip 1 that can conform to slight steps and can be bonded while suppressing deformation of the fine flow channel.
Specifically, by controlling the modulus of elasticity and Vickers hardness during the manufacture of micro-channel chip 1 as described above, it is possible to obtain micro-channel chip 1 that includes substrate 10, partition layer 11 made of a resin material and provided on substrate 10 to form channel portion 3, and cover layer 12 provided on the surface of partition layer 11 opposite substrate 10, wherein partition layer 11 has a modulus of elasticity in the range of 1 MPa to 10 GPa. This makes it possible to provide a micro-channel chip that can suppress the occurrence of poor bonding between the resin layer that forms the channel and the lid material and deformation of the channel.

(1.4) Method for Measuring Elastic Modulus and Vickers Hardness A microindentation tester is preferably used to measure the elastic modulus and Vickers hardness of the partition layer 11 and the cover layer 12. The microindentation tester performs a quasi-static indentation test on a sample to obtain the mechanical properties of the sample. The microindentation tester also analyzes the indentation depth when the maximum load is applied to the sample and the resulting curve to determine information such as hardness, elastic modulus, and power of plastic deformation and elastic deformation, and can analyze this information.
For example, a microindentation test is performed on a sample of the partition wall layer 11 using a square pyramidal indenter with a facing angle of 136° and an indentation load of 2 mN to measure the elastic modulus and Vickers hardness of the partition wall layer 11. The elastic modulus, which is the hardness in the elastic deformation region, is calculated from the slope of the curve when unloaded in the measurement results. The indentation is estimated from the indentation depth of the indenter, and the Vickers hardness, which is the hardness in the plastic deformation region, is calculated. The elastic modulus and Vickers hardness of the cover layer 12 can also be measured in a similar manner.

(1.5) Effects of First Embodiment The micro-channel chip 1 as described above has the following effects.
(1) The microchannel chip 1 according to this embodiment includes a substrate 10, a partition layer 11 made of a resin material and disposed on the substrate 10 to form a channel portion 3, and a cover layer 12 disposed on the surface of the partition layer 11 opposite the substrate 10, and the elastic modulus of the partition layer 11 is within a range of 1 MPa to 10 GPa.
This makes it possible to suppress the occurrence of poor bonding between the partition layer 11, which is a resin layer that forms the flow path portion 3, and the cover layer 12, which is a lid material, and to suppress deformation of the flow path portion 3.
(2) Furthermore, the microchannel chip 1 according to this embodiment includes a substrate 10, a partition layer 11 made of a resin material and provided on the substrate 10 to form a channel portion 3, and a cover layer 12 provided on the surface of the partition layer 11 opposite the substrate 10, and the elastic modulus of the partition layer 11 may be within a range of more than 2 GPa and not more than 10 GPa.
This makes it possible to suppress the occurrence of poor bonding between the partition layer 11, which is a resin layer that forms the flow path portion 3, and the cover layer 12, which is a lid material, and to suppress deformation of the flow path portion 3.
(3) Furthermore, the microchannel chip 1 according to this embodiment includes a substrate 10, a partition layer 11 made of a resin material and provided on the substrate 10 to form a channel portion 3, and a cover layer 12 provided on the surface of the partition layer 11 opposite to the substrate 10, wherein the elastic modulus of the partition layer 11 is within a range of 1 MPa or more and 2 GPa or less, and the Vickers hardness of the partition layer 11 may be 2 HV or more.
This makes it possible to suppress the occurrence of poor bonding between the partition layer 11, which is a resin layer that forms the flow path portion 3, and the cover layer 12, which is a lid material, and to suppress deformation of the flow path portion 3.

(4) In the micro-channel chip 1 according to this embodiment, the Vickers hardness of the partition layer is preferably 2 HV or more. This makes it difficult for plastic deformation to occur in the partition layer 11, thereby more reliably suppressing deformation and blockage of the channel portion 3.
(5) In the micro-channel chip 1 according to this embodiment, the cover layer 12 may have a higher elastic modulus than the partition layer 11 .
This makes the cover layer 12 more mechanically strong than the partition wall layer 11 , and improves durability against external forces applied when bonding to the partition wall layer 11 .
(6) In the micro-channel chip 1 according to this embodiment, the cover layer may have a lower modulus of elasticity than the partition layer.
This makes the cover layer 12 softer than the partition wall layer 11, improving the conformability of the cover layer 12 at the joint surface between the partition wall layer 11 and the cover layer 12, thereby further suppressing poor joints.

(7) In addition, in the microchannel chip 1 according to this embodiment, the resin material forming the partition layer 11 is preferably a photosensitive resin that is photosensitive to light in the ultraviolet region with a wavelength of 190 nm or more and 400 nm or less.
This allows the partition layer 11 that constitutes the flow path portion 3 to be formed on the substrate 10 by photolithography.

(8) The method for manufacturing the microchannel chip 1 according to this embodiment includes the steps of applying a resin onto the substrate 10, exposing the applied resin to light, developing and washing the exposed resin to form a partition layer 11 that defines the channel portion 3 on the substrate 10, post-baking the partition layer 11, and bonding a cover layer 12 to the surface of the partition layer 11 opposite the substrate, wherein the elastic modulus of the partition layer 11 is set to be in the range of 1 MPa to 10 GPa.
This makes it possible to provide a microchannel chip that can suppress the occurrence of poor bonding between the partition layer 11, which is a resin layer that forms the channel section 3, and the cover layer 12, which is a lid material, and can suppress deformation of the channel section 3.
(9) In the method for manufacturing the micro-channel chip 1 according to this embodiment, the Vickers hardness of the partition layer 11 is set to 2 HV or more.
This makes it possible to provide a micro-channel chip in which plastic deformation of the partition layer 11 is unlikely to occur and deformation and blockage of the channel section 3 can be more reliably suppressed.
(10) In the method for manufacturing the micro-channel chip 1 according to this embodiment, the elastic modulus and Vickers hardness of the partition layer 11 are controlled by post-baking.
This allows the modulus of elasticity and Vickers hardness to be controlled by photolithography.
(11) In the method for manufacturing the micro-channel chip 1 according to this embodiment, the elastic modulus and Vickers hardness of the partition layer 11 are controlled by the amount of ultraviolet light exposure in the step of exposing the resin.
This allows the modulus of elasticity and Vickers hardness to be controlled by photolithography.
(12) In the method for manufacturing the micro-channel chip 1 according to this embodiment, the photosensitive resin is exposed to light in the ultraviolet region with a wavelength of 190 nm or more and 400 nm or less in the step of exposing the resin.
This allows the partition layer 11 that constitutes the flow path portion 3 to be formed on the substrate 10 by photolithography.

2. Second Embodiment A micro-channel chip according to a second embodiment of the present disclosure will now be described with reference to Fig. 3. Fig. 3 is a cross-sectional view illustrating an example of the configuration of micro-channel chip 102 according to the second embodiment of the present disclosure.
Micro-channel chip 102 includes substrate 20, adhesion layer 24 disposed on substrate 20, partition layer 21 that forms channel section 23 on substrate 20, and cover layer 22. That is, micro-channel chip 102 differs from micro-channel chip 1 according to the first embodiment in that it includes adhesion layer 24 between the substrate and the partition layer.

The adhesion layer 24 will be described below. Note that the components other than the adhesion layer 24 (substrate 20, partition layer 21, cover layer 22, and flow channel section 23) are similar in configuration to the substrate 10, partition layer 11, cover layer 12, and flow channel section 3 of the micro-channel chip 1, and therefore will not be described here.

In order to improve adhesion between the substrate 10 and a resin layer (e.g., a photosensitive resin layer) in the microchannel chip 102, the substrate 20 may be subjected to a hydrophobic surface treatment (HMDS treatment) or coated with a thin film of resin. In particular, when glass is used for the substrate 10, a thin film adhesion layer 24 may be provided between the substrate 20 and the partition layer 21 (photosensitive resin layer) as shown in Figure 3. In this case, the fluid (e.g., liquid) flowing through the channel portion 23 comes into contact with the adhesion layer 24 rather than the substrate. Therefore, it is sufficient for the adhesion layer 24 to be resistant to the fluid introduced into the channel portion 23. Providing the adhesion layer 24 on the substrate 20 can also contribute to improving the resolution of the channel pattern made of photosensitive resin.

3. Third Embodiment A micro-channel chip according to a third embodiment of the present disclosure will now be described with reference to Fig. 4. Fig. 4 is a cross-sectional view illustrating an example configuration of micro-channel chip 103 according to the third embodiment of the present disclosure.
Micro-channel chip 103 includes substrate 30, partition layer 31 that forms channel section 33 on substrate 30, cover layer 32, and adhesion layer 34 provided between partition layer 31 and cover layer 32. That is, micro-channel chip 103 differs from micro-channel chip 1 according to the first embodiment in that it includes adhesion layer 34.

The adhesion layer 34 will be described below. Note that the components other than the adhesion layer 34 (substrate 30, partition layer 31, cover layer 32, and flow channel portion 33) are similar in configuration to the substrate 10, partition layer 11, cover layer 12, and flow channel portion 3 of the micro-channel chip 1, and therefore will not be described here.

When an adhesive is used to bond the partition layer and cover layer, as shown in Figure 4, an adhesive can be applied to the partition layer 31 to form an adhesion layer 34 between the partition layer 31 and the cover layer 32. In this case, the fluid (e.g., liquid) flowing through the flow path 33 comes into contact with the adhesion layer 34. Therefore, the adhesion layer 34 only needs to be resistant to the fluid introduced into the flow path 33. By providing the adhesion layer 34, the adhesion between the partition layer 31 and the cover layer 32 can be strengthened, improving the durability of the microchannel chip 103 itself.

<Example>
The microchannel chip according to the present disclosure will be described below using specific examples. It should be noted that the present disclosure is not limited to the following examples.

Example 1
First, a transparent photosensitive resin was applied to a glass substrate to form a photosensitive resin layer. PDMS was used as the photosensitive resin. The photosensitive resin was applied to the glass substrate using a spin coater at a rotation speed of 1100 rpm for 30 seconds. The rotation speed and time were adjusted to achieve a film thickness of 50 μm. Next, a heat treatment (pre-baking) was performed on a hot plate to remove residual solvent contained in the photosensitive resin. Pre-baking was performed at a temperature of 90°C for 20 minutes.

Next, the photosensitive resin layer on the glass substrate was exposed to light to write a flow path pattern. Specifically, the photosensitive resin was exposed to light through a photomask having a pattern arrangement of microflow paths. The photomask used had a two-layer structure of chromium and chromium oxide as a light-shielding film. A proximity exposure device was used for exposure. The exposure device used a high-pressure mercury lamp as a light source, and the exposure wavelength was a broadband including g-, h-, and i-rays. The exposure dose for exposure to form the flow path pattern (first exposure step) was "100 mJ/ ^cm2 ."

Next, the exposed photosensitive resin layer was developed to form a flow path pattern. Specifically, the photosensitive resin layer was developed for 60 seconds using an alkaline developer (TMAH 2.38%) to dissolve the unexposed portions and pattern the flow path structure.
Subsequently, the developing solution was removed from the photosensitive resin layer on the substrate by shower washing with ultrapure water, and the substrate was dried with a spin dryer.

Next, an exposure step (second exposure step) was carried out to control the elastic modulus and Vickers hardness. The exposure dose in the second exposure step was set to 50 mJ/ ^cm2 .

Next, the flow path pattern was post-baked in an oven at 100°C for 10 minutes. This resulted in the formation of a flow path portion (flow path pattern) defined by the partition wall layer. The minimum width of the opposing partition wall layers, i.e., the minimum width of the flow path, was 50 µm.
After post-baking, the elastic modulus and Vickers hardness of the barrier layer were measured. A microindentation tester (HM2000) was used for the measurements. Specifically, a square pyramidal indenter with a facing angle of 136° was used to measure the elastic modulus and Vickers hardness at an indentation load of 2 mN. The elastic modulus, which is the hardness in the elastic deformation region, was measured from the slope of the measurement result curve upon unloading, and the indentation was estimated from the indenter indentation depth to measure the Vickers hardness, which is the hardness in the plastic deformation region. The measured elastic modulus was 0.001 GPa (1 MPa). The measured Vickers hardness was 0.008 HV.

Next, a surface modification process was performed on the bonding surface between the partition layer of the flow path pattern and a separately prepared cover layer. The cover layer was made of PMMA with pre-punched holes for the inlets and outlets of the flow paths. Plasma treatment was used for the surface modification process. The plasma treatment conditions were a pressure of 10 Pa, an oxygen gas flow rate of 10 sccm, an RF power of 100 W, and a treatment time of 30 seconds.

Next, a heat press was used to bond the partition layer of the channel pattern to the cover layer. The heat press processing conditions were a temperature of 100°C, a press pressure of 5 kN, and a processing time of 30 seconds. This resulted in the production of a microchannel chip according to this example.

Example 2
A urethane acrylate resin was used as the photosensitive resin to be applied to the glass substrate. The exposure dose in the second exposure step using the proximity exposure device was ^set to 100 mJ/cm. Otherwise, the microchannel chip of this example was obtained in the same manner as in Example 1.
Furthermore, in the microchannel chip according to this example, after post-baking, the elastic modulus and Vickers hardness were measured in the same manner as in Example 1. In this example, the measured result of the elastic modulus was 0.25 GPa, and the measured result of the Vickers hardness was 2 HV.

Example 3
The photosensitive resin applied to the glass substrate was the same urethane acrylate resin as in Example 2. The exposure dose in the second exposure step using the proximity exposure device was 170 mJ/ ^cm2 , and the post-bake temperature was 120° C. Otherwise, the microchannel chip according to this example was obtained in the same manner as in Example 1.
Furthermore, in the microchannel chip according to this example, after post-baking, the elastic modulus and Vickers hardness were measured in the same manner as in Example 1. In this example, the measured result of the elastic modulus was 0.7 GPa, and the measured result of the Vickers hardness was 0.8 HV.

Example 4
An acrylic resin was used as the photosensitive resin to be applied onto the glass substrate, and the post-baking temperature was set to 150° C. Except for this, the microchannel chip according to this example was obtained in the same manner as in Example 1.
In this example, the measured elastic modulus was 1.5 GPa, and the measured Vickers hardness was 1.3 HV.
Example 5
The photosensitive resin applied to the glass substrate was the same acrylic resin as in Example 4. The exposure dose in the second exposure step using the proximity exposure device was 130 mJ/ ^cm2 , and the post-bake temperature was 120° C. Otherwise, the microchannel chip according to this example was obtained in the same manner as in Example 1.
In this example, the measured elastic modulus was 2.5 GPa, and the measured Vickers hardness was 20 HV.

Example 6
The photosensitive resin applied to the glass substrate was the same acrylic resin as in Example 4. The exposure dose in the second exposure step using the proximity exposure device was 170 mJ/ ^cm2 , and the post-bake temperature was 150° C. Otherwise, the microchannel chip according to this example was obtained in the same manner as in Example 1.
In this example, the measured elastic modulus was 5 GPa, and the measured Vickers hardness was 40 HV.
Example 7
The photosensitive resin applied to the glass substrate was the same acrylic resin as in Example 4. The exposure dose in the second exposure step using the proximity exposure device was 170 mJ/ ^cm2 , and the post-bake temperature was 150° C. Otherwise, the microchannel chip according to this example was obtained in the same manner as in Example 1.
In this example, the measured elastic modulus was 5.1 GPa, and the measured Vickers hardness was 42 HV.

(Example 8)
A negative liquid epoxy resin (negative liquid resist) was used as the photosensitive resin to be applied to the glass substrate. The exposure dose in the second exposure step using the proximity exposure device was 500 mJ/ ^cm2 , and the post-bake temperature was 250°C. Otherwise, the microchannel chip of this example was obtained in the same manner as in Example 1.
In this example, the measured elastic modulus was 10 GPa, and the measured Vickers hardness was 80 HV.

(Comparative Example 1)
A micro-channel chip according to this comparative example was obtained in the same manner as in Example 8, except that the post-baking temperature was set to 300°C.
In this comparative example, the measured elastic modulus was 11.7 GPa, and the measured Vickers hardness was 20.8 HV.
(Comparative Example 2)
A microchannel chip was obtained in the same manner as in Comparative Example 1, except that the exposure dose in the second exposure step using the proximity exposure device was set to 600 mJ/cm ² .
In this comparative example, the measured elastic modulus was 14.2 GPa, and the measured Vickers hardness was 30.4 HV.

<Evaluation>
(Bonding condition test)
For the microchannel chips of Examples 1 to 8 and Comparative Examples 1 and 2, 10 μL of the colored reaction solution was collected with a pipette and introduced into the inlet port of the channel, and the state of the liquid transfer was observed under a microscope.
Based on the observation results, the bonding state between the partition layer and the cover layer of the microchannel chip was evaluated using two levels of "good" and "bad" according to the following criteria.
<Evaluation criteria>
◯: No liquid leakage from inside the flow channel was observed at the joint between the partition layer and the cover layer. ×: Liquid leakage from inside the flow channel was observed at the joint between the partition layer and the cover layer.

(Beads passage test)
The microchannel chips of Examples 1 to 8 and Comparative Examples 1 and 2 were subjected to the following bead passage test.
30 parts by mass of microbeads with a diameter of 40 μm were added to 100 parts by mass of the colored reaction solution and stirred. 10 μL of the reaction solution was collected using a pipette so as to contain 10 or more microbeads, and the collected reaction solution was observed under a microscope to count the number of microbeads in the solution. The reaction solution in the pipette was then introduced into the flow channel from the input port of the microchannel chip and sent to the output port. The reaction solution was collected at the output port and observed under a microscope, and the number of microbeads in the reaction solution was counted again.
Based on the results of the remeasurement, the state of bead passage through the microfluidic chip (degree of retention due to deformation of the channel) was evaluated using three levels of "Good", "Good", and "Poor" according to the following criteria. <Evaluation criteria>
◯: The number of microbeads in the solution recovered at the output unit is 90% or more of the number measured before the liquid is sent. △: The number of microbeads in the solution recovered at the output unit is 70% or more of the number measured before the liquid is sent. ×: The number of microbeads in the solution recovered at the output unit is less than 70% of the number measured before the liquid is sent.

The evaluation results for the examples and comparative examples are shown in Table 1, along with the process conditions for the microchannel chip.

As shown in Table 1, the microchannel chips of Examples 1 to 8 all passed the bonding condition test ("Good"), with no leakage from the channels and good fluid transfer. Furthermore, the microchannel chips of Examples 1 to 8 all passed the bead passage test ("Good" or better), indicating that the impact of beads remaining in the channels due to deformation (plastic deformation) caused by the low height of the partition layer was limited and did not pose a problem in practical use. Furthermore, the microchannel chips of Examples 2 and 5 to 8 also passed the bead passage test ("Good"), indicating good results. In other words, it was found that the microchannel chips of Examples 1 to 8 are able to suppress bonding failure between the resin layer forming the channel and the lid material and deformation of the channel.

On the other hand, the microchannel chips of Comparative Examples 1 and 2 all failed the bonding condition test ("X"). This is because the elastic modulus of the partition layer in Comparative Examples 1 and 2 was excessively high (exceeding 10 GPa), making it unable to conform to slight unevenness, resulting in gaps when bonding with the cover layer, and causing liquid leakage from within the channel at the bonded points between the partition layer and cover layer.

From the above, it was confirmed that the microchannel chip of this example can suppress the occurrence of poor bonding between the resin layer forming the channel and the lid material and deformation of the channel by controlling the elastic modulus and Vickers hardness of the partition layer.
Specifically, it was found that, as in the microchannel chips of Examples 1 to 8, when the elastic modulus of the partition layer was within the range of 1 MPa to 10 GPa, the occurrence of poor bonding between the resin layer forming the channel and the lid material and deformation of the channel could be suppressed. It was also found that, when the elastic modulus of the partition layer was within the range of more than 2 GPa to 10 GPa, the occurrence of poor bonding between the resin layer forming the channel and the lid material and deformation of the channel could be suppressed. Furthermore, it was also found that, as in the microchannel chip of Example 2, when the elastic modulus was within the range of 1 MPa to 2 GPa and the Vickers hardness was 2HV or higher, the occurrence of poor bonding between the resin layer forming the channel and the lid material and deformation of the channel could be suppressed.

Furthermore, it is presumed that the difference in the results of the bead passage test between Examples 2, 5 to 8 and Examples 1, 3 and 4 is due to the influence of a Vickers hardness of 2HV or more. In other words, a Vickers hardness of 2HV or more more reliably suppresses plastic deformation of the partition layer, which is presumed to be advantageous in evaluating the suppression of flow path deformation (bead passage).

The microchannel chip and microchannel chip manufacturing method disclosed herein are not limited to the above-described embodiments and examples, and various modifications are possible within the scope that does not impair the characteristics of the invention.

The present invention can be used effectively as a high-quality microchannel chip and its manufacturing method that eliminates bonding defects and channel deformation by controlling the elastic modulus and Vickers hardness of the partition layer in microchannel chips intended for research, diagnostic, testing, analysis, culturing, etc.

1, 102, 103 Microchannel chip 2 Input section 3, 23, 33 Channel section 4 Output section 10, 20, 30 Substrate 11, 21, 31 Partition layer 12, 22, 32 Cover layer 24, 34 Adhesion layer

Claims (12)

A substrate;
a partition layer made of a resin material and provided on the substrate to form a flow path;
a cover layer provided on a surface of the partition wall layer opposite to the substrate,
the elastic modulus of the partition wall layer is in the range of more than 2 GPa and not more than 10 GPa,
the partition wall layer contains only one type of resin material;
A microchannel chip characterized by: A substrate;
a partition layer made of a resin material and provided on the substrate to form a flow path;
a cover layer provided on a surface of the partition wall layer opposite to the substrate,
the elastic modulus of the partition wall layer is in the range of 1 MPa or more and 2 GPa or less,
The partition wall layer has a Vickers hardness of 2 HV or more,
the partition wall layer contains only one type of resin material;
A microchannel chip characterized by: the resin material contained in the partition layer is only one of polydimethylsiloxane, a urethane acrylate resin, an acrylic resin, and an epoxy resin;
3. The microchannel chip according to claim 1 or 2. The partition wall layer has a Vickers hardness of 2 HV or more.
3. The microchannel chip according to claim 1 or 2. The cover layer has a higher elastic modulus than the partition wall layer.
The microchannel chip according to claim 1 . The cover layer has a lower elastic modulus than the partition wall layer.
The microchannel chip according to claim 1 . the resin material forming the partition wall layer is a photosensitive resin that is photosensitive to light having a wavelength of 190 nm or more and 400 nm or less, which is in the ultraviolet light region;
The microchannel chip according to any one of claims 1 to 6. A step of applying a resin onto a substrate;
exposing the coated resin to light;
developing and washing the exposed resin to form a partition wall layer that defines flow paths on the substrate;
post-baking the barrier layer;
bonding a cover layer to a surface of the partition wall layer opposite to the substrate;
Including,
The elastic modulus of the partition wall layer is set to be in the range of more than 2 GPa and not more than 10 GPa,
the partition wall layer contains only one type of resin material;
1. A method for producing a microchannel chip comprising: The Vickers hardness of the partition wall layer is 2 HV or more.
The method for producing the microchannel chip according to claim 8. the elastic modulus and Vickers hardness of the barrier layer are controlled by the post-baking treatment.
The method for producing the microchannel chip according to claim 9 . the elastic modulus and the Vickers hardness of the partition wall layer are controlled by the amount of ultraviolet light exposure in the step of exposing the resin.
The method for manufacturing a microchannel chip according to claim 9 or 10. In the step of exposing the resin, the photosensitive resin is exposed to light having a wavelength of 190 nm or more and 400 nm or less, which is in the ultraviolet light region.
The method for manufacturing a microchannel chip according to any one of claims 8 to 11.