JP7570664B2 - Microfluidic chip production method - Google Patents

Description

The present invention relates to a method for producing a microchannel chip, and in particular to a method for joining plates that constitute a microchannel chip.

Microfluidic chips are capable of transporting, mixing and measuring fluids such as aqueous solutions in tiny spaces. This has led to a wide range of applications, including optical and electrical analysis of viruses, proteins and DNA, as well as cell culture and capture.

A microfluidic chip basically consists of a plate (channel plate) on which the channels and wells (reservoirs) are formed, and a plate (cover plate) on which the inlet/outlet for injecting/removing samples at the ends of the channels or at specified locations are formed, and the main materials used for these are cycloolefin polymer (COP), polymethylmethacrylate resin (PMMA), polystyrene (PS), polycarbonate (PC), etc. The channel plate and cover plate are fitted together without any gaps and bonded together to complete the channel etc. between the two plates.

Conventional methods for such bonding include heat fusion, ultrasonic fusion, adhesion using double-sided tape or silane coupling agents, heat press bonding, and solvent bonding. In the case of heat press bonding, both bonding surfaces are usually treated with ultraviolet light or plasma in advance.

WO2011-010738 JP 2013-132822 A No. WO2018-159257

When producing a microchannel chip by bonding a channel plate and a cover plate, the following quality is required for the bonding of the two plates .
(1) There must be no deformation of the flow channel or change in optical properties when the material is joined.
(2) After joining, there must be sufficient joint strength (water resistance, pressure resistance, and ability to prevent the two plates from peeling off).
(3) There is no elution of substances that may affect cells, etc. from the joint.

Patent Document 1, which concerns the manufacturing process of liquid crystal display panels, discloses a bonding technique for bonding different types of films with different materials and characteristics together, or for bonding glass and a film. In this technique, a bonding medium layer made of one or more selected from the group consisting of hydrogen gas, water vapor gas, alcohol gas, hydrogen peroxide gas, organometallic compounds, and silane coupling agents is formed on the bonding surfaces, and bonding materials (plate materials) are layered on top of each other via the bonding medium layer, and then heated and/or irradiated with electromagnetic waves to bond them. This technique aims to prevent deterioration of optical properties and ensure sufficient bonding strength, but does not fully consider the above point (3).

Patent Document 2 discloses a technique in which at least one of the first and second substrates, which are made of a resin material, is brought into contact with plasma, heated to 70°C or higher with water present on the surface, and then bonded by superimposing the two substrates and heat pressing them near the glass transition point (Tg). According to this document, it is possible to bond two substrates firmly with high dimensional accuracy without causing any alteration or deterioration of the substrates. However, since the process includes a heat pressing process near the Tg, alteration and deterioration are unavoidable depending on the type of substrate (plate material).

Patent Document 3 discloses that by exposing the joining surfaces of two cycloolefin polymer (COP) plates, or a COP plate and a glass plate, to _H2O plasma and then bringing the two joining surfaces together, the plates can be joined without applying large pressure or temperature and without changing the optical properties.

However, when producing a microchannel chip, it is not enough to simply be able to join the plates that make up the chip; the channel formed between the plates must be suitable for flowing samples. In other words, when a sample, which is often an aqueous solution, is flowed through a channel with a small cross-sectional area, if the inner surface of the channel is hydrophobic, the surface tension of the water makes it difficult for the sample to flow through the channel.

The present invention was made to solve these problems of the prior art, and its purpose is to provide a method for producing microchannel chips that does not apply large pressure or temperature, does not affect the object being measured, and ensures the hydrophilicity of the channels.

The present invention, which has been made to solve the above problems, provides a method for producing a micro-channel chip by bonding a first plate and a second plate that constitute a micro-channel chip, comprising the steps of:
exposing the bonding surface of the first plate and the bonding surface of the second plate to _H2O plasma;
Bringing the joining surface of the first plate and the joining surface of the second plate close to each other with water interposed therebetween;
The method further comprises the step of maintaining the above-mentioned state in an environment of 5 to 60° C. for 1 minute to 200 hours to remove water from between the two bonding surfaces.

Here, "bringing the joining surfaces of the first plate and the second plate close together with water between them" means that even when the first plate and the second plate are held vertically, the water is not expelled from between the two joining surfaces due to surface tension, but is instead held between the two joining surfaces.

Methods for placing water between the joining surfaces of the first and second plates include forming a water film on both or either one of the surfaces (laying the joining surfaces horizontally and forming a water film on the surface) and then joining the two joining surfaces together, as well as immersing the first and second plates in water and bringing the two joining surfaces closer together. In any case, when the two surfaces are brought close together, a water film is formed between them due to the surface tension of the water.

In this state, when the step of removing water between the two joining surfaces is carried out under the above conditions, the joining surface of the first plate and the joining surface of the second plate are joined.

The first and second plates constituting the microfluidic chip that is the subject of the above method are made of cycloolefin polymer (COP), cycloolefin copolymer (COC), polymethylmethacrylate resin (PMMA), polystyrene (PS), polycarbonate (PC), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polydimethylsiloxane (PDMS), silicon wafer, glass, etc.

In the above method, it is preferable that the surface roughness of each joining surface of both plates is Ra10nm or less.

Moreover, the power of the H ₂ O plasma to which both bonding surfaces are exposed (i.e., the power of the high frequency power generating the H ₂ O plasma) is preferably 10 to 400 W/1200 cm ^2. By setting the H ₂ O plasma power in this manner, bonding is ensured and the optical properties and other characteristics of the first and second plates are not changed.

In addition, it is preferable that the plasma pressure at this time is about 1 to 200 Pa.

In addition, it is preferable that the bonding surface is exposed to plasma for 2 to 600 seconds.

In this case, " _H2O plasma" refers to plasma with a partial pressure of _H2O of 20% or more, and the plasma gas may contain small amounts of other gases other than _H2O , such as oxygen ( _O2 ), nitrogen ( _N2 ), ammonia ( _NH3 ), hydrogen ( _H2 ), argon (Ar), helium (He), etc.

The method according to the present invention can bond the first and second plates constituting the microchannel chip without applying large pressure or temperature. Furthermore, since only water is used during bonding, substances that affect the object to be measured do not flow out or seep from the first and second plates constituting the microchannel chip into the channel, etc., and do not affect the measurement of biological samples using this microchannel chip. Furthermore, since the hydrophilicity of the inner surface of the channel can be ensured, a microchannel chip with low channel resistance can be produced.

Plan view of the flow channel plate of the test piece used in the bonding test (a), plan view of the cover plate (b), and central cross-sectional view of both plates joined together (c). FIG. 13 is a schematic diagram of a plasma processing apparatus used for H ₂ O plasma processing of the bonding surfaces. 1 is a flowchart showing the flow of a joining method. FIG. 1 is a diagram for explaining a water resistance and pressure resistance test. FIG. 4 is a diagram showing each bonding condition of the examples and the comparative examples. Plan views of the test piece before the test (a), the test piece that passed the water resistance and pressure resistance test (b), and the test piece that failed the test (c). FIG. 4 shows the evaluation results of Examples and Comparative Examples.

A preferred embodiment of the present invention will be described below with reference to the drawings.

<1. Test piece>
In this embodiment, COP plates were used for both the first and second plates. The COP plate used was a 1 mm thick ZEONEX690R (glass transition temperature 136°C) manufactured by Zeon Corporation, which was cut into a size of 25 mm x 60 mm to prepare a test piece. Three of these test pieces were used as one set to carry out various tests. In one of the three test pieces, a meandering flow path 12 with a width of 300 μm, a depth of 50 μm, and a total length of 16 mm was formed by a thermal imprinting method (this is referred to as the flow path plate 11, FIG. 1(a)). In the other test piece, a liquid delivery hole 14 with a diameter of 1.8 mm was formed with a pin vice at positions corresponding to both ends of the flow path of the flow path plate 11 (this is referred to as the cover plate 13, FIG. 1(b)). The remaining test piece was not processed in any way, and the contact angle of pure water was measured with this (this is referred to as the contact angle measurement plate). One surface of each test piece (the surface on which the flow path was formed in the case of the flow path plate) was used as the main surface, and the surface was subjected to a plasma treatment or the like described below, and the main surfaces of the flow path plate 11 and the cover plate 13 were joined together. In addition, the water contact angle was measured on the main surface of the contact angle measurement plate. The surface roughness of the main surface was generally Ra 10 nm or less.

2. Plasma Processing Apparatus
The plasma processing apparatus used in the plasma processing described below will be described with reference to Fig. 2. Fig. 2 shows a schematic configuration of the plasma processing apparatus 20. As is clear from this figure, the plasma processing apparatus 20 is a parallel plate type (capacitively coupled type) plasma processing apparatus.

The plasma processing device 20 mainly comprises a plasma processing chamber 21 which forms a processing space inside in which the plate to be processed (the test piece) S is placed, a gas inlet section 30 which introduces plasma raw material gases, water (water vapor) _H2O or oxygen _O2 , into the processing space, an exhaust section 40 which evacuates the processing space, a pair of electrodes 24, 25 arranged opposite each other within the plasma processing chamber 21, and a control section 60 which controls each of these parts.

The gas introduction section 30 is provided with a water supply source ( _H2O ) 32 and an oxygen supply source ( _O2 ) 36, and a flow path is formed from the water supply source 32 to a gas introduction port 31 of the plasma processing chamber 21 via a vaporizer 33, a mass flow controller 34, and a valve 35. In addition, a flow path is formed from the oxygen supply source 36 to the gas introduction port 31 via a mass flow controller 37 and a valve 38. The exhaust section 40 is provided with a vacuum pump 42 and an opening/closing valve 43, and exhausts the processing space from an exhaust port 41 provided in the plasma processing chamber 21.

Of the pair of flat plate electrodes arranged vertically opposite each other in the plasma processing chamber 21, the upper electrode 24 is supplied with power from an RF power source 51 via a capacitor 52, and the lower electrode 25 is grounded. When RF power is supplied to the upper electrode 24, the gas introduced into the processing space is turned into plasma. The control unit 60 controls each of the above elements to perform the plasma processing described below.

2. Processing flow
As an embodiment of the present invention, the results of a bonding test of the flow path plate 11 and the cover plate 13 and a water contact angle measurement test using the contact angle measurement plate will be described. First, a method for the bonding test of the flow path plate 11 and the cover plate 13 will be described with reference to FIG .

First, the flow path plate 11 and the cover plate 13 were processed and prepared as described above (FIGS. 1(a) and (b)) (step S1). Next, the surface of the flow path plate 11 on which the flow path 12 was formed (bonding surface) and one surface of the cover plate 13 (bonding surface) were treated with _H2O plasma or _O2 plasma (step S2). These plasma treatments were performed using the plasma treatment device 20.

The H ₂ O plasma treatment will be described in detail. First, the flow path plate 11, the cover plate 13 and the contact angle measurement plate are carried into the plasma treatment chamber 21 through the carry-in port 22 of the plasma treatment chamber 21, and each test piece is placed on the lower electrode 25 with the main surface facing the upper electrode 24. Next, the carry-in port 22 is closed to seal the plasma treatment chamber 21, and then the treatment space is depressurized by exhausting the air with the exhaust unit 40. Then, water vapor is introduced into the treatment space by the gas introduction unit 30, and high-frequency power is input to the upper electrode 24. As a result, the water vapor introduced into the treatment space is turned into plasma to form H ₂ O plasma, and the plasma treatment of the bonding surface of each test piece exposed to the H ₂ O plasma proceeds. After a predetermined time has elapsed since the start of the treatment with the H ₂ O plasma, the valve 34 is closed to stop the supply of water vapor and the supply of high-frequency power, and the treatment is terminated.

The conditions for the _H2O plasma treatment used here were: water vapor inlet flow rate of 12 sccm, input high-frequency power of 50 W, pressure inside the treatment space of approximately 7 Pa, temperature during treatment of the lower electrode 25 on which the substrate S to be treated was placed of 25°C, and treatment time of 80 seconds.

The _O2 plasma treatment was performed under the same conditions except that the gas introduced into the treatment space in the plasma treatment chamber 21 was _O2 instead of _H2O .

After the plasma treatment was completed, the treatment space was returned to atmospheric pressure, and each test piece was removed from the plasma treatment chamber 21 and immediately tested for each of the following examples (steps S3 and S4). The specific test methods and results for each example are described below. The test methods are summarized in Figure 5 and the test results are summarized in Figure 7.

3. Testing of each Example
Example 1
The bonding surface (main surface) of each test piece was subjected to _H2O plasma treatment. Pure water at 25°C was dripped onto the flow path plate 11 taken out of the plasma treatment chamber 21 with a dropper so that the entire plate surface was completely covered (water film formation). The amount of pure water dripped was 0.15 mL (0.15 g) per square centimeter. In addition to dripping pure water, the method of forming a water film on the surface of this flow path plate 11 may also be a method of using a mist bottle or spraying water vapor in a chamber.

The cover plate 13 was placed on top of the water film formed on the surface of the flow path plate 11 so that the plasma-treated surface (main surface) was on the water film side (step S3), and in this state, it was left in an environment of 25°C without applying pressure ("relative pressure 0" in Figure 5) (step S4).

As a result, after 48 hours, the water film between the plates 11 and 13 had disappeared, and at that point the plates 11 and 13 were bonded together. This bonded structure is called a microchannel chip (Figure 6(a)) . No deformation or deterioration was observed in the microchannel chip or in the channel plate 11 and cover plate 13 that compose it (Figure 7).

Two tests were conducted to test the bonding state of the two plates 11 and 13. The first test was to check whether the microchannel chip was completely bonded in areas other than the channel 12. For this test, 3 μL of pure water was dropped from the liquid delivery hole 14 of the cover plate 13 using a micropipettor. In this case, water fills the channel 12 by capillary action without applying pressure. In the test of this Example 1, water did not leak between the two plates 11 and 13 outside the channel 12, and the water remained only within the channel 12 (Figure 6 (b)). This confirmed that in this Example 1, the channel plate 11 and the cover plate 13 were completely bonded in areas other than the channel 12.

Next, a test was conducted to examine the strength of the joint. A connector 15 and a tube 16 were fixed to both liquid delivery holes 14 of the microchannel chip (Figure 4), and compressed air was introduced into the flow channel 12 from one of the tubes 16 using a compressor. The compressed air was gradually increased in pressure until it reached a maximum of 200 kPaG (relative pressure to atmospheric pressure). Then, it was observed whether water leaked from the flow channel 12 to between the two plates 11 and 13. As a result, no water leak occurred in the test piece of Example 1 even when pressurized to 200 kPaG (Figure 7 "Water and pressure resistance"). In a commonly used microchannel chip, the water pressure resistance required when pressurizing and delivering a test liquid into the flow channel using a pump or the like is about 50 kPaG for a normal optical detection system flow channel, but a pressure resistance of about 200 kPaG is required for a microchannel chip that flows a large flow rate such as in flow cytometry. Since the microchannel chip of Example 1 exceeded this value, it was judged to be pass (○).

The pure water contact angle of the plasma-treated surface (main surface) of the contact angle measurement plate removed from the plasma treatment chamber 21 was measured using a contact angle meter (CA-D, manufactured by Kyowa Interface Science Co., Ltd.). A water contact angle of less than 90° is generally called hydrophilic, but when capillary liquid transfer is used in microchannel chips, a value of less than 50° is often required. For this reason, the criterion for judgment was set at less than 50°. The water contact angle of the contact angle measurement plate in Example 1 was 37°, which was less than the standard of 50° and therefore passed.

Example 2
After _H2O plasma treatment, the water film was formed on the surface (main surface) of the flow path plate 11 carried out of the plasma treatment chamber 21 underwater instead of by dropping water with a dropper. First, the flow path plate 11, the cover plate 13 and the contact angle measurement plate were immersed in pure water at 25°C, the flow path plate 11 and the cover plate 13 were stacked underwater, and then they were taken out and left to stand in the air at 25°C and 1 atm. The same procedure was followed as in Example 1, except that the plates were stacked underwater. It took 120 hours for the water film to disappear and for the joining of the flow path plate 11 and the cover plate 13 to be completed (the micro-flow path chip was formed).

After the bonding was completed, there was no deformation or deterioration in either the flow channel plate 11 or the cover plate 13. The micro-channel chip consisting of the flow channel plate 11 and the cover plate 13 had no liquid leakage during capillary transport and was water resistant. It also had a water pressure resistance of 200 kPaG or more. The water contact angle of the contact angle measurement plate was 34°, which was less than the standard of 50°.

Example 3
A water film was formed on the surface (main surface) of the flow path plate 11 that had been subjected to _H2O plasma treatment and was carried out of the plasma treatment chamber 21 by dropping water with a dropper, as in Example 1. After the water film was formed on the surface of the flow path plate 11, the cover plate 13 was placed on top of it so that the plasma-treated surface was on the water film side, and the plate was left to stand in a reduced pressure chamber at -20 kPa in an environment of 25°C. The same procedures were carried out as in Example 1, except for the environmental pressure. It took 68 hours for the water film to disappear and for the bonding of the flow path plate 11 and the cover plate 13 to be completed.

After bonding, there was no deformation or deterioration in the flow channel plate 11 and the cover plate 13. The micro-channel chip composed of the flow channel plate 11 and the cover plate 13 had no leakage of liquid during capillary transport and was water resistant. It also had a water pressure resistance of 200 kPaG or more.

The water contact angle of the contact angle measurement plate placed in the same environment was 14°, less than the standard of 50°.

Example 4
A water film was formed on the surface (main surface) of the flow path plate 11 that had been subjected to _H2O plasma treatment and was carried out of the plasma treatment chamber 21 by dropping water with a dropper, as in Example 1. The cover plate 13 was placed on the flow path plate 11 on which the water film was formed, and they were left stationary in a refrigerator at 10°C (atmospheric pressure). The procedure was the same as in Example 1, except for the stationary temperature. It took 168 hours for the water film to disappear and for the bonding of the flow path plate 11 and the cover plate 13 to be completed.

After bonding, there was no deformation or deterioration in the flow channel plate 11 and the cover plate 13. The micro-channel chip composed of the flow channel plate 11 and the cover plate 13 had no leakage of liquid during capillary transport and was water resistant. It also had a water pressure resistance of 200 kPaG or more.

The water contact angle of the contact angle measurement plate placed in the same environment was 43°, less than the standard of 50°.

Example 5
A water film was formed on the surface (main surface) of the flow path plate 11 that had been subjected to _H2O plasma treatment and was carried out of the plasma treatment chamber 21 by dropping water with a dropper, as in Example 1. The cover plate 13 was placed on the flow path plate 11 on which the water film was formed, and they were left stationary in a thermostatic chamber at 40°C (atmospheric pressure). The procedure was the same as in Example 1, except for the stationary temperature. It took 48 hours for the water film to disappear and for the bonding of the flow path plate 11 and the cover plate 13 to be completed.

After bonding, there was no deformation or deterioration in the flow channel plate 11 and the cover plate 13. The micro-channel chip composed of the flow channel plate 11 and the cover plate 13 had no leakage of liquid during capillary transport and was water resistant. It also had a water pressure resistance of 200 kPaG or more.

The water contact angle of the contact angle measurement plate placed in the same environment was 40°, less than the standard of 50°.

Example 6
A water film was formed on the surface (main surface) of the flow path plate 11 that had been subjected to _H2O plasma treatment and was carried out of the plasma treatment chamber 21 by dropping water with a dropper, as in Example 1. The cover plate 13 was placed on the flow path plate 11 on which the water film was formed, and they were left stationary in a thermostatic chamber at 55°C (atmospheric pressure). The procedure was the same as in Example 1, except for the stationary temperature. It took 48 hours for the water film to disappear and for the bonding of the flow path plate 11 and the cover plate 13 to be completed.

After bonding, there was no deformation or deterioration in the flow channel plate 11 and the cover plate 13. The micro-channel chip composed of the flow channel plate 11 and the cover plate 13 had no leakage of liquid during capillary transport and was water resistant. It also had a water pressure resistance of 200 kPaG or more.

The water contact angle of the contact angle measurement plate placed in the same environment was 43°, less than the standard of 50°.

(Comparative Example 1)
In this example, _O2 plasma treatment was performed instead of _H2O plasma treatment. The rest was the same as in Example 1. That is, water at 25°C was dropped with a dropper onto the flow path plate 11 taken out of the plasma treatment chamber 21 so that the entire surface of the plate was completely covered, forming a water film. The cover plate 13 was placed on top of it so that the plasma-treated surface (main surface) was on the water film side, and in this state, it was left stationary in an environment of 25°C without applying pressure. It took 48 hours for the water film to disappear and for the bonding of the flow path plate 11 and the cover plate 13 to be completed.

After bonding, there was no deformation or deterioration in the flow channel plate 11 and the cover plate 13. The micro-channel chip composed of the flow channel plate 11 and the cover plate 13 had no leakage of liquid during capillary transport and was water resistant. It also had a water pressure resistance of 200 kPaG or more.

However, the water contact angle of the contact angle measurement plate treated in the same way was 60°, which did not meet the standard of less than 50°.

(Comparative Example 2)
As in Example 1, the plasma treatment was _H2O plasma treatment. In addition, a water film was formed on the surface (main surface) of the flow path plate 11 carried out of the plasma treatment chamber 21 by dropping water with a dropper. The cover plate 13 was placed on the flow path plate 11 on which the water film was formed, and they were left stationary in a thermostatic chamber at 70°C (atmospheric pressure). It took 48 hours for the water film to disappear and for the bonding to be completed.

After bonding, there was no deformation or deterioration in the flow channel plate 11 and the cover plate 13. The micro-channel chip composed of the flow channel plate 11 and the cover plate 13 had no leakage of liquid during capillary transport and was water resistant. It also had a water pressure resistance of 200 kPaG or more.

However, the water contact angle of the contact angle measurement plate that was treated in the same way and placed under the same environment was 68°, which did not meet the standard of less than 50°.

(Comparative Example 3)
The plasma treatment was _H2O plasma treatment. However, the flow path plate 11 and the cover plate 13 were not subjected to water film formation on the surfaces (main surfaces) of the plate 11 and the cover plate 13 that were taken out of the plasma treatment chamber 21, and the plates 11 and 13 were stacked as they were. In this state, the plates were left to stand for 48 hours in an environment of 25°C and atmospheric pressure.

There was no deformation or deterioration in the flow channel plate 11 and the cover plate 13 after standing. However, when pure water was delivered by capillary flow from the delivery hole 14 of the cover plate 13, liquid leakage occurred from the flow channel 12 to between the plates 11 and 13. In other words, the micro-channel chip bonded by this method had no water resistance. In addition, the water pressure resistance was less than 1 kPaG.

The water contact angle of a contact angle measurement plate that was treated in the same way and placed under the same environment was 48°, meeting the standard of less than 50°.

(Comparative Example 4)
The test piece of Comparative Example 4 was treated using the method described in Patent Document 1. That is, in the plasma treatment, _O2 plasma treatment was performed instead of _H2O plasma treatment. A 0.14 g/ ^cm2 film was formed with a dropper on the surface (main surface) of the flow path plate 11 taken out of the plasma treatment chamber 21, and the cover plate 13 was placed on the water film. Then, the plates were placed on a hot plate at 126°C, which is 10°C lower than the glass transition temperature of 136°C of COP (ZEONEX690R), the material of the plates. The water film between the plates 11 and 13 disappeared in 10 minutes, and the flow path plate 11 and the cover plate 13 were bonded.

No deformation or alteration was observed in the channel plate 11 and cover plate 13 after treatment. However, the capillary fluid transfer test revealed that a large gap had formed in the center of the microchannel chip, indicating that a complete channel 12 had not been formed (Figure 6(c)). The water pressure resistance was less than 1 kPaG.

The water contact angle of a contact angle measurement plate treated in the same way was 69°, which did not meet the standard of less than 50°.

(Comparative Example 5)
The test piece of Comparative Example 5 was treated using the method described in Patent Document 2. That is, in the plasma treatment, the test piece was subjected to _O2 plasma treatment. The flow path plate 11 and the cover plate 13 taken out of the plasma treatment chamber 21 were placed on a hot plate at 70 ° C., and water vapor was sprayed onto each plate 11, 13 with a sprayer every minute to wet the surface (main surface) for 3 minutes. Thereafter, the cover plate 13 was placed on the flow path plate 11 without forming a water film, and heated at 126 ° C. for 5 minutes with a load of 0.2 MPaG applied by a heat press machine. The contact angle measurement plate was also heated at 126 ° C. for 5 minutes. The rest of the experiment was performed in the same manner as in Example 1.

No deformation or alteration was observed in the flow path plate 11 and cover plate 13 after treatment. No liquid leakage was observed in the capillary transport test, and they were water resistant. They also had a water pressure resistance of 200 kPaG or more. However, the water contact angle was 62°, which did not meet the standard of less than 50°.

11...flow path plate 12...flow path 13...cover plate 14...liquid supply hole 15...connector 16...tube 20...plasma processing device 21...plasma processing chamber 22...carry-in port 24...upper electrode 25...lower electrode 30...gas inlet 40...exhaust section 60...control section

Claims (5)

A method for producing a micro-channel chip by bonding a first plate and a second plate that constitute a micro-channel chip, comprising the steps of:
exposing the bonding surface of the first plate and the bonding surface of the second plate to _H2O plasma;
Bringing the joining surface of the first plate and the joining surface of the second plate close to each other with water interposed therebetween;
The method for producing a microchannel chip comprises the step of maintaining the above-mentioned state in an environment of 5 to 60°C for 1 minute to 200 hours to remove water from between the two bonding surfaces. The method for producing a microchannel chip according to claim 1, wherein the first plate and the second plate are made of the same material or a combination of two of the following materials: cycloolefin polymer (COP), cycloolefin copolymer (COC), polymethylmethacrylate resin (PMMA), polystyrene (PS), polycarbonate (PC), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polydimethylsiloxane (PDMS), silicon wafer, and glass. 3. The method for producing a microchannel chip according to claim 1, wherein the power of the H ₂ O plasma to which the bonding surface of the first plate and the bonding surface of the second plate are exposed is 10 to 400 W/1200 cm ² . 4. The method for producing a micro-channel chip according to claim 1, wherein the H ₂ O plasma has a pressure of 1 to 200 Pa. The microchannel chip production method according to any one of claims 1 to 4, wherein the bonding surface of the first plate and the bonding surface of the second plate are exposed to plasma for 2 to 600 seconds.

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