JP5218191B2 - Microchip substrate bonding method and microchip - Google Patents

Description

  The present invention relates to a method for bonding a microchip substrate having a microchannel and a microchip.

    Recently, research on miniaturization of chemical reactions and separation systems using microfabrication technology called microreactors and microanalysis systems has become active, and analysis of nucleic acids, proteins, etc. performed on microchips with microchannels Applications are expected for synthesis, rapid analysis of trace chemicals, and high-throughput screening of pharmaceuticals and drugs. As an advantage of such a micro system, it is considered to realize an inexpensive system that can be carried in a small space because the amount of sample and reagent used or the amount of discharged waste liquid is reduced. Further, by increasing the ratio of the surface area to the volume, it is possible to increase the speed of heat transfer and mass transfer. As a result, precise control of reaction and separation, high speed and high efficiency, and suppression of side reactions are expected.

  The microchannel is manufactured by bonding two members of a microchip substrate having microfabrication to at least one member. Until now, glass substrates have been mainly used as materials for microchip substrates. In order to create a fine flow path with a glass substrate, for example, there is a method in which a metal or a photoresist resin is coated on the substrate and a pattern of the fine flow path is baked and then an etching process is performed. Thereafter, the glass substrate is bonded by anodic bonding or the like (see Non-Patent Document 1). However, since extremely dangerous chemicals such as hydrofluoric acid are used for etching glass or patterns are baked one by one, it is very expensive for mass production.

  These microchips can be manufactured by injection molding even when various plastics are used. In injection molding, a molten thermoplastic material is introduced into a mold cavity, and the cavity is cooled to harden the resin, whereby a microchip can be manufactured efficiently and economically, and is suitable for mass production. As a method for bonding the substrates, a hot press, heat fusion using ultrasonic waves, a method using an adhesive, and the like are mainly performed (see Patent Document 1). However, the method using an adhesive has a problem that an excess of the adhesive is easily generated between the substrates, and the fine flow path is blocked and the inner wall is easily contaminated. The problem with the method by hot pressing is that it is accompanied by thermal deformation (heat shrinkage) because the material is partially melted and deposited by applying heat. As a result, the size and the accuracy of the position of the microchannel are hindered. In particular, the thermal shrinkage when a microchip substrate having voids inside is fused by hot pressing is remarkable. For example, when it is attempted to send liquid to the microchannel inlet of the microchip substrate through a connector installed on the substrate holder, it is difficult to send the liquid because it is out of the original position. As described above, it is very difficult to control the heat shrinkage in the heat fusion of the microchip substrate having the voids.

JP 2002-139419 A

Nobuaki Honda, Chemical Engineering, Vol. 66, No. 2, p71-74 (2002)

    An object of the present invention is to provide a bonding method for reducing thermal deformation of a substrate in bonding by thermal fusion of a microchip substrate having a gap.

The present invention is as follows.
(1) A method of bonding a first microchip substrate having a microchannel on a surface thereof and a second microchip substrate having a surface in close contact with a surface of the first microchip substrate having a microchannel, The first microchip substrate and / or the second microchip substrate have a void portion, and the first microchip substrate and / or the second microchip substrate are made of a plastic material, and the void portion includes a void portion. A method of joining microchips, wherein a substrate made of a material having a shape similar to that of the plastic material and having a lower thermal expansion coefficient than that of the plastic material is fitted and heated to be fused while being pressed.
(2) The microchip bonding method according to (1), wherein the material having a lower thermal expansion coefficient than plastic is a metal.
(3) The bonding of the microchip according to (1) or (2), wherein the plastic material includes at least one selected from polypropylene, polystyrene, polycarbonate, cyclic polyolefin, polymethylpentene, polymethyl methacrylate, polyethylene, and polyethylene terephthalate. Method.
(4) A microchip obtained by the microchip bonding method according to any one of (1) to (3).

    According to the present invention, since the thermal deformation of the substrate can be reduced in the bonding by thermal fusion of the microchip substrate having the void portion, it is possible to manufacture the microchip substrate with high accuracy.

Schematic plan view of one embodiment of a first microchip substrate used in the present invention Schematic plan view of one embodiment of a second microchip substrate used in the present invention Schematic plan view of a second microchip substrate Schematic plan view of an embodiment of a metal substrate used in the present invention Schematic plan view showing a state when the first microchip substrate and the second microchip substrate are bonded by the bonding method of the present invention. Schematic front view showing a state when the first microchip substrate and the second microchip substrate are bonded by the bonding method of the present invention.

Hereinafter, an example of an embodiment of a bonding method of a microchip substrate of the present invention will be described with reference to schematic diagrams shown in FIGS.
FIG. 1 is a schematic plan view of a first microchip substrate 1, which is a microchip body made of plastic having a microchannel 2 and a gap 7 on the surface.

  The fine channel in the channel device of the present invention preferably has a width of 1 μm or more and 1000 μm or less from the viewpoint of increasing the amount of sample or reagent used or the amount of waste liquid discharged and increasing the speed of heat transfer / mass transfer. 1 to 500 μm is preferable. However, the flow path design of these microchannels is not limited to the above because it is appropriately designed in consideration of the detection object and convenience. In addition, the microchannel function is equipped with microdevices, specifically membranes, pumps, valves, sensors, motors, mixers, gears, clutches, microlenses, electrical circuits, etc., or multiple microchannels on the same substrate It can be compounded by processing on top.

The shape and dimensions of the gap are not particularly limited and can be designed according to the method of use, but considering the ease of processing a substrate having the same shape as the gap for fitting into the gap A simple structure such as a square shape, a circular shape, a fan shape, or an uneven shape is preferable.
The microchip substrate having a void portion of the present invention may be used with another microchip substrate or member attached to the void portion.

    FIG. 2 is a schematic plan view of the second microchip substrate 11, which has a surface that can substantially adhere to the surface of the microchip main body having the microchannels, and the gap 7 of the first microchip substrate. And a microchip lid substrate having a gap 71 at substantially the same position. Furthermore, it has inlets 3 and 4 and an outlet 5. The microchip lid substrate may not have a gap.

  The material of the microchip body and the microchip lid substrate is not particularly limited as long as the interface has a property of melting and fusing by heat, but it can be melted when selected and heated according to the application and is solid at room temperature. It is preferable to use a plastic material. More preferably, polypropylene, polystyrene, polycarbonate, cyclic polyolefin, polymethylpentene, polymethyl methacrylate, polyethylene, and polyethylene terephthalate are preferably used as the plastic material in consideration of fastness and durability at normal temperature.

3 is a schematic plan view of a metal substrate that matches the size of the gap of the microchip body of FIG. 1 and the microchip lid substrate of FIG.

  The substrate to be fitted into the microchip body and the microchip lid substrate is not particularly limited as long as it has a lower thermal expansion coefficient than the plastic material used for the microchip, but is preferably made of metal. Furthermore, it is most preferable that it is SUS with good workability. Further, if there are a plurality of microchip gaps, a plurality of substrates can be fitted. The coefficient of thermal expansion indicates the rate at which the length or volume expands due to temperature rise per 1 K (° C). When the length changes, the linear expansion coefficient, and when the volume changes It is often expressed by a volume expansion coefficient, and the thermal expansion coefficient may be compared by a linear expansion coefficient or a volume expansion coefficient.

    FIG. 4 is a schematic plan view showing a state when the substrates of FIGS. 1 and 2 are bonded. FIG. 5 is a schematic front view of FIG. That is, after superposing the metal substrate of FIG. 3 on the microchip body of FIG. 1 and the microchip lid substrate of FIG. 2, heating was performed from the outside of one or both of the substrates. Bonding is performed by applying pressure through a pressure plate and fusing the substrate interface. After the fusion, the plastic of the microchip body tends to shrink due to heat shrinkage, but since there is a metal substrate that is fitted, only the shrinkage of the metal is shrunk in the flow direction of the microchannel 2. . Thereby, the plastic of the microchip body can control thermal shrinkage.

    The substrate to be fitted with the gap portion has the same shape as the gap portion and has almost the same dimensions, but the plane size is preferably smaller by 0.01 mm to 2 mm. If it is less than the lower limit value, it is not preferable because it is difficult to fit the substrate into the gap and to remove it after pressure bonding. When the upper limit is exceeded, the difference between the plastic and the shrinkage is widened, and the effect of the present invention is not exhibited.

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.
Example 1
A saturated cyclic polyolefin resin is used, and a microchannel 2 having a width of 200 μm, a depth of 200 μm, and a length of 60 mm, and a void 7 having a size of 15 mm × 50 mm × height of 2 mm are shown in FIG. The substrate thus arranged was molded by injection molding to obtain a microchip body.
Saturated cyclic polyolefin resin, 40 mm × 80 mm, 2 mm in thickness, located at both ends of the flow path of the microchip body, 1.0 mmφ inlets 3, 4 and outlet 5, 15.0 mm × 50. A substrate in which gaps 71 of 0 mm × 2 mm in height were arranged at two locations as shown in FIG. 2 was molded by injection molding to obtain a microchip lid substrate.
Next, a SUS substrate having a size of 14.8 mm × 49.8 mm × thickness 2.0 mm as shown in FIG. 3 was obtained by cutting.
Next, after the SUS substrate is fitted into the gap 7 of the microchip body, the surface having the flow path of the microchip body and the microchip lid substrate are overlapped, the substrate interface is thermally fused, and the SUS substrate is cooled and cooled. Removal gave a microchip. Linear expansion coefficient of the saturated cyclic polyolefins in this case, 7 × 10- ⁵ / ℃, linear expansion coefficient of SUS was 2 × ^{10 -5} / ℃. Thermal fusion was performed at 130 ° C. and 1000 N for 20 minutes. This was carried out three times to obtain three microchips.
Table 1 shows the distance between the inlet 3 and the outlet 5 before heat fusion and after heat fusion.

(Comparative Example 1)
Prepare a microchip body and a microchip lid substrate having the same dimensions, shape, and material as in Example 1, and superimpose the microchip body on the surface having the flow path and the microchip lid substrate, without using the SUS substrate Was heat-sealed to obtain a microchip. This was done three times. Table 1 shows the distance between the inlet 3 and the outlet 5 before heat fusion and after heat fusion.

Comparing the results of the example and the comparative example, in the example, it can be seen that the difference in the distance between the inlet 3 and the outlet 5 before and after heat fusion is lower than that of the comparative example. Further, the variation in shrinkage amount was also lower when comparing the example and the comparative example, indicating that the fusion was stably performed.
From the above results, it was shown that the microchip bonding method of the present invention is effective.

1 First microchip substrate (microphone chip body)
2 Microchannel 3 Inlet 4 Inlet 5 Outlet 6 Metal substrate 7, 71 Cavity 11 Second microchip substrate (microchip lid substrate)

Claims (4)

A method of bonding a first microchip substrate having a microchannel on a surface thereof and a second microchip substrate having a surface in close contact with a surface of the first microchip substrate having a microchannel, The chip substrate and / or the second microchip substrate has a void portion, and the first microchip substrate and / or the second microchip substrate are made of a plastic material, and the void portion has the same shape as the void portion. A method of joining microchips, comprising: inserting a substrate made of a material having a lower thermal expansion coefficient than that of the plastic material, and heating and welding while pressing. 2. The method of joining microchips according to claim 1, wherein the material having a lower thermal expansion coefficient than plastic is a metal. The method for joining microchips according to claim 1 or 2, wherein the plastic material contains at least one selected from polypropylene, polystyrene, polycarbonate, cyclic polyolefin, polymethylpentene, polymethyl methacrylate, polyethylene, and polyethylene terephthalate. A microchip obtained from the microchip bonding method according to claim 1.

Images