JP2012170854A - Micromixer, and method for manufacturing micromixer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a micromixer which can efficiently divide flow paths and make them confluent, as well as a method for manufacturing the micromixer.SOLUTION: This micromixer comprises a mixing part which includes a plurality of continuous mixer compartments. Each mixer compartment includes a first dividing wall 71 which bifurcates the entire flow path into an upper flow path and a lower flow path, a second dividing wall 72 which divides the entire flow path into a left side flow path and a right side flow path, and runs continuously with the downstream side of the first dividing wall 71, a first guide wall 73 which guides the upper flow path to either a right or a left flow path, and a second guide wall 74 which guides the lower flow path to the other of the right or the left flow path. In addition, a coating is formed over the extent excepting an area where a flow path is constituted, of the surfaces of the upper and lower parts of a base (a primary coating forming process). In this extent and also, the extent including the surface where the first dividing wall 71 is formed, a coating is formed (a secondary coating forming process). Following these processes, the coating formed by the second coating forming process is removed after etching in an appropriate depth from the upper surface. Finally, an etching work is performed in an appropriate depth from the upper and lower surfaces of the base.

Description

  The present invention relates to a micromixer and a manufacturing method thereof, and more particularly to a micromixer formed by deep etching a thin film substrate and a manufacturing method thereof.

  In the field of chemical synthesis and the like, there is an urgent need for a technique for performing a reaction / analysis of a trace fluid with high sensitivity in a short time using a small apparatus. In particular, micro-TAS (Micro Total Analysis Systems), in which elements necessary for chemical synthesis and analysis such as microchannels, pumps, valves, and sensors are miniaturized and integrated by microfabrication technology, is drawing attention. Among micro-TAS, there is a micromixer as an important element for reagent synthesis. By this micromixer, the necessary reagents are reduced to a small amount, and control performance of reaction variables such as reagent flow rate, reaction time, heating, cooling, etc. Can be improved. Therefore, chemical synthesis can be performed with high efficiency and safety.

  However, in a microchannel (microchannel) formed with fine dimensions, both the channel size and the flow velocity are small, so the Reynolds number is inevitably small, and turbulence hardly occurs in the microchannel. It is known to be laminar.

  Accordingly, in the mixing of fluids, molecular diffusion due to the contact interface between the fluids is dominant, and the fluids may not be mixed efficiently to the extent that they are simply joined together. Therefore, as means for efficiently mixing the fluid in the microchannel, an active mixer that is stirred by a piezo element or an external magnetic field has been proposed (see Non-Patent Documents 1 and 2), and the secondary flow is caused by a microstructure. A passive mixer that promotes the above has been proposed (see Non-Patent Document 3).

  Among these micromixers, the active mixer has the advantage that it can be effectively mixed in a short flow path, but the manufacturing process for integrating the actuation function is complicated, and an external power supply is also required. It was what I needed. On the other hand, since the passive mixer has a structure that causes a secondary flow, the flow path structure has to be complicated, and pressure loss is caused, resulting in variations in the performance of each channel.

  In order to solve these problems, passive mixers have been proposed in which the liquid layer is repeatedly divided and mixed, the thickness of the liquid layer is reduced exponentially, and the diffusion distance of molecules is shortened (Non-Patent Documents 4 and 5). reference). However, since the passive mixer described above is manufactured by laminating and laminating a three-dimensional flow channel structure, the process becomes complicated, and the mixer performance is affected by shifting the bonding portion. There was a problem of being.

Z. Yang, et al, Sensors and Actuators A, 93, pp. 266-272 (2001) K. S. Ryu, et al, Proc. mTAS '03, pp. 635-638 (2003) A. D. Strook, et al, Science, 295, pp. 647-651 (2002) J. et al. Blanebjerg, et al, Proc. MEMS '96, pp. 441-446 (1996) W. H. Tan, et al, JSME Int. J. et al. Series C, 48, 4, pp. 425-435 (2005) T.A. Noda, et al, Proc. mTAS '08, pp. 1057-1059 (2005) T.A. Saito, et al, APCOT'10, BMF11 (2010)

  Therefore, the inventors of the present application have eroded from both surfaces of a thin film substrate by using a semiconductor process technology, in particular, a deep reactive ion etching (DRIE) technology, to produce a three-dimensional channel structure. A micromixer was proposed (see Non-Patent Documents 6 and 7). As shown in FIG. 6, the proposed micromixer structure is provided with a dividing wall 171 that divides the flow path into left and right sides. In this configuration, an upper channel guide 172 that guides the road and a lower channel guide 173 that guides the channel in a direction different from the above while partially shielding the lower part of the channel. By such guide portions 172 and 173, an upper inlet and a lower inlet are provided in the entire cross section of the flow path, and the fluid passing through these flows into the left and right flow paths divided by the dividing wall 171. It was something that could be done.

  However, in the micromixer configured as described above, the velocity of the fluid flowing near the side wall of the flow path is slow, and the fluid flowing near the side wall is mixed regardless of the inlet located separately in the upper and lower sides. In some cases, it was left untouched. As a result, among the fluid immediately before the dividing wall, the fluid flowing upward and the fluid flowing downward are not clearly divided, and the entire fluid may not be sufficiently mixed.

  The present invention has been made in view of the above-mentioned points, and the object of the present invention is to efficiently divide and merge the flow paths by dividing them up and down immediately before dividing the flow paths into left and right. It is providing the micromixer which can be manufactured, and providing the method for manufacturing the said micromixer.

  Accordingly, the invention according to claim 1 according to the micromixer includes a supply unit that supplies a plurality of fluids, a mixing unit that mixes the plurality of fluids supplied from the supply unit, and a discharge that discharges the fluid after mixing. The mixing section has a plurality of continuous mixer sections, and each mixer section is a first dividing wall that branches the entire flow path into an upper flow path and a lower flow path A second dividing wall that divides the entire channel into a left channel and a right channel while continuing downstream of the first dividing wall, and the upper channel into one of the left and right channels. A first guide wall for guiding and a second guide wall for guiding the lower flow path to the other of the left and right flow paths are provided.

  According to the above configuration, the fluid is branched up and down by the first dividing wall immediately before the second dividing wall that divides the flow path into the left and right, and the fluid flowing near the side wall is also branched up and down. These can be guided to the left and right channels. Therefore, since the fluid branched up and down immediately before flowing into the left and right flow paths is forced to flow into the left and right flow paths, the fluid flowing in the vicinity of the flow path side walls can be mixed. It becomes.

  In the invention according to claim 2, the mixing unit includes a first mixer unit in which the upper channel is guided to the right channel and the lower channel is guided to the left channel; The upper flow path is guided to the left flow path, and the lower flow path is a mixing unit including a second mixer section guided to the right flow path.

  According to the above configuration, the fluid branched by the first dividing wall can pass through both the right channel and the left channel. This allows a part of the fluid flowing through the upper flow path to always pass through the right flow path or a part of the fluid flowing through the lower flow path in the state after passing through the plurality of mixer sections. As a whole, the fluid dispersion state can be advanced.

  The invention according to claim 3 is characterized in that the mixing section is a mixing section in which the first mixer section and the second mixer section are alternately arranged.

  According to the above configuration, the fluid that is branched by the first dividing wall and flows through the upper channel sequentially passes through the right channel and the left channel, and the fluid that flows through the lower channel is the left channel and the right channel. The fluid passes through the path sequentially, and when flowing through the second mixer section, the fluid flowing in the vicinity of the wall surfaces on the left and right sides of the flow path is appropriately dispersed by crossing each other.

  The invention according to claim 4 according to the method of manufacturing a micromixer includes a flow path forming step of forming a flow path at an appropriate position of a substrate having a predetermined thickness, and plate-like members on the upper surface and the lower surface of the substrate, respectively. The flow path forming step includes, on the upper surface of the substrate, a surface excluding a range where the supply unit, the mixing unit, and the discharge unit are formed, and a second division of the mixer unit A first film forming step of forming a film on the surface of the portion where the wall and the first guide wall are formed, and a surface of the film formed by the first film forming step and a first dividing wall. A second film forming process for forming a film on the surface of the substrate, a first etching process for etching from the upper surface of the substrate, a process for removing the film formed in the second film forming process, Etch from top surface Second etching step, and the surface of the lower surface of the substrate excluding the range where the supply unit, the mixing unit and the discharge unit are formed, and the surface of the part where the second dividing wall of the mixer unit is formed It is an erosion process including a third film forming process for forming a film on the substrate and a third etching process for etching from the lower surface of the substrate.

  According to the above configuration, in the first film forming process and the third film forming process, coatings are formed on the upper and lower surfaces of the substrate in the range where there is no need for etching processing among the substrates forming the micromixer. Furthermore, in the second film formation step, a film can be formed in a portion including a range where the first dividing wall is formed in addition to the range where the film is formed in the first film formation step. . Thereby, in the primary etching, a portion excluding the range where the film is formed in the secondary film forming step, that is, a portion of the supply portion and the discharge portion, and the mixing portion where the flow path is formed is etched. Can do. Further, by removing the film formed in the second film formation step and performing the second etching step, a portion for forming the surface of the first dividing wall on the portion to be eroded by the first etching step. The range in which the first divided wall that can be eroded in the included range and is not eroded only in the first etching is formed is not eroded with a thickness similar to the dimension corresponding to the depth of the etching. A part will be formed. Further, the first dividing wall can be formed inside the flow path by etching the back side of the substrate by the third etching.

  The invention according to claim 5 is characterized in that the substrate is a silicon substrate, and the first film formation step and the third film formation step are film formation steps for forming a silicon oxide film. .

  According to the above configuration, in the case of the thermal oxidation method, the film can be formed by oxidizing the substrate without stacking the film forming material. Further, when the coating method is used, a silicon oxide film at a predetermined location on the silicon substrate can be easily formed.

  According to a sixth aspect of the present invention, each of the etching steps is based on reactive ion etching (RIE), and the first etching step has a dimension corresponding to the thickness of the first dividing wall to be manufactured. An etching process that erodes to a greater depth than the second and third etching processes, in which the dimension of 1/2 of the dividing wall is subtracted from the dimension of 1/2 of the thickness of the substrate. It is an etching process that erodes to a depth of 2 mm.

  According to the above configuration, when the portion to be eroded to form the flow path is etched by the first etching step, the area where the first dividing wall is to be formed is not eroded and the depth thereof is reduced. The corresponding part remains as a non-erodible part. Then, the depth to be eroded to form the flow path (thickness of the substrate−thickness of the dividing wall) is eroded from the upper surface side of the substrate and also eroded from the lower surface side. Erosion (thickness of the dividing wall−thickness of the dividing wall) can erode the entire thickness of the substrate (entire part of the flow path), and at a position half the flow path depth. A first dividing wall can be formed. In the first etching step, the erosion to a depth larger than the thickness of the first dividing wall to be produced is already performed when etching is performed by reactive ion etching (RIE). Since the etching rate of the shallow surface which is not eroded is faster than the surface which has been eroded and deepened, the etching rate is taken into account and the erosion is greatly increased.

According to the present invention relating to the micromixer, for a plurality of different types of fluid that have flowed into one mixer section of the mixing section, the fluid is divided into a fluid that passes through the upper flow path and a fluid that passes through the lower flow path, Since the flow paths of these fluids can be converted to the left and right, the plurality of types of fluids can be divided into two layers and then mixed. Accordingly, by providing a plurality (n) of mixer sections in succession, the above division and mixing are repeated a plurality of times (n times), so that 2 ⁿ divisions and mixings are repeated. Thereby, a plurality of types of fluids can be sufficiently mixed. Further, if considering the molecular diffusion between fluids, by way of one mixer, the thickness of the divided layers 1/2, if via the n mixer, 1/2 ⁿ A very thin layer of aggregate fluid. And the fluid mixed by such a thin layer can expect the progress of molecular diffusion since the fluid of each layer approaches together.

  According to the present invention relating to the manufacturing method, the first dividing wall that divides the flow path up and down is formed by finally remaining portions that have not been eroded in the first etching step. The second dividing wall that is divided into left and right is formed by the part that has not been eroded remaining in the shape of a wall. Furthermore, a first guide wall that remains without being eroded is formed on the upper flow path side divided by the first dividing wall, and a second guide wall is similarly formed on the lower flow path side. The Rukoto. In this way, the upper flow path and the lower flow path divided by the first dividing wall are formed, and the upper and lower flow paths are respectively connected to either the left or right flow path by the first and second guide walls. It can be constituted as follows. In addition, the said flow path will function as a final flow path by laminating | stacking a plate-shaped member on the upper surface and lower surface of the board | substrate eroded by the said etching process.

It is explanatory drawing which shows the outline of embodiment concerning a micro mixer. It is explanatory drawing which shows the state of the board | substrate which comprises a micromixer. It is explanatory drawing which expands and shows one mixer part. It is explanatory drawing which shows the state of the fluid which passes the mixing part of a micromixer. It is explanatory drawing of embodiment concerning the manufacturing method of a micro mixer. It is explanatory drawing which shows the mixer part of the conventional micromixer. (A) is an enlarged photograph of the micromixer used in the experiment. (B) is an enlarged photograph showing the entire macro mixer used in the experiment. 6 is a graph of the measurement result of the fluorescence intensity of each channel in Experiment 1. FIG. In Experiment 1, it is the fluorescence micrograph of the fluid which passes through the inside of the flow path of a micromixer. 10 is a graph of the measurement result of the fluorescence intensity of each channel in Experiment 2. In Experiment 2, it is the fluorescence micrograph of the fluid which passes the inside of the flow path of a micromixer.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is an explanatory diagram showing an outline of an embodiment of the invention related to a micromixer. As shown in this figure, in this embodiment, smooth plate-like members B and C are laminated on both surfaces of a substrate A where a space through which a fluid can pass is formed, whereby a flow path is configured by the space of the substrate A. It is what is done. Therefore, a space having various functions is formed on the substrate A in a state where the plate-like members B and C are laminated.

  That is, on the substrate A, a region (supply unit forming region) 1 for forming a supply unit for supplying a fluid to be mixed and a region (mixing unit forming region) for forming a mixing unit for mixing the supplied fluid are formed. 2 and a region (discharge portion forming region) 3 for forming a discharge portion for discharging the mixed fluid. Each region 1, 2 and 3 is configured to penetrate the substrate A, and these constitute a flow path by the lamination of the plate-like members B and C.

  Furthermore, the supply part formation area 1 is comprised by the two branch flow path formation parts 11 and 12 and the one joint flow path formation part 13 in which these merge. As a result, the plate-like members B and C form two branch channels and one combined channel. The plate-like member B laminated on the upper surface of the substrate A is provided with fluid supply ports 4, 5, and when the plate-like member B is laminated on the substrate A, the supply ports 4, 5 are provided. Is continuous to the tips of the branch flow path forming portions 11 and 12, and fluid can be supplied to the branch flow path constituted by the branch flow path forming portions 11 and 12.

  Similarly, the discharge portion forming region 3 is configured by stacking the plate-like members B and C to form a discharge portion, and is configured by a flow path forming region 31 having an appropriate length. Further, the plate-like member B is provided with a discharge port 6, and when the plate-like member B is stacked, the discharge port 6 is provided so as to be continuous with the end of the flow path forming region.

  By the way, the mixing part forming area 2 is provided with an area (mixer part forming area) 21 in which a mixer part is formed, and before and after that, a flow for continuing to the supply part forming area 1 and the discharging part forming area 3 is provided. Regions (channel formation regions) 22 and 23 in which paths are formed are provided. The mixer part forming region 21 is formed by laminating the plate-like members B and C to form a plurality of mixer parts.

  Here, the mixer portion forming region 21 will be described in detail. FIG. 2 is a diagram showing details of the mixer section forming region 21, and FIG. 3 is a diagram showing one mixer section. As shown in FIG. 2, a plurality of mixer unit individual regions 7, 8... Are continuously provided in the mixer unit forming region 21, and each mixer unit individual region 7 has a first dividing wall. 71, a second dividing wall 72, a first guide wall 73, and a second guide wall 74 are provided. A first dividing wall (hereinafter, sometimes referred to as a horizontal dividing wall) 71 is provided near the center with respect to the direction of the thickness D of the substrate A while the plane portion is in the horizontal direction, and the flow path is located above the flow path. And the bottom part. The second dividing wall (hereinafter, sometimes referred to as a vertical dividing wall) 72 has a plane portion in a direction orthogonal to the plane portion of the horizontal dividing wall 71 and a direction of the channel width H of the entire channel. It is provided in the vicinity of the center, and the flow path is divided into left and right. Further, the guide walls 73 and 74 are both erected on the upper and lower surfaces of the horizontal dividing wall 71 while continuing to the vertical dividing wall 72.

  By configuring the mixer section individual area 7 as described above, as shown in FIG. 3, the flow path forming area 22 of the mixer section forming area 21 has a predetermined section by laminating the plate-like members B and C. A channel R having an area is formed. And in the mixer part individual area | region 7, the mixer part M will be formed. In the mixer section M, the flow path R is divided vertically by a horizontal dividing wall 71 and divided horizontally by a vertical dividing wall 72. At this time, among the channels divided vertically by the horizontal dividing wall 71, the upper side is referred to as an upper channel, and the lower side is referred to as a lower channel. Of the channels divided by the vertical dividing wall 72, the left side is referred to as the left channel and the right side is referred to as the right channel.

  Of the guide walls 73, 74, the first guide wall (hereinafter sometimes referred to as the upper guide wall) 73 is configured above the horizontal partition wall 71, and one of the flow paths R extends from the vertical partition wall 72. The slanted flat surface (guide surface) 75 is formed obliquely toward the wall surface R1, and the guide surface 75 reduces the upper flow path in the direction of the flow path width H. The fluid flowing through the upper channel can be guided to the right channel (because of this function, the guide surface that guides to the right channel may be referred to as the right guide surface below). Further, the second guide wall (hereinafter may be referred to as a lower guide wall) 74 is configured below the horizontal dividing wall 71 and extends from the vertical dividing wall 72 toward the other wall surface R2 of the flow path R. It has a slanted plane (guide surface) 76 that is slanted. The upper guide surface 76 guides the fluid flowing through the lower flow channel to the left flow channel while reducing the lower flow channel (from this function, the fluid is guided to the left flow channel in the following). The guide surface may be referred to as the left guide surface).

  The upper guide wall 73 and the lower guide wall 74 are configured such that, in a plurality of mixer units, the upper guide wall 73 is provided with a right guide surface and the lower guide wall is provided with a left guide surface. However, as shown in FIG. 2, in the next consecutive mixer section, the upper guide wall 73 is provided with a left guide surface and the lower guide wall 74 is provided with a right guide surface. It is good also as a structure. When three or more mixer units are arranged, the right guide surface and the left guide surface provided on the guide walls 73 and 74 may be alternately arranged. Furthermore, it is good also as a structure which replace | exchanges a right side guide surface and a left side guide surface about one or more mixer parts among several mixer parts.

  Moreover, in the said embodiment, in the supply part formation area for comprising a supply part, only the state (structure which supplies two types of fluids) in which the two branch flow path formation areas 11 and 12 are comprised is demonstrated. However, when three kinds of fluids are mixed, it is only necessary to provide three branch channels, and for that purpose, three branch channel forming regions may be provided. In addition, after mixing the fluid by the mixing unit, when considering the mixing of the fluid by molecular diffusion, the flow path from the mixing unit to the discharge unit may be configured to be long. In this case, the mixing portion formation region 2 and the discharge portion formation region 3 are provided close to each other, but any one of the flow path formation regions may be formed long in advance.

  Since the present embodiment is configured as described above, the fluid passing through the mixing section in the present embodiment is divided into upper and lower flow paths and then guided and mixed in the left and right flow paths. . That is, as shown in FIG. 4, among the fluids α and β flowing separately on both sides of the flow path R, the fluids α1 and β1 that pass through the upper flow path are both guided to the right flow path and pass through the lower flow path. Both the fluids α2 and β2 are guided to the left channel.

  Therefore, the fluid to be mixed is supplied from two branch channels (channels formed by the branch channel forming units 11 and 12 (see FIG. 1)), and the merge channel (the merge channel forming unit 13 ( 1), it can be assumed that one fluid flows exclusively on the left side of the entire channel and the other fluid exclusively flows on the right side. At this time, assuming that the fluid flowing on the left side is α (fluids α1, α2) in FIG. 4A, and the fluid flowing on the right side is β (fluids β1, β2) in FIG. When the two types of fluids α and β pass through the mixer unit 7, the fluids α and β are mixed in half.

Therefore, when n mixer parts are connected in succession, the fluid after passing through the n mixer parts is separated into ½ ⁿ respectively. Are alternately formed in layers. Furthermore, when molecular diffusion between fluids is taken into account, the fluids separated into 1/2 ⁿ diffuse to each other in the close state, so that mixing of fluids can be promoted.

  Next, a method for manufacturing the micromixer will be described. FIG. 5 is a diagram showing a method of manufacturing a micromixer centering on a mixer part (mixer part forming region) in the mixing part. In the manufacturing method of the micromixer, the mixing unit including the mixer unit, the supply unit, and the discharge unit all form the formation region of each unit by eroding the substrate A (flow path forming step), and finally the plate-like member Each part is constituted by laminating B and C (lamination process). Since the laminating process is performed by simply bonding the plate-like members B and C to the upper and lower surfaces of the substrate A after completion of the flow path forming process, here, the flow path forming process for the substrate A will be described. . In the description, when a name of each part (for example, a mixer part) is described, it means a formation area (for example, a mixer part formation area) of the part. In addition, in this drawing, the supply unit and the discharge unit are not shown, but by eroding at the same time as the mixing unit, a long hole that penetrates is formed, thereby constituting the flow path of each unit. The illustration is omitted.

  First, a mask material is formed in a range of the substrate A that is not eroded until the end (portion that does not become a flow path). That is, as shown in FIG. 5A, on the upper surface side of the substrate A, portions 81a and 82a constituting both sides of the flow path, the upper end surface 83a of the vertical dividing wall, and the upper end surface 84a of the upper guide wall are provided. Then, a mask material is deposited. This is the first film formation step. When the upper end face 84a of the upper guide wall is formed, the position of the film formation differs depending on whether the guide wall is the right guide surface or the left guide surface.

  Thus, the portion where the mask material is formed in the first film formation process is not eroded by the etching process in the next process. Therefore, the mask material is not formed on the portion where the flow path is formed (the portion to be the supply portion or the discharge portion). Since a mask material is formed on the surface of the substrate A on which no flow path is formed, the mask material is also formed on other portions of the substrate A that are not shown in FIG. It becomes.

  Note that the mask material can be formed using chromium oxide, chromium nitride, or the like by sputtering. When the substrate A is a silicon substrate, a silicon oxide film may be formed by thermal oxidation in an oxidizing atmosphere by a thermal oxidation method instead of the film formation method.

  Following the film formation step, a second film formation step is performed. FIG. 5B shows a state after film formation. As shown in this figure, in addition to the portion formed by the first film forming step, a film is formed on the surface of the portion 91 where the horizontal dividing wall is formed. As the film formation process here, a photoresist material can be formed using a photoresist. In addition, when a silicon oxide film is formed in the first film formation step, an aluminum film may be formed by sputtering in addition to forming a photoresist material. What is important is that the material of the film formed in the first film forming process is different from the material of the film formed in the second film forming process, so that only the film formed in the second film forming process is removed later. It is to be in a state that can be.

  Next, etching is performed from the upper surface side of the substrate A. This is called a primary etching process. FIG. 5C shows a state after the first etching process. As shown in this figure, since the film portion formed by the second film formation step is not eroded by etching, only the portions 101 and 102 where the film is not formed (portions are formed) are eroded. The At this time, the etching process can be performed by reactive ion etching (RIE) in addition to dry etching or wet etching. In the first etching step, since the portion corresponding to the horizontal dividing wall is formed, the etching depth should be adjusted and formed so that the necessary thickness remains in the horizontal dividing wall finally. It is about the same as the wall thickness of the horizontal dividing wall. When the subsequent etching is performed by RIE, the etching rate of the shallow surface that has not been eroded is faster than the surface that has already been eroded and deepened. It is adjusted to be slightly larger than the wall thickness of the horizontal dividing wall.

  Thereafter, the film formed by the third film forming process is removed from the upper surface of the substrate A. FIG.5 (d) is a figure which shows the state which removed the said film. As shown in this figure, by removing the coating film, the coating film formed by the first and second film formation steps remains, and the coating film at the portion where the horizontal dividing wall is formed is removed, and the division is performed. The upper surface portion 92 of the portion where the wall is to be formed appears on the surface.

  Next, etching is performed again from the upper surface side of the substrate A. This is called a secondary etching process. FIG. 5E shows the state after etching. As shown in this figure, the portions 101 and 102 where the flow path is formed and the upper surface portion 92 of the portion where the horizontal dividing wall is formed are eroded, and the respective surfaces are formed near the center in the thickness direction of the substrate A. The Rukoto. The etching at this time is also selected from methods such as dry etching, wet etching, or reactive ion etching.

  Thus, the processing of the upper surface of the substrate A is completed, and the processing of the lower surface of the substrate A is subsequently performed. First, a mask material is formed on the lower surface of the substrate A. This is called a third film formation step. FIG. 5F shows a state after the third film formation step. As shown in this figure, in the third film forming step, as in the first film forming step, portions 81b and 82b constituting both sides of the flow path and the lower portion of the vertical dividing wall are formed on the lower surface of the substrate A. A mask material is deposited on the end face 83b and the lower end face 85b of the lower guide wall. When forming the lower end face 85b of the lower guide wall of the upper guide wall, the position of the film formation differs depending on whether the guide wall is the right guide surface or the left guide surface.

  Here, on the lower surface of the substrate A, the portions 81b and 82b constituting both sides of the flow path and the lower end surface 83b of the vertical dividing wall are formed on the flow path sides 81a and 82a (see FIG. 5A) on the upper surface and vertical. The film is formed at a position symmetrical to the upper edge 83a of the dividing wall (see FIG. 5A) (position moved parallel to the thickness direction). As a result, the shape formed when the substrate A is etched from the upper surface and the shape formed when the substrate A is etched from the lower surface coincide with each other. It is designed to form a wall.

  On the other hand, the upper end face 84a of the upper guide wall and the lower end face 85b of the lower guide wall have different oblique portions, and the upper end face 84a and the lower end face 85b are formed by performing etching processing at an appropriate depth from the upper surface of the substrate A. The right guide surface is formed on the guide wall, and the left guide surface is formed on the lower guide wall by performing etching processing at an appropriate depth from the lower surface of the substrate A.

  Next, etching is performed from the lower surface of the substrate A. This is called a third etching step. FIG. 5G shows a state after etching. As shown in this figure, the portions 101 and 102 where the flow path is to be formed are all eroded and penetrated, and the portion where the horizontal dividing wall is to be formed is formed with the lower surface portion 93, and the upper surface portion 92 and A plate-shaped dividing wall having a predetermined thickness is formed between the two. The etching at this time can also be performed by a method such as dry etching, wet etching, or reactive ion etching.

  Thus, in order to finally form the horizontal dividing wall with a predetermined thickness, the etching depth from the lower surface of the substrate A is adjusted in the third etching step. That is, as shown in FIG. 5F, at the end of the second etching step, the flow path forming portions 101 and 102 remain, and the portion forming the horizontal dividing wall has a larger thickness. Therefore, by performing erosion at a depth corresponding to the remaining portions of the flow path forming portions 101 and 102, the flow path can be formed while leaving the horizontal dividing wall.

  At this time, in order to dispose the horizontal dividing wall in the center in the thickness direction of the substrate A, in the first etching step, erosion is performed to a depth corresponding to a predetermined dimension for the thickness of the horizontal dividing wall. In the next and third etching steps, erosion may be performed to a depth obtained by subtracting 1/2 of the planned thickness of the dividing wall from 1/2 of the thickness of the substrate A. Any etching process may be deep etching (DRIE) by reactive ion etching (RIE). In this case, assuming a difference in etching rate, the depth in the primary etching is made larger than the thickness of the horizontal dividing wall.

  Finally, a micromixer is formed by laminating plate-like members B and C on the upper and lower surfaces of the substrate A (see FIG. 1). The substrate B stacked on the upper surface is provided with supply ports 4 and 5 and a discharge port 6, which may be provided with through holes by mechanical means or by erosion. It is.

  Since the embodiment according to the manufacturing method has the above-described configuration, a fine flow path (flow path forming region) is configured by using semiconductor process technology, particularly deep etching technology, and in the middle of the flow path. A horizontal dividing wall and a vertical dividing wall can be configured. Furthermore, it is possible to configure a guide wall that continues between the flow paths divided by these divided walls.

  In the above manufacturing method, the lower surface is processed after processing the upper surface of the substrate A. However, the third film forming step for the lower surface is performed simultaneously with or after the first film forming step for the upper surface. As long as the film is formed in a predetermined range and then sequentially etched, the order can be changed. Also, in the third etching step, the processing may be started from the lower surface of the substrate A first after the third film forming step.

  Next, a fluid mixing state was tested using the micromixer having the configuration described in the above embodiment. The micromixer used in the experiment has a mixing part with a flow path of 500 μm and a depth of 300 μm. Each mixer part has a horizontal dividing wall with a thickness of 10 μm as shown in FIG. The vertical dividing wall has a distance of 225 μm from the left and right flow channel side walls (thickness is 50 μm), and the length from the horizontal dividing wall to the tip is 435 μm. Furthermore, as shown in FIG.7 (b), what provided the mixer part of the said structure 10 continuously was used. Regarding the guide wall, in the first mixer section, the upper guide wall has a right guide surface and the lower guide wall has a left guide surface, and in the second mixer section, the upper guide wall The left guide surface was provided, and the right guide surface was provided on the lower guide wall, and these were alternately arranged thereafter. In manufacturing the micromixer, a silicon substrate was used as the substrate, a silicon oxide film was formed in the first film formation step, and a photoresist material was used as a mask material in the second film formation step. In the etching process, erosion was performed by so-called deep etching.

  In addition, the conventional micromixer shown in FIG. 6 was manufactured as a comparative example. Since the conventional micromixer does not have a horizontal dividing wall, the other dimensions are the same as those of the experimental micromixer except for the dimensions related to the horizontal dividing wall. The manufacturing method such as the film forming process and the etching process is the same as that of the experimental micromixer.

[Experiment 1]
Two types of fluids were passed through the micromixer. One of the fluids used is ethanol containing a fluorescent dye (hereinafter referred to as a fluorescent solution), and the other is normal ethanol containing no fluorescent dye (hereinafter referred to as a normal solution). In the supply unit that supplies the fluid to the mixing unit, the fluorescent solution is supplied from the supply port (Inlet (see FIG. 7B)) on the left side in a plan view, and the right supply port (Inlet (see FIG. 7B)). The normal solution is supplied from. At that time, the fluorescence intensity was measured in a range from the right wall surface to the left wall surface in a plan view of the flow path. The measured points are immediately before the fluid flows into the first mixer section (Before mixing in the figure) and the time point when the fifth passage is passed (This work in the figure). Moreover, about the comparative example, only the time of passing the 5th was measured (Previous mixer in the figure). The above results are shown in FIG. FIG. 8 is a graph showing the fluorescence intensity in a range of a distance of 500 μm between a and b, where a is the right end in a plan view and b is the left end.

  As shown in FIG. 8, the fluorescence intensity immediately before flowing into the first mixer section is almost zero near the wall surface on the side where the normal liquid is flowing (in the range of 0 to 200 μm from the point a). On the contrary, the fluorescence intensity near the wall surface on the side into which the fluorescent liquid flows (in the range of 300 to 500 μm from point a) is extremely high. On the other hand, in the state where it passed through the fifth mixer section, the value of the fluorescence intensity was high throughout the channel, and it was found that the fluorescent solution was dispersed throughout the channel.

  In addition, according to the result of the comparative example of FIG. 8, although there is a part where the value of the fluorescence intensity in the vicinity of the wall surface on the normal liquid side (in the range of 0 to 200 μm from the point a) is slightly higher, it approaches the wall surface. In the range (the range from 0 to 100 μm from the point a), the state before the mixing was unchanged. From the difference from this comparative example, it was found that the mixing state by the micromixer of this example was very good.

  In the above experiment, the state in plan view of the flow path passing through the micromixer of this example was photographed with a fluorescence microscope. The photograph is shown in FIG. FIG. 9A is an image in the first mixer section, and FIG. 9B is an image in the fifth mixer section. As can be seen from this image, the fluid passing through the fifth fluid is mixed with the fluorescent liquid and the normal liquid so as to form a layer. In these images, a portion reflected in white is a portion having a strong fluorescence intensity, and a portion disappearing in black includes a portion where a fluid having a low fluorescence intensity exists. Also, at locations where a horizontal dividing wall exists, the point that passes through the lower flow path is black because the fluid cannot be seen in plan view, and the fluorescence value of the fluid that passes through the upper flow path decreases, so the fluorescence intensity greatly decreases. It is reflected in gray. In addition, the broken line in a figure supplements the end surface position of a flow path and a guide wall.

As shown in the result of Experiment 1 above, two types of fluids that have passed through a plurality of mixer sections form a layer, and this is because the upper and lower guide walls are on the right guide surface or left guide. It will be understood that the layer shape is similarly formed on any of the surfaces. Therefore, an optimum state for fluid mixing can be configured by appropriately changing the guide surface of the guide wall in consideration of the degree of molecular diffusion and the like.
[Experiment 2]
Next, an experiment similar to the above was performed by setting the ratio of the amount of the fluorescent solution and the amount of the normal solution to 1: 9. The experimental result is shown in FIG. 10, and the fluorescence micrograph is shown in FIG. From this result, as shown in FIG. 10, immediately before flowing into the first mixer section, the value of the fluorescence intensity is high only in the vicinity of the point b (range from 400 to 500 μm from the point a). After passing through the fifth mixer section, although there is a slight difference in the fluorescence intensity, the fluorescence intensity is sufficiently high even near the point a. Further, as shown in FIG. 11, it was found that the same layer shape as in Experiment 1 was formed even when the supply ratio of the fluid was different.

  From the above results, it is possible to mix fluids with different supply amounts, and to mix them while adjusting the concentration. Therefore, in addition to the fluid mixing method in which the concentration is lowered step by step while supplying the same amount of fluid, by changing the supply amount of the fluid to be mixed, the mixed fluid of the desired concentration is passed once. It is possible to adjust by.

  As described above, for Experiment 1 and Experiment 2, the upper base after passing through the fifth mixer section is evaluated, but when 10 mixer sections are made continuous as described in the experimental apparatus. The mixed state of the fluid after passing through the tenth mixer section can be more suitable than the above result.

DESCRIPTION OF SYMBOLS 1 Supply part formation area 2 Mixing part formation area 3 Discharge part formation area 4,5 Supply port 6 Discharge port 7,8 Mixer part separate area | region 11,12 Branch flow path formation part 13 Combined flow path formation part 21 Mixer part formation area 22, 23 flow path forming area 31 flow path forming area 71 horizontal dividing wall (first dividing wall)
72 Vertical dividing wall (second dividing wall)
73 Upper guide wall (first guide wall)
74 Lower guide wall (second guide wall)
75, 76 Guide surfaces 81a, 82a Both-side flow path components 81b, 82b on the upper surface Flow path both-end components 83a on the lower surface Upper end surface 83b of the vertical dividing wall (second dividing wall) Vertical dividing wall (second dividing wall) Lower end surface 84a of the upper wall (first guide wall) Upper end surface 85b of the lower guide wall (second guide wall) Lower end surface 91 of the upper guide wall (first guide wall) Surface portion on which the horizontal dividing wall (first divided wall) is formed 92 Upper surface portion 93 of horizontal dividing wall (first dividing wall) 93 Lower surface portions 101, 102 of horizontal dividing wall (first dividing wall) A part where flow paths are formed A Substrate B, C Plate member

Claims (6)

A micromixer comprising: a supply unit that supplies a plurality of fluids; a mixing unit that mixes a plurality of fluids supplied from the supply unit; and a discharge unit that discharges the fluid after mixing.
The mixing unit includes a plurality of continuous mixer units, and each mixer unit includes a first dividing wall that divides the entire channel into an upper channel and a lower channel, and a downstream side of the first dividing wall. A second dividing wall that divides the entire channel into a left channel and a right channel, a first guide wall that guides the upper channel to one of the left and right channels, and the lower part A micromixer comprising: a second guide wall that guides the channel to the other of the left and right channels. The mixing unit includes a first mixer unit in which the upper channel is guided to the right channel and the lower channel is guided to the left channel, and the upper channel is guided to the left channel. The micromixer according to claim 1, wherein the lower channel is a mixing unit in which a second mixer unit guided by the right channel is mixed. The micromixer according to claim 2, wherein the mixing unit is a mixing unit in which the first mixer unit and the second mixer unit are alternately arranged. A method for producing the micromixer according to any one of claims 1 to 3,
A flow path forming step of forming a flow path at an appropriate position of a substrate having a predetermined thickness, and a laminating step of laminating plate members on the upper surface and the lower surface of the substrate,
The flow path forming step includes a surface excluding a range where the supply unit, the mixing unit, and the discharge unit are formed on the upper surface of the substrate, and a second dividing wall and a first guide wall of the mixer unit. A first film forming step of forming a film on the surface of the portion to be formed;
A second film-forming step of forming a film on the surface of the film formed by the first film-forming step and the surface on which the first dividing wall is formed;
A primary etching step of etching from an upper surface of the substrate;
Removing the film formed in the second film formation step;
A second etching step of etching from the upper surface of the substrate;
A third film is formed on the surface of the lower surface of the substrate excluding the range where the supply unit, the mixing unit and the discharge unit are formed, and on the surface of the portion where the second dividing wall of the mixer unit is formed. The next film-forming step;
A micromixer manufacturing method comprising: an erosion step including a third etching step of etching from a lower surface of the substrate. 5. The micromixer according to claim 4, wherein the substrate is a silicon substrate, and the first film formation step and the third film formation step are film formation steps for forming a silicon oxide film. Production method. Each of the etching steps is based on reactive ion etching (RIE), and the first etching step is etching that erodes to a depth larger than a dimension corresponding to the thickness of the first dividing wall to be manufactured. The second and third etching steps are etching steps that erode to a depth that is a size obtained by subtracting 1/2 of the dividing wall from 1/2 of the thickness of the substrate. The manufacturing method of the micromixer of Claim 4 characterized by the above-mentioned.