JP2006181489A - Method for manufacturing small-sized reactor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make glass substrates connectable by anodes in a small-sized reactor provided with an anode connection structure of the glass substrates. <P>SOLUTION: An anode plate 27 connected to first and second glass substrates 1, 5, and the anode of a direct current source 24 through a switch 26 is placed on a cathode plate 25 connected to the cathode of the direct current source 24. In this case, a catalyst carrier film 4 comprising a porous metal oxide film is formed by a spraying method in a flow passage 2 formed on the upper surface of the first glass substrate 1, and a metal film 3 for anode connection is formed on the upper surface of the first glass substrate 1 in a region other than a region corresponding to the flow passage 2. As a result, when the catalyst carrier film 4 comprising the porous metal oxide film is formed by a spraying method, the metal film 3 for anode connection is not oxidized, and when the anode connection is performed, the first glass substrate 1 and the second glass substrate 5 are connected by an anode through the metal film 3 for anode connection. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for manufacturing a small reactor.

  In the technical field of chemical reaction, there is known a small-sized reaction apparatus that generates a desired fluid substance by a chemical reaction (catalytic reaction) by a catalyst provided in a flow path of a fluidized mixed substance. In such a conventional small reaction apparatus, a micron-order or millimeter-order flow path is formed on one surface of a silicon substrate by using microfabrication technology accumulated in semiconductor manufacturing technology such as a semiconductor integrated circuit. There is one in which a glass substrate for covering a flow path on one surface is anodically bonded (for example, see Patent Document 1).

JP 10-337173 A

  By the way, although it is possible to use a glass substrate instead of a silicon substrate and anodically bond glass substrates together, direct anodic bonding cannot be performed between glass substrates. Therefore, when a metal film for anodic bonding that can be bonded to the other glass substrate by being oxidized by anodic bonding is formed on one surface of one glass substrate, the glass substrates are bonded to each other through the anodic bonding metal film. Can be joined.

  By the way, in a flow path formed on one surface of one glass substrate, a previously formed aluminum film is anodized to form a catalyst supporting film made of a porous aluminum oxide film, and this porous catalyst supporting film In some cases, a larger amount of catalyst may be supported. In such a case, if the anodic oxidation treatment is performed with the anodic bonding metal film formed on one surface of one glass substrate, the anodic bonding metal film is also oxidized at the same time. It becomes impossible to do.

  Accordingly, the present invention provides a method for manufacturing a small reactor capable of anodic bonding of glass substrates even when a porous catalyst-supporting film is formed in a flow path formed on one surface of one glass substrate. The purpose is to provide.

  In order to achieve the above object, the present invention provides a metal oxide film formed by a thermal spraying method in a channel formed on one surface of a first glass substrate where a bonding metal film is provided in a region other than a channel forming region. And a step of bonding a second glass substrate to the one surface of the first glass substrate via the bonding metal film. .

  According to the present invention, since the catalyst supporting film made of the metal oxide film is formed by the thermal spraying method in the flow path formed on one surface of the first glass substrate, the catalyst supporting film is formed by the thermal spraying method. The bonding metal film formed on one surface of the first glass substrate is not oxidized. Therefore, even if the catalyst supporting film is formed in the flow path formed on one surface of the first glass substrate, Glass substrates can be joined together.

  FIG. 1 shows a transmission plan view of a small reactor manufactured by the manufacturing method as one embodiment of the present invention, and FIG. 2 shows a cross-sectional view taken along line II-II in FIG. This small reactor includes a first glass substrate 1 having a small rectangular shape. On the upper surface of the first glass substrate 1, there is formed a flow path 2 that becomes a part of a meandering minute reaction furnace by a sandblast method or the like. The dimensions of the flow path 2 are, for example, a width of about 0.2 to 0.8 mm, a depth of about 0.2 to 0.6 mm, and a total length of about 30 to 1000 mm.

  A metal film 3 for anodic bonding is provided in a region other than the flow path 2 on the upper surface of the first glass substrate 1. A specific material of the anodic bonding metal film 3 will be described later. On the inner wall surface of the flow path 2 including the inner wall surface of the opening corresponding to the flow path 2 of the metal film 3 for anodic bonding, a catalyst supporting film 4 made of a porous metal oxide film formed by a thermal spraying method is provided. It has been. Specific materials for the catalyst support film 4 will be described later. A catalyst (not shown) is supported on the porous catalyst support film 4. Specific materials for the catalyst will be described later.

  On the upper surface of the anodic bonding metal film 3 on the first glass substrate 1, a second glass substrate 5 having the same size as the first glass substrate 1 is anodic bonded as described later. That is, the second glass substrate 5 is anodically bonded to the upper surface of the first glass substrate 1 via the anodic bonding metal film 3. An inlet 6 and an outlet 7 are provided at two predetermined locations corresponding to both ends of the flow path 2 of the second glass substrate 5.

  An insulating film 8 made of silicon nitride or the like is provided on the entire lower surface of the first glass substrate 1. A solid thin film heater 9 made of a metal film such as Au or a resistor film such as Ta—Si—O is provided on the entire lower surface of the insulating film 8. The thin film heater 9 is used for supplying predetermined thermal energy to the catalyst supporting film 4 in the flow path 2 at the time of chemical reaction when the chemical reaction (catalytic reaction) in this small reactor involves an endothermic reaction under a predetermined thermal condition. Is.

  Wirings 10 and 11 having a three-layer structure including a Ti—W layer, an Au layer, and a Ti—W layer are provided at both ends of the lower surface of the thin film heater 9. The thin film heater 9 generates heat when a voltage is applied to these wirings 10 and 11.

  Next, an example of the manufacturing method of this small reactor will be described. First, as shown in FIG. 3, an insulating film 8 made of silicon nitride is formed on the lower surface of the first glass substrate 1 by plasma CVD or the like. Next, a metal film such as Au or a resistor film such as Ta—Si—O is formed on the lower surface of the insulating film 8 by sputtering or the like to form a solid thin film heater 9. Next, a wiring forming film having a three-layer structure including a Ti—W layer, an Au layer, and a Ti—W layer formed by sputtering or the like is patterned on both ends of the lower surface of the thin film heater 9 by photolithography. Thus, the wirings 10 and 11 are formed.

  Next, as shown in FIG. 4, Ta, W, Ti, etc. that can be bonded to the second glass substrate 5 by being oxidized by anodic bonding on the upper surface of the first glass substrate 1 by sputtering or the like. A metal film forming film 21 for anodic bonding made of is formed. Next, on the upper surface of the metal film forming film 21 for anodic bonding, a resist film 22 is formed by patterning the laminated dry film photoresist in a region other than the region corresponding to the flow path 2 by photolithography. To do.

  Next, when unnecessary portions of the anodic bonding metal film forming film 21 are removed by etching using the resist film 22 as a mask, the anodic bonding metal film 3 is formed under the resist film 22 as shown in FIG. The Next, when processing such as sandblasting using the resist film 22 as a mask is performed, as shown in FIG. 6, the minute flow path 2 meandering on the upper surface of the first glass substrate 1 in a region other than the region under the resist film 22. Is formed.

Next, as shown in FIG. 7, a porous metal oxide film forming film 23 is formed on the surface of the resist film 22 including the inner wall surface of the flow path 2 by a thermal spraying method. As a material of the metal oxide film forming film 23, metal oxides such as Al ₂ O ₃ and Al ₂ O ₃ SiO ₂ which are hardly affected by chemical reaction performed in a small reactor and which are components of glass are used. Is preferred. The thermal spraying method includes plasma spraying method, arc spraying method, gas flame spraying method, ultra-high speed flame spraying method, and the like. In this method, a porous metal oxide film forming film 23 is formed.

  As described above, since the porous metal oxide film forming film 23 is formed by the spraying method in the flow path 2 formed on the upper surface of the first glass substrate 1, the metal oxide film is formed by the spraying method. When the working film 23 is formed, the anodic bonding metal film 3 formed on the upper surface of the first glass substrate 1 is not oxidized, and therefore the flow path 2 formed on the upper surface of the first glass substrate 1. Even if the porous metal oxide film forming film 23 is formed therein, the glass substrates 1 and 5 can be anodically bonded as described later.

  Next, although not shown, an active metal species (specific materials will be described later) serving as a catalyst is adsorbed on the porous metal oxide film forming film 23. The active metal species can be adsorbed by spraying a metal salt aqueous solution onto the metal oxide film forming film 23 or by spraying an aqueous solution containing other metal particles or metal oxide particles. There are methods for adsorbing various types of active metal species. Next, heat treatment is performed, and the catalyst is fired and fixed to the porous metal oxide film forming film 23.

  Next, when the resist film 22 is peeled off together with the metal oxide film forming film 23 formed on the surface thereof by the lift-off method, the opening corresponding to the flow path 2 of the metal film 3 for anodic bonding as shown in FIG. A porous catalyst-carrying film 4 carrying a catalyst is formed on the inner wall surface of the flow path 2 including the inner wall surface.

  Next, as shown in FIG. 9, the wirings 10 and 11 provided on the lower surface of the first glass substrate 1 are positioned and placed on the cathode plate 25 connected to the cathode of the DC power supply 24. Next, the second glass substrate 5 having the inlet 6 and the outlet 7 provided on the upper surface of the first glass substrate 2 is positioned and placed on the anodic bonding metal film 3. Next, an anode plate 27 connected to the anode of the DC power supply 24 via the switch 26 is placed on the second glass substrate 5.

  Next, in a state where the first and second glass substrates 1 and 5 are heated to 400 to 600 ° C., the switch 26 is closed, and a DC voltage of about 1 kV is applied from the DC power source 24 to the bipolar plates 25 and 27. Then, cations that are impurities in the second glass substrate 5 move away from the anodic bonding metal film 3, and the concentration of oxygen ions at the interface of the second glass substrate 5 on the anodic bonding metal film 3 side. A high layer appears. Then, the metal atom at the interface on the second glass substrate 5 side of the anodic bonding metal film 3 and the oxygen ion at the interface on the anodic bonding metal film 3 side of the second glass substrate 5 are combined to form a strong bonding interface. Is obtained.

  The first glass substrate 1 and the second glass substrate 5 are firmly bonded through the anode bonding metal film 3 having a strong bonding interface. In this case, the first and second glass substrates 1 and 5 are heated to 400 to 600 ° C. and a DC voltage of about 1 kV is applied between the bipolar plates 25 and 27 because the impurities in the second glass substrate 5 This is to increase the speed at which the cation moves in a direction away from the anode bonding metal film 3.

By the way, in the above manufacturing method, the same resist film 22 is used to form the anodic bonding metal film 3, the flow path 2, and the catalyst supporting film 4, so that the number of manufacturing steps can be reduced. Further, if the metal film 3 for anodic bonding is formed of a metal oxide such as Al ₂ O ₃ or Al ₂ O ₃ SiO ₂ which is a glass component, it is a thin film compared to a case where it is formed of a material different from the glass component. The heat transfer efficiency from the heater 9 to the anodic bonding metal film 3 through the first glass substrate 1 can be improved.

  Further, in the above manufacturing method, the anodic bonding metal film 3 is used for the anodic bonding, but instead of the anodic bonding metal film 3, a relatively easy to oxidize bonding metal film is used for techniques other than anodic bonding. The same effect can be brought about also when joining.

  Next, a description will be given of a case where the small reactor configured as described above is applied to a fuel cell system using a fuel reforming type fuel cell. FIG. 10 shows a block diagram of a main part of an example of the fuel cell system 31. The fuel cell system 31 includes a fuel unit 32, a fuel vaporization unit 33, a reforming unit 34, a carbon monoxide removal unit 35, a power generation unit 36, a charging unit 37, and the like.

The fuel unit 32 includes a fuel pack in which a fuel for power generation (for example, methanol aqueous solution (CH ₃ OH + H ₂ O)) is sealed, and supplies the power generation fuel to the fuel vaporization unit 33 by driving a pump (not shown).

The fuel vaporization part 33 has a structure as shown in FIGS. 1 and 2, for example. However, in this case, the catalyst supporting film 4 is not provided in the flow path 2. Then, when the fuel for power generation from the fuel unit 32 is supplied into the flow path 2 through the inlet 6, the fuel vaporization section 33 is heated by the thin film heater 9 (about 120 ° C.) in the flow path 2. Then, the power generation fuel is vaporized, and the vaporized power generation fuel gas (for example, CH ₃ OH + H ₂ O when the power generation fuel is an aqueous methanol solution) is caused to flow out from the outlet 7.

The power generation fuel gas (CH ₃ OH + H ₂ O) vaporized by the fuel vaporization unit 33 is supplied to the reforming unit 34. In this case, the reforming part 34 also has a structure as shown in FIGS. However, in this case, a catalyst supporting film 4 is provided in the flow path 2 of the first glass substrate 1, and a reforming catalyst such as Cu, ZnO, Al ₂ O ₃ is supported on the catalyst supporting film 4, for example. Has been. Then, when the reforming unit 34 is supplied with the power generation fuel gas (CH ₃ OH + H ₂ O) from the fuel vaporization unit 33 into the flow path 2 through the inflow port 6, the thin film heater is formed in the flow path 2. 9 (about 280 ° C.) causes an endothermic reaction as shown in the following formula (1) to generate hydrogen and carbon dioxide as a by-product.
CH ₃ OH + H ₂ O → 3H ₂ + CO ₂ (1)

The water (H ₂ O) on the left side of the above formula (1) may be contained in the fuel of the fuel unit 32 at the initial stage of the reaction, but the water generated with the power generation of the power generation unit 36 to be described later. It may be recovered and supplied to the reforming unit 34. Further, the water (H ₂ O) supply source on the left side of the above formula (1) during power generation by the power generation unit 36 may be only the power generation unit 36, the power generation unit 36 and the fuel unit 32, or only the fuel unit 32. But you can. At this time, although it is a small amount, carbon monoxide may be generated in the reforming unit 34.

  Then, the product (hydrogen, carbon dioxide) and a small amount of carbon monoxide on the right side of the formula (1) flow out from the outlet 7 of the reforming unit 34. Among the products flowing out from the outlet 7 of the reforming unit 34, vaporized hydrogen and carbon monoxide are supplied to the carbon monoxide removing unit 35, and carbon dioxide is separated and released into the atmosphere.

Next, the carbon monoxide removal part 35 also has a structure as shown in FIGS. However, in this case, a catalyst supporting film 4 is provided in the flow path 2 of the first glass substrate 1, and a selective oxidation catalyst such as Pt and Al ₂ O ₃ is supported on the catalyst supporting film 4, for example. Yes. The carbon monoxide removal unit 35 heats the thin film heater 9 (about 180 ° C.) when the vaporized hydrogen and carbon monoxide from the reforming unit 34 are supplied into the flow path 2 through the inlet 6. ), Hydrogen monoxide and water out of hydrogen, carbon monoxide, and water supplied into the flow path 2 react with each other. As shown in the following equation (2), hydrogen and carbon dioxide as a by-product And are generated.
CO + H ₂ O → H ₂ + CO ₂ (2)

The water (H ₂ O) on the left side of the above formula (2) may be contained in the fuel of the fuel unit 32 at the initial stage of the reaction, but the water generated by the power generation of the power generation unit 36 is recovered. The carbon monoxide removal unit 35 can be supplied. Further, the water supply source on the left side of the reaction formula (2) in the carbon monoxide removal unit 35 may be only the power generation unit 36, the power generation unit 36 and the fuel unit 32, or only the fuel unit 32.

And most of the fluid finally reaching the outlet 7 of the carbon monoxide removal section 35 is hydrogen and carbon dioxide. In addition, when a trace amount of carbon monoxide is contained in the fluid reaching the outlet 7 of the carbon monoxide removal unit 35, the remaining carbon monoxide is converted into oxygen taken in from the atmosphere via a check valve. By contacting, carbon dioxide is generated as shown in the following formula (3), and thereby carbon monoxide is surely removed.
CO + (1/2) O ₂ → CO ₂ (3)

  The product after the series of reactions is composed of hydrogen and carbon dioxide (including a trace amount of water in some cases). Among these products, carbon dioxide is separated from hydrogen and released into the atmosphere. Accordingly, only hydrogen is supplied from the carbon monoxide removal unit 35 to the power generation unit 36. Note that the carbon monoxide removal unit 35 may be provided between the fuel vaporization unit 33 and the reforming unit 34.

  Next, as shown in FIG. 11, the power generation unit 36 includes a known solid polymer fuel cell. That is, the power generation unit 36 includes a cathode 41 made of a carbon electrode to which a catalyst such as Pt and C is attached, an anode 42 made of a carbon electrode to which a catalyst such as Pt, Ru and C is attached, and a cathode 41 and an anode 42. A film-like ion conductive film 43 interposed between and a power supply to a charging unit 37 including a secondary battery or a capacitor provided between the cathode 41 and the anode 42. To do.

  In this case, a space 44 is provided outside the cathode 41. Hydrogen is supplied from the carbon monoxide removing unit 35 into the space 44 and hydrogen is supplied to the cathode 41. A space 45 is provided outside the anode 42. Oxygen taken in from the atmosphere through the check valve is supplied into the space 45, and the anode 42 oxygen is supplied.

On the cathode 41 side, as shown in the following formula (4), hydrogen ions (protons; H ⁺ ) in which electrons (e ⁻ ) are separated from hydrogen are generated, and the anode 42 side via the ion conductive film 43 is generated. The electrons (e ⁻ ) are taken out by the cathode 41 and supplied to the charging unit 37.
_{^{3H 2 → 6H + + 6e -}} ...... (4)

On the other hand, on the anode 42 side, as shown in the following formula (5), electrons (e ⁻ ) supplied via the charging unit 37, hydrogen ions (H ⁺ ) that have passed through the ion conductive film 43, oxygen, React to produce by-product water.
6H ⁺ + (3/2) O ₂ + 6e ⁻ → 3H ₂ O (5)

  The series of electrochemical reactions as described above (formula (4) and formula (5)) proceed in a relatively low temperature environment of about room temperature to about 80 ° C., and by-products other than electric power are basically water. It becomes only. The electric power generated by the power generation unit 36 is supplied to the charging unit 37, whereby the charging unit 37 is charged.

  Water as a by-product generated in the power generation unit 36 is recovered. In this case, as described above, when at least a part of the water generated by the power generation unit 36 is supplied to the reforming unit 34 and the carbon monoxide removal unit 35, the amount of water initially sealed in the fuel unit 32. And the amount of recovered water can be reduced.

  By the way, the fuel applied to the fuel cell of the fuel reforming method currently being researched and developed is at least a liquid fuel, a liquefied fuel or a gaseous fuel containing hydrogen element, Any fuel can be used as long as it can generate electric energy with a relatively high energy conversion efficiency. In addition to the above methanol, alcohol-based liquid fuels such as ethanol and butanol, dimethyl ether, isobutane, and natural gas (CNG) It is possible to satisfactorily apply a fluid substance such as a liquid fuel made of hydrocarbons vaporized at normal temperature and pressure, such as a liquefied gas, or a gaseous fuel such as hydrogen gas.

The permeation | transmission top view of the small reactor as one Embodiment of this invention. Sectional drawing which follows the II-II line | wire of FIG. FIG. 3 is a cross-sectional view of an initial process in manufacturing the small reactor shown in FIGS. 1 and 2. Sectional drawing of the process following FIG. Sectional drawing of the process following FIG. Sectional drawing of the process following FIG. Sectional drawing of the process following FIG. Sectional drawing of the process following FIG. FIG. 9 is a cross-sectional view of the process following FIG. 8. The block diagram of the principal part of an example of the fuel cell system provided with the small reactor. The schematic block diagram of the electric power generation part and charging part of the fuel cell system shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 1st glass substrate 2 Flow path 3 Metal film for anodic bonding 4 Catalyst support film 5 2nd glass substrate 6 Inlet 7 Outlet 8 Insulating film 9 Thin film heater 10, 11 Wiring 24 DC power supply 25 Cathode plate 26 Switch 27 Anode plate

Claims (7)

A step of forming a catalyst-supporting film made of a metal oxide film by a thermal spraying method in a flow path formed on one surface of the first glass substrate other than the flow path forming area provided with a bonding metal film;
Bonding a second glass substrate to the one surface of the first glass substrate via the bonding metal film;
The manufacturing method of the small reactor characterized by including.   The method according to claim 1, wherein the flow path is formed on the one surface of the first glass substrate after the bonding metal film is formed.   In the invention according to claim 2, the bonding metal film is formed by etching the formed bonding metal film forming film using a resist film formed thereon as a mask, A method for manufacturing a small-sized reaction apparatus, which is formed by a process using a resist film as a mask.   4. The method for manufacturing a small reactor according to claim 3, wherein the treatment for forming the flow path is a sandblasting method.   In the invention according to claim 3, the catalyst-carrying film is formed on the surface of the resist film of the catalyst-carrying film-forming film formed with the resist film remaining after the flow path is formed. A method for producing a small reactor, wherein the formed catalyst-supporting film-forming film is peeled off together with the resist film.   2. The method of manufacturing a small reactor according to claim 1, further comprising a step of forming a thin film heater on the other surface opposite to the one surface of the first glass substrate. 7. The method for manufacturing a small reactor according to claim 6, wherein the metal film for bonding is formed after the thin film heater is formed.

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