JPH04337170A - Microvalve - Google Patents

Abstract

PURPOSE:To prevent leakage of fluid and to simplify regulation of a valve opening pressure by removing a sacrifice layer after the sacrifice layer, a stress film, and a valve film are formed on the upper part of a base sheet. CONSTITUTION:An SiO2 film is formed on a base sheet 21 of a monocrystal or multicrystal Si by thermal oxidation and spattering, and etching is applied thereto, for example, in an HF solution, to form the shape of a sacrifice layer 31. Vapor phase growth of a nitride, such as Si3N4, is conducted by CVD and the nitride is etched into the shape of a valve stress film 32 shape. Vapor phase growth of a monocrystal Si film is conducted by CVD, etching is effected by using an etching solution, such as a KOH solution, to form a valve film 32, and thereafter the sacrifice layer 31 is removed by using a HF solution. Or further, after the base sheet 21 of a microvalve is separated away from a valve film 33, positive electrode joining is performed on a flow passage base sheet in which a through-hole is formed.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microvalve for controlling the flow rate of fluid, and more particularly to a method for manufacturing a microvalve using thin film forming technology.

0002

2. Description of the Related Art Conventionally, microvalves using thin film formation technology have been manufactured by Nikkei Electronics No. 480 (1989
Published on August 21, 2016) p. As reported in the special feature entitled "Silicon Micromachining Technology" in 125-155, a valve film made of a sacrificial layer was anodically bonded onto a substrate. Figure 2 shows a conventional microvalve. FIG. 2(a) is a sectional view of the valve. 21 is a valve membrane, and 22 is a substrate. 21
was formed using a surface micromachining technique using a sacrificial layer, and 21 and 22 were joined by anodic bonding. FIG. 2(b) is a front view.

0003

However, since there is a gap between the protrusion 23 of the valve membrane 21 and the substrate 22, there is a problem in that fluid leaks under normal conditions. Another disadvantage is that the valve opening pressure cannot be increased because the valve opening pressure can only be controlled by the size and thickness of the valve.

0004

[Means for Solving the Problems] The microvalve of the present invention for solving the above-mentioned problems has a sacrificial layer, a stress film that applies stress to the bulb, and the above-mentioned valve thin film formed on the upper part of the substrate, and the sacrificial layer It is characterized by being created by removing.

[0005] The above-mentioned microvalve is characterized in that after the substrate and the valve film are separated, the microvalve is bonded to a channel substrate in which through-holes are formed.

[0006]

[Embodiment] An embodiment of the present invention is shown in FIG. 1 below. Figure 1
2(a) shows a sectional view, and FIG. 2(b) shows a front view. 2
1 is a valve membrane, 22 is a substrate, 23 is a stress membrane that applies stress to the valve, 24 is a valve protrusion, and 25 is a fluid input part. The valve protrusion 24 is bent by stress in the direction of the substrate due to the valve stress film 23. The valve protrusion 24 then contacts the substrate 22 and applies a certain stress to the substrate 22. In other words, a certain preload is applied to the valve membrane 23.

FIGS. 3(a) to 3(d) show a method of manufacturing a microvalve according to the present invention. In FIG. 3A, a SiO2 film is formed on a substrate 21 by thermal oxidation, sputtering, etc., and etched in, for example, an HF solution to obtain the shape of a sacrificial layer 31. In the case of the SiO2 film 31, patterning,
The desired shape can be obtained by performing the etching process twice. Board 2
The material of 1 is generally single crystal, polycrystalline Si, or the like. In FIG. 3B, a nitride such as Si3N4 is grown in a vapor phase by CVD, and the nitride is etched into the shape of the valve stress film 32. In FIG. As an etching solution, H3PO
4 is common. In Figure 3(c), single crystal Si
The film is grown in a vapor phase by CVD and etched using an etching solution such as a KOH solution to obtain the shape of the valve film 33. In FIG. 3(d), the sacrificial layer 31 is removed using an HF solution. Then, the valve film 33 becomes the stress film 32
Due to the difference in internal stress, a moment is applied in the direction of the substrate 21, and the valve protrusion 34 comes into contact with the substrate 21 and is pressed down, thereby preventing fluid leakage.

FIG. 4 shows an embodiment of claim 2. FIG. 4(a) shows a microvalve made using the same process as FIG. 3. 41 is a SiO2 film formed on the top of the glass substrate, 42 is a bulb film made of single crystal Si, 43 is a stress film, and the bulb protrusion 44 is also covered with the stress film 43. When the sacrificial layer is etched using an HF solution, a microvalve having a shape as shown in FIG. 4(b) is obtained. Next, in FIG. 4(c), a glass substrate 45 provided with a through hole 46 through which a fluid passes and a glass substrate 45 shown in FIG.
The structure in (b) is anodically bonded. Then, the valve membrane 42
The peripheral portion of the bulb is bonded to the glass substrate 41, but the bulb protrusion 44 is not bonded because the stress film 43 covers the protrusion. In this case, if the nitride of the stress film 43 is used,
It has been confirmed that bonding does not occur even when the thickness is about 0.1 μm.

[0009] As for the material of the microvalve of the present invention, the substrate 21 can be made of various materials such as glass, single crystal Si, and polycrystalline Si. Aluminum, also used as a valve membrane.
Ni et al. Various materials such as ZnO, Au, and Cr can be considered as the stress film.

As for the structure of the valve, a so-called cantilever structure micro valve is also considered.

[0011]

[Effects of the Invention] As described above, according to the microvalve of the present invention, surface micromachining technology is used to
By forming a valve film using stress, it becomes possible to form a micron-order valve that does not leak fluid. For example, the diameter of the bulb is 20 μm and the thickness is 2 μm.
In this microvalve, the diameter of the stress film is 12 μm,
If the thickness is 1 μm, it is possible to construct a microvalve that does not cause fluid leakage even if fluid is applied in the input direction of the valve at a pressure of 1 mH2O. Further, by changing the thickness of the stress film, the valve opening pressure can be easily adjusted.

As described in FIG. 3, since the substrate and the valve can be manufactured as one unit, it is difficult for dust and contaminants to enter the valve protrusion and flow path, making it possible to manufacture the valve with high precision. .

[0013] By making it possible to make such a small microvalve, it becomes possible to make a small micropump.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view (a) and a front view (b) of a microvalve of the present invention.

FIG. 2 is a sectional view (a) of a conventional microvalve;
It is a front view (b).

FIGS. 3(a) to 3(d) are diagrams showing the manufacturing process of the microvalve of the present invention.

FIGS. 4(a) to 4(c) are diagrams showing the manufacturing process of the microvalve according to claim 2 of the present invention.

[Explanation of symbols]

1 Valve membrane 2 Board 3 Stress film 4 Valve protrusion 5 Flow path section

Claims (2)

[Claims] 1. In a microvalve composed of a substrate and a valve thin film, a sacrificial layer, a stress film that applies stress to the valve, and the valve thin film are formed on the top of the substrate to control the flow rate of a fluid. A microvalve characterized by being made by removing a layer. 2. The microvalve described above, wherein after the substrate and the valve film are separated, the microvalve is bonded to a channel substrate in which a through hole is formed.