JPH11257231A - Micro-pump and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high tightly closed performance, thin a micro-pump, and supply liquid in both directions by holding a packing between a substrate part and a top plate part. SOLUTION: For example, two valve diaphragms 6 and one pumping diaphragm 7 are formed on a silicon substrate by means of etching, piezoelectric elements are installed on each diaphragm 6, 7 so as to constitute an uni-morph actuator. The silicon substrate 1 is joined with a glass substrate 2 having a penetrating hole 5, and a packing 4 is held between the valve diaphragm 6 and the glass substrate 2. Since the uni-morph actuator is used, a very thin micro-pump is manufactured, and liquid is supplied in both directions since an active valve is used. Since the packing 4 is held between the glass substrate 2 and the valve diaphragm 6, the micro-pump having a high pressure proof property and having a high liquid supplying efficiency is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure and a manufacturing method of a micropump and a microvalve in a medical field, an analysis field, and the like where it is essential to send a minute amount of liquid with high precision and to downsize the apparatus itself.

[0002]

2. Description of the Related Art As a conventional micropump applied in the medical field, the analysis field, etc., for example, Japanese Patent Application Laid-Open No.
There is a thing described in 164052 public information. According to the present invention, as shown in FIG. 2, a fixed laminated piezoelectric actuator having a liquid suction / discharge member 21 adhered to an end surface thereof inside a casing ring 26, and two laminated piezoelectric actuators having a valve 23 adhered to an end surface thereof. The actuator 22 includes an actuator 22, and has a structure in which the three actuators drive liquid through the flow path port 24 and the pump chamber 25.

In the case of a micropump described in Japanese Patent Application Laid-Open No. 5-1669, a thin film 32 of metal or polysilicon is formed on a sacrificial layer of an oxide film on a silicon substrate 31 as shown in FIG. The sacrifice layer is further removed by etching to form a metal or polysilicon check valve, and the piezoelectric element 3 provided on the glass substrate 33 is formed.
4 is characterized by constituting a pump.

In the case of the invention described in Japanese Patent Laid-Open Publication No. Hei 5-263766, two bimorph type piezoelectric elements 42 for driving two pumps are provided above and below a pump chamber 41 as shown in FIG.
Are attached, and a valve body 4 is provided at the suction port and the discharge port.
A flow control valve 45 composed of a piezoelectric element 3 and a bimorph type piezoelectric element 44 is attached, and the driving of the pump piezoelectric element 42 and the fluid control valve piezoelectric element 44 can be controlled by the same controller 46.

[0005]

In the case where an active valve is manufactured by using a laminated piezoelectric element as shown in FIG. 2 as an actuator, the thickness of the laminated piezoelectric element itself cannot be reduced because of the thickness of the laminated piezoelectric element itself. There was a problem that was possible. Further, in a micropump having two check valves as shown in FIG. 3, since liquid transfer is realized by using a passive check valve, liquid can be transferred only in one direction due to its structure. Had problems.

When a valve is used as a valve by directly closing a flow path with a bimorph type actuator of a piezoelectric element as shown in FIG. 4, the actuator must be protected because a fluid touches the actuator. Had. Therefore, in the present invention, a unimorph actuator is used so that the diaphragm of the substrate section can obtain a sufficient displacement, and a structure in which packing such as silicone rubber is sandwiched between the substrate section and the top plate section is used. An object of the present invention is to realize a micropump that achieves hermeticity, enables thinning and bidirectional liquid transfer, and has high pressure resistance and discharge efficiency.

[0007]

According to the present invention, a high sealing property is realized in a valve portion by using a structure in which packing such as silicone rubber is sandwiched between a diaphragm on a substrate and a top plate. Furthermore, a unimorph actuator in which a piezoelectric element is attached to the diaphragm is configured to realize a structure in which a fluid flows between the packing and the diaphragm or between the packing and the top plate, thereby realizing an active microvalve.

[0008] The two micro-valves are connected to a pumping section by a piezoelectric element and a diaphragm by a flow path.
By driving each actuator, liquid is supplied, and a micropump that is thin, has high pressure resistance and high discharge efficiency, and is capable of bidirectional liquid supply is realized.

[0009]

FIG. 1 shows the structure of a micropump according to the present invention. FIG. 1 (1-a) is a plan view of the micropump, and FIG. 1 (1-b) is a cross-sectional view of the micropump. The two valve diaphragms 6 and the one pumping diaphragm 7 are formed on the silicon substrate 1 by etching, and a piezoelectric element 3 is attached to each of the diaphragms to constitute a unimorph actuator. The silicon substrate 1 is bonded to a glass substrate 2 having a through-hole 5, and the packing 4 has a structure sandwiched between a valve diaphragm 6 and the glass substrate 2. By making the thickness of the packing higher than the etching depth of the diaphragm, the valve can be normally closed due to the rigidity of the diaphragm and the packing (FIG. 5).

In this state, by bending the unimorph actuator downward, the glass substrate and the packing,
Alternatively, a space is formed between the packing and the valve diaphragm, and a fluid flows through this space to realize an open state of the valve. In addition, by using a unimorph actuator and bending the pumping diaphragm upward, liquid ejection can be realized.

[0011] Liquid supply is realized by opening and closing the two microvalves and driving the pumping diaphragm in order. Hereinafter, embodiments of the present invention will be described with reference to the drawings. Example 1 First, a 0.3 μm oxide film 8 is formed on a silicon substrate 1 as shown in FIG. 6 (6-a) by thermal oxidation as shown in FIG. 6 (6-b). Subsequently, resist patterning is performed on the surface, and a part of the oxide film 8 is removed by wet etching using buffered hydrofluoric acid (see FIG.
c)). Next, after the resist is completely removed, the silicon substrate 1 is wet-etched by TMAH using the remaining thermal oxide film as a mask as shown in FIG. 6 (6-d). Subsequently, as shown in FIG. 6 (6-e), the entire surface of the oxide film 8 is peeled off with buffered hydrofluoric acid. The etched portions serve as diaphragms and channels of the micropump.

Next, as shown in FIG. 6 (6-f), an oxide film 8 having a thickness of 1.2 μm is formed on the entire surface again by thermal oxidation, and the valve diaphragm and the pumping diaphragm are brought to the same position as the surface by using a double-sided aligner. As described above, the resist is patterned on the back surface. Using this resist as a mask, the oxide film 8 is patterned with buffered hydrofluoric acid (FIG. 6 (6-g)), and after the resist is completely removed, silicon oxide is added with a potassium hydroxide solution as shown in FIG. 6 (6-h). The substrate 1 is etched. By adjusting the etching depth, the thickness of each diaphragm can be arbitrarily determined. Finally, FIG.
As shown in i), the oxide film 8 is entirely stripped with buffered hydrofluoric acid, and a substrate having a diaphragm is completed.

Next, as shown in FIG. 7, the glass substrate 2 is bonded to the silicon substrate 1. A through hole 5 having a diameter of 0.6 [mm] is formed in the glass substrate 2 in advance by an excimer laser. Corresponds to the position of the valve diaphragm formed on the silicon substrate (FIG. 7 (7-a)). Subsequently, anodic bonding is performed with the packing formed in advance in the shape of the valve diaphragm sandwiched between the glass substrate and the silicon substrate (FIGS. 7 (7-b) and 7 (7-c)). If heat-resistant silicone rubber or the like is used as the packing, it can sufficiently withstand anodic bonding at about 300 ° C. and about 1000 V.

By performing the joining with the packing sandwiched in this way, the through hole 5 is directly connected to the packing 4.
Thus, a structure closed by can be realized. At this time, the valve is sandwiched by a packing thicker than the etching depth of the valve diaphragm 6, whereby the valve can be normally closed due to the rigidity of the diaphragm and the packing (FIG. 5). Therefore, the strength of the valve with respect to the external pressure can be freely adjusted by arbitrarily setting the thickness of the packing or the valve diaphragm. Finally, the piezoelectric element 3 is attached to the valve diaphragm 6 and the pumping diaphragm 7 to form a unimorph actuator (FIG. 7 (7-d)). FIG. 7 (7-e) is a plan view of the completed micropump.

Next, how the valve is opened and closed will be described with reference to FIG. FIG. 11 (11-a) is a plan view of the micropump. FIG. 11 (11-b) and FIG. 11 (11-c)
FIG. 11 (11-d) and FIG. 11 (11-e) show cross sections BB ′ of FIG. 11 (11-a). The two valves are normally kept closed (Fig. 11 (11-
b), FIG. 11 (11-d)), by bending the unimorph actuator downward, a space is created between the glass substrate and the packing (FIG. 11 (11-c), FIG. 11 (11-e)). It is possible to pass through the through hole. In this case, the center portion of the diaphragm undergoes the largest displacement by the unimorph actuator, and the peripheral portion hardly displaces. Therefore, by setting the width of the packing and the width of the valve diaphragm to be the same, the packing does not move even when the valve is opened.

Further, by discharging the pumping diaphragm upward by a unimorph actuator, fluid can be discharged. By driving the two valve diaphragms and the one pumping diaphragm in order, the liquid supply of the micropump is realized. . Since an active valve is used, the suction side and the discharge side can be switched by changing the driving order of each actuator.

Since such a micropump uses a unimorph actuator using a piezoelectric element, a very thin one can be manufactured. Since an active valve is used, bidirectional liquid transfer is possible. . Further, since the packing is sandwiched between the glass substrate and the valve diaphragm, a micropump having high pressure resistance and high liquid sending efficiency can be realized.

[Embodiment 2] First, FIG.
By following the same steps as described above, the valve diaphragm 6 and the pumping diaphragm 7 are formed on the silicon substrate (FIG. 8 (8-a)). Subsequently, the through hole 5 is processed on the glass substrate by an excimer laser, and the through hole 5 has a structure located at a position away from the packing 4 (see FIG.
a)). Therefore, the fluid that has entered through the through hole 5 is blocked by the packing 4 sandwiched between the valve diaphragm and the glass substrate.

Subsequently, anodic bonding is performed in a state where a packing having the same width as the valve diaphragm is sandwiched between the glass substrate and the silicon substrate in advance (FIG. 8 (8-)).
c)). If heat-resistant silicone rubber or the like is used as the packing, it can sufficiently withstand anodic bonding at about 300 ° C. and about 1000 V. FIG. 8 (8-e) shows a plan view of the micropump. By using the packing having the same width as the diaphragm, a structure in which the fluid passing through the through hole is blocked by the packing is used. Is achieved. At this time, by sandwiching the gasket with a packing thicker than the etching depth of the valve diaphragm, the valve can be normally closed due to the rigidity of the diaphragm and the packing (FIG. 5). Therefore, the strength of the valve with respect to the external pressure can be freely adjusted by arbitrarily setting the thickness of the packing or the valve diaphragm. Finally, the piezoelectric element 3 is attached to the valve diaphragm 6 and the pumping diaphragm 7 to form a unimorph actuator (FIG. 8 (8-
d)).

Next, how the valve is opened and closed will be described with reference to FIG. FIG. 12 (12-a) is a plan view of the micropump. FIG. 12 (12-b) and FIG. 12 (12-c)
FIG. 12 (12-d) and FIG. 11 (12-e) show cross sections BB ′ of FIG. 12 (12-a). The two valves are normally kept closed (Fig. 12 (12-
b), FIG. 12 (12-d)), a space is created between the glass substrate and the packing and between the valve diaphragm and the packing by bending the unimorph actuator downward (FIG. 12 (1)).
2-c), FIG. 12 (12-e)) The fluid can pass through. In this case, the center portion of the diaphragm undergoes the largest displacement by the unimorph actuator, and the peripheral portion hardly displaces. Therefore, by setting the width of the packing and the width of the valve diaphragm to be the same, the packing does not move even when the valve is opened.

Further, by discharging the pumping diaphragm upward by a unimorph actuator, fluid can be discharged. By driving the two valve diaphragms and the one pumping diaphragm in order, a micro pump can be supplied. . Since an active valve is used, the suction side and the discharge side can be switched by changing the driving order of each actuator.

Since such a micropump uses a unimorph actuator using a piezoelectric element, a very thin one can be manufactured. Since an active valve is used, bidirectional liquid transfer is possible. . Further, since the packing is sandwiched between the glass substrate and the valve diaphragm, a micropump having high pressure resistance and high liquid sending efficiency can be realized.

[Embodiment 3] First, FIG.
By following the same steps as described above, the valve diaphragm 6 and the pumping diaphragm 7 are formed on the silicon substrate. Subsequently, as shown in FIG. 9 (9-a), the glass substrate 2 and the valve diaphragm 6 are coated with an adhesion preventing layer 9. At this time, by using an adhesion preventing layer such as a fluororesin, it is possible to prevent silicone rubber or the like from adhering during curing. In this state, the through hole 5 through which the fluid passes is processed on the glass substrate 2 by using an excimer laser.
(FIG. 9 (9-b)). The position of the through hole also matches the position of the valve diaphragm 6 of the silicon substrate. The glass substrate 2 thus processed and the silicon substrate 1 are bonded by anodic bonding as shown in FIG. 9 (9-c).

Subsequently, a low-viscosity silicone rubber before curing is filled into the diaphragm through the through-hole 5 and then cured, thereby realizing the packing 4 having high hermeticity (FIG. 9 (9-d)). Glass substrate 2 and valve diaphragm 6
Is coated with an adhesion preventing layer 9 in advance, so that the packing does not adhere to either side even after curing, and as a result, a structure in which the packing is sandwiched between the glass substrate and the valve diaphragm can be realized. Finally, the piezoelectric element 3 is attached to the valve diaphragm 6 and the pumping diaphragm 7 to form a unimorph actuator (FIG. 9 (9-e)). FIG. 9 (9-f) is a plan view of the completed micropump.

Next, how the valve is opened and closed will be described with reference to FIG. FIG. 11 (11-a) is a plan view of the micropump. FIG. 11 (11-b) and FIG. 11 (11-c)
FIG. 11 (11-d) and FIG. 11 (11-e) show cross sections BB ′ of FIG. 11 (11-a). The two valves are normally kept closed (Fig. 11 (11-
b), FIG. 11 (11-d)), by bending the unimorph actuator downward, a space is created between the glass substrate and the packing (FIG. 11 (11-c), FIG. 11 (11-e)). It is possible to pass through the through hole. In this case, the center portion of the diaphragm undergoes the largest displacement by the unimorph actuator, and the peripheral portion hardly displaces. Therefore, by setting the width of the packing and the width of the valve diaphragm to be the same, the packing does not move even when the valve is opened.

The fluid can be discharged by bending the pumping diaphragm upward by the unimorph actuator, and the micropump can be supplied by driving the two valve diaphragms and the one pumping diaphragm in order. . Since an active valve is used, the suction side and the discharge side can be switched by changing the driving order of each actuator.

Since such a micropump uses a unimorph actuator using a piezoelectric element, a very thin one can be manufactured. Since an active valve is used, bidirectional liquid transfer is possible. . Further, since the packing is formed by filling with silicone rubber, a micropump having high pressure resistance and high liquid sending efficiency can be realized.

[Embodiment 4] First, FIG.
By following the same steps as described above, a valve diaphragm and a pumping diaphragm are formed on a silicon substrate. Subsequently, as shown in FIG. 10 (10-a), the glass substrate 2 and the valve diaphragm 6 are coated with an adhesion preventing layer 9. At this time, by using an adhesion preventing layer such as a fluororesin, it is possible to prevent silicone rubber or the like from adhering during curing. In this state, the through holes 5 are formed on the glass substrate 2 using an excimer laser. There are two types of through-holes, one for allowing fluid to pass through, and one for filling packing in the diaphragm. Of these, the through-hole is processed in the same portion as the adhesion preventing layer 9 ( FIG. 10 (10-b). The glass substrate 2 and the silicon substrate 1 that have been subjected to such processing are shown in FIG.
Bond by anodic bonding as shown in (10-c).

Subsequently, a low-viscosity silicone rubber before curing is filled in the diaphragm through the through-hole 5 and cured to realize a highly sealed packing 4 (FIG. 10 (10-)).
d)). Since the glass substrate and the valve diaphragm are coated with the adhesion preventing layer 9 in advance, the packing does not adhere to either side, and as a result, a structure in which the packing is sandwiched between the glass substrate and the valve diaphragm can be realized. Further, the filling hole is closed with the sealant 10 so that the fluid that has passed through the valve does not leak outside (FIG. 10 (10-e)). This realizes a structure in which fluid flows in and out of the remaining two through holes, and the flow is blocked by the packing. Finally, the piezoelectric element 3 is attached to the valve diaphragm 6 and the pumping diaphragm 7 to form a unimorph actuator (FIG. 10 (10-f)). FIG. 10 (10-g) is a plan view of the completed micropump.

Next, how the valve is opened and closed will be described with reference to FIG. FIG. 12 (12-a) is a plan view of the micropump. FIG. 12 (12-b) and FIG. 12 (12-c)
FIG. 12 (12-d) and FIG. 11 (12-e) show cross sections BB ′ of FIG. 12 (12-a). The two valves are normally kept closed (Fig. 12 (12-
b), FIG. 12 (12-d)), a space is created between the glass substrate and the packing and between the valve diaphragm and the packing by bending the unimorph actuator downward (FIG. 12 (1)).
2-c), FIG. 12 (12-e)) The fluid can pass through the through-hole. In this case, the center portion of the diaphragm undergoes the largest displacement by the unimorph actuator, and the peripheral portion hardly displaces. Therefore, by setting the width of the packing and the width of the valve diaphragm to be the same, the packing does not move even when the valve is opened.

The fluid can be discharged by bending the pumping diaphragm upward by the unimorph actuator, and the micropump can be supplied by driving the two valve diaphragms and the one pumping diaphragm in order. . Since an active valve is used, the suction side and the discharge side can be switched by changing the driving order of each actuator.

Since such a micropump uses a unimorph actuator using a piezoelectric element, a very thin one can be manufactured. Since an active valve is used, bidirectional liquid transfer is possible. . Further, since the packing is formed by filling with silicone rubber, a micropump having high pressure resistance and high liquid sending efficiency can be realized.

[0033]

Since the micropump of the present invention uses a unimorph structure of a silicon diaphragm and a piezoelectric element, it can be manufactured very thinly, and has an effect that downsizing is easy. In addition, applying a structure in which the packing is sandwiched between a glass substrate and a silicon substrate,
By realizing a highly sealed micro valve,
This has the effect that high efficiency of pressure resistance and discharge performance can be achieved.

[Brief description of the drawings]

1A and 1B are a plan view and a cross-sectional view illustrating a structure of a micropump according to the present invention.

FIG. 2 is a cross-sectional view showing the structure of a conventional micropump.

FIG. 3 is a cross-sectional view illustrating a structure of a conventional micropump.

FIG. 4 is a cross-sectional view showing the structure of a conventional micropump.

FIG. 5 is a sectional view showing a valve structure of the micro pump of the present invention.

FIG. 6 is a cross-sectional view illustrating a method for manufacturing the micropump of the present invention.

7A and 7B are a cross-sectional view and a plan view showing a structure and a manufacturing method of the micropump of the present invention.

FIG. 8 is a cross-sectional view and a plan view showing a structure and a manufacturing method of the micropump of the present invention.

FIG. 9 is a cross-sectional view and a plan view showing a structure and a manufacturing method of the micropump of the present invention.

FIG. 10 is a sectional view and a plan view showing a structure and a manufacturing method of the micropump of the present invention.

FIG. 11 is a plan view and a sectional view showing a valve structure of the micropump of the present invention.

FIG. 12 is a plan view and a sectional view showing a valve structure of the micropump of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Silicon substrate 2 Glass substrate 3 Piezoelectric element 4 Packing 5 Through hole 6 Valve diaphragm 7 Pumping diaphragm 8 Oxide film 9 Adhesion prevention layer 10 Sealant 21 Liquid suction / discharge member 22 Stacked piezoelectric actuator 23 Valve 24 Flow passage port 25 Pump Chamber 26 casing 31 silicon substrate 32 polysilicon 33 glass substrate 34 piezoelectric element 41 pump chamber 42 piezoelectric element for pump 43 valve element 44 piezoelectric element for fluid control valve 45 flow control valve 46 controller

Claims (6)

[Claims] 1. A top plate portion having a through hole through which a fluid passes, a substrate portion having a pumping diaphragm for pushing out the fluid and a valve diaphragm for opening and closing a valve, and a unimorph actuator of a diaphragm and a piezoelectric element. A micropump comprising: a driving unit; and a packing that intercepts a fluid while being sandwiched between a top plate unit and a substrate unit. 2. The packing according to claim 1, wherein a packing is sandwiched between the top plate and the valve diaphragm, and the through hole of the top plate through which the fluid passes is directly closed by the packing. Micro pump. 3. A fluid having a structure in which a packing is sandwiched between a top plate and a valve diaphragm, wherein the packing is located at a position where the packing is separated from the through hole of the top plate through which the fluid passes, and the fluid passes through the through hole. The micropump according to claim 1, wherein the gas is blocked by packing. 4. A step of forming a through hole through which a fluid passes in the top plate, a step of forming a diaphragm in the substrate, a step of joining the top plate and the substrate with a packing sandwiched therebetween, and a step of forming a diaphragm. 2. The method for manufacturing a micropump according to claim 1, comprising a step of forming a driving unit of the piezoelectric element by a unimorph actuator. 5. A step of forming a through-hole in the top plate part for passing a fluid and filling a packing, a step of forming a diaphragm in the substrate part, and forming an adhesion preventing layer on the top plate part and the valve diaphragm. A step of joining the top plate portion and the substrate portion, filling the packing between the top plate portion and the valve diaphragm and curing the same, and forming a driving unit of the diaphragm and the piezoelectric element by a unimorph actuator. Item 7. A method for producing a micropump according to Item 1. 6. A step of forming a through hole through which a fluid passes through and a filling hole for filling a packing in the top plate portion, a step of forming a diaphragm in the substrate portion, and an adhesion preventing layer between the top plate portion and the valve diaphragm. Forming, bonding the top plate and the substrate, filling the packing between the top plate and the valve diaphragm and curing, and forming a driving unit of the diaphragm and the piezoelectric element by a unimorph actuator. And the step of closing the filling hole with a sealant.