JP2000167787A - Micro object transportation device, manufacture of micro object transportation device, and transportation method for micro object - Google Patents

Abstract

PROBLEM TO BE SOLVED: To transport micro parts of a micro machine efficiently and horizontally. SOLUTION: Many minute V-shaped grooves 2 are provided on an Si substrate 1 in such a manner that projection and recessed parts are provided repeatedly, a piezoelectric body film 4 is arranged on an inclined face 2a on one side on the same side of each V-shaped groove 2, and a cavity 5 is provided on a rear surface side of the inclined face 2a of the V-shaped groove in which the piezoelectric body film 4 is arranged so that the inclined face 2a of the V-shaped groove having the cavity 5 acts as a vibration plate. The vibration in the direction orthogonal to the inclined face 2a is given to a micro object on the groove 2 by the piezoelectric body film 4 and the vibration plate to move the micro object to the next groove 2 sequentially.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for transporting a small object suitable for continuously transporting a small object as handled by a micromanipulator, a method for manufacturing the device for transporting a small object, and a method for transporting a small object. Things.

[0002]

2. Description of the Related Art With the recent development of electronic technology and mechatronics, micromachines have become micromanipulators,
It is used in a wide range of industrial fields such as defect inspection of print patterns and liquid ejectors requiring minute high-speed driving. Such a micromachine performs a rotary drive, a linear drive, a pressing drive, and the like according to its use, and is configured by combining mechanical parts such as gears having a size of a micron unit, a minute motor, a small actuator, a sensor, and the like.

[0003] Regarding the handling of minute parts of these micromachines, for example, see the paper "Journal of the Robotics Society of Japan V
ol. 14 NO. 8, PP ・ 1113 ~ 1116,1
As described in “996”, it is common to assemble by moving, transporting, transporting, etc., one by one a small part by grasping it in a tweezers manner using a micromanipulator.

[0004]

However, since the micromanipulator adopts a configuration in which the microparts are gripped and moved one by one in a tweezers type, it takes time and effort to handle the microparts. Further, it is not suitable for continuous transportation of a large amount of minute objects.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the above-mentioned problems, and to transport a minute object or the like of a micromachine efficiently in a horizontal direction, a method of manufacturing the minute object transport apparatus, and a minute object. Transport method.

[0006]

Means for Solving the Problems The present invention has been proposed in order to achieve the above-mentioned object, and the present invention is directed to a semiconductor device having a continuous V-shaped groove formed on a substrate so as to repeat the irregularities. And a piezoelectric film having an electrode is disposed on one of the slopes located on the same side of each V-shaped groove, and the piezoelectric film causes a minute object on the groove to vibrate in a direction perpendicular to the slope. A minute object transport device characterized in that the minute object is provided so that the minute object can be sequentially moved to an adjacent groove.

According to a second aspect of the present invention, a cavity is formed on the back side of the slope of the V-shaped groove provided with the piezoelectric film,
A minute object transporting device characterized in that a slope of a V-shaped groove provided with the piezoelectric film functions as a diaphragm.

According to a third aspect of the present invention, fine V-shaped grooves are continuously provided on a Si substrate so that irregularities are repeated, and an SiO ₂ film is formed on the surface of the V-shaped grooves. A cavity is formed by disposing a piezoelectric film on one slope located on the same side, and removing the Si substrate on the back side of the slope of the V-shaped groove on which the piezoelectric film is arranged. The remaining SiO ₂ film is used as a vibration plate, and the vibration plate is vibrated by the piezoelectric film to apply a vibration in a direction perpendicular to the slope to the minute object on the groove so that the minute object can be sequentially moved to the next groove. A minute object transport device characterized by having such a configuration.

According to a fourth aspect of the present invention, there is provided a double-sided silicon substrate oxide film forming step of forming a SiO ₂ film on both sides of a silicon wafer, and a step of forming the SiO ₂ film on the device side on the opposite side by a first patterning mask. SiO ₂ film is simultaneously patterned on both sides of the SiO ₂ film using a second patterning mask
And ₂ patterning step, a V-groove forming step of forming a V-shaped groove is anisotropically etched only devices face, and the SiO ₂ removal step of removing the SiO ₂ film of the devices surfaces, S
a silicon substrate double-sided oxide film forming step of forming an SiO ₂ film on both sides of the i-substrate, a back side SiO ₂ unnecessary portion removing step of half-etching the back side SiO ₂ film of the Si substrate, and a conductive material serving as a lower electrode on the device surface Forming a lower electrode, forming a PZT film as a piezoelectric film on the lower electrode, and forming a conductive film as an upper electrode on the PZT. An electrode film forming step, a device surface patterning step of etching at least an upper electrode conductive film and a piezoelectric film to form an upper electrode, a piezoelectric film, and a lower electrode; and forming a piezoelectric film on a slope of a V-shaped groove. And a cavity forming step of forming a cavity by removing the Si under the SiO ₂ film constituting the inclined surface by etching from the back surface, thereby forming a cavity. is there.

According to a fifth aspect of the present invention, the V-shaped groove is provided continuously so that the unevenness is repeated, and the piezoelectric material is provided on one of the pair of opposed slopes of each V-shaped groove located on the same side. A micro object is placed on a substrate on which a film is provided, and the micro object is sequentially moved to an adjacent groove by applying vibration in a direction perpendicular to the slope to the micro object on the groove with the piezoelectric film. This is a method for transporting minute objects.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on the illustrated embodiment.

In FIG. 1, reference numeral 1 denotes a semiconductor substrate Si
Substrate 2 and fine V-shaped grooves 2 are provided on the Si substrate 1 so as to be continuously arranged so that irregularities are repeated. The V-shaped groove 2 is made of an SiO ₂ film 3 which is an oxide film formed on the surface of the Si substrate 1.

A pair of opposed slopes 2a, 2 of each V-shaped groove 2
A piezoelectric film 4 composed of a piezo element (PZT) is provided on one slope 2a located on the same side of b.
As shown in FIG. 5, the piezoelectric film 4 has an upper electrode 4a on the upper surface and a lower electrode 4b on the lower surface, and the lower electrode 4b is joined to the slope 2a of the V-shaped groove 2. Then, a cavity 5 is provided on the back surface side of the slope 2a of the V-shaped groove 2 in which the piezoelectric film 4 is provided. As a result, the V-shaped groove 2
Of the slopes, the slope 2a on which the piezoelectric film 4 is disposed is thin S
It is composed of only the iO ₂ film 3 and is configured to function as a diaphragm of the piezoelectric film 4.

The device for transporting minute objects configured as described above can be manufactured roughly as follows.

First, as shown in FIG. 3, a V-shaped groove 2 is formed on a Si substrate 1 made of a silicon wafer having a (110) plane orientation at a tilt of 54 ° from the orientation flat OF. As shown in FIG. 4, a patterning mask 8 having a predetermined gap is arranged on a Si substrate 1 and anisotropic wet etching is performed so that the slope is 35 ° with respect to the (110) plane. It is formed as a V-shaped groove having an inclined V angle θ. At this time, the region immediately below the patterning mask 8 is also over-etched, which contributes to the formation of a V-shaped groove.

It is to be noted that a Si substrate 1 having a (100) main surface can also be used, and in this case, the V angle θ formed by the slope with respect to the main surface is 45 °. 1 and 2 correspond to the A-A 'cross section of the V-shaped groove 2 of FIG. 3 obtained in this manner.

FIG. 7 shows upper and lower electrodes 4a, 4a of the piezoelectric film 4.
8 shows a waveform of an applied voltage applied to the piezoelectric film 4b.
FIG.

As shown in FIG. 8, in the standby state (1) where no voltage is applied, the piezoelectric film 4 does not bend (FIG. 8A).
), The piezoelectric film 4 bends in the charged state (2) in the process of raising the voltage waveform, and the SiO ₂ film 3 as the diaphragm is bent accordingly, and the bent state is maintained for a constant voltage (holding). State (3), FIG. 8 (b)). Then, in the discharge state (4) where the applied voltage is returned to zero, the piezoelectric film 4 and the SiO ₂ film 3 return to the original state, no bending occurs, and return to the standby state (5) (FIG. 8 (c)).

As described above, the electrodes 4a,
4b, a voltage (FIG. 7) is applied to generate a vibration (FIG. 8) in the direction perpendicular to the slope 2a on the piezoelectric film 4, thereby exciting the vibration plate made of the SiO ₂ film 3. Basically, all the piezoelectric films 4 are simultaneously driven in the same phase. In this state, when a micro component 6 of a micro machine is placed on the V-shaped groove 2 as a relatively large micro object, for example, as shown in FIG. 2, the micro component 6 can be sequentially moved to an adjacent groove. In FIG. 2, reference numeral 7 indicates a movement locus (flow line) of the center point of the micro component 6.

With respect to the minute object handled in the present invention, the adhesive force such as van der Waals force and electrostatic force cannot be ignored against gravity. Therefore, when moving the object, a force against the adhesive force is required.

FIG. 5 shows the principle of transporting the minute parts 6 in the minute object transporting apparatus.

When the piezoelectric film 4 provided on one slope 2a of the V-shaped groove 2 vibrates, the relatively large micro-parts 6 move to the adjacent groove due to the vibration against the adhesive force.
It is possible to transport the micropart 6 by sequentially repeating the movement to the adjacent groove.

On the other hand, as shown in FIG. 6A, when a powder (granular substance or powdery substance) 9 which is a relatively small minute object is handled, a force as shown in FIG. Acts on small objects. Then, the propulsive force, which is the resultant force of the adhesive force, gravity, and PZT vibration, is the force for moving the minute object to the lower side of the slope 2a. Further, as shown in FIG. 6C, the minute objects 9 collected in the lower part of the V-shaped groove 2 are caused by the propulsive force to generate the slope 2b.
Is pushed upward. Then, as shown in FIG. 6D, the minute object at the uppermost end of the slope 2b is pushed up by the minute object ascending on the slope 2b, climbs over the top of the V-shaped groove 2 and the adjacent V-shaped groove. Move to 2.

According to such a principle, powder which is a relatively small minute object can be transported.

As described above, the applied voltage 10 is basically applied simultaneously to all the piezoelectric films 4 in the same phase and driven. The frequency of the applied voltage 10 is set to a low frequency drive of about 1 Hz to 1 kHz for a relatively large object such as a minute component, and 1 kHz for a relatively small object such as a powder.
High-frequency driving of about z to 10 kHz is performed.

However, in the case of a relatively large object such as a small component, the piezoelectric film 4 may be driven with the phase shifted.

By providing the piezoelectric film 4 to be driven and the piezoelectric film 4 not to be driven, the object can be stopped at an arbitrary position.

As described above, according to the apparatus for transporting minute objects, it is possible to easily and continuously move, transport, and transport one to a large number of minute objects, and it is possible to transport the above objects horizontally. is there. In addition, the micro object transport device can be used not only for assembling a micro machine, but also for a micro factory for preparing a chemical powder.

Next, a specific manufacturing method will be described.

(A) Step of Forming Double-Sided Oxide Film on Si Substrate First, on both sides of a 100-1000 μm-thick Si substrate 1 made of a silicon wafer having a (110) main plane orientation at 1000-1200 ° C. By baking in a diffusion furnace for up to 3 hours, an SiO ₂ film 11 as an oxide film is formed to a thickness of 0.5 to 3 μm (FIG. 9A). In this embodiment, the thickness of the Si substrate 1 is 220 μm.
m, the thickness of the SiO ₂ film 11 is 1 μm.

(B) SiO ₂ patterning step Next, the SiO ₂ film 11 on the device side (PZT formation side)
Is formed by the first patterning mask 8a having a predetermined width W1 and a predetermined pitch P1, and the SiO ₂ film 11 on the device side is
Are simultaneously patterned on both sides by a second patterning mask 8b having a predetermined width W2 and a predetermined pitch P2 (FIG. 9).
(B)). This is based on ordinary photolithographic etching using HF (hydrofluoric acid) as an etchant. The predetermined width W1 of the patterning mask 8a is 3 to 10 μm (5 μm in this embodiment), and the predetermined pitch P1 is 10 to 500 μm.
m (25 μm in this embodiment). The patterning mask 8b has a length of 6.5 to 255 μm (15 μm in the present embodiment) starting from the center of the predetermined pitch P1 of the patterning mask 8a and ending at the center of the adjacent predetermined width W1.
m).

(C) V-groove forming step Only on the device surface side, a KOH aqueous solution (for example, 10%),
Alternatively, Si is anisotropically etched with a TMAH aqueous solution (FIG. 9C). Since silicon is etched first in the depth direction due to anisotropy, etching proceeds in a V-shape due to side etching. By performing this anisotropic wet etching, it is possible to form a V-shaped groove having a V angle θ in which the slope is inclined at 35 ° with respect to the (110) plane.

(D) SiO ₂ removing step The SiO ₂ film is removed only on the device surface (FIG. 9).
(D)).

(E) Si substrate double-sided oxide film forming step On both surfaces of the Si substrate 1, an SiO ₂ film 3 as an oxide film
It is formed to a thickness of 5 to 3 μm (1 μm in the present embodiment) (FIG. 10E).

(F) Backside SiO ₂ Unnecessary Part Removal Step Only the SiO ₂ film 11 on the back side of the Si substrate 1 is half-etched (FIG. 10F).

(G) Lower Electrode Forming Step A lower electrode (Pt, Ir, RuO ₂ etc.) conductive film 12 is formed on the device surface by a sputtering method to a thickness of 200 to 800 nm (500 nm in the present embodiment). (FIG. 10
(G)).

(H) PZT film forming step and upper electrode forming step The PZT piezoelectric film 13 is formed in a thickness of 0.5 to 10 by a sol-gel method, a sputtering method, a CVD method, a laser ablation method or the like.
After forming a film having a thickness of 1 μm (in this embodiment, 1 μm),
Annealed and crystallized by an RTA apparatus at ~ 900 ° C, and then an upper electrode conductive film 14 was formed by sputtering method from 50 to 2 ° C.
A film is formed with a thickness of 00 nm (100 nm in this embodiment) (FIG. 10H).

(I) Device surface patterning step The upper electrode conductive film 14, the piezoelectric film 13, and the lower electrode conductive film 12 are etched by an ion milling device, an RIE device, or the like, and the upper electrode 4a, the piezoelectric film 4, Lower electrode 4b
Is formed (FIG. 11 (i)). At that time, the lower electrode conductive film 12 may be left.

(J) Backside Si Etching Step The backside is etched with a KOH aqueous solution (for example, 10%) or a TMAH aqueous solution (FIG. 11 (j)).
As a result, the portion of the slope 2a, 2b of the V-shaped groove 2 that is not covered with the SiO ₂ film, ie, the S below the SiO ₂ film 3 that forms the slope 2a on which the piezoelectric film 4 is formed, is formed.
i is removed, thereby forming the cavity 5.

(K) Completion When the device completed as described above is viewed from the back surface, as shown in FIG. 11 (k), the etched cavity 5 exists as a recess in a part of the semiconductor substrate. I do. Therefore, the device has a solid structure. Note that (i) and (j) in FIG. 11 correspond to A in FIG. 11 (k).
-A 'section.

FIG. 12 (l) is a plan view of the device surface as viewed from above. As shown in this figure, the lower electrode 4b
Are the common electrodes of the PZT elements in each V-shaped groove 2.

Further, FIG. 12 (m) shows B in FIG. 12 (l).
It is -B 'sectional drawing. As shown in this figure, PZT is S
The upper electrode 4a extends to the outside of the i-etched portion, and serves as an individual PZT electrode of each V-shaped groove 2 thereon.

[0043]

As described above, according to the present invention, fine V-shaped grooves are continuously provided on a semiconductor substrate so that irregularities are repeated, and the same V-shaped groove is formed on the same side of a pair of opposed slopes. A piezoelectric film is disposed on one of the slopes located, and the piezoelectric film imparts a vibration in a direction perpendicular to the slope to the minute object on the groove so that the minute object can be sequentially moved to an adjacent groove. Therefore, minute objects such as inorganic powders, organic powders, and minute parts having a size of 500 μm to 1 nm can be easily moved, transported, and conveyed in large quantities.

Further, a cavity is provided on the back side of the slope of the V-shaped groove in which the piezoelectric film is provided, and the slope of the V-shaped groove in which the piezoelectric film is provided functions as a diaphragm. By acting as a diaphragm on the slope of the V-shaped groove, a minute object can be efficiently moved, transported, and conveyed.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a minute object transport device.

FIG. 2 is a front view of the small object transporting apparatus showing a state in which a relatively large small object is handled.

FIG. 3 is an explanatory diagram showing a state in which a V-shaped groove of the minute object transport device is formed on a silicon wafer.

FIG. 4 is an explanatory view showing a step of forming a V-shaped groove of the minute object transporting apparatus by etching.

FIG. 5 is an explanatory diagram illustrating a principle of transporting a relatively large minute object.

FIG. 6A is a front view of a relatively wide range of a small object transporting device showing a state in which a relatively small minute object is handled, and FIG. 6B is a view showing a small object on PZT in one V-shaped groove. Explanatory diagram of the acting force, (c) is an explanatory diagram of the force acting on the minute object located at the top of the slope, and (d) shows the state in which the minute object shown in (c) has moved to the adjacent V-shaped groove. FIG.

FIG. 7 is an explanatory diagram showing a voltage waveform applied to a piezoelectric film of the minute object transport device.

8A and 8B are explanatory diagrams showing a change in deflection of the piezoelectric film when the voltage waveform of FIG. 7 is applied, where FIG. 8A shows a standby state, FIG. (C) shows the original standby state after discharging.

9A and 9B are explanatory views showing a part of the manufacturing process of the minute object transport device, wherein FIG. 9A shows the formation of a double-sided oxide film on a Si substrate, FIG. 9B shows the patterning of SiO ₂ , FIG. ) Is S
is an explanatory diagram showing an iO ₂ removal step.

FIGS. 10A and 10B are explanatory views showing a part of the manufacturing process of the minute object transporting apparatus, wherein FIG.
Is the removal of the unnecessary portion of the back surface SiO ₂ , (g) is the lower electrode film formation,
(H) is an explanatory view showing the configuration of PZT film formation and upper electrode film formation.

FIGS. 11A and 11B are explanatory views showing a part of a manufacturing process of the minute object transporting apparatus, wherein FIG.
Is an explanatory view showing a step of etching Si on the back surface, (k).
FIG. 4 is an explanatory view showing a completed state.

FIG. 12 is a continuation of the explanatory view of FIG. 11, wherein (l) is a plan view of the device surface as viewed from above, and (m) is BB ′ of (l).
It is sectional drawing.

[Explanation of symbols]

1 Si substrate 2 V-groove 2a, 2b slope 3 SiO ₂ film 4 piezoelectric film 4a, 4b electrode 5 cavity 6 microcomponents (minute objects) 7 movement locus 8, 8a, 8b patterned mask 9 powder 10 applied voltage 11 SiO ₂ film 12 lower electrode conductive film 13 piezoelectric film 14 upper electrode conductive film

Claims (5)

[Claims] 1. A piezoelectric body having fine V-shaped grooves continuously formed on a substrate so that irregularities are repeated, and having an electrode on one of the pair of opposed slopes of each V-shaped groove located on the same side. A micro-object transportation characterized in that a film is provided, and the micro-object on the groove is subjected to vibration in a direction perpendicular to the slope by the piezoelectric film so that the micro-object can be sequentially moved to an adjacent groove. apparatus. 2. A cavity is formed on the back side of the slope of the V-shaped groove provided with the piezoelectric film, and the slope of the V-shaped groove provided with the piezoelectric film functions as a diaphragm. The apparatus for transporting minute objects according to claim 1, wherein: 3. A V-shaped groove is continuously provided on a Si substrate so that irregularities are repeated.
An O ₂ film is formed, a piezoelectric film is provided on one slope located on the same side of each V-shaped groove, and the Si substrate is removed on the back side of the slope of the V-shaped groove on which the piezoelectric film is provided. To form a cavity, and the Si remaining by the formation of the cavity is formed.
The O ₂ film is used as a vibration plate, and the vibration plate is vibrated by the piezoelectric film to apply vibration in a direction perpendicular to the slope to the minute object on the groove so that the minute object can be sequentially moved to the next groove. A small object transport device characterized by the above-mentioned. On both sides of 4. A silicon wafer, a Si substrate duplex oxide film forming step of forming a SiO ₂ film, the first patterned mask an SiO ₂ film of the devices face side, a second patterned SiO ₂ film on the opposite side A SiO ₂ patterning step of simultaneously patterning both surfaces with a mask, a V-groove forming step of forming a V-shaped groove by anisotropically etching only the device surface side, and a SiO ₂ removing step of removing the SiO ₂ film on the device surface. becomes a Si substrate duplex oxide film forming step of forming a SiO ₂ film on both surfaces of the Si substrate, and the backside SiO ₂ unnecessary portion removing step of half-etching the rear surface side of the SiO ₂ film of the Si substrate, a lower electrode devices face A lower electrode film forming step of forming a conductive film, a PZT film forming step of forming PZT to be a piezoelectric film on the lower electrode, An upper electrode film forming step of forming a conductive film to be an upper electrode on the ZT; and a device surface patterning for etching at least the upper electrode conductive film and the piezoelectric film to form an upper electrode, a piezoelectric film, and a lower electrode. A step of removing Si below the SiO ₂ film constituting the slope on which the piezoelectric film is formed among the slopes of the V-shaped groove by etching from the back surface, thereby forming a cavity. And a method for manufacturing a micro-transport device. 5. A substrate on which a V-shaped groove is provided continuously so that irregularities are repeated, and a piezoelectric film is disposed on one of a pair of opposed slopes of each V-shaped groove located on the same side. A micro object is placed on the micro object, and the micro object on the groove is vibrated in a direction perpendicular to the slope by the piezoelectric film to sequentially move the micro object to an adjacent groove.