JPH06297252A - Fine work method and device therefor - Google Patents

Abstract

PURPOSE:To enable fine work up to (mum) order from an electron level without requiring a large-scale device such as a vacuum device under a chemically stable condition against oxidation and the like by carrying out the fine work while impressing work voltage between a probe of a scanning tunneling microscope and a work object in liquid. CONSTITUTION:When fine work is carried out, an interval between the tip (lower end) of a probe 10 and a work object surface 11a of a work object 11 is maintained in a prescribed value by position control in the X, Y and Z directions. In this condition, working high voltage is impressed between the probe 10 and the work object 11 from working electric power supply. In this case, for example, when liquid 9 is electrolytic solution, the probe 10 is used as an anode, and the work object 11 is used as a cathode, and when bias voltage is impressed, a cation atom generated by ionization of the electrolyte solution is deposited in a fine pattern (as a fine projecting part) as a metallic atom onto a surface of the work object 11 situated just under the probe 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fine processing method and apparatus therefor, and more particularly to a method and apparatus suitable for fine processing required in the field of electronics.

[0002]

2. Description of the Related Art In the field of electronics, for example, with higher integration and miniaturization of elements, further development of microfabrication technology is required for drawing a mask for lithography and wiring processing inside the element.

As such a fine processing technique, exposure by a focused ion beam, processing such as drilling, exposure using ion beam excitation or laser beam excitation CVD, processing such as pattern deposition, etc. have been proposed. In the prior art, fine processing of about 0.2 μm (200 nm) is the limit.

In the field of magnetic recording, for example,
Due to the demand for narrower tracks of magnetic heads and shorter wavelength recording, further miniaturization of the element itself, that is, formation of a magnetic material film on a minute region of the core and fine processing technology are required.

Recently, a scanning tunneling microscope (hereinafter referred to as STM
Sometimes called. ) Is used in a vacuum or in a gas atmosphere, and fine processing is performed on semiconductor materials and metal materials. However, such a method requires a large-scale device such as a high-vacuum device, and also requires an atmosphere control to prevent oxidation and the like.

[0006]

SUMMARY OF THE INVENTION The object of the present invention is to eliminate the need for a large-scale device such as a high vacuum device and the like, especially under the condition that it is chemically relatively stable against oxidation and the like, especially on the work piece. It is an object of the present invention to provide a microfabrication method and a microfabrication apparatus capable of performing microfabrication in the range from the level to the μm order.

Another object of the present invention is to provide a method and apparatus for processing a two-dimensional or three-dimensional fine structure.

[0008]

That is, the present invention uses a scanning tunneling microscope (STM), and in a liquid, between the STM probe and the workpiece (for example, the probe and the workpiece surface). Between the probe and the work piece, with and being immersed in liquid)
The present invention relates to a method of applying a processing voltage to perform fine processing on the workpiece.

In the method of the present invention, two-dimensional processing is performed by repeating the above-described fine processing step in liquid by STM, or by repeating this fine processing step and a normal processing step by film formation or etching. Target or 3
It is desirable to form a dimensional fine structure.

In the method of the present invention, an electrolyte solution is used as the liquid, and predetermined atoms can be deposited in a fine pattern from the electrolyte. It is also possible to electrochemically corrode the work piece into a fine pattern.

The processing voltage (Et) is Et>
| 3V |, and the distance between the probe and the workpiece is 4 μm
It is desirable to process as less than.

Further, it is preferable to perform fine processing with the feedback circuit of the probe position control mechanism for controlling the distance between the workpiece and the probe opened. In this case, the position control of the probe with respect to the workpiece can be performed in the three-dimensional direction by the piezoelectric conversion element.

In carrying out the method of the present invention, a fine processing having a scanning tunneling microscope having a probe and a liquid container, and having a processing power source for applying a processing voltage between the probe and a workpiece. It is desirable to use the device.

[0014]

EXAMPLES Examples of the present invention will be described below.

First, referring to FIG. 3, a system of a fine processing apparatus using a scanning tunneling microscope (STM) according to this embodiment will be described.

The sample 12 is placed horizontally on the sample stage 21. Then, on the surface of the electrode 11 of the sample 12, the piezo element 23
The probe 10 fixed to is positioned vertically.

The sample stage 21 is movable in horizontal X and Y directions which are orthogonal to each other. To position the sample 12 in the X and Y directions, the laser length measuring machine 22 is used.
The measurement results of X and 22Y are input to the microcomputer 29, and the microcomputer 29 controls and drives a driving means (not shown).

Precise positioning of the probe 10 with respect to the sample 12 is performed by the substantially cylindrical piezo element 23 as follows.

The X-direction inner peripheral edge and outer peripheral edge of the piezo element 23 are connected to the X-direction scanning circuit 25, and the Y-direction inner peripheral edge and outer peripheral edge are connected to the Y-direction scanning circuit 26. The upper and lower ends (in the vertical direction) are connected to the Z-direction drive / servo circuit 27. Two pairs of connecting ends of the piezo element 23 to each circuit in the X direction, Y direction, and Z direction are provided at symmetrical positions, but only one set is shown in FIG. 3 and the other one set is not shown. I am doing it.

The X-direction scanning circuit 25, the Y-direction scanning circuit 26 and the Z-direction driving / servo circuit 27 are connected to a microcomputer 29. The microcomputer 29 uses an X-direction scanning circuit 25 and a Y-direction scanning circuit 2 via a feedback circuit 28.
6. Connected to Z direction drive / servo circuit 27. Probe 10
A tunnel current power supply 24 is connected to the thin film 11 and the tunnel current power supply 24 is connected to a microcomputer 29.

A cathode ray tube (CRT) 30A and a printer 30B are connected to the microcomputer 29, and the STM
It is possible to observe the surface condition of the electrode 11 by means of and record it. The surface state can be observed by STM with a resolution of atomic order of nm.

First, while monitoring the CRT 30A, the piezo element 23 is actuated by the microcomputer 29.
From the X-direction scanning circuit 25 and the Y-direction scanning circuit 26 to the piezo element
A voltage is applied to the piezoelectric element 23 to control the dimensions of the piezo element 23 in the X direction and the Y direction, so that the probe 10 is accurately positioned right above the desired position of the thin film 11.

In the present embodiment, in the above-described STM device, as shown in an enlarged view of FIG. 1, both the probe 10 and the thin film electrode 11 as a workpiece are provided on the sample stage 12 and the liquid 9 is discharged. The container 21 (for example, a container made of a rubber O-ring) that has been housed is immersed in the liquid 9. Therefore,
This STM device is called an STM in liquid, as opposed to one used in vacuum.

That is, in the liquid 9, the position control in the X and Y directions is performed as described above, and the probe 10 is moved in the X and Y directions.
The position in the direction is stopped at a predetermined point in the liquid 9, and then the dimension of the piezoelectric element 23 in the Z direction is changed by applying a voltage by the Z direction driving / servo circuit 27, and the tip of the probe 10 is connected to the electrode 11.
By approaching a distance of 0.1 to several 100 nm, a tunnel current flows and the surface condition of the electrode 11 can be observed as described above.

Next, for example, the feedback circuit portion connected to the Z direction driving / servo circuit 27 in the feedback circuit 28 is opened (OFF) to fix the position of the tip of the probe 10.

Next, at the time of fine processing, the distance d between the tip (lower end) of the probe 10 and the work surface 11a of the work piece 11 is controlled by the position control in the X, Y and Z directions. A machining power supply 44 is placed between the probe 10 and the workpiece 11 while maintaining a predetermined value.
Applies a high voltage (bias voltage) for processing.

In this case, for example, when the liquid 9 is an electrolyte solution, the probe 10 is used as an anode, the workpiece 11 is used as a cathode, and a bias voltage 44 is applied to the workpiece to be processed immediately below the probe 10. On the surface of the object 11, cation atoms generated by ionization of the electrolyte solution are deposited as metal atoms in a fine pattern (as fine protrusions). This can be referred to as electrolytic deposition.

Further, by applying a bias voltage using the side of the probe 10 as a cathode and the side of the workpiece 11 as an anode,
On the surface of the work piece 11 located immediately below 10, the electrochemical reaction of the constituent metals of the work piece 11 is locally caused to etch the work piece 11 in a so-called fine pattern. As a result, fine recesses can be formed on the surface of the workpiece 11 located directly below the probe 10.

Fine processing (deposition or etching) described above
Is considered to be a phenomenon basically similar to electrolytic plating or electrolytic corrosion reaction (electrolytic polishing). Therefore, the liquid 9 to be adopted can be appropriately selected in consideration of the material of the workpiece and the target processing state (whether to form the convex portion or the concave portion).

As the liquid 9 into which the probe 8 and the workpiece 11 are immersed, an electrolytic solution which is chemically relatively stable against oxidation and which is suitable for the intended processing can be used, but the electrolyte is not always required. The liquid is not limited to a solution, and a liquid exhibiting ion conductivity or a liquid not exhibiting ion conductivity can be used.

The container 21 for containing the liquid 9 may be a rubber O-ring provided so as to surround a predetermined surface of the workpiece 11 in the above description, but it should be composed of another container. You can also

In the present embodiment, in order to perform fine processing, it is desirable to make the distance d between the tip of the probe and the workpiece as small as possible. This distance d is d <4
Good results can be obtained when μm is set,
It is desirable to set it to several 100 nm to several nm.

Further, the ion current additionally flowing as the leak current is made as small as possible with respect to the tunnel current,
It is effective to eliminate the influence of the leak current on the tunnel current during surface observation. For this purpose, it is desirable to cover the part of the probe other than the tip part with an insulating wax or the like.

At the time of fine processing after the surface observation by the above-mentioned tunnel current, the Z-direction feedback circuit 28 is turned off.
Then, the distance between the tip of the probe and the surface of the workpiece does not change while the processing voltage is applied.

On the other hand, the feedback circuit 28 is OF
If it is not F, the distance between the work piece and the probe may change, and it may not be possible to apply the desired electric field strength to the work piece or the tip of the probe. The area to be processed becomes large, and it may not be possible to perform fine processing on the atomic level to the μm order.

Therefore, as described above, the probe 10 and the workpiece are processed.
The distance from the surface of 11 is always kept constant, and by confirming that it is kept constant like this by electrically turning off feedback in the Z direction, a large electric field is probed for a desired time. It can be surely applied only to the tip or only to a very limited region of the surface of the work piece located at the tip of the probe. For this reason, it is desirable to turn off the feedback circuit during processing. However, under a certain condition, the tunnel current may flow with the feedback in the Z direction turned off, but it is not necessary to flow it.

Immediately after the fine processing by applying the processing voltage, the Z-direction feedback of the piezo element 23 is recovered and the probe can be controlled again by the tunnel current. Next, the piezo elements in the X and Y directions are controlled and moved to another place where fine processing is desired, and voltage is applied in the same manner as described above. All of these are computer controllable and thus can be manipulated at any interval or in any shape. For example, when it is desired to perform linear processing, the voltage may be continuously applied.

Next, the procedure of fine processing according to the method of the present invention will be described by taking the case of forming fine convex portions (fine dots) as an example.

The position of the probe in the X and Y directions is stopped at a predetermined point, and then the distance between the tip of the probe and the surface of the workpiece is set to a predetermined value via the Z direction control circuit. Fix the probe tip position by opening the feedback circuit to the direction drive / servo circuit.

Next, a predetermined voltage is applied from the machining power source 44 with the probe side as the anode and the work piece side as the cathode to electrolyze the electrolyte solution, and as shown in FIG. The cation atoms forming the solution are deposited as fine dots 32.

For the observation of the surface to be processed, a predetermined tunnel current flows between the probe and the object to be processed, the feedback circuit is restored, and the probe is scanned (that is, it functions as a scanning tunneling microscope). It can be done by

Unlike the above method, fine recesses (holes)
Is formed by reversing the polarities of the machining voltages applied to the probe and the workpiece, that is, using the probe side as the cathode and the workpiece side as the anode. As a result, as shown in FIG. 2B, the workpiece 11 is locally removed to form the fine recess 33.

The distance d between the tip of the probe and the surface of the workpiece is d.
As described above, it is desirable to set d <4 μm in order to realize fine processing.

Then, this distance d is set as an interval in a state where a predetermined tunnel current is generated between the probe and the surface of the workpiece, and the feedback circuit to the Z-direction drive / servo circuit is opened to perform fine processing for a predetermined time. After that, the feedback circuit is restored (ON) to restore the state in which the predetermined tunnel current flows, and the distance d between the probe and the surface of the workpiece is restored to the above value repeatedly. be able to. As a result, it is possible to form a plurality of fine protrusions or recesses on the surface of the workpiece, or to form fine protrusions with a higher height or recesses with a finer depth. it can.

By the method described above, it is possible to form fine projections or depressions on the surface of the workpiece in any pattern such as dots or lines. Such fine processing is
Since it is based on the STM probe in a liquid, it is possible to perform fine processing under the condition that it is chemically stable against oxidation and the like without requiring a large-scale device such as a vacuum device.

Next, specific examples 1 to 4 of fine processing based on the above-described method of the present invention will be described together with comparative examples.

COMPARATIVE EXAMPLE 1 Using a gold (Au) thin film formed by sputtering on a silicon substrate as a cathode and a Pt-Ir wire as an anode, nickel was deposited on the gold thin film by a conventional electrolytic plating method. It was

As an electrolytic solution, a nickel sulfate solution (5 mM
A mixed solution of NiSO ₄ and 0.1 M H ₂ SO ₄ ) was used. The electrochemical reaction was carried out in a beaker with sufficient space between the electrodes (several cm or more). Bias voltage E of the Pt-Ir wire electrode with respect to the silicon substrate (gold substrate) on which the gold thin film is formed.
When t was Et> +3 V, the reaction current was remarkably increased, and it was confirmed that nickel was uniformly deposited on the entire surface of the gold substrate.
This is formed by the electrochemical reaction of Ni ²⁺ + 2e ⁻ → Ni on the gold electrode.

Similar electrochemical reactions were obtained in the three-electrode method in which a reference electrode serving as a reference for the potential of each electrode was provided. The three-electrode method is often used in the usual electrolytic plating method in order to accurately set the potential for the solution.

Example 1 In a commercially available scanning tunneling microscope (STM),
Using a gold thin film formed by sputtering on a silicon substrate as a substrate, a Pt-Ir probe was used, and a bias voltage of +200 mV (probe side was positive) and a tunnel current of 10 nA were used, and a 10 μm square The surface of the substrate was scanned in the same nickel sulfate solution as in Comparative Example 1.

However, in order to make the ion current additionally flowing as a leak current as small as possible with respect to the tunnel current, the portion other than the tip of the probe was covered with an insulating wax.

FIG. 4 shows the observation result of the gold substrate surface by this STM. At a bias voltage of +200 mV, the reaction current due to the electrochemical reaction hardly flows, a stable surface observation image is obtained, and Au grains are visible, but the surface shape is relatively flat and precipitates such as protrusions are present. I know that not.

Next, the tip of the Pt-Ir probe was fixed to a point on the gold substrate, and the distance between the probe and the substrate was set to the nm level to several levels.
In the state of 100 nm (for example, about 300 nm), the feedback circuit in the Z direction was turned off, the probe position was fixed, and a +4 V bias voltage was applied to the probe for 5 seconds.

After returning the bias voltage to +200 mV, the feedback circuit was restored and the processed area was set to 10
As a result of STM observation in the μm square area, as shown in FIG. 5, fine nickel cone-shaped dots with a diameter of 1000 nm and a height of 200 nm (dots that appear whitish in the figure) are deposited on the gold substrate. Was confirmed.

It is considered that this was obtained because the electrochemical reaction shown in Comparative Example 1 was locally caused because the gold substrate and the probe were extremely close to each other.

This deposition reaction occurred at a voltage Et> + 3V, which was the same as the critical voltage of Comparative Example 1, and the size of the fine dots could be controlled by controlling the bias voltage and the reaction time. Furthermore, by controlling the tunnel current before applying a voltage and reducing the distance between the working electrode (gold substrate) at the tip of the probe, it was possible to deposit fine dots with good controllability in a small area.

Further, it has been found that it is necessary to set the distance d between the tip of the electrode of the probe and the counter electrode to d <4 μm in order to deposit in a minute area. S in commercial solution
TM uses the 3-terminal method, but does not use the reference electrode 2
Similar results were obtained with the terminal method.

As described above, it is possible to produce fine dots of the above-mentioned magnetic element such as Ni or metal element in a solution using STM. Further, it is also possible to arrange the minute dots at an arbitrary place or periodically. For example, fine dots can be densely formed on the substrate by repeating the same operation as above while sequentially and intermittently moving the position of the probe by a predetermined distance. Using this microfabrication technology, it can be expected to be applied to fabrication of ultrafine elements and high-density recording devices.

Example 2 A gold substrate formed by depositing gold on a silicon substrate by a sputtering method,
Using a Pt-Ir probe, silver fine dots were formed on a gold substrate in the same manner as in Example 1 in silver perchlorate (mixed solution of 5 mM AgClO ₄ and 0.1 M HClO ₄ ). It was made.

After applying a bias voltage of +4.5 V to the probe for 5 seconds, the substrate surface is +200 mV around the processed place.
FIG. 6 shows the result of observation with the bias voltage (tunnel current: 10 nA). As in the case of nickel (Specific Example 1), it was confirmed that fine silver dots (portions raised in the form of small protrusions) were formed.

This deposition reaction occurred at a bias voltage of Et> + 4V, and the size of the deposited dots could be controlled by controlling the bias voltage and the reaction time.

Although the critical value of the bias voltage at which the precipitation reaction occurs is different from that in Example 1, its magnitude can be controlled by controlling the type and concentration of the electrolytic solution or changing the combination of the substrate and the probe. . Even in the case of fine silver dots, it is possible to easily arrange them in arbitrary places or periodically.

Example 3 A gold substrate formed by depositing gold on a silicon substrate by a sputtering method,
Using a Pt-Ir probe, in the same manner as in Example 1, in a copper sulfate solution (mixed solution of 5 mM CuSO ₄ and 0.1 M H ₂ SO ₄ ), copper micro dots were formed on the gold substrate. Was produced.

A bias voltage of +4 V was applied to the probe for 5 seconds, and then the substrate surface was +200 mV around the processed location.
FIG. 7 shows the result of observation with the bias voltage (tunnel current: 10 nA). Nickel (Specific Example 1), Silver (Specific Example 2)
It was confirmed that copper micro dots were formed in the same manner as in the above case.

As described above, from the specific example 3 (the same applies to the specific examples 1 and 2), this microfabrication technique can be used in all the systems (combinations of the electrolytic solution and the substrate) to which the conventional plating technique can be applied. it can.

Specific Example 4 In the copper sulfate solution used in Specific Example 3, with the tip of the Pt-Ir probe fixed at one point on the gold substrate, the feedback circuit in the Z direction was turned off, and the specific example 1 was applied to the probe. A bias voltage of -4 V (negative on the probe side) having a polarity opposite to that in the case of ~ 3 was applied for 5 seconds.

Thereafter, the bias voltage was returned to +200 mV, and the results of STM observation at a 10 μm square centering on the processed location are shown in FIGS. 8 and 9. From these figures, diameter 500
It was confirmed that nm holes were formed on the substrate surface.

This is formed by a so-called corrosion reaction due to a local electrochemical reaction of Au → Au ²⁺ + 2e ⁻ on the substrate because the gold substrate and the probe were very close to each other. Is considered to be.

This electrochemical reaction occurred at a bias voltage of Et <-4 V, and the size of the corrosion region could be controlled by controlling the bias voltage and the reaction time. Further, it has been found that the distance d between the probe and the substrate needs to be d <4 μm in order to corrode the minute area.

Although the copper sulfate solution was used as the liquid in the above-mentioned specific example 4, the same result can be obtained when the present invention is not limited to this and other acids such as HCl are used. In this case, for example, HCl does not act as an electrolytic solution but acts as a corrosive solution that dissolves Au ²⁺ described above.

In the method of Specific Example 4, it is possible to form a large number of recesses (holes) or grooves finely by continuously moving the probe and repeating the same operation.

Further, a film of a different material is formed on the upper surface of the concave portion or the convex portion formed by the operation described in the above-mentioned specific examples 1 to 4, and the concave portion or the convex portion is further formed thereon. By repeating the operation to form, three-dimensional structure,
That is, it is possible to obtain a highly integrated functional member having a surface layer having a multilayer structure.

That is, the microfabrication method shown in each of the above-described specific examples 1 to 4 and the ordinary processing method by film formation or etching (for example, the plating method and the etching method shown in Comparative Example 1) are repeated. By doing so, the three-dimensional artificial lattice, the fine wire structure, which is more complicated than the conventional artificial lattice material,
More complex structures, such as dot structures, can be made.

Here, a method for producing various film structures by applying the microfabrication method according to the present invention such as the specific examples 1 to 4 will be described with reference to FIGS.

FIG. 10 is a schematic view showing a procedure for forming a structure suitable for a three-dimensional artificial lattice film.

First, as shown in FIG. 10A, for example, Ni is deposited in the form of fine dots on the conductive substrate 31 by the fine processing method of the first embodiment based on the present invention using the above-described STM. A large number of objects 32 are formed. These deposits 32
Are formed, for example, in a grid pattern in a plan view, and a plurality of grooves 33 and a plurality of grooves 34 in a direction intersecting these grooves 33 are formed in parallel between each dot.

Next, based on the method of Comparative Example 1 described above,
As shown in FIG. 10B, a thin film 35 of another metal such as copper or platinum is formed on the entire surface. This thin film can be formed by another method such as DC sputtering or high frequency sputtering.

Next, again using the method of Example 1, FIG.
As shown in (d), a large number of dots 32 are formed on the thin film 35, and, for example, a three-dimensional artificial lattice film structure is produced.

However, after the step of FIG. 10B, a thin film 32 of Ni or the like is formed on the entire surface by the method of Comparative Example 1 as shown in FIG. , 34, and then
It is also possible to process a large number of dots 32 in (d). Of course, the dot 32 of FIG. 9A can also be manufactured by the method of the fourth specific example.

FIG. 11 is a schematic diagram showing the procedure for forming a two-dimensional artificial membrane structure.

First, as shown in FIG. 11A, a thin film 32 of nickel, for example, is formed on a substrate (eg, glass or plastic substrate) 31 by the DC sputtering method or the method of Comparative Example 1.

Next, as shown in FIG. 11 (b), a plurality of grooves 33 are formed in the nickel thin film 32 by the method of the fourth embodiment described above.
Are formed parallel to each other.

Next, as shown in FIG. 11 (c),
A thin film 35 of copper or platinum is formed on the entire surface in the same manner as above.

Next, as shown in FIG. 11 (d), a nickel stripe 32 is formed thereon in the same manner as described above, and then a plurality of grooves 33 are formed in the same manner as in the step of FIG. 11 (b). It is formed and processed as shown in FIG.

In this way, a two-dimensional artificial lattice film structure can be produced by sequentially repeating the above steps a required number of times.

The artificial lattice film structure manufactured as described above is used as a magnetic recording medium by forming the dots or stripes 32 with a magnetic material (for example, nickel) and the thin film 35 with a nonmagnetic material (for example, copper). If you do, both layers 32-35
Since the magnetic moment is oriented in a predetermined direction between them, various magnetic recordings are possible. Such a magnetic recording medium makes it possible to significantly improve the recording density by shortening the wavelength and narrowing the track.

For example, the three-dimensional artificial lattice film structure shown in FIG. 10D can change the spin directions of the magnetic dots 32 in the X, Y, and Z directions, and thus has various purposes as a magnetic recording medium and other device constituent parts. It is expected to be applicable to a wide range of application fields. Further, further improvement in performance such as prevention of crosstalk is expected.

The two-dimensional artificial lattice film structure of FIG. 11 (e) can change the spin direction of the magnetic thin film 32 in the Y direction and the Z direction as a magnetic recording medium similar to the above.

By the fine processing described above, for example,
As shown in FIG. 12 (a), a ridge 32 a (formed by processing the thin film 32) can be provided on the substrate 31 via an underlayer 42 (which is not always necessary). If the ridge 32a is formed as a magnetic thin film in a spiral shape, it can be used as a track of a floppy disk, but each track is completely separated and interaction (crosstalk etc.) between tracks is prevented. .

Further, as shown in FIG. 12 (b), instead of the above-mentioned magnetic convex strip 32a, a dot-shaped magnetic convex portion 32b is formed in the X direction,
When a large number of protrusions 32b are formed in the Y direction, the protrusions 32b can be selectively magnetized as individual recording magnetic domains, and the interaction between the protrusions 32b can be prevented in the track direction as well, which is more reliable. Such a fine structure is conveniently applied to a floppy disk, a magnetic tape, or a semiconductor device.

In addition, since fine processing enables ultra-precision control, it is suitable for providing a large number of fine pits on a substrate like a compact disc.

The microfabrication in each of the above-mentioned examples can be performed using one probe, but a plurality of probes can be provided as shown in FIG. That is, in FIG.
The rows are fixedly provided at positions (in the X direction in this example). In this example, by processing each probe 10 while scanning it in the Y direction, it is possible to form a plurality of parallel linear grooves 33 at the same time. This is shown in Figure 11.
It can also be applied to the steps of (b) and FIG. 12 (a).

In FIG. 13 (b), a plurality of probes 10 are arranged in a matrix at fixed intervals in the X and Y directions. In this example, by scanning each probe 10 separately in the X and Y directions by the size of the probe pitch, a large number of dot shapes shown in FIGS. 10 (a) and 12 (b) can be obtained. The convex portion 32 can be formed all at once.

FIG. 14 shows another microfabrication method based on the method of the present invention. That is, the convex portion 32c is formed in the concave portion 33 formed by the above-described method on the surface of the thin film 11, and such a surface structure is formed by the method of, for example, the specific example 4 described above, as shown in FIG. After providing the recess 33 so that
This can be easily formed by changing the polarity of the bias voltage and filling the other atom in the concave portion 33 to form the convex portion 32c as shown in FIG. .

Although the embodiments of the present invention have been described above, the following modifications are variously added based on the technical idea of the present invention or in consideration of the combination with the prior art. You can

For example, a liquid having no ionic conductivity is used as the liquid 9 described above, and a voltage of an appropriate magnitude is applied to cause a field evaporation phenomenon in the probe 8.
It is conceivable that the atoms forming the probe 8 are emitted and these are locally deposited on the surface of the workpiece located directly below the probe to form fine processing on the surface. Alternatively, by causing an electric field evaporation phenomenon locally on the surface of the workpiece located immediately below the tip of the probe, the local atoms are ejected and removed,
It is also conceivable to form minute recesses locally on the surface of the workpiece.

Further, as a conventional method for forming various structures in combination with the methods of the above-mentioned specific examples 1 to 4, there may be mentioned film forming methods such as the sputtering method and the plating method other than the method of the above-mentioned comparative example 1. It is also possible to leave the thin film in various patterns by a selective removal method of the thin film, for example, a usual etching technique, and to form fine dots or concave portions under or on the thin film by the method according to the present invention. Further, the present invention can be applied by treating the film by an electrolytic polishing method after forming the film.

Furthermore, various containers can be adopted as the container for containing the above-mentioned liquid, and in some cases, the workpiece itself can be used as the container.

In addition to the above-mentioned liquid, the material of the probe and the workpiece may be variously changed, and the method of operating the STM is not limited to the above. It is not necessary to perform the surface observation and the probe position control in the liquid, but it is possible to perform the process in a high vacuum as in the conventional case, and at the time of processing, supply the liquid to immerse the probe and apply a processing voltage.

[0100]

According to the present invention, since a machining voltage is applied between a probe of a scanning tunneling microscope and a workpiece to perform fine machining in a liquid, it is chemically stable against oxidation and the like. Under the conditions, it is possible to perform fine processing from the atomic level to the μm order without requiring a large-scale device such as a vacuum device.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view during fine processing according to an embodiment of the present invention.

2A is a partially enlarged view of FIG. 1 in a state where fine dots are formed by the same fine processing, and FIG. 2B is a partially enlarged view of FIG. 1 in which fine recesses are formed by the same fine processing. is there.

FIG. 3 is a schematic view of an STM device used for the fine processing.

FIG. 4 is a surface observation image by STM of a work piece adopted in this example.

FIG. 5 is an STM of a minute protrusion formed on the same workpiece.
It is the surface observation image by.

FIG. 6 is a surface observation image by STM of minute protrusions formed on another workpiece used in this example.

FIG. 7 is a surface observation image by STM of minute projections formed on another workpiece used in this example.

FIG. 8 is an STM surface observation image of a minute hole portion formed in a workpiece used in this example.

FIG. 9 is a surface observation image of the STM in which the minute hole portion is viewed two-dimensionally.

FIG. 10 is a schematic cross-sectional perspective view showing a procedure for producing a three-dimensional artificial lattice film structure by microfabrication in this example.

FIG. 11 is a schematic cross-sectional perspective view showing a procedure for producing a two-dimensional artificial lattice film structure by the fine processing.

FIG. 12 is a schematic cross-sectional perspective view illustrating a processing pattern of the same fine processing.

FIG. 13 is a schematic view for explaining another arrangement example of the STM probe and its operation during the same microfabrication (FIG. 13A is a sectional perspective view, and FIG. 13B is a plan view).

FIG. 14 is a schematic cross-sectional view showing another example of the same fine processing.

[Explanation of symbols] 9 ... Liquid (electrolyte) 10 ... Probe 11 ... Electrode 21 ... Container (O-ring) 23 ... Piezo element 24 ... Tunnel current power supply 25 ...・ X-direction scanning circuit 26 ・ ・ ・ Y-direction scanning circuit 27 ・ ・ ・ Z-direction drive / servo circuit 28 ・ ・ ・ Feedback circuit 32 ・ ・ ・ Fine dots 33 ・ ・ ・ Fine recesses 44 ・ ・ ・ Processing power supply

Claims (8)

[Claims] 1. A scanning tunneling microscope probe is used to apply a processing voltage between the probe and a workpiece in a liquid,
A fine processing method for performing fine processing on the workpiece. 2. The fine processing method according to claim 1, wherein an electrolyte solution is used as the liquid, and predetermined atoms are deposited in a fine pattern from the electrolyte. 3. The microfabrication method according to claim 1, wherein the workpiece is electrochemically corroded into a fine pattern. 4. The microfabrication method according to claim 1, wherein the distance between the probe and the workpiece is less than 4 μm. 5. The microfabrication is performed in a state where a feedback circuit of a probe position control mechanism for controlling a distance between a workpiece and a probe is opened to perform fine processing. Fine processing method. 6. The fine processing method according to claim 1, wherein the position control of the probe with respect to the workpiece is performed in a three-dimensional direction by a piezoelectric conversion element. 7. A step of performing fine processing on a workpiece by the fine processing method according to any one of claims 1 to 6,
The fine processing method according to any one of claims 1 to 6, wherein a normal film forming or processing step by etching is repeated. 8. A scanning tunneling microscope having a probe and a liquid storage portion, and a processing power supply for applying a processing voltage between the probe and a workpiece, according to claim 1. A microfabrication device used for carrying out the described microfabrication method.