JP2001004645A - Near field probe and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a near field probe and a manufacturing method thereof used for a near field microscope or a near field recording and playback device having a much smaller opening than the wavelength of light. SOLUTION: This method manufactures the probe used for a near field microscope or a near field recording and playback device, wherein electrolytic solution 32 brought into contact with a computer electrode 34 for applying voltage and a preform 10 (probe) formed out of a transparent material coated with a conductive shading coating are disposed so as to face each other, and brought into gradual contact with each other by driving a vertically moving stage 40 between them, and voltage is applied between the preform 10 and the counter electrode 34 by a voltage source 46 when the front end parts of the electrolytic solution 32 and the perform 10 (probe part 16) are brought into contact with each other, it is thus possible to remove the front end part of the preform 10 by electrolysis, and form an opening in the front end part thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a near-field light microscope,
The present invention relates to a near-field probe suitable for a near-field recording / reproducing apparatus and a method for manufacturing the near-field probe.

[0002]

2. Description of the Related Art A scanning probe microscope (SPM) detects an interaction between a probe (probe) and a sample when the probe is brought close to the sample surface to 1 μm or less.
It is a general term for a device that performs two-dimensional mapping of the interaction by scanning in the Y direction or the XYZ direction, and includes, for example, a scanning tunneling microscope (STM), an atomic force microscope (AFM), a magnetic force microscope (MFM), Includes a scanning near-field optical microscope (SNOM).

Among them, SNOM is an optical microscope having a resolution exceeding a diffraction limit by detecting an evanescent wave, particularly since the 1980s, as a method for measuring fluorescence of a biological sample, evaluating a photonics material, and evaluating an element (dielectric optical waveguide). It is being actively developed for applications to various characteristics evaluation, measurement of the emission spectrum of semiconductor quantum dots, evaluation of various characteristics of semiconductor surface light emitting devices, and the like. SNOM
Is a device for detecting a state of a light field (near field) near a sample by bringing a sharp probe close to the sample while irradiating the sample with light.

[0004] Betzi, dated December 21, 1993
U.S. Pat. No. 5,272,330 to G et al.
The evanescent field is generated in the vicinity of the minute opening of the probe tip by introducing light into the probe whose tip is thinned, the evanescent field is brought into contact with the sample, and the light generated by the contact between the evanescent field and the sample is converted to the sample. It discloses an SNOM that performs two-dimensional mapping of transmitted light intensity detected by a photodetector arranged below.

As a standard probe, a probe using an optical fiber made of silica glass is widely used. The tip of the SNOM probe heats the fiber and the pulling tip is thinned to a desired shape.
After that, when a metal is deposited from obliquely rearward while rotating the probe, the tip of the probe is hardly coated with the metal, so that the portion other than the tip is covered with the metal. At this time, a portion where the metal is not coated and an extremely thin portion of the metal film in the vicinity of the portion are minute openings. The device using this probe has improved lateral resolution compared to a device using a probe that is not coated with metal. Also, Van Hul
st et al., using a metal-coated probe, ion-cut a part of the tip to create a 20 nm aperture ("Appl. Phys. Lett. 72P. 3115").
(1998) ").

[0006] In order to obtain a high-resolution SNOM image, many studies have been made on optimizing the shape of a probe. In order to obtain a high-resolution SNOM image, it is desirable to use a probe that reduces the aperture at the tip of the probe and simultaneously converts the near-field light into propagation light with less loss of light. For example, the object part has developed a high-resolution probe with high propagation efficiency by sharpening an optical fiber by selective chemical etching in two steps ("IEEEPphotonics Tech").
oncology Letters, 10P. 99 (19
98) ").

Recently, Ono et al. Have produced a probe having an opening diameter of 150 nm by a silicon process ("IEEE P. 360 (1999)").

On the other hand, a principle experiment of optical recording using SNOM was first performed by Belizg et al.
l. Phys. Lett. 61P. 142 (199
2) "). In this principle experiment, a Pt / Co multilayer film, which is one of the magneto-optical media, was used, and the writing of the magnetic domain was performed using the above-described SN.
The magnetic domain was written by local heating by injecting pulsed light into the OM probe, and reading of written magnetic domains was performed by inputting polarized light to the probe and determining the polarization plane angle of the transmitted light from the back surface of the sample. By this method, writing and reading of a magnetic domain having a diameter of about 60 nm were successful. In addition, a principle experiment of optical recording using a phase change medium was also performed by Hosaka et al., And writing and reading of a phase change recording mark having a diameter of 60 nm were successfully performed (see “Jpn. J. Appl. Phys. 35”).
P. 443 (1996) ").

The recording method using SNOM has a problem that the transfer rate is low and the recording area is small. Ito and others
We made a slider-mounted optical head by processing a SNOM fiber probe, disclosed a rotary recording device, and tried to overcome this problem ("NFO-5 Proceedings"
P. 480 ").

[0010]

However, the probe according to the above method has the following disadvantages.

In forming a minute opening, a method of providing a minute opening with good reproducibility at the formed sharp tip has not been established. The method of forming a small aperture by oblique rear evaporation is limited to a straight optical fiber type probe. For example, in the case of a probe using a cantilever, it is difficult to apply evaporation to the tip of the probe. In addition, it is very difficult to control the aperture diameter with good reproducibility by cutting off a part of the tip by ion cutting or by removing the tip by colliding the tip with a glass plate. However, there is a problem that it is difficult to obtain a small opening diameter.

The present invention has been made in view of the above-mentioned circumstances, and a near-field probe and a near-field probe used in a near-field microscope or a near-field recording / reproducing apparatus having an aperture smaller than the wavelength of light. It is an object of the present invention to provide a probe manufacturing method.

[0013]

According to the present invention, there is provided a probe used for a near-field microscope or a near-field recording / reproducing apparatus, in which a probe made of a transparent material is coated with a conductive light-shielding film. Is removed by electrolysis to form an opening.

The present invention also relates to a method for manufacturing a probe used in a near-field microscope or a near-field recording / reproducing apparatus, comprising the steps of coating a probe made of a transparent material with a conductive light-shielding film; Forming an opening by removing the tip portion by electrolysis.

The present invention also relates to a method for manufacturing a probe used in a near-field microscope or a near-field recording / reproducing apparatus, comprising the steps of: coating a probe made of a transparent material with a conductive light-shielding film; And a step of applying a voltage between the electrode and the probe and a step of applying a voltage between the probe and the electrode.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. In the method for manufacturing a near-field probe according to the present invention, first, a cantilever having a free-end probe that transmits light made of a transparent material is prepared. This cantilever is used, for example, in a scanning near-field light microscope incorporating an atomic force microscope proposed by Van Forst et al. Next, a conductive light-shielding coat is provided on the surface of the probe portion of the cantilever to obtain a preform. For this preformed product, the conductive light-shielding coat at the tip of the probe part was removed by electrolysis to create an opening,
A cantilever for a scanning near-field optical microscope and a head for optical recording / reproducing are obtained as finished products.

Hereinafter, embodiments of the present invention (first embodiment,
The second embodiment will be described with reference to the drawings.

(First Embodiment) First, a probe for a scanning near-field microscope used in the following first embodiment,
FIG. 1 shows a preform of an optical recording / reproducing head.
This will be described with reference to FIG.

The preformed product 10 has a lever portion 12 made of silicon nitride fixed to a support portion 14 and a probe portion 16 formed at a tip portion thereof. A conductive light-shielding coat 18 is formed on the entire lower surface of the lever portion 12. The conductive light-shielding coat 18 may be anything as long as it is conductive and blocks light. For example, a film of gold, platinum palladium, aluminum, titanium or the like can be given. The thickness of the film is such that the light intensity attenuates to 1 / e ² in consideration of light leakage, ie, 4
0-100 nm is required. Note that the substances exemplified here are all metals, but are not limited to metals.

In the first embodiment, a part of the conductive light-shielding coat 18 covering the tip of the probe part 16 is removed by electrolysis from the preformed product 10 as shown in FIG. Then, a near-field probe in which a fine opening 22 is incorporated at the tip of the probe portion 16, that is, a near-field microscope probe or an optical recording / reproducing head is obtained.

Next, as a first embodiment, a preformed product 1
An apparatus for forming a minute opening 22 to zero and a method for manufacturing a near-field probe thereof will be described.

FIG. 2 shows the configuration of a near-field probe manufacturing apparatus for forming a minute opening 22 in the preform 10. As shown in FIG. 2, the near-field probe manufacturing apparatus is provided with a holding unit 30 for holding the preform 10 at the support unit 14. The preform 10 (probe section 16) held by the holding section 30 is held at a position facing the counter electrode 34 via the electrolyte solution 32.

The electrolyte solution 32 is made of, for example, potassium chloride or sulfuric acid, and is dropped and mounted on the counter electrode 34. As the counter electrode 34, for example, platinum or copper whose surface is well polished is used. The counter electrode 34 is exchangeably fixed on the counter electrode holding insulator 36.
The counter electrode holding insulator 36 is fixed on a stage table 38. The stage table 38 is used for the preform 10
Is fixed to a vertical movement stage 40 which is a means for adjusting the distance between the probe section 16 and the counter electrode 34. Vertical stage 40
Moves up and down according to a signal from the stage drive unit 42,
The distance between the probe portion 16 of the preform 20 and the counter electrode 34 is adjusted. As the vertical movement stage 40, for example, a piezoelectric body or a motor is used. The counter electrode 34 is connected to one terminal of a voltage source 46 for supplying a constant voltage or a constant current, and the conductive light-shielding coat 18 of the preform 10 is connected to the other terminal of the voltage source 46 via an ammeter 44. Connected to terminal. Voltage source 46
For example, a potentiostat galvanostat is used.

Next, using the near-field probe manufacturing apparatus shown in FIG.
The method of forming 2 will be described. First, the holding unit 30
The vertical movement stage 40 is positioned so that a predetermined distance is provided so that the probe portion 16 of the preform 10 and the electrolyte solution 32 do not come into contact with each other in this state. When a constant voltage is applied by the voltage source 46, the ammeter 44 detects "0" amperage because the preform 10 is insulated.

Next, a signal is transmitted from the stage drive section 42 to the up / down stage 40 so that the up / down stage 4
0, the stage table 38 is moved upward, and the distance between the probe section 16 of the preform 10 and the electrolyte solution 32 is gradually reduced. When the probe section 16 and the electrolyte solution 32 come into contact with each other, conduction is established, and the current value detected by the ammeter 44 increases. Here, the drive of the vertical movement stage 40 is stopped.

Subsequently, when the voltage source 46 is reset so that a constant current flows, the conductive coat 18 covering the probe portion 16 starts to gradually peel off from the tip portion of the probe portion 16, and FIG. The opening 22 shown in FIG. As a result, a probe for a near-field microscope or a head for optical recording / reproducing having a minute opening 22 at the tip of the probe section 16 is obtained.

Next, adjustment of the opening 22 formed in the preform 10 using the near-field probe manufacturing apparatus will be described. The probe 16 and the counter electrode 34 in the electrolyte solution 32
When a voltage is applied between the tip and the tip, the sharper the current flow is, the more the conductive light-shielding coat 18 at the tip of the probe 16 is specifically ionized and peeled off. The opening diameter also depends on the shape of the tip of the probe, but if the cantilever is in the same lot manufactured by the silicon process, it can be considered that the tip shape is almost the same.

The opening diameter is adjusted by adjusting the amount of electricity, which is the product of the amount of electrolysis current and the time, the material of the conductive light-shielding coat 18,
This is done by adjusting the thickness. However, if the electrolysis is instantaneously performed with a large amount of current, the effect of gas and convection generated during the reaction occurs and the opening becomes asymmetric. Therefore, the electrolysis is performed at a low current.

In the near-field probe manufacturing apparatus shown in FIG. 2, all of the electrolyte solution 32 is mounted on the counter electrode 34 and does not contact the counter electrode holding insulator 36. 3, it is also possible to adopt a configuration in which the electrolyte solution 32 is placed on the counter electrode holding insulator 36, and the counter electrode 341 is in contact with a part thereof.

In the above description, the preformed product 10
Although the distance between the (probe section 16) and the counter electrode 34 is adjusted by moving the counter electrode 34 up and down by controlling the vertical movement stage 40, the holding section 30 may be moved up and down.

In this manner, by removing the probe portion 16 covered with the conductive light-shielding coat 18 by electrolysis, a fine opening 22 can be provided with good reproducibility.

(Second Embodiment) Next, a second embodiment of the present embodiment will be described. Here, the same preformed product 10 used in the first embodiment is used. FIG. 4 shows a configuration of a near-field probe manufacturing apparatus for forming a minute opening 22 in the preform 10 according to the second embodiment. In FIG. 4, the same components as those of the near-field probe manufacturing apparatus according to the first embodiment shown in FIG. 2 are denoted by the same reference numerals, and detailed description thereof will be omitted.

In the near-field probe manufacturing apparatus according to the second embodiment, a laser light source 50 and a two-segment photodetector 52 are installed above the preform 10 held by the holding unit 30. The laser light source 50 and the two-piece photodetector 52 constitute an optical lever type displacement measuring means, and monitor the displacement of the lever portion 12 of the preformed product 10, that is, the distance between the probe portion 16 and the counter electrode 34. I can do it.

The conductive light-shielding coat 18 coated on the lever portion 12 functions as a reflection surface for displacement measurement by an optical lever method, which reflects a laser beam emitted from the laser light source 50. The laser beam reflected by the conductive light-shielding coat 18 is detected by a two-segment photodetector 52 and used for displacement measurement.

The counter electrode 34 is connected to one terminal of a voltage source 461 for supplying a constant current, and the conductive light-shielding coat 18 of the preform 10 is connected to the other terminal of the voltage source 461. As the voltage source 461, for example, a galvanostat that supplies a constant current is used.

Next, a method for forming a minute opening 22 at the tip of the probe portion 16 of the preform 10 using the near-field probe manufacturing apparatus shown in FIG. 4 will be described. First, the preform 10 is held by the holding unit 30, and in this state, the vertical movement stage 4 is moved so that a predetermined distance is provided so that the probe 16 and the electrolyte solution 32 do not come into contact with each other.
The position of 0 is determined.

Next, the force curve shown in FIG. 5 is measured as in the case of the atomic force microscope. That is, FIG.
As shown in FIG. 6A, the vertical movement stage 40 is driven to gradually bring the probe unit 16 and the counter electrode 34 and the electrolyte solution 32 apart from each other, as shown in FIG. The probe section 16 is brought into contact with the electrolyte solution 32, and the displacement of the probe section 16 during this series of operations is monitored using an optical lever type displacement measuring means. The force curve shown in FIG. 5 can be obtained by drawing a graph with the distance between the sensor and the counter electrode 34 and the output of the displacement measuring means on the vertical axis.

Based on the obtained force curve, only the tip of the probe 16 is brought into contact with the electrolyte solution 32.
That is, the distance between the probe 16 and the counter electrode 34 is
The force curve shown in FIG. 5 is set to be at the position (4).

Subsequently, when the voltage source 46 is set to allow a constant current to flow, the conductive coat 1 covering the probe 16 is
8 starts to be gradually peeled off from the tip of the probe portion 16, and FIG.
The opening 22 shown in (b) is formed. As a result, a probe for a near-field microscope or a head for optical recording / reproducing having a minute opening 22 at the tip of the probe section 16 is obtained.

In this way, the distance between the probe 16 and the counter electrode 34 (the electrolyte solution 32) is monitored by measuring the force curve in the same manner as in the case of the atomic force microscope. When a constant current flows through the voltage source 46 when the electrolyte solution 32 comes into contact with the electrolyte solution 32 (the position indicating the displacement in FIG. 5B), the tip of the probe 16 is electrolyzed to form the minute opening 22. Can be provided.

[Appendix 1] This is a near-field probe manufacturing method for manufacturing a probe used in a near-field microscope or a near-field recording / reproducing apparatus, which is coated with an electrolytic solution in contact with a voltage application electrode and a conductive light-shielding film. A probe made of a transparent material is disposed so as to oppose, the distance between the electrolytic solution and the probe is gradually approached, and the probe and the probe are contacted when the electrolytic solution and the tip of the probe come into contact with each other. A method for manufacturing a near-field probe, comprising: applying a voltage between an electrode and an electrode to remove an end portion of the probe by electrolysis to form an opening in the end portion.

[Supplementary Note 2] In the near-field probe manufacturing method according to Supplementary Note 1, a relative distance between the probe and the electrolytic solution accompanying the approach of the electrolytic solution and the probe is detected, and the electrolyte solution is detected. Applying a voltage when contact between the probe and the tip of the probe is detected.

[Appendix 3] A near-field probe manufacturing apparatus for manufacturing a probe used in a near-field microscope or a near-field recording / reproducing apparatus, comprising: an electrolytic solution in contact with a voltage application electrode; and a conductive light-shielding film. Holding means for holding a probe made of a transparent material so as to face the electrolytic solution, moving means for gradually bringing the electrolytic solution and the probe closer to each other, and the electrolytic solution by the moving means. Applying means for applying a voltage between the probe and the electrode when the tip portion of the probe is in contact with the probe, removing the tip portion of the probe by electrolysis, and opening the tip portion. An apparatus for producing a near-field probe, comprising:

[0044]

As described above in detail, according to the present invention, in a probe used for a near-field microscope or a near-field recording / reproducing apparatus, a probe made of a transparent material is coated with a conductive light-shielding film. Since the opening is formed by electrolytically removing the tip of the probe, it is possible to provide a near-field probe used in a near-field microscope or a near-field recording / reproducing apparatus having a small opening compared to the wavelength of light. Become.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of a configuration of a preform 10 and a cantilever 20 for a scanning near-field optical microscope.

FIG. 2 is a diagram showing a configuration of a near-field probe manufacturing apparatus for forming a minute opening 22 in a preform 10 according to the first embodiment.

FIG. 3 is a diagram illustrating a configuration of another near-field probe manufacturing apparatus according to the first embodiment.

FIG. 4 is a diagram showing a configuration of a near-field probe manufacturing apparatus for forming a minute opening 22 in a preform 10 according to a second embodiment.

FIG. 5 is a diagram showing an example of a force curve.

FIG. 6 is a view for explaining a positional relationship between a preform 10 and an electrolyte solution 32.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Pre-molded product 12 ... Lever part 14 ... Support part 16 ... Probe part 18 ... Conductive light shielding coat 20 ... Scanning near-field light microscope cantilever 22 ... Opening 30 ... Holding part 32 ... Electrolyte solution 34, 341 ... Counter electrode 36 ... Counter electrode holding insulator 38 ... Stage table 40 ... Vertical movement stage 42 ... Stage drive unit 44 ... Ammeter 46 ... Voltage source 50 ... Laser light source 52 ... Two-part split photodetector

Continued on the front page (72) Inventor Nobushi Atoda 1-1-4 Higashi, Tsukuba City, Ibaraki Pref., National Institute of Advanced Industrial Science and Technology (72) Inventor Yoshimasa Suzuki 2-43-2 Hatagaya, Shibuya-ku, Tokyo Olympus Optical Co., Ltd. F-term (reference) 5D119 AA11 JA34 NA05

Claims (3)

[Claims] 1. A probe used in a near-field microscope or a near-field recording / reproducing apparatus, wherein a probe made of a transparent material is coated with a conductive light-shielding film, and a tip portion of the probe is removed by electrolysis to form an opening. A near-field probe characterized by forming: 2. A method for manufacturing a probe used in a near-field microscope or a near-field recording / reproducing apparatus, comprising: coating a probe made of a transparent material with a conductive light-shielding film; Forming an opening by electrolysis. 3. A method for manufacturing a probe used in a near-field microscope or a near-field recording / reproducing apparatus, comprising: coating a probe made of a transparent material with a conductive light-shielding film; A method for manufacturing a near-field probe, comprising: a step of bringing a liquid into contact with an electrolyte; and a step of applying a voltage between the electrode and the probe.