JP2002162332A - Method for producing near-field optical probe, apparatus for producing near-field optical probe, and near-field optical probe, near-field optical microscope, near-field optical fine processing apparatus, and near-field optical recording / reproducing apparatus - Google Patents

Abstract

[PROBLEMS] When a near-field optical probe is bent by irradiating a laser beam, the tip of the probe is prevented from being melted and rounded by the irradiated laser beam, and a near-field with high resolution is provided. Near field optical probe manufacturing method and near field optical probe manufacturing apparatus capable of manufacturing optical probe, near field optical probe, near field optical microscope, near field optical fine processing apparatus, near field optical recording / reproducing apparatus I will provide a. An irradiation part is melted by irradiation with laser light,
In a method for producing a near-field optical probe, which performs a bending process so as to bend a tip portion having a probe with respect to a root portion, to produce a near-field optical probe, wherein the near-field optical probe is irradiated with the laser light. The bending process is performed so that the laser beam is irradiated from an angle shifted from the vertical direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a near-field optical probe, an apparatus for manufacturing a near-field optical probe, a near-field optical probe, a near-field optical microscope, a near-field optical fine processing apparatus, and a near-field optical recording / reproduction. It concerns the device.

[0002]

2. Description of the Related Art In recent years, STM (scanning tunneling microscope)
With the development of SPM (scanning probe microscope) technology, which is represented by AFM (atomic force microscope), the resolution of the microscope is increased by bringing the probe with a sharpened tip closer to the sample to a distance of 100 nm or less. It has become possible to observe atomic and molecular sizes. As for light, as a family of SPMs, a near-field optical microscope (hereinafter abbreviated as SNOM) [EP0112] for examining the surface state of a sample using evanescent light oozing from a minute aperture at the tip of a sharp optical probe.
401, Durig et al. Appl. Phys. vo
l. 59, p. 3318 (1986)] or a photon STM (hereinafter, referred to as a probe) in which light is made incident from the back surface of a sample via a prism under the condition of total reflection, and near-field light seeping onto the sample surface is detected from the sample surface with an optical probe to inspect the sample surface. PSTM
[Reddick et al., Phys. Rev .. B
vol. 39, p. 767 (1989)]. By using the SNOM, it is possible to access a minute area of 100 nm or less and detect optical information. As a method of manufacturing an optical probe used for SNOM, a method has been proposed in which an optical fiber is chemically etched and the tip of the optical fiber is sharpened by utilizing a difference in etching rate due to a difference in material between a core and a clad. JP-A-5-241076). Also, a method has been proposed in which a portion of an optical fiber or a pipette is melted by heating with a heater, irradiating a laser beam, or discharging while a pipette is stretched, and is sharpened by stretching (US Pat. No. 49174).
62 specification). Now, in the SNOM, the position of the tip of the optical probe is determined by the influence of the near-field light on the sample surface.
Several methods have been proposed for controlling the distance to 0 nm or less. In the first method, the optical probe is vibrated in a direction parallel to the sample surface, and a shear force, which is a lateral van der Waals force acting between the tip of the optical probe and the sample surface, is detected, and this is fixed. This is a shear force method that performs distance control to maintain the distance. The second method uses an cantilever-type optical probe as an optical probe, detects van der Waals force or interatomic force acting between the tip of the optical probe and the sample surface, and performs an AFM that performs distance control to keep the force constant. It is a method. Here, as a cantilever type optical probe used in the AFM method,
A method has been proposed in which the tip of the pipette or optical fiber is processed to form an optical micro opening at the tip of the projection, and the pipette or optical fiber is bent by irradiating CO ₂ laser light or the like to have a function as a cantilever. (U.S. Pat. No. 5,679,978;
174542).

[0003]

However, the above-mentioned method for manufacturing an optical probe in which a sharpened optical fiber or pipette is bent to form a cantilever has the following problems. FIG. 8 shows an example in which a sharpened optical fiber (thinned optical fiber 801) is horizontally supported during CO ₂ laser irradiation. In FIG. 8, when the CO ₂ laser beam 802 is irradiated to a position slightly short from the tip of the thinned optical fiber 801 supported horizontally, the laser beam irradiation position 805 is melted and bent upward in the figure. As a result,
The sharpened tip 803 in the chemical etching in the previous step enters the irradiation range of the CO ₂ laser beam, and the sharpened tip melts to form a rounded tip 804. As a result, the diameter of an opening formed in an opening forming step to be described later becomes large, and the resolution as a near-field optical probe is reduced.

In view of the above, the present invention solves the above-mentioned problems in the prior art. When a near-field optical probe is bent by irradiating a laser beam, the tip of the probe is melted and rounded by the irradiated laser beam. Near-field optical probe manufacturing method and near-field optical probe manufacturing apparatus, near-field optical probe, near-field optical probe, near-field optical microscope, near-field light It is an object of the present invention to provide a fine processing device and a near-field optical recording / reproducing device.

[0005]

In order to achieve the above object, the present invention provides a method for manufacturing a near-field optical probe and an apparatus for manufacturing a near-field optical probe configured as described in the following (1) to (12). And a near-field optical probe, a near-field optical microscope, a near-field optical fine processing device, and a near-field optical recording / reproducing device. (1) A method for producing a near-field optical probe in which an irradiated portion is melted by irradiating a laser beam and a tip portion having a probe is bent at a predetermined angle to a root portion to produce a near-field optical probe. The near-field optical probe, wherein the near-field optical probe performs bending processing so as to receive the irradiation of the laser light from a shifted angle with respect to a vertical direction which is the irradiation direction of the laser light. Production method. (2) The method for manufacturing a near-field optical probe according to the above (1), wherein a bending stopper is arranged in the bending process to limit a bending angle of the near-field optical probe. (3) In an apparatus for producing a near-field optical probe, comprising a bending processing means for melting an irradiated portion by laser light irradiation and bending a tip portion having a probe with respect to a root portion at a predetermined angle, wherein the bending processing means is Having support means for supporting the near-field light probe at an angle shifted from a vertical direction which is the irradiation direction of the laser light, and the near-field light probe supported by the support means has a direction in which the laser light is irradiated. An apparatus for manufacturing a near-field optical probe, wherein the apparatus is configured to receive irradiation of the laser light from a shifted angle. (4) The near-field light according to (3), wherein the bending means includes a bending stopper, and the bending stopper limits a bending angle of the near-field optical probe. Probe manufacturing equipment. (5) The method for producing a near-field optical probe according to any one of (1) and (2), or the method for producing a near-field optical probe according to any one of (3) and (4). Forming a light-shielding material on the tip portion and the root portion bent by the bending process using a near-field optical probe, wherein a first film-forming process on the tip portion and a second film-forming process on the root portion are performed. When forming a film in each of these film forming steps, the probe is rotated around different axes, and a film is formed on the probe surface from a direction perpendicular to the rotation axis using a light shielding material. A method for producing a near-field optical probe. (6) In the first film forming step, an angle for supporting a root portion of the near-field optical probe with respect to a direction perpendicular to the rotation axis is set when the apparatus is mounted on an apparatus using the near-field optical probe. (5) The method for producing a near-field optical probe according to the above (5), wherein an angle formed by a root portion of the near-field optical probe with respect to a sample surface facing the tip of the near-field optical probe. (7) The method for producing a near-field optical probe according to any of the above (1) and (2), or the apparatus for producing a near-field optical probe according to any of the above (3) and (4), or the above (5) A near-field optical probe produced by the method for producing a near-field optical probe according to any one of (5) and (6). (8) With the near-field optical probe according to (7),
The tip of the near-field light probe is supported on the substrate such that it is the free end of the cantilever, while the other end of a rod-shaped member different from the near-field light probe having one end supported by the substrate is connected to the proximity A near-field light probe which is joined to a vicinity of a tip of the field light probe so that a V-shape is formed by the near-field light probe and the rod-shaped member. (9) using the near-field optical probe described in (7) above, supporting the near-field optical probe on a substrate such that the tip of the near-field optical probe is the free end of the cantilever; When joining one end of the rod-shaped member to the vicinity of the tip of the near-field optical probe, joining the rod-shaped member to the near-field optical probe so that the angle formed by the rod-shaped member becomes a predetermined angle; and Supporting the other end of the rod-shaped member. (10) In a near-field optical microscope for observing a sample surface with a near-field optical probe, the near-field optical probe is replaced with the near-field optical probe according to any one of (7) to (8) or (9). A near-field optical microscope comprising a near-field optical probe manufactured by the above-described method for manufacturing a near-field optical probe. (11) In a near-field light microfabrication apparatus for finely processing a surface to be processed by a near-field light probe, the near-field light probe may be the near-field light probe according to any one of the above (7) to (8), or A near-field light microfabrication device comprising a near-field light probe manufactured by the method for manufacturing a near-field light probe according to (9). (12) In the near-field optical recording / reproducing apparatus for recording / reproducing information by using the near-field optical probe, the near-field optical probe may be the near-field optical probe according to any one of (7) to (8), or A near-field optical recording / reproducing apparatus comprising a near-field optical probe manufactured by the method for manufacturing a near-field optical probe described in 9).

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In an embodiment of the present invention,
By applying the above configuration of the present invention, when the processing beam irradiation portion is melted and the bending process of the cantilever type near-field optical probe is performed, the angle at which the near-field optical probe is shifted from the perpendicular with respect to the processing beam irradiation direction. By performing the processing beam irradiation, it is possible to avoid rounding of the tip due to melting, and it is possible to manufacture a near-field optical probe with high resolution.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing a configuration of a near-field optical probe according to an embodiment of the present invention, and shows a cross section of the near-field optical probe cut along a plane including a central axis of the probe.
In FIG. 1, reference numeral 101 denotes a thinned optical fiber A having a cylindrical rod shape having a diameter of 20 μm, and reference numeral 102 denotes a thinned optical fiber B also having a cylindrical rod shape having a diameter of 20 μm.

The tip of the thinned optical fiber A101 is sharpened to a conical shape with a radius of curvature of 1 μm or less, and the probe 10
3. Around the thinned optical fiber A101, a film thickness of 150
A nm light-shielding Al coating 104 is applied.
A small opening 105 having a diameter of 100 nm or less is provided at the tip of the probe 103. One end of the thinned optical fiber B102 is bonded to the vicinity of the distal end of the thinned optical fiber A101 with an adhesive B106 to form a bonded portion 107. The root portion of the thinned optical fiber A101 is fixed to the optical probe support substrate 108 with an adhesive A109. The other end of the thinned optical fiber B102 on the side opposite to the joint 107 is attached to the optical probe support substrate 108 with an adhesive C110.
It is fixed at.

With the above configuration, the thinned optical fiber A1
By causing an elastic deformation in the x direction shown in the figure at 01, the probe 103 at the tip can be displaced in the x direction. However, since the thinned optical fiber B102 is joined in a V-shape, the amount of elastic deformation in the y direction decreases, and the amount of displacement of the probe 103 in the y direction can also be reduced.

As a specific numerical example, the diameter is 20
The material of the thinned optical fiber A101 and the thinned optical fiber B102 of μm is quartz, and the optical probe support substrate 10
8, the length from which the thinned optical fiber A101 and the thinned optical fiber B102 protrude is 500 μm,
Thinned optical fiber A101 and thinned optical fiber B102
Is 45 °, when a force is applied to the tip of the near-field optical probe, the elastic constant of the tip in the x direction is 20 N / m, whereas the elastic constant of the tip in the y direction is It becomes 20,000 N / m and becomes 1000 times harder. Therefore, when a similar force is applied, the probe 103
It can be seen that the displacement in the y direction is much smaller than the displacement in the x direction of the portion.

The root of the thinned optical fiber A101 is
The optical fiber 111 is connected to the original optical fiber 111 before being thinned, and the near-field light can be generated from the minute aperture 105 by making the light 112 incident from the end of the original optical fiber 111. In addition, the intensity of the near-field light can be detected by emitting the propagating light obtained by converting the evanescent light detected by the minute aperture 105 in the thinned optical fiber A101 from the end of the original optical fiber 111. .

Next, a method of manufacturing a near-field optical probe in this embodiment will be described with reference to FIGS. FIG. 2 is a diagram illustrating a process of thinning an optical fiber by using chemical etching. About 10 mm from the tip of the optical fiber 203 cleaved into the end face having a length of about 50 mm is immersed in the etching solution 202 in the Teflon (registered trademark) container 201. The configuration of the optical fiber used here is as follows. Cladding 204 diameter is 125 μm, core 205 diameter is 2
0 μm, the cladding material is pure quartz, and the core material is pure quartz doped with GeO ₂ at a concentration of 16 mol%.

The composition of the etching solution 202 is NH ₄ F
(40% aqueous solution): HF (50% aqueous solution): H ₂ O = 1
0: 1: 1. Optical fiber 203 is etched with etchant 2
02, the cladding and core of the infiltrated portion are etched, and the optical fiber 209 in the middle of the etching in the figure is etched.
As shown in (1), the core tip becomes sharper as the clad diameter becomes smaller. This is because when quartz is etched,
(1) The core portion doped with GeO ₂ has a lower etching rate than the clad portion, and (2) since the optical fiber is formed by stretching, it differs in the stretching direction and the direction perpendicular thereto. Anisotropy occurs and the etching rate differs between the stretching direction and the vertical direction. About 10 hours after the start of the etching, the clad portion disappears due to the etching, the core portion is exposed (the core exposed portion 206), and only the core portion sharpened conically (the sharpened portion 208) remains. The state at this time is shown in the optical fiber 207 at the end of the etching in the figure.

Through the above steps, a thinned optical fiber having a conical tip shape having a core exposed portion 206 having a diameter of 20 μm and a sharpened portion 208 having a radius of curvature of 1 μm or less can be obtained. Since this thinned optical fiber is composed of only the core portion of the original optical fiber, when the original optical fiber is of the step index (SI) type, the core material is made of a homogeneous material and the tip is conical. Become. Also, when the original optical fiber is a graded index (GI) type, the core material has a gradual change in the component composition ratio from the center to the outer periphery, and the tip is almost conical but slightly displaced. Becomes

As described above, the thinned optical fiber obtained by etching until the core is exposed can form a substantially conical probe at the tip, and the boundary between the probe root and the side of the thinned optical fiber. There is no plane perpendicular to the central axis in the vicinity. For this reason, the metal film for shielding from the lateral direction described below does not reduce the thickness of the portion other than the portion where the fine opening is formed at the tip, and eliminates unnecessary leakage light. Further, since thinning and sharpening can be performed in a single step, an etching solution having a plurality of compositions is not used in multiple steps, and the cost is reduced.

Next, a method of forming a near-field optical probe having an optical aperture at the tip of an optical fiber in this embodiment will be described. As shown in FIG. 3, an Al vapor deposition 302 is performed on the thinned optical fiber 301 from the lateral direction while rotating the optical fiber 301 about a central axis 303, thereby forming a 150 nm thick light shielding Al film 305. The distal end of the thinned optical fiber 301 is a spherical surface having a radius of curvature of 1 μm or less. On the other hand, when metal deposition is performed from the lateral direction, the thickness of the distal end becomes thinner than that of the side surface. 304 is formed. At this time, the size of the opening is substantially the same as the radius of curvature of the tip. After forming the near-field optical probe in this way, a sufficiently long optical fiber is fusion-spliced to the end of the thinned optical fiber opposite to the probe, and through this optical fiber, a near-field optical probe is formed. Takes light in and out when used.

Next, a description will be given of an example of a configuration for preventing the lateral displacement of the tip of the probe when scanning the probe using the near-field light probe formed as described above. Conventionally, when an optical probe manufactured by sharpening an optical fiber or a pipette is used for the distance control of the shear force method, the following problem occurs.
First, in the distance control of the shear force method as shown in FIG. 17A, a piezo element 1703 is attached to an optical probe 1702 whose tip is arranged close to the sample surface 1701, and the optical probe 1702 is vibrated in the x direction in the figure. . At this time, ideally, the tip of the optical probe reciprocates in the x direction as indicated by the arrow shown in FIG. 17B as viewed from the sample side. However, since an optical probe manufactured by sharpening an optical fiber or a pipette is cylindrical, x
The elastic constant for the deflection in the y-direction is the same as the elastic constant in the y-direction. Therefore, a vibration component in the y direction is excited while vibrating in the x direction, and the tip of the optical probe rotates in an elliptical shape as shown in FIG. 17C, or a figure of eight as shown in FIG. Exercise in shape. For this reason, the tip of the optical probe is displaced in the y direction, and the position resolution of observation, processing, and recording using SNOM is reduced.

An optical probe prepared by sharpening an optical fiber or a pipette and further forming a cantilever is brought into contact with the tip of the probe to the sample surface, and is used for distance control of a contact mode AFM system for detecting repulsive force of van der Waals force. If so, the following problems occur. As shown in FIG. 18, which is a view of a cantilever-type optical probe whose tip is arranged close to the sample surface as viewed from the surface opposite to the sample surface, the optical probe is scanned in the + y direction. The tip receives a frictional force from the sample surface and bends in the −y direction opposite to the scanning direction. For this reason, the tip of the optical probe is displaced in the -y direction, and the positional resolution of observation, processing, and recording using SNOM is reduced.

On the other hand, as in this embodiment, another thinned optical fiber is joined so that a V-shape is formed near the tip of the thinned optical fiber formed as described above. It is possible to prevent lateral displacement of the tip of the probe. Specifically, a thinned optical fiber A manufactured as described above using the apparatus shown in FIG.
401 and another optical fiber B402, which is similarly thinned using chemical etching, is joined in a V-shape. First, the thinned optical fiber A401 is fixed to the probe support substrate 403 using the adhesive A404. Next, the thinned optical fiber B402 is temporarily fixed to the xyzθ stage 405 with a tape 406, and an adhesive B407 is applied to the tip of the thinned optical fiber B402. Lastly, the xyz stage 405 is driven while monitoring using a microscope or a video camera from two directions, the z direction and the y direction in the figure, to form a predetermined angle near the tip of the thinned optical fiber A401, and the adhesive is formed. Thinned optical fiber B4 coated with B407
Positioning is carried out so that the tip of 02 comes, and bonding is performed. After the adhesive B407 has sufficiently hardened, the tape 4
06 is peeled off, and the thinned optical fiber B402 is fixed to the probe support substrate 403 using an adhesive C408.

Here, an example of an apparatus for performing V-shaped joining using an adhesive has been described. In addition to this, a joining portion is provided between two needle-like electrodes facing each other to form two needle-like electrodes. Discharge may be performed in the interim, and bonding may be performed by discharge fusion. Also,
The bonding may be performed by irradiating a CO ₂ laser beam to the bonding portion and performing laser fusion.

FIG. 5 shows the configuration of a near-field optical microscope of the shear force distance control type using the V-shaped near-field optical probe manufactured by the above steps. In FIG. 5, a probe support substrate 5 for supporting a V-shaped near-field optical probe 501 is provided.
02 is attached to the piezo element 503, and a sine wave signal is applied from the function generator 504 to vibrate in the x direction in the figure. At this time, if the frequency of the sine wave signal is made to match the resonance frequency related to the deflection of the V-shaped near-field optical probe 501 in the x direction, the near-field probe 50
One tip resonates. Near-field optical probe 5 in this resonance state
The laser B 505 irradiates the laser beam from the laser B 505 in the vicinity of the tip 01 in the y direction, and the position change of the transmitted light beam spot is detected by the split sensor 506. The output signal is output.

On the other hand, the surface of the sample 508 mounted on the xyz stage 507 is brought close to the tip of the V-shaped near-field optical probe 501 to a distance of 100 nm or less. At this time, a shear force (Van der Waals force) acts between the tip of the near-field optical probe 501 and the surface of the sample 508, and the amplitude of the vibration of the tip of the near-field optical probe 501 decreases. The amplitude of this vibration is detected by the lock-in amplifier 509 based on the difference signal of the two-divided sensor 506 and the reference signal of the function generator 504, and the distance control circuit 510 is used so that the amplitude becomes constant. Performs feedback distance control. At this time, the z-direction feedback distance control signal is simultaneously input to the computer 517 as a shape signal of the surface of the sample 508.

Further, the laser light from the laser A 512 is incident on the optical fiber 511 connected to the near-field optical probe 501 by the condenser lens A 513, and
Near-field light is generated from a minute aperture provided at the tip.
The near-field light is scattered on the surface of the sample 508, and the scattered light 514 is condensed by the condensing lens B515.
Detect at 16. The near-field optical signal output from the photomultiplier tube 516 is input to the computer 517.

The computer 517 outputs a scanning signal in the xy direction of the xyz stage 507, and outputs the signal in accordance with the position of the tip of the near-field optical probe 501 with respect to the surface of the sample 508.
The magnitude of the near-field light signal and the shape signal is displayed on the display 51.
By mapping on 8, a near-field optical microscope image and a shear force (atomic force) microscope image can be obtained simultaneously.

By using the near-field optical probe joined in a V-shape as described above, the amount of shake of the near-field optical probe in the y-direction during the x-direction oscillation of the near-field optical probe for shear force detection can be reduced to a negligibly small amount, The resolution of the near-field optical microscope image and the shear force microscope image has been improved. Note that the near-field light probe described here can be used for a microfabrication device or a recording / reproducing device using near-field light other than the microscope, and has the same effect.

FIG. 6 is a diagram showing a configuration of a near-field optical probe using a probe by bending a tip portion having a probe at a predetermined angle with respect to a root portion. FIG. 6A is a cross-sectional view as viewed from above, and FIG. 6B is a cross-sectional view as viewed from the side. In FIG. 6, reference numeral 601 denotes a thinned optical fiber A having a cylindrical rod shape having a diameter of 20 μm, and reference numeral 602 denotes a thinned optical fiber B also having a cylindrical rod shape having a diameter of 20 μm. At a position of 100 μm from the tip of the thinned optical fiber A601, the thinned optical fiber A601 is bent at an angle of θ1 = 75 °. This situation is shown in FIG.

The tip of the bent thinned optical fiber A601 is sharpened to a conical shape with a radius of curvature of 1 μm or less,
The probe 603 is configured. Thinned optical fiber A601
Is coated with a 150 nm-thick Al coating 604 as a metal coating for shielding. At the tip of the probe 603, a minute opening 605 having a diameter of 100 nm or less is provided.

From the tip of the thinned optical fiber A601, 15
One end of the thinned optical fiber B 602 is bonded to the position of 0 μm with an adhesive B 606 to form a bonded portion 607. The root portion of the thinned optical fiber A601 is fixed to the optical probe support substrate 608 with an adhesive A609. The other end of the thinned optical fiber B 602 on the side opposite to the joint 607 is fixed to the optical probe support substrate 608 with an adhesive C610.

With the above configuration, the thinned optical fiber A6
By causing an elastic deformation in the z direction shown in the figure at 01, the probe 603 at the tip can be displaced in the z direction. However, since the thinned optical fiber B602 is joined in a V-shape, the amount of elastic deformation in the x direction is reduced, and the amount of displacement of the probe 603 in the x direction can be reduced.

As a specific numerical example, the diameter is 20 in each case.
The material of the thinned optical fiber A 601 and the thinned optical fiber B 602 is quartz, and the optical probe support substrate 60
Assuming that the lengths of the thinned optical fiber A 601 and the thinned optical fiber B 602 protruding from FIG. 8 are 3 mm and the angle between the thinned optical fiber A 601 and the thinned optical fiber B 602 is 45 °, the near-field optical probe When a force is applied to the tip, the elastic constant for the displacement of the tip in the x direction is 0.1 N / m, while the elastic constant for the displacement in the y direction is 3500 N / m, which is 35,000 times harder.
For this reason, it can be seen that when the same force is applied, the displacement of the probe 603 in the x direction is extremely smaller than the displacement in the z direction.

The root portion of the thinned optical fiber A601 is as follows:
The light is connected to the original optical fiber 611 before being thinned, and evanescent light can be generated from the minute aperture 605 by making light 612 incident from the end of the original optical fiber 611. In addition, it is possible to detect the intensity of the near-field light by emitting the propagating light obtained by converting the near-field light detected by the minute aperture 605 in the thinned optical fiber A601 from the end of the original optical fiber 611. Become.

Next, a method for manufacturing a near-field optical probe having a bent tip according to the present embodiment will be described with reference to FIGS. FIG. 7 is a diagram illustrating a process of bending the tip of the thinned optical fiber by irradiating a CO ₂ laser beam. In this embodiment, the optical fiber 701 thinned by chemical etching in the same manner as described with reference to FIG.
= 45 ° thinned optical fiber support member 702
Fixed to. The beam spot diameter is set to 5 using a condenser lens 703 at a position of 140 (= 100 × √2) μm from the tip.
The CO ₂ laser light 704 focused to 0 μm is applied. As a result, the laser beam irradiation position 705 of the thinned optical fiber 701 melts, and the tip of the probe 706 tends to bend in the z direction in the drawing due to surface tension.

At this time, the xyz stage 70
By attaching a bending stopper 708 forming an angle of θ3 = 30 ° with respect to the horizontal plane on the horizontal axis 7 and arranging the tip of the bending stopper 708 in the middle of the bending path of the probe 706, the bending of the probe 706 is bent. 70
8 bound. After this, the CO ₂ laser light 704
By stopping the irradiation, the tip of the thinned optical fiber 701 can be bent at an angle of 75 ° (= 45 ° + 30 °). Here, by adjusting the angles of the thinned light supporting member 702 and the bending stopper 708, it is possible to perform bending at a desired angle.

Here, the advantage of performing the processing while irradiating the CO ₂ laser with the thinned optical fiber obliquely (45 ° in this embodiment) will be described. FIG. 8 is a diagram illustrating an example in which a thinned optical fiber is horizontally supported during CO ₂ laser irradiation.

In FIG. 8, with respect to the thinned optical fiber 801 supported horizontally, the C is positioned slightly before the tip.
When the O ₂ laser beam 802 is irradiated, the laser beam irradiation position 8
05 melts and bends upward in the figure. As a result, the probe tip 803 sharpened in the chemical etching in the previous process.
Enters the irradiation range of the CO ₂ laser beam, and the sharpened tip melts to form a probe 804 with a rounded tip. As a result, the diameter of an opening formed in an opening forming step to be described later becomes large, and the resolution as a near-field optical probe is reduced.

On the other hand, as shown in FIG. 7, if the center axis of the thinned optical fiber 701 is supported obliquely at an angle shifted from the vertical with respect to the CO ₂ laser beam irradiation direction, (when there is no bending stopper) However, it is possible to prevent the sharpened tip from being rounded without turning the tip into the CO ₂ laser irradiation range even after bending about 75 °. Also, C
The advantage of performing processing using a bending stopper when irradiating O ₂ laser will be described. FIG. 9 is a diagram showing an example in which there is no bending stopper during CO ₂ laser irradiation.

Referring to FIG. 9, a thinned optical fiber 902 supported obliquely by using a thinned optical fiber support member 901.
The CO ₂ laser beam 9 slightly before the tip.
03, the laser beam irradiation position 904 is melted,
Bend upward in the figure. Thereafter, the laser irradiation is stopped to stop the bend. However, since the bend speed increases sharply as the bend angle increases, it is difficult to control the bend angle to a desired angle. As a result, FIG. As shown in B and C, it is easy to obtain a probe in which the bending angle of the tip greatly differs. On the other hand, if a bending stopper is used as shown in FIG. 7, a probe having a desired bending angle can be manufactured with high yield.

Next, as shown in FIG. 10, the thinned optical fiber 1001 whose tip is bent is attached to the thinning optical fiber support member 1007 at the time of rotation coating which is inclined at an angle of θ4 = 15 ° with respect to the rotary stage 1006. To support. At this time, the bent distal end of the thinned optical fiber 1001 is arranged in the direction normal to the rotating stage surface. The rotation stage 1006 has a center axis 1003 in the direction normal to the stage surface.
And rotate. In this state, Al deposition 10 is performed from the lateral direction.
02 is performed to form a light-shielding Al film 1005 having a thickness of 150 nm. The distal end of the thinned optical fiber 1001 is a spherical surface having a radius of curvature of 1 μm or less. On the other hand, when metal deposition is performed from the lateral direction, the thickness of the distal end becomes smaller than that of the side surface. 1004 is formed. At this time, the size of the opening is substantially the same as the radius of curvature of the tip.

Here, if the rotation is performed with the rotation axis at the time of rotating metal deposition being coincident with the center axis of the bent portion of the tip of the thinned optical fiber, in the case of a near-field optical probe having a varied bending angle, The direction of the minute aperture can be made to coincide with the direction of the central axis of the bent portion at the tip of the thinned optical fiber. However, as shown in FIG. 11, different near-field optical probes C1101 and D110
2, the directions of the minute openings C1103 and D1104 do not match the normal directions of the surface to be processed, the surface of the sample, and the surface 1105 of the recording medium, and are directed in different directions.
The distribution direction of the generated near-field light is different, and a displacement occurs during processing, observation, recording and reproduction.

On the other hand, as shown in FIG. 12, the angle θ4 at which the thinned optical fiber 1001 having a bent end is fixed to the rotary stage 1006 is set to an angle θ4 as shown in FIG. At the time of attachment, the angle of inclination of the central axis 1206 of the near-field optical probe with respect to the surface to be processed, the surface of the sample, or the surface 1201 of the recording medium can be matched. That is, by this, the bending stopper is not used at the time of bending by CO ₂ laser irradiation, and FIG.
As shown in FIG. 10, a thin metal optical fiber whose bending angle is varied as shown in FIG. 10 is also subjected to rotary metal vapor deposition as shown in FIG. 10 to form an opening, thereby forming a fine aperture at the tip of the manufactured near-field optical probes A1202 and B1203. A1204, B
Although the direction of 1205 is different from the bending direction of the tip of the thinned optical fiber, it can always match the normal direction of the surface to be processed, the surface of the sample, or the surface of the recording medium.

As described above, the thinned optical probe 1303 having the fine end formed by bending the tip is coated with the resin 1302 so as to cover the fine opening 1301 as shown in FIG. . With this resin coating, it is possible to prevent the minute opening from being closed during the second-stage Al deposition. A method for performing resin coating will be described with reference to FIG. The thinned optical probe 1401 with the tip bent and a minute aperture formed is connected to the z-stage 140
2 on the support 1403. z stage 1402
Is driven in the downward direction in FIG.
The small opening 1405 at the tip is infiltrated with the resin solution 1404. Thereafter, the z-stage 1402 is driven upward in FIG.
01 By pulling up the tip, resin coating is performed on the tip.

Here, as the resin solution, a resin that can be removed later by a solvent, for example, an acrylic resin or a resist can be used. Here, since the thinned optical fiber 1401 has a small elastic constant with respect to the bending in the z direction in the figure, the minute opening 1 is caused by the surface tension of the resin solution 1404.
Not only the 405 part but also the root infiltrates. Therefore, a sinking stopper 1406 shown in FIG. 14 is attached, and a portion of the thinned light 1401 near the bent portion at the tip is supported so as to be supported from below. Thereby, the minute aperture 1405 at the tip of the thinned optical fiber 1401
Only a portion can be selectively resin-coated.

Next, as shown in FIG.
Thinned optical fiber 15 coated with resin 1502
Al deposition 1504 is performed from the lateral direction while rotating around the central axis 1506 with respect to the side surface of
A light shielding Al film 1505 is formed. Thereafter, the resin coat is removed by ultrasonic cleaning in a solvent. By performing Al vapor deposition while rotating in two stages in the order described above, generation of unnecessary leak light from the boundary between the resin coated portion and the coated portion can be avoided.

In the subsequent steps, as described above, an optical fiber of a sufficient length is fusion-spliced to the end of the thinned optical fiber opposite to the probe, and a near-field optical probe is passed through this optical fiber. Takes light in and out when used. Further, using the apparatus shown in FIG. 4, a thinned optical fiber A manufactured as described above and another thinned optical fiber B similarly thinned using chemical etching are combined into a V-shape. Then, a V-shaped cantilever-shaped near-field optical probe shown in FIG. 6 is manufactured.

FIG. 16 shows the configuration of a contact AFM distance control type near-field optical probe scanning and processing apparatus using a V-shaped cantilever type near-field optical probe by bending a tip portion manufactured by the above process and using a probe. . FIG.
6, the V attached to the probe support substrate 1602
A laser is emitted from the laser B1603 to the vicinity of the tip of the near-field optical probe 1601 in the shape of a cantilever from behind, and the position change of the reflected light beam spot is detected by the two-part sensor 16.
Detect at 04. The difference signal of the two-divided sensor 1604 is an AFM signal corresponding to the amount of deflection of the tip of the near-field optical probe 1601 in the z direction, and is input to the computer 1608.

On the other hand, by driving the xyz stage 1605 in the z direction, the tip of the near-field optical probe 1601 is moved below 10E-7 [N] with respect to the surface of the resist 1606 on the substrate 1607 mounted on the xyz stage 1605. Make contact so that van der Waals force works. In this state, an xyz stage drive signal is output from the computer 1608, and the xyz stage 1605 is moved two times in the xy direction.
Dimensionally scan.

The computer 1608 maps the magnitude of the AFM signal to the xy-direction drive signal of the xyz stage 1605, so that the resist 160
6 can be known, and based on this, the resist 1
606, that is, positioning of the tip of the near-field optical probe 1601 with respect to the substrate 1607 is performed. Further, the laser light from the laser A 1610 is incident on the optical fiber 1609 connected to the near-field light probe 1601 by the condenser lens A 1611, and the near-field light is generated from a minute aperture provided at the tip of the near-field light probe 1601.

When the tip of the near-field light probe 1601 is brought into contact with the surface of the resist 1606 so that a van der Waals force of 10E-7 [N] or less acts between them, the distance between them is 100 nm or less. Resist 1606
The intensity of the near-field light on the surface is sufficiently large. X of xyz stage 1605 output from computer 1608
resist 1606 based on the y drive signal and the AFM signal
When the tip of the near-field optical probe is positioned at a predetermined position with respect to the substrate 1607, the laser A 161 is output based on the laser control signal output from the computer 1608.
Light irradiation / non-irradiation control of 0 is performed, and exposure, that is, formation of a latent image pattern 1612 on the resist 1606 is performed. Subsequent processes are the same as those in a normal semiconductor process.

By using the above-described V-shaped cantilever type near-field optical probe, the amount of deflection in the y-direction of the near-field optical probe during scanning in the y-direction during exposure can be reduced to a negligibly small value. The processing accuracy of the field light fine processing equipment has been improved. The near-field optical probe described in this embodiment can be used for a microscope or a recording / reproducing apparatus using near-field light in addition to the fine processing apparatus, and has the same effect.

In the present embodiment, the case where the contact AFM control system is used as the distance control system of the near-field optical probe with respect to the resist (sample, recording medium) surface has been described. By changing the value of the elastic constant in the bending direction by changing the probe diameter or length, a tapping AFM control method or a non-contact AFM control method can be used.

[0052]

As described above, according to the present invention, in a method of manufacturing a cantilever type near-field optical probe for melting and bending a processing beam irradiation portion, a near-field By irradiating the processing beam at an angle shifted from the vertical, the rounding of the tip due to melting can be avoided, and a near-field optical probe with high resolution is realized.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a near-field optical probe according to an embodiment of the present invention.

FIG. 2 is an explanatory view of a step of thinning an optical fiber by using chemical etching in an embodiment of the present invention.

FIG. 3 is an explanatory view of a step of forming a light-shielding metal film from a lateral direction while rotating a thinned optical fiber in an embodiment of the present invention.

FIG. 4 is a diagram illustrating a thinned optical fiber according to an embodiment of the present invention;
Explanatory drawing of the process of joining in a character shape.

FIG. 5 is a configuration diagram of a shear force distance control type near-field optical microscope using a V-shaped near-field optical probe in an embodiment of the present invention.

FIG. 6 is a configuration diagram of a near-field optical probe manufactured by using the process of the present invention in the embodiment of the present invention.

FIG. 7 is an explanatory view of a step of bending the tip of a thinned optical fiber by irradiating a CO ₂ laser beam in the embodiment of the present invention.

FIG. 8 is a diagram illustrating an example in which a thinned optical fiber is horizontally supported during irradiation of a CO ₂ laser in an embodiment of the present invention.

FIG. 9 is a view showing an example in which a bending stopper is not provided during irradiation of a CO ₂ laser in the embodiment of the present invention.

FIG. 10 is an explanatory view of a step of forming a light-shielding metal film from the lateral direction while rotating a thinned optical fiber having a bent end, which is a first film forming step in the embodiment of the present invention.

FIG. 11 is a diagram showing a state in which the direction of a minute opening at the tip of a near-field optical probe in the embodiment of the present invention is different from the normal direction of the surface to be processed, the sample surface, or the recording medium surface.

FIG. 12 is a diagram showing a state in which the direction of a minute opening at the tip of the near-field optical probe in the embodiment of the present invention matches the normal direction of the surface to be processed, the surface of the sample, or the surface of the recording medium.

FIG. 13 is a configuration diagram of a minute opening at the tip of a thinned optical fiber covered with a resin coat according to an embodiment of the present invention.

FIG. 14 is an explanatory diagram of a resin coating step in the example of the present invention.

FIG. 15 is an explanatory view of a step of forming a light-shielding metal film from a lateral direction on a side surface of a thinned optical fiber whose end is covered with a resin coat, which is a second film forming step in the embodiment of the present invention.

FIG. 16 is a configuration diagram of a contact AFM distance control type near-field optical probe scanning and processing apparatus using a V-shaped cantilever type near-field optical probe in an embodiment of the present invention.

FIG. 17 is an explanatory diagram of an example in which the tip of an optical probe performs a movement deviated from reciprocating vibration in a shear force distance control in a conventional example.

FIG. 18 is an explanatory diagram of a conventional example in which the tip of an optical probe receives a frictional force and bends in a direction opposite to a scanning direction.

[Explanation of symbols]

101: thinned optical fiber A 102: thinned optical fiber B 103: probe 104: Al coating for light shielding 105: minute opening 106: adhesive B 107: bonding portion 108: optical probe support substrate 109: adhesive A 110: Adhesive C 111: Original optical fiber 112: Light 201: Teflon container 202: Etching solution 203: Optical fiber 204: Cladding 205: Core 206: Core exposed portion 207: Optical fiber at the end of etching 208: Sharpened portion 209: Optical fiber 301 during etching 301: thinned optical fiber 302: Al vapor deposition 303: central axis 304: optical aperture 305: light shielding Al film 401: thinned optical fiber A 402: thinned optical fiber B 403: probe support substrate 404 : Adhesive A 405: xyzθ drive stage 406: Loop 407: Adhesive B 408: Adhesive C 501: V-shaped near-field optical probe 502: Probe support substrate 503: Piezo element 504: Function generator 505: Laser B 506: Two-part sensor 507: xyz stage 508: Sample 509: Lock-in amplifier 510: Distance control circuit 511: Optical fiber 512: Laser A 513: Condensing lens A 514: Scattered light 515: Condensing lens B 516: Photomultiplier tube 517: Computer 518: Display 601: Fine line Optical fiber A 602: Thinned optical fiber B 603: Probe 604: Al coating for light shielding 605: Micro aperture 606: Adhesive B 607: Bonded portion 608: Optical probe support substrate 609: Adhesive A 610: Adhesive C 611 : Original optical fiber 612: Light 701: Fine Kahikari Fiber 702: thin line Kahikari fiber support member 703: condenser lens 704: CO ₂ laser beam 705: laser light irradiation position 706: probe 707: xyz stage 708: Curved Stopper 801: horizontally supported thinned light Fiber 802: CO ₂ laser beam 803: Probe sharpened by chemical etching 804: Probe with rounded tip 805: Laser beam irradiation position 901: Thin optical fiber support member 902: Thin optical fiber 903: CO ₂ Laser light 904: Laser light irradiation position 1001: Thinned optical fiber bent at the tip 1002: Al vapor deposition 1003: Central axis 1004: Optical aperture 1005: Al film for light shielding 1006: Rotating stage 1007: Thinned light during rotary coating Fiber support member 1101: Near-field optical probe C 110 : Near-field optical probe D 1103: minute aperture C 1104: minute aperture D 1105: surface to be processed, sample surface, recording medium surface 1201: surface to be processed, sample surface, recording medium surface 1202: near-field optical probe A 1203: proximity Field light probe B 1204: minute aperture A 1205: minute aperture B 1206: central axis of near-field optical probe 1301: minute aperture 1302: resin coating 1303: thin end optical fiber with bent end and small opening 1401: bent end , Thinned optical fiber 1402: z-stage 1403: support base 1404: resin solution 1405: small opening 1406: sinking stopper 1501: small opening forming portion 1502: resin coating 1503: thinned optical fiber 1504: Al vapor deposition 1505: Al film for shielding light 1506: Central axis 1601: V-shaped cantilever type near-field optical probe 1602: Probe support substrate 1603: Laser B 1604: Two-part sensor 1605: Xyz stage 1606: Resist 1607: Substrate 1608: Computer 1609: Optical fiber 1610: Laser A 1611: Light collecting Lens A 1612: Latent image pattern 1701: Sample surface 1702: Optical probe 1703: Piezo element

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Claims (12)

[Claims] 1. An irradiation part is melted by irradiation of a laser beam,
A method for producing a near-field optical probe for producing a near-field optical probe by bending a tip portion having a probe at a predetermined angle with respect to a root portion, wherein the near-field optical probe has an irradiation direction of the laser light. A method for producing a near-field optical probe, wherein the laser beam is irradiated at an angle shifted from the vertical direction. 2. The method for manufacturing a near-field optical probe according to claim 1, wherein in the bending, a bending stopper is arranged to limit a bending angle of the near-field optical probe. 3. An apparatus for manufacturing a near-field optical probe, comprising: bending means for bending a tip portion having a probe with respect to a root portion at a predetermined angle by melting a portion irradiated by laser light. Means for supporting the near-field light probe at an angle shifted from a vertical direction which is the irradiation direction of the laser light, and the near-field light probe supported by the support means irradiates the near-field light probe with the laser light. An apparatus for producing a near-field optical probe, which is configured to receive irradiation of the laser light from an angle shifted from a direction. 4. The near-field according to claim 3, wherein the bending means has a bending stopper, and the bending stopper limits a bending angle of the near-field optical probe. Optical probe manufacturing equipment. 5. A method for producing a near-field optical probe according to any one of claims 1 to 2, and a method for producing a near-field optical probe according to any one of claims 3 to 4. Forming a light-shielding material on the tip portion and the root portion bent by the bending process using a near-field optical probe, wherein a first film-forming process on the tip portion and a second film-forming process on the root portion are performed. Divided into two stages,
A near-field optical probe, wherein a film is formed with a light-shielding material on a probe surface in a direction perpendicular to the rotation axis while rotating the probe around different axes during film formation in each of these film formation steps. Method of manufacturing. 6. The method according to claim 1, wherein in the first film forming step, an angle for supporting a root portion of the near-field optical probe with respect to a direction perpendicular to the rotation axis is attached to an apparatus using the near-field optical probe. 6. The method for producing a near-field optical probe according to claim 5, wherein an angle formed by a root portion of the near-field optical probe with respect to a sample surface facing the tip of the near-field optical probe. 7. A method for producing a near-field optical probe according to any one of claims 1 to 2, or a device for producing a near-field optical probe according to any one of claims 3 to 4, or Item 7. A near-field optical probe produced by the method for producing a near-field optical probe according to any one of Items 5 to 6. 8. The near-field optical probe according to claim 7, wherein the near-field optical probe is supported on a substrate such that the tip of the near-field optical probe is a free end of a cantilever, while one end is supported by the substrate. The other end of the rod-shaped member different from the near-field light probe is joined to the vicinity of the tip of the near-field light probe so that a V-shape is formed by the near-field light probe and the rod-shaped member. And a near-field optical probe. 9. A step of using the near-field optical probe according to claim 7 and supporting the near-field optical probe on a substrate such that the tip of the near-field optical probe is a free end of a cantilever; When joining one end of another rod-shaped member to the vicinity of the tip of the near-field optical probe, joining the rod-shaped member to the near-field optical probe so that the angle formed by the rod-shaped member becomes a predetermined angle; and And a step of supporting the other end of the rod-shaped member. 10. A near-field optical probe for observing a sample surface with a near-field optical probe, wherein the near-field optical probe is the near-field optical probe according to any one of claims 7 to 8, or the ninth aspect. A near-field optical microscope comprising a near-field optical probe manufactured by the above-described method for manufacturing a near-field optical probe. 11. A near-field light fine processing apparatus for finely processing a surface to be processed by a near-field light probe, wherein the near-field light probe is the near-field light probe according to any one of claims 7 to 8, or A near-field light microfabrication apparatus comprising a near-field light probe manufactured by the method for manufacturing a near-field light probe according to claim 9. 12. A near-field optical probe according to claim 7, wherein said near-field optical probe is a near-field optical recording / reproducing apparatus for recording / reproducing information by using a near-field optical probe. Item 10. A near-field optical recording / reproducing apparatus comprising a near-field optical probe manufactured by the near-field optical probe manufacturing method according to Item 9.