JP3651800B2 - Pinhole manufacturing method and manufacturing apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a manufacturing method and a manufacturing apparatus of pinholes passed through the metal film, and more particularly to a manufacturing method and a manufacturing apparatus of a pinhole composed of nanometer size.
[0002]
[Prior art]
In recent years, nano-optical devices having nanometer-sized microstructures such as single-molecule optical memories and single-electronic devices are being put to practical use on the basis of the development of microfabrication technology. A near-field optical microscope having high resolution has attracted attention as a technology indispensable for the development or evaluation of the above-described elements. This near-field optical microscope can know the physical properties, for example, by detecting the light intensity, wavelength, polarization, etc. of light emitted from or transmitted through the sample.
[0003]
The near-field optical microscope has a sharpened portion formed by sharpening the core at one end of an optical fiber in which a cladding is provided around the core, and the sharpened portion is covered with a metal such as Au or Ag. An optical image having a resolution exceeding the wavelength of light can be obtained. That is, by using such a near-field optical microscope, in addition to measuring the physical properties of the sample with high resolution, it is possible to perform memory operations such as writing and reading, as well as optical processing.
[0004]
Incidentally, when the physical properties of a sample are measured by the near-field optical microscope, the shape of the sample is measured by detecting evanescent light localized in a region smaller than the wavelength of light on the sample surface. Then, the evanescent light generated by irradiating the sample with light under the total reflection condition is scattered by the above-described probe and converted into propagating light. The converted propagation light is guided to the core of the optical fiber through the sharpened portion where the probe is formed, and is detected by the detector connected to the other emission end of the optical fiber. That is, this near-field optical microscope can perform both scattering and detection by a probe (see, for example, Patent Document 1) provided at a sharp point.
[0005]
[Patent Document 1]
JP-A-10-082792 [0006]
[Problems to be solved by the invention]
By the way, as a probe array or a lens array of such a near-field optical microscope, a pinhole made of a highly permeable oxidized region is indispensable. There is a problem that the physical properties of the sample cannot be measured with high resolution, and the operation and processing of the nano-optical device cannot be realized with high accuracy.
[0007]
The present invention has been devised in view of the above-described problems, and an object of the present invention is to provide a pinhole manufacturing method and manufacturing apparatus having a nanometer size.
[0008]
[Means for Solving the Problems]
In order to solve the above-described problems, the pinhole manufacturing method according to the present invention has a metal layer formed on the surface excluding the tip of the core from which one end of an optical fiber provided with a cladding around the core is projected. The protruding portion of the optical probe having a protruding portion is disposed in the vicinity of the metal film of the substrate on which the metal film is deposited, and light is irradiated from the protruding portion of the optical probe to the metal film of the substrate . Depending on the light, a gas existing in the vicinity of the metal film is activated, or electrons in the metal film are emitted to oxidize the metal film to produce a pinhole.
[0009]
In this pinhole manufacturing method, oxygen emitted from the optical probe is modified into ozone by the light emitted from the optical probe, or light with a wavelength exceeding the work function is directly irradiated onto the metal film. By releasing electrons existing inside the metal film, the oxidation of the metal film is promoted.
[0010]
In addition, the pinhole manufacturing apparatus according to the present invention includes an optical probe having a protruding portion in which a metal layer is formed on the surface excluding a tip portion of a core protruding from one end of an optical fiber provided with a cladding around the core. The protrusion of the optical probe is disposed in the vicinity of the metal film of the substrate on which the metal film is deposited, and the metal film of the substrate is irradiated with light from the protrusion of the optical probe, and the metal film It is characterized in that pinholes are produced by oxidizing.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0013]
FIG. 1 shows an optical probe 1 for realizing a method for producing a pinhole according to the present invention and a metal film 2 for producing a pinhole.
[0014]
The optical probe 1 is used in, for example, a near-field optical microscope that identifies physical properties based on light emission or transmitted light obtained from a sample, and includes an optical waveguide 11 and a protrusion 12 as shown in FIG.
[0015]
The optical waveguide unit 11 includes an optical fiber in which a clad 21 is provided around the core 20. The core 20 and the clad 21 are each made of SiO ₂ glass, and the structure is controlled so that the refractive index of the clad 21 is lower than that of the core 20 by adding F, GeO ₂ , B ₂ O ₃ or the like. .
[0016]
The protruding portion 12 is configured by sharpening the core 20 a protruding from the clad at one end of the optical waveguide portion 11. The projecting core 20a is configured as a conical shape that gradually tapers up to the tip 13 as shown in FIG. Incidentally, the projecting portion 12 is formed so that the root diameter is shorter than the diameter of the core 20. Further, a metal layer 31 is formed on the surface excluding the tip portion 13 of the projected core 20a.
[0017]
Incidentally, such a protruding portion 12 of the optical probe 1 is produced by subjecting the optical waveguide portion 11 to selective chemical etching. In this selective chemical etching, the core 20 is selectively sharpened by immersing the fiber in a buffered hydrofluoric acid solution made of, for example, NH ₄ F, HF, or H ₂ O for about 1 hour and removing the end of the cladding 21. In the present invention, the dissolution rate may be controlled by the composition of the etching solution and the material constituting the optical fiber, and the tip of the core 20 may be sharpened to, for example, a tip curvature radius of 10 nm. Finally, the sharpened core 20 is finished by coating a metal layer 31 such as Au on the side surface excluding the tip 13.
[0018]
The metal film 2 is made of a conductive metal such as Zn or Al, and is deposited on the substrate 3 in advance. The substrate 3 is made of Al ₂ O ₃ , CaF _{2, a} glass material, or the like, and is obtained by cutting out a large crystal having a diameter of 3 to 4 inches grown by a pulling method into a wafer shape. In order to uniformly deposit the above-described metal film 2 on the cut-out substrate 3, the surface of the substrate 3 is usually subjected to processing such as mechanical polishing, chamfering, and cleaning.
[0019]
In the optical probe 1 and the metal film 2 having the above-described configuration, when ultraviolet light is emitted from the optical probe 1, oxygen in the air in the vicinity of the tip portion 13 can be reformed into ozone as expressed by the equation (1).
O ₂ + O = O ₃ (1)
The ozone thus modified has higher activity than oxygen and can promote the oxidation of the metal film 2. Therefore, by arranging the optical probe 1 so that the tip portion 13 is in the vicinity of the location where the pinhole is to be produced, the metal film 2 at that location can be oxidized as shown in FIG. Here, since the tip end portion 13 can be sharpened to a tip curvature radius of about 10 nm, the metal film 2 to be oxidized can be controlled to a region having a radius of about 10 nm at the minimum.
[0020]
In addition, in the metal film 2 where the oxidation is promoted by ozone, an oxidation region 31 having a high permeability is gradually formed. For example, when Zn is used as the metal film 2, highly transparent ZnO can be formed. Finally, nanometer-sized pinholes 32 are formed as shown in FIG. 2 (b).
[0021]
That is, in the present invention, the nanometer-sized pinhole 32 can be formed at a desired position by controlling the arrangement of the optical probe 1 and the tip curvature radius.
[0022]
Further, in the present invention, not only the case where the oxidation of the metal film 2 is promoted by modifying oxygen present in the atmosphere to ozone, but the optical probe 1 is installed in an oxygen atmosphere in advance (1 The oxidation represented by the formula can be further promoted.
[0023]
Further, when light having a wavelength exceeding the work function is directly irradiated onto the metal film 2 by the optical probe 1 having the above-described configuration, electrons existing inside the metal film 2 can be emitted, and the metal film 2 It can also oxidize itself.
[0024]
As described above, in the pinhole manufacturing method to which the present invention is applied, the vicinity of the substrate 3 on which the metal film 2 is deposited from the optical probe 1 having the projecting part projecting one end of the optical fiber provided with the clad around the core. The metal film 2 is oxidized by activating the gas existing in the vicinity of the substrate 3 or emitting electrons in the metal film 2 in response to the irradiated light, thereby causing a nanometer-sized pinhole. 32 can be produced.
[0025]
Further, by emitting light while gradually moving the optical probe 1 at nanometer intervals, a large number of pinholes 32 can be produced at nanometer intervals as shown in FIG. The large number of pinholes 32 thus produced can be applied as a probe array or a lens array, and these can be applied to, for example, a near-field optical microscope. As a result, the near-field optical microscope using nanometer-sized pinholes can measure the physical properties of the sample with nanometer-level resolution, and furthermore, the operation and processing of nano-optical devices can be realized with high accuracy. .
[0026]
In the pinhole manufacturing method to which the present invention is applied, by applying a voltage by bringing the metal film 2 and the probe 4 close to each other, water vapor existing between them is electrolyzed to oxidize the metal film 2. Also good. FIG. 4 shows the probe 4 for realizing the pinhole manufacturing method according to the present invention and the metal film 2 for manufacturing the pinhole.
[0027]
The probe 4 is a conductive metal probe having a tip sharpened to a size of 100 nm or less, like a probe used in an atomic force microscope, for example.
[0028]
When a voltage is applied between the metal film 2 and the probe 4 by the power source 5, moisture present between the two is electrolyzed. And the hydroxide ion produced | generated by this electrolysis reacts with the metal film 2, The metal film 2 of the said location can be oxidized. For example, when Zn is used as the metal film 2, highly transparent ZnO can be formed, and finally a nanometer-sized pinhole 32 as shown in FIG. 2B is formed. be able to.
[0029]
That is, in the present invention, the nanometer-sized pinhole 32 can be formed at a desired position by applying an electric field and controlling the arrangement of the probe 4 and the tip curvature radius. As a substitute for the probe 4, it is needless to say that the electrolysis as described above may be realized by using a probe whose surface is coated with metal.
[0030]
Thus, in the pinhole manufacturing method to which the present invention is applied, a voltage is applied between the metal film 2 deposited on the substrate 3 and the probe 4 having conductivity, and a probe is generated according to the applied voltage. Water vapor in the vicinity of the needle 4 is electrolyzed. As a result, the metal film 2 can be oxidized, and as a result, a nanometer-sized pinhole 32 can be produced.
[0031]
【The invention's effect】
As described in detail above, the pinhole manufacturing method to which the present invention is applied is a method of reforming oxygen present in the atmosphere to ozone by light emitted from an optical probe, or exceeding a work function to a metal film. Light of a wavelength is directly irradiated to emit electrons existing in the metal film. Thereby, a metal film can be oxidized and a nanometer-sized pinhole can be produced.
[0032]
As described in detail above, the pinhole manufacturing method to which the present invention is applied applies voltage between the metal film and the conductive probe, and electrolyzes the water present between the two. Thereby, it is made to react with the hydroxide ion produced by electrolysis, a metal film is oxidized, and a nanometer-sized pinhole can be produced.
[Brief description of the drawings]
FIG. 1 is a view showing an optical probe for realizing a method for producing a pinhole according to the present invention and a metal film for producing a pinhole.
FIG. 2 is a diagram illustrating an example in which a pinhole is formed by oxidizing a metal film.
FIG. 3 is a diagram showing an example in which a large number of nanometer-sized pinholes are produced by oxidizing a metal film.
FIG. 4 is a diagram showing an example in which water vapor existing between the metal film 2 and the probe 4 is electrolyzed by applying a voltage by bringing the metal film 2 and the probe 4 close to each other.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Optical probe, 2 Metal film, 3 Substrate, 4 Probe, 5 Power supply, 11 Optical waveguide part, 12 Protrusion part, 20 Core, 21 Cladding, 31 Metal layer, 32 Pinhole

Claims (6)

An optical probe having a protruding portion in which a metal layer is formed on the surface excluding the tip of the core protruding from one end of an optical fiber provided with a cladding around the core. Arranged in the vicinity of the metal film, irradiating the metal film of the substrate from the protruding portion of the optical probe ,
According to the irradiated light, a gas existing in the vicinity of the metal film is activated, or electrons in the metal film are emitted to oxidize the metal film to produce a pinhole. How to make a pinhole. From the protruding portion made of a nanometer size of the optical probe, a method for manufacturing a pinhole according to claim 1, wherein the irradiating light to the metal film deposited on the substrate. 3. The method for manufacturing a pinhole according to claim 1, wherein the metal film deposited on the substrate is irradiated with ultraviolet light from the protrusion of the optical probe. From the optical probe the protruding portions, according to claim 1, 2 or 3 the method for manufacturing a pin hole, wherein the irradiating light to the configured the metal film of Zn or Al was deposited on the substrate. 2. The method for producing a pinhole according to claim 1, wherein light is irradiated from the protrusion on the optical probe to a metal film deposited on the substrate placed in an oxygen atmosphere. An optical probe having a protruding portion in which a metal layer is formed on the surface excluding the tip of the core protruding one end of an optical fiber provided with a cladding around the core;
  The projecting portion of the optical probe is disposed in the vicinity of the metal film on the substrate on which the metal film is deposited, and the metal film on the substrate is irradiated with light from the projecting portion of the optical probe to oxidize the metal film. An apparatus for producing a pinhole, characterized by producing a pinhole.

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