JP3871208B2 - Planar probe, method for manufacturing the same, and optical pickup device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a planar probe, a method for manufacturing the same, and an optical pickup device.
[0002]
[Prior art]
For example, by irradiating an optical recording medium typified by CD (Compact Disc) or DVD (Digital Versatile Disc) with laser light, data was recorded on the optical recording medium or recorded on the optical recording medium. A data recording / reproducing method for reproducing data is known.
[0003]
In recent years, the recording density of optical recording media has been increasing, so that, for example, in order to record / reproduce ultra-high-density recorded data using the above-described recording / reproducing method, the wavelength of light used is reduced. In addition, by increasing the NA of the lens used, etc., the spot size of the light irradiated on the recording surface of the optical recording medium is miniaturized.
[0004]
However, the spot size of the laser light irradiated on the recording surface of the optical recording medium is as large as the wavelength of the laser light due to the diffraction limit of the light only by shortening the wavelength of the laser light or increasing the NA of the lens used. Can only be obtained. For this reason, inconveniences such as the fact that recording bits cannot be miniaturized at the time of ultra-high density recording and that crosstalk occurs at the time of reproduction of data recorded at an ultra-high density will occur.
[0005]
As one of the solutions to the limit of recording and reproduction due to the diffraction limit of light, an optical system using “near-field light” has been proposed. That is, when light is incident from one of two media having different refractive indexes under the total reflection condition, light propagating through one medium is totally reflected at the boundary surface with the other medium. A region (near field) in which only a non-propagating electric field component exudes over a part of the boundary surface is formed. The region where only the non-propagating electric field component oozes out is called “near field”. Such a region can be formed by an optical fiber having an aperture finer than the wavelength of light to be introduced, such as an optical fiber probe of a near-field light microscope. The near field due to such a small opening has a lateral extent that is almost the same as the opening dimension, and the intensity decreases exponentially as the distance from the opening increases, and does not exude as much as or more than the opening.
[0006]
When a minute scatterer is inserted in such a near-field region, the near-field is scattered and converted as near-field light of propagating light. Since the near-field light generated in the near field does not bleed out to the same extent or more as the aperture, the use of such near-field light can provide a resolution that exceeds the diffraction limit of light, and can be used for an optical recording medium. It can be expected that the optical recording medium on which ultra-high density recording or ultra-high density recording has been performed will be satisfactorily performed.
[0007]
However, although the resolution exceeding the diffraction limit of light can be obtained by using near-field light, near-field light has a very weak intensity compared to general propagation light. For this reason, for example, a method for effectively generating and detecting near-field light is being sought, for example, by arranging a probe having a very thin tip in proximity to an optical recording medium such as an optical disk.
[0008]
In recent years, as with high-density recording, speeding up of recording and reproduction has been studied. As one of them, a planar probe having an array configuration having a plurality of openings in a grid pattern has been proposed. By using such a planar probe, (target recording / reproducing scanning speed) / (numerical aperture) can be set as the scanning speed, so even if the actual scanning speed is low, the target It is possible to increase the scanning speed of recording / reproducing.
[0009]
As such a planar probe, for example, as disclosed in Japanese Patent Laid-Open No. 2001-208672, a projection having an opening at the tip by performing anisotropic etching using the silicon crystal surface of the SOI substrate, In some cases, a bank portion standing around the protrusion is formed on one side of the SOI substrate. Further, for example, as disclosed in Japanese Patent Laid-Open No. 2000-182264, a conical projection pattern formed of a photosensitive resin is provided on one surface side of a plate-like probe material using an electron beam. There is a technique in which a conical protrusion is formed on one side of a probe material by dry etching the protrusion pattern and transferring it to the probe material.
[0010]
The near-field light generated from such a planar probe is also arranged in the vicinity of the optical recording medium because the intensity is much weaker than general propagating light as described above.
[0011]
[Problems to be solved by the invention]
However, such a flat probe has a large variation in aperture size. That is, as described above, the near-field light can propagate only as much as the aperture size (cannot ooze out), and the intensity decreases exponentially. For this reason, if the apertures forming the flat probe vary widely, the intensity of the near-field light to the optical recording medium with a certain distance from the flat probe differs greatly, and there is a problem in that recording / reproduction cannot be performed. is there.
[0012]
An object of the present invention is to make it possible to generate highly efficient near-field light when using such weak near-field light.
[0013]
[Means for Solving the Problems]
The planar probe according to the first aspect of the present invention includes a light-transmitting substrate, a light-transmitting columnar structure portion formed on the substrate, and the columnar structure portion formed on the columnar structure portion. And a conical structure portion that forms a protrusion, and a filling material that is made of a material having a lower refractive index than the material of the columnar structure portion and is embedded around the columnar structure portion on the substrate.
[0014]
Therefore, by embedding an embedding material having a refractive index lower than that of the columnar structure portion around the columnar structure portion forming a part of the protrusion, the structure is equivalent to the core and clad of the optical fiber. By making the light incident on the base of the part totally reflected by the columnar structure part, it can be introduced into the conical structure part with low loss, and near-field light can be generated with high efficiency from the tip of the conical structure part. Become. In addition, the height of the columnar structure portion is not required to be strict, so that a margin at the time of manufacture can be increased, and the removal process can be omitted without the need to remove the embedded material.
[0015]
According to a second aspect of the present invention, in the planar probe according to the first aspect, the embedding material is made of a material that is transparent to a light wavelength to be used and absorbs at least a part of visible light.
[0016]
Therefore, for example, by coloring the embedding material so as to be transparent with respect to the used wavelength light, the probe position, that is, the position of the protrusion can be easily identified, and the optical axis can be easily aligned at the time of light introduction. .
[0017]
According to a third aspect of the present invention, in the planar probe according to the first or second aspect, the columnar structure portion is formed in a columnar shape, and the cone-shaped structure portion is formed in a conical shape or a truncated cone shape.
[0018]
Therefore, it is possible to generate near-field light with higher efficiency.
[0019]
According to a fourth aspect of the present invention, in the planar probe according to any one of the first to third aspects, the substrate, the columnar structure portion, and the conical structure portion are integrally formed of the same material.
[0020]
Therefore, it is possible to obtain the material easily and inexpensively without requiring any special processing for the initial material.
[0021]
According to a fifth aspect of the present invention, in the planar probe according to the fourth aspect, the same material is quartz or optical glass.
[0022]
Therefore, by forming the substrate and the protrusions with quartz or optical glass, the material is easily available and inexpensive, and also has a high refractive index and transmittance, and generates a high-efficiency near-field light. A probe can be provided.
[0023]
A sixth aspect of the present invention is the planar probe according to any one of the first to third aspects, wherein the columnar structure portion and the conical structure portion are made of the same material and are made of a material different from the substrate. Has been.
[0024]
Therefore, for example, a material that is difficult to form into a plate by itself, or a material whose strength and handleability are reduced by thinning it even though it needs to be thin because of low transmittance. Can be used for the substrate, increasing the choice of substrate material.
[0025]
According to a seventh aspect of the present invention, in the planar probe according to any one of the first to third aspects, the substrate is backed by a translucent support material provided on the back side thereof.
[0026]
Therefore, for example, a material that is difficult to form into a plate by itself, or a material whose strength and handleability are reduced by thinning it even though it needs to be thin because of low transmittance. Can be used for the substrate, and the selectivity of the refractive index, the transmittance, and the wavelength used is increased.
[0027]
According to an eighth aspect of the present invention, in the planar probe according to any one of the first to seventh aspects, a protective wall is formed around the protrusion on the surface side of the substrate by the same material as the protrusion.
[0028]
Therefore, the mechanical damage can be prevented by protecting the protrusions with the protective wall against the impact applied from the surroundings.
[0029]
A ninth aspect of the present invention is the planar probe according to any one of the first to eighth aspects, further comprising a light shielding film that covers at least a slope portion of the conical structure portion.
[0030]
Therefore, for example, when recording / reproducing with respect to an optical recording medium using a flat probe, it is possible to prevent the near-field light from being generated from a portion other than the tip of the protrusion by the light shielding film, thereby improving the light use efficiency. Can do.
[0031]
The invention according to claim 10 is the planar probe according to any one of claims 1 to 9, wherein the planar probe is formed on the back side of the substrate or the support material, and the light incident from the back side is incident on the columnar structure portion. A light condensing function part for condensing light at the root part is provided.
[0032]
Therefore, for example, when performing recording / reproduction with respect to an optical recording medium using a planar probe, the planar probe of the present invention including a condensing function unit that condenses light incident from the back side on the base of the protrusion is used. This eliminates the need for a separate condenser lens.
[0033]
According to an eleventh aspect of the present invention, in the planar probe according to any one of the first to tenth aspects, a plurality of the protrusions are arranged in an array on the surface side of the substrate.
[0034]
Therefore, for example, when recording / reproducing is performed on an optical recording medium using a planar probe, it is effective to increase the speed.
[0035]
The method for manufacturing a planar probe according to claim 12 includes a step of forming a columnar structure portion made of a translucent material on a substrate having translucency, and the columnar structure around the columnar structure portion on the substrate. A step of embedding an embedding material made of a material having a lower refractive index than that of the material of the columnar structure portion and having a higher etching rate than that of the material of the columnar structure portion; And etching the portion and the filling material by isotropic etching to form a conical structure portion on the columnar structure portion.
[0036]
Accordingly, it is not necessary to strictly control the height of the columnar structure portion, a margin at the time of manufacturing can be increased, and a step of removing the embedding material is not required. For example, the invention according to claims 1 to 11 Thus, it is possible to provide an effective manufacturing method for forming a planar probe as described above.
[0037]
An optical pickup device according to a thirteenth aspect of the present invention is arranged such that a light source that emits light to irradiate an optical recording medium and a tip of a protrusion are positioned on the optical recording medium side. The planar probe according to any one of 11 and a condensing unit that condenses the light emitted from the light source at the base of the protrusion.
[0038]
Therefore, since the planar probe according to any one of claims 1 to 9 or 11 is provided, when the planar probe is used for recording / reproducing with respect to the optical recording medium, highly efficient near-field light can be generated, The recording / reproducing operation can be performed satisfactorily.
[0039]
An optical pickup device according to a fourteenth aspect of the present invention is a light source that emits light to irradiate an optical recording medium, and a tip of a protrusion that is disposed on the optical recording medium side, and is emitted from the light source. The planar probe according to claim 10, wherein light is condensed on a base portion of the protrusion by a condensing function unit.
[0040]
Therefore, in addition to the effects and advantages of the thirteenth aspect of the invention, for example, when recording / reproducing is performed on an optical recording medium using a flat probe, the light incident from the back side is condensed on the base of the protrusion. By providing the planar probe according to claim 10 provided with a condensing function part, it is not necessary to use a condensing lens separately, and the optical axis alignment between the light source and the condensing function part is sufficient, and the assemblability is improved. To do.
[0041]
DETAILED DESCRIPTION OF THE INVENTION
A first embodiment of the present invention will be described with reference to FIGS. The present embodiment shows an application example to an optical pickup device provided with a planar probe. FIG. 1 is a schematic side view showing an optical pickup device portion in a recording / reproducing apparatus that performs recording or reproduction with respect to an optical recording medium D using a flat probe 1.
[0042]
First, the planar probe 1 is configured to have a tapered protrusion 3 protruding from the surface side of a light-transmitting substrate 2. The protrusion 3 is constituted by a columnar columnar structure portion 4 formed on the substrate 2 and a truncated cone-shaped cone-shaped structure portion 5 formed on the columnar structure portion 4 and constituting the main body of the probe. . Further, an embedding material 6 embedded on the periphery of the columnar structure portion 4 on the substrate 2 is provided. A material whose refractive index is lower than that of the columnar structure portion 4 is used. In the present embodiment, a plurality of, for example, two protrusions 3 are formed on the substrate 2 in an array form. Further, the slope portion of the conical structure portion 5 and the surface of the filling material 6 are covered with a light shielding film 7 described later.
[0043]
The optical pickup device according to the present embodiment includes a semiconductor probe 11 as a light source that emits laser light, a laser emitted from the semiconductor laser 11, together with the planar probe 1 that is closely disposed with the protrusion 3 side as the optical recording medium D side. A collimating lens 12 that collimates the light, a beam splitter 13 that deflects the collimated laser beam toward the projection 3 side of the planar probe 1, and the deflected laser beam from the back side of the substrate of the planar probe 1. The objective lens 14 is provided as a condensing means for condensing light at the base of the protrusion 3 (columnar structure 4), and is condensed from the objective lens 14 onto the root of the protrusion 3 (columnar structure 4). The near-field light 15 having a spot diameter equal to or less than the diffraction limit of the light can be emitted from the tip side of the conical structure portion 5 by passing the laser beam through the columnar structure portion 4 and the conical structure portion 5. Accordingly, the recording pattern 16 is recorded on an optical recording medium D which closely facing the tip of the cone-shaped structure 5. A light receiving optical system 17 is provided on the return light side of the beam splitter 13. The optical recording medium D is driven to rotate by a spindle motor or the like (not shown).
[0044]
In such a configuration, when the laser beam is emitted from the semiconductor laser 11, the laser beam incident in the focused state from the substrate 2 side to the root portion of the columnar structure portion 4 through the objective lens 14 is projected. 3 is reflected on the boundary surface with air (the flat surface 5a at the tip of the conical structure 5). At this time, a part of the laser light incident on the protrusion 3 crosses the boundary surface (the flat surface 5a at the tip of the conical structure 5), and only the non-propagating electric field component oozes out from the boundary surface to the optical recording medium D side. A region (near field) is formed. Due to the characteristics of the near-field light 15, the near-field light 15 has a lateral extent only about the same as the size of the plane 5 a serving as an opening. The dimension of the flat surface 5a serving as the opening is set to be smaller than the wavelength of the laser beam to be used, and the distance between the protrusion 3 and the optical recording medium D is set to be approximately the same as the diameter of the flat surface 5a of the protrusion 3. Therefore, the recording surface of the optical recording medium D can be irradiated with the near-field light 15 that is a non-propagating electric field component that has oozed out into the near-field. Thereby, it is possible to obtain a resolution exceeding the diffraction limit of light.
[0045]
In such an operation, the planar probe 1 according to the present embodiment has an embedding material 6 having a low refractive index around the columnar structure portion 4 having a high refractive index, as shown in FIG. , That is, a structure equivalent to a core and a clad in an optical fiber, and light incident on the base of the columnar structure portion 4 is totally reflected by the columnar structure portion 4 and has a very low loss and a cone shape. Introduced into the structure 5. As a result, near-field light 15 having a spot diameter with high efficiency and less than the diffraction limit of light is emitted from the tip of the cone-shaped structure 5, and the recording pattern 16 is recorded on the optical recording medium D installed near the tip of the cone-shaped structure 5. Can be formed.
[0046]
Next, a method for manufacturing such a planar probe 1 will be described with reference to FIGS. First, as shown in FIG. 3A, the columnar structure portion 4 is formed on the substrate 2. A known technique may be used to form the columnar structure portion 4. Specifically, there are the following methods.
(1) By machining such as a milling machine or electric discharge machining.
{Circle around (2)} A columnar resist pattern is formed on the substrate, and anisotropic etching is performed using this resist pattern as a mask.
(3) A sacrificial layer is formed on the substrate, a through hole is formed in the sacrificial layer by a normal photolithography-etching process, a columnar material is embedded in the through hole by a method such as CVD or sputtering, and the sacrificial layer is removed. .
[0047]
Next, as shown in FIG. 3B or FIG. 3C, the periphery of the columnar structure portion 4 is embedded with an embedding material 6. The height of the embedding material 6 may be the same as that of the columnar structure portion 4 as shown in FIG. 3B, or may be a height that covers the columnar structure portion 4 as shown in FIG. . The embedding material 6 can be etched with the same etching solution or etching gas as the material of the columnar structure portion 4 in addition to a material having a lower refractive index than the material of the columnar structure portion 4 and etched from the material of the columnar structure portion 4. Use fast rate materials.
[0048]
As a specific embedding material, an optical resin is suitable. Various optical resins are commercially available, and have an advantage that the selection range of the etching rate and the refractive index is wide. It is also possible to use a material that is liquid and becomes glass by firing (for example, OCD manufactured by Tokyo Ohka Kogyo Co., Ltd.). This material has an advantage that the etching rate and the refractive index can be controlled by the firing conditions. These materials can be formed by a method such as dipping or spin coating. Further, as the filling material, various materials formed by a method such as CVD or sputtering can be used.
[0049]
Next, as shown in FIG. 3D, etching is performed by isotropic etching. At this time, since the etching rate of the material of the embedding material 6 is faster than that of the material of the columnar structure portion 4, the columnar structure portion 4 is left as the etching progresses. Specifically, as shown in an enlarged view in FIG. 4, the material of the columnar structure portion 4 is the vertical direction V. ₁ , Horizontal direction H ₁ As the burying material 6 disappears by etching, the shape of the conical structure portion 5 is taken. In FIG. 3 (d) and FIG. 4, dH ₁ Indicates the etching amount of the filling material 6.
[0050]
The angle (vertical angle) of the conical structure portion 5 is determined by the ratio between the etching rate of the material of the filling material 6 and the etching rate of the material of the columnar structure portion 4. That is, the larger the value of (the etching rate of the material of the burying material 6 / the etching rate of the material of the columnar structure 4), the more the cone-shaped structure 5 having a sharp tip.
[0051]
When the etching is finished when the conical structure portion 5 has a suitable value, the tip-shaped planar probe 1 as shown in FIG. 3E or FIG. 3F is obtained. The shape of the conical structure portion 5 at this time is defined by the ratio between the etching rate of the filling material 6 and the etching rate of the columnar structure portion 4 and the etching time. If the etching is completed when the etching amount of the material of the columnar structure portion 4 is equal to or less than the radius, as shown in FIG. 3E, a truncated cone-shaped cone-shaped structure portion 5 having a flat surface 5a at the tip is obtained. . In order to obtain a conical shape as shown in FIG. 3 (f), the etching amount of the material of the columnar structure portion 4 may be set to be equal to or larger than the radius. In addition, if the etching is continued even after the etching amount of the material of the columnar structure portion 4 becomes equal to or larger than the column radius, the cone-shaped structure portion 5 having a sharper tip is obtained.
[0052]
When the planar probe 1 is manufactured by the manufacturing method of the present embodiment, the thickness of the base portion of the protrusion 3 can be controlled by the size (diameter) of the columnar structure portion 4, and the etching rate of the material of the burying material 6 can be controlled. The angle (vertical angle) of the conical structure 5 can be controlled by the ratio of the etching rate of the material of the columnar structure 4 and the shape of the protrusion 3 can be controlled.
[0053]
Further, the material of the substrate 2, the columnar structure portion 4 and the conical structure portion 5 at this time is the same material, specifically, quartz or optical glass in terms of availability, ease of processing, and light transmittance. Is suitable.
[0054]
Incidentally, when not using the structure / manufacturing method of the present embodiment, it is necessary to have a structure as shown in FIG. When the planar probe 101 having no columnar structure as shown in FIG. 11A is formed, the etching time is determined by the thickness of the embedding material (= the height of the columnar structure), and the embedding material The ratio of the etching rate of the columnar structure material and the etching rate of the columnar structure material is determined by the material used and the etching conditions, so that the thickness of the embedded material (= the height of the columnar structure) is adjusted to the target cone-shaped structure portion 102. Must be strictly controlled. Further, when the planar probe 103 having the structure as shown in FIG. 11B is formed, a step of removing the filling material is required after the target cone-shaped structure portion 104 is completed.
[0055]
By using the structure / manufacturing method of the present embodiment, there is an advantage that the height of the columnar structure portion 4 does not need to be strictly controlled as compared with the structure / manufacturing method of FIG. In other words, there is an advantage that a margin at the time of manufacturing can be increased. Further, as compared with the structure of FIG. 11B, there is an advantage that the step of removing the filling material can be omitted and the number of manufacturing steps is smaller.
[0056]
As a specific example, a photosensitive resin pattern having a diameter of 2 μm and a height of 2 m is formed on a quartz substrate 2 for a cylindrical columnar structure, and subsequently, C ₄ F ₈ ECR etching using a gas was performed to obtain a columnar structure 4 having a base of 2 μm and a height of 3 μm as shown in FIG.
[0057]
The substrate 2 was spin-coated with OCD (manufactured by Tokyo Ohka Kogyo Co., Ltd.) and baked to obtain an embedded material 6 in an embedded state as shown in FIG. Then, the structure of the flat probe 1 as shown in FIG. 3E or FIG. 3F was obtained by etching with hydrofluoric acid. The shape of FIG. 3E or FIG. 3F is controlled by the etching time.
[0058]
At this time, by adding cobalt ions to the OCD, the embedding material 6 is colored (absorbs part of visible light wavelength). If the wavelength of 730 nm is used for the recording and reading light used in the optical pickup device, the embedding material 6 can be colored without absorbing the recording and reading light, and the probe position (position of the conical structure portion 5) can be easily discriminated. Thus, it is possible to form the planar probe 1 that can easily align the optical axis when introducing light.
[0059]
By the way, as shown in FIG. 1, the planar probe 1 of the present embodiment is a portion excluding the flat surface 5 a at the tip of the conical structure portion 5 on the surface side of the substrate 2, that is, a slope portion of the conical structure portion 5. The planar probe 1 is configured such that the surface of the embedding material 6 is covered with a light shielding film 7 made of a metal film such as Al. More specifically, after the surface of the flat probe 1 formed as described above is formed with 2000 Ａｌ of Al film by sputtering, the Al film at the tip of the protrusion 3 is removed by FIB, whereby the plane with the light-shielding film 7 is provided. The mold probe 1 is obtained.
[0060]
According to such a planar probe 1, when the recording / reproducing is performed on the optical recording medium using the optical pickup device, the light shielding film 7 indicates that near-field light is generated from a portion other than the tip of the conical structure portion 5. Can be prevented.
[0061]
A second embodiment of the present invention will be described with reference to FIG. The same parts as those shown in the first embodiment are denoted by the same reference numerals, and description thereof is also omitted (the same applies to the following embodiments).
[0062]
In the present embodiment, the photosensitive resin pattern for the protective wall is formed at the same time as the photosensitive resin pattern for the columnar columnar structure portion, so that a protrusion is formed around the protrusion 3 on the surface side of the substrate 2 as shown in FIG. The protective wall 8 for preventing damage 3 is also formed at the same time.
[0063]
The protective wall 8 is also integrally formed of the same material as the substrate 2 and the protrusion 3, and the height from the substrate surface is also the same height as the protrusion 3. By making the height of the protective wall 8 the same as that of the protrusion 3, the protective wall 8 becomes an obstacle when the flat probe 1 is applied to an optical pickup device and used for recording / reproducing with respect to the optical recording medium D. The tip of the protrusion 3 can be brought close to the optical recording medium.
[0064]
Here, the planar shape of the protective wall 8 can take any appropriate shape, and can be an annular shape, a square frame shape, a triangular frame shape, an elliptical shape, or the like surrounding the protrusion 3. However, when applied to the optical pickup device as in the present embodiment, as shown in FIG. 6, the planar shape is substantially U-shaped, and the protrusion 3 is formed except for a part of the opening 8a. The flat probe 1 is arranged so as to continuously surround the periphery, and the position and direction of the planar probe 1 are positioned so that the opening 8a is positioned downstream with respect to the rotation direction of the optical recording medium D that is rotationally driven. Is preferred. According to this, when recording / reproducing in the recording / reproducing apparatus, an air flow is generated around the protrusion by the rotation of the optical recording medium D. Since the flat probe 1 is arranged so that the opening 8a of the protective wall 8 is positioned downstream of the protrusion 3 with respect to the airflow generated by the rotation of the optical recording medium D, the protrusion 3 and the protective wall 8 are arranged. It is possible to remove foreign matter between the protective wall 8 and the projection 3 by using the air flow, and to suppress the accumulation of foreign matter between the protective wall 8 and the protrusion 3.
[0065]
Furthermore, as shown in FIG. 7, the planar shape is a shape that continuously surrounds the periphery of the protrusion 3 except for some openings 8a, and is symmetrical with the opening 8a with the protrusion 3 in between. It is preferable to have a shape in which a cusp portion 8b that cusps toward the direction away from the protrusion 3 is provided at a certain position. Here, it is preferable to position the arrangement position / direction of the flat probe 1 so that the apex portion 8b is positioned upstream with respect to the rotation direction of the optical recording medium D that is rotationally driven. According to this, the air flow generated by the rotation of the optical recording medium is diverted in the left-right direction by the apex portion 8b at the position of the protective wall 8, and therefore, by using this air flow, foreign matter is surrounded around the protective wall 8. It is possible to prevent the foreign matter from being deposited on the inner peripheral side and the outer peripheral side of the protective wall 8.
[0066]
A third embodiment of the present invention will be described with reference to FIG. In the present embodiment, in configuring the flat probe 1, a material that cannot be molded into a substrate as a probe material or difficult to mold, or has low transmittance due to requirements such as a refractive index, a transmittance, and a wavelength used, This is in consideration of a case where it is necessary to use a material that needs to be thinly used as a substrate. For this reason, the planar probe 1 according to the present embodiment is configured to include a translucent support material as the backing material 22 on the back side of the substrate 21.
[0067]
For example, the Si wafer 21 was anodically bonded to the glass substrate 22, the Si wafer 21 was polished, and formed to a thickness of Si 5 μm. Thereafter, a photosensitive resin pattern for the columnar columnar structure portion having the same shape was formed on the Si wafer 21 under the same conditions as in the specific example described above. Then SF ₆ ECR etching using a gas was performed to cover the entire surface of the Si wafer 21 (2 μm) of the probe material on the glass substrate 22, and the Si columnar structure portion 4 having a base of 2 μm and a height of 3 μm was obtained thereon. The substrate 21 was spin-coated with OCD (manufactured by Tokyo Ohka Kogyo Co., Ltd.) and baked to obtain an embedded state of the embedded material 6. Thereafter, the planar probe 1 as shown in FIG. 8 is obtained by etching with hydrofluoric acid in the same manner as in the specific example described above.
[0068]
As a material for forming the backing material 22, for example, a light-transmitting material such as quartz can be used in addition to the glass described above.
[0069]
As a material for forming the substrate 21, that is, the protrusion 3, for example, in addition to the above-mentioned Si, diamond, Si ₃ N ₄ Etc. can be used. Diamond, Si ₃ N ₄ , Si, etc. are formed on the surface of the backing material 22 by sputtering or CVD (Chemical Vapor Deposition) to form a diamond film, Si ₃ N ₄ Used as a film or Si film.
[0070]
Other materials for forming the substrate 21, that is, the protrusion 3, include single crystal Si, SiO. ₂ , Ge, glass, crystal quartz, C (diamond), amorphous Si, microcrystal (microcrystal) Si, polycrystalline Si, Si _x N _y (x and y are optional), TiO ₂ , ZnO, TeO ₂ , Al ₂ O ₃ , Y ₂ O ₃ , La ₂ O ₂ S, LiGaO ₂ , BaTiO ₃ , SrTiO ₃ , PbTiO ₃ , KNbO ₃ , K (Ta, Nb) O ₃ (KTN), LiNbO ₃ LiTaO ₃ , Pb (Mg _1/3 Nb _2/3 ) O ₃ , (Pb, La) (Zr, Ti) O ₂ , (Pb, La) (Hf, Ti) O ₃ , PbGeO ₃ , Li ₂ GeO ₃ , MgAl ₂ O ₄ CoFe ₂ O ₄ , (Sr, Ba) Nb ₂ O ₆ , La ₂ Ti ₂ O ₇ , Nd ₂ Ti ₂ O ₇ , Ba ₂ TiSi ₁₂ O ₈ , Pb ₅ Ge ₃ O ₁₁ , Bi ₄ Ge ₃ O ₁₂ , Bi ₄ Si ₃ O ₁₂ , Y ₃ Al ₅ O ₁₂ , Gd ₃ Fe ₅ O ₁₂ , (Gd, Bi) ₃ Fe ₅ O ₁₂ , Ba ₂ NaNbO ₁₅ , Bi ₁₂ GeO ₂ O, Bi ₁₂ SiO ₂ , Ca ₁₂ Al ₁₄ O ₃₃ , LiF, NaF, KF, RbF, CsF, NaCl, KCl, RbCl, CsCl, AgCl, TlCl, CuCl, LiBr, NaBr, KBr, CsBr, AgBr, TlBr, LiI, NaI, KI, CsI, Tl (Br, I ), Tl (Cl, Br), MgF ₂ , CaF ₂ , SrF ₂ , BaF ₂ , PbF ₂ , Hg ₂ CI ₂ , FeF ₃ , CsPbCl ₃ , BaMgF ₄ , BaZnF ₄ , Na ₂ SbF ₅ LiClO ₄ ・ 3H ₂ O, CdHg (SCN) ₄ , ZnS, ZnSe, ZnTe, CdS, CdSe, CdTe, α-HgS, PbS, PbSe, EuS, EuSe, GaSe, LiInS ₂ , AgGaS ₂ , AgGaSe ₂ TiInS ₂ TiInSe ₂ , TlGaSe ₂ , TlGaS ₂ , As ₂ S ₃ , As ₂ Se ₃ , Ag ₃ AsS ₃ , Ag ₃ SbS ₃ , CdGa ₂ S ₄ , CdCr ₂ S ₄ , TlTa ₃ S ₄ , Tl ₃ TaSe ₄ , Tl ₃ VS ₄ , Tl ₃ AsS ₄ , Tl ₃ PSe ₄ , GaP, GaAs, GaN, (Ga, Al) As, Ga (As, P), (InGa) P, (InGa) As, (Ga, AI) Sb, Ga (AsSb), (lnGa) (AsP), (GaAI) (AsSb), ZnGeP ₂ , CaCO ₃ , NaNO ₃ , Α-HIO ₃ , Α-LiIO _Three , KIO ₂ F ₂ , FeBO ₃ , Fe ₃ BO ₆ , KB ₅ O ₈ ・ 4H ₂ O, BeSO ₄ ・ 2H ₂ O, CuSO ₄ ・ 5H ₂ O, Li ₂ SO ₄ ・ H ₂ O, KH ₂ PO ₄ , KD ₂ PO ₄ , NH ₄ H ₂ PO ₄ , KH ₂ AsO ₄ , KD ₂ AsO ₄ CSH ₂ AsO ₄ , CsD ₂ AsO ₄ , KTiOPO ₄ , RbTiOPO ₄ , (K, Rb) TiOPO ₄ , PbMoO ₄ , Β-Gd ₂ (MoO ₄ ) ₃ , Β-Tb ₂ (MoO ₄ ) ₃ , Pb ₂ MoO ₅ , Bi ₂ WO ₆ , K ₂ MoOS ₂ ・ KCl, YVO ₄ Ca ₃ (VO ₄ ) ₂ , Pb ₅ (GeO ₄ ) (VO ₄ ) ₂ , CO (NH ₂ ) ₂ , Li (COOH) · H ₂ O, Sr (COOH) ₂ , (NH ₄ CH ₂ COOH) ₃ H ₂ SO ₄ , (ND ₄ CD ₂ COOD) ₃ D ₂ SO ₄ , (NH ₄ CH ₂ COOH) ₃ H ₂ BeF, (NH ₄ ) ₂ C ₂ O ₄ ・ H ₂ O, C ₄ H ₃ N ₃ O ₄ , C ₄ H ₉ NO ₃ , C ₆ H ₄ (NO ₂ ), C ₆ H ₄ NO ₂ Br, C ₆ H ₄ NO ₂ CI, C ₆ H ₄ NO ₂ NH ₂ , C ₆ H ₄ (NH ₄ ) OH, C ₆ H _Four (CO ₂ ) ₂ HCs, C ₆ H ₄ (CO ₂ ) ₂ HRb, C ₆ H ₃ NO ₂ CH ₃ NH ₂ , C ₆ H ₃ CH ₃ (NH ₂ ) ₂ , C ₆ H ₁₂ O ₅ ・ H ₂ OKH (C ₈ H ₄ O ₄ ), ClOH ₁₁ N ₃ O ₆ , [CH ₂ ・ CF ₂ ] n or the like can be used.
[0071]
A fourth embodiment of the present invention will be described with reference to FIG. In the present embodiment, with respect to the flat probe 1, the columnar structure portion 4 and the conical structure portion 5 are made of the same material but different from the substrate 2.
[0072]
As a specific example, for example, quartz is prepared as the substrate 2, and an aluminum film 3 μm is formed as a sacrificial layer on the quartz by a sputtering method, and the sacrificial layer is penetrated with a diameter of 2 μm by a normal photolithography-etching process. A hole is formed, and then Si is buried in the through-hole as a material of the columnar structure portion 4 by CVD, and aluminum is removed by etching to obtain a columnar structure portion 4 made of Si having a base of 2 μm and a height of 3 μm on quartz. It was. OCD (manufactured by Tokyo Ohka Kogyo Co., Ltd.) was spin-coated and fired on this Si to obtain an embedded state of the embedded material 6. Thereafter, the planar probe 1 as shown in FIG. 9 is obtained by etching with hydrofluoric acid in the same manner as in the specific example described above.
[0073]
Therefore, for example, a material that is difficult to form into a plate by itself, or a material whose strength and handleability are reduced by thinning it even though it needs to be thin because of low transmittance. Can be used for the substrate, increasing the choice of substrate material.
[0074]
Also in the present embodiment, as the material for the columnar structure portion 4 and the conical structure portion 5, various materials as described above as the substrate 21 material in the third embodiment can be used.
[0075]
A fifth embodiment of the present invention will be described with reference to FIG. In the planar probe 1 according to the present embodiment, light incident on the back surface side of the substrate 2 (or the backing material 22) from the back surface side in correspondence with the position of the protrusion 3 is the root of the protrusion 3 (columnar structure portion 4). The convex lens shape part 31 as a condensing function part condensed on a part is integrally formed.
[0076]
According to the planar probe 1 of the present embodiment, the objective lens 14 can be dispensed with when configuring the optical pickup device. Further, in the configuration example as shown in FIG. 1, it is necessary to align the three optical axes of the light source 11, the objective lens 14, and the planar probe 1, whereas according to the structure of the present embodiment, the light source 11- Convex lens-shaped part 31 (= planar probe 1) is advantageous in that it is sufficient to align the optical axes at two locations, and the assembly is facilitated.
[0077]
As a specific manufacturing method, a planar probe having a basic structure was obtained by the same method as the specific example described above. Next, after forming a circular photosensitive resin pattern at a position corresponding to the protrusion 3 on the back side of the substrate 2, the photosensitive resin is softened and aggregated by baking at 160 ° C. for 1 hour to form a convex lens-shaped photosensitive resin pattern. Formed. Subsequently, C on the back surface of the substrate 2 ₄ F ₈ ECR etching using a gas (the etching ratio between the photosensitive resin and the quartz substrate is approximately 1: 2) is performed until the resin pattern is completely removed, whereby the convex lens-shaped portion 21 is integrally formed. A mold probe 1 was obtained.
[0078]
【The invention's effect】
According to the planar probe of the first aspect of the present invention, an embedding material having a refractive index lower than that of the columnar structure portion is embedded around the columnar structure portion that forms a part of the protrusion, so that the core of the optical fiber It has the same structure as the clad, and light incident on the base of the columnar structure can be totally reflected by the columnar structure, so that it can be introduced into the cone structure with low loss, closer to the tip of the cone It is possible to generate the field light with high efficiency, and the height of the columnar structure is not required to be strict, and a margin at the time of manufacturing can be increased, and there is no need to remove the embedded material. The removal process can also be omitted.
[0079]
According to the second aspect of the present invention, in the planar probe according to the first aspect, the probe position, that is, the position of the protrusion is determined by, for example, coloring the embedding material so as to be transparent to the used wavelength light. It can be easily discriminated, and optical axis alignment at the time of light introduction can be easily performed.
[0080]
According to a third aspect of the present invention, in the planar probe according to the first or second aspect, the columnar structure portion is formed in a columnar shape, and the conical structure portion is formed in a conical shape or a truncated cone shape. Therefore, it is possible to generate near-field light with higher efficiency.
[0081]
According to the invention described in claim 4, in the planar probe according to any one of claims 1 to 3, the substrate, the columnar structure portion, and the conical structure portion are integrally formed of the same material. The material does not require special processing, and the material can be easily and inexpensively obtained.
[0082]
According to the invention described in claim 5, in the planar probe according to claim 4, by forming the substrate and the protrusion with quartz or optical glass, the material is easily obtained at low cost, and has an excellent refractive index, It is possible to provide a planar probe that has transmittance and generates high-efficiency near-field light.
[0083]
According to a sixth aspect of the present invention, in the planar probe according to any one of the first to third aspects, the columnar structure portion and the conical structure portion are made of the same material and different from the substrate. Therefore, for example, it is difficult to form a plate by itself, or it may be necessary to reduce the thickness because the transmittance is low. New materials can be used for the substrate and the choice of substrate material can be increased.
[0084]
According to the invention described in claim 7, in the planar probe according to any one of claims 1 to 3, the substrate is backed by a translucent support material provided on the back side thereof. For example, a substrate made of a material that is difficult to be formed into a plate by itself or a material whose strength and handleability are reduced by thinning although it needs to be thin because of low transmittance. And the selectivity of the refractive index, transmittance, and wavelength used can be increased.
[0085]
According to the invention described in claim 8, in the planar probe according to any one of claims 1 to 7, the substrate includes a protective wall formed around the protrusion by the same material as the protrusion on the surface side of the substrate. By protecting the protrusion with a protective wall against an impact applied from the surroundings, the mechanical breakage can be prevented.
[0086]
According to the ninth aspect of the present invention, in the planar probe according to any one of the first to eighth aspects, since the light shielding film that covers at least the slope portion of the front structure portion is provided, for example, the planar probe is used. Thus, when recording / reproducing with respect to the optical recording medium, it is possible to prevent the near-field light from being generated from a portion other than the tip of the protrusion by the light shielding film, and the light use efficiency can be improved.
[0087]
According to a tenth aspect of the present invention, in the planar probe according to any one of the first to ninth aspects, for example, when recording / reproducing is performed on an optical recording medium using the planar probe, the light is incident from the back side. By using the planar probe of the present invention that includes a condensing function unit that condenses light at the base of the protrusion, it is not necessary to separately use a condensing lens.
[0088]
According to the eleventh aspect of the present invention, in the planar probe according to any one of the first to tenth aspects, a plurality of protrusions are arranged in an array on the surface side of the substrate. This is effective for speeding up recording / reproducing with respect to an optical recording medium using a mold probe.
[0089]
According to the planar probe manufacturing method of the twelfth aspect of the present invention, it is not necessary to strictly control the height of the columnar structure, the manufacturing margin can be increased, and the embedded material is removed. No manufacturing process is required, and for example, it is possible to provide a manufacturing method effective for forming a planar probe as in the inventions of claims 1 to 11.
[0090]
According to the optical pickup device of the thirteenth aspect of the present invention, since the flat probe according to any one of the first to ninth or eleventh aspects is provided, when the flat probe is used for recording / reproducing with respect to the optical recording medium, Efficient near-field light can be generated and recording / reproducing operation can be performed satisfactorily.
[0091]
According to the optical pickup device of the fourteenth aspect of the invention, in addition to the effect of the thirteenth aspect of the invention, for example, when recording / reproducing is performed on the optical recording medium using a flat probe, the light is incident from the back side. It is not necessary to use a condensing lens separately by providing the flat type probe according to claim 10 provided with a condensing function part which condenses light at the base part of a projection, and between a light source and a condensing function part The alignment of the optical axes is sufficient, and the assemblability can be improved.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of an optical pickup device showing a first embodiment of the present invention.
FIG. 2 is an enlarged cross-sectional view showing the protruding portion.
FIG. 3 is a schematic cross-sectional view showing a method of manufacturing a planar probe in the order of steps.
FIG. 4 is an enlarged cross-sectional view showing a part of the process in the middle of the process.
FIG. 5 is a schematic cross-sectional view showing a planar probe according to a second embodiment of the present invention.
FIG. 6 is a schematic plan view showing an example of the protective wall.
FIG. 7 is a schematic plan view showing another example of the protective wall.
FIG. 8 is a schematic sectional view showing a planar probe according to a third embodiment of the present invention.
FIG. 9 is a schematic sectional view showing a planar probe according to a fourth embodiment of the present invention.
FIG. 10 is a schematic sectional view showing a planar probe according to a fifth embodiment of the present invention.
FIG. 11 is a schematic cross-sectional view showing a planar probe showing a proportionality.
[Explanation of symbols]
1 Planar probe
2 Substrate
3 Protrusions
4 Columnar structure
5 Conical structure
6 Embedding material
7 Shading film
8 Protective wall
11 Light source
14 Condensing means
21 Substrate
22 Support material
31 Condensing function unit

Claims (14)

A substrate having translucency;
A translucent columnar structure formed on the substrate;
A conical structure part formed on the columnar structure part to form a protrusion together with the columnar structure part;
An embedding material made of a material having a lower refractive index than the material of the columnar structure portion and embedded around the columnar structure portion on the substrate;
A planar probe comprising: The planar probe according to claim 1, wherein the embedding material is made of a material that is transparent to a light wavelength to be used and absorbs at least a part of visible light. The planar probe according to claim 1 or 2, wherein the columnar structure portion is formed in a columnar shape, and the cone-shaped structure portion is formed in a conical shape or a truncated cone shape. The planar probe according to any one of claims 1 to 3, wherein the substrate, the columnar structure portion, and the conical structure portion are integrally formed of the same material. The planar probe according to claim 4, wherein the same material is quartz or optical glass. The planar probe according to any one of claims 1 to 3, wherein the columnar structure portion and the conical structure portion are made of the same material and different from the substrate. The planar probe according to any one of claims 1 to 3, wherein the substrate is backed by a translucent support material provided on the back side thereof. The planar probe according to any one of claims 1 to 7, further comprising a protective wall formed around the protrusion by the same material as the protrusion on the surface side of the substrate. The planar probe according to any one of claims 1 to 8, further comprising a light shielding film that covers at least a slope portion of the conical structure portion. The flat surface according to any one of claims 1 to 9, further comprising a condensing function unit that is formed on a back surface side of the substrate or the support material and collects light incident from the back surface side on a root portion of the columnar structure portion. Type probe. The planar probe according to any one of claims 1 to 10, wherein a plurality of the protrusions are arranged in an array on the surface side of the substrate. Forming a columnar structure portion made of a translucent material on a substrate having translucency;
The periphery of the columnar structure on the substrate is etched with the same etching solution or etching gas as the material of the columnar structure, and is made of a material having a lower refractive index than the material of the columnar structure, and is etched from the material of the columnar structure. A process of embedding a fast-rate embedding material;
Etching the columnar structure portion and the filling material by isotropic etching to form a conical structure portion on the columnar structure portion;
A method of manufacturing a planar probe including: A light source that emits light to irradiate the optical recording medium;
The planar probe according to any one of claims 1 to 9 or 11, which is disposed so that a tip of a protrusion is positioned on the optical recording medium side;
Condensing means for condensing the light emitted from the light source at the base of the protrusion;
An optical pickup device comprising: A light source that emits light to irradiate the optical recording medium;
The planar probe according to claim 10, wherein the planar probe is disposed so that a tip of the projection is positioned on the optical recording medium side, and condenses the light emitted from the light source on a root portion of the projection by a condensing function unit;
An optical pickup device comprising:

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