JP3157754B2 - Planar probe and method of manufacturing the same - Google Patents

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 planar probe used for performing optical recording by evanescent light, for example.

[0002]

2. Description of the Related Art An optical recording medium on which information is recorded / reproduced by irradiating light has an optical recording layer, a dielectric layer,
Various functional films such as a reflective layer are formed. As the optical recording layer, a material layer having a shape change or an optical change due to light irradiation, or a material layer having a magneto-optical effect such as a rare earth transition metal amorphous alloy thin film is provided.

Conventionally, information recording on these optical recording layers has been performed by condensing laser light with a condenser lens and irradiating the optical recording layer. In the optical recording layer irradiated with the laser light, magnetization reversal occurs in the laser spot due to a shape change, an optical change, or a decrease in coercive force, and pits are formed. By forming such pits in a pattern corresponding to the information signal, the information signal is recorded on the recording medium. In order to reproduce an information signal recorded on a recording medium, laser light is focused on an optical recording layer by a condenser lens, and the light intensity of the reflected light is detected. Since the intensity of the reflected light from the optical recording layer is different between the portion where the pits are formed and the portion where the pits are not formed, the pit pattern on the optical recording layer is detected as a change in the intensity of the reflected light, thereby reproducing the information signal. Is done.

The recording density in such optical recording is determined by the size of a pit. In the case of a recording / reproducing system in which laser light is condensed by a condensing lens as described above, light is condensed on an optical recording layer. The size of the pit is determined by the laser spot diameter. However, the laser spot diameter cannot be made smaller than k · λ / NA (k: constant, λ: wavelength of light, NA: numerical aperture of the lens) due to the diffraction limit of light, and therefore the laser light is focused on the condenser lens. As long as a system for condensing light is used, there is a limit in increasing the density of an optical recording medium.

Therefore, a method using a near field is considered to be promising as an optical recording / reproducing method which is not limited by the diffraction limit of light.

[0006] The evanescent light is an electromagnetic wave generated in a very close area (near field) where the distance from the surface of the object is smaller than the wavelength of the light when the back surface of the object is irradiated with light under the condition of total reflection. If this evanescent light is generated, for example, at the tip of a sharp shape having a radius of curvature smaller than the wavelength of light, pits can be formed with a diameter smaller than the minimum diameter limited by the diffraction limit of light.

As a method of performing optical recording using such evanescent light, an optical fiber probe having a tapered sharpened portion having a core protruding from a clad at one end of an optical fiber is used. A method has been proposed.

In order to record an information signal on an optical recording medium with the optical fiber probe, the tip of the sharp end of the optical fiber probe is brought close to the optical recording medium, and laser light is introduced from the other end of the optical fiber probe. The introduced laser light propagates in the core and is guided to the sharp part, and evanescent light is generated at the tip of the sharp part. A pit is formed by irradiating the optical recording layer with the evanescent light. To reproduce an information signal, the optical recording layer is irradiated with evanescent light generated at the tip of the sharp portion, and scattered light generated on the optical recording layer is detected. In optical recording using such an optical fiber probe, high-density recording of 1 Tbit / in ² is possible if the opening diameter at the tip of the sharp portion of the optical fiber probe is 30 nm or less.

[0009]

However, the optical fiber probe has a very small sharp portion and is mechanically fragile. Therefore, when the medium is scanned at high speed, a trouble such as breakage of the sharp portion occurs. Further, since light loss is large at a sharp portion having a diameter smaller than the wavelength of light, a sufficient amount of reproduced light cannot be obtained at a high scanning speed. For these reasons, the optical recording / reproducing method using the optical fiber probe has a problem that the scanning speed cannot be increased freely.

[0010] Among these problems, the optical loss caused by the optical fiber probe can be reduced by increasing the inclination angle of the sharp portion, but the resolution decreases if the inclination angle of the sharp portion is increased.

Therefore, the sharp portion is sharpened at two-step inclination angles, a high resolution is obtained by reducing the inclination angle on the front end side, and the light is increased by increasing the inclination angle at the second step from the front end side. There has been proposed an optical fiber probe capable of suppressing loss.

In addition, there has been reported an optical fiber probe in which an optical fiber probe is coated with a metal film to increase the pumping efficiency of the lowest-order mode among the modes inside the probe.

However, it is difficult to greatly increase the light intensity of the optical fiber probe even if these measures are taken. In addition, no effective countermeasures have been taken for problems of mechanical brittleness and scanning speed, which makes optical recording using evanescent light difficult.

Therefore, the present invention has been proposed in view of such a conventional situation, and is capable of efficiently generating evanescent light, has excellent mechanical strength, and has an optical recording / reproducing optical head. An object of the present invention is to provide a method of manufacturing a planar probe that can reproduce a large amount of information in a short time when used.

[0015]

In order to achieve the above-mentioned object, a method of manufacturing a flat probe according to the present invention comprises the steps of forming a thermal oxide film on both main surfaces of a substrate, A thermal oxide film patterning step of removing the thermal oxide film of the portion corresponding to the probe on the surface and removing the thermal oxide film of the probe formation region on the other surface of the substrate;
A recess forming step of forming a pyramid-shaped recess at an opening angle smaller than the final opening angle by anisotropic etching in a portion of the substrate from which the thermal oxide film has been removed, and the other surface of the substrate An opening is formed by opening the apex of the conical recess facing the etched surface, a light shielding film is formed on the substrate surface facing the opening, and anisotropic etching is performed. The opening angle adjusting step of expanding the opening angle of the conical concave portion to the final opening angle, and accommodating the spherical lens in the concave portion by applying a dispersion liquid in which the spherical lens is dispersed on one surface of the substrate. A lens accommodation step, wherein the etching is performed from one surface of the substrate in the concave portion forming step and the opening angle adjusting step, and the other surface of the substrate is etched in the opening forming step from the other surface of the substrate. And ball ren The distance between the focal point k, the focal length of the spherical lens is taken as f of, | k | and forming a recess having a shape that satisfies the ≦ f / 4 the relationship.

[0016]

[0017]

[0018]

[0019]

[0020]

[0021]

In the flat probe manufactured by the manufacturing method of the present invention, an optical opening is formed by a light-shielding film. The aperture diameter and the position of the spherical lens can be freely controlled. Accordingly, a planar probe having desired characteristics is manufactured.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the present invention will be described.

The planar probe according to the present embodiment is shown in FIG.
As shown in FIG. 2, a conical through-hole 2 is formed in a substrate 1, and a microsphere lens 4 is accommodated in the through-hole 2. In this planar probe, light is emitted from the bottom surface side (upper side in the figure) of the cone of the through-hole 2, and evanescent light is generated at the vertex side of the cone. In other words, the vertex side of the cone becomes the opening 3 where the evanescent light is generated (hereinafter, the vertex side opening is simply referred to as an opening).

The substrate 1 is not particularly limited. For example, a silicon substrate or the like is used. The through hole 2 formed in the substrate 1 is formed in a conical shape, and may be a cone or a pyramid. The opening 3 of the conical through-hole 2 may coincide with the vertex of the cone, and the substrate surface facing the opening 3 is formed so as to recede from the surface including the virtual vertex of the cone. Accordingly, the opening 3 may be shifted toward the spherical lens 4 from the virtual vertex. The opening 3 has a diameter of several nm to 20 nm to generate evanescent light.
It is about 0 nm.

A microsphere lens 4 is accommodated in the through hole 2. The microsphere lens 4 is for condensing the light taken into the through-hole 2, and the light is reduced by the microsphere lens 4 to about half the wavelength of the light determined by the refractive index of the substrate 1. It is possible to narrow down. In addition, ball lens 4
Since it is centrally symmetric, there is no need to consider the direction, and therefore, it can be easily accommodated in the concave portion by, for example, applying a dispersion liquid in which a spherical lens is dispersed to the substrate surface.

In this planar probe, the through-holes 2 in which such microsphere lenses 4 are accommodated respectively correspond to the probes 5, and this probe 5 is formed singly on the substrate 1 or on a two-dimensional plane. May be formed in an array by forming a plurality. In the case of a planar probe array in which a plurality of probes 5 are formed, the array may be a grid pattern in which a plurality of probes 5 are arranged at equal intervals in a row direction and a column direction as shown in FIG. Alternatively, as shown in FIG. 3 (b), a row or column may be obliquely inclined and arranged in a diamond shape. The number of the probes 5 varies depending on the use of the planar probe, but when used for optical recording, 100 or more probes are provided.

In this planar probe, the light-shielding film 6 may be formed on the surface of the substrate 1 on the side of the opening 3 or on the surface on the opposite side as shown in FIG. This light-shielding film is a necessary structure particularly when a material that transmits light is used for the substrate. When the light-shielding film 6 is provided on the substrate surface, an opening is also formed in the light-shielding film 6 at a position corresponding to the opening 3 of the substrate, and the opening surrounded by the light-shielding film 6 becomes an actual optical opening. Therefore, in this case, it is desirable that the diameter of the optical opening formed by the light-shielding film is about several nm to 200 nm. As the light shielding film 6, for example, a metal thin film is provided.

The above is the basic configuration of the flat probe. In the planar probe of this embodiment, the focal point of the spherical lens 4 is restricted to an appropriate range.

That is, FIG. 5 shows a schematic view of a probe formed on a planar probe. In FIG. 5, the substrate surface facing the opening is receded from a surface A which is parallel to the substrate surface and includes a virtual vertex of the conical through-hole t (hereinafter, this surface is referred to as a vertex surface) A. It shows the case where it is formed as follows.

In the planar probe of this embodiment, the distance between the plane B including the substrate surface facing the opening 3 (hereinafter referred to as the opening surface) B and the focal point F of the spherical lens 4 is k,
When the focal length of the spherical lens 4 is f, it is designed to satisfy the relationship | k | ≦ f / 4. When such a relationship is satisfied, the light condensed by the spherical lens 4 is focused near the opening 3, and evanescent light with a light intensity 10 times or more lower than that of the case where no spherical lens is used below the opening 3. Can occur. For example, when a silicon substrate and a quartz sphere lens are used, when the diameter of the opening 3 is 600 nm and the diameter of the sphere is 10 μm, 16 times light intensity can be obtained.
Here, when k is a positive value, the focal point F is shifted to the spherical lens 4 side from the opening surface B, and when k is a negative value, the focal point F is shifted from the opening surface B to the through hole. 2 is shifted to the virtual vertex t side.

[0032] and the opening face B, a distance k between the focal point F of the spherical lens 4, and the focal length f of the spherical lens 4, a ratio n ₁ of the refractive index n ₂ of the refractive index n ₁ and the medium of the spherical lens / N ₂ , the opening angle θ _f of the through-hole 2 and the distance m between the opening surface B and the vertex surface A, so that | k | ≦
These parameters may be adjusted so as to satisfy the relationship of f / 4.

That is, first, the focal length f of the spherical lens is
Determined by the ratio n ₁ / n ₂ of a refractive index n ₂ of the refractive index n ₁ and the medium of the radius r and the spherical lens 4 in the spherical lens 4, when _{n 1 / n 2 = n,} f = nr / 2 (n- 1) Expression 1

On the other hand, the distance P between the imaginary vertex t of the through hole 2 with the center c of the spherical lens 4 is determined by the radius r and the through-hole 2 of the divergence angle theta _f of the spherical lens, P = r / sin (θ f /2)...Expression 2 Here, the spread angle θ _{f of the} through hole 2 referred to here
Corresponds to the taper angle of the cone when the through hole 2 is conical. Further, in the case of a pyramid shape, taking a quadrangular pyramid 20 as shown in FIG. 6 as an example, a virtual cone 22 having its inscribed circle 21 as a base and a virtual vertex t of the pyramid 20 as a vertex.
Corresponds to the taper angle θt.

Since the distance k between the aperture surface B and the focal point F of the spherical lens 4 is k = P-fm, if P and f are respectively replaced by the above equations 1 and 2, then k = r / sin (θ _f / 2) over nr / 2 (n-1) -m ··· equation 3 is obtained, so that the absolute value of the value obtained by this equation 3 is f / 4 or less, the spherical lens the refractive index of the refractive index n ₁ and the medium n2, may be set the distance m of the opening angle theta _f and aperture plane B and the vertex surface a of the through hole. Note that in a normal use environment, the medium is air, and in that case, the refractive index n ₂ is 1.

Here, a method of adjusting the distance k when a silicon substrate is used as a substrate will be described as an example. Before that, a manufacturing process for manufacturing a planar probe from this silicon substrate will be described.

In order to manufacture a planar probe, as shown in FIG. 7, a silicon substrate 10 cut out so that its main surface side is a (100) crystal lattice plane is prepared, and this silicon substrate 10 is subjected to a thermal oxidation treatment. Thus, thermal oxide films 11 are formed on both main surfaces as shown in FIG.

Then, as shown in FIG.
1 is coated with a photoresist 12 and a predetermined area is exposed to form a resist mask having an opening corresponding to the probe on one main surface (first main surface) 10a side as shown in FIG. The resist mask 12 is formed on the other main surface (second main surface) 10b side so as to cover only the portion excluding the probe formation region, that is, only the peripheral portion.

Next, the resist mask 12
The thermal oxide film 11 on which is formed is subjected to a treatment with a buffered hydrogen fluoride solution, and as shown in FIG.
The portion of the thermal oxide film 11 corresponding to the opening 2 is removed, and then the resist mask 12 is peeled off.

Next, the silicon substrate 10 is subjected to anisotropic etching with an aqueous alkali solution. As the alkaline aqueous solution used for this etching, for example, a liquid temperature of 80
A 10% KOH aqueous solution at a temperature of 10 ° C. is used.

By such anisotropic etching, as shown in FIG. 12, a quadrangular pyramid surrounded by a slope of a (111) crystal lattice plane is formed on a portion of the first main surface 10a where the thermal oxide film 11 is not formed. A concave portion 13 is formed. Note that the opening angle θf of the quadrangular pyramid-shaped recess formed here corresponds to the angle formed by the opposing (111) crystal lattice planes.
2 ゜.

Subsequently, as shown in FIG. 13, the second main surface 10b of the silicon substrate 10 is etched to make the substrate 10 thinner, and the quadrangular pyramid-shaped concave portion 1 is formed.
The etching is continued until the vertex of No. 3 opens toward the second main surface 10b. Then, as shown in FIG. 14, a metal thin film 15 such as gold is formed by a thin film forming technique such as sputtering on the second main surface 10b in which the openings 14 are formed by etching as described above. The distance m between the opening surface B and the vertex surface A of the flat probe to be manufactured is controlled by the etching amount in this step.

Finally, isopropyl alcohol in which fine glass beads (spherical lens) are dispersed is prepared, and is dropped on the first main surface. Thus, the beads 16 are accommodated in the respective recesses 13 on the first main surface 10a as shown in FIG. 15, and the planar probe shown in FIG. 4 is completed.

The flat probe is manufactured from the silicon substrate by the above-described steps. In this case, the opening angle θ of the through hole 2 is set.
_f is determined by an angle 70.2 ° formed between mutually facing (111) crystal lattice planes. Therefore, the distance k between the aperture plane B and the focal point F of the spherical lens 4 is adjusted within ± f / 4 by controlling other parameters.

Here, when the distance m between the opening surface B and the vertex surface A is 0, that is, when the opening 3 coincides with the vertex t of the cone, the light collected by the spherical lens 4 Focusing is performed when 2-2 / n = sin (θ _f / 2) is satisfied, and when θ _f is 70.2 °, the refractive index ratio n is 1.4. . When the refractive index ratio n has such a value, the highest light intensity can be obtained below the opening.

Further, even if the light condensed by the spherical lens 4 does not focus on the aperture 3, the aperture B
If the distance k between the lens and the focal point F of the spherical lens 4 is within the range of | k | ≦ f / 4, a sufficient light intensity can be obtained below the opening 3. These conditions are satisfied when θ _f = 7.
At 0.2 °, the relative refractive index n is 1.27 to 1.55
Is the case.

That is, in the plane probe using the silicon substrate, when the distance m between the opening surface B and the vertex surface A is set to 0, the appropriate range of the relative refractive index n is 1.27 to 1.55. 4 is the optimum value of the relative refractive index. Relative refractive index n
Is 1.4, the focal point F of the spherical lens 4 can be completely matched with the opening.

In order to set the relative refractive index n in such an appropriate range, when the medium is air, n ₂ = 1, so that the refractive index n ₁ of the spherical lens 4 is 1.27 to ₁ . You need to select 55. As a material of such a lens,
Quartz glass (n ₁ = 1.46) is used. When a spherical lens made of this quartz glass is used, k = f / 10, and the focal point of the spherical lens can be brought closer to the aperture surface. .

The refractive index n ₁ of the spherical lens 4 can be adjusted to various values by adding an additional element in principle.
It is difficult to set the optimum value to 1.4 due to a problem in producing microspheres. Therefore, it is desirable to control and fine-tune other parameters together with the selection of the spherical lens 4.

For example, the focal length may be adjusted by disposing a material having a refractive index different from that of air in the space of the conical through hole 2. In this case, as shown in FIG. 16, the material 7 for adjusting the focal length is disposed in a space on the bottom side of the spherical lens 4 of the through hole 2 so as to be in contact with the spherical lens surface, or as shown in FIG. It is effective to arrange in the space near the opening 3 as described above. The position of the focal point can be arbitrarily adjusted by selecting the shape of the material 7 and the refractive index.

The distance k between the aperture B and the focal point F of the spherical lens may be adjusted by retracting the aperture B with respect to the vertex A. This is because in the previous manufacturing process
It can be controlled by the amount of etching of the second main surface performed after the formation of the conical concave portion.

However, when the opening surface B is retracted from the vertex surface A, as the distance m between the opening surface B and the vertex surface A increases, the opening diameter of the opening 3 increases. Therefore, in such a case, for example, as shown in FIG. 18, a light-shielding film 6 is formed so as to cover the substrate surface facing the opening 3 and the opening 3.
An optical opening surrounded by the light shielding film 6 may be formed by forming the minute hole 8 at a position substantially corresponding to the center of the opening 3 of the light shielding film 6.

Such a planar probe is manufactured by changing the above-described manufacturing process as follows.

That is, in the step of forming a conical concave portion,
To a final plan small opening angle theta _f than the probe forms a conical recess 13. And the second main surface 1
0b is etched to form a conical recess 13.
The etching is continued until the vertex of the substrate opens toward the second main surface 10b. Thereafter, a metal thin film 15 serving as a light shielding film is formed on the second main surface 10b. FIG. 19 shows a state in which the conical concave portion 13, the opening, and the metal thin film are formed. Then, as shown in FIG. 20, by anisotropic etching from the first major surface 10a side, widening the open angle theta _f of the cone-shaped recess 13 until the final angle. Finally, isopropyl alcohol in which fine glass beads are dispersed is applied to the first main surface 10a.
The flat probe shown in FIG. 18 is produced by dropping the above liquid crystal and storing the beads in the concave portions 13 respectively.

In each of the above-described various planar probes, the focus of the light condensed by the spherical lens in each probe is regulated to an appropriate position, and a near field having a large light intensity can be generated below the opening. .

Therefore, for example, when used as an optical head for performing recording and reproduction using evanescent light, good recording and reproduction characteristics can be obtained.

Further, since it does not have a mechanically fragile structure such as a sharp portion, breakage hardly occurs even when a high-speed sweep is performed.

Further, when this planar probe is used as an optical head for optical recording / reproducing in the form of a plurality of probes formed, signal detection is performed by each probe, so that a plurality of information signals are reproduced at the same time and the sweep speed is reduced. A lot of information is reproduced in a short time at the latest.

[0059]

As is apparent from the above description, the method of manufacturing a planar probe according to the present invention comprises a step of forming a thermal oxide film on both main surfaces of a substrate, and a method of forming a thermal oxide film on one surface of the substrate. A thermal oxide film patterning step of removing a thermal oxide film in a portion corresponding to the probe and removing a thermal oxide film in a probe forming region on the other surface of the substrate; and a portion of the substrate where the thermal oxide film is removed on one surface Then, a recess forming step of forming a conical recess at an opening angle smaller than the final opening angle by anisotropic etching, and etching on the other surface of the substrate, and apex of the conical recess is performed by this etching. Forming an opening facing the surface, forming a light-shielding film on the substrate surface facing the opening, and forming an opening angle of the conical recess by anisotropic etching. Opening up to An angle adjusting step and a lens accommodating step of accommodating a spherical lens in the concave portion by applying a dispersion liquid in which a spherical lens is dispersed on one surface of the substrate, and the concave portion forming step and the opening angle adjusting step By etching from one surface of the substrate and etching from the other surface of the substrate in the opening forming step, the distance between the other surface and the focal point of the spherical lens is k, and the focal length of the spherical lens is f.
In this case, since a concave portion having a shape satisfying the relationship of | k | ≦ f / 4 is formed, an optical opening is formed by the light-shielding film. The opening diameter of the optical opening and the position of the spherical lens can be freely controlled by the opening angle. Therefore, the method of manufacturing a flat probe according to the present invention can manufacture a flat probe having desired characteristics. The flat probe manufactured in this manner has a conical through-hole formed by gradually reducing the opening from one surface of the substrate to the other surface, and is formed to be accommodated in the through-hole. A spherical lens and a probe in which a material having a refractive index different from that of air is disposed in a conical space of the through hole, and the other surface facing the opening on the vertex side of the through hole. When the distance between the plane including the lens and the focal point of the spherical lens is k and the focal length of the spherical lens is f, the relationship of | k | ≦ f / 4 is satisfied, and the light intensity is close to the lower side of the opening. A field can be created. That is, according to this planar probe, light incident from one surface on the bottom side of the conical through-hole is transmitted from the other surface on the vertex side of the conical through-hole to the back surface of the recording medium under the condition of total reflection. When the light is irradiated, the light can be emitted as evanescent light generated in a near field whose distance from the surface of the recording medium is smaller than the wavelength of the light. Therefore, for example, when used as an optical head that performs recording and reproduction using evanescent light, good recording and reproduction characteristics can be obtained.

Further, since it does not have a mechanically fragile structure such as a sharp portion, breakage hardly occurs even when a high-speed sweep is performed.

Further, when this planar probe is used as an optical head for optical recording and reproduction in the form of a plurality of probes formed, signal detection is performed by each probe, so that a plurality of information signals are reproduced simultaneously and the sweep speed is reduced. A lot of information can be reproduced in a short time at the latest.

[0062]

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing an example of a planar probe to which the present invention is applied.

FIG. 2 is a plan view of the flat probe.

FIGS. 3A and 3B show examples of arrangement of probes formed on a planar probe, in which FIG. 3A is a schematic diagram showing probes arranged in a grid pattern, and FIG. 3B is a diagram showing probes arranged in a diamond shape. FIG.

FIG. 4 is a schematic sectional view showing another example of the planar probe to which the present invention is applied.

FIG. 5 is a schematic view showing a probe formed on the flat probe.

FIG. 6 is a schematic diagram for explaining an opening angle of a pyramid-shaped through hole.

FIG. 7 is a cross-sectional view illustrating a method of manufacturing a planar probe in the order of steps and illustrating a silicon substrate used for forming the probe.

FIG. 8 is a sectional view showing a thermal oxide film forming step.

FIG. 9 is a cross-sectional view showing a photoresist coating step.

FIG. 10 is a sectional view showing a pattern of a formed resist mask.

FIG. 11 is a sectional view showing a thermal oxide film etching step.

FIG. 12 is a cross-sectional view showing a recess forming step.

FIG. 13 is a cross-sectional view showing an opening forming step.

FIG. 14 is a cross-sectional view showing a light-shielding film forming step.

FIG. 15 is a cross-sectional view showing a microlens accommodation step.

FIG. 16 is a schematic cross-sectional view showing a state in which a material for adjusting a focal length is arranged in a space on the bottom surface side of a probe having a conical through hole.

FIG. 17 is a schematic cross-sectional view showing a state in which a material for adjusting the focal length is arranged near the opening of the conical through hole.

FIG. 18 is a schematic sectional view showing a planar probe in which an optical opening is formed by a light shielding film.

FIG. 19 is a schematic cross-sectional view showing a step of manufacturing the flat probe of FIG. 18 and showing a concave part forming step and a light shielding film forming step.

FIG. 20 is a schematic cross-sectional view showing a step of adjusting the opening angle of the concave portion.

[Explanation of symbols]

1 substrate, 2 recess, 3 opening, 4 lens, 5 probe, 6 light shielding film

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-5-45504 (JP, A) JP-A-7-134202 (JP, A) JP-A-5-164968 (JP, A) JP-A-5-164968 100168 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G11B ^7/ 12-7/22 G01N 13/14 G02B 3/00

Claims (1)

(57) [Claims] A thermal oxide film forming step of forming thermal oxide films on both main surfaces of a substrate; removing a thermal oxide film corresponding to a probe on one surface of the substrate and a probe on the other surface of the substrate; A thermal oxide film patterning step of removing the thermal oxide film in the formation region, and an anisotropic etching on the one side of the substrate where the thermal oxide film has been removed, at an opening angle smaller than the final opening angle. A concave portion forming step of forming a conical concave portion; an opening forming step of performing etching on the other surface of the substrate to open a vertex of the conical concave portion to face the etched surface; and forming an opening on the substrate surface facing the opening portion. A light-shielding film forming step of forming a light-shielding film, an opening angle adjusting step of increasing the opening angle of the conical concave portion to a final opening angle by anisotropic etching, and a spherical lens dispersed on one surface of the substrate. Dispersion applied A lens accommodating step of accommodating a spherical lens in the concave portion by performing etching from one surface of the substrate in the concave portion forming step and the opening angle adjusting step, and the other side of the substrate in the opening forming step. By etching from the surface,
When the distance between the other surface and the focal point of the spherical lens is k and the focal length of the spherical lens is f, a concave portion having a shape satisfying the relationship | k | ≦ f / 4 is formed. Manufacturing method of planar probe.