JP2002148174A - Near field probe and proximity field probe manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a near field probe little generating background light. SOLUTION: This near field probe 10 has a cantilever lever part 14 extending from a support part 12, and the lever part 14 has a probe 16 at the tip. The leer part 14 is, for example, formed by a silicon nitride film 22 and a scatterer forming thin film 24, and the scatterer body forming thin film 24 includes a spherical scatterer body 26 in a part positioned at the tip of the probe 16. The near field probe 10 is manufactured by coating the surface of the probe of a SiN-made AFM cantilever generally available from the market with the scatterer forming thin film 24, and radiating active light such as a laser beam, an ion beam or the like from the axis of the probe 16 to be focused on the tip of the probe 16, and a scatterer 26 is formed in the interior of the scatterer forming thin film 24 by irradiation of active light. The scatterer forming thin film 24 is, for example, a multiplayer film of ZnS-SiO2/Ag2/ZnS-SiO2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a near-field probe,
The present invention relates to a near-field microscope using the same.

[0002]

2. Description of the Related Art A scanning probe microscope (SPM) scans a probe along a sample surface while detecting an interaction acting between the probe and the probe when the probe approaches the sample surface. It is a device that performs two-dimensional mapping of the action, and is represented by, for example, a scanning tunneling microscope (STM), an atomic force microscope (AFM), a magnetic microscope (MFM), and a scanning near-field microscope (SNOM).

[0003] In particular, SNOM has been used since the late 1980s as an optical microscope having a resolution exceeding the diffraction limit by detecting an evanescent field, to measure the fluorescence of a biological sample and to evaluate photonic materials and elements (dielectric light guide). (Evaluation of various wave path characteristics, measurement of emission spectrum of semiconductor quantum dots, evaluation of various characteristics of semiconductor surface emitting devices, etc.)
Development is being actively pursued for application to SN
The OM is a device that basically brings a sharp probe close to a sample while irradiating the sample with light, and detects a light field (near field) near the sample.

US Pat. No. 5,272,330, issued to Betzig et al. On Dec. 21, 1993, discloses that evanescent light is introduced into a fine opening at the tip of a probe by introducing light into the probe having a thinned tip. A SNOM that generates a field, makes an evanescent field come into contact with the sample, detects light generated by the contact between the evanescent field and the sample with a photodetector arranged under the sample, and performs two-dimensional mapping of transmitted light intensity. Has been disclosed.

[0005] Van Hulst et al. Succeeded in simultaneous observation of AFM and SNOM by using an AFM cantilever made of SiN as a SNOM probe and scattering the evanescent field generated on the sample surface by a dark-field illumination optical system by the tip of the probe. (Appl. Phys. Lett. 62, 461 (1
993)).

The method of measuring the optical characteristics of a sample surface by using the high scattering characteristics of the tip of a metal or a dielectric material having a high refractive index has less dimming and is stronger than an aperture probe represented by a conventional fiber probe. Since signal light can be obtained, high resolution and improvement in S / N can be achieved, which has attracted attention in recent years.

Further, Bachelot et al. Succeeded in observing an opaque sample by irradiating light from the probe side for scanning the sample and using a reflection mode scattering SNOM that detects optical information on the sample surface near the tip of the probe. (Opt. Lett.
20. 1924 (1995)). Furthermore, Sasaki et al. Perform high-resolution observations using reflection mode scattering SNOM (J. App.
l.Phys. 85. 2026 (1999)).

[0008]

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

In a conventional scattering SNOM using a cantilever probe (scattering probe) for an AFM having no minute aperture, it is ideal to detect scattered light only from a sharply pointed probe tip. (Support portion) becomes a scatterer and generates background light. This reduces the contrast of the signal that should be detected.

Generally, means for reducing background light include:
It is effective to use a dark-field illumination optical system for generating an evanescent field on the surface of the sample placed on the critical angle prism, but it is effective for an opaque sample and for reflection mode scattering S.
Not applicable to NOM.

Attempts have also been made to adhere a small spherical scatterer such as gold colloid to the tip of the probe. This is because the scattering efficiency of the scatterer provided at the tip of the probe of the cantilever is larger than the scattering efficiency of the supporting portion that generates the background light, and therefore, the scattering efficiency is higher than that of the conventional SNFM using the cantilever probe for AFM. The effect of light can be reduced.

However, since a method of fixing only a single particle of the scatterer to the tip of the probe has not been established, it is difficult to produce a good probe with good reproducibility. In addition, such a probe is used when measuring a sample with severe irregularities.
The scatterer may be removed during scanning, and there is a problem that it cannot withstand long-time use.

Further, the size of the scattered light spot depends on the size of the scatterer. Therefore, when wide and fast scanning is required, it is preferable to use a probe having a large scatterer, and when performing high-resolution observation of a specific region, it is preferable to use a probe having a small scatterer. However, in the conventional manufacturing method, it is necessary to arrange a scatterer having a desired size, which is very troublesome.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and an object of the present invention is to provide a scattering probe that generates less background light. And to provide a method for producing the same with good reproducibility.

[0015]

SUMMARY OF THE INVENTION The present invention relates to a probe used in a near-field microscope or a near-field optical recording device,
The tip and side surfaces of the probe are coated with a material that exhibits a thermally non-linear response, and the coating has a scatterer formed by causing a chemical reaction thermally at the tip portion. .

The present invention also relates to a probe used for a near-field microscope or a near-field optical recording device, wherein the tip and side surfaces of the probe are coated with a material containing silver oxide, and the coating is formed at the tip portion. It has a scatterer formed by causing a chemical reaction thermally.

The present invention is also a method of manufacturing a probe used in a near-field microscope or a near-field optical recording device,
A step of coating the tip and side surfaces of the probe with a substance exhibiting a thermally non-linear response, and a step of forming a scatterer by causing a chemical reaction at the tip portion of the coated probe. Features.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [First Embodiment] As shown in FIG. 1, a near-field probe 10 has a cantilever lever 14 extending from a support portion 12, and the lever portion 14 is provided at the tip. It has a probe 16. The lever portion 14 includes, for example, a silicon nitride film 22 and a scatterer forming thin film 24. The scatterer forming thin film 24 includes a spherical scatterer 26 at a portion located at the tip of the probe 16.

Such a near-field probe 10 is manufactured, for example, as follows.

First, a structure not including the scatterer forming thin film 24 in FIG. 1 is prepared. Such a structure is known as an AFM cantilever made of SiN manufactured using a silicon planar process, can be manufactured by a known technique, and is generally available on the market.

Next, a scatterer forming thin film 24 is coated on at least the surface of the probe of the AFM cantilever. The scatterer forming thin film 24 is usually transparent on the entire side surface of the probe,
When irradiated with light of a certain intensity or more, it has a property of being thermally changed chemically to form a scatterer. Scatterer-forming thin film 24
Is, for example, a three-layer ZnS—SiO ₂ / A
It is a multilayer film of g ₂ O / ZnS—SiO ₂ .

FIGS. 4A and 4B respectively show a ZnS-SiO ₂ film on a normal glass substrate with a sputtering apparatus.
nm, Ag ₂ O 15 nm, ZnS—SiO ₂ 20 n
m, transmission images before and after laser irradiation when a substrate formed in this order was irradiated with a YAG-SHG laser at 1.5 mW for 15 seconds. As a result of irradiating the laser beam to the upper left transparent portion of FIG. 4A, the scatterer shown in FIG. 4B was formed. The black object at the lower right is dust attached to the glass.

This means that when a certain amount or more of light is irradiated, Ag aggregation occurs due to the thermal action of the light and a scatterer is formed. This is a known technique reported by Fuji et al. (ISOM / ODS '99, Postdedli
ne TuD29).

Next, as shown in FIG. 2, the active light 32 is applied to the AFM cantilever 10 'coated with the scatterer forming thin film 24 so as to focus on the tip of the probe 16 of the cantilever 10'. Is irradiated from the axis of the probe 16.
As the active light 32, a laser, an ion beam, or the like is used.

The active light 32 applied to the probe 16 is shown in FIG.
As shown in FIG. 7, the intensity distribution has the maximum intensity at the vertex of the probe 16. The intensity of the active light 32 is adjusted so that only the central portion of the light intensity distribution incident on the tip of the probe 16 exceeds the light intensity that causes a chemical change in the scatterer forming thin film 24. As a result, a scatterer 26 having a size corresponding to the intensity of the active light 32 is formed inside the scatterer forming thin film 24 at the apex of the probe 16.

A scatterer 26 formed by irradiation with active light
Depends on the scatterer forming thin film 24 and the intensity of the active light. In other words, when the thick scatterer-forming thin film 24 is irradiated with high-intensity active light, the area where chemical change occurs is wide,
Large scatterers are formed. On the other hand, when the thin scatterer forming thin film 24 is irradiated with low intensity active light, a small scatterer is formed.

Therefore, by covering the probe with the thick scatterer-forming thin film 24 and irradiating the tip thereof with strong active light, a probe having a large scatterer suitable for observation requiring a wide range of fast scanning is manufactured. Is done. Further, by covering the probe with a thin scatterer-forming thin film 24 and irradiating the tip portion with weak active light, a probe having a small scatterer suitable for observation for high-resolution observation of a specific region is manufactured. You. That is, a probe suitable for the observation purpose can be easily produced.

In the present embodiment, unlike the conventional method of physically bonding the scatterer to the tip of the probe, the probe is covered with a scatterer-forming thin film, and the tip is irradiated with active light. A scatterer is formed. Therefore, the scatterer can be easily and reproducibly arranged at the tip of the probe. Furthermore, since the scatterer is formed inside the scatterer-forming film and does not protrude from the probe surface, even when observing a sample having severe irregularities, the scatterer is not removed during scanning, so that the scatterer cannot be removed for a long time. Can be used.

In the above-described embodiment, the scatterer is formed by irradiating the active light 32 from the axis of the probe 16 as shown in FIG. Not limited to The active light only needs to be irradiated so as to focus on the tip of the probe 16 of the cantilever 10. For example, as shown in FIG. 5, the irradiation of the active light is performed from the side of the probe 16. Is also good.

[Second Embodiment] A near-field probe manufacturing method according to a second embodiment will be described with reference to FIG. The near-field probe manufactured in the present embodiment has the same structure as the near-field probe described in the first embodiment, and the same members as those in the first embodiment have the same reference numerals in FIG. Reference numerals are used, and a detailed description thereof will be omitted.

As in the first embodiment, first, the AFM
Prepare a cantilever and at least the surface containing the probe 16
Is covered with a scatterer forming thin film 24. Scatterer-forming thin film 24
Is, for example, ZnS-Si, as in the first embodiment.
O_Two/ Ag_TwoO / ZnS-SiO _TwoIs a multilayer film.

Next, as shown in FIG.
The tip of the probe 16 of the cantilever is brought into contact with the heat supply source 42, and only the tip of the probe of the scatterer forming thin film 24 undergoes a chemical change thermally. As a result, the near-field probe 10 in which the scatterer 26 is formed inside the scatterer-forming thin film 24 at the tip of the probe 16 is formed.

The size of the scatterer 26 to be formed depends on the temperature of the heat source 42, the contact time, the thickness of the scatterer forming thin film 24,
It depends on the radius of curvature of the tip of the probe 16. That is, these parameters are determined according to the near-field probe that is intended to be produced.

In the present embodiment, unlike the conventional method of physically bonding the scatterer to the tip of the probe, the probe is covered with a scatterer-forming thin film, and the tip is brought into contact with a heat supply source. Is formed. Therefore, it is possible to easily arrange the scatterer at the tip of the probe with good reproducibility. Furthermore, since the scatterer is formed inside the scatterer-forming film and does not protrude from the probe surface, even when observing a sample having severe irregularities, the scatterer is not removed during scanning, so that the scatterer cannot be removed for a long time. Can be used.

In the above-described first and second embodiments, a method of manufacturing a near-field probe based on an AFM cantilever manufactured by using a silicon planar process has been described. The application destination of is not limited to this. That is, the near-field probe manufacturing method of the present invention may be applied to, for example, an optical fiber probe manufactured by sharpening an optical fiber by anisotropic etching.

FIG. 7 shows a near-field probe manufactured by applying the near-field probe manufacturing method according to the present invention to an optical fiber probe. As shown in FIG. 7, the near-field probe 50 has a core 52 and a clad 54,
The core 52 has a sharpened portion, that is, a probe 54. The probe 54 is covered with a scatterer forming thin film 56,
The scatterer forming thin film 56 has a spherical scatterer 58 at a portion located at the tip of the probe. The scatterer 58 can be easily and reproducibly formed by irradiation with active light as described in the first embodiment or by contact with a heat supply source as described in the second embodiment. Can be formed.

Although several embodiments have been described in detail with reference to the drawings, the present invention is not limited to the above-described embodiments, but may be practiced without departing from the scope of the invention. Includes all implementations.

Therefore, the following can be said about the near-field probe of the present invention and the method for producing the same.

(1) A method for producing a probe used in a near-field microscope or a near-field optical recording apparatus, wherein a step of coating the tip and side surfaces of the probe with a substance containing silver oxide, and a step of applying the coated probe Forming a scatterer by causing a chemical reaction at the tip of the probe. (2) A probe used in a near-field microscope or a near-field optical recording device, A near-field probe, wherein the tip and side surfaces of the near field probe are coated with a substance containing silver oxide, and the coating has a scatterer formed by irradiating active light at the tip portion.

(3) A probe used in a near-field microscope or a near-field optical recording device, wherein the tip and side surfaces of the probe are coated with a substance containing silver oxide, and the coating is provided at the tip with a heat supply source. A near-field probe having a scatterer formed by a chemical reaction upon contact.

(4) A probe used in a near-field microscope or a near-field optical recording device, wherein a film in which silver oxide is sandwiched between dielectrics is formed on the tip and side surfaces of the probe. probe.

(5) A method for producing a probe used in a near-field microscope or a near-field optical recording device, wherein a step of coating the tip and side surfaces of the probe with a substance containing silver oxide; Forming a scatterer by irradiating the tip of the substrate with active light.

(6) A method for producing a probe used in a near-field microscope or a near-field optical recording device, wherein a step of coating the tip and side surfaces of the probe with a substance containing silver oxide; Forming a scatterer by bringing a tip of the scatterer into contact with a heat supply source.

(7) A method for producing a probe used in a near-field microscope or a near-field optical recording device, the method including a step of forming a film in which silver oxide is sandwiched between a tip and side surfaces of the probe by a dielectric. A method for producing a near-field probe.

[0045]

According to the present invention, there is provided a scattering probe which generates little background light. Also provided is a method for easily producing such a probe with good reproducibility.

[Brief description of the drawings]

FIG. 1 is a schematic side sectional view of a near-field probe according to a first embodiment of the present invention.

FIG. 2 is a diagram for explaining a method for manufacturing a near-field probe according to the first embodiment of the present invention.

FIG. 3 is a diagram showing a relationship between an intensity distribution of active light and a scatterer formed.

4A is a transmission image of a substrate on which a scatterer forming thin film is formed before irradiation with active light, and FIG. 4B is a transmission image after irradiation of active light.

FIG. 5 shows a modification of the method for manufacturing a near-field probe according to the first embodiment of the present invention.

FIG. 6 is a diagram for explaining a method for manufacturing a near-field probe according to the second embodiment of the present invention.

FIG. 7 is a schematic sectional side view of a near-field probe manufactured by applying the near-field probe manufacturing method according to the present invention to an optical fiber probe.

[Explanation of symbols]

 Reference Signs List 10 near-field probe 16 probe 24 scatterer forming thin film 26 scatterer

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Junji Tominaga 1-1-4 Higashi, Tsukuba, Ibaraki Pref., National Institute of Advanced Industrial Science and Technology (72) Inventor Takashi Nakano 1-1-4 Higashi, Tsukuba, Ibaraki Pref. Institute of Industrial Science and Technology (72) Inventor Nobushi Ashita 1-1-4 Higashi, Tsukuba, Ibaraki Prefecture Institute of Industrial Science and Technology (72) Inventor Hiroshi Fuji 22 Nagaike-cho, Abeno-ku, Osaka-shi, Osaka No. 22 Inside Sharp Co., Ltd. (72) Inventor Yoshimasa Suzuki 2-43-2 Hatagaya, Shibuya-ku, Tokyo F-term in Olympus Optical Industry Co., Ltd. 2F065 AA25 AA49 DD04 FF01 PP24 UU07

Claims (3)

[Claims] 1. A probe used in a near-field microscope or a near-field optical recording device, wherein a tip and a side surface of the probe are coated with a substance exhibiting a thermal non-linear response. A near-field probe having a scatterer formed by thermally causing a chemical reaction. 2. A probe used in a near-field microscope or a near-field optical recording device, wherein the tip and side surfaces of the probe are coated with a substance containing silver oxide, and the coating is thermally chemically treated at the tip. A near-field probe having a scatterer formed by causing a reaction. 3. A method of manufacturing a probe used in a near-field microscope or a near-field optical recording apparatus, comprising: coating a tip and side surfaces of the probe with a substance having a thermally non-linear response; A step of forming a scatterer by causing a chemical reaction at the tip of the probe thus obtained.