JP6219257B2 - Near-field measurement method and near-field optical microscope - Google Patents

Description

  The present invention relates to a near-field measurement method and a near-field optical microscope, and more particularly to improvement of a probe position control system.

A general optical microscope can observe a non-contact, non-destructive and minute part with respect to a measurement object. Furthermore, since a component to be measured can be analyzed by using a spectroscopic analyzer or the like together, an optical microscope is applied in various fields.
However, a general optical microscope cannot observe an object with a resolution smaller than the wavelength of light.

On the other hand, although the electron microscope can greatly improve the resolution compared with the above-mentioned optical microscope, if the atmosphere or solvent exists in the optical path of the electron beam, electrons are scattered by those media, and the observation accuracy is extremely high. Go down.
For this reason, the electron microscope is not always capable of observing with satisfactory accuracy, particularly in the field of handling biological samples.

In recent years, near-field optical microscopes based on principles different from those of optical microscopes and electron microscopes have been developed and their applications are expected. Therefore, a near-field optical microscope will be described.
First, near-field light refers to the direction from the target to the inside of the target when light is irradiated on the surface of the target under conditions of total reflection or when light is irradiated to a target having a diameter smaller than the wavelength of the light. Or, it is a general term for the field of light (energy) that oozes out from the object toward the outside of the object.
The near-field optical microscope collects the light generated as a result of the interaction between the near-field light and the sample measurement surface as detection light, and quantitatively analyzes the detection light to finely measure the surface of the object to be measured. Allows composition evaluation.

Here, the probe used in the near-field optical microscope is divided into two types, an aperture type and a scattering type.
The former uses an optical fiber having a minute opening at the tip as a probe, and the latter uses a metal needle with a sharpened tip as a probe.
In particular, in the field of development of near-field optical microscopes in recent years, improvement of the apparatus using the former aperture type probe is frequently performed.

As a typical technique for forming a minute opening at the tip of the optical fiber, the minute opening 62 is covered (masked) with a metal film 64 as shown in FIG. Or a plurality of hydrofluoric acid buffer solutions 120 adjusted so that the dissolution rate of the core part 112 is different from that of the clad part 114 as shown in FIG. It is known to immerse the portion 112 step by step, create a three-step tapered sharpened portion 116, and use the sharpened portion for a minute opening.
Then, by appropriately using the techniques described in Patent Documents 1 and 2, a minute aperture having a diameter (several tens to hundreds of nanometers) shorter than the wavelength of the excitation light is formed at the tip of the optical fiber. And the optical fiber is used for the near-field probe.

On the other hand, three methods of an illumination-collection mode, an illumination mode, and a collection mode are known for near-field measurement using the probe having the minute aperture.
In the illumination-collection mode, first, excitation light is introduced into a minute aperture, thereby generating near-field light having a magnitude similar to the wavelength of the excitation light in the vicinity of the minute aperture.
Next, the sample measurement surface is brought close to the vicinity of the near-field light, and light scattered by the sample measurement surface is generated when the distance between the near-field light and the sample measurement surface is close to several tens of nanometers. .
After that, the scattered light is collected as detection light, collected through the probe's micro-aperture, and physical changes in the light, such as how much wavelength the collected detection light is shifted with respect to the excitation light, are analyzed. By doing so, the composition of the sample surface can be clarified.

In the illumination mode, near-field light is generated in the vicinity of the sample measurement surface by irradiating the above-described excitation light to the sample measurement surface (at an angle satisfying the condition of total reflection).
When the microscopic aperture of the probe is brought close to the near-field light and the distance between the near-field light and the microscopic aperture approaches several tens of nanometers, a part of the near-field light scattered by the microscopic aperture is The light passes through the optical fiber through the minute aperture.
In this illumination mode, the scattered light transmitted through the optical fiber is condensed as detection light.

In the collection mode, similar to the illumination-collection mode, the near-field light and the sample measurement surface are brought closer to each other while the near-field light is generated in the vicinity of the minute aperture of the probe.
As a result, when the distance between the near-field light and the microscopic aperture is close to several tens of nanometers, a part of the light scattered by the sample measurement surface is transmitted through the sample through the sample measurement surface. Become.
In this collection mode, the scattered light transmitted through the sample is collected as detection light.

  The above is a near-field measurement method using an aperture-type probe. With a near-field optical microscope, the amount of physical change is analyzed between detection light and excitation light obtained by these various measurement methods. Thus, it is possible to evaluate a fine composition on the surface of the measurement sample.

Here, in the conventional near-field probe, it has been a mainstream to use a long optical fiber as shown in FIG. 2 of the above-mentioned Patent Document 1, but the present inventors use a short optical fiber. As a result, it has been found that the accuracy of near-field measurement can be improved, and the invention is known as Patent Document 3.
The greatest feature of Patent Document 3 is that a short probe 14 having a length of 7 mm in the longitudinal direction (see FIG. 2 of Patent Document 3) is employed. By using the short probe 14, the energy of the light to be measured is measured. This makes it possible to prevent loss and mix noise.
Further, in FIG. 3 of Patent Document 3, by adopting the probe switching means 42, the short probe 14 is inserted into the optical path from the objective lens 16 to the sample 32, and the short probe 14 is retracted from the optical path. Can do.
That is, by using the probe switching means 42, it is possible to perform both the microscopic measurement and the near-field measurement with a single microscope apparatus.

JP 2003-106978 A JP 2003-4623 A JP 2009-63410 A

However, the inventors of the present invention have repeatedly implemented the invention of Patent Document 3 above, and the image of the measurement region obtained by the near-field measurement is compared with the region scheduled for near-field measurement set on the sample measurement surface. It has been found that there may be a deviation of up to several hundred nanometers.
The resolution of the near-field optical microscope is on the order of several nanometers at the maximum, and the deviation between the planned measurement area and the actual measurement area is not allowed in the near-field measurement, and is promptly Development of technology to solve this problem has been demanded.

  Therefore, the present invention has been made in view of the above-mentioned problems of the prior art, and its purpose is to prevent a positional shift that may occur between the near-field measurement scheduled area and the near-field measurement area, and to prevent proximity at the correct position. An object of the present invention is to provide a near-field measurement method that enables field measurement, and a near-field optical microscope for performing the near-field measurement method.

In order to solve the above problems, the present invention
A near-field measurement scheduled region set on the sample measurement surface using a near-field probe comprising an optical fiber having a length that can be inserted into a space from the objective lens to the focal point of the objective lens so that the optical axes coincide. the when run査, according to the mounting direction of the optical fibers in the probe, that the position of the near-field measurement with respect to the near-field measuring scheduled region is shifted, the near-field measuring method for prevent (S10),
Inserting the near-field probe into the optical axis of the objective lens (S12);
Aligning the center of the upper end of the optical fiber with the focal point of the objective lens (S14);
Moving the probe in a directly upward direction and aligning the focus of the objective lens at the height position of the lower end of the optical fiber (S16);
A step of determining the center position of the lower end of the optical fiber on the microscopic measurement image in a state where the focus of the objective lens is aligned with the height position of the lower end of the optical fiber, and adding a mark to the center position (S18). When,
A step (S20) of calculating a deviation amount between the focal point of the objective lens and the position of the mark, depending on how to attach the optical fiber in the near-field probe, from the center of the upper end of the optical fiber to the center of the lower end of the optical fiber. It is characterized in that the amount of displacement is obtained under microscopic measurement.

Furthermore, in the near field measurement method,
Moving the optical fiber in the upward direction, and aligning the specific position of the near-field measurement scheduled region to the position of the mark through the optical fiber based on the amount of deviation (S22);
The optical fiber and the sample measurement surface are respectively moved in the downward direction, the center of the upper end of the optical fiber is aligned with the focal point of the objective lens, and the near-field measurement scheduled region is specified at the center of the lower end of the optical fiber. A step of aligning the position (S24),
By starting near-field measurement in a state where the center of the lower end of the optical fiber is aligned with a specific position of the near-field measurement scheduled region, it is possible to prevent a deviation of the near-field measurement position depending on how to attach the optical fiber. Features.
It is preferable that the specific position of the near-field measurement scheduled area is a measurement start position of the near-field measurement scheduled area.

In addition, a near-field measurement set on a sample measurement surface using a near-field probe comprising an optical fiber having a length that can be inserted into a space from the objective lens to the focal point of the objective lens so that the optical axes coincide with each other. when査run the scheduled region, according to the mounting direction of the optical fibers in the probe, that the position of the near-field measurement with respect to the near-field measurement plan area is shifted, a near-field optical microscope 200 obviate,
A visible light source (60) that emits visible light during microscopic measurement;
An excitation light source (70) for emitting excitation light for generating near-field light during the near-field measurement;
An objective lens (80) for condensing the light emitted from each of the light sources toward the target object from above the target object during the microscopic measurement and the near-field measurement;
A stage (30) on which a measurement sample (20) is placed;
Stage position adjusting means (40) for adjusting the position of the measurement sample (20);
A near-field probe (10) inserted between the objective lens (80) and the measurement sample (20);
An arm (50) supporting the near-field probe;
Wherein upon microscopic measurement, the pair reflected by elephant product and visible light detector for detecting the light condensed by the objective lens (90),
Spectral detection means (100) for spectrally detecting light collected by the objective lens among light generated by interaction between the surface of the measurement sample and near-field light during the near-field measurement;
Analysis means (110) for analyzing various optical information detected by the visible light detection means and the spectral detection means;
Microscopic measurement image is analyzed by the analyzing means, and a near-field measurement image, a monitor (120) to be displayed respectively,
A light guide means (130) for switching an optical path from each light source to a detection means corresponding to the light source according to each measurement,
The near-field probe (10) has an optical fiber (12) and a thin rod (14);
The object is the measurement sample (20) and the optical fiber (12),
The analysis means (110) moves the optical fiber in the vertical direction by the arm (50) in a state where the microscopic measurement image is displayed on the monitor (120), and the center of the optical fiber from the center of the upper end to the center of the lower end. It is characterized in that the amount of deviation leading to is calculated.

Further, the analyzing means (110) uses the stage position adjusting means (40) based on the deviation amount to align the specific position of the near-field measurement scheduled region with the center of the lower end of the optical fiber,
By shifting to near-field measurement in this state, the position of near-field measurement is prevented from being shifted depending on how the optical fiber is attached.
The arm (50) includes a probe support end (52) that supports the near-field probe (10);
A near-field probe position adjusting unit (56) for adjusting a relative positional relationship between the near-field probe and the objective lens;
An objective lens joint end (54) having a shape of a threaded portion of the objective lens or a shape adapted to a side peripheral surface of the objective lens;
It has.

The length of the optical fiber (12) in the longitudinal direction is not more than half of the focal length of the objective lens (80),
The measurement sample can be microscopically observed through the near-field probe (10) by moving the near-field probe (10) in the upward direction.

In the near-field optical microscope of the present invention, the position of the measurement sample is adjusted by the stage position adjusting means, and the position of the near-field probe is adjusted by the arm. Thereby, during the microscopic measurement, the measurement sample and the near-field probe can be moved independently.
In the near-field measurement method of the present invention, in the microscopic measurement, the deviation amount from the center of the upper end of the optical fiber to the center of the lower end according to the inclination of the optical fiber is obtained based on the focal point of the objective lens. In order to obtain the amount of deviation, a step of adding a mark to the center position of the lower end of the optical fiber has been defined. However, it is only necessary to calculate the amount of deviation between the focal position of the lens and the center position of the lower end of the optical fiber in a later step. Therefore, in the step of adding this mark, the analysis means recognizes the position of the center of the lower end of the optical fiber.
As a result, even if the optical fiber is attached to the near-field probe with a tilt that cannot be confirmed by human visual observation, the center of the lower end of the optical fiber (that is, the minute aperture) is based on the amount of deviation. The specific position or the measurement start position of the near-field measurement scheduled area can be matched.
With the above configuration, the present invention can perform near-field measurement at the correct position without being affected by the inclination of the optical fiber with respect to the near-field probe.

It is a figure which shows the positional relationship of each component of the near-field optical microscope of this invention. It is a figure which shows the structure of the near field probe attached to the said near field optical microscope. It is a figure which shows the mode of the microscopic measurement using the near field optical microscope of this invention. It is a flowchart which shows the near field measurement method of this invention. It is a figure which shows the detail of the near field measuring method of this invention using a near field optical microscope. It is a flowchart which shows the modification of the near field measuring method of this invention.

Hereinafter, as a description of a preferred embodiment of the present invention, a near-field optical microscope 200 capable of performing near-field measurement in an illumination-collection mode will be described with reference to FIGS. 1 and 2.
Embodiment FIG. 1 is a diagram showing each configuration of a near-field optical microscope 200 of the present invention, which supports a near-field probe 10, a measurement sample 20, a stage 30, a stage position adjusting means 40, and a near-field probe. Arm 50, visible light source 60, excitation light source 70, objective lens 80, visible light detection means 90, spectral detection means 100, analysis means 110, monitor 120, and light guide means 130 are provided. Yes.

Here, the near-field probe 10 includes an optical fiber 12 and a thin rod 14 as shown in FIG. 2A, and the optical fiber 12 is attached to the tip of the thin rod 14.
The optical fiber 12 shown in FIG. 2A has an upper end surface 12a, a lower end surface 12b, a conical protrusion 12c located substantially at the center of the lower end surface 12b, and a minute opening formed at the tip of the conical protrusion 12c. 12d.
Further, as shown in the figure, the minute aperture 12d having a diameter of 100 n m, as in the Patent Document 1, are formed by a method for masking the core portion of a metal film.

The length of the optical fiber 12 in the longitudinal direction is preferably shorter than the focal length of the objective lens 80. In particular, the length of the optical fiber 12 in the longitudinal direction is preferably half or less of the focal length. More specifically, the length of the optical fiber 12 in the longitudinal direction is 2 mm or less.
The diameter of the upper end surface 12a of the optical fiber 12 shown in FIG. 2 (B) is a thin rod facing in the direction perpendicular to both the longitudinal direction of the optical fiber 12 and the longitudinal direction of the thin rod 14 (that is, the Y-axis direction in the figure). It is preferable that the distance is shorter than the distance between the two side surfaces.
By using the optical fiber having the above characteristics, the focal point of the objective lens can be aligned with the upper end surface 12a or the lower end surface 12b of the optical fiber 12, respectively. It is also possible to observe an object through the optical fiber.

After the measurement sample 20 is placed on the stage 30, the relative positional relationship between the measurement sample 20 and the objective lens 80 is adjusted by the stage position adjusting means 40.
The arm 50 has an objective lens joint end that matches the near-field probe support end 52 that supports the near-field probe 10 and the shape of the screw portion 82 of the objective lens 80 or the shape of the side peripheral surface 84 of the objective lens. 54, and a near-field probe position adjustment unit 56 that adjusts the relative positional relationship between the near-field probe 10 and the objective lens 80.

  Here, a mechanism for supporting the near-field probe 10 in a slide format is adopted for the near-field probe support end 52. Thereby, the near-field probe 10 can be easily supported and removed. In addition to the above-mentioned slide type, the probe support end 52 can be appropriately used one that sandwiches and supports the probe between two opposing plates, or one that uses magnetic force.

  In addition, since the objective lens of a general microscope is standardized in the shape of the side peripheral surface, the lens radius, and the like, the objective lens joint end portion 54 is adapted to the shape of the side peripheral surface of the lens to be used. The arm 50 can be attached to various objective lenses simply by adjusting the shape of the joint end.

The near-field probe position adjusting unit 56 includes a part that adjusts the position of the near-field probe 10 in the X-axis direction and a part that adjusts the position in the Z-axis direction. It is adjustable in two dimensions.
In the field of microscope development, attaching an adjustment mechanism in the Y-axis direction to the Z-axis direction adjustment part or attaching an adjustment mechanism in the Y-axis direction to the X-axis direction adjustment part is a technique that can be appropriately performed. is there.

The visible light source 60 emits visible light toward the objective lens 80 during microscopic measurement.
The excitation light source 70 emits excitation light toward the objective lens 80 during near-field measurement.
The objective lens 80 condenses the light emitted from the visible light source 50 on the measurement surface of the measurement sample 20 when microscopically measuring the measurement surface of the measurement sample 20 (see FIG. 3). When performing near-field measurement, the objective lens 80 condenses the light emitted from the excitation light source 70 on the upper end surface 12a of the optical fiber. Thereby, near-field light can be generated in the vicinity of the minute opening 12d.

The visible light detecting means 90 is composed of an imaging element for visible observation provided in a general visible optical microscope.
The spectroscopic information detection means 100 is for spectrally detecting light (detection light) scattered from the measurement sample during near-field measurement. The spectroscopic information detection means 100 is for spectroscopes such as a prism and an array type detector. Image sensor.
Each optical information obtained by using the visible light detecting means 90 or the spectral information detecting means 100 is transmitted to the analyzing means 110.

The analysis unit 110 performs processing of information regarding microscopic measurement and processing of information regarding near-field measurement based on the optical information, and the analysis unit 110 transmits a result of the information processing to the monitor 120. The processing result is displayed on the monitor 120.
Then, the user sets a near-field measurement scheduled area on the measurement sample 20 based on the information processing result displayed on the monitor screen.

During near-field measurement, the distance between the near-field probe 10 and the measurement sample 20 needs to be as short as several nanometers at the shortest. Therefore, the analysis unit 110 includes the near-field probe 10 and the measurement sample 20. It is also important to monitor the position information between the two.
That is, based on the position monitoring information, the analysis unit 110 is set so that the position adjustment signal is transmitted to the stage position adjustment unit 40. In particular, it is preferable to cause the analysis unit 110 to monitor the position so as to maintain a predetermined distance between the near-field probe 10 and the measurement sample 20.
The light guide means 130 shown in FIG. 1 is for switching the optical path in accordance with the measurement. By using the light guide means 130, a single near-field optical microscope 200 can perform microscopic measurement. And near-field measurement.

The near-field optical microscope 200 of the present invention is configured as described above, and the operation of the near-field optical microscope 200 will be described below.
<Microscopic measurement (S0)>
In the near-field optical microscope 200 of the present invention, the microscopic measurement (S0) is performed as shown in FIG. That is, the visible light emitted from the visible light source 60 is guided to the objective lens 80 using the light guide unit 130, and then the objective lens 80 condenses the visible light on the surface of the measurement sample 20.
Thereafter, a part of the light reflected by the surface of the measurement sample 20 is collected by the objective lens 80, and the collected light is guided to the visible light detection unit 90 by the light guide unit 130.

Thereafter, the visible optical information obtained by the visible light detection means 90 is transmitted to the analysis means 110 and then converted into a microscopic measurement image by the analysis means 110. The converted microscopic measurement image is displayed on the monitor 120, and the user sets a near-field measurement scheduled area based on the microscopic measurement image on the monitor.
During this microscopic measurement (S0), the near-field probe 10 may be retracted from the optical path of the objective lens 80 using various methods. For example, as shown in FIG. Using the axial adjustment portion, the near-field probe 10 can be retracted from its optical path.

Subsequently, after the near field measurement scheduled region is set by the user, the near field measurement (S30) in the illumination-collection mode shown below is performed.
<Near field measurement (S30)>
In the near field measurement (S30), the light guide means 130 is used to switch from the optical path shown in FIG. 3 to the optical path shown in FIG. Start by aligning the 80 focal points. That is, the excitation light emitted from the excitation light source 70 is condensed on the upper end surface 12a of the optical fiber 12, so that near-field light is generated from the vicinity of the minute aperture 12d.

Thereafter, using the stage position adjusting means 40, the measurement sample 20 is moved so that the near-field measurement start position is aligned with the minute opening 12d.
At this time, the measurement sample 20 is gradually brought closer to the minute opening 12d. When the distance between the measurement sample 20 approaches the minute opening 12d to several tens of nanometers, the near-field light near the minute opening 12d The surface of the measurement sample 20 interacts, and a part of the near-field light is scattered by the surface of the measurement sample 20.

Detection is performed by guiding a part of the light (detection light) scattered by the surface of the measurement sample 20 to the spectroscopic detection unit 100 using the minute aperture 12d, the objective lens 80, and the light guide unit 130. The optical information of the light is acquired, and then the optical information is transmitted from the spectroscopic detection means 100 to the analysis means 110.
In the analysis unit 110, for example, the wavelength shift amount of the detection light with respect to the wavelength of the excitation light is analyzed, and the composition of the measurement sample 20 at the near-field light measurement start position is determined.
Similarly, the stage position adjusting means 40 is used to evaluate the composition at all measurement positions on the near-field measurement planned area, and the near-field measurement results are displayed on the monitor 120. The measurement (S30) ends.

As described above, it has been described that as a function and effect of the near-field optical microscope 200 of the present invention, general microscopic measurement (S0) and near-field measurement (S30) can be performed with a single microscope.
Here, conventionally, the near-field probe 10 is kept in that state without adjusting each part of the microscope apparatus with respect to the near-field measurement scheduled region set by using the result of the microscope measurement (S0). The used near field measurement (S30) was performed.
However, the measurement sample surface image obtained as a result of actual near-field measurement (S30) may deviate by several hundred nm at the maximum from the near-field measurement scheduled region, and the present inventors correct the deviation. We developed a near-field measurement method (S10).
Details of the near-field measurement method (S10) of the present invention will be described below with reference to FIGS.

<Near field measurement method (S10)>
First, as shown in FIG. 4, the near-field measurement method (S10) of this embodiment includes a step (S12) of inserting a near-field probe into the optical axis of the objective lens, and the center of the upper end of the optical fiber at the focal point of the objective lens. , The step of aligning the focus of the objective lens to the height position of the lower end of the optical fiber (S16), and the center of the lower end of the optical fiber on the microscopic measurement image The step of determining the position of the center and adding a mark to the center position (S18), the step of calculating the amount of deviation between the focal point of the objective lens and the position of the mark (S20), and using the amount of deviation, A step of aligning the specific position of the near-field measurement planned area with the position (S22), aligning the center of the upper end of the optical fiber with the focal point of the objective lens, and specifying the near-field measurement planned area at the center of the lower end of the optical fiber It includes a step (S24) for aligning the location, the.

Then, after correcting the shift amount according to the inclination of the optical fiber, the step of switching the light source and the optical path of the microscope apparatus from the microscopic measurement to the near-field measurement (S26) is performed, thereby performing the microscopic measurement (S30). Preparations are made for After the various preparations are completed, the above-mentioned near-field measurement (S30) is performed by the microscope 200.
That is, the near-field measurement method (S10) includes the calculation part of the deviation amount according to the inclination of the optical fiber, which leads to the steps (S12) to (S20), and the deviation amount that leads to the steps (S22) to (S24). In particular, the calculation part of the deviation amount according to the inclination of the optical fiber leading to the steps (S12) to (S20) is important.

5A to 5H show the operation of each member and the adjustment of the position of each member in the above steps (S12) to (S26). The microscopic measurement images in 5 (A) to (H) are sequentially displayed.
FIG. 5A shows the stage where the near field measurement scheduled area is determined using the result of the microscopic measurement (S0). After the scheduled area is determined, the stage position adjusting means 40 is used. Then, the sample 30 is retracted in the downward direction, and the near-field measurement method (S10) is started from this state.

  In the step (S12) shown in FIGS. 5A to 5B, the near-field probe 10 is inserted on the optical axis of the objective lens 80 (in the optical path). Here, by making the X-axis direction of the objective lens 80 coincide with the sliding direction of the near-field probe 10, the optical fiber 12 can be easily inserted into the optical path of the objective lens 14.

  Thereafter, in the step (S14) shown in FIGS. 5B to 5C, only the Z-axis direction adjustment portion of the probe position adjusting means 56 is used, and the near-field probe 10 inserted on the optical path is moved in the direct downward direction. The center of the upper end surface 12a of the optical fiber is aligned with the focal point of the objective lens 80 (microscopic measurement image in FIG. 5C).

Subsequently, in the step (S16) shown in FIGS. 5C to 5D, the near-field probe 10 is moved directly downward using only the Z-direction adjusting portion of the probe position adjusting means 56, and the lower end surface of the optical fiber. The focus of the objective lens 80 is aligned with the height position of 12b (microscopic measurement image in FIG. 5D).
Thereafter, in the step (S18) shown in FIG. 5E, the analyzing means 110 recognizes the lower end surface 12b of the optical fiber and adds a mark to the center of the lower end surface 12b of the optical fiber. In step (S20), the analysis means 24 calculates the distance between the mark and the focal point of the objective lens 14, that is, the amount of deviation.
Thereby, the inclination amount of the optical fiber 12 with respect to the near-field probe 10 becomes clear. The subsequent steps are correction steps for actually performing accurate near-field measurement using the deviation amount.

That is, in the step (S22) shown in FIGS. 5E to 5G, the stage position adjusting means 40 is appropriately operated based on the amount of deviation, and the specific position of the measurement sample 20 at the center of the mark in the microscopic image. To match. At this time, by moving the near-field probe 10 in a direction immediately above to a position where no image is formed in the microscopic image, the measurement sample 20 can be identified at the center of the mark even though the near-field probe 10 is passed. The position can be accurately aligned (microscopic measurement image in FIG. 5G).
In the step (S24) shown in FIGS. 5G to 5H, the near-field probe 10 and the measurement sample 20 are moved in the direct downward direction, and the center of the upper end surface 12a of the optical fiber is aligned with the focal point of the objective lens 80. And the specific position of the near field measurement plan area is aligned with the center of the lower end surface 12b of the optical fiber.

  And after a process (S24) is complete | finished, a process (S26) is started and a light source and an optical path are switched. Thereafter, the near-field measurement (S30) described above is started, and the stage position adjusting means 40 is used to bring the measurement start position of the near-field measurement planned area close to the microscopic aperture 12d of the optical fiber as shown in FIG. Then, the composition evaluation at the measurement start position starts.

As described above, in steps (S12) to (S20) of the near-field measurement method (S10) of the present invention, the shift amount corresponding to the inclination of the optical fiber 12 with respect to the focal point of the objective lens 80 is calculated, and the lower end 12b of the optical fiber 12 is calculated. The position of the minute opening 12d is accurately determined.
In the subsequent steps (S22) to (S24), the specific position on the measurement sample 20 and the position of the minute opening 12d are aligned with high accuracy, and the inclination of the optical fiber is corrected using the shift amount.
In step (S26), preparations are made for near-field measurement.
As described above, the near-field measurement method (S10) of the present invention appropriately captures and corrects the inclination of the optical fiber 12 even if the optical fiber 12 is attached with an inclination that cannot be confirmed by human eyes. can do.

In the near-field measurement method (S10) of the present embodiment described above, the specific position of the near-field measurement scheduled area is aligned with the center position (the minute opening 12d) of the lower end of the optical fiber 12b. As described above, the measurement start position of the near-field measurement scheduled region can be set directly to the minute opening 12d.
When the measurement start position is set to be matched, in the step (S22), the measurement start position of the near field measurement scheduled region is aligned with the center of the mark, and in the step (S24), the near field measurement scheduled region is set. The measurement start position is aligned.

  That is, in another embodiment of the present invention, since the measurement start position of the near-field measurement scheduled region is aligned with the minute opening 12c of the optical fiber 12, the near-field measurement can be started as it is, and the start position from the specific position can be started. Moving to can be omitted.

<Modification>
Further, as a modification of the present invention, prior to the microscopic measurement (S0) of the measurement sample, the setting is changed so that the amount of deviation according to the inclination of the optical fiber leading to steps (12) to (20) is calculated. It is also possible to do. FIG. 6 is a flowchart schematically showing this case, and all steps corresponding to the above embodiment are indicated by reference numeral 100, and the description thereof is omitted.

That is, in the near-field measurement method (S110) of this modification, steps (S112) to (S120) are performed prior to the microscopic measurement (S100), and a deviation amount corresponding to the inclination of the optical fiber is calculated in advance. Decide the amount.
Thereafter, the near-field probe 10 is moved directly above the focal position of the objective lens 80, and microscopic measurement (S100) is performed through the near-field probe 10, whereby the surface of the measurement sample 20 is microscopically measured. Is displayed on the monitor 120. Thereafter, the near field measurement scheduled area is determined by the user through the monitor 120.

Then, using the determined amount of deviation, optical fiber tilt correction (steps S122 to S124) is performed, and the near-field is measured in a state where the minute opening 12d and the measurement start position of the near-field measurement are aligned with high accuracy. Measurement (S130) can be started.
As described above, by performing the calculation of the optical fiber displacement amount prior to the microscopic measurement on the sample surface as in this modification, for example, a quick and accurate near-field measurement can be performed on a sample with a high reaction speed. Is possible.

<About other near-field measurement methods>
In the embodiment of the present invention, the near-field optical microscope 200 adopting the illumination-collection mode has been described. However, the positions of the excitation light source 70 and the spectroscopic detection means 100 are not changed, and the illumination mode or the collection mode is used. By rearranging the light guide means 130 so as to correspond, a near-field optical microscope corresponding to each measurement method can be manufactured.
Further, in the present embodiment, the aperture type near-field probe 10 provided with an optical fiber at the tip has been described. However, even when the aperture type is replaced with the above-described scattering type near-field probe, the near-field measurement method of the present invention. By applying (S10), the displacement of the near-field measurement region can be prevented in advance.

<Addition of vibration means and shear force detection means>
The near-field optical microscope 200 of the present invention can be added with a vibrating means and a shear force detecting means. For example, vibration means is attached to the near-field probe support end 52, and the surface of the measurement sample 20 is brought close to the minute opening 12d while vibrating the optical fiber.
At this time, one side of the thin rod 14 is mirror-finished, and an optical lever type shear force detecting means for irradiating the side with a laser beam is used to change according to the distance between the minute opening 12d and the measurement sample 20. The vibration period and vibration amplitude of the optical fiber 12 are monitored at any time.
As a result, the near-field optical microscope 200 of the present invention can control the distance between the minute aperture 12d and the surface of the measurement sample 20 with high accuracy and constant, as in the conventional near-field optical microscope.
As the configuration of the shear force detection means, any device that can read the vibration period and vibration amplitude of the optical fiber 12 other than the above-mentioned optical lever type can be used. For example, a capacitance-type device that causes a change in the magnetic field according to the vibration and two piezoelectric elements are attached to the side of a thin rod so as to read the change, and the current state changes in these piezoelectric elements And the like.

  The present invention appropriately uses the objective lens and the near-field probe position adjusting means provided in the near-field optical microscope even when the optical fiber attached to the tip of the probe is tilted to such an extent that it cannot be visually confirmed. It is possible to correct the displacement of the optical fiber and prevent the displacement of the position that may occur between the near-field measurement scheduled region and the actual near-field measurement region.

200 Near-field optical microscope 60 Visible light source 10 Near-field probe 70 Excitation light source 12 Optical fiber 80 Objective lens 12a Optical fiber upper end surface 90 Visible light detection means 12b Optical fiber lower end surface 100 Spectral detection means 12c Conical protrusion 110 Analysis means 12d Optical fiber microscopic Opening 120 Monitor 14 Thin rod 130 Light guiding means 20 Measurement sample
30 stages
40 Stage position adjusting means
50 arms
52 Probe Support End 54 Objective Lens Joint End 56 Probe Position Adjustment Means S0 Microscopic Measurement
S10 Near field measurement method
S12 Step of inserting a near-field probe into the optical axis of the objective lens S14 Step of aligning the center of the upper end of the optical fiber with the focal point of the objective lens S16 Step of aligning the focus of the objective lens at the height of the lower end of the optical fiber S18 Optical fiber Step of determining the center position of the lower end and adding a mark to the center position of the lower end of the optical fiber S20 Step of calculating the amount of deviation between the focal point of the objective lens and the position of the mark S22 Measuring the near field at the position of the mark using the amount of deviation Step S24: Aligning the specific position of the planned area S24: Aligning the center of the upper end of the optical fiber with the focal point of the objective lens and aligning the specific position of the planned near-field measurement area with the center of the lower end of the optical fiber S30: Near-field measurement

Claims (7)

A near-field measurement scheduled region set on the sample measurement surface using a near-field probe comprising an optical fiber having a length that can be inserted into a space from the objective lens to the focal point of the objective lens so that the optical axes coincide. the when run査, according to the mounting direction of the optical fibers in the probe, that the position of the near-field measurement with respect to the near-field measuring scheduled region is shifted, the near-field measuring method obviate,
Inserting the near-field probe into the optical axis of the objective lens (S12);
Aligning the center of the upper end of the optical fiber with the focal point of the objective lens (S14);
Moving the probe in a directly upward direction and aligning the focus of the objective lens at the height position of the lower end of the optical fiber (S16);
A step of determining the center position of the lower end of the optical fiber on the microscopic measurement image in a state where the focus of the objective lens is aligned with the height position of the lower end of the optical fiber, and adding a mark to the center position (S18). When,
A step (S20) of calculating a deviation amount between the focal point of the objective lens and the position of the mark, depending on how to attach the optical fiber in the near-field probe, from the center of the upper end of the optical fiber to the center of the lower end of the optical fiber. A near-field measurement method, characterized in that the amount of displacement is obtained under microscopic measurement, The near-field measurement method according to claim 1,
Moving the optical fiber in the upward direction, and aligning the specific position of the near-field measurement scheduled region to the position of the mark through the optical fiber based on the amount of deviation (S22);
The optical fiber and the sample measurement surface are respectively moved in the downward direction, the center of the upper end of the optical fiber is aligned with the focal point of the objective lens, and the near-field measurement scheduled region is specified at the center of the lower end of the optical fiber. A step of aligning the position (S24),
By starting near-field measurement in a state where the center of the lower end of the optical fiber is aligned with a specific position of the near-field measurement scheduled region, it is possible to prevent a deviation of the near-field measurement position depending on how to attach the optical fiber. A characteristic near-field measurement method.   The near-field measurement method according to claim 2, wherein the specific position of the near-field measurement scheduled area is a measurement start position of the near-field measurement scheduled area. A near-field measurement scheduled region set on the sample measurement surface using a near-field probe comprising an optical fiber having a length that can be inserted into a space from the objective lens to the focal point of the objective lens so that the optical axes coincide. the when run査, according to the mounting direction of the optical fibers in the probe, that the position of the near-field measurement with respect to the near-field measurement plan area is shifted, a near-field optical microscope for prevent,
A visible light source that emits visible light during microscopic measurement;
An excitation light source that emits excitation light for generating near-field light during the near-field measurement;
An objective lens for condensing the light emitted from each light source toward the target object from above the target object during the microscopic measurement and near-field measurement;
A stage on which a measurement sample is placed;
Stage position adjusting means for adjusting the position of the measurement sample;
A near-field probe inserted between the objective lens and the measurement sample;
An arm supporting the near-field probe;
Wherein upon microscopic measurement, a visible light detector for detecting the light condensed by the reflected and the objective lens by Target material,
Spectral detection means for spectrally detecting the light collected by the objective lens among the light generated by the interaction between the surface of the measurement sample and the near-field light during the near-field measurement;
Analysis means for analyzing various optical information detected by the visible light detection means and the spectral detection means;
Microscopic measurement image is analyzed by the analyzing means, and a near-field measurement image, a monitor for displaying respectively,
Depending on the measurement, and a light guiding means for switching the optical path to the detecting means corresponding to the light source from the respective light sources,
The near-field probe has an optical fiber and a thin rod;
The object is the measurement sample and the optical fiber,
While displaying the microscopic measurement image on the monitor,
The analysis means uses the arm to move the optical fiber in the vertical direction, and calculates a deviation amount from the center of the upper end to the center of the lower end of the optical fiber. The near-field optical microscope according to claim 4,
Further, the analyzing means uses the stage position adjusting means based on the deviation amount to align the specific position of the near-field measurement scheduled area with the center of the lower end of the optical fiber, and shifts to near-field measurement in that state. Accordingly, the near-field optical microscope is characterized in that the position of near-field measurement is prevented from being shifted in accordance with how the optical fiber is attached. The near-field optical microscope according to claim 4 or 5,
The arm includes a probe support end for supporting the near-field probe;
A near-field probe position adjusting unit for adjusting a relative positional relationship between the near-field probe and the objective lens;
A near-field optical microscope comprising: a thread portion of the objective lens; or an objective lens joint end having a shape that fits a side peripheral surface of the objective lens. In the near-field optical microscope according to any one of claims 4 to 6,
The length in the longitudinal direction of the optical fiber is not more than half of the focal length of the objective lens,
A near-field optical microscope characterized in that the measurement sample can be microscopically observed through the near-field probe by moving the near-field probe in an upward direction.

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