JPH08136554A - Scanning stage means for scanning proximity field optical microscope - Google Patents

Abstract

PURPOSE: To obtain a scanning stage for scanning proximity field optical microscope in which the possibility of contamination with matching oil is eliminated. CONSTITUTION: A sample scanning means, i.e., a piezoelectric scanner 112, has an upper end secured with a stage supporting base 114 fixed with a stage 118 through a plurality of spacers 116. A prism 122 is disposed, while being supported by a supporting member 124, on the inside of a stage opening 120 with the upper face thereof being set slightly lower than that of the stage. The supporting member 124 passes through a space between the stage supporting base 114 and the stage 118 and it is supported without touching them. The gap is filled with a filler 126 over the entire circumference of the contact face between the prism 122 and the supporting member 124 and an oil sump 128 is formed of a groove on the outside thereof.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to scanning stage means for performing scanning in a scanning near field optical microscope.

[0002]

2. Description of the Related Art A scanning near-field optical microscope is a microscope that realizes an ultrahigh resolution of 0.1 μm or less, which exceeds the diffraction limit, which is the resolution limit of an optical microscope. This scanning near-field optical microscope is a type of scanning probe microscope typified by a scanning tunneling microscope, in which a mechanical probe is brought close to a sub-μm or less of the sample surface, and the sample and probe are scanned in XY or XYZ directions. Optical interaction between sample and probe tip (eg evanescent light)
Is a device for detecting, mapping and displaying on a monitor. An example of this device is disclosed, for example, in Japanese Patent Laid-Open No. 3-9170.
Is disclosed in.

Just as there are transmission type and epi-illumination type optical microscopes, there are several types of scanning near-field optical microscopes, which are called collection type, scattering type, emission type, and reflection type, respectively. ing.

The collection type scanning near-field microscope has a sample fixed to a prism or the like fixed to a scanning stage means for scanning the sample in the XY and Z directions, and the total reflection angle from the prism side to the fixed surface of the sample. After illuminating light at an angle of (critical angle) or more to localize the evanescent field near the sample surface and insert the tip of the probe into the evanescent field to form a propagating wave propagating in the probe, The propagating light is guided to the light detecting means and detected.

The scattering-type scanning near-field light microscope has almost the same structure as the collection-type scanning near-field light microscope, but a probe made of metal is used. In this device, by inserting a metal probe into the evanescent field localized near the sample surface, the evanescent light is scattered and made into propagating light, and the photodetection means includes a lens and an optical fiber arranged so that the probe can be peeked from the side. Is detected using.

The emission type scanning near-field light microscope also fixes the sample to a sample stage such as glass fixed to the scanning stage means for scanning the sample in the XY and Z directions, and the light emitted from the illumination means is fixed. The evanescent field created near the tip of the probe is brought close to the surface of the sample to make it a propagating light propagating in the sample, and then the propagating light is detected by using a photodetector arranged on the back side of the sample stage.

Further, the reflection type scanning near-field light microscope has almost the same structure as the emission type scanning near-field light microscope, but instead of arranging the light detecting means on the back side of the sample table, the probe is placed sideways. The lens and optical fiber are arranged so that you can look into it. Then, the light emitted from the illumination means detects the reflected light on the sample surface in the evanescent field generated near the tip of the probe.

The intensity of the evanescent field is exponentially attenuated with respect to the distance from the interface where the evanescent field is formed, and has a characteristic that it depends on the amount of illumination light. Therefore, in these scanning near-field light microscopes, in order to efficiently generate an evanescent field on the sample surface, it is necessary to perform optical matching between the sample and the sample stage, and the optical components such as the sample stage and the prism. In particular, the latter is one of the basic requirements required for a scanning near-field optical microscope. Generally, the optical matching between the sample stage and the prism is
This is done by filling matching oil between the sample stage and the prism so that air (refractive index is 1) does not exist between them, which prevents reflection at the interface. A glass plate (having a refractive index of about 1.5) is generally used as the sample stage, and a matching oil having a value between the refractive indices of the glass and the prism is selected.

Especially in a collection type or scattering type scanning near-field optical microscope, it is very important to obtain optical matching, and a matching oil is hung on a prism and a sample table on which a sample is placed is placed. By placing them, the two have an optical matching. This makes it possible to efficiently form an evanescent field on the sample surface. Further, by using this matching oil, light is not repeatedly reflected between the prism and the sample stage, which contributes to noise reduction.

Further, in the scanning type near-field optical microscope of the emission type or the reflection type, there is no one using the matching oil because the device configuration becomes complicated, but from the viewpoint of noise reduction, the sample stage and its proximity are not used. It goes without saying that it is preferable to perform some kind of optical matching with the optical components to be used.

On the other hand, in the scanning probe microscope, when observing a sample, it is first necessary to position the probe on a specific position of the sample to be measured. Japanese Patent Laid-Open No. 3-208246 discloses a mechanism for moving a sample stage on a piezoelectric scanner, which is a scanning stage means, to position a probe on a specific position of a sample. By applying a single sinusoidal voltage to the piezoelectric body scanner to move the piezoelectric body sharply in the X or Y direction and immediately stop it, the inertia of the sample table on the piezoelectric body scanner is used to obtain the piezoelectric body with μm accuracy. This is a mechanism for moving the position of the sample table on the scanner. Except for the piezoelectric scanner, it is not necessary to provide a monitor or gear for moving the sample table. If this mechanism is applied to a scanning probe microscope, the mechanical rigidity of the device can be maintained high and high resolution measurement is possible. You can

[0012] Japanese Patent Application No. 6-169597 proposes a scanner system applicable to a scanning near-field optical microscope. This is a scanner system that does not fix and hold the prism on the piezoelectric scanner that is the scanning stage means, but holds the prism at another place so that the movement of the piezoelectric scanner and the movement of the prism do not interlock. The principle of the positioning mechanism of Japanese Patent Laid-Open No. 3-208246 can be applied to the system, and positioning of the sample in the scanning near-field light microscope becomes easy.

The structure of this scanning stage means is shown in FIG. As shown, at the top of the tube scanner 1,
A stage base 6 having a U-shaped cross section is fixed, and a transparent stage 2 is mounted thereon. Stage table 6
Openings 6a and 6b are formed at opposite positions on both wall portions. A prism 64 is arranged in the cavity formed by the stage table 6 and the stage 2. Support members 67 are fixed to both sides of the prism 64, and the support members 67 are attached to the upper end of the base 5. As a result, the prism 64 is supported under the stage 2, and a matching oil for matching the refractive index is provided between the stage 2 and the prism 64. The sample 4 is placed on the stage 2, and the probe 7 is placed thereon. In addition, a light source 6 that emits light for generating an evanescent wave
0 is optically coupled via an optical fiber 61 to a lens 62 that transforms the light emitted therefrom into parallel light. The lens 62 is provided with an adjusting mechanism 63 that changes the emission angle of the parallel light.

The light emitted from the light source 60 propagates in the optical fiber 61, is emitted from the end face, and then the lens 6
2 becomes parallel light, enters the prism 64 through the opening 6a of the stage base 6, passes through the prism 64, the matching oil 68, and the stage 2, and enters the lower interface of the sample 4 at an incident angle of a critical angle or more. Incident. As a result, sample 4
An evanescent wave appears near the upper surface of the. The light reflected on the lower interface of the sample 4 is emitted to the outside through the opening 6b of the stage table 6. The probe 7a is scanned along the sample surface in the area where the evanescent wave exists. As a result, scattered light having an intensity corresponding to the distance between the tip of the probe 7a and the surface of the sample 4 is generated. Probe 7
It propagates in a and is detected by using a photoelectric conversion element or the like.

In this structure, the prism 64 is fixed to the base 5, and the stage 4 and the stage 2 are moved by the tube scanner 1 in addition to the sample 4 during scanning. The total weight of the stage base 6 and the stage 2 is lighter than the weight of the prism 64, and therefore the resonance frequency is high. As a result, the scanning speed is improved, and the influence of external vibration is reduced. As a result, a high-resolution scanning near-field light microscope can be realized.

[0016]

DISCLOSURE OF THE INVENTION For example, in a collection type scanning near-field microscope, when the matching oil is hung on a prism and the glass serving as a sample stand is placed on the prism, the matching oil hung up until now is Due to the small amount, no special consideration was given to the processing of matching oil.When dropping new matching oil, such as when changing the sample table, use old lens cleaning paper to clean the old matching oil. This matching oil was treated by wiping it off and dropping new matching oil.

However, in such a method, it is inevitable that the matching oil wraps around and adheres to the surface other than the surface of the prism on the sample table side, and the periphery of the piezoelectric scanner as the scanning stage means is covered with the matching oil. It often gets dirty. The contamination by the matching oil not only makes the apparatus dirty, but also causes the matching oil attached to the surface other than the surface of the prism on the sample stage side to disturb the illumination light, which is not preferable in terms of measurement. In particular, when the illumination light is incident at an angle very close to the angle (critical angle) at which the total reflection on the sample side of the prism is made, the illumination light is generated by the matching oil on the surface other than the sample table side of the prism. May be deflected, and a part of the illumination light may have a component that escapes to the sample side without causing total reflection on the sample side surface of the prism. Such a phenomenon is
The collection type scanning near-field light microscope detects light other than evanescent light, and the resolution is extremely deteriorated.

Further, in the scanning stage means for the scanning near-field light microscope disclosed in Japanese Patent Application No. 6-169597, even when the matching oil is put between the prism and the sample stage, the surface energy of the matching oil is high. In order to overcome the above problem and allow the sample stage to move by inertial force, it is necessary to make the distance between the prism and the sample stage wide to some extent. This is because if the space is too narrow, the two will be attracted to each other by the matching oil and the sample stage will not move. However, if the gap is made wider, the amount of matching oil put in between will inevitably increase, and when the sample, that is, the sample table is replaced, the matching oil spills onto the surface of the prism other than the sample table side and adheres. The problem to do becomes more serious.

An object of the present invention is to provide a scanning stage means for a scanning near-field optical microscope in which the matching oil does not contaminate optical parts such as prisms located under the sample.

[0020]

A scanning stage means for a scanning near-field light microscope according to the present invention includes a sample stage for mounting a sample, a stage on which the sample stage is mounted, an actuator for moving the stage, and matching. An optical member that is optically coupled to the sample stage via oil, a support member that supports the optical member independently of the stage, and a means for collecting matching oil that is provided around the optical member are provided. . The means for collecting the matching oil is, for example, a groove formed in the support member so as to surround the optical member.

[0021]

The optical member such as the prism is supported by the supporting member such that the upper surface thereof is slightly lower than that of the stage. When mounting the sample table on the stage, first, a predetermined amount of matching oil is dropped on the optical member, and then the sample table is mounted on the stage. As a result, the gap between the upper surface of the optical member and the lower surface of the sample table is filled with matching oil without entering air, and the refractive indexes of the two are matched.

When the sample table is removed, the matching oil spilled from the upper surface of the optical member flows down into the groove formed around it and collects there. It is more preferable to provide a seal member at the joint between the optical member and the support member so that the matching oil does not soak into the joint. After removing the sample table, the matching oil remaining on the upper surface of the optical member and the matching oil spilled into the groove are
Absorb and remove with absorbent paper or lens cleaning paper.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A scanning stage means of a scanning near-field light microscope which is an embodiment of the present invention will be described below with reference to FIGS. As shown in FIG. 1, a stage support 114 is fixed to the upper end of a piezoelectric scanner 112 which is a means for scanning a sample in XY directions. A stage 118 is provided above the stage support base 114 via a plurality of spacers 116. Stage support 1
14, the spacer 116, and the stage 118 are connected and fixed to each other by means of screws or the like. As a result, the stage 118 moves in the XY direction in association with the deformation of the piezoelectric scanner 112.
It is configured to be scanned in the direction. A square stage opening 120 is formed in the center of the stage 118. Inside the stage opening 120, the stage 1
A prism 122 is arranged at a position corresponding to the central portion of 18. The prism 122 is supported from the outside by a support member 124. The support member 124 passes through a space between the stage support base 114 and the stage 118, that is, a gap due to the height of the spacer 116, and is kept in non-contact with the stage support base 114 and the stage 118 together with the prism 122.

As shown in FIG. 2, the upper surface of the prism 122 is displaced downward by about 0.5 mm from the upper surface of the stage 118. Further, the contact surface between the prism 122 and the supporting member 124 is filled with the filler 1 over the entire circumference thereof.
The gap is filled with 26. The support member 124 includes
An oil sump 128, which is a groove formed around the prism 122, is provided.

As shown in FIGS. 1 and 2, sample 134
The transparent sample table 132 on which is mounted is mounted on the substantially central portion of the stage 118. As described above, since the upper surface of the stage 118 and the upper surface of the prism 122 have a step in the height direction, as can be easily imagined from FIG.
When 32 is arranged as it is, there is a gap between the lower surface of the sample table 132 and the upper surface of the prism 122. At this time, since air exists between the sample table 132 and the prism 122, a layer having a different refractive index exists between the sample table 132 and the prism 122. Therefore, in order to match the difference in the refractive index, as shown in FIG.
And the gap of the sample table 132 is filled.

During the scanning movement of the piezoelectric scanner 112, the stage 118 and the sample stage 132 mounted on the stage 118 scan-move together in association with the scanning movement. on the other hand,
Since the prism 122 is supported independently of these scanning portions, the relative position between the prism 122 and the sample stage 132 changes with the scanning movement, but the presence of the matching oil 130 causes the evanescent wave on the sample surface. Is introduced into the sample stage 132 at an angle so as to generate

Positioning can also be performed by the method disclosed in Japanese Patent Laid-Open No. 3-208246. That is, the piezoelectric body scanner 112 is rapidly moved in a desired direction and stopped immediately thereafter, so that the stage 11
The sample 134 can be placed at a desired position with respect to the probe (not shown) by repeatedly performing an operation such as shifting the sample stage 132 mounted on the probe 8.

When the sample 134, that is, the sample table 132 is to be replaced, as shown in FIG.
32 is moved in the direction of the arrow. Then, the matching oil 130 flows into the groove-shaped oil sump 128 provided so as to surround the outside of the prism 122 due to the surface tension thereof. Since the gap between the contact portion between the prism 122 and the support member 124 is filled with the filler 126, the matching oil 130 does not flow down to the lower surface of the prism 122 or the like and is entirely accumulated inside the oil sump 128. After that, the matching oil 130 accumulated in the oil sump 128 is wiped off with a lens cleaning paper or the like, whereby the processing of the matching oil 130 is completed.

As described above, by providing the means for receiving the matching oil around the prism arranged immediately below the sample table, it is possible to avoid the contamination of the scanning stage means and the like by the matching oil.

[0030]

According to the present invention, when the sample table is removed during the replacement of the sample, optical components such as prisms and other members may be contaminated by matching oil. The scanning stage means of a scanning near-field light microscope is obtained.

[Brief description of drawings]

FIG. 1 is a perspective view showing a main configuration of a scanning stage means of a scanning near-field light microscope according to an embodiment of the present invention.

FIG. 2 is a side sectional view of the scanning stage means in FIG. 1 showing a state in which the sample stage is placed and a state in which the sample stage is removed.

FIG. 3 shows a scanner system applicable to a scanning near-field optical microscope proposed in Japanese Patent Application No. 6-169597.

[Explanation of symbols]

112 ... Piezoelectric scanner, 118 ... Stage, 122 ...
Prism, 124 ... Support member, 128 ... Oil pool.

Claims (2)

[Claims] 1. A stage on which a sample stage for mounting a sample is placed, an actuator for moving the stage, an optical member optically coupled to the sample stage via a matching oil, and the optical member is independent of the stage. A scanning stage means for a scanning near-field optical microscope, which comprises a supporting member for supporting the optical member and means for collecting matching oil provided around the optical member. 2. The scanning stage means for a scanning near-field light microscope according to claim 1, wherein the means for collecting the matching oil comprises a groove formed in a supporting member so as to surround the optical member.