JPH0854404A - Atomic force microscope unit - Google Patents

Abstract

PURPOSE:To obtain an atomicforce microscope (AFM) unit which can be incorporated into an optical microscope which is available on the market by installing a coupling part which is coupled to the optical microscope so as to be freely detachable. CONSTITUTION:A base 2 is provided with a coupling part 16 which is used to attach an AFM unit to an optical microscope in a position directly under a sample holder 4 on its bottom face. The coupling part 16 has a structure corresponding to the stage mounting part of a substage. When the optical microscope is to be used as an ordinary optical microscope, a unit frame 5 is lowered, and a cantilever holder 7 is detached. In this state, a sample S which is held by the sample holder 4 is observed by an objective lens 101. After that, when the sample is to be observed by the AFM unit, the unit frame 5 is raised, and the catilever holder 7 is mounted in the central hole of the unit frame 5. In addition, an incidence-side reflecting mirror 11 is moved directly above a cantilever 6. By this operation only, the sample can be observed by the AFM unit.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an atomic force microscope equipped with an optical microscope.

[0002]

2. Description of the Related Art In recent years, a scanning probe microscope utilizing a principle completely different from that of conventional optical microscopes, electron microscopes, etc. has been developed and attracted attention. The scanning probe microscope detects irregularities on the surface of a sample by tracing the surface of the sample with a probe.

One of such scanning probe microscopes is an atomic force microscope (AFM).
There is e). Atomic force microscopes are capable of observing non-conductive substances such as living organisms, organic molecules, and insulating substances (for example, ceramics) on a nanometer scale, and thus are expected to have a wide range of applications. The AFM is a microscope that obtains an image by detecting an atomic force acting between a probe and a sample.

The principle of the AFM and the structure of the main part will be described with reference to FIG.

The AFM can be roughly divided into a structure for holding a sample (hereinafter referred to as "sample holding unit") and a structure for detecting the shape of the sample (hereinafter referred to as "detection unit").

The sample holder is composed of a sample holder 4 ', a scanner 8', and a Z stage 3 '. The sample holder 4'is a table on which the sample s is placed. The sample holder 4'is moved to a desired position by the scanner 8'and the Z stage 3 '. Further, the scanner 8'moves the sample holder 4'by a small amount, so that the probe on the surface of the sample s (described later)
Is being scanned. The Z stage 3'is for moving these up and down.

On the other hand, the detecting section is composed of a light source 9 ', a collector lens 10', a cantilever 6 ', and a detector 13'.

The cantilever 6'represents the shape of the sample surface as
This is detected as the amount of deflection of the cantilever 6 '. The cantilever 6'is formed in a leaf spring shape and has a probe at its tip. The cantilever 6'is bent by the interatomic force acting between the probe and the sample surface.

The light source 9 ', the collector lens 10', and the detector 13 'are for detecting the amount of deflection of the cantilever 6'. The light emitted from the light source 9'is applied to the cantilever 6'through the collector lens 10 ', and the reflected light is detected by the detector 13'. By measuring this reflected light, the amount of deflection of the cantilever 6'can be measured.

The magnitude of the interatomic force acting between the sample surface and the probe changes depending on the distance between the two. Generally, on the surface of a substance, attractive force works at a long distance, and repulsive force works at a short distance. Therefore, keeping the atomic force constant (ie,
By moving the probe along the surface of the sample while keeping the amount of deflection of the cantilever 6'constant (Fig. 8).
In this example, the sample holder 4 ′ side is actually moved), and the unevenness of the sample surface can be observed.

By subjecting the measurement data thus obtained to an appropriate treatment, an image showing the unevenness of the sample surface can be obtained.

Since such an atomic force microscope has a high observation magnification and an extremely narrow observation range, there is a problem in that it is difficult to specify the observation target position by itself. Therefore, in order to cope with this, by separately providing a configuration similar to that of the optical microscope, it has been developed that the actual observation work can be quickly performed. For example, Japanese Patent Laid-Open No. 5-40034 discloses AFM.
And a compound microscope with an optical microscope is described.

[0013]

However, in the above-mentioned prior art, the cost is increased by providing a dedicated structure for the optical microscope (for example, a dedicated optical system). Therefore, there has been a demand for a device that can perform observation with an optical microscope and observation with a scanning probe microscope at low cost.

An object of the present invention is to provide an atomic force microscope unit that can be incorporated in a commercially available optical microscope.

[0015]

The present invention has been made in order to achieve the above object, and in one aspect thereof, a cantilever having a probe for scanning the surface of the sample, and a light to the cantilever are provided. Light irradiating means for irradiating, and detection means for detecting reflected light of the light irradiating the cantilever by the light irradiating means, and the light irradiating means irradiates the cantilever with light from directly above the cantilever. An atomic force microscope unit is provided that is configured to include an optical member, and the optical member is configured to be capable of changing its position at least in a horizontal plane.

The optical member may be a mirror.

According to a second aspect of the present invention, in an atomic force microscope unit that can be attached to an optical microscope to observe a sample, a sample holder for holding the sample and a probe for scanning the surface of the sample are provided. A cantilever, a light irradiating means for irradiating the cantilever with light, a detecting means for detecting reflected light of the light irradiating the cantilever by the light irradiating means, and a connecting portion detachably connected to the optical microscope. There is provided an atomic force microscope unit having:

It is preferable that the connecting portion is arranged directly below the sample holder.

It is preferable that the connecting portion has a light flux hole for passing light at a substantially central position of the connecting portion.

The light irradiating means includes an optical member for irradiating the cantilever with light from directly above the cantilever, and the optical member is configured to be able to change its position at least in a horizontal plane. preferable.

[0021]

[Operation] The connecting portion is connected to the substage of the optical microscope or the like.

When using the optical microscope, the position of the optical member (for example, a mirror) that irradiates light from directly above the cantilever is changed in the horizontal plane and placed at a position deviated from the optical axis of the optical microscope. Then, the light from the light source provided in this optical microscope is applied to the sample placed on the sample holder to perform observation. Therefore, the atomic force microscope unit does not interfere with the original use of the optical microscope.

When observing with an atomic force microscope,
The above-mentioned optical member is located right above the cantilever. Then, the light irradiation means, the detection means, and the calculation means are operated to perform observation.

[0024]

An embodiment of the present invention will be described with reference to the drawings.

The present embodiment is an AFM unit which can be attached to a commercially available optical microscope and used.

First, an outline of an optical microscope to which the scanning probe microscope unit of this embodiment is attached will be described with reference to FIG. However, FIG. 1 shows a reflection illumination type optical microscope. Also, instead of the stage, the AFM of the present embodiment
The drawing shows the state in which the unit 1 is attached.

As is well known, the optical microscope 100 is for observing a sample mounted on a stage (not shown) by enlarging it with an objective lens 101 and an eyepiece lens 102. There is a working distance ΔL ′ between the sample placed on the stage and the objective lens 101, and the focus is adjusted by moving the stage up and down within the range of this working distance ΔL ′. The light required for observation is emitted from the light source 110 and is guided to the sample on the stage through the objective lens 101. Then, it is reflected by the sample and again
It is observed through the eyepiece 102 through the objective lens 101.

This stage (not shown) is a sub-stage 1 which moves up and down according to the operation of the focusing handle 106.
It is detachably attached to 03. The movement of the stage in the vertical direction is realized by the movement of the sub-stage 103.

As shown in FIG. 2, the sub-stage 103 has a light beam hole 104 in the center thereof for passing light. A stage mounting portion 105 is provided around the light flux hole 104. The stage mounting portion 105 is generally configured to include a circular dovetail mount 1050 as shown in FIG. On the side of the stage, a connecting portion having a structure connectable to the stage mounting portion 105 is provided. Therefore, by attaching this connecting portion to the stage attaching portion 105, the both (stage and sub-stage) are detachably connected.

The sub-stage 103 further includes a main body mounting dovetail portion 108. This mounting dovetail portion 108
Of the sub-stage 1 by inserting the guide into the guide 107 that operates according to the operation of the focusing handle 106 equipped with a gear.
Reference numeral 03 is attached to the microscope main body so as to be vertically movable.

Next, the AFM unit 1 of this embodiment will be described.

As shown in FIG. 1, the AFM unit 1 of this embodiment is used by being attached to the sub-stage 103 instead of the above-mentioned stage.

As shown in FIG. 3 or 4, the AFM unit 1 includes a base 2, a Z stage 3, a sample holder 4, a unit frame 5, a cantilever 6, a cantilever holder 7, a scanner 8, a light source 9 and a collector lens 1.
0, incident side reflection mirror 11, detection side reflection mirror 12, detector 13, vertical movement feed screw 14, case 15
(See FIG. 1), the connecting portion 16 and the like.

The base 2 is for supporting the entire AFM unit. The base 2 is provided with a screw hole 20 formed on the inner peripheral surface thereof. And this hole 2
A feed screw 14 for movement is passed through 0. By rotating the screw 14 by holding the knob portion 140 and changing the height position of the screw 14, the height position of the unit frame 5 described later is changed.

Further, the base 2 has a connecting portion 16 on the bottom surface thereof just below the sample holder 4 for attaching the present AFM unit to the optical microscope 100. The connecting portion 16 has a structure corresponding to the stage mounting portion 105 of the sub-stage 103. That is, as shown in FIG. 5, the fixed claws 160a arranged corresponding to the round dovetail mount 1050 of the stage mounting portion 105,
b, and a movable claw 162 whose protrusion amount is adjustable. The movable claw 162 is configured as a feed screw. The movable claw 162 moves in the direction shown by the arrow A in FIG. 5 by turning the knob 163, and the amount of protrusion thereof can be changed. In the present embodiment, the "connecting portion" referred to in the claims is this connecting portion 16.
Is equivalent to

At the center of the base 2 (center of the connecting portion 16), there is provided a light beam hole 22 for passing light for an optical microscope as shown in FIGS. Light can also pass through the sample holder 4, the Z stage 3, the scanner 8 and the like (in this embodiment, holes are formed). The luminous flux “hole” does not necessarily have to be a hole. A "window" made of light-transmissive material (eg glass)
It may be configured as. In the present embodiment, the light flux hole 22, the window, etc. described here correspond to the "light flux hole" in the claims.

The unit frame 5 includes a cantilever holder 7, a light source 9, a collector lens 10 and an incident side mirror 1.
1, for attaching the detection side mirror 12, the detector 13 and the like (see FIG. 3).

As shown in FIG. 6, the unit frame 5 has a central hole 5 for mounting the cantilever holder 7.
One. Note that FIG. 6 illustrates a state in which the cantilever holder 7 is attached. The edge of the central hole 51 is provided with a connector groove 52 for accurately defining the position of the cantilever holder 7. When using the optical microscope 100, the sample holder 4 and the like project above the unit frame 5 through the central hole 51. Therefore, the central hole 51 is sufficiently large for this purpose.

The unit frame 5 is provided with legs 50 at various places on its lower surface (see FIG. 3). The unit frame 5 mounts the legs 50 on the head end surface of a vertical movement feed screw 14 described later.

The cantilever 6 is attached to the cantilever holder 7 shown in FIG. 7, and is configured to be attached to the unit frame 5 only when observing with an AFM. The cantilever 6 itself is the same as the conventional one.

As shown in FIG. 7, the cantilever holder 7 has a substantially square holder body 70, a cantilever 6, and
And a connector portion 72. The holder body 70 is provided with a light passing hole 71 for passing light for measuring the amount of bending of the cantilever 6. Cantilever holder 7
By fitting the connector portion 72 into the connector groove 52 of the unit frame 5, the connector portion 72 can be attached to the unit frame 5 in a state where its position and angle are accurately defined. The cantilever 6 is attached to the lower surface of the holder main body 70 in a state in which the probe portion thereof projects into the light transmitting hole 71. The probe of the cantilever 6 is set to be located on the optical axis Ar of the optical microscope 100 when the cantilever holder 7 is attached to the unit frame 5 (this visually confirms the observation position by the AFM). It is for the purpose of doing).

The light source 9, the collector lens 10 and the incident side mirror 11 are for irradiating the cantilever 6 with light for measuring the amount of deflection of the cantilever 6. These are attached to the upper surface side of the unit frame 5 (see FIG. 3). In this embodiment, since it is possible to irradiate the cantilever 6 with light from directly above, the incident side mirror 11 is configured to be movable so that its position in the horizontal direction can be changed (in the figure, Shows an example in which not only the incident side mirror 11 but also the collector lens 10 and the light source 9 can be moved. The "optical member that irradiates the cantilever with light from directly above the cantilever" in the claims corresponds to the incident side mirror 11 in this embodiment. When observing with the AFM, as shown in FIG. 3, the incident side mirror 11 is positioned directly above the cantilever 6. On the other hand, the optical microscope 10
When observing at 0, the incident side mirror 11 is moved and displaced from the optical axis Ar. The configuration for this movement is not particularly limited. For example, a groove may be provided on the upper surface of the unit frame 5, and the incident side mirror 11 may be moved along the groove.

Detecting-side reflecting mirror 12 and detector 1
3 is for detecting the light reflected by the cantilever 6 (see FIG. 3). The reflected light of the light applied to the cantilever 6 via the incident side mirror 11 is reflected by the detection side reflection mirror 12 toward the detector 13. The detector 13 detects this reflected light and outputs it to an analysis calculation unit (not shown). In addition,
This analysis calculation unit may be provided in the AFM unit 1 itself, or may be realized by a separately prepared computer or the like.

The method of use will be described.

The AFM unit 1 is attached to the sub-stage 103
In order to attach it, the knob 163 (see FIG. 5) is operated so that the movable claw 162 is retracted (moved to the outer peripheral side). Next, the fixed claw 160 is hung on the round dovetail mount of the stage mounting section 105 (put in the lower side of the dovetail section). Then, as it is, the knob 163 is operated to move the movable claw 162 to the inner peripheral side. By the above operation, the three claws (160, 162) do not disengage from the circular dovetail mount portion of the stage mounting portion 105. To remove the AFM unit 1, the knob 163 may be operated to move the movable claw 162 to the outer peripheral side.

When used as an ordinary optical microscope,
As shown in FIG. 3, the unit frame 5 is lowered and the cantilever holder 7 is removed. In addition, the incident side mirror 11
Is shifted in position from the optical axis Ar so as not to hit the sample holder 4 and the objective lens 101.

In this state, the sample s held on the sample holder 4 can be observed by the objective lens 101. The focus adjustment can be performed by operating the focusing handle 106 and moving the sub-stage 103 up and down with the AFM unit 1 mounted. Therefore, the presence of the AFM unit 1 does not hinder the use of the optical microscope 100.

After that, when the observation by the AFM is continued, the unit frame 5 is raised and the cantilever holder 7 is attached to the central hole 51 of the unit frame 5. Further, the incident side mirror 11 is moved so as to be located right above the cantilever 6.

The replacement of the sample s is easy if the unit frame 5 is lowered as shown in FIG.

The sample can be observed by the AFM simply by performing the above operation. After this, the sample may be observed as it is. That is, the scanner 8 or the like is operated to operate the surface of the sample s with the probe of the cantilever 6, and
The amount of deflection of the cantilever 6 is detected by using the detector 13 or the like.

In this embodiment, the stage attached to the sub-stage 103 of the optical microscope 100 is usually removed and the AFM unit 1 is attached. However, as long as a sufficient working distance ΔL can be secured, the AFM unit 1 may be placed on the stage and used without removing the stage. However, it is necessary to pay attention so that the probe of the cantilever 6 does not shift from the position on the optical axis Ar. A means for fixing (connecting) to the stage may be separately provided.

The concrete shape structure of the connecting portion 16 provided on the bottom surface of the base 2 may be any structure as long as it is compatible with the stage mounting portion 75 of the sub-stage 103.

In the above embodiment, the vertical movement feed screw 14 is used.
Had to be manually rotated. However, if it is operated by using a motor or the like, the operability is further improved.

In this embodiment, the cantilever 6 and the cantilever holder 7 are detachable from the unit frame 5, while the incident side reflection mirror 11 can change its position in the horizontal plane.
It was set so as not to obstruct the observation with the optical microscope. However, the incident-side reflection mirror 11 may also be attached to the cantilever holder 11 and attached / detached together with the cantilever 6. By doing so, the number of movable parts in the AFM unit 1 can be reduced, and the cost can be reduced. Further, since the relative position and angle of the incident side reflection mirror 11 and the cantilever 6 are reliably fixed, it is not necessary to perform fine adjustment of the position and angle of the incidence side reflection mirror 11 each time observation is performed, and operability is improved. Is improved. Furthermore, the AFM unit 1 of the present embodiment is premised on being incorporated in a commercially available optical microscope, so that the working distance ΔL is not always sufficient. When the margin of the working distance ΔL is small, the objective lens 101 may be lowered by mistake while the incident side reflection mirror 11 is positioned on the optical axis, and the incident side reflection mirror 11 may be damaged. Conceivable. Even in such a case, the incident side mirror 11
By exchanging (with the cantilever holder 7), the observation can be immediately continued. However, when such a configuration is adopted, when the cantilever 6 is broken,
It is preferable in terms of operating cost to remove only the cantilever 6 from the cantilever holder 7 so that it can be replaced with a new cantilever (if the cantilever 6 cannot be removed from the cantilever holder 7, the incident side mirror 11 and the like will also be replaced). This will increase operating costs).

On the contrary, the cantilever holder 7 may be constructed so that its position in the horizontal plane can be changed. In this case as well, it is preferable in terms of operating cost to remove only the cantilever 6 from the cantilever holder 7 and replace it with a new cantilever.

It goes without saying that the various configurations described above may be combined as appropriate. For example, the incident side mirror 11 and the cantilever 6 are installed in the cantilever holder 7,
Further, the cantilever holder 7 may be configured to be detachable from the unit frame 5 and capable of changing its position in the horizontal plane.

In the embodiment described above, the AFM unit 1
It is not necessary for itself to be equipped with an optical system for confirming the observation position of the sample surface. Therefore, the price of the AFM unit can be suppressed. Further, in an atomic force microscope equipped with an optical system, the optical system is for confirming the observation position of the atomic force microscope, and therefore its magnification is limited to some extent. On the other hand, in the present invention, since a commercially available optical microscope is used, the sample can be optically observed from low magnification to high magnification. Further, when the optical observation is performed, the incident side mirror 11 is moved to a position where it does not interfere, so that the image does not become dark when the optical observation is performed.

Further, the user can effectively use the optical microscope already possessed.

Further, in the commercially available optical microscope,
Various accessories for performing various observations such as fluorescence / differential interference are sold. Therefore, by using these accessories, it is possible to more efficiently and surely determine the position where the observation by the atomic force microscope is performed.

From the beginning, if a microscope system including the AFM unit of the present invention as an option for system upgrade, more efficient observation becomes possible.

[0061]

As described above, according to the present invention, an atomic force microscope unit that can be observed by an optical microscope can be provided at a low cost by using a commercially available optical microscope. Also, the user can effectively use the optical microscope that he already has.

[Brief description of drawings]

FIG. 1 is an external view of an optical microscope equipped with an AFM unit that is an embodiment of the present invention.

FIG. 2 shows details of a sub-table of the optical microscope (a).
It is a top view and a (b) side view.

FIG. 3 is a schematic front view showing the outline of the structure of the AFM unit of the present invention.

FIG. 4 is a schematic front view showing a state at the time of observation by the AFM of the present invention.

5 is a bottom view of the base 2. FIG.

FIG. 6 is a top view of a unit frame.

7 (a) is a plan view, FIG. 7 (b) is a side view, and FIG. 7 (c) is a rear view showing details of a cantilever holder.

FIG. 8 is a schematic diagram showing an outline of a conventional scanning probe microscope.

[Explanation of symbols]

1 ... AFM unit, 2 ... base, 3 ... Z stage, 4
... sample holder, 5 ... unit frame, 6 ... cantilever, 7 ... cantilever holder, 8 ... scanner, 9 ...
Light source, 10 ... Collector lens, 11 ... Incident side reflection mirror, 12 ... Detection side reflection mirror, 13 ... Detector, 14
... Feed screw for vertical movement, 15 ... Case, 16 ... Coupling part,
20 ... Hole, 22 ... Luminous flux hole, 50 ... Leg part, 51 ... Central hole,
52 ... Connector groove, 70 ... Holder body, 71 ... Light passing hole,
72 ... Connector part, 100 ... Optical microscope, 101 ... Objective lens, 102 ... Eyepiece lens, 103 ... Substage,
104 ... Luminous flux hole, 105 ... Stage mounting part, 106 ...
Focusing handle, 107 ... Guide, 108 ... Main body mounting dovetail part, 110 ... Light source, 140 ... Knob part, 160 ... Fixed claw, 162 ... Movable claw, 163 ... Knob, s ... Sample,
Ar ... Optical axis, ΔL ... Working distance

Claims (6)

[Claims] 1. A cantilever having a probe for scanning the surface of a sample, a light irradiating means for irradiating the cantilever with light, and a detecting means for detecting reflected light of the light irradiating the cantilever by the light irradiating means. And the light irradiating means is configured to include an optical member that irradiates the cantilever with light from directly above the cantilever, and the optical member and the cantilever are configured such that at least a position in a horizontal plane can be changed. Atomic force microscope unit characterized by being. 2. The atomic force microscope unit according to claim 1, wherein the optical member is a mirror. 3. An atomic force microscope unit capable of observing a sample mounted on an optical microscope, comprising: a sample holder for holding the sample; a cantilever provided with a probe for scanning the surface of the sample; Light emitting means for irradiating the cantilever, detecting means for detecting reflected light of the light applied to the cantilever by the light emitting means, and a connecting portion detachably connected to the optical microscope. Atomic force microscope unit. 4. The atomic force microscope unit according to claim 3, wherein the connecting portion is arranged directly below the sample holder. 5. The atomic force microscope unit according to claim 4, wherein the connecting portion has a light beam hole for passing light at a substantially central position of the connecting portion. 6. The light irradiating means includes an optical member for irradiating light onto the cantilever from directly above the cantilever, and the optical member is configured to be able to change at least a position in a horizontal plane. The atomic force microscope unit according to claim 3, wherein