JP2000097840A - Scanning probe microscope - Google Patents

Abstract

PROBLEM TO BE SOLVED: To observe even a large-sized sample without dividing it, and to obtain a more accurate surface structure by scanning the fixed sample surface with a probe and observing the large sample surface at an optional position by moving an observation unit. SOLUTION: This scanning probe microscope has a means for moving an observation unit 3 to an optional position on the sample surface, and the large sample surface can be observed at an optional position by making a probe scan parallel to the sample surface. The moving means of the observation unit 3 has a vibration removal or damping means 4 and comprises two moving means. Namely, a second moving means 2 supplements the positioning accuracy of a first moving means 1 having a large moving range, and its positioning accuracy is higher than the positioning accuracy of the first moving means 1, and its moving range is smaller than the scanning range of the probe. Hereby, the high-accuracy positioning and the wide moving range are compatible, and the probe can be moved accurately to an optional minute region on the large sample surface, such as a master disc of a compact disc, to thereby execute measurement.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an atomic force microscope used for observing a fine structure on a sample surface.

[0002]

2. Description of the Related Art FIG. 8 is a block diagram of an atomic force microscope which is one of conventional scanning probe microscopes. In the figure,
10 is an XYZ translator, 11 is a sample stage, 12
Is a sample, 5 is a cantilever, 13 is a cantilever deflection detector, and 14 is a computer and a controller.

In this conventional scanning probe microscope, a sample is placed on a sample stage on an XYZ translator, the sample is brought into contact with a sharpened probe fixed to the tip of a cantilever, and the sample is scanned in the XY plane by the translator. I do. At this time, the flexure of the cantilever is monitored by the 13 flexure detectors, the controller performs feedback control so that the flexure becomes constant, and the translator adjusts the position of the sample in the Z direction. By mapping the adjustment amount at each position on the sample surface on a screen by a computer, a fine structure on the sample surface can be observed.

[0004]

As shown in FIG. 8,
In the conventional scanning probe microscope, the size of a measurable sample is limited to several cm or less because the sample is mounted on the XYZ translator. In the case of a sample larger than this, it is necessary to divide the sample into small pieces. However, for example, when evaluating pits formed on a compact disk master, it is difficult to measure because the master cannot be divided.

Further, in the conventional scanning probe microscope, it is difficult to obtain an accurate surface structure for a sample having a steep step having a slope angle of 60 degrees or more (hereinafter referred to as a steep step). In FIG. 9, reference numeral 5 denotes a cantilever having a probe at the tip, reference numeral 9 denotes a sample surface shape obtained by scanning the probe, and reference numeral 7 denotes a sample having a steep step. When the probe scans a steep step, in a state where the probe goes down the step, as shown by a dotted line 9, the response speed of the control system including the cantilever,
Due to the influence of the probe shape, it is observed as a step that is gentler than the actual step. Conversely, in a state where the probe climbs a step, similarly, the response speed of the control system and the effect of the shape of the probe remain, but are observed as a step closer to the actual shape. As described above, the conventional scanning probe microscope has a problem that an accurate surface structure cannot be obtained with a sample having a steep step.

Therefore, in the present invention, it is possible to observe a large sample such as a master disc of a compact disk without dividing the sample, and to obtain a more accurate surface structure even for a sample having a steep step. It is an object to provide a scanning probe microscope.

[0007]

In a scanning probe microscope according to the present invention, a probe is brought close to a sample surface and a fine movement mechanism for scanning the sample surface and a mechanism for detecting a distance between the probe and the sample surface are provided. Was arranged on the probe side, and the probe was scanned over the surface while the sample was fixed. Furthermore, in order to enable observation at an arbitrary position on the large sample surface, a configuration is provided having means for moving the observation unit. Further, in order to achieve both high-precision positioning and a wide movable range, a plurality of moving units having different movable ranges and different positioning accuracy are provided.

In addition, a plurality of cantilevers are arranged to face each other, and after a series of surface scans, scanning is performed in a reverse direction so that a steep step can be accurately measured. Also,
After a series of surface scans, the configuration is such that steep steps can be accurately measured by scanning while changing the direction of the probe. In addition, a steep step can be accurately measured by changing the angle of the probe or the sample and scanning, and further, a fine structure on the side surface of the step can be measured.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. [Embodiment 1] In FIG. 1, 1 is a first moving means, 2
Denotes a second moving unit, 3 denotes an observation unit, and 4 denotes a vibration isolation or vibration suppression unit. The second moving means compensates for the lack of positioning accuracy of the first moving means having a large movable range. The movable range is at least equal to or greater than the positioning accuracy of the first moving means, and the positioning accuracy is at least the scanning range of the scanning probe microscope. It is as follows. With such a configuration, the probe can be accurately moved to an arbitrary minute area on the surface of a large sample such as a master disk of a CD.

[Embodiment 2] In FIG. 2, reference numeral 5 denotes a cantilever, and reference numeral 6 denotes a probe. In FIG. 3, 7 is a sample having a steep step, and 8 and 9 are shapes obtained when the probe scans the surface of 7. The cantilevers are arranged face to face as shown in FIGS. 2a and 2b, and when scanning from left to right in FIG. 3, use the right probe in FIG. 2a or b, and scan from right to left in reverse. Sometimes the other cantilever is used. Further, as shown by solid lines 8 and 9 in FIG. 3, the shapes obtained when the probe climbs the step in each scanning direction are combined. With such a configuration, even in a sample having a steep step, the step shape can be measured more accurately. Further, the arrangement of the cantilevers is set as shown in FIG. 2C, and by performing the same operation, the shape of the step in all directions can be measured with high accuracy.

[Embodiment 3] In FIG. 4, 5 is a cantilever, 6 is a probe, 7 is a sample having a steep step, 8
And 9 are the shapes obtained when the probe scans the surface of 7. After the cantilever is arranged in the direction of a and scanning is performed from left to right, the direction of the cantilever is changed as shown in b and scanning is performed from right to left. Then, as shown by solid lines 8 and 9 in each scanning direction, the shapes obtained when the probe climbs the step are combined. With such a configuration, even in a sample having a steep step, the step shape can be measured more accurately.

[Embodiment 4] In FIG. 5, 5 is a cantilever, 6 is a probe, and 7 is a sample having a step.
As shown in b, the angle formed by the side surface facing the probe traveling direction and the horizontal plane of the sample is α, and the angle formed by the side surface of the step and the horizontal surface of the sample is β. When there is a step on the sample surface such that α ≦ β as shown by a, the probe or sample is inclined so that α> β as shown by c and d. With such a configuration, it is possible to measure not only the exact shape of the step but also the fine structure of the side surface of the step.

[Embodiment 5] In FIG. 6, 3 is an observation unit, 5 is a cantilever, 6 is a probe, 7 is a sample having a steep step, 15, 16 and 17 are piezoelectric bodies, 18
Is a fulcrum. The probe is tilted by extending one of the two piezoelectric members 15 and 16 and contracting the other as shown in a, or by expanding and contracting the seventeen piezoelectric members as shown in b. With such a configuration, the probe can be easily inclined, and not only the accurate shape of the step but also the fine structure on the side surface of the step can be measured.

[Embodiment 6] In FIG. 7, 3 is an observation unit, 5 is a cantilever, 6 is a probe, 7 is a sample having a steep step, and 13 is a deflection detector. As shown in FIG. 7, by tilting the entire observation unit, the probe can be tilted without changing the relative positional relationship between the cantilever and the deflection detector. With such a configuration, for example, the probe can be tilted without shifting the optical axis in the optical lever system,
It is possible to measure not only the exact shape of the step but also the fine structure of the side surface of the step.

[0015]

As described above, according to the present invention,
A large sample can be measured without division by a scanning probe microscope, and the probe can be accurately moved to any minute area on the sample surface for measurement. Further, even for a sample having a steep step, more accurate shape measurement by a scanning probe microscope can be performed, and in addition, a minute structure on the side surface of the step can be measured.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a scanning probe microscope according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a scanning probe microscope according to a second embodiment of the present invention.

FIG. 3 is an explanatory diagram showing a principle of measuring a level difference of a scanning probe microscope according to a second embodiment of the present invention.

FIG. 4 is an explanatory diagram of a scanning probe microscope according to a third embodiment of the present invention.

FIG. 5 is an explanatory diagram of a scanning probe microscope according to a fourth embodiment of the present invention.

FIG. 6 is an explanatory diagram of a scanning probe microscope according to a fifth embodiment of the present invention.

FIG. 7 is an explanatory diagram of a scanning probe microscope according to a sixth embodiment of the present invention.

FIG. 8 is a configuration diagram of a conventional scanning probe microscope.

FIG. 9 is a diagram illustrating the principle of operation of a conventional scanning probe microscope on a sample having a steep step.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 1st moving means 2 2nd moving means 3 Observation unit 4 Vibration isolation or vibration suppression means 5 Cantilever 6 Probe 7 Sample with steep step 8, 9 Step shape obtained by operating probe 10 XYZ translator 11 Sample stage 12 Sample 13 Deflection detector 14 Computer and AFM controller 15, 16, 17 Piezoelectric material 18 Support

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2F069 AA60 DD09 DD19 GG01 GG63 GG65 HH04 JJ08 JJ28 MM04 MM38 5H303 AA20 AA30 BB03 BB09 DD14 EE07 FF03 GG20

Claims (9)

[Claims] 1. A scanning probe microscope in which a minute probe scans a surface of a sample to observe a minute structure on the surface of the sample. A mechanism for moving the observation unit having a mechanism for detecting the distance between the probe and the sample and fine movement means for scanning the probe in parallel with the sample surface to an arbitrary position on the sample surface, and observing a sample having a steep step. Means, and a scanning probe microscope. The means for moving the observation unit includes a vibration isolation or vibration suppression means, and further includes a plurality of movement means different in at least one or both of a movable range and a position accuracy. The scanning probe microscope according to claim 1, wherein: 3. The means for moving the observation unit includes two moving means, wherein the movable range of the second moving means is at least as high as the positioning accuracy of the first moving means, and the positioning of the second moving means is performed. 3. The scanning probe microscope according to claim 2, wherein the accuracy is less than a scanning range of the probe. 4. The means for observing a sample having a steep step has a plurality of cantilevers each having a probe at a tip thereof.
2. The scanning probe microscope according to claim 1, wherein the directions of the cantilevers are different, and the scanning direction is different for each cantilever. 5. The means for observing a sample having a steep step comprises arranging two cantilevers each having a probe at a tip thereof, scanning with a first probe, and changing a scanning direction to a second cantilever. The scanning probe microscope according to claim 4, wherein the probe scans the same place as the first probe. 6. The apparatus according to claim 1, wherein the means for observing the sample having a steep step changes the direction of a cantilever having a probe at the tip, changes the scanning direction, and scans the same place. Scanning probe microscope. 7. The apparatus according to claim 1, wherein the means for observing the sample having a steep step includes means for tilting the probe or the sample such that the tip of the probe comes into contact with a side surface of the step on the surface of the sample. Scanning probe microscope. 8. The scanning probe microscope according to claim 7, wherein the means for tilting the probe tilts the probe by tilting a cantilever using a piezoelectric element. 9. The scanning probe microscope according to claim 7, wherein the means for tilting the probe tilts the probe by tilting an observation unit.