JPH045502A - Probe inspecting method - Google Patents

Abstract

PURPOSE:To evaluate a probe, to grasp the measurement accuracy of a device, and to grasp the optimum scanning direction by taking a measurement while rotating a standard sample which has a perpendicular surface at the same angle as the angle of the scanning direction of the probe. CONSTITUTION:The standard sample 9 is arranged in such a direction that the Y-axial scanning direction of the probe 8 matches the pattern direction of the standard sample 9 and the perpendicular surface of the pattern comes to the side of the probe 8 in an X-axial scanning direction. In such a state, the probe 8 is put in X-axial scanning motion. Then an angle signal generator 4 generates an optional-angle signal theta and the angle between the scanning direction of the probe 8 and the sample 9 is rotated by the same angle to put the probe in scanning motion. Thus, the probe is put in the scanning motion while the sample 9 and scanning direction are rotated by the same angle to put the probe 8 in the scanning motion in the repetitive direction of the pattern of the standard sample 9 at all times. This is repeated to one rotation (350 deg.). Thus, the angle signal theta is varied over the entire periphery from 3 deg. to 360 deg. to obtain the track 11 of the tip of the probe 8, and consequently the inclination of the tip over the entire periphery of the probe 8, thereby measurement and inspection of the shape of the probe tip part is attained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for measuring and inspecting the shape of a tip of a probe in a measuring instrument that scans a sample surface with a probe to measure the sample surface shape.

[Summary of the invention]

By measuring a standard sample with a vertical surface while rotating it at the same angle as the scanning direction of the probe and the angle of the sample, the shape of the tip of the probe can be easily measured without using any special equipment. This method is simple and efficient, and makes it possible to evaluate the probe, understand the measurement accuracy of the device, and understand the optimal scanning direction.

[Conventional technology]

For example, by using the tunnel effect to keep the distance between the sample surface and the probe constant, the probe is scanned in the in-plane direction along the sample surface, and from the height information of the probe at this time, the sample surface is STM (scanning tunneling microscope) to obtain three-dimensional microscopic shapes
Although the shape of the tip of the probe greatly affects the measurement accuracy of STM, there was no suitable method for easily measuring and inspecting it.

[Problem to be solved by the invention]

Although the shape of the tip of the probe greatly affects the measurement accuracy of STM, it is difficult to maintain it constant, so each time the tip is replaced, the shape of the probe tip and the scanning direction are different. Therefore, there was a problem that differences occurred in the obtained 37M measurement images.

[Means to solve the problem]

For example, as in some optical diffraction gratings, elongated patterns or grooves are formed in a certain direction with a vertically cut surface, and the same patterns are lined up at a fine pitch. Using a standard sample, the scanning direction of the probe can be rotated 360° using a means for rotating the scanning direction of the probe in an arbitrary direction and a means for rotating the sample in an arbitrary direction.
The shape of the tip of the probe can be determined over the entire circumference by rotating the sample around the entire circumference, and by rotating the sample so that the probe is always scanned in the repeating direction of the pattern of the standard sample and measuring the minute shape of the standard sample. This is a method of inspection.

[Effect]

By using the above method, it is possible to measure and inspect the shape of the tip of the probe, and by knowing the shape of the tip of the probe, it is possible to understand the measurement accuracy of the 37M measurement image of the sample, and also to understand the shape of the tip of the probe. By knowing this, it becomes possible to grasp the optimal scanning direction and also to evaluate the probe during probe production.

[Embodiment] FIG. 1 shows the configuration of an example of an apparatus used in the present invention. The X-direction scanning signal X generated from the X-axis scanning signal generator 1 and the Y-direction scanning signal generated from the Y-axis scanning signal generator 2 are both input to the scanning signal converter 3. The scanning signal converter 3 is also inputted with an angle signal θ generated from an angle signal generator 4, and in accordance with this angle signal θ, it converts signals X and Y from the X-axis and Y-axis scanning signal generators 1.2. Rotate and transform YSINθ + cosθ, yccsθX5I respectively
It is converted into a signal called Nθ and output. Each of the output signals is applied to the X-axis electrode 6 and the Y-axis electrode 7 on the cylindrical piezoelectric element 5, so that the probe 8 attached to the tip of the cylindrical piezoelectric element 5 is connected to the X-axis electrode 6. and the Y-axis electrode 7, the probe 8. The tunnel current between the samples 9 will be measured. Further, a standard sample 9 placed at a position facing the probe 8 is mounted on a sample rotation table 10.
The sample rotation table 10 rotates the standard sample 9 at an angle corresponding to the angle signal θ from the angle signal generator 4. Since the same angle signal θ is input to the scanning signal converter 3 and the sample rotation table 10, the scanning direction of the probe 8 and the mounting direction of the standard sample 9 always rotate by the same angle. .

As shown in FIG. 2, the standard sample 9 has grooves of the same pattern formed vertically on one side wall of the cross section arranged in a fine pinch.

Now, first, the Y-axis scanning direction of the probe 8 and the pattern direction of the standard sample 9 should match (as shown in FIG. 2, which shows an example of the standard sample used in the present invention and the arrangement direction). , furthermore, the vertical plane 1 of the pattern is on the X-axis scanning direction side of the probe 8.
The standard sample 9 is arranged in such a direction that 2 is facing. In this state, the probe 8 is scanned in the X-axis direction. Next, the angle signal generator 4
An arbitrary angle signal θ is generated from , and the probe 8 is scanned by rotating the probe 8 by the same angle as the scanning direction of the probe 8 and the angle of the sample F49. When the probe 8 is scanned by rotating the scanning direction at the same angle as the sample 9 in this manner, the probe 8 is always scanned in the repeating direction of the pattern of the standard sample 9. This process is then repeated up to one rotation (360°).

FIGS. 3(a) and 3(a) to 3(a) are diagrams illustrating a scanning situation with a probe having different cross-sectional shapes on the left and right sides. Figure 3 +a+ shows the scanning direction and the scanning situation before rotating the standard sample 9 (Oo), and Figure 3 (g)) shows the scanning direction and the scanning situation when the standard sample 9 is rotated at 180 degrees.
This shows the scanning situation when rotated. As can be seen from these figures, the trajectory 11 of the tip of the probe 8 changes depending on the shape of the probe 8 even though the standard sample 9 is always scanned in the same direction. What should be noted here is that among the trajectory 11 of the tip of the probe 8, the standard sample 9
The inclination of the portion corresponding to the vertical plane directly indicates the inclination of the tip of the probe 8. Therefore, if the angle signal θ is varied over the entire circumference from 0 to 360° to obtain the locus 11 of the tip of the probe 8, the inclination of the tip over the entire circumference of the probe 8 can be obtained. A metrological inspection of the shape of the tip is accomplished.

〔Effect of the invention〕

As described above, by establishing a method for measuring and inspecting the shape of the probe tip, it becomes possible to grasp the measurement accuracy when measuring a sample, and it also becomes possible to grasp the optimal scanning direction. What is noteworthy here is that all of this work can be done without the use of any special equipment, with the probe being used to measure the shape of the sample surface attached to the measuring device. Therefore, it is an extremely simple and efficient method that only requires measuring the -scanning line segment of a predetermined standard sample several times at different angles.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of the device used in the present invention,
FIG. 2 is a diagram showing an example of a standard sample used in the present invention and its arrangement direction, and FIGS. 3(a) and (1) are diagrams showing the relationship between the shape of the sample and the shape of the probe before and after rotation. 3...Scanning signal converter 4...Angle signal generator 5...Cylindrical piezoelectric element 6...X thin electrode 7...Y thin electrode 8...Tip 9...Standard sample 10 ... Sample rotation table 11 ... Probe tip trajectory 12 ... Vertical surface of pattern

Claims (1)

[Claims] Using a standard sample with a repeating vertical plane, a means for rotating the scanning direction of the probe, and a means for rotating the sample direction, the probe can be probed while changing the angle of the probe scanning direction and the angle of the sample at the same angle. A probe inspection method that measures and inspects the shape of the probe tip by scanning the probe.