JPS63298951A - Scanning microscope - Google Patents

Abstract

PURPOSE:To select a visual field by an SEM observation and to enable it to be observed by an STM observation, by mounting a scanning stylus mechanism and a specimen roughly moving mechanism of a scanning tunnel electron microscope on an objective lens of a scanning electron microscope SEM. CONSTITUTION:A rigid member 5 supports a scanning stylus 3, a scanning mechanism 4 and a base table 7 of a specimen stage 6 and is mounted on an SEM objective lens 1 through a rubber vibration isolator. Lock mechanisms 8a, 8b are secured to the base table 7. When an SEM observation is effected, the mechanisms 8a, 8b are released and a drive units 6x, 6y are moved to observe a specimen 2. Then, an observation area of the STM is selected, the specimen 2 is approached to the stylus 3 by a drive unit 6z, and the stage 6 is fixed by the mechanisms 8a, 8b. Thus, the STM observation is effected by scanning the stylus 3 by the mechanism 4. By this arrangement, a visual field is selected by a wider SEM observation and observed by an STM of a high magnification ratio to provide a picture image of high performance.

Description

[Detailed Description of the Invention] @) Industrial Application Field The present invention is used for analyzing the structure of a sample surface.
Scanning electron microscope (8canning Electron)
Microscope (hereinafter referred to as SEM), scanning Auger analyzer (8canning Auger B Iectr)
on Microanalyzer (hereinafter referred to as 8AM),
Scanning ion microscope
Microscopes using particle beams (referred to as particle beam scanning microscopes) such as RO-5cope (hereinafter referred to as 8IM), and scanning tunneling electron microscopes (8canning tunnel electron microscopes).
ing Microscope.

8TM below), for more details, please refer to Particle Beam Scanning Microscope and Scanning Tunnel/! / Concerning nine devices in combination with an electron microscope (8TM).

(b) Conventional technology Scanning tunnel/l' In an electron microscope (STM), a sharply pointed needle (scanning needle, STM chip) is brought close to the observation sample.
The tunnel/L' current flowing between the two is captured, and the cormorant needle is scanned over the sample surface to create an image.

Figure 2 shows the main part of the scanning tunneling electron microscope (STM unit), in which the scanning needle 13 is supported by a rigid body 15 and has three pressure τ elements 14 x, 14 y, and 14 z for the sample 12. NX, y, z Scan in each direction. In STM observation, the scanning needle 13 is brought close to the sample by the piezoelectric element 14Z until a certain amount of tunnel IVE flows, and the surface of the sample is moved 2 times by the piezoelectric elements 14X and 14ylc.
Dimensional scanning is performed, and the Z-direction drive amount of the scanning needle is extracted as an output signal to construct an image.

This scanning tunneling electron microscope is described in US Pat. No. 43, for example.
Publication No. 43993 (August 10, 1982) and "Science" magazine Vol. 15. No, 10. pplo
17 (October 1, 1985), 1
It has an extremely high resolution of human or better, and has the advantage of being able to observe even the arrangement of atoms on the sample surface. However, in order to obtain such high resolution, a piezoelectric element is used in the mechanism for moving the scanning needle, and since it is not possible to scan a wide area at both speeds, it is difficult to obtain images at low magnification.

On the other hand, particle beam scanning microscopes, such as scanning electron microscopes (S
BM) scans the sample surface with a narrow aperture specific gravity beam,
It is a device that detects signals of secondary electrons emitted from the sample to observe the surface of the sample, and is useful as a stereomicroscope with magnifications ranging from several times to 100,000 times. It is difficult to obtain.

For the above reasons, scanning electron microscopes and scanning tunnels [
In order to observe both STM images and SBM images by combining a submicroscope, nine devices have been devised, in which an 8TM unit (scanning needle and scanning mechanism for the scanning needle) is mounted on an 8EM sample stage, for example.

(c) Problems to be solved by the invention In an apparatus in which an STM unit is attached to a SEM sample stage, even if the sample stage is driven and the 8EM observation area is moved, the 8TM observation area Fii does not change; The vicinity can only be observed by SEM.

Is this the problem with this shout? Finally, the scanning microscope 1 combines the features of a particle beam scanning microscope and STM [currently, it is a scanning microscope that can select an arbitrary field of view through wide-area (low-magnification) observation and then observe that field of view with a high-magnification STM. The main purpose is to

In the present invention, the scanning tunnel/I/[scanning needle scanning mechanism and sample coarse movement mechanism of the child microscope are attached to the objective lens of the particle beam scanning microscope.

(e) Observe a wide-area image using a working particle beam scanning microscope, select the area to be observed using STM, position the area in the center using the sample coarse movement mechanism, and then perform observation using STM scanning. , the desired STM image is obtained.

(To) Example"\1 Bottom, Scanning electron microscope fi as a particle beam scanning microscope
(SEM) will be explained as an example.

Figure 1 shows 8113M and 8TM, which are one embodiment of the present invention.
vi - Shows the main parts of the combined device. In this figure, 1 is an 8EM objective lens, 2 is a sample, and 3 is a scanning needle of a scanning electron microscope. Reference numeral 4 denotes a scanning needle scanning mechanism, which is composed of three piezoelectric elements corresponding to the three axes x, y, and z, as in Fig. 2. Reference numeral 5 denotes a rigid body that supports the scanning needle and the scanning jaw mechanism, and also supports the base 7 of the sample stage (sample rough movement mechanism) 6. The sample stage 6 includes drive devices 6x, 6y, and 6z that move the sample 2 in each of the x, y, and z directions. 3a
, 8b is the base 7 (or rigid body 5) that controls the movement of the sample stage 6.
This is a locking mechanism that fixes the Reference numeral 9 denotes a vibration isolating material, which is composed of alternating layers of elastic plates and rigid plates, and prevents external vibrations from being transmitted to the scanning needle and sample through the objective lens 1 during STM observation. is prevented. Due to the presence of this vibration isolating material 9, vibration may occur between the 8EM objective lens 1 and the sample 2, that is, between the electron beam axis and the sample, so during SBM observation, the rigid body 5 and the 8gM
The space between the objective lenses 1 is fastened and fixed by an anti-vibration lock (not shown).

Observation using the apparatus of this embodiment is performed, for example, as follows. First, when performing SEM observation, the locking mechanisms 8a and 8b are released and set to the next state. The scanning needle 3 and the sample 2t are moved by the driving device 6z.
-Scan the surface of sample 2 with the electron beam at a slight distance;
Perform SBM observation while moving the field of view using the drive devices fi 6X, 6y, select the STM observation area by 8EM observation, stop driving the drive devices 6X, 6)',
Kakut! The sample 2 is gradually brought closer to the scanning needle 3 using the I device 6z. At this time, the sample and the scanning needle? Although it is necessary to avoid collisions, the operation is easy because the positional relationship between the scanning needle and the sample can be observed by continuing SEM observation. The 8TM scanning mechanism is attached to the objective lens so that the tip of the scanning needle 3 is located near the optical axis of the objective lens 1 as shown in the figure. No matter what scanning position it is in, the tip can be seen during SEX. Next, the sample stage 6 is fixed by the lock mechanisms 8a and 8b, and the relative vibration between the sample and the scanning needle is stopped. At this time, if the sample (field of view) is slightly narrow, SE
While continuing M observation, correct the field of view as necessary (by once releasing the lock mechanism and driving the sample stage), set the field of view again). After 8 TM fields of view are selected in this way and the sample stage is locked, the scanning needle can be scanned by the scanning mechanism 4 to perform STM observation. STM observation is the same as the conventional technique, so a description thereof will be omitted.

As mentioned above, since S 'l' M has a resolution of 1 Å or less, the mutual vibration between the scanning needle and the sample must be 1 Å or less during the 87M scan. However, the mutual vibration between the sample and the base of the sample coarse movement mechanism due to the sample coarse movement mechanism that moves the sample by about 1 cm to several mm becomes several tens of angstroms or more. In this embodiment, the base 7 of the sample coarse movement mechanism and the scanning needle scanning mechanism are connected by a rigid body, and during 87M scanning, the sample stage 6 is locked to the base 7 and Jai1 by the lock mechanism 8.
It is fixed to the body 5.

(G) Effects The scanning microscope of the present invention not only allows for both observation using a particle beam scanning microscope such as SEM and STM observation, but also allows for selecting any field of view for observation using a particle microscope. Observation using STM is easy and reliable, and is very convenient.

It has a compact structure, a rough movement mechanism that can move the primary sample over a wide area, and excellent vibration damping properties, making it possible to obtain high-performance STM images.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a main part of an embodiment of a scanning microscope of the present invention, and FIG. 2 is a diagram showing a main part of a scanning tunnel IV electron microscope (a diagram for explaining the prior art). 1... Objective lens of a scanning electron microscope 2. 12... Sample 3, 13... Scanning needle 4... Scanning needle scanning mechanism 14X? 14y+ 14z...Piezoelectric element 5,15
...Rigid body 6...Sample stage 7...Sample stage base 8a, 8b...Lock mechanism 9...Vibration isolation material Figure 1, Figure 2

Claims (4)

[Claims] (1) In a device that combines a particle beam scanning microscope and a scanning tunneling electron microscope to obtain a two-dimensional image of the sample surface by scanning the sample surface with a particle beam, the scanning needle scanning mechanism of the scanning tunneling electron microscope and the sample coarse movement are used. A scanning microscope characterized in that a base of the mechanism is attached to the objective lens of the particle beam scanning microscope. (2) The scanning microscope according to claim 1, further comprising a locking mechanism for fixing the movement of the sample coarse movement mechanism. (3) The scanning needle scanning mechanism and the base of the sample coarse movement mechanism of a scanning tunneling electron microscope are attached to the objective lens of a particle scanning microscope via a vibration isolating member. The scanning microscope according to item 1. (4) A scanning needle and a scanning needle scanning mechanism are attached to the objective lens of the particle beam scanning microscope so that the tip of the scanning needle of the scanning tunneling electron microscope is located near the optical axis of the objective lens of the particle beam scanning microscope. , a scanning microscope according to claim 1.