JPS61258162A - Ultrasonic microscope - Google Patents

Abstract

PURPOSE:To reduce the up-and-down motion of a sample which follows a mechanical scan and also to reduce power required for a scanning system by providing a groove parallel to a scanning direction on both side parts of a sample base, inserting it into two pieces of rail-shaped bearings and also supporting the sample base in the state of non-contact to the inner surface of the bearing. CONSTITUTION:A bearing part 111 is inserted from both side faces of a groove part of an H-shaped sample base 110. As for this bearing part 111, a compressed air exhaust port is provided on the upper and the lower parts and the side face, and compressed air is supplied from the intake port 112 of the compressed air. When the compressed air adjusted to a prescribed pressure is ejected from the bearing 111, the sample base 110 is supported with non-contact by air static pressure. In this way, the motion of the time of scanning of the sample base 110 becomes smooth and also, since the sample base 110 is shaped like H, a sample placing part can be taken widely and the sample of a large shape can also be attached.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an ultrasonic microscope, and particularly to an ultrasonic microscope that can scan a predetermined sample stage in a non-contact manner.

[Prior art] In recent years, it has become possible to generate and inspect ultra-high frequency sound waves up to IGHz, making it possible to realize sound wavelengths of approximately 1 μm underwater, and as a result, it has become possible to obtain high-resolution sonic imaging devices. became. That is, a concave lens is used to create a focused sound wave beam, achieving a high resolution of 1 μm.

By placing a sample in the beam and detecting the ultrasonic waves reflected by the sample, we can elucidate the elastic properties of minute regions of the sample.
Alternatively, if the sample is mechanically scanned in two dimensions and the intensity of this signal is displayed as a brightness signal on a cathode ray tube, the fine structure of the sample can be enlarged.

FIG. 1 is a diagram showing the main components of the ultrasound microscope. The focusing, transmission and reception of ultrasonic waves is performed by a spherical lens 1, and its structure consists of optically polishing one side of a material made of cylindrical fused silica, etc., and placing a piezoelectric thin film (ZnO) 2 on top of it with upper and lower electrodes 3. A pulse 5 generated from a pulse oscillator 4 is applied to the piezoelectric thin film 2 having a sandwich structure, thereby generating an ultrasonic wave 6. The other end has a diameter of 0, 1 mmφ to 1. A concave hemispherical hole of about 11φ is formed, and a medium (for example, water) 8 for propagating the ultrasonic wave 6 to the sample 7 is filled between the hemispherical hole and the sample.

Ultrasonic waves 6 generated by the piezoelectric thin film 2 propagate in the cylinder as plane waves. When this plane wave reaches the hemispherical hole, a refraction effect occurs due to the difference in sound speed between the servant (sound speed 600 m/s) and water (sound speed 1500 m/s), and the focused ultrasonic wave 6 can be irradiated onto the surface of the sample 7. can. Conversely, the ultrasonic waves reflected from the sample 7 are collected and phased by a spherical lens.
It becomes a plane wave and reaches the piezoelectric thin film 2, where it is converted into an RF signal 9. This RF signal 9 is received by a receiver 10, where it is diode-detected and converted into a video signal 11.
, is used as an input signal for the T display 12.

In the apparatus configured in this way, when the sample 7 is two-dimensionally scanned within the x-y plane by the sample stage drive power supply 13, the intensity of reflection from the sample surface as the sample scans changes two-dimensionally. displayed on surface 12.

Generally speaking, a portion of ultrasonic waves is reflected by the surface of an object, but a large portion of the ultrasound waves enters the object, regardless of whether the object is optically transparent or not. , it returns as an echo reflecting differences in viscosity and defects. Ultrasonic microscopes can utilize this property to detect aspects inside a sample.

In order to achieve high performance in the above-mentioned ultrasonic microscope*m, it is necessary to solve the following technical problems.6 The first is the creation of a spherical lens with a minute concave surface. This has the problem that when the frequency is increased to obtain high resolution, the attenuation of the ultrasonic waves increases in the medium between the spherical lens and the sample. To prevent this, we must create a micro-aperture lens and strive to shorten the distance that ultrasonic waves propagate through the medium.

The second requirement is that the vertical movement during mechanical scanning of the sample be small. The large vertical movement of the sample during scanning means that the focal plane is constantly moving, making it impossible to obtain clear images.

The third goal is to realize a piezoelectric thin film that operates stably for a long time.

Regarding the second of the above technical issues, for example, Japanese Patent Application Laid-Open No. 116058/1983 proposes a structure in which a sample stage is connected to a speaker drive coil to perform mechanical scanning. This was insufficient in terms of reducing the accompanying vertical movement. In addition, there was also the problem that the scanning system required a large amount of power. [Problems to be solved by the invention] In view of the above-mentioned drawbacks of the prior art, the present invention has been developed to reduce the An object of the present invention is to provide an ultrasonic microscope that can significantly reduce the motion and the power required for the scanning system.

[Means for Solving the Problems] The present invention has a structure in which grooves are provided on both sides of the sample stage parallel to the scanning direction, and the grooves are inserted into two rail-shaped bearings facing each other. , is characterized in that the sample stage is supported by the bearing in a non-contact state (with air interposed) between the surface of the bearing and the inner surface of the groove. In order to support the rail without contact, methods such as supplying compressed air between the inner wall of the groove and the rail, or throwing a magnet between the two and utilizing the repulsion force are used.

[Operation] According to the above configuration, the sample stage and the bearing are stably supported so as to be movable in the scanning direction (via air) in a completely non-contact manner. In addition, the sample stage has an H-shaped cross section and the overall shape is simple relative to the width of its upper surface, so it is possible to make the sample stage small and lightweight relative to the size of the sample to be mounted on the tower. Therefore, the vertical objects caused by mechanical scanning of the sample can be significantly reduced, and the driving force of the scanning system can also be small.

[Example 2] After considering how to reduce the vertical movement of the sample during scanning, we found that the sample stand had the most suitable structure for this purpose. We considered a method of scanning while supporting non-contact.

The outline will be explained using Figures 2 and 3.

Compressed air is flowed between the two bearings placed on both sides of the sample stand and the sample stand, and the sample stand is supported by this static pressure. Note that FIG. 3 is an enlarged view of the arrowed portion in FIG. 2.

Therefore, since it is a non-contact guide, there is almost no friction or frictional resistance, unlike in the case of conventionally commonly used bearing supports, and there is no wear on various parts. Furthermore, the static air layer between the table and the guide surface acts as a buffer, allowing smooth movement without being affected by slight irregularities on the guide surface or the facing surface of the sample stand.

In the figure, 100 is a guide section. In the guide part,
A compressed air outlet 101 is attached at a predetermined position, and the sample stage 103 is held by the compressed air discharged from the compressed air outlet 101. 102 is a compressed air intake port. Further, 107 is a sample stage drive shaft.

By using the sample stand configured as described above, a measurement of 0.03 μm or less above and below the sample was actually made.

Ultrasonic microscope images obtained by interferometry can be operated extremely stably.

In the above explanation, we have described the case where compressed air is used in order to make non-contact between the guide 1 surface and the guide facing surface of the sample stage.
Magnetic repulsion can also be used.

FIGS. 4 and 5 show the structure of a non-contact type sample stage using magnetic force. Note that FIG. 5 is an enlarged cross-sectional view of the arrowed portion in FIG. 4. In the figure, a north pole 105N and a south pole 105S of a magnet are provided at both ends of a guide 105, and a sample stage 106 is inserted into this guide 105. Magnets 106N and 106s are attached to the end of the sample stage 106, that is, the part facing the guide 105, and their polarities are such that their N and S poles repel the magnetic force of the guide 105. They are arranged so that they face each other. For this reason, the sample stage 106 is
05 without contact.

This situation is exactly the same as using compressed air to hold the sample stand in a non-contact manner as described in Figure 2, and the sample stand in this state is repeatedly moved back and forth periodically. By connecting with the sample stage drive shaft 107, the sample stage can be scanned.

As mentioned above, a sample stage using aerostatic pressure and magnetic force can provide a sample stage with extremely small vertical movement during scanning.

However, with the sample stage having the above-described structure, the size of the sample may be limited when placing the sample. That is, as shown in FIG.
The size of the sample 7 must be at least smaller than the part supported by the bearing part 100. If a larger sample 7 is to be placed, it is necessary to place the sample 7 in the center part of the sample stage 103 as shown in FIG. A mounting table 108 must be provided on the top surface of the mounting table 108, and the sample 7 must be placed on the top surface of the mounting table 108.

In this way, attaching the mounting stand 108 on the sample stand 103 increases the weight of the sample stand 103, and a large amount of power is required for the scanning system for scanning.

The present invention has been made in view of this point, and is designed so that the size of a sample that can be placed on a sample stage is not limited by the bearing section.

The details of one embodiment of the present invention will be described below with reference to the drawings.

FIG. 8 shows a schematic structure of the main components, and FIG. 9 shows a cross-sectional structure of the sample stage. In FIG. 9, an H-shaped sample stage 11
The bearing portion 111 is inserted from both sides of the groove portion 0.

The detailed structure of this bearing portion 111 is shown in FIG. 9, and compressed air discharge ports are provided on the upper and lower sides and on the side surface of the sample stage 110.

112 is a compressed air intake port.

In a sample stage having such a structure, when compressed air adjusted to a predetermined pressure is discharged from the bearing part 111, the sample 11
As a result of the sample table 110 being supported in a non-contact manner by aerostatic pressure, there is no difference in the smoothness of the movement of the sample table 110 during scanning from that of the sample table of the apparatus described in FIGS. 2 and 4.

Moreover, the shape of the sample stage 110 is made into an H-shape.

Since the sample mounting section can be made wide, large-sized samples can also be mounted.

As described above, according to the present invention, it is possible to significantly reduce the vertical movement associated with mechanical scanning of a sample in a mechanical scanning ultrasound microscope, and it is possible to maintain a stable relative position between the focal plane and the sample. At the same time, it is possible to achieve the effect that the driving force required for the scanning system can be small.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of an ultrasonic microscope, and FIG. 3, 4, and 5 are explanatory diagrams of the structure of the sample stage of the present invention, and FIGS. 6 and 7 are explanatory diagrams showing problems with the sample stage of FIGS. 4 and 5. 8 and 9 are structural diagrams of an embodiment of the present invention. 110... Sample stage, 111... Bearing section, 112...
Compressed air intake. 1st item 2nd item'VJ 3 圀/θθ red 6 figure/'I5 Kaya 7 figure (ti5 ￥ 8 figure tJ q figure

Claims (1)

[Claims] 1. Consisting of a sound wave propagation body and a sound wave lens formed at the end of this propagation body and having a predetermined focal point, the sample is photographed by the turbulent sound waves coming from the predetermined sample provided near the focal point. An ultrasonic microscope characterized in that the ultrasonic microscope is equipped with means for scanning the sample in a non-contact manner.