JPH07191004A - Sample holding device of ultrasonic microscope - Google Patents

Abstract

PURPOSE:To clearly recognize the internal state of a sample even at a part near the boundary between the sample and a sample stage by making the arriving time difference between reflected ultrasonic waves from the surface of the sample stage and those from the surface of the sample caused by the height difference between the surfaces of the sample stage and the sample larger than a prescribed value. CONSTITUTION:The time difference Tx between the time until the reflected signals of ultrasonic waves oscillated at a location above a sample state arrive from the upper surface of the stage and the time until the reflected signals of the waves arrive from the surface of a sample becomes about 2musec when the distance from the upper surface of the sample stage to the surface of the sample is about 1.5mm. A window width Tw of 1.33-1.5musec is set in advance in corresponding to the reflected signals of the ultrasonic waves from the surface of the sample. Therefore, no gate signal is generated even when the level of the waves is higher than an observing base point detecting level Vx at the window width Tw as shown in Fig. B', because the reflected signals from the upper surface of the sample state are positioned on the outside of the window width Tw. In addition, no plotting signal is extracted as shown in Fig. C'. Accordingly, the state of the sample near the sample stage can be clearly recognized and the state can be effectively utilized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic microscope sample holding device for holding a sample in an ultrasonic microscope.

[0002]

2. Description of the Related Art Ultrasonic microscopes are widely known in which a sample is irradiated with high-frequency sound waves and the intensity of the sound waves reflected from the sample is displayed as the density of an image. Generally, when observing the internal structure of a sample with an ultrasonic microscope, the sample is placed in a water tank held horizontally on the stage of the ultrasonic microscope, and the acoustic lens of the ultrasonic microscope is placed above the sample in the water tank. To scan the sample.

Since the acoustic lens moved in the water tank causes waves in the water in the water tank, the sample is fixed in the water tank by the sample holding device so that the waves do not move the sample in the water tank.

An example of such a sample holding device is Japanese Patent Application No.
Japanese Patent Application No. 4-73232.
The sample holding device of No. 5 holds a thin and flat sample like a so-called bonded wafer.

FIG. 1A shows a schematic plan view of this conventional sample holding device. The sample table 10 that constitutes the main body of the sample holding device has a flat, substantially square shape, and has a recess 14 in which the bonded wafer 12 is placed in the center.

The area of the recess 14 in the plane is somewhat larger than that of the bonded wafer 12, and the inner peripheral surface of the recess 14 has an orientation flat 12 of the wafer 12 placed in the recess 14.
a first linear positioning portion 14a extending along a
A linear second positioning portion 14b extending in a direction substantially orthogonal to the first positioning portion 14a;
And an arc-shaped portion 14c extending between the outer ends of the second positioning portions 14a and 14b along the arc-shaped portion of the peripheral surface of the bonded wafer 12 in the recess 14.

A through hole 14d having a diameter smaller than that of the bonded wafer 12 is formed in the center of the recess 14, and a part 14d 'of the through hole 14d communicates with the recess 14 and is radially outward. It extends to one direction.

The through hole 14d and a portion 14d 'thereof are placed on the bonded wafer 12 in the recess 14 or the recess 14
It is designed for a wafer-holding handle of a machine (not shown) that is used for removal from the machine.

First and second positioning portions 14a, 14
A portion 14c 'of the arcuate portion 14c is also enlarged radially outward of the arcuate portion 14c on the inner peripheral surface of the recess 14 facing the intersection region of b, and the part 14c of the arcuate portion 14c is expanded.
A pressing means 16 for selectively pressing the peripheral surface of the bonded wafer 12 in the recess 14 is arranged in the radially enlarged portion of the bottom surface of the recess 14 surrounded by c ′.

The pressing means 16 is the bonded wafer 12
The pressing member 18 that is adjacent to the peripheral surface and extends along the peripheral surface.
And a cam 20 disposed on the opposite side of the pressing member 18 from the bonded wafer 12, and a detent 22 adjacent to the cam 20.

One end of the pressing member 18 is a rotation center shaft 18a.
Is rotatably attached to the radially expanded portion of the bottom surface of the recess 14, and a pressing protrusion 18b is formed on the side of the pressing member 18 adjacent to the peripheral surface of the bonded wafer 12, and further adjacent to the cam 20. On the side of the pressing member 18, a leaf spring 18c is created by a slot formed along this side.

The cam 20 is provided with a recess 1 by a rotation center shaft 20a.
It is rotatably attached to the radially enlarged portion of the bottom surface of the No. 4.

As shown in FIG. 1A, when the cam 20 is not pressed by the leaf spring 18c of the pressing member 18, the pressing protrusion 18b of the pressing member 18 is retracted into the arc-shaped portion 14c of the inner peripheral surface of the recess 14. The work of attaching / detaching the bonded wafer 12 to / from the recess 14 is allowed.

Bonded wafer 12 to recess 14
As shown in FIG. 1A, the orientation flat 12a is formed in the recess 1
4 is placed in a state of facing the first positioning portion 14a on the inner peripheral surface of No. 4.

When the cam 20 is rotated until it comes into contact with the detent 22 as shown in FIG. 1B, the cam 20 presses the plate spring 18c of the pressing member 18, which causes the pressing member 18 to plate. The pressing protrusion 18b is generated by the urging force of the spring 18c.
Are pressed against the peripheral surface of the bonded wafer 12.

The bonded wafer 12 pressed by the pressing member 18 has an orientation flat 12a as shown in FIG.
Are abutted on the opposing first positioning portion 14a and a portion of the peripheral surface opposing the second positioning portion 14b are abutted, so that the recess 14 is fixed at a predetermined position.

The pressing projection 18b of the pressing member 18 presses the peripheral surface of the bonded wafer 12 by the urging force of the leaf spring 18c of the pressing member 18, so that the bonded wafer 12 is excessively pressed from the pressing member 18. Since no force is applied, the bonded wafer 12 is prevented from being damaged.

The surfaces of the first and second positioning portions 14a and 14b that abut the bonded wafer 12 and the pressing protrusion 18b of the pressing member 18 are formed in the recess 14 as shown in FIG. 1C. The diameter is increased so as to approach the bottom surface, and the bonded wafer 12 is prevented from dropping from the recess 14 when the sample table 10 is tilted.

The sample holding device to which the bonded wafer 12 is fixed as described above is detachably fixed to a predetermined position in a water tank held on the stage of an ultrasonic microscope, and ultrasonic waves are applied to a predetermined height above the ultrasonic wave. The internal structure is observed by moving the acoustic lens of the microscope according to a predetermined pattern.

The ultrasonic microscope is used for observing whether or not a cavity is formed at the interface (bonding surface) in the internal structure of the bonded wafer 12.

Now, the acoustic lens of the ultrasonic microscope has a predetermined height above the bonded wafer 12 held by the sample holding device which is detachably fixed at a predetermined position in the water tank of the ultrasonic microscope. The ultrasonic reflection signal detected at a certain coordinate position on the bonded wafer 12 when moving in a pattern is as shown in FIG.

In FIG. 2A, the first detected large level wave corresponds to the surface (upper surface) of the bonded wafer 12, and the next detected larger level wave is inside the bonded wafer 12. Corresponding to the interface, the third level of the detected high-level wave corresponds to the back surface (bottom surface) of the bonded wafer 12.

The control circuit of the ultrasonic microscope detects the inside of the bonded wafer 12 from the ultrasonic reflected signals as shown in FIG. 2A detected at each of a number of predetermined coordinate positions on the bonded wafer 12. Only the wave corresponding to the interface of the wafer is extracted as the drawing signal, and based on this, the bonded wafer 12
The state of the interface inside the is displayed on the display device over almost the entire area.

For the above extraction, the control circuit of the ultrasonic microscope detects an ultrasonic wave reflected signal from the surface of the bonded wafer 12 after the ultrasonic wave is generated from the acoustic lens, as shown in FIG. 2 (A). The ultrasonic reflection signal detection time width (window width Tw) having a predetermined time width is set around the estimated time, and the ultrasonic reflection signal from the surface of the bonded wafer 12 is set at a level higher than the expected maximum level. A slightly lower observation base point detection level Vx is set.

Furthermore, the bonded wafer 12 detected after a predetermined delay time Td has elapsed after the level of the ultrasonic reflection signal from the surface of the bonded wafer 12 detected at the window width Tw exceeds the observation reference point detection level Vx. The generation time width of the gate signal and the predetermined delay time Td for extracting only the ultrasonic reflection signal from the internal interface of the as a drawing signal are set.

That is, the acoustic lens of the ultrasonic microscope has a predetermined height above the bonded wafer 12 held by the sample holding device detachably fixed to a predetermined position in the water tank of the ultrasonic microscope. When moving in a pattern, the ultrasonic reflection signal detected at a certain coordinate position on the bonded wafer 12 causes ultrasonic reflection from the internal interface of the bonded wafer 12 at the certain coordinate position as follows. The signal is extracted as a drawing signal.

First, after a predetermined delay time Td elapses from the time when the level of the ultrasonic reflection signal from the surface of the bonded wafer 12 detected at the window width Tw exceeds the observation reference point detection level Vx. A gate signal having a predetermined time width set in advance is generated, and an ultrasonic wave reflection signal from the internal interface of the bonded wafer 12 detected during the generation of the gate signal is extracted as a drawing signal.

Here, by setting the window width Tw with the observation reference point detection level Vx, the delay time Td, and the gate signal with a predetermined time width as described above, the predetermined depth width inside the bonded wafer 12 is always maintained. Since the ultrasonic wave reflection signal from the region can be extracted as a drawing signal, even if the bonded wafer 12 held by the sample holding device at a predetermined position in the water tank is slightly inclined from the horizontal plane, Includes the entire interface inside the bonded wafer 12 that is slightly inclined, and after all, the state of the entire interface inside the bonded wafer 12 that is slightly inclined can be displayed on the display device over substantially the entire area.

[0029]

[Problems to be Solved by the Invention] Japanese Patent Application No. 4-72325
No. 4 sample holder, 4 inches in diameter and 1 m thick
In the case of holding the bonded wafer of m, the depth D of the recess 14 of the sample table 10 shown in FIG.
The height difference between the upper surface of the sample table 10 and the upper surface of the bonded wafer 12 in the recess 14 is set to about 0.5 mm.

When observing the entire area inside the bonded wafer 12 having a diameter of 4 inches, the scanning width of the acoustic lens (field width of the ultrasonic microscope) is about 100 mm, and here the tilt of the bonded wafer 12 is obtained. If the allowable value of is about 1 mm, the window width Tw is 1.33 μsec.
It is set to ˜1.5 μsec.

Since the scanning width of the acoustic lens also includes the upper surface of the sample table 10, when the acoustic lens starts scanning, the reflection signals of ultrasonic signals from the upper surface and the lower surface of the sample table 10 within the scanning area. Will also be included.

FIG. 3 (A ') shows an ultrasonic reflection signal detected at a position shown by an arrow A'above the upper surface of the sample table 10, where the first large level wave is The upper surface of the sample table 10 and the second higher level wave correspond to the lower surface of the sample table 10.

On the other hand, the sample table 10 is shown in FIG.
The ultrasonic reflection signal detected at the position indicated by arrow A above the upper surface of the bonded wafer 12 in the recess 14 is shown, where the first large reflected signal level is the upper surface of the bonded wafer 12. In addition, the second large reflected signal level corresponds to the internal interface of the bonded wafer 12, and the third large reflected signal level corresponds to the back surface of the bonded wafer 12.

The time difference Tx between the wave of the ultrasonic signal corresponding to the upper surface of the sample table 10 in FIG. 3A 'and the wave of the ultrasonic signal corresponding to the upper surface of the bonded wafer 12 in FIG. 3A.
Is about 0.67μ because the sound velocity in water is 1500m / sec
sec, and the bonded wafer 12 shown in FIG.
Window width Tw (1.33 μsec to 1.5 μs) preset corresponding to the wave of the ultrasonic signal corresponding to the upper surface of the
Waves of ultrasonic signals corresponding to the upper surface of the sample table 10 in FIG. 3A 'are also included in ec).

Therefore, the ultrasonic signal corresponding to the upper surface of the sample table 10 of FIG. 3A ′ detected at the position shown by the arrow A ′ of FIG. 1C above the upper surface of the sample table 10. Of the gate signal of the predetermined time width after the passage of the predetermined delay time Td from the time when the wave exceeds the preset observation base point detection level Vx in the window width Tw. 3B ', the ultrasonic reflection signal from the inside of the sample stage 10 detected during the generation of the gate signal is extracted as a drawing signal as shown in FIG. 3C'.

As a matter of course, the upper surface of the bonded wafer 12 corresponds to the upper surface of the bonded wafer 12 of FIG. 3A detected at the position indicated by the arrow A of FIG. 1C. A predetermined delay time Td set in advance from the time when the wave of the ultrasonic signal exceeds the preset observation base point detection level Vx in the window width Tw.
3B, a gate signal having a preset time width is generated as shown in FIG. 3B, and the ultrasonic reflection signal from the inside of the sample stage 10 detected during the generation of the gate signal is It is extracted as a drawing signal as shown in FIG.

As described above, in the conventional sample holding device, when observing the entire area inside the bonded wafer 12, the ultrasonic reflection signal indicating the internal state of the sample table 10 is scanned while scanning the upper surface of the sample table 10. Since the drawing signal based on this is also extracted, in the vicinity of the boundary between the upper surface of the bonded wafer 12 and the upper surface of the sample stand 10 (first and second positioning portions 14a and 14b in FIG. 3B), the sample stand The boundary between the drawing signal indicating the internal state of 10 and the drawing signal indicating the state of the interface inside the bonded wafer 12 becomes unclear, and the state of the interface inside the bonded wafer 12 near the above becomes unclear. .

This makes it difficult to use the area of the bonded wafer 12 in the vicinity thereof and reduces the utilization efficiency of the expensive bonded wafer 12.

Further, in the conventional ultrasonic microscope, the center of the sample on the sample holding device as the reference position for starting scanning for observing the sample is set at the acoustic lens of the ultrasonic microscope every time the sample holding device or the type of the sample changes. The operator of the ultrasonic microscope manually performs the work of aligning with the action center of the above, and this work is complicated.

The present invention has been made based on the above circumstances, and an object of the present invention is to obtain a desired depth inside the sample even near the boundary between the upper surface of the sample placed at a predetermined position on the sample table and the upper surface of the sample table. It is possible to clearly know the state of the large area, and to obtain an easy-to-see image without unnecessary noise in the area outside the sample. Also, an ultrasonic microscope sample holding device that can automatically perform the work of aligning the working center of the acoustic lens of the ultrasonic microscope with the center of the sample on the sample holding device as the scanning start position when the sample holding device is set Is to provide.

[0041]

In order to achieve the former object of the present invention described above, an ultrasonic microscope sample holding device according to the present invention has a predetermined time set after a predetermined time has elapsed after ultrasonic oscillation. The ultrasonic wave reflection signal detected while the gate signal is being emitted by issuing the gate signal of the predetermined time width after the elapse of the predetermined delay time after detecting the ultrasonic wave reflection signal above the predetermined reference detection level in the width window. A sample holding device used for holding a sample in an ultrasonic microscope for extracting as a drawing signal, the sample holding device having a sample stage formed with a recess in which the sample is placed, and a surface of the sample stage. It is characterized in that the time difference of the reflected ultrasonic waves from each position due to the difference from the height of the sample placed in the recess is set to be larger than the predetermined time width of the window.

In order to achieve the latter object of the present invention described above, another ultrasonic microscope sample holding device according to the present invention is: a sample holding table on which a sample is detachably held; A stage that is placed on the stage and is movable within a predetermined range in a substantially horizontal plane; a sample holder positioning means that is provided on the stage and that detachably fixes the sample holder to a predetermined position on the stage; And a stage movement control means for controlling the movement of the stage after being removably fixed to a predetermined position on the stage by the sample holding table positioning means so that the acoustic lens matches the scanning start position of the sample. Is characterized by.

In order to achieve the latter object of the present invention described above, still another ultrasonic microscope sample holding device according to the present invention is: a sample holding table on which a sample is detachably held;
A stage on which the sample holder is placed; an acoustic lens which is provided above the stage and is movable in a substantially horizontal plane along the sample surface on the sample holder; Acoustic lens movement control means for controlling the movement of the acoustic lens after being removably fixed to the above predetermined position so as to match the acoustic lens with the scanning start position of the sample.

[0044]

The ultrasonic microscope sample holding device according to the present invention for attaining the former object of the present invention described above has an acoustic lens of an ultrasonic microscope which has a predetermined scanning region including a sample stage on which a sample is placed. Among the ultrasonic wave reflection signals obtained by scanning, the ultrasonic wave reflection signals corresponding to the surface of the sample stage are generated outside the window of the predetermined time width and do not generate a gate signal. The ultrasonic reflection signal indicating the state of the predetermined depth region inside the sample stage is not extracted as the drawing signal.

Only the ultrasonic reflected signal corresponding to the surface of the sample is detected in the window, and the predetermined delay after the ultrasonic reflected signal corresponding to the surface of the sample exceeds a predetermined reference detection level in the window. After a lapse of time, a gate signal having a predetermined time width is emitted, and the ultrasonic reflection signal detected while the gate signal is being emitted is extracted as a drawing signal indicating the state of a predetermined depth position inside the sample.

In the ultrasonic microscope sample holding device according to the present invention for achieving the latter object of the present invention described above,
When the sample holder that holds the sample detachably is placed on the stage and fixed at a predetermined position on the stage by the sample holder positioning means, the movement of the stage or the acoustic lens is controlled to attach and detach the sample holder. The desired position of the freely held sample is matched with the scanning start position of the acoustic lens.

[0047]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will now be described with reference to FIG.
It will be described with reference to FIGS.

The structure of the ultrasonic microscope sample holder of this embodiment is the same as the structure of the conventional ultrasonic microscope sample holder shown in FIGS. 1A, 1B and 1C, The depth D of the recess 14 is set to about 2.5 mm, and the difference between the surface of the sample and the thickness of the bonded wafer 12 placed in the recess 14 of about 1.0 mm is about 1.5 mm. Has become.

In this case, the ultrasonic reflection signal obtained when the sample table 10 is observed by the acoustic lens at the position shown by the arrow A'in FIG. 1C is shown in FIG. The wave of the first large level corresponds to the front surface (upper surface) of the sample table 10, and the wave of the second larger level corresponds to the rear surface (lower surface) of the sample table 10.

Further, an ultrasonic reflection signal obtained when the bonded wafer 12 placed in the recess 14 of the sample table 10 at the position shown by the arrow A in FIG. As shown in FIG. 4A, the first large level wave corresponds to the surface (upper surface) of the bonded wafer 12, and the second largest level wave is at the interface inside the bonded wafer 12. Correspondingly, the wave of the third largest level is the back surface (bottom surface) of the bonded wafer 12.
It corresponds to.

In this embodiment, the time from when the ultrasonic wave is oscillated from the acoustic lens which is separated by a predetermined distance above the sample table 10 until the ultrasonic reflected signal corresponding to the surface (upper surface) of the sample table 10 is obtained. The difference Tx from the time until the ultrasonic reflection signal corresponding to the surface (upper surface) of the bonded wafer 12 is obtained is the distance from the surface (upper surface) of the sample table 10 to the surface (upper surface) of the bonded wafer 12 (that is, , Sample table 10
The difference between the depth D of the recess 14 of approximately 2.5 mm and the thickness of the bonded wafer 12 placed in the recess 14 of approximately 1.0 mm) is approximately 1.5 mm in the water tank on the stage of the ultrasonic microscope. Ultrasonic waves oscillated from the acoustic lens at a sound velocity of 1500 m /
The time required to make a round trip in sec is about 2 μsec.

As described above, the window width Tw preset corresponding to the wave of the ultrasonic signal corresponding to the upper surface of the bonded wafer 12 shown in FIG. 4A is 1.33 μsec.
Since it is 1.5 μsec, the ultrasonic reflection signal corresponding to the surface (upper surface) of the sample table 10 is located outside the window width Tw as shown in FIGS. 4A and 4A. Therefore, even if the wave level of the ultrasonic signal corresponding to the surface of the sample table is higher than the observation base point detection level Vx in the window width Tw, the gate signal is not generated as shown in FIG. However, from the ultrasonic reflection signal shown in FIG. 4A ′ obtained when the sample stage 10 is observed by the acoustic lens at the position shown by the arrow A ′ in FIG. As shown in (C '), no drawing signal is obtained.

In FIG. 4B, a predetermined delay time Td elapses after the level of the ultrasonic reflection signal from the surface of the bonded wafer 12 detected at the window width Tw exceeds the observation reference point detection level Vx. After that, a state in which a gate signal having a predetermined time width is transmitted is shown in FIG.
In (C), a drawing signal extracted based on the ultrasonic reflection signal from the internal interface of the bonded wafer 12 detected during the generation of the gate signal is shown.

As described above, in the sample holding apparatus according to the embodiment of the present invention, when observing the entire area inside the bonded wafer 12, the inside of the sample table 10 is observed while scanning the upper surface of the sample table 10. The drawing signal based on the sound wave reflection signal is not extracted. Therefore, the bonded wafer 12
Even in the vicinity of the boundary between the upper surface of the wafer and the upper surface of the sample table 10 (first and second positioning portions 14a and 14b in FIG. 3B), only the drawing signal indicating the state of the interface inside the bonded wafer 12 is generated. It is possible to clearly display the state of the interface that is extracted and inside the bonded wafer 12 in the vicinity of the above.

This makes it possible to use the area of the bonded wafer 12 in the vicinity of the above, and improves the utilization efficiency of the expensive bonded wafer 12.

Furthermore, since the drawing signal is "zero level" on the surface of the sample table in the area where there is no wafer, the image is easy to see without unnecessary noise.

In the embodiment described above, the difference between the depth D of the recess 14 of the sample table 10 and the thickness of the bonded wafer 12 placed in the recess 14 is about 1.5 mm. According to the summary of the above, the difference is that the bonded wafer 1
The time until the ultrasonic reflection signal corresponding to the surface (upper surface) of the sample stage 10 is located on the near side of the window width Tw preset corresponding to the ultrasonic reflection signal corresponding to the second surface (upper surface). The ultrasonic reflection signal corresponding to the surface (upper surface) of the sample table 10 is set to the window width Tw.
It doesn't have to be located inside.

FIG. 5 schematically shows an ultrasonic microscope sample holding device according to another embodiment of the present invention.

This ultrasonic microscope sample holding apparatus comprises a sample holding table 30 on which a sample is detachably held and a sample holding table 3
An electric stage 32, on which 0 is mounted and is movable within a predetermined range in a substantially horizontal plane, is provided.

The electric stage 32 has a fixed pedestal 32a placed on the floor or a desk, a first movable pedestal 32b movable in the X-axis direction on the fixed pedestal 32a, and a Y movable on the first movable pedestal 32b. A second movable pedestal 32c that is movable in the axial direction
And a water tank 32d supported on the second moving base 32c
And are equipped with.

Each of the first moving pedestal 32b and the second moving pedestal 32c is moved in the X-axis direction or the Y-axis direction by a combination of a pulse motor (not shown) and a feed screw to move the water tank 32d in the XY directions. To the sample holder 3
The sample on 0 is scanned two-dimensionally.

The sample holder 30 shown in FIG. 1 can be used as the sample holder 30, and the sample holder 30 is shown at a predetermined position on the bottom surface of the water tank 32d on the second moving base 32c of the stage 32. Not fixed by the sample holder positioning means.

In this embodiment, the sample holding table positioning means is composed of a positioning pin installed at a predetermined position on the bottom surface of the water tank 32d and a positioning pin insertion hole formed at a predetermined position of the sample holding table 30. There is.

FIG. 5 shows the sample holder 30 in the water tank 32d.
Also shown is an acoustic lens support frame 36 supporting an acoustic lens 34 spaced a predetermined distance above a desired position (e.g., center) of the sample held at. The acoustic lens support frame 36 includes an acoustic lens scanning unit 38 which causes the acoustic lens 34 to vibrate at a high speed in, for example, the X direction in a predetermined substantially horizontal small area, and vertically moves.

In order to observe the sample held on the sample holder 30 in the ultrasonic microscope, first, the sample is detachably fixed to the sample holder 30 outside the water tank 32d, and then a sample set switch (not shown) is used. When pressed, the electric stage 32 is driven by a stage control unit (not shown), and the water tank 32d is moved obliquely downward to the right so that the sample holder 30 is retracted from the position of the acoustic lens 34, as shown in FIG. To be In this state, the sample holder 30 that detachably holds the sample 30a is detachably fixed to a predetermined position in the approximate center of the water tank 32d by the above-described sample holder positioning means (positioning pin 40a and positioning pin insertion hole 40b). To be done.

Then, by pressing a sample set confirmation switch (not shown), the electric stage 32 starts to operate, and as shown in FIG. 6B, the desired position of the sample held on the sample holder 30 (normally The water tank 32d is moved diagonally upward to the left so that its (approximately its center) coincides with the optical axis of the acoustic lens 34.

In this initial position setting operation, the stage controller (not shown) stores the sample position on the sample holder 30 in advance, so that the operator simply presses the sample set confirmation switch to set the position of the acoustic lens 34 in advance. The motorized stage 32 is automatically driven and controlled so that the stored sample positions match.

Then, by turning on a scanning start switch (not shown) of the ultrasonic microscope, the moving pedestals 32a, 32
As b moves in the XY directions, the acoustic lens 34 starts scanning in a predetermined area on the sample in a predetermined scanning pattern.

After that, the entire sample held on the sample holder 30 is observed by ultrasonic waves, and a drawing signal showing only the state of the internal interface of the entire sample is observed as described in the above embodiment. It is extracted and clearly displayed on a display device (not shown).

In this embodiment, the sample holder 30 is attached to the water tank 3.
The water tank 32d so that the mounting position of the sample holder 30 is retracted from the position of the acoustic lens 34 when set to 2d.
Since the (movable pedestals 32a, 32b) are automatically moved, the sample holding table 30 can be easily replaced, and when the setting of the sample holding table 30 is completed, the electric stage 32 is driven by the stage controller (not shown). Since the water tank 32d is automatically restored, it is not necessary to manually perform the matching work each time the sample holder 30 is replaced.

Further, in this embodiment, the matching work is performed in advance for a combination of a plurality of types of sample holders 30 and a plurality of types of samples, and the first and second movable pedestals 32b and 32c in each combination at that time are matched. If the respective coordinate positions are stored in the stage movement control means (not shown) of the first and second moving pedestals 32b and 32c, the above-mentioned combination is changed and a new position is added to a predetermined position substantially in the center of the water tank 32d. When the sample holder 30 is installed, one corresponding to the new combination installed is selected from the various selection switches determined in advance corresponding to the various combinations, and then operated. When a scan start switch (not shown) is turned on, the matching work for a new combination is not shown in the figure without manually performing the matching work. Performed by the stage movement control unit, followed by the entire scan of the sample held by the sample holder 30 and the sample holder 30 of the new combination is performed.

In the above-mentioned embodiment, the water tank 32d on which the sample holder 30 is placed is moved to select the field of view. On the contrary, by fixing the water tank and moving the acoustic lens with respect to the water tank. Also, the same effect as that of the above-described embodiment can be obtained.

FIG. 7 schematically shows such an arrangement. In FIG. 7, the water tank 50 in which the sample holder positioning means (positioning pin 40a and positioning pin insertion hole 40b) as shown in FIG. 6 is installed at a substantially central position is driven by a Z-axis motor 52 via a timing belt 54. Vertical direction (Z-axis direction) by the lead screw 56
Is movably supported at the desired position.

An acoustic lens support beam 51 extending substantially horizontally in the left-right direction of the water tank 50 is bridged over the water tank 50, and the left and right ends of the acoustic lens support beam 51 are arranged on both sides of the water tank 50 in the front-rear direction. The ball screw 58 and the guide rod 60 extending substantially horizontally in the direction are screwed and inserted. The acoustic lens support beam 51 can be moved to a desired position in the front-rear direction (Y-axis direction) on the water tank 50 by rotating the ball screw 58 in one direction or the other direction by the Y-axis motor 62.

The acoustic lens support beam 51 has a ball screw 6 extending in the left-right direction (X-axis direction) which is orthogonal to the front-rear direction (Y-axis direction) which is the moving direction of the acoustic lens support beam 51.
4 is rotatably supported, and an acoustic lens 66 is screwed onto the ball screw 64.

The acoustic lens 66 can be moved to a desired position in the left-right direction (X-axis direction) on the water tank 50 by rotating the ball screw 64 in one direction or the other direction by the X-axis motor 68.

With this configuration, when the sample holder 30 is attached to or detached from the sample holder positioning means in the water tank 50,
When a sample set switch (not shown) is pressed, the acoustic lens support beam 51 is moved to the rear end of its front-rear direction movement range by a stage control section (not shown), and the acoustic lens 66 is moved to either the left-right direction movement range on the ball screw 64. By being moved to one end, the above attachment / detachment is facilitated.

The sample holder 30 is used as the sample holder positioning means.
When a sample set confirmation switch (not shown) is pressed after the is set, the acoustic lens support beam 51 is moved to approximately the center of its front-rear movement range, and the acoustic lens 66 is further moved in the left-right movement range on the ball screw 64. By moving to the center, the observation center is matched with the preset desired position of the sample on the sample holder 30 of the sample holder positioning means in the water tank 50.

Further, instead of pressing the sample set confirmation switch, an openable cover for covering the stage is attached, the open / closed state is detected by a sensor, and the stage is moved when it is detected that the cover is closed. You can also do it.

After moving the stage to set the acoustic lens at the center of the sample, the autofocus mechanism is operated to automatically adjust the focus to a desired position.
After that, it is possible to observe the sample according to the field frame set in advance.

When a plurality of samples can be held at one time by the sample holding device, the observation center position of the acoustic lens is sequentially aligned with a desired position of each sample and scanning is started to reflect ultrasonic waves of each sample. If you program a series of operations to take a signal image and save the data in an external storage device such as a hard disk or a magneto-optical disk,
After setting the sample holding device, the operator does not need to operate at all until the observation of all the samples on the sample holding device is completed, and it is possible to obtain the effect that another work can be performed during this .

[0082]

As described in detail above, in the ultrasonic microscope sample holding device according to the present invention, the sample is held even near the boundary between the upper surface of the sample placed at a predetermined position on the sample table and the upper surface of the sample table. The state of the desired depth region inside can be clearly known, and an easy-to-see image without unnecessary noise can be obtained in the region outside the sample. Further, it is possible to automatically perform the work of aligning the working center of the acoustic lens of the ultrasonic microscope with the center of the sample on the sample holding device as the scanning start reference position when the sample holding device is set.

[Brief description of drawings]

FIG. 1A shows a conventional ultrasonic microscope sample holding device having the same size and structure as the ultrasonic microscope sample holding device according to the embodiment of the present invention except for a part of the dimensions in a sample released state. FIG. 4B is a plan view showing the ultrasonic microscope sample holding device of FIG.
(C) is a longitudinal sectional view taken along the line CC of (B).

FIG. 2 is a drawing signal for displaying only an ultrasonic reflection signal corresponding to the interface when an ultrasonic microscope is used to observe the state of the interface inside the bonded wafer as a sample. It is a figure which shows the process to extract.

FIG. 3 is a diagram showing an example of holding an ultrasonic microscope sample when an ultrasonic microscope is used to observe a state of an interface inside a bonded wafer as a sample held by the conventional ultrasonic microscope sample holding device of FIG. It is a figure which shows the process in which the process of extracting as a drawing signal for displaying only the ultrasonic reflection signal corresponding to the said interface on a display means by the ultrasonic reflection signal corresponding to the upper surface of the sample stand of an apparatus.

4 shows a case where an ultrasonic microscope is used to observe the state of an interface inside a bonded wafer as a sample held by the ultrasonic microscope sample holding device of FIG. 1 according to an embodiment of the present invention. , A step of not interfering with the step of extracting as a drawing signal for displaying only the ultrasonic reflection signal corresponding to the above interface on the display means by the ultrasonic reflection signal corresponding to the upper surface of the sample stage of the ultrasonic microscope sample holding device It is a figure.

FIG. 5 is a diagram schematically showing an appearance of an ultrasonic microscope sample holding device according to another embodiment of the present invention.

FIG. 6 schematically shows a step of aligning a desired position of a sample detachably fixed at a predetermined position by the ultrasonic microscope sample holding device of FIG. 5 with a scanning start initial position of an acoustic lens of the ultrasonic microscope. It is a figure.

FIG. 7 is a diagram schematically showing an external appearance of an ultrasonic microscope sample holding device according to yet another embodiment of the present invention.

[Explanation of symbols]

10 ... Sample stand, 12 ... Bonded wafer (sample), 1
2a ... Orifla, 14 ... Recess, 14a ... 1st positioning part, 14b ... 2nd positioning part, 14c ... Arc part, 14c '... Part, 14d ... Through hole, 14d' ... Part, 16 ... Pressing Means, 18 ... Pressing member, 18a ... Rotation center axis, 18b ... Pressing protrusion, 18c ... Leaf spring, 20 ... Cam, 20a ... Rotation center axis, 22 ... Rotation stop, 30 ... Sample holder, 32 ... Stage, 32a ... Fixed base, 32b ...
1st movable pedestal, 32c ... 2nd movable pedestal, 32d ... Water tank, 34 ... Acoustic lens, 36 ... Acoustic lens support frame, 38 ... Acoustic lens scanning part, 40a ... Positioning pin,
40b ... Locating pin insertion hole, 50 ... Water tank, 52 ... Z-axis motor, 54 ... Timing belt, 56 ... Lead screw, 58 ... Ball screw, 60 ... Guide rod, 62 ... Y-axis motor, 64 ... Ball screw, 66 ... Acoustic lens, 68 ...
X-axis motor.

Claims (4)

[Claims] 1. A gate having a predetermined time width after a lapse of a predetermined delay time after detecting an ultrasonic reflection signal having a predetermined reference detection level or higher in a window having a predetermined time width set after a predetermined time has elapsed after ultrasonic oscillation. A sample holding device used to hold a sample in an ultrasonic microscope that emits a signal and extracts the ultrasonic reflection signal detected while the gate signal is being emitted as a drawing signal. It is equipped with a sample table with a recess formed in it, and the time difference of the reflected ultrasonic waves from each point due to the difference between the surface of the sample table and the height of the sample placed in the above-mentioned recess is the predetermined time of the above window. An ultrasonic microscope sample holding device, which is set to be larger than the width. 2. The ultrasonic microscope sample holder according to claim 1, wherein the difference between the surface of the sample table and the height of the sample placed in the recess is about 1.5 mm or more. apparatus. 3. A sample holding table on which a sample is detachably held; a stage on which the sample holding table is placed and which is movable within a predetermined range in a substantially horizontal plane; and a sample holding table provided on the stage. A sample holding table positioning means for detachably fixing the sample holding table to a predetermined position on the stage; and a movement of the stage is controlled after the sample holding table is detachably fixed to the predetermined position on the stage by the sample holding table positioning means. And a stage movement control means for aligning the acoustic lens with the scanning start position of the sample; 4. A sample holding table on which a sample is detachably held; a stage on which the sample holding table is mounted; provided above the stage and along a sample surface on the sample holding table within a substantially horizontal plane. A movable acoustic lens; after the sample holder is detachably fixed to a predetermined position on the stage by the sample holder positioning means, the movement of the acoustic lens is controlled so that the acoustic lens matches the scanning start position of the sample. An acoustic microscope sample holding device comprising: