JP2012038676A - Tension and compression holder mechanism of electron microscope - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tension and compression holder mechanism of an electron microscope which can accurately detect a tensile force and in which a tensile direction does not vary in an observation of an image.SOLUTION: A tension and compression sample holder including a coarse adjustment mechanism 5 and a fine adjustment mechanism 5c is configured such that a tension axis and a tension action point or a compression axis and a compression action point are coaxially arranged, and action points of plural actuators 5 are an identical point.

Description

  The present invention relates to a tension / compression holder mechanism of an electron microscope, and more particularly to a tension / compression mechanism of an electron microscope that allows a specimen to be observed in a strain state by applying a tensile load or a compression load to the specimen. Furthermore, the present invention relates to a tension / compression mechanism of an electron microscope that can detect a tensile load or a compressive load.

  FIG. 5 is a diagram showing a conventional configuration example of the tensile test mechanism, and shows a plan view. The pulling mechanism 40 includes chuck portions 30 and 30 ′ that hold the test piece 1, and protrusions 31 and 31 ′ that engage with the holes of the test piece 1 on the upper surface. The chuck portions 30 and 30 'include the function of the sample stage portion of the electron microscope.

  Reference numerals 32 and 32 ′ denote piezoelectric element actuators for applying a tensile load to the test piece 1A via the chuck portion 30; a fine movement actuator 32 that applies ultrafine movement to the chuck portion 30; and a coarse movement actuator 32 that is moved greatly. The fine movement actuator 32 and the coarse movement actuator 32 ′ are selectively used according to the mechanical characteristics of the test piece 1A or according to the measurement purpose. That is, when measuring the test piece 1A having a high strength, the coarse movement actuator 32 'is used, and when measuring the test piece 1A having a low strength, the fine movement actuator 32 is used.

  Reference numeral 33 denotes a load cell that detects a tensile load P applied to the bridge portion of the test piece 1, and reference numeral 34 denotes an operating displacement meter. When this tensile test mechanism 40 is used, the chuck portion 30 is moved and bridged by engaging the holes of the test piece 1 with the projecting portions 31 and 31 'and operating the actuators 32 and 32'. Pull the part in the axial direction.

  As a conventional apparatus of this type, an actuator for applying a tensile or compressive load to the micro test piece on the sample stage portion of the scanning probe microscope, and means for detecting the load on the micro test piece by this There is known a technique for measuring a micro-strain of a test piece by a tensile or compression load using a sample surface observation system of a scanning probe microscope (for example, Patent Document 1). reference).

  In addition, in an electron microscope, there is known an electron microscope configured such that a sample can be moved in a three-dimensional direction with a goniometer and a sample placed on a sample stage can be pressed in a predetermined direction (see, for example, Patent Document 2).

Japanese Patent Laying-Open No. 2003-207432 (paragraphs 0010 to 0019, FIG. 1) JP 2000-315471 A (paragraphs 0019 to 0020, FIG. 1)

  If the action points of the plurality of actuators are different, a mechanism in which force is likely to be generated in an unintended direction (direction other than the pulling direction) due to the rigidity of the action points and how the moment is applied. Further, the way of installing each actuator also contributes to the pulling direction. In a transmission electron microscope that observes at a high magnification, these are observed with an angle in the moving direction (ideally 0 °) due to the difference in actuator. In extreme cases, the field of view may escape. Further, when a load is detected via the transmission shaft, a detection error is caused.

  The present invention has been made in view of such a problem, and provides a tension / compression holder mechanism of an electron microscope that can accurately detect a tension force or a compression force without changing a tension direction during image observation. The purpose is to do.

  In order to solve the above problem, the present invention has the following configuration.

  (1) The invention according to claim 1 is a tension / compression sample holder provided with a coarse motion mechanism and a fine motion mechanism, wherein the tension shaft and the tension action point, or the compression axis and the compression action point exist on the same axis, It is characterized in that the actuator has a single point of action.

  (2) The invention described in claim 2 is characterized in that a rotation / linear conversion mechanism using a motor is used as the coarse movement mechanism, and a linear movement mechanism using a piezoelectric element is used as the fine movement mechanism.

  (3) The invention described in claim 3 is characterized in that at least one lever is used between the actuator group and an action point to change the installation direction of the actuator group and change the displacement ratio. To do.

  The present invention has the following effects.

  (1) According to the invention described in claim 1, since the action points of the plurality of actuators are configured as one point, the sample can be pulled or compressed only in one axial direction at the time of pulling or compressing, The tensile force can be detected with high accuracy, and the stress of the sample due to pulling or compression can be accurately measured.

  (2) According to the invention described in claim 2, since the rotation / linear conversion mechanism of the motor is used as the coarse movement mechanism, and the linear movement mechanism using a piezoelectric element is used as the fine movement mechanism, the sample is first removed from the coarse movement mechanism. When the fine adjustment region is reached, the fine adjustment mechanism is used to pull or compress, so that the stress of the sample can be measured efficiently.

  (3) According to the invention described in claim 3, by placing at least one lever between the actuator group and the action point, the installation direction of the actuator group can be changed, and the variation ratio can be changed. Stress measurement with a wide range of applications can be performed.

It is sectional drawing of the transmission electron microscope to which this invention is applied. It is a block diagram which shows the 1st Example of this invention. It is explanatory drawing of the tension displacement by this invention. It is a block diagram which shows the 2nd Example of this invention. It is a figure which shows the example of a conventional structure of a tension test mechanism.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a sectional view of a transmission electron microscope to which the present invention is applied. In the figure, a transmission electron microscope 01 has a lens barrel 02 whose inside is kept in a vacuum, and an electron gun 03 is provided at the upper end of the lens barrel 02. A Z axis is provided along the center line of the charged particle beam emitted from the electron gun 03. At the lower end of the lens barrel 02, an observation window 04 and a fluorescent plate 05 that is movable between an observation position indicated by a solid line and a retracted position indicated by a two-dot chain line are provided.

A device for placing a film F for photographing an electron microscope image at the photographing position is disposed below the fluorescent plate 05. A focusing lens 07 for focusing the electron beam is disposed below the electron gun 03, and an imaging lens 08 for magnifying imaging is disposed above the fluorescent plate 05. A goniometer stage GS, a goniometer GM, and a sample holder H are provided between the focusing lens 07 and the imaging lens 08. The present invention relates to the sample holder H.
Example 1
FIG. 2 is a block diagram showing a first embodiment of the present invention. (A) is a perspective view, (b) is a side view. In (a), the imaginary line is a grip portion that is held by hand when the sample holder is inserted, and also serves as a cover for various actuators. The outer surface of the pipe 1a is a member with which the sample holder comes into contact with the goniometer, and a vacuum is maintained by an O-ring (not shown). The inner surface of the pipe 1a holds a pulling shaft 3a via an O-ring 2 in order to achieve a pulling mechanism while maintaining a vacuum.

  A sample clamp portion 3b is provided at the tip of the pulling shaft 3a, and a sample fixing portion 1b is provided at the tip of the pipe 1a. Reference numeral 4 denotes a sample, for example, a semiconductor chip or the like. The portion of the sample 4 where the sample clamp 3b is hooked has an elongated hole shape or the like, and a gap is provided between the sample clamp 3b and the sample 4 so that no force is applied to the sample 4.

  The pipe 1a and the base 1c are joined. On the base 1c, an actuator group 5 is provided as shown in the figure. The base 1c is fixed and does not move. At this time, there is an action point 5a of the actuator group 5 on the axial extension line of the pulling shaft 3a. The point of action is the part where force is applied. The frame 6 is always in contact with the action point 5 a by the spring 7.

  The frame 6 is connected to the pulling shaft 3 a and transmits a pulling force to the sample 4. Further, the frame 6 is held on the base 1c with a small frictional resistance by means of a slide rail (not shown). The actuator group 5 is connected to a control power source 9, and the power source 9 can be further controlled by a CPU 8. Reference numeral 10 denotes a control power supply for applying a voltage to the piezoelectric element 5 c, and receives output control from the CPU 8. A load meter may be incorporated between the pulling shaft 3a and the frame 6 as necessary. The operation of the apparatus configured as described above will be described as follows.

  The pipe 1a, the sample fixing portion 1b, and the base 1c are held by a goniometer (not shown), and the sample holder alone forms a fixing portion. On the other hand, the pulling shaft 3a and the sample clamp part 3b serve as a pulling drive part. When the action point 5a is displaced as described later, the frame 6 moves in the -X direction.

  Since the frame 6 is constantly receiving a force from the member 1 by the spring 7, the action point 5a and the frame 6 come into contact with each other. As a result, when the frame 6 moves in the -X direction, the pulling shaft 3a and the sample clamp portion 3b are pulled. It will be.

  The apparatus shown in the figure is a system composed of two actuators (motor 5 and piezoelectric element 5c). The motor 5 is used for coarse movement, and the piezoelectric element 5c is used for fine movement. In the case of motor drive, the voltage or current of the control power supply 9 is controlled by the CPU 8, and the rotation of the motor 5b is converted into linear movement by the gear 5d and the feed screw 5e. Then, the action point 5a is pushed in the −X direction with the piezoelectric element 5c as a part of the member. At this time, the voltage from the power source 10 is not applied to the piezoelectric element.

  Next, the case of driving the piezoelectric element will be described. The CPU 8 increases the voltage applied to the power source 10, applies a predetermined voltage from the power source 10 to the piezoelectric element 5 c, stretches the piezoelectric element itself, pushes the action point 5 a in the −X direction, and pulls the tension shaft 3 a The sample 4 is pulled in the −X direction through the frame 6.

  Since these finally push the action point 5a, a force is applied in the same direction, and a difference due to switching of the actuator does not occur. Since the member 3 (3a and 3b) is pulled on the axis, no moment is applied to the member 3 and the sample 4 does not rotate. Therefore, when a weight meter is configured, the accuracy of load detection is improved as compared with the prior art.

  FIG. 3 is an explanatory view of the tensile displacement according to the present invention. The horizontal axis represents the actuator signal, and the vertical axis represents the sample tensile displacement. Point K1 is a point where the pulling operation of the sample 4 by the motor is started. Thereafter, the sample displacement increases as the actuator signal increases. The driving force is switched from driving by the motor to driving the piezoelectric element at the point K2. When the piezoelectric element is further driven, the displacement of the sample 4 further increases and breaks when the point K3 is reached. When such a displacement of the sample is observed with a transmission electron microscope, the physical property of the sample 4 due to the stress can be observed.

  In the above description, the case where the sample 4 is pulled has been described, but the same applies to the case where the sample 4 is compressed.

As described above, according to the present invention, since the action points of the plurality of actuators are configured as one point, the sample can be pulled or compressed only in one axial direction at the time of pulling or compressing, and the pulling force can be accurately measured. It can be detected well, and the stress of the sample due to pulling or compression can be accurately measured.
(Example 2)
FIG. 4 is a block diagram showing a second embodiment of the present invention. The same components as those in FIG. 2 are denoted by the same reference numerals. In this embodiment, only the lever 11 is interposed between the actuator group 5 and the action point 5a, and the other configurations are the same. Although the figure shows a case where there is only one lever 11, two or more levers may be provided as necessary. Further, in the figure, an actuator portion by a motor is provided at the outermost end portion as compared with the embodiment shown in FIG. The operation of the apparatus configured as described above will be described as follows.

  By using the lever, the installation direction of the actuator group 5 can be changed, and the displacement ratio can be changed. That is, in the case of motor drive, the CPU 8 controls the voltage or current of the control power supply 9 to convert the rotation of the motor 5b into a linear motion via the gear 5d and the feed screw 5e. Then, with the piezoelectric element 5c as a part of the member, the action point 5a is pushed in the + X direction. In this embodiment, since the lever 11 is interposed, the displacement direction of the actuator 5 is opposite to the sample pulling direction.

  In the case of driving the piezoelectric element 5c, the CPU 8 depressurizes the voltage of the control power supply 9, and further applies a voltage to the control power supply 10 to stretch the piezoelectric element 5c itself and push the action point 5a in the + X direction. The spring 7 pulls the sample 4 through 3, the frame 6 and the lever 11. Since these finally push the action point 5a, a force is applied in the same direction, and a difference due to switching of the actuator 5 does not occur. Furthermore, since the member 3 is pulled on the shaft, no moment is applied to the member 3, and the accuracy of load detection can be improved even when a load meter is connected.

According to the second embodiment, since at least one lever is interposed between the actuator group and the action point, the installation direction of the actuator group can be changed and the variation ratio can be changed. Can be performed.
(Example 3)
The configuration of the third embodiment is shown in FIG. Even when the actuator group 5 comprises a plurality of motors 5b, it can be implemented. For reasons such as pulling speed, it is conceivable that different gears with different gear ratios as shown in 5d are installed. In this embodiment, 5c may be a piezoelectric element or a simple shaft. Here, the case where a shaft is used will be described.

  The gears 5d of the motor 5b are respectively arranged around the gears 5d of the pulling shaft 3a. The CPU 8 controls the voltage or current of the control power source 9 to convert the rotation of the motor 5b into linear motion via the gear 5d and the feed screw 5e. The displacement pushes the action point 5a in the −X direction via the shaft 5c.

  Since each motor finally pushes the action point 5a, a force is applied in the same direction, and a difference due to switching of the actuator does not occur. Furthermore, since the shaft of the member 3 is pulled, no force in the rotational direction is generated, and the accuracy of load detection is improved when a load meter is connected.

  In the above-described embodiment, only the case of tensile stress has been described. However, the present invention is not limited to this, and can be similarly applied to the case of compression. The only way to apply force is in the opposite direction.

  As described above in detail, according to the present invention, the following effects can be obtained.

By making the action points of a plurality of actuators one point and using a common pulling member, the following effects can be obtained.
1) Since it is not necessary to consider the difference in rigidity of the transmission member, no error occurs in the detection of tensile load.
2) Since the pulling direction is the same for both coarse and fine movements, an image is observed in one direction even in the in-situ observation of the transmission electron microscope.

DESCRIPTION OF SYMBOLS 1 Member 1a Pipe inner surface 1b Sample fixing | fixed part 1c Base 2 O ring 3 Member 3a Pulling shaft 3b Sample clamp part 4 Sample 5 Actuator 5a Action point 5b Motor 5c Piezoelectric element 5d Gear 5e Feed screw 6 Frame 7 Spring 8 CPU
9 Control power supply 10 Control power supply

Claims (3)

In tension / compression sample holders with coarse and fine movement mechanisms,
The tension shaft and the tension action point, or the compression axis and the compression action point exist on the same axis,
A tension / compression holder mechanism for an electron microscope, characterized in that the action point of a plurality of actuators is a single point.   2. A tension / compression holder mechanism for an electron microscope according to claim 1, wherein a rotation / linear conversion mechanism using a motor is used as the coarse movement mechanism, and a linear movement mechanism using a piezoelectric element is used as the fine movement mechanism. .   The electron microscope according to claim 1 or 2, wherein at least one lever is used between the actuator group and an action point to change the installation direction of the actuator group and change the displacement ratio. Pull / compression holder mechanism.

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