JP2001028250A - High voltage introducing mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent damages to a high voltage cable for applying high voltage to a target and to prevent lowering of target movement accuracy. SOLUTION: An X-axis rail 24A, whereon a projecting part is formed along a longitudinal direction, is fixed on a stage base 21, another rail 24B whereon a recessed groove is formed along a longitudinal direction is fixed on an X- direction stage 22, the projecting part of the rail 24A is fitted into the recessed groove of the rail 24B, and the rail 24A is constituted so as to slide relative to the rail 24B by movement of the X-direction stage 22. One Y-rail 25A whereon a projecting part is formed along a longitudinal direction is fixed on the X-direction stage 22, another rail 25B whereon a recessed groove is formed along a longitudinal direction is fixed on a Y-direction stage 23, the projecting part of the rail 25A is fitted into the recessed groove of the rail 25B, and the rail 25A is constituted, so as to slide relative to the rail 25B by movement of the Y-direction stage 23.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high voltage introducing mechanism configured to apply a high voltage to a target.

[0002]

2. Description of the Related Art In many cases, a high voltage is applied to a target. For example, a scanning electron microscope will be described as an example.

FIG. 1 schematically shows a scanning electron microscope. In FIG. 1, reference numeral 1 denotes a scanning electron microscope column maintained at a high vacuum.
2 is an electron gun for generating an electron beam, 3 and 4
A focusing lens and an objective lens for focusing and narrowing the electron beam. Reference numeral 5 denotes a scanning coil for two-dimensionally scanning a target (a sample in the case of a scanning electron microscope) 6 with an electron beam. Reference numeral 7 denotes a sample chamber kept in a high vacuum, and a sample stage 8 is installed in the sample chamber. The sample stage 8 can be freely moved in the X and Y directions by a stage driving mechanism (not shown). As a result, a desired position on the sample 6 placed on the sample stage 8 is obtained. Can be observed with a microscope. The sample 6 is loaded from outside the sample chamber into the sample chamber via an air lock chamber (not shown), and is mounted on the sample stage 8. Reference numeral 9 denotes a detector for detecting secondary electrons generated from the sample by the irradiation of the electron beam.

Although not shown, the scanning electron microscope further includes an electric circuit for controlling the electron gun 2, the lenses 3, 4, the scanning coil 5, the sample stage 8, etc., and a detector 9. There is provided an electric circuit for amplifying the above signal, a CRT for displaying an electron microscope image using the signal, and the like. In such a scanning electron microscope, the electron beam generated by the electron gun 2 is narrowed down by the converging lens 3 and the objective lens 4 and irradiated onto the sample 6, and the scanning coil 5 scans the sample 6 two-dimensionally. I do. Secondary electrons generated by the scanning are detected by the detector 9 and displayed on a CRT (not shown) as a scanning microscope image. By the way, in such a scanning electron microscope, for example, when an attempt is made to observe the state of the bottom of a narrow hole formed in a semiconductor sample (for example, a silicon wafer), secondary electrons generated at the bottom are generated on a wall around the narrow hole. It is re-absorbed and difficult to detect. In such a case, if a negative potential is applied to the sample, secondary electrons can be easily emitted from the hole. FIG. 2 schematically shows a scanning electron microscope in which a high voltage is applied to a sample for such a special purpose. In the figure, the same reference numerals as those used in FIG. 1 indicate the same components.

In FIG. 1, reference numeral 10 denotes a conductive sample mounting table on which the sample 6 is mounted, and 11 denotes an insulator for electrically insulating the sample mounting 10 from the sample stage 8. Reference numeral 12 denotes a high voltage introduction terminal which is mounted so as to penetrate the wall surface of the sample chamber 7 and guides a high voltage from outside the sample chamber into the sample chamber. The space is brazed. Reference numeral 13 denotes the sample mounting 10 and the high voltage introduction terminal 12
And a high-voltage cable for applying a high potential to the sample 6 by connecting to Further, although not particularly shown, outside the sample chamber,
Another high voltage cable is provided for supplying a high voltage from a high voltage power supply (not shown) to the high voltage introduction terminal 12.

[0006]

Now, FIG.
A scanning electron microscope in which a high voltage is applied to a sample can be used for observation and inspection of the bottom of a contact hole formed in a semiconductor sample.

However, for such a purpose, the voltage to be applied to the sample requires a high voltage of about -10 kV to -20 kV or more, and as the diameter of the semiconductor sample (eg, wafer) increases, the The range of movement of the stage in the X direction, Y direction, and the like also increases. Moreover, it is frequently driven at a considerably high speed.

Here, the high-voltage cable 13 has a core wire embedded at the center of a cylindrical insulating member (for example, Teflon (registered trademark)) layer, and a braided wire is provided around the cylindrical insulating member layer. It has a structure in which the circumference of the knitted wire is covered with a durable cloth or the like. The larger the voltage to be transmitted, the larger the diameter of the insulating layer in consideration of the prevention of edge discharge, and accordingly the flexi The ability is low.

For this reason, if a stress is applied to such a high-voltage cable every time the stage is moved, the cable will be damaged in a short time.

Also, due to the low flexibility of the high-voltage cable, the stage itself does not move smoothly, and as a result, the sample moving accuracy deteriorates.

The present invention has been made to solve such a problem, and an object of the present invention is to provide a novel high voltage introducing mechanism.

[0012]

According to the present invention, there is provided a high-voltage introducing mechanism for applying a high voltage to a target in a chamber. A movable rail slidable on a fixed rail fixed on a base is attached to the stage, and the movable rail and the target mounting table are connected by a cable, and a voltage from a voltage source provided outside the chamber is connected to a cable. The voltage is applied to the fixed rail via

A high-voltage introduction mechanism according to the present invention for achieving this object is a high-voltage introduction mechanism for applying a high voltage to a target in a chamber, the first mechanism being movable in a first direction on a base. Stage, the first stage on the first stage
A second stage movable in a second direction perpendicular to the first direction, and a target mounting table mounted on the second stage, the second stage being fixed to the first stage on the base. Attaching a first movable rail slidable to a first fixed rail, attaching a second movable rail slidable to a second fixed rail fixed on the first stage to the second stage, Cables are respectively connected between the first movable rail and the second fixed rail and between the second movable rail and the target mounting table, and a voltage from a voltage source provided outside the chamber is applied to the first movable rail via a cable.
It is characterized in that the voltage is applied to the fixed rail.

[0014]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 3 shows an example of a sample stage mechanism provided in a sample chamber of a scanning electron microscope provided with the high voltage introducing mechanism of the present invention.

In the figure, 21 is a stage base, 22 is an X-direction stage, and 23 is a Y-direction stage.
It is formed of an electrically insulating material such as ceramics.
Reference numeral 24 denotes an X-axis rail made of a conductive material, which is composed of two rails. One rail 24A is fixed on the stage base 21, and a convex portion is formed on the rail along the longitudinal direction. ing. The other rail 24B is fixed to the X-direction table 22, and a concave groove is formed in the rail in the longitudinal direction. The two rails are configured such that the protruding portion of one rail 24A is fitted into the concave groove of the other rail 24B so that when the X-direction table 22 moves, one rail 24A can slide with respect to the other rail 24B. I have. Reference numeral 25 denotes a Y-axis rail made of a conductive material, which is composed of two rails. One rail 25A is fixed on the X-direction stage 22, and the rail has a convex portion along the longitudinal direction. Is formed. The other rail 25B is fixed to the Y-direction table 23,
A concave groove is formed in the rail along the longitudinal direction.
In the two rails, the protrusion of one rail 25A is fitted into the groove of the other rail 25B, and the Y-direction table 23
During the movement, one rail 25A is slidable with respect to the other rail 25B.

Reference numeral 26 denotes a sample mounting table made of a conductive material, which is fixed on the Y-direction stage 23.

Reference numeral 27 denotes a high-voltage introduction cable having one end connected to the high-voltage introduction terminal (not shown) described in the scanning electron microscope shown in FIGS. 1 and 2, and the other end connected to one of the X-axis rails 24A. ing.

Reference numeral 28 denotes one end of the X-axis rail 24B.
, A high-voltage cable having the other end connected to one of the Y-axis rails 25A, a high-voltage cable 29 having one end connected to the other 25B of the Y-axis rail, and the other end connected to the sample mounting table 26. It is.

In the apparatus having such a configuration, a high voltage inside the sample chamber is supplied from a power supply (not shown) provided outside the sample chamber via a high voltage cable (not shown) and a high voltage introduction terminal (not shown). The high voltage sent to the introduction cable 27
The voltage is applied to a sample (not shown) via the X-axis rail 24, the high voltage cables 28 and 29, and the sample mounting table 26.

Now, in order to observe a desired area of the sample (not shown) placed on the sample mounting table 26, the X-direction stage 22 and the Y-direction stage 22 are moved by a stage driving mechanism (not shown).
The sample is moved by moving the direction stage 23.

For example, when the X-direction stage 22 is moved by a stage drive mechanism (not shown), the X-axis rail 24B fixed to the X-direction stage 22 is moved with respect to the X-axis rail 24A fixed to the stage base 21. The X-direction stage 22 moves in the X-direction by sliding. At this time, since the Y-axis rail 25, the sample mounting table 26, and the sample (not shown) mounted on the X-direction stage 22 all move in the X-direction in synchronization with the movement of the X-direction stage 22, a high voltage is applied. Cable 27, high-voltage cable 28,
29 is not moved by this movement.

When the Y-direction stage 23 is moved by a stage driving mechanism (not shown), the Y-axis rail 25B fixed to the Y-direction stage 23 is
By sliding with respect to the Y-axis rail 24A fixed to 2, the Y-direction stage 23 moves in the X-direction. At this time, the sample mounting table 26 placed on the Y-direction stage 23
And all the samples (not shown) move in the Y direction in synchronization with the movement of the Y direction stage 23, and the Y direction table 23 and the Y
Since the X-direction stage 22, the X-axis rail 24 and the stage base 21 below the axis rail 25B do not move by this movement, the high-voltage introduction cable 27 and the high-voltage cables 28 and 29 do not move by this movement. .

Even if the sample is moved through the sample stage in this way, the high-voltage cable and the high-voltage introduction cable provided in the sample chamber do not move at all with this movement.
Therefore, deterioration and breakage of the high-voltage cable and the high-voltage introduction cable due to the movement of the sample are eliminated, and the accuracy of the sample movement does not decrease.

In the above example, the other rail is slidable with respect to one rail. However, in order to prevent the high voltage applied to the sample from fluctuating due to poor contact between the rails, A contact such as a brush may be provided on the contact surface of the rail.

In the above example, the stage base and the X and Y direction stages are made of an electrically insulating material. However, it is sufficient that the rail and these stage bases and stages are electrically insulated. Each stage may be formed of a conductive material if it is attached to the stage base or each stage via a mechanical insulating member.

In the above-described example, the case where a high voltage is applied to the sample in the sample chamber of the scanning electron microscope has been described as an example. However, it is needless to say that the present invention is not limited to such a case. For example,
In the case where a target such as a wafer is held on a target mounting table by an electrostatic chuck in a target chamber,
For example, a high voltage is applied to an electrode provided in a mounting table made of an insulating material. The high voltage introducing mechanism can be applied to such a high voltage introducing system. In a charged particle beam apparatus, a target such as a sample or a material is scanned with a charged particle beam to perform a predetermined process, and the target is scanned based on secondary electrons and secondary ions obtained from the target by this scanning. We conduct surface observation and analysis. In such a charged particle beam apparatus, by applying a deceleration voltage to the target, the beam is incident on the focusing lens with high energy, and the beam is narrowly focused by irradiating the target with the decelerated beam. At the same time, damage to the target is prevented, but the high voltage introducing mechanism can be applied to such a system for applying a deceleration voltage to the target.

[Brief description of the drawings]

FIG. 1 shows a schematic example of a scanning electron microscope.

FIG. 2 shows a schematic example of a scanning electron microscope in which a high voltage is applied to a sample.

FIG. 3 shows an example of a sample stage mechanism provided in a sample chamber of a scanning electron microscope provided with the high voltage introducing mechanism of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Electron microscope column 2 ... Electron gun 3 ... Focusing lens 4 ... Objective lens 5 ... Scanning coil 6 ... Sample 7 ... Sample chamber 8 ... Sample stage 9 ... Detector 10 ... Sample mounting table 11 ... Insulator 12 ... High voltage Introduction terminal 13 ... High voltage cable 21 ... Stage base 22 ... X direction stage 23 ... Y direction stage 24, 24A, 24B ... X axis rail 25, 25A, 25B ... Y axis rail 26 ... Sample mounting table 27 ... High voltage introduction cable 28,29… High voltage cable

Claims (2)

[Claims] 1. A high voltage introducing mechanism for applying a high voltage to a target in a chamber, the movable mechanism being slidable on a stage on which a target mounting table is mounted, with respect to a fixed rail fixed on a base. A high voltage introducing mechanism, wherein a rail is attached, the movable rail is connected to the target mounting table by a cable, and a voltage from a voltage source provided outside the chamber is applied to the fixed rail via the cable. 2. A high-voltage introducing mechanism for applying a high voltage to a target in a chamber, the first stage being movable in a first direction on a base, and being perpendicular to the first direction on the first stage. A second stage movable in a second direction,
And a target mounting table mounted on the second stage, and a first movable rail slidable with respect to a first fixed rail fixed on the base is attached to the first stage. Attaching a second movable rail slidable to a second fixed rail fixed on the first stage to the second stage, between the first movable rail and the second fixed rail, and A high voltage introducing mechanism configured to connect a movable rail and the target mounting table with a cable, respectively, and to apply a voltage from a voltage source provided outside the chamber to the first fixed rail via the cable.