JP3814095B2 - High voltage introduction mechanism - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a high voltage introduction mechanism configured to apply a high voltage to a target.
[0002]
[Prior art]
In many cases, a high voltage is applied to the target. For example, a scanning electron microscope will be described as an example.
[0003]
FIG. 1 shows an outline of a scanning electron microscope, in which 1 is a scanning electron microscope barrel maintained at a high vacuum, 2 is an electron gun for generating an electron beam, and 3 and 4 are electron beams. A focusing lens and an objective lens for focusing and narrowing. Reference numeral 5 denotes a scanning coil for two-dimensionally scanning the target (sample in the case of a scanning electron microscope) 6 with an electron beam. Reference numeral 7 denotes a sample chamber maintained at 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 direction and the Y direction by a stage drive 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 the outside of the sample chamber into the sample chamber via an air lock chamber (not shown) and placed on the sample stage 8. Reference numeral 9 denotes a detector for detecting secondary electrons generated from the sample by irradiation with an electron beam.
[0004]
Although not particularly shown, the scanning electron microscope further receives signals from the detector 9 and an electric circuit for controlling the electron gun 2, the lenses 3 and 4, the scanning coil 5, the sample stage 8, and the like. An electric circuit for amplification, a CRT for displaying an electron microscope image using the signal, and the like are provided.
In such a scanning electron microscope, the electron beam generated by the electron gun 2 is finely focused by the focusing lens 3 and the objective lens 4 and irradiated onto the sample 6, and the sample 6 is scanned two-dimensionally by the scanning coil 5. To do. Secondary electrons generated by the scanning are detected by the detector 9 and displayed as a scanning microscope image on a CRT (not shown).
By the way, in such a scanning electron microscope, for example, when the state of the bottom of a narrow hole formed in a semiconductor sample (for example, a silicon wafer) is to be observed, the secondary electrons generated at the bottom are applied to the wall around the narrow hole. It will be reabsorbed and difficult to detect. In such a case, if a negative potential is applied to the sample, the emission of secondary electrons from the hole can be facilitated.
FIG. 2 schematically shows a scanning electron microscope configured to apply a high voltage to the sample for such a special purpose. In the figure, the same reference numerals as those used in FIG. 1 denote the same components.
[0005]
In the figure, 10 is a conductive sample mounting table on which the sample 6 is mounted, and 11 is an insulator for electrically insulating the sample mounting 10 and the sample stage 8. Reference numeral 12 denotes a high voltage introduction terminal which is attached so as to penetrate the wall surface of the sample chamber 7 and guides a high voltage from the outside of the sample chamber into the sample chamber. In order to maintain a vacuum in the sample chamber, There is a row between them. Reference numeral 13 denotes a high voltage cable for connecting the sample mounting 10 and the high voltage introduction terminal 12 to give a high potential to the sample 6. Further, although not particularly illustrated, another high voltage cable for supplying a high voltage from a high voltage power source (not shown) to the high voltage introduction terminal 12 is provided outside the sample chamber.
[0006]
[Problems to be solved by the invention]
Now, the scanning electron microscope of the type that applies a high voltage to the sample shown in FIG. 2 can be used for observation / inspection of the bottom of the contact hole formed in the semiconductor sample.
[0007]
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 naturally, as the diameter of the semiconductor sample (for example, a wafer) increases, The range of movement in the direction, the Y direction, etc. also increases. Moreover, it is driven frequently at a fairly high speed.
[0008]
The high-voltage cable 13 has a core wire embedded in the center of a cylindrical insulating member (for example, Teflon) layer, surrounds the cylindrical insulating member layer with a knitted wire, and surrounds the knitted wire. Is covered with a strong cloth, etc. The larger the voltage to be transmitted, the larger the diameter of the insulating layer in consideration of edge discharge prevention, and the lower the flexibility accordingly. .
[0009]
For this reason, when such a high voltage cable is subjected to stress each time the stage is moved, the cable is damaged in a short time.
[0010]
In addition, due to the low flexibility of the high voltage cable, the stage movement itself does not proceed smoothly, and as a result, the specimen movement accuracy deteriorates.
[0011]
The present invention has been made to solve such problems, and an object thereof is to provide a novel high voltage introduction mechanism.
[0012]
[Means for Solving the Problems]
The high voltage introduction mechanism of the present invention for achieving this object is a high voltage introduction mechanism for applying a high voltage to the target in the chamber, and is fixed on the base to the stage on which the target placement table is placed. A movable rail slidable with respect to the fixed rail is attached, the movable rail and the target mounting base are connected with a cable, and a voltage from a voltage source provided outside the chamber is applied to the fixed rail via the cable. It is characterized by that.
[0013]
In order to achieve this object, a high voltage introduction mechanism of the present invention is a high voltage introduction mechanism for applying a high voltage to a target in a chamber, wherein the first stage is movable in a first direction on a base, A second stage that is movable in a second direction perpendicular to the first direction on the first stage; and a target mounting table placed on the second stage. The first movable rail slidable with respect to the first fixed rail fixed on the base is attached, and the second stage is slidable with respect to the second fixed rail fixed on the first stage. A second movable rail is attached, and a voltage from a voltage source provided outside the chamber is connected between the first movable rail and the second fixed rail and between the second movable rail and the target mounting table with cables. The Via Bull characterized in that form to apply to the first stationary rail.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0015]
FIG. 3 shows an example of a sample stage mechanism provided in a sample chamber of a scanning electron microscope equipped with the high voltage introduction mechanism of the present invention.
[0016]
In the figure, 21 is a stage base, 22 is an X direction stage, and 23 is a Y direction stage, both of which are formed of an electrically insulating material such as ceramics. Reference numeral 24 denotes an X-axis rail made of a conductive material. The X-axis rail is composed of two rails. One rail 24A is fixed on the stage base 21, and a convex portion is formed along the longitudinal direction of the rail. ing. The other rail 24B is fixed to the X-direction table 22, and a concave groove is formed in the rail along the longitudinal direction. The two rails are configured such that the convex portion of one rail 24A is fitted in the concave groove of the other rail 24B so that one rail 24A can slide relative to the other rail 24B when the X-direction table 22 moves. It is. 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, and a concave groove is formed in the rail along the longitudinal direction. In the two rails, the convex portion of one rail 25A is fitted in the concave groove of the other rail 25B, and when the Y-direction table 23 is moved, one rail 25A can slide relative to the other rail 25B. It is.
[0017]
Reference numeral 26 denotes a sample mounting table made of a conductive material, which is fixed on the Y-direction stage 23.
[0018]
Reference numeral 27 denotes a high voltage introduction cable having one end connected to a high voltage introduction terminal (not shown) described in the scanning electron microscope shown in FIGS. 1 and 2, and the other end is connected to one end 24A of the X-axis rail.
[0019]
28 is a high voltage cable having one end connected to the other 24B of the X-axis rail and the other end connected to one 25A of the Y-axis rail. 29 has one end connected to the other 25B of the Y-axis rail and the other end is This is a high voltage cable connected to the sample mounting table 26.
[0020]
In the apparatus having such a configuration, a high voltage introduction cable 27 in the sample chamber is supplied from a power source (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 is applied to the sample (not shown) via the X-axis rail 24, the high-voltage cables 28 and 29, and the sample mounting table 26.
[0021]
Now, in order to observe a desired region of a sample (not shown) placed on the sample mounting table 26, the X direction stage 22 and the Y direction stage 23 are moved by a stage drive mechanism (not shown). Move the sample.
[0022]
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 slides with respect to the X-axis rail 24A fixed on the stage base 21. As a result, the X direction stage 22 moves in the X direction. At this time, the Y-axis rail 25, the sample mounting table 26, and the sample (not shown) placed on the X-direction stage 22 all move in the X direction in synchronization with the movement of the X-direction stage 22, so that a high voltage is introduced. The cable 27 and the high voltage cables 28 and 29 are not moved by this movement.
[0023]
When the Y direction stage 23 is moved by a stage drive mechanism (not shown), the Y axis rail 25B fixed to the Y direction stage 23 slides with respect to the Y axis rail 24A fixed to the X direction stage 22. As a result, the Y-direction stage 23 moves in the X direction. At this time, the sample mounting table 26 and the sample (not shown) placed on the Y direction stage 23 all 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 axis rail 25B. Since the X-direction stage 22, the X-axis rail 24 and the stage base 21 below are not moved by this movement, the high-voltage introduction cable 27 and the high-voltage cables 28 and 29 are not moved by this movement.
[0024]
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 respect to this movement. Accordingly, the high-voltage cable and the high-voltage introduction cable are not deteriorated or broken by the sample movement, and the accuracy of the sample movement is not lowered.
[0025]
In the above example, the other rail is slidable with respect to one rail. However, any rail can be used so that the high voltage applied to the sample does not fluctuate due to poor contact between the rails. A contact such as a brush may be provided on the contact surface.
[0026]
In the above example, the stage base and the X and Y direction stages are electrically insulating materials. However, since the rail and these stage base and stage only need to be electrically insulated, the rail is electrically insulated. Each stage may be made of a conductive material if it is attached to the stage base or each stage via the.
[0027]
In the above example, the case where a high voltage is applied to the sample in the sample chamber of the scanning electron microscope is taken as an example, but it goes without saying that the present invention is not limited to such a case. For example, when a target such as a wafer is held on the target mounting table by an electrostatic chuck in the target chamber, for example, a high voltage is applied to an electrode provided in the mounting table made of an insulating material. The high voltage introduction mechanism can also be applied to a voltage introduction system. In the charged particle beam apparatus, a target such as a sample or a material is scanned with a charged particle beam, and predetermined processing is performed. Based on secondary electrons or 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 in a high energy state, and the target is irradiated with the decelerated beam, thereby focusing the beam finely. At the same time, damage to the target is prevented, but the high voltage introduction mechanism can be applied to a deceleration voltage application system to such a 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 that applies a high voltage to a sample.
FIG. 3 shows an example of a sample stage mechanism provided in a sample chamber of a scanning electron microscope equipped with a high voltage introduction mechanism of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Electron microscope barrel 2 ... Electron gun 3 ... Condensing lens 4 ... Objective lens 5 ... Scanning coil 6 ... Sample 7 ... Sample chamber 8 ... Sample stage 9 ... Detector 10 ... Sample mounting base 11 ... Insulator 12 ... High voltage Introduction terminal 13 ... High voltage cable 21 ... Stage base 22 ... X direction stage 23 ... Y direction stages 24, 24A, 24B ... X axis rails 25, 25A, 25B ... Y axis rail 26 ... Sample mounting table 27 ... High voltage introduction cable 28, 29 ... high voltage cable

Claims (2)

A high voltage introduction mechanism for applying a high voltage to a target in a chamber, wherein a movable rail slidable with respect to a fixed rail fixed on a base is attached to a stage on which a target mounting table is mounted, A high voltage introduction mechanism configured to connect a movable rail and the target mounting table with a cable and apply a voltage from a voltage source provided outside the chamber to the fixed rail through the cable. A high voltage introduction 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 a second direction perpendicular to the first direction on the first stage A second stage movable to the first stage, and a target stage placed on the second stage, and slides on the first stage with respect to the first fixed rail fixed on the base. A movable first movable rail is attached, a second movable rail slidable with respect to a second fixed rail fixed on the first stage is attached to the second stage, and the first movable rail and the second movable rail are attached to the second stage. A cable is connected between the fixed rail and 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 fixed rail via the cable. High voltage introduction mechanism.

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