JP2001273862A - Charged particle beam apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent damages to a lid opening and closing mechanism. SOLUTION: A limiter switch 31 is attached to a side face of a sample room 2 except for the lid 14. The limiter switch 31 comprises a switch body 33 having a switch 32 mounted on the surface of the switch body 33, and a spring plate 36 having a contact ball 35 fixed at its tip installed on a shaft 34 fixed to the switch body 33. An L shaped section of a metal body 37 is mounted on a side of the lid 14 directly above the limiter switch 31. The limiter switch 31 outputs a switch-on signal when the contact ball 35 fixed at the tip of the spring plate 36 is separated from the metal body 37 and while the contact ball 35 fixed at the tip of the spring plate 36 is touching the metal body 37 the limiter switch 31 does not output any signal. On the inner face of the lid 14 an O ring 38 groove having a depth smaller than the diameter of the cross- section of the O ring 38 is provided and the O ring 38 installed into the groove for vacuum sealing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a charged particle beam apparatus provided with a mechanism for opening a lid of a vacuum chamber.

[0002]

2. Description of the Related Art For example, a sample is observed with a scanning electron microscope, or an I-beam is written on a semiconductor material by an electron beam drawing apparatus.
Observation or processing of an object to be irradiated such as a sample or a material is often performed using a charged particle beam apparatus, such as drawing a C pattern or etching a predetermined location on a material with a focused ion beam apparatus. Are known.

Such an apparatus has a space to be evacuated to a high vacuum (hereinafter referred to as a vacuum chamber). For example, in a scanning electron microscope, a sample chamber where a sample to be observed is placed,
In an electron beam lithography apparatus, a drawing chamber in which a material on which a pattern is drawn is placed, and in a focused ion beam apparatus, a processing chamber in which a material to be processed is placed corresponds to a vacuum chamber.

When such vacuum chamber maintenance, for example, replacement, repair, or cleaning of vacuum chamber parts, is performed, the vacuum chamber is brought to atmospheric pressure, and then the lid of the vacuum chamber is opened to maintain the vacuum chamber. To do.

For example, a case where a lid of a sample chamber of a scanning electron microscope is opened will be described as an example.

FIG. 1 schematically shows a scanning electron microscope. In the drawing, reference numeral 1 denotes a lens barrel, in which an electron gun, a focusing lens for focusing an electron beam from the electron gun, a deflector for scanning the sample with an electron beam, and An objective lens and the like for focusing on the top are accommodated.

Reference numeral 2 denotes a sample chamber. A sample 3 is placed in the chamber, and X, X, and the like are driven by an external drive mechanism (not shown).
A stage 4 and the like configured to be movable in the Y, Z directions and the like are provided. Reference numeral 5 denotes an exhaust port connected to the exhaust pump 7 via the exhaust pipe 6, and reference numeral 8 denotes an exhaust valve provided in the exhaust pipe 6. Reference numeral 9 denotes a vent port connected to a vent gas cylinder 11 via a vent pipe 10, and reference numeral 12 denotes a vent valve provided in the middle of the vent pipe 10. 1
Reference numeral 3 denotes a gantry supporting the scanning electron microscope main body (barrel and sample chamber).

In FIG. 1, reference numeral 14 denotes an upper cover of the sample chamber 2, and the lens barrel 1 is attached to the upper cover. The lid is configured to be opened and closed by a lid opening / closing mechanism. In the figure, reference numeral 15 denotes one part integrated with the lid, and the other part
Is a link to which the hinge 17 is attached. Reference numeral 18 denotes a rack. One end of the rack is integrated with the hinge 17, and the other end is supported by a bearing 19. Reference numeral 20 denotes a rotating shaft having a pinion (a gear meshing with the rack) 21 attached to a portion facing the rack 18. A handle 22 is attached to one end, and the other end is supported by a bearing 23. . 24
Is a hinge attached between the lid 14 and the sample chamber portion excluding the lid, and the hinge 24, the link 15, the pin 16, the hinge 1
7, rack 18, bearing 19, rotating shaft 20, pinion 2
A cover opening / closing mechanism is constituted by the handle 1, the handle 22, and the bearing 23.

In such a scanning electron microscope, when observing a sample, the vent valve 12 is closed, the exhaust valve 8 is opened, and the inside of the sample chamber 2 is exhausted by the exhaust pump 7. The lens barrel 1 is evacuated by a separately provided exhaust pump (not shown).

On the other hand, when performing maintenance or the like in the sample chamber, the exhaust valve 8 is closed and the vent valve 12 is opened.
The vent gas from the vent gas cylinder 11 is introduced into the sample chamber 2 to bring the sample chamber to atmospheric pressure.

In this state, the handle 22 is rotated in one direction to rotate the rotary shaft 20, and the pinion 21 lowers the rack 18 based on the rotation. Since the hinge 17 descends as the rack descends, the link 15
The lid 14 of the sample chamber integrated with the above is rotated clockwise about the hinge 24 as appropriate. As a result, the lid 14 of the sample chamber is opened at an appropriate angle. When closing the lid 14, the handle 22 is rotated in the opposite direction.

Here, the lens barrel 1 having a considerable weight is attached to the lid 14 of the sample chamber, and opening and closing the lid manually requires a considerable burden on the operator.
In addition, the weight of the lid itself and the lens barrel has increased significantly due to the recent increase in size of the entire apparatus, and it has become difficult to manually open and close the lid.

Accordingly, as shown in FIG. 2, a motor 25 is used in place of the handle 22 to make the lid opening / closing mechanism electric. In the figure, 26 is a motor support, 27 is a motor drive circuit, 28 is a pressure sensor for sensing the pressure in the sample chamber 2, and 29 is a control device. The pressure sensor 28 is configured to set a pressure value corresponding to the atmospheric pressure, and to send a signal to the control device 29 when the pressure in the sample chamber reaches the set atmospheric pressure.

Such an electrically operated lid opening / closing mechanism operates as follows.

When performing maintenance or the like in the sample chamber, the exhaust valve 8 is closed, the vent valve 12 is opened, and the vent gas from the vent gas cylinder 11 is introduced into the sample chamber 2 to bring the sample chamber to atmospheric pressure. In this state, since the pressure sensor 28 sends a signal to the control device 29, the control device 29 sends a lid open command to the motor drive circuit 27, that is, a one-way rotation command to open the lid 14 by a predetermined angle. In response to the command, the motor 25 rotates the rotating shaft 20 in one direction by a predetermined amount. The rack 18 is lowered by the binion 21 based on the rotation, and the hinge 17 is lowered as the rack is lowered. Therefore, the lid 14 of the sample chamber integrated with the link 15 is rotated clockwise about the hinge 24 as appropriate. I do. As a result, the lid 14 of the sample chamber is opened at an appropriate angle. When closing the lid 14, a lid closing command is sent from the control device 29, and based on the command, the rotating shaft 2 is closed.
0 is rotated in the direction opposite to the above direction, and the rack 18 is raised by a predetermined amount.

[0016]

The use of a motorized lid opening / closing mechanism has made it possible to smoothly open / close a heavy-weight lid. Problem has occurred.

Usually, when transporting the apparatus, the lid 1 is used.
4, for example, as shown in FIG.
0B, 30C, and 30D (30B, 30C, and 30D are not shown), but before and after the transportation, the operator erroneously issues a lid opening command to the control device 29 in a state where the screw is tightened. You may enter it. In that case, the pressure sensor 28 senses that the inside of the sample chamber is at atmospheric pressure, a signal is sent from the pressure sensor to the control device 29, and the control device sends a lid open command to the motor drive circuit 27. . Therefore, an overload is applied to a part of the lid opening / closing mechanism, and in the worst case, it may be damaged.

A pressure value corresponding to the atmospheric pressure is set in the pressure sensor 28 in advance, and the pressure of the room in which the device is installed fluctuates from the set atmospheric pressure as time passes from the setting. May be. When this fluctuation is higher than the atmospheric pressure at the time of setting, the pressure sensor 2 is operated in spite of the fact that the pressure in the sample chamber is negative with respect to the pressure in the room in which the apparatus is installed.
8 sends a signal to the control device 29. Therefore, lid 1
4. Since the lid opening / closing mechanism tries to open the lid while pressure is applied to the entire surface, the lid opening / closing mechanism is overloaded, and in the worst case, the opening / closing mechanism may be damaged.

The present invention has been made to solve such problems, and an object of the present invention is to provide a novel charged particle beam device.

[0020]

According to the present invention, there is provided a charged particle beam apparatus comprising: a lift body for raising and lowering a link to which a lid of a vacuum chamber is fixed; a motor for raising and lowering the lift body; A lid opening / closing mechanism comprising an O-ring inserted therebetween, a unit for issuing a signal based on the movement of the lid based on the elastic force of the O-ring, and a control device for operating the motor based on a signal from the unit. It is characterized by having. The charged particle beam apparatus according to the present invention further includes a lift body for rotating a link fixing the lid of the vacuum chamber around a hinge attached across the lid and the vacuum chamber, and a motor for moving the lift body up and down. An O-ring inserted between the lid and the vacuum chamber, means for issuing a signal based on the movement of the lid based on the elastic force of the O-ring, and control for operating the motor based on a signal from the means A lid opening / closing mechanism comprising a device is provided.

[0021]

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

FIG. 3 shows a partial schematic example of a main part (sample chamber) of a scanning electron microscope shown as an example of the charged particle beam apparatus of the present invention. In the figure, the components having the same symbols as those used in FIG. 2 indicate the same components.

In the figure, reference numeral 31 denotes a limiter switch attached to the side of the sample chamber excluding the lid 14, and a switch 32 is provided on the surface.
And a spring plate 36 attached to a shaft 34 fixed to the main body 33 and having a contact ball 35 at the tip. A metal body 3 having an L-shaped cross section is provided on a side surface of the lid 14 immediately above the limiter switch.
7 is attached. The limiter switch 31
A switch-on signal is issued when the contact ball 35 of the spring plate 36 is separated from the metal body 37, and the contact ball 3 of the spring plate 36
It is configured such that no signal is emitted when 5 is in contact with metal body 37. An O-ring groove having a depth smaller than the diameter of the O-ring to be fitted therein is provided on the inner surface side of the lid 14 (the surface opposite to the sample chamber 2 excluding the lid 14). As shown in FIG. 3B, an O-ring 38 for vacuum sealing is fitted.

In the case of the apparatus shown in FIG. 2, the control device 29 issues a lid open command to the motor drive circuit 27 when a signal is sent from the pressure sensor 28. In the example shown in (1), the controller 29 issues a lid open command to the motor drive circuit 27 only when a signal from the pressure sensor 58 and a switch-on signal from the limiter switch 31 are both sent. .

However, when the inside of the sample chamber 2 is in a vacuum state,
Due to the pressure difference in the room where the scanning electron microscope is placed, the lid 1
Reference numeral 4 denotes a state in which the O-ring 38 is crushed by being strongly pulled toward the sample chamber 2 except for the lid 14. Accordingly, since the contact ball 35 of the spring plate 36 of the limiter switch 31 is in contact with the metal body 37 and the limiter switch 31 does not emit any signal, the control device 29 issues a lid open command to the motor drive circuit 27. There is no.

Also, even if the inside of the sample chamber 2 is not in a vacuum state, the screws 30A, 30B, 30C, 30D (30B, 30C,
When the lid 14 is fixed to the sample chamber by 30D (not shown), the O-ring 38 is in a crushed state by a screw tightening force. Therefore, the contact ball 35 of the spring plate 36 of the limiter switch 31 is
Is in contact with Therefore, also in this case, the contact ball 35 of the spring plate 36 of the limiter switch 31 is in contact with the metal body 37, and the limiter switch 31 does not emit any signal. No open command is issued.

On the other hand, when the lid 14 is not fixed to the sample chamber with a screw and the pressure in the sample chamber becomes equal to a preset atmospheric pressure and there is almost no difference from the pressure in the chamber at that time, The lid 14 floats up to the opposite side of the sample chamber due to the elastic force (repulsive force) of the O-ring 38, and as shown in FIG.
The contact ball 35 of the spring plate 36 of the limiter switch 31 is separated from the metal body 37. When the contact ball 35 separates from the metal body 37, a switch-on signal is issued from the limiter switch 31 to the control device 29. At this time, since the pressure in the sample chamber is equal to the preset atmospheric pressure, a signal is also sent from the pressure sensor 28 to the control device 29.

Upon receiving signals from the pressure sensor 28 and the limiter switch 31, the control device 29 sends a lid open command to the motor drive circuit 27. As a result, as described in the description of the apparatus in FIG. 2, the lid 14 of the sample chamber is opened at an appropriate angle. When the lid 14 is closed, a lid closing command is sent from the control device 29, and based on the command, the rotating shaft 20 rotates in the direction opposite to the above direction, and the rack 18 is raised by a predetermined amount. .

The O-ring used in the above example may be made of rubber or metal.

In the above example, when signals from the pressure sensor 28 and the limiter switch 31 are received, the control device 28
Is configured to send a lid open command to the motor drive circuit 27, but the control device 28 is configured to send a lid open command to the motor drive circuit 27 only by a signal from the limiter switch 31. No problem.

As described above, the lid is not fixed with the screw,
Also, only when the pressure in the sample chamber becomes the set atmospheric pressure, the pressure becomes almost equal to the pressure in the room where the apparatus is installed, and the O-ring used for vacuum sealing floats to some extent due to the repulsive force, Since the opening operation of the lid opening / closing mechanism is started, even if the operator inputs a lid opening command to the control device 29 in a state where the screw is tightened by mistake, the lid opening operation of the lid opening / closing mechanism is not started. Further, the pressure in the sample chamber becomes the set atmospheric pressure, and the pressure sensor 28
Even if a signal is issued, if the pressure in the room where the device is installed becomes higher than the set pressure, the opening operation of the lid opening / closing mechanism is not started, so that the lid opening / closing mechanism is not overloaded and the lid opening / closing mechanism is not overloaded. The opening / closing mechanism is prevented from being damaged.

The shape of the metal body 37 is not limited to an L-shape. The point is that the metal body 37 can be brought into or out of contact with the switch 32 by the movement of the lid 14 based on the elastic force of the O-ring 38. . Also, the metal member or the limiter switch 31
May be mounted on a side surface which is different from the mounting side surface by 90 degrees.

In the above-described example, the switch using the limiter switch has been described. However, another switch mechanism such as a photoelectric switch may be used instead of such a switch. For example, the light emitting unit 41 and the light receiving unit 42 are provided on the side of the sample chamber except the lid 14.
Is attached, and a metal body 44 having an L-shaped cross section with a shielding plate 43 attached to the tip is attached to the side surface of the lid 14 immediately above the switch. And lid 1
When the sample 4 is fixed with a screw or when the inside of the sample chamber 2 is in a vacuum state, the O-ring 38 is crushed by the atmospheric pressure, and as shown in FIG.
From the light to the light receiving section 42, while the cover 14
Is not fixed with a screw and the inside of the sample chamber 2 is in the atmospheric pressure state, and there is almost no difference from the pressure in the apparatus installation room, as shown in FIG. Thus, the shielding plate 43 does not block the light from the light emitting section 41 to the light receiving section 42. In the latter case, the control device 29 issues a lid open command to the motor drive circuit 27.

In the above example, the present invention has been described by taking the opening and closing of the sample chamber of the scanning electron microscope as an example. However, the present invention is not limited to such an example. It can be used for opening and closing other vacuum chambers such as opening and closing the processing chamber of the apparatus.

[Brief description of the drawings]

FIG. 1 shows a schematic example of a scanning electron microscope provided with a manual lid opening / closing mechanism.

FIG. 2 shows a schematic example of a scanning electron microscope provided with a motorized lid opening / closing mechanism.

FIG. 3 schematically shows a main part of a scanning electron microscope shown as an example of the charged particle beam device of the present invention.

FIG. 4 schematically shows a main part of a scanning electron microscope shown as an example of the charged particle beam device of the present invention.

FIG. 5 schematically shows a main part of a scanning electron microscope shown as another example of the charged particle beam device of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Barrel 2 ... Sample chamber 3 ... Sample 4 ... Stage 5 ... Exhaust port 6 ... Exhaust pipe 7 ... Exhaust pump 8 ... Exhaust valve 9 ... Vent port 10 ... Vent pipe 11 ... Vent gas cylinder 12 ... Vent valve 13 ... Stand 14 ... lid 15 ... link 16 ... pin 17 ... hinge 18 ... rack 19 ... bearing 20 ... rotating shaft 21 ... pinion 22 ... handle 23 ... bearing 24 ... hinge 25 ... motor 26 ... motor support 27 ... motor drive circuit 28 ... pressure sensor 29 ... Control device 30A, 30B, 30C, 30D ... Screw 31 ... Limit switch 32 ... Switch 33 ... Switch body 34 ... Shaft 35 ... Contact ball 36 ... Spring plate 37 ... Metal body 38 ... O-ring 40 ... Photoelectric switch body 41 ... Light emitting unit 42 ... Light receiving unit 43 ... Shielding plate 44 ... Metal body

Claims (8)

[Claims] A lift body for raising and lowering a link to which a lid of a vacuum chamber is fixed; a motor for raising and lowering the lift body; an O-ring inserted between the lid and the vacuum chamber;
A charged particle beam apparatus comprising: a means for generating a signal based on the movement of the lid based on an elastic force of a ring; and a control device for operating the motor based on a signal from the means. 2. A lift body for rotating a link fixing a lid of the vacuum chamber around a hinge mounted on the lid and the vacuum chamber, a motor for moving the lift body up and down, the lid and the vacuum chamber. A lid opening / closing mechanism, comprising: an O-ring inserted between the O-rings; a unit for generating a signal based on the movement of the lid based on the elastic force of the O-ring; Charged particle beam device equipped with 3. The vacuum chamber is a room provided with an object to be irradiated with a charged particle beam.
A charged particle beam apparatus as described in the above. 4. The charged particle beam device according to claim 1, wherein the set pressure is an atmospheric pressure. 5. The charged particle beam device according to claim 1, wherein a hinge is attached to the link via a pin, and the hinge is fixed to a lift rod. 6. The charged particle beam apparatus according to claim 5, wherein the lift rod forms a rack, and a binion that contacts the rack is attached to a rotation shaft of the motor. 7. A limit switch is mounted on a side surface of the vacuum chamber, a metal body is mounted on a side surface of a lid connected to the side surface, and based on a moving distance based on an elastic force of an O-ring of the lid. 3. The charged particle beam apparatus according to claim 1, wherein the limit switch emits a signal or does not emit a signal. 8. A photoelectric switch is mounted on a side surface of the vacuum chamber, and a metal body is mounted on a side surface of a lid connected to the side surface, and the photoelectric switch issues a signal based on a moving distance of the lid. 3. The charged particle beam device according to claim 1, wherein the charged particle beam device emits or does not emit.
Charged particle beam device.