JP2711898B2 - Non-contact guide type positioning table - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a non-contact guide type positioning table used in various precision processing devices, precision measurement devices, and biotechnology devices.

[Prior Art] In producing a positioning table of a precision processing apparatus, for example, a circuit pattern of a semiconductor, a fine dense image of a mask having a desired pattern is optically transferred with ultraviolet rays onto a semiconductor substrate coated with a photosensitive agent. Of the guides and drive sources of the substrate and mask movement positioning tables in the exposure apparatus that performs the rough movement, a sliding guide surface and a ball screw motor drive are used. A piezoelectric element, a non-contact air bearing surface, a linear motor, and the like are used.

[Problems to be solved by the invention]

Precision equipment such as semiconductor circuit pattern exposure equipment
It requires a positioning accuracy and a parallelism accuracy of the order of 0.01 μm, and must be operated in a high vacuum to avoid dust in the air and to prevent physical and chemical changes of the substrate and the photosensitive agent.

However, when a sliding guide surface and a ball screw motor drive are used for guiding and driving the positioning table in a vacuum as in the conventional technology, wear due to direct contact of a metal material such as steel or a nonmetal material such as plastic is caused. As a result, dust is generated, and the use of lubricating oil is suppressed, so that solid welding and separation occur.

When using a non-contact air bearing surface, etc.
Large damage and damage to equipment and products due to accidents such as leaks cannot be avoided.

In addition, the positioning table according to the prior art requires various additional means in order to realize positioning accuracy and parallelism accuracy.

[Means for solving the problem]

A non-contact guide type positioning table according to the present invention comprises: a table body; a table supported by a 5-axis control magnetic bearing so as to be horizontally movable; And a connecting member for connecting an external driving device and a moving table inserted through a telescopic hollow member for maintaining a sealed state, and a magnetic bearing current control device. .

[Action]

In the positioning of the table body in the XYZ axis direction and the adjustment of the parallelism, first, each Y-axis position adjusting electromagnet and each Z-axis position adjusting electromagnet of the 5-axis control magnetic bearing are controlled by the control device, When excited, the table body is floated in the hollow portion of the moving table.

The coarse positioning in the X-axis direction is performed by the operation of a non-contact linear motor for horizontal drive, and when the non-contact linear motor for horizontal drive is controlled and operated by the control device, the table body in the floating state is moved along the X-axis at the movable base. To the predetermined position in the direction, and is roughly positioned in the fixed space.

The coarse positioning in the Y-axis direction is performed by operation of an external driving device. When the external drive device is controlled and operated by the control device, the moving table moves to a predetermined position in the Y-axis direction in the vacuum vessel, and eventually, the table body supported by the moving table roughly moves in the Y-axis direction. It will be positioned.

Fine positioning in the X-axis direction is performed by the operation of a well-known driving unit such as a combination of a piezoelectric element and an elastic member. When the driving means is controlled and operated by the control device, the table main body makes a desired minute displacement in the X-axis direction. Accordingly, the table main body is precisely positioned at a desired X-axis direction position in the fixed space with respect to the moving table.

Fine positioning in the Y-axis direction is performed by a Y-axis position adjusting electromagnet of the five-axis control magnetic bearing. When each electromagnet is controlled and operated by the control device, the table body makes a desired minute displacement in the Y-axis direction due to a current difference between opposing electromagnets, that is, a magnetic force difference. Therefore, the table main body is precisely positioned at the desired Y-axis direction position in the fixed space with respect to the moving table.

Fine positioning in the Z-axis direction is performed by a Z-axis position adjusting electromagnet of the 5-axis control magnetic bearing. When each electromagnet is controlled and operated by the control device, the table main body makes a desired minute displacement in the Z-axis direction due to a current difference between the opposing electromagnets, that is, a magnetic force difference. Accordingly, the table main body is precisely positioned at a desired position in the Z-axis direction in the fixed space with respect to the moving table.

Adjustment of the parallelism of the table body can be done with the X axis, Y axis, Z
It is performed by rotational positioning around each axis.

The rotation (rolling) positioning around the X-axis is performed by a Z-axis position adjusting electromagnet. When each electromagnet is controlled and operated by the control device, the table main body makes a desired minute displacement in the Z-axis direction due to a current difference between the opposing electromagnets, that is, a magnetic force difference. In addition, the electromagnet current is controlled so that the directions of displacement of the upper and lower sides of the table body are opposite. Therefore, the table main body is precisely positioned at a desired rotational position about the X-axis with respect to the movable base and, in extension, in the fixed space.

Rotational (yaw) positioning about the Y-axis is performed by a Z-axis position adjusting electromagnet. When each electromagnet is controlled and operated by the control device, the table main body makes a desired minute displacement in the Z-axis direction due to a current difference between the opposing electromagnets, that is, a magnetic force difference. In addition, the electromagnet current is controlled so that the displacement direction is opposite between the left side and the right side of the table body in the X-axis direction. Therefore, the table main body is precisely positioned at a desired rotational position around the Y axis in the fixed space with respect to the moving table.

Rotation (pitching) positioning about the Z-axis is performed by a Y-axis position adjusting electromagnet. When each electromagnet is controlled and operated by the control device, the table main body makes a desired minute displacement in the Z-axis direction due to a current difference between the opposing electromagnets, that is, a magnetic force difference. In addition, the electromagnet current is controlled so that the displacement direction is opposite between the left side and the right side of the table body in the X-axis direction. Therefore, the table main body is precisely positioned at a desired rotation position around the Z axis in the fixed space with respect to the moving table.

〔Example〕

 An embodiment of the present invention will be described with reference to the drawings.

The drawings illustrate a case where a non-contact guide type positioning table is applied to a semiconductor circuit pattern exposure apparatus.

The exposure light beam used in a semiconductor circuit pattern exposure apparatus is usually ultraviolet light (wavelength 200 to 400 °),
X-rays (the number of wavelengths に も) will be used, and strong X
Since the line is a horizontal ray SOR (synchrotron radiation), the non-contact guide type positioning table is required to be an upright type that moves in an upright plane.

In FIG. 1, the horizontal axis is an X axis, the vertical axis is a Y axis, and the vertical axis is a Z axis.

A vacuum vessel 3 is attached to a side surface of the machine casing 1 via a connecting portion 2, and a servomotor 5 is attached to an upper surface of a protrusion 4 from the same side of the machine casing 1 above the vacuum vessel 3. I have.

An upper apron 6 located between the upper surface of the vacuum vessel 3 and the protruding portion 4 and a lower apron 7 located below the lower surface of the vacuum vessel 3 penetrate the connecting portion 2 in the vertical direction and are provided on the connecting portion 2. Slidably supported vertically by sliding bearings 8,8
The books are integrally connected by parallel guide rods 9,9.

A feed screw 10 coupled to a motor shaft end of the servo motor 5 controlled by a control device (not shown) extends downward, and is screwed into a female screw portion 11 provided at a central portion of the upper apron 6,
The lower end is connected to the upper surface of the vacuum vessel 3 while allowing only rotation.

The elevator 12 housed in the vacuum vessel 3 with at least a space in the vertical direction is provided with two parallel upper support rods 13 whose upper surface and the lower surface of the upper apron 6 penetrate the upper wall of the vacuum vessel 3. , 13 and the lower surface thereof and the upper surface of the lower apron 7 are connected by two parallel lower support rods 14, 14 penetrating the lower surface wall of the vacuum vessel 3, so that the upper and lower apron 6, It is integrated with 7. The upper and lower supporting rods 13, 13; 14, 14 are inserted into openings 15, 15, 16, 16, 16 formed in the upper and lower walls of the vacuum vessel 3 with play.

Thus, each of the supporting rods 13, 13; 14, 14 is surrounded and between the lower surface of the upper apron 6 and the upper surface of the vacuum container 3 and between the upper surface of the lower apron 7 and the lower surface of the vacuum container 3, respectively. Bellows 17,17; 18,18 are attached so as to communicate with each other.
Therefore, the openings 15, 15; 16, 16 are closed by the bellows 17, 17; 18, 18 and the lower surface of the upper apron 6; the upper surface of the lower apron 7, so that the vacuum sealed state of the vacuum container 3 is maintained.

The elevator 12 has a hollow portion 19 having a cross section as shown in FIG.
Is a frame formed to penetrate in the X-axis direction, and a quadrangular exposure window 20 is opened in the center of the front wall thereof.

On the inner peripheral surface of the hollow portion 19, the Y-axis position adjusting electromagnets 21 and 22 are provided on the upper and lower surfaces on the left side, and the Y-axis position adjusting electromagnets 23 and 24 are provided on the upper and lower surfaces on the right side so as to face each other.
Electromagnets 25 and 26 for Z-axis position adjustment are located on the front left and
Electromagnets 27 and 28 for adjusting the Z-axis position are located on the upper right front and rear surfaces,
Electromagnets 29, 30 for adjusting the Z-axis position are provided on the front and rear surfaces on the lower side of the center so as to face each other. Further, linear pulse motors 31 and 32 are provided below the rear surfaces of the left and right inner peripheral surfaces of the hollow portion 19, respectively.

Instead of the linear pulse motors 31 and 32, for example, a feedback control type positioning device having both a normal optical scale and a voice coil motor may be used.

Then, each Y-axis position adjusting electromagnet 21, 22, 23, 24 is provided adjacent to each Y-axis position detecting position sensor 33, 34, 35, 36, and each Z-axis position adjusting electromagnet 25, 26,27,28,29,3
Position sensors 37, 38, 39, 4 for each Z-axis position detection adjacent to 0
0, 41, and 42 are provided.

A rectangular plate-shaped table main body 43 is inserted horizontally and vertically into the hollow portion 19, and the upper and lower front and rear surfaces of the table main body 43 have magnetic poles of the electromagnets 21 to 30 and position sensors 33 to 42.
In addition, it contacts the magnetic poles of the linear pulse motors 31, 32. Further, protective bearings 44, 44 are provided at both ends of the lower surface of the hollow portion 19.
, And protective bearings 45, 45,... The protection bearings 44 are rolling bearings, but the protection bearings 45 may be sliding bearings.

Magnetic poles of linear pulse motors 31, 32 and table body 43
Are formed in a comb shape arranged in the X-axis direction. Each pair of opposing electromagnets and each pair of position sensors provided adjacent thereto are connected to a magnetic pole power supply control device as shown in FIG.

FIG. 7 exemplarily shows a pair of opposed electromagnets and position sensors provided adjacent thereto, for example, the electromagnets 25 and 26 and position sensors 37 and 38 provided adjacent thereto. . The position sensor may be provided on only one side, and one of the position sensors 37 and 38 may be omitted.

Each of the position sensors 37 and 38 outputs a detection signal to a control circuit (P
ID operation) is connected so as to be input to a sensor signal processing unit 51 for converting into a voltage level handled in 53, and the sensor signal processing unit 51 is connected to a control circuit 53 via a comparator 52 to which a reference signal is input. It is connected. Control circuit (PID operation) 53
Are connected so that their outputs are input to the coils of the electromagnets 25 and 26 via the amplifiers 54 and 55, respectively.

Further, between the table body 43 and the elevator 12, X
The piezoelectric element urged by the external control device in one direction in the axial direction and the elastic member urged in the other direction are interposed, and the table body 43 is finely displaced to the X axis by the opposing operation thereof. Has become.

The connection of the vacuum pump to the vacuum vessel 3, the connection of the control device to each electromagnet and position sensor, and the piezoelectric element, and the connection of the power supply to the linear pulse motor impair the sealing of the vacuum vessel 3 in a line not shown. It is easy to see what is not done.

The operation and operation of the non-contact guide type positioning table will be described.

In a non-contact guide type positioning table of a semiconductor circuit pattern exposure apparatus, a semiconductor substrate is attached to a table body 43, and a mask image is exposed through an exposure window 20 by X-rays.

At this time, the semiconductor substrate, that is, the table body 43, is accurately positioned (with an accuracy of the order of 0.01 μm) in the XYZ axis direction, and the parallelism is adjusted.

First, the Y-axis position adjusting electromagnets 21, 22, 23, 24 and the Z-axis position adjusting electromagnets 25, 26, 27, 28, 29, 30 are excited by an input from the control device, and the table body 43 is It is placed in a floating state in the hollow part 19 of the twelve.

Rough positioning in the X-axis direction is performed using linear pulse motors 31, 3
It is performed by the operation of 2. When the linear pulse motors 31 and 32 are controlled and operated by a control device (not shown), the table body 43 in a floating state moves X in the hollow portion 19 of the elevator 12.
It moves to a predetermined position in the axial direction and is roughly positioned.

The coarse positioning in the Y-axis direction is performed by the operation of the servomotor 5. When the servomotor 5 is controlled and operated by a control device (not shown), the feed screw 10 is driven to rotate, and the screwed female screw portion 11, that is, the upper apron 6 moves up and down. The elevator 12 moves to a predetermined position in the Y-axis direction in the vacuum vessel 3 while the guide rod 9 is guided by the slide bearings 8,8, and eventually, the table body 43 in the elevator 12
Are roughly positioned in the Y-axis direction.

 Rough positioning in the Z-axis direction is not particularly required.

The coarse positioning in the X-axis direction is performed by joint operation of a piezoelectric element (not shown) and an elastic member. When the piezoelectric element is controlled and operated by the control device, the table body 43 makes a small displacement in the X-axis direction due to the deformation of the piezoelectric element according to the control voltage while being pressed by the elastic element against the piezoelectric element.
Therefore, the table body 43 is precisely positioned at a desired X-axis direction position in the fixed space with respect to the elevator 12.

Electro-magnet for Y-axis position adjustment for precise positioning in the Y-axis direction
21,22; 23,24. When each of the electromagnets 21, 22; 23, 24 is controlled and operated by the control device, the table body 43
Is the current difference between the current to the coils of the electromagnets 21 and 23 and the current to the coils of the electromagnets 22 and 24, that is, Y
Make a small displacement in the axial direction. At that time, the position of the table body 43 with respect to the elevator 12 is detected by the Y-axis position detection position sensors 33, 34; 35, 36, and the detection signal is input to the comparator 52 via the sensor signal processing unit 51, The control circuit 53 compares the electromagnets 21 and 22 for adjusting the Y-axis position so that the detection signal becomes equal to the reference value.
The current to 3,24 is controlled.

Therefore, the table body 43 is precisely positioned at a desired position in the Y-axis direction with respect to the elevator 12 and thus in the fixed space.

Electromagnet for Z-axis position adjustment for precise positioning in the Z-axis direction
25,26; 27,28; 29,30. Each electromagnet 25,26; 27,
28; 29, 30 operated by the control device, the table main body 43 provides a current difference between the current to the coils of the electromagnets 25, 27, 29 and the current to the coils of the electromagnets 26, 28, 30; Causes a minute displacement in the Z-axis direction. that time,
The position of the table body 43 with respect to the elevator 12 is detected by Z-axis position detection position sensors 37, 38; 39, 40; 41, 42, and the detection signal is input to a comparator 52 via a sensor signal processing unit 51. The control circuit 53 controls the current to the Z-axis position adjusting electromagnets 25, 26; 27, 28; 29, 30 so that the detection signal becomes equal to the reference value.

Therefore, the table main body 43 is precisely positioned at a desired position in the Z-axis direction in the fixed space with respect to the elevator 12.

The adjustment of the parallelism of the table body 43 is performed by using the X-axis, Y-axis,
The rotation is performed around each axis of the Z axis.

The rotation (rolling) positioning around the X-axis is performed by the Z-axis position adjusting electromagnets 25, 26; 27, 28; 29, 30.
When each of the electromagnets 25, 26; 27, 28; 29, 30 is controlled and operated by the control device, the current difference between the current to the coils of the electromagnets 25, 27, 30 and the current to the coils of the electromagnets 26, 28, 29, That is, the table body 43 is slightly rotated and displaced around the X-axis by the magnetic force difference. At this time, the position of the table main body 43 with respect to the elevator 12 is determined by the position sensors 37, 38;
The detection signal is detected by the control circuit 53 so that the detection signal is input to the comparator 52 via the sensor signal processing unit 51 and is compared with a reference value of a desired setting, and the detection signal becomes equal to the reference value. Electromagnets for Z-axis position adjustment 25, 26; 27, 28; 29, 3
The current to 0 is controlled.

Therefore, the table main body 43 is precisely positioned at a desired rotation position around the X axis in the fixed space with respect to the elevator 12.

Rotation (yaw) positioning about the Y-axis is also performed by the Z-axis position adjusting electromagnets 25, 26; 27, 28. Each electromagnet 2
5, 26; 27, 28 are controlled and operated by the control device, the table main body 43 is moved by the current difference between the current to the coils of the electromagnets 25, 28 and the current to the coils of the electromagnets 26, 27, that is, the magnetic force difference. It is slightly displaced around the axis. At that time, the position of the table body 43 with respect to the elevator 12 is detected by the Z-axis position detection position sensors 37, 38; 39, 40, and the detection signal is input to the comparator 52 via the sensor signal processing unit 51, The control circuit 53 controls the current to the Z-axis position adjusting electromagnets 25, 26; 27, 28 so that the detection signal is compared with the reference value of the desired setting and the detection signal becomes equal to the reference value.

Therefore, the table main body 43 is precisely positioned at a desired rotation position around the Y axis in the fixed space with respect to the elevator 12.

Rotational (pitching) positioning about the Z-axis is performed by Y-axis position adjusting electromagnets 21, 22; When each of the electromagnets 21, 22; 23, 24 is controlled and operated by the control device, the current difference between the current to the coils of the electromagnets 21, 24 and the current to the coils of the electromagnets 22, 23, that is, the magnetic force difference,
The table main body 43 is slightly displaced by rotation about the Z axis. At that time, the position of the table body 43 with respect to the elevator 12 is detected by the Y-axis position detection position sensors 33, 34; 35, 36,
The detection signal is sent to a comparator 52 via a sensor signal processing unit 51.
The current is supplied to the Y-axis position adjusting electromagnets 21, 22, 23, and 24 by the control circuit 53 so that the detection signal becomes equal to the reference value.

Therefore, the table main body 43 is precisely positioned at a desired rotation position around the Z axis in the fixed space with respect to the elevator 12.

When each electromagnet is not excited at the time of no work or accident, the table body 43 falls from the floating state, but is supported by the protective bearings 44, 44 at least before contacting the Y-axis position adjusting electromagnets 22, 24. You. Therefore, damage to the Y-axis position adjusting electromagnets 22 and 24 is prevented. Also, at this time, even if the table body 43 falls down, it is supported by the protective bearings 45, 45 ... before coming into contact with the Z-axis position adjusting electromagnets 37 to 42, thereby preventing the Z-axis position adjusting electromagnets 37 to 42 from being damaged. Is done.

The above embodiment is an upright type in which the table main body 43 is upright and the elevator 12 as a movable table supporting the table body 43 moves up and down, and the non-contact guide type positioning table is applied to a semiconductor circuit pattern exposure apparatus. This is the case when the horizontal type is configured so that the moving table similar to the elevator 12 moves in the horizontal direction with the table body 43 horizontal.
That is, it can be easily understood that the upright type can be directly rotated by 90 degrees around the X axis to be used in various precision processing devices, precision measurement devices, and biotechnology devices.

In this case, the protection bearings 44 of the hollow portion 19 in the case of the upright type are also provided on the opposing surfaces, and the protection bearings 45, 45... Thus, the protective bearings 44, 44 may be sliding bearings, but the protective bearings 45, 45 ... are rolling bearings.

〔The invention's effect〕

According to the non-contact guide type position table according to the present invention, since it can be displaced in a vacuum and has no mechanical contact portion such as a sliding guide surface and a pole screw motor drive in the displacement,
No dust due to wear due to direct contact. In addition, operation in a vacuum does not require the use of undesired lubricating oil, and there is no danger of solid welding or peeling.

In addition, since the bearings using magnetic bearings are used, fine displacement in each axial direction and fine rotation around each axis can be performed only by controlling the magnetic force, so that there is no need for a bulky additional mechanism. Positioning and parallelism precision adjustment can be easily performed.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional front view of a non-contact guide type positioning table according to an embodiment of the present invention, FIG. 2 is a cross-sectional view taken along the line II-II of FIG. 1, and FIG. FIG. 4 is a front view of an elevator of the non-contact guide type positioning table according to the embodiment of the present invention. FIG. 5 is a non-contact guide type positioning table according to the embodiment of the present invention. FIG. 6 is a cross-sectional view taken along the line VI-VI of FIG. 5, and FIG. 7 is a control circuit of a non-contact guide type positioning electromagnet in the embodiment of the present invention. 1: Machine frame, 2: Connection part, 3: Vacuum container, 4: Projection part 5: Servo motor, 6: Upper apron 7: Lower apron, 8: Sliding bearing, 9: Guide rod 10: Feed screw, 11: Female screw , 12: Elevator 13: Upper support rod, 14: Lower support rod, 15, 16: Open hole 17, 18: Bellows, 19: Hollow, 20: Exposure window 21, 22, 23, 24: Y axis position adjustment Electromagnets 25 to 30: Electromagnets for adjusting the Z axis position 31, 32: Linear pulse motors 33 to 36: Position sensors for detecting the Y axis position 37 to 42: Position sensors for detecting the Z axis position 43: Table body, 44, 45: Protective bearings 46, 47: Magnetic pole part, 51: Signal processing part for sensor 52: Comparator, 53: Control circuit (PID operation) 54, 55: Amplifier

Claims (1)

(57) [Claims] 1. A table body, a table supported by a five-axis control magnetic bearing so as to be freely movable in a horizontal direction, a moving table provided with a non-contact linear motor for driving the table horizontally, and the moving table movable in a direction perpendicular to the table moving direction. Vacuum container housed in
A non-contact guide type positioning table comprising a connecting member for connecting an external driving device and a movable table inserted through a telescopic hollow member for maintaining a sealed state, and a magnetic bearing current controller.