JPS58147134A - Precision plane-shifting device - Google Patents

Abstract

PURPOSE:To perform a highly accurate positioning by a method wherein a rectilinear type microscopic displacement mechanism, which generates microscopic strokes, is brought into a freely coupled or uncoupled state with the member supporting the table which is the member to be displaced, thereby enabling the table to be roughly stepped by a small-sized and simple structure. CONSTITUTION:An X-table 18 is guided to X-axial direction by fixing a linear bearing guide 7 on the base 20 of the precision plane-shifting device which will be used to manufacture electronic parts such as a semiconductor integrated circuit and the like. The second linear bearing guide 7' is fixed on the X-table 18, and a sample table 19 is guided in the Y-axial direction. The linear bearing guide 7' consists of a hydrostatic bearing or a bearing device having small stick slip and friction generated when sliding. A servomotor 5 is attached to a base 20 and a ball screw 6 is installed in such a manner that it can be rotated freely, and a block 22 is constituted in such a manner that it will be moved by turning a screw using a nut 21 which is screw-fitted to the ball screw 6. An arm 23 is fixed to the X-table 18, and the X-table 18 is engaged with the block 22.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a precision plane moving device suitable for moving a table on which a workpiece is placed in a horizontal plane with high precision.

This type of precision plane movement device is used, for example, in the manufacture of electronic components such as semiconductor integrated circuits.

In recent years, with the miniaturization of semiconductor integrated circuits, it has become necessary to form patterns of 1 μm or less.

For this purpose, a highly accurate exposure device is required, and what is essential to this exposure device is a highly accurate movement and positioning device. Therefore, high-precision movement and positioning devices have been proposed in the past, but these devices have separate coarse and fine table feed mechanisms, have complex structures, and are large. was. Furthermore, the coarse feed mechanism cannot perform highly accurate positioning, and even if the fine feed mechanism is capable of highly accurate positioning, it has the disadvantage that the minute feed amount is extremely small. Furthermore, the fine feed mechanism is generally constructed to be placed on the coarse feed mechanism, which increases the height of the entire device, making it inconvenient to handle.

FIG. 1 shows an example of a prior art mobile device that has these drawbacks.

The basic structure consists of two coarse movement tables 1 that move in the X and Y directions of the arrows, and two fine movement tables 2 that are mounted on the coarse movement tables 1 and that also move finely in the X and Y directions. ing. That is, the coarse movement X table 3 is mounted on two linear bearing guides 7 formed on the base. This coarse movement X table 3 is coarsely fed in the direction of arrow X along a linear bearing guide 7 by a servo motor 5 and a ball screw 6 installed on the base. There are two linear bearing guides 7' on the top surface of the coarse moving X table 3.
A coarse movement Y table 4 is mounted on this linear bearing guide 7'. The coarse movement Y table 4 is coarsely fed in the direction of arrow Y along a linear bearing guide 7' by a servo motor 5' and a ball screw 6' installed on the coarse movement X table.

A fine movement X table 8 is disposed on the upper surface side of the coarse movement Y table 4, and a parallel plate spring 11 having a degree of freedom in the direction of the arrow X is straddled between the fine movement X table 8 and the coarse movement Y table 4. ing. The fine movement Y table 9 is disposed on the upper surface side of the fine movement X table 8, and a parallel plate spring 11' having a degree of freedom in the direction of the arrow Y is straddled between the fine movement Y table 9 and the fine movement X table 8.

A sample 10, such as a semiconductor wafer, is placed on the upper surface of the fine-movement Y table 9.

A magnetic block 12 is attached to the end faces of the fine movement X table 8 and the fine movement Y table 9 perpendicular to the movement direction. Electromagnets 13 and 13' are disposed at positions facing the magnetic block 12 with a gap in between. Note that the electromagnets 13 and 13' are mounted on a coarse movement Y table. The fine movement X table 8 and the fine movement Y table 9 can be slightly moved to positions where the electromagnetic force generated between the electromagnets 13 and 13' and the magnetic block 12 is balanced with the spring force of the parallel plate springs 11 and 11'. .

An optical mirror 15 is attached to the surface side of the fine movement Y table 9 in the X and Y directions. This optical mirror 15 has
For example, a laser interferometer 17 using a laser beam 16 is compatible. This detection signal is then transmitted to the controller 1.
4 is input.

Now, when the target movement amount is given to the controller 14,
First, the servo motors 5 and 5' operate, and the ball screw 6
and 6' move the coarse movement X table 3 and the coarse movement Y table 4. Next, the optical mirror 15 and the laser beam 1
The electromagnet 1? of the fine movement and 13' to move the table to the normal position. According to this K, ±0.5μm against the target value
It is known that positioning can be performed with the following accuracy.

As mentioned above, the reason why it is necessary to have a structure that combines coarse movement feed and fine movement feed is that a coarse movement table alone can only guarantee positioning accuracy of about ±2 μm to ±10 μm, and a fine movement table alone can only guarantee a positioning accuracy of about ±2 μm or ±10 μm. late,
This is also because the stroke is small. Therefore, 2
It has a two-tiered structure with a coarse movement table and a fine movement table,
As mentioned above, the structure becomes complicated. Furthermore, in order to mount the fine movement table, it is necessary to increase the rigidity of the coarse movement table, which has the disadvantage that the table becomes large and unsuitable for the size of the sample. Furthermore, as mentioned above, the two-tiered structure increases the height of the entire structure, which not only makes handling inconvenient, but also moves the center of gravity away from the drive shaft of the coarse movement table, increasing the coarse movement table error. This has the disadvantage that high-precision positioning is difficult because it is easily influenced by external vibrations and the like.

The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide a precision plane moving device having a small size and simple configuration that can position a table with high precision.

In order to achieve the above object, the present invention simplifies the four-stage structure in which a two-stage fine movement stage is mounted on a two-stage coarse movement stage as in the conventional plane moving device (Fig. 1). A table with a two-stage structure is constructed, including an X table that can be accumulated and coarsely and finely moved, and a Y table that can be coarsely and finely moved. Specifically, the present invention includes a first table that is guided in a fixed direction by a linear bearing guide provided on a base, and a first table that is guided in a direction perpendicular to the fixed direction by a linear bearing guide provided on the first table. a second table, and a linear drive means that generates a long stroke for the first table and the second table, and a linear image small displacement mechanism that generates a minute stroke, and The linear drive means can be freely connected to and disconnected from the table, which is the driven member, and the linear minute displacement mechanism can be freely connected to and disconnected from the member that supports the table, which is the displaced member. It is characterized by:

With the above configuration, the linear image small displacement mechanism is freed in each of the two orthogonal axes directions, and the linear drive means performs coarse movement to perform general positioning, and then the linear drive means is activated. Precise positioning can be performed using the linear image small displacement mechanism.

Next, a simple embodiment of the present invention will be described with reference to FIGS. 2 to 4.

20 is the base of the device, and a linear bearing guide 7 is mounted on this base.
is fixed to guide the X table 18 in the X-axis direction. A second linear bearing guide 7' is fixed onto the X-table 18 to guide the sample table 19 in the Y-axis direction. The above-mentioned linear bearing guide 7' is constructed using a static air bearing or a bearing means with less friction and stick-slip during sliding.

A servo motor 5 is attached to a base 20 to freely rotate a ball screw 6, and a block 22 is configured to be screw-fed by a nut 21 screwed onto the ball screw 6.

An arm 23 is fixed to the X-table 18 and engaged with the block 22 as described below.

(See Figure 3) A notch 23a is provided in the arm 23 fixed to the X table 18, and a tongue piece 23 having leaf spring-like elasticity
form b. Then, the block n is formed into a U-shape, and the arm 23 is gently held therebetween via the gap g.

A flang element 25 is placed inside the U-shape of the block 22.
Stick to it. This clamp element clamps the arm 23 when a voltage is applied to extend it, and when no voltage is applied, it contracts to create a gap g between it and the arm 23 and release the clamp.

In this embodiment, the above-mentioned clamp element 25 is an electrostrictive element with a stroke size of μm.

When the clamp element 25 is extended, since the tongue piece 23b has elasticity, there is no risk of damage to related members due to excessive clamping force.

In this embodiment, as described above, the linear drive means is formed by the servo motor 5°, the ball screw 6, (not shown) 21 and the block n, and the linear drive means is connected to the X table 1.
8 and can be freely combined and released.

Reference numeral 26 in FIG. 2 is a guide plate of the block 22, and a pair of guide rollers attached to the lower surface of the block n hold the guide plate 26 and support the rotational reaction force of the ball screw 6.

- 10,000, the linear image small displacement mechanism 31 is provided on the X table 18 as follows.

A slide plate 32 is fixed on the base plate, and a slide block frame is mounted on this slide plate 32. The aforementioned linear image small displacement mechanism 31 is fixed to this slide block. And the rectilinear image small displacement mechanism 31 and
A leaf spring blade is interposed between the table 18 and the table 18, and the two are brought into contact with one foot of pressure. a.

U is a leaf spring seat fixed to the X table 18.

The linear image small displacement mechanism 31 is composed of an electrostrictive element or a grinding strain element, and expands and contracts in the linear direction according to changes in the voltage and current applied thereto. In this embodiment, the linear image small displacement mechanism 31 is constructed by laminating electrostrictive elements, and when a voltage of several hundred to several thousand V is applied, a stroke of several tens of μm is obtained, and creep and hysteresis are avoided. Extremely small. This is K
Inputting a step voltage of less than IV is a trap.
A fine motion resolution of 0.01 μm level can be obtained.

An air conduit package is connected to the slide block (material) on which the linear image small displacement mechanism 31 is attached, and the controller 14
A pressure air source (not shown) or a vacuum source (not shown) is connected to a source of pressurized air (not shown) or a source of vacuum (not shown) by means of an inlet valve which is selectively activated by the switch. When the slide block (9) is connected to a pressurized air source, the slide block recess blows air downward to form a thin air layer between it and the slide plate 32, allowing it to slide freely as an air bearing. . Further, when connected to a vacuum source, it is attracted and fixed to the slide plate 32.

When the above-mentioned slide block (materials) is made to slide freely by supplying pressurized air, when the X table 18 attempts to move in the ) moves together with the X table 18 and does not resist the movement of the X table 18. Also,
When a vacuum is supplied to the slide block 32 and the slide plate 32 K IIk is attached, the X table 18
It becomes impossible to move freely in the tiX-axis direction.

When the linear minute displacement mechanism 31 expands or contracts in this state, the X table 18 is slightly moved in the X-axis direction in accordance with the expansion or contraction.

The present embodiment is configured as described above so that the linear minute displacement mechanism 31 can be freely connected to and released from the base plate, which is the X-table 180 supporting member.

The above describes the linear drive means (servo motor 5, ball screw 6, nut 21, block n, and arm 23) provided on the X table 18 guided in the X-axis direction with respect to the base 20;
And, although the linear minute displacement mechanism 31 has been described, similarly to these, the sample table 19 guided in the Y-axis direction with respect to the X table 18 is provided with a servo motor 5', a ball screw 6', a block n', etc. A linear drive means and a linear minute displacement mechanism 31' are provided.

An optical mirror 15 is mounted on the sample table 19, and a laser beam 16 is used to measure the distance in the X direction by a laser interference length measuring device 17.
Detects the position in the Y direction and sends the detected position signal to controller 1
4. This controller 14 controls the entire plane moving device, and is fed back with the position signal of the sample table as described above, and drives the servo motor 5.5.
', Clamp element section, linear minute displacement mechanism 31.31'
, and the lenoid valve 7'35, 35' to control the position of the sample table 19 as described later.

Next, regarding FIGS. 3 and 4, the X table 18 is
A control method for performing coarse movement steps in the axial direction (horizontal direction in the figure) and more precise positioning will be described.

In FIGS. 3 and 4, the position of the X table 18 is shown with reference to the position of the side 18 m.

FIG. 3 shows the state before the X-table 1B is coarsely moved to the right, and FIG. 4 shows the state after the above-mentioned coarse movement step. FIG. 4 is an explanatory diagram of the operation of finely adjusting the dimension ±ΔX as will be described later.

In the state shown in Figure 3 (before the coarse movement step), pressurized air is supplied to the slide block 30 as described above so that the slide block can freely slide on the slide grate 32. That is, the linear minute displacement mechanism 3
1 is made free with respect to the base plate which is the supporting member of the X table. An operating voltage is supplied to the clamp element section to cause it to expand. As a result, the block n clamps the arm n via the clamp element 25, and the X table 18
be combined.

In this state, the servo motor 5 is driven to turn the ball screw 6, and the block 22 is sent to the right side of the mantle 4.

Since the block 22 is holding the arm n fixed to the X table 18, the X table 18 is moved to the right. This feed 9 operation is performed with an accuracy according to the accuracy of the servo motor 5° ball screw 6 and nut, and the 10 μml
An error of i degrees is allowed.

After coarse pitch feed of # above, controller 1
．． The HC switches the renoid valve mode and operates the slide block (9) to supply a vacuum to the slide block (9) so that it is attracted to the slide plate 32. Next, the input to the clamp element section is stopped to contract the clamp element δ, and block 22
Between the arm and the j! Create a gap. - At this stage, a gap g is created between the arm n and the clamp element part. Next, the controller 14 operates the servo motor 5 to move the block 22 tg/2 to the left in the figure.

This creates a gap of g/2 at each of the two locations where arm 23 and block n face each other, resulting in the state shown in FIG. 4.

In the above state, the linear drive means consisting of the servo motor 5, the ball screw 6, the block 22, etc.
The connection with 8 is released to allow forward and backward movement of g/2 dimension.

As a result, the X table 18 is completely isolated from the effects of vibrations of the servo motor 5 and thermal expansion and contraction of the ball screw 6, making it possible to perform accurate positioning as described later.

- 10,000, In the above state, the linear minute displacement mechanism 31 slides through the slide block (equipment) Klk
The foot is fixed. And, the X table 1B is the leaf spring 3
3 and comes into contact with the linear image small displacement mechanism 31 mentioned above. Therefore, when the linear image small displacement mechanism 31 is extended, the X table 18 is directly pushed and moved to the right in the figure. Further, when the linear image small displacement mechanism 31 contracts, the X table 18 is moved to the left in the drawing while maintaining contact with the linear image small displacement mechanism 31 by the biasing force of the leaf spring blade. In this way, within the range of X table 18 g/2, ±ΔX in the X axis direction (left and right direction in the figure)
It is made to move precisely.

As mentioned above, the function of continuously performing a relatively long coarse movement step with a relatively long stroke and precision positioning of dimensional ΔX that can cover the manual positioning error of the coarse movement step is, for example, a semiconductor wafer. This is a mechanism that corrects the amount of misalignment between the wafer and the mask by finely moving the amount of misalignment between the wafer and the mask with a resolution of ±0.1/Jm or less in X# exposure equipment that transfers fine patterns of 1 μm or less onto the wafer by step-and-repeat. Very suitable for application.

The coarse movement steps in the X-axis direction and the precise positioning operations have been explained above with reference to Figures 3 and 4 (see Figure 2).
Similarly, the sample table 19 can be coarsely moved in steps in the Y-axis direction, and then precise positioning can be performed.

As explained above, the present invention provides a first series of tables (
The X table 18) in the above embodiment is provided, and a second table (sample table 19 in the previous example) guided in a direction perpendicular to the above fixed direction by a linear bearing guide provided on the first table, the first table and the second table of
For each table, a linear drive means that generates a long stroke and a linear image small displacement mechanism that generates a minute stroke are provided. - By making it releasable and also making it possible to connect and release the linear image small displacement mechanism to a member that supports the table, which is a displaced member, the table can be moved in coarse steps with a small and simple configuration. , and can perform positioning with high precision, resulting in excellent practical effects.

[Brief explanation of the drawing]

Figure j111 is a perspective view of a conventional precision plane moving device, the second
The figure is a perspective view of one embodiment of the precision plane moving device according to the present invention, and FIGS. 3 and 4 are explanatory views of the operation of the above embodiment. 5.5'...Servo motor constituting the linear drive means, 6,6'...Same ball screw, '1.7'...
Straight bearing guide, 14...controller, 18...X
Table, 19...Sample table, Addition...Base, 2
DESCRIPTION OF SYMBOLS 1...Nut constituting the linear drive means, n...Same block, 23...Arm, cram...clamp element, %...Guide plate, 1.7...Guide row 2. 30-...Slide block, 31°31'...
Straight-moving image small displacement mechanism, 32...slide plate, oh...plate spring, ah...plate spring seat, as, as'...
・Nrenoid valve, lead...air pipe. Agent Patent Attorney Tadashi Akimoto Younger brother 1 Ward

Claims (1)

[Claims] A first table guided in a fixed direction by a linear bearing guide provided on the base; and a second table guided in a direction perpendicular to the fixed direction by a linear bearing guide provided on the table of I@1. and a linear drive means that generates a long stroke and a linear minute displacement mechanism that generates a minute stroke for the @l table and the second table, respectively, and the linear drive means is covered with the linear drive means. A precision device characterized in that it can be freely connected to and disconnected from a table that is a driving member, and the linear minute displacement mechanism can be freely connected and disconnected from a member that supports a table that is a displaced member. Planar moving device.