JPH07135155A - Stage device - Google Patents

Abstract

PURPOSE:To effectively detect the variations of the two-dimensional coordinate system of a stage during the actual application in a stage device. CONSTITUTION:A reference mark 14 is arranged on a stage 11 to be detected by at least three each or mark detecting means 12A-12C arranged in a specific positional relation on the second two-dimensional coordinate system wherein the variations of the first two-dimensional coordinate system are corrected. Through these procedures, the relations between the variations alpha, beta and the previously set up corrected values can be detected if necessary by calculating the variations alpha, beta as the first and second two-dimensional systems coordinate according to the measurement results of the positional measuring means 13X, 13Y as well as the specific positional relations of the mark detecting means 12A-12C when the reference mark 14 is detected by the coordinate variation measuring means.

Description

Detailed Description of the Invention

[0001]

【table of contents】

 The present invention will be described in the following order. Industrial Application Conventional Technology (FIGS. 5 and 6) Problem to be Solved by the Invention (FIGS. 5 and 6) Means for Solving the Problem (FIG. 1) Action (FIG. 1) Embodiment (FIG. 1) ~ Fig. 4) Effect of the invention

[0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stage apparatus, and is suitable for application to an XY stage in an exposure apparatus for semiconductor manufacturing or liquid crystal display manufacturing, for example.

[0003]

2. Description of the Related Art Conventionally, positioning of an XY stage in an exposure apparatus is performed by fixing two plane mirrors to the XY stage so as to form a right angle with each other, irradiating the two plane mirrors with a light beam, and reflecting the reflected light of the light beam. Positioning is performed by measuring the distance to the plane mirror. In this case, the X axis and the Y axis of the Cartesian coordinate system of the XY stage determined by the two plane mirrors may not be completely orthogonal to each other due to a mounting error of the two plane mirrors. In such a state, when the pattern on the reticle is exposed on the substrate placed on the XY stage, the pattern is exposed from the original position.

In order to correct such positioning error of the XY stage, conventionally, as shown in the exposure procedure SP1 of FIG. 5, a test exposure is first performed to measure the orthogonality of the coordinate system of the XY stage (step SP1). ), The orthogonality obtained as a result is set as a correction value (step SP2), and the exposure operation is performed (step SP3). In practice, in this test exposure, as shown in FIG. 6, the substrate 2 placed on the XY stage 1 is placed on the X-axis, Y-axis of the XY stage 1.
The substrate 2 is developed by exposing the substrate 2 for a few shots in parallel with the axis, and then rotated by 90 ° from the first exposure and placed on the XY stage 1.

Subsequently, the substrate 2 in the X-direction, the Y-direction, and the rotation (θ) direction is used by using one X-direction positioning mark and two Y-direction positioning marks in the shot exposed during the first exposure. After alignment, the substrate is exposed to the same shutter position as the first exposure, and the substrate 2 is developed.

After that, by reading the vernier in the X direction in the shot of the first exposure (shown by the broken line in the figure) and the second exposure (shown by the solid line in the figure), the first and second intervals of the interval L are read. The shift amounts X _A and X _B in the X direction of the exposure shot position are calculated by the following equation using the shift amounts X _A and X _B.

[Equation 1] To obtain the orthogonality α of the Y axis with respect to the X axis approximately,
The exposure operation is performed using the orthogonality α as a correction value. Incidentally, the deviation amount X _A, X _B is for one round of Shiyotsuto position, Shiyotsuto position for the second time is a positive if shifted in the -X direction. The orthogonality α is positive in the counterclockwise direction.

[0007]

However, in the method in which the orthogonality α is previously measured by the test exposure and the correction value is set based on the measurement result, the temperature change and the temperature change after the correction value itself is determined. There is a problem in that it is not possible to deal with the case where the orthogonality of the coordinate system of the XY stage 1 changes due to some cause such as a shock during maintenance.

The present invention has been made in consideration of the above points, and it is an object of the present invention to propose a stage device which can effectively detect a change in the orthogonal coordinate system of the stage when the stage is actually used.

[0009]

In order to solve such a problem, according to the present invention, a stage 11 that can move two-dimensionally in a plane and a stage 11 using a first two-dimensional coordinate system in the plane.
Position measuring means 13X, 13Y, 15 for measuring the position of
In a stage device that has X and 15Y and is used by correcting the change amount of the first two-dimensional coordinate system with a predetermined correction value,
The reference mark 14 placed on the stage 11 and the second two-dimensional coordinate system in which the amount of change of the first two-dimensional coordinate system is corrected are placed in a predetermined positional relationship, and the reference mark 14
At least three mark detecting means 12A-1 for detecting
2C and the reference mark 14 are mark detection means 12A to 12C.
Position measuring means 1 when detected by each of C
Based on the measurement results of 3X, 13Y, 15X, and 15Y and the predetermined positional relationship of the mark detecting means 12A to 12C,
A coordinate change amount measuring means for determining the change amounts α and β of the first two-dimensional coordinate system with respect to the second two-dimensional coordinate system is provided.

In the present invention, the first two-dimensional coordinate change amounts α and β measured by the coordinate change amount measuring means.
Then, a notification means is provided to notify the operator when the difference from the preset correction value exceeds a predetermined value.

In the present invention, the first two-dimensional coordinate change amounts α, β measured by the coordinate change amount measuring means.
Then, when the difference from the preset correction value exceeds a predetermined value, the change amount is used as the correction value.

Further, in the present invention, the coordinate change amount measuring means uses the change amount of the first two-dimensional coordinate system with respect to the second two-dimensional coordinate system as the orthogonality α of the stage, the rotation deviation amount β of the stage, and the stage rotation amount β. The expansion and contraction and / or the shift of the origin of the stage were measured.

[0013]

The reference mark 14 is arranged on the stage 11, and the reference mark 14 is arranged in a predetermined positional relationship on the second two-dimensional coordinate system in which the amount of change of the first two-dimensional coordinate system is corrected. Based on the measurement result of the position measuring means 13X and 13Y at the time of detecting the reference mark by the coordinate change amount measuring means and the predetermined positional relationship of the mark detecting means 12A to 12C. The change amount α of the first two-dimensional coordinate system with respect to the second two-dimensional coordinate system,
By determining β, the relationship between the change amounts α and β of the orthogonal coordinate system of the stage 11 and the preset correction value can be measured when the stage 11 is used, if necessary.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings.

In FIG. 1, reference numeral 10 denotes an exposure apparatus to which the stage device according to the present invention is applied as a whole, and an XY stage 11 on which an exposure substrate is placed and three XY positions arranged in an ideal orthogonal coordinate system. Detection sensors 12A, 12
B and 12C are included. Of the three XY position detection sensors 12A, 12B, 12C, the first and second
Between the position detection sensors 12A and 12B, and the distance B between the first and third position detection sensors 12A and 12C.
12Cs are arranged so that they do not overlap each other.

On the XY stage 11, two plane mirrors 13X and 13Y for positioning using laser interferometers 15X and 15Y are fixed at right angles to each other, and XY position detecting sensors 12A, 12B and 12C are provided. Thus, for example, a lattice-shaped reference mark 14 that is detected is formed. The XY stage is a plane mirror 13X, 13Y.
The laser interferometers 15X and 15Y move while detecting the position in the XY coordinate system (first two-dimensional coordinate system).

The XY position detecting sensors 12A, 12B,
12C is arranged based on a two-dimensional coordinate system (a second two-dimensional coordinate system, which is a postoperative X'Y 'coordinate system) in which the orthogonality obtained in advance by test exposure is corrected, and the laser is provided. The light is emitted vertically downward and the diffracted light by the reference mark 14 is detected by the detector. As a result, the XY stage 11 is moved to scan the reference mark 14 with respect to the laser light, and it is detected that the reference mark 14 exists directly below the sensor based on the peak of the detector output.

In the case of this embodiment, the XY coordinate values obtained from the laser interferometers 15X and 15Y and the XY position detecting sensors 12A and 12 when the reference mark 14 is located directly below.
By comparing the XY coordinate values according to the positions of B and 12C, the orthogonality of the XY stage 11 and the amount of rotation deviation can be measured.

That is, as shown in FIGS. 2 and 3, XY
When measuring the orthogonality of the coordinate system of the stage 11 and the amount of rotation deviation, the two plane mirrors 13X and 13Y on the XY stage 11 are measured.
Y with respect to the X axis of the XY Cartesian coordinate system determined by
The degree of orthogonality of the axes is α, and the amount of rotational deviation of the X and Y axes is β. The orthogonality α and the rotation deviation amount β are positive in the counterclockwise direction. In addition, three XY position detection sensors 12A, 12
An ideal X'Y 'Cartesian coordinate system with an orthogonality of 0 is determined by B and 12C.

To obtain the orthogonality α of the XY orthogonal coordinate system,
First, the XY stage 11 is moved to move the reference mark 14 to the X position.
The point P1 (x1, x1 within the detection range of the Y position detection sensor 12A,
y1) and move to X'Y 'with the XY position detection sensor 12A.
The position of the point P1 in the Cartesian coordinate system is measured.

Next, the XY stage 11 is moved to move the reference mark 14 in the + X direction by the distance A between the XY position detecting sensors 12A and 12B, and the XY position detecting sensor 12B.
Is placed at a point P2 (x2, y1) within the detection range of X, and the XY position detection sensor 12B causes the point P2 in the X'Y 'orthogonal coordinate system.
Measure the position of.

Subsequently, the XY stage 11 is moved to return the reference mark 14 to the position of the point P1, and this time, it is moved in the + Y direction by the distance B between the XY position detecting sensors 12A and 12C, and the detection range of the XY position detecting sensor 12C. Point P3
It is placed at (x1, y2) and the position of the point P3 in the X'Y 'orthogonal coordinate system is measured by the XY position detecting sensor 12C.

At this time, the displacement in the Y ′ direction when the reference mark 14 is moved from the point P1 to P2 is ΔY, and the displacement in the X ′ direction when the reference mark 14 is moved from the point P1 to the point P3 is ΔX.
Then, the orthogonality α of the coordinate system of the XY stage 11 is given by

[Equation 2] Is approximately represented by.

That is, when the orthogonal coordinate system of the XY stage 11 has only the orthogonality α with respect to the ideal orthogonal coordinate system of the XY position detecting sensors 12A to 12C, FIG.
The positional relationship is as shown in, and the orthogonality α is

[Equation 3] In the case where the Cartesian coordinate system of the XY stage 11 has only the rotation deviation amount β with respect to the ideal Cartesian coordinate system of the XY position detection sensors 12A to 12C,
The positional relationship is as shown in FIG.

[Equation 4] Is approximately represented by, and thus the orthogonality α and the rotation deviation amount β of the orthogonal coordinate system of the XY stage 11 are obtained.

Actually, in the case of the exposure apparatus of this embodiment, FIG.
Exposure is performed by the exposure procedure SP10 as shown in FIG. 1, and the orthogonality of the orthogonal coordinate system of the XY stage 11 is first measured by the test exposure described above (step SP10), and the value is corrected. (Step SP11). Then, before the exposure, the orthogonality is measured using the XY position detecting sensors 12A to 12C (step S
P12), if the difference between the value of the orthogonality α and the correction value obtained as a result does not exceed the allowable value (step SP13), the exposure process is performed as it is (step SP14).

On the other hand, when the difference between the value of the orthogonality α obtained by using the XY position detecting sensors 12A to 12C and the correction value exceeds the allowable value (step SP13), the exposure apparatus equipped with the stage 11 is equipped with the same. Display a warning message on the CRT (not shown) (step SP1)
5), the obtained orthogonality α is reset as a new correction value (step SP16), and exposure is performed (step S).
P14).

According to the above configuration, the position of the reference mark 14 fixed on the XY stage 11 before exposure is set to three XY position detecting sensors 1 arranged in an ideal rectangular coordinate system.
The orthogonality α of the XY stage 11 is obtained by measuring at 2A to 12C, and when this value α is different from a preset correction value, a warning is issued and the obtained orthogonality α is set as a new correction value. As a result, it is possible to realize an exposure apparatus that can perform a normal exposure operation even when the orthogonality largely changes after the correction value is set by the test exposure for some reason.

In the above-mentioned embodiment, the case where the number of XY position detecting sensors is selected is three.
The number of sensors is not limited to this, and three or more XY position detection sensors may be used as long as at least three sensors are not arranged on the same straight line in a predetermined orthogonal coordinate system. By doing so, the detection accuracy can be further improved.

Further, in the above-described embodiment, as the XY position detecting sensor, one which irradiates the laser beam to the lattice mark formed on the XY stage and receives the diffracted light to detect the position is used. However, the XY position detection sensor is not limited to this, and the above-described implementation may be performed by using an XY position detection sensor that images a mark on a straight line on the XY stage with a CCD camera and detects the position by image processing. The same effect as the example can be realized.

Further, in the above-mentioned embodiment, when the orthogonality measured by using the XY position detection sensor is different from the correction value set by the test exposure in advance, the warning message is displayed on the CRT of the exposure apparatus. However, the warning display is not limited to this. For example, an alarm may be sounded or a warning light may be turned on. In short, if the operator can be notified, the same effect as the above-described embodiment can be realized.

Further, in the above-mentioned embodiment, the case where the orthogonality of the orthogonal coordinate system of the XY stage and the amount of rotation deviation are detected by using the XY position detecting sensor has been described. However, the present invention is in addition to this. The present invention can be widely applied to the case of detecting various changes such as expansion / contraction of the distance and shift of the origin, and in this case, the same effect as that of the above-described embodiment can be realized.

Furthermore, in the above-described embodiment, the stage device according to the present invention is used as an X in an exposure apparatus for semiconductor manufacturing.
Although the present invention is applied to the Y stage, the present invention is not limited to this.
The orthogonality is suitable for wide application to a stage device in a precision machine tool such as a milling machine to detect a change in the orthogonal coordinate system of the stage device itself such as a rotation deviation.

[0033]

As described above, according to the present invention, the position of the reference mark fixed on the stage is measured by three or more XY position detecting sensors arranged in an ideal rectangular coordinate system. , Calculate the amount of change in the Cartesian coordinate system of the stage,
If this change amount is different from the preset correction value, the operator is notified and the calculated change amount is set as a new correction value, so that the two-dimensional coordinate system of the stage can be changed when the actual stage is used. A stage device capable of effectively detecting a change can be realized.

[Brief description of drawings]

FIG. 1 is a schematic plan view showing an arrangement of an XY stage and an XY position detection sensor in an exposure apparatus as an example of a stage device according to the present invention.

FIG. 2 is a schematic diagram showing the principle of measuring the orthogonality of the orthogonal coordinate system of the XY stage.

FIG. 3 is a schematic diagram showing the principle of measuring the amount of rotational deviation of the Cartesian coordinate system of the XY stage.

FIG. 4 is a flow chart showing an exposure procedure of an exposure apparatus using a stage device according to the present invention.

FIG. 5 is a flow chart for explaining an exposure procedure of a conventional exposure apparatus.

FIG. 6 is a schematic diagram showing the principle of measuring the orthogonality of the orthogonal coordinate system of the XY stage by test exposure.

[Explanation of symbols]

1, 11 ... XY stage, 2 ... Substrate, 12A, 12
B, 12C ... XY position detection sensor, 13X, 13Y ...
... Plane mirror, 14 ... Reference mark, 15X, 15Y ... Laser interferometer.

Claims (4)

[Claims] 1. A first two-dimensional coordinate system, comprising: a stage capable of two-dimensional movement in a plane; and position measuring means for measuring the position of the stage in a first two-dimensional coordinate system in the plane. A stage device that corrects a change amount of a system with a predetermined correction value and uses the reference mark arranged on the stage, and a second mark in which the change amount of the first two-dimensional coordinate system is corrected.
At least three mark detecting means that are arranged in a dimensional coordinate system in a predetermined positional relationship and that detect the reference mark, and the position when the reference mark is detected by each of the mark detecting means. Based on the measurement result of the measuring means and the predetermined positional relationship of the mark detecting means,
A stage apparatus comprising: a coordinate change amount measuring means for obtaining a change amount of the first two-dimensional coordinate system with respect to the second two-dimensional coordinate system. 2. The operator is notified when the difference between the change amount of the first two-dimensional coordinate measured by the coordinate change amount measuring means and a preset correction value exceeds a predetermined value. The stage device according to claim 1, further comprising an informing unit. 3. When the difference between the change amount of the first two-dimensional coordinate measured by the coordinate change amount measuring means and a preset correction value exceeds a predetermined value, the change amount is set to a predetermined value. The stage device according to claim 1 or 2, wherein the stage device is used as a correction value. 4. The coordinate change amount measuring means is the first 2
As the amount of change of the two-dimensional coordinate system with respect to the second two-dimensional coordinate system, the degree of orthogonality of the stage, the amount of rotation deviation of the stage, the expansion and contraction of the stage, and / or the cyst at the origin of the stage are measured. The stage device according to claim 1, 2, or 3, which is characterized.