JP2003233424A - Method and device for correcting position of xy stage, and for positioning using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize a high level of accuracy in positioning for laser machining without increasing price of a device. <P>SOLUTION: When a pattern arranges a reference mask 30 formed regularly on an XY stage 10 in advance, and the position of the XY stage is corrected based on a coordinate value acquired by photographing positions of respective patterns 32 with a camera 44, scales 20X, 20Y for measuring of a position of the XY stage are corrected by a laser measuring length, the positions of patterns arranged on prescribed lines of the reference mask 30 are obtained based on the scale for the XY stage corrected by the laser measuring length as a reference, and the coordinate value is corrected based on a scale measured value after the correction. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an XY stage position correction method and apparatus, and a positioning method using the same.
Related to the equipment, especially 300mm in laser processing system
The present invention relates to an XY stage position correction method and device suitable for use when using a large stroke XY stage exceeding 300 mm, and a positioning method and device using the same.

[0002]

2. Description of the Related Art There is known an XY stage which freely moves an object arranged on the stage in a two-dimensional direction. In order to improve the mechanical positioning accuracy with this XY stage, it is necessary to use high-precision parts, precision is required for assembly, the price becomes expensive, and the number of assembly steps increases. Have a point.

In order to solve such a problem, in JP-A-10-105242 and JP-A-7-325623, a glass mask prepared by accurately measuring the position coordinates of a pattern is used as a reference mask. Is set on the XY stage, and the XY stage is driven by an amount corresponding to the design value determined by the pattern position on the reference mask, and the error between the position of the XY stage and the pattern position marked on the reference mask at that time Then, a correction table is created from this error and stored in a storage device or the like, and when the XY stage is moved to a predetermined position, a correction amount for moving to the predetermined position is calculated from the correction table, and the calculated correction amount is calculated. Using XY
A method for obtaining the drive amount of the stage and correcting the position of the XY stage is described.

In this method, the reference mask is required to have high accuracy, and it is considered desirable to use, for example, a quartz mask so that the influence of temperature change is reduced.

[0005]

However, such a material having a low coefficient of thermal expansion is generally very expensive, and 300 mm × 30 which is particularly required in a laser processing system or the like.
When the size is 0 mm or more, the reference mask is more expensive than the price of the XY stage body. If a large number of XY stages are to be corrected, such an expensive reference mask can be used, but when performing a small amount of position correction for up to several tens of XY stages, there is a risk of damage during work. Yes, not realistic. Further, the coefficient of thermal expansion of synthetic quartz is 0.6 μm / ° C., and when the ambient temperature at which the reference mask is manufactured (for example, 17 ° C.) is different from the temperature at the correction location (for example, 23 ° C.), the temperature change There is also a problem in that the position error of is reflected in the stage position accuracy.

The present invention has been made to solve the above-mentioned conventional problems, and an object thereof is to improve the positional accuracy of the XY stage without using an expensive reference mask having a small coefficient of thermal expansion.

Further, according to the present invention, when the XY stage collides with a mechanical stopper due to a runaway or the like and the accuracy of straightness, yawing and the like deteriorates, the accuracy of the stage is promptly restored at a low cost. This is an issue.

[0008]

According to the present invention, a reference mask in which patterns are regularly formed in advance is arranged on an XY stage, and the position of each pattern is photographed by a camera, based on coordinate values obtained by When correcting the position of the XY stage, XY
The scale for measuring the position of the stage is corrected by laser length measurement, and the positions of the patterns arranged on a predetermined row of the reference mask are obtained based on the scale for XY stage corrected by the laser length measurement, and the correction is performed. The above problem is solved by correcting the coordinate value based on the subsequent scale measurement value.

Further, the laser measuring direction is made to coincide with the feeding direction of each stage to improve the correction accuracy.

Further, the inclination of the reference mask is corrected with reference to the intersection of the columns corrected by the laser length measurement, so that the correction accuracy is also improved.

The present invention also provides an XY stage position correcting apparatus for correcting the position of the XY stage using a reference mask in which patterns are regularly formed in advance.
Means for fixing the reference mask on the stage, imaging means for photographing the position of each pattern on the reference mask, laser length measuring means for correcting the scale for measuring the position of the XY stage, and the reference mask Position measuring means for obtaining the positions of the patterns arranged in a predetermined row on the basis of the scale for the XY stage corrected by the laser length measurement, and the coordinate value of each pattern obtained by the imaging means for the position measurement. And a means for correcting the scale measurement value after correction obtained by the means.

Further, the image pickup center of the image pickup means and the optical axis of the laser length measuring means are aligned with each other to improve the correction accuracy.

The present invention also provides an XY stage positioning method characterized in that the XY stage is positioned at a target position using the correction value obtained by the position correction method.

The present invention is also provided with an XY stage positioning device characterized by comprising the above position correcting device and means for positioning the XY stage using the coordinate values corrected by the position correcting device. Is provided.

The present invention also provides a processing method characterized by using the above-mentioned positioning method to perform positioning of an object to be processed arranged on an XY stage.

The present invention also comprises the above-mentioned positioning device, means for fixing an object to be processed on the XY stage positioned by the positioning device, and means for processing the object to be processed on the XY stage. The present invention provides a processing device characterized by the above.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings.

In this embodiment, FIG. 1 (front view) and FIG.
As shown in (plan view) and FIG. 3 (perspective view of main parts), a Y stage 12Y driven by a Y axis motor 14Y in the Y axis direction (vertical direction in FIG. 2), and arranged on the Y stage 12Y. , An X stage 12X driven by the X axis motor 14X in the X axis direction (left and right direction in FIGS. 1 and 2), and a suction table 16 for fixing the object to be processed and the reference mask 30 on the X stage 12X. The target is the XY stage 10.

The X stage 12X and Y stage 12
Each Y has a linear scale 20X, as shown in FIG.
20Y is arranged, X stage 12X or Y stage 1
2Y side fixed scale body 22X, 22Y, Y
By the relative displacement of the scanning units 24X and 24Y fixed to the stage 12Y or the base 18 side, each stage 12
The position of each of the X and 12Y axes (X axis and Y axis) is measured. In the figure, 26X and 26Y are cables.

The reference mask 30 is made of a relatively inexpensive glass such as soda lime that is generally used, and as shown in FIG. 4, for example, a position detection pattern which is regularly arranged on the squares of a grid. The use mark 32 is drawn. The absolute position accuracy of each mark 32 is preferably as high as possible, and is, for example, 3 μm or less. The coefficient of thermal expansion of soda lime, which is a general glass component, is 8.5 μm / ° C., and the positional accuracy of the position detection marks 32 is greatly affected by temperature changes, but the straightness of the arrangement of the marks 32 is , It does not change even if the temperature changes.

As shown in FIG. 1, above the XY stage 10, as a camera observation system, an illumination device 40, a camera 44 for taking an image of the mark 32 of the reference mask 30 via a lens 42, and the camera 44. An image processing device 46 for processing the image acquired by 44 to obtain the position of each mark 32, and a personal computer (PC) 48 for displaying the image processing result by the image processing device 46 on the monitor 50 are provided.

Here, the correction accuracy is improved by installing the camera observation system coaxially with the laser optical axis and performing the correction, but the camera may be installed at a position different from the laser optical axis to perform the correction. Absent. In that case, the correction accuracy tends to deteriorate as the distance from the optical axis increases.

The illuminating device 40 may be a ring illuminator or a coaxial illuminator as long as the illuminating method does not interfere with the image processing detection of the position detection mark 32.

The positioning of the XY stage 10 is performed as shown in FIG.
It is desirable to use a full-closed control system having linear scales 20X and 20Y and servomotors 14X and 14Y as shown in FIG. 3, and the pitch error correction is performed by laser measurement to correct the positioning accuracy in the axial direction. Specifically, a comparison table of the measured values by the linear scales 20X and 20Y and the values measured by the laser measurement is created on a computer, and the stage 1 is based on the values measured by the laser measurement.
Linear scales 20X, 2 so that 2X, 12Y move
Feedback control is applied through 0Y.

As shown in FIG. 2, the axis corrected in the stroke direction by laser length measurement is used as a reference axis for correction by the reference mask 30. The correction accuracy is improved when the reference axis passes through the processing point 19 by laser processing.

Therefore, the XY stage 10 is further provided with, for example, a laser length measuring device 60 by interference as illustrated in FIG. 5, and the feeding direction of the X stage 12X passing through the processing point 19 shown in FIG. 2 ( The position in the X-axis direction and the position in the feed direction (Y-axis direction) of the Y stage 12Y can be measured with high accuracy. In FIG. 5, reference numeral 62 is a movable side mirror that is configured to move together with the XY stage 10.

Here, the laser beam emitted from the laser length measuring device 60 is the beam splitter 66 and the fixed side mirror 6.
The laser length measuring device 6 is reflected by the movable side mirror 62 via
To return to 0, the laser length measuring device 60 obtains the distance x between the movable side mirror 62 and the fixed side mirror 68, that is, the distance in the X-axis direction of the XY stage 10, from the relationship between the irradiation light and the reflected light.
Further, the laser beam emitted from the laser length measuring device 60 is reflected by the movable side mirror 62 via the beam splitter 66 and the fixed side mirror 70 and returns to the laser length measuring device 60. Fixed side mirror 70 and movable side mirror 6
The distance y between the two is detected to obtain the distance of the XY stage 10 in the Y-axis direction.

A specific processing procedure will be described below with reference to FIG.

First, in step 100, the XY stage 10
The reference mask 30 is placed on the top and fixed by the suction table 16 or a jig. At this time, the inclination between the reference mask pattern axis and the stage axis is made as small as possible so that the pattern can be detected within the visual field of the camera 44 at the beginning and end of the correction range.

Next, in step 102, the patterns at the four corners of the reference mask 30 are viewed by the camera 44, the pattern coordinates are measured, and the inclination of the reference mask pattern axis with respect to the stage axis is calculated. As shown in FIG. 7, when the XY stage 10 has a rotatable θ stage 15, the reference mask 30 is rotated by the θ stage 15 so that the pattern axis of the reference mask 30 is parallel to the stage axis. Can be corrected to

Next, in step 104, the reference masks 30 are fed line by line in the X-axis direction and the Y-axis direction at a predetermined pitch (for example, 1 to 5 times the pattern pitch), and the position detection marks arranged in a grid pattern. When 32 is viewed with the camera 44, coordinate values are obtained by image processing, and for the pattern on each reference axis, the length measurement value by the laser length measuring device 60 is also obtained.

Next, in step 106, the coordinate error due to the inclination of the reference mask 30 is removed from the obtained coordinates by calculation. At this time, the error due to the inclination is calculated with the intersection point of the column on which the X-axis laser length measurement is performed and the column on which the Y-axis laser length measurement is performed as a reference (0, 0).

As a result, in step 108, the primary correction map, which is a set of correction values in the X and Y axis directions at each grid point in the stroke range to be corrected, is completed. This primary correction map is basically the same as in Japanese Patent Laid-Open No. 10-10524.
2 and the one created by JP-A-7-325623.

Next, in step 110, the X component is corrected by the value obtained by the laser length measuring device 60. Specifically, X1 of the data (X1, YL) shown in FIG. 8 is changed to X1L obtained by laser measurement, and (X1, Y1)
(X1-X1L) is added to X1 of (X1, YN). Similarly, the X component of each grid point is corrected.

Next, in step 112, the data (X
Y1 of (L, Y1) is changed to a value Y1L obtained by laser measurement, and Y1 of (X1, Y1) to (XN, Y1) is changed to (Y1-Y1L).
Is added. Similarly, the Y component of each grid point is corrected.

In this way, the secondary correction map completed in step 108 is completed by correcting the primary correction map completed in step 108 based on the laser length measurement correction.

When the XY stage 10 is moved to a predetermined position, the procedure shown in FIG. 9 is used.

That is, first, at step 200, the movement amount (target value) of the XY stage 10 is input.

Next, at step 202, from the secondary correction map as shown in FIG. 8, as shown in FIG. 10, four neighboring points A, B, C, D surrounding the point (X, Y) to be moved. Take out the correction data of.

Next, in step 204, the correction amount at the target position (X, Y) is calculated by keystone correction (trapezoidal correction) as shown in FIG. Is added, and in step 208, the XY stage 10 is moved to a position including the correction amount.

At this time, the narrower the measurement pitch (correction pitch), the more accurate the correction becomes.

In this way, for example, 300 mm × 30
Even when a large stroke XY stage exceeding 0 mm is used in the laser processing system, the processing position accuracy can be improved without using an expensive high precision XY stage or a correction method.

When the XY stage collides with a mechanical stopper due to runaway or the like, the accuracy of straightness and yawing deteriorates, and it takes time and cost to correct this by repairing the stage. It takes both, but as shown in the present invention, by performing the position correction again using the reference mask, the absolute position accuracy can be easily set to a constant value (for example, ± 2 μm).
m to ± 5 μm).

In the above embodiment, the present invention is
Although the present invention has been applied to the laser processing system, the application target of the present invention is not limited to this, and it is obvious that the present invention can be applied to other processing machines and other processing machines as well.

The means for detecting the position of the XY stage is not limited to the linear scale, but may be a rotary encoder for detecting the rotation of the stage feed shaft, for example.

[0046]

According to the present invention, high positioning accuracy can be realized without increasing the cost of the device.
Further, by the correction, stable accuracy can be obtained for each product. Furthermore, even if the accuracy of the XY stage is once degraded, it is possible to recover the stage accuracy relatively easily and quickly by performing remeasurement and correction by software without physically correcting it. .

[Brief description of drawings]

FIG. 1 is a front view showing the overall configuration of an embodiment according to the present invention.

FIG. 2 is a plan view of the XY stage.

FIG. 3 is a perspective view of the same.

FIG. 4 is a plan view of the reference mask.

FIG. 5 is a perspective view showing a configuration of laser measurement similarly.

FIG. 6 is a flow chart showing a correction map creating procedure.

FIG. 7 is a perspective view showing a modified example of the XY stage.

FIG. 8 is a chart showing an example of a correction map according to an embodiment of the present invention.

FIG. 9 is a flow chart showing a procedure for calculating a position correction amount.

FIG. 10 is an explanatory diagram showing a method of calculating a correction position in the same manner.

[Explanation of symbols]

10 ... XY stage 12X ... X stage 12Y ... Y stage 14X ... X-axis motor 14Y ... Y-axis motor 16 ... Suction table 19 ... Processing point 20X, 20Y ... Linear scale 30 ... Reference mask 32 ... Position detection mark 40 ... Lighting device 44 ... Camera 46 ... Image processing device 38 ... Personal computer (PC) 50 ... Monitor 60 ... Laser length measuring device

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 2F065 AA03 AA06 BB27 FF04 FF51                       GG04 HH04 HH13 LL12 PP12                 2F078 CA08 CB06 CB12 CC01                 5H303 AA01 BB02 BB07 BB12 CC02                       DD01 EE03 EE09 FF08 FF13                       GG13 HH02 HH07 LL03

Claims (9)

[Claims] 1. When correcting a position of an XY stage based on coordinate values obtained by arranging a reference mask on which patterns are regularly formed on an XY stage and capturing the position of each pattern by a camera. In addition, the scale for measuring the position of the XY stage is corrected by laser length measurement, and the positions of the patterns arranged on a predetermined row of the reference mask are obtained based on the scale for the XY stage corrected by the laser length measurement. A position correction method for an XY stage, characterized in that the coordinate values are corrected based on the scale measurement values after the correction. 2. The position correction method for an XY stage according to claim 1, wherein the laser length measurement direction is made to coincide with the feed direction of each stage. 3. The position correction method for an XY stage according to claim 1, wherein the inclination of the reference mask is corrected with reference to the intersection of the columns corrected by the laser measurement. 4. An XY for correcting the position of an XY stage using a reference mask in which a pattern is regularly formed in advance.
In a stage position correction device, means for fixing a reference mask on an XY stage, imaging means for photographing the position of each pattern on the reference mask, and laser measurement for correcting the scale for measuring the position of the XY stage. Length measuring means, position measuring means for obtaining the positions of the patterns arranged in a predetermined row on the reference mask with the scale for the XY stage corrected by the laser length measurement as a reference, and each pattern obtained by the imaging means. A position correcting device for an XY stage, comprising: a means for correcting the coordinate value of 1. based on the scale measurement value after correction obtained by the position measuring means. 5. The position correcting device for an XY stage according to claim 4, wherein an image pickup center of said image pickup means and an optical axis of said laser length measuring means are aligned with each other. 6. A positioning method for an XY stage, characterized in that the XY stage is positioned at a target position using the correction value obtained by the position correction method according to claim 1. 7. An XY stage comprising: the position correction device according to claim 4; and means for positioning the XY stage using the coordinate values corrected by the position correction device. Positioning device. 8. The positioning method according to claim 6,
A processing method characterized by positioning a processing target placed on an XY stage. 9. The positioning device according to claim 7, a means for fixing an object to be processed on an XY stage positioned by the positioning device, and a means for processing an object to be processed on the XY stage. A processing device characterized by being provided.