JP2007156232A - Exposure equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an exposure apparatus capable of accurately detecting the position of a rotating shaft at the time of exposure with an inexpensive apparatus.
A half mirror 13, a magnifying optical system 14, and a two-dimensional CCD sensor 15 (imaging means) are mounted on a support base 10. A circular pattern is formed near the rotation center of the sample 7. The illumination light from the illumination device 16 illuminates the surface of the sample 7 including this circular pattern through the half mirror 13. The light reflected by the surface of the sample 7 is reflected by the half mirror 13 and enters the magnifying optical system 14 and is magnified to form an image of the surface of the sample 7 on the imaging surface of the CCD sensor 15. Therefore, if the output of the CCD sensor 15 is processed, the position of the circular pattern can be detected, and from this, the position of the rotation axis at the time of exposure can be detected.
[Selection] Figure 1

Description

  The present invention relates to an exposure apparatus mainly used in a lithography process when manufacturing a master disk of an optical disk such as a DVD or a magnetic disk such as a hard disk.

  In a lithography process when manufacturing a substrate having a circular pattern or a spiral pattern such as an optical disk and a magnetic disk, an exposure apparatus (laser exposure apparatus, electron beam) that places a sample on a rotary table and performs patterning while rotating the rotary table. In many cases, an exposure apparatus is used. In recent years, as the demand for large-capacity storage elements has increased, the demand for finer patterning and exposure position accuracy of these exposure apparatuses has increased, and the accuracy of several nanometers has been required for exposure position accuracy. Yes.

  In order to meet such requirements regarding positional accuracy, a method of measuring a mirror position with an interferometer by installing a circular mirror on a rotary table is generally used (for example, Japanese Journal of Applied Physics, Vol. 43, No. 7B, 2004, pp. 5068-5073, Non-Patent Document 1). By measuring the position of the mirror, the position of the rotation axis is measured, and the exposure position is adjusted in accordance with it, so that an accurate circular pattern and spiral pattern can be exposed.

  An exposure apparatus for patterning a substrate on a normal XY stage has also been announced (for example, Japanese Journal of Applied Physics, Vol. 41 (2002), pp. 1714-1716, Part 1, No. 3B, March 2002, non-patent) Reference 2), there is a problem that it takes time for exposure.

Japanese Journal of Applied Physics, Vol. 43, No. 7B, 2004, pp. 5068-5073 Japanese Journal of Applied Physics, Vol. 41 (2002), pp. 1714-1716, Part1, No. 3B, March 2002

  However, in an exposure apparatus using a rotary table, it is very difficult to manufacture an accurate circular mirror by installing a circular mirror on the rotary table and measuring the mirror position with an interferometer (the error from the perfect circle is It is difficult to make it less than about 500 nm), there are problems such as the inability to separate the positional deviation of the mirror in the X and Y directions and the rotational axis, and the high number of axes of the interferometer. It is very difficult to achieve position accuracy at a low cost.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide an exposure apparatus that can accurately detect the position of the rotating shaft at the time of exposure with an inexpensive apparatus.

  A first means for solving the above-mentioned problem is an exposure apparatus for patterning a micro pattern on a sample on a rotary table while rotating the rotary table, and is near the rotation center of the sample or on a rotating body. A measuring device that includes an imaging unit that images a circular pattern formed in the vicinity of the rotation axis, and that measures a deviation amount of the rotation axis position from the position of the circular pattern imaged by the imaging unit during rotation of the rotary table; It is an exposure apparatus characterized by having.

  The second means for solving the problem is an exposure apparatus for patterning a micro pattern on the sample on the rotary table while rotating the rotary table, and is near the rotation center of the sample or on the rotating body. An optical system for enlarging and forming an image of a circular pattern formed near the rotation axis on the multi-division sensor, and the output of the multi-division sensor obtained during the rotation of the rotary table, the rotation axis position shift An exposure apparatus having a measuring device for measuring an amount.

  The third means for solving the problem is the first means or the second means, wherein the imaging means or the multi-divided sensor and the optical system are mounted with the rotary table. It is characterized by being mounted on a linear stage.

  A fourth means for solving the problem is any one of the first means to the third means, and based on the amount of deviation of the rotational axis position measured by the measuring device, the minute pattern It has a function of correcting the patterning position.

  ADVANTAGE OF THE INVENTION According to this invention, the position of the rotating shaft at the time of exposure can be provided with an inexpensive apparatus, and can detect correctly.

  Hereinafter, an example of an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a view showing an outline of an exposure apparatus according to the first embodiment of the present invention. A linear stage 2 is provided on the base 1 and is driven by a motor 3 and a feed screw 4. The linear stage 2 has two stages and is driven in the XY directions. A rotary stage 5 is provided on the linear stage 2, and the sample stage 6 is rotated by the rotary stage 5. A sample 7 (blank disk or the like) for forming a pattern is placed on the sample stage 6, and the exposure light 8 for drawing is irradiated on the surface of the sample 7 while rotating the rotary stage 5, and the linear stage 2 is uniaxially moved. While driving, patterning is performed on the surface of the sample 7 to form a circular pattern, a spiral pattern, or the like.

  Although the position of the linear stage 2 is measured by the interferometer 9, in the present embodiment, the movable mirror 11 is attached to the support 10 provided on the linear stage 2, and the laser beam of the interferometer 9 is attached thereto. The position is measured by irradiating 12.

  A half mirror 13, a magnifying optical system 14, and a two-dimensional CCD sensor 15 (imaging means) are mounted on the support base 10. A circular pattern is formed near the rotation center of the sample 7 as will be described later. The illumination light from the illumination device 16 illuminates the surface of the sample 7 including this circular pattern through the half mirror 13. The light reflected by the surface of the sample 7 is reflected by the half mirror 13 and enters the magnifying optical system 14 and is magnified to form an image of the surface of the sample 7 on the imaging surface of the CCD sensor 15. Therefore, if the output of the CCD sensor 15 is processed, the position of the circular pattern can be detected. The “near the rotation axis center” may be an area where the circular pattern can be illuminated uniformly and the image position can be measured by the sensor in the vicinity of the rotation axis center.

  FIG. 2 shows a circular pattern formed on the sample 7 and an image of the CCD sensor 15. (A) shows the circular pattern formed in the sample 7, and when the center of the circular pattern does not coincide with the rotational center of the rotational axis of the rotary stage 5, the circular pattern is formed around the rotational axis. Rotate with the deviation amount as the radius. That is, when observed with the CCD sensor 15, as shown in (b), the circular pattern image is observed to rotate around the reference point. If the center of the circular pattern coincides with the rotation center of the rotation axis of the rotary stage 5, the position of the circular pattern image observed by the CCD sensor 15 is unchanged as shown in (c). . By utilizing this fact, it is possible to measure the shift amount of the rotational axis position.

  In any case, if the position of the exposure axis of the exposure light 8 for drawing is changed in accordance with the change in the center position of the observed circular pattern, the sample 7 is not moved unless the linear stage 2 is moved. The drawing locus at is a circle centered on the center position of the circular pattern. Therefore, even when the center of the sample 7 is not aligned with the rotation center or the rotation axis is decentered, the position of the exposure axis of the drawing exposure light 8 varies according to the variation of the center position of the observed circular pattern. By doing so, it is possible to perform accurate circular and spiral drawing on the assumption that the sample 7 is rotated around the center position of the circular pattern. This is nothing but to correct the patterning position on the surface of the sample 7 based on the measured deviation amount of the rotational axis position.

  FIG. 3 is a view showing an outline of an exposure apparatus according to the second embodiment of the present invention. In this embodiment, since the CCD sensor 15 in FIG. 1 is merely changed to a four-split optical sensor 17, the other parts are denoted by the same reference numerals as those in FIG.

  The image of the surface of the sample 7 is enlarged by the magnifying optical system 14 and formed on the surface of the quadrant optical sensor 17. FIG. 4 shows the relationship between the quadrant optical sensor 17 and a circular pattern image. When the center of the circular pattern does not coincide with the rotation center of the rotation axis of the rotary stage 5, the circular pattern image is observed to rotate around the reference point as shown in (a). If the center of the circular pattern coincides with the rotation center of the rotation axis of the rotary stage 5, the position of the image of the circular pattern observed by the quadrant optical sensor 17 remains unchanged as shown in (c). It is.

  Assuming that the horizontal direction of the paper surface is the X direction and the vertical direction is the Y direction, the position of the center of the circular pattern in the X direction is {(first quadrant output + fourth quadrant output)-(second quadrant output + third quadrant output). }, And the position in the Y direction of the center of the circular pattern can be obtained from {(first quadrant output + second quadrant output)-(third quadrant output + fourth quadrant output)}. From this, it is possible to measure the amount of deviation of the rotational axis position based on the circular pattern. When a quadrant optical sensor is used, measurement can be performed at a higher speed than when a CCD is used.

  Also in this case, if the position of the exposure axis of the exposure light 8 for drawing is changed in accordance with the change in the center position of the observed circular pattern, the movement on the sample 7 will not occur unless the linear stage 2 is moved. The drawing locus is a circle centered on the center position of the circular pattern. Therefore, even when the center of the sample 7 is not aligned with the rotation center or the rotation axis is decentered, the position of the exposure axis of the drawing exposure light 8 varies according to the variation of the center position of the observed circular pattern. By doing so, it is possible to perform accurate circular and spiral drawing on the assumption that the sample 7 is rotated around the center position of the circular pattern.

  As described above, in the embodiment of the present invention, it is possible to measure the rotation axis of the rotary stage with nanometer order accuracy using a measurement system having a very simple configuration. Further, an expensive coordinate measurement system such as an interferometer is not necessary. The measurement system used in the present invention is the same as the alignment sensor put into practical use in the exposure apparatus, and is very inexpensive. By performing correction exposure based on the measured rotational axis position information, patterning can be performed with the same degree of accuracy as the measurement accuracy.

  In the above embodiment, the rotation axis measurement system such as the half mirror 13, the magnifying optical system 14, the CCD sensor 15, and the four-part optical sensor 17 includes the interferometer movable mirror 11 for XY coordinate measurement. By installing on the moving body (support base 10), it is possible to measure the position of the rotating shaft with respect to the moving mirror 11. In this case, since the rotation axis measurement system is installed near the movable mirror and the movement mirror, the reference of the XY coordinates and the reference of the rotation axis measurement system can be brought close, and a simple and stable measurement system can be constructed.

  In the above description, it is assumed that the circular pattern is formed on the sample. However, when the sample is in a donut shape (for example, a CD disk), a similar effect can be obtained by forming a circular pattern on the surface of the rotating body and observing it.

  In the above description, an example using a four-divided sensor is shown, but a sensor with a number of divisions other than four (multi-divided sensor) may be used. For example, a two-divided sensor, a three-divided sensor, or a sensor with five or more divisions can be used.

1 is a view showing an outline of an exposure apparatus according to a first embodiment of the present invention. It is a figure which shows the circular pattern formed in the sample, and the image of the CCD sensor. It is a figure which shows the outline | summary of the exposure apparatus which is the 2nd Embodiment of this invention. It is a figure which shows the relationship between a 4-part dividing optical sensor and the image of a circular pattern.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Base, 2 ... Linear stage, 3 ... Motor, 4 ... Feed screw, 5 ... Rotation stage, 6 ... Sample stand, 7 ... Sample, 8 ... Exposure light for drawing, 9 ... Interferometer, 10 ... Support stand, DESCRIPTION OF SYMBOLS 11 ... Moving mirror, 12 ... Laser beam, 13 ... Half mirror, 14 ... Magnifying optical system, 15 ... CCD sensor, 16 ... Illuminating device, 17 ... 4-part dividing optical sensor

Claims (4)

An exposure apparatus for patterning a micropattern on a sample on a rotary table while rotating the rotary table, and imaging an image of a circular pattern formed near the rotation center of the sample or near a rotation axis on a rotating body An exposure apparatus comprising: a measuring unit that measures a shift amount of a rotational axis position from a position of a circular pattern imaged by the imaging unit during rotation of the rotary table. An exposure apparatus for patterning a micropattern on a sample on a rotary table while rotating the rotary table, and an image of a circular pattern formed near the rotation center of the sample or near the rotation axis on the rotating body, An optical system that forms an enlarged image on a multi-divided sensor, and a measuring device that measures the amount of deviation of the rotational axis position from the output of the multi-divided sensor obtained during rotation of the rotary table. Exposure device. 3. The exposure apparatus according to claim 1, wherein the imaging unit or the multi-divided sensor and the optical system are mounted on a linear stage on which the rotary table is mounted. An exposure apparatus. 4. The exposure apparatus according to claim 1, wherein the exposure apparatus has a function of correcting a patterning position of the minute pattern based on a deviation amount of a rotation axis position measured by the measurement apparatus. 5. An exposure apparatus comprising:

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