JP2001159742A - Divided exposure device using hologram scanning system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a divided exposure device which is made compact by suppressing the number of components increased according to the number of scanning systems by making the components commonly usable when the exposure device has plural scanning systems, executes drawing with high resolution by increasing a beam diameter and is capable of correcting the misalignment of scanning lines in a sub-scanning direction. SOLUTION: This divided exposure device comprises a light source which emits one laser beam, a transmission type diffraction element which splits the one laser beam emitted from the laser beam source to plural beams, an optical modulation element which modulates the plural laser beams respectively in accordance with drawing data, a beam expander which expands the respective beam diameters of the plural laser beams and respective hologram scanning systems on which the expanded laser beams are made incident. Further, the device has an optical deflector and a beam detector on an exposure table and executes the correction in the sub-scanning direction of the scanning lines by controlling the optical scanner in accordance with the misalignment quantity of the scanning lines detected by the beam detector.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hologram scanning system unit for scanning a drawing object with a laser beam in the main scanning direction. And an exposure apparatus for performing exposure.

[0002]

2. Description of the Related Art Conventionally, as a method of forming a circuit pattern on a substrate, for example, a photopolymer or the like is uniformly deposited on a substrate on which a thin film made of a conductive metal material such as copper is uniformly deposited. 2. Description of the Related Art There is known a method in which a circuit pattern formed on an exposure printing mask is covered with an exposure printing mask (photomask film) having a circuit pattern formed thereon, and the circuit pattern formed on the exposure printing mask is exposed to ultraviolet light or the like.

In recent years, as an alternative to the above method, a laser beam modulated according to raster data corresponding to a circuit pattern is scanned on a substrate via a deflecting means such as a polygon mirror without using an exposure printing mask. A method of exposing an image corresponding to a circuit pattern directly to a substrate has been proposed. A typical example is drawing of a circuit pattern or a transparent electrode pattern of a plasma display panel (PDP) in a process of manufacturing a printed circuit board using a photolithographic technique. In this case, the object to be drawn includes, for example, a photosensitive film for a photomask or a photoresist layer on a substrate.

On the other hand, when a wide range of exposure is performed using a laser drawing apparatus that deflects a laser beam with the above-described polygon mirror, the fθ lens becomes extremely large and heavy, making it extremely difficult to manufacture the fθ lens. There was a problem that could not be secured. In addition, it is necessary to increase the rigidity of the holding frame of the fθ lens and the base on which these optical components are installed so that the deflection due to the weight of the fθ lens and the condenser lens does not affect the optical performance. Therefore, the mass of these laser writing apparatuses is 1000 to 2000.
It has a problem that it is extremely poor in portability and expensive. In order to solve these problems, there has been proposed a division exposure apparatus which divides a scanning range on an object to be drawn and performs exposure.

By the way, as described above, a polygon mirror,
In a divided exposure apparatus provided with a plurality of scanning systems each including an fθ lens and a condenser lens, portions that are not used for scanning both ends of the condenser lens overlap at connection portions of the divided scanning systems. Cannot be arranged side by side in the scanning line direction. Therefore, for example, a configuration is adopted in which the condenser lenses are arranged so as to be shifted from each other by the width of the condenser lens in the sub-scanning direction.
When moving to the scanning system, it is necessary to move the exposure table,
The positioning error of the exposure table poses a problem.

In a division exposure apparatus using a polygon mirror for the scanning system, a plurality of components such as polygon mirrors are required in accordance with the number of scanning systems, and each polygon mirror is made thin in order to suppress an increase in the size of the apparatus. A smaller one is used, and accordingly, it is necessary to reduce the beam diameter of the light source.
When the beam diameter of the light source is reduced in this manner, the diameter of the condensed spot on the exposure surface becomes large, so that there is a problem that high-resolution drawing cannot be performed.

[0007]

SUMMARY OF THE INVENTION The present invention relates to an exposure apparatus having a plurality of scanning systems, by suppressing the number of components that increase in accordance with the number of scanning systems by using common components. It is another object of the present invention to provide a divided exposure apparatus capable of performing high-resolution drawing by making the apparatus compact, increasing the beam diameter, and correcting the positional deviation of the scanning line in the sub-scanning direction.

[0008]

A split exposure apparatus according to the present invention comprises a light source for emitting one laser beam, and a transmission type diffraction element for splitting one laser beam emitted from the laser light source into a plurality of beams. A light modulation element that modulates a plurality of laser beams based on drawing data, a beam expander that expands the beam diameter of the plurality of laser beams, and a hologram scanning system that receives the expanded laser beam. Composed of

Further, a beam detector is slidably attached to an end of the exposure table on which the object to be drawn is mounted via a guide rail, and the exposure table is moved to make a scanning line incident on the beam detector. Thus, the beam detector can be configured to detect the amount of positional deviation of the scanning line in the sub-scanning direction.

Further, by providing an optical deflector provided with a reflecting plate, the optical deflector is controlled based on the positional deviation of the scanning line detected by the beam detector, and the angle of reflection of the beam on the optical deflector is adjusted. By changing the position, the positional deviation of the scanning line in the sub-scanning direction can be corrected.

[0011]

1 to 3 show a main part of a division exposure apparatus using two hologram scanning systems according to one embodiment of the present invention. The object to be drawn 14 placed on the exposure table 13 is divided and exposed by two scanning systems. In FIG. 1, one laser beam emitted from a light source 1 is split into two beams of equal intensity by a transmission type diffraction element 2 and further collimated by a collimator lens 3.
Is converted into parallel light, enters the incident optical system, and is then guided to the scanning system. In this way, by using a configuration in which one laser beam from one light source is divided and used, it is not necessary to have a light source for each scanning system, and compared with a case where a light source is mounted for each scanning unit, There is no need to adjust the emission intensity between each light source.

The two split and collimated beams are:
Each of them enters an incident optical system including an optical modulator 5, an optical polarizer 6, and a beam expander 9. In the incident optical system,
As described later in detail, beam modulation and the like are performed based on the raster data. The beam that has passed through the incident optical system enters one facet of the hologram disk 10.
The hologram disc 10 is driven to rotate by a motor 11, and the facet on which the beam is incident is moved with the rotation, so that the beam LB1 is guided to the concave mirror 12 while being deflected in the direction of arrow S in FIG.

FIG. 2 shows the incident optical system of the division exposure apparatus of the present invention in detail. The incident optical system includes an optical modulator 5, an optical deflector 6, an aperture plate 8, and a beam expander 9. 2 collimated by collimator lens 3
One of the beams is guided to an optical modulator 5 in the incident optical system via a beam bender 4 (FIG. 1). Optical modulator 5
Is constituted by an acousto-optical element, and when a voltage that changes based on raster data is applied to the optical modulator 5, the diffraction direction of a beam passing through the optical modulator 5 changes with the change in the voltage. Here, if the light modulator 5 is arranged so that the beam is shifted from the central opening of the diaphragm plate 8 when the voltage is turned on or off, the beam is blocked there. ON
OFF control is performed. In addition, by arranging the aperture plate 8 so as to pass only the first-order light from the optical modulator 5, it is possible to completely block the zero-order light, which is noise.

The beam that has passed through the optical modulator 5 is reflected by a reflection plate 7 attached to an optical deflector 6, and reaches a beam expander 9 through an opening at the center of a diaphragm plate 8. The beam expander 9 expands the beam diameter of the beam generated by the light source 1. Here, in the case of a divided exposure apparatus using a polygon mirror in a conventional scanning system, a light source having a beam diameter of 2 to 3 mm is usually used. When a laser beam is focused, the focused spot diameter d is generally represented by d = 2.44 · λ · f / D, where (λ is the wavelength, f is the focal length, D
Represents the beam diameter of the light source. ) For example, the beam diameter D of the light source
When a laser beam of = 2 mm is focused at a focal length f = 200 mm, and the wavelength of the laser is 650 nm, the focused spot diameter d is about 0.16 mm. On the other hand, in the present invention, since the hologram disk is used for the scanning system, the beam diameter of the light source can be increased.
Therefore, as in the present embodiment, the beam from the light source 1 can be configured to be incident on the hologram disk 10 after the beam diameter is expanded by the beam expander 9. The beam expander 9 can generally increase the beam diameter by a factor of 5 to 10 times. For example, assuming that the magnification of the beam expander 9 is 10 times, the beam diameter D of the light source becomes 10 times.
016 mm. According to the present invention, it is possible to perform high-resolution drawing even though the divided exposure apparatus has a plurality of scanning systems, since the smaller the focused spot diameter is, the higher the drawing performance can be. It is.

The beam incident on the hologram disc 10 from the beam expander 9 is
Are scanned by rotating, and are condensed by the concave mirror 12 and reach the exposure table 13. The focused beam is scanned on the exposure table in the direction perpendicular to the screen of FIG. By making the reflecting surface of the concave mirror 12 a toric surface, it is possible not only to condense the beam but also to have an fθ function.

FIG. 3 shows a scanning range of the beam condensed by the concave mirror 12, and as shown in FIG.
It is preferable that the respective scanning systems are arranged so that the joint between the two scanning ranges on 3 overlaps each other. An object to be drawn 14 such as a film or a printed circuit board is placed on the exposure table 13 where the beam is scanned, and the exposure table 13 is moved in the direction of arrow A (sub-scanning direction) in FIG. Drawing is performed over the entire body.

As shown in FIGS. 1 and 2, a beam detector 20 is provided at the end of the exposure table 13 via a guide rail 21 so as to be slidable in the beam scanning direction. The beam detector 20 is provided for the purpose of detecting the positions of two scanning lines, and is configured by, for example, a semiconductor position detector (PSD) or a quadrant. When the detection by the beam detector 20 is performed,
The exposure table 13 is moved until the center of the detection surface of the beam detector 20 is positioned on the scanning line, the beam is turned on, and the beam detector 20 is moved along the scanning line on the guide rail while detecting the beam. By this operation, it is possible to detect the linearity of the scanning line, the deviation in the sub-scanning direction, or the positional deviation at the joint of the scanning lines for each scanning system.

Next, a description will be given of a case of correcting a shift of a scanning line in the sub-scanning direction. The incident optical system has an optical deflector 6. The optical deflector 6 is formed of, for example, a piezo element, and is configured to swing in the direction of arrow B in FIG. 2 depending on the voltage applied to the projection on which the reflecting mirror 7 is attached. When the projection of the optical deflector 6 swings in the direction of arrow B, the angle of reflection of the beam reflected by the reflector 7 changes, and accordingly, the position of the beam spot on the exposure table 13 also changes in the sub-scanning direction. That is, by controlling the voltage of the optical deflector 6 based on the shift information of the scanning line obtained from the beam detector 20, the scanning line can be moved by a desired amount in the sub-scanning direction and the correction can be performed.

Positional deviations in the state where the scanning lines are moved in parallel in the sub-scanning direction, or linearity distortions such as the curvature and inclination of the scanning lines cause variations in assembly of each scanning system or variations in manufacturing of each facet of the hologram disk. Caused by For example, if the scanning line shifts in parallel in the sub-scanning direction without being equal in pitch in each sub-scanning direction due to manufacturing variations of each facet of the hologram disc, one correction amount is required for each scan. Optical deflector 6
To control the angle of reflection at. For the linearity distortion of the scanning line, the reflection angle at the optical deflector 6 is controlled so that the position in the sub-scanning direction is corrected in synchronization with the main scanning during one scanning.

The detection of the positional deviation of the scanning line using the beam detector 20 is performed at the time of assembling the divided exposure apparatus.
Alternatively, it is performed each time drawing on one photosensitive material is completed.
In particular, by performing the drawing every time the drawing on one photosensitive material is completed, it is possible to cope with a temporal change of a component such as a facet.

In the above embodiment, the case where the beam from the light source is split into two by the transmission type diffraction element has been described. A divided exposure apparatus using the above scanning system can be configured. In this case, since the intensities of the plurality of beams split by the transmission type diffraction element are equal,
There is no need to adjust the beam intensity for each scanning system.

[0022]

As described above, according to the present invention, even when a plurality of scanning systems are provided, one beam from the light source is split into a desired number of parallel light beams having the same intensity, and Since the light can be guided to the scanning system, it is not necessary to provide a light source for each scanning system, and the trouble of adjusting the emission intensity between the light sources is not required. In addition, since the hologram is used for the scanning system, the apparatus can be made compact and the beam diameter can be increased. Further, by detecting a beam scanned on the exposure table, the positional deviation of the scanning line between the scanning systems due to the assembly variation of the scanning system, or the sub-scanning direction of the scanning line due to the manufacturing variation of each facet of the hologram disk. Misalignment can be corrected. Accordingly, since each scanning system has a high resolution and there is no positional deviation between the scanning systems, it is possible to perform high-definition drawing.

[Brief description of the drawings]

FIG. 1 is a plan view illustrating a main part of a division exposure apparatus of the present invention.

FIG. 2 is a side view of the division exposure apparatus of FIG.

FIG. 3 is a front view of the division exposure apparatus of FIG.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 laser generator 2 transmission diffraction element 3 collimator lens 4 beam bender 5 optical modulator 6 optical deflector 7 reflecting mirror 8 aperture plate 9 beam expander 10 hologram disk 11 motor 12 concave mirror 13 exposure table 14 object to be drawn 20 beam detector 21 Guide rail 22 Moving table

Claims (3)

[Claims] 1. A light source for emitting one laser beam, a transmission diffraction element for dividing one laser beam emitted from the laser light source into a plurality of beams, and a plurality of laser beams based on drawing data, respectively. A hologram, comprising: a light modulation element that modulates; a beam expander that expands the beam diameter of each of the plurality of laser beams; and a hologram scanning system that receives the expanded laser beams. A division exposure apparatus using a scanning system. 2. A beam detector slidably attached via a guide rail to an end portion of an exposure table on which an object to be drawn is placed, wherein the exposure table is moved to move the exposure table onto the beam detector. The division exposure apparatus using the hologram scanning system according to claim 1, wherein a position of a beam of the scanning line is detected by making the scanning line incident. 3. An optical deflector for changing an exposure position of the beam in the sub-scanning direction, wherein the optical deflector is controlled based on positional information of the scanning line detected by the beam detector, and 3. The division exposure apparatus using the hologram scanning system according to claim 2, wherein the correction in the sub-scanning direction is performed.