JPH11185304A - Laser exposure device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent resonance of an exposure optical system due to cooling water vibration and to improve precision of an optical axial positioning, exposure positioning mechanism by fitting a water cooling laser light source and an exposure optical system to respectively different surface plates. SOLUTION: A first surface plate 1a and a second surface plate 1b are laminated through a support member 26, and vibration-absorbing mechanisms 24, 25 are provided between the first surface plate 1a and the support member 26 and between the second surface plate 1b and the support member 26, and the vibration on the first surface plate 1a and the vibration etc., from a floor on which this device is arranged are prevented from propagating to the second surface plate 1b on which the exposure optical system is provided. Further, a temp. controlling cooling water circulation pipe is connected to the first surface plate 1a, and a laser light source 2 oscillating laser light in an ultraviolet region is provided on the first surface plate 1a, and the emitted laser light is led to the second surface plate 1b through an optical fiber 15. This laser light is made incident on a noise reducer 4 through a collimate lens 22, and further, is made incident on an optical modulator 6 to be led to a rotating optical disk master disk 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser exposure apparatus for exposing an optical disk master.

[0002]

2. Description of the Related Art In the field of photolithography using a laser, a water-cooled laser is often used. this is,
In order to obtain a laser output required for photolithography, a large amount of power must be supplied, and as a result, a large amount of heat is generated.

In a conventional laser exposure apparatus, a laser light source is installed on the same platen as an exposure optical system. This is because the entire optical system including the laser light source and the exposure optical system is fixed on the same surface plate, the optical path length is made as short as possible, and the optical axis is stabilized.

FIG. 3 shows a schematic configuration of a conventional laser exposure apparatus for recording a master optical disc.

As shown in the figure, conventionally, a laser light source 2, an exposure optical system for guiding light from the laser light source 2 onto a glass master 13 for an optical disk, and a rotation support mechanism such as a spindle 14 for rotatingly supporting the glass master 13 are shown. Are all fixed on the same surface plate 1.

The exposure optical system is based on, for example, a noise reducer 4 for reducing noise of the laser light 3 from the laser light source 2, a mirror 5 for deflecting the optical axis of the laser light 3, and a recording signal from a signal source 7. An optical modulator 6 for modulating the laser light 3 and a recording light 8 obtained by the modulation are transmitted to a mirror 9,
It comprises an objective lens 12 and the like for condensing light on a glass master 13 via a lens 10 and a mirror 11.

[0007]

In recent years, in the field of photolithography, the exposure design has been further miniaturized, and there has been a demand for higher precision of the exposure apparatus.

For example, in an optical disk master recording apparatus, a CD (compact disk) has a track pitch of 1.6 μm, while a DVD (Digital Video)
Disc) has a track pitch as narrow as 0.74 μm. Further, there is a great possibility that an optical disk having a track pitch of 0.5 μm or less will appear in the future.

[0009] However, when the recording pitch becomes finer in this way, especially in the case of a water-cooled laser, the vibration caused by the circulation of the cooling water or the like cannot be ignored. That is, in the conventional apparatus as shown in FIG. 3, the vibration of the laser light source 2 due to the cooling water flow propagates to the exposure optical system via the surface plate 1, and the exposure optical system causes mechanical resonance. . In this case, a decrease in the positional accuracy of the exposure optical axis due to this cannot be ignored.

In order to avoid this vibration, for example,
It is conceivable that the laser light source 2 is separated from the surface plate 1 and fixed. However, simply fixing the laser light source 2 separately from the surface plate 1 causes vibration due to the positional relationship between the laser light source 2 and the exposure optical system. As a result, there is a problem that an optical axis shift occurs between them.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described circumstances, and has as its object to prevent a vibration in a water-cooled laser light source from propagating to an exposure optical system and to suppress optical axis deviation to achieve high precision. An object of the present invention is to provide a laser exposure apparatus capable of performing an exposure process.

[0012]

That is, the present invention provides a water-cooled laser light source mounted on a first platen,
A laser exposure apparatus (hereinafter, referred to as the present invention) comprising: an exposure optical system attached to a second surface plate different from the surface plate; and an optical fiber for optically connecting the laser light source and the exposure optical system. ).

According to the laser exposure apparatus of the present invention, since the water-cooled laser light source and the exposure optical system are mounted on different surface plates, the vibration of the water-cooled laser light source caused by the cooling water flow is reduced. It is possible to perform high-precision exposure processing without propagating to the optical system, and because the laser light source and the exposure optical system are connected by the optical fiber, displacement occurs between the two surface plate positions. Even if it occurs, the deviation of the optical axis due to this can be suppressed, and the exposure processing can be stabilized and the accuracy can be improved.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the laser exposure apparatus of the present invention, it is preferable that at least the second platen has a vibration removing mechanism. Further, it is preferable that the first platen also includes a vibration isolation mechanism. In particular, when both the first surface plate and the second surface plate are provided with a vibration isolation mechanism, the vibration can be further removed.

The first surface plate and the second surface plate are not particularly limited as long as they are different from each other. For example, they may be arranged in a stacked shape. (See FIG. 2).

Further, the laser exposure apparatus of the present invention can be used for exposing a master of an optical disk. The laser light source at this time is desirably an ultraviolet laser light source having an oscillation wavelength of 200 to 380 nm.

Next, referring to FIG. 1, an optical disk master recording apparatus (master exposure apparatus) based on the laser exposure apparatus of the present invention.
Will be described.

As shown in FIG. 1, in this optical disk master recording apparatus, a laser light source 2 is disposed on a first base 1a, and a second base different from the first base 1a. The disc 1b is provided with an exposure optical system for guiding a laser beam from the laser light source 2 onto the glass master 13 for an optical disc, a spindle 14 for rotatably supporting the glass disc 13 and a rotation support mechanism such as a turntable 18 and the like. I have. And
The first surface plate 1a and the second surface plate 1b
The laser light from the laser light source 2 is propagated through the optical fiber 15. In addition,
Needless to say, it is desirable that the optical fiber 15 be made of a material suitable for the intensity and wavelength of the laser light 3.

The exposure optical system comprises an optical fiber 1
Noise reducer 4 for reducing the noise of laser light 3 from 5, mirror 5 for deflecting the optical axis of laser light 3, signal source 7
An optical modulator 6 for modulating the laser beam 3 based on a recording signal from the optical disc 6 and a recording beam 8 obtained by the modulation are condensed on a glass master 13 via a mirror 9, a lens 10 and a mirror 11. It comprises an objective lens 12 and the like.

As shown in the figure, the light source laser 2 is installed on a first platen 1a different from the exposure optical system. At this time, in order to avoid the influence of floor vibration and the like, a laser light source is newly added. It is desirable that a surface plate (first surface plate) provided with a vibration isolation mechanism be prepared and installed on this surface plate.

Further, it is preferable that the exposure optical system is deployed on a second surface plate 1b provided with a vibration removing mechanism, so that unnecessary vibration is removed.

Next, the behavior of laser light in the optical disk master exposure apparatus shown in FIG. 1 will be described.

First, ultraviolet laser light having an oscillation wavelength of 200 to 380 nm emitted from the laser light source 2 (laser head) is guided to the exposure optical system via the optical fiber 15. Collimator lenses 21 and 22 may be provided before and after the optical fiber 15 for the purpose of condensing laser light and aligning the light flux in parallel. In addition, the optical fiber 15
When a polarization-maintaining laser is used, the laser light emitted from the optical fiber 15 is the same as the laser light emitted from the laser light source 2 in both the intensity distribution and the deflection direction.

Laser light 3 emitted from optical fiber 15
Is, for example, an electro-optic element (EOM).
lator), an analyzer, and a photodetector, and the noise is reduced (noise cut). Thereafter, the laser light 3 is applied to an optical modulator 6 connected to a signal source 7, for example, an electro-optic element (EOM) or an acousto-optic element (AOM).
) Performs a predetermined modulation.

Then, the modulated recording light 8 passes through the mirror 9, the condenser lens 10, and the mirror 11 to the objective lens 1.
2 and a master disc 13 by an objective lens 12.
The photoresist film focused on the upper surface and disposed on the master disk 13 is subjected to a predetermined fine pattern processing.

Thereafter, although not shown, the photoresist film is removed, and a glass master of the optical disk is manufactured.
Based on this, an optical disk is manufactured through predetermined processing steps such as a metal master manufacturing step.

At this time, a photoresist having a desired thickness is formed on the master disk 13 by, for example, spin coating.
For example, it is applied to a thickness of 1 / (4n) of the reading light wavelength. Here, n is a refractive index of a resin for finally transferring pits, which is about 1.5. The disk master 13 is rotated by the spindle 14 and the turntable 18 at a constant angular velocity or a constant linear velocity,
The objective lens 12 moves on the master disk 13 in the direction of the arrow in the drawing so as to have a desired track pitch in accordance with the rotation speed.

As described above, in the laser exposure apparatus of the present invention, the laser light source is not on the same plate as the exposure optical system. Therefore, the vibration caused by the cooling water flowing in the laser light source (laser head) does not cause mechanical resonance of the exposure optical system, and the accuracy of the optical axis position and the exposure positioning mechanism can be improved. In addition, if the input / output end face of the optical fiber and the collimator lens are firmly fixed, the play of the fiber body due to the degree of freedom can be used to insulate the laser optical axis from being displaced by the displacement between the two surface plates. it can.

As described above, in particular, when the laser exposure apparatus of the present invention is applied to an optical disk master exposure apparatus, an effect of stabilizing exposure, particularly, a reduction in track pitch unevenness can be expected.

In recent years, a near-ultraviolet laser having a wavelength around 350 nm has been used as a recording light source for an optical disk.
In the future, the wavelength will be shorter, 200 nm to 300 n.
It is expected that a far ultraviolet laser of about m will be used. In the future, in the exposure and production of an optical disc master using these light sources, the track pitch is expected to be extremely narrow to 0.5 μm or less, and it is desired to further reduce the track pitch unevenness as compared with the present. . However, at present, a water-cooled gas laser is a general light source among these laser light sources having an ultraviolet oscillation wavelength. Therefore, the usefulness of the laser exposure apparatus of the present invention is further increased in the sense of reducing track pitch unevenness in a high-density optical disk recording apparatus having a light source wavelength in an ultraviolet region.

When the laser exposure apparatus of the present invention is applied, it is not necessary to install a laser on the same platen as the exposure optical system. For example, it is possible to use a three-dimensional space, for example, by installing a surface plate on which a laser light source is mounted on the bottom or ceiling of an exposure apparatus pedestal.

Next, the laser exposure apparatus of the present invention will be described.
A preferred embodiment will be described with reference to FIG.

In this embodiment, the second plate is placed on the first platen 1a.
An optical disk master exposure apparatus having a structure in which a surface plate 1b is laminated (a structure in which a laser light source is installed at the bottom of a base of the exposure apparatus).

As shown in FIG. 2, the first platen 1a and the second platen
The platen 1b is laminated via a support member 26. An anti-vibration mechanism 24 (corresponding to 16 in FIG. 1) is provided between the first surface plate 1a and the support member 26, and the vibration in the first surface plate 1a is transmitted through the support member 26. So that it does not propagate to the second platen 1b.
Also, a vibration isolation mechanism 25 (corresponding to 17 in FIG. 1) is provided between the second surface plate 1b and the support member 26, and the vibration on the first surface plate 1a and this device are arranged. It is configured such that vibrations from the floor and the like do not propagate to the second surface plate 1b provided with the exposure optical system.

A cooling water circulation pipe for temperature control, not shown, is connected to the first master 1a, and a laser light source 2 capable of oscillating ultraviolet laser light is provided. The laser light emitted from the laser light source 2 is guided to the second base 1b via the optical fiber 15.

On the second master 1b, an exposure optical system including a collimator lens 22, a noise reducer 4, a light modulator 6, a lens 10, a mirror 11, and an objective lens 12 is provided, and further, not shown. The optical disk master 13 is fixed on the turntable 18 on the spindle by vacuum suction or the like.

Then, as described above, the second surface plate 1b
Is incident on the noise reducer 4 via the collimator lens 22, is subjected to noise cut by the noise reducer 4, and further to the optical modulator 6 connected to a signal source (not shown). Incident. Here, the signal light 8 on which a predetermined recording signal is placed is guided to the rotating optical disc master 13 via the lens 10, the mirror 11 and the objective lens 12.

The lens 10, the mirror 11 and the objective lens 12 are mounted on a moving surface plate 23, and can be moved in the direction of the arrow in the figure so as to form a desired track pitch with respect to the optical disk master 13. is there.

As described above, in the optical disk master exposure apparatus having the configuration shown in FIG. 2, resonance in the exposure optical system due to vibration of the cooling water or the like can be prevented, and the exposure processing can be performed with good accuracy. Since it has a structure in which the first surface plate and the second surface plate are stacked, the size, weight, and cost of the device can be reduced.

Although the present invention has been described with reference to the preferred embodiments, the present invention is not limited to the above-described embodiments.

For example, the laser light source may be provided at the bottom of the gantry of the exposure apparatus as described above. Alternatively, for example, the laser light source may be provided on the ceiling and other devices may be provided on the floor. The second surface plate and the second surface plate may be installed at arbitrary positions.

The laser exposure apparatus of the present invention is not limited to an optical disk master exposure apparatus.
The present invention can also be applied to a mask pattern forming device for an exposure mask (reticle) used in a manufacturing process of a semiconductor device.

[0043]

According to the laser exposure apparatus of the present invention,
A water-cooled laser light source mounted on a first surface plate, an exposure optical system mounted on a second surface plate different from the first surface plate, and a space between the laser light source and the exposure optical system. Optically connected optical fiber, and the water-cooled laser light source and the exposure optical system are mounted on different surface plates, respectively, so that the resonance of the exposure optical system caused by the vibration of the cooling water is reduced. Therefore, the accuracy of the optical axis position and the exposure positioning mechanism can be improved. In addition, by connecting the laser light source and the exposure optical system on different surface plates using an optical fiber, even if displacement occurs between the two surface positions, it is possible to insulate the optical axis from being displaced.

In particular, by providing the present invention to an optical disk master exposure apparatus, it is possible to reduce minute track pitch unevenness due to the vibration of a laser light source, and to install a laser at the bottom or ceiling of a gantry of an exposure apparatus. For example, three-dimensional use is possible, and the degree of freedom of arrangement is increased, and the size, weight, and cost of the exposure apparatus can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an optical disk master exposure apparatus based on a laser exposure apparatus of the present invention.

FIG. 2 is a schematic configuration diagram of an optical disc master disc exposure apparatus according to an embodiment of the present invention.

FIG. 3 is a schematic configuration diagram of a conventional optical disc master exposure apparatus.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Surface plate, 1a ... 1st surface plate, 1b ... 2nd surface plate, 2 ...
Laser light source (laser head), 3 laser light, 4 noise reducer, 5, 9, 11 mirror, 6 optical modulator, 7
Signal source, 8: recording light, 10: lens (condensing lens), 1
2: Objective lens, 13: Glass master, 14: Spindle, 15: Optical fiber, 16, 17: Vibration isolation mechanism, 18
... turntable, 21, 22 ... collimator lens, 2
3: Moving table, 24, 25: Anti-vibration mechanism, 26: Support member

Claims (6)

[Claims] 1. A water-cooled laser light source mounted on a first surface plate, an exposure optical system mounted on a second surface plate different from the first surface plate, the laser light source and the exposure A laser exposure apparatus, comprising: an optical fiber that optically connects between optical systems. 2. The laser exposure apparatus according to claim 1, wherein at least the second platen has a vibration isolation mechanism. 3. The laser exposure apparatus according to claim 2, wherein said first platen also includes a vibration isolation mechanism. 4. The laser exposure apparatus according to claim 3, wherein the first surface plate and the second surface plate are arranged so as to be stacked on each other. 5. The laser exposure apparatus according to claim 1, wherein the laser exposure apparatus is used for exposing an optical disc master. 6. The laser light source according to claim 1, wherein said laser light source has an oscillation wavelength of 200-3.
The laser exposure apparatus according to claim 5, wherein the laser exposure apparatus is an ultraviolet laser light source of 80 nm.