JPH10228661A - Master disk manufacturing aligner for optical recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance exposing accuracy of the master disk of an optical recording medium. SOLUTION: A liquid tight and fixed transparent shield plate 21 is provided between an objective lens 14 for exposure light and a photoresist layer 16, and 1st and 2nd transparent liquids 31 and 32 having light transmissibility of the exposure light are filled into between the objective lens 14 and the fixed transparent shield plate 21 and then the fixed transparent shield plate 21 and a substrate coated with the photoresist layer 16 respectively. Consequently, the 2nd transparent liquid is prohibited from flowing to the objective lens 14, while the 1st transparent liquid in contact with the objective lens does not flow (move) in spite of rotating of the substrate, so that an axial drift, etc., of the objective lens 14 does not take place.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exposure apparatus for producing a master of an optical recording medium.

[0002]

2. Description of the Related Art In a conventional optical recording medium such as a compact disk (CD) or a laser disk (LD) for recording various kinds of information for audio, video and other purposes, data information and tracking servo information are recorded on an information recording layer. Fine irregularities such as phase pits and pre-grooves where signals and the like are recorded are formed.

[0003] The fine irregularities constituting the information recording layer can be formed simultaneously with the injection molding of the substrate of the optical recording medium, or can be formed by a photopolymerization method, a so-called 2P method or the like.

In the injection molding or the 2P method, a stamper having fine irregularities for transferring and forming fine irregularities to be finally formed is used. In manufacturing the stamper, first, a master is manufactured. The master is formed by applying a photoresist on a substrate constituting the master, for example, a polished smooth glass plate, pattern-exposing the photoresist to form fine irregularities, and applying, for example, Ag plating to the surface thereof. The stamper is formed by applying metal plating to the master produced in this way and peeling it off, or by repeating this process.

As schematically shown in FIG. 4, a master exposure apparatus 50 for performing pattern exposure on a photoresist at the time of manufacturing the master includes an exposure laser beam L for generating an exposure laser beam L having a wavelength sensitive to the photoresist. A light source 51 and a modulator 52 for modulating the exposure laser beam L in accordance with an exposure pattern such as recording information are provided, whereby the intensity-modulated exposure laser beam L is reflected by a mirror 53, for example. The laser beam L for exposure is focused on the surface of a photoresist 56 on a substrate 55 on which a master is to be formed through the objective lens 54 so that a fine recording pattern is recorded. In the conventional master exposure apparatus, a simple space, that is, air is interposed between the objective lens 54 and the photoresist 56 on the substrate 55 as shown in FIG.

On the other hand, in recent years, the recording density of optical recording media has been increased, and finer position control,
That is, miniaturization of the spot of the exposure laser beam L is required.

As described above, in order to miniaturize the spot of the exposure laser beam L, that is, to improve the focusing power,
As shown in FIG. 6, a so-called oil immersion method has been proposed in which exposure is performed in a state where a space between the objective lens 54 and the photoresist 56 is filled with a medium having a high refractive index, for example, a liquid.

In FIG. 6, the angle between the exposure laser beam L and the vertical line of the photoresist surface 56 is θ, and the numerical aperture of the objective lens 54 is N.D. A. Assuming that the refractive index of the medium between the objective lens 54 and the photoresist 56 is n, the diameter φ of the exposure laser beam L focused on the surface of the photoresist 56 is
Is represented by the following (Equation 1), where λ is the wavelength of

[0009]

## EQU1 ## φ = (0.82 × λ) / N. A. (However, NA = n × sin θ)

That is, if a medium whose refractive index n is larger than the refractive index of air (n ₀ = 1) is applied as a medium between the objective lens 54 and the photoresist 56, the aperture of the objective lens 54 can be increased. Number N. A. Becomes large, and as a result, the value of φ (diameter of the beam L) can be reduced,
It is possible to improve the focusing power of the exposure laser beam L.

[0011]

On the other hand, as described above, when the photoresist is exposed by the exposure laser beam L, the objective lens 54 and the substrate 55 are
It is necessary to move relatively. For example, when the disk-shaped substrate 55 is used, while rotating the substrate 55,
The exposure laser beam L is moved in the radial direction of the substrate 55 to scan the laser beam spot in a spiral on the photoresist surface.

However, when the photoresist is exposed using the above-described liquid immersion method, the objective lens 5
When the substrate 4 and the substrate 55 are relatively moved, the liquid having a high refractive index between the objective lens 54 and the photoresist 56 is dragged and moved by the movement of the substrate 55, for example, rotation.
At this time, since the objective lens 54 exists so as to oppose the movement of the liquid having the high refractive index, the movement of the liquid may cause the objective lens 54 to move in the axial direction or to disturb the autofocus operation. An effect will occur.

When the photoresist is exposed in a state where the axis of the objective lens 54 is deviated as described above, the optical recording medium finally obtained has poor quality such as uneven track pitch and uneven modulation of a reproduced signal. It has signal characteristics.

Therefore, in the present invention, when the photoresist is exposed by using the liquid immersion method, the condensing power of the exposure laser beam L is improved, the axis of the objective lens 54 is deviated, and the autofocus is performed. Provided is an exposure apparatus for producing a master of an optical recording medium in which operation disturbance is avoided.

[0015]

According to the present invention, there is provided an exposure apparatus for producing a master of an optical recording medium, comprising: a support portion for a substrate coated with a photoresist layer; an objective lens for exposure light; an objective lens; A liquid-tight fixed transparent shielding plate disposed between the substrate and the substrate, on which at least one of the objective lens or the supporting portion of the substrate is passed through the objective lens to arrive at the photoresist layer. The exposure spot to be provided is provided with relative transfer means for transferring and scanning in the photoresist layer, between the objective lens and the fixed transparent shielding plate, and between the fixed transparent shielding plate and the substrate coated with the photoresist layer. The first and second transparent liquids each having light transmittance to the exposure light are filled.

According to the configuration of the present invention described above, the fixed transparent shield plate is provided between the second transparent liquid that flows in accordance with the rotation of the substrate coated with the photoresist layer during the exposure and the objective lens. , The flow of the second transparent liquid can be prevented from being transmitted to the objective lens, and the first transparent liquid with which the objective lens is in contact can rotate despite the rotation of the substrate.
Since no flow (movement) occurs, the objective lens 54
The liquid immersion method, that is, an exposure apparatus for producing a master of an optical recording medium, in which the focusing power of the exposure laser beam L is improved can be realized without causing axial deviation or the like.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific embodiments of the present invention will be described. In the following, a description will be given of a case where the method is applied to pattern exposure of a photoresist surface on a glass substrate produced by transferring a stamper used by an injection molding method or a 2P method when producing a disk-shaped, so-called disk-shaped optical disk. However, the exposure apparatus for producing a master in the present invention is not limited to this shape,
The present invention can be applied to a case where a master used for manufacturing various optical recording media having minute irregularities in an information recording layer, such as a magneto-optical disc, a phase change disc, and a card-shaped or sheet-shaped, is exposed.

An embodiment of the present invention will be described. FIG. 1 is a schematic configuration diagram of an exposure apparatus for producing a master of the present invention, and FIG. 2 is a schematic sectional view of an exposure mechanism in the exposure apparatus for producing a master of the invention.

As shown in FIG. 1, in an exposure apparatus 10 for producing a master according to the present invention, an exposure laser beam generating source 11 for generating an exposure laser beam L, and an exposure laser beam according to an exposure pattern such as recording information. A modulator 12 for modulating L is provided so that, for example, an exposure laser beam L whose intensity has been modulated is reflected by a mirror 13, and exposure is performed in an exposure mechanism 100 surrounded by a broken line in FIG. You.

The exposure mechanism 100 includes an objective lens 14 for condensing an exposure laser beam L, a photoresist 1
6, a support portion 20 for supporting the substrate 15, and a liquid-tight fixed transparent shielding plate 21 disposed between the objective lens 14 and the substrate 15, The first transparent liquid 31 is filled between the light-collecting side surface and the fixed transparent shielding plate 21, and the fixed transparent shielding plate 2
Between the substrate 1 and the substrate 15 to which the photoresist layer 16 has been applied, the second transparent liquid 32 is filled.

FIG. 2 is a schematic structural view of the exposure mechanism 100 in the exposure apparatus 10 for producing a master according to the present invention.

That is, in the exposure mechanism 100 shown in FIG. 2, a substrate 15 having a photoresist surface 16 coated with a photoresist, for example, a substrate made of quartz glass is supported by the support 20. This support 20
For example, it is formed of a disk having a concave portion for receiving and arranging the substrate 15 on its upper surface, is supported so as to be rotatable about its central axis, and is rotated by being connected to a rotating mechanism 17 such as a rotating shaft of a motor. You.

On the other hand, the mirror 13 and the objective lens 14 for condensing the exposure laser beam L are moved in a direction parallel to the radial direction of the support 20. Thus, the rotation of the substrate 15 by the support unit 20 and the mirror 13
In cooperation with the movement of the objective lens 14, relative movement means for moving and scanning the exposure laser beam L in the photoresist layer 16 is formed. It is desirable that the objective lens 14 and the substrate 15 are made of a transparent material having the same refractive index with respect to exposure light.

The fixed transparent shielding plate 21 is configured to maintain a stationary state without being affected by the rotation of the support portion 20, that is, the substrate 15. In the illustrated example, this fixed transparent shielding plate 2
The first transparent liquid 31 is disposed on the first transparent liquid 31 by the fixed transparent shielding plate 21 and the side wall 101.
Is accommodated.

The first transparent liquid 31 is filled between the objective lens 14 and the fixed transparent shielding plate 21. Further, a space between the fixed transparent shielding plate 21 and the substrate 15 on which the photoresist layer 16 is applied is filled with a second transparent liquid 32. These first and second transparent liquids 31 and 3
2 has light transmittance to the exposure light.

The fixed transparent shielding plate 21 can be made of, for example, quartz glass. The fixed transparent shielding plate 21 is made of a transparent substrate having a refractive index equal to or close to that of the objective lens 14. The first transparent liquid 31 and the second transparent liquid 32 have a refractive index closer to the refractive index of the objective lens 14 than the refractive index of air, and each of the substrate 15 and the fixed transparent shielding plate 21 has a different refractive index. Liquids having a similar refractive index, for example benzene, can be used.

When the substrate support 20 is rotated by the rotating mechanism 17 when exposing the photoresist layer 16, the second transparent liquid 32 is exposed to the light from the exposure apparatus 10.
A guard mechanism 22 is provided so as not to be scattered outside. In addition, the second transparent liquid 32 is the fixed transparent shielding plate 2.
1 and the substrate 15, and the water surface of which is not involved in the exposure of the fixed transparent shielding plate 21.
The outer peripheral portion is filled so as to go around the upper portion of the fixed transparent shielding plate 21.

In order to prevent the second transparent liquid 32 from going around the side surface of the substrate 15 and entering the photoresist layer 16 side, for example, an O-ring 23 is arranged between the substrate 15 and the guard mechanism 22. I do.

A case will be described in which the photoresist 16 applied on the substrate 15 is exposed by using the exposure apparatus 10 for producing a master having the above-described configuration.

Exposure laser beam source 1 shown in FIG.
An exposure laser beam L is generated from 1 and the exposure laser beam L is modulated by the modulator 12 according to a predetermined exposure pattern. Then, the modulated exposure laser beam L is introduced into the objective lens 14 by the mirror 13 and condensed by the objective lens 14.

As shown in FIG. 2, the substrate 15 on which the photoresist 16 has been applied is mounted on a support section 20 which is rotated by a rotation mechanism 17, and is rotated at a predetermined rotation speed. At this time, the first transparent liquid 31 and the second transparent liquid 32 are blocked by the fixed transparent shielding plate 21. Since the fixed transparent shield plate 21 does not transmit the flow of the second transparent liquid that flows in accordance with the rotation of the substrate 15 to the first transparent liquid 31, the flow may occur in the first transparent liquid 31. And can be kept stationary. That is, the second transparent liquid 3 is fixed by the fixed transparent shielding plate 21.
The transmission of the flow of No. 2 to the objective lens 14 is avoided, and no shake or vibration occurs.

FIG. 3 is an enlarged view of a portion surrounded by an oval in FIG. As shown in FIG. 3, the second transparent liquid 3
Reference numeral 2 denotes an upper portion and a lower portion of the periphery of the fixed transparent shielding plate 21 which are arranged so as to communicate with each other at an outer peripheral portion of the fixed transparent shielding plate. As a result, the second transparent liquid 3 below the fixed transparent shielding plate 21 accompanying the rotation of the substrate 15 coated with the photoresist layer 16 is formed.
The movement in the outer peripheral direction due to the centrifugal force in 2 can be prevented by the second transparent liquid 32 arranged above the fixed transparent shielding plate 21.

That is, when the substrate 15 rotates, the fixed transparent shielding plate 21 and the photoresist layer 1 are rotated as shown in FIG.
The second transparent liquid 32 filled between the substrate 15 and the substrate 6 to which the liquid 6 is applied is drawn to the outer peripheral side by the centrifugal force generated by the rotation. The distance between the shielding plate 21 and the substrate 15 may fluctuate, or the fixed transparent shielding plate 21 may be damaged.

Since the distance between the fixed transparent shielding plate 21 and the substrate 15 is selected to be extremely small, the amount of the second transparent liquid 32 between the fixed transparent shielding plate 21 and the substrate 15 is small. Then, the fixed transparent shielding plate 21 and the substrate 15 are substantially in contact with each other.
The rotation of the camera makes it impossible to maintain a stationary state.

On the other hand, according to the configuration of the present invention described above,
The second transparent liquid 3 around the upper part of the fixed transparent shielding plate 21
2 is also attracted to the outer peripheral side by the centrifugal force generated by the rotation of the substrate 15, so that by adjusting the liquid amount of the second transparent liquid 32 above the fixed transparent shielding plate 21, the fixed transparent shielding plate described above is adjusted. It is possible to cancel the centrifugal force of the second transparent liquid 32 filled between the substrate 21 and the substrate 15 and to prevent the second transparent liquid 32 from moving in the outer peripheral direction. It is possible to prevent the amount of the second transparent liquid 32 from decreasing.

As described above, while the substrate 15 is rotated by the rotation mechanism 17, the incident exposure laser beam L is applied to the first and second transparent liquids 31 and 3.
2. The light is condensed on the photoresist 16 via the fixed transparent shielding plate 21 and the substrate 15 and is exposed to light to form fine irregularities. Thereafter, the surface is plated with, for example, Ag to produce a master. A stamper for transferring fine irregularities of an optical recording medium is formed by applying metal plating to the master thus manufactured and peeling it off or by repeating the metal plating.

As described above, when the photoresist is exposed through the first and second transparent liquids 31 and 32 between the objective lens for condensing the exposure light and the photoresist, these refractions are obtained. Since the refractive index can be larger than the refractive index of air, the spot diameter of the exposure beam L can be reduced as described in FIG. 6 and (Equation 1). This enables more precise exposure control. In the above-described embodiment, benzene is used as the first and second transparent liquids 31 and 32,
The refractive index of this benzene is 1.5. Therefore, according to (Equation 1), the diameter of the exposure beam L is reduced to 1 / 1.5 as compared with the case where exposure is performed through air. That is, from the viewpoint of the information recording density of the optical recording medium, it is possible to increase the linear density by 1.5 times and the areal density by 2.25 times.

In particular, in the present invention, the second transparent liquid 32 between the objective lens 14 and the second transparent liquid 32 in which the flow is generated by the rotation of the substrate 15 coated with the photoresist layer 16 is provided. Since the fixed transparent shielding plate 21 having the effect of not transmitting the flow of the light 32 to the objective lens 14 is provided, the first transparent liquid 31 in contact with the objective lens 14 is provided.
Does not occur despite the relative movement of the substrate 15 and the objective lens 14, so that the objective lens 14 can be stably and reliably moved to a predetermined position with a predetermined pattern without causing an axial deviation or the like. Can be performed.

In the above-described embodiment, the case where the same one, that is, benzene is used as the first transparent liquid 31 and the second transparent liquid 32 has been described. However, the present invention is not limited to this example. Different liquids can be used as long as these transparent liquids have light transmittance to exposure light and have the same refractive index.

In the above-described embodiment, the 15 coated with the photoresist layer 16 is arranged such that the side coated with the photoresist layer is opposite to the side facing the objective lens 14, and the second transparent Although the case where the liquid 32 is not in contact with the liquid 32 has been described, the present invention is not limited to this example, and the substrate 15 is arranged such that the photoresist layer 16 is on the side facing the objective lens 14. Thus, a configuration in which the second transparent liquid 32 is in contact with the second transparent liquid 32 may be employed. However, in this case,
Second transparent liquid 3 in direct contact with photoresist layer 16
2 needs to use an insoluble in the photoresist 16. As described above, when the substrate 15 is placed so that the photoresist layer 16 faces the objective lens 14, the exposure can be performed with the photoresist layer 16 and the objective lens 14 closer to each other than in the above-described embodiment. Therefore, a finer pattern can be exposed.

[0041]

According to the present invention, the immersion method is adopted in the exposure apparatus for producing a master for an optical recording medium, whereby the light condensing power of the exposure laser beam L can be improved. Also, by providing the fixed transparent shielding plate between the substrate and the objective lens, the flow of the first liquid due to the rotation of the substrate is not transmitted to the objective lens despite the liquid immersion method. As a result, it was possible to effectively avoid the axial blur of the objective lens and the disturbance of the autofocus operation.

The substrate 15 is placed so that the photoresist layer 16 faces the objective lens 14, and the photoresist is brought into contact with the second transparent liquid 32. In addition, since exposure can be performed with the distance to the objective lens 14 closer, exposure of a finer pattern can be performed.

Further, according to the present invention, the second transparent liquid 32 is
The upper and lower portions of the fixed transparent shielding plate 21 communicate with each other at the outer periphery of the fixed transparent shielding plate.
By adjusting the amount of the second transparent liquid 32 above the second transparent liquid 32 below the fixed transparent shielding plate 21 as the substrate 15 coated with the photoresist layer 16 rotates.
In the outer peripheral direction due to the centrifugal force can be prevented by the centrifugal force generated by the rotation of the substrate of the second transparent liquid 32 on the upper part of the fixed transparent shielding plate 21, and the fixed transparent shielding plate 21 and the substrate 15 During this period, the amount of the second transparent liquid 32 can be prevented from being reduced.

[Brief description of the drawings]

FIG. 1 shows a schematic configuration diagram of a master exposure apparatus according to the present invention.

FIG. 2 is a schematic configuration diagram of a main part of a master exposure apparatus according to the present invention.

FIG. 3 is a schematic configuration diagram of a main part of a master exposure apparatus according to the present invention.

FIG. 4 is a schematic configuration diagram of a conventional master exposure apparatus.

FIG. 5 shows a schematic configuration diagram of a main part of a conventional master exposure apparatus.

FIG. 6 is a schematic configuration diagram of a main part of a conventional master exposure apparatus when a liquid immersion method is used.

[Explanation of symbols]

10, 50 master exposure apparatus, 11, 51 exposure laser beam source, 12, 52 modulator, 13, 53 mirror, 14, 54 objective lens, 15, 55 substrate, 1
6,56 photoresist, 17 rotating mechanism, 20 substrate support, 21 fixed transparent shielding plate, 22 guard mechanism,
23 O-ring, 100 Exposure mechanism of master exposure tool, 1
01 Cylindrical side wall

Claims (9)

[Claims] An exposure apparatus for producing a master of an optical recording medium for forming fine irregularities on an optical recording medium, comprising: a support portion for a substrate coated with a photoresist layer; an objective lens for exposure light; A fixed transparent shielding plate having liquid tightness is disposed between the substrate on which the photoresist layer is applied, and at least one of the objective lens or the support portion of the substrate, passing through the objective lens. And a relative moving means for moving and scanning the exposure spot arriving at the photoresist layer in the photoresist layer, between the objective lens and the fixed transparent shielding plate, and between the fixed transparent shielding plate and the photoresist. A first transparent liquid and a second transparent liquid having light transmittance to the exposure light are filled between the substrate and the substrate coated with the resist layer. Master fabrication exposure apparatus Manabu recording medium. 2. The exposure apparatus according to claim 1, wherein the supporting portion of the substrate comprises a rotating support for rotating the substrate in a plane thereof. 3. The liquid crystal according to claim 1, wherein the first and second transparent liquids have a refractive index closer to that of the objective lens than that of air. 2. An exposure apparatus for producing a master of an optical recording medium according to 1. 4. The first and second transparent liquids, the substrate on which the photoresist layer has been applied, and the fixed transparent shield plate have the same refractive index with respect to the exposure light. The exposure apparatus for producing a master of an optical recording medium according to claim 1, wherein: 5. The exposure apparatus according to claim 1, wherein the first and second transparent liquids are made of the same transparent liquid. 6. The substrate on which the photoresist layer is applied is constituted by a substrate having a light transmitting property with respect to the exposure light, and the photoresist layer is provided on a side opposite to a side facing the objective lens. 2. The exposure apparatus according to claim 1, wherein the exposure apparatus is arranged so as not to contact the second transparent liquid. 7. The method according to claim 1, wherein the substrate coated with the photoresist layer and the objective lens are made of a transparent material having a refractive index equivalent to that of the exposure light. An exposure apparatus for producing a master of an optical recording medium. 8. The substrate coated with the photoresist layer, wherein the photoresist layer is disposed on a side facing the objective lens so as to come in contact with the second transparent liquid, 2. The transparent liquid according to claim 1, wherein the photoresist layer comprises a transparent liquid that does not exhibit solubility.
An exposure apparatus for producing a master of an optical recording medium according to item 1. 9. The second transparent liquid is disposed so as to communicate with an upper portion and a lower portion of the fixed transparent shielding plate at an outer peripheral portion of the fixed transparent shielding plate, and the second transparent liquid is coated with the photoresist layer. Movement of the second transparent liquid in the lower part of the fixed transparent shielding plate in the outer peripheral direction due to centrifugal force accompanying rotation of the substrate is performed by the second upper part of the fixed transparent shielding plate.
3. The exposure apparatus for producing a master of an optical recording medium according to claim 2, wherein the exposure is performed by a transparent liquid.