JPH06176408A - Exposure device of rotary scanning system - Google Patents

Abstract

PURPOSE:To expose patterns with high accuracy over the entire surface on a circular disk surface by will maintaining the flatness of a circular reticule. CONSTITUTION:The circular reticule R is imposed on the holding part 4 of a rotary driving section 3 and a flat plate 5 is disposed on the circular reticule R apart a slight spacing therefrom. Gas of a prescribed pressure is supplied between the flat plate 5 and the circular reticule R via a through-hole 5c in the central part of the flat plate 5. The circular reticule R is attracted to the plane plate 5 by Bernoulli theorem, by which the deflection of the circular reticule R is corrected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary scanning type exposure apparatus suitable for use in producing a disk-shaped medium such as a compact disk (CD) or a video disk (VD) in a lithography process. .

[0002]

2. Description of the Related Art Conventionally, compact discs (CDs),
When manufacturing a disc-shaped recording / reproducing medium such as a video disc (VD), pattern information for forming grooves or pits is directly formed on a master disc using a laser spot, and the master disc is replicated on an electroformed stamper. Was being duplicated. Then, by the stamping from the electroformed stamper, the disk-shaped medium of the product level of CD and VD has been mass-produced. However, in this manufacturing method, the groove or pit width or interval is 0.5 to
If the size is reduced to about 0.3 μm, it becomes difficult to accurately copy the groove or pit.

Therefore, as a method of forming a fine concentric or spiral pattern by a disk-shaped medium, the applicant of the present invention discloses a method of manufacturing the disk-shaped medium in a lithographic process in Japanese Patent Application No. 3-34257. Proposed. In the manufacturing method according to the prior application of the applicant, first, in a state in which an original plate of a disk-shaped medium and the disk-shaped medium are rotated in synchronization with each other by a rotary scanning type exposure device, the pattern of the original plate has a predetermined circle. The disc-shaped medium coated with the photosensitive material is exposed for each circumferential angle. Then, by performing processing such as development on the disc-shaped medium that has been exposed to the entire circumference, concentric or spiral patterns (grooves or pits) are formed as concavo-convex patterns on the disc-shaped medium. .

FIG. 3 shows a schematic structure of a rotary scanning type exposure apparatus according to the prior application of the present applicant. In FIG.
The condenser lens 1 forming a part of the illumination optical system emits exposure light for illuminating a ring-shaped original image pattern area PA of a circular reticle R as a master of a disk-shaped medium with a fan-shaped illumination area IA. The origin of the fan-shaped illumination area IA substantially coincides with the central axis of the ring pattern area PA, that is, the rotation axis C1 of the circular reticle R. Then, the projection optical system PL causes the pattern image on the fan-shaped illumination area IA in the original image pattern area PA to be a photosensitive material (photoresist or the like).
Is projected onto a circular disk plate D coated with.

In the projection optical system PL using a normal refraction system,
Since the pattern on the object side is projected as an inverted image (mirror image), the rotation axis C2 of the circular disc plate D is set to the projection optical system PL.
Is located on the opposite side of the rotation axis C1 of the circular reticle R with the optical axis AX of the above. In this state, the circular reticle R is rotated clockwise by φ1 by the rotary drive system RRC, and the circular disc plate D
Is rotated in the counterclockwise direction φ2 by the rotary drive system DRC. At this time, the main control system MCU controls the circular reticle R and the circular disc plate D to rotate at the same angular velocity. Then, in the state where the angular velocities are the same, the exposure light is irradiated from the illumination optical system into the fan-shaped illumination area IA, and thereafter, the circular reticle R and the circular disc plate D are integrated only once (including once). The exposure is stopped after rotating.

As a result, the latent image of the entire ring-shaped original image pattern area PA is transferred to the photosensitive material layer on the surface of the circular disc plate D, and then the circular disc plate D is developed and etched (or vaporized). By passing through the process of (1), a fine concavo-convex pattern which forms a circular track composed of grooves or pit rows is engraved on the circular disk plate D.

FIG. 4 shows a more detailed structure of the exposure apparatus of FIG. 3, in which exposure light from an illumination system 10 including a light source such as a mercury lamp or an excimer laser light source is reflected by a mirror 2. It enters the condenser lens 1. A circular opening centering on the rotation axis C1 is formed at the center of the circular reticle R, and the rotation axis 21 of the reticle rotation support mechanism 20 is engaged with the circular opening. Further, the reticle rotation support mechanism 20 is provided with a rotary drive system RRC for rotating the circular reticle R via the rotary shaft 21. The rotary shaft 21 has a circular opening at the center of the circular reticle R, which is sandwiched from above and below to form the circular reticle R.
, And the reticle rotation support mechanism 20 is U-shaped as a whole.

Further, the reticle rotation support mechanism 20 includes a shaft 2
The circular reticle R is rotatably connected to the sub-column 22 via 0A, and when the circular reticle R is replaced, the circular reticle R is conveyed outside the projection light exposure by rotating the reticle rotation support mechanism 20 about the shaft 20A. To be done. Sub column 22
Is arranged by a motor, a piezo element, etc. so that it can be finely moved in a horizontal direction with respect to a main column (not shown) holding the projection optical system PL, and the fine movement is performed by a command from the main control system MCU. This is for accurately aligning the fan-shaped illumination area IA by the illumination optical system and the ring-shaped original image pattern area PA of the circular reticle R.

On the other hand, on the circular disc plate D, the rotation axis C2
An opening is formed around the axis, and the circular disc plate D is fixed by vacuum suction or the like on a rotary table 30 having a pivot-shaped central protrusion fitted in the opening. The rotary table 30 is rotated by the rotary drive system DRC, and the rotary table 30 and the rotary drive system DRC are horizontally (in the plane defined by the left-right direction of the paper surface of FIG. 4 and the direction perpendicular to the paper surface of FIG. 4). The laser beam is placed on a movable XY stage 40, and the movement amount of the XY stage 40 is determined by the laser interferometer 4.
2 is always detected. In this way, the laser interferometer 42 is provided so that when the circular disc plate D is exchanged, the rotary table 30 is retracted from directly under the projection optical system PL to provide an unprocessed circular disc plate and an exposed circular disc plate. Because it is necessary to replace. Further, it is necessary to accurately return the XY stage 40 to the original exposure position again after exchanging the circular disc plate. The measurement value of the laser interferometer 42 is supplied to the main control system MCU, and the main control system MCU controls the motor for positioning the XY stage 40 based on the measurement value.

Further, in FIG. 4, a sensor 50 for detecting the parallelism (perpendicularity to the optical axis AX) of the circular reticle R during rotation, and an air for adjusting the parallelism of the reticle R during rotation. A leveling mechanism 60 such as a bearing type is provided. Similarly, for the circular disc plate D, a sensor 70 for detecting parallelism is provided,
Detection signals from the sensors 50 and 70 are supplied to the focus control system 80. The focus control system 80 controls the leveling mechanism 60 and a mechanism (not shown) that finely moves the rotary table 30 in the direction of the optical axis AX for focusing.

As described above, in the exposure apparatus shown in FIGS. 3 and 4, the circular reticle R and the circular disc plate D are rotated in synchronization with each other, and the pattern in the fan-shaped illumination area IA of the circular reticle R is formed. By projecting on the exposure surface of the circular disc plate D, the circular pattern is exposed to the entire circumference of the circular disc plate D. Also, as shown in FIG.
Although the leveling mechanism 60 is provided, its function is mainly to guide the rotation of the circular reticle R, and the function of correcting the deflection of the circular reticle R was weak. Therefore, in principle, the circular reticle R must maintain the flatness due to the rigidity of the reticle itself, and the thickness and material of the reticle are restricted.

[0012]

In the prior art as described above, the circular reticle R is bent depending on the thickness, material, size, etc. of the circular reticle R, and the imaging performance of the projection optical system PL. There was an inconvenience that it deteriorated. In particular, when the original image pattern of a large area circular reticle is exposed on a circular disk, the deflection at the peripheral edge of the circular reticle becomes large, and the pattern image projected at the central portion and the peripheral edge of the circular reticle R. The image forming characteristics of No. 2 may change significantly, and the yield of the circular disc plates D may be greatly reduced.

In view of the above-mentioned problems, the present invention provides a rotary scanning type exposure apparatus capable of accurately maintaining the flatness of a circular reticle and exposing a pattern on all exposed surfaces of a photosensitive substrate with high accuracy. To aim.

[0014]

A rotary scanning type exposure apparatus according to the present invention exposes a concentric or spiral pattern on a photosensitive disk (D) as shown in FIGS. 1 and 3, for example. In the apparatus, a mask substrate (R) having an original pattern corresponding to a concentric circular pattern or a spiral pattern to be formed on a photosensitive disc (D) is formed around a predetermined axis (C1). A first rotation holding means (RRC) for rotatably holding (C1) as a rotation center;
Of the non-contact bending correction means (5) for correcting the bending of the mask substrate (R) held by the rotation holding means without contacting the mask substrate (R), and the original image pattern of the mask substrate (R). Illuminating means (1) for illuminating, with exposure light, a slit-shaped or fan-shaped illumination area within a range of a predetermined circumferential angle around a predetermined axis (C1).

Further, according to the present invention, a projection optical system (PL) for projecting an image in the slit-shaped or fan-shaped illumination area of the original image pattern on a predetermined image forming plane, and a photosensitive disc (D).
Of the photosensitive disk (D) is substantially conjugate with the predetermined axis (C1) of the mask substrate (R) with respect to the projection optical system (PL). The photosensitive disc (D) at the center point (C2).
Second rotation holding means (DRC) for rotating about the axis
Drive control means (M) for driving the first and second rotation holding means in synchronization so that the mask substrate (R) and the photosensitive substrate (D) rotate in synchronization at substantially equal angular velocities.
CU), a mask substrate (R) and a photosensitive disc (D)
The image of the original image pattern is exposed on the photosensitive disc (D) in a state where they are rotated in synchronization with each other.

In this case, the non-contact deflection correcting means is
As an example, the reference plane plate (5) is composed of a gas supply means for circulating a gas between the reference plane plate (5) and one surface of the mask substrate (R), and the reference plane plate ( By making one surface of the mask substrate (R) follow the 5) side, the bending of the mask substrate (R) is corrected. In addition, as another example, the non-contact deflection correction means is, for example, as shown in FIG. 2, a gas ejection means (9) for blowing a gas onto one surface of the mask substrate (R), and the mask is operated by the pressure of the gas. This is to correct the bending of the substrate (R).

[0017]

According to the present invention, the flatness of the mask substrate (R) is favorably maintained by the non-contact deflection correcting means. Therefore, the image of the original image pattern of the mask substrate (R) is transferred to the entire exposed surface of the photosensitive disc (D) with a good image forming characteristic while the rotation accuracy of the mask substrate (R) is maintained well. It

Further, the non-contact deflection correcting means is composed of the reference plane plate (5), the reference plane plate (5) and the mask substrate (R).
In the case of a gas supply means for circulating a gas between the mask substrate (R) and the reference plane plate (5), a mask substrate ( R) is attracted to the reference plane plate (5). Therefore, the flatness of the mask substrate (R) is corrected by the reference flat plate (5), and the flatness of the mask substrate (R) is maintained well.

When the non-contact deflection correction means is gas ejection means (9) for blowing gas onto one surface of the mask substrate (R), the flatness of the mask substrate (R) is caused by the pressure of the gas. Is maintained well.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a rotary scanning type exposure apparatus according to the present invention will be described below with reference to FIG. The present embodiment is an improvement of the rotary holding portion of the circular reticle R of the exposure apparatus shown in FIGS.
Only the configuration of the rotation holding unit will be described.

FIG. 1A is a perspective view of a rotation holding portion of the circular reticle R of this embodiment, and FIG. 1B is a sectional view of the rotation holding portion. These rotation holding portions are shown in FIGS. 1A and 1B. In, the circular reticle R is held on the holding part 4 connected to the rotary drive part 3, and the flat plate 5 is arranged on the circular reticle R with a slight distance. A fan-shaped opening 5a is provided in a part of the plane plate 5, and the fan-shaped illumination area IA of FIG. 3 is set in the opening 5a.

Further, a protrusion 5b is provided on the upper part of the central portion of the flat plate 5.
A gas such as air is rapidly supplied between the flat plate 5 and the circular reticle R from an external gas supply source (not shown) through the through hole 5c in the projection 5b. This gas is temperature-controlled and passes through a dust collecting filter. The surface of the plane plate 5 facing the circular reticle R is finished into a highly accurate plane. Further, a displacement sensor 6 for detecting the distance from the circular reticle R in a non-contact manner is arranged below the radial end of the circular reticle R, and a detection signal of the displacement sensor 6 is supplied to the control device 7. . The control device 7 controls the flat plate 5 from the gas supply source so that the distance from the circular reticle R detected by the displacement sensor 6 is maintained within a predetermined range.
Adjust the pressure of the gas supplied to.

According to this embodiment, the circular reticle R is attracted to the flat plate 5 by Bernoulli's principle by supplying the gas between the flat plate 5 and the circular reticle R through the through hole 5c of the flat plate 5. Thus, the bending of the circular reticle R is corrected. Further, the deflection of the circular reticle R is measured by the displacement sensor 6, and the gas supply pressure is adjusted by the control device 7 according to the change in the amount of the deflection, whereby the flatness of the circular reticle R is always maintained with high accuracy. It In particular, in the rotary scanning type exposure apparatus, when the angular velocity of the circular reticle R in the φ1 direction is switched, the deflection amount of the circular reticle R may change. A mechanism for adjusting the pressure of the gas to be supplied is effective.

As described above, according to the present embodiment, the flatness of the circular reticle R can be maintained with high accuracy, and the pattern image of the circular reticle R can be formed with high accuracy on the entire exposed surface of the circular disc plate D of FIG. Can be exposed to light. Further, by flowing a temperature-controlled clean gas onto the upper surface of the circular reticle R, foreign matter is prevented from adhering to the circular reticle R, and the circular reticle R is irradiated by exposure light from the illumination optical system.
It is also possible to suppress the temperature rise. Further, by tilting the plane plate 5, the circular reticle R can be tilted without contacting the circular reticle R while the circular reticle R is being rotated, and the projected image can be corrected.

Next, another embodiment of the present invention will be described with reference to FIG. The present embodiment also applies the present invention to the rotation holding unit of the circular reticle R of the rotary scanning type exposure apparatus of FIGS. FIG. 2 is a cross-sectional view of the rotary holding part of the circular reticle R of this example. In FIG. 2, the circular reticle R is held on the holding part 4 connected to the rotary drive part 3, and the circular reticle R is held above the circular reticle R. The flat plate 8 is arranged at a slight interval. A fan-shaped opening (corresponding to the opening 5a in FIG. 1A) is provided in a part of the flat plate 8, and the fan-shaped illumination area IA in FIG. 3 is set in this opening. A large number of through holes 8 are formed in the vicinity of the peripheral edge of the plane plate 8.
a, 8b, ..., and through holes 8a, 8b ,.
A gas having a predetermined pressure, which is temperature-controlled by an external gas supply source (not shown) and has passed through the dust collecting filter, is supplied between the flat plate 8 and the circular reticle R via. Through holes 8
The concave gas reservoirs 8c, 8d, ... With respect to the circular reticle R are formed on the gas ejection side of a, 8b ,.

Further, a plane plate 9 is also arranged below the circular reticle R with a slight gap. A fan-shaped opening in a part of the flat plate 9 (corresponding to the fan-shaped opening in the flat plate 8)
And a large number of through holes 9a near the peripheral edge of the flat plate 9,
9b, ..., and through the through holes 9a, 9b, ... Between the flat plate 9 and the circular reticle R, the temperature is controlled by an external gas supply source (not shown) Supply gas at pressure. This lower flat plate 9
The pressure of the gas supplied from the to the circular reticle R is set to be larger than the pressure of the gas supplied from the upper flat plate 8 to the circular reticle R. Those through holes 9a, 9b,
.. are also formed on the ejection side of the gas with respect to the circular reticle R. The gas reservoirs 9c, 9d ,. Further, the rotation drive unit 3 is housed in the central opening 9e of the lower flat plate 9,
If necessary, for example, the rotary shaft 21 of FIG. 4 is housed in the central opening 8e of the upper flat plate 8.

According to this embodiment, the flat plate 8 and the flat plate 9 are provided.
The flat surface of the circular reticle R follows the flat plate 8 and the flat plate 9 by supplying gas of a predetermined pressure to the flat plate 8 and the flat plate 9 from the flat plate 8 and the flat plate 9 respectively. The flatness of the reticle R is maintained with high accuracy. In the embodiment shown in FIG. 2, a gas having a small pressure is supplied to the circular reticle R also from the upper flat plate 8, but the flat plate 5 shown in FIG. You may. In this case, the lower flat plate 9
On the other hand, since the circular reticle R is lifted and the circular reticle R is attracted to the upper flat plate, the effect of correcting the bending of the circular reticle R is increased.

As described above, the present invention is not limited to the above-mentioned embodiments, and various configurations can be adopted without departing from the gist of the present invention.

[0029]

According to the present invention, the flatness of the mask substrate can be maintained with high accuracy by the non-contact deflection correcting means, and the entire surface of the photosensitive disk can be exposed with high accuracy. There are advantages. Further, since the flatness of the mask substrate is maintained regardless of the rigidity of the mask substrate, the mask substrate can be thinned. Therefore, handling of the mask substrate becomes easy, and the cost of the mask substrate can be reduced.

Further, in the case where the non-contact deflection correcting means corrects the deflection of the mask substrate by causing one surface of the mask substrate to follow the reference plane plate side by the negative pressure of gas, For example, by flowing a clean gas whose temperature is controlled to the surface of the mask substrate, it is possible to prevent foreign matter from adhering to the mask substrate and suppress the temperature rise of the mask substrate due to the irradiation of the exposure light from the illumination optical system. Further, by tilting the reference plane plate, the mask substrate can be tilted without contacting the mask substrate while the mask substrate is being rotated, and the projected image can be corrected.

Further, the same advantage can be obtained when the non-contact bending correction means corrects the bending of the mask substrate by the pressure of gas.

[Brief description of drawings]

FIG. 1A is a perspective view showing a rotary holding portion of a circular reticle of an embodiment of a rotary scanning type exposure apparatus according to the present invention;
1B is a sectional view of FIG.

FIG. 2 is a sectional view showing a rotation holding portion of a circular reticle according to another embodiment of the present invention.

FIG. 3 is a perspective view showing a schematic configuration of a rotary scanning type exposure apparatus according to a prior application of the present applicant.

4 is a configuration diagram including a partial cross-sectional view showing a more detailed structure of the exposure apparatus of FIG.

[Explanation of symbols]

 1 Condenser lens R Circular reticle 3 Rotation drive unit 4 Holding unit 5 Plane plate 6 Displacement sensor 7 Control device 8, 9 Plane plate 10 Illumination system PL Projection optical system D Circular disc plate RRC, DRC Rotation drive system MCU Main control system

Claims (3)

[Claims] 1. An apparatus for exposing a concentric or spiral pattern on a photosensitive disc, wherein an original image pattern corresponding to the concentric or spiral pattern to be formed on the photosensitive disc has a predetermined axis. A first rotation holding unit that holds the mask substrate formed around the rotatably centered around the predetermined axis, and a bending of the mask substrate held by the first rotation holding unit. Non-contact deflection correction means for correcting without touching the mask substrate, and a slit-shaped or fan-shaped illumination area within a range of a predetermined circumferential angle about the predetermined axis in the original image pattern of the mask substrate Illuminating means with exposure light, an image in the slit-shaped or fan-shaped illumination area of the original image pattern, a projection optical system for projecting in a predetermined image plane, the exposure surface of the photosensitive disk Within the image plane In addition, the photosensitive disk is rotated about the center point while the center point of the photosensitive disk is arranged at a position substantially conjugate with a predetermined axis of the mask substrate with respect to the projection optical system. A second rotation holding means, and a drive control means for driving the first and second rotation holding means in synchronization so that the mask substrate and the photosensitive disc rotate in synchronization at substantially equal angular velocities. An exposure apparatus of a rotary scanning system, which comprises exposing the image of the original image pattern on the photosensitive disc in a state in which the mask substrate and the photosensitive disc are rotated in synchronization with each other. 2. The non-contact deflection correction means includes a reference plane plate and a gas supply means for allowing a gas to flow between the reference plane plate and one surface of the mask substrate. 2. The rotary scanning type exposure apparatus according to claim 1, wherein the bending of the mask substrate is corrected by making one surface of the mask substrate follow the reference plane plate side. 3. The non-contact bending correction means is composed of a gas jetting means for blowing a gas onto one surface of the mask substrate, and corrects the bending of the mask substrate by the pressure of the gas. The rotary scanning type exposure apparatus according to claim 1.