JP2000098627A - Exposure method and exposing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture accurately a diffraction grating on a side surface of a rotary shaft of a motor, a side surface of a rotary shaft of a finger joint of a robot, and the like, directly. SOLUTION: A pattern on a mask 1 being an original plate is transcribed to a non-flat plane work 10. The mask 1 is moved in the prescribed direction in a state in which the mask 1 is irradiated with a luminous flux L from an exposure light source. And the pattern on the mask 1 is transcribed on the non-flat plane work 10 by rotating the non-flat plane work 10 by rotation quantity corresponding to movement of this mask 1. Thereby, exposure for performing accurate transcription on a non-flat plane work can be realized. Also, it is preferable that a mask is contacted with a non-flat work and the non-flat work is rotated in accordance with movement of a mask.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an exposure apparatus for directly drawing a diffraction grating or the like on a curved surface such as a rotation axis of a motor or a rotation axis of a finger joint of a robot.

[0002]

2. Description of the Related Art In general, an optical encoder is used as a device for detecting a rotation amount of a rotation axis of a motor or a finger joint of a robot. The optical encoder includes a light emitting unit that emits a light beam, two diffraction gratings that transmit the light beam, and a photoelectric conversion element that is disposed behind the two diffraction gratings. The amount of rotation and the amount of movement are detected based on a change in light intensity caused by the relative movement of the two diffraction gratings. In the optical encoder that detects the rotation angle, a disk-shaped scale on which a diffraction grating is engraved is arranged perpendicular to the rotation axis. Therefore, when detecting the amount of rotation of the rotation axis of the motor or the rotation axis of the finger joint of the robot, it is necessary to arrange the disk-shaped scale at the end of the rotation axis.

On the other hand, there is a case where it is desired to arrange a scale in the middle of a shaft, and there is a method of configuring the scale as a hollow structure. However, in this method, the scale is arranged around the rotation axis, so that the scale occupies a wide cross section, which hinders miniaturization.
In addition, since the rotating shaft and scale are connected via various mechanisms, there is a problem in vibration resistance, a problem such as thermal distortion due to a difference in thermal expansion coefficient between the rotating shaft and the scale, and deterioration in accuracy due to these. was there.

[0004] In order to solve these problems, a technique of directly drawing a diffraction grating on a cylindrical surface of a rotating shaft or the like has been conventionally proposed. An exposure method according to this conventional technique will be described. The mask on which the fine pattern is engraved is made of a flexible and ultraviolet-permeable material called a flexible mask. A thin film of a non-transmissive material such as chromium is formed on a flexible mask. Then, only chromium is finely processed by a photolithography process, and a fine pattern is formed on the flexible mask. This mask is attached to a non-planar surface such as a cylindrical surface to which a resist is applied. By exposing it with an ultraviolet light source or the like in the attached state, the resist on the cylindrical surface is exposed so as to transfer the pattern of the mask.

[0005]

However, in this conventional method, it is difficult to mount the flexible mask precisely on a non-planar surface because the flexible mask expands and contracts. There was a problem that can not be.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an exposure method for precisely forming a fine pattern on a surface of a non-planar metal or the like. .

[0007]

SUMMARY OF THE INVENTION The present invention relates to an exposure method and apparatus for forming a fine pattern on a non-planar surface. While exposing, the mask is linearly moved, and the non-planar workpiece to be exposed on which a fine pattern is to be formed is rotated in synchronization with the movement of the mask. Thereby, exposure for performing precise transfer on a non-planar work can be realized. Further, it is preferable that the non-planar work is brought into contact with the mask, and the non-planar work is rotated according to the movement of the mask. It is also preferable to provide a rotating means for the non-planar work, and to synchronously control the movement of the mask and the rotation of the rotating means. Further, it is preferable to provide a spacer contact surface on the surface of the mask or the non-planar work for maintaining a constant gap between the mask and the pattern forming surface of the non-planar work surface.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention (hereinafter, referred to as embodiments) will be described below with reference to the drawings. FIG. 1 is a structural view of an exposure apparatus according to a first embodiment of the present invention.
Light source (not shown), a mask 1 on which a pattern to be a pattern to be transferred is engraved, and a roller 11 for supporting a workpiece 10 to be exposed so as to rotate in accordance with the movement of the mask 1 , A slit 13 for limiting the light beam L emitted from the light source, and a mask moving means 20 for linearly moving the mask 1. Mask 1
Is pressed against the work 10 by a downward force in the figure. Accordingly, the mask 1 and the work 10 to be exposed are in contact with each other, and the work 10 to be exposed rolls and rotates with the linear movement of the mask 1 by the mask moving means 20 for linearly moving the mask 1. As a result, the work 10 to be exposed is rolled so that the linear movement amount of the mask 1 and the rotational movement amount on the circumference of the work 10 to be exposed become equal. In such a configuration, the light flux L such as ultraviolet light emitted from the light source is restricted by the slit 13 and the mask 1 and the work 1
0 is applied to a region that is in close contact or in proximity. On the other hand, a resist 12 is applied to the cylindrical side surface of the cylindrical work 10, and the resist applied surface of the cylindrical work 10 is sequentially exposed and the mask pattern is transferred according to the movement of the mask 1. The width of the slit 13 is determined in consideration of the intensity of the exposure light. The intensity of the exposure light is slightly different between a region where the mask 1 and the work 10 are in close contact and a region where the mask 1 is in close proximity. In order to maintain the contrast of the pattern on the resist-coated surface at 0.7 or more, the size Z of the gap between the mask 1 to be irradiated with the light beam and the surface of the work 10 may be suppressed within the range of the following expression. The width of the slit may be determined in advance.

[Number 1] Z ≦ P ² / 64λ where, P is the period of the grating pattern on the mask, lambda is the wavelength of the light beam. In the process after exposure, a pattern is formed by a normal photolithography process, and a diffraction grating is formed on the cylindrical side surface of the work 10. Since the diffraction grating is a reflection type diffraction grating, the configuration as an encoder is as follows.
What is necessary is just to comprise as a general reflection type optical encoder. When a diffraction grating is formed on a transmission material, it may be configured as a transmission optical encoder. Here, mask 1
It is preferable that a metal pattern such as Cr is formed on a rigid transparent substrate such as glass, resin or silicon. Further, as the mask moving means 20, various types such as those using a servomotor or a stepping motor can be adopted. The moving speed of the mask 1 can be moved accurately,
The exposure time may be set so as to obtain an appropriate exposure time.

Next, a second embodiment which further improves the above-described embodiment will be described with reference to FIG. In the exposure apparatus described above with reference to FIG. 1, when a very fine diffraction grating pattern is transferred over the work to be exposed 10 over one round, it is difficult to ensure the pattern connection accuracy at the start and end points of the transfer. There is. The reason is that mask 1
Is rolled so that the amount of linear movement of the work to be exposed and the amount of rotational movement on the circumference of the work to be exposed 10 are equal, so that the work to be exposed 10 makes one rotation (circumferential length). This is because it is necessary to precisely match the length of the mask pattern. Therefore, in order to reduce the joint error at one peripheral portion of the transfer pattern, the exposure work 1
It was necessary to keep the precision of the diameter of 0 within a certain precision.

In order to improve these problems, in the second embodiment, the mask 1 and the work 10 to be exposed are not in contact with each other, and their movements and rotations are controlled synchronously. On the rotating mechanism side of the work 10, the work 1
Work rotating means 21 for rotating 0 is provided,
The mask 1 and the work 10 to be exposed are not in contact with each other.
Further, there is provided a synchronization control section 22 for synchronously controlling a mask moving means 20 for linearly moving the mask 1 and a work rotating means 21 for precisely controlling the rotation angle of the work 10. For example, when transferring a grid pattern of 100 μm pitch on a mask onto the side surface of a cylindrical workpiece to be exposed at a rate of 100 grid patterns per rotation, the mask moving unit 20 moves by 10 mm (100 μm × 100). I do. On the other hand, the work rotating unit 21 makes one rotation, and the synchronization control unit 22 synchronizes them. With this configuration, the amount of movement of the mask 1 and the amount of rotation of the workpiece 10 can be precisely synchronized. Therefore, the work 10 to be exposed
The distance (circumferential length) of one rotation of the pattern and the length of the corresponding mask pattern can be precisely matched, and no joint error occurs in the transfer pattern at one circumferential portion of the pattern. Also, even if there is an error in the diameter of the exposure work 10,
Since the movement amount of the mask 1 and the rotation amount of the work 10 are synchronized, a seam error does not occur independently of the influence. As described above, according to the present embodiment, it is possible to form the diffraction grating pattern while eliminating the joint problem, even if the accuracy of the diameter of the workpiece 10 to be exposed is not so high.

A third embodiment which further improves the second embodiment will be described with reference to FIG. In the second embodiment, the mask 1 and the work 10 are close to each other, and the mask 1 and the work 10 are kept parallel, and the exposure is performed at a distance of, for example, about 10 to 30 μm. It may change depending on the mechanical rotation accuracy of the work 10 to be exposed. Although the rotation accuracy of the work 10 can be controlled at the micron level, it requires a great care in this management, and its adjustment requires man-hours. If the gap amount between the mask 1 and the work 10 changes, the light intensity generated on the work to be exposed by irradiating the mask 1 changes, and the brightness and contrast of the transferred pattern change.

Therefore, in the third embodiment, the pattern forming surface on the work 10 to be exposed is not in contact with the mask 1, but the mask 1 or the work 10 to be exposed has a pattern forming surface. The gap between the mask 1 and the surface of the work to be exposed is kept constant. FIG. 3A shows an example in which the spacer contact surface 2 is used for the mask, and FIG. 3B shows an example in which the spacer contact surface 2 is used for the work 10 to be exposed. Mask 1
Is pressed against the work 10 in a downward direction in the figure with a force that keeps the gap constant. In the rotating mechanism, the mask 1 and the work 10 to be exposed are in contact with each other at a portion other than the pattern forming portion, but are not in the pattern forming portion. In this configuration, the mask 1 and the work 10 to be exposed are
The mask 1 is moved by the mask moving means 2
The rotation of the work 10 to be exposed is performed by the work rotating means 21. The contact on the spacer contact surface 2 is for maintaining a constant gap between the mask 1 and the pattern forming surface of the workpiece 10 to be exposed, and the displacement of the mask 1 and the workpiece 10 (the respective movement).
Is done to overcome this contact resistance. As a result, the mask 1 is precisely moved by the mask moving means 20 in a state where the gap is kept constant, and the rotation angle of the work 10 is precisely controlled in synchronism with the movement, so that one round of the pattern in the transfer pattern No joint error occurs, and the gap between the mask 1 and the work 10 does not change.
The brightness and contrast of the transfer pattern on the work to be exposed obtained when the mask is easily irradiated can be kept constant. Note that the height of the spacer contact surface may be variable.

The spacer contact surface 2 provided on the work shown in FIG. 3B may be removed after the transfer step. Further, depending on the material, the mask and the work may be precisely controlled in synchronization with the pattern forming surface being in contact with the spacer contact surface 2 without being provided.

The movement of the mask and the rotation of the work may be step operations instead of constant rotation or continuous rotation. The slit 13 is provided with a shutter, and the light beam to be exposed may be turned on and off as appropriate.

The work need not be a cylinder, and the present invention is not limited to the above embodiment.

[0016]

As described above, according to the present invention, a fine pattern can be precisely transferred onto a surface of a non-planar metal or the like. It can be directly and precisely transferred to a rotating shaft of the device and used as a scale of an encoder, so that the entire apparatus can be significantly reduced in size and performance can be improved.

[Brief description of the drawings]

FIG. 1 is a structural diagram showing a first embodiment of an exposure apparatus of the present invention.

FIG. 2 is a structural diagram showing a second embodiment of the exposure apparatus of the present invention.

FIG. 3 is a structural diagram showing a third embodiment of the exposure apparatus of the present invention.

[Explanation of symbols]

1 mask, 2 spacer contact surface, 10 work to be exposed, 11 roller, 12 resist, 13 slit,
20 mask moving means, 21 work rotating means, 22
Synchronous control unit.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Atsushi Atsushi 5-25-25 Shimokoguchi, Oguchi-machi, Niwa-gun, Aichi Prefecture Inside the Oguchi Plant of Okuma Corporation (72) Inventor Keiji Matsui 5-Shimoguchi, Oguchi-machi, Niwa-gun, Aichi Prefecture 1 25th Okuma Co., Ltd. Oguchi factory F-term (reference) 2H097 AA16 AB08 AB09 GA43 LA20

Claims (5)

[Claims] 1. An exposure method for transferring a pattern on a mask serving as an original onto a non-planar workpiece, the method comprising: moving the original mask irradiated with a light beam from an exposure light source in a predetermined direction; An exposure method, wherein the pattern on the mask serving as the original is transferred to the non-planar work by rotating the non-planar work by a corresponding rotation amount. 2. An exposure apparatus for transferring a pattern on a mask serving as an original onto a non-planar workpiece, a mask moving means for moving the mask in a predetermined direction, and a non-planar workpiece by a rotation amount corresponding to the movement of the mask. An exposure apparatus comprising: a rotating mechanism for rotating; a light source for irradiating light to a mask; and a slit for restricting a light beam emitted from the light source. 3. The exposure apparatus according to claim 2, wherein the rotating mechanism is configured so that the mask and the non-planar workpiece are in contact with each other, and the non-planar workpiece rotates according to the movement of the mask. 4. The exposure apparatus according to claim 2, wherein the rotation mechanism includes a rotation unit for the non-planar work, and the movement of the mask movement unit and the rotation of the rotation unit are controlled synchronously. 5. A method according to claim 5, wherein a surface of said mask or said non-planar work is provided with a spacer contact surface for keeping a constant gap between said mask and a pattern forming surface of said non-planar work. The exposure apparatus according to claim 2, wherein the exposure apparatus is not in contact with the exposure apparatus.