JPH0550281A - Optical processing device - Google Patents

Abstract

PURPOSE:To obtain the optical processing device which enable the user himself to form a dielectric thin-film mask having an arbitrary pattern. CONSTITUTION:This device has a 1st optical path which forms by shaping a laser beam 21 oscillated by a laser oscillator 1 to a prescribed shape by an aperture 4 formed with the desired pattern and by imaging this beam as the projected image of the aperture to the surface of a work 11 by an imaging means 5 and a 2nd optical path which has a processing stage 19 and images the image of a pinhole 13 to a processing position by an imaging lens 14. The device is so constituted as to form the pattern of the aperture by using the 2nd optical path.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical processing apparatus for forming a laser beam that has passed through an aperture on a surface of a workpiece by an image forming lens to perform fine processing of the workpiece.

[0002]

2. Description of the Related Art FIG. 2 is a block diagram showing a laser processing apparatus which is an example of a conventional optical processing apparatus. This device uses, as a light source, an ultraviolet laser beam having a high photon cost, such as an excimer laser, to effectively use the photons. For this reason, a multi-reflection optical system is used, a dielectric thin film is formed as an opening having high laser light resistance and high reflectance characteristics, and the laser light transmitted through this opening is formed on the surface of the workpiece by an imaging lens. It is an apparatus for forming an image on a substrate and processing the workpiece. In the figure, 1 is a laser oscillator, 2 is a beam shaping optical system, 3 is a total reflection mirror of a multiple reflection optical system, 4 is a mask mirror of the multiple reflection optical system, 5 is an imaging lens, 6 is a dichroic mirror, and 7 is a monitor. Optical system, 8 is CRT,
9 is a processing stage, 10 is a processing stage controller,
Reference numeral 11 is a processed sample that is a workpiece, and 21 is a laser beam. An opening is formed in a desired pattern on the mask mirror 4, and a dielectric thin film is formed on the surface of the total reflection mirror-3 side.

Next, the operation will be described. The laser beam 21 emitted from the laser oscillator 1 is adjusted to have an appropriate shape or an appropriate energy density by the beam shaping optical system 2 and enters the mask mirror 4 of the multiple reflection optical system. The laser light 21 that irradiates the opening of the mask mirror 4 travels through the opening to the imaging lens 5, but the laser light 21 that irradiates other than the opening is reflected by the dielectric thin film formed on the mask mirror 4. It goes to the total reflection mirror 3 of the multiple reflection optical system. The laser light 21 that has reached the total reflection mirror 3 is reflected by the dielectric thin film formed on the total reflection mirror 3, and travels toward the mask mirror 4 of the multiple reflection optical system. Mask mirror 4
Of the laser light 21 that has arrived at, the laser light that has radiated the opening passes through the opening toward the imaging lens 5. However, the laser light 21 radiated to the area other than the opening is reflected by the dielectric thin film formed on the mask mirror 4, and travels toward the total reflection mirror 3 of the multiple reflection optical system again. In this way, of the laser light 21 radiated to the mask mirror 4 of the multiple reflection optical system, the laser light radiated to other than the opening of the mask mirror 4 is repeatedly reflected between the mask mirror 4 and the total reflection mirror 3. You will be exercising.

The laser light 21 that has passed through the opening of the mask mirror 4 of the multiple reflection optical system travels through the imaging lens 5 to the dichroic mirror 6. The laser light 21 that has reached the dichroic mirror 6 is redirected to the processing stage 9. The laser light 21 that has reached the processing stage 9 forms an image of the pattern on the mask mirror 4 on the processing sample 11 due to the imaging action of the imaging lens 5. In this way, the pattern on the mask mirror 4 is transferred onto the processed sample 11 and the processing is completed. The state of this processing is monitored on the CRT 8 through the monitor optical system 7 arranged above the dichroic mirror 6.

In the conventional mask mirror 4 for an ultraviolet laser having a wavelength of 400 nm or less, the energy density of the laser light 21 which can be applied to the mask mirror 4 due to the absorption coefficient is below the processing threshold determined by each material. For example, in the case of Al, it is about 0.5 J / cm ² or less. On the contrary, it was difficult to apply a metal thin film material such as Al or Cr used as a usual mask material to a strong laser light such as an excimer laser light because of the problem of laser light resistance.

In particular, in a laser device having a high photon cost such as an excimer laser, it is effective to use multiple reflection of incident laser light at the mask mirror 4 in order to effectively use light. Is. In this multiple reflection optical system, the reflectivity of the mask mirror 4 has a great influence on improving the uniformity of the energy density distribution of the laser light 21 on its surface and improving the effective utilization efficiency. Therefore, the mask mirror 4 needs to have a high reflectance, which is 99%.
It is desirable to have the above. However, normal Al materials and C
For the r material, Al is about 80 to 90% and Cr is about 30 to 4
The reflectance is low at 0%, and the mask mirror 4 or the reflection mirror
It cannot be used as 3. Such an ultraviolet laser light mask mirror 4 having high laser light resistance and high reflectance characteristics is usually formed by alternately laminating a low refractive index material such as SiO2 and a high refractive index material such as HfO2. Dielectric thin film materials are used.

This dielectric thin film has, for example, a structure in which a low-refractive index material and a high-refractive index material having a film thickness of approximately λ / 4 are basically laminated in a number of tens of layers, and both the manufacturing cost and the design cost are high. It is expensive. Therefore, it is not a good idea to make one by one like a normal Al or Cr mask. Further, when this dielectric thin film is processed to be used as a mask mirror having an opening in fine processing, it is usually necessary to form it by special etching, which is more expensive.

In addition, since there is processing know-how such as what to do with the wet etching conditions for removing the dielectric thin film in the production of the mask pattern, it is difficult for a general user to create it by himself, and therefore it is usually an external manufacturer. It was often that I was asked to process it. The processing pattern relates to the know-how of the device configuration to be processed, and has been a factor that prevents the spread of the processing device from the viewpoint of preventing outflow of technical information.

[0009]

As described above, in the conventional optical processing apparatus, the dielectric thin film used as a mask mirror having an opening is very expensive and requires an opening having a complicated pattern. However, the use of a small amount is a major constraint in terms of cost, and there is processing know-how in pattern creation, and it is not easy for the user who is the purchase target of this equipment to process it easily. There was a point.

The present invention has been made to solve the above problems, and an object thereof is to obtain an optical processing apparatus capable of forming a dielectric thin film used as a mask mirror having a high reflectance by the processing apparatus itself. ..

[0011]

An optical processing apparatus according to the present invention shapes a laser beam oscillated by a laser oscillator into a predetermined shape by an opening in which a desired pattern is formed,
In an optical processing device that forms a pattern by forming an image of laser light on the surface of a workpiece as a projection image of an opening by an imaging lens, an image of the laser light is formed on the surface of the workpiece as a projection image of the opening by an imaging lens. First to form the desired pattern
It has an optical path and a second optical path which has a processing stage and forms an image of a slit, a pinhole or a desired pattern at a processing position by an imaging lens, and forms an opening pattern using the second optical path. It was done.

Further, the energy density of the laser light applied to the aperture in the first optical path is made smaller than the energy density of the laser light at the image position of the slit or the pinhole or the desired pattern in the second optical path.

[0013]

With the second optical path in the optical processing apparatus configured as described above, a desired pattern can be formed on the mask mirror made of a dielectric thin film. Since a mask of an arbitrary pattern for the multiple reflection optical system, which is the main optical system of this apparatus, can be easily created on the spot, the user does not have to worry about leakage of the pattern configuration to the outside. In addition, a large amount of expensive dielectric thin film can be formed at the same time under the same conditions, and a very large cost reduction can be achieved for each mask. In addition, a processing device having a multiple reflection optical system, which was developed for effective use of photons and was suitable for mass production but was unsuitable for small volume production,
It can be used also as a production apparatus in which a pattern frequently changes, such as high-mix low-volume production, and the versatility as a processing apparatus can be dramatically improved.

[0014]

【Example】

Example 1. FIG. 1 is a block diagram showing an optical processing apparatus according to an embodiment of the present invention. In the figure, 12 is a bend mirror, 13 is a pinhole, 14 is an imaging lens, 15 is a dichroic mirror, 16 is a monitor optical system, and 17 is a CR.
T and 18 are processing stages, 19 is a processing stage controller, and 20 is a mask mirror material as a sample.
The figure shows the case where the second optical path is formed. The laser light used in this embodiment is, for example, an ultraviolet light laser having a wavelength of 400 nm or less.

Next, the operation will be described. Where the first
The basic procedure for processing a sample by using the multiple reflection optical system using the optical path is the same as in the case of the conventional processing apparatus, and therefore is omitted here. The patterning process of the mask mirror 4 used in the multiple reflection optical system is performed by disposing the bend mirror 12 on the optical axis of the laser beam 21 and adjusting the laser beam 21 so as to pass through the pinhole 13. Oscillator 1
The laser beam 21 thus oscillated is changed in direction by the bend mirror 12 and is applied to the pinhole 13. The laser light 21 that has passed through the opening of the pinhole 13 has the imaging lens 1
After passing 4, the dichroic mirror 15 changes the direction downward so that an image of the pinhole 13 is formed on the sample 20. As the sample 20, for example, a transparent substrate such as synthetic quartz or fluorite on which a dielectric thin film is formed is placed in the processing stage 18. Sample 20
The image of the pinhole 13 formed on the sample 20 is adjusted to have an energy density higher than the processing threshold of the dielectric thin film formed on the sample 20, so that the image of the pinhole 13 is transferred to the dielectric thin film. To be done. When one image is transferred, the processing stage 18 is moved to adjust the sample position 20, and the image of the pinhole 13 is transferred to a predetermined place in the same manner. By repeating the above operation, a desired pattern can be formed on the dielectric thin film.

As described above, the processing apparatus itself can form a desired pattern on the mask mirror made of a dielectric thin film. Therefore, a mask of an arbitrary pattern for the multiple reflection optical system, which is the main optical system of this apparatus, can be easily created on the spot, and the user does not have to worry about leakage of the pattern configuration to the outside. In addition, a large amount of expensive dielectric thin film can be formed at the same time under the same conditions, and a very large cost reduction can be achieved for each mask. It was also developed for effective use of photons,
Processing equipment with multiple reflection optics, which was suitable for mass production but not suitable for small quantity production, can now also be used as a production equipment with frequent pattern changes such as high-mix low-volume production. The versatility of the processing device can be dramatically improved.

Further, since the second optical path is constructed by changing the laser optical path by the bend mirror 12, it is possible to process the dielectric thin film mask without affecting the multiple reflection optical system which requires highly accurate adjustment. Therefore, there is an effect that the adjustment of the main optical system due to the mask making becomes unnecessary.

In the first embodiment, the energy density of the laser light irradiated to the aperture in the first optical path is set to be smaller than the energy density of the laser light at the image position of the slit or the pinhole or the desired pattern in the second optical path. ing.

In the first embodiment, the image of the pinhole 13 is formed on the sample 20, but instead of the pinhole 13, a slit or one having a desired pattern is used. Even if the image is formed on the sample 20, the same effect as that of the above embodiment can be obtained.

In the first embodiment, the processing stage 18 for patterning the mask mirror is different from the processing stage 9 of the multiple reflection optical system, but these processing stages may be shared. The same effect can be obtained.

[0021]

As described above, according to the present invention, the laser light oscillated by the laser oscillator is shaped into a predetermined shape by the opening having the desired pattern, and the projected image of the opening is formed by the imaging lens. In an optical processing apparatus for forming a pattern by forming an image of laser light on the surface of a work as a first, forming a desired pattern by forming an image of the laser light on the surface of the work as a projection image of an opening by an imaging lens. It has an optical path and a second optical path which has a processing stage and forms an image of a slit, a pinhole or a desired pattern at a processing position by an imaging lens, and forms an opening pattern using the second optical path. As a result, the user of the optical processing apparatus can create a dielectric thin film mask having an arbitrary pattern, which improves the versatility of the optical processing apparatus. A.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an optical processing apparatus according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram showing a conventional optical processing device.

[Explanation of symbols]

 1 Laser Oscillator 3 Total Reflection Mirror of Multiple Reflection Optical System 4 Mask Mirror of Multiple Reflection Optical System 5 Imaging Lens 9 Processing Stage 11 Workpiece 13 Pinhole 14 Imaging Lens 18 Processing Stage 20 Mask Mirror Material 21 Laser Light

[Procedure amendment]

[Submission date] November 7, 1991

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] 0002

[Correction method] Change

[Correction content]

[0002]

2. Description of the Related Art FIG. 2 is a block diagram showing a laser processing apparatus which is an example of a conventional optical processing apparatus. This device uses, as a light source, an ultraviolet laser beam having a high photon cost, such as an excimer laser, to effectively use the photons. For this reason, a multi-reflection optical system is used, a dielectric thin film is formed as an opening having high laser light resistance and high reflectance characteristics, and the laser light transmitted through this opening is formed on the surface of the workpiece by an imaging lens. It is an apparatus for forming an image on a substrate and processing the workpiece. In the figure, 1 is a laser oscillator, 2 is a beam shaping optical system, 3 is a total reflection mirror of a multiple reflection optical system, 4 is a mask mirror of the multiple reflection optical system, 5 is an imaging lens, 6 is a dichroic mirror, and 7 is a monitor. Optical system, 8 is CRT,
9 is a processing stage, 10 is a processing stage controller,
Reference numeral 11 is a processed sample that is a workpiece, and 21 is a laser beam. The surface of the mask mirror 4 on the side of the total reflection mirror-3 is dielectric.
A body thin film is formed, and openings having a desired pattern are formed.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasuhito Nai 8-1-1 Tsukaguchihonmachi, Amagasaki City Mitsubishi Electric Corporation Production Technology Research Laboratory (72) Inventor Teruo Miyamoto 8-1-1 Tsukaguchihonmachi, Amagasaki No. Mitsubishi Electric Corporation Production Technology Laboratory (72) Inventor Masaaki Tanaka 8-1-1 Tsukaguchihonmachi, Amagasaki City Mitsubishi Electric Corporation Production Technology Laboratory

Claims (2)

[Claims] 1. A laser beam oscillated by a laser oscillator is shaped into a predetermined shape by an opening in which a desired pattern is formed, and the laser beam is projected onto the surface of a workpiece as a projected image of the opening by an imaging lens. In an optical processing device that forms an image by forming an image, a first optical path that forms a desired pattern by forming an image of the laser beam on the surface of a workpiece as a projection image of the opening by an imaging lens, and a processing stage. A second optical path for forming an image of a slit or a pinhole or a desired pattern at a processing position by an imaging lens, and forming the pattern of the opening using the second optical path. Optical processing equipment characterized by. 2. The energy density of the laser light with which the aperture is irradiated in the first optical path is smaller than the energy density of the laser light at the image position of the slit or the pinhole or the desired pattern in the second optical path. The optical processing device according to claim 1.