JPH10328859A - Optical machining device and object to be machined - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate adjustment of an optical machining device, to attain a low price of an optically machined product and to contribute to enhancement of the quality by installing, on the outside of the optical axis of coherent light at the time of machining, an optical measuring instrument for adjusting an optical device constituting the machining device. SOLUTION: A nearly coherent ultraviolet laser beam emitted from an excimer laser is directed upward by a spring mirror 5. The laser beam horizontalized by a dichroic mirror 6 is adjusted in energy with a filter 7, reflected by a dichroic mirror 13 through a shaping optical system 8, lighting lens 10 and a mask 11, and image-formed on a material 15 by an imageforming lens 14, and machining is performed according to a reduced image of the mask 11. A mirror 9 is installed on the optical axis, the laser beam is guided to an optical measuring instrument 21, thereby adjusting an optical device constituting the optical machining device. The optical measuring instrument is, for example, a device for measuring light quantity distribution, device for measuring divergent angle of coherent light, device for measuring energy of an optical pulse, spectroscope, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical processing machine for subjecting a material to physical or chemical processing and to a workpiece processed by the processing machine.

[0002]

2. Description of the Related Art Optical processing using coherent light, such as excimer laser, has a very low energy efficiency as compared with other chemical reactions and mechanical processing.
Initially, the range of use was very limited, and industrial expectations were low.

However, due to recent description innovations and social changes, requirements such as product needs, materials, optical technology, and production technology have been set, and industrial use has been flourishing, particularly in the field of fine processing.

FIG. 8 is a diagram showing an optical system used for micromachining and the like.

[0005] As shown in FIG. 8, in an optical processing machine of a system that makes extensive use of the image-forming relationship of lenses, adjustment of the optical axis of each optical element and adjustment of the focus position require high precision. Further, since the size is larger than that of a camera or the like, processing accuracy of a mechanical component such as a lens barrel cannot be obtained. Therefore, optical adjustment is very difficult.

Conventionally, such adjustment of the optical axis and the like has been performed by using a low-cost and good coherence laser such as a helium neon laser as a light source.

[0007]

However, many processing lasers such as excimer lasers have different wavelengths and modes from adjustment lasers, so that it is difficult to make fine adjustments using only the adjustment laser. In many cases, the adjustment laser cannot be used for testing the imaging performance, resulting in many test articles and defective products during processing.

[0008] Further, fine adjustment of the light amount pattern may be required due to a change in the type (setup) of the processed product, and a temperature change, a change in a laser gas, a partial deterioration of an optical component, an accident, etc. In many cases, readjustment is frequently performed.

In order to make these adjustments efficiently, it is desirable to adjust the energy and intensity distribution of the laser itself used for processing for each optical element.

[0010] However, as seen in the conventional example, the optical element and the processing jig are very compact and closely arranged, so that it is difficult to install a measuring instrument between these optical elements. In many cases, measurement at an ideal location for measurement, such as a conjugate point, is impossible.

Accordingly, the present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide an optical processing machine capable of adjusting the state of laser light for each optical element in the optical processing machine. That is.

[0012]

Means for Solving the Problems The above-mentioned problems are solved,
In order to achieve the object, an optical processing machine according to the present invention, in an optical processing machine using coherent light as a light source, adjusts an optical element constituting the optical processing machine outside an optical axis when processing the coherent light. It is characterized in that an optical measuring device for performing the measurement is installed.

Further, in the optical processing machine according to the present invention, the reference surface on which the processing optical element is installed and the reference surface on which the optical measuring instrument is installed are different surfaces, and the distance between the two reference surfaces is different. And optically coupled by optical coupling means using an optical element.

Further, in the optical processing machine according to the present invention, an optical fiber is used for the optical coupling means.

Further, in the optical working machine according to the present invention, the optical measuring device is a light quantity distribution measuring device.

Further, in the optical working machine according to the present invention, the optical measuring device is a coherent light spread angle measuring device.

Further, in the optical processing machine according to the present invention, the optical measuring device is a device for measuring energy of a light pulse.

Further, in the optical processing machine according to the present invention, the optical measuring device is a spectroscope.

Further, in the optical processing machine according to the present invention, the reference surface on which the processing optical element is provided and the reference surface on which the light source for emitting the coherent light is provided are different surfaces, and the two reference surfaces are provided. The space is characterized by being optically coupled by optical coupling means using an optical element.

[0020] Further, a workpiece according to the present invention is defined in claim 1.
9. It is characterized in that it has been processed by the optical processing machine according to any one of the above items 8 to 8.

[0021]

Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

(First Embodiment) FIG. 1 is a side view showing the structure of an optical working machine according to a first embodiment, and FIG. 2 is a plan view of FIG. 1 as viewed from above.

1 and 2, reference numeral 1 denotes an excimer laser as a light source, 2 denotes a vibration isolation table on which an all-optical system is installed, 3 denotes a table on which a processing optical system is installed, and 4 denotes an optical path cover for protecting an operator from the laser. Reference numeral 5 denotes a flip-up mirror that bends the laser light path upward, reference numeral 6 denotes a dichroic mirror that makes the light path horizontal and transmits wavelengths other than excimer laser light, and 7
Is a light amount adjusting filter, 8 is an optical system for shaping a laser pattern, 9 is a movable mirror for directing an optical path to an optical measuring instrument 21 described later, 10 is an illumination lens for forming a laser pattern on a mask, and 11 is a laser for processing a pattern. 12 is a three-axis stage that moves the mask in the vertical, horizontal and optical axis directions, 13 is a dichroic mirror that reflects only the laser wavelength downward and transmits other visible light and the like,
Reference numeral 14 denotes an imaging lens for projecting a mask image, 15 denotes a material to be processed, 16 denotes a stage having about 7 axes capable of arbitrarily adjusting the position and orientation of the material, 17 denotes a movable microscope camera, and 18 denotes an observation lens. , 19 is an observation camera, 20 is a bending mirror, 21 is an optical measuring instrument, and 22 is a helium neon laser for adjusting the optical axis.

The nearly coherent ultraviolet laser light emitted from the excimer laser 1 is reflected by the flip-up mirror 5.
The traveling direction can be directed upward. The laser light whose traveling direction is returned to the ground again by the dichroic mirror 6 is adjusted to energy suitable for processing by the filter 7,
In the shaping optical system 8, the surface distribution of the laser beam intensity is made uniform, the size is adjusted, and the spread angle is adjusted.

As a method for making the surface distribution of the laser beam intensity uniform, a method using a fly-eye lens or a method using prism division, which are well known in the past, are often used, but either of these methods may be used.

Thereafter, the mask 11 is illuminated by the illumination lens 10.
Is uniformly illuminated, and the laser beam is
In the case of drilling, it is cut into the shape of a hole. The laser light reflected by the dichroic mirror 13 and redirected downward is imaged by the imaging lens 14 on the material 15 placed at a position conjugate with the mask 11,
Processing is performed according to the reduced image of the mask 11.

In order to confirm how it was processed,
The image of the measurement object 15 is formed through the dichroic mirror 13 by the observation lens 18 designed as a pair with the imaging lens 14, and photographed by the observation camera 19.

Normally, material processing is performed in this way. However, when performing the first processing or when adjustment is necessary to correct a system that has changed over time, various optical measuring instruments can be used. , Making adjustments easier.

The main adjustment items usually required are: 1) laser energy flow rate before and after each optical element 2) uniformity of laser cross-sectional shape and intensity after each optical element emission 3) incidence of shaping optical system This is the spread angle of the laser before and after, and 4) the oscillation time shape and peak power of the laser pulse, 5) the wavelength of the laser, and 6) the energy variation between the laser pulses.

In the present embodiment, the detachable mirror 9
Is manually placed on the optical axis. At the time of adjustment, the mirror 9 is attached to a place suitable for measurement of a portion requiring measurement, and the laser is directed downward. The laser is folded again by the folding mirror 20 and the optical measuring device 21
It is led to. The mirror 9 includes a filter 7, a shaping optical system 8, an illumination lens 10, and a mask 1 according to necessary measurement items.
It is installed at an appropriate position before and after the optical element such as 1. In addition, the bending mirror 20 is moved so as to be directly below the mirror 9 according to the installation position of the mirror 9, and accordingly, the optical measuring device 21 is also moved.

By appropriately changing the optical measuring device 21 to an energy meter, an ultraviolet camera, a measuring device of another embodiment described later, or the like, the adjustments and inspections of the above 1) to 6) are performed.

The required number of measurement positions can be provided on the table 3 by making a large number of holes for passing the laser beam reflected by the mirror 9 toward the bending mirror 20.

The following effects can be raised as specific effects of this embodiment.

1) Since the flip-up mirror 5 and the dichroic mirror 6 are set to have twisted optical axes, the vertical and horizontal cross sections of the laser beam are rotated by 90 °. Normally, most excimer lasers oscillate in a pattern with a long cross section in the vertical direction, but this method rotates 90 ° and lengthens in the horizontal direction, so the height of the lens system can be reduced and a stable lens barrel shape Can be manufactured.

2) Since 6 is a dichroic mirror,
A helium neon laser 22 for roughly adjusting the optical axis can be driven coaxially with the excimer laser.

Normally, the laser for adjusting the optical axis is integrally attached to the processing laser. However, in the present embodiment, these are separate bodies, and only the processing lens can be adjusted independently. It becomes easy to determine whether the cause is on the laser side or the optical system side.

3) When the flip-up mirror 5 is removed, the height of the optical axis of the laser is located on the upper surface of the anti-vibration table 2, so that a laser experiment without using an optical system can be easily performed. For example, it can be easily used for studying laser durability of optical components and chemical changes of materials.

4) Since the movable microscope camera 17 is provided, it is possible to measure and observe a minute processing pattern which cannot be seen by the observation lens 18 without obstructing the optical path. 5) Observation Since the imaging lens 18 is designed to be paired with the imaging lens 14, the observation of the material 15 can be performed with the camera 19 without aberration by using the normal imaging lens 14 whose aberration is corrected only at the wavelength of the excimer laser. Observable with visible light.

(Second Embodiment) FIG. 3 is a side view showing a configuration of an optical working machine according to a second embodiment of the present invention.
Light is guided to an optical measuring instrument using an optical fiber.

In FIG. 3, reference numeral 201 denotes a neutral density filter, 2
Reference numeral 02 denotes an ultraviolet optical fiber bundle, and reference numeral 203 denotes an ultraviolet television camera.

At the tip of the optical fiber bundle 202 installed in the same manner as the movable mirror 9 of the first embodiment, a neutral density filter 2
The laser light attenuated at 01 enters. Optical fiber bundle 2
The laser beam transmitted inside 02 is incident on the directly-coupled ultraviolet television camera 203 while preserving its cross-sectional intensity distribution. The cross-sectional intensity distribution of the incident laser light is analyzed by an image processing device (not shown), and the operator is instructed on the cross-sectional intensity pattern.

The following effects can be raised as unique effects of the present embodiment.

1) Unlike the mirror, the optical fiber bundle has a wide allowable range of the incident direction angle. Therefore, it is possible to reduce the danger to the operator caused when the mirror is installed in an inadvertent direction.

(Third Embodiment) FIG. 4 shows a third embodiment of the present invention.
And shows an example in which the optical measuring device is a light amount distribution measuring device. The other optical system of the optical processing machine and the movable mirror 9 are the same as in the first embodiment.

In FIG. 4, reference numeral 301 denotes a one-dimensional image sensor;
302, a motor for driving the image sensor 301; 303, an image processing device; and 304, a control personal computer.

As in the first embodiment, the laser light incident on the one-dimensional image sensor 301, which is an optical measuring device, is photoelectrically converted and stored in a memory (not shown) in the image processing device 303. Since the one-dimensional image sensor cannot capture all laser patterns in one capture, it is moved by the drive motor 302 as many times as necessary to capture laser patterns sequentially.

After capturing all the laser patterns, the image processing device 303 analyzes the stored laser patterns, obtains an energy distribution, and transmits the energy distribution to the personal computer 304.

The personal computer 304 analyzes the energy distribution and instructs the excimer laser 1 to adjust the energy when the energy distribution is not suitable, or teaches the operator when the energy is out of the adjustment range.

The following effects can be raised as specific effects of this embodiment.

1) The one-dimensional image sensor can capture images wider than a normal television camera, so that it is possible to measure all patterns of the laser without providing a reduction optical system or the like.

2) Since the main body of the laser 1 usually has only the function of controlling the total energy, it cannot be examined whether or not the energy distribution per unit area, which is the most important in processing, is normal. As in the present embodiment, by controlling the laser body by measuring the energy distribution, it is possible to maintain stable processing conditions.

(Fourth Embodiment) FIG. 5 shows a fourth embodiment of the present invention.
FIG. 3 is a diagram showing the embodiment of the present invention, and shows an example in which the optical measuring instrument is a coherent light spread angle measuring device. The other optical system of the optical processing machine and the movable mirror 9 are the same as in the first embodiment.

In FIG. 5, reference numeral 401 denotes an fθ lens;
2 is an ultraviolet television camera, 403 is an image processing device, 40
Reference numeral 4 denotes a control personal computer.

As in the first embodiment, the laser beam incident on the measuring system, which is an optical measuring instrument, is Fourier-transformed by the fθ lens 401 and forms an image on the ultraviolet camera 402 with a pattern having a size proportional to the spread angle. Is done. As is well known, the spread angle θ is calculated by θ = D / f. Where f is the focal length of the fθ lens, and D is the width of the Fourier transform pattern on the camera in the direction in which the spread angle is to be obtained. The image processing device 403 obtains this value and the personal computer 404 displays it.

The following effects can be raised as unique effects of the fourth embodiment.

1) Generally, the divergence angle of a large power laser is
In many cases, it is obtained from the difference between the size of the two laser printing shapes between the vicinity of the laser emission point and the time when the laser flies sufficiently far.

This is because this method is simpler, and the divergence angle is measured to be smaller than when a Fourier transform lens is used, which is advantageous to the performance competition of laser manufacturers.

However, it is obvious that the values required for designing the illumination range and the illuminance distribution of the laser processing apparatus are closer to the values obtained by the Fourier transform lens, and the apparatus as in this embodiment is useful. is there.

(Fifth Embodiment) FIG. 6 shows a fifth embodiment of the present invention.
FIG. 3 is a diagram showing an embodiment of the present invention, and shows an example in which an optical measuring instrument is an apparatus for measuring the energy of an optical pulse. The other optical system of the optical processing machine and the movable mirror 9 are the same as in the first embodiment.

In FIG. 6, 501 is a neutral density filter, 5
Reference numeral 02 denotes an aperture plate for cutting laser light into a unit area, reference numeral 503 denotes a window with an interference film that transmits only the laser wavelength, reference numeral 504 denotes a silicon photodiode sensitized with ultraviolet rays and has a sufficiently larger area than the aperture 502, and a rise time is 1 μsec. The degree is used. Reference numeral 505 denotes a current-voltage conversion circuit with a filter, 506 denotes a peak hold circuit, 507 denotes an A / D converter, and 508 denotes a control personal computer.

As in the first embodiment, the laser beam incident on the measuring system, which is an optical measuring instrument, is applied to the neutral density filter 501.
The light amount is adjusted so as not to damage the element, and the range can be reduced to a required size by the aperture 502. Light from which a component in phase with the laser, such as fluorescence, is removed by the window 503 with the interference film enters the silicon photodiode 504. The rising frequency characteristic of the photodiode 504 is sufficiently slower than the pulse width of the laser.
The charge appearing at the output of No. 4 is proportional to the total number of incident photons. If this current is converted into a voltage by a current-voltage conversion circuit 505 with an appropriate filter, the peak value of the voltage waveform also becomes proportional to the total number of incident photons. The peak value is stored in a peak hold circuit 50.
6 and digitized by the AD conversion circuit 507 and input to the personal computer 508, so that the relative change of the light pulse can be a short time change such as between pulses or a long time such as a daily change. It becomes possible to measure.

The following points can be raised as specific effects of this embodiment.

1) Compared with a sensor using the thermoelectric effect which is generally used, the device cost is low because the sensor is an inexpensive photodiode. Even a slow photodiode can be used even if it is a pulse laser with a fast repetition because it is faster than the thermoelectric phenomenon.

2) Since the photodiode is much cheaper, more stable, and has a longer life than a commonly used photoelectric tube using the photoelectric effect, the device cost is lower. Also, instead of capturing the time waveform of the pulse like a phototube,
Since the total amount of charges is measured, a stable and simple electronic circuit can be manufactured. In the case of a pulse laser such as an ordinary processing excimer laser, the time waveform of the pulse is invariable unless a large-scale modification is performed, and it is usually impossible to measure the time waveform itself. Measuring is sufficient.

(Sixth Embodiment) FIG. 7 shows a seventh embodiment of the present invention.
FIG. 3 is a diagram showing the embodiment of the present invention, and shows an example in which an optical measuring instrument is a spectroscope for measuring the wavelength of an optical pulse. The optical system of the other optical processing machine and the optical fiber 202 are the same as in the second embodiment.

In FIG. 7, 602 is a Fabry-Perot interferometer, 603 is a cylindrical type fθ lens, 604
Is a slit for partially cutting out a spectral image, 605 is a one-dimensional PSD (position sensing device), and 606 is A
The D converter 607 is a personal computer.

As in the second embodiment, the optical fiber 20
The laser beam incident on the spectroscopic measurement system, which is an optical measuring instrument, passes through the optical fiber 202 and loses directivity at the output end of the optical fiber 202, and is then separated by the Fabry-Perot interferometer 602 into an angular distribution corresponding to the wavelength. At 603, an image is formed on the PSD 605 as a spectral image. A voltage proportional to the position of the center of gravity of the spectral image is output from the PSD 605 and the AD converter 60
6, and the wavelength is calculated by the personal computer 607. The personal computer 607 is
When the wavelength deviates from the set value, a warning is issued or a wavelength adjustment device (not shown) is instructed to correct the wavelength.

The following effects can be raised as unique effects of the present embodiment.

1) In the Fabry-Perot interference, it is necessary to scatter light efficiently and stably. In the present embodiment, however, the spread itself at the optical fiber output end is used for scattering.
A stable scattering angle can be obtained without providing an expensive fly-eye lens or scattering element.

2) Since a cylindrical lens is used for the fθ lens, and the Fabry-Perot interference image is not concentric but linear, an inexpensive one-dimensional PSD can be used instead of a two-dimensional image sensor.

3) Since a slit is provided in front of the PSD, it is possible to select and analyze any one of a plurality of interference images observed in Fabry-Perot interference.

4) Since the PSD is used for the light receiving element,
It is possible to measure the position of the center of gravity of the spectral image without performing expensive image processing.

[0073]

As described above, according to the present invention,
Since the optical measuring device can be installed off the optical axis, even if the optical elements of the optical processing machine are narrow, the necessary optical measuring device can be installed and the required optical measurement can be performed. This makes it easier to adjust the size of the optically processed product, which contributes to price reduction and quality improvement.

Further, since the energy of the optical pulse of the optical processing machine can be measured off the optical axis, the energy measuring device for the optical pulse can be installed even if the distance between the optical elements of the optical processing machine is small. Since the pulse energy can be appropriately adjusted, the adjustment of the optical processing machine is simplified.

Further, since the wavelength of light of the optical processing machine can be measured off the optical axis, even if the distance between the optical elements of the optical processing machine is small,
Since a spectroscope, which is a light wavelength measuring device, can be installed and the light wavelength can be measured appropriately, adjustment of the optical processing machine is simplified.

Further, it is possible to produce a processed product of stable quality manufactured by a stable optical processing machine.

[0077]

[Brief description of the drawings]

FIG. 1 is a side view illustrating a configuration of an optical processing machine according to a first embodiment.

FIG. 2 is a plan view of FIG. 1 as viewed from above.

FIG. 3 is a side view showing a configuration of an optical processing machine according to a second embodiment of the present invention.

FIG. 4 is a diagram showing a third embodiment of the present invention.

FIG. 5 is a diagram showing a fourth embodiment of the present invention.

FIG. 6 is a diagram showing a fifth embodiment of the present invention.

FIG. 7 is a diagram showing a seventh embodiment of the present invention.

FIG. 8 is a view showing a conventional optical processing machine.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 excimer laser 2 anti-vibration table 3 processing optical system installation table 4 optical path cover 5 flip-up mirror 6 dichroic mirror 7 light amount adjustment filter 8 shaping optical system 9 movable mirror 10 illumination lens 11 mask 12 3-axis stage 13 dichroic mirror 14 Imaging lens 15 Material to be processed 16 7-axis stage 17 Microscope camera 18 Observation lens 19 Observation camera 20 Folding mirror 21 Optical measuring device 22 Helium neon laser 201 Neutralizing filter 202 Ultraviolet optical fiber bundle 203 Ultraviolet television camera 301 One-dimensional Image sensor 302 Motor 303 Image processing device 304 Personal computer 401 fθ lens 402 Ultraviolet television camera 403 Image processing device 404 Personal computer 501 Light reduction filter 502 Aperture plate 503 With interference film Window 504 photodiode 505 current-voltage conversion circuit 506 peak hold circuit 507 AD converter 508 personal computer 602 Fabry-Perot interferometer 603 fθ lens 604 slit 605 PSD 606 AD converter 607 personal computer

Claims (9)

[Claims] 1. An optical processing machine using coherent light as a light source, wherein an optical measuring device for adjusting an optical element constituting the optical processing machine is provided outside an optical axis at the time of processing the coherent light. An optical processing machine, characterized in that: 2. A reference surface on which a processing optical element is installed and a reference surface on which the optical measuring instrument is installed are different surfaces, and an optical coupling means using an optical element is provided between the two reference surfaces. The optical processing machine according to claim 1, wherein the optical processing machine is optically coupled. 3. An optical processing machine according to claim 1, wherein an optical fiber is used for said optical coupling means. 4. The optical processing machine according to claim 1, wherein the optical measuring device is a light quantity distribution measuring device. 5. The optical processing machine according to claim 1, wherein the optical measuring device is a coherent light divergence angle measuring device. 6. The optical processing machine according to claim 1, wherein the optical measuring device is a device for measuring energy of a light pulse. 7. The optical processing machine according to claim 1, wherein the optical measuring device is a spectroscope. 8. A reference surface on which a processing optical element is installed and a reference surface on which a light source emitting coherent light is installed,
The optical processing machine according to claim 1, wherein the two reference planes are optically coupled by an optical coupling unit using an optical element. 9. A workpiece processed by the optical processing machine according to claim 1. Description: