JPH10249569A - Laser beam machining device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To uniformize the distribution of laser beam intensity between optical transmission bodies, in a laser beam machining device using optical transmission bodies, to detect the laser beam after the transmission through the optical transmission bodies, and to control the light intensity at a constant level after the transmission. SOLUTION: A laser beam from a laser beam generator 1 is uniformized by a uniformizing optical system 2, and then introduced to the bundle 4 of optical transmission bodies. In the bundle 4, the light intensity of the plural transmission bodies 11 for detection is detected by a photodetector 14 and compared, thereby uniformizing the optical intensity of the outgoing beam 7 from the transmission bodies 5 for machining, and also enabling the detection of the laser beam after the transmission through the optical transmission bodies. In addition, on the basis of the output signal of the photodetector 14, the laser generator 1 is feedback-controlled using a machining control device, which enables the light intensity to be controlled at a constant level after the transmission through the optical transmission bodies.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser processing apparatus for irradiating a workpiece with a laser beam from a laser oscillator through an optical transmission unit and a reduction imaging optical system.

[0002]

2. Description of the Related Art Conventionally, many processing apparatuses using laser light have been proposed. For the most part, most of the processing apparatuses have a combination of a mask and a reduced projection optical system.
This is a processing method in which a laser beam is irradiated on a mask, and the laser beam transmitted through the opening of the mask is reduced and projected using a lens system to irradiate a workpiece. In this method, most of the laser light is reflected by the mask, the intensity of the laser light used for actual processing is only about 1 to 2% before the incidence on the mask, and the laser light use efficiency is extremely low. .

[0003] In order to improve the light use efficiency, a laser processing apparatus using a plurality of optical transmission bodies has been developed. As a laser processing apparatus using such a plurality of optical transmission bodies, there is a multi-axis beam laser processing machine described in JP-A-6-55288 shown in FIG.

Hereinafter, a conventional laser beam machine will be described. In FIG. 7, reference numeral 101 denotes a laser oscillator which emits laser light. Reference numeral 102 denotes a processing light transmitting body through which laser light can pass, and the laser light incident side is collectively formed as an introduction end 102a. As shown in FIG. 8, the introduction end 102a is obtained by solidifying the ends of a plurality of optical transmitters 111 with a filler 113 in a transmitter folder 112.
The range indicated by the chain line is the laser beam irradiation area 114. The laser light propagates through the processing light transmission body 102 from the introduction end 102a and is emitted from the processing emission end 102b. This light is reduced by the reduction imaging optical system 103,
The workpiece 104 fixed to the sample mounting table 105 is irradiated and processed. In order to keep the processing conditions constant, it is necessary to make the laser light output from each of the processing light transmitting bodies 102 equal, and the apparatus is installed and installed with sufficient adjustment.

In order to keep the laser beam intensity constant,
The laser oscillator 101 has a mechanism for keeping the laser output constant. Specifically, a part of the laser light is split by a partial reflecting mirror, the light intensity of the reflected light is measured, the laser light intensity is detected, and the laser output is controlled to be constant based on the detection signal ( Feedback control). This makes it possible to keep the laser light intensity immediately after emission from the laser oscillator 101 constant.

[0006]

SUMMARY OF THE INVENTION The above-mentioned Japanese Patent Laid-Open No. 6-5 / 1994
In the multi-axis beam laser processing machine described in Japanese Patent No. 5288, in order to equalize the processing quality between the respective beams, it is necessary to equalize the intensity of the emitted laser light between the respective optical transmission bodies. After making the in-plane intensity distribution uniform, a laser beam is incident on each optical transmission body. However, in the laser beam machine, even if the angle of incidence of the laser beam on the bundle of optical transmitters is slightly changed, the intensity of the laser beam between the optical transmitters differs. Since the incident angle of the laser beam changes when there is a time-dependent positional shift of various optical elements or a change in the optical axis during laser maintenance, the intensity of the emitted laser beam between the transmitters varies. Will be.

[0007] In the configuration shown in FIG. 7, the variation of the light intensity among the respective optical transmission bodies is determined by measuring the light intensity of all the emitted light.
Although there was no other way but to compare, it is often difficult to measure the light intensity of all the emitted light due to the configuration of the device, and it was confirmed that the intensity of the emitted laser light between each transmitter was almost constant. There was also a problem that there was no means to confirm.

Further, it is necessary to optimize the processing conditions by changing the laser output to be irradiated according to the workpiece.
In the configuration of the multi-axis beam laser beam machine shown in FIG. 7, the laser beam intensity before entering the optical transmitter can be detected, but the laser beam intensity after passing through the optical transmitter cannot be detected. . The processing condition required for laser processing is the intensity of laser light for irradiating the workpiece. Since the processing optical system is deteriorated or changes with time, even if the laser light intensity incident on the processing optical system is constant, the laser light intensity for irradiating the workpiece is not always constant. Conventional laser light intensity adjustment can only be performed by branching a part of the light emitted from the laser oscillator and detecting the light intensity. With this method, the entire laser light intensity before entering the processing optical system can be detected. However, there is a problem that the light intensity after transmitting through the optical transmitter cannot be measured.

The present invention solves the above problems,
A second object of the present invention is to provide a laser processing apparatus capable of making the light intensity distribution between optical transmission bodies uniform, and to provide a laser processing apparatus capable of detecting laser light transmitted through the optical transmission body. It is a third object of the present invention to provide a laser processing apparatus capable of controlling light intensity after passing through an optical transmission body to be constant.

[0010]

In order to achieve the first object, the present invention provides a method of manufacturing a plurality of optical transmission members, which are not subjected to processing, when a bundle of optical transmission members is irradiated with a laser beam. Make it possible to compare the output laser light intensity of the transmitter with each other,
If the emitted laser light intensity is equal within the allowable error range,
The intensity of the laser beam emitted from the all-optical transmission medium can be estimated to be equal. Thereby, it is possible to confirm that the intensity of the laser light emitted from each optical transmission body is substantially uniform without breaking the configuration of the processing device. Further, adjustment for equalizing the intensity of laser light emitted from each optical transmission body can be performed.

In order to achieve the second object,
The present invention monitors laser light emitted from a light transmitting body that is not subjected to processing when the light transmitting body bundle is irradiated with laser light, thereby detecting laser light intensity, detecting the number of laser light pulses, and cumulative irradiation pulses. It is configured to detect at least one of energy detection, laser light pulse time detection, and laser light wavelength detection. This makes it possible to detect the laser beam after passing through the optical transmission body.

Further, in order to achieve the third object,
The present invention monitors a laser beam emitted from an optical transmitter not subjected to processing, receives a photodetector and an output signal from the photodetector, and includes a processing control device that issues a control signal that changes an oscillation state of a laser oscillator. It is configured to be controllable. Thus, the light intensity after passing through the optical transmission body can be controlled to be constant, not the laser oscillator emission port.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention is directed to a laser oscillator for emitting a laser beam, a homogenizing optical system for equalizing the intensity distribution of the laser beam emitted from the laser oscillator, The light transmitting body bundle in which the input ends of the plurality of light transmitting bodies for transmitting the uniformized laser beam are bundled, and the respective light emitting ends are bundled so as to be separable, and the light transmitting body bundle is provided at least for processing. It is composed of both a transmitting body for processing and a transmitting body for detection provided for light detection,
What is claimed is: 1. A laser processing apparatus comprising a photodetector for detecting a laser beam emitted from an emission end face of said detection transmission body, wherein said processing transmission body is provided for processing and said detection transmission body is provided for light detection. By detecting only the light emitted from the detecting transmitter, there is an effect that it is not necessary to measure the light emitted from all the optical transmitters.

According to a second aspect of the present invention, there is provided at least two or more detection transmitters, and the light intensity of the light detection output laser light emitted from the output end face of the detection transmitter is controlled. 2. The laser processing apparatus according to claim 1, wherein each of the detection transmitters is detected and compared with each other, and the position and inclination of the optical transmitter bundle are compared by comparing the laser beam intensity from the detection transmitter. Has an effect that the output between the optical transmitters can be made uniform.

According to a third aspect of the present invention, there is provided a laser processing apparatus according to the first or second aspect, further comprising a processing control device for controlling a laser oscillator using a detection signal from a photodetector. By the processing control device controlling the laser oscillator based on the detection signal from the detector, it is possible to obtain a laser beam suitable for laser processing.

According to a fourth aspect of the present invention, the light detector detects the laser light intensity, detects the number of laser light pulses,
4. The laser processing apparatus according to claim 3, wherein the laser processing apparatus has at least one of a detection function of detecting a total irradiation pulse energy, a laser light pulse time, and a laser light wavelength. , Number of laser light pulses, total irradiation pulse energy, laser light pulse time,
This has the function of detecting at least one of the wavelengths of the laser light.

According to a fifth aspect of the present invention, the processing control device performs feedback control of the laser oscillator using the detection signal from the photodetector so that the laser beam intensity after passing through the optical transmitter becomes constant. The laser processing apparatus according to claim 4, wherein the laser beam transmitted through the optical transmitter is detected by a photodetector, and the laser beam transmitted through the optical transmitter based on a detection signal from the photodetector. There is an effect that the processing control device can perform feedback control of the laser oscillator so that the laser light intensity becomes constant.

FIG. 1 shows an embodiment of the present invention.
This will be described with reference to FIG. (Embodiment 1) FIG. 1 shows a configuration of a laser processing apparatus according to a first embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a laser oscillator that emits laser light, and 2 denotes a homogenizing optical system that makes the intensity distribution on a plane perpendicular to the optical axis of the laser light from the laser oscillator 1 uniform. Is obtained, and a uniformed laser beam 3 is obtained. Reference numeral 4 denotes a light transmitting body bundle in which a plurality of light transmitting bodies are bundled at the incident end 4a, and includes a processing transmitting body 5 and a detecting transmitting body 11. The emission end 5 a of the processing transmission body is held by the emission end holding plate 6. Reference numeral 7 denotes an output beam for processing emitted from the transmission body for processing 5.
The upper workpiece 9 is irradiated. Reference numeral 11 denotes a detection transmission body branched from the input end 4a of the optical transmission body bundle 4 to the processing transmission body 5, and the emission end 11a is held by the emission end holding plate 12. Reference numeral 13 denotes a detection emission beam emitted from the detection transmission body 11, and is incident on the photodetector 14.

FIG. 2 shows the intensity distribution of a uniformed laser beam in the present embodiment. In the present embodiment, the laser light is shaped into a rectangle. An XY plane formed by the X axis and the Y axis is a plane perpendicular to the propagation direction of the laser light, and the Z axis indicates the intensity of the laser light. It can be seen that the laser beam is shaped into a rectangle and the in-plane intensity after the shaping is almost uniform. This homogenized laser beam 3 is applied to the optical transmitter.

FIG. 3 shows the configuration of the optical transmission body bundle according to the present embodiment. In FIG. 3, reference numeral 24 denotes a plurality of optical transmission bodies, which can transmit laser light without attenuating the laser light intensity. In this embodiment, an optical fiber made of quartz is used. One end of each of the plurality of transmitters 24 is fixed in position by the filler 22, and constitutes a laser beam irradiation area 23 as a whole.
0 for easy handling. Transmission body 2
4 is optically polished, and when the homogenized laser beam 3 is irradiated into the laser beam irradiation area 23,
The laser light propagates in the transmission body 24 and exits from the emission end 25 to the outside. On the emission end 25 side, the transmission bodies 24 have a structure that can be individually separated one by one, and are separated into the processing transmission body 5 and the detection transmission body 11 described above.

FIG. 4 shows the configuration of the leading end of the optical transmission member bundle in the present embodiment. Laser beam irradiation area 23
The processing introduction end 28 of the processing transmission body 5, the detection introduction end 27 of the light detection transmission body 11, and the unused introduction end 26 of the disposed transmission body that is not used. End faces of different types of transmission bodies are arranged. Since each transmitter is disposed in the laser beam irradiation area 23, the intensity of the laser beam propagating in each transmitter is the same. In the present embodiment, the detection introduction ends 27 are set at the four corners where the optical transmitter is arranged. The uniformizing laser beam 3 is irradiated to the introduction end 21 of the optical transmission body bundle configured as described above.

The processing emission beam 7 emitted from the processing emission end 5a is condensed by the reduction imaging optical system 8 on the optical axis, and irradiates the workpiece 9 on the sample mounting table 10. In this embodiment, a XeCl excimer laser oscillator (wavelength 308 nm) is used as the laser oscillator 1. In addition, a polyimide film is used for the workpiece 9. The processing output beam 7 is condensed on the workpiece 9 and the energy density thereof is adjusted to be 1 J / cm ² . Under these conditions, the polyimide film to be processed 9 is made of XeCl
It has been confirmed that a hole of about 0.5 μm in the depth direction can be formed every time one pulse of the excimer laser is irradiated. When the thickness of the polyimide film to be processed 9 is 150 μm, the through hole can be processed by irradiating 300 pulses of XeCl excimer laser light.

When the intensity of the processing output beam 7 is different due to an optical axis shift or replacement of the laser oscillator, the adjustment is performed by changing the position and inclination of the introduction end 4a. At this time, the position and inclination of the introduction end 4a are adjusted in order to make the light intensity of the detection output beam 13 emitted from the detection transmitter 11 arranged at the four corners equal. Output beam 1 for detection
The light intensity of No. 3 is detected by the light detector 14, and the light intensity can be known. Since the light intensity distribution in the laser beam irradiation area 23 is gradually changing, the detection transmitters 11 arranged at the four corners in the laser beam irradiation area 23
By making the light intensities of the detection outgoing beams 13, which are the outgoing lights from the optical transmitters, equal, the light intensities propagating through all the optical transmitters become equal.

As described above, according to the first embodiment, the light intensity of the processing output beam 7 is measured without measuring the light intensity of the processing output beam 7 emitted from all the processing output ends 5a. It can be adjusted to be uniform.

In the first embodiment, the two photodetection output beams 13 are simultaneously measured by the photodetector 14, but the measurement may be performed for each beam.

(Embodiment 2) FIG. 5 shows the configuration of a laser processing apparatus according to a second embodiment of the present invention.
A processing controller 15 is connected between the photodetector 14 and the laser oscillator 1 in the first embodiment shown in FIG. Otherwise, the configuration is the same as that shown in FIG. 1 except that the number of the transmission body 11 for detection is one, so that the same components are denoted by the same reference numerals, and redundant description will be omitted.

FIG. 6 shows the configuration of the introduction end of the optical transmission body bundle in the present embodiment, which is different from the first embodiment shown in FIG. End 2
7 is provided in one place, and the other configuration is the first
This is the same as the embodiment.

The light intensity of the output beam 13 for detection, which is the output light from the transmitter 11 for detection, is detected by the photodetector 14. The processing control device 15 captures this detection signal,
Perform a comparison operation with the reference value. Thereafter, a control signal is sent from the processing control device 15 to the laser oscillator 1, and the laser oscillator 1
Changes the oscillation state based on the control signal to change the intensity of the emitted laser light. As described above, by performing the feedback control, the light intensity of the processing output beam 7 can be controlled to a set value.

In this embodiment, the photodetector 1
The laser beam 4 is used for converting the laser beam intensity into an electric signal and detecting the laser beam intensity, but may be used for detecting the laser beam and measuring the number of pulses. Furthermore, it may be used for the purpose of detecting a laser beam and generating a synchronization signal of another measuring instrument. Further, the laser beam intensity and the number of pulses may be detected to serve the purpose of detecting the total irradiation energy amount. Further, it goes without saying that the present invention may be used for detecting the wavelength of laser light, detecting the emission time of laser light, and the like.

In the present embodiment, the detecting transmitter 1
Although only one is used, it goes without saying that two or more may be used at the same time. At this time, it does not matter if the individual transmission bodies are used for different purposes. Further, in the present embodiment, the feedback control is performed using the detection signal from the photodetector 14, but it may be provided for the purpose of displaying and transmitting the detection signal to the outside.

[0031]

As described above, according to the present invention, it is possible to provide a laser processing apparatus capable of maintaining a constant light intensity distribution between optical transmitters, and to detect a laser beam transmitted through the optical transmitter. And a laser processing apparatus capable of controlling the laser beam after passing through the optical transmission body at a constant level can be provided.

[Brief description of the drawings]

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

FIG. 2 is an in-plane intensity distribution diagram of a uniformed laser beam according to the first embodiment of the present invention.

FIG. 3 is a perspective view of a light transmission body bundle according to the first embodiment of the present invention.

FIG. 4 is an enlarged front view of an incident surface of the optical transmission body bundle according to the first embodiment of the present invention.

FIG. 5 is a configuration diagram of a laser processing apparatus according to a second embodiment of the present invention.

FIG. 6 is an enlarged front view of an incident surface of an optical transmission body bundle according to a second embodiment of the present invention.

FIG. 7 is a configuration diagram of a laser processing apparatus in a conventional example.

FIG. 8 is an enlarged front view of an incident surface of an optical transmission body bundle in a conventional example.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 laser oscillator 2 homogenizing optical system 3 homogenizing laser beam 4 optical transmission body bundle 5 processing transmission body 6 emission end holding plate 7 processing emission beam 8 reduction imaging optical system 9 workpiece 10 sample mounting table 11 detection Transmitter 12 Emission end holding plate 13 Outgoing beam for detection 14 Photodetector 15 Processing controller 20 Transmitter folder 21 Introducing end 22 Filler 23 Laser beam irradiation area 24 Optical transmitting body 25 Emitting end 26 Unused introducing end 27 For detection Inlet 28 Inlet for machining

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yuji Tate Tachikawa-san, Kawasaki City, Kanagawa Prefecture 3-10-1 Higashi Mita Inside Matsushita Giken Co., Ltd. (72) Inventor Nobuyasu Suzuki Tama-ku, Kawasaki City, Kanagawa Prefecture Matsushita Giken Co., Ltd. 3-10-1 Higashi-Mita

Claims (5)

[Claims] 1. A laser oscillator for emitting a laser beam, a uniforming optical system for equalizing an intensity distribution of the laser beam emitted from the laser oscillator, and a plurality of lasers for transmitting the uniformed laser beam. An optical transmitter bundle in which the incident ends of the optical transmitters are bundled, and the respective output ends are bundled so as to be separable, and the optical transmitter bundle is provided at least for a processing transmitter and a light detector for processing. A laser processing apparatus, comprising: a transmission body for detection; and a photodetector that detects a laser beam emitted from an emission end face of the transmission body for detection. 2. The method according to claim 1, further comprising at least two or more detection transmitters, and detecting the light intensity of the laser beam emitted from the emission end face of the detection transmitter for each detection transmitter. The laser processing apparatus according to claim 1, wherein the comparison is made with: 3. The laser processing apparatus according to claim 1, further comprising a processing control device that controls a laser oscillator using a detection signal from the photodetector. 4. The photodetector detects at least one of laser light intensity detection, laser light pulse number detection, cumulative irradiation pulse energy detection, laser light pulse time detection, and laser light wavelength detection. The laser processing apparatus according to claim 3, having a function. 5. The processing control device performs feedback control of a laser oscillator using a detection signal from a photodetector so that a laser beam intensity after passing through an optical transmission body becomes constant. Laser processing equipment.