KR100887653B1 - Scan Type Laser Processing Apparatus Having Measuring Unit - Google Patents

Abstract

Disclosed is a scan type laser processing apparatus having a function of accurately analyzing a machining process of a specimen processed by a laser beam. Disclosed is a laser processing apparatus for irradiating a laser beam to a specimen in a scan type, wherein the scattering signal generated in a plurality of regions of the specimen is selected to output only a scattering signal generated from a sample processed by an incident laser beam. An aperture, an optical splitter for changing only the path of the scattering signal provided by the aperture, an optical filter for extracting a signal of a specific wavelength band of the scattering signal provided from the optical splitter, and a specimen according to the signal extracted by the optical filter It includes a spectroscopic section for analyzing the processing information.

Laser, machining, marking, aperture, optical splitter

Description

Scan Type Laser Processing Apparatus with Measurement Units {Scan Type Laser Processing Apparatus Having Measuring Unit}

1 is a schematic block diagram showing a typical scan type laser processing apparatus;

2 is a block diagram showing a scan type laser processing apparatus having a measurement unit according to an embodiment of the present invention;

3 is a block diagram showing a scan type laser processing apparatus having a measurement unit according to another embodiment of the present invention;

4 is a block diagram showing a scan type laser processing apparatus having a measurement unit according to another embodiment of the present invention;

5 is a block diagram showing a scan type laser processing apparatus having a measurement unit according to another embodiment of the present invention; and

6 is a view for explaining a scattering signal selection process by the aperture according to an embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

120: scanner 130: lens

140: specimen support 150: specimen

160: aperture 170, 250: optical splitter

200: measurement unit 220, 260: optical filter

230,270: Spectroscope

The present invention relates to a laser processing apparatus, and more particularly, to a scan type laser processing apparatus for irradiating a laser beam by a scanner method.

In general, the processing of materials using a laser is rapidly expanding the field of application throughout the industry. In particular, laser processing is very good in terms of precision, process flexibility, non-contact processing and minimal heat effects, so it is widely used in marking, heat treatment, welding and drilling processes.

Among them, laser marking is a technique of marking a desired character or figure by discoloring by melting and etching part of the surface of an object using a laser beam as a light source. This laser marking is a non-contact, permanent marking, and can be clearly marked with high accuracy because the laser beam is used as a direct processing means, compared to the marking method using a conventional inkjet printer or silk printing.

A typical marking device may consist of a laser light source, a lens and a specimen support. The laser light source irradiates the laser beam toward the specimen, and the lens focuses the beam provided from the laser light source onto the specimen. In addition, the marking apparatus may further include a measurement unit on one side of the lens. The measurement unit measures the optical signal emitted from the specimen and detects the machining state of the specimen. The measurement unit can increase the accuracy of machining and the stability of the machining process. Conventionally, the focus of laser light and the optical signal emitted from the specimen are collected by a confocal optical system.

On the other hand, since ultra-precision machining of a micro structure is required, a higher processing speed is calculated | required. Accordingly, a method of irradiating the laser beam in a scan type has been proposed in a state in which a specimen (a specimen support) is fixed.

As shown in FIG. 1, the scan type laser marking device includes a light source 10, a scanner 20, a lens 30, and a specimen support 40.

The path of the laser beam L1 irradiated from the light source 10 is changed by the scanner 20, and the lens 30 focuses the laser beam L1 moving two-dimensionally by the scanner 20. The lens 30 uses an f-thata lens whose focal length does not change with respect to a change in the incident angle.

 As described above, in the scan type laser marking apparatus using the f-theta lens, the laser beam is irradiated onto the specimen by the scanner 20 to enable high-speed marking.

The scan type laser marking device also requires a measurement unit to detect the machining state of the specimen. However, in the scan type laser marking apparatus, as the laser beam is moved by the high speed scanner, the position where the laser beam is focused on the specimen changes rapidly. Therefore, analysis of the specimen 45 by the confocal optics used in the fixed laser marking apparatus is virtually impossible.

Specifically, in the case of a fixed laser marking apparatus, when a laser beam is injected into a fixed path and reaches a specimen, the F-theta lens collects optical signals scattered from a specific portion of the specimen to provide confocal optics. Provided.

However, in the case of the scan type laser marking apparatus, since the laser beam is moved by the scanner, the position of the laser beam reaching the specimen is changed. As a result, the scattering signal collection efficiency is changed by the f-theta lens.

In this way, when the position where the laser beam is focused on the sample is changed by changing the path of the laser beam by the scanner, the following problems may occur optically.

First, the collection angle of the scattering signal generated on the sample surface and incident and collected by the ftheta lens is changed, and thus the collection efficiency of the scattering signal by the ftheta lens is changed.

In addition, since the signal generated by the fexeta lens contains not only the wavelength of the laser beam but also light of various other wavelengths, when the conventional confocal optical system is used, the collection efficiency of the scattering signal is changed according to the wavelength.

In addition, the F-theta lens is generally designed to match the wavelength of the laser light to be used. As a result, various kinds of optical aberrations are generated for the spectroscopic signals having various wavelengths. For this reason, in order to collect scattering signals generated from samples at different positions at one point, an F-theta lens with corrected chromatic aberration is required. However, designing and manufacturing an F-theta lens that corrects chromatic aberrations at various wavelengths required for laser process measurement is in fact very difficult, and especially expensive to produce. That is, when using a spatial filter with a small opening such as a confocal optical system using a spatial filter having a small opening, a problem arises in that the measurement efficiency of the signal varies depending on the processing position. .

Accordingly, the optical signal (scattering signal) obtained by using the f-theta lens cannot be the processing information of the specific portion of the specimen 45. Therefore, in the case of a scanner type laser processing apparatus, accurate specimen analysis cannot be performed.

Accordingly, an object of the present invention is to provide a scan type laser processing apparatus capable of accurately analyzing the processing result of a specimen processed by a laser beam.

Laser processing apparatus of the present invention for achieving the above object of the present invention, a light source for irradiating a laser beam, a scanner for changing the traveling direction and the incidence angle of the laser beam, focusing the laser beam provided from the scanner to the specimen A first lens, a plurality of scattering signals emitted from a plurality of regions of the specimen, an aperture for selecting a scattering signal corresponding to the incident laser beam, and a measurement for measuring processing information of the specimen by the scattering signal It includes a unit.

In addition, according to another embodiment of the present invention, a laser processing apparatus for irradiating a laser beam to the specimen in a scan type, and only the scattering signal corresponding to the incident laser beam of the scattering signal generated in a plurality of areas of the specimen is selected and outputted An optical splitter for changing only a path of a scattering signal provided by the aperture, an optical filter for extracting a signal of a specific wavelength band of the scattering signal provided by the optical splitter, and a signal extracted by the optical filter. And a spectroscopic section for analyzing the processing information of the specimen.

Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings.

The present invention will disclose a scan type laser processing apparatus having a measurement unit. The metrology unit will detect the scattering signal fed back from the specimen and analyze the processing state of the specimen. At this time, as the laser irradiation is made of a scan type, in order to measure scattering signals generated at different positions of the specimen, an aperture for uniformly adjusting the collection angle of the scattering signal is installed in the path between the measurement unit and the specimen. By installing an optical splitter for transmitting the scattered signal picked up from the aperture to the metrology unit, it will be possible to accurately measure the laser processing information of the specific region of the specimen.

The scan type laser processing apparatus as described above will be described in more detail.

2, the scan type laser processing apparatus 100 according to the present embodiment includes a laser light source 110, a scanner 120, a lens 130, a specimen support 140, an aperture 160, and a light splitter. (splitter) 170 and measurement unit 200.

The scanner 120 changes the traveling path and angle of the laser beam emitted from the light source 110. That is, the scanner 120 changes the irradiation position of the laser beam so that the laser beam can sequentially reach each part of the specimen 150.

The lens 130 focuses the laser beam provided from the scanner 120 on the specimen 150 placed on the specimen support 140. As the lens 130, an f-theta lens having a constant focal length is used regardless of the magnitude of the incident angle of the laser beam.

The aperture 160 uses the scanner 120 to prevent the signal collection efficiency from varying according to the generation position of the scattering signal emitted from the specimen 150. The laser traveling direction (direction of the incident laser beam) is performed. On the contrary, it plays a role of making the collection angle of the scattering signal progressing constant. That is, the aperture 160 is a scattering signal (scattering corresponding to the direction of the incident laser beam) of the plurality of scattering signals (S1, S2, S3 ...) fed back as opposed to the direction of the incident laser beam Signal).

The light splitter 170 transmits only the scattering signal to the measurement unit 200. That is, the scattering signal and the laser beam may be incident on the light splitter 170 at the same time. In this case, the light splitter 170 changes the path of the scattering signal so that the scattering signal reaches the measurement unit 200 and transmits the laser beam as it is.

The measurement unit 200 analyzes the scattering signal received from the light splitter 170 to predict the processing information of the specimen 150. The measurement unit 200 includes a second lens 210, an optical filter 220, and a spectroscope 230.

The second lens 210 focuses the scattering signal provided from the light splitter 170. In this case, as shown in FIG. 3, an additional aperture 215 (hereinafter, referred to as a second aperture) may be further installed in the second lens 210 to make the collection angle of the scattering signal constant.

The optical filter 220 extracts only a signal necessary for process measurement, that is, an optical signal having a specific wavelength, from the scattering signals provided from the second lens 210. In this case, the lenses 130 and 210 are designed in consideration of the wavelength of the laser beam. However, in order to collect scattering signals S1, S2, S3 .. of a wavelength different from that of the laser beam used to process the specimen 150, the lenses 130 and 210 according to the present exemplary embodiment require chromatic aberration correction. need. When the scattering signal is analyzed in the state where such chromatic aberration correction is not performed, the signal measurement efficiency changes according to the processing position. In order to solve this problem, a large cost is required when constructing an optical system using an F-theta lens that corrects chromatic aberration. However, in the present embodiment, by providing the optical filter 220 in the measurement unit 200, it is possible to detect scattered signals having various wavelengths with a constant collection efficiency without correcting chromatic aberration of the lens.

On the other hand, the specimen 150 may be a heterogeneous compound or heterojunction material, in this case, processing information is required for each material. In this case, scattering signals having different wavelengths must be measured simultaneously. When scattering signals having different wavelengths are to be measured at the same time, as shown in FIG. 4, the second light splitter 250, the second optical filter 260, and the second spectroscope are included in the measurement unit 200. 270 may be additionally installed. The second optical splitter 250 includes a scattering signal focused by the second lens 210, a scattering signal having a first wavelength (S1-1, hereinafter, a first scattering signal) and a scattering signal having a second wavelength ( S1-1, hereinafter, the second scattering signal), and the first scattering signal S1-1 is transmitted to the first spectrometer 230 through the first optical filter 220, thereby Process measurement of the first component is performed, and the second scattering signal S1-1 is transmitted to the second spectroscope 270 through the second optical filter 260 to provide the second component of the specimen 150. Process instrumentation is made. In this case, the second optical filter 260 plays the same role as the first optical filter 220, and the second spectroscope 270 plays the same role as the first spectroscope 230.

The spectroscope 230 receives the optical signal provided from the optical filter 220 to predict the laser processing result (information) of the specimen 150. As the spectroscope 230, a spectrometer capable of measuring a spectral distribution by an optical signal may be used. Scattering signal transmission from the specimen 150 to the measurement unit 200 may be transmitted by the optical fiber 300, such optical fiber 300 is shown in Figure 5 to improve the signal collection efficiency due to aberration It may be configured in a bundle (bundle) as shown. 5, 310 shows a bundle type optical fiber. In this case, the single or bundle type optical fibers 300 and 310 preferably have a diameter of 1 to 2 mm in the light receiving portion so as to further improve signal collection efficiency due to aberration. The portion coupled to the 230 and 270 may be manufactured to have a thickness of 10 to 100 μm vertically to increase the resolution of the spectroscopic portions 230 and 270.

The operation of the scan type laser processing apparatus 100 of this embodiment is as follows.

When the laser beam L1 is irradiated from the light source 110, it passes through the light splitter 170 and the aperture 160 to reach the scanner 120, and the path of the laser beam L1 is driven by the scanner 120. Is changed.

The laser beam L1 provided in the scan type is focused on the lens 130 and irradiated to a plurality of regions of the specimen 150. In the specimen 150 to which the laser beam L1 is irradiated, a plasma is generated as shown in FIG. 2, and a scattering signal is generated at the generated portion of the plasma. At this time, as the laser beam (L1) is irradiated while moving by the scanner 120, the scattering signal is generated in a plurality of areas of the specimen 150.

The scattering signals generated in the plurality of regions are fed back through the lens 130 and the scanner 120 which are incident paths of the laser beam L1. At this time, the plurality of scattering signals (S1-SN) having information of a plurality of regions of the specimen 150, while passing through the aperture 160, as shown in Figure 6, corresponds to the incident laser beam (L1) The scattering signal S1 is selected.

The selected scattering signal S1 is transmitted to the measurement unit 200 by the light splitter 170. The scattering signal S1 is focused again by the lens 210 in the measurement unit 200 and / or by the aperture 220 in the lens 210, and only the scattering signal having a noise and a specific wavelength by the optical filters 220 and 260. After extraction, the spectroscopes 230 and 270 analyze the laser processing result of the specific region of the specimen.

The present invention is not limited to the above embodiment.

In the present embodiment, for example, one or two optical filters and spectroscopic sections are provided in the measurement unit 200. For example, a plurality of optical filters and spectroscopic sections may be provided in consideration of the components of the specimen.

In addition, in the present embodiment, a laser marking apparatus has been described as an example, but is not limited thereto. The laser marking apparatus may be applied to all laser processing apparatuses for processing a specimen using a laser.

Although the present invention has been described in detail with reference to preferred embodiments, the present invention is not limited to the above embodiments, and various modifications may be made by those skilled in the art within the scope of the technical idea of the present invention. Do.

As described in detail above, according to the present invention, only the aperture and the scattering signal for measuring scattering signals generated at different positions by the laser beam of the laser processing apparatus irradiated with the laser beam in a scan type with a constant collection efficiency An optical splitter to transmit to the measurement unit for measuring the processing state of the sensor.

As a result, accurate scattering signals for specific regions can be detected, analysis can be performed, and accurate laser processing results can be detected.

Claims (10)

A light source for irradiating a laser beam; A scanner for changing the advancing direction and the incident angle of the laser beam; A first lens focusing the laser beam provided from the scanner onto a specimen; An aperture receiving a plurality of scattering signals emitted from a plurality of regions of the specimen and selecting scattering signals corresponding to the incident laser beams; And And a measurement unit for measuring machining information of the specimen by the scattering signal. The method of claim 1, And a light splitter for transmitting only the scattering signal to the measurement unit between the aperture and the measurement unit. The method of claim 1, The measurement unit, A second lens focusing the scattering signal; An optical filter for extracting a specific wavelength of the scattering signal focused by the second lens; And And a spectroscope configured to analyze processing information of a specific region of the specimen by the scattering signal from which the specific wavelength is extracted. The method of claim 3, wherein When the specimen is a heterogeneous compound, it is necessary to extract a scattering signal having a plurality of specific wavelengths, A second optical splitter for further dividing a scattering signal focused from the second lens; A second optical filter for extracting scattered signals separated by the second optical splitter; And And a spectroscope configured to analyze the scattering signal provided from the second optical filter. The method of claim 3, wherein And a second aperture in the second lens. The method of claim 1, And an optical fiber for transmitting the laser beam and the scattering signal. The method of claim 6, The light receiving portion of the optical fiber has a diameter of 1 to 2mm. The method of claim 7, wherein The optical fiber is a laser processing device having a bundle form. A laser processing apparatus for irradiating a laser beam to a specimen in a scan type, An aperture for selecting and outputting only a scattering signal corresponding to an incident laser beam among scattering signals generated in a plurality of regions of the specimen; An optical splitter for changing only a path of a scattering signal provided at the aperture; And An optical filter for extracting a signal of a specific wavelength band of the scattering signal provided from the light splitter; And Laser processing apparatus comprising a spectroscopic portion for analyzing the processing information of the specimen in accordance with the signal extracted by the optical filter. The method of claim 9, The spectroscopic portion is a laser processing apparatus (spectrometer).

Images