JP2008279470A - Calibration method of laser beam machining apparatus, and laser beam machining apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a calibration method of a laser beam machining apparatus capable of calibrating a laser beam machining apparatus without forming any machining trace on a workpiece with high accuracy, and the laser beam machining apparatus. <P>SOLUTION: The calibration method comprises a step of radiating guide beam G to at least three different positions on a workpiece 16 by changing the input at the beam radiation designation position on a control mechanism of an optical scanning means, a step of acquiring the state of radiation of the guide beam G as an image by a camera for observation provided immediately above the workpiece 16 every time when the guide beam is radiated on the workpiece, a step of measuring the guide beam radiation center position in the image by the image processing, and a step of statistically obtaining the conversion coefficient for calibrating the optical scanning means from the beam radiation designation position input in the control mechanism and the guide beam radiation center position measured from the image corresponding to the beam radiation designation position. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a laser processing apparatus calibration method and a laser processing apparatus, and more particularly to defects in device patterns and wiring patterns formed on a processing object such as a TFT substrate used in flat panel displays such as liquid crystal and organic EL. The present invention relates to a laser processing apparatus calibration method and a laser processing apparatus that are used for correction using laser light.

Conventionally, a TFT (Thin Film Transistor) substrate used for a flat panel display such as a liquid crystal or an organic EL is formed by forming a fine device pattern on a glass substrate. When such a device pattern or wiring pattern is formed, a defect may occur in the pattern due to, for example, processing performed while dust or water droplets are attached to the glass substrate. A TFT substrate in which such a defect has occurred becomes a defective device and reduces the yield.
Therefore, in order to stabilize the yield of the production line at a high level, a pattern is repaired using a defect correction device (also called a repair device) and then flowed to the next process.

For example, for defects caused by so-called short-circuits where adjacent patterns are electrically connected to each other, pattern repair is performed by irradiating laser light by zapping and burning off unnecessary portions between patterns in a defect correction device. Is called. Also, for defects caused by so-called disconnections, where part of the pattern wiring is missing, laser light is emitted in a metal material gas atmosphere by a laser CVD (Chemical Vapor Deposition) method using a defect correction device. Irradiation is performed, and the pattern is repaired by rewiring the defective portion. Thus, a laser processing apparatus that requires laser processing is used as the defect correction apparatus.
For example, in Patent Document 1 below, when correcting a pattern defect by irradiating a laser beam with a laser beam, a laser irradiation region and an actual pattern image are acquired, and a reference point is acquired by performing image processing on the pattern defect to perform pattern matching. There is described a pattern correction apparatus capable of automatically correcting a pattern defect on a substrate by performing.

  Patent Document 2 describes a control device that can increase the accuracy of laser processing in a laser positioning device of a laser processing device used for laser processing such as drilling a printed circuit board or the like on which an electronic component is mounted. Yes. A control device used in this laser positioning device is configured to be able to optimally determine a command value for directing laser light to a target position on the substrate.

JP 2006-119575 A WO2003 / 080283

  In a laser processing apparatus including such a defect correction apparatus, an XY which is a galvanometer mirror for scanning a processing laser in the XY directions and a variable slit for adjusting the opening shape and the opening angle of the processing laser. Some have a -θ slit. The galvanometer mirror and the XY-θ slit are provided with a control mechanism, and are controlled according to an input signal input to the control mechanism. In order to perform laser processing, calibration of the relational expression between the input signal to the control mechanism of the galvano mirror and the position where the laser light is actually irradiated, or the input signal to the control mechanism of the XY-θ slit and the actual laser light It is necessary to calibrate the conversion coefficient of the area, shape, and angle of the irradiation region in advance.

  By the way, since the calibration work is actually performed by laser processing, the calibration work cannot be performed using a processing object such as a substrate on which an actual pattern is formed. It was necessary to make things easy separately. For this reason, the laser processing apparatus is not calibrated immediately before laser processing.

  In addition, prior to laser processing, there has been a demand for grasping the scanning state of the laser beam on the object to be processed by the galvanometer mirror and confirming where the processing is performed.

  In addition, the calibration work is usually performed from the measurement results at two or three positions. However, the accuracy at other than the measurement points is often low. A method of calibrating locally was used.

  In view of the above, the present invention provides a laser processing apparatus calibration method and a laser processing apparatus capable of performing calibration of a laser processing apparatus with high accuracy without forming a processing mark on a processing target.

  In order to solve the above problems and achieve the object of the present invention, a laser processing apparatus calibration method of the present invention comprises a laser light source that oscillates laser light and normal light, and a guide having a common laser light and optical axis. In a laser processing apparatus comprising: a guide light source that emits light; and an optical scanning unit having a control mechanism that is provided on a common optical axis for irradiating a laser beam and guide light onto a workpiece. By changing the input of the light irradiation designated position to the control mechanism of the scanning means, the step of irradiating the guide light to three or more different positions on the workpiece, and the guide light is irradiated on the workpiece. Each time, the step of obtaining the irradiation state of the guide light as an image by the observation camera provided immediately above the object to be processed, the step of measuring the guide light irradiation center position in the image by image processing, and the input to the control mechanism Kosho And the specified position, the guide light irradiating the center position measured from the image corresponding to the irradiation position specified, characterized by a step of obtaining a conversion coefficient for calibration of the optical scanning means statistically.

  The laser processing apparatus calibration method of the present invention includes a laser light source that oscillates a laser beam, a guide light source that emits a guide beam that is composed of normal light and has a common optical axis, and the laser beam and the guide beam. In a laser processing apparatus having a variable slit having a control mechanism provided on a common optical axis for adjusting the beam shape of the laser beam, by changing the input regarding the slit shape to the control mechanism of the variable slit, The process of irradiating the object with guide light with different beam shapes, and each time the guide light is irradiated onto the object to be processed, the irradiation state of the guide light is displayed as an image by the observation camera provided immediately above the object to be processed. A step of obtaining, a step of measuring the guide light irradiation shape in the image by image processing, a slit shape input to the control mechanism, and an image corresponding to the slit shape. From the guide light illumination profile, characterized by a step of obtaining a conversion coefficient for the calibration of the variable slit.

  In the laser processing apparatus calibration method of the present invention, the optical scanning means and the variable slit are calibrated by the guide light which is normal light, so that no processing trace is left on the processing object.

  The laser processing apparatus of the present invention is a laser processing apparatus that performs processing on an object to be processed with laser light, and is composed of a laser light source that oscillates laser light and normal light, and a guide having a common laser light and optical axis. A guide light source that emits light, and an optical scanning unit that has a control mechanism and is provided on a common optical axis for irradiating a laser beam and guide light onto a workpiece.

  In the laser processing apparatus of the present invention, since the guide light and the laser light have the same optical axis, the guide light and the laser light are respectively irradiated on the same portion of the processing object.

  According to the laser processing apparatus of the present invention, the optical scanning unit can be calibrated without leaving a processing mark on the processing target.

  According to the laser processing apparatus calibration method of the present invention, since the optical scanning means and the variable mirror are calibrated using the guide light, high-precision calibration is performed without leaving a processing mark on the processing object. .

  Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a schematic configuration of a laser processing apparatus according to an embodiment of the present invention. The laser processing apparatus 1 in the present embodiment is used for correcting pattern defects on a TFT substrate of a liquid crystal display, for example.
The laser processing apparatus 1 of the present embodiment includes two light sources: a laser light source 2 that oscillates a processing laser beam L, and a guide light source 7 that emits guide light G that is normal light that is not laser light. The processing laser light source 2 is used as, for example, a zapping laser light source or a CVD correction laser light source. On the optical axis of the laser light L emitted from the laser light source 2, a shutter 3 for controlling the processing time by opening and closing, a first total reflection mirror 4 for changing the optical path, and an attenuator for adjusting the amount of laser light. 5. Further, a second total reflection mirror 6 and a first half mirror 9 such as a dichroic mirror for changing the optical path are arranged. On the other hand, the condensing lens 8 and the first half mirror 9 are arranged on the optical axis of the guide light G that is normal light emitted from the guide light source 7.

  The guide light G after passing through the first half mirror 9 and the laser light L reflected by the second total reflection mirror 6 and further reflected by the first half mirror 9 have a common optical axis and In other words, the optical axes coincide with each other.

  On this common optical axis, an XY-θ slit 10, a third total reflection mirror 11, and an imaging lens 12, which are variable slits for shaping the beam shape of the laser light L to limit the processing range, are arranged. The Furthermore, a galvano mirror 13 that scans the laser light L in the XY directions, a second half mirror 14, for example, a dichroic mirror, and an objective lens 15 are disposed on a common optical axis. Under the objective lens 15, a processing target 16, for example, a substrate that is a processing target, and an XY stage 23 that is fixed and movable in the XY direction are arranged.

  Here, as shown in FIG. 2, the XY-θ slit 10 has a rectangular opening 28 having a short side length X and a long side length Y, and the rectangular opening 23 has an angle θ. With a slope of. Further, the galvanometer mirror 13 which is an optical scanning means is a mirror whose angle is variable in two dimensions.

  As the guide light source 7, for example, visible light made of an LED or the like is used, and among them, a light source that emits normal light having the same wavelength as the laser light L described above is preferably used. For example, green light is emitted. Light source to be used.

  In the laser processing apparatus 1, the laser light L emitted from the laser light source 2 enters the attenuator 5 through the shutter 3 and the first total reflection mirror 4. The laser light L whose light amount has been adjusted enters the XY-θ slit 10 through the second total reflection mirror 6 and the first half mirror 9, and is shaped into a shape that limits the processing range. The shaped laser beam L irradiates the workpiece 16 on the XY stage 23 through the third total reflection mirror 11, the imaging lens 12, the galvanometer mirror 13, the second half mirror 14, and the objective lens 15. Then, the required processing is performed on the workpiece 16. The laser light L is scanned in the X and Y directions by the galvanometer mirror 13 on the workpiece 16 such as a TFT substrate.

  The XY stage 23 is driven so as to move the processed portion on the processing target 16 into the visual field range of the objective lens 15. On the other hand, the scanning of the laser beam L with the galvanometer mirror 13 is performed in the XY directions within the field of view of the objective lens 15 on the workpiece 16.

  On the other hand, when the guide light G is emitted from the guide light source 7, the guide light G is also shaped into a beam shape by the XY-θ slit 10 and scanned on the workpiece 16 by the galvanometer mirror 13, as with the laser light L. Is done.

  Here, each of the XY-θ slit 10 and the galvanometer mirror 13 has a control mechanism (not shown), and its operation is controlled according to an input signal. In the XY-θ slit 10, the short side and the length and the angle of the long side of the opening 28 are controlled according to the input signal, and the galvano mirror 13 irradiates the workpiece 16 according to the input signal. The irradiation position of the laser beam L is controlled. Although not shown, the laser processing apparatus 1 of this example includes a control computer and can freely control the operation state of each element.

  Further, the laser processing apparatus 1 described above has a CCD camera 25 serving as an observation camera and a CCD observation system 17 having optical elements such as optical lenses 19, 20, an illumination 24, and an optical lens 21 immediately above the workpiece 16. An observation illumination system 18 having optical elements such as these is disposed. The observation illumination system 18 includes a half mirror 22, and the illumination light emitted from the illumination 24 illuminates the workpiece 16 via the half mirror 22.

  By the CCD observation system 17 and the observation illumination system 18, a processing mark on the processing target 16 by the laser light L irradiated on the processing target 16 and an image of an irradiation image by the guide light G are acquired. When it is desired to acquire an image of a processing mark, the illumination 24 provided in the observation illumination system 18 is turned on. When an image of an irradiation image by the guide light G is desired to be acquired, each image is displayed by turning off the illumination 24. Can be clearly obtained by the CCD camera 25.

  In the present embodiment, in the laser processing apparatus 1 having the above-described configuration, after the XY-θ slit 10 and the galvano mirror 13 are calibrated, processing is performed on the processing target 16 by irradiation with the laser light L. Applied.

In the laser processing apparatus 1 according to the present embodiment, the guide light source 7 is installed so that the optical axis of the guide light G and the optical axis of the laser light L are the same. If it is used for calibration of the mirror 13 and the XY-θ lens 10, calibration can be performed without leaving a processing mark on the processing target 16. Further, by scanning the guide light G, which is visible light, with the galvanometer mirror 13 before performing laser processing, it is possible to confirm in advance where the processing is performed. That is, the scanning state of the laser light G by the galvanometer mirror 13 can be grasped using the guide light G that does not leave a processing mark on the processing target 16.
The laser processing apparatus 1 is applied to, for example, a defect correction apparatus using a laser CVD method or a zapping method for correcting a defect of a wiring pattern formed on the workpiece 16.

  Next, a laser processing apparatus calibration method according to the first embodiment of the present invention will be described using the laser processing apparatus 1 shown in FIG. In the present embodiment, a calibration method for the XY-θ slit 10 and the galvanometer mirror 13 in the laser processing apparatus 1 is shown. In addition, the calibration work of the present embodiment is particularly performed using the guide light G emitted from the guide light source 7 configured to have the same optical path as the laser beam L for laser processing.

First, a method for calibrating the XY-θ slit 10 will be described. As shown in FIG. 2, the XY-θ slit 10 in the laser processing apparatus 1 has a rectangular opening 28 having a short side length X and a long side length Y. The lengths can be set as appropriate by the input values s _x and s _y . In addition, the inclination angle of the rectangular opening 28 can be arbitrarily set by an input value s _θ that determines the rotation angle of the XY-θ slit 10 in the direction indicated by the arrow θ. Here, the length X of the short side is the opening X, the length Y of the long side is the opening Y, and the inclination angle of the rectangular opening is the opening angle θ. The input values s _x , s _y and s _θ are input to the control mechanism of the XY-θ slit 10.

The XY-θ slit 10 in which the input value of the opening X is set to s _x , the input value of the opening Y is set to s _y , and the input value of the opening angle _θ is set to s _θ depends on the input values s _x , s _y , and s _θ . Controlled by input signal. Then, the guide light G is emitted from the guide light source 7. When the guide light G passes through the XY-θ slit 10, the beam shape of the guide light G is formed in a rectangular shape and is irradiated onto the workpiece 16. An example of an irradiation image on the workpiece 16 irradiated with the guide light G at that time is shown in FIG. Since visible light is used as the guide light G, the portion of the irradiation image 26a on the workpiece 16 looks bright. Therefore, the irradiation image 26 a is observed by turning off the illumination 24 of the observation illumination system 18 and capturing it with the CCD camera 25 provided in the CCD observation system 17. Assuming that measurement values of the short side length m _x , the long side length m _y , and the angle m _θ are obtained in the measurement of the irradiation image 26 a on the workpiece 16, the input values s _x and s _{y of the} XY-θ slit 10 are obtained. , S _θ and the actual measured values m _x , m _y , m _θ of the irradiation image 26a are expressed by the linear relational expression of Equation 1.

In this example, the XY-θ slit 10 is calibrated by _obtaining constants c _x0 , c _x1 , c _y0 , c _y1 , c _θ0 , and c _θ1 of the relational expression shown in Equation 1. That is, by reflecting the obtained c _x0 , c _x1 , c _y0 , c _y1 , c _θ0 , c _θ1 on the control mechanism of the XY-θ slit 10, input values s _x , s _y , s _θ to the control mechanism. The calibration of the XY-θ slit 10 is automatically optimized so that the actual measured values m _x , m _y , m _θ coincide with each other with high accuracy.

Constants c _x0 , c _x1 , c _y0 , c _y1 , c _θ0 , and c _θ1 are obtained by the following procedure.
First, the illumination 24 of the observation illumination system 18 is turned off. Next, the input value s _x of the opening X of the XY-θ slit 10, the input value s _y of the opening Y, and the input value s θ of the opening angle _θ are set. Here, the respective input values s _x , s _y , and s _θ are set to the values of Equation 2.

本例においては、ｓ_ｘ ^１＜ｓ_ｙ ^１とし、ｓ_ｘとｓ_ｙを異なる値とする。

In this example, s _x ¹ <s _y ¹ and s _x and s _y are different values.

In this case, the input value s _x of the opening X and the input value s _y of the opening Y can be set first, and then the input value s _θ of the opening angle θ can be set.

Subsequently, with the illumination 24 of the observation illumination system 18 turned off, the guide light source 7 is turned on, and the processing target 16 is irradiated with the guide light G. At this time, since the guide light G is normal light composed of an LED or the like, no processing trace is left on the processing target 16. Then, the surface state of the processing object 16 irradiated with the guide light G is captured as an image by the CCD camera 25 configured immediately above the processing object 16. An example of the image at that time is shown in FIG. Then, it performs image processing of the image shown in FIG. 3, to calculate the short side length m _x of the irradiated rectangular guide _light, long side length m _y, the measured value of the angle m _theta. As an image processing method, a particle analysis method, a pattern matching method, a Hof analysis method, or the like is used. The measured values m _x , m _y , m _θ calculated by the image processing are shown in _Equation 3.

Next, input values s _x , s _y , and s _θ for the new opening X, opening Y, and opening angle _θ are set and input to the control mechanism of the XY-θ slit 10. This new input value is shown in Equation 4.

Subsequently, the guide light G is turned on again with the illumination 24 of the observation illumination system 17 turned off, and the guide light G is irradiated onto the workpiece 16. Then, the surface state of the workpiece 16 is captured as an image by the CCD camera 25 and image processing is performed as described above. Indicating the short side length m _x of the irradiated guide light G in this _case, long side length m _y, the measured value of the angle m _theta several 5.

  By substituting the above results into the above-mentioned primary relational expression (1), each constant can be obtained from (6).

  The XY-θ slit 10 is calibrated with the constants thus determined. These calibration operations are automatically performed by a control mechanism provided in the XY-θ slit 10. Moreover, since the calibration method of this example is performed using the guide light G made of normal light, there is no processing trace left even if the processing target 16 is directly irradiated, so the actual processing target 16 is used. Calibration can be performed.

Next, a method for calibrating the galvanometer mirror 13 will be described. The galvanometer mirror 13 scans the irradiation position on the workpiece 16 based on the input value input to the control mechanism. The input value to the control mechanism of the galvanometer mirror 13 is for designating the irradiation position of the light scanned by the galvanometer mirror 13, and the coordinates (G _x , G _y ) of the input irradiation designation position and on the workpiece 16. The relationship between the center coordinates (P _x , P _y ) of the irradiation image at is expressed as shown in Equation 7 using the affine transformation matrix A.

  The affine transformation is a combination of parallel translation and linear transformation. By applying an affine transformation matrix A to the input value G, the shape is translated, enlarged / reduced, rotated, and the like. The affine transformation matrix in this example is shown in Equation 8.

Obtaining the constants a _x1 , a _x2 , a _x3 , a _y1 , a _y2 , a _y3 which are elements of the affine transformation matrix A is the calibration of the galvanometer mirror 13. In this example, in order to statistically calibrate the galvanometer mirror 13, a least square estimated value of the affine transformation matrix A is obtained using a calculation method to which the least square method is applied. Hereinafter, the least square estimated value of the affine change matrix A and its elements are shown as Equation 9.

The element of the least square estimated value of the affine transformation matrix A is obtained by the following procedure.
First, the illumination 24 of the observation illumination system 18 is turned off. Next, the coordinates (g _x , g _y ) of the designated irradiation position are set and input to the control mechanism of the galvanometer mirror 13, the guide light G is turned on, and the workpiece 16 is irradiated. The surface state of the workpiece 16 when the guide light G is irradiated is acquired by the CCD camera 25 with the illumination 24 turned off. An example of the image acquired by the CCD camera 25 at this time is shown in FIG. 4A. In this example, since normal light is used as the guide light G, the irradiation position is irradiated brightly. Further, the coordinates of the irradiation position actually measured are slightly shifted from the coordinates of the irradiation designated position to be input. Here, the coordinates of the center position of the irradiation image 26 with respect to the input coordinates (g _x , g _y ) of the designated irradiation position are defined as (p _x , p _y ). FIG. 4B shows the respective guide lights acquired by the CCD camera 25 when the input of the coordinates of the irradiation designated position and the measurement of the coordinates of the center position of the irradiation image 26 are performed five times at five positions that are not linear. An example of the irradiation image of G is shown. As described above, the coordinates of the center position (p _x ¹ ) are obtained from the image of the irradiation image 26 of the guide light G corresponding to the coordinates (g _x ¹ , g _y ¹ ) to (g _x ⁵ , g _y ⁵ ) of the designated irradiation position. , measured by ^{_{p y 1) ~ (p x}} 5, p y 5) the image processing. As an image processing method, a particle analysis method, a pattern matching method, a Hof analysis method, or the like is used.

If this series of actions is performed N times, the coordinates of the irradiation designated position for the i-th control mechanism, that is, the input value is (g _x ⁱ , g _y ⁱ ), and the coordinates of the center position of the irradiation image 26, that is, measurement. Let the values be (p _x ⁱ , p _y ⁱ ). In this example, since the calibration work is statistically performed, the measured value is observed three times or more with respect to the input value. Here, the x component A _x of the affine transformation matrix A and the i-th input value G ⁱ are shown in Equation 10.

When the x component A _x of the affine transformation matrix A and the i-th input value G ⁱ are expressed by Equation 10, the default function J _x can be expressed by Equation 11.

In the prescribed function J _x shown in Equation 11, when normalizing with respect to A _x and setting it to 0, the normal equation of Equation 12 is obtained.

このように、Ａ_ｘの最小自乗推定値が計算できる。ここで、Ａ_ｘ ^Ｔを転置行列とする。この正規方程式を展開すると数１３の行列式が得られる。

Thus, the least squares estimates of A _x can be calculated. Here, A _x ^T is a transposed matrix. When this normal equation is expanded, a determinant of Formula 13 is obtained.

In Equation 13, by applying an inverse matrix to both sides, a constant that is an element of the least square estimated value of A _x is obtained as shown in Equation 14.

Similarly, a constant that is an element of the least-square estimated value of A _y can also be obtained by the determinant of Equation 15.

  As described above, a constant in the least square estimated value of the affine transformation matrix A is obtained. The galvanometer mirror 13 is calibrated by the obtained constant. That is, in this example, the control mechanism of the galvanometer mirror 13 calibrates the coordinates between the input value and the actual measurement value, so that machining at an accurate position on the workpiece 16 is possible. These calibration operations are automatically performed by a control mechanism provided in the galvanometer mirror 13. In addition, since the calibration method of this example is performed using guide light made of normal light, there is no processing trace left even when directly irradiated onto the processing object 16, so calibration is performed using the workpiece to be actually processed. Work can be done. Further, since calibration is statistically performed based on observation results at three or more positions, high accuracy of calibration can be measured.

  In this example, in the laser processing apparatus 1 in which the XY-θ slit 10 and the galvano mirror 13 are automatically calibrated, the workpiece 16 is actually processed by the laser light L emitted from the laser light source 2. Done. In the laser processing apparatus 1 including the XY-θ slit 10 and the galvanometer mirror 13, the laser beam L is irradiated with sufficient positional accuracy with respect to the input values to the control mechanism of the XY-θ slit 10 and the galvanometer mirror 13. Therefore, highly accurate laser processing is possible. Further, since the calibration of the XY-θ slit 10 and the galvanometer mirror 13 is performed by irradiation with the guide light G, the calibration can be performed without leaving a processing mark on the processing target 16. For this reason, it is not necessary to separately prepare a workpiece for calibration work, and the calibration work can be performed immediately before laser processing. Furthermore, since there is no actual laser processing, the calibration operation can be repeated any number of times.

  In the first embodiment, the calibration method of the laser processing apparatus 1 using the guide light G is shown. However, the calibration method of the XY-θ slit 10 and the galvanometer mirror 13 shown in the first embodiment is a laser beam. The same can be done when L is used.

  Next, an example using a laser beam will be described using a laser processing apparatus 1 shown in FIG. 1 as a calibration method for a laser processing apparatus according to the second embodiment of the present invention. In the calibration method according to the present embodiment, the processing object 16 prepared separately is used instead of the processing object to be actually processed.

本例においては、ｓ_ｘ ^１＜ｓ_ｙ ^１とし、ｓ_ｘとｓ_ｙを異なる値とする。 First, a method for calibrating the XY-θ slit 10 will be described. In the present embodiment, the XY-θ slit 10 is calibrated using the laser light L emitted from the laser light source 2. Since the calculation method according to the calibration method using the relational expression of Equation 1 is the same as that in the first embodiment, a duplicate description is omitted. Therefore, in the present embodiment, a procedure for obtaining the constant in Equation 1 will be described.
First, the illumination 24 of the observation illumination system 18 is turned on. Next, the input value s _{x of} the opening X, the input value s _y of the opening Y, and the input value s θ of the opening angle _θ are set and input to the control mechanism of the XY-θ slit 10. Here, the respective input values s _x , s _y , and s _θ are set to the values of _Expression 16.

In this example, s _x ¹ <s _y ¹ and s _x and s _y are different values.

In this case, the input value s _x of the opening X and the input value s _y of the opening Y can be set first, and then the input value s _θ of the opening angle θ can be set.

Subsequently, the laser light L is oscillated from the laser light source 2 and the laser light L is irradiated onto the workpiece 16. At this time, the laser beam L leaves a processing mark on the processing target 16. The machining trace on the workpiece 16 is captured as an image by the CCD camera 25 configured in the CCD observation system 18. At this time, since an image of the processing trace can be clearly obtained, the image is captured in a state where the illumination 24 of the observation illumination system 18 is turned on. An example of the image at that time is shown in FIG. In accordance with an input value input to the control mechanism of the XY-θ slit 10, an arbitrary processing mark 27 a is formed on the processing target 16. Image processing is performed on the captured image, and the measured values of the short side length m _x , the long side length m _y , and the angle m _θ of the laser light L irradiated in a rectangular shape are calculated. As an image processing method, a particle analysis method, a pattern matching method, a Hof analysis method, or the like is used.

The illustrated short side length m _x of processing marks 27a calculated by the image _processing, long side length m _y, the measured value of the angle m _theta each number 17.

Next, the XY stage 23 is driven so that the unprocessed portion of the processing target 16 is within the field of view of the objective lens 15. Then, new input values s _x , s _y , and s _θ of the new opening X, opening Y, and opening angle _θ are set and input to the control mechanism of the XY-θ slit 10. Each of these new input values is shown in Equation 18.

Subsequently, the laser light L is again oscillated from the laser light source 2 to irradiate the workpiece 16 with the laser light L. Then, the processing mark 27a on the processing object 16 is captured as an image by the CCD camera 25 and image processing is performed as described above. The measured values of the short side length m _x , the long side length m _y , and the angle m _θ of the processing mark 27a at this time are shown in Equation 19, respectively.

  By substituting the above results into the linear relational expression shown in Equation 1, each constant can be obtained in the same manner as in the first embodiment using Equation 6. The XY-θ slit 10 is calibrated with the constants thus determined. These calibration operations are automatically performed by a control mechanism provided in the XY-θ slit 10.

Next, a method for calibrating the galvanometer mirror 13 will be described. Also in this example, the galvanometer mirror 13 is calibrated using an affine transformation matrix, as in the first embodiment. Since the calculation method in the calibration method of the galvanometer mirror 13 is the same as that of the first embodiment, a duplicate description is omitted.
Therefore, in the present embodiment, a procedure for obtaining the affine transformation matrix A when the laser light L is used for the calibration work will be described.

First, the coordinates (g _x , g _y ) of the designated irradiation position to be input to the control mechanism of the galvanometer mirror 13 are set and input, and the laser light L is oscillated from the laser light source 2 to be placed on the workpiece 16. Laser light L is irradiated. Then, a processing mark remains in the portion irradiated with the laser light L on the processing target 16. Therefore, the illumination 24 is turned on, and the image of the processing mark 27b is captured by the CCD camera 25 provided in the CCD observation system 18. An example of an image acquired by the CCD camera 25 at this time is shown in FIG. 6A. The coordinates of the center position of the machining mark 27b are assumed to be (p _x , p _y ).

Subsequently, the coordinates of another irradiation designated position are input to the control mechanism of the galvanometer mirror 13 to irradiate the processing object 16 with the laser light L, and in the same manner as described above, the processing mark of the processing object 16 is irradiated. The coordinates of the center position of 27b are measured. Then, this series of actions is repeated a plurality of times. FIG. 6B shows respective images acquired by the CCD camera 25 when the coordinates (p _x ¹ , p _y ¹ ) to (p _x ⁵ , p _y ⁵ ) of different irradiation designation positions are input. As shown in FIG. 6B, in each image, the coordinates (g _x ¹ , g _y ¹ ) to (g _x ⁵ , g _y ⁵ ) of the center position of the processing mark 27b are measured by image processing.

If this series of actions is performed N times, the coordinates of the irradiation designated position for the i-th control mechanism, that is, the input values are (g _x ⁱ , g _y ⁱ ), and the coordinates of the center position of the machining mark 27b, that is, measurement. Let the values be (p _x ⁱ , p _y ⁱ ). In the calibration work of this example, the measured value is observed three times or more with respect to the input value. From these input values and measured values, a constant that is an element of the least square estimated value of the affine transformation matrix A when the laser beam L is used is obtained.
Since the method of calculating the least square estimated value of the affine transformation matrix is the same as that of the first embodiment, a duplicate description is omitted. Therefore, the least square estimated values of the affine transformation matrices A _x and A _y can be obtained in the same manner as in the first embodiment using Equations 13 and 14, respectively.

  As described above, constants that are elements of the least-square estimated value in the affine transformation matrix A are obtained as in Expressions 14 and 15. In the present embodiment, the calibration between the coordinates of the input value and the actual measurement value of the machining mark 27b is performed in the control mechanism of the galvanometer mirror 13, so that the machining process is performed at an accurate position. These calibration operations are automatically performed by a control mechanism provided in the galvanometer mirror 13. In addition, since the calibration operation of the galvanometer mirror 13 of this example is statistically performed from the measurement results at three or more positions, the calibration can be performed with high accuracy.

  In the present embodiment, the XY-θ slit 10 and the galvanometer mirror 13 are calibrated using the laser processing apparatus 1 having the guide light source 2, but the calibration method of this example is a laser processing that does not constitute the guide light source 2. It can also be applied to devices.

By the way, in the first embodiment, the guide light source 2 is installed so that the guide light G and the optical axis of the laser beam L of the processing laser coincide with each other, but actually the optical axis is slightly shifted. There is. In such a case, as described in detail in the first embodiment, even if the galvanometer mirror 13 is calibrated using the guide light source 7, if the processing is actually performed with the laser light L, the processing position is slightly changed. Deviation occurs.
Therefore, in this case, it is preferable to perform calibration with respect to the deviation between the optical axis of the laser light L and the optical axis of the guide light G in the galvanometer mirror 13.

  Here, as a calibration method of the laser processing apparatus according to the third embodiment of the present invention, a calibration method for aligning the optical axes of the laser light and the guide light will be described. The calibration method according to the present embodiment will be described using the laser apparatus 1 shown in FIG.

とする。
次に、レーザ光Ｌを用いたガルバノミラー１３の較正をする。この、レーザ光Ｌを用いたガルバノミラー１３の較正方法は、第２の実施形態と同様であるので、重複説明を省略する。レーザ光Ｌを用いた場合のアフィン変換行列の最小自乗推定値を

とする。 First, the galvanometer mirror 13 is calibrated using the guide light G. Since the calibration method of the galvanometer mirror 13 using the guide light G is the same as that in the first embodiment, a duplicate description is omitted. In the calibration of the galvanometer mirror 13, the least square estimation value of the affine transformation matrix when the guide light G is used is

And
Next, the galvanometer mirror 13 using the laser beam L is calibrated. Since the calibration method of the galvanometer mirror 13 using the laser beam L is the same as that in the second embodiment, a duplicate description is omitted. The least square estimate of the affine transformation matrix when the laser beam L is used is

And

  Even if the galvanometer mirror 13 is calibrated using the guide light G, if the processing is actually performed with the laser light L, the processing position is slightly shifted because the affine obtained by the calibration using the actual processing traces. This is because the least square estimated value of the affine transformation matrix A obtained by calibration using the guide light G does not completely match the least square estimated value of the transformation matrix A ′. Therefore, in the relationship between the least square estimated value of the affine transformation matrix A ′ when the laser light L is used and the least square estimated value of the affine transformation matrix A when the guide light G is used, the laser light L and the guide light G If the optical axis is small and the amount of deviation is constant, for example, it is preferable to obtain the affine transformation matrix Q expressed by the following equation 19 once.

  Since the least square estimated value of the affine transformation matrix A ′ of the laser light L is obtained by applying the affine transformation matrix Q obtained by the equation 19 to the least square estimated value of the affine transformation matrix A of the guide light G, the laser is obtained. A slight optical axis shift between the light L and the guide light G is calibrated. Therefore, in addition to the calibration of the galvanometer mirror 13 performed using the guide light G, the affine transformation matrix Q, which is the calibration of the optical axes of the laser light L and the guide light G, is added to the control mechanism of the galvanometer mirror 13, so that A highly accurate calibration can be performed. Then, once this affine transformation matrix Q is obtained, the optical axis is obtained from the second calibration by the calculation shown in Equation 1 for the affine transformation matrix A obtained by calibration using the guide light G. It is possible to obtain an affine transformation matrix A ′ in which the deviation is corrected.

  According to the laser processing apparatus calibration method of the present invention, in the calibration of the galvanometer mirror, the affine transformation matrix is determined using a statistical method such as the least square method using a large number of three or more measurement points. Therefore, it is not easily affected by measurement errors, and there is no need for area division. In particular, an area where accuracy is desired can be dealt with by increasing the number of measurement points in that area. Further, when the laser processing apparatus is calibrated using the guide light, the calibration can be performed even if there is no actual processing trace by the processing laser.

  In addition, if the XY-θ slit and the galvanometer mirror are calibrated with high accuracy and have a mechanism for controlling the lighting state of the guide light, for example, an oscillation control signal input to the processing laser light source is input to the guide light source. However, as an alternative to the laser beam, the workpiece can be irradiated with guide light. By being able to irradiate the guide light as an alternative to the laser light, it is possible to grasp the scanning state of the galvanometer mirror and confirm where it is processed before laser processing. Therefore, it is possible to prevent a processing failure due to a parameter setting error or the like.

It is a schematic block diagram of the laser processing apparatus which concerns on one Embodiment of this invention. It is a schematic block diagram of XY-theta slit used for the laser processing apparatus concerning one Embodiment of this invention. It is the image taken in by the CCD camera when guide light is irradiated through the XY-θ slit on the workpiece. A and B are images when an irradiation image when a guide light is scanned on a workpiece by a galvanometer mirror is taken into a CCD camera. It is the image of the process trace taken in by the CCD camera when a laser beam is irradiated on a process target object via XY-theta slit. A and B are images when a processing mark when a laser beam is scanned on a workpiece by a galvanometer mirror is captured by a CCD camera.

Explanation of symbols

  1 .... Laser processing device, 2 .... Laser light source, 7..Guide light source, 10..XY-.theta. Lens, 13..Galvano mirror, 15..Objective lens, 16..Object to be processed, 17..Observation Illumination system, 18 ... CCD observation system, 23 ... XY stage, 24 ... illumination, 25 ... CCD camera, 26a, 26b ... Irradiation image, 27a, 27b ... processing marks

Claims (6)

A laser light source for emitting laser light;
A guide light source that is composed of normal light and emits guide light having a common optical axis with the laser beam;
In a laser processing apparatus provided with an optical scanning unit having a control mechanism provided on the common optical axis for irradiating the workpiece with the laser light and the guide light,
Irradiating the guide light to three or more different positions on the workpiece by changing the input of the light irradiation designated position to the control mechanism of the light scanning means;
Each time the guide light is irradiated onto the processing object, a step of acquiring an irradiation state of the guide light as an image by an observation camera provided immediately above the processing object;
Measuring a guide light irradiation center position in the image by image processing;
Statistically obtaining a conversion coefficient for calibration of the light scanning means from the light irradiation designated position input to the control mechanism and the guide light irradiation center position measured from the image corresponding to the light irradiation designated position. A calibration method for a laser processing apparatus, comprising: The method for calibrating a laser processing apparatus according to claim 1, further comprising a step of correcting an optical axis shift between the laser beam and the guide beam. A laser light source for emitting laser light;
A guide light source that is composed of normal light and emits guide light having a common optical axis with the laser beam;
In a laser processing apparatus comprising a variable slit having a control mechanism provided on the common optical axis for adjusting the beam shape of the laser light and the guide light,
Irradiating the processing object with the guide light having a different beam shape by changing an input related to the slit shape to the variable slit control mechanism;
Each time the guide light is irradiated onto the processing object, a step of acquiring an irradiation state of the guide light as an image by an observation camera provided immediately above the processing object;
Measuring the guide light irradiation shape in the image by image processing;
A step of obtaining a conversion coefficient for calibration of the variable slit from the slit shape input to the control mechanism and a guide light irradiation shape measured from an image corresponding to the slit shape. Device calibration method. A laser processing apparatus for processing a workpiece by laser light,
A laser light source for oscillating the laser light;
A guide light source that is composed of normal light and emits guide light having a common optical axis with the laser beam;
A laser processing apparatus comprising: an optical scanning unit having a control mechanism provided on the common optical axis for irradiating the processing object with the laser light and the guide light. The laser processing apparatus according to claim 4, wherein an observation camera and an observation illumination are configured immediately above the object to be processed. The variable slit which has a control mechanism for adjusting the beam shape of the laser beam and the guide beam on the incident side of the laser beam and the guide beam with respect to the optical scanning unit is provided. Laser processing equipment.

Images