JP2008238229A - Laser beam machining method and apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laser beam machining method and apparatus capable of machining a secondary patterning line with high speed and accuracy based on a primary patterning line formed on a workpiece. <P>SOLUTION: The laser beam machining apparatus scans a laser beam on a workpiece (1), forming a secondary patterning line at a prescribed position, with the primary patterning line formed on the workpiece used as a reference. The scanning position of the laser beam can be corrected based on: a laser optical system for scanning a laser beam using a galvano scanning mirror (14) to the machining surface of the workpiece; an image pickup means (17) for picking up an image of the primary patterning line and laser reflected light on the machining surface of the workpiece; a compensation amount detecting means (21) which detects a relative position of the primary patterning line and the laser reflected light on the image picked up by the image pickup means and which detects an amount of compensation by comparing the relative position detected and the prescribed position of the secondary patterning line with the primary patterning line used as a reference; and based on the amount of the compensation. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  In the present invention, a workpiece supplied in-line is scanned with laser light using a galvano scan mirror, and a secondary patterning line is formed on the basis of a primary patterning line previously formed on the workpiece. More particularly, the present invention relates to a laser processing method and apparatus suitable for forming a thin film pattern for a solar cell.

  In a thin film solar cell, a photoelectric conversion element (or solar cell element) in which three layers of a first electrode, a thin film semiconductor layer, and a second electrode are stacked in a single region is a flexible insulating substrate. A large number of units are arranged in parallel, and they are connected in series to form a unit module.

  That is, the first electrode of a certain photoelectric conversion element and the second electrode of the photoelectric conversion element adjacent thereto are electrically connected, and such a series connection is made between all the photoelectric conversion elements arranged in parallel. Thus, a desired voltage can be output between the first electrode of the photoelectric conversion element positioned at one end of the unit module and the second electrode of the photoelectric conversion element positioned at the other end. For example, in order to obtain a commercial power source of AC 100V using an inverter, it is desirable to output a DC voltage of 100V or more. In a practical module, several tens or more photoelectric conversion elements are connected in series. Connected.

  The series connection structure of the photoelectric conversion elements as described above is formed by film formation of each electrode layer and photoelectric conversion layer, patterning of each layer, and a combination procedure thereof. Among these, in patterning, it is necessary to process the secondary patterning line so as to overlap the primary patterning line processed in the previous step. For such processing, laser processing with high positioning accuracy and capable of forming a fine patterning line is suitable.

  FIG. 6 shows a configuration example of a conventional laser processing apparatus. This laser processing apparatus removes the thin film by laser irradiation on the primary patterning line formed on the thin film on the film substrate 1 and rolls the secondary patterning line to process the unrolling roll of the film substrate 1. 2 and a wound roll 3 of the processed film substrate 1, and a processing stage 40 is provided on the transport path of the film substrate 1 from the unwinding roll 2 to the winding roll 3.

  The processing stage 40 is an area for irradiating the film substrate 1 with laser light to process a secondary patterning line. The film substrate 1 conveyed to the processing stage 40 is placed on the film substrate 1. When the positioning sensor 4 detects the provided marker hole, the marker hole is positioned and stopped by the processing stage 40 and is fixed to the processing stage 40 by suction.

  A processing optical unit 41 is provided below the processing stage 40. The processing optical unit 41 is mounted on an XY stage 42, and is configured such that laser light emitted from a laser oscillator 43 is incident on the processing optical unit 41 through a fiber optical system 44 made of an optical fiber. Has been. The laser light incident on the processing optical unit 41 is incident on the dichroic mirror 41 b that reflects only a specific wavelength through the incident optical system 41 a in the processing optical unit 41 and is reflected in the direction of the processing stage 40.

  Then, the laser light reflected by the dichroic mirror 41b is adjusted by the emission optical system 41c so as to be focused on the thin film on the film substrate 1, and is irradiated onto the film substrate 1. At the same time, the processing optical unit 41 is moved in the XY direction parallel to the film substrate 1 by the operation of the XY stage 42, and the laser light is scanned on the film substrate 1.

  An imaging unit 41d made of a CCD (charge coupled device) camera or the like is provided below the dichroic mirror 41b so that the laser beam and the optical axis coincide. The imaging unit 41d images an area on the film substrate 1 irradiated with the laser light via a dichroic mirror 41b (half mirror).

  Further, the laser processing apparatus includes an image processing unit 45 and a control unit 46 as processing function blocks for controlling each of the above mechanisms. The image processing unit 45 receives the input of the image signal picked up by the imaging unit 41d, performs image processing, detects the reference position coordinates of the primary patterning line formed on the thin film of the film substrate 1, and Information is output to the control unit 46. Based on the position information from the image processing unit 45, the control unit 46 controls the operations of the XY stage 42 and the laser oscillator 43 while correcting a positional shift described later, and executes the processing of the secondary patterning line.

  By the way, in the formation of a photoelectric conversion element in a practical module, since a heat treatment process is performed between the primary patterning process and the secondary patterning process, the patterning area may be shifted due to the thermal effect on the film substrate 1. is there. The coordinate system of the XY stage 42 based on an instruction from the control unit 46 and the actual 1 formed on the film substrate 1 due to the influence of meandering during positioning of the film substrate 1 and errors in positioning accuracy. There may be a deviation from the coordinate system of the next patterning area.

  Therefore, the control unit 46 calculates position information in which the above-described positional deviation is corrected according to the position information from the image processing unit 45, and designates it to the XY stage 42. An alignment procedure for correcting such a positional deviation is performed as follows, for example.

  First, the intersection of the primary patterning lines is designated as a reference position in each of the areas near the start and end of the primary patterning area on the film substrate 1. Then, the XY stage 42 is driven, and these areas are imaged by the imaging unit 41d. Based on this captured image, the image processing unit 45 detects the coordinates of each reference position and outputs them to the control unit 46. Based on these reference position coordinates, the control unit 46 corrects the position and angle with respect to the positional deviation between the coordinate system of the XY stage 42 and the coordinate system of the primary patterning area.

  Next, when processing the secondary patterning line by overlapping with the primary patterning line, the intersection on the primary patterning line to be processed is imaged by the imaging unit 41d between the reference positions, The coordinates of the intersection are acquired by image processing. Then, the control unit 46 controls the XY stage 42 and the laser oscillator 43 based on these coordinates, and processes the secondary patterning line. Similarly, a secondary patterning line is formed over the entire patterning area by repeating the acquisition of the intersection to be processed and the processing.

  In the patterning process using such a laser processing apparatus, the laser oscillator 43 and the processing optical unit 41 are connected via the fiber optical system 44 in order to perform processing by moving the processing optical unit 41 on the XY stage 42. In other words, it is difficult to increase the scanning speed of the laser beam and the productivity is low due to the fact that the inertial load of the moving body such as the processing optical unit 41 becomes large.

  On the other hand, a galvano scanning method is known as a method capable of irradiating a laser beam at a high speed by reducing an inertia load without using an XY stage for scanning the laser beam. In the galvano scanning method, a galvano scan mirror having a structure in which two reflection mirrors are rotated by a rotary drive mechanism such as a motor is used, and the reflection angle of light emitted from the laser oscillator is changed, so that X is reflected on the film substrate. It becomes possible to scan in the −Y direction at high speed.

  Among such galvano-scanning laser processing apparatuses, a laser processing apparatus that does not use an Fθ lens intended for processing on a large area generally uses a method of scanning laser light based on pre-programmed numerical data. Has been adopted. In Patent Document 1, in such a laser processing apparatus, a specific pattern provided in advance on a continuous sheet-like workpiece is imaged with an imaging camera in a fixed or stopped state, and a deviation amount from a reference position is detected. , A method of correcting based on a detected amount of deviation when scanning a laser beam using an XY galvanometer mirror and a scan lens is disclosed.

  Japanese Patent Application Laid-Open No. 2004-228561 uses a galvano scanning method to measure a position in a laser processing apparatus that forms a secondary patterning line at a position based on a primary patterning line formed on a workpiece. A position measurement step of imaging a processing surface of a workpiece placed at the imaging position and calculating position coordinate values of a plurality of points on the primary patterning line based on the imaging signal, and processing for laser irradiation A method is disclosed in which a workpiece is arranged at a position and the scanning position of the laser beam is corrected based on the position coordinate value calculated by the position measuring step.

JP-A-8-71780 JP 2005-81392 A

  In the misalignment correction method in the laser processing apparatus disclosed in Patent Document 1 above, a specific pattern provided in advance on the workpiece is used when detecting the misalignment amount by image processing. In the case where a position shift due to a thermal effect or the like has occurred in any given primary patterning line, this position shift is not reflected in the correction, so that there is a problem that the correction accuracy is low and the application range is narrow.

  Moreover, in the position shift correction method in the laser processing apparatus disclosed in Patent Document 2, the primary patterning line position measurement step by image processing and the secondary patterning line processing step are separated, so that as a whole In addition to the time required for this step, there has been a problem that the correction accuracy is reduced due to the optical axis shift between the imaging optical system in the position measurement step and the laser optical system in the processing step.

  The present invention has been made in view of such a situation, and an object thereof is to process a secondary patterning line at high speed and with high accuracy based on a primary patterning line formed on a workpiece. It is an object of the present invention to provide a laser processing method and apparatus capable of performing the above.

In order to solve the above-described problems of the prior art, the laser processing method of the present invention is formed on the workpiece by scanning the workpiece supplied in-line with a laser beam using a galvano scan mirror. In a laser processing method for forming a secondary patterning line at a predetermined position with reference to the primary patterning line,
Detecting a relative position between the primary patterning line and the laser reflected light on an image obtained by imaging the primary patterning line and the laser reflected light on the processing surface of the workpiece during laser processing; Comparing the detected relative position with a predetermined position of the secondary patterning line with reference to the primary patterning line, a correction amount is detected, and the scanning position of the laser beam is corrected based thereon. To do.

  In the laser processing method, before starting laser processing, low-intensity laser light that does not damage the workpiece is irradiated, and low-intensity laser reflected light on the primary patterning line and the processing surface of the workpiece. The relative position of the primary patterning line and the low-intensity laser reflected light is detected on the image obtained by imaging the image, and a predetermined secondary patterning line is determined based on the detected relative position and the primary patterning line. It is preferable that the initial correction amount is detected by comparing with the position of the laser beam, the laser beam scanning start position is corrected based on the detected initial correction amount, and then laser processing is started at a workable intensity.

  In the laser processing method, the step of detecting the correction amount detects the center position of the laser reflected light on the image, sets at least two detection areas at predetermined positions with reference to the center position, It is preferable to include an image processing step of calculating a correction amount from the difference in average luminance between these two detection areas.

The present invention also provides an apparatus for carrying out the laser processing method.
A laser optical system for scanning the processing surface of the workpiece with a laser beam using a galvano scan mirror;
Imaging means for imaging the primary patterning line and the laser reflected light on the workpiece surface of the workpiece;
A relative position between the primary patterning line and the laser reflected light is detected on an image obtained by imaging by the imaging means, and a predetermined position of the secondary patterning line based on the detected relative position and the primary patterning line is determined. Correction amount detection means for detecting a correction amount by comparing the position;
And a laser processing apparatus capable of correcting the scanning position of the laser beam based on the correction amount.

In the laser processing apparatus, it is preferable that the laser optical system includes an attenuator that attenuates laser light.
The imaging means is inserted between the laser oscillator and the galvano scan mirror, and transmits one of the light having the wavelength of the laser light and the light not including the wavelength of the laser light, and reflects the other. A dichroic mirror that separates light that does not include the wavelength of the laser light from light having the wavelength of the laser light, and a wavelength filter that attenuates light having the wavelength of the laser light, and the galvano scan mirror and the dichroic mirror It is preferable that the primary patterning line and the laser reflected light on the processing surface of the workpiece can be imaged via the wavelength filter.

Further, the correction amount detection means detects the center position of the laser reflected light on the image picked up by the image pickup means, and sets at least two detection areas at predetermined positions based on the center position. It is preferable to include image processing means for calculating a correction amount from the difference in average luminance between these two detection areas.
Furthermore, it is preferable to further include illumination means for illuminating the imaging range of the imaging means from a direction different from the optical axis of the laser light.

  Since the laser processing method and apparatus of the present invention are configured as described above, the following effects can be obtained.

  The primary patterning line and the laser reflected light are imaged, and the laser beam is scanned and the secondary pattern is corrected in real time during laser processing while correcting the positional deviation between the primary patterning line and the processed secondary patterning line. The patterning line can be processed, and the primary patterning line on the workpiece due to thermal influence as well as the workpiece displacement at the machining position due to meandering during positioning of the workpiece and positioning accuracy, etc. It is possible to correct the misalignment of the laser beam, and high-speed and high-precision laser processing can be performed.

  Further, since the correction amount detection based on the primary patterning line and the correction of the laser scanning position based on the detection can be performed simultaneously with the processing via the optical system common to the laser processing, the measurement of the position of the primary patterning line is possible. This process is unnecessary, and the process time of the entire processing can be shortened.

  Further, since the correction amount is detected with reference to the position of the laser reflected light, an accurate correction amount is detected even when a deviation occurs between the optical axis of the laser optical system and the optical axis of the imaging means. This eliminates the need for calibration of the optical axis deviation due to temperature change, secular change, etc., improving maintainability and reducing maintenance costs.

  Also, before starting laser processing, irradiate a low-intensity laser beam that does not damage the workpiece, detect the initial correction amount, correct the laser beam scanning start position based on it, and then processable intensity In the mode in which laser processing is started, the laser beam scanning start position can be corrected by the same control as the correction amount detection during processing through an optical system common to laser processing. High-precision laser processing can be performed in the process, and there is an advantage that the control system is simplified.

  A correction amount detection step or means based on the primary patterning line detects the center position of the laser reflected light on the image, and sets at least two detection areas at predetermined positions based on the center position. In an aspect including an image processing step or means for calculating a correction amount from a difference in average luminance between these two detection areas, an accurate correction amount can be obtained from a relative luminance difference in the imaging region regardless of the illuminance distribution in the entire processing range. Can be detected.

  Further, by providing illumination means for illuminating the imaging range of the imaging means from a direction different from the optical axis of the laser beam, the brightness difference between the processed area and the unprocessed area of the primary patterning line becomes clear, and further An accurate correction amount can be detected.

Hereinafter, the present invention will be described in detail based on illustrated embodiments.
FIG. 1 is a configuration diagram showing an outline of a laser processing apparatus according to an embodiment of the present invention. The laser processing apparatus shown in FIG. 1 is an apparatus for forming a predetermined pattern by irradiating a thin film formed on a film substrate 1 with a laser and removing the thin film in the portion. The secondary patterning line is accurately processed at a predetermined position based on the primary patterning line formed on the thin film on the film substrate 1.

  This laser processing apparatus includes an unwinding roll 2 for the film substrate 1 and a winding roll 3 for the film substrate 1 that has been processed, and is provided on the transport path of the film substrate 1 from the unwinding roll 2 to the winding roll 3. A processing stage 10 is provided.

  The processing stage 10 is an area for irradiating the film substrate 1 with laser light to process a secondary patterning line, and a large number of adsorptions are made on a flat surface arranged along the pass line of the film substrate 1. It has a hole. The film substrate 1 transported to the processing stage 10 is positioned and stopped by the processing stage 10 when the positioning sensor 4 detects a marker hole provided on the film substrate 1, and then sucked. The suction holes are fixed by suction.

  Below the processing stage 10, a laser optical system for irradiating the film substrate 1 positioned on the processing stage 10 with a laser is provided. The laser optical system includes a laser oscillator 11, an attenuator 12, a focus adjustment unit 13, a galvano scan mirror 14, and the like. The processing stage 10 and the laser optical system are covered with a light-shielding member (processing chamber) (not shown) to block disturbance light, and illuminate the processing stage 10 from a direction different from the optical axis of the laser (see FIG. Not shown).

  The laser oscillator 11 is a laser light source that emits a laser beam for processing a thin film on the film substrate 1 and is preferably an Nd: YAG laser oscillator including a wavelength conversion unit, but depending on the type of processing material, Laser light such as YAG, YLF, and YVO can also be used. The attenuator 12 has a function of attenuating the laser beam so that the laser beam emitted from the laser light source has a desired amount of light on the film substrate. It is possible to use an optical attenuator or a variable optical attenuator that can switch the amount of laser light during processing. The focus adjustment unit 13 is configured by a condensing lens or the like that can adjust the focus so that the emitted light from the laser oscillator 11 forms an image on the film substrate 1.

  The galvano scan mirror 14 is composed of a pair of reflecting mirrors (galvano mirrors) each corresponding to scanning in the X-Y direction on the processing surface, and a rotational drive mechanism such as a servo motor for rotating them. The light emitted from the oscillator 11 is reflected and guided to the processing stage 10, and the reflection angle is changed to change the reflection angle of the laser light at high speed in the XY direction on the film substrate 1 disposed on the processing stage 10. Can be scanned.

  Further, a dichroic mirror 15 (beam splitter) is provided between the laser oscillator 11 and the galvano scan mirror 14 to transmit the wavelength of the laser light and reflect the light of other wavelengths, and the reflected light from the dichroic mirror 15. A wavelength filter 16 and an imaging unit 17 are provided along the optical axis. The imaging unit 17 is configured by imaging means such as a CCD camera, and the region on the film substrate 1 irradiated with laser light via the wavelength filter 16, the dichroic mirror 15, and the galvano scan mirror 14 and the region. The reflected laser reflected light can be imaged.

  Further, the laser processing apparatus includes a surface image processing unit 21 and a control unit 22 as processing function blocks for controlling each of the above mechanisms.

  The image processing unit 21 detects a correction amount for forming the secondary patterning line based on the image captured by the imaging unit 17 and outputs the correction amount to the control unit 22. In the image data picked up by the image pickup unit 17, the region where the primary patterning line is processed has a film surface exposed by removing the thin film, and the surface becomes smoother than the unprocessed region. Since the reflection hardly occurs, the illumination light is regularly reflected, and the reflected light does not reach the galvano scan mirror 14, so that a low luminance region is obtained. On the other hand, in the unprocessed region, the metal electrode film and the semiconductor film formed by the film forming process such as sputtering or plasma CVD remain on the surface of the film substrate 1, and these surfaces are rougher than the film surface. Therefore, the illumination light is diffused and reflected, and the reflected light reaches the galvano scan mirror 14, so that a high luminance region is obtained. Therefore, the region where the primary patterning line is processed can be identified from the luminance information of such image data.

  The control unit 22 includes storage means for storing a control program and machining information in advance, and based on a predetermined coordinate value obtained from the storage means and a correction amount output from the image processing unit 21, the laser oscillator 11, the operations of the attenuator 12, the focus adjustment unit 13 and the galvano scan mirror 14 are controlled so that the film substrate 1 on the processing stage 10 is irradiated with an accurate laser beam in which the positional deviation is corrected. To do.

  Next, an outline of the operation of the laser processing apparatus based on the above embodiment will be described with reference to the drawings along a laser processing step of forming a secondary patterning line at a predetermined position with reference to the primary patterning line. In the following description, for ease of understanding, a case where a secondary patterning line is processed at the center of the primary patterning line will be described as an example.

  FIG. 2 is a flowchart showing the flow of a secondary patterning line processing step in the laser processing apparatus described above, and shows the steps until the secondary patterning line processing is completed for one primary patterning area. Yes.

  First, in step S11, the unwinding roll 2 and the winding roll 3 are rotated to convey the film substrate 1, and the conveyance is stopped by a detection signal from the positioning sensor 4, so that the film substrate 1 is processed. The next patterning area is positioned on the processing stage 10, and the film substrate 1 is sucked and fixed to the processing stage 10 in this state. Note that the operation of winding and sucking the film substrate 1 is controlled by the control unit 22 or another control circuit (not shown).

  Next, in step S12, an area for detecting the correction amount is set. FIG. 3 is a flowchart showing details of step S12, and FIG. 4 is a schematic diagram showing the relationship between the position of the laser reflected light on the image and the two correction amount detection areas A and B. In FIG. 4, the scanning direction of the galvano scan mirror 14 is the vertical direction.

  In this step S12, in step S121, the control unit 22 controls the attenuator 12 to adjust the laser light amount to an intensity that does not damage the film substrate 1, and this low light amount laser light is applied to the film substrate 1. Irradiate. Next, in step S122, the laser reflected light is imaged by the imaging unit 17, and the image processing unit 21 detects the center position C of the laser reflected light.

  Subsequently, in step S123, two correction amount detection areas A and B are set based on the center position C of the laser reflected light. At this time, the center position D between the correction amount detection areas A and B is set to a position shifted in the left-right direction by a predetermined amount corresponding to the processing content of the secondary patterning line with respect to the center position C of the laser reflected light. The correction amount detection areas A and B are set at positions where their horizontal centers coincide with the left and right edges of the virtual primary patterning line E.

  For example, when the secondary patterning line is processed at the center of the primary patterning line, the center position C of the laser reflected light and the center position D between the correction amount detection areas A and B are set to coincide with each other in the left-right direction. To do. In this case, the predetermined amount is “0”. Further, when the secondary patterning line is processed at a predetermined interval from the primary patterning line, the center position D between the correction amount detection areas A and B is determined from the image magnification with respect to the center position C of the laser reflected light. What is necessary is just to set to the position offset in the left-right direction by the predetermined interval decided.

Next, in step S13, the control unit 22 controls the galvano scan mirror 14 to move the laser beam to the processing start position. In step S14, the image processing unit 21 detects the correction amount. FIG. 5 is a schematic diagram showing a correction amount detection method. FIG. 5A shows a state where there is no misalignment, and FIG. 5B shows a case where there is a misalignment. At this time, the correction amount is expressed by the following equation.
Correction amount = k (average luminance of correction amount detection region A−average luminance of correction amount detection region B)

  Here, k is a proportional coefficient, and is determined from the relationship between the difference in average luminance and the amount of displacement. When the position of the primary patterning line F is not shifted from the center position C of the laser reflected light as shown in FIG. 5A, the average brightness of the correction amount detection areas A and B is equal, and the correction amount is “ 0 ". On the other hand, when there is a positional shift as shown in FIG. 5B, the average brightness of the correction amount detection areas A and B is different. In FIG. 5B, the average brightness of the correction amount detection area A is different. It becomes smaller than the average luminance of the correction amount detection area B, and the correction amount is detected accordingly.

  Subsequently, in step S15, the correction amount is determined. If the correction amount is “0”, that is, if there is no positional deviation, the process proceeds to the next step S17 as it is. If the correction amount is not “0”, that is, if there is a displacement, the process proceeds to step S16. In step S16, the control unit 22 controls the galvano scanning mirror 14 based on the correction amount to move the laser light, and the process returns to step S14. By repeating this loop, the positional deviation is corrected, and when the correction amount becomes “0”, the process proceeds to the next step S17.

  In step S17, the control unit 22 controls the operations of the laser oscillator 11, the attenuator 12, the focus adjustment unit 13, and the galvano scan mirror 14 to scan the laser beam with the laser beam intensity as a processable intensity. Next, patterning line is processed. During this processing, in step S18, the processing end of one patterning line is monitored, and if processing ends, the process proceeds to step S22. In step S22, it is determined whether or not all secondary patterning lines have been processed, and the process proceeds to processing of the next secondary patterning line or processing based on the determination result.

  In step S19, during the processing of the secondary patterning line, the correction amount is detected in the same manner as in step S14. If the correction amount is not “0” as in steps S15 and S16, the correction amount is set. Based on this, the galvano scanning mirror 14 is controlled by the control unit 22, and the laser beam is moved in the direction orthogonal to the scanning direction to correct the positional deviation.

  In the above processing, the primary patterning line and the laser reflected light are imaged, the positional deviation between the primary patterning line and the processed secondary patterning line is detected, and the laser beam is corrected in real time. Since the secondary patterning line is processed, the position of the workpiece on the processing position due to the meandering during positioning of the workpiece and the influence of positioning accuracy, etc., as well as on the workpiece due to thermal effects, etc. It is also possible to correct the displacement of the primary patterning line. In addition, since the misalignment is corrected through a common optical system at the same time as the processing, a separate process and apparatus for measuring the position of the primary patterning line becomes unnecessary, and the process time of the entire processing can be shortened. At the same time, the configuration of the processing apparatus is simplified.

  Further, since the correction amount is detected with reference to the position of the laser reflected light, an accurate correction amount is detected even when a deviation occurs between the optical axis of the laser optical system and the optical axis of the imaging means. It is possible to improve the maintainability because calibration for the optical axis deviation due to temperature change, secular change and the like is not necessary.

  In the above embodiment, the example in which the secondary patterning line is processed mainly at the center of the primary patterning line has been described. For example, the secondary patterning line is overlapped with a part of the primary patterning line. When forming, or when forming a secondary patterning line at a position spaced apart from a predetermined position on the primary patterning line, accurate and high-speed processing can be performed.

  In the above embodiment, the dichroic mirror 15 is provided between the laser oscillator 11 and the galvano scan mirror 14 so that the wavelength of the laser light is transmitted and the light of other wavelengths is reflected, and the reflected light from the dichroic mirror 15 is provided. Although the case where the wavelength filter 16 and the imaging unit 17 are provided along the optical axis is shown, on the contrary, the wavelength of the laser light is reflected, and light of other wavelengths is transmitted through the dichroic mirror ( A beam splitter), a wavelength filter 16 and an imaging unit 17 are provided along the optical axis of the transmitted light from the dichroic mirror, and the laser optical system (11, 12, 13) along the optical axis of the reflected light from the dichroic mirror. You may make it comprise.

  Further, in the above-described embodiment, the image processing using the difference between the average luminances of the correction amount detection areas A and B set in the image as the correction amount of the positional deviation of the primary patterning line F with respect to the center position C of the laser reflected light. However, the amount of correction of misregistration can also be detected by other image processing methods.

  For example, the edge positions on both sides of the primary patterning line F are detected from the binarized image obtained from the image captured by the imaging unit 17, and the relative position between the center position and the center position C of the laser reflected light is detected. It is also possible to detect the correction amount from a simple displacement. However, this method requires processing such as binarization of luminance data, edge position detection, center position detection, and the like, so that an image processing method using an average luminance difference is advantageous in terms of processing speed.

  In the above embodiment, the film substrate 1 is transported along the lower surface of the processing stage 10 disposed horizontally downward, and the laser optical system is provided below the processing stage 10. The direction of the stage and the conveyance direction of the film substrate are not limited to this, and can also be implemented when the film substrate 1 is conveyed in the vertical direction or the horizontal direction with respect to the processing stage arranged vertically. is there. Furthermore, the laser processing apparatus of the present invention is not limited to the processing of thin film solar cells, but can be applied not only to other workpieces supplied from a roll but also to workpieces supplied by a conveying means other than a roll. It can also be implemented.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to the said embodiment, In addition to the above, various deformation | transformation and change are possible based on the technical idea of this invention. I will add.

It is a figure which shows the structural example of the laser processing apparatus which concerns on this invention embodiment. It is a flowchart which shows the process process of the secondary patterning line in the laser processing apparatus which concerns on this invention embodiment. It is a detailed flowchart which shows a part of process process of the secondary patterning line in the laser processing apparatus which concerns on this invention embodiment. It is a schematic diagram which shows the example of a setting of the correction amount detection area | region in the image processing with the laser processing apparatus which concerns on this invention embodiment. (A) And (B) is a schematic diagram which shows the detection method of the correction amount based on the example of a setting shown in FIG. It is a figure which shows the structural example of the conventional laser processing apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Film substrate 2 Unwinding roll 3 Winding roll 10 Processing stage 11 Laser oscillator 12 Attenuator 13 Focus adjustment unit 14 Galvano scan mirror 15 Dichroic mirror 16 Wavelength filter 17 Imaging part 21 Image processing unit 22 Control unit A, B Correction amount Detection area C Center position of laser reflected light D Center position of two areas E Virtual primary patterning line F Primary patterning line

Claims (8)

A workpiece to be supplied in-line is scanned with a laser beam using a galvano scan mirror, and a secondary patterning line is formed at a predetermined position on the basis of the primary patterning line formed on the workpiece. In the laser processing method to be formed,
During laser processing, a relative position between the primary patterning line and the laser reflected light is detected on an image obtained by imaging the primary patterning line and the laser reflected light on the processing surface of the workpiece; Comparing the detected relative position with a predetermined position of the secondary patterning line with reference to the primary patterning line, a correction amount is detected, and the scanning position of the laser beam is corrected based thereon. Laser processing method.   Before starting laser processing, the laser beam is irradiated with low-intensity laser light that does not damage the workpiece, and the primary patterning line and the low-intensity laser reflected light on the workpiece surface of the workpiece are imaged. The relative position of the primary patterning line and the low-intensity laser reflected light is detected on the obtained image, and the detected relative position is compared with a predetermined position of the secondary patterning line based on the primary patterning line. 2. The laser processing method according to claim 1, wherein an initial correction amount is detected, a laser beam scanning start position is corrected based on the initial correction amount, and then laser processing is started at a processable intensity.   The step of detecting the correction amount detects the center position of the laser reflected light on the image, sets at least two detection areas at predetermined positions based on the center position, and sets the two detection areas. The laser processing method according to claim 1, further comprising an image processing step of calculating a correction amount from a difference in average luminance. Laser processing for forming a secondary patterning line at a predetermined position on the basis of the primary patterning line formed on the workpiece by scanning a laser beam on the workpiece supplied in-line. A device,
A laser optical system for scanning a laser beam on a workpiece surface of the workpiece using a galvano scan mirror;
Imaging means for imaging the primary patterning line and the laser reflected light on the workpiece surface of the workpiece;
A relative position between the primary patterning line and the laser reflected light is detected on the image obtained by imaging by the imaging means, and a predetermined position of the secondary patterning line based on the detected relative position and the primary patterning line is determined. Correction amount detection means for detecting a correction amount by comparing the position;
And a laser processing apparatus capable of correcting the scanning position of the laser beam based on the correction amount.   The laser processing apparatus according to claim 4, wherein the laser optical system includes an attenuator that attenuates laser light. The imaging means includes
The wavelength of the laser light is inserted between the laser oscillator and the galvano scan mirror, and transmits one of the light of the wavelength of the laser light and the light not including the wavelength of the laser light and reflects the other. A dichroic mirror that separates the light that does not include the wavelength of the laser light from the light of
A wavelength filter for attenuating light of the wavelength of the laser light,
The image of the primary patterning line and the laser reflected light on the processing surface of the workpiece can be imaged via the galvano scan mirror, the dichroic mirror, and the wavelength filter. 4. The laser processing apparatus according to 4. The correction amount detecting means includes
A center position of the laser reflected light is detected on the image picked up by the image pickup means, and at least two detection areas are set at predetermined positions based on the center position, and an average luminance of these two detection areas is set. The laser processing apparatus according to claim 4, further comprising an image processing unit that calculates a correction amount from the difference between the two.   The laser processing apparatus according to claim 4, further comprising an illuminating unit that illuminates an imaging range of the imaging unit from a direction different from an optical axis of the laser beam.

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