JP2006326629A - Laser beam machining apparatus and its machining method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem of chromatic aberration caused in one optical system communizing each optical path, even if a wavelength is different between a machining laser beam that is emitted to a surface to be machined and an auxiliary beam that projects an image of the surface to be machined onto the image surface of a viewing means, and to perform stable laser beam machining for a long time. <P>SOLUTION: The apparatus is equipped with the first focusing means which adjusts a distance between an opening surface for emitting a laser beam and a surface to be machined so that machining is performed on the surface by the laser beam as desired, and the apparatus is also equipped with a second focusing means which adjusts a distance between the surface to be machined and the image surface so that an image of the surface to be machined is formed on the image surface, wherein the focal position of the laser beam and that of the auxiliary beam are each separately and independently adjusted. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a laser processing apparatus and a laser processing method using the same, and more specifically, when laser processing is performed on a processing surface of the workpiece by irradiating the processing surface of the workpiece with laser light. The present invention relates to a laser processing apparatus capable of performing laser processing while observing a processing state on a processing surface of the workpiece, and a laser processing method using the same.

  Conventionally, the laser beam emitted from the laser light source is controlled through the optical system and then irradiated on the workpiece surface of the workpiece, thereby processing the workpiece surface of the workpiece into a desired state. There is known a laser processing apparatus capable of observing the processing state.

  In such a laser processing apparatus, an observation means for observing the processing state of the processing surface of the workpiece simultaneously with the processing is provided, and in general, the laser beam applied to the processing surface of the workpiece is controlled. The optical system is configured to be used as an auxiliary light optical system for projecting the image of the processing surface onto the imaging surface of the observation means, and the optical system is shared between the laser light and the auxiliary light. Has been.

  In other words, the optical system in the conventional laser processing apparatus controls the laser beam so that the processing surface is in a desired processing state, and the image of the processing surface by the auxiliary light passes through the dichroic mirror provided in the inside. The optical design is made in advance so that a part of each optical path is made common so that an image is formed on the imaging surface of the observation means.

By the way, like the above-mentioned conventional laser processing apparatus, the processing laser light for irradiating the processing surface of the workpiece and the auxiliary light for projecting the image of the processing surface onto the imaging surface of the observation means are provided. When the optical path of one optical system is commonly used for light guiding, if the wavelength of the laser light and the wavelength of the auxiliary light are different, chromatic aberration corresponding to the difference in the wavelength of each light in the optical system is caused. Would have occurred.

  Because of this chromatic aberration, for example, if priority is given to forming an image of the processing surface on the imaging surface of the observation means, a situation occurs in which the focal point of the processing laser beam does not coincide with the processing surface. Therefore, there is a problem that a desired processing state cannot be obtained.

Here, as a technique for solving the problems due to chromatic aberration as described above, for example, a technique disclosed in Japanese Patent Laid-Open No. 4-251686 presented as Patent Document 1 is known.

  The laser processing apparatus disclosed in Japanese Patent Laid-Open No. Hei 4-251686 guides the laser beam for processing and the reference light as auxiliary light in common to the optical path of the objective lens system of the microscope and focuses them on the processing site. Therefore, before processing with a laser beam, a spot shape at a processing site by a reference beam is observed with a microscope. In the laser processing apparatus disclosed in Japanese Patent Application Laid-Open No. 4-251686, a correction lens that forms an image of the processing laser beam is provided in the objective lens system of the microscope.

  This correction lens is configured by combining a convex lens and a concave lens having different refractive indexes and the same focal length. By arranging this correction lens, the focal length of the wavelength of the visible light that is the reference light is increased, while the focal length of the wavelength of the infrared light that is the processing laser light is shortened. Therefore, the focus (imaging) of visible light and the focus (imaging) of infrared light can be matched.

However, the correction lens described above needs to use a lens material having a high refractive index as the lens material of the concave lens constituting the correction lens.

Here, as the lens material having a high refractive index, for example, when zinc selenium disclosed in JP-A-4-251686 is employed, the processing laser beam is transmitted through the concave lens formed of zinc selenium. However, due to the transmission of the laser beam for processing, the concave lens gradually becomes colored, and thus the transmittance of the concave lens is lowered, and stable laser processing cannot be performed for a long time. there were.
JP-A-4-251686

  The present invention has been made in view of the various problems of the conventional techniques as described above, and the object of the present invention is the wavelength of the laser beam for processing that irradiates the workpiece surface of the workpiece. Even when the wavelength of the auxiliary light for projecting the image of the processing surface onto the imaging surface of the observation means is different, the problem of chromatic aberration that occurs in one optical system that shares each optical path is solved. An object of the present invention is to provide a laser processing apparatus capable of performing stable laser processing for a long period of time.

  Another object of the present invention is to provide a laser processing method for obtaining excellent processing results using the laser processing apparatus according to the present invention.

  In order to achieve the above object, the invention described in claim 1 of the present invention is an observing means including an imaging surface for imaging an image of a workpiece surface of a workpiece, and projects the image onto the imaging surface. A laser processing apparatus having an auxiliary light source that emits auxiliary light, and a laser oscillator that emits laser light, and a shaping unit that includes an opening surface that shapes the laser light emitted from the laser oscillator, A laser light source that emits a laser beam shaped by the opening surface of the shaping means, and an optical device that is connected to the laser light source and forms an image by entering the laser light emitted from the laser light source Comprising a dichroic mirror that transmits the laser light and reflects an image of the surface to be processed by the auxiliary light emitted from the auxiliary light source, and In the laser processing apparatus in which the imaging surface of the observation means is arranged so as to be able to capture an image of the processing surface reflected by the dichroic mirror, the processing surface is processed into a desired state by the laser light. A first focusing means for adjusting a distance between the opening surface and the processing surface; and an area between the processing surface and the imaging surface so that an image of the processing surface is formed on the imaging surface. And a second focusing means for adjusting the distance.

  According to a second aspect of the present invention, there is provided an observation means having an imaging surface for capturing an image of a surface to be processed of the workpiece and auxiliary light for projecting the image onto the imaging surface. A laser processing apparatus having an auxiliary light source, comprising: a laser oscillator that emits laser light; and a shaping means that includes an opening surface that shapes the laser light emitted from the laser oscillator to pass therethrough, and A laser light source that emits laser light shaped by the opening surface of the means, and an optical means that is connected to the laser light source and forms an image by entering the laser light emitted from the laser light source, And a dichroic mirror that reflects the laser beam and transmits the image of the surface to be processed by the auxiliary light emitted from the auxiliary light source. In the laser processing apparatus arranged so as to be capable of capturing an image of the processing surface transmitted by the dichroic mirror, the opening surface and the processing surface so that the processing surface is processed into a desired state by the laser light. A first focusing unit that adjusts a distance between the second processing unit and a second focusing unit that adjusts a distance between the processing surface and the imaging surface so that an image of the processing surface is formed on the imaging surface. And a focusing means.

  Further, the invention according to claim 3 of the present invention is the invention according to claim 1 or 2 of the present invention, wherein the first focusing means is arranged with respect to the opening surface. The distance between the opening surface and the workpiece surface is adjusted by moving the workpiece.

  Further, the invention according to claim 4 of the present invention is the invention according to claim 1 or 2 of the present invention, wherein the first focusing means is Thus, the distance between the opening surface and the surface to be processed is adjusted such that the opening surface is relatively moved.

  According to a fifth aspect of the present invention, in the invention according to any one of the first, second, third, or fourth aspect of the present invention, the first focusing means is an automatic control. Thus, the distance between the opening surface and the surface to be processed is adjusted.

  Moreover, the invention described in claim 6 among the present inventions is the invention described in any one of claims 1, 2, 3, 4 or 5 of the present invention, and further places the workpiece. In addition, a moving means that can move along a plane orthogonal to the optical path of the laser beam is provided.

  Moreover, invention of Claim 7 among this invention uses the laser processing apparatus of any one of Claim 1, 2, 3, 4, 5 or 6 among this invention, The said to-be-processed object. A laser processing method using a laser processing apparatus for processing the processing surface, wherein the distance between the opening surface and the processing surface is adjusted by the first focusing means, A first step of determining a reference position indicating a relative positional relationship between the processed surface and the opening surface when an image of the surface is focused on the imaging surface; and the processed surface of the workpiece The first processing for irradiating the laser beam from the laser light source to process the processing surface, and the positional relationship between the opening surface and the processing surface after the first processing are relatively By moving, the irradiation position of the laser beam on the surface to be processed and the opening A second step of alternately repeating a second process for changing the distance between the surface and the surface to be processed a plurality of times, and the first process and the second process in the second step. Observing the machining state of the workpiece on the workpiece surface, which is alternately repeated a plurality of times, and detecting the relative positional relationship between the opening surface and the workpiece surface when the workpiece is machined into a desired machining state. 3 and a reference position determined in the first step and a positional relationship between the opening surface detected in the third step and the surface to be processed based on a relative positional relationship. The distance between the opening surface and the processing surface is calculated by the fourth step of calculating the distance between the opening surface and the processing surface where the processing state is obtained, and the first focusing means. Distance calculated by the fourth step A fifth step of setting, by the second focusing means, in which the image of the workpiece surface is to have a sixth step of adjusting so as to focus on the imaging surface.

Here, in carrying out the present invention, the material of the workpiece is not particularly limited, but at least includes a material that absorbs light having the wavelength of the laser light emitted from the laser light source. Is.

  In the present invention, for example, various thin display devices such as a semiconductor device and a liquid crystal display device, which are particularly required to have a fine accuracy in processing, can be processed as a workpiece.

  Furthermore, in the present invention, when laser processing such a workpiece, the workpiece may be placed on a gantry having an appropriate size according to the dimensions of the workpiece.

In addition, the observation means according to the present invention can be constituted by a camera device having an imaging surface using a solid-state imaging device typified by a CCD, for example, and can capture an image of the processing surface of the workpiece. It has been made possible. This imaging surface is disposed at the rear focal point (image focal point) of the optical means according to the present invention in terms of optical design.

  Note that, for example, when a monitor device is connected to an observation means constituted by a camera device or the like, an operator can visually confirm an image picked up by the observation means by the monitor device.

  Further, for example, when an image processing apparatus is connected to an observation means constituted by a camera device or the like, an image captured by the observation means can be output to the image processing apparatus and subjected to signal processing. This result can be used as data for adjusting the first focusing means and the second focusing means.

The auxiliary light source according to the present invention is a light source that emits auxiliary light for projecting an image of a workpiece surface of a workpiece onto an imaging surface. Here, as the auxiliary light emitted from the auxiliary light source, for example, it is preferable to include light having a wavelength of 400 nm to 760 nm. However, depending on the material of the workpiece, the wavelength band with high reflectivity of the workpiece is the above-described wavelength band. When the wavelength band is outside the 400 nm to 760 nm wavelength band, ultraviolet light having a wavelength less than 400 nm, infrared light having a wavelength longer than 760 nm, or the like can be used as auxiliary light. That is, the wavelength of the auxiliary light may be appropriately selected from a wide wavelength band according to the material of the workpiece.

  More specifically, for example, a halogen lamp, a discharge lamp, or a light emitting diode (LED) can be used as the auxiliary light source.

Further, as a laser medium of the laser oscillator according to the present invention, for example, a solid laser typified by Nd: YAG can be used, but it is needless to say that the semiconductor laser is not limited thereto. An excimer laser or a carbon dioxide laser can be appropriately selected and used.

Further, the shaping means according to the present invention includes an aperture surface that allows the laser beam emitted from the laser oscillator to pass therethrough and shapes the cross-sectional shape perpendicular to the optical axis of the laser beam into the aperture shape. It is arranged at the last stage. The shaping means may be configured so that the opening shape of the opening surface is fixed in advance, but the opening shape of the opening surface may be deformed to an appropriate shape. The opening surface of the shaping means is arranged at the rear focal point (image focal point) of the optical means according to the present invention.

Here, as the laser light source according to the present invention including the laser oscillator and the shaping means, a laser light source having a conventionally known configuration can be used. For example, Japanese Patent Application Laid-Open No. 2000-164950 related to the application of the present applicant. The disclosed laser device or the like can be used. However, the laser light source according to the present invention is not limited to the multi-wavelength laser device disclosed in Japanese Patent Laid-Open No. 2000-164950, and emits only a single wavelength as the laser light source according to the present invention. Of course, a laser light source may be used.

  In consideration of the laser medium in the laser oscillator, the wavelength band of the laser light emitted from the laser light source ranges from 192 nm by the short wavelength side excimer laser to 10.6 μm by the long wavelength side carbon dioxide laser, for example. In this way, it covers a very wide wavelength band.

Further, the optical means according to the present invention can be configured to have, for example, a lens barrel portion and an objective lens portion. In this case, the imaging lens disposed in the lens barrel portion and the lens barrel portion are arranged. It can be set so as to constitute an infinite optical system by an objective lens arranged in a connected objective lens unit. This infinity optical system has a front focal point (object focal point) and a rear focal point (image focal point) by design.

  Here, when an infinite optical system is configured in the optical means according to the present invention, since the optical path is branched into two by the dichroic mirror in the present invention, there are also two rear focal points (image focal points). Become.

  The optical means according to the present invention has a laser beam for processing to be irradiated on the processing surface of the workpiece and an auxiliary light for projecting an image of the processing surface on the imaging surface of the observation means on a part of the optical path. And lead in common. For this reason, the imaging lens and the objective lens arranged so as to constitute the optical means have an aperture of the shaping means according to the present invention in consideration of chromatic aberration caused by the difference between the wavelength of the laser light and the wavelength of the auxiliary light. The optical design is such that the laser beam that has passed through the surface forms an image at a predetermined distance, and the image of the processing surface is formed on the imaging surface of the observation means by the auxiliary light.

  Note that the inventor of the present application described above for the reason described below even if the optical means is optically designed in consideration of the chromatic aberration caused by the difference between the wavelength of the laser light and the wavelength of the auxiliary light as described above. In view of the fact that the problems caused by chromatic aberration explained in the section of “Background Art” cannot be completely solved, the laser processing apparatus and the laser processing method using the same according to the present invention have been developed. It is.

  Here, the first cause that cannot completely eliminate the problem caused by chromatic aberration is that the optical design is different when the difference between the wavelength of the laser beam and the wavelength of the auxiliary beam is significant. It is extremely difficult.

  The second cause is that the optical means is assembled by using the optical components such as the objective lens and the imaging lens described above. However, there is always a tolerance in the accuracy of the assembly. Even if an optical design is made, there is actually room for problems caused by chromatic aberration.

  Further, the third cause is that there is a solid difference in the laser light incident on the optical means, so even if an ideal optical means is provided, the problem caused by chromatic aberration is actually caused. There is room to make it happen.

  Furthermore, the fourth cause is that a workpiece having a material transparent to laser light or auxiliary light, for example, when processing the inside of a liquid crystal display device, is a glass substrate or a liquid crystal display device of the liquid crystal display device. The object focal point (front focal point) varies depending on the thickness and refractive index of the functional film attached to the surface. The functional film may be, for example, a polarizing plate, a field-of-view film for increasing the viewing angle at which a liquid crystal display device can be seen well, an antireflection film or a liquid crystal display device for preventing reflection of indoor fluorescent lamps, etc. A retardation film or the like for improving the contrast is known.

The dichroic mirror according to the present invention is arranged to guide the laser beam and the auxiliary light in common to a part of the optical path of the optical means according to the present invention. Either one of the lights is reflected to bend the optical path and the other light is transmitted.

  The dichroic mirror is disposed in an inclined manner with respect to the optical path in the lens barrel portion of the optical means. The dichroic mirror according to the first aspect of the present invention is provided so as to transmit the laser light and reflect the auxiliary light. On the other hand, the dichroic mirror according to the second aspect of the present invention is provided so as to reflect the laser beam and transmit the image of the processing surface based on the auxiliary light.

  In addition, it is preferable to form an antireflection film on the dichroic mirror from the viewpoint of preventing ghosts caused by multiple reflection between the mirror reflection surface and the mirror transmission back surface in the optical means. Since this ghost is generated in both the laser light and the auxiliary light to be used, it is preferable to consider all the wavelength bands used in the optical means when forming the antireflection film. Further, since the dichroic mirror transmits or reflects laser light, the antireflection film is preferably formed of a vapor deposition film having durability against laser light.

Further, the first focusing means according to the present invention is provided between the opening surface of the shaping means provided in the laser light source and the processing surface in order to process the processing surface of the workpiece into a desired state. The distance, that is, the optical path length is adjusted. Of course, in order to adjust the distance between the opening surface of the shaping means provided in the laser light source and the surface to be processed, that is, the optical path length, for example, the shaping means may be moved. The laser light source or the optical means itself and each component constituting them may be moved, or the workpiece may be moved.

  Here, when the workpiece is moved in order to adjust the distance between the opening surface of the shaping means provided in the laser light source and the workpiece surface, the platform on which the workpiece is placed May be provided to move the gantry. Further, when configuring the moving mechanism for moving the gantry, for example, as the moving mechanism by the first focusing means, a Z-axis direction moving mechanism for controlling movement in the Z-axis direction in the XYZ orthogonal coordinate system is provided. As a moving mechanism for positioning which part of the work surface of the work piece is the irradiation target, two axes of the X axis direction and the Y axis direction for controlling the movement in the XY plane of the XYZ orthogonal coordinate system A direction moving mechanism (XY axis direction moving mechanism) is provided to constitute a three axis direction moving mechanism (XYZ axis direction moving mechanism) in the X axis direction, the Y axis direction, and the Z axis direction in the XYZ orthogonal coordinate system. May be.

  Note that, for example, a thin display device typified by a liquid crystal display device that requires fine precision in processing is selected as a workpiece, and the optical means is configured to have a lens barrel portion and an objective lens portion. At the same time, when an objective lens disposed in the objective lens unit having a high magnification of 50 times (NA = 0.4) is adopted, the depth of focus, that is, the laser beam is a beam near the processing surface. The range of the distance between the opening surface of the shaping means that can maintain the cross section of the waist and the surface to be processed is about ± 1.5 μm. That is, regarding the distance between the opening surface and the processing surface, a slight difference affects the processing state of the processing surface, so that the laser is processed so that the processing surface is processed into a desired state. In order to control the light, the minimum adjustment range by the first focusing means preferably has a resolution of about 0.2 μm. For this reason, it is preferable to perform automatic control by electric etc. about the 1st focusing means.

Further, the second focusing means according to the present invention is provided, for example, connected to the observation means, and adjusts the distance between the processing surface and the imaging surface, that is, the optical path length. . According to the second focusing unit, an image of the processing surface can be obtained without affecting the distance between the processing surface adjusted by the first focusing unit and the opening surface, that is, the optical path length. The distance between the processing surface and the imaging surface, that is, the optical path length can be adjusted so as to form an image on the imaging surface.

  Here, as exemplified above, the optical means is configured to have a lens barrel portion and an objective lens portion, and the objective lens disposed in the objective lens portion has a magnification of 50 times (NA = 0. In the case of adopting the high-magnification one of 4), when the distance between the processed surface and the opening surface is moved by 5 μm by the first focusing means, the second focusing means is connected to the processed surface and the imaging surface. The second focusing means needs to move a relatively large distance range as compared with the first focusing means so that the distance between the two needs to be moved by 12.5 mm.

  Therefore, the second focusing means does not necessarily need to be automatically controlled by electric means or the like, and can be manually controlled by an operator.

Here, the effect | action of processing the to-be-processed surface of a workpiece into a desired state with the laser processing apparatus by this invention and the laser processing method using the same is demonstrated.

  That is, the laser processing apparatus and the laser processing method using the same according to the present invention can solve the problems caused by chromatic aberration and perform laser processing stably for a long period of time. Specifically, it is intended to solve the problem caused by chromatic aberration that occurs when laser light and auxiliary light having different wavelengths are guided to optical means by sharing a part of the optical path.

  In order to obtain a clear observation image in the laser processing apparatus and the laser processing method using the same according to the present invention, it is necessary to form an image of the processing surface on the imaging surface of the observation means. In order to process the processing surface into a desired state in the laser processing apparatus and the laser processing method using the same according to the present invention, the front focal point (object focal point) of the optical design of the laser beam is made to coincide with the processing surface. Is not necessarily required.

  In addition, the laser processing apparatus and the laser processing method using the same according to the present invention can be used, for example, for defect correction in a manufacturing process of a liquid crystal display device. In the liquid crystal display device, functional parts such as wirings, TFTs, color filters and pixel electrodes are formed in a thin film on the opposing surfaces of two glass substrates, and the two glass substrates are bonded together, and a liquid crystal is provided in the gap between them. It is a sealed one. Furthermore, a functional film such as a polarizing plate, a viewing angle widening film, an antireflection film, or a retardation film is attached to the outer surface of the glass substrate for the purpose of improving the display quality of the liquid crystal display device.

  When a defect in a functional part formed on the inner surface of two glass substrates of such a liquid crystal display device is discovered and corrected by the laser processing apparatus and the laser processing method using the same according to the present invention. The wavelength of the laser beam used to correct the functional component that is the workpiece is a wavelength that passes through the glass substrate, functional film, and liquid crystal, and is absorbed by the material that constitutes the functional component that is the correction target. Thus, it is possible to correct a defect in the functional component.

  By the way, the glass substrate, the functional film, the liquid crystal, and the like described above each have a unique refractive index, spectral transmittance, thickness, etc., and their configuration is usually different depending on the product type of the liquid crystal display device. is there. Therefore, on the premise that the laser beam passes through these glass substrates, functional films, and inclusions such as liquid crystal, the control of the laser beam to process the functional component that is the surface to be processed into a desired state, chromatic aberration It is extremely difficult to carry out using optical means based on the optical design made in consideration of the problems caused by the above.

  Therefore, in the laser processing apparatus and the laser processing method using the same according to the present invention, the distance between the opening surface of the shaping means for processing the processing surface into a desired state and the processing surface is tested in advance. Thus, the distance between the opening surface and the surface to be processed is set.

  Since the present invention is configured as described above, the wavelength of the processing laser light to be irradiated onto the processing surface of the workpiece and the image of the processing surface are projected onto the imaging surface of the observation means. Even when the wavelength of the auxiliary light is different, a laser processing apparatus capable of solving the problem of chromatic aberration occurring in one optical system having a common optical path and performing stable laser processing for a long period of time. It is possible to provide an excellent effect.

  In addition, since the present invention is configured as described above, there is an excellent effect that a laser processing method for obtaining an excellent processing result using the laser processing apparatus according to the present invention can be provided.

  Hereinafter, an example of an embodiment of a laser processing apparatus and a laser processing method using the same according to the present invention will be described in detail with reference to the accompanying drawings.

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

  This laser processing apparatus 10 has a variable slit 104 as a shaping means provided with an opening surface 104a that transmits a laser beam emitted from a laser oscillator 102 and shapes a cross-sectional shape orthogonal to the optical axis of the laser beam. A laser processing microscope 200 as an optical means having a light source 100, a camera dichroic mirror 202, a laser light source mounting member 300 for optically connecting the laser light source 100 and the laser processing microscope 200, and an imaging surface 400a. The CCD camera 400 as the observation means and the workpiece M are placed, and the X-axis direction, the Y-axis direction, and the Z-axis in the XYZ orthogonal coordinate system (refer to the reference diagram showing the XYZ orthogonal coordinate system in FIG. 1). A work surface Ma and an opening surface 104 of the work M can be respectively moved in the axial direction. XYZ stage 500 that variably adjusts the distance La between the two, and a second focusing means disposed between the observation means mounting portion 204 provided in the laser processing microscope 200 and the CCD camera 400 The camera driving mechanism 600 includes an auxiliary light source 700 that emits auxiliary light for projecting an image of the processing surface Ma onto the imaging surface 400 a of the CCD camera 400.

Next, each component of the laser processing apparatus 10 described above will be described in detail. First, as the laser light source 100, a conventionally known laser light source can be appropriately employed.

  That is, as the laser oscillator 102 constituting the laser light source 100, for example, an Nd: YAG rod is provided as a laser medium in the inside thereof, and laser light having a fundamental wavelength of 1064 nm emitted from the laser medium is emitted. Can be used.

In this laser light source 100, four folding mirrors 106a, 106b, 106c, 106d, a variable attenuator 108, a λ / 2 plate (1/2 wavelength plate) 110, and a KTP (KTiOPO ₄ crystal: wavelength). Conversion element) 112, BBO (β-BaB ₂ O ₄ crystal: wavelength conversion element) 114, wavelength selection device 116, expander 118, variable slit 104, and guide light irradiation device 120 are provided. Yes.

  Here, the variable attenuator 108 is a λ / 2 plate 108a that rotates the polarization direction of the incident laser light by 90 degrees, and a polarizer that transmits only laser light having a specific linear polarization with respect to the laser light having a wavelength of 1064 nm. 108b. As the polarizer 108b, for example, a thin film polarizer, specifically, a dielectric multilayer mirror can be used.

  The KTP 112 is a nonlinear optical element that generates a second harmonic wave from the incident fundamental wave, that is, a wavelength conversion element (note that the KTP 112 transmits part of the fundamental wave), while the BBO 114 is A nonlinear optical element that generates a third harmonic or a fourth harmonic from an incident fundamental wave and a second harmonic, that is, a wavelength conversion element.

  Next, as shown in FIG. 2, the wavelength selection device 116 includes a rotatable disc 116a having four through holes and four filters 116b-1, 116b-2, 116b-3, 116b-. 4, and four filters 116b-1, 116b-2, 116b-3, 116b-4 are respectively arranged and fixed in the four through holes of the disc 116a. Here, for example, the filters 116b-1 and 116b-2 are set so as to transmit only light having a wavelength of 532 nm, and the transmittances of the two filters 116b-1 and 116b-2 are set to be different from each other. . In addition, the filters 116b-3 and 116b-4 are set so as to transmit only light having a wavelength of 355 nm, for example, and the two filters 116b-3 and 116b-4 are set to have different transmittances.

  The expander 118 has a concave lens 118a and a convex lens 118b. By adjusting the distance between the two lenses of the concave lens 118a and the convex lens 118b, the laser light incident on the expander 118 is enlarged to a predetermined outer diameter and emitted as parallel light.

  Furthermore, the variable slit 104 is configured by a plate-like object having an opening surface 104a. The sectional shape of the laser light passing through the opening surface 104a can be shaped by arbitrarily changing the opening shape of the opening surface 104a. In the laser processing apparatus 10, a variable rectangular slit using a knife edge is used as the variable slit 104.

  Next, the guide light irradiation device 120 uses the same guide light as the laser light emitted from the laser light source 100 to specify the irradiation position and irradiation range of the laser light on the processing surface Ma of the workpiece M. It is an irradiation device for emitting on the optical path. In the laser processing apparatus 10, a fiber light guide type halogen lamp is used as the guide light irradiation apparatus 120.

In the laser light source 100 having the above-described configuration, the fundamental wavelength laser light emitted from the laser oscillator 102 is bent 90 degrees by the folding mirror 106 a and then incident on the variable attenuator 108. The laser light incident on the variable attenuator 108 is attenuated and then the optical path is bent by 90 degrees by the folding mirror 106b. Then, the laser light is sequentially incident on the λ / 2 plate 110, the KTP 112, and the BBO 116, and converted in wavelength. Laser light having a plurality of different wavelengths (second harmonic, third harmonic, and fourth harmonic) is generated from the laser light.

  The laser beams having a plurality of different wavelengths generated as described above are incident on the wavelength selection device 116, and the four filters 116b-1, 116b-2, 116b-3, 116b- of the wavelength selection selection device 116 are used. By passing through any one of 4, the laser light of one of the wavelengths is selected.

  The laser light having the wavelength selected by the wavelength selection / selection device 116 in this way is incident on the expander 118, and the laser light is emitted as parallel light expanded to a predetermined outer diameter. The laser light emitted from the expander 118 is bent 90 degrees by the folding mirror 106 c and further bent by 90 degrees by the folding mirror 106 d and then enters the variable slit 104. Further, the guide light emitted from the guide light irradiation device 120 passes through the folding mirror 106d and enters the variable slit 104.

  The laser light incident on the variable slit 104 has its cross-sectional shape shaped according to the opening shape of the opening surface 104 a of the variable slit 104 and is emitted to the laser processing microscope 200.

Next, the details of the laser processing microscope 200 as optical means will be described. The laser processing microscope 200 has an objective lens (not shown) having a lens barrel portion 206 and a plurality of lens groups. And a lens unit 208. The lens barrel portion 206 is optically connected to the laser light source 100 by a laser light source mounting member 300, and the laser light emitted from the laser light source 100 is optically connected to the optical system of the lens barrel portion 206. .

  Here, the lens barrel portion 206 includes the imaging lens 210, the observation means attachment portion 204, the auxiliary light source connection portion 212, the objective lens portion connection portion 214, the illumination light dichroic mirror 216, and the camera described above. And a dichroic mirror 202 for use. Here, the illumination light dichroic mirror 216 is disposed on the objective lens unit 208 side with respect to the imaging lens 210, while the camera dichroic mirror 202 is disposed on the laser light source 100 side with respect to the imaging lens 210. It is made so that.

  Among these, the imaging lens 210 is set so that the rear focal point (image focal point) coincides with the opening surface 104 a of the variable slit 104.

  In addition, the illumination light dichroic mirror 216 is disposed at an angle of 45 degrees with respect to the optical path of the laser light positioned in the vertical direction in FIG. 1 and transmits the laser light taking the optical path in the vertical direction in FIG. The optical path of the auxiliary light emitted from the auxiliary light source 700 in the horizontal direction in FIG. 1 is bent 90 degrees and reflected so that the optical path coincides with the optical path of the laser light.

  Further, the dichroic mirror 202 for the camera is disposed at an angle of 45 degrees with respect to the optical path of the laser beam positioned in the vertical direction in FIG. 1, and transmits the laser beam taking the optical path in the vertical direction in FIG. The optical path of the reflected light from the processing surface Ma is bent 90 degrees and reflected so that the reflected light is incident on the imaging surface 400 a of the CCD camera 400.

  Further, a CCD camera 400 as an observation unit is connected to the observation unit attachment unit 204 of the lens barrel unit 206 via a camera drive mechanism 600 as a second focusing unit. The camera drive mechanism 600 can be configured by using, for example, a single-axis DC servo motor driven by a motor, the stroke is 30 mm, and the minimum moving distance can be adjusted to 0.5 mm. It is preferable that The CCD camera 400 is connected to the CRT monitor 404 by a signal line 402.

  On the other hand, an auxiliary light source 700 is attached to the auxiliary light source connection part 212 of the lens barrel part 206. In the laser processing apparatus 10, specifically, a halogen lamp is used as the auxiliary light source 700. Reference numeral 702 denotes a condensing lens for condensing auxiliary light emitted from the auxiliary light source 700.

  Furthermore, an objective lens unit 208 is attached to the objective lens unit connection unit 214 of the lens barrel unit 206. In the laser processing apparatus 10, as the objective lens disposed in the objective lens unit 208, specifically, a high-magnification objective lens with a magnification of 50 times (NA = 0.4) is used.

  Next, the XYZ stage 500 as the first focusing means and the workpiece M placed on the XYZ stage 500 will be described.

  First, the XYZ stage 500 can appropriately adopt the configuration of a conventionally known XYZ stage, and as described above, refer to the XYZ orthogonal coordinate system (reference diagram showing the XYZ orthogonal coordinate system in FIG. 1). .) Can be moved in the X-axis direction, the Y-axis direction, and the Z-axis direction, respectively, and the distance La between the work surface Ma of the work piece M and the opening surface 104a can be variably adjusted.

  More specifically, the XYZ stage 500 is a biaxial movement mechanism that drives the XYZ stage 500 in the X-axis direction and the Y-axis direction to set the irradiation position of the laser beam onto the workpiece surface Ma of the workpiece M. By driving the XY-axis direction driving mechanism and the XYZ stage 500 in the Z-axis direction and changing the distance Lb between the workpiece surface Ma of the workpiece M and the objective lens unit 208, the workpiece M is processed. A Z-axis direction drive mechanism that is a uniaxial movement mechanism that adjusts a distance La between the surface Ma and the opening surface 104a of the variable slit 104 is provided. The minimum adjustment range of the Z-axis direction moving mechanism is set to have a resolution of 0.2 μm.

  The workpiece M is a test piece obtained by applying a Cr film to a glass substrate, for example, and is placed on the XYZ stage 500.

  The camera driving mechanism 600 and the XYZ stage 500 are electrically connected to the control panel 802 via the stage control unit 800, respectively. The stage control unit 800 is configured by a computer, and the storage unit of the stage control unit 800 has an opening surface 104a and a surface to be processed for processing the surface Ma to be processed experimentally obtained in advance into a desired state. Data on the distance L to Ma is stored.

  In the laser processing apparatus 10, the camera driving mechanism 600 and the XYZ stage 500 can be moved by a desired amount of movement by operating the control panel 802.

In the above configuration, in order to process an actual product as the workpiece M using the laser processing apparatus 10, processing is performed in the following procedure. Note that the auxiliary light source 700 of the laser processing apparatus 10 is turned on in advance. That is, predetermined power is applied to the auxiliary light source 700 by a power source (not shown), and the auxiliary light source 700 is turned on. When the auxiliary light source 700 is turned on in this way, the auxiliary light emitted from the auxiliary light source 700 is reflected by the illumination dichroic mirror 216 and reaches the processing surface Ma. As the auxiliary light reaches the processing surface Ma in this way, an image of the processing surface Ma is projected onto the imaging surface 400a of the CCD camera 400.

  In addition, as the workpiece M, for example, a liquid crystal display device in which a short-circuit portion of a wiring requiring repair exists. In addition, the short circuit location of the wiring in the to-be-processed surface Ma which requires correction of the liquid crystal display device which is the to-be-processed object M shall be previously specified by XY coordinate data with the well-known test | inspection apparatus.

  First, as a first step, the workpiece M is placed on the XYZ stage 500. Then, the Z-axis direction drive mechanism of the XYZ stage 500 is driven and adjusted so that the image is focused while observing the CRT monitor 404, and the processed surface Ma and the opening surface 104a at the time of focusing are relative to each other. As a reference position indicating a proper positional relationship, a position in the Z-axis direction of the XYZ stage 500 at the time of focusing is determined as an origin, and origin position data, which is data indicating the origin position, is stored in the stage controller 800.

  Next, as a second step, laser light is emitted from the laser light source 100 to irradiate laser light onto a predetermined portion of the processing surface Ma of the workpiece M, and thereafter, the XYZ direction driving mechanism causes XYZ. The stage 500 is driven in at least one of the X-axis direction and the Y-axis direction, the XYZ stage 500 is horizontally moved at a pitch of 2 mm, and the XYZ stage 500 is moved in the Z-axis direction by a Z-axis direction driving mechanism. The XYZ stage 500 is moved in either direction along the Z-axis direction at a pitch of 0.2 μm. The irradiation of the laser beam and the movement of the XYZ stage 500 after the irradiation of the laser beam in the second step are performed by one irradiation of the laser beam and the movement of the XYZ stage 500 after the irradiation of the one laser beam. And 9 sets are repeated.

  Next, as a third step, the workpiece M, which has been subjected to 9 sets of laser light irradiation and movement of the XYZ stage 500 after the laser light irradiation in the second step, is removed from the XYZ stage 500, and 9 sets As the data indicating the relative positional relationship between the processed surface Ma and the opening surface 104a in the set of the desired processing state, the processing state of the XYZ stage 500 in the desired processing state set is observed. A position in the Z-axis direction is detected.

  Next, as a fourth step, a difference between the position in the Z-axis direction of the XYZ stage 500 in the set in which the desired machining state detected in the third step is performed and the origin position is detected, and difference data indicating this difference D is stored in the stage controller 800.

  Next, as a fifth step, the stage control unit 800 calculates the data of the distance L based on the origin position data and the difference data stored in the stage control unit 800, and uses the data of the distance L as the stage control unit. Store in 800. The calculation of the distance L is obtained by adding the above difference to the distance between the processed surface Ma and the opening surface 104a at the origin position determined in advance by design conditions and the like.

  Next, as a sixth step, a product to be actually processed as the workpiece M is placed on the XYZ stage 500, and the optical axis of the laser beam overlaps the portion to be processed in the workpiece M. The XYZ stage 500 is horizontally moved on the XY plane by the XY axis drive mechanism based on the coordinate data at the origin position of the axis, the optical axis of the laser beam is superimposed on the part to be processed in the workpiece M, and further the Z axis drive By moving the XYZ stage 500 by the difference data D in the Z-axis direction by the mechanism, the distance La between the opening surface 104a and the processing surface Ma is made to coincide with the distance L.

  Next, as a seventh step, while observing the CRT monitor 404, the CCD camera 400 is moved by the camera driving mechanism 600 to adjust the image on the CRT monitor 404 to be in focus.

  Next, as an eighth step, laser light is emitted from the laser light source 100, the laser beam is irradiated to a portion to be processed on the processing surface Ma of the workpiece M, and desired processing is performed on the irradiated portion. .

  Therefore, according to the laser processing apparatus 10, the laser beam is irradiated while observing the focused image of the workpiece M displayed on the CRT monitor 404 by performing the processes of the first to eighth steps. Thus, the processing surface Ma of the workpiece M can be processed.

After the distance L is obtained as described above, when the actual product is processed as the workpiece M using the laser processing apparatus 10, the workpiece M is placed on the XYZ stage 500 and the laser is processed. The stage controller 800 previously stores the distance La between the workpiece surface Ma of the workpiece M and the opening surface 104a of the variable slit 104 by driving the Z-axis drive mechanism of the XYZ stage 500 of the light source 100. Adjustment is performed so that the distance is the same as the distance L. Then, predetermined power is applied to the auxiliary light source 700 by a power source (not shown), and the auxiliary light source 700 is turned on.

  Then, the auxiliary light emitted from the auxiliary light source 700 is reflected by the illumination dichroic mirror 216 and reaches the processing surface Ma. As the auxiliary light reaches the processing surface Ma in this way, an image of the processing surface Ma is projected onto the imaging surface 400a of the CCD camera 400.

  Here, the camera drive mechanism 600 is driven to adjust the distance between the processed surface Ma and the imaging surface 400a so that the image displayed on the CRT monitor 404 is in focus. Thereafter, predetermined power is applied to the laser light source 100 by a power source (not shown), and laser light is emitted from the laser light source 100.

  According to an experiment by the inventor of the present application, a halogen lamp is used as the auxiliary light source 700, the laser light generated by the laser oscillator 102 of the laser light source 100 is transmitted through the filter 116b-3, and the laser light having a wavelength of 355 nm is transmitted to the processing surface Ma. It was confirmed that a desired processing state was obtained by removing a part of the Cr film on the processing surface Ma irradiated with laser light.

  As described above, according to the laser processing apparatus 10, laser light having a single wavelength of 355 nm and visible light including multiple wavelengths emitted from the halogen lamp serving as the auxiliary light source 700 are guided to the common optical path of the laser processing telescope 10. The XYZ stage 500 is driven so that the distance La between the processed surface Ma and the opening surface 104a coincides with the distance L, due to a problem caused by chromatic aberration that occurs during the exposure, that is, the deviation of the focus between the laser light and the auxiliary light. In addition to making adjustments, the camera driving mechanism 600 is driven to adjust the distance between the processed surface Ma and the imaging surface 400a so that the focus of the image displayed on the CRT monitor 404 as an observation image is in focus. In addition, it can be solved by adjusting the focal positions of the laser beam and the auxiliary light separately and independently.

Next, FIG. 3 is a schematic diagram showing the configuration of the second embodiment of the laser processing apparatus according to the present invention. With reference to FIG. 3, the second example of the laser processing apparatus according to the present invention is shown. The embodiment will be described.

  In the following description of the second embodiment of the laser processing apparatus according to the present invention, the same or equivalent configurations as those of the first embodiment of the laser processing apparatus according to the present invention described above are used. The description of the configuration and operation will be appropriately omitted by using the reference numerals.

  The laser processing apparatus 1000 and the laser processing apparatus 10 according to the second embodiment of the laser processing apparatus according to the present invention are different only in the configuration of a laser processing microscope as an optical means.

  That is, the laser processing microscope 1200 of the laser processing apparatus 1000 is configured to include a lens barrel 1202 and an objective lens unit 1204 in which an objective lens (not shown) composed of a plurality of lens groups is arranged. Yes. The lens barrel portion 1202 is optically connected to the laser light source 100 by a laser light source mounting portion 300, and the laser light emitted from the laser light source 100 is optically connected to the optical system of the lens barrel portion 1202. The

  Here, the lens barrel portion 1202 includes a laser beam imaging lens 1206, a camera imaging lens 1208, an observation means attachment portion 1210, an auxiliary light source connection portion 1212, an objective lens portion connection portion 1214, and a laser beam. And a dichroic mirror 1218 for illumination light, and a dichroic mirror 1220 for laser light.

  That is, the lens barrel portion 1202 of the laser processing microscope 1200 is provided with an observation means attachment portion 1210 for attaching a CCD camera 400 that captures an image of the work surface Ma on a vertical direction of the work piece M. A CCD camera 400 that captures an image of the processing surface Ma is disposed on the observation means mounting portion 1210 positioned vertically above M.

  As described above, in this laser processing microscope 1200, since the CCD camera 400 is disposed above the workpiece M, the laser light source 100 is moved from the top of the workpiece M and disposed. Yes.

  By adopting such a configuration, it is necessary to bend the optical path of the laser light emitted from the laser light source 100. Therefore, the laser light folding mirror 1216 is provided, and the laser light dichroic mirror 1220 is provided. Has been. The laser beam dichroic mirror 1220 is designed to reflect the laser beam and transmit the image of the processing surface Ma.

  Further, a laser beam imaging lens 1206 is disposed on the optical path between the laser beam folding mirror 1216 and the laser beam dichroic mirror 1220, while the laser beam dichroic mirror 1220 and the CCD camera 400. A dichroic mirror for illumination light 1218 and an imaging lens for camera 1208 are arranged on the optical path between the imaging surface 400a.

In the above configuration, according to an experiment by the inventor of the present application, when the laser processing apparatus 1000 is operated in the same manner as the laser processing apparatus 10 and the processing surface Ma is irradiated with the laser light, the processing target irradiated with the laser light is performed. A part of the Cr film on the processed surface Ma of the object M could be removed, and a desired processing state was obtained.

  Like the laser processing apparatus 1000, the laser beam imaging lens 1206 and the camera imaging lens 1208 are separately and independently provided, so that the influence of chromatic aberration due to the difference in wavelength between the laser beam and the auxiliary beam can be reduced. This can be further reduced.

  Further, by making it possible to exchange a plurality of types of lenses with different focal lengths as the camera imaging lens 1208, the size (magnification) of the image to be captured on the imaging surface 400a can be arbitrarily selected. .

The above-described embodiment can be modified as shown in the following (1) to (3).

  (1) In the above-described embodiment, the first focusing means is specifically configured by the XYZ stage 500, but the specific configuration of the first focusing means is limited to this. Needless to say, the laser light source 100 and the laser processing microscopes 200 and 1200 connected to the laser light source 100 or their constituent members, in particular, the opening surface 104a of the variable slit 104 are driven in the Z-axis direction. Thus, the first focusing means may be configured.

  (2) In the above-described embodiment, the type of the laser medium in the laser oscillator 102, the type of the auxiliary light source 700, the transmission wavelengths of the filters 116b-1, 116b-2, 116b-3, 116b-4, and the like are specifically described. Although shown, the specific example shown above is only an example, and it is needless to say that it is not limited thereto.

  (3) You may make it combine the above-mentioned embodiment and the modification shown in above-mentioned (1)-(2) suitably.

  The present invention can be used for processing various thin display devices such as semiconductor devices and liquid crystal display devices, for example, when processing and repairing a defective portion.

FIG. 1 is a schematic diagram showing the configuration of a first embodiment of a laser processing apparatus according to the present invention. FIG. 2 is an external perspective view illustrating the configuration of the wavelength selection device. FIG. 3 is a schematic diagram showing the configuration of the third embodiment of the laser processing apparatus according to the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Laser processing apparatus 100 Laser light source 200 Laser processing microscope 300 Laser light source attachment member 400 CCD camera 500 XYZ stage 600 Camera drive mechanism 700 Auxiliary light source 800 Stage control part 1000 Laser processing apparatus 1200 Laser processing microscope

Claims (7)

A laser processing apparatus comprising: observation means including an imaging surface that captures an image of a processing surface of a workpiece; and an auxiliary light source that emits auxiliary light that projects the image on the imaging surface,
A laser oscillator that emits a laser beam; and a shaping unit that includes an opening surface that allows the laser beam emitted from the laser oscillator to pass therethrough, and the laser beam shaped by the opening surface of the shaping unit. A laser light source that emits;
An optical means connected to the laser light source and configured to form an image by incidence of the laser light emitted from the laser light source, which transmits the laser light and uses auxiliary light emitted from the auxiliary light source. A dichroic mirror that reflects the image of the work surface;
In the laser processing apparatus arranged so that the imaging surface of the observation means can capture an image of the processing surface reflected by the dichroic mirror,
First focusing means for adjusting a distance between the opening surface and the processing surface so that the processing surface is processed into a desired state by the laser beam;
And a second focusing unit that adjusts a distance between the processing surface and the imaging surface so that an image of the processing surface is formed on the imaging surface. A laser processing apparatus comprising: observation means including an imaging surface that captures an image of a processing surface of a workpiece; and an auxiliary light source that emits auxiliary light that projects the image on the imaging surface,
A laser oscillator that emits a laser beam; and a shaping unit that includes an opening surface that allows the laser beam emitted from the laser oscillator to pass therethrough, and the laser beam shaped by the opening surface of the shaping unit. A laser light source that emits;
An optical means connected to the laser light source for forming an image by incidence of the laser light emitted from the laser light source, reflecting the laser light and using the auxiliary light emitted from the auxiliary light source Having a dichroic mirror that transmits the image of the work surface;
In the laser processing apparatus arranged so that the imaging surface of the observation means can capture an image of the processing surface transmitted by the dichroic mirror,
First focusing means for adjusting a distance between the opening surface and the processing surface so that the processing surface is processed into a desired state by the laser beam;
And a second focusing unit that adjusts a distance between the processing surface and the imaging surface so that an image of the processing surface is formed on the imaging surface. In the laser processing apparatus of any one of Claim 1 or 2,
The laser processing apparatus, wherein the first focusing means adjusts a distance between the opening surface and the processing surface by moving the workpiece with respect to the opening surface. In the laser processing apparatus of any one of Claim 1 or 2,
The first focusing means adjusts a distance between the opening surface and the processing surface so that the opening surface is moved relative to the processing surface. apparatus. In the laser processing apparatus of any one of Claims 1, 2, 3, or 4,
The laser processing apparatus, wherein the first focusing means adjusts a distance between the opening surface and the processing surface by automatic control. In the laser processing apparatus of any one of Claims 1, 2, 3, 4 or 5,
A laser processing apparatus comprising: a moving means for placing the workpiece and moving along a plane orthogonal to the optical path of the laser beam. A laser processing method using a laser processing apparatus that processes the processed surface of the workpiece using the laser processing apparatus according to claim 1. And
The distance between the opening surface and the processing surface is adjusted by the first focusing means, and the processing surface and the opening surface when the image of the processing surface is focused on the imaging surface A first step of determining a reference position indicating a relative positional relationship with
A first process for processing the processed surface by irradiating the processed surface of the workpiece with a laser beam from the laser light source, and the opening surface and the processed object after the first process. A plurality of second processes for changing the irradiation position of the laser beam on the processing surface and the distance between the opening surface and the processing surface alternately by moving the positional relationship with the surface relatively A second step that repeats times,
In the second step, the first processing and the second processing are alternately repeated a plurality of times, the processing state of the processing surface of the workpiece to be processed is observed, and processed into a desired processing state A third step of detecting a relative positional relationship between the opening surface and the processing surface;
A desired machining state is obtained based on a relative positional relationship between the reference position determined in the first step and the positional relationship between the opening surface and the surface to be processed detected in the third step. A fourth step of calculating a distance between the opening surface to be processed and the processing surface;
A fifth step of setting the distance between the opening surface and the work surface by the first focusing means to the distance calculated by the fourth step;
And a sixth step of adjusting the image of the surface to be processed to be focused on the imaging surface by the second focusing means. A laser processing method using a laser processing apparatus, comprising:

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