JP2010115670A - Laser repair apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make selectable DMD units having transmission glasses corresponding to the wavelengths of laser beams. <P>SOLUTION: A laser repair apparatus includes: a laser generator 31 capable of emitting laser beams of a plurality of wavelengths; a plurality of DMD units 37a, 37b covered with optical transmission plates 40 corresponding to each wavelength of laser beams; and a slide holder 36, on which a plurality of DMD units 37a, 37b are mounted. Further, there is provided a slider controller 16 for selectively carrying out changeover by moving the slide holder 36 so that a desired DMD unit 37a (or 37b) is disposed on a laser beam path. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a laser repair apparatus that repairs a defective portion generated in, for example, an FPD glass substrate such as a liquid crystal display, a semiconductor wafer, or a printed board by irradiating a laser beam.

  FPD manufacturers such as liquid crystal displays (hereinafter referred to as “LCD”) have introduced a large number of laser repair devices and corrected them in the TFT (thin film transistor) process and the CF (color filter) process. Each manufacturer has independently improved the correction process, and there are a wide variety of correction methods and conditions. Along with this, the laser repair apparatus is required to have a multi-functional configuration, one of which is the wavelength of the laser beam used for repair.

The laser wavelength used for correction differs for each LCD manufacturer, and generally, the first to fourth harmonics of a YAG pulse laser are used.
As such a repair device, for example, in Patent Document 1, shape data of a defective portion is extracted from defect image data acquired by imaging a defective portion of a glass substrate, and a digital mirror device unit (hereinafter, referred to as a “mirror device”) is obtained according to this shape data. A technique is disclosed in which each minute mirror of a “DMD unit” is angle-controlled at high speed and a reflected laser beam is irradiated onto a defective portion.
JP 2005-103581 A

  However, the laser repair apparatus equipped with the DMD unit of Patent Document 1 cannot cope with the mounting of multiple wavelengths of lasers, and can only be used with a single laser wavelength. The DMD unit is sealed with a lid combining glass and metal for the purpose of improving the operability of the micromirror. The plate glass that seals the DMD can only transmit light of a specific wavelength depending on the material for forming the plate glass. Therefore, the conventional DMD unit on the market can only support a specific laser wavelength due to the characteristics of the plate glass.

  On the other hand, if it becomes possible to support a multi-wavelength laser in a laser repair apparatus equipped with a DMD unit, it is possible to select a laser wavelength suitable for the material in any shape and in any shape. However, a laser repair apparatus equipped with a commercially available DMD unit has not yet achieved optimum laser processing using a multi-wavelength laser.

  The present invention has been made to solve such a problem, and an object of the present invention is to provide a laser repair apparatus capable of performing optimal laser processing using a DMD unit compatible with a multi-wavelength laser.

In order to achieve the object, the invention according to claim 1
A laser light source capable of emitting laser light of multiple wavelengths;
A plurality of digital mirror device units covered with optical transmission plates corresponding to the respective wavelengths of the laser light;
A switching unit that has a base holder on which the plurality of digital mirror device units are mounted, and that selectively moves the base holder so that a desired digital mirror device unit is arranged on the laser beam path. It is characterized by.

The invention according to claim 2 is the laser repair device according to claim 1,
Each digital mirror device unit is mounted with a different installation angle on the base holder according to the wavelength of the incident laser beam.

The invention according to claim 3 is the laser repair device according to claim 2,
The installation angle can be adjusted in an arbitrary direction with respect to an attachment reference plane of the base holder.

The invention according to claim 4 is the laser repair device according to claim 1,
The switching means switches the base holder by moving it in a linear direction or a rotational direction.

The invention according to claim 5 is the laser repair device according to claim 1,
The optical transmission plate transmits at least one laser beam having a wavelength in an infrared region, a wavelength in a near ultraviolet region, or a wavelength in a deep ultraviolet region.

  That is, in the present invention, a plurality of DMD units corresponding to the wavelength region of the laser light can be mounted, and each time the laser light wavelength is switched, a DMD unit having an optical transmission plate adapted to the wavelength can be selected. did. For this purpose, there is provided switching means capable of quickly switching a desired DMD unit from among a plurality of mounted DMD units.

  According to the present invention, by using a DMD unit compatible with a multi-wavelength laser, it is possible to efficiently transmit a laser beam and efficiently process a repair target.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[First Embodiment]
FIG. 1 is a diagram illustrating an overall configuration of the laser repair apparatus according to the first embodiment.

  This laser repair apparatus 1 can switch and emit laser light having a plurality of wavelengths such as a control computer 10, a microscope optical system 20 that repairs a defective portion of a workpiece with laser light, and first to fourth harmonics of a YAG laser. A laser optical system 30.

The microscope optical system 20 and the laser optical system 30 are separated only for the convenience of explanation.
The control computer 10 includes a main control unit 11 having a central processing unit (CPU), an image processing unit 12 for input processing of image signals, a stage control unit 13, a recipe storage unit 14 for registering normal pattern images, an objective lens The switching control unit 15 controls the DMD unit 37a (or DMD unit 37b) in which a plurality of DMDs as a single two-dimensional spatial modulator are arranged in a matrix. A dimension spatial modulator control unit 17 and a laser control unit 18 are provided.

The microscope optical system 20 has a stage 21 on which the workpiece 2 to be repaired is placed.
In the present embodiment, the microscope optical system is fixed, the stage 21 is provided so as to be movable in the XY directions, and the workpiece 2 to be repaired can be moved in the XY directions. As the work 2, a fine pattern such as a TFT glass substrate, a color filter substrate, a semiconductor wafer, or a printed board is formed. Further, the XY stage 21 can be controlled to move in the XY direction within the same plane by the stage control unit 13 in order to position the defect on the optical axis of the microscope based on the defect coordinates detected by another defect inspection apparatus. ing.

  The illumination light source 22 emits illumination light for illuminating the workpiece 2. A beam splitter 24b is provided on the optical path of the illumination light via a lens 23b. An objective lens 25 is provided on the reflected light path of the beam splitter 24b. A plurality of objective lenses 25 are mounted on the objective lens switching unit 26. The objective lens switching unit 26 is controlled by the objective lens switching control unit 15 so that any one of the plurality of objective lenses 25 is selectively switched.

  On the extension of the optical axis passing through the objective lens 25 and the beam splitter 24b, an imaging unit 27 such as a CCD is provided via a beam splitter 24a and a lens 23c. The imaging unit 27 images the pattern of the work 2 through the lens 23 c and the objective lens 25 and outputs the image signal to the image processing unit 12.

  The image processing unit 12 inputs the image signal output from the imaging unit 27 to acquire defect image data, compares the defect image data with the reference image data, and determines the defect on the workpiece 2 from the difference image data. A part is extracted and binarization processing is performed to create defect shape data. Also, the defect shape data can be created by obtaining the outline of the defect portion from the defect image data or the difference image data. The image processing unit 12 outputs defect image data and defect shape data to the main control unit 11.

  Next, the laser optical system 30 includes a laser oscillator 31 that can emit laser light having a plurality of wavelengths, a fiber coupling unit 32 that introduces the emitted laser light into the optical fiber 33, and the laser light introduced into the optical fiber 33. The projection unit 34 to be output, the first laser reflection mirror 35a for reflecting the laser light emitted from the projection unit 34 toward the two-dimensional spatial modulator, and the reflection light path of the first reflection mirror 35a are provided to the beam splitter 24a. A second laser reflecting mirror 35b that reflects toward the surface, a plurality of DMD units 37a and 37b as a two-dimensional spatial modulator, and a slide holder 36 as a base holder on which the plurality of DMD units 37a and 37b are placed. Yes.

  The laser oscillator 31 emits laser beams having a plurality of wavelengths for repairing (repairing) defective portions of the work 2 based on control from the laser control unit 18. That is, as the laser oscillator 31, for example, an Nd: YAG laser light source that emits first to fourth harmonic laser light can be used. This Nd: YAG laser light source has a first harmonic (fundamental wave) of 1064 nm, a second harmonic of 532 nm, a third harmonic of 355 nm, and a fourth harmonic of 266 nm.

  A first laser reflecting mirror 35a is disposed on the optical path of the laser light emitted from the laser oscillator 31, and a DMD unit 37a (and 37b) is disposed on the reflecting optical path of the first laser reflecting mirror 35a. Yes.

FIG. 2 is an enlarged cross-sectional view of the DMD unit 37a. The DMD unit 37b has the same configuration.
The DMD unit 37 a has a large number of micromirrors 39 disposed on the upper part of the driving memory cell 38. The tilt angle of the micro mirror 39 can be controlled within a range of ± 12 ° around the torsion axis, for example. The DMD unit 37a can switch the inclination angle of each micromirror 39 at high speed by the voltage difference acting on the gap between each micromirror 39 and the drive memory cell 38.

  The micro mirror 39 rotates at a predetermined angle when the driving memory cell 38 is in the on state, and returns to the horizontal position in the off state. The micromirror 39 is a rectangular micromirror having a size of about 14 μm, for example, and the DMD unit 37a is configured by arranging a large number of micromirrors 39 on the driving memory cell 38 in a matrix.

  The micro mirror 39 of the DMD unit 37a is ON / OFF controlled by the drive memory cell 38 based on the defect shape data from the two-dimensional spatial modulator control unit 17. Thus, shaping of the projected shape of the laser light is performed by each micromirror turned on in the same shape as the defect shape in the DMD unit 37a. The laser light emitted from the DMD unit 37a enters the beam splitter 24a through the laser reflecting mirror 35b and the lens 23a. Further, the laser beam reaches the workpiece 2 through the objective lens 25, and the defect on the workpiece 2 to be repaired is irradiated with the laser beam and processed.

  The two-dimensional spatial modulator control unit 17 reads the defect shape data of each defect portion of the work 2 created by the image processing unit 12 via the main control unit 11, and each DMD unit 37a corresponding to this defect shape data. A control signal is sent to turn on the drive memory cell 38 of the micromirror 39 and turn off the drive memory cell 38 of each micromirror 39 disposed in another region.

  In this way, the angle of each micro mirror 39 of the DMD unit 37a is controlled to shape the cross-sectional shape of the laser light into the shape of the repair target, and the repair target is irradiated with the shaped laser light. .

  Further, the image processing unit 12 irradiates the defective portion of the work 2 with laser light and repairs it, then acquires image data at the same position from the imaging unit 27, compares the image data with the reference image data, It is determined from the difference image data whether or not the repair of the defective portion is complete.

  If the repair is incomplete as a result of this determination, the defect shape data of the defective portion is created again from the difference image data after the repair. Further, the two-dimensional spatial modulator control unit 17 reads the shape data of the defective portion again by the image processing unit 12, and turns on the driving memory cell 38 of each micromirror 39 of the DMD unit 37a corresponding to this shape data. To. In this way, the cross-sectional shape of the laser light is shaped so as to have a shape corresponding to the shape data of the defective portion.

  In the present embodiment, the DMD unit 37 a has a cover glass 40 as an optical transmission plate that covers the top of many micromirrors 39. The laser light reflected by the laser reflecting mirror 35a is transmitted through the cover glass 40 and reflected by the micro mirror 39, and the laser light reflected by the micro mirror 39 is transmitted through the cover glass 40 and emitted again.

FIG. 3 is a diagram showing the relationship between the wavelength of laser light and the transmittance of glass.
As shown in FIG. 3, the transmittance of the glass by the laser light varies depending on the glass material. FIG. 3 conceptually shows the relationship between the wavelength of the laser beam and the transmittance of the glass, and the numerical values are not necessarily academically accurate.

  According to FIG. 3, for example, A glass transmits well through a DUV (Deep Ultraviolet Rays deep UV) region near 266 nm, and B glass transmits well through a NUV (Near Ultraviolet Rays near UV) region near 532 nm. Furthermore, the C glass transmits well through an IR (Infrared Rays infrared) region around 532 nm to 1064 nm.

As described above, the cover glass 40 has a different transmission wavelength depending on the material. For this reason, one type of cover glass 40 cannot efficiently transmit all the wavelengths of the laser light. The laser light passes through the cover glass 40 twice at the time of incidence and at the time of emission. For this reason, even if, for example, the cover glass 40 having a transmittance of 70% is used, the overall transmittance is reduced to half, 49%. For this reason, it is preferable and important to use a cover glass 40 that is easy to transmit according to the laser light of each wavelength.

  Therefore, in the present embodiment, a cover glass 40 that easily transmits laser light having a specific wavelength is attached to each DMD unit 37a (and 37b). A plurality of DMD units 37 a (and 37 b) having these different types of cover glasses 40 are arranged in the slide holder 36. In the present embodiment, a case where two DMD units 37a (and 37b) are arranged will be described, but the number is not limited to this. For example, three or more DMD units may be mounted.

FIG. 4 is a diagram showing a configuration of the direct acting slide holder 36.
As shown in FIG. 4, in the slide holder 36, two DMD units 37a and 37b are arranged on the mounting reference surface 36a. In the slide holder 36, either one of the DMD units 37a and 37b is selectively moved via an actuator (not shown) based on control from the slider control unit 16 serving as switching means. These actuators can be selected quickly by controlling them with electrical signals. In addition, as an actuator, an electric motor, an air cylinder, etc. can be considered, for example.

  As the two DMD units 37a and 37b, for example, the slide holder 36 includes a DMD unit 37a having a wavelength corresponding to an IR (Infrared Rays infrared) region and a DMD unit 37b having a wavelength corresponding to a UV (Ultraviolet Rays ultraviolet) region. Mount.

  In this way, the workpiece 2 can be processed by switching the multi-wavelength laser light emitted from the laser oscillator 31. At this time, it is preferable to switch to the objective lens 25 corresponding to the wavelength of the laser light by the objective lens switching unit 26 according to the wavelength of the laser light. In the present embodiment, the objective lens switching unit 26 is equipped with an IR transmission objective lens and a UV transmission objective lens.

  Further, in FIG. 2 described above, for example, a number of micro mirrors 39 are arranged in the DMD unit 37a. When laser light is incident on these many micromirrors 39, they exhibit the same action as a so-called diffraction grating depending on the arrangement pitch of the micromirrors 39, the inclination angle of the micromirrors 39, and the like. For this reason, the angle at which the emitted laser light is diffracted differs depending on the wavelength of the incident laser light. In other words, depending on the wavelength of the laser light, those having a high diffraction efficiency and those not so become apparent.

  For this reason, in this embodiment, the installation angle of the DMD unit 37a (or 37b) with respect to the reference mounting surface 36a of the slide holder 36 is changed according to the wavelength of the laser light. Specifically, for example, an inclined plate (not shown) is attached to the attachment reference surface 36a, and the DMD unit 37a (or 37b) is attached on the inclined plate.

  Further, in the present embodiment, the inclined plate can be adjusted in an arbitrary direction with respect to the attachment reference surface 36a. This is because laser light in the same direction (shaped laser light) always enters the laser reflecting mirror 35b in FIG.

Next, the operation of this embodiment will be described.
The workpiece 2 assumed in the present embodiment is a TFT glass substrate, and is composed of a transparent electrode such as a metal wiring or ITO (Indium Tin Oxide). In repairing with laser light, there are cases where metal wiring is cut or ITO film is cut, and there are a plurality of materials to be repaired.

  For example, when cutting a metal wiring, it is generally considered to be processed with a laser beam in the IR wavelength region. In the case of a thin film material such as ITO, it is said that when processed with a laser in the UV region, the material is highly absorbed and can be cut efficiently.

  In the present embodiment, a normal TFT pattern image can be registered in the recipe storage unit 14, and label setting (designating a defect area) can be performed for areas such as a metal film and an ITO film. it can.

By doing so, the image processing unit 12 recognizes the defect position and pattern of the TFT glass substrate panel to be corrected, and selects the wavelength of the laser beam with high efficiency for the material to be corrected.
For example, if the correction target position is a place where the metal film is cut, an IR laser is selected as the laser light emitted from the laser oscillator 31, and the DMD unit 37a is switched to one corresponding to the IR wavelength region. Further, the objective lens 25 is switched to an IR transmission objective lens, and laser light is irradiated with a desired laser processing shape.

  For example, if the next correction target is a cut of a transparent electrode such as ITO, a UV laser is selected as the laser light emitted from the laser oscillator 31, and the DMD unit 37a is switched to a UV wavelength region compatible one. Further, the objective lens 25 is switched to a UV transmission type objective lens, and laser light is irradiated with a desired laser processing shape.

  In addition to the multi-wavelength laser processing by automatic switching by the image processing unit 12, the operator can also perform laser processing by switching the laser wavelength by manual operation.

  According to the present embodiment described above, the DMD unit 37a (and 37b) having the cover glass 40 corresponding to the wavelength of the laser light can be selected. Thereby, laser processing can be performed efficiently by switching multi-wavelength laser light with a single device. That is, it is possible to perform laser processing of an arbitrary shape by switching to a laser wavelength that is easy to process for the material to be repaired.

Also, assuming the life of a DMD unit, a spare DMD unit can be arranged and switched quickly so that even if one DMD unit is damaged, repair work can be performed continuously without stopping the device. You can continue.
[Second Embodiment]
FIG. 5 is a diagram illustrating a configuration of the slide holder 36 according to the second embodiment. In addition, the same code | symbol is attached | subjected and demonstrated to the member which is the same as that of 1st Embodiment, or corresponds.

In the present embodiment, the configuration of the slide holder 36 is different from that of the first embodiment.
That is, the slide holder 36 has a disk shape and can rotate around the rotation shaft 41. Four DMD units 37a to 37d are arranged on the reference mounting surface 36a of the slide holder 36 at equal intervals of approximately 90 °.

  In this case, for example, the DMD unit 37a and the DMD unit 37b are adapted to the wavelength region of the DUV (Deep Ultraviolet Rays deep ultraviolet) region in which the wavelength of the laser light is shorter than the UV wavelength, and the DMD unit 37c is adapted to the UV wavelength. Further, the DMD unit 37d can correspond to the IR wavelength region.

Next, the operation of this embodiment will be described.
For example, when fine processing of a transparent electrode such as ITO is required, laser processing with higher quality is possible by performing laser processing with laser light in the DUV region. However, when a laser in the DUV region is incident on the DMD unit and used, there is a high possibility that the DMD unit itself is destroyed due to high energy absorption.

Thus, when laser light in the DUV region is incident on the DMD unit, damage to the DMD unit is accumulated, and the DMD unit itself is eventually damaged.
However, in some cases, laser processing must be performed using laser light in the DUV region that may cause damage. Because the laser beam in the DUV region is highly absorbed by the material, only the transparent electrode on the surface can be cut cleanly by continuous laser irradiation with weak energy, and processing that does not damage the underlying layer is possible. Because it becomes.

  On the other hand, in the present embodiment, the DMD unit 37a and the DMD unit 37b are adapted for the wavelength region of the DUV region, so that even if one of the DMD units 37a is damaged, the spare DMD unit 37b is promptly used. The repair by the laser beam in the DUV region can be continued.

  According to the present embodiment, since the slide holder 36 is rotated, a large number of DMD units 37a to 37d can be mounted, and the DMD unit can be quickly switched by switching the wavelength of the laser beam.

  For example, even when one DMD unit fails, the repair operation can be continued by switching to a spare DMD unit without stopping the apparatus. Thereby, workability | operativity can be improved.

It is a figure which shows the whole structure of the laser repair apparatus of 1st Embodiment. It is a figure which shows the expanded cross section of a DMD unit. It is a figure which shows the relationship between the wavelength of a laser beam, and the transmittance | permeability of glass. It is a figure which shows the structure of a linear motion type slide holder. It is a figure which shows the structure of the slide holder of 2nd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Laser repair apparatus 2 Work 10 Control computer 11 Main control part 12 Image processing part 13 Stage control part 14 Recipe control part 15 Objective lens switching control part 16 Slider control part 17 Two-dimensional spatial modulator control part 18 Laser control part 20 Microscope optics System 21 XY stage 22 Illumination light source 23a Lens 23b Lens 23c Lens 24a Beam splitter 24b Beam splitter 25 Objective lens 26 Objective lens switching unit 27 Imaging unit 30 Laser optical system 31 Laser oscillator 32 Fiber coupling unit 33 Optical fiber 34 Projection unit 35a Laser Reflection mirror 35b Laser reflection mirror 36 Slide holder 36a Mounting reference surface 37a DMD unit 37b DMD unit 37c DMD unit 37d DMD unit 38 Memory cell for driving 39 Micro mirror 40 Cover Glass 41 rotation axis

Claims (5)

A laser light source capable of emitting laser light of multiple wavelengths;
A plurality of digital mirror device units covered with optical transmission plates corresponding to the respective wavelengths of the laser light;
A switching unit that has a base holder on which the plurality of digital mirror device units are mounted, and that selectively moves the base holder so that a desired digital mirror device unit is arranged on the laser beam path. A laser repair device characterized by the above. The laser repair apparatus according to claim 1, wherein each digital mirror device unit is mounted with a different installation angle on the base holder in accordance with the wavelength of the incident laser light. The laser repair device according to claim 2, wherein the installation angle is adjustable in an arbitrary direction with respect to an attachment reference surface of the base holder. The laser repair apparatus according to claim 1, wherein the switching unit switches the base holder by moving the base holder in a linear direction or a rotation direction. The laser repair device according to claim 1, wherein the optical transmission plate transmits at least one laser beam having a wavelength in an infrared region, a wavelength in a near ultraviolet region, or a wavelength in a deep ultraviolet region.

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