JP2003205376A - Method and device of repair with laser - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and device of repair with laser which is excellently maintained and has a stability, by which a material which is hardly removed with a conventional device is processable. <P>SOLUTION: A light source 100 is a CW-Q switch laser having a pulse width of 50 to 100 ns. Light emitted from the light source 100 is made incident on an optical fiber 202 after passing through an incident lens unit 200 and is guided to a microscope 300 by the optical fiber 202. Thereafter the light is made incident on the microscope 300 after being collimated with a collimate lens unit 204 provided at the top end of the microscope 300. The light passed through the optical path inside the microscope 300 is condensed on an object to be processed 500 with an object lens 312 in a form based on a beam forming slit 306, thus a machining is processed. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser repair method and apparatus for repairing a wiring pattern using laser light, and more particularly to a laser repair method and apparatus suitable for repairing a black defect in a plasma display.

[0002]

2. Description of the Related Art Photolithography technology is used for manufacturing circuits in the liquid crystal and semiconductor fields. In the manufacturing process, defects may occur in the pattern due to dust or the like. The defects include
There are white defects (open defects) that are not connected where they should be connected, and black defects (short defects) that are connected where they should be separated.

Regarding black defects, conventionally, N of pulse excitation is used.
The target portion is irradiated with d: YAG laser through the microscope optical system to remove and correct it. The main specifications of the laser used at this time are illustrated below. Wavelength is 1064n
m, 532 nm, 355 nm, 266 nm, the frequency is 1 to 30 Hz, and the pulse energy is 10 mJ.
And the pulse width is about 5 ns (nanosecond).

[0004]

By the way, a metal thin film of aluminum, molybdenum, copper or the like, or a transparent oxide conductive film of ITO (indium-tin oxide) or the like is used for the circuit material of the liquid crystal and the semiconductor. . Each of these film thicknesses is several thousand angstroms.

On the other hand, the wiring normally used in plasma displays is a silver electrode. The film thickness is about 10 μm, which is extremely thick compared to the film material described above. Therefore, when the laser having the above specifications is used for processing, the laser beam is absorbed only on the surface of the material, the heat is not transmitted to the inside, and the removal performance is not improved. As a result, a large number of pulses are required, the processing time becomes long, and the risk of damaging the glass of the substrate increases. In addition, it may be difficult to completely remove it by normal processing. In this case, the defective portion of the pattern is not completely corrected, which causes a malfunction.

Further, when processing a part for a plasma display with a conventional device, there is a problem caused by the device configuration. The object to be processed for plasma display is usually about 1
It is a glass plate of about m square. If the processing optical system is fixed and the stage on which the glass plate is placed is moved, the device becomes huge. Therefore, usually, in order to make the device compact, the glass plate is fixed and the processing part is moved.

In the conventional thin film processing, a laser oscillating in a few nanoseconds was mounted on a microscope. As a result, when the processing part is moved, the microscope and laser move on the stage. The laser oscillator is composed of delicate mechanical parts and is liable to cause problems such as misalignment due to vibration caused by stage movement. In addition, since a laser with a repetition frequency of several Hz or higher uses a water cooling system, a tank containing cooling water moves on the substrate. Not only is there a risk of water leaks, but maintenance is also restricted.
In addition, when the device configuration is such that the laser is not mounted on the stage and is transmitted by an optical fiber, the laser pulse width is several nanoseconds and the peak power is high, so the fiber is damaged and sufficient output cannot be transmitted. . Furthermore, when the laser light is transmitted by a set of mirrors, the laser beam diameter changes depending on the transmission distance, and when the beam is cut out by a slit, the energy density changes depending on the location.

The present invention has been made in view of the above problems, and an object of the present invention is to enable processing of a substance which is difficult to remove by a conventional apparatus, and
An object of the present invention is to provide a stable laser repair method and a laser repair device having excellent maintainability.

[0009]

In order to solve the above problems, a first invention of the present invention is a laser repair method for repairing a defective portion of a wiring pattern by using a laser beam and has a pulse width of 50 to 150 ns. There is provided a laser repairing method characterized by using the laser beam.

According to this structure, it is possible to remove an electrode substance having a film thickness of about 10 μm, which has been difficult to remove in the past. In the removal processing of the electrode material having a film thickness of about 10 μm, the energy per unit time becomes low with a laser beam having a pulse width longer than 50 to 150 ns, and the temperature cannot be raised so much that the removal material evaporates. Laser light having a pulse width shorter than 50 to 150 ns does not conduct heat to the deep part of the film and cannot be removed well.

A second invention of the present invention is a laser repair device for repairing a defective portion of a wiring pattern by using a laser beam, wherein the laser beam having a pulse width of 50 to 150 ns is used. Provide a repair device.

By using the apparatus having such a structure, it is possible to remove an electrode substance having a film thickness of about 10 μm, which has been difficult to remove in the past. As a laser light source of this laser light, for example, a continuous excitation Q switch Nd: YAG
A laser can be used.

At that time, an optical fiber for guiding the laser light from the laser light source, an incident optical system for guiding the laser light emitted from the laser light source to the optical fiber, and a light emitted from the optical fiber are provided. It is preferable to have a collimating optical system for collimating.

By guiding the light from the light source using an optical fiber, the irradiation energy density can be kept constant even if the irradiation position changes. By the incident optical system,
The light from the light source can be efficiently guided to the optical fiber. For the incident optical system, for example, an incident lens unit including a lens having a light condensing function can be used. The collimating optical system can collimate the light emitted from the optical fiber, and the collimated light can be incident on the processing optical system.

Further, it is preferable to have a slit for shaping the beam diameter and the cross-sectional shape of the laser light into a desired shape, and an observing means for observing the irradiation area of the laser light on the surface to be processed.

With the slit, the beam diameter and the cross-sectional shape of the laser light can be shaped according to the size and shape of the processed portion. Moreover, since the irradiation area of the laser beam after shaping on the surface to be processed can be observed, the processing operation can be performed while confirming the processing shape and the processing area. A CCD camera or the like can be used as the observation means.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a configuration diagram of a laser repair device according to an embodiment of the present invention. Here, for convenience, an XYZ coordinate system is set as shown in FIG. That is, the Z axis is along the normal direction of the processing object 500, the Y axis is in the direction parallel to the paper surface of FIG. 1 in the surface of the processing object 500, and the Z axis is perpendicular to the paper surface of FIG. 1 in the surface of the processing object 500. The X-axis is set in each direction.

A lamp-excited water-cooled CW-Q switch Nd: YAG laser is used as the processing light source 100. This laser light has a wavelength of 1.064 μm,
The pulse width is about 100 ns. The laser light emitted from the light source 100 is condensed by the incident lens unit 200 and guided to the optical fiber 202.

The optical fiber 202 is used as an optical transmission means between the light source 100 and the microscope 300. As a result, even if the irradiation position changes, the beam diameter on the irradiation surface becomes constant, and the irradiation energy density can be kept constant.

The laser light emitted from the optical fiber 202 enters a collimator lens unit 204 mounted at the tip of the top of the microscope 300. Collimating lens unit 2
Reference numeral 04 designates a collimating optical system, and the optical fiber 2
The light emitted from 02 is collimated and made incident on the microscope 300. In the present embodiment, the beam diameter of the parallel light is about 3φ.

Here, a laser microscope 300 is used as an optical system for irradiating the workpiece 500 with laser light. The microscope 300 includes a dichroic mirror 3
02a, 302b, half mirror 302c, slit-shaped illumination light source 304, beam shaping slit 306, relay lenses 308a, 308b, total reflection mirror 310,
Objective lens 312, epi-illumination light source 314, observation CC
It is equipped with a D camera 316 and the like. Here, the dichroic mirror 302a transmits laser light having a wavelength of 1.064 μm and reflects visible light. The dichroic mirror 302b is a mirror that reflects laser light having a wavelength of 1.064 μm and transmits visible light. The laser light incident on the microscope 300 is transmitted through the dichroic mirror 302a, and the guide light from the slit-shaped illumination light source 304 provided on the side of the microscope 300 is reflected by the dichroic mirror 302a, and these two types of light are dichroic mirrors. 302a is combined.

This combined light beam has a beam shaping slit 306.
Is shaped so as to have a desired cross-sectional shape and a desired size. The beam shaping slit 306 is an electric slit, and the slit size can be set arbitrarily. After that, the combined light passes through the relay lens 308a, is reflected by the total reflection mirror 310 and the dichroic mirror 302b, passes through the objective lens 312, and then is processed.
00 is irradiated. The slit shape is reduced and imaged on the object to be processed 500 by the objective lens 312. As a result, laser light having a desired beam diameter and cross-sectional shape is applied to the object 500 to be processed, and processing is performed.

The light emitted from the epi-illumination light source 314 is reflected by the half mirror 302c, transmitted through the dichroic mirror 302b, and transmitted through the objective lens 312 to illuminate the object to be processed 500 and the object to be processed 5
It is reflected at 00. This reflected light is returned to the objective lens 31 again.
2, an observation CCD camera 31 attached to the top end of the microscope 300 through the dichroic mirror 302b, the half mirror 302c and the relay lens 308b.
It is incident on 6. By the observation CCD camera 316, the irradiation area of the laser beam on the processing object 500 can be observed, and the processing can be performed while confirming the processing shape and processing state.

The workpiece 500 is placed on the table 400. The table 400 is a chuck type table, and the workpiece 500 may be positioned by an air flow method.

The microscope 300 is constructed so as to be movable in the XY plane and can irradiate a desired position on the object 500 to be processed with laser light. Also, the microscope 300 and the table 4
00 is configured to be relatively movable in the Z direction, and can be processed after the focus position of the objective lens 312 and the surface to be processed are accurately aligned.

Here, the removal processing using a laser will be briefly described. When the removal material is irradiated with the laser, the laser light is absorbed by the removal material. If the material to be removed has a large thickness, such as silver paste, the surface temperature will rise first. Then, the removed substance is melted and evaporated, and its heat is conducted inside the substance.

In the device of the above embodiment, a CW-Q switch laser having a pulse width of 50 to 150 ns (nanosecond) is used as the light source. The correlation between pulse width and power is shown in FIG. The horizontal axis of FIG. 2 represents time and the vertical axis represents power. The solid line and the one-dot chain line show the power distributions of lasers having the same energy amount and pulse widths of 10 ns and 100 ns, respectively.
As shown in FIG. 2, for the same energy amount, the longer the pulse width, the smaller the power. Therefore, the pulse width is 5
When it is longer than 0 to 150 ns (nanosecond), the power becomes small, and the temperature may not be increased enough to evaporate depending on the removed substance. Pulse width is 50 to 150
If it is shorter than ns (nanosecond), the power becomes large, but since the irradiation time is short, the removed substance having a large film thickness does not conduct heat to the deep part of the film and cannot be removed well.

A processing example using the laser repair apparatus of this embodiment will be described. FIG. 3 shows a partial top view of a linear silver electrode. The silver electrode 50 is formed on the glass substrate 52. The width direction of the silver electrode 50 is the x direction, and the length direction is the y direction. FIG. 4A shows the measurement result of the film thickness of the silver electrode 50 in the x direction before processing. In FIG. 4A, the horizontal axis represents the position in the x direction, and the vertical axis represents the glass substrate 52.
Represents the height in the direction perpendicular to, that is, the film thickness. The surface of the glass substrate 52 is used as a reference for the film thickness of 0. As shown in FIG. 4A, the film thickness of the silver electrode 50 before processing is about 10 μm.

FIG. 4B shows the measurement result of the film thickness of the silver electrode 50 of FIG. The measurement is performed with the silver electrode 50 parallel to the y direction.
Went on. The horizontal axis of FIG. 4B represents the position in the y direction,
The vertical axis represents the film thickness. The surface of the glass substrate 52 is used as a reference for the film thickness of 0. The portion having a film thickness of 0 in the center of FIG. 4B is a processed portion. From FIG. 4B, it can be seen that the processed portion has an extremely sharp edge and only the processed portion is removed cleanly.

FIG. 5 is a diagram schematically showing the result of processing the central portion of the silver electrode 50 as shown in FIG. 3 by a laser repair device using a conventional pulse Q switch laser as a light source. The boundary between the processed part and the non-processed part of the silver electrode 50 is wavy, and the processing residues 54 are scattered in the processed part. Further, scattered matter is accumulated over a wide area around the processed portion, and a black color changing portion 56 is formed.

The laser beam in the conventional device and the laser beam in the device of the present embodiment have different pulse widths, and therefore have different power distributions as described in FIG. As a result, when a silver electrode with a film thickness of about 10 μm is processed by the conventional device, when the pulse energy is lowered, the electrode is not cut, and the periphery of the processed part is blackened by dust and the pulse energy is increased. Although the silver electrode can be removed, the glass substrate is also processed and cracks easily occur. On the other hand, the apparatus according to the present embodiment can perform the removal processing that forms sharp edges and has less scattering.

The preferred embodiments of the present invention have been described above with reference to the accompanying drawings, but it goes without saying that the present invention is not limited to such examples. It is obvious to those skilled in the art that various changes or modifications can be conceived within the scope of the technical idea described in the claims, and of course, the technical scope of the present invention is also applicable to them. Be understood to belong to.

[0033]

As described above in detail, according to the laser repair method and the laser repair apparatus of the present invention, by using the laser having the pulse width of 50 to 150 ns (nanosecond), the conventional apparatus can remove the laser beam. It makes it possible to cleanly remove difficult substances and fix the laser oscillator to enable laser transmission through an optical fiber.
Optical transmission using an optical fiber makes it possible to maintain a constant irradiation energy density on the machined surface even if the irradiation position changes. Furthermore, it is possible to form a laser beam having a desired beam diameter and cross-sectional shape according to the processing part, and observe the irradiation area of the laser light on the processing surface to perform processing while confirming the processing shape and processing state. You can

[Brief description of drawings]

FIG. 1 is a configuration diagram of a laser repair device according to an embodiment of the present invention.

FIG. 2 is a diagram showing a correlation between pulse width and power.

FIG. 3 is a partial top view of a silver electrode.

FIG. 4 (a) is a diagram showing the measurement result of the film thickness of the silver electrode in the x direction before processing, and FIG. 4 (b) is the measurement result of the film thickness of the silver electrode in the y direction after processing. FIG.

FIG. 5 is a diagram schematically showing a processing result by a conventional device.

[Explanation of symbols]

50 silver electrode 52 glass substrate 54 Processing residue 56 Black color change part 100 light sources 200 incident lens unit 202 optical fiber 204 Collimating lens unit 300 microscope 302a, 302b Dichroic mirror 302c half mirror 304 Light source for slit shape illumination 306 Beam shaping slit 308a, 308b relay lens 310 Total reflection mirror 312 Objective lens 314 Light source for epi-illumination 316 CCD camera for observation 400 tables 500 object to be processed

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Claims (5)

[Claims] 1. A laser repair method for repairing a defective portion of a wiring pattern by using a laser beam, which has a pulse width of 50 to 50.
A laser repair method characterized by using a laser beam of 150 ns. 2. A laser repair device for repairing a defective portion of a wiring pattern by using a laser beam, which has a pulse width of 50 to 50.
A laser repair device characterized by using a laser beam of 150 ns. 3. An optical fiber for guiding laser light from a laser light source, an incident optical system for guiding the laser light emitted from the laser light source to the optical fiber, and collimating light emitted from the optical fiber. The laser repair device according to claim 2, further comprising a collimating optical system. 4. A slit for shaping a beam diameter and a cross-sectional shape of the laser light into a desired shape, and an observing means for observing an irradiation region of the laser light on a surface to be processed. The laser repair apparatus according to claim 2 or 3. 5. The laser repair apparatus according to claim 2, wherein a continuously pumped Q-switched Nd: YAG laser is used as a laser light source of the laser light.