KR100789277B1 - Etching method of transparent conductive film - Google Patents

Abstract

An etching method of a transparent conductive film is provided to secure a predetermined machining line width and etch a transparent conductive film coated on the flat panel display substrate while preventing damage to a part except the transparent conductive film on the flat panel display substrate. In an etching method of a transparent conductive film(26), in which the transparent conductive film is etched in a desired pattern(29) by the laser beam while moving a laser beam(50) laterally and longitudinally on the transparent conductive film coated on a substrate, the etching method comprises: a generation step of generating a single laser beam; a splitting step of splitting the single laser beam into a plurality of laser beams(51,52); and an irradiation step of concentratively irradiating the laser beams onto a part to be etched.

Description

Etching method of transparent conductive film

1 is a cross-sectional view of a typical LCD substrate.

2 is a view for explaining an example of a conventional transparent conductive film etching method.

Figure 3 is a perspective view showing an example of a transparent conductive film etching apparatus for implementing the transparent conductive film etching method according to an embodiment of the present invention.

4 is a diagram for explaining irradiation of a transparent conductive film by defocusing a laser beam.

5 is a view for explaining the shape of the laser beam before and after passing through the cylindrical lens shown in FIG.

<Description of the symbols for the main parts of the drawings>

10 laser oscillator 20 LCD substrate

21: upper glass plate 22: lower glass plate

23: black matrix 24: color filter

25 common electrode 26 transparent conductive film

27 thin film transistor 28 pixel electrode

31: upper prism lens 32: lower prism lens

41: upper cylindrical lens 42: lower cylindrical lens

50: single laser beam 51: first laser beam

51a: cross section of first laser beam after passing through prism lens

51b: cross section of first laser beam after passage through upper cylindrical lens

51c: cross section of first laser beam after passage through lower cylindrical lens

52: second laser beam

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of etching a transparent conductive film, and in particular, by dividing a single laser beam into a plurality of laser beams and concentrating on the portions to be etched in the transparent conductive film, thereby forming a predetermined processing line width (a pattern on a transparent conductive film). The present invention relates to a transparent conductive film etching method capable of preventing damage to portions other than the transparent conductive film to be etched while securing the line width.

Recently, LCD (Liquid Crystal Display) substrates and PDP (Plasma Dislay Panel) substrates are mainly used as flat display substrates displaying image information on a screen. The LCD substrate has a smaller power consumption, a longer life, and a lower heat generation than a PDP substrate. In addition, since the pixels of the LCD substrate are smaller than those of the PDP substrate, the resolution of the LCD substrate is superior to that of the PDP substrate in a small screen, for example, a screen size of 50 inches or less. Due to these advantages, LCD substrates are utilized as flat panel display devices in many industrial products.

1 is a cross-sectional view of a general LCD substrate. Referring to FIG. 1, the LCD substrate 20 includes a color filter panel 20a in which color implementation elements are arranged, and a thin film transistor panel 20b for electrically driving the color implementation elements. 20a and the thin film transistor panel 20b face each other and are bonded to each other.

As for the said color filter panel 20a, the color filter 24 of red (R), green (G), and blue (B) is sequentially arranged in the matrix arrangement method below the upper glass plate 21. As shown in FIG. Between these color filters 24, a grid-like black matrix 23 is formed to prevent the mixed color from appearing among the above-mentioned colors. The common electrode 25 is formed on the entire surface of the color filter 24 and the black matrix 23. A transparent conductive film 26 made of indium tin oxide (ITO) material is coated on the color filter panel 20a.

In the thin film transistor panel 20b, the pixel electrode 28 is formed on the upper side of the lower glass plate 22 in a matrix arrangement. The pixel electrode 28 is connected to a thin film transistor 27 that applies an electric field signal to the pixel electrode 28.

The transparent conductive film 26 coated on the upper surface of the color filter panel 20a is etched in a predetermined pattern. 2 is a view for explaining an example of a conventional transparent conductive film etching method. Referring to FIG. 2, the laser beam 1 generated from the laser oscillator 10 is incident on the focusing lens 12 via the reflection mirror 11. The laser beam focused by the focusing lens 12 is irradiated onto the transparent conductive film 26 of the portion to be etched. In order to realize a predetermined processing line width, there is also a method of overlapping the laser beam several times while moving the laser beam 1 little by little in the lateral direction, but defocusing the laser beam 1 and reducing the laser output due to defocusing. In order to compensate for this, the laser output is increased to realize the desired processing line width in one machining. As shown in FIG. 2, when the focusing lens 12 is moved upward (the focusing lens before the movement is indicated by "12 '" and the focusing lens after the movement is indicated by "12"), the transparent conductive film The focal point (indicated by "3 '" in FIG. 2) formed in 26 is formed in the upper space of the transparent conductive film 26 (indicated by "3" in FIG. 2), and the laser beam 1 is defocused And the spot is enlarged and irradiated onto the transparent conductive film 26.

When the transparent conductive film coated on the LCD substrate is etched using a single laser beam as in the related art, it is difficult to etch only the transparent conductive film at a predetermined desired processing line width without damaging parts other than the transparent conductive film. . For example, when etching a line width of 80 μm or more by the progress of a single laser beam, if the laser beam is excessively defocused to enlarge the size of the spot of the laser beam, the energy per unit area of the laser beam spot decreases. Should increase the output of. On the other hand, since the energy distribution form of the cross-sectional area of the laser beam shows a Gaussian distribution form, the energy of the center portion of the cross-sectional area of the laser beam is higher than that of the edge portion. Therefore, the transparent conductive film is etched to have a predetermined processing line width, but the high energy at the center of the cross-sectional area of the laser beam damages the color filter and the black matrix formed under the upper glass plate of FIG. 2. have. However, when the output of the laser beam is lowered to such an extent that the color filter and the black matrix are not damaged, the transparent conductive film cannot be etched to have a predetermined processing line width.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problem, and in the flat panel display substrate, the transparent conductive film applied on the flat panel display substrate can be etched while securing a predetermined processing line width while preventing portions other than the transparent conductive film from being damaged. An object of the present invention is to provide an improved method for etching a transparent conductive film.

In order to achieve the above object, the transparent conductive film etching method of the present invention, in the transparent conductive film etching method for etching the transparent conductive film in a desired pattern by moving the laser beam vertically and horizontally to the transparent conductive film coated on the substrate. A generating step of generating a single laser beam; A dividing step of dividing the single laser beam into a plurality of laser beams; And irradiating the plurality of laser beams by concentrating them on a portion to be etched of the transparent conductive film.

In the transparent conductive film etching method according to the present invention, preferably, in the dividing step, the single laser beam is divided into two laser beams.

In the transparent conductive film etching method according to the present invention, preferably, the single laser beam is divided into two laser beams by two prism lenses arranged to be spaced apart by a predetermined distance in the vertical direction on the same axis.

In the method of etching the transparent conductive film according to the present invention, preferably, before irradiating the plurality of laser beams onto the transparent conductive film, deforming each of the plurality of laser beams from circular cross-section light to elliptical cross-section light. It further includes;

In the method of etching the transparent conductive film according to the present invention, preferably, each of the laser beams is an elliptical cross section in a circular cross-section light by two cylindrical lenses arranged to be spaced apart by a predetermined distance in the vertical direction on the same axis. Transform into light.

In the method of etching the transparent conductive film according to the present invention, preferably, in the irradiating step, the laser beam irradiated to the transparent conductive film is depressed to prevent the substrate from being damaged by the laser beam irradiated to the transparent conductive film. It focuses and irradiates the said transparent conductive film.

In the method of etching the transparent conductive film according to the present invention, preferably, the laser beam is defocused by forming a focus on the upper side of the transparent conductive film.

In the transparent conductive film etching method according to the present invention, Preferably, the laser beam has a wavelength in the range of 200nm to 400nm.

In the transparent conductive film etching method according to the present invention, Preferably, the laser beam has a wavelength of 355nm substantially.

In the method of etching the transparent conductive film according to the present invention, preferably, the substrate is an LCD substrate in which a color filter panel on which color implementation elements are arranged and a thin film transistor panel for electrically driving the color implementation elements are opposed to each other. The transparent conductive film is a thin film made of indium tin oxide (ITO) material coated on the color filter panel.

Hereinafter, a preferred embodiment of a transparent conductive film etching method according to the present invention will be described in detail with reference to the accompanying drawings.

3 is a perspective view showing an example of a transparent conductive film etching apparatus for implementing a transparent conductive film etching method according to an embodiment of the present invention, Figure 4 is a view for explaining the irradiation to the transparent conductive film by defocusing the laser beam 5 is a view for explaining the shape of the laser beam before and after passing through the cylindrical lens shown in FIG.

Referring to FIGS. 3 to 5, the transparent conductive film etching apparatus illustrated in FIG. 3 moves the laser beam 50 vertically and horizontally to the transparent conductive film 26 coated on a substrate, thereby irradiating the transparent conductive film 26. Is an apparatus for etching a desired pattern 29, comprising a laser oscillator 10, a reflection mirror 11, a laser beam splitting means, and a laser beam modifying means.

The laser oscillator 10 generates a laser beam which is an energy source for etching the transparent conductive film 26, and the laser beam 50 emitted from the laser oscillator 10 is a transparent conductive film 26 to be etched. It has a wavelength in the range of 200 nm to 400 nm in view of its absorption rate. In general, the use of a laser beam in the visible and infrared wavelength ranges exceeding 400 nm wavelength results in a transmittance of 80% or more on the transparent conductive film 26, for example, an ITO thin film, but in the ultraviolet wavelength range of 400 nm or less. The beam shows a low level of transmittance of 30% or less on the ITO thin film. Therefore, when using the laser beam 50 having a wavelength in the range of 200 nm to 400 nm, since the heat transferred by the laser beam 50 is absorbed more by the ITO thin film, the wavelength in the range of 200 nm to 400 nm It is effective to etch the ITO thin film by using the laser beam 50 having. In this embodiment, preferably, the transparent conductive film 26 is etched using a laser beam 50 having a wavelength of 355 nm, which is a third harmonic wave of a laser of a medium to which Neodymium (Nd 3+) ions are added. .

The laser beam dividing means divides a single laser beam 50 whose path of travel is adjusted through the reflection mirror 11 into a plurality of laser beams 51 and 52, and is predetermined on the same axis in the vertical direction. It consists of two prism lenses 31 and 32 arranged at a distance apart. The upper prism lens 31 and the lower prism lens 32 are disposed so as to face edges with each other, such that the single laser beam 50 incident through one surface of the upper prism lens 31 is the upper prism lens 31. And it is refracted and divided by the lower prism lens 32, and is emitted to the two laser beams 51, 52 through one surface of the lower prism lens 32. The upper prism lens 31 and the lower prism lens 32 are provided with adjustment means for adjusting respective positions and rotation angles, so that two laser beams are emitted through one surface of the lower prism lens 32. It is possible to adjust the size and relative position of the (51) (52) to the shape desired by the user.

The laser beam modifying means transforms a circular laser beam cross-section light into an elliptical laser beam cross-section light, which is disposed below the prism lenses 31 and 32 and is disposed at a predetermined distance in the vertical direction on the same axis. It consists of two cylindrical lenses 41 and 42 spaced apart. As illustrated in FIG. 2, the upper cylindrical lens 41 disposed on the upper side of the two cylindrical lenses is formed such that the convex portions of the upper surface thereof are convex along the x axis and are not curved along the y axis. It is. The lower cylindrical lens 42 disposed below the upper cylindrical lens 41 is disposed at an angle of 90 degrees with the upper cylindrical lens 41. That is, as shown in FIG. 2, the lower cylindrical lens 42 is arranged such that the convex portions of the upper surface thereof are convex along the y axis and are not bent along the x axis.

Since the convex portions of the upper cylindrical lens 41 are convexly formed along the x-axis, the laser beams 51 and 52 passing through the upper cylindrical lens 41 are focused and reduced in the x-axis direction. In the y-axis direction, it has the size of incident light without being focused. Similarly, since the convex portions of the lower cylindrical lens 42 are convexly formed along the y axis, the laser beams 951 and 52 passing through the lower cylindrical lens 42 are focused and reduced in the y axis direction. In the x-axis direction, the incident size is maintained without being focused. The upper cylindrical lens 41 and the lower cylindrical lens 42 are disposed at an angle of 90 degrees, and one cylindrical lens serves to condense the laser beam in one axial direction, whereby the upper cylindrical lens 41 and the lower cylindrical lens 41 are disposed. By adjusting the focal length of the cylindrical lens 42, the laser beam passing through the upper cylindrical lens 41 and the lower cylindrical lens 42 can be selectively focused or defocused in the desired direction in the x- or y-axis direction. have.

Hereinafter, a method of etching the transparent conductive film coated on the LCD substrate by using the transparent conductive film etching apparatus of FIG. 3 configured as described above will be described with reference to FIGS. 2 to 5.

As shown in FIG. 3, the laser oscillator 10 generates a laser beam 50 having a wavelength in the range of 200 nm to 400 nm, preferably a laser beam 50 having a wavelength of substantially 355 nm. . Reflective mirror 11 or the like so that the laser beam 50 can be incident to two prism lenses 31 and 32 and two cylindrical lenses 41 and 42 disposed on the LCD substrate 20. Through this, the path of the laser beam 50 is adjusted.

As shown in Fig. 4 (a) (b), the single laser beam 50 passes through the upper prism lens 31 and the lower prism lens 32, and then two laser beams 51 and 52. Is divided into Each of the two divided laser beams 51 and 52 is focused by the upper cylindrical lens 41 and the lower cylindrical lens 42.

In order to form a pattern 29 having a desired shape on the transparent conductive film 26, defocused laser beams 51 and 52 are irradiated onto the transparent conductive film 26. 4A shows the cylindrical lenses 41 and 42 arranged so that the focal points of the plurality of laser beams are formed on the transparent conductive film 26. As shown in Fig. 4 (b), if the upper cylindrical lens 41 at the position shown in Fig. 4 (a) is moved upward, and the lower cylindrical lens 42 is kept in its original position, x A laser beam defocused in the axial direction and focused in the y-axis direction can be implemented. On the contrary, if the upper cylindrical lens 41 maintains its original position and the lower cylindrical lens 42 is moved upward, it can defocus in the y-axis direction and focus the laser beam in the x-axis direction. have. By adjusting the positions of the upper cylindrical lens 41 and the lower cylindrical lens 42 in this way, it is possible to implement a laser beam defocused in any one axial direction.

When the transparent conductive film 26 is etched using the laser beams 51 and 52 focused on the focal point, the spots are small in size, so that the laser beams 51 and 52 are gradually cut in the horizontal direction in order to secure a predetermined processing line width. Repeat the process several times while moving the) to complete the desired line width. In addition, since the energy per unit area of the laser beams 51 and 52 focused on the focal point is considerable, a color filter formed under the upper glass plate 21 shown in FIG. 2 during the etching of the transparent conductive film 26. 23 and the black matrix 24 are damaged. As described above, the spot size of the laser beam is small to prevent a decrease in production yield due to repeated processing several times, and to prevent damage to portions other than the transparent conductive film 26 such as the color filter 23. (51) and (52) are defocused and used.

The laser beams 51 and 52 that have passed through the prism lenses 31 and 32 are transformed from circular cross-section light into elliptical cross-section light by the cylindrical lenses 41 and 42. Specifically, the laser beams 51 and 52 that have passed through the lower prism lens 32 maintain a circular cross-sectional light shape, as shown by 51a and 52a in FIG. 5. When the circular cross section light passes through the upper cylindrical lens 41, as illustrated in FIGS. 5B and 51B, the circular cross-section light is focused in the x-axis direction and maintains the size of the laser beam incident in the y-axis direction. It is transformed into an elliptical cross section light shape. That is, a short axis is formed in the x-axis direction, and is deformed into an elliptical cross-section light in which a long axis is formed in the y-axis direction. When the cross-section light of the ellipse passes through the lower cylindrical lens 42, as shown in FIGS. 5 and 5 and 51c, the light is focused in the y-axis direction and maintains the size of the laser beam incident in the x-axis direction. It is transformed into an elliptical cross section light shape. That is, a short axis is formed in the y-axis direction, and is deformed into the cross-sectional light of an ellipse whose long axis is formed in the x-axis direction.

The cylindrical lenses 41 and 42 may be used to transform circular cross-section light into elliptical cross-section light, and may be transmitted by changing vertical positions of the upper cylindrical lens 41 and the lower cylindrical lens 42. By adjusting the degree to which the laser beam is defocused, it is possible to enlarge the long axis or short axis of the elliptical cross-section light to a desired size.

In the present embodiment, the long axis is formed in the x-axis direction, and the short axis is formed in the y-axis direction of the end surfaces 51c and 52c of the laser beam transmitted through the cylindrical lenses 41 and 42. As shown in FIG. 5, the long axes of the divided two elliptical laser beams 51c and 52c are mutually etched so that the transparent conductive film 26 can be etched with a line width of 80 μm or more even with a single laser beam. Concentrate on the portion to be etched of the transparent conductive film 26 so as to be arranged side by side, and advance the laser beam in the short axis direction of the elliptical laser beams 51c and 52c.

Using the transparent conductive film etching method according to the present embodiment configured as described above, in order to secure a predetermined processing line width, a single laser beam is divided into a plurality of laser beams, and the width of the groove to be etched is one laser beam. The transparent conductive film is etched by concentrating the plurality of laser beams so as to be larger than the diameter. Therefore, it is possible to obtain an effect of realizing a predetermined processing line width even with a single laser beam.

Further, by dividing a single laser beam into a plurality of laser beams, the amount of energy held by the single laser beam is also divided by the number of laser beams to be divided. In the case of using a single laser beam, the laser output is excessive and the color filter formed under the upper glass plate is damaged, and it is impossible to realize a predetermined processing line width. However, as the laser beam is divided, the energy is also divided together, so that it is possible to obtain an effect of realizing a predetermined processing line width without damaging the color filter.

Although preferred embodiments and modifications have been described above, the method of etching the transparent conductive film according to the present invention is not limited to the examples described above, and the modifications or combinations thereof may be used within the scope not departing from the technical spirit of the present invention. Various types of transparent conductive film etching methods can be embodied.

In the method of etching the transparent conductive film of the present invention, a single laser beam is divided into a plurality of laser beams, and the plurality of laser beams are intensively irradiated onto the transparent conductive film, thereby providing a predetermined processing line width even with the progress of a single laser beam. It can be implemented, there is an effect of improving the production yield of the substrate.

In addition, due to the division of the laser beam, the amount of energy possessed by the laser beam is also divided so that other parts formed on the substrate other than the transparent conductive film, such as the color filter and the black matrix part, are not damaged in the process of etching the transparent conductive film. It does not work.

Claims (10)

In the transparent conductive film etching method of etching the transparent conductive film in a desired pattern by moving the laser beam vertically and horizontally to the transparent conductive film coated on the substrate, A generating step of generating a single laser beam; A dividing step of dividing the single laser beam into a plurality of laser beams; And irradiating the plurality of laser beams by focusing the plurality of laser beams on a portion to be etched in the transparent conductive film. The method of claim 1, In the dividing step, the single laser beam is divided into two laser beams. The method of claim 2, And the single laser beam is divided into two laser beams by two prism lenses arranged to be spaced apart by a predetermined distance in the vertical direction on the same axis. The method of claim 1, And converting each of the plurality of laser beams from circular cross-section light into elliptical cross-section light before irradiating the plurality of laser beams onto the transparent conductive film. The method of claim 4, wherein The laser beam is a transparent conductive film etching method, characterized in that by the two cylindrical lenses arranged on the same axis spaced apart by a predetermined distance from the circular cross-section light to the elliptical cross-section light. The method of claim 1, In the irradiating step, in order to prevent the substrate from being damaged by the laser beam irradiated to the transparent conductive film, defocusing the laser beam irradiated to the transparent conductive film, characterized in that for irradiating the transparent conductive film Transparent conductive film etching method. The method of claim 6, The laser beam is transparent conductive film etching method, characterized in that the focus is formed on the upper side of the transparent conductive film is defocused. The method of claim 1, The laser beam is transparent conductive film etching method, characterized in that having a wavelength in the range of 200nm to 400nm. The method of claim 8, The laser beam has a wavelength of 355nm substantially, the transparent conductive film etching method. The method of claim 1, The substrate is an LCD substrate in which a color filter panel in which color implementation elements are arranged and a thin film transistor panel for electrically driving the color implementation elements are opposed to each other. The transparent conductive film is a transparent conductive film etching method, characterized in that the thin film made of indium tin oxide (ITO) material applied on the color filter panel.

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