JP5239218B2 - Manufacturing method of color filter - Google Patents

Description

The present invention relates to a method for manufacturing a color liquid crystal display device (hereinafter referred to as LCD) filter, a method of manufacturing a color filter in particular according to the method of forming the transparent conductive film for a transparent electrode.

  The manufacturing process of a conventional LCD color filter will be described in order. The first step is a pattern formation step, in which an R pixel pattern, a G pixel pattern, and a B pixel pattern are formed in that order in the opening of the light shielding film pattern on one side of the transparent substrate.

  The pattern forming process is a known method, and a photolithographic method is generally used. In that process, a resist solution coating process using a photosensitive resin on a transparent substrate, a pattern transfer process to the resist, a development process for forming a resist pattern, or an etching process and a resist using a resist as a mask. It is formed by a film removal process. The materials, devices, etc. are well known and will not be described.

  Next, the second step is a step of forming a transparent electrode, in which a transparent electrode made of a transparent conductive film is formed on the surface of the R, G, B pixel pattern (hereinafter referred to as a colored layer). As the transparent conductive film, indium oxide or a mixed oxide (ITO) mainly composed of indium oxide and added with tin oxide is generally used. In addition, a technique of using zinc oxide ZnO as a transparent electrode instead of expensive indium has been proposed. In the method for forming the transparent conductive film, the inside of the sputtering tank is depressurized to a predetermined degree of vacuum, then Ar gas and oxygen gas are supplied, the sputtering target is charged, and the film is formed by DC magnetron sputtering or the like.

  In forming a transparent conductive film of a conventional color filter for LCD, it is common to form an ITO film using a single-wafer type in-line sputtering apparatus for forming a thin film. The single-wafer type in-line sputtering apparatus includes a first vacuum chamber capable of evacuating a transparent substrate having an organic film formed of a colored layer on an apparatus tray from atmospheric pressure to a predetermined medium vacuum pressure region, and a predetermined medium vacuum pressure. A second vacuum chamber that can be evacuated from a region to a predetermined high vacuum pressure region and capable of introducing an inert gas and an oxygen gas, and can be evacuated to the predetermined high vacuum pressure region and introduced an inert gas and an oxygen gas. However, a third vacuum chamber for forming a conductive thin film by maintaining the sputtering target at a high potential, and a second vacuum chamber capable of evacuating from a predetermined medium vacuum region to a predetermined high vacuum region and introducing an inert gas and an oxygen gas. It is an apparatus having a structure having a vacuum chamber divided into four vacuum chambers and a fifth vacuum chamber that can be evacuated to a predetermined medium vacuum pressure region that can be taken out to atmospheric pressure.

  The transparent substrate is placed on the apparatus tray, and the thin film formation pattern is fixed by using a metal mask or the like that has been molded, and then is inserted into the apparatus in order from the apparatus input side. Inside the device, the transparent substrate of the color filter moves from the first vacuum tank to the fifth vacuum tank from the second vacuum tank / third vacuum tank / fourth vacuum tank to form a transparent conductive thin film. The color filter base materials thus taken out are sequentially carried out of the apparatus from the apparatus carry-out side.

  The second vacuum chamber is a pre-environment vacuum chamber for the ITO film, and the high vacuum pressure region is generally 0.01 to 0.03 Pa. The third vacuum tank is an ITO film forming environment vacuum tank, and oxygen gas and an inert gas such as Ar gas are introduced into a vacuum layer exhausted to a high vacuum region near 0.001 to 0.01 Pa. However, it is common that the high vacuum pressure region is increased to a region near 0.1 to 1 Pa. In the ITO film forming environment vacuum chamber, a balanced DC magnetron sputtering target is charged with a high potential to form a transparent electrode of a conductive film by sputtering.

  In forming the transparent electrode, a conventional non-equilibrium sputtering apparatus is widely used. In a conventional non-equilibrium sputtering apparatus, the magnetic circuit part of sputtering is formed by a central magnetic pole and an external magnetic pole, and the magnetic field lines are adjusted so that the lines of magnetic force from both the central magnetic pole and the external magnetic pole are balanced. The sputtered film is formed in a closed state.

  3a-c are enlarged views of the sputtering portion of a conventional non-equilibrium sputtering apparatus. FIG. 3A is a perspective view of the magnetic circuit unit. The magnetic circuit unit 1 has a central magnetic pole 2 at the center, and an external magnetic pole 3 is formed outside the central magnetic pole 2 so as to surround the central magnetic pole 2. In the central magnetic pole 2, the upper side is the N pole, the lower surface is the S pole, and conversely, in the external magnetic pole 3, the upper side is the S pole, the lower surface is the N pole, and the strength of the magnetic field lines of both magnetic poles is adjusted to be the same. That is, it is a balanced type.

  FIG. 3b is a cross-sectional side view of the sputtering portion. An LCD color filter 10 with the R, G, B pixel pattern surface on the bottom is placed on the upper part of the figure, the magnetic circuit part 1 is placed on the lower part of the figure, and a target for the ITO film is directly above the magnetic circuit part 1. 4 is placed. As shown in the figure, the polarities of the central magnetic pole 2 and the external magnetic pole 3 are reversed, and the magnetic field lines are adjusted so that the magnetic lines of force generated from both the central magnetic pole 2 and the external magnetic pole 3 are balanced, and the magnetic field 5 is closed in a tunnel shape. It is the design which forms a sputtered film in a state. At the time of forming the sputtered film, sputtering gas supplied in vacuum, for example, argon gas, is ionized, Ar ions 31 collide with the target, and the sputtered particles 30 jump out of the target due to the collision energy, and the surface of the color filter 10 for LCD is surfaced. Deposit while diffusing.

  FIG. 3 c is a conceptual diagram for explaining how the sputtered particles 30 jumping out of the target are deposited while being diffused on the surface of the LCD color filter 10. In the path 1, the sputtered particles 30 travel straight in the vacuum space and scatter toward the LCD color filter 10. Next, in the path 2, it collides with the surface of the color filter 10 for LCD, deposits while diffusing the surface in the vicinity and bulk diffusing inside the formed ITO film, and forms the ITO film by sputtering.

  In a conventional non-equilibrium sputtering apparatus, the magnetic field lines generated from both the central magnetic pole 2 and the external magnetic pole 3 are adjusted so as to be balanced, and the sputtered film is formed with the magnetic field closed in a tunnel shape. There is a problem that the sputter particles 30 that travel straight in the vacuum space of the path 1 and scatter in the direction of the color filter 10 for the LCD have little energy, and therefore surface diffusion and bulk diffusion do not occur sufficiently.

  In the conventional non-equilibrium sputtering apparatus, the sputtered particles 30 have less energy, so that surface diffusion and bulk diffusion do not occur sufficiently. Therefore, the generated ITO film has many gaps or holes, and has a high density. There is a problem that the film quality is low, and therefore the film strength is low and the environmental resistance is weak.

  In addition, as for the shape of the ITO film, the step coverage with respect to the surface shape / step of the LCD color filter 10 is poor. For example, when the shape of the step portion is overhang, the ITO film is formed on the side surface (side wall portion) of the overhang portion. Is not formed, the ITO film is disconnected, and the transparent electrode has a problem of poor conduction.

  FIG. 4 is a side sectional view for explaining step coverage with respect to the surface shape and level difference of a conventional color filter. Since the surface diffusion and the bulk diffusion are not sufficiently generated on the side wall where the step portion 15 has an overhang shape, the film thickness becomes insufficient and a conduction failure may occur.

With respect to the problems of low film strength and low environmental resistance, the prior art has proposed a method of heating the LCD color filter 10 simultaneously with film formation. In the sputtering apparatus which is not non-equilibrium of the heating film formation method, a substrate heating apparatus and an auxiliary apparatus for obtaining temperature rising stability are necessary, and there is a problem that the apparatus operating rate is lowered due to an increase in temperature rising and cooling time.

  Next, the third step is an annealing step for heating the transparent electrode, which is allowed to stand for a predetermined time in a thermostatic bath at 200 to 240 degrees Celsius and imparts sufficient electro-optical characteristics. A color filter having a predetermined quality is manufactured through the above steps.

  In order to solve the problem that the surface diffusion and the bulk diffusion do not occur sufficiently, ion plating, bias sputtering, and RF / DC sputtering are proposed as conventional sputtering apparatus technologies. The ion plating method is not suitable for large-area film formation, and the bias sputtering method and the RF / DC sputtering method are more complicated and costly than the conventional non-equilibrium DC sputtering apparatus. There is.

The known literature is described below.
JP 2000-243160 A

The object of the present invention is to form a transparent conductive film with excellent film strength, environmental resistance, and step coverage to the surface step of the substrate even when sputtering is performed without heating or at a low temperature. it is to provide a method for manufacturing a filter.

In the invention according to claim 1 of the present invention, the shape of the light shielding layer and the stepped portion is overhang on the transparent substrate.
In the method of manufacturing a color filter, after sequentially forming the colored layer that becomes the side wall of the cathode , a target is placed above the colored pixel by using a DC magnetron sputtering method, and a transparent conductive film is formed on the colored layer. using the apparatus magnetic circuit is a non-equilibrium state more strong outer force than the central portion of, while introducing the inert gas and oxygen gas region of the high vacuum pressure in the vacuum pressure that boosts the 0.6Pa And forming a transparent conductive film.

  The invention according to claim 2 of the present invention is the method for producing a color filter according to claim 1, wherein the transparent conductive film is formed by an annealing process after being formed by an unheated sputtering method. .

  The invention according to claim 3 of the present invention is the method for producing a color filter according to claim 1 or 2, wherein the surface is smoothed by polishing before forming the transparent conductive film. is there.

  The invention according to claim 4 of the present invention is characterized in that a plasma treatment is performed as a pretreatment immediately before the formation of the transparent conductive film. It is.

  The invention according to claim 5 of the present invention is the color filter manufacturing method according to claim 4, wherein the plasma treatment uses atmospheric pressure plasma.

The invention according to claim 6 of the present invention is characterized in that the transparent conductive film is formed of indium oxide or a mixed oxide mainly composed of indium oxide. It is a manufacturing method of a filter.

The invention according to claim 7 of the present invention is characterized in that a transparent conductive film is formed of zinc oxide or a mixed oxide mainly composed of zinc oxide, according to any one of claims 1 to 5. It is a manufacturing method of a filter.

  According to the color filter manufacturing method of the present invention, when forming the transparent conductive film, the magnetic circuit portion is unbalanced, so that the extra magnetic field lines of the external magnetic pole are directed outward (toward the substrate), that is, a leakage magnetic field is formed. Then, a part of the plasma is extracted toward the substrate by the leakage magnetic field, and the energy of the sputtered particles 30 is increased by the ion assist, etc., and the surface diffusion and the bulk diffusion are sufficiently effective, and the transparent conductive film having a strong film quality. A membrane can be provided.

  According to the color filter manufacturing method of the present invention, when forming the transparent conductive film, the magnetic circuit portion is unbalanced, so that the extra magnetic field lines of the external magnetic pole are directed outward (toward the substrate), that is, a leakage magnetic field is formed. In addition, a part of the plasma is extracted toward the substrate by the leakage magnetic field, and ion diffusion or the like, surface diffusion or re-sputtering by ion assistance or the like is sufficiently effective, and step coverage for the surface shape / step difference of the color filter. Can be secured.

  The color filter of the present invention can reduce the film formation cost of the transparent electrode, can provide a transparent electrode transparent conductive film excellent in film strength and environmental resistance, and has excellent step coverage to the surface step of the substrate. A membrane can be provided.

  The color filter of the present invention and the manufacturing method thereof will be described below based on an embodiment in which an ITO film is used as a transparent conductive film.

  FIG. 1a is an enlarged cross-sectional side view of the sputtering portion of the non-equilibrium sputtering apparatus of the present invention. In FIG. 1a, the magnetic circuit portion 1 is deliberately formed in a non-equilibrium state in which the magnetic force of the central magnetic pole 2 is weaker than that of the external magnetic pole 3, so that the magnetic field lines emitted from the external magnetic pole 3 are conventional. In the same manner as above, a tunnel is formed toward the central magnetic pole, and the extra magnetic field lines become a leakage magnetic field 6 and travel outward and reach the substrate. In FIG. 1 a, an environment is formed in which a magnetic field 5 that closes in a tunnel shape and a leakage magnetic field 6 that reaches the substrate coexist.

  An LCD color filter 10 with a colored layer on the bottom is placed on the top of the figure, a magnetic circuit unit 1 is placed on the bottom of the figure, and an ITO film alloy target 4 is placed directly on the magnetic circuit part 1. Yes. As shown in the figure, the polarities of the central magnetic pole 2 and the external magnetic pole 3 are reversed, and the magnetic lines of force generated from both the central magnetic pole 2 and the external magnetic pole 3 are adjusted so as to be unbalanced and closed in a tunnel shape. The sputtered film is formed in an environment where the magnetic field 5 and the leakage magnetic field 6 reaching the substrate are mixed. During the formation of the sputtered film, a sputtering gas supplied in a vacuum, for example, argon gas, is ionized, the Ar ions 31 collide with the target, and the collision energy causes the sputtered particles 30 to jump out of the target, moving toward the substrate and leaking magnetic fields. 6 is further accelerated, accumulates sufficient energy, and deposits on the surface of the LCD color filter 10 while being surface diffused.

FIG. 1 b is a perspective view of the magnetic circuit unit. The magnetic circuit unit 1 has a central magnetic pole 2 at the center, and an external magnetic pole 3 is formed outside the central magnetic pole 2 so as to surround the central magnetic pole 2. In the central magnetic pole 2, the upper side is the N pole, and the lower surface is the S pole. Conversely, in the external magnetic pole 3, the upper side is the S pole, and the lower surface is the N pole. That is, a non-equilibrium type is assumed. In the case of the present invention, the magnetic force of the central magnetic pole 2 is weaker than that of the external magnetic pole 3 and is in an unbalanced state.

  FIG. 1 c is a conceptual diagram for explaining how the sputtered particles 30 jumping out of the target are deposited while diffusing on the surface of the LCD color filter 10. In the path 1, it is further accelerated by the influence of the leakage magnetic field 6, and the sputtered particles 30 travel straight through the vacuum space at an ultra high speed and are scattered toward the LCD color filter 10. Next, in the path 2, the sputtered particles 30 storing sufficient energy collide with the surface of the color filter 10 for LCD, and form a uniform film while diffusing in the vicinity thereof, and within the existing ITO film. A film having a stable quality is deposited while bulk diffusion is performed, and an ITO film is formed by sputtering. At the same time, the Ar ions 31 are accelerated by the influence of the leakage magnetic field 6 and collide with the film surface. The Ar ions 31 travel straight through the vacuum space at an ultra-high speed, and the Ar ions 31 with sufficient energy collide with the surface of the existing ITO film, forming an ITO film in the vicinity thereof with uniform film quality.

  FIG. 2A is a side sectional view for explaining step coverage with respect to the surface shape and level difference of the color filter of the present invention. Since the surface diffusion and the bulk diffusion are sufficiently generated on the side wall where the step portion 15 has an overhang shape, the film thickness is sufficient and there is no occurrence of poor conduction.

  FIG. 2 b is an explanatory diagram of the film formation process of the transparent electrode film. In the step portion 15, the influence of the leakage magnetic field 6 is effective in the vicinity of the substrate 10, and the sputtered particles 30 scattered from the direction of the target 4 are sufficiently accelerated to collide with the surface of the ITO film 14 and in the vicinity of the surface. Then, the surface diffusion is repeated, and the sputtered particles 30 are dispersed in the vertical and horizontal directions to form a uniform film thickness. For example, the step portion 15 forms a uniform film thickness on the side wall side. On the other hand, the scattered Ar ions 31 are sufficiently accelerated by the leakage magnetic field 6 and collide with the surface of the ITO film 14 to release the sputtered particles 30 again and reattach to the surface of the nearby ITO film 14, for example, the side wall surface. , Increase the film thickness of the sidewall surface. With the above effects, step coverage with respect to the surface shape and level difference of the color filter can be ensured.

  Below, it demonstrates according to the specific Example of the manufacturing method of the color filter of this invention. Example 1 is a method for manufacturing a color filter, and Example 2 is an example in which an ITO film is formed on the color filter of Example 1.

  The transparent substrate for color filter of Example 1 is glass, and the size used was 680 mm × 880 mm × 0.7 mm. First, on a transparent substrate for a color filter having a thickness of 0.7 mm, a light shielding film having a thickness of 0.1 μm is formed by a known method, for example, by vapor deposition of metal chromium, and then a metal chromium lattice pattern is formed by a photo process method. A light shielding film layer 11 was formed (see FIG. 2A).

  Subsequently, the mask for color filters of this invention was created. The mask substrate was formed of QZ and the light shielding film was formed of a single layer film of Cr. The thickness of the single layer film of Cr is 1000 mm. Its width is 12 μm.

The pigment-dispersed resin layer is formed by applying the pigment-dispersed resin resist uniformly to the entire surface of the color filter substrate 10 with the light-shielding film layer 11 having a lattice pattern by spin coating. Then, the resist was pre-baked by heating at 70 ° C. for 20 minutes. The pigment-dispersed resin resist used was CR-2000 (product number, manufactured by Fuji Hunt Co., Ltd.). Under exposure light irradiation processing conditions, UV exposure was performed using a color filter mask under an exposure amount of 180 mJ / cm ² . Next, after developing using a dedicated developer, the resist was subjected to a post-baking process in which the resist was heated at a temperature of 230 ° C. for 20 minutes to form the colored layer 12 of the R pixel.

Next, a colored layer 13 of G pixels was formed. The pigment-dispersed resin resist was uniformly applied to the entire surface of the color filter substrate 10 at a thickness of 1.7 μm by spin coating, and then the resist was pre-baked by heating at a temperature of 70 ° C. for 20 minutes. . CG-2000 (product number, manufactured by Fuji Hunt Co., Ltd.) was used as the pigment dispersion resin resist. Under exposure light irradiation processing conditions, UV exposure was performed using a color filter mask under an exposure amount of 180 mJ / cm ² . Next, after developing using a dedicated developer, the resist was subjected to a post-baking process in which the resist was heated at a temperature of 230 ° C. for 20 minutes to form a colored layer 13 of G pixels.

Next, a colored layer of the B pixel was formed. The pigment-dispersed resin resist was uniformly applied to the entire surface of the color filter substrate 10 with a thickness of 1.3 μm by spin coating, and then pre-baked by heating the resist at a temperature of 70 ° C. for 20 minutes. . CB-2000 (product number, manufactured by Fuji Hunt Co., Ltd.) was used as the pigment dispersion resin resist. Under exposure light irradiation processing conditions, UV exposure was performed using a color filter mask under an exposure amount of 180 mJ / cm ² . Next, after developing using a dedicated developer, the resist was subjected to post-baking for 20 minutes at a temperature of 230 ° C. to form a colored layer of B pixels. As described above, the color filter substrate 10 partitioned and formed the light shielding film layer 11 with a lattice and the colored layer of RGB pixels.

  Next, Example 2 of the present invention shows an example in which the ITO film forming process is performed on the color filter of Example 1 using a single-wafer type in-line sputtering apparatus.

  The used apparatus is a single-wafer type in-line sputtering apparatus, and is composed of a first vacuum chamber / second vacuum chamber / third vacuum chamber / fourth vacuum chamber / fifth vacuum chamber. First, the color filter base material was placed on the apparatus tray and fixed using a metal mask or the like, and then was sequentially introduced into the apparatus from the apparatus input side. The transparent substrate for the color filter is glass, and the size is 680 mm × 880 mm × 0.7 mm, and the color filter of Example 1 in which an organic film composed of colored portions having the same pattern is formed is used.

  In the apparatus, the color filter formed with the transparent conductive film moves from the first vacuum tank to the fifth vacuum tank through the second vacuum tank / third vacuum tank / fourth vacuum tank, and from the apparatus carry-out side. They were taken out of the equipment in order. The second vacuum chamber was a pre-formation environment vacuum chamber, and after the transparent substrate on the apparatus tray was moved to the pre-formation environment vacuum chamber, the vacuum pressure was evacuated to 0.007 Pa.

  The third vacuum chamber is a forming environment vacuum chamber, and the high vacuum pressure region was increased to a region near 0.6 Pa while introducing an inert gas and an oxygen gas such as Ar gas into the high vacuum layer. Under vacuum pressure, a plasma state was formed using the non-equilibrium sputtering manufacturing conditions of the present invention, the film thickness was set to 1400 mm, and sputtering was performed to form an ITO film with a sheet resistance of 20Ω / □. .

  The non-equilibrium sputtering manufacturing condition is that the ratio of the magnetic force between the external magnetic pole and the central magnetic field of the magnetic circuit portion of the sputtering cathode (the magnetic force of the external magnetic pole / the magnetic force of the central magnetic field) is 1.3 or more. Then, it was set as 1.3, and it was set as the manufacturing condition of sputtering made into non-equilibrium.

  In the third vacuum chamber of the forming environment vacuum chamber, the film was formed in an environment where a non-equilibrium leakage magnetic field was formed using the conditions for forming the transparent conductive film of the present invention. An ITO film was formed on the color filter substrate at a substrate feed rate of 600 mm / min.

  Next, in the color filter formed with the ITO film, the annealing step for heating to the transparent electrode was omitted. Next, the formed ITO film was quality tested. As a result, the quality of the ITO film is a dense film quality with few voids, that is, a film quality with good film strength and environmental resistance, and in the visual evaluation of the surface step portion, the step coverage is improved, that is, the film formation on the side wall thereof. Thickness was sufficiently formed.

  In addition, the same effect was acquired even if it formed the transparent conductive film with the manufacturing method of the color filter of this invention with zinc oxide or mixed oxide which has zinc oxide as a main body instead of ITO film | membrane.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory view of a sputtering portion of a non-equilibrium sputtering apparatus according to the present invention, where a is a side sectional view of the sputtering portion, b is a perspective view of a magnetic circuit portion, and c is a color for an LCD. The process until deposition on the surface of the filter 10 is shown. It is a sectional side view. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side sectional view for explaining step coverage with respect to the surface shape and level difference of a color filter of the present invention, wherein a is a color filter for LCD, and b is an explanatory view of a film forming process of the transparent electrode film. FIG. 5 is an enlarged view of a sputtering portion of a conventional non-equilibrium sputtering apparatus, where a is a perspective view of a magnetic circuit portion, b is a side sectional view of the sputtering portion, and c is a color filter for LCD. FIG. It is side sectional drawing explaining the step coverage with respect to the surface shape and level | step difference of the conventional color filter.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Magnetic circuit part 2 ... Center magnetic pole 3 ... External magnetic pole 4 ... Target 5 ... Magnetic field 6 ... Leakage magnetic field 10 ... Substrate, (for LCD) Color filter 11 ... Light shielding film 12 ... Colored layer 13 ... Colored layer 14 ... ITO film, Transparent electrode 15 ... Stepped portion 30 ... Sputtered particles 31 ... Ar ions

Claims (7)

After sequentially forming a light-shielding layer on the transparent substrate and a colored layer having a stepped portion that becomes an overhanging side wall , a target is placed on the colored layer by using a DC magnetron sputtering method to place a target on the colored pixel. In a method of manufacturing a color filter for forming a transparent conductive film, a high vacuum is applied while introducing an inert gas and an oxygen gas using a device in which the magnetic circuit of the cathode is in a non-equilibrium state where the magnetic force outside the center is stronger than the center. method of manufacturing a color filter, which comprises forming a transparent conductive film by a vacuum pressure that boosts the region of pressure 0.6 Pa.   The method for producing a color filter according to claim 1, wherein the transparent conductive film is formed by an annealing process after being formed by an unheated sputtering method.   The method for producing a color filter according to claim 1, wherein the surface is smoothed by polishing before forming the transparent conductive film.   The method for producing a color filter according to claim 1, wherein a plasma treatment is performed as a pretreatment immediately before forming the transparent conductive film.   The method for manufacturing a color filter according to claim 4, wherein the plasma treatment uses atmospheric pressure plasma.   6. The method for producing a color filter according to claim 1, wherein the transparent conductive film is formed of indium oxide or a mixed oxide mainly composed of indium oxide.   6. The method for producing a color filter according to claim 1, wherein the transparent conductive film is formed of zinc oxide or a mixed oxide mainly composed of zinc oxide.

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