JP3858356B2 - Manufacturing method of color filter - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing a color filter for a liquid crystal display device.
[0002]
[Prior art]
Conventionally, when a pattern is formed on a substrate on which a photosensitive resist film is formed, exposure is performed intermittently. Specifically, for example, the substrate and the exposure mask are aligned via an exposure mask having a predetermined light-shielding pattern film on a continuous film-like substrate having a photosensitive resist coated on the surface. The pattern was formed by repeating the steps of performing collective exposure after stopping, moving the substrate again, aligning the position again, and performing collective exposure after stopping.
[0003]
However, in this method, time is required for each process such as loading of the substrate, alignment time, exposure operation, and unloading of the substrate. As a result, there is a problem that the processing capacity (throughput) per unit time is low. Therefore, when forming a stripe pattern of a color filter, a transfer sheet is used in which a color pattern is once formed on a continuous film-like substrate, and the color pattern is transferred to a final formation site such as a glass substrate. The high-efficiency pattern formation, which is the main purpose of the conventional pattern formation method, has not been sufficiently achieved.
[0004]
In addition, after forming a color pattern on a continuous film-like substrate, the color pattern is transferred to a final location such as a glass substrate. A black matrix for preventing transmission of excess light is formed in the peripheral frame portion of the display portion. Conventionally, the black matrix is formed by a layer of photosensitive resin or the like in which metal chromium, chromium oxide, or black resin is dispersed on a glass substrate, which is a final formation place, by a photolithography technique using a photomask. Is formed by patterning a film formed on the entire surface. Thereafter, a color pattern was transferred from the transfer sheet by the above-described method.
[0005]
However, in such a method, alignment between the glass substrate, which is the final formation location, and the transfer sheet is difficult because high accuracy is required, and so-called “white spots” are generated when misalignment occurs. In particular, in the case of a liquid crystal display device of a type using a backlight, the contrast is lowered and becomes very conspicuous, so that the product is completely defective. In addition, in such misalignment, white spots occur, but an abnormal overlap occurs between the color pattern and the black matrix, resulting in a large surface step. There is a problem that a gap is generated between the transfer sheet and the transfer sheet. For this reason, measures such as providing a planarizing layer are required.
[0006]
[Problems to be solved by the invention]
The present invention is a high-efficiency pattern formation in a pattern formation method using a transfer sheet, a positional shift due to the necessity of alignment between the glass substrate and the transfer sheet as described above, a problem of a step difference in the surface of the transfer sheet, etc. An object of the present invention is to provide a method for manufacturing a color filter that eliminates the above-mentioned problem.
[0007]
[Means for Solving the Problems]
In the present invention, a photosensitive colored resist film is formed on a continuous base material, and exposure is performed while continuously feeding the base material through a photomask having a stripe-shaped light shielding pattern thereon. After forming a desired colored stripe pattern repeatedly, a photosensitive black resist film is further applied and formed, and coloring is performed by exposing from the surface opposite to the film surface through a mask for exposing the peripheral frame pattern of the black matrix. A method of manufacturing a color filter, comprising: forming a black matrix layer in a gap between stripe patterns.
[0008]
Now, when forming a stripe pattern of a color filter used in a liquid crystal display device, a color pattern is once formed on a continuous film-like substrate, and the color pattern is transferred to a final formation place such as a glass substrate. Conventionally, when carrying out pattern formation methods using sheets, a continuous film-like substrate with a photosensitive resist film is used to increase the throughput per unit time (throughput) and realize highly efficient pattern formation. We have already proposed a method of forming a stripe pattern by pattern exposure in a continuous irradiation state.
[0009]
The continuous irradiation state here means that the exposure is basically performed while the active light source is continuously lit through a certain length (for example, one lot of base material) or a plurality of predetermined patterns. As a result, this means a method of continuously forming a pattern by photolithography.
[0010]
Further, the continuous base material here is a strip-like or film-like long material, and the material is 42 alloy (42% by weight of nickel, remaining iron), amber material (36% by weight of nickel, 0.36 of manganese). Synthetic resin film having both rigidity and heat resistance, such as rust-resistant metal in air, heat-resistant polyester film, polyimide film, polycarbonate film, such as 18-8 stainless steel (weight%, balance iron), 18-8 stainless steel . In the case of a synthetic resin, rigidity is an essential property derived from the fact that expansion and contraction when a substrate is conveyed is not preferred in the present invention.
[0011]
The photosensitive resist film is obtained by applying and drying a photosensitive resin with a uniform thickness on the upper surface of a substrate. As a coating method, a known method such as a roll coating method, a bar coating method, or a slit coating method is used. it can. Further, the application area does not need to be a full-surface coating, and a certain area may be applied intermittently or partially corresponding to the required area of a desired pattern such as a color filter. The photosensitive resist film may be obtained by dispersing and mixing colorants such as dyes and pigments. In this case, a colored pattern can be obtained simply by developing after exposure.
[0012]
The exposure mask has a light shielding film having a stripe pattern on the lower surface of the transparent glass. Needless to say, the exposure mask is installed so that the direction of the stripe pattern is parallel to the continuous conveyance direction of the substrate.
Irradiation light from the light source is irradiated from the gap of the stripe pattern of the exposure mask to the substrate being transported. The required exposure dose is 100 to 200 mJ / cm ² . This range is the standard sensitivity of existing photosensitive resists. Here, if the illuminance irradiated from the light source is 100 mW / cm ² on the substrate surface, an exposure amount of 100 to 200 mJ / cm ² is required for the substrate, and therefore the substrate is used for 1 to 2 seconds. Of irradiation time is required. It can be seen that when the length of the exposure mask stripe is 60 mm, the conveyance speed may be 30 to 60 mm / sec in order to pass the length in 1 to 2 seconds. That is, the speed per minute is 1.8 to 3.6 m / min. Actually, since the illuminance from the light source can be doubled to about 200 mW / cm ² , the conveyance speed can be 3.6 to 7.2 m / min. This is a throughput that is five times higher than that of the conventional batch exposure method.
[0013]
After the exposure, development processing is performed for patterning. When the photosensitive resist is a negative type, a portion not irradiated with light is dissolved and removed by the developer, and the irradiated region remains to form a stripe pattern.
[0014]
After that, a photosensitive black resist film is further formed on the continuous substrate on which the stripe pattern is formed, and the stripe pattern itself is made to function as a mask by exposing from the surface opposite to the film surface, and the black matrix is formed. Easy and highly accurate formation. At the same time, the black matrix of the pattern frame can be formed at the same time by performing exposure through the pattern exposure mask in the peripheral frame of the black matrix.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described with reference to the drawings shown in FIGS.
As shown in FIG. 3, the base material 1 is fed out from a feed reel 2 in which a base material 1 made of, for example, a 42 alloy metal film is wound in a coil shape, at a maximum constant speed that can be processed in an exposure process described later. First, the release layer 4 is applied to the entire surface of the substrate 1 with a uniform thickness by the coater 3a, and the release layer 4 is dried by the oven 6a.
[0016]
Next, a negative photosensitive resist film 5 in which a pigment is dispersed and mixed as a colorant is applied by the coater 3b to the entire surface of the substrate 1 with a uniform thickness, and the resist film 5 is dried by an oven 6b. After that, the base material 1 is guided by the non-touch roller 7 ′ and the normal roller 7, and swings in the lateral direction with respect to the traveling direction of the base material 1 with a mechanical accuracy of ± 3 μm per 240 mm feed length of the base material 1. The process proceeds to the exposure part X shown in FIG. 4 while being suppressed and ensuring linearity.
[0017]
In the exposure part X, the substrate 1 is opposed to the photomask 8 in which a stripe pattern having a line width of 300 μm and a pitch of 400 μm is formed in a range of width 320 mm and length 64 mm, and the gap between them is, for example, close exposure of about 100 μm. It is controlled to become.
[0018]
Immediately above the photomask 8 is an endless belt 9 made of a thin metal plate having a peripheral length equal to or an integral multiple of the mask pattern repetition period, leaving only the outer shape of the stripe pattern to be formed, and the pattern portion being an opening. Is installed and moves in synchronism with the conveying speed, direction and parallelism of the substrate 1 in strict synchronization. Incidentally, in the endless belt 9, in addition to the stripe pattern portion, an arbitrary pattern such as an alignment mark A and a product name can be formed as an opening portion. In this case, all the band-like areas through which the arbitrary pattern on the photomask 8 passes are set as openings. A light source 10 and a reflecting mirror 16 for efficiently using the light are positioned in the space inside the endless belt 9 and continuously generate ultraviolet light.
[0019]
In this embodiment, the illuminance irradiated from the light source is 120 mW / cm ² on the substrate surface, and the exposure dose is 150 mJ / min by transporting the substrate at a speed of about 3.1 m / min. An appropriate value of cm ² is obtained. In this case, since the vertical width of the color filter screen (width in the longitudinal direction of the base material) is about 20 cm, an exposure process of about 900 sheets per hour can be performed.
With the mechanism as described above, a colored stripe pattern having a line width of 100 μm and a pitch of 400 μm is exposed to the resist film 5 on the substrate 1 in the exposure portion X.
[0020]
Thereafter, the base material 1 having the resist film 5 subjected to pattern exposure is then directly advanced to the development process. That is, spray development is performed by spraying a developer from the surface of the substrate 1 from the nozzle 11, followed by a water washing step with pure water spray 12, a drying step with an air knife 13, and a post-baking step by movement in the hot plate 14. Then, the substrate 1 on which the colored stripe pattern is formed is wound around the take-up reel 15 with a tension of ² kg / mm ² .
[0021]
The above steps are repeated as many times as necessary for the number of colors of the stripe pattern while performing alignment by using the alignment mark A formed together with the stripe pattern of the already formed color.
[0022]
Thereafter, as shown in FIG. 5, a photosensitive black resist film 5b is further applied to the portion excluding the alignment mark A by a coater 3c on the continuous base material 1 on which the stripe pattern of each color is formed. Then, the resist film 5b is dried by an oven 6c. Next, as shown in FIG. 1, the alignment mark A and the alignment mark B on the photomask 8b are aligned with each other through a photomask 8b having a black matrix peripheral frame pattern from the surface opposite to the film surface. Then, the substrate 1 is stopped at the exposure part Y, or ultraviolet exposure is performed while moving the exposure part Y in synchronization with the moving speed of the substrate 1, and then again as shown in FIG. Spray development processing is performed by spraying a developer onto the surface of the substrate 1 from the nozzle 11, followed by a water washing process using pure water spray 12, a drying process using an air knife 13, and a post baking process using movement in the hot plate 14. Go through. Finally, the base material 1 on which the colored stripe pattern and the black matrix are formed is wound around the take-up reel 15.
[0023]
The transfer sheet as shown in FIG. 6 made by the above steps is pressure-bonded from the pattern forming surface onto a final substrate such as a glass substrate 17 as shown in FIG. Thus, the color stripe pattern and the black matrix can be collectively transferred and formed as a color filter.
[0024]
【The invention's effect】
By exposing the black matrix formation process from the back side through a pattern mask that mainly has a black matrix peripheral frame pattern pattern, the previously formed colored stripe pattern itself functions as a mask, and the stripe pattern of each color The black matrix in between can be formed very easily and with high accuracy, and the black matrix in the pattern peripheral frame can also be formed at the same time.
Thereby, there is no fear of misalignment between the colored stripe pattern and the black matrix. Therefore, in the case of a backlight type LCD, “white spots” that are very conspicuous on the screen do not occur. In addition, there is no level difference on the transfer sheet surface due to misalignment between the colored stripe pattern and the black matrix, and transfer can be performed without creating a gap even when an extra flattening layer is not provided when transferring to the final substrate. .
[0025]
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing one step of a production method of the present invention.
FIG. 2 is a cross-sectional view illustrating an example of a color filter according to the present invention.
FIG. 3 is an explanatory view showing an embodiment of the production method of the present invention.
FIG. 4 is a perspective view showing a main part of one step of the manufacturing method of the present invention.
FIG. 5 is an explanatory view showing an example of the production method of the present invention.
FIG. 6 is a cross-sectional view showing an example of a transfer sheet used in the production method of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Base material 2 Delivery reel 3 Coater 4 Release layer 5 Resist film 6 Oven 7 Roller 8 Photomask 9 Endless belt 10 Light source 11 Nozzle 12 Pure water spray 13 Air knife 14 Hot plate 15 Take-up reel 16 Reflective mirror 17 Glass substrate

Claims (1)

A photosensitive colored resist film is formed on a continuous substrate, and the substrate is continuously exposed through a photomask having a striped light-shielding pattern, and the exposure is repeated as many times as necessary. After forming the colored stripe pattern, a photosensitive black resist film is further applied and formed, and the gap between the colored stripe patterns is exposed from the surface opposite to the film surface through a mask for exposing the peripheral frame pattern of the black matrix. A method for producing a color filter, comprising: forming a black matrix layer on the substrate.

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