JP2010091607A - Substrate for alignment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a substrate for alignment, which achieves a position detection method for an alignment mark part capable of detecting the position of an alignment mark formed at the first colored layer without exposing the alignment mark formed at the first colored layer and without requiring a step of making the alignment mark formed at the first colored layer be easily viewed, in a method for producing a color filter-forming substrate forming a columnar spacer or a columnar spacer and a projection having a liquid crystal alignment function simultaneously with a step of forming a color filter composed of a colored layer. <P>SOLUTION: The alignment mark part is provided with: a mark composed of a colored layer arranged at one side of a transparent substrate; and one colored resin layer covering the whole of the mark region and arranged so as to be raised along the mark shape. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an alignment substrate having an alignment mark portion for alignment on one surface of a transparent substrate, and more particularly to a substrate for producing a color filter forming substrate for a liquid crystal display panel.

In recent years, progress toward an information society has been remarkable, and the use of display devices has been diversified, and various display devices have been developed and put into practical use.
In particular, liquid crystal display devices have been widely used in place of CRT (Cathode-Ray Tube, CRT).
In a liquid crystal panel for color display for a liquid crystal display device, a TFT substrate (TFT; Thin Film Transistor) and a color filter forming substrate (also referred to as a counter substrate) are opposed to each other, and the liquid crystal is sealed between the substrates. In addition, a structure in which a deflection plate is arranged outside the TFT substrate and the color filter forming substrate and a backlight part is arranged outside the TFT substrate, and the light from the backlight part is a color layer composed of colored layers of each color. Light that passes through a filter (hereinafter also referred to as CF) is displayed, but light that passes through a color filter formed of a colored layer of each color is on-off controlled for each pixel using a liquid crystal as a switching element.
As a method of controlling the liquid crystal, a method in which the alignment direction of the liquid crystal is rotated in a plane perpendicular to the substrate by a vertical electric field perpendicular to each substrate (also referred to as a vertical electric field method), and a lateral direction parallel to the substrate are used. There is a method of rotating in a plane parallel to the substrate by an electric field (also referred to as a transverse electric field method).
A typical example of the vertical electric field method is a TN method (Twisted Nematic mode), and the horizontal electric field method is known as an IPS (In-Plane Switching) method.
Usually, in the case of the TN system or the like, such an electric field is controlled by a control electrode made of a transparent conductive film (usually ITO film to tin-doped indium oxide) disposed on both substrates. In the case of the IPS method (lateral electric field method), the control electrode of the transparent conductive film (ITO film) disposed on the TFT substrate is used.
Recently, in the vertical electric field method, in order to control the viewing angle well, a liquid crystal alignment function protrusion has been provided on the color filter forming substrate.

Conventionally, as a mask for forming a TFT circuit or a color filter, the entire picture portion is formed by a plurality of graphic patterns made of a light-shielding film that substantially shields exposure light during transfer on one surface of a transparent substrate. Recently, in order to shorten the manufacturing process of a liquid crystal display panel, a light-shielding film that shields exposure light at the time of transfer on one surface of the transparent substrate, and the exposure light are used. A semi-transparent halftone film is patterned and disposed, and a light-shielding region provided with a light-shielding film, a halftone region provided with a halftone film without a light-shielding film, and a light-shielding film And a transparent area in which neither of the halftone films exists, a gradation mask provided (see Japanese Patent Application Laid-Open No. 2007-188069) and a fine slit below the resolution limit are arranged to adjust the exposure amount. Use of the slit mask (see JP 2002-196474) having fine slits has come to be performed.
For example, a columnar spacer (also referred to simply as a column) and a liquid crystal alignment function for controlling the interval for holding the liquid crystal of a liquid crystal panel in a color filter forming substrate for a liquid crystal display device by performing batch exposure using a gradation mask The protrusions can be formed simultaneously with the process of forming a color filter composed of a colored layer. (See JP 2005-84366 A)
In order to fabricate a gradation mask, for example, a dedicated mask blank in which a translucent film and a light shielding film are laminated on a transparent substrate may be used, and mask pattern plate-making may be performed. This is advantageous in that it is not necessary to arrange fine slits unlike a slit mask.
In such a gradation mask, the resist film thickness after development can be controlled in two stages by controlling the amount of transmitted light according to regions having different transmittances.
JP 2007-188069 A JP 2002-196474 A JP 2005-84366 A

As described above, recently, the process of manufacturing a liquid crystal display panel has been shortened, and columnar spacers, or columnar spacers and liquid crystal alignment function protrusions can be formed simultaneously with the process of forming a color filter composed of a colored layer. Has come to be done.
However, usually, the alignment mark is formed by the first colored layer, and the second and subsequent colored layers are formed in accordance with the mark, but the resin for forming the second and subsequent colored layers One colored layer covers the alignment mark made up of the first colored layer, but the alignment mark made up of the first colored layer in this state cannot be recognized by the current proximity exposure machine. .
For example, in a TN type color filter forming substrate composed of colored layers of resin BM to R, G, and B, an ITO film, and columns in order from the transparent substrate side, the columns are formed of R, G, In the case of forming by laminating the colored layers of B, the colored layers of R, G, and B are formed in this order as a first colored layer, a second colored layer, and a third colored layer, respectively. When forming, since the alignment mark is formed by the first colored layer (R colored layer), the alignment portion in the second and subsequent G and B colored layer forming steps and the BM forming step is 2 The resin colored layer 1 for forming the colored layers after the first layer covers the alignment mark made of the R colored layer. In the current proximity exposure machine, the alignment mark made of the R colored layer is used. Cannot be recognized.
For this reason, alignment is performed by forming the second and subsequent colored layers so that the alignment mark formed by the first colored layer is exposed. (See Japanese Patent Application No. 2008-008024)
In addition, alignment was performed by forming a BM film in a state where the ITO film was applied on the first colored layer. (See Japanese Patent Application No. 2008-011848)
At the time of these alignments, for example, the alignment mark portion is illuminated by ring illumination, and the CCD area sensor is used as an image sensor and the image is taken by the imaging means.
Japanese Patent Application No. 2008-008024 However, in the case of such an alignment method, the alignment mark formed by the first colored layer is exposed or the alignment mark formed by the first colored layer is easy to see. This process is necessary and takes time and is a problem in terms of productivity and yield.

As described above, recently, the process of manufacturing a liquid crystal display panel has been shortened, and columnar spacers, or columnar spacers and liquid crystal alignment function protrusions can be formed simultaneously with the process of forming a color filter composed of a colored layer. Has come to be done.
At that time, alignment is performed by forming the second and subsequent colored layers so that the alignment mark formed by the first colored layer is exposed, or ITO is formed on the first colored layer. In the state where the film is applied, the alignment method is performed in which the alignment is performed by forming the BM film. However, the alignment mark formed by the first colored layer is exposed or the first layer is exposed. A process for making the alignment mark formed of the colored layer easy to see is necessary, which is time-consuming and demanded in terms of productivity and yield.
The present invention is corresponding to this, and in the method for producing a color filter forming substrate, a columnar spacer or a columnar spacer and a liquid crystal alignment function protrusion are formed simultaneously with the step of forming a color filter comprising a colored layer. It is formed with the first colored layer without exposing the alignment mark formed with the colored layer of the eye or making the alignment mark formed with the first colored layer easy to see. It is intended to provide an alignment substrate that can detect the position of the alignment mark to be detected and enables a method for detecting the position of the alignment mark.

The alignment substrate of the present invention is an alignment substrate provided with an alignment mark portion for alignment on one surface of a transparent substrate, and the alignment mark portion is a colored layer disposed on one surface of the transparent substrate. And a colored resin layer that covers the entire mark region and is arranged so as to rise along the shape of the mark.
When the average inclination of the taper portion (also referred to as an edge portion) of the cross section across the width of the mark made of the colored layer in the alignment mark portion is θ, the value of tan θ Is 0.028 or more.
And any one of the above-mentioned alignment substrates, which is a substrate for producing a color filter forming substrate, and the alignment mark portion is used for patterning a colored layer in producing a color filter forming substrate. The color filter forming substrate has a color filter portion of each color composed of a colored layer of each color and a black matrix portion (also referred to as a BM portion) composed of a colored layer on one surface of the transparent substrate. A column portion (also referred to as a spacer) is formed of a colored layer for forming each color filter portion or black matrix portion, and an ITO layer is disposed on each color filter portion. And a color filter forming substrate.
Here, as shown in FIG. 3A, the cross section of the alignment mark portion across the width of the mark made of the colored layer is flat at the top 22a of the raised portion along the shape of the mark. It is assumed that the surface portion 22c is flat and a tapered portion (also referred to as an edge portion) 22b extending from the end of the top portion 22a to the surface portion 22c is formed with an inclination.
In this case, the average inclination is roughly the rising portion where the bottom surface of the taper portion (edge portion) 22b has a gentle slope when the surface shape of the cross section of the alignment mark portion is as shown in FIG. The average gradient of the region excluding the part where the gradient near the apex is gentle.
Further, the alignment mark portion here is based on the premise that the alignment mark portion is for detecting the position of the alignment mark portion by image processing from an image obtained by photographing the region with specular reflection illumination (epi-illumination illumination). .

(Function)
The substrate for alignment of the present invention is formed in such a configuration, so that a columnar spacer or a columnar spacer or a liquid crystal alignment function protrusion is formed at the same time as a color filter forming process comprising a colored layer. In the method for manufacturing the substrate, the alignment mark formed by the first colored layer is not exposed, and a process for making the alignment mark formed by the first colored layer easy to see is not required. It is possible to provide an alignment substrate that enables a position detection method of an alignment mark part that can detect the position of an alignment mark formed by the colored layer.
An alignment mark portion comprising a mark made of a colored layer disposed on one surface of a transparent substrate, and a colored resin layer that covers the entire mark area and is arranged so as to rise along the shape of the mark. It is assumed that the position of the alignment mark portion can be detected by image processing from an image obtained by photographing the area with specular reflection illumination (epi-illumination illumination), and thus the mark position can be detected.
Specifically, the alignment mark part is for detecting the position of the alignment mark part by image processing from an image obtained by photographing the region with specular reflection illumination (epi-illumination illumination). This is achieved by comprising a mark composed of a colored layer disposed on one surface and a colored resin layer disposed so as to cover the entire mark region and rise along the shape of the mark. .
Specifically, in the present invention, if the surface of the alignment mark portion is photographed and its shape can be sufficiently recognized, the center position of the mark made of a colored layer (also simply referred to as the mark position) is the center position of the photographed alignment mark portion. Based on the recognition that it corresponds to the above, it was found that the shape of the alignment mark part can be fully recognized by photographing with regular reflection illumination (epi-illumination).
In particular, when the average inclination of the taper portion (edge portion) of the cross section across the width of the mark made of the colored layer in the alignment mark portion is θ, it can be well recognized at a practical level.
The shape of the tapered portion (22b in FIG. 3) that swells along the shape of the mark of the alignment mark portion is a shape that varies at each location, and depending on the average inclination value of the shape of the tapered portion, The light illuminating the uneven portion is scattered not in a fixed direction, and a part of the light enters the CCD area sensor via the lens system of the image pickup device, and the amount of light entering the CCD area sensor increases. ) And the bottom surface portion (22c in FIG. 3) of the tapered portion (edge).
In order to fully recognize the tapered portion, when the gradation of luminance captured by the CCD area sensor of the imaging apparatus is set to 256 gradations from 0 to 255, the luminance of the tapered portion that becomes dark when photographing is increased and becomes brighter. Although it is calculated | required in a practical level that the brightness | luminance difference with the top part of an alignment mark part or the bottom surface part of a taper part is calculated | required in a practical level, a brightness | luminance difference is 10 or more when the value of said tan (theta) is 0.028 or more. It means that it can be.
This is particularly effective when the position of the alignment mark portion is detected during patterning of the colored layer in the production of the color filter forming substrate.
As a result, the conventional alignment mark formed by the first colored layer can be exposed, or the process for making the alignment mark formed by the first colored layer easy to see can be eliminated. .
This is effective when the alignment substrate is a substrate for producing a color filter forming substrate, and the alignment mark portion is used for patterning a colored layer in the production of the color filter forming substrate.
The color filter forming substrate has, on one surface of a transparent substrate, a color filter portion of each color composed of a colored layer of each color, and a BM composed of a colored layer, and a column portion (also referred to as a spacer) is provided for each color filter portion or BM portion. In the case of a color filter forming substrate for a liquid crystal display panel such as a TN method (Twisted Nematic mode), which is formed of a colored layer for forming a color filter, and an ITO layer is disposed on the color filter portion of each color. Is a method for producing a color filter forming substrate in which a columnar spacer, or a columnar spacer and a liquid crystal alignment function protrusion are formed simultaneously with a color filter forming step comprising a colored layer, and is formed with a first colored layer. It does not require a process to expose the alignment mark or to make the alignment mark formed by the first colored layer easy to see. Preparation of color filter formation substrate is possible.
In the pattern exposure process of color filter manufacturing, by applying incident light to the substrate and recognizing the colored alignment mark shape under the various resist layers, it is possible to form a pattern with colored laminated columns and reduce the number of TN product manufacturing processes. It can be realized and is particularly effective.

As described above, the alignment substrate according to the present invention is arranged so as to cover the entire mark area, and to rise along the shape of the mark, with the mark made of the colored layer disposed on one surface of the transparent substrate. With respect to the alignment mark portion consisting of one colored resin layer, the position of the alignment mark portion can be detected by image processing from an image obtained by photographing the region with specular reflection illumination (epi-illumination illumination). The mark position can be detected.
Then, by using the alignment substrate of the present invention, as a result, a columnar spacer or a columnar spacer or a columnar spacer and a liquid crystal alignment function protrusion are formed simultaneously with the process of forming a color filter comprising a colored layer. In this manufacturing method, the alignment mark formed by the first colored layer is exposed, and a step for making the alignment mark formed by the first colored layer easy to see is not required. It has become possible to provide a method for detecting the position of the alignment mark part that can detect the position of the alignment mark formed by the colored layer of the eye.

Embodiments of the present invention will be described with reference to the drawings.
FIG. 1A is a schematic cross-sectional view of a first example of an embodiment of an alignment substrate of the present invention, and FIG. 1B is an embodiment of the alignment substrate of the present invention. FIG. 1C is a diagram showing a schematic sectional view of the second example of the embodiment of the alignment substrate of the present invention, and FIG. 1D is a diagram showing a schematic sectional view of the second example. ) Is a diagram illustrating an example of the arrangement of pixels on the color filter forming substrate, and FIGS. 2A to 2H are FIGS. 1A, 1B, and 1C. FIGS. 3A and 3B are cross-sectional views showing manufacturing steps of the first to third embodiments shown in FIG. 3, respectively, and FIG. 3A shows the position detection of the alignment mark portion of the alignment substrate of the present invention. FIG. 3B is a schematic cross-sectional view showing an example of the method, FIG. 3B is a view of the alignment mark portion seen from the A1 direction of FIG. 3A, and FIG. FIG. 3D is a diagram showing a cross-sectional shape of the surface of the alignment mark portion, and FIG. 4A is a diagram of the alignment mark portion of the alignment substrate of the present invention. FIG. 4B is a diagram showing an example of a schematic configuration for performing position detection, FIG. 4B is a diagram in which the alignment mark portion of the processing substrate and the alignment mark of the mask are overlapped, and FIG. 5 is FIG. FIG. 6 is a flowchart showing an example of a process for producing a color filter forming substrate and a process flow for producing a liquid crystal display panel related to the alignment substrate of the present invention. 7 is a cross-sectional view showing an example of a color filter forming substrate manufactured by the method for manufacturing a color filter forming substrate shown in FIG. 6, and FIG. 8 is a manufacturing method of the color filter forming substrate shown in FIG. It is a sectional view showing a more further example of the produced color filter formation substrate.
In FIG. 1A to FIG. 1C, for the sake of simplicity, the number of the colored layers of the first colored layer to the third colored layer is reduced.
Further, in FIG. 3C, the top portion 22a of the alignment mark portion and the surface portion 22c of the edge bottom have high luminance and are shown as white portions, the dark portion 20B is shown as a shaded portion, and the dark portion 20B is shaded. This is shown for convenience.
FIG. 3D shows a cross section taken along line A2-A3 in FIG.
Further, the imaging apparatus shown in FIG. 3A is shown in a simplified manner, and the lens system is omitted.
Further, S1 to S10 in FIG. 5 and S20 to S29 in FIG. 6 indicate processing steps.
1 to 8, 1 is a transparent substrate, 2a is a first colored layer, 2A is a mark, 3 is a colored resin layer (also referred to as a colored layer), 3A is an alignment mark portion, 3a is a second colored layer, 4 is a colored resin layer (also referred to as a colored layer), 4A is an alignment mark portion, 4a is a third colored layer, 5 is an ITO film, 6 is a colored resin layer (also referred to as a colored layer), and 6a is (for black stripes) ) Colored layer, 6A is an alignment mark portion, 6a is a black stripe, 7 is a color filter forming substrate, 8 is a pixel array, 8a is a pixel region, 10 is a transparent substrate, 10a is a processing substrate (also called a color filter forming substrate) , 20 is an alignment mark portion, 20A is a captured image (of the alignment mark portion), 20B is a dark portion, 20C is a position of the alignment mark portion, 20X is a line in the x direction, 20Y is a line in the y direction, 1 is a mark (of a colored layer), 22 is a colored resin layer (also called a colored layer), 22a is a top portion, 22b is a tapered portion (also called an edge portion), and 22c is a surface portion (also called a bottom surface portion of the tapered portion). , 30 is a mask, 31 is an alignment mark, 35 is a mask holding unit, 40 is an imaging device, 41 is a CCD area sensor, 42 is a half mirror, 43 is a light source (for illumination), 44 is a mirror, 50 is a stage, 55 Is a substrate holding portion, 71 is a first colored layer, 72 is a second colored layer, 73 is a third colored layer, 74 is an ITO film, 75 is a BM layer (also referred to as a light-shielding colored layer), 75A is a semi-light-shielding colored layer, 76 is a black matrix portion (also simply referred to as a black matrix), 80 and 80a are columnar spacers, R ₀ is a red pixel portion, G ₀ is a green pixel portion, and B ₀ is a blue pixel portion. .

An embodiment of an alignment substrate according to the present invention will be described with reference to FIG.
The alignment substrate of the first example shown in FIG. 1 (a), the alignment substrate of the second example shown in FIG. 1 (b), and the alignment substrate of the third example shown in FIG. 1 (c). Are both
This is an intermediate substrate for forming a color filter forming substrate having a pixel array in which pixels of the same color as shown in FIG. 1D are arranged in a stripe pattern, which is not clearly shown in FIG. h), the first colored layer 2a, the second colored layer 3a, and the third colored layer 4a are arranged in a stripe shape, and a black colored layer ( This is a substrate in an intermediate process to form a color filter forming substrate with a cross-sectional structure with black matrix 6a).
The alignment substrate of the first example shown in FIG. 1A is provided with a first colored layer 2a and a mark 2A composed of a colored layer formed from the same colored resin layer as the first colored layer. And it is a thing of the form covered with the colored resin layer 3 for forming the 2nd colored layer in the whole surface so that the 1st colored layer 2a and the mark 2A may be covered.
In the first example, the alignment mark portion 3A is arranged so as to cover the entire mark area and the mark 2A made of a colored layer disposed on one surface of the transparent substrate 1, and to rise along the shape of the mark. It consists of a colored resin layer 3.
The alignment mark part 3A is for detecting the position of the alignment mark part by image processing from an image obtained by photographing the area with the CCD area sensor of the imaging device with specular reflection illumination (epi-illumination illumination).
The alignment substrate of the second example shown in FIG. 1B includes a first colored layer 2a, a mark 2A formed of a colored layer formed of the same colored resin layer as the first colored layer, 2 colored layers 3a and covered with a colored resin layer 4 for forming a third colored layer on the entire surface so as to cover the first colored layer 2a, the mark 2A, and the second colored layer 3a. It is in the form.
In the second example, the alignment mark portion 4A is arranged so as to cover the entire mark area and to rise along the shape of the mark 2A formed of a colored layer disposed on one surface of the transparent substrate 1. It consists of a colored resin layer 4.
The alignment mark portion 4A is also for detecting the position of the alignment mark portion by image processing from an image obtained by photographing the area with the CCD area sensor of the image pickup device with specular reflection illumination (epi-illumination illumination).
The alignment substrate of the third example shown in FIG. 1C includes a first colored layer 2a, a mark 2A composed of a colored layer formed of the same colored resin layer as the first colored layer, 2 colored layer 3a and third colored layer 4a are disposed, ITO film 5 is disposed so as to cover them, and
The first colored layer 2a, the mark 2A, the second colored layer 3a, and the third colored layer 4a are covered with a colored resin layer 6 for forming a black matrix 6a on the entire surface of the ITO film 5 so as to cover the regions. It is in the form.
In the third example, the alignment mark portion 6A includes a mark 2A made of a colored layer disposed on one surface of the transparent substrate 1, an ITO film 5 covering the entire mark region, and a mark covered with the ITO film 5. It comprises a colored resin layer 6 that covers the entire area and is arranged so as to rise along the shape of the mark.
The alignment mark section 6 is also for detecting the position of the alignment mark section by image processing from an image of the area taken by the CCD area sensor of the image pickup device with specular illumination (epi-illumination).
In addition, for each of the alignment mark portions 3A, 4A, and 6A, when the average inclination of the tapered portion (also referred to as an edge portion) of the cross section across the width of the mark 2A made of the colored layer of each alignment mark portion is θ, The value of tan θ is preferably 0.028 or more.
As described above, in order to sufficiently recognize the taper portion (edge portion), when the gradation of luminance photographed by the CCD area sensor of the imaging apparatus is set to 256 gradations from 0 to 255, when photographing is performed. Although it is required on a practical level that the luminance difference between the brightness of the taper portion (edge portion) that becomes darker and the top portion of the alignment mark portion or the surface portion of the edge bottom that becomes brighter is 0, the value of tan θ is 0. If it is 0.028 or more, it means that the luminance difference can be 10 or more.

The transparent substrate 10 is preferably a low expansion and good transparency, and although a glass substrate is used here, it is not limited to this.
A plastic substrate or the like is also used.
Here, as the resin colored layers for forming the colored layers of the first colored layer 2a, the second colored layer 3a, and the third colored layer 4a, respectively, an ultraviolet curable photosensitive resin, a pigment, A pigment-dispersed coloring material in which a dye or the like is mixed and dispersed is used.
As the colored layers of the first colored layer 2a, the second colored layer 3a, and the third colored layer 4a, usually colored layers of R (red), G (green), and B (blue) are used. It is done.

Next, the manufacturing process of the alignment substrate according to the first to third examples and the manufacturing process of the color filter forming substrate manufactured using these as an intermediate substrate will be briefly described with reference to FIG. deep.
A transparent substrate 1 is prepared (FIG. 2 (a)), a photosensitive colored resin layer for forming the first colored layer 2a is applied on one side (not shown), and the colored resin layer is applied. The first colored layer 2a and the mark 2A are formed on one surface of the transparent substrate 1 by a photolithographic method in which the film is selectively exposed through an exposure mask and developed. (Fig. 2 (b))
As the colored resin layer, an ultraviolet curable photosensitive resin in which pigments, dyes, and the like are mixed and dispersed is used.
The exposure here is proximity exposure.
Thereafter, the first colored layer 2a and the mark 2A are coated and covered with the colored resin layer 3 for forming the second colored layer over the entire surface, thereby producing the alignment substrate of the first example. . (FIG. 2 (c)) Next, the second colored layer 3a is formed on one surface of the transparent substrate 1 by a photolithography method in which the colored resin layer 3 is selectively exposed through an exposure mask and developed. Further form. (Fig. 2 (d))
Here, as the colored resin layer 3, a mixture obtained by mixing and dispersing a pigment, a dye or the like in an ultraviolet curable photosensitive resin is used, and proximity exposure is adopted.
Next, a colored resin layer 4 for forming a third colored layer is applied and covered on the entire surface so as to cover the first colored layer 2a, the mark 2A, and the second colored layer 3a. A substrate for alignment is prepared. (Fig. 2 (e))
Thereafter, the colored resin layer 4 is selectively exposed through an exposure mask, and a third colored layer 4a is further formed on one surface of the transparent substrate 1 by a photolithographic method in which development processing is performed. (Fig. 2 (f))
Here, as the colored resin layer 4, an ultraviolet curable photosensitive resin mixed with a pigment, a dye or the like and dispersed is used, and proximity exposure is adopted.
Next, after forming the ITO film 5 over the entire surface so as to cover the colored layers 2a, 3a, 4a and the mark 2A by sputtering, the first colored layer 2a, the mark 2A, the second colored layer 3a, the third A colored resin layer 6 for forming a black matrix 6a is applied and covered on the entire surface of the ITO film 5 so as to cover the region of the colored layer 4a, thereby producing a substrate for alignment of the third example. (Fig. 2 (g))
An ITO film is formed as a single layer film on each colored layer of the treatment substrate by sputtering under a predetermined sputtering condition using an ITO sintered body as a target.
Thereafter, the colored resin layer 6 is selectively exposed through an exposure mask, and a black matrix 6a is further formed at the boundary of each colored layer by a photolithography method in which development processing is performed. (Fig. 2 (h))
Here, as the colored resin layer 6, a material obtained by mixing and dispersing a pigment, a dye or the like in an ultraviolet curable photosensitive resin is used, and proximity exposure is employed.
In this way, the color filter forming substrate 7 shown in FIG.

Next, an example of the position detection method of the alignment mark portion of the alignment substrate according to the present invention will be described with reference to FIG.
The position detection method of the alignment mark part of this example is a position detection method of the alignment mark part, which is adopted when patterning the colored layer in the production of the color filter forming substrate. On one surface of the transparent substrate 10, R, G, B And a colored resin layer (also referred to as a colored layer) that is applied so as to cover the mark 21 and that has one color of R, G, and B different from the color of the mark portion. Alignment portion for detecting the position of the mark 21 in the alignment mark portion 20 is defined as a portion including the region where the colored resin layer 22 is raised along the mark 21. This is a mark position detection method of the mark unit 20.
Then, the position of the alignment mark part is detected by image processing from an image obtained by photographing the area including the alignment mark part 20 by the CCD area sensor 41 through the lens system (not shown) by the imaging device 40. To do.
In particular, in this example, the imaging device 40 is used for imaging a region including the alignment mark part 20 with specular reflection illumination (epi-illumination), whereby the alignment mark part 20 having such a structure can be obtained. The shape of the raised area along the mark 21, particularly the position of the mark 21 in the alignment mark portion 20 can be recognized.
Here, the position of the alignment mark part 20 is detected, and this is used as the position of the mark 21. As described above, if the surface of the alignment mark part is photographed and its shape can be sufficiently recognized, By recognizing that the center position of the mark made of the colored layer (also simply referred to as the mark position) corresponds to the center position of the captured alignment mark portion, by photographing with specular reflection illumination (epi-illumination illumination), This is because the shape can be sufficiently recognized by photographing the surface of the alignment mark part. Thus, by detecting the position of the mark 21 of the alignment mark part 20 in this way, the position of the mark 21 can be substantially detected. It can be done by level.

First, as shown in FIG. 3A, the imaging device 40 is set at the position of the alignment mark portion of the processing substrate 10a, and the light source of illumination light is set.
Then, the alignment mark part 20 is image | photographed with the falling illumination of illumination light with an imaging device. As shown in FIG. 3A, the illumination light from the light source is reflected through the half mirror 42 of the imaging device, and falls on the alignment mark unit 20.
At the time of shooting, the reflected light from the alignment mark part 20 due to falling illumination passes through the half mirror 42 of the imaging device and enters the CCD area sensor 41.
Here, the mark 21 has a cross shape, and as shown in FIG. 3A, the alignment mark portion 20 swells in a cross shape along the mark shape and has a top portion 22a and a tapered portion (edge portion) 22b. Therefore, the intensity of the reflected light is large at the top portion 22a, small at the taper portion (edge portion), and large at the surface portion 22c of the taper bottom (edge bottom). As shown in FIG. 3C, the image obtained by photographing the alignment mark portion 20 (see FIG. 3B) with the reflected light is bright at the top portion 22a and the edge bottom surface portion 22c and dark at the edge portion.
The outer shape of the cross section at A2-A3 in FIG. 3B is as shown in FIG. 3D, but when the average inclination of the edge portion 22b is θ, the value of tan θ is 0.028 or more. Can be recognized well at a practical level.
In addition, the average inclination is roughly shown in FIG. 3 (d) in the region excluding the rising part where the slope of the taper part (edge part) 22b is gentle and the part where the slope near the apex is gentle. Average slope.

After photographing the alignment mark part 20, the image processing part processes this using the image photographed by the alignment mark part 20 (see FIG. 3C), for example, the center y position of the line 20X in the x direction. Then, the position (x, y) of the alignment mark portion 20 is obtained from the center y position of the y-direction line 20Y and detected as the position of the mark 21.
In this way, the position of the mark 21 of the alignment mark portion 20 is obtained.
For image processing, for example, image data of a photographic image displayed in gradation (see FIG. 3C) is binarized at a predetermined slice level for each pixel, and a dark tapered portion (edge portion) is obtained. Obtained from the binarized image data in which the bright portion such as the top portion 22a of the alignment mark portion 20 and the surface portion 22c of the tapered bottom (bottom of the edge) is white is obtained. The center position y of the line in the x direction and the center position of the line in the y direction are obtained.
Here, this is the position of the alignment mark portion 20, and the position of the mark 21 is substantially conceived.
With respect to the captured image, smoothed image data obtained by performing a smoothing process on the vicinity region of each pixel is obtained, and this image data is binarized at a predetermined slice level for each pixel, and a dark tapered portion (edge portion) is obtained. After obtaining binarized image data in which the bright portions such as black, the top portion 22a of the alignment mark portion 20 and the surface portion 22c of the taper bottom (bottom of the edge) are white, further, from the obtained binarized image data The center y position of the line in the x direction and the center position of the y direction line may be obtained.
Note that the smoothing process here is, for example, a new pixel value for each pixel of the original image (captured image) data, with the center value of the histogram of all the pixels in the vicinity region of the pixel as a new pixel value. Image data is obtained and used as smoothed image data.

As the light source 43 for illumination, for example, when the mark is made of a red (R) colored layer and the resin colored layer covering the mark is blue (B), an infrared LED is used.
The imaging device including the CCD area sensor 41 is not particularly limited.

Next, an example of an alignment method using the position detection method of the alignment mark portion of the alignment substrate according to the present invention will be further described with reference to FIGS.
Here, the alignment mark portion position detection method described in FIG. 3 has a color filter portion composed of a colored layer of each color and a BM composed of a colored layer on one surface of a transparent substrate. TN type (twisted nematic mode) liquid crystal display panel, which is formed with a colored layer for forming each color filter portion and BM portion, and an ITO layer is disposed on the color filter portion of each color When producing a color filter forming substrate for use, it is applied to alignment in a photolithography process of a colored layer.
The alignment is performed with an apparatus configuration as shown in FIG.
The processing substrate 10a shown in FIG. 4 has alignment mark portions 20 (see FIG. 3) having marks 21 made of a colored layer at two locations on the processing substrate 10a, and two corresponding locations on the mask 30 for exposure. Alignment is performed with the alignment mark 31.
Here, the processing substrate 10a is subjected to proximity exposure whose position is fixed by the mask holding unit 35 while being held by the substrate holding unit 55 fixed on the stage 55 whose position coordinates are managed. The exposure mask 30 and a predetermined gap interval are provided.
Then, each alignment mark portion 20 of the processing substrate 10a is roughly aligned with the corresponding alignment mark 31 of the exposure mask 30 so that the two alignment marks 31 of the exposure mask 30 can be photographed. The imaging device 40 and the light source unit 43 having the configuration shown in FIG. (S1-S2)
Thereafter, each imaging device 40 photographs each alignment mark of the mask 30 at each position, and captures it as a photographed image at the coordinate position (coordinate position for managing the stage). (S3)
On the other hand, at each of the coordinate positions, each imaging device 40 photographs the alignment mark portion 20 of the processing substrate 10a as described above with reference to FIG. 3, and the coordinate position (coordinate position for managing the stage). Capture as a captured image. (S4)
Here, alignment marks 31 and 21 having shapes as shown in FIG. 4B are used.
Next, the image data Dm1 and Dm2 of each alignment mark 31 of the mask 30 obtained by photographing and the image data Da1 of each alignment mark part 20 of the processing substrate 10a obtained by photographing by the position detection method of the alignment mark part described above with reference to FIG. , Da2 are used to detect the positions of the alignment marks 31 and the alignment mark portions 20, respectively. (S4 to S5, S7 to S8)
In FIG. 4B, the center position of each alignment mark in the x and y directions is the position.
The positional deviation between the alignment mark 31 and the alignment mark part 20 at each corresponding position is calculated and extracted. (S9)
Next, based on the extracted displacement amount of each position, a stage movement amount that corrects this is calculated, and the stage movement is performed based on the calculated result. (S10)
In this way, alignment between the mask 30 and the processing substrate 10a is performed.

Next, an example of a method for producing a color filter forming substrate, which employs an alignment method using the alignment mark position detection method of the present invention, will be described.
In this example, a color filter portion of each color composed of a colored layer of each color and a BM composed of a colored layer are provided on one surface of a transparent substrate, and a column portion (also referred to as a spacer) is formed on each color filter portion and BM portion. A color filter forming substrate for producing a color filter forming substrate for a liquid crystal display panel of a TN mode (Twisted Nematic mode), which is formed of a colored layer for forming a color filter and an ITO layer is disposed on a color filter portion of each color The photosensitive coloring resin for forming each colored layer is applied on one surface of the transparent substrate, selectively exposed through a photomask, and developed, whereby each color is formed into a desired shape. The photolithography process for forming the layers is performed by the number of the colored layers to be formed, and each color filter portion, black matrix portion (also referred to as BM portion), column portion (also referred to as spacer). ) It is intended to form.
The exposure in each of the photolithographic steps is performed by a proximity exposure method through a photomask, with the other surface of the transparent substrate being placed on the stage (mounting table) side. Alignment at the time of each photolithography process after the first time is the alignment method described in FIG. 4, and includes an alignment mark portion provided on the transparent substrate side and a light shielding layer such as Cr of a photomask for exposure. Each of the alignment mark portions including an alignment mark portion region by an image sensor provided on the light source side of the photomask and an area sensor of pixel division such as a CCD through a lens system. The position is detected from the captured image by image processing, and relative to the detected position This is performed by moving the position of the photomask and the transparent substrate, and is formed by a colored layer formed by the first photolithographic process, and is applied in each of the second and subsequent photolithographic processes covering the mark. A colored resin layer made of a photosensitive colored resin for forming a colored layer is used as the alignment mark portion, and the alignment mark portion is photographed by the imaging device with specular illumination (epi-illumination). It is.

The color filter forming substrate and a method for manufacturing a liquid crystal display panel using the color filter forming substrate are performed, for example, by a processing flow shown in FIG.
In brief, first, a red R layer is formed as a first layer on one surface of a transparent substrate by photolithography. (S20-S21)
As the transparent substrate 10, a substrate having low expansion and good transparency is preferable, and although a glass substrate is used here, it is not limited to this.
A plastic substrate or the like is also used.
At this time, a mark (corresponding to 21 in FIG. 3) is formed.
Next, a photosensitive resin colored layer for forming a blue B layer is applied so as to cover the processing substrate including the mark, and after drying, the alignment mark portion described with reference to FIGS. 4 and 5 is used. Alignment is performed by an alignment method using a position detection method, exposure is performed, and development is performed to form a second B layer. (S22)
Next, similarly, a photosensitive resin colored layer for forming a green G layer is applied so as to cover the processing substrate including the mark, and after drying, the alignment described with reference to FIGS. 4 and 5 above. Alignment is performed by an alignment method using the mark position detection method, exposure is performed, and development is performed to form a third G layer. (S23)
In the R layer forming process (S21), a red colored layer in which a pigment, a dye, or the like is mixed and dispersed in an ultraviolet curable photosensitive resin is applied to one surface of the transparent substrate 10 and formed into a predetermined shape by photolithography. A first colored layer (also referred to as a red colored layer or R layer) is formed in a predetermined region.
Similarly, in the B layer forming process (S22), the first colored layer of the transparent substrate 10 was formed by dispersing a blue colored layer in which a pigment, a dye or the like was mixed and dispersed in an ultraviolet curable photosensitive resin. A second colored layer (also referred to as a blue colored layer or B layer) is formed in a predetermined region by applying to the side surface and forming a predetermined shape by photolithography.
Similarly, in the G layer forming process (S23), a green colored layer obtained by mixing and dispersing a pigment, a dye, or the like in an ultraviolet curable photosensitive resin is used as the first colored layer, two layers of the transparent substrate 10. A third colored layer (also referred to as a green colored layer or G layer) is formed by applying to a surface on which the colored layer of the eye is formed and applying a predetermined shape by a photolithography method.

Next, an ITO film is formed as a single layer film on each colored layer of the processing substrate by sputtering under a predetermined sputtering condition using an ITO sintered body as a target. (S24)
Sputtering for forming an ITO film for a control electrode is generally performed in a film composition (for example, In ₂ O) under an Ar gas atmosphere under a pressure of 1 × 10 ⁻⁵ torr to 1 × 10 ⁻² torr. ₃ , 90 w% + SnO ₂ , 10 w% composition), and an ITO sintered body having a thickness of 8 mm to 15 mm is used as a target material, and the direct current magnetron sputtering method is used.
As the target, a target plate is usually used in which a Cu plate is used as a backing material, indium solder is used as an adhesive layer, and a large number of sintered target materials are joined together.
In the production of a color filter forming substrate in which an ITO film is disposed as a control electrode, the ITO film is formed by sputtering on the colored layer forming the color filter. In view of the property and degassing from the colored layer forming the color filter, it is required to form the film at a low temperature.

Next, similar to the formation of the second and third colored layers, a photosensitive resin colored layer for forming a black BM layer is applied so as to cover the processing substrate including the mark, and after drying, the above-mentioned Alignment, exposure, and development are performed by the alignment method using the alignment mark position detection method of the present invention described with reference to FIGS. 2 and 3 to form a BM layer. (S25)
In this way, a color filter forming substrate (also referred to as a CF substrate) is formed. (S26)

The color filter forming substrate formed in this way has a shape as shown in FIG. 7, for example.
Here, the columnar spacer 80 is formed so that the colored layers of the respective colors are stacked when the colored layers are formed.
The BM layer is the top layer.
In order to form the colored layer of each color by changing the thickness, here, the light-shielding film that shields the exposure light at the time of transfer onto one surface of the transparent substrate and the semi-transmissive to the exposure light are described here. A halftone film having a light-shielding film, a halftone area in which there is no light-shielding film and a halftone film is provided, and a light-shielding film and a halftone film. A gradation mask provided with a transparent region in which none exists is used.

A color filter forming substrate (S26) thus prepared and a TFT substrate (S27) to be bonded to form a liquid crystal panel are prepared in advance.
Then, an ultraviolet curable sealing material is applied to the outer peripheral sealing region of the color filter forming substrate transparent conductive film forming substrate 110 of this example by, for example, a dispenser or printing to obtain a predetermined height. A spacer is formed, and liquid crystal is disposed in the frame-like spacer by a dropping method, and then bonded to the TFT substrate. (S28)
At the time of bonding, the sealing material is cured by irradiating the sealing material in the sealing region with ultraviolet rays from the transparent substrate (corresponding to 10 in FIG. 3) side of the color filter forming substrate.
In this manner, a liquid crystal display panel using the color filter forming substrate of this example is manufactured. (S29)

In addition, the manufacturing method of the said color filter formation board | substrate is an example, and is not limited to these.
For example, instead of the light shielding by the BM layer shown in FIG. 7, as shown in FIG. 8, the black matrix part and the column part are formed by the light shielding by the R, G, B colored layers and the semi-light-shielding (gray) colored layer. You may do it.
The fabrication in this case is basically the same as the fabrication method described with reference to FIG. 6, and the columnar spacer 80a and the black matrix portion 76 are fabricated at the time of forming each color of R, G, and B.
Also in this case, in order to form the colored layers of the respective colors with varying thicknesses, here, the light shielding film that shields the exposure light at the time of transfer onto one surface of the transparent substrate, and the exposure light described above are used. The semi-transparent halftone film is patterned and arranged, and the light-shielding area provided with the light-shielding film, the halftone area provided with the half-tone film without the light-shielding film, the light-shielding film and the half-tone film A gradation mask provided with a transparent region where none of the tone films exists is used.
Further, the arrangement of the colored pixels can be applied to various arrangements such as a known mosaic type and a triangle type in addition to the stripe type in which each colored layer is arranged in a stripe shape.

FIG. 1A is a schematic cross-sectional view of a first example of an embodiment of an alignment substrate of the present invention, and FIG. 1B is an embodiment of the alignment substrate of the present invention. FIG. 1C is a diagram showing a schematic sectional view of the second example of the embodiment of the alignment substrate of the present invention, and FIG. 1D is a diagram showing a schematic sectional view of the second example. ) Is a diagram showing an example of an array of pixels on a color filter forming substrate. 2 (a) to 2 (h) show the first to third embodiments shown in FIGS. 1 (a), 1 (b), and 1 (c), respectively. FIG. FIG. 3A is a schematic cross-sectional view showing an example of the method for detecting the position of the alignment mark portion of the alignment substrate according to the present invention, and FIG. 3B shows the alignment mark portion in the A1 direction of FIG. FIG. 3C is a schematic view showing a photographed image of the alignment mark portion, and FIG. 3D is a view showing a cross-sectional shape of the surface of the alignment mark portion. FIG. 4A is a diagram showing an example of a schematic configuration for detecting the position of the alignment mark portion of the alignment substrate of the present invention, and FIG. 4B is an alignment between the alignment mark portion of the processing substrate and the mask. It is the figure which overlapped and showed the mark. It is a flowchart of an example of a process of the alignment method shown to Fig.4 (a). It is the processing flow figure which showed one example of the manufacturing method of the color filter formation board | substrate in connection with the board | substrate for alignment of this invention, and the processing flow of manufacture of a liquid crystal display panel. It is sectional drawing which showed one example of the color filter formation board | substrate produced with the preparation method of the color filter formation board | substrate shown in FIG. It is sectional drawing which showed another example of the color filter formation board | substrate produced with the preparation method of the color filter formation board | substrate shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Transparent substrate 2a 1st colored layer 2A Mark 3 Colored resin layer (it is also called a colored layer)
3A Alignment mark portion 3a Second colored layer 4 Colored resin layer (also referred to as colored layer)
4A Alignment mark portion 4a Third colored layer 5 ITO film 6 Colored resin layer (also called colored layer)
6a Colored layer 6A (for black stripe) Alignment mark portion 6a Black stripe 7 Color filter forming substrate 8 Pixel array 8a Pixel region 10 Transparent substrate 10a Processing substrate (also referred to as color filter forming substrate)
20 Alignment mark portion 20A Captured image 20B (of alignment mark portion) Dark portion 20C Alignment mark portion position 20X x-direction line 20Y y-direction line 21 (of colored layer) mark 22 colored resin layer (also referred to as colored layer)
22a Top 22b Taper (also called edge)
22c surface portion (also referred to as a bottom surface portion of the tapered portion)
30 Mask 31 Alignment Mark 35 Mask Holding Unit 40 Imaging Device 41 CCD Area Sensor 42 Half Mirror 43 Light Source 44 (for Illumination) Mirror 50 Stage 55 Substrate Holding Unit 71 First Colored Layer 72 Second Colored Layer 73 3 First colored layer 74 ITO film 75 BM layer (also referred to as light-shielding colored layer)
75A Semi-light-shielding colored layer 76 Black matrix portion (also simply referred to as black matrix)
80, 80a Columnar spacer R ₀ Red pixel portion G ₀ Green pixel portion B ₀ Blue pixel portion

Claims (4)

  An alignment substrate having an alignment mark portion for alignment on one surface of the transparent substrate, the alignment mark portion comprising a mark formed of a colored layer disposed on one surface of the transparent substrate, and the entire mark region And a colored resin layer disposed so as to rise along the shape of the mark.   2. The alignment substrate according to claim 1, wherein an average inclination of a taper portion (also referred to as an edge portion) of a cross section across the width of the mark formed of the colored layer of the alignment mark portion is represented by tan θ. The substrate for alignment characterized by the value of 0.028 or more.   3. The alignment substrate according to claim 1, wherein the alignment mark portion is used for patterning of a colored layer in the production of the color filter forming substrate. A substrate for alignment, which is used at the time.   4. The alignment substrate according to claim 3, wherein the color filter forming substrate has, on one surface of a transparent substrate, a color filter portion of each color composed of a colored layer of each color, a black matrix portion composed of a colored layer, A color filter forming substrate for a liquid crystal display panel in which a pillar portion is formed with a colored layer for forming each color filter portion and a black matrix portion, and an ITO layer is disposed on each color filter portion. A substrate for alignment, characterized in that there is.

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