JP2010271462A - Photomask for color filter, method for manufacturing color filter, and color filter for transflective liquid crystal display device - Google Patents

Abstract

Manufacturing of a photomask for a color filter and a color filter for forming an optical path difference adjusting layer in which a second photospacer is provided at an appropriate height without causing poor adhesion of the second photospacer having a low height Methods and color filters are provided.
A fine pattern 53 is provided in a mask pattern region corresponding to the formation of a hole He on the upper surface of an optical path difference adjusting layer 57 constituting a color filter. The fine pattern has a light-shielding portion, and has a light-transmitting pattern at the center. A photomask in which a fine pattern has a light-transmitting portion and a light-shielding pattern in the center. When forming the optical path difference adjusting layer, the photomask PM6 is used to form a hole at the position of the upper surface of the optical path difference adjusting layer corresponding to the formation of the second photo spacer PS-12, and the second photo spacer is placed on the hole. Forming.
[Selection] Figure 12

Description

  The present invention relates to the formation of a photo spacer of a color filter for a liquid crystal display device, and in particular, when two types of photo spacers having different heights are formed at the same time, the adhesion of the second photo spacer is not reduced. The present invention relates to a photomask for a color filter that can be formed at an appropriate height, a method for manufacturing the color filter, and a color filter for a transflective liquid crystal display device.

  In a display device such as a liquid crystal display device, it is a useful means to use a color filter for purposes such as color display, reflectance reduction, contrast adjustment, and spectral characteristic control. In many cases, the color filter used in this display device is formed and used as a pixel. As a method for forming a pixel of a color filter used in a display device, a printing method, a photolithography method, and the like can be given as methods that have been practically used.

  FIG. 1 is an enlarged plan view illustrating an example of a pixel of a color filter used in a liquid crystal display device. 2 is a cross-sectional view taken along line XX of the pixel of the color filter shown in FIG. As shown in FIGS. 1 and 2, the color filter used in the liquid crystal display device has a black matrix (41), a colored pixel (42), and a transparent conductive film (43) sequentially on a glass substrate (40). It is formed.

  As a method of manufacturing the color filter used in the liquid crystal display device, first, a black matrix (41) is formed on a glass substrate (40), and then black on the glass substrate on which the black matrix (41) is formed. A method of forming a colored pixel (42) in alignment with a matrix pattern (opening) and further forming a transparent conductive film (43) is widely used.

  The black matrix (41) has a light-shielding property, determines the position of the colored pixels on the glass substrate at the opening, makes the size of the colored pixels uniform, and when used in a display device It has a function of blocking unwanted light and making the image of the display device a uniform image with no unevenness and an improved contrast. The black matrix (41) is formed by, for example, providing a black photoresist coating film on a glass substrate (40), and pattern exposure and development through the photomask on the coating film to remove unnecessary portions of the resist. A photolithography method is employed in which a black matrix is formed by removing the remaining resist.

The colored pixels (42) have, for example, red, green, and blue filter functions, and are negative types in which pigments and other pigments are dispersed on a glass substrate (40) on which a black matrix is formed. A photolithographic method is employed in which a colored photoresist coating film is provided, and colored pixels are formed by exposure and development of the coating film through a photomask.
In addition, the transparent conductive film (43) is formed by forming a transparent conductive film on a glass substrate on which colored pixels are formed by sputtering using ITO (Indium Tin Oxide), for example.

The color filter manufactured by the above method has a basic function as a color filter used in a liquid crystal display device. With the practical use of various liquid crystal display devices, color filters used in liquid crystal display devices have, for example, 1) a protective layer (overcoat layer) and 2) a protrusion having a spacer function, in addition to the above basic functions. 3) An alignment control protrusion for controlling the alignment of the liquid crystal, 4) an optical path difference adjusting layer for aligning phases of light passing through the transmissive display area and the reflective display area, and 5) light scattering to the reflective display area. Various functions such as layers have been added based on the use and specifications of the color filter.

  For the formation of the protrusions, a photolithography method is used in which a photoresist is applied and pattern exposure is performed on the photoresist through a photomask having a predetermined pattern, development, and, if necessary, the cured resist is cured. Technology has been proposed. Hereinafter, the protrusion formed using the photolithography method is referred to as a photo spacer.

FIG. 3 is a cross-sectional view schematically showing an example of a color filter used in a liquid crystal display device provided with two types of photo spacers having different heights. As shown in FIG. 3, in this color filter, a black matrix (41), a colored pixel (42), a transparent conductive film (43), and a photo spacer are sequentially formed on a glass substrate (40).
The photo spacer is composed of a first photo spacer (PS-1) and a second photo spacer (PS-2) having different heights.

The first photospacer (PS-1) sets a gap between the substrates in order to provide a space for putting liquid crystal between the substrates facing a color filter and a substrate (not shown) facing each other. The first photospacer (PS-1) is deformed when a load is applied to the panel, and is restored when the load is removed. Moreover, it has the elasticity which deform | transforms following the thermal expansion and thermal contraction of the liquid crystal with temperature.
The second photospacer (PS-2) is a photospacer having a lower height than the first photospacer (PS-1). The second photospacer (PS-2) is for preventing the plastic deformation and destruction of the first photospacer (PS-1) by dispersing the load when an excessive load is applied to the panel.

  The difference (ΔH) between the height (H1) of the first photo spacer (PS-1) and the height (H2) of the second photo spacer (PS-2) is preferably about 0.3 μm. The range of height difference (ΔH) is about 0.3 to 0.6 μm.

  When manufacturing a color filter having a specification in which the photo spacer shown in FIG. 3 is added to the color filter shown in FIGS. 1 and 2, for example, a second photo spacer (PS- 2) must be formed, it is considered to use a photoresist of a material different from the photoresist used for forming the first photospacer (PS-1) for forming the second photospacer (PS-2). It is done.

  In this case, two steps of forming a first photospacer (PS-1) and a step of forming a second photospacer (PS-2) using two different kinds of materials are added and desired. The specified color filter will be manufactured. However, if two types of materials are used and the process is performed twice, the material cost increases, and the number of processes increases, so that the manufacturing cost of the color filter increases. Therefore, in many cases, the same photo resist is used and the first photo spacer (PS-1) and the second photo spacer (PS-2) having a lower height than the first photo spacer (PS-1) are simultaneously used. The color filter is manufactured inexpensively by the forming method.

As a first method for simultaneously forming two types of photo spacers having different heights using the same photoresist, for example, a light transmission pattern (hereinafter referred to as an opening) formed on a photomask to be used. And reducing the intensity of light applied to the photoresist to form a photo spacer with a low height.
FIG. 4 is a cross-sectional view illustrating the first method. As shown in FIG. 4, a photoresist layer (60) is formed on a glass substrate (40) on which a black matrix (41), a colored pixel (42), and a transparent conductive film (43) are sequentially formed. A photomask (PM1) is disposed above the gap (interval) (G) for proximity exposure.

A pattern (opening) corresponding to the formation of the first photospacer (PS-1c) and the second photospacer (PS-2c) is formed on the photomask (PM1). The film surface (51) of the photomask faces the photoresist layer (60). FIG. 4 shows an example in which a negative photoresist is used.
The width (W3) of the pattern (opening) corresponding to the formation of the first photospacer (PS-1c) on the photomask (PM1) is substantially equal to the width of the first photospacer (PS-1c) to be formed. Are the same.

  On the other hand, the width (W4) of the pattern (opening) corresponding to the formation of the second photo spacer (PS-2c) having a height lower than that of the first photo spacer (PS-1c) is the first photo spacer (PS-1c). ) Is narrower than the width (W3) of the pattern (opening) corresponding to the formation of () (W3> W4). This is to reduce the light intensity by narrowing the width of the pattern (opening) and to form a photo spacer with a low height.

  The exposure light (E) from above the photomask (PM1) is irradiated to the photoresist layer (60) through the opening of the photomask, but the first photospacer (PS-1c) having a width (W3). If there is sufficient proximity exposure gap (G) in the opening corresponding to the formation of, the irradiated light is diffracted not only at the photoresist layer (60) portion below the opening but also at the opening edge. As a result, the light intensity reaches the lower part of the light-shielding part adjacent to the opening, and the light intensity at the edge of the opening is reduced accordingly, and the shape of the first photo spacer (PS-1c) after development indicated by the dotted line in FIG. And a trapezoidal shape having a height (H3).

On the other hand, in the opening corresponding to the formation of the second photospacer (PS-2c) having the width (W4), part of the irradiated light is diffracted at the end of the opening, so that the light shielding portion adjacent to the opening Since the width of the opening reaches a lower part and the width of the opening is narrow, the intensity of light applied to the portion of the photoresist layer (60) below the opening is weakened.
Therefore, as shown by a dotted line in FIG. 4, the height of the second photo spacer (PS-2c) after development is lower than the height (H3) of the first photo spacer (PS-1c) (H4). ).

  The advantage of the first method of simultaneously forming two kinds of photo spacers having different heights using the same photoresist is that the second height of the desired height is adjusted by adjusting the width of the opening on the photomask. Since the photo spacer (PS-2c) can be obtained, the structure of the photo mask to be used is simple and inexpensive.

In addition, the disadvantages of the first method are that a) the width (W4) of the second photospacer (PS-2c) is narrower than the width (W3) of the first photospacer (PS-1c). Since the bottom area of the second photospacer (PS-2c) having a small width is reduced, the adhesion strength to the transparent conductive film is reduced, and it is easy to peel off from the transparent conductive film (43). is there. b) Further, since the exposure to the photoresist layer (60) is performed so that the first photospacer (PS-1c) is satisfactorily formed, the exposure to the second photospacer (PS-2c) is Insufficiently, the photoresist may not be sufficiently cured, which is a difficulty in stably forming the second photospacer (PS-2c) having an appropriate height difference.
In the present application, the first method is referred to as a small aperture mask method.

In addition, as a second method of simultaneously forming two types of photo spacers having different heights using the same photoresist, for example, in the pattern (opening) of the photomask to be used, for example, the resist is resolved. For example, a light-shielding pattern (gray tone) as fine as possible is provided to reduce the light intensity and form a low-height photo spacer.
FIG. 5 is a cross-sectional view illustrating the second method. As shown in FIG. 5, a photoresist layer (60) is formed on a glass substrate (40) on which a black matrix (41), a colored pixel (42), and a transparent conductive film (43) are sequentially formed. A photomask (PM2) is arranged above the gap (gap) (G) for proximity exposure.

In the photomask (PM2), patterns (openings) corresponding to the formation of the first photospacer (PS-1d) and the second photospacer (PS-2d) are formed. The film surface (51) of the photomask faces the photoresist layer (60). FIG. 5 shows an example in which a negative photoresist is used.
The width (W5) of the formed first photo spacer (PS-1d) and the width (W6) of the formed second photo spacer (PS-2d) are substantially the same. The relationship between the height (H5) of the first photo spacer (PS-1d) and the height (H6) of the second photo spacer (PS-2d) is H5> H6.

The width (W5) of the pattern (opening) corresponding to the formation of the first photo spacer (PS-1d) of the photomask (PM2) is substantially the same as the width of the first photo spacer (PS-1d) to be formed. It is.
The width (W6) of the pattern (opening) corresponding to the formation of the second photo spacer (PS-2d) having a lower height than the first photo spacer (PS-1d) is the second photo spacer ( It is substantially the same as the width of PS-2d).

A fine pattern (gray tone) (52) is provided in the opening of the photomask (PM2) corresponding to the formation of the second photospacer (PS-2d). When the photoresist layer (60) is properly exposed so that the first photospacer (PS-1d) having the height (H5) can be satisfactorily formed, the height (H6) The average density of the pattern area, such as the size, pattern shape, density, etc., of the fine pattern (gray tone) (52) is set so that the exposure to the two-photo spacer (PS-2d) is also performed appropriately.
Examples of the fine pattern (gray tone) (52) include a fine pattern formed by photoetching a chromium film formed when a photomask is manufactured.

  The exposure light (E) from above the photomask (PM2) is irradiated to the photoresist layer (60) through the opening of the photomask, but the first photospacer (PS-1d) having a width (W5). If there is sufficient proximity exposure gap (G) in the opening corresponding to the formation of, the irradiated light is diffracted not only at the photoresist layer (60) portion below the opening but also at the opening edge. As a result, the light intensity reaches the lower part of the light-shielding part adjacent to the opening, and the light intensity at the end of the opening is reduced accordingly. As shown by the dotted line in FIG. 5, the first photospacer (PS-1d) after development The shape is a trapezoid having a height (H5).

On the other hand, in the opening corresponding to the formation of the second photospacer (PS-2d) having the width (W6), if there is a sufficient gap (G) for the proximity exposure, the light intensity irradiated at the opening is Since the light is weakened with a substantially uniform intensity, the height (H6) of the second photo spacer (PS-2d) after development is lower than H5 as shown by the dotted line in FIG. It will have.
In addition, the irradiated light is not only at the photoresist layer (60) below the opening but also at the end of the opening, similarly to the opening corresponding to the formation of the first photospacer (PS-1d). Due to the diffraction, it reaches the lower part of the light-shielding part adjacent to the opening, so that it becomes trapezoidal.

  Therefore, as shown by the dotted line in FIG. 5, the height (H6) of the second photospacer (PS-2d) after development is lower than the height (H5) of the first photospacer (PS-1d), The widths have substantially the same width (H6 <H5, W6≈W5).

  The advantage of the second method of simultaneously forming two types of photo spacers having different heights using the same photoresist as described above is that the light intensity is adjusted by the density of the fine pattern (gray tone) (52). Therefore, it is easy to form a second photospacer (PS-2d) that is appropriately photocured. In addition, there is a degree of freedom in setting the opening width (W6) arbitrarily. For example, the width (W6) of the opening can be made substantially the same as the width (W5) of the opening corresponding to the formation of the first photospacer (PS-1d). The photomask used is inexpensive.

However, the disadvantage of this second method is that the difference in the light intensity of the exposure light tends to occur due to the gap in the proximity exposure, and the instability of the adhesion to the substrate due to the variation in the photocuring of the photoresist (easy to peel off). ) And height variations tend to be large.
In the present application, the second method is referred to as a gray tone mask method.

In addition, as a third method for simultaneously forming two types of photo spacers having different heights using the same photoresist, for example, a halftone is provided in a photomask pattern (opening) to be used to increase the light intensity. There may be mentioned a method of reducing or selecting a bright line of exposure light for curing the photoresist and forming a photo spacer having a low height.
FIG. 6 is a cross-sectional view illustrating the third method. As shown in FIG. 6, a photoresist layer (60) is formed on a glass substrate (40) on which a black matrix (41), a colored pixel (42), and a transparent conductive film (43) are sequentially formed. A photomask (PM3) is arranged above the gap (G) for proximity exposure.

The photomask (PM3) is formed with patterns (openings) corresponding to the formation of the first photospacer (PS-1e) and the second photospacer (PS-2e). The film surface (51) of the photomask faces the photoresist layer (60). FIG. 6 shows an example in which a negative photoresist is used.
The width (W7) of the formed first photo spacer (PS-1e) and the width (W8) of the formed second photo spacer (PS-2e) are substantially the same. The relationship between the height (H7) of the first photo spacer (PS-1e) and the height (H8) of the second photo spacer (PS-2e) is H7> H8.

The width (W7) of the pattern (opening) corresponding to the formation of the first photo spacer (PS-1e) of the photomask (PM3) is substantially the same as the width of the first photo spacer (PS-1e) to be formed. It is.
The width (W8) of the pattern (opening) corresponding to the formation of the second photo spacer (PS-2e) having a lower height than the first photo spacer (PS-1e) is the second photo spacer ( It is substantially the same as the width of PS-2e).

In the opening corresponding to the formation of the second photospacer (PS-2e) of the photomask (PM3), a halftone (layered portion having a predetermined density in order to reduce the intensity of transmitted light) 53). When the photoresist layer (60) is properly exposed so that the first photospacer (PS-1e) having the height (H7) can be formed satisfactorily, the height (H8) The density of the halftone (53) is set so that the exposure to the two-photo spacer (PS-2e) is also performed appropriately.
As the halftone (53), there is a thin film that attenuates ultraviolet rays, for example, a halftone made of a metal oxide film such as ITO, or a halftone formed by photoetching a chromium film formed when a photomask is manufactured. can give.

  The exposure light (E) from above the photomask (PM3) is applied to the photoresist layer (60) through the opening of the photomask, but the first photospacer (PS-1e) having a width (W5). If there is sufficient proximity exposure gap (G) in the opening corresponding to the formation of, the irradiated light is diffracted not only at the photoresist layer (60) portion below the opening but also at the opening edge. As a result, the light intensity reaches the lower part of the light-shielding part adjacent to the opening, and the light intensity at the edge of the opening is reduced by that amount. As shown by the dotted line in FIG. 6, the first photospacer (PS-1e) after development The shape is a trapezoid having a height (H7).

On the other hand, in the opening corresponding to the formation of the second photospacer (PS-2e) having the width (W8), the irradiated light is light whose intensity is weakened by the halftone (53). As indicated by the dotted line, the height (H8) of the second photospacer (PS-2e) after development has a height lower than H7.
In addition, the irradiated light is not only at the photoresist layer (60) portion below the opening, but also at the opening end, similarly to the opening corresponding to the formation of the first photospacer (PS-1e). Due to the diffraction, it reaches the lower part of the light-shielding part adjacent to the opening, so that it becomes trapezoidal.

Therefore, as shown by the dotted line in FIG. 6, the height (H8) of the second photospacer (PS-2e) after development is lower than the height (H7) of the first photospacer (PS-1e), The widths have substantially the same width (H8 <H7, W8≈W7).
The advantage of the third method of simultaneously forming two types of photo spacers having different heights using the same photoresist is that the light intensity is adjusted by the density of the halftone (53). A cured second photospacer (PS-2e) is formed. Further, the width (W6) of the opening can be arbitrarily set, and the degree of freedom in design is high. For example, the width (W8) of the opening can be made substantially the same as the width (W7) of the opening corresponding to the formation of the first photospacer (PS-1e). Therefore, it is difficult to peel from the transparent conductive film (43), and the second photo spacer (Ps-2e) having an appropriate height difference can be stably formed.

The disadvantage of the third method is that the structure of the photomask is complicated and expensive because a halftone is provided in the opening on the photomask.
In the present application, the third method is referred to as a half-tone mask method.

  FIG. 3 is a cross-sectional view of an example of a color filter provided with two types of photo spacers having different heights. This color filter is an example of a color filter used in a transmissive liquid crystal display device. . In the liquid crystal display device using this color filter, as indicated by white thick arrows in FIG. 3, white light from a lower backlight (not shown) becomes colored light in the colored pixels (42), and the colored pixels ( 42) reaches the upper side (viewer side) in the entire area (W0) in the X-axis direction.

In FIG. 3, the height (H1) of the first photospacer (PS-1) is about 3.3 to 4.5 μm in the transmissive liquid crystal display device. When the difference (ΔH) between the height of the first photospacer (PS-1) and the height of the second photospacer (PS-2) is set to 0.3 μm, the height of the second photospacer (PS-2) (H2) is about 3.0 to 4.2 μm.
When the height (H2) of the second photo spacer (PS-2) is about this level, as shown in Table 1, although there are difficulties in each method, for example, improvement of the photomask material, photo Various ideas such as conditions for forming the spacer have been applied, and it has been adopted as a method for simultaneously forming two types of photo spacers while making up for the difficulties in each method.

  FIG. 7 is a cross-sectional view schematically showing another example of a color filter for a liquid crystal display device provided with two types of photo spacers having different heights. This color filter is a transflective liquid crystal display device having a transmissive display region that displays an image using backlight light and a reflective display region that reflects external light incident on the device and displays an image using reflected light. It is a color filter for. As shown in FIG. 7, a black matrix (41), a colored pixel (42), an optical path difference adjusting layer (47), a transparent conductive film (43), and a photo spacer were sequentially formed on a glass substrate (40). Is.

  The photo spacer in this color filter is composed of a first photo spacer (PS-1b) and a second photo spacer (PS-2b), and the first photo spacer (PS-1b) is similar to the photo spacer shown in FIG. ) Sets the gap between the substrates, and the second photospacer (PS-2b) prevents plastic deformation and destruction of the first photospacer (PS-1) when an excessive load is applied.

  In FIG. 7, one pixel region (Px) is composed of a transmissive display region (Tr) and a reflective display region (Re). The colored pixel (42) includes a colored pixel (42Tr) for transmissive display and a colored pixel (42Re) for reflective display. The colored pixel (42Re) for reflective display is composed of a colored portion (45) and a through hole portion (46).

In a transflective liquid crystal display device, light passes through the liquid crystal twice in the reflective display area. Therefore, in order to align the phase of light passing through the transmissive display area (Tr) and the phase of light passing through the reflective display area (Re), a substrate (not shown) facing the color filter substrate and each display area The interval at is set to transmissive display area: reflective display area = approximately 2: 1.
Since the color filters formed in each display area are formed simultaneously, each display area has the same thickness. Therefore, an optical path difference adjusting layer (47) having a thickness of a transparent photoresist is formed in the reflective display area (Re) by a photolithography method in order to make the distance between the opposing substrate different in the transmissive display area and the reflective display area. A photospacer is formed on the optical path difference adjusting layer (47).

  That is, in FIG. 7, the height (H10) from the upper surface of the transparent conductive film (43) on the colored pixel (42Tr) for transmissive display to the top of the first photospacer (PS-1b), and the optical path difference adjusting layer (47). ) The ratio of the height (H11) from the upper surface of the transparent conductive film (43) to the top of the first photospacer (PS-1b) is approximately 2: 1 (H10: H11 = approximately 2: 1).

  Further, in the color filter for the transflective liquid crystal display device, the height (H11) of the first photo spacer (PS-1b) in FIG. 7 is about 3.3 to 4.2 μm. . When the difference (ΔH) between the height of the first photospacer (PS-1b) and the height of the second photospacer (PS-2b) is set to 0.3 μm, the height of the second photospacer (PS-2b) (H12) is about 1.1 to 1.7 μm.

In the transflective liquid crystal display device, the distance between the opposing substrates in the reflective display area is smaller than the distance between the opposing substrates in the transmissive display area. Therefore, the height (H1) of the first photo spacer (PS-1) shown in FIG. 3, which is a color filter of the transmissive liquid crystal display device, and the first photo spacer (PS) provided in the reflective display region shown in FIG. With respect to the height (H11) of -1b), since the first photospacer (PS-1b) shown in FIG. 7 is provided on the optical path difference adjusting layer (47), there is a relationship of H1> H11. That is, the height (H11) of the first photospacer (PS-1b) shown in FIG. 7 is lower.

  If the height of the first photospacer (PS-1b) is low, the height of the accompanying second photospacer (PS-2b) will be further reduced, and the remaining film ratio will be low, so that it adheres to the substrate. The property becomes poor, and peeling from the base frequently occurs. That is, it becomes difficult to form the second photospacer (PS-2b). This is a problem commonly seen in the first to third methods, but is particularly problematic for color filters used in transflective liquid crystal display devices.

JP 2008-032887 A JP 2008-003534 A Japanese Patent Laid-Open No. 2007-0117133

The present invention has been made in order to solve the problems common to the first to third methods described above. When two types of photo spacers having different heights are formed at the same time using the same photoresist, Even if the first photo spacer is a low photo spacer provided on the optical path difference adjusting layer, the adhesion of the second photo spacer formed at the same time as the first photo spacer is lower. It is an object to provide a photomask for a color filter used in a transflective liquid crystal display device for forming an optical path difference adjusting layer that can be eliminated and that the second photospacer can be provided at an appropriate height. It is what.
It is another object of the present invention to provide a color filter manufacturing method using the color filter photomask and a color filter for a transflective liquid crystal display device.

  The present invention relates to a photomask used for forming an optical path difference adjusting layer constituting a color filter for a transflective liquid crystal display device by a photolithography method using proximity exposure, and a predetermined portion on the upper surface of the optical path difference adjusting layer. In order to form a hole, the photomask for a color filter is characterized in that a fine pattern is provided in a mask pattern region where a hole is to be formed.

  In the color filter photomask according to the present invention, the fine pattern in the mask pattern region has a light-shielding portion whose outer shape is a circle or a polygon, and a light-transmitting pattern at the center thereof. A photomask for a color filter.

  In the color filter photomask according to the present invention, the fine pattern in the mask pattern region has a light-transmitting portion having a circular or polygonal outer shape, and a light-shielding pattern at the center thereof. A photomask for a color filter.

Further, the present invention provides a method for producing a color filter in which two types of photo spacers having different heights are simultaneously formed on an optical path difference adjusting layer.
1) When forming the optical path difference adjusting layer, the photomask according to claim 1, 2, or 3 is used as a photomask, and a photo with a low height out of two types of photospacers having different heights is used. A hole is formed at the position of the upper surface of the optical path difference adjusting layer where the spacer (second photo spacer) is to be formed,
2) A method for producing a color filter, wherein, when two types of photo spacers having different heights are formed simultaneously, a photo spacer having a low height (second photo spacer) is formed on the hole.

  The present invention is also the color filter manufacturing method according to the above invention, wherein the hole has a diameter or width of 3 to 8 μm.

  Moreover, this invention is the color filter for transflective liquid crystal display devices manufactured using the manufacturing method of the color filter as described in Claim 4 or 5.

  In the present invention, in a photomask used when the optical path difference adjusting layer constituting the color filter for a transflective liquid crystal display device is formed by a photolithography method using proximity exposure, a predetermined upper surface of the optical path difference adjusting layer after the formation is formed. In order to form a hole in a site (a site where a low photo spacer (second photo spacer) is formed), a fine pattern is provided in a region on the photomask corresponding to the hole. The fine pattern has a light-shielding portion having a circular or polygonal outer shape, and has a light-transmitting pattern arranged at the center thereof, or a light-transmitting portion having a circular or polygonal outer shape, and has a center at the center. It is assumed that a shading pattern is arranged.

  When an optical path difference adjusting layer is formed by a photolithography method using a photomask having such a fine pattern, a hole is formed on the surface of the optical path difference adjusting layer forming a low photo spacer (second photo spacer). A second photospacer is formed on the top. Any one of the first to third methods described above may be used to form the photospacer, but a photolithography method is used. That is, it is a method in which a photoresist is applied on a base, pattern exposure to the photoresist with a photomask, development, and curing treatment on the remaining photoresist if necessary.

  Here, when a photoresist is applied on the surface including the optical path difference adjusting layer to form a resist layer, the photoresist also enters the holes formed in the optical path difference adjusting layer. Therefore, since the base (base part) of the second photospacer formed by photolithography is embedded in the hole, the base is supported by the hole, and the second part is in contact with the side surface of the base. Adhesion between the photospacer and the optical path difference adjusting layer is improved, and peeling from the optical path difference adjusting layer is prevented.

  Moreover, when a photoresist is applied on the substrate including the optical path difference adjusting layer, the film thickness of the photoresist in the part that has entered the hole formed in the optical path difference adjusting layer is the amount of the photoresist entering the hole, The thickness is less than other parts. That is, the film thickness of the photoresist on the hole is smaller than the film thickness of the other part (the part where the first photo spacer is formed) on the optical path difference adjusting layer.

  Therefore, when the first photo spacer and the second photo spacer are simultaneously formed by the first method to the third method described above, the first photo spacer and the second photo spacer having a large height difference are formed. This is effective when it is desired to increase the height difference between the first photo spacer and the second photo spacer.

Since the portion where the photo spacer is formed becomes a region not involved in image display, if the size of the photo spacer in plan view is increased, the region where the image can be displayed is reduced accordingly. Therefore, the size of the photo spacer in plan view is required to be as small as possible. When the second photospacer formed on the optical path difference adjusting layer is very small, the holes of the optical path difference adjusting layer according to the present invention also need to be correspondingly small.

  When using a positive photoresist to form a small hole, if the light transmission part of the photomask part corresponding to the hole formation area is made too small, or if using a negative photoresist In addition, if the light-shielding portion of the photomask portion corresponding to the hole formation region is made too small, holes cannot be formed in the photoresist even when exposed due to wraparound of light from the surroundings or insufficient light quantity.

  On the other hand, if the size of the hole is too large, there is a problem that the aperture ratio is reduced accordingly. Therefore, in the present invention, by using a photomask in which the fine pattern described above is formed in a photomask portion corresponding to a portion where a hole is to be formed, formation of a fine hole having an appropriate size in the optical path difference adjusting layer is achieved. It is possible.

In general, the pixel size of the color filter including the transflective color filter is about 20 μm to 30 μm. Therefore, the diameter of the photo spacer that can be arranged on the pixel is generally about 12 μm to 15 μm, and the minimum diameter is about 9 μm.
Here, if the hole diameter is larger than the diameter of the photo spacer (first photo spacer), the formed first photo spacer and the second photo spacer can have a difference in height. Since the hole cannot be covered, a groove (depressed portion) is formed between the edge of the hole and the outer periphery of the photo spacer (second photo spacer), and the flatness of the pixel surface is impaired. .

  On the other hand, in the present invention, the hole diameter is 5 μm to 8 μm, which is smaller than the diameter of the photo spacer (second photo spacer) (for example, the minimum diameter is 9 μm). Therefore, the hole is covered with a photo spacer (second photo spacer), and as described above, the photo spacer having a height difference can be formed, and the hole is hidden because the photo spacer covers the hole, Since there is no recessed portion on the pixel surface, the pixel surface can be flattened.

In addition, since the present invention is a color filter manufactured by using the above-described method for manufacturing a color filter, the second photo spacer can be appropriately disposed without deteriorating the adhesion of the second photo spacer having a lower height. The color filter is provided at the height.
The photomask of the present invention has a conventional pattern except for the hole forming portion.

It is a top view which expands and shows an example of the pixel of the color filter for liquid crystal display devices. It is sectional drawing in the XX line of the pixel of the color filter shown in FIG. It is sectional drawing which showed typically an example of the color filter used for the liquid crystal display device which provided two types of photo spacers from which height differs. It is sectional drawing of the 1st method of forming simultaneously two types of photospacers from which height differs using the same photoresist. It is sectional drawing of the 2nd method of forming simultaneously two types of photo spacers from which height differs using the same photoresist. It is sectional drawing of the 3rd method of forming simultaneously two types of photo spacers from which height differs using the same photoresist. It is sectional drawing which showed typically the other example of the color filter for liquid crystal display devices which provided two types of photo spacers from which height differs. It is sectional drawing which showed an example of the color filter for liquid crystal display devices by this invention. It is sectional drawing to which the part of 2 types of photo spacers shown in FIG. 8 was expanded. It is sectional drawing which shows an example of the exposure method at the time of forming the optical path difference adjustment layer in this invention. It is sectional drawing which shows the other example of the exposure method at the time of forming the optical path difference adjustment layer in this invention. It is sectional drawing explaining an example of the manufacturing method of the color filter which forms simultaneously 2 types of photo spacers from which height differs on an optical path difference adjustment layer.

Hereinafter, the present invention will be described in detail based on the embodiments.
FIG. 8 is a cross-sectional view showing an example of a color filter for a liquid crystal display device according to the present invention in which two types of photo spacers having different heights are provided. This color filter is a color filter for a transflective liquid crystal display device. FIG. 9 is an enlarged cross-sectional view of two photo spacer portions of the color filter shown in FIG.
As shown in FIGS. 8 and 9, a black matrix (41), a colored pixel (42), an optical path difference adjusting layer (57), a transparent conductive film (43), and a photo spacer are sequentially formed on a glass substrate (40). It is formed.

  The optical path difference adjusting layer (57) in the present invention has a second photo spacer (PS-12) firmly adhered to the upper surface thereof and a hole (He) for supporting the lower portion thereof is formed on the upper surface thereof. The photo spacer in this color filter is composed of a first photo spacer (PS-11) and a second photo spacer (PS-12), and the first photo spacer (PS-11) is an opposing substrate (not shown). The second photo spacer (PS-12) prevents plastic deformation and destruction of the first photo spacer (PS-11) when an excessive load is applied.

  In FIG. 8, one pixel region (Px) includes a transmissive display region (Tr) and a reflective display region (Re). The colored pixel (42) includes a colored pixel (42Tr) for transmissive display and a colored pixel (42Re) for reflective display. The colored pixel (42Re) for reflective display is composed of a colored portion (45) and a through portion (through hole portion (46)) formed between the colored portions.

  In addition, an optical path difference adjusting layer (57) is provided to align the phase of light passing through the transmissive display area (Tr) and the phase of light passing through the reflective display area (Re), and the distance between the substrates. Is set to transmissive display area: reflective display area = approximately 2: 1. That is, in FIG. 8, the height (H20) from the top surface of the transparent conductive film (43) on the colored pixel (42Tr) for transmissive display to the top of the first photospacer (PS-11), and the optical path difference adjusting layer (57). ) The ratio of the height (H21) from the top surface of the transparent conductive film (43) to the top of the first photospacer (PS-11) is approximately 2: 1 (H20: H21 = approximately 2: 1).

In FIG. 8, the height (H21) of the first photospacer (PS-11) is approximately 3.3 to 3.
It is about 4.2 μm. When the difference (ΔH) between the height of the first photospacer (PS-11) and the height of the second photospacer (PS-12) is set to 0.3 μm, the height of the second photospacer (PS-12) (H22) is about 1.1 to 1.7 μm. Further, the widths of the first photo spacer (PS-11) and the second photo spacer (PS-12) are substantially the same (W21≈W22).

  The first photo spacer (PS-1) shown in FIG. 3 has a height (H1) and the first photo spacer (PS-11) shown in FIG. 8 has a height (H21) shown in FIG. Since the photospacer (PS-11) is provided on the optical path difference adjusting layer (57), the relationship of H1> H21 is established. That is, the height (H21) of the first photo spacer (PS-11) shown in FIG. 8 is lower.

  The optical path difference adjusting layer (57) in the present invention is provided with a hole (concave depression) (He) on the upper surface thereof. The second photospacer (PS-12) in the present invention is formed on the hole (concave depression) (He) via a transparent conductive film (43). The lower part of the second photospacer (PS-12) is formed to extend to the bottom of the hole (concave depression) (He).

For this reason, the contact area between the second photospacer (PS-12) and the transparent conductive film (43) is increased, and the second photospacer (PS-12) is firmly adhered, and the lower portion of the second photospacer is supported by a concave depression, thereby providing an anchor effect. Is expressed.
Accordingly, the height (H22) of the second photospacer (PS-12) is lower than the height (H1) of the first photospacer (PS-1) shown in FIG. ) Is still lower than the height (H21), but the remaining film ratio is high, the adhesion is not poor, and the second photospacer (PS-12) can be easily formed.

  FIG. 10 is a partial cross-sectional view showing an example of an exposure method when forming the optical path difference adjusting layer (57) in the present invention. As shown in FIG. 10, a photoresist layer (60N) is formed on a glass substrate (40) on which a black matrix and colored pixels are sequentially formed, and a gap (G) for proximity exposure is provided thereabove. A photomask (PM4) is arranged.

In the photomask (PM4), a mask pattern corresponding to the formation of a hole (He) provided on the upper surface of the optical path difference adjustment layer (57) in the mask pattern region (R11) corresponding to the formation of the optical path difference adjustment layer (57). A region (R1) is provided. The film surface (51) of the photomask faces the photoresist layer (60N). FIG. 10 shows an example in which a negative type photoresist is used.
The width (W23) of the hole (He) to be formed and the width (W24) of the mask pattern region (R1) provided in the photomask (PM4) are substantially the same.

  A fine pattern (54) is provided in the mask pattern region (R1) corresponding to the formation of the hole (He) provided on the upper surface of the optical path difference adjusting layer (57) of the photomask (PM4). When the exposure to the photoresist layer (60N) is properly performed so that the optical path difference adjusting layer (57) having the height (H23) is formed satisfactorily, a hole (He having a depth (H24) is formed. The average density of the mask pattern area, such as the shape, size, and density of the fine pattern (54), is set so that exposure to () is performed properly.

  A mask pattern for forming a hole when the photoresist layer is a negative type has, for example, a light shielding portion having a circular or polygonal outer shape as a fine pattern in the mask pattern region. The thing which has a translucent pattern in the center is mentioned.

  FIG. 11 is a partial cross-sectional view showing another example of the exposure method when forming the optical path difference adjusting layer (57) in the present invention. As shown in FIG. 11, a photoresist layer (60P) is formed on a glass substrate (40) on which a black matrix and colored pixels are sequentially formed, and a proximity exposure gap (G) is provided above the photoresist layer (60P). A mask (PM5) is arranged.

In the photomask (PM5), a mask pattern corresponding to the formation of a hole (He) provided on the upper surface of the optical path difference adjustment layer (57) in the mask pattern region (R12) corresponding to the formation of the optical path difference adjustment layer (57). A region (R2) is provided. The film surface (51) of the photomask faces the photoresist layer (60P). FIG. 11 shows an example in which a positive photoresist is used.
The width (W25) of the hole (He) to be formed and the width (W26) of the mask pattern region (R2) provided in the photomask (PM5) are substantially the same.

  A fine pattern (55) is provided in the mask pattern region (R2) corresponding to the formation of the hole (He) provided on the upper surface of the optical path difference adjusting layer (57) of the photomask (PM5). When the exposure to the photoresist layer (60P) is properly performed so that the optical path difference adjusting layer (57) having the height (H25) can be satisfactorily formed, the hole (He) having the depth (H26) is formed. The average density of the mask pattern area, such as the shape, size, and density of the fine pattern (55), is set so that exposure to () is performed properly.

  As a fine pattern at this time, for example, the mask pattern region includes a light-transmitting portion having a circular or polygonal outer shape as a fine pattern, and a light-shielding pattern at the center of the light-transmitting portion. .

FIG. 12 illustrates an example of a color filter manufacturing method in which two types of photo spacers having different heights are simultaneously formed on the optical path difference adjusting layer (57) formed by the exposure method shown in FIG. 10 or FIG. It is sectional drawing. FIG. 12 shows an example of the color filter for the transflective liquid crystal display device shown in FIG.
As shown in FIG. 12, a photoresist layer is formed on a glass substrate (40) on which a black matrix (41), a colored pixel (42), an optical path difference adjusting layer (57), and a transparent conductive film (43) are sequentially formed. (60) is formed, and a photomask (PM6) is disposed above the gap (G) for proximity exposure.

The photomask (PM6) is formed with patterns (openings) corresponding to the formation of the first photospacer (PS-11) and the second photospacer (PS-12). The film surface (51) of the photomask faces the photoresist layer (60). FIG. 12 shows an example in which a negative photoresist is used.
The width (W21) of the formed first photo spacer (PS-11) and the width (W22) of the formed second photo spacer (PS-11) are substantially the same. The relationship between the height (H21) of the first photo spacer (PS-11) and the height (H22) of the second photo spacer (PS-12) is H21> H22.

The width (W21) of the pattern (opening) corresponding to the formation of the first photo spacer (PS-11) of the photomask (PM6) is substantially the same as the width of the first photo spacer (PS-11) to be formed. It is.
The width (W22) of the pattern (opening) corresponding to the formation of the second photo spacer (PS-12) having a lower height than the first photo spacer (PS-11) is the second photo spacer ( It is substantially the same as the width of PS-12).

This is an example in which a halftone (53) is provided in an opening of the photomask (PM6) corresponding to the formation of the second photospacer (PS-12). When the photoresist layer (60) is properly exposed so that the first photospacer (PS-11) having the height (H21) can be formed satisfactorily, the first photospacer (PS-11) having the height (H22) can be obtained. To two photo spacer (PS-12)

  The exposure light (E) from above the photomask (PM6) is irradiated to the photoresist layer (60) through the opening of the photomask, but the first photospacer (PS-11) having a width (W21). If there is sufficient proximity exposure gap (G) in the opening corresponding to the formation of, the irradiated light is diffracted not only at the photoresist layer (60) portion below the opening but also at the opening edge. As a result, the light intensity reaches the lower part of the light-shielding part of the photomask, and the light intensity at the edge of the opening is reduced accordingly. The shape of the first photospacer (PS-11) after development indicated by the dotted line in FIG. A trapezoidal shape having a height (H21).

  On the other hand, in the opening corresponding to the formation of the second photospacer (PS-12) having the width (W22), the irradiated light is a hole (He on the upper surface of the optical path difference adjusting layer depending on the density setting of the halftone (53). ) The portion of the photoresist layer applied in () is cured, and the height (H22) of the second photospacer (PS-12) after development indicated by a dotted line is lower than H7. To do.

40 ... Glass substrate 41 ... Black matrix 42 ... Colored pixel 42Tr ... Transparent display colored pixel 42Re ... Reflective display colored pixel 43 ... Transparent conductive film 47, 57 ... Optical path Difference adjustment layer 46 ... through hole 52 ... fine pattern (gray tone)
53... Halftones 54 and 55. Fine patterns 60, 60 N and 60 P of the present invention. Photoresist layer E... Exposure light G... Gap H 1, H 3, H 5, H 7 and H 11 ... height H2, H4, H6, H8, H12 of the first photo spacer ... height H21 of the second photo spacer ... height H22 of the first photo spacer in the present invention ... in the present invention Second photo spacer height He ... holes PM1-PM3 ... photomasks PM4-PM6 ... photomasks PS-1, PS-1b, PS-1c, PS-1d, PS-1e of the present invention ... first photo spacer PS-2, PS-2b, PS-2c, PS-2d, PS-2e ... second photo spacer PS-11 ... first photo spacer in the present invention Sir PS-12 ... second photo spacer Px in the present invention ... one pixel region R1, R2 ... mask pattern region R11, R12 ... corresponding to the formation of a hole. Corresponding mask pattern region Re ... reflective display region Tr ... transmission display region ΔH ... height difference between the first photo spacer and the second photo spacer

Claims (6)

  In a photomask used when forming an optical path difference adjusting layer constituting a color filter for a transflective liquid crystal display device by a photolithography method using proximity exposure, a hole is formed at a predetermined portion on the upper surface of the optical path difference adjusting layer. Therefore, a photomask for a color filter, wherein a fine pattern is provided in a mask pattern region where a hole is to be formed.   2. The color filter photomask according to claim 1, wherein the fine pattern in the mask pattern region has a light-shielding portion having a circular or polygonal outer shape, and has a light-transmitting pattern at the center thereof.   2. The color filter photomask according to claim 1, wherein the fine pattern in the mask pattern region has a light-transmitting portion having an outer shape of a circle or a polygon, and has a light-shielding pattern at the center thereof. In the method for producing a color filter in which two types of photo spacers having different heights are simultaneously formed on the optical path difference adjusting layer,
1) When the optical path difference adjusting layer is formed, the photomask according to claim 1, 2, or 3 is used as a photomask, and a photo with a low height out of two types of photospacers having different heights is used. A hole is formed at the position of the upper surface of the optical path difference adjusting layer where the spacer (second photo spacer) is to be formed,
2) A method for producing a color filter, wherein when two types of photo spacers having different heights are simultaneously formed, a photo spacer having a low height (second photo spacer) is formed on the hole.   The method for producing a color filter according to claim 4, wherein the diameter or width of the hole is 3 to 8 μm.   A color filter for a transflective liquid crystal display device, which is manufactured by using the method for manufacturing a color filter according to claim 4 or 5.

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