JP4306385B2 - Substrate for liquid crystal display - Google Patents

Description

  The present invention relates to a color filter substrate for a transmissive liquid crystal display device, and more particularly to a color filter substrate in which a stripe made of a light shielding layer is provided at a pixel boundary.

  In recent years, liquid crystal display devices and plasma display devices have been put into practical use, and their mass production has been increasingly demanded.

  Along with this, production of liquid crystal display panels made of glass substrates on which color filters for liquid crystal display devices are formed and display panels made of glass substrates used for display panels for plasma display devices, etc. are also increased in size. It has become necessary to deal with mass production in Japan.

  Patterning by a photolithography method on a large-sized glass substrate is premised on projection exposure in terms of mass productivity and quality (yield surface), but has the following limitations and problems.

  (1) When patterning to a large glass substrate by direct exposure from the original plate (mask) at the same magnification, transfer exposure is required, a glass substrate for a large original plate is required. It is necessary to be an expensive low expansion glass substrate such as QZ (quartz glass), and good flatness (flatness) is required. Therefore, it has been difficult to obtain a glass substrate in the past because it is not an object of production.

  (2) In addition, it is basically difficult to produce a large-size original plate accurately and in a short time.

  In order to draw with high accuracy, an expensive drawing device such as an EB (electron beam) drawing machine for large size drawing that can accurately manage temperature and position accuracy is required, and drawing time is large because of the large size drawing. This leads to an increase in pattern drawing costs.

  (3) In the transfer by projection exposure, the original plate is fixed while holding the periphery thereof. Therefore, as the original plate becomes large, the bend (deflection) amount of the original plate due to its own weight increases, and the size is too large. It becomes difficult to obtain an appropriate transfer image.

  As the size of the original plate increases, it becomes difficult to maintain the gap between the original plate and the substrate to be exposed (glass substrate) within a range that can be used on the entire surface of the original plate, and there is a limit to increasing the size of the original plate.

  (4) When patterning a large glass substrate using a lens projection stepper and a mirror projection stepper, there is a problem that the throughput is low and the apparatus is expensive.

For this reason, conventionally, for example, an exposure apparatus as shown in FIG. 6 described in JP-A-9-127702, which employs a step exposure method and a proximity exposure (proximity exposure) method, is used. By proximity exposure (also referred to as proximity exposure), the position of the original and the large-sized glass substrate to be patterned is moved relatively, and the pattern of the original is shifted to perform exposure, that is, step exposure. .
JP, 9-127702, A This method is exposure which irradiates parallel light from the back of an original with a master and a large size glass substrate in the state where each surface becomes a horizontal direction and maintaining a predetermined gap. Although it is a method, the size of the original plate takes into account the influence of its deflection (also called vent).

  6A is a sectional view of the exposure apparatus, FIG. 6B is a schematic view of the top view as viewed from B1-B2 of FIG. 6A, and FIG. 7 is a light source. It is a schematic block diagram of a part.

  6 and 7, 600 is an exposure apparatus, 610 is a stage, 611 is an X drive unit, 612 is a Y drive unit, 613 is a Z drive unit, 614 is a θ drive unit, 615 is a substrate holding unit, and 615A is 3 points. A tilt adjustment unit, 615B is a substrate lift-up unit, 616 is a mask holding unit, 616A is a mask drop prevention, 620 is a glass substrate supply robot, 620A is a hand unit, 621 is a glass substrate discharging robot, 621A is a hand unit, 630 Is a glass substrate (workpiece), 640 is a mask (original), 650 is a light source unit, 650A is a light source, 670 is a gap sensor, 680 is a scope, 690 is an edge sensor, m1, m2, and m3 are reflectors, s is a shutter, l is a fly-eye lens.

  For easy understanding, the optical system is simplified or omitted in FIGS. 6A and 6B.

The exposure apparatus shown in FIG. 6 has a pair of X-direction movement masking apertures (also referred to as light-shielding plates) that are provided with an opening boundary parallel to the Y-direction on the horizontal plane and can move independently in the X-direction. 9 corresponds to 751 and 752 in FIG. (See Fig. 9 (a))
More specifically, the apparatus shown in FIG. 6 is capable of finely controlling the glass substrate 630 in the X, Y, Z axis directions and θ directions while holding the photosensitive material surface upward, and at least in the X, Y directions. A stage that can be moved by a predetermined distance in one direction, a mask holding unit 616 that holds the mask (original plate) 640 on the upper side of the glass substrate 630 with the mask surface down, and the back surface of the mask (original plate) 640 or the glass substrate 630 side A light source section 650 (details are shown in FIG. 6) for irradiating exposure light to the mask, and for exposing and transferring the pattern of the mask (original) 630 at a same magnification, shifting the exposure position a plurality of times. An exposure apparatus that automatically aligns the glass substrate 630 on the stage 610 with the mask (original) 640 and controls the exposure area by shielding the pattern area of the original. A light area control mechanism, and a Giyappu control mechanism for controlling the Giyappu the substrate and precursor.

  Then, the glass substrate 630 and the mask (original plate) 640 are brought close to each other, and the glass substrate 630 is stepped at a predetermined pitch in proximity exposure in which exposure is performed while maintaining a predetermined gap, and the mask is formed at a plurality of positions. (Original plate) The glass substrate 630 is exposed through the 640, and the pattern of the mask original plate 640 is transferred and exposed to the glass substrate 630.

  The mask (original plate) 640 has a size that allows the deflection during transfer to be within an allowable range.

Alternatively, the exposure apparatus shown in FIG. 6 is rotated so that the mask original plate and the surface of the glass substrate are along the vertical direction in consideration of the deflection due to the weight of the mask original plate as described in JP-A-09-141804. Thus, an exposure apparatus arranged as described above has been used.
In this case, the schematic configuration of the light source unit is as shown in FIG. 8. In practice, the exposure apparatus shown in FIG. 6 is actually used.

  Here, an example of the step exposure method from the original mask to the glass substrate will be briefly described with reference to FIG.

  First, at the first position, the glass substrate 730 and the mask 740 are controlled and aligned by the alignment mechanism and the gearup control mechanism described above, and after completing the gearup adjustment, the shutter of the light source unit (not shown) ), The light from the light source unit is taken in for a predetermined time, and the first exposure is performed to expose the entire pattern area of the mask 740 (equivalent to eight pattern areas 710).

  The latent image on the glass substrate 730 by the first exposure is as shown in FIGS.

  All the patterns 740A of the mask 740 in FIGS. 9A and 9A are transferred to the glass substrate side.

  Next, at the second position where the stage 110 is displaced in the X direction by a predetermined pitch, the alignment is performed again, and after completing the gap adjustment, a predetermined pattern 740A shown in FIGS. In the state of FIGS. 9A and 9B in which only the area is shielded by the masking apertures 751 and 752, light from the optical system is introduced for a predetermined time, and a partial area of the pattern 740A of the mask 740 (unit pattern) A second exposure is performed to expose four regions 710.

  The latent image on the glass substrate 730 by the second exposure is as shown in FIGS.

  Eventually, the latent images of the first exposure and the second exposure are combined as shown in FIGS. 9B and 9C, and the desired pattern 740B shown in FIG. 9C can be obtained.

  Reference numeral 710a is a developed image area 710 of a unit.

  In this way, an exposure method in which exposure is performed at each position while moving the stage stepwise to obtain a target latent image together is called a step exposure method.

  As the size of display panels is increasing, transmission-type liquid crystal display devices are increasingly required to improve their image quality, and the tolerances for local unevenness and streaks are becoming increasingly demanding. Accompanying this, by using a photolithographic method to a large-sized color filter substrate for a transmissive liquid crystal display device, the boundary between pixels formed of a grid-like black matrix or a linear black stripe, Quality improvement is also demanded in the patterning of the colored layer.

  Recently, it has been found that the effects of pixel boundaries cannot be ignored for local unevenness and streaks.

  Of course, the exposure of the patterning to the large color filter substrate by the photolithography method is a step exposure method using an apparatus as shown in FIG. 6 and an exposure method adopting a proximity exposure (proximity exposure) method. Exposure is performed at

  Since the liquid crystal display device has good visibility and is suitable for color display and moving image display, a TFT (Thin Film Transistor) is arranged in each pixel unit as an active element. In many cases, a drive type called a transmission type active matrix system (also referred to as a TFT drive system) for applying an independent voltage to light and darken the pixels and displaying images and text information is used. The color filter substrate has a cross-sectional structure as shown in FIG. 5, for example.

  As described above, the exposure for forming the black matrix by the photolithographic method on the glass substrate side on the color filter forming side for the liquid crystal display device is performed by a step exposure method using an apparatus as shown in FIG. Even in the case of performing exposure using an exposure method that adopts an exposure (proximity exposure) method, recently, there is a demand for a device that does not affect local unevenness and streaks.

  The light shielding pattern formed by connecting the patterns by such a step exposure method generates unevenness and streaks due to the connecting portions.

  This phenomenon is particularly a problem in a horizontal electric field type liquid crystal display device.

  The present invention, corresponding to this, is to provide a color filter substrate in a form in which local unevenness and streaks do not occur in a liquid crystal display device due to a stripe connecting portion formed of a light shielding layer. Specifically, even when a step exposure method and an exposure method adopting a proximity exposure (proximity exposure) method are used for exposure, and a stripe made of a light shielding layer is formed by a photolithographic method, the exposure joint portion The present invention is intended to provide a color filter substrate that does not cause local unevenness and streaks in a liquid crystal display device due to the above.

The substrate for a liquid crystal display device of the present invention is a substrate for a liquid crystal display device, wherein an opening that is continuous in the horizontal direction of the display region and a stripe that is also formed of a light shielding layer that is also continuous in the horizontal direction are vertically arranged in the display region. The stripes that are repeatedly arranged in the direction and each light-shielding layer has a first line having a predetermined line width, and the first line has the same line width as the first line, and is shifted from the first line in a direction orthogonal to the stripe direction. The arranged second line is connected by a connecting portion, and the connecting portion overlaps the first line and the second line in a direction perpendicular to the stripe direction. It is characterized by being arranged in a direction perpendicular to the direction of the stripes.

In the liquid crystal display substrate described above, each colored layer is arranged in the opening so as to be aligned in the vertical direction of the display area, and a strip-like stripe made of a light-shielding layer only in the horizontal direction is provided at the boundary of the pixel. And a color filter forming substrate in which pixels of each color are arranged in the vertical direction.
Further, in the liquid crystal display device substrate according to any one of the above, the patterning of the stripe formed of the light shielding layer is performed by a photolithography method, and the exposure for the patterning is a step exposure method, and The exposure method adopts a proximity exposure (proximity exposure) method, and is exposed in a direction perpendicular to the stripe direction and by a predetermined width so as to overlap in the line direction of the stripe. .

  Here, the vertical direction of the display area is a direction orthogonal to the horizontal direction of the display area.

(Function)
The substrate for a liquid crystal display device of the present invention is provided with such a configuration, thereby providing a color filter substrate in a form in which local unevenness and streaks in the liquid crystal display device due to the stripe connecting portion do not occur. It is possible.

  Specifically, the patterning of the stripe made of the light shielding layer is performed by a photolithography method, and the exposure for the patterning is an exposure method adopting a step exposure method and a proximity exposure (proximity exposure) method. In this case, when the exposure is performed in the direction orthogonal to the stripe direction and overlapped in the line direction of the stripe by a predetermined width, local unevenness and streaks in the liquid crystal display device due to the connection portion of the exposure are obtained. It is possible to provide a color filter substrate for a liquid crystal display device in which no occurrence occurs.

  As described above, the present invention makes it possible to provide a color filter substrate in a form in which local unevenness and streaks are not generated in the liquid crystal display device due to the stripe connecting portion formed of the light shielding layer.

  More specifically, exposure is performed even when exposure is performed by a step exposure method and an exposure method adopting a proximity exposure (proximity exposure) method, and a stripe made of a light shielding layer is formed by a photolithography method. It is possible to provide a color filter substrate in a form in which local unevenness and streaks are not generated in the liquid crystal display device due to the portion.

  In particular, the configuration including a stripe made of a light shielding layer, a colored layer having one or more bent portions between adjacent stripes, and a columnar spacer on the colored layer has unevenness and streaks due to the joint portion of the light shielding pattern. It is possible to provide a color filter substrate suitable for a horizontal electric field type liquid crystal display device that does not occur, has little viewing angle dependency, and does not generate gap unevenness.

  Embodiments of the present invention will be described with reference to the drawings.

  FIG. 1A is a schematic overall view of a substrate for a liquid crystal display device of the present invention, FIG. 1B is a view showing a part of a pixel portion (region without a connecting portion), and FIG. FIG. 2 is a diagram illustrating a state at a stripe connecting portion. FIG. 2 is a diagram for explaining an example of an embodiment of a method for patterning a stripe of a substrate for a liquid crystal display device according to the present invention. FIG. 2 shows the exposure area of the original in the first exposure, FIG. 2A2 shows the latent image formation state by the first exposure, FIG. 2B1 shows the exposure area of the original in the second exposure, and FIG. (B2) shows a latent image formation state by the second exposure, and FIG. 2 (c) is a partially enlarged view of the area A1 including the boundary between the first exposure and the second exposure in FIG. 2 (b2). FIG. 3 is a view showing an exposure state (latent image state) in the patterning of the stripe of the first comparative example. 1, 2, and 3, 10 is a substrate for a liquid crystal display device (color filter substrate), 11 is a substrate, 15 is a display region (also referred to as a pixel region), 20 is a stripe, 25 is a connecting portion, and 30 is a pixel. , 31 is an R colored pixel portion, 32 is a G colored pixel portion, 33 is a B colored pixel portion, 40 is a colored layer, 41 is an R colored layer, 42 is a G colored layer, 43 is a B colored layer, 110 is an original plate, 111 Is a pattern portion, 112 is a light shielding portion, 120 is a substrate (for a color filter substrate), 121 is a latent image by a first exposure, 121A is a stripe pattern latent image (by a first exposure), and 122 is a second exposure. , 122A is a stripe pattern latent image (by the second exposure), 125 is a boundary portion (between the first exposure region and the second exposure region), 131 and 132 are masking apertures, and 221 is (the first exposure region) By exposure) Ripe pattern latent image, 222 (the second exposure) stripe pattern latent image, [alpha] 1, [alpha] 2 is a pattern shift.

  An example of an embodiment of a substrate for a liquid crystal display device of the present invention will be described with reference to FIG.

  The substrate 10 for the liquid crystal display device of this example is a color filter substrate for a transmissive liquid crystal display device, and has an R colored layer 41, G in the vertical direction of the display region 15 (the display region short side direction in FIG. 1A). The colored layer 42 and the B colored layer 43 are respectively arranged in a band shape, and a band-like stripe 20 made of a light shielding layer is provided only in the lateral direction perpendicular to the colored layer at the boundary portion of the pixel 30, and FIG. As shown in FIG. 4, the pixels having long shapes in the vertical direction are arranged, and aligned in the vertical direction orthogonal to the direction of the stripes 20, each stripe 20 has a predetermined width L and overlaps in the line direction. A connecting portion 25 (shown in FIG. 1C) is provided.

  In the liquid crystal display substrate 10 of this example, the patterning of the stripe 20 made of a light shielding layer is performed by a photolithography method, and the exposure for the patterning is a step exposure method and proximity exposure (proximity exposure). ) In an exposure method adopting the method, the exposure is performed by overlapping the stripe 20 in the line direction by a predetermined width in a direction orthogonal to the stripe direction.

  In such an exposure method, they are exposed and patterned in an overlapping manner, and an exposure shift occurs in the joint portion, and after development processing or development processing and etching processing, it is shown in FIG. In this way, the stripe is thicker than the other portions only by the portion of the predetermined width L.

  A glass substrate is usually used as the substrate, but is not limited to this as long as it has good properties such as transmittance and thermal expansion, processability, and resistance.

  The stripe 20 formed of the light shielding layer is usually formed by patterning chromium, chromium oxide, chromium nitride, chromium oxynitride, or a metal layer in which these layers are laminated by photolithography, and further etching, or a black photosensitive material. Is applied and a pattern is formed by photolithography.

  The R colored layer 41, the G colored layer 42, and the B colored layer 43 are formed by dyeing, forming a pigment-dispersed photosensitive material by plate making, printing, electrodeposition, or the like, and are not particularly limited.

  The substrate 10 for a liquid crystal display device of this example is preferably used as a color filter substrate for a liquid crystal display device of a horizontal electric field type.

  In a color filter substrate for a horizontal electric field type liquid crystal display device, a negative photosensitive resin containing titanium oxide as a black pigment is preferable as a stripe material made of a light-shielding layer because the shift of the pattern of the joint portion is not noticeable.

  In the case of this method, the colored layer having one or more bent portions between adjacent stripes made of the light shielding layer preferably has an angle substantially the same as the bent angle of the electrode of the active element side substrate.

  The columnar spacer may be on the opening, but is preferably formed on a stripe made of a light shielding layer.

  It is further preferable to provide a planarization protective layer on the colored layer and form a columnar spacer thereon.

  The columnar spacer is for controlling a gap when sealing the liquid crystal and after sealing.

  As a method of arranging colored layers of the same color in the vertical direction, all three colors can be strip-like, all three colors can be independent patterns, and any of the above arrangements can be used.

  An exposure method in the patterning of the stripe of the substrate 10 for the liquid crystal display device of this example will be described with reference to FIG.

  The patterning for forming stripes is performed by photolithography, and the exposure method is a step exposure method and an exposure method adopting a proximity exposure (proximity exposure) method. Is what you do.

  Then, a desired pattern is formed on the substrate 120 using the original 110 having the pattern area 111 smaller than the desired pattern area formed on the substrate 120. First, the entire pattern area of the original is exposed first. Next, the stage 610 shown in FIG. 6 is moved, and the exposure range is limited by the masking apertures 131 and 132 while the original 110 is fixed at the same position as the first exposure position. The second exposure is performed on the predetermined exposure region by overlapping the partial exposure regions.

  In this case, the exposure for overlapping the region to be the connecting portion is to overlap the stripe line direction by a predetermined width OL1, and the A1 portion shown in FIG. 2 (b2) is as shown in FIG. 2 (c). .

  In this case, assuming that the shift amount between the stripe pattern latent image 121A and the stripe pattern latent image 122A is α1, when the stripe is formed through the development process or the development process and the etching process, the reduction rate of the transmitted light in this overlap region is If the line width and pitch of the stripe pattern are W1 and P1, respectively, α1 / (P1−W1).

  On the other hand, as a first comparative example, a color filter substrate for a transmissive liquid crystal display device, an R colored layer 41 and a G colored layer in the vertical direction of the display region 15 (short direction of the display region 15 in FIG. 1A). 42 and the B colored layer 43 may be arranged in a strip shape, and a striped stripe made of a light shielding layer may be provided at the pixel boundary only in the direction along the colored layer.

  Also in this case, as in the embodiment shown in FIG. 1, it is assumed that patterning is performed. When exposure is performed so as to overlap by a predetermined width OL2 in the direction orthogonal to the line direction of the stripe pattern, the overlapping of the latent images is as shown in FIG. As shown in FIG. 2, when the amount of deviation between the stripe pattern latent image 221 by the first exposure and the stripe pattern latent image 222 by the second exposure is α2, stripes are formed through development processing or development processing and etching processing. In this case, the reduction rate of the transmitted light in the overlap region is α2 / (P2−W2) if the line width and pitch of the stripe pattern are W2 and P2.

  Here, if W1 = W2, P1 = P2, and α1 = α2, there is no difference between the exposure method of this example and the comparative example for obtaining the latent image shown in FIG. After the image is formed, the development process, or the development process and the etching process are further performed, and the patterned stripe-formed substrate and the color filter substrate on which the colored layer is further formed are transmitted using a light table. When visual inspection is performed, unevenness and streaks are much better in the color filter substrate of this example than in the first comparative example.

  In the visual inspection, the stripe direction is the vertical direction of the liquid crystal display device, and the longitudinal direction of the pixel is the vertical direction to be seen by a person, and such a result seems to be obtained from human visual characteristics. .

  As another example of the pixel boundary shape of the color filter substrate, a color filter substrate for a transmissive liquid crystal display device having a black matrix composed of a light shielding layer in a lattice shape located at the boundary of each colored layer. As a second comparative example.

  This is a configuration in which the stripes of the embodiment and the stripes of the first comparative example are provided together and are formed in a lattice pattern at the boundary of the pixels.

  As for the second comparative example, the visual inspection method using the light table described above is inferior in terms of unevenness and streaks as compared with the first embodiment, as in the case of the first comparative example. was gotten.

In addition, as an original mask, exposure drawing is carried out by an exposure apparatus that performs exposure using data on a dry plate of a predetermined size, a light shielding film such as chromium, a glass substrate substrate in which a photosensitizer is arranged in this order, and developed. Developed, etched and patterned (also referred to as the original), or transferred from the original to a glass substrate substrate in which another dry plate, a light shielding film such as chromium, and a photosensitizer are arranged in this order by contact exposure A patterning process (also called a copy) is used at least once.

FIG. 1A is a schematic overall view of a substrate for a liquid crystal display device of the present invention, FIG. 1B is a view showing a part of a pixel portion (region without a connecting portion), and FIG. It is the figure which showed the state in the connection part of a stripe. FIG. 2 is a diagram for explaining an example of an embodiment of a stripe patterning method for a substrate for a liquid crystal display device according to the present invention. FIG. 2 (a1) shows an exposure area of the original in the first exposure. 2 (a2) shows the latent image formation state by the first exposure, FIG. 2 (b1) shows the exposure area region of the original in the second exposure, and FIG. 2 (b2) shows the latent image formation by the second exposure. FIG. 2 (c) is a partially enlarged view of the region A1 including the boundary between the first exposure and the second exposure in FIG. 2 (b2). It is the figure which showed the exposure state (latent image state) in the patterning of the stripe of the 1st comparative example. 1 is a cross-sectional view illustrating a cross-sectional structure of a liquid crystal display device of a driving method called a transmissive active matrix method (also referred to as a TFT driving method). . FIG. 5 is a cross-sectional view illustrating an example of a cross-sectional structure of a color filter substrate in the liquid crystal display device illustrated in FIG. 4. 6A is a cross-sectional view of the exposure apparatus, and FIG. 6B is a schematic view of a top view as viewed from B1-B2 of FIG. 6A. It is a schematic block diagram of a light source part. It is a schematic block diagram of a light source part. It is a figure for demonstrating the exposure method to a glass substrate from an original mask.

Explanation of symbols

10 Liquid crystal display substrate (color filter substrate)
11 Substrate 15 Display area (also referred to as pixel area)
20 stripe 25 connecting part 30 pixel 31 R colored pixel part 32 G colored pixel part 33 B colored pixel part 40 colored layer 41 R colored layer 42 G colored layer 43 B colored layer 110 original plate 111 pattern part 112 light shielding part 120 (color filter substrate) Substrate 121 for first exposure latent image 121A stripe pattern latent image 122 (by first exposure) 122 latent image 122A by second exposure stripe pattern latent image 125 (by second exposure) (first exposure region) Boundary 131, 132 masking aperture 221 Stripe pattern latent image 222 (by first exposure) Stripe pattern latent image α1, α2 Pattern shift (by second exposure)

Claims (3)

A substrate for a liquid crystal display device, wherein openings that are continuous in the horizontal direction of the display area and stripes that are also formed of light shielding layers that are also continuous in the horizontal direction are repeatedly arranged in the vertical direction of the display area. The resulting stripe has a first line having a predetermined line width, and a second line having the same line width as the first line and being shifted from the first line in a direction perpendicular to the stripe direction . The connecting portion is connected by a connecting portion, and the connecting portion is formed by overlapping the first line and the second line by shifting in a direction orthogonal to the stripe direction, and orthogonal to the stripe direction. A substrate for a liquid crystal display device, characterized by being aligned in a direction.   2. The substrate for a liquid crystal display device according to claim 1, wherein each colored layer is arranged in the opening so as to be aligned in the vertical direction of the display region, and a strip-like stripe made of a light shielding layer is formed only in the horizontal direction. A substrate for a liquid crystal display device, characterized in that it is a color filter forming substrate provided at a border and having pixels of each color arranged in a vertical direction. A substrate according to any one of claims 1-2, patterning of stripes made of a light-shielding layer has been made by photolithography, exposure for the patterning step exposure method In addition, the exposure method adopts a proximity exposure (proximity exposure) method, and is exposed in a direction perpendicular to the stripe direction and by a predetermined width so as to overlap the stripe line direction. A substrate for a liquid crystal display device.

Images