CN101246285A - Method for manufacturing photosensitive spacer - Google Patents

Abstract

The invention discloses a method for manufacturing photosensitive spacers, which comprises the steps of firstly forming a black matrix substrate with a plurality of spacers and openings of a color layer on a transparent substrate by utilizing a photoetching process, then forming a color filter layer on the black matrix substrate, and then forming a transparent conducting layer on the black matrix substrate and the color filter layer. Then coating photosensitive spacing material on the transparent conducting layer, directly using black matrix as mask to make back exposure cross-linking process, radiating UV ray from lower portion of transparent base plate, and making the UV ray pass through the spacer open region of black matrix to define pattern, making the photosensitive spacing material be cross-linked, developing and baking so as to form the spacer layer.

Description

Method for making photosensitive spacers

technical field

The invention relates to a method for making a photosensitive spacer of a flat panel display, and in particular to a method for making an ultra-high resolution photosensitive spacer.

Background technique

The color filter is the key component of the colorization of the liquid crystal display. Through the processing of the color filter, the strong light emitted by the LCD backlight module can be displayed in a colorful picture. The production of the color filter is to make a black matrix on the glass substrate to form intervals, and then arrange the three primary colors of red, green and blue in each pixel of the colorization layer in sequence. The black matrix and the colored layer are made by using photosensitive material with yellow light lithography process.

The main function of the spacer is to maintain the distance between the upper and lower glass substrates of the liquid crystal display, forming a space to fill the liquid crystal. The current spacers are mainly rod-shaped or spherical particles of silicon oxide, plastic, and glass, which are filled between the upper and lower glass substrates of the LCD in a dispersed manner. However, if the spacers are poorly spread, the contrast value of the screen display will change, and even the viewing angle will be affected. Therefore, with the trend of increasing the size of the substrate, the uniformity of the spacers becomes more and more important.

Therefore, a manufacturing method has been developed to integrate the spacers on the substrate. Using the yellow light process to form the bumps of the spacers can not only increase the light transmittance and reduce the generation of light leakage, but also prevent the spacers from being affected by the glass substrate. Particle rupture defects caused by pressure.

With the popularization of liquid crystal display panel applications, the requirements for resolution are gradually increasing. The resolution of LCD depends on the number of pixels. The more pixels, the more detailed the picture will be, and the better the color expression will be. However, the higher number of pixels means that the area of the color layer in the matrix must be increased, and therefore the line width of the black matrix portion used to define the area and the photosensitive gap sub-section above it must also be reduced.

At present, the yellow light lithography process of TFT-LCD color filters mostly uses a proximity aligner with fast production speed and low price for pattern transfer and exposure, but the pattern transfer mask used by the proximity aligner There is a distance of 50-500 μm between the die and the photosensitive material. Due to the influence of light diffraction, it is difficult to achieve a fine line width, and the volume of the produced spacer cannot meet the actual requirements. At present, the feasible method is to use high-end equipment such as a variable depth of focus (depth of focus) exposure machine, or to achieve the purpose of miniaturization through material adjustment, but capital expenditure must be increased.

Contents of the invention

Therefore, the present invention is to provide a method for manufacturing photosensitive spacers of flat panel displays, which is used to improve the problem that the traditional manufacturing method is limited by the diffraction effect of light, and the particle size of photosensitive spacers cannot meet the miniaturization requirement.

According to the above features of the present invention, a method for making photosensitive spacers is proposed, which uses back exposure to eliminate the diffraction effect of light reaching the photosensitive material, and achieves the purpose of miniaturizing the spacers.

Firstly, a black matrix with a plurality of spacer openings and a plurality of color layer openings is formed on a transparent substrate by using a photolithography process to form a black matrix substrate. Then, use color photosensitive materials to form red, green, and blue color filter layers on the black matrix substrate, and coat a layer of transparent conductive material on the black matrix substrate and the color filter layer to form a transparent conductive material. layer. Finally, the photosensitive spacer material is coated on the transparent conductive layer, and the back exposure crosslinking process is directly performed using the black matrix as a mask. Ultraviolet rays are irradiated from the bottom of the transparent substrate, and the photosensitive spacer material is crosslinked through the black matrix, and then developed and baked. After the baking step, the interstitial sub-layer is formed, which can reduce the difference between the upper and lower bottom of the interstitial sub-layer, so as to produce the interstitial sub-layer with a smaller particle size.

In order to make the constitutional features, operation method, purpose and advantages of the present invention easier to understand, the embodiments of the present invention are described below in conjunction with the accompanying drawings and text descriptions.

Description of drawings

In order to make the above and other objects, features, advantages and embodiments of the present invention more comprehensible, the detailed description of the accompanying drawings is as follows:

FIG. 1 shows a flow chart of the steps of making photosensitive spacers according to an embodiment of the present invention;

FIG. 2 shows a schematic diagram of the steps of manufacturing a black matrix substrate according to an embodiment of the present invention;

Fig. 3 shows the top view of the black matrix substrate made according to the method of the present invention;

Fig. 4 shows a schematic diagram of the steps of making a color filter layer according to an embodiment of the present invention;

Fig. 5 shows the top view of the black matrix substrate with color filter layer made according to the method of the present invention;

FIG. 6 shows a schematic diagram of the steps of making a gap sublayer according to an embodiment of the present invention;

Fig. 7 shows a flow chart of the steps of making photosensitive spacers according to another embodiment of the present invention;

FIG. 8 shows a schematic diagram of the steps of manufacturing a black matrix substrate according to another embodiment of the present invention;

9A-9B are schematic diagrams comparing the back exposure method of the present invention with the traditional front exposure method.

Among them, reference signs:

110: Steps

112: Steps

114: Steps

116: Steps

118: Steps

210: transparent substrate

221: black matrix

223: gap opening

240: light source

410: The first color photosensitive material

412: second color filter layer

421: First mask

423: Third mask

600: transparent photoresist layer

711: Steps

713: Steps

715: Step

717: Steps

719: Steps

821: black metal film

823: Patterned photoresist layer

830: mask

850: color layer opening

911: Black Matrix

921: transparent photoresist layer

931: transparent substrate

941: light source 111: steps

113: Steps

115: Steps

117: Steps

119: Steps

220: Black photoresist layer

222: color layer opening

230: mask

400: black matrix substrate

411: the first color filter layer

413: the third color filter layer

422: second mask

430: transparent conductive layer

610: Gap Subcolumn

712: Step

714: Step

716: Step

718: Steps

810: transparent substrate

822: positive photoresist layer

824: black metal film matrix

840: light source

910: mask

920: transparent photoresist layer

930: Substrate

940: light source

Detailed ways

Please refer to FIG. 1 , which shows a flow chart of the steps of manufacturing a photosensitive spacer according to an embodiment of the present invention, and refer to FIG. 2 , which is a schematic diagram of the steps of manufacturing a black matrix substrate according to an embodiment of the present invention.

First, as shown in step 110 and FIG. 2 , a photosensitive black light-shielding material is coated on a transparent substrate 210 to obtain a black photoresist layer 220 with uniform thickness. According to an embodiment of the present invention, the photosensitive black light-shielding material can be evenly coated on the transparent substrate 210 by a suitable method, such as a spin coating method. The transparent substrate 210 can be a glass substrate, and the photosensitive black light-shielding material can be an alkali-soluble black photoresist material, which is a negative photoresist material, and the light-shielding material in the photoresist can be carbon black particles or metal particles, such as titanium oxide.

Next, as shown in step 111 and FIG. 2 , a mask 230 is provided to form a black matrix. Wherein, the mask 230 has a plurality of gap sub-opening areas and a plurality of color layer opening areas, and the shape of the gap sub-opening areas can be any shape, such as polygonal, circular, elliptical and so on. A light source 240 irradiates ultraviolet rays on the black photoresist layer 220 through the mask 230 to perform an exposure cross-linking (cross-link) process, and the part of the black photoresist layer 220 irradiated by ultraviolet rays can form a cross-linked structure.

As shown in step 112 , the cross-linked black photoresist layer 220 is developed with a slightly alkaline developer solution to define the pattern of the mask 230 on the transparent substrate 210 . After the photoresist is irradiated, the original chemical properties are changed, so that the dissolution rates of the irradiated area and the non-irradiated area in the developer are not equal, and the developer can dissolve the easily soluble area, and the black photoresist layer 220 The uncrosslinked part can be removed from the transparent substrate 210 to achieve the purpose of developing.

After that, hard bake is carried out to remove residual moisture or solvent, and to increase its adhesion and flatness. As shown in step 113 , after hard-baking, a patterned black matrix 221 can be formed and attached to the transparent substrate 210 to form a black matrix substrate.

Please refer to FIG. 3 , which is a top view of the black matrix. The black matrix 221 has a plurality of color layer openings 222 and a plurality of gap sub-holes 223 , wherein the shape of the gap sub-holes 223 can be any shape, such as polygon, circle, ellipse and so on.

Next, as shown in step 114 , a color filter layer is formed on the black matrix substrate. And referring to FIG. 4 , it shows a schematic diagram of steps of manufacturing a color filter layer according to an embodiment of the present invention. Firstly, the first color photosensitive material 410 is coated on the black matrix substrate 400 , and the light source 240 is used to generate ultraviolet rays, which are irradiated on the first color photosensitive material 410 through the first mask 421 . The first mask 421 has a plurality of openings of the first color layer, through which light can pass through the openings of the first color layer to perform an exposure and cross-linking process.

The cross-linked first color photosensitive material 410 is then developed and hard-baked to form a first color filter layer 411 . Afterwards, similarly to the above steps, the second and third color photosensitive materials are exposed, cross-linked and developed using the second mask 422 and the third mask 423 in sequence. The second mask 422 and the third mask The mold 423 has a plurality of second color layer opening areas and third color layer opening areas respectively, and can form the second color filter layer 412 and the third color filter layer 413. After the above steps are completed in sequence, a layer with RGB Three-color color filter layer. Wherein, the first color photosensitive material, the second color photosensitive material and the third color photosensitive material are all negative photoresist materials, and the positions of the opening regions of the color layers of the above three different masks do not overlap each other.

)之间。形成透明导电层430的透明导电材料可包含氧化铟锡(In₂O₃/SnO₂)、二氧化锡(SnO₂)、三氧化二铟(In₂O₃)或氧化锌(ZnO)。Next, referring to FIG. 1 and FIG. 4 , as shown in step 115 , a transparent conductive layer 430 is formed on the black matrix substrate 400 and the color filter layer. Wherein, the transparent conductive layer 430 is formed by sputtering or vapor deposition, and its thickness can be between 1400 angstroms-1600 angstroms (

)between. The transparent conductive material forming the transparent conductive layer 430 may include indium tin oxide (In ₂ O ₃ /SnO ₂ ), tin dioxide (SnO ₂ ), indium trioxide (In ₂ O ₃ ) or zinc oxide (ZnO).

Please refer to FIG. 5 , which is a top view of a black matrix substrate with a color filter layer. There may be multiple first color filter layers 411, second color filter layers 412 and third color filter layers 413 on the black matrix substrate 400, as well as multiple gap sub-holes 223, wherein the gap sub-holes 223 The shape can be any shape, such as polygon, circle, ellipse, etc.

Next, as shown in step 116 and FIG. 6 , FIG. 6 is a schematic diagram of the formation of the gap sublayer. First, the photosensitive spacer material is coated on the transparent conductive layer 430 to obtain a transparent photoresist layer 600 with a uniform thickness. The material of the transparent photoresist layer 600 can be a transparent photosensitive resin.

Next, using the pattern of the black matrix substrate 400 as a mask of the transparent photoresist layer 600, the light source 240 irradiates from the back of the transparent substrate, and through the pattern of the black matrix 400, irradiates ultraviolet rays on the transparent photoresist layer 600 for exposure. For cross-linking, the part of the transparent photoresist layer 600 irradiated with ultraviolet rays can form a cross-linked structure, and then develop and hard-bake to form gap sub-pillars 610 . Wherein, the particle size of the spacer columns 610 can be determined by the spacer openings 223 defined by the black matrix substrate 400 , and the height of the spacers can be between 0.1 μm and 10 μm. According to an embodiment of the present invention, the height of the spacers can be between 2.5-5 μm, and the difference between the upper and lower bases can be between 0.1-20 μm.

Please refer to FIG. 7 , which shows a flowchart of the steps of manufacturing photo spacers according to another embodiment of the present invention, and refer to FIG. 8 , which is a schematic diagram of steps of manufacturing a black matrix substrate according to another embodiment of the present invention.

First, as shown in step 711 and FIG. 8, a black metal film 821 is plated on a transparent substrate 810. According to an embodiment of the present invention, the transparent substrate 810 can be a glass substrate, and the black metal film can be formed by an appropriate method, such as evaporation. The transparent substrate 810 is evenly plated on the transparent substrate 810 by plating or sputtering. The black metal film can be a chrome film, a nickel film, or the like. As shown in step 715 , a positive photosensitive material is coated on the black metal film 821 to obtain a positive photoresist layer 822 with a uniform thickness.

Next, as shown in step 713 and FIG. 2 , a mask 830 is provided to form a black matrix. Wherein, the mask 830 has a plurality of gap sub-opening areas and a plurality of color layer opening areas, and the shape of the gap sub-opening areas can be any shape, such as polygon, circle, ellipse and so on. A light source 840 irradiates ultraviolet light on the positive photoresist layer 822 through the mask 830 to perform a chain scission process.

As shown in step 714 , the positive photoresist layer 822 is developed with a developing solution to define the pattern of the mask 830 on the transparent substrate 810 . After the photoresist is irradiated, the original chemical properties are changed, so that the dissolution rates of the irradiated area and the non-irradiated area in the developer are not equal, and the developer can dissolve the easily soluble area, and the positive photoresist layer 822 The exposed portion can be removed from the transparent substrate 210 to achieve the purpose of development and form a patterned photoresist layer 823 .

As shown in step 715, a baking process is performed to remove residual moisture or solvent, and to increase its adhesion and flatness. The baked patterned photoresist layer 823 is attached to the transparent substrate 810 to complete a matrix pattern on the black metal film.

Next, as shown in step 716 , using the patterned photoresist layer 823 as an etching barrier layer, the black metal film 821 is etched to form a black metal film matrix 824 with spacer openings 850 .

As shown in step 717 , the patterned photoresist layer 823 above the black metal film matrix 824 is removed, and then as shown in step 718 , a black matrix substrate with spacer openings and color layer openings is formed.

Afterwards, as shown in step 719 , a color filter layer is formed using the method shown in FIG. 1 and FIG. 4 , and gap sub-pillars are formed by a back exposure method. Please refer to FIG. 9A to FIG. 9B , which are schematic diagrams comparing the back exposure method and the front exposure method of the present invention.

FIG. 9A is a front exposure method. A transparent photoresist layer 920 is attached to a substrate 930. By front exposure, the pattern on the mask 910 is transferred to the transparent photoresist layer 920 by a proximity alignment exposure machine. To avoid mask contamination, there must be a distance of 50-500 μm between the mask 910 and the transparent photoresist layer 920 (here, 100 μm is taken as an example). However, the diffraction effect of the light from the light source 940 reaching the photosensitive material will enlarge the area of the exposed photoresist (as shown by the dotted arrow), and the final formed spacer cannot approach the ideal rectangular columnar shape, but presents a trapezoidal shape. The area of the lower bottom is much larger than that of the upper bottom, causing the particle size of the interstitial particles to become larger, which does not meet the requirements of miniaturization.

Referring to FIG. 9B again, it is the backside exposure method of the present invention. First, the black matrix 911 is fixed on a transparent substrate 931 by the steps shown in FIG. 1 to form a black matrix substrate, and then the transparent photoresist layer 921 is coated on On the black matrix substrate, the light source 941 is used to expose the pattern defined by the black matrix 911 as a mask, and the light is irradiated from the back of the transparent substrate 931 to the transparent photoresist layer 921 for cross-linking. Because the black matrix 911 has been fixed on the transparent substrate 931, not only can reduce the use of a mask, but also shorten the distance between the light to reach the transparent photoresist layer 921, effectively eliminate the diffraction effect of light, the upper layer of the photoresist The exposed area is only slightly increased compared to the bottom layer (as indicated by the dotted arrow). Furthermore, due to the development effect, the upper base will be slightly reduced, so the gap between the lower base and the upper base of the final formed spacer is very small, which can be close to the ideal rectangular columnar shape, and the particle size of the spacer can be controlled within the required range. , to meet the requirements of miniaturization, and then increase the total area of the color filter layer and the number of R, G, and B filter areas included, and improve the resolution and color performance of the liquid crystal panel.

As can be seen from the preferred embodiments of the present invention described above, the application of the present invention has the following advantages:

Firstly, high-resolution spacers can be produced by applying the method of the present invention. In the present invention, the black matrix preformed on the transparent substrate is used as a mask for making the spacers, and then the photosensitive material of the spacers is cross-linked through back exposure, which can improve the accuracy of exposure alignment and shorten the time between light rays reaching the photosensitive material. The distance between them can effectively eliminate the diffraction effect of light, form spacers close to the ideal particle size, and reduce the use of masks.

In addition, compared with scanning equipment, the cost of applying the method of the present invention is also lower, and the material does not need to be specially designed, and can be connected with existing technologies.

Therefore, applying the method of the present invention to make spacers can be suitable for manufacturing high-order high-resolution AV displays, high-resolution handheld mobile phone display screens, thin-film transistor (TFT) liquid crystal displays, low-temperature polysilicon (LTPS) liquid crystal displays, ultra- Devices such as twisted liquid crystal displays, organic light-emitting diodes (OLEDs) and plasma flat-panel displays can provide products with higher resolution and color performance capabilities.

Although the present invention has been described with the above-mentioned embodiments, it is not intended to limit the present invention. Any person skilled in the art can make various improvements and changes to the present invention without departing from the spirit and scope of the present invention. Accordingly, the protection scope of the present invention is defined by the appended claims.

Claims (20)

1. A method for making photosensitive spacers, characterized in that the method comprises: providing a transparent substrate; A mask is provided for making a black matrix, and the mask has a plurality of gap sub-opening areas and a plurality of color layer opening areas; Using the mask to form a black matrix substrate with a plurality of spacer openings and a plurality of color layer openings; forming a color filter layer on the black matrix substrate; forming a transparent conductive layer on the black matrix substrate and the color filter layer; Coating a photosensitive spacer material on the transparent conductive layer; Using the black matrix substrate as a mask, irradiating ultraviolet light on the photosensitive spacer material through the transparent substrate, and performing a backside exposure cross-linking process; developing the crosslinked photospacer; and The developed photo spacer material is baked to form a spacer sublayer. 2. The method for making photosensitive spacers according to claim 1, wherein the transparent substrate is a glass substrate. 3. The method for making photosensitive spacers according to claim 1, wherein the step of forming a black matrix substrate comprises at least: coating a photosensitive black light-shielding material on the transparent substrate; irradiating ultraviolet light on the photosensitive black light-shielding material through the mask to perform an exposure cross-linking process; developing the crosslinked photosensitive black opacifying material; and The developed photosensitive black light-shielding material is baked to form a black matrix substrate. 4. The method for making a photosensitive spacer according to claim 3, wherein the photosensitive black light-shielding material is an alkali-soluble black photoresist material. 5. The method for making photosensitive spacers according to claim 4, wherein the alkali-soluble black photoresist material comprises carbon black particles or metal particles. 6. The method for making photosensitive spacers according to claim 5, wherein the metal particles comprise titanium oxide. 7. the method for making photosensitive spacer according to claim 3, is characterized in that, the black photoresist material of this cross-linking utilizes slightly alkaline developing solution to develop. 8. The method for making photosensitive spacers according to claim 1, wherein the step of forming a black matrix substrate at least comprises: Coating a black metal film on the transparent substrate; Coating a positive photosensitive material on the black metal film; irradiating ultraviolet light on the positive photosensitive material through the mask to perform an exposure bond breaking process; developing the positive photosensitive material to form a patterned photoresist; baking the patterned photoresist; using the patterned photoresist as a mask to etch the black metal film; and The patterned photoresist is removed to form a black matrix substrate. 9. The method for making photosensitive spacers according to claim 8, characterized in that the method for coating the black metal film comprises evaporation or sputtering. 10. The method for making a photosensitive spacer according to claim 8, wherein the ferrous metal film comprises a chromium film or a nickel film. 11. The method for fabricating photosensitive spacers according to claim 1, wherein the shape of the opening area of the spacer comprises a polygon, a circle or an ellipse. 12. The method for making photosensitive spacers according to claim 1, wherein the step of forming a color filter layer at least comprises: Coating a first color photosensitive material on the black matrix substrate; irradiating ultraviolet light on the first color photosensitive material through a first mask to perform an exposure crosslinking process, the first mask has a plurality of first color layer openings; developing the crosslinked first color photosensitive material; baking the developed first color photosensitive material to form a first color filter layer; Coating a second color photosensitive material on the black matrix substrate; irradiating ultraviolet light on the second color photosensitive material through a second mask to perform an exposure crosslinking process; developing the crosslinked second color photosensitive material; baking the developed second color photosensitive material to form a second color filter layer; coating a third color photosensitive material on the black matrix substrate; irradiating ultraviolet light on the third color photosensitive material through a third mask to perform an exposure cross-linking process; developing the crosslinked third color photosensitive material; and The developed third color photosensitive material is baked to form a third color filter layer. 13. The method for making photosensitive spacers according to claim 12, wherein the second mask has a plurality of second color layer openings, and the positions of the second color layer openings are the same as those of the first The open areas of the colored layers do not overlap. 14. The method for making photosensitive spacers according to claim 12, characterized in that, the third mask has a plurality of third color layer openings, the positions of the third color layer openings are the same as those of the first color The opening area of the layer and the opening area of the second colored layer do not overlap. 15. The method for making photosensitive spacers according to claim 1, wherein the material of the transparent conductive layer is a transparent conductive material. 16. The method for producing a photosensitive spacer according to claim 15, wherein the transparent conductive material comprises indium tin oxide (In ₂ O ₃ /SnO ₂ ), tin dioxide (SnO ₂ ), diindium trioxide (In ₂ O ₃ ) or zinc oxide (ZnO). 17. The method for making photosensitive spacers according to claim 1, wherein the thickness of the transparent conductive layer is between 1400 angstroms and 1600 angstroms. 18. The method for making a photosensitive spacer according to claim 1, wherein the photosensitive spacer material is a transparent photosensitive resin. 19. The method for manufacturing photosensitive spacers according to claim 1, characterized in that the height of the formed spacer layer is between 0.1 micron and 10 microns, preferably the height of the spacer layer is 1.5-3.5 microns. 20. The method for producing photosensitive spacers according to claim 1, wherein the gap between the upper and lower sides of the formed spacer layer is between 0.1 microns and 20 microns.

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