CN109960073B - Method for manufacturing color filter layer - Google Patents
Method for manufacturing color filter layer Download PDFInfo
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- CN109960073B CN109960073B CN201711435025.4A CN201711435025A CN109960073B CN 109960073 B CN109960073 B CN 109960073B CN 201711435025 A CN201711435025 A CN 201711435025A CN 109960073 B CN109960073 B CN 109960073B
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- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour
- G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on liquid crystals, e.g. single liquid crystal display cells
- G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
- G02F1/1333—Constructional arrangements; Manufacturing methods
- G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
- G02F1/133509—Filters, e.g. light shielding masks
- G02F1/133512—Light shielding layers, e.g. black matrix
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- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour
- G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on liquid crystals, e.g. single liquid crystal display cells
- G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
- G02F1/1333—Constructional arrangements; Manufacturing methods
- G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
- G02F1/133509—Filters, e.g. light shielding masks
- G02F1/133514—Colour filters
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- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour
- G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on liquid crystals, e.g. single liquid crystal display cells
- G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
- G02F1/1333—Constructional arrangements; Manufacturing methods
- G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
- G02F1/133509—Filters, e.g. light shielding masks
- G02F1/133514—Colour filters
- G02F1/133516—Methods for their manufacture, e.g. printing, electro-deposition or photolithography
Abstract
A method for manufacturing a color filter layer comprises the following steps: forming a black matrix layer on a transparent substrate, the black matrix layer having a plurality of openings; forming a first color photoresist layer in the first number of openings, wherein the first color photoresist layer fills the openings and has an overlapping part covering the black matrix layer; exposing the first color photoresist material layer by using a first photomask as a mask; the first photomask is provided with a polygonal opening and a transmittance gradient area positioned on at least one edge of the opening; the opening is positioned right above the opening; developing the exposed first color photoresist material layer to make the overlapped part become a form with an undercut structure after the development; and baking the developed first color photoresist material layer to collapse the overlapped part of the undercut structure, so as to reduce the final thickness of the overlapped part and form a first color filter layer. The manufacturing method improves the quality of the formed color filter layer.
Description
Technical Field
The invention relates to the field of liquid crystal display, in particular to a method for manufacturing a color filter layer.
Background
Liquid Crystal Displays (LCDs) typically have a color filter substrate therein. Taking a color filter substrate in a TFT (thin film transistor) -LCD as an example, the color filter substrate for a liquid crystal display at present mainly comprises a transparent glass substrate, a black matrix layer (BM layer), a color photoresist layer (RGB layer), and the like. The three primary colors of red (R), green (G) and blue (B) of the color filter substrate are arranged according to a certain pattern and correspond to sub-pixels (one pixel is composed of three sub-pixels) on an array substrate (usually used for manufacturing corresponding thin film transistors) one by one. White light emitted by a backlight source of the LCD forms lights with various colors after red, green and blue are mixed by penetrating through the color filter substrate, and rich color expression is obtained according to a corresponding color mixing principle.
In order to ensure color uniformity of the color filter substrate and prevent light leakage, there is generally a certain width of overlap between each color filter layer and the black matrix layer. In the manufacturing process of the traditional color filter substrate, in the overlapped (lapping) area of each color filter layer and the black matrix layer, the height of the laminated part is higher than that of other areas, so that a large angle step difference is generated, and the mobility of liquid crystal molecules which are subsequently contacted with the orientation layer is poor due to the angle step difference, so that the problems of press aberration and the like are generated, and the display effect is influenced.
Therefore, a new method for manufacturing a color filter layer is needed to improve the quality of the color filter layer.
Disclosure of Invention
The invention provides a method for manufacturing a color filter layer, which aims to improve the quality of the formed color filter layer.
In order to solve the above problems, the present invention provides a method for manufacturing a color filter layer, including: forming a black matrix layer on a transparent substrate, the black matrix layer having a plurality of openings; forming a first color photoresist layer of negative photoresist material in a first number of the openings, the first color photoresist layer filling the openings and having an overlapping portion covering the black matrix layer; exposing the first color photoresist material layer by using a first photomask as a mask; the first photomask is provided with a polygonal opening and a transmittance gradient area positioned on at least one edge of the opening; the opening is positioned right above the opening; the transmittance of the transmittance gradient area is lower than that of the opening, but higher than that of other parts of the first photomask; developing the exposed first color photoresist material layer to make the overlapped part form an undercut structure after the development; and baking the first color photoresist material layer after the development so that the overlapped part of the undercut structure collapses, thereby reducing the final thickness of the overlapped part and forming a first color filter layer.
Optionally, the transmittance gradient area has a transmittance change rule from the side back to the side close to the opening as follows: gradually going from high to low and then from low to high.
Optionally, the transmittance of the transmittance gradient area is 15% to 50%.
Optionally, the transmittance of the transmittance gradient area is 20% to 22%.
Optionally, the width of the transmittance gradient region is 2 μm to 5 μm.
Optionally, the distance from the orthographic projection of the transmittance gradient area on the black matrix layer to the opening is 0.5 μm to 1.5 μm.
Optionally, after the undercut structure is collapsed, the maximum thickness of the overlapped portion ranges from 0 μm to 0.15 μm.
Optionally, after the undercut structure is collapsed, the overlapped portion has a gentle bottom angle of the bottom angle and a smooth top angle, the angle range of the gentle bottom angle is 30 ° to 45 °, and the angle range of the smooth top angle is 120 ° to 160 °.
Optionally, the openings and the openings are rectangles, the plurality of openings are arranged in a row-column lattice manner, the first color photoresist material layer covers the openings in the same column in a row manner, the transmittance gradient area is arranged at the edge of a group of opposite sides of the rectangles, and the opposite sides of the transmittance gradient area are parallel to the column.
Optionally, the opening and the hole are rectangular, the first color photoresist layer includes a plurality of isolated rectangular sub-layers, each rectangular sub-layer covers one opening, and the transmittance gradient regions are disposed at two sets of opposite side edges of the rectangle.
Optionally, the manufacturing method further includes: forming a second color photoresist layer of negative photoresist material in a second number of the openings, the second color photoresist layer filling the openings and having an overlapping portion covering the black matrix layer; exposing the second color photoresist material layer by using a second photomask as a mask; the second photomask is provided with a polygonal opening and a transmittance gradient area positioned on at least one edge of the opening; the opening is positioned right above the opening; the transmittance of the transmittance gradient area is lower than that of the opening, but higher than that of other parts of the second photomask; developing the exposed second color photoresist material layer to make the overlapped part form an undercut structure after the development; and baking the developed second color photoresist material layer to collapse the overlapped part of the undercut structure, so as to reduce the final thickness of the overlapped part, thereby forming a second color filter layer.
Optionally, the manufacturing method further includes: forming a third color light resistance material layer of negative light resistance material in a third number of the openings, wherein the third color light resistance material layer fills the openings and has an overlapping part covering the black matrix layer; exposing the third color photoresist layer by using a third photomask as a mask; the third photomask is provided with a polygonal opening and a transmittance gradient area positioned on at least one edge of the opening; the opening is positioned right above the opening; the transmittance of the transmittance gradient area is lower than that of the opening, but higher than that of other parts of the third photomask; developing the exposed third color photoresist layer to make the overlapped part have undercut structure; baking the developed third color light resistance material layer to make the overlapped part of the undercut structure collapse, thereby reducing the final thickness of the overlapped part, and forming a third color light filtering layer.
Compared with the prior art, the technical scheme of the invention has the following advantages:
in the method provided by the technical scheme of the invention, the exposure intensity of the overlapped part of the first color photoresist material layer on the black matrix layer is adjusted by arranging the corresponding transmittance gradient area in the first photomask. On one hand, the first color photoresist layer in the opening is exposed completely through the opening of the first photomask; on the other hand, for the overlapped part of the first color photoresist material layer on the black matrix layer, the purpose of reducing the exposure intensity is realized through the specially designed transmittance gradient area of the first photomask. Therefore, the exposure intensity received by the first color photoresist material layer of the overlapped part is relatively reduced, the effect of reducing the thickness of the first color filter layer of the overlapped part is achieved, the quality of the formed first color filter layer is improved, and the reduction or avoidance of the angle section difference is realized, or the optimization of the angle section difference is realized. The manufacturing method can realize corresponding effects without improving corresponding exposure equipment or changing the exposure intensity of the equipment (the equipment still only needs to use uniform exposure intensity for exposure), thereby not only saving the cost, but also being convenient to directly carry out by using common process conditions and steps.
Drawings
Fig. 1 to 3 are schematic structural diagrams corresponding to each step of a conventional manufacturing method.
Fig. 4 to 8 are schematic structural diagrams corresponding to steps of a manufacturing method according to an embodiment of the present invention.
Detailed Description
Referring to fig. 1, if a conventional common mask is directly used to form a color filter layer, the corresponding steps can be as shown in fig. 1 to fig. 3.
A black matrix layer 110 is formed on the transparent substrate 100, the black matrix layer 110 having a plurality of openings, of which only one opening 111 is shown as a representative in fig. 1.
Thereafter, referring to fig. 1 and 2, a first color filter material layer 120 is formed in the opening 111 in fig. 1, and then the first color filter material layer 120 is exposed with a mask 130.
Thereafter, referring to fig. 2 and 3, the exposed first color filter material layer 120 is further subjected to steps of development and baking, etc., thereby becoming a first color filter layer 120 z. Thereafter, the same process as described above is repeated, thereby forming the second color filter layer 140z and the third color filter layer 150z in the other openings of the black matrix layer.
In the finally formed structure, since the overlapping portion of each color filter material layer and the black matrix layer has a larger thickness (as shown in fig. 2, the portion of the first color filter material layer 120 having the larger thickness overlaps the black matrix layer 110), the finally formed color filter layer and the black matrix layer have the angle step difference (ox horn, the thickness of the overlapping portion is too large) as mentioned in the background art, as shown in fig. 3.
Therefore, the invention provides a novel method for forming a color filter layer, which is characterized in that exposure intensity adjustment is carried out on the overlapped part of each color filter material layer and the black matrix layer to control the corresponding overlapped thickness, so that the situations of larger thickness overlap and angular section difference are avoided, the appearance of the formed color filter layer is optimized, the performance of the color filter layer is improved, the quality of the corresponding color filter substrate is improved, and the display quality of a liquid crystal display panel adopting the color filter substrate is improved.
In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below.
An embodiment of the invention provides a method for manufacturing a color filter layer, which includes steps 1 to 5, please refer to fig. 4 to 8.
Step 1, forming a black matrix layer on a transparent substrate, wherein the black matrix layer is provided with a plurality of openings.
Referring to fig. 4, the transparent substrate 200 may be a glass substrate. The black matrix layer 210 may be fabricated by a conventional fabrication method. The black matrix layer 210 functions to function as a light blocking property, a light absorbing property, and an impedance.
In fig. 4, one of the openings 211 is shown as a representative.
And 2, forming a first color photoresist material layer of negative photoresist material in the openings of the first quantity, wherein the openings are filled with the first color photoresist material layer, and the first color photoresist material layer is provided with an overlapped part covering the black matrix layer.
In fig. 5, the opening 211 of fig. 4 is covered by the first color photoresist layer 220 for illustration.
In this embodiment, the first color photoresist layer 220 may be formed by a coating method. Specifically, the coating method may further be a slit coating method.
The properties of the negative photoresist material are as follows: the portion irradiated by light is not removed by the subsequent development of the developing solution, and the remaining portion not irradiated by light is removed by the development of the developing solution. The material of the first color photoresist layer 220 is a negative photoresist material.
It should be noted that, as mentioned above, the black matrix layer has a plurality of openings, and in step 2, the first color photoresist layer is formed only in the first number of openings. In this case, the first number is related to the total number of the openings, and generally, the first number is determined according to the type of the color filter layer to be formed. For example, when three color filter layers need to be formed, the first number is one third of the total opening, and when four color filter layers are to be formed, the first number is one fourth of the total opening. That is, if N color filter layers are formed, the first number is one N times the total number of openings.
In this embodiment, the width of the overlapped portion of the first color photoresist layer 220 and the black matrix layer 210 can be controlled between 3 μm and 6 μm. If the width of the overlapped portion is controlled to be less than 3 μm, light leakage and the like may be caused once the corresponding processes are not well aligned. If the width of the overlapped portion is greater than 6 μm, the corresponding first color photoresist layer 220 may cover the black matrix layer 210 in a large amount, so that after the corresponding first color filter layer 220y is formed on the subsequent first color photoresist layer 220 (refer to the subsequent content of this specification), when the next color photoresist layer is formed subsequently, there are more overlapped portions between the next color photoresist layer and the first color filter layer 220y, and finally, the overlapping between the next color filter layer and the first color filter layer 220y is severe (for example, as shown in fig. 3), which is not favorable for improving the properties of the entire color filter substrate.
And step 3, exposing the first color photoresist material layer by using the first photomask as a mask. The first photomask is provided with a polygonal opening and a transmittance gradient area positioned on at least one edge of the opening. The opening is positioned right above the opening. The transmittance of the transmittance gradient region is lower than that of the opening, but higher than that of the other part of the first mask.
Step 3 may also be continued with reference to fig. 5, in which a first mask 230 is disposed over the transparent substrate 200, the black matrix layer 210 and the first color photoresist layer 220, and openings (not labeled) are located between the transmittance gradient regions 231.
In this embodiment, since the first color photoresist layer 220 is located in the opening 211, when the opening is located right above the opening, the opening is also located right above the first color photoresist layer 220 in the opening. However, the opening is wider than the opening, and thus, a small portion of the opening is located right above the first color photoresist layer 220 in the overlapped portion.
In this embodiment, the distance from the orthographic projection of the transmittance gradient region 231 on the black matrix layer 210 to the opening 211 is set to be 0.5 μm to 1.5 μm (at this time, the opening 211 is already filled with the first color photoresist layer 220). That is, the range of the opening is usually slightly larger than the range of the opening. This helps to make the first color photoresist layer 220 overlapping the edge of the black matrix layer 210 receive exposure as much as possible without blocking, so that this portion of the first color photoresist layer 220 becomes a part of the first color filter layer 220y (refer to the following description), ensuring better contact between the first color filter layer 220y and the black matrix layer 210, and ensuring that the black matrix layer 210 plays a corresponding role.
In this embodiment, the transmittance of the transmittance gradient area 231 is lower than that of the openings, and the transmittance of the openings is usually 100%, but the transmittance of the transmittance gradient area 231 is higher than that of the other parts of the first mask 230, and the other parts of the first mask 230 are usually also called non-opening parts, and the transmittance of the parts is usually close to 0.
In this embodiment, the transmittance gradient region 231 may have a width of 2 μm to 5 μm. The width of the transmittance gradient region 231 is related to the width of the overlapping portion (i.e., the overlapping portion of the first color photoresist layer 220 and the black matrix layer 210), and is related to the distance from the orthographic projection of the transmittance gradient region 231 on the black matrix layer 210 to the opening 211. As mentioned above, the width of the overlapping portion can be controlled to be 3 μm to 6 μm, and at this time, the distance (0.5 μm to 1.5 μm) from the orthographic projection of the front transmittance gradient area 231 on the black matrix layer 210 to the opening 211 is considered, so that the width of the transmittance gradient area 231 is set to be 2 μm to 5 μm, and thus, the transmittance gradient area 231 can well shield the portion of the first color photoresist layer 220 that needs to be subjected to exposure intensity adjustment during the exposure process, thereby realizing the partial shielding effect of the transmittance gradient area 231 on the exposure light, and further realizing the adjustment of the exposure intensity of the corresponding area.
In combination with the above, the transmittance gradient region 231 has a function different from that of the opening (not blocking light at all) and different from that of the non-opening portion (substantially not transmitting light) of the first mask 230, but partially blocks light therebetween.
In this embodiment, the transmittance of the transmittance gradient region may be further set to be 15% to 50%, so as to adjust the exposure intensity of the first color photoresist layer 220 at the overlapping portion.
In a more preferable range, the transmittance of the transmittance gradient region 231 may be 20% to 22%. Focusing on this range, the exposure intensity of the first color resist layer 220 at the overlapped portion can be precisely adjusted within a specific range, thereby ensuring the performance of the subsequent steps.
In a preferred arrangement, the transmittance gradient region 231 is arranged in the present embodiment such that the transmittance change rule from the side facing away from the opening to the side near the opening is as follows: gradually going from high to low and then from low to high.
The variation of transmittance of each portion of the first mask 230 is shown by the dashed lines in fig. 5. The transmittance of the transmittance gradient area 231 is "high at both ends and low in the middle", which is the expression that the transmittance change rule is "gradually decreases from high to low and then gradually decreases from low to high". Specific values of these transmittances can be selected from the ranges of 15% to 50% and 20% to 22%.
In this embodiment, the openings and the openings are rectangular, the openings are arranged in a matrix (not shown), and the first color photoresist layer 220 covers the openings in a row. Accordingly, the transmittance gradient region 231 is disposed at a set of opposite edges (corresponding to the at least one edge) of the rectangle, and the opposite edges of the transmittance gradient region are disposed in parallel to the rows. In this arrangement, the first color photoresist layer 220 does not need to be considered overlapping in the column direction. Because, the first color photoresist layer 220 covers the corresponding openings and the corresponding black matrix layer in an aligned manner. However, in the row direction, the first color photoresist layer 220 needs to prevent the first color filter layer 220y (refer to the content later in the specification) formed subsequently from overlapping with other color filter layers formed further subsequently, which causes the aforementioned angle step difference, and therefore, the corresponding transmittance gradient area 231 needs to be disposed in the row direction, and therefore, the opposite side where the transmittance gradient area 231 is disposed is parallel to the column (or, in this case, the specific connection line between two transmittance gradient areas 231 corresponding to one opening is perpendicular to the "column" and parallel to the "row"). At this time, two transmittance gradient areas 231 are corresponding to one opening of the first mask 230, and fig. 5 shows the two transmittance gradient areas 231 at the same time, so that fig. 5 is a cross-sectional structure cut parallel to the "row" direction.
It should be noted that, in other embodiments of the present invention, another setting may also be adopted: the openings and the holes are rectangular, the first color photoresist layer comprises a plurality of isolated rectangular sub-layers, each rectangular sub-layer covers one opening, and the transmittance gradient regions are arranged at two groups of opposite edges (corresponding to at least one edge) of the rectangle. The reason for this is that, with reference to the former arrangement, the overlapped portions of different color filter layers need to be considered in both directions, and therefore, transmittance gradient areas need to be respectively arranged in both directions (two pairs of edges, and four edges in total) (therefore, at this time, one opening on the photomask corresponds to four transmittance gradient areas).
In this embodiment, the exposure intensity of the overlapped portion of the first color photoresist layer 220 is corrected (or the exposure intensity received by the overlapped portion of the first color photoresist layer 220 is adjusted) by providing the corresponding transmittance gradient region 231, so as to reduce the thickness of the overlapped portion of the first color filter layer 220y after the subsequent development. Specifically, due to the arrangement of the transmittance gradient region 231, the exposure intensity received by the first color photoresist layer corresponding to the overlapped portion directly below the transmittance gradient region 231 is relatively reduced compared to the exposure intensity directly below the opening. Therefore, at least a portion of the overlapped portion of the first color photoresist layer 220 has relatively low cross-linking strength. Therefore, in fig. 5, the region 221 in which the crosslinking strength is large is shown, and the region 222 in which the crosslinking strength is small is shown. That is, the first color photoresist layer includes the region 221 and the region 222.
And 4, developing the exposed first color photoresist material layer, so that the overlapped part becomes a shape with an undercut structure after the development.
After the exposure is completed and the subsequent development is performed, since the cross-linking strength of the area 221 is low, the ratio of the first color photoresist layer 220 at the overlapped portion of the area to be developed and removed is increased, and therefore, the ratio of the first color photoresist layer 220 at the overlapped portion remaining on the corresponding black matrix layer 210 is decreased (the remaining portion is basically the portion of the area 222), so that the first color filter layer 220y finally located on the black matrix layer 210 has a relatively thin thickness, and further, the phenomenon that a large number of different color filter layers are overlapped with each other to generate a corner step (ox horn) is prevented.
In this embodiment, the undercut structure refers to: the post-development overlap portion of the first color photoresist layer 220x has a base angle greater than 90 degrees on the black matrix layer 210. This structure is equivalent to a configuration in which the overlapped portion of the bottom is cut inward to have a top width larger than that of the bottom, and thus, is called an undercut structure. It is the undercut structure that is susceptible to collapse during subsequent processing.
As mentioned above, this step utilizes the area 221 with low cross-linking strength, and the corresponding overlapped portion of the first color photoresist layer 220 is easily removed by development, so that the first color photoresist layer 220x after development has the form of undercut structure, as shown in fig. 6.
And 5, baking the developed first color photoresist material layer to collapse the overlapped part of the undercut structure, so as to reduce the final thickness of the overlapped part and form a first color filter layer.
In step 5, since the baking is performed on the overlapped portion of the undercut structure formed previously, the undercut structure naturally collapses under the gravity and the heating of the baking, and the final thickness of the overlapped portion is naturally reduced much after collapsing.
Specifically, the maximum thickness of the overlapped portion after the first color photoresist layer 220x of the undercut structure is collapsed is only 0 μm to 0.15 μm. In the conventional method, the maximum thickness of the corresponding overlapped part is usually in the range of 0.3 μm to 0.55 μm, and it can be seen that the maximum thickness of the overlapped part is reduced by this embodiment.
More importantly, since the undercut structure collapses under the action of gravity and the heating during baking, the final overlapped portion of the first color filter layer 220y will then have a very smooth shape, as shown in fig. 7. In such a gentle form, the overlapped portion (the overlapped portion at this time after the undercut structure is collapsed) has a gentle bottom angle as indicated by the enclosure of the broken-line box i in fig. 7, and the overlapped portion has a smooth top angle as indicated by the enclosure of the broken-line box j in fig. 7.
The angle range of the gentle bottom angle obtained by the steps of the method is 30-45 degrees, and the angle range of the smooth top angle is 120-160 degrees. In the existing method, the angle range of the bottom angle of the formed overlapping portion is usually 45 to 80 degrees (refer to fig. 2), and the angle range of the top angle is usually 60 to 100 degrees (refer to fig. 2).
Because the embodiment adjusts the corresponding gentle bottom angle range and smooth top angle range and adjusts the maximum thickness range of the overlapped part in front, the embodiment can realize that corresponding angle section difference does not appear subsequently, and corresponding layers are flattened, thereby improving the quality of the corresponding color filter substrate manufactured by adopting the method.
In the method provided in this embodiment, the adjustment (correction) of the exposure intensity (energy) of the overlapped portion is realized by providing the corresponding transmittance gradient region 231 in the first mask 230. On one hand, the first color photoresist layer 220 in the opening is exposed completely through the opening of the first mask 230; on the other hand, for the overlapped portion of the first color photoresist layer 220 on the black matrix layer 210, the purpose of reducing the exposure intensity is achieved by the specially designed transmittance gradient region 231 of the first mask 230. Therefore, the exposure intensity received by the first color photoresist layer 220 at the overlapping part is relatively reduced, the effect of reducing the thickness of the first color filter layer 220y at the overlapping part is achieved, the quality of the formed first color filter layer 220y is improved, and the reduction or avoidance of the angle step difference is realized, or the optimization of the angle step difference is realized. The manufacturing method can realize corresponding effects without improving corresponding exposure equipment or changing the exposure intensity of the equipment (the equipment still only needs to use uniform exposure intensity for exposure), thereby not only saving the cost, but also being convenient to directly carry out by using common process conditions and steps.
In this embodiment, the above steps are only completed to manufacture the first color filter layer 220y corresponding to a part of the openings, and in the subsequent steps of this embodiment, the following steps may be further performed:
forming a second color photoresist layer of negative photoresist material in the second number of openings, wherein the second color photoresist layer fills the openings and has an overlapped part covering the black matrix layer; exposing the second color photoresist material layer by using a second photomask as a mask; the second photomask is provided with a polygonal opening and a transmittance gradient area positioned on at least one edge of the opening; the opening is positioned right above the opening; the transmittance of the transmittance gradient area is lower than that of the opening, but higher than that of other parts of the second photomask; developing the exposed second color photoresist material layer to make the overlapped part become a form with an undercut structure after the development; baking the developed second color photoresist layer to collapse the overlapped portion of the undercut structure, thereby reducing the final thickness of the overlapped portion to form the second color filter layer 240 y.
After the formation of the second color filter layer, the following steps may be further performed:
forming a third color light resistance material layer of negative light resistance material in the third number of openings, wherein the third color light resistance material layer fills the openings and is provided with an overlapped part covering the black matrix layer; exposing the third color photoresist layer by using a third photomask as a mask; the third light cover is provided with a polygonal opening and a transmittance gradient area positioned on at least one edge of the opening; the opening is positioned right above the opening; the transmittance of the transmittance gradient area is lower than that of the opening, but higher than that of other parts of the third photomask; developing the exposed third color photoresist layer to make the overlapped part form an undercut structure; baking the developed third color light-resistant material layer to collapse the overlapped part of the undercut structure, thereby reducing the final thickness of the overlapped part to form the third color light-filtering layer 250 y.
The above-described process of forming the second color filter layer 240y and the third color filter layer 250y is a process of repeating the process of forming the first color filter layer 220y, and therefore, their specific processes may refer to the aforementioned counterparts of the present specification. Accordingly, the second number and the third number are generally equal to the first number.
After the above steps, the present embodiment forms the structure shown in fig. 8, specifically, the structure has the black matrix layer 210 located on the transparent substrate 200, and the first color filter layer 220y, the second color filter layer 240y, and the third color filter layer 250y located in each opening (the opening refers to the foregoing) of the black matrix layer 210. It can be seen that, in the color filter layers developed by the method of this embodiment, the overlapping portions between the color filter layers are small, and the thickness is low, so that the surface flatness of each color filter layer is improved (see fig. 3 for comparison).
It should be noted that, after the fabrication of the above structure is completed, the fabrication of structures such as a protection layer (OC), a transparent conductive layer (the material of the transparent conductive layer may be an ITO layer, and may be fabricated on the front side or the back side of the transparent substrate), and a Spacer (PS) may be performed subsequently in this embodiment, so as to further complete the color filter substrate with more comprehensive structural functions. The transparent conductive layer may be omitted.
Although the present invention is disclosed above, the present invention is not limited thereto. Various changes and modifications may be effected therein by one skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.
Claims (11)
1. A method for manufacturing a color filter layer is characterized by comprising the following steps:
forming a black matrix layer on a transparent substrate, the black matrix layer having a plurality of openings;
forming a first color photoresist layer of negative photoresist material in a first number of the openings, the first color photoresist layer filling the openings and having an overlapping portion covering the black matrix layer;
exposing the first color photoresist material layer by using a first photomask as a mask; the first photomask is provided with a polygonal opening and a transmittance gradient area positioned on at least one edge of the opening; the opening is positioned right above the opening;
developing the exposed first color photoresist material layer to make the overlapped part form an undercut structure after the development;
baking the first color photoresist material layer after the development is carried out, so that the overlapped part of the undercut structure is collapsed, the final thickness of the overlapped part is reduced, and a first color filter layer is formed;
the change rule of the transmittance gradient area from the side back to the side close to the opening is as follows: gradually going from high to low and then from low to high.
2. The method according to claim 1, wherein the transmittance of the transmittance gradient region is 15% to 50%.
3. The method according to claim 1, wherein the transmittance of the transmittance gradient region is 20% to 22%.
4. The method according to claim 1, wherein the transmittance gradient region has a width of 2 μm to 5 μm.
5. The manufacturing method of claim 1, wherein a distance from an orthographic projection of the transmittance gradient region on the black matrix layer to the opening is 0.5 μm to 1.5 μm.
6. The method of claim 1, wherein after the undercut structure is collapsed, the maximum thickness of the overlapped portion is in a range of 0 μm to 0.15 μm.
7. The method of claim 1, wherein after the undercut structure is collapsed, the overlapped portion has a gentle bottom angle of the bottom angle and a smooth top angle, the gentle bottom angle has an angle range of 30 ° to 45 °, and the smooth top angle has an angle range of 120 ° to 160 °.
8. The method according to claim 1, wherein the openings and the openings are rectangular, the plurality of openings are arranged in a matrix of rows and columns, the first color photoresist layer covers the openings in the same column in rows, the transmittance gradient area is disposed at edges of a set of opposite sides of the rectangular, and the opposite sides of the transmittance gradient area are disposed parallel to the columns.
9. The method of claim 1, wherein the openings and the openings are rectangular, the first color photoresist layer comprises a plurality of isolated rectangular sub-layers, each rectangular sub-layer covers one of the openings, and the transmittance gradient regions are disposed at two opposite edges of the rectangle.
10. The method of manufacturing according to claim 1, further comprising:
forming a second color photoresist layer of negative photoresist material in a second number of the openings, the second color photoresist layer filling the openings and having an overlapping portion covering the black matrix layer;
exposing the second color photoresist material layer by using a second photomask as a mask; the second photomask is provided with a polygonal opening and a transmittance gradient area positioned on at least one edge of the opening; the opening is positioned right above the opening; the transmittance of the transmittance gradient area is lower than that of the opening, but higher than that of other parts of the second photomask;
developing the exposed second color photoresist material layer to make the overlapped part form an undercut structure after the development;
and baking the developed second color photoresist material layer to collapse the overlapped part of the undercut structure, so as to reduce the final thickness of the overlapped part, thereby forming a second color filter layer.
11. The method of manufacturing according to claim 10, further comprising:
forming a third color light resistance material layer of negative light resistance material in a third number of the openings, wherein the third color light resistance material layer fills the openings and has an overlapping part covering the black matrix layer;
exposing the third color photoresist layer by using a third photomask as a mask; the third photomask is provided with a polygonal opening and a transmittance gradient area positioned on at least one edge of the opening; the opening is positioned right above the opening; the transmittance of the transmittance gradient area is lower than that of the opening, but higher than that of other parts of the third photomask;
developing the exposed third color photoresist layer to make the overlapped part have undercut structure;
baking the developed third color light resistance material layer to make the overlapped part of the undercut structure collapse, thereby reducing the final thickness of the overlapped part, and forming a third color light filtering layer.
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| JP3983841B2 (en) * | 1997-01-20 | 2007-09-26 | 大日本印刷株式会社 | Manufacturing method of color filter |
| CN1576990A (en) * | 2003-07-29 | 2005-02-09 | 友达光电股份有限公司 | Method for producing colour Light filter membrane substrate and its structure |
| CN1731285A (en) * | 2004-08-07 | 2006-02-08 | 鸿富锦精密工业（深圳）有限公司 | Manufacturing method of color filters and exposure device |
| KR20070006485A (en) * | 2005-07-08 | 2007-01-11 | 삼성전자주식회사 | Method of manufacturing liquid crystal display and liquid crystal display manufactured thereby |
| CN102236258B (en) * | 2010-04-26 | 2012-11-28 | 奇美实业股份有限公司 | Photosensitive resin composition and colour filter formed by same and liquid crystal display assembly containing colour filter |
| CN102331595B (en) * | 2011-06-17 | 2013-09-04 | 深圳市华星光电技术有限公司 | Liquid crystal display panel, colour filter and manufacturing method of colour filter |
| CN102854656A (en) * | 2012-09-29 | 2013-01-02 | 深圳市华星光电技术有限公司 | Colored light filtering substrate and relative manufacturing method thereof |
| CN104749674A (en) * | 2013-12-30 | 2015-07-01 | 上海仪电显示材料有限公司 | Light filter manufacturing method and exposure mask plate |
| CN104503128B (en) * | 2014-12-19 | 2018-01-09 | 深圳市华星光电技术有限公司 | Manufacture method for the color membrane substrates of display |
| CN105388661B (en) * | 2015-12-21 | 2019-01-04 | 京东方科技集团股份有限公司 | Color membrane substrates and preparation method thereof, display device |
| CN105974728A (en) * | 2016-06-29 | 2016-09-28 | 武汉华星光电技术有限公司 | Photomask and manufacturing method of color film substrate |
| CN106054443A (en) * | 2016-08-18 | 2016-10-26 | 京东方科技集团股份有限公司 | Color-film substrate, production method thereof, display panel and production method thereof |
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