WO2020118937A1

WO2020118937A1 - Preparation method for black matrix and display device

Info

Publication number: WO2020118937A1
Application number: PCT/CN2019/078210
Authority: WO
Inventors: 陈黎暄
Original assignee: 深圳市华星光电半导体显示技术有限公司
Priority date: 2018-12-15
Filing date: 2019-03-15
Publication date: 2020-06-18
Also published as: CN109471294A

Abstract

A preparation method for a black matrix and a display device (20), comprising: providing a substrate (21) (S1); coating the upper surface of the substrate (21) with a layer of refractive index temperature control materials (S2); pre-baking the refractive index temperature control materials to form an intermediate layer (22) (S3); coating the intermediate layer (22) with a photoresist material to form a photoresist layer (23) (S4); placing a mask (24) above the photoresist layer (23) or below the substrate (21) (S5); irradiating the photoresist layer (23) by using ultraviolet rays from top to bottom or irradiating the substrate (21) from bottom to top to achieve simultaneous curing and developing of the intermediate layer (22) and the photoresist layer (23) (S6); removing the mask (24) and baking the substrate (21) to achieve simultaneous patterning of the intermediate layer (22) and the photoresist layer (23) (S7). In this way, the preparation efficiency can be improved.

Description

Black matrix preparation method and display device

Technical field

The invention relates to the field of liquid crystal display, in particular to a method for preparing a black matrix and a display device.

Background technique

The LCD display can reduce the reflection of ambient light on the surface of the display by reducing the reflection rate, so that the actual contrast perceived by the human eye in a bright environment increases, and the image quality effect is enhanced. In addition to the reflection of the polarizer on the upper surface of the existing LCD, the black matrix prepared on the inner side of the glass of the upper substrate also generates light reflection. By improving the reflection of the black matrix, it is helpful to reduce the overall reflectivity of the LCD and improve the contrast.

The existing patent proposes a method of adding an organic or inorganic refractive index intermediate layer between the ordinary black matrix and the glass substrate to reduce the reflectivity of the black matrix. However, there are the following problems in the production process: if a full-faced intermediate layer is used, it may have an impact on the reflectance and transmittance of the area outside the black matrix on the color filter substrate, and the intermediate layer material may cause absorption of transmitted light; if the intermediate layer The material uses inorganic materials such as silicon oxynitride, etc., to make it patterned to be consistent with the black matrix, then a dry etching process needs to be added, which increases the complexity of preparation.

technical problem

The object of the present invention is to provide a method for preparing a black matrix, which can remove the steps of the dry etching process of the intermediate layer.

Technical solution

In order to solve the above technical problems, the present invention provides a method for preparing a black matrix, comprising the following steps: providing a substrate; coating a layer of refractive index temperature control material on the surface of the substrate; Pre-bake to form an intermediate layer; coat a photoresist material on the intermediate layer to form a photoresist layer; place a mask plate above the photoresist layer or below the substrate; use ultraviolet light The photoresist layer is irradiated from top to bottom, or the substrate is irradiated from bottom to top, so that the intermediate layer and the photoresist layer are simultaneously cured and developed; the mask plate is removed and the substrate is baked so that The intermediate layer is patterned synchronously with the photoresist layer.

Further, in the step of providing a substrate, the substrate is provided with a first alignment mark; in the step of placing a mask plate above the photoresist layer or below the substrate, the mask plate A second alignment mark is provided, and the second alignment mark is in one-to-one correspondence with the first alignment mark, respectively.

Further, the first alignment marks are provided at four corners of the substrate, and the second alignment marks are provided at four corners of the mask plate.

Further, in the step of coating a layer of refractive index temperature control material on the upper surface of the substrate, the refractive index of the intermediate layer is 1.45 to 1.9, and the coating thickness of the intermediate layer is 35 to 85 nm.

Further, the substrate is a color filter substrate or a glass substrate; the refractive index temperature control material is a siloxane-based polymer.

Further, the photoresist material includes a negative photoresist and a metal halide, and the photoresist layer is a black matrix layer made of black photoresist.

Further, in the step of pre-baking the refractive index temperature control material, the baking temperature is 70~110°C; in the step of removing the mask plate and baking the substrate, the baking temperature It is 230~300°C.

Further, the intermediate layer and the photoresist layer are both positive photoresists, or the intermediate layer and the photoresist layer are both negative photoresists.

Another object of the present invention is to provide a display device including a substrate, an intermediate layer and a photoresist layer, a substrate, a photoresist layer and an intermediate layer, the intermediate layer being disposed between the substrate and the photoresist layer The intermediate layer and the photoresist layer are simultaneously cured and developed on one side of the substrate, and the pattern of the intermediate layer corresponds to the pattern of the photoresist layer.

Further, a first alignment mark is provided on the substrate, and a second alignment mark is provided on the mask plate, and the second alignment mark corresponds to the first alignment mark respectively.

Beneficial effect

The invention provides a method for preparing a black matrix, and the UV layer is used to pattern the intermediate layer together with the black matrix, thereby reducing the dry etching process of the intermediate layer and improving the manufacturing efficiency.

BRIEF DESCRIPTION

In order to more clearly explain the technical solutions in the embodiments of the present invention, the drawings required in the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For those skilled in the art, without paying any creative work, other drawings can be obtained based on these drawings.

1 is a flowchart of a method for preparing a black matrix in the present invention;

2 is a schematic structural diagram of a substrate according to an embodiment of the present invention;

3 is a schematic structural diagram of a substrate and an intermediate layer according to an embodiment of the present invention;

4 is a schematic structural view of a substrate, an intermediate layer, and a photoresist layer according to an embodiment of the present invention;

5 is a schematic view of the structure of the mask plate illumination according to an embodiment of the present invention;

6 is a schematic diagram of the first alignment mark of the substrate of FIG. 2;

7 is a schematic diagram of the second alignment mark on the mask plate of FIG. 5;

8 is a schematic diagram of the structure of the black matrix prepared by the present invention;

9 is a schematic view of the structure of the present invention provides ultraviolet exposure from bottom to top;

10 is a display device provided by the present invention.

Embodiments of the invention

The following is a description of each embodiment with reference to the attached drawings to illustrate specific embodiments of the invention that can be implemented. Directional terms mentioned in the present invention, such as up, down, front, back, left, right, inside, outside, side, etc., are only directions referring to the drawings. The names of elements mentioned in the present invention, such as first and second, are only to distinguish different meta-components, which can be better expressed. In the figure, units with similar structures are denoted by the same reference numerals.

Herein, embodiments of the present invention will be described in detail with reference to the drawings. The present invention can be embodied in many different forms, and the present invention should not be interpreted merely as the specific embodiments set forth herein. The embodiments of the present invention are provided to explain the actual application of the present invention, so that those skilled in the art can understand various embodiments of the present invention and various modifications suitable for specific intended applications.

As shown in FIG. 1, the present invention provides a method for preparing a black matrix, including the following steps S1 to S7.

S1. As shown in FIG. 2, a substrate 21 is first provided, and a first alignment mark 211 is provided on the substrate 21. As the substrate 21, a color film substrate or a common glass substrate can be used. In the present invention, the added intermediate layer and the black matrix are patterned at once, which is used to divide adjacent color groups, block the color gaps, prevent light leakage or color mixing; and the intermediate layer can reduce the reflectivity of the black matrix, Thereby reducing the reflectivity of the panel and the reflectivity of the entire LCD, it can also share the difficulty and cost of polarizer surface treatment. As shown in FIG. 6, the substrate 21 is rectangular, and the first alignment marks 211 are provided at the four corners of the substrate 21. Since the glass substrate is used, it is not necessary to refer to the alignment marks of the previous preparation process in the preparation process of the present invention. . The shape of the first alignment mark 211 may be rectangular or circular, and the present invention is preferably a circular mark. The first alignment mark 211 can provide a position reference for coating and mask plate placement in other layers of the present invention.

S2. As shown in FIG. 3, a layer of refractive index temperature control material is coated on the upper surface of the substrate 21. The refractive index temperature control material is a siloxane-based material. The material is generally a pure metal salt monomer such as Si(OR)4 or Ti(OR)4. The refractive index characteristic of the material changes with temperature. The refractive index of the layer is 1.45~1.9, and its coating thickness is 35~85nm. Preferably, the refractive index may be 1.45, 1.50, 1.6, 1.7, or 1.90, and the thickness of the coating intermediate layer 22 may be 35 nm, 45 nm, 55 nm, 75 nm, or 85 nm.

S3. The third step is to pre-bake the refractive index temperature control material to form an intermediate layer 22. In the coating step of the intermediate layer 22, the material to be coated is a transparent gel, so the material is pre-baked to stabilize it and form the intermediate layer 22, so as to facilitate the subsequent steps. In step S3, the pre-baking temperature may be 70°C, 80°C, 90°C or 110°C.

S4. As shown in FIG. 4, a photoresist material is coated on the intermediate layer 22 to form a photoresist layer 23. The photoresist material is mainly negative photoresist and metal halide. The photoresist layer 23 is a black matrix made of black photoresist. The photoresist layer 23 may also be called a black matrix layer. In the unexposed state, the photoresist layer 23 assumes a transparent state. The thickness of the coated photoresist layer 23 is 0.8um, 1.0um, 1.4um or 1.5um. Preferably, the metal halide is silver bromide or silver chloride, which will turn black during exposure to form a black matrix. The negative photoresist is the main component of the photoresist system. It is a soluble substance when it is not exposed, and it is soluble in the developer. It solidifies after exposure and becomes an insoluble substance; and the metal halide is silver bromide, which decomposes to form metal particles after exposure. The metal particles will appear as small particles Black, with high optical density value.

S5. As shown in FIG. 5, a mask plate 24 is placed above the photoresist layer 23 or below the substrate 21. As shown in FIG. 7, the mask plate is provided with a second alignment mark 241. The mask plate 24 has a plurality of mask plate through holes. The pattern formed by the plurality of mask plate through holes is consistent with the pattern of the photoresist layer 23. The second alignment marks 241 are provided at four corners of the mask plate. When the mask plate 24 is installed, the second alignment marks 241 correspond to the first alignment marks 211 one-to-one.

S6. Irradiate the photoresist layer 23 with ultraviolet light from top to bottom, or irradiate the substrate 21 from bottom to top so that the intermediate layer and the photoresist layer are cured and developed simultaneously. Wherein, the position on the photoresist layer 23 corresponding to the through hole of the mask plate 24 is the illumination area, and the metal halide in the photoresist layer 23 in the illumination area decomposes to form metal particles, so that the photoresist layer 23 in the illumination area appears black, thus The black matrix light shielding function is realized, and at the same time, the photoresist layer 23 in the illuminated area becomes insoluble in the developing solution, thereby remaining in the subsequent developing step. The photoresist characteristics of the intermediate layer 22 are the same as the photoresist characteristics of the photoresist layer 23, which can be eliminated by a developer after being exposed to ultraviolet rays. As a result, the intermediate layer 22 and the photoresist layer 23 in the illuminated area are insoluble in the developer at the same time, and the unexposed area can be removed with the developer, so that the intermediate layer 22 and the photoresist layer 23 form the same pattern, and the two simultaneously cure development. After the mask plate is irradiated with ultraviolet rays, the exposed area can be eliminated with the developer, resulting in that the photoresist layer 23 and the intermediate layer 22 can be eliminated by the developer at the same time, which can reduce the previous step of photolithography of the intermediate layer separately. At the same time curing and development. As shown in FIG. 9, for the irradiation direction of the ultraviolet light, it can be selected to irradiate from above the photoresist layer 23, or it can be irradiated from below the substrate 21, which does not affect the results of the present invention. Illuminate above 23.

S7. The mask plate 24 is removed and the substrate is baked, so that the intermediate layer 22 and the photoresist layer 23 are patterned synchronously. The mask plate 24 is selected as a positive photoresist material, which can be eliminated with a developing solution after being exposed to light. Finally, the black matrix structure shown in FIG. 8 can be obtained.

Because in the above step S3, the baking temperature is only to preliminarily shape the intermediate layer 22, and the refractive index of the intermediate layer 22 is not optimized, it needs to be baked twice to make the refractive index of the intermediate layer 22 further Optimization, while making the intermediate layer 22 and the photoresist layer 23 form the same pattern, so that the two are simultaneously patterned.

In the present invention, the temperature range of the secondary baking is 230 to 300°C, preferably 230°C, 250°C, 270°C, 300°C. After baking, the intermediate layer 22 and the photoresist The layer 23 is stably fixed to the substrate, forming the structure shown in FIG. 5. The secondary baking can make the refractive index of the intermediate layer 22 reach the range of 1.45 to 1.9, which can further reduce the reflection of the black matrix, reduce the reflection characteristics of the overall LCD, and can also share the difficulty and cost of polarizer surface treatment.

Specifically, the intermediate layer takes a siloxane-based material as an example, the material is mainly a pure metal salt monomer such as Si(OR)4 or Ti(OR)4, and the pure metal salt monomer is first polymerized The reaction produces an inorganic polymer or an organic-inorganic hybrid polymer siloxane system. The molecular structure of the polymer is: then the polymer is applied to the substrate to form a glue layer, which is finally stabilized by ultraviolet baking The molecular structure of the material and the refractive index of the material can be controlled within 1.45~1.9. The molecular structure formula of the intermediate layer finally formed is as follows.

In the embodiment provided by the present invention, since the baking temperature is relatively high, the substrate 21 should have high temperature resistance characteristics, and it should not affect its normal operation. The photoresist characteristics of the intermediate layer 22 and the photoresist layer 23 should be the same. Negative photoresist is used in the present invention. This feature cannot be eliminated by the developer after exposure. In other embodiments, positive photoresist can be used, which does not affect the results of the present invention.

As shown in FIG. 10, the present invention provides a display device 20, which includes a substrate 21, an intermediate layer 22, an optical group layer 23, a colored layer 29, an ITO layer 25, a liquid crystal layer 26, and a thin film transistor Array 27 and a cover 28. The intermediate layer 22 is provided on the side of the substrate 21, and the photoresist layer 23 is provided on the side of the intermediate layer 22 away from the substrate 21; the intermediate layer 22 and the photoresist layer 23 are simultaneously cured and developed, and synchronized Patterned. The material of the intermediate layer 22 is a refractive index temperature control material of a siloxane-based polymer; the material of the photoresist layer 23 includes a negative photoresist and a metal halide. The colored layer 29 is alternately provided on the substrate with the intermediate layer 22 and the photoresist layer 23. The ITO layer 25 is provided on the side of the colored layer 29 and the photoresist layer 23 away from the intermediate layer 22. The substrate 21 is arranged opposite to the cover plate 28 with a gap (not shown) between them to fill the liquid crystal layer 26. The thin film transistor array 27 is disposed on the side of the cover plate 28 adjacent to the liquid crystal layer 27. The ITO layer 25 cooperates with the thin film transistor array 27 to control whether the liquid crystal molecules of the liquid crystal layer 26 rotate with an electric field, thereby controlling the passing of light from the backlight system (not shown). The light passing through the liquid crystal layer 26 is incident on the colored layer 29 and the photoresist layer 23, and the colored layer 29 only passes through three colors of red, blue, and green. The photoresist layer 23 is used to block the pipeline between the colored layers 29 to prevent light leakage The characteristics of the intermediate layer 22 and the photoresist layer 23 are the same to further prevent light leakage.

During the preparation process of the display device 20, a first alignment mark 211 (marked in FIG. 6) is provided on the substrate 21, and the first alignment mark 211 is provided at four corners of the substrate 21. The mask plate 24 is provided with second alignment marks 241 (marked in FIG. 7 ), the second alignment marks 241 are provided at four corners of the mask plate 24 and are respectively aligned with the first The marks 211 correspond to each other. In the display device, the intermediate layer 22 and the photoresist layer 23 are simultaneously cured and developed, and patterned simultaneously, and finally the mask plate is removed. The display device reduces the dry etching process of the intermediate layer 22 and increases the efficiency of the process flow.

The technical scope of the present invention is not limited to the content in the description, and those skilled in the art can make various variations and modifications to the embodiments without departing from the technical idea of the present invention, and these variations and modifications are all It should fall within the scope of the present invention.

Claims

A method for preparing a black matrix is characterized in that it includes the following steps:

Provide a substrate;

Coating a layer of refractive index temperature control material on the upper surface of the substrate;

Pre-baking the refractive index temperature control material to form an intermediate layer;

Coating a photoresist material on the intermediate layer to form a photoresist layer;

Placing a mask plate above the photoresist layer or below the substrate;

Irradiating the photoresist layer with ultraviolet light from top to bottom, or irradiating the substrate from bottom to top, so that the intermediate layer and the photoresist layer are simultaneously cured and developed;

The mask plate is removed and the substrate is baked so that the intermediate layer is patterned simultaneously with the photoresist layer.
The method for preparing a black matrix according to claim 1, wherein:

In the step of providing a substrate,

A first alignment mark is provided on the substrate;

In the step of placing the mask plate above the photoresist layer or below the substrate,

The mask plate is provided with a second alignment mark,

The second alignment marks correspond to the first alignment marks, respectively.
The method for preparing a black matrix according to claim 2, wherein:

The first alignment marks are provided at four corners of the substrate,

The second alignment marks are provided at four corners of the mask plate.
The method for preparing a black matrix according to claim 1, wherein:

In the step of coating a layer of refractive index temperature control material on the upper surface of the substrate,

The refractive index of the intermediate layer is 1.45~1.9,

The coating thickness of the intermediate layer is 35-85 nm.
The method for preparing a black matrix according to claim 1, wherein:

The substrate is a color film substrate or a glass substrate;

The refractive index temperature control material is a siloxane polymer.
The method for preparing a black matrix according to claim 1, wherein:

The photoresist material includes negative photoresist and metal halide,

The photoresist layer is a black matrix layer made of black photoresist.
The method for preparing a black matrix according to claim 1, wherein:

In the step of pre-baking the refractive index temperature control material,

The baking temperature is 70~110°C;

In the step of removing the mask plate and baking the substrate,

The baking temperature is 230~300°C.
The method for preparing a black matrix according to claim 1, wherein:

The intermediate layer and the photoresist layer are both positive photoresists, or,

The intermediate layer and the photoresist layer are both negative photoresists.
A display device, characterized in that it includes

Substrate, photoresist layer, intermediate layer and mask plate,

The intermediate layer is provided between the substrate and the photoresist layer;

The intermediate layer and the photoresist layer are simultaneously cured and developed on one side of the substrate,

The pattern of the intermediate layer corresponds to the pattern of the photoresist layer.
The display device according to claim 9, wherein:

A first alignment mark is provided on the substrate, and a second alignment mark is provided on the mask plate, and the second alignment mark corresponds to the first alignment mark respectively.