Display panel, array substrate, photoresist and preparation method thereof

Abstract

The present invention provides a photolithography process for a liquid crystal display panel, a photoresist and a preparation method thereof. The photoresist is based on an acrylic polymer and a functional group ‑(CH2)n‑Ph‑(COOH)m is introduced into the main body, thereby reducing exposure time and improving production efficiency.

Description

Technical Field

[0001] The present invention relates to the field of electronic display technology, and in particular to a display panel, an array substrate, a photoresist and a preparation method thereof. Background Art

[0002] Thin Film Transistor-Liquid Crystal Display (TFT-LCD) has become the mainstream flat panel display device on the market due to its advantages such as large display size, energy saving and environmental protection, high definition, and light weight.

[0003] The photolithography process of TFT-LCD refers to coating photoresist on the substrate to be processed, and then transferring the fine pattern of the mask to the surface of the substrate through processes such as exposure and development, and then performing processes such as etching and stripping to obtain high-precision patterns on the surface of the substrate. However, in the current photolithography process, the exposure energy is too high, resulting in too long exposure time and low production efficiency, making the production capacity of a single device unable to meet the growing market demand.

[0004] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of the present disclosure. Summary of the invention

[0005] The object of the present invention is to provide a photoresist with high developing ability and a preparation method thereof, as well as an array substrate having the photoresist and a display panel having the array substrate.

[0006] Other features and advantages of the present invention will become apparent from the following detailed description, or may be learned in part by the practice of the present disclosure.

[0007] According to one aspect of the present invention, a photoresist is provided, wherein the structural formula of the photoresist is:

[0008]

[0009] Wherein, Ph represents a phenyl group, the value of m is 0 to 5, and -COOH can replace H at any position on the phenyl group, and the value of n is 1 to 6.

[0010] In some embodiments of the present invention, when m is 2 and n is 1, the structural formula of -CH2-Ph-(COOH)2 is:

[0011]

[0012] In some embodiments of the present invention, when m is 1 and n is 1, the structural formula of -CH2-Ph-COOH is:

[0013]

[0014] In some embodiments of the present invention, the photoresist is prepared by reacting an acrylic polymer with Br(CH2)n-Ph-(COOH)m.

[0015] In some embodiments of the present invention, the molar ratio of the acrylic polymer to the Br(CH2)n-Ph-(COOH)m is 1:(1.05-1.3).

[0016] In some embodiments of the present invention, the molar ratio of the acrylic polymer to the Br(CH2)n-Ph-(COOH)m is 1:1.1.

[0017] According to one aspect of the present invention, there is provided a method for preparing a photoresist, comprising the following steps:

[0018] Weighing an acrylic polymer and Br(CH2)n-Ph-(COOH)m according to a molar ratio of 1:(1.05-1.3) and mixing them uniformly to obtain a mixture; wherein Ph represents a phenyl group, m has a value of 0-5, and -COOH can replace H at any position on the phenyl group;

[0019] Weigh sodium hydroxide according to a molar ratio of sodium hydroxide: the mixture of 1: (15-20), and adjust the pH to 10-11 to obtain a reactant;

[0020] The above reactants are heated to reflux at 120°C to 180°C under N2 environment for 18 to 30 hours to obtain a crude product after the reaction is complete;

[0021] The crude product was recrystallized and filtered using ethyl acetate and petroleum ether in a volume ratio of 1:3 as solvent, and the liquid obtained by filtration was dried to obtain a photoresist.

[0022] In some embodiments of the present invention, the molar ratio of the acrylic polymer to the Br(CH2)n-Ph-(COOH)m is 1:1.1.

[0023] According to one aspect of the present invention, an array substrate is provided, comprising a substrate, a color resist layer disposed on the substrate, and the above-mentioned photoresist, wherein the photoresist is disposed above the color resist layer.

[0024] According to one aspect of the present invention, a display panel is provided, comprising the array substrate as described above and an opposite substrate arranged opposite to the array substrate.

[0025] It can be seen from the above technical solution that the present invention has at least the following advantages and positive effects:

[0026] The photoresist in the present invention is mainly composed of an acrylic polymer, and a functional group - (CH2)n-Ph-(COOH)m is introduced into the main body, which can accelerate the reaction rate with tetramethylammonium hydroxide, increase the development neutralization reaction, reduce the acid substance provided by the photoreaction, and reduce the required exposure energy, thereby reducing the exposure time and improving production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The drawings herein are incorporated into the specification and constitute a part of the specification, showing embodiments consistent with the present invention, and together with the specification, are used to explain the principles of the present disclosure. Obviously, the drawings described below are only some embodiments of the present disclosure, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. In the drawings:

[0028] Figure 1 The structural formula of the photoresist in the present invention is shown.

[0029] Figure 2 The photolithography process principle of PFA is shown.

[0030] Figure 3 The size information of the pattern formed by overlaying on RGB is shown.

[0031] Figure 4 A schematic diagram showing the film thickness after PFA exposure.

[0032] Figure 5 A flow chart showing the method for preparing the photoresist in the invention. DETAILED DESCRIPTION

[0033] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in a variety of forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided so that this disclosure will be more comprehensive and complete and will fully convey the concept of the example embodiments to those skilled in the art.

[0034] In addition, the described features, structures or characteristics may be combined in one or more embodiments in any suitable manner. In the following description, many specific details are provided to provide a full understanding of the embodiments of the present disclosure. However, those skilled in the art will appreciate that the technical solutions of the present disclosure may be practiced without one or more of the specific details, or other methods, components, devices, steps, etc. may be adopted. In other cases, known methods, devices, implementations or operations are not shown or described in detail to avoid blurring the various aspects of the present disclosure.

[0035] The flowcharts shown in the accompanying drawings are only exemplary and do not necessarily include all contents and operations / steps, nor must they be executed in the order described. For example, some operations / steps can be decomposed, and some operations / steps can be combined or partially combined, so the actual execution order may change according to actual conditions.

[0036] Photolithography is a common process in the liquid crystal display (LCD) industry, and photoresist is a necessary material for the photolithography process. When exposed to a light beam, photoresist can undergo cross-linking, curing, or degradation reactions. Since photoresist is not corroded by etching liquid after undergoing a photocross-linking and curing reaction, it is often used in the patterned etching process of display panels, and can also be retained in the panel as a material, such as the black matrix on the CF substrate side, the color green light layer RGB color resistance, the organic cover layer (OC) and the spacer (PS), etc., and the organic insulating flat layer (Polymer Film on Array, PFA) on the TFT array substrate side.

[0037] Among them, the PFA lithography process usually includes:

[0038] Gluing: Coating photoresist on the substrate so that the photoresist covers RGB.

[0039] Specifically, the substrate is glass, RGB is arranged on the glass, and the photoresist covers the RGB and the substrate.

[0040] Soft baking: soft baking the above-mentioned substrate, RGB and photoresist.

[0041] Exposure, selectively exposing the photoresist.

[0042] Specifically, selective photosensitization is achieved by covering the portion that does not need to be exposed with a photomask.

[0043] Development is performed using a developer to dissolve the photoresist that reacts with light in the developer.

[0044] Process principle Figure 2 shown.

[0045] At present, under the conditions of soft baking temperature of 100℃, development time of 70s, concentration of 2.45%, and exposure machine Dose of 90mj, PFA is covered on RGB through the exposure process to form a hole pattern with a diameter of CD: (5~9) × (9~13)μm. The film thickness of PFA after exposure (THK) is: As shown in Figure 3 and Figure 4 As shown:

[0046] The invention provides a photoresist suitable for use in PFA. The photoresist can reduce exposure time and improve the production efficiency of liquid crystal display panels.

[0047] The following is a detailed introduction to the photoresist:

[0048] See also Figure 1 , shows the structural formula of the photoresist. Specifically, its structural formula is:

[0049]

[0050] Wherein, Ph represents a phenyl group, the value of m is 0 to 5, and -COOH can replace H at any position on the phenyl group, and the value of n is 1 to 6.

[0051] For the convenience of description, the position of C on the complete benzene ring that is replaced by H to form a phenyl group Ph is defined as 1, and in a clockwise direction, the numbers of C are 2, 3, 4, 5, and 6, respectively.

[0052] When m is 1 and n is 1, one of the structural formulas of CH2-Ph-COOH is:

[0053]

[0054] That is, the carboxyl group -COOH is connected to the C numbered 4.

[0055] In other embodiments, the carboxyl group -COOH can also be located at any other position, for example, connected to C numbered 2, 5 or 6. n can also be any other value between 2 and 6.

[0056] When m is 2 and n is 1, one of the structural formulas of CH2-Ph-(COOH)2 is:

[0057]

[0058] That is, the two carboxyl groups -COOH are connected to the C numbers 3 and 5 respectively.

[0059] In other embodiments, the two carboxyl groups -COOH may also be located at any other positions. For example, the structural formula in which the two carboxyl groups -COOH are connected to C numbered 5 and 6 respectively is:

[0060]

[0061] The structural formula of two carboxyl groups -COOH connected to C numbered 5 and 6 respectively is:

[0062]

[0063] The two carboxyl groups can also be connected to C numbers 2 and 3, 3 and 4, 4 and 5, 2 and 4, 4 and 6, 2 and 5, or 2 and 6. n can also be any other value from 2 to 6.

[0064] When m is 3 and n is 1, one of the structural formulas of CH2-Ph-(COOH)3 is:

[0065]

[0066] That is, three carboxyl groups -COOH are connected to C numbered 2, 5 and 6, respectively.

[0067] The three carboxyl groups -COOH can also be located at any other position of 2, 3, 4, 5 and 6. For example, three carboxyl groups -COOH are connected to C numbered 2, 3 and 4, respectively, and three carboxyl groups -COOH are connected to C numbered 3, 4 and 5, respectively.

[0068] When m is 4 and n is 1, one of the structural formulas of CH2-Ph-(COOH)4 is:

[0069]

[0070] That is, four carboxyl groups -COOH are respectively connected to C numbered 2, 3, 5 and 6. In other embodiments, the four carboxyl groups -COOH can also be located at any other position of 2, 3, 4, 5 and 6, for example, the four carboxyl groups -COOH are respectively connected to C numbered 2, 3, 4 and 5, and the four carboxyl groups -COOH are respectively connected to C numbered 3, 4, 5 and 6.

[0071] When m is 5 and n is 1, one of the structural formulas of CH2-Ph-(COOH)5 is:

[0072]

[0073] According to the analysis of the photoresist structure, the photoresist is mainly based on acrylic polymer, and the functional group -(CH2)n-Ph-(COOH)m is introduced thereon, which can accelerate the reaction rate with tetramethylammonium hydroxide (TMAH), increase the development neutralization reaction, reduce the acid substance provided by the photoreaction (strong development and weak exposure principle), and reduce the required exposure energy, thereby reducing the exposure time and improving production efficiency.

[0074] See also Figure 5 The present invention also provides a method for preparing the photoresist, comprising the following steps:

[0075] S11. Weigh an acrylic polymer and Br(CH2)n-Ph-(COOH)m at a molar ratio of 1:(1.05-1.3) and mix them evenly to obtain a mixture, wherein Ph represents a phenyl group, m is 0-5, and -COOH can replace H at any position on the phenyl group, and n is 1-6.

[0076] Specifically, the acrylic polymer has an alcohol group, and its structural formula is:

[0077]

[0078] Furthermore, the molar ratio of the acrylic polymer to the Br(CH2)n-Ph-(COOH)m is 1:1.1.

[0079] S12. Weigh sodium hydroxide according to the molar ratio of sodium hydroxide: mixture of 1: (15-20), and adjust the pH to 10-11 to obtain a reactant.

[0080] S13. Heat the above reactants under reflux at 120°C to 180°C for 18 to 30 hours in a N2 environment to obtain a crude product after the reaction is complete.

[0081] Specifically, the N2 environment is used to protect the carbon-nitrogen double bond C=N in the acrylic polymer to avoid oxidation. The reaction formula of Br(CH2)n-Ph-(COOH)m and acrylic polymer is as follows:

[0082]

[0083] That is, the alcohol group on Br(CH2)n-Ph-(COOH)m reacts to replace the H of the alcohol group.

[0084] S14. Using ethyl acetate and petroleum ether in a volume ratio of 1:3 as solvent, the crude product is recrystallized and filtered, and the liquid obtained by filtration is dried to obtain a photoresist.

[0085] The crude product contains excess but unreacted Br(CH2)n-Ph-(COOH)m and some other impurities, so it is purified by recrystallization to obtain a photoresist.

[0086] Specifically, the reaction process is described as follows, taking acrylic acid polymer and 1-bromomethyl-2,6-dibenzoic acid as raw materials and heating under reflux at 150° C. for 24 hours under N2 environment:

[0087]

[0088] At this point, the structural formula of the photoresist is:

[0089]

[0090] The inventors of the present application used the photoresist of the present application and common acrylic photoresist to perform photolithography using the same photolithography process and made a comparison. The structural formulas of the photoresist of the embodiment and the photoresist of the comparative example are as follows:

[0091] Table 1

[0092]

[0093]

[0094] The photolithography process was carried out on the embodiment and the comparative example respectively for comparison. It was found that under the same exposure machine and the same other parameters, the exposure dose of the comparative example was 110 mj, and the exposure dose of the embodiment was 90 mj.

[0095] The present invention further provides an array substrate, comprising a substrate, a color resist layer arranged on the substrate, and the above-mentioned photoresist, wherein the photoresist is arranged above the color resist layer.

[0096] The present invention further provides a display panel, comprising the above array substrate and an opposite substrate arranged opposite to the array substrate.

[0097] When the display panel is prepared with the acrylic photoresist of the comparative example, the exposure dose of the comparative example is 110 mj, the production cycle is 60 s / piece, the single machine has a daily output of 60×60×24 / 60=1440 pieces, and the monthly production capacity is 1440×30=43200 pieces.

[0098] When the display panel is prepared with the photoresist of the present application in the embodiment, the exposure dose of the embodiment is 90 mj, the production cycle is 56 s / piece, the single machine has a daily output of 60×60×24 / 56=1543 pieces, and the monthly production capacity is 1543×30=46290 pieces.

[0099] The test data of the display panels made of the photoresists of the embodiment and the comparative example are shown in the following table:

[0100] Table 2

[0101]

[0102] In Table 2, CD1 represents the short side of the opening, CD2 represents the long side of the opening, THK represents the film thickness after PFA exposure, PFAloss represents the film thickness loss after PFA development, MAC represents the macroscopic topography, and AOH represents the microscopic topography.

[0103] It can be seen from Table 2 that the performance of the display panel using the photoresist of the present application is consistent with that of the display panel of the comparative example. Therefore, the photoresist of the present application improves efficiency while ensuring product quality.

[0104] It can be seen from the above technical solution that the present invention has at least the following advantages and positive effects:

[0105] The photoresist in the present invention is mainly composed of an acrylic polymer, and a functional group - (CH2)n-Ph-(COOH)m is introduced into the main body, which can accelerate the reaction rate with tetramethylammonium hydroxide, increase the development neutralization reaction, reduce the acid substance provided by the photoreaction, and reduce the required exposure energy, thereby reducing the exposure time and improving production efficiency.

[0106] Those skilled in the art will readily appreciate other embodiments of the present invention after considering the specification and practicing the invention disclosed herein. This application is intended to cover any variations, uses or adaptations of the present invention that follow the general principles of the present invention and include common knowledge or customary techniques in the art that are not disclosed by the present invention. The specification and examples are to be considered exemplary only, and the true scope and spirit of the present invention are indicated by the following claims.

[0107] It will be appreciated that the present invention is not limited to the exact construction that has been described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof.

Claims

1. A photoresist, characterized in that: The structural formula of the photoresist is: ； Wherein, Ph represents a phenyl group, the value of m is 1 to 5, and -COOH can replace H at any position on the phenyl group, and the value of n is 1 to 6.

2. The photoresist according to claim 1, characterized in that The m is 2, and the n is 1 When, the structural formula of -CH2-Ph-(COOH)2 is: 。 3. The photoresist according to claim 1, characterized in that The m is 1, the n is 1 When, the structural formula of the -CH2-Ph-COOH is: 。 4. The photoresist according to claim 1, characterized in that The photoresist is prepared by reacting an acrylic polymer with Br(CH2)n-Ph-(COOH)m.

5. The photoresist according to claim 4, characterized in that The molar ratio of the acrylic polymer to the Br(CH2)n-Ph-(COOH)m is 1:(1.05-1.3).

6. The photoresist according to claim 4, characterized in that The molar ratio of the acrylic polymer to the Br(CH2)n-Ph-(COOH)m is 1:1.

1.

7. A method for preparing a photoresist according to any one of claims 1 to 6, characterized in that: The following steps are involved: Weighing an acrylic polymer and Br(CH2)n-Ph-(COOH)m according to a molar ratio of 1:(1.05-1.3) and mixing them uniformly to obtain a mixture; wherein Ph represents a phenyl group, the value of m is 1-5, and -COOH can replace H at any position on the phenyl group, and the value of n is 1-6; Weigh sodium hydroxide according to a molar ratio of sodium hydroxide: the mixture of 1: (15-20), and adjust the pH to 10-11 to obtain a reactant; The above reactants were heated to reflux at 120°C to 180°C under N2 environment for 18 to 30 hours, and a crude product was obtained after the reaction was completed; The crude product was recrystallized and filtered using ethyl acetate and petroleum ether in a volume ratio of 1:3 as solvent, and the liquid obtained by filtration was dried to obtain a photoresist.

8. The method for preparing a photoresist according to claim 7, characterized in that: The molar ratio of the acrylic polymer to the Br(CH2)n-Ph-(COOH)m is 1:1.

1.

9. An array substrate, characterized in that: It comprises a substrate, a color resist layer arranged on the substrate, and the photoresist according to any one of claims 1 to 6, wherein the photoresist is arranged above the color resist layer.

10. A display panel, characterized in that: It comprises the array substrate as claimed in claim 9 and an opposite substrate arranged opposite to the array substrate.

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