A black dye for positive BPDL, a BPDL layer and a preparation method thereof

Abstract

The application belongs to the technical field of preparing BPDL, and particularly relates to a black dye for positive BPDL, a BPDL layer and a preparation method thereof, wherein the black dye is composed of 6-8 parts of modified polyphenol A, 2-5 parts of metal phthalocyanine complex B, 1-2 parts of ferrous compound C and 1-2 parts of nitrogen-containing heterocyclic aromatic compound D; the BPDL layer is prepared by dispersing the organic black dye, PI resin, adhesive and photoacid generator in a solvent, pre-baking at 110-130 DEG C, exposing at 80-120 mj of exposure energy and post-baking at 230-260 DEG C. The BPDL layer prepared by the application has a certain transmittance at 365 nm in the visible light region, is close to translucent, makes the exposure energy penetrate into the deep part of the film layer, and avoids the problem of unclean development caused by too high OD value.

Description

Technical Field

[0001] This invention belongs to the field of BPDL preparation technology, specifically relating to a black dye for positive BPDL, a BPDL layer, and a method for preparing the same. Background Technology

[0002] Organic light-emitting diodes (OLEDs) are active-matrix display devices based on organic materials. Due to their advantages such as self-illumination, ultra-thinness, wide viewing angle, and fast response, they are widely used in smartphones, televisions, VR / AR, automotive displays, and flexible OLEDs. However, because OLEDs are self-emissive devices, light from adjacent pixels can be scattered through the substrate or encapsulation layer, leading to color aliasing and degrading display quality. To prevent light crosstalk, BPDL (Black Photo-Definable Light Shield) is typically chosen as a black light-blocking layer to isolate pixels and improve color purity. However, current technologies for fabricating BPDL have the following drawbacks: (1) Most existing BPDLs are achieved by adding high concentrations of black pigments (carbon black, organic black, etc.) to the photoresist. However, since pigments are usually insoluble in the medium, they often need to be uniformly dispersed in the solvent with the help of a dispersant. Due to the large particle size of the pigments, the equipment is prone to clogging during the coating process. (2) The dispersion of pigments is difficult. It usually requires grinding and dispersion or the addition of a dispersant. There are many components involved, which makes the dispersion process more complicated and cumbersome. (3) BPDLs using pigments are usually black gels. During the patterning process, due to their extremely low transmittance at the exposure wavelength (<1%), the exposure energy is difficult to penetrate deep into the film layer, resulting in the phenomenon that the holes cannot be etched. This problem is particularly prominent in positive photoresist systems.

[0003] In view of this, the present invention is hereby proposed. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a black dye for positive BPDL, a BPDL layer and a method for preparing the same, which can solve the problem of difficult development during exposure when the OD value is greater than 1 (1 μm film thickness), that is, after post-baking treatment, the OD value is ≥1.0 / μm@550nm.

[0005] To achieve the above objectives, the present invention provides the following technical solution: In a first aspect, the present invention provides a black dye for positive BPDL, comprising, by mass parts, 6-8 parts of modified polyphenolic substance A, 2-5 parts of metal phthalocyanine complex B, 1-2 parts of ferrous compound C and 1-2 parts of nitrogen-containing heterocyclic aromatic compound D.

[0006] Furthermore, the molar ratio of polyphenols to halogenated phenylenediamines in the modified polyphenolic substance A is 1:1 to 1:3. In this invention, this molar ratio may have calculation errors; typically, a ratio obtained by rounding to two decimal places is used, and such ratios are all within the scope of protection of this invention.

[0007] Specifically, polyphenolic substances are directly added to the formulation for preparing the BPDL layer, which will be washed away during development. However, by adding halophenylenediamine substances for modification and grafting, weak bonds are formed with PSPI resin, which will not be washed away and can be used to etch patterns.

[0008] Furthermore, the polyphenolic substances include, but are not limited to, one or more of tannic acid, gallic acid, caffeic acid, chlorogenic acid, propyl gallate, and resveratrol.

[0009] Furthermore, the halophenylenediamines include any one of dichloro-1,4-phenylenediamine, 2,5-dichloro-1,4-phenylenediamine, 4,4'-methylenebis(2-chloroaniline), and 2,6-dichloro-1,4-phenylenediamine.

[0010] Furthermore, the metal ion in the metal phthalocyanine complex B is a zinc ion or a copper ion; the particle size of the metal phthalocyanine complex B is ≤50nm. If the particle size of the metal phthalocyanine complex B is greater than 50nm, it can easily lead to clogging of the equipment. The main function of the metal phthalocyanine complex B is to block the red light region.

[0011] Furthermore, the ferrous compound C includes, but is not limited to, one of ferrous acetylacetone, ferrous sulfate, and ferrous chloride.

[0012] Furthermore, the nitrogen-containing heterocyclic aromatic compound D includes, but is not limited to, one of carbazole and pyrrole.

[0013] In a second aspect, the present invention provides a BPDL layer, comprising, by mass parts, 9-17 parts of organic black dye, 7-15 parts of PI resin, 0.5-2 parts of crosslinking agent, 1-2 parts of photoacid generator, and 76-88 parts of organic solvent. The black dye mentioned above is a black dye used for positive BPDL.

[0014] Specifically, the photoacid generator includes iodonium salts, such as diphenyliodonium hexafluoroantimonate, thionium salts, such as triphenylthionium trifluoromethanesulfonate, and sulfonates, such as N-hydroxynaphthalimide trifluoromethanesulfonate.

[0015] The crosslinking agent is one or more of hexamethylol melamine-hydroxyalkylpyrrolidone (HMX-HAP), trimethylol melamine-bisphenol A (TMX-BIP-A), and MW-390.

[0016] Furthermore, the organic solvent is one or more of propylene glycol methyl ether (PGEM), ethyl lactate (EL), and γ-butyrolactone (GBL).

[0017] It should be noted that the amounts of the above-mentioned raw materials only need to be within the ranges described above. For example, modified polyphenol A can be 6 parts, 7 parts, 8 parts, etc.; metal phthalocyanine complex B can be 2 parts, 2.5 parts, 3 parts, 3.5 parts, 4 parts, 4.5 parts, 5 parts, etc.; ferrous compound C can be 1 part, 1.5 parts, 2 parts, etc.; nitrogen-containing heterocyclic aromatic compound D can be 1 part, 1.5 parts, 2 parts, etc.; correspondingly, organic black dye can be 9 parts, 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, 15 parts, 16 parts, 17 parts. The PI resin can be 7 parts, 8 parts, 9 parts, 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, 15 parts, etc.; the crosslinking agent can be 0.5 parts, 1 part, 1.5 parts, 2 parts, etc.; the photoacid generating agent can be 1 part, 1.5 parts, 2 parts, etc.; and the organic solvent can be 76 parts, 77 parts, 78 parts, 79 parts, 80 parts, 81 parts, 82 parts, 83 parts, 84 parts, 85 parts, 86 parts, 87 parts, 88 parts, etc., which will not be listed here.

[0018] Thirdly, the present invention provides a method for preparing a BPDL layer, comprising the following steps: first, dispersing the organic black dye, PI resin, crosslinking agent, and photoacid generator in an organic solvent; then, pre-baking at 110-130°C and post-baking at 230-260°C with an exposure energy of 80-120 mJ to obtain a BPDL layer.

[0019] Specifically, the method for preparing the BPDL layer includes the following steps: S1. Disperse PI resin, crosslinking agent, and photoacid generator in an organic solvent and stir for 2-4 hours to obtain PSPI precursor solution; S2. Disperse the modified polyphenolic substance A in the PSPI precursor solution obtained in S1, and react at 80-90℃ for 5-6 hours to obtain a PSPI solution containing the modified polyphenolic substance. S3. Under N2 protection, ferrous compound C is added to the PSPI solution containing modified polyphenols obtained in S2, and the reaction is carried out at 23-27℃ for 3-4 hours to obtain a PSPI solution containing modified complex. S4. After grinding the metal phthalocyanine complex B and the nitrogen-containing heterocyclic aromatic compound D in a mortar for 1-3 hours, disperse them in the PSPI solution containing the modified complex obtained in S3, and then sonicate for 1-2 hours to obtain a PSPI solution containing black dye. The purpose of the grinding process here is to use the mechanical forces (shear, pressure, friction) generated by grinding to induce solid-state reactions and promote intermolecular interactions. S5. The PSPI solution containing black dye obtained in S4 is filtered and spin-coated onto the glass surface. After pre-baking at 110-130℃ and post-baking at 230-260℃ with an exposure energy of 80-120mJ, the patterned BPDL layer is prepared.

[0020] It should be noted that the parameters involved in each of the above steps only need to be within the ranges mentioned above. For example, the stirring time in S1 can be 2h, 2.5h, 3h, 3.5h, 4h, etc.; the reaction temperature in S2 can be 80℃, 81℃, 82℃, 83℃, 84℃, 85℃, 86℃, 87℃, 88℃, 89℃, 90℃, etc., and the reaction time can be 5h, 5.5h, 6h, etc.; the reaction temperature in S3 can be 23℃, 24℃, 25℃, 26℃, 27℃, etc., and the reaction time can be 3h, 3.5h, 4h, etc.; the grinding time in S4 can be 1h, 1.5h, 2h, 2.5h, 3h, etc. The ultrasonic vibration time can be 1h, 1.5h, 2h, etc.; the pre-drying temperature in S5 can be 110℃, 115℃, 120℃, 125℃, 130℃, etc., and the post-drying temperature can be 230℃, 235℃, 240℃, 245℃, 250℃, 255℃, 260℃, etc.; they will not be listed here one by one.

[0021] Compared with the prior art, the technical solution provided by the present invention has the following beneficial effects: 1. This invention modifies polyphenolic substances in dyes with halophenylenediamine to obtain compounds with phenolic hydroxyl and amino groups. Since the amino group can undergo an imidization reaction with the unimidized acid anhydride in PSPI, the black dye is cured in PSPI resin. Before development, the phenolic hydroxyl groups in the polyphenolic substances are not completely oxidized. At this time, the sample still has a certain transmittance in the visible light region of 365nm, which is close to semi-transparent. This allows the exposure energy to penetrate deep into the film layer and avoids unclean development caused by too high OD value. In the post-baking stage, the phenolic hydroxyl groups in the modified polyphenolic substances are oxidized to anthraquinones, which polymerize to form black substances, and the film surface turns black, meeting the OD value requirements and reducing the complexity of the process.

[0022] (2) Based on the modified polyphenolic substances, the present invention introduces metal phthalocyanine complexes, ferrous compounds and nitrogen-containing heterocyclic aromatic compounds; ferrous compounds can crosslink with polyphenolic substances that are not replaced by phenylenediamine in the system to form black complexes and enhance the stability of dyes; nitrogen-containing heterocyclic aromatic compounds, as electron donors, can prolong the excited state lifetime of zinc phthalocyanine and improve the photosensitivity efficiency. At the same time, zinc phthalocyanine (ZnPC) can absorb red light / near infrared light and further enhance blackness by combining with polyphenol-Fe.

[0023] (3) Most of the dyes used in this invention are small molecules with small particle size, which will not cause equipment blockage during coating; and the dye components in this invention do not require bead milling or dispersing agents, making the preparation method simple. Attached Figure Description

[0024] Figure 1 The graph shows the experimental data results of the transmission spectra of the pre-baked samples measured in Examples 1-4; Figure 2 The figures show the experimental data results of the transmission spectra of the unlithographic post-baked samples obtained in Examples 1-4. Detailed Implementation

[0025] Exemplary embodiments will be described in detail below. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Rather, they are merely examples consistent with some aspects of the invention as detailed in the appended claims.

[0026] Example 1 This embodiment 1 provides a method for preparing a BPDL layer, wherein the required substances are in parts by mass, and 1g corresponds to 1 part, and includes the following steps: S1. Dissolve 10 parts of PI resin, 0.5 parts of crosslinking agent HMX-HAP, and 2 parts of photoacid-producing agent in 80 parts of organic solvent PGME, and stir for 2 hours to obtain PSPI precursor solution. S2. 5g of chlorogenic acid and 2.5g of 2,5-dichloro-1,4-phenylenediamine (the molar ratio of chlorogenic acid to 2,5-dichloro-1,4-phenylenediamine is 1:1) are uniformly dispersed in the PSPI precursor solution obtained in S1. The reaction is carried out at 80℃ for 5h to obtain a PSPI solution containing modified chlorogenic acid. The reaction process is shown below: S3. Under N2 protection, two parts of ferrous acetylacetone were added to the PSPI solution containing modified chlorogenic acid obtained in S2, and the reaction was carried out at 25°C for 3 hours; this yielded a solution containing modified chlorogenic acid-Fe 2+ PSPI solution of the complex; S4. Grind 2 parts ZnPC and 1 part carbazole evenly in a mortar for 1.5 hours, then disperse them in the modified chlorogenic acid-Fe mixture obtained in S3. 2+ The PSPI solution containing the complex was sonicated for 1 hour to obtain a PSPI solution containing black dye. S5. The PSPI solution containing black dye obtained in S4 is filtered through a 0.5 μm filter and then spin-coated onto a glass surface. The film thickness is controlled to be about 1.7 μm. After pre-baking at 120°C, the film is exposed at 80 mJ using a mask. After development with TMAH developer for 60 seconds, the film is post-baked at 250°C for 60 minutes to prepare a patterned BPDL layer.

[0027] Example 2 This embodiment provides a method for preparing a BPDL layer, wherein the required substances are specified by mass parts, with 1g corresponding to 1 part, and includes the following steps: S1. Dissolve 10 parts of PI resin, 0.5 parts of crosslinking agent HMX-HAP, and 2 parts of photoacid-producing agent in 80 parts of organic solvent PGME, and stir for 2 hours to obtain PSPI precursor solution. S2. 6 g of tannic acid and 1.9 g of 4,4'-methylenebis(2-chloroaniline) (the molar ratio of tannic acid to 4,4'-methylenebis(2-chloroaniline) is 1:2) are uniformly dispersed in the PSPI precursor solution obtained in S1. The reaction is carried out at 80 °C for 5 h to obtain a PSPI solution containing modified tannic acid. The reaction process is shown below: S3. Under N2 protection, two parts of ferrous acetylacetone were added to the PSPI solution containing modified tannic acid obtained in S2, and the reaction was carried out at 25°C for 3 hours; this yielded a solution containing modified tannic acid-Fe 2+ PSPI solution of the complex; S4. Grind 2 parts CuPC and 1 part carbazole in a mortar for 1.5 hours, then disperse the mixture in the modified tannic acid-Fe mixture obtained in S2. 2+ The PSPI complex solution was sonicated for 1 hour to obtain a PSPI solution containing black dye. S5. The PSPI solution containing black dye obtained in S3 is filtered through a 0.5 μm filter and then spin-coated onto a glass surface. The film thickness is controlled to be about 1.7 μm. After pre-baking at 120°C, the film is exposed at 80 mJ using a mask. After development with TMAH developer for 60 seconds, the film is post-baked at 250°C for 60 minutes to prepare a patterned BPDL layer.

[0028] Example 3 This embodiment provides a method for preparing a BPDL layer, wherein the required substances are specified by mass parts, with 1g corresponding to 1 part, and includes the following steps: S1. Dissolve 10 parts of PI resin, 0.5 parts of crosslinking agent HMX-HAP, and 2 parts of photoacid-producing agent in 80 parts of organic solvent PGME, and stir for 2 hours to obtain PSPI precursor solution. S2. 6g of tannic acid and 1.9g of 2,5-dichloro-1,4-phenylenediamine (the molar ratio of tannic acid to 2,5-dichloro-1,4-phenylenediamine is 1:3) are uniformly dispersed in the PSPI precursor solution obtained in S1. The reaction is carried out at 80℃ for 5 hours to obtain a PSPI solution containing modified tannic acid. The reaction process is shown below: S3. Under N2 protection, 2 parts of ferrous sulfate were added to the PSPI solution containing modified tannic acid obtained in S2, and the reaction was carried out at 25°C for 3 hours; a modified tannic acid-Fe2+ solution was obtained. 2+ PSPI solution of the complex; S4. Grind 2 parts ZnPC and 1 part carbazole in a mortar for 1.5 hours, then disperse the mixture in the modified tannic acid-Fe mixture obtained in S3. 2+ The PSPI solution containing the complex was sonicated for 1 hour to obtain a PSPI solution containing black dye. S5. The PSPI solution containing black dye obtained in S4 is filtered through a 0.5 μm filter and then spin-coated onto a glass surface. The film thickness is controlled to be about 1.7 μm. After pre-baking at 120°C, the film is exposed at 80 mJ using a mask. After development with TMAH developer for 60 seconds, the film is post-baked at 250°C for 60 minutes to prepare a patterned BPDL layer.

[0029] Example 4 This embodiment provides a method for preparing a BPDL layer, wherein the required substances are specified by mass parts, with 1g corresponding to 1 part, and includes the following steps: S1. Dissolve 10 parts of PI resin, 0.5 parts of crosslinking agent HMX-HAP, and 2 parts of photoacid-producing agent in 80 parts of organic solvent NMP and stir for 2 hours to obtain PSPI precursor solution. S2. 4g of chlorogenic acid and 4g of 4,4'-methylenebis(2-chloroaniline) (the molar ratio of chlorogenic acid to 4,4'-methylenebis(2-chloroaniline) is 1:1.3) are uniformly dispersed in the PSPI precursor solution obtained in S1. The reaction is carried out at 80℃ for 5 hours to obtain a PSPI solution containing modified chlorogenic acid. The reaction process is shown below: S3. Under N2 protection, 2 parts of ferrous sulfate were added to the PSPI solution containing modified chlorogenic acid obtained in S2, and the reaction was carried out at 25°C for 3 hours; this yielded a solution containing modified chlorogenic acid-Fe 2+ PSPI solution of the complex; S4. Grind 2 parts ZnPC and 1 part pyrrole in a mortar for 1 hour, then disperse them in the modified chlorogenic acid-Fe obtained in S3. 2+ The PSPI solution containing the complex was sonicated for 1 hour to obtain a PSPI solution containing black dye. S5. The PSPI solution containing black dye obtained in S4 is filtered through a 0.5 μm filter and then spin-coated onto a glass surface. The film thickness is controlled to be about 1.7 μm. After pre-baking at 120°C, the film is exposed at 80 mJ using a mask. After development with TMAH developer for 60 seconds, the film is post-baked at 250°C for 60 minutes to prepare a patterned BPDL layer.

[0030] Comparative Example 1 The difference between this comparative example and Example 2 is that this comparative example does not contain ZnPC and carbazole.

[0031] Comparative Example 2 The difference between this comparative example and Example 3 is that this comparative example does not contain 2,5-dichloro-1,4-phenylenediamine.

[0032] Comparative Example 3 The difference between this comparative example and Example 4 is that in this comparative example, chlorogenic acid is 2g, 4,4'-methylenebis(2-chloroaniline) is 3g, and the molar ratio of chlorogenic acid to 4,4'-methylenebis(2-chloroaniline) is 1:2.

[0033] Comparative Example 4 The difference between this comparative example and Example 4 is that this comparative example does not contain ferrous sulfate and pyrrole, and the grinding step is omitted.

[0034] Comparative Example 5 The difference between this comparative example and Example 3 is that in this comparative example, 6g of tannic acid and 0.4g of 2,5-dichloro-1,4-phenylenediamine are used, and the molar ratio of tannic acid to 2,5-dichloro-1,4-phenylenediamine is 1.6:1.

[0035] The raw material formulations of Examples 1-4 and Comparative Examples 1-5 are shown in Table 1 below: Table 1. Raw material ratios for Examples 1-4 and Comparative Examples 1-5 To verify the efficacy of the present invention, the BPDL layers obtained in Examples 1-4 and Comparative Examples 1-5 were subjected to BPDL photoresist performance tests, including the following aspects: (1) Color before / after baking: Subjectively observe the color of the film surface before and after baking. If the color of the film surface after baking is black, it is considered qualified; otherwise, it is unqualified.

[0036] (2) OD value after drying: The transmittance of the whole film after drying is tested by spectrophotometer, and then the OD value is calculated according to the formula: OD value = Log(1 / T); After obtaining the OD value result, divide it by the film thickness to obtain the OD value per unit film thickness.

[0037] (3) Development performance: Whether the unexposed BPDL film can remain undissolved in TMAH developer for 90 seconds.

[0038] (4) Resolution: The smallest aperture that can be etched on the film surface after exposure and development.

[0039] The BPDL layers obtained in Examples 1-4 and Comparative Examples 1-5 were subjected to post-baking experiments. The post-baking colors were mainly black, blue, and gray samples. The experimental results are as follows: Figure 1-2 As shown in Table 2.

[0040] Table 2 shows the results of the post-baking experiments in Examples 1-4 and Comparative Examples 1-5. Analysis showed that the unit OD values ​​of the samples in Examples 1 to 4 were all >1. The transmittance of Examples 1 to 4 at 550nm was 0.7%, 0.4%, 0.1%, and 1.6%, respectively, and the development performance was all above 90s.

[0041] Figure 1 Examples 1-4 show a transmittance close to 0 in the visible light wavelength range of 380-700nm, indicating a high OD value. Comparative Examples 3 and 4 show high transmittance in the 400-500nm range; Comparative Example 1 shows high transmittance in the 500-700nm range, resulting in a low OD value. Although Comparative Examples 2 and 5 meet the requirement of OD value > 1, they experience film detachment problems during development, indicating that using unmodified polyphenolic compounds or a molar ratio of polyphenolic substances to halophenylenediamines greater than 1:1 in the formulation cannot meet the development requirements.

[0042] Although Comparative Example 1 met the development requirements, its transmittance at 550nm was >10%, and its OD value did not meet the usage requirements. Although Comparative Examples 3 and 4 had relatively low transmittance at 550nm (0.1% for Comparative Example 3 and 0.7% for Comparative Example 4), the low amount of modified polyphenols added in the whole system resulted in higher transmittance at 450nm (blue light region) after baking (28.6% for Comparative Example 3 and 40% for Comparative Example 4), meaning that the overall transmittance was still relatively high (the OD value was relatively low).

[0043] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention.

[0044] It should be understood that the present invention is not limited to the content already described above, and various modifications and changes can be made without departing from its scope. The scope of the present invention is limited only by the appended claims.

Claims

1. A black dye for positive BPDL, characterized in that, By mass, it consists of 6-8 parts of modified polyphenolic substance A, 2-5 parts of metal phthalocyanine complex B, 1-2 parts of ferrous compound C and 1-2 parts of nitrogen-containing heterocyclic aromatic compound D; The molar ratio of polyphenols and halogenated phenylenediamines in the modified polyphenol A is 1:1 to 1:

3. The polyphenolic substances include tannic acid or chlorogenic acid; The halophenylenediamines include any one of 2,5-dichloro-1,4-phenylenediamine, 4,4'-methylenebis(2-chloroaniline), and 2,6-dichloro-1,4-phenylenediamine; The metal ion in the metal phthalocyanine complex B is a zinc ion or a copper ion. The particle size of the metal phthalocyanine complex B is ≤50nm; The ferrous compound C includes ferrous acetylacetone or ferrous sulfate; The nitrogen-containing heterocyclic aromatic compound D includes either carbazole or pyrrole.

2. A BPDL layer, characterized in that, By mass, it includes 9-17 parts organic black dye, 7-15 parts PI resin, 0.5-2 parts crosslinking agent, 1-2 parts photoacid generator, and 76-88 parts organic solvent. The organic black dye is the black dye according to claim 1.

3. The BPDL layer according to claim 2, characterized in that, The organic solvent is one or more of propylene glycol methyl ether, ethyl lactate, and γ-butyrolactone.

4. A method for preparing a BPDL layer as described in any one of claims 2-3, characterized in that, The steps include: First, the organic black dye, PI resin, crosslinking agent, and photoacid generator are uniformly dispersed in an organic solvent, and then the BPDL layer is prepared after pre-baking, exposure, and post-baking.

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