A photoresist cleaning agent for micro-led chip cleaning, a preparation method and application thereof

Abstract

The application provides a photoresist cleaning agent for Micro-LED chip cleaning, a preparation method and application, the photoresist cleaning agent for Micro-LED chip cleaning comprises the following components in parts by mass: quaternary ammonium base 5-15 parts; alcohol amine 20-50 parts; polar solvent 45-75 parts; N,N'-dihydroxy hydroquinone imine 0.01-0.1 parts; sorbitol acetal derivative 0.1-1 parts.The photoresist cleaning agent for Micro-LED chip cleaning comprises quaternary ammonium base and alcohol amine, and combines the double hydrogen bond bridging action of N,N'-dihydroxy hydroquinone imine and sorbitol acetal derivative, constructs a dense and stable three-dimensional hydrogen bond network, effectively reduces the effective activity of free OH ‑ and alcohol amine, thereby realizing the protection of the Cu electrode under high-temperature cleaning conditions, and having an ultra-low corrosion rate.

Description

Technical Field

[0001] This invention relates to photoresist cleaning agent technology, and more particularly to a photoresist cleaning agent for cleaning Micro-LED chips, its preparation method, and its application. Background Technology

[0002] As new display technologies continue to iterate towards higher resolution and higher brightness, Micro-LED, with its advantages of self-illumination and long lifespan, has become the core development direction of next-generation display technology. Electrode patterning is crucial for Micro-LED production. Cu, due to its excellent conductivity and low cost, is gradually replacing Au and Al as the mainstream electrode material. However, Cu is chemically reactive and easily corroded during photoresist stripping, leading to device defects and reduced yield, which has become a major obstacle to its large-scale application. Traditional stripping solutions are designed for Si-based semiconductors and lack Cu protection mechanisms. Solvent-based stripping solutions easily corrode Cu, leaving residues, while water-based stripping solutions have low stripping efficiency and cannot meet the requirements of refined processes. Since Micro-LED chips typically use III-V compound semiconductor substrates and refined Cu electrode patterns, traditional Si-based semiconductor cleaning agents cannot simultaneously ensure compatibility with III-V materials and protection of Cu electrodes. The accelerated industrialization of Micro-LED has driven the development of specialized stripping solutions.

[0003] In the early stages of Micro-LED development, two main types of solutions were used: the first type was a strongly alkaline organic amine system, which relied on hydroxylamine, monoethanolamine, etc., to swell and strip the photoresist, but it severely corroded copper, causing the micron-sized copper electrode to oxidize or even dissolve rapidly; the second type was an acidic oxidation system, such as a sulfuric acid-hydrogen peroxide mixture, which could remove some residues, but its intense oxidation caused a sharp increase in the roughness of the copper surface and severely eroded the sidewalls of light-emitting materials such as GaN, resulting in a catastrophic decrease in luminous efficiency.

[0004] To address the three unique challenges of Micro-LEDs—"micron-structure protection," "III-V material compatibility," and "mass transfer interface cleaning"—composite corrosion inhibitors have been developed. For example, patent CN112415869A discloses a compatible and environmentally friendly aqueous photoresist stripping solution applicable to various metal processes, comprising: alkanolamines, alcohol ethers, ultrapure water, benzotriazole additive A, amino acid additive B, and additive C such as polyol phosphonate (PAPE). This solution utilizes strong alkali swelling and strong oxidative decomposition to strip the photoresist. Simultaneously, by leveraging the synergistic combination of benzotriazole derivatives and organophosphonates, a dense and self-healing molecular protective film is formed on the metal film surface, effectively inhibiting the corrosion of the underlying metal wiring by the stripping solution during the stripping process.

[0005] Another patent, CN111356759B, provides a stripping agent composition containing ascorbic acid, hydroxylamine derivatives, and benzotriazole corrosion inhibitors. This composition removes photoresist and dry etching residues while preventing oxidative damage to the substrate. Optimization of physical properties: By adding specific surfactants, the surface tension of the solution is reduced, significantly improving its wetting and penetration capabilities for high aspect ratio microstructures, and reducing chip detachment or cleaning residue caused by liquid surface tension.

[0006] However, the protective film formed by the benzotriazole corrosion inhibitors used in the aforementioned patents is essentially a metastable physical adsorption / coordination polymer layer, rather than a perfectly chemically bonded layer. At higher temperatures (>60°C) or prolonged immersion, this protective film will slowly dissolve or reform. At grain boundaries, step edges, and defects on the copper surface, the protective film is often thin or porous, becoming preferential sites for corrosion. While this type of technology can suppress corrosion rates to the 1-10 Å / min level, this level of protection is insufficient for future ultra-thin copper structures with nodes of 5 nanometers and below. Summary of the Invention

[0007] The purpose of this invention is to address the problem in existing photoresist cleaning agents where the protective film of the inhibitor easily dissolves and reorganizes under high temperature or prolonged immersion, resulting in poor Cu protection and easy corrosion. This invention proposes a photoresist cleaning agent for Micro-LED chip cleaning. This photoresist cleaning agent comprises a quaternary ammonium base and an alkanolamine, and combines the double hydrogen bond bridging effect of N,N'-dihydroxypyromellitic acid imine and sorbitan acetal derivative to construct a dense and stable three-dimensional hydrogen bond network, effectively reducing free OH groups. - The effective activity of amines and alkanolamines is utilized to achieve ultra-low corrosion rate protection for Cu electrodes under high-temperature cleaning conditions.

[0008] It should be noted that, in this invention, unless otherwise specified, the specific meaning of "comprising" in relation to composition and description includes both open-ended meanings such as "comprising," "including," etc., and closed-ended meanings such as "composed of," "consisting of," etc., and similar meanings.

[0009] To achieve the above objectives, the technical solution adopted by the present invention is: a photoresist cleaning agent for cleaning Micro-LED chips, comprising the following components by weight:

[0010] 5-15 parts of quaternary ammonium base;

[0011] 20-50 parts of alcohol amine;

[0012] 45-75 parts of polar solvent;

[0013] 0.01-0.1 parts of N,N'-dihydroxypyromellitic acid imine;

[0014] 0.1-1 part of sorbitol acetal derivative.

[0015] Furthermore, the quaternary ammonium base is selected from one or more of tetramethylammonium hydroxide, choline, methyltriethylammonium hydroxide, trimethylethylammonium hydroxide, tetrapropylammonium hydroxide, and tetraethylammonium hydroxide.

[0016] Furthermore, the quaternary ammonium base is preferably tetramethylammonium hydroxide and / or choline.

[0017] Furthermore, the quaternary ammonium base is 6-11 parts.

[0018] Further, the alkanolamine is selected from one or more of monoethanolamine, isopropanolamine, diethanolamine, triethanolamine, N-methyldiethanolamine, methylmonoethanolamine, 2-amino-2-methyl-1-propanol, 2-diethylaminoethanol and hydroxyethylethylenediamine.

[0019] Furthermore, the alkanolamine is preferably monoethanolamine and / or methylmonoethanolamine.

[0020] Furthermore, the alkanolamine is more preferably a monoethanolamine.

[0021] Furthermore, the amount of the alcohol amine is 30-44 parts.

[0022] Furthermore, the mass ratio of the alkanolamine to the quaternary ammonium base is 2-6:1.

[0023] Furthermore, the preferred mass ratio of the alkanolamine to the quaternary ammonium base is 4:1.

[0024] The corrosion of copper in alkaline solutions is essentially the oxidation and dissolution of copper to form soluble copper ammonium complex ions. For quaternary ammonium bases, excess OH-... - It will dissolve the copper passivation film, forming [Cu(OH4)] 2- This promotes corrosion. For alkanolamines, the molecule contains -NH2 and -OH groups; excess alkanolamines can form soluble complexes with copper ions (such as [Cu(MEA)2)). 2- This also promotes corrosion.

[0025] In the quaternary ammonium base and alkanolamine system of this application, hydrogen bonds can be formed between the two, such as R-NH2... - OH, ROH... - O -H, HO - HNR, H-O - ...HOR, R-NH2...HOR, ROH...HNR, etc., this invention optimizes the ratio of quaternary ammonium base to alcoholamine, so that free OH... -By maximizing the formation of hydrogen bonds with alcoholamines, the effective activity of both is reduced, thereby reducing the attack on Cu.

[0026] Furthermore, the polar solvent is selected from one or more of diethylene glycol monobutyl ether, propylene glycol monobutyl ether, propylene glycol monomethyl ether, N,N-dimethylformamide, dimethyl sulfoxide, N-ethylpyrrolidone, 1,3-dimethyl-2-imidazolinone, N,N-dimethylpropionamide, N-methylcaprolactam, N-butylpyrrolidone, and N,N-dimethylisobutyramide.

[0027] Furthermore, the polar solvent is preferably one or more of diethylene glycol monobutyl ether, N,N-dimethylformamide, and dimethyl sulfoxide.

[0028] Furthermore, the polar solvent is more preferably dimethyl sulfoxide.

[0029] Furthermore, the polar solvent is 45-60 parts.

[0030] Further, the N,N'-dihydroxypyromellitic acid imine is 0.02-0.05 parts.

[0031] Furthermore, the sorbitol acetal derivative is selected from 1,3:2,4-dibenzyl-D-sorbitol and / or 1,3:2,4-di(3,4-dimethylbenzyl)-D-sorbitol.

[0032] Furthermore, the sorbitol acetal derivative is preferably 1,3:2,4-bis(3,4-dimethylbenzyl)-D-sorbitol.

[0033] Furthermore, the mass ratio of the sorbitol acetal derivative to N,N'-dihydroxypyromellitic acid imine is 8-12:1.

[0034] Furthermore, the preferred mass ratio of the sorbitol acetal derivative and N,N'-dihydroxypyromellitic acid imine is 10:1.

[0035] Furthermore, the sorbitol acetal derivative is present in amounts of 0.2-0.5 parts.

[0036] Another object of the present invention discloses a method for preparing a photoresist cleaning agent for cleaning Micro-LED chips, comprising the following steps:

[0037] N,N'-dihydroxypyromellitic acid imine is added to a polar solvent and stirred until completely dissolved. Then, a quaternary ammonium base and an alkanolamine are added and stirred again until completely dissolved. Finally, a sorbitol acetal derivative is added and heated at 55-65°C with stirring until completely dissolved to obtain the photoresist cleaning agent for Micro-LED chip cleaning.

[0038] Furthermore, the stirring time is independently 30-60 minutes.

[0039] Another objective of this invention is to disclose the application of a photoresist cleaner for cleaning Micro-LED chips in the field of Micro-LED chip cleaning.

[0040] Furthermore, the method for cleaning Micro-LED chips using photoresist cleaning agents is as follows:

[0041] S1. Immerse the Micro-LED chip in a photoresist cleaning solution for Micro-LED chip cleaning at 60-90℃ to obtain the immersed chip;

[0042] S2. Rinse the soaked chip to complete the cleaning of the Micro-LED chip.

[0043] Furthermore, the soaking time in S1 is 10-40 minutes.

[0044] Furthermore, rinse at least twice in S2.

[0045] Furthermore, ultrapure water is used for rinsing in S2.

[0046] The photoresist cleaning agent, preparation method, and application for cleaning Micro-LED chips of this invention have the following advantages compared with the prior art:

[0047] 1) This invention optimizes the ratio of quaternary ammonium base to alcoholamine, so that free OH- - It can maximize the formation of hydrogen bonds with alcoholamines, thereby effectively reducing the effective activity of both and significantly weakening the free OH groups in the system. - The chemical attack ability of excessive alkanolamine on the copper surface is thus used to inhibit the corrosion of Cu.

[0048] 2) The N,N'-dihydroxypyromellitic acid imine introduced in this invention can make the hydrogen bond network of the entire system more compact and stable through its stronger hydrogen bond donor / acceptor ability. Simultaneously, N,N'-dihydroxypyromellitic acid imine can form multiple hydrogen bonds with quaternary ammonium bases and alkanolamines in the system, and all hydrogen bond sites are distributed on a rigid aromatic ring backbone with small site spacing and high density. It can simultaneously form hydrogen bonds with 2-3 system molecules, easily constructing a three-dimensional dense hydrogen bond network, thereby making the components of the system tightly bound together and significantly improving the overall system homogeneity and hydrogen bond strength.

[0049] 3) To further enhance the stability and strength of the hydrogen bond network, this invention also incorporates sorbitol acetal derivatives. These substances have abundant hydrogen bond donor / acceptor sites, enabling them to form intermolecular hydrogen bond associations with N,N'-dihydroxypyromellitic acid imine, while simultaneously bridging the quaternary ammonium base and the alkanolamine. This achieves a dual hydrogen bond bridging effect of "imine + auxiliary agent," further improving the overall strength and structural stability of the hydrogen bond network and reducing the Cu corrosion rate.

[0050] 4) The three-dimensional hydrogen bond network constructed in this invention maintains a dense and stable structure even under high-temperature cleaning conditions (60-90℃), achieving ultra-low corrosion rate protection at high temperatures. This overcomes the problem that traditional corrosion inhibitors easily dissolve or recombine their protective film at temperatures above 60℃, leading to corrosion.

[0051] In summary, this invention significantly inhibits copper corrosion and solves the technical problem of protective film failure under high temperature and long-term treatment by optimizing the ratio of quaternary ammonium base to alkanolamine and introducing N,N'-dihydroxypyromellitic acid imine and sorbitol acetal derivative to construct a dual-enhanced three-dimensional hydrogen bond network. Attached Figure Description

[0052] Figure 1 Dark-field image of an 8000 Å Cu sheet under a microscope, magnified 50 times, before immersion;

[0053] Figure 2 Bright-field image of an 8000 Å Cu sheet under a microscope, magnified 50 times, before immersion;

[0054] Figure 3 Dark-field image magnified 50x under a microscope of an 8000 Å Cu wafer after being soaked in the photoresist cleaning agent prepared in Example 1;

[0055] Figure 4 Bright-field image under a microscope at 50x magnification of an 8000 Å Cu wafer after immersion in the photoresist cleaning agent prepared in Example 1;

[0056] Figure 5 Dark-field image magnified 50x under a microscope of an 8000 Å Cu wafer soaked in the photoresist cleaning agent prepared for Comparative Example 1;

[0057] Figure 6 Bright-field image of an 8000 Å Cu wafer soaked in the photoresist cleaning agent prepared for Comparative Example 1, magnified 50 times under a microscope. Detailed Implementation

[0058] The present invention will be further described below with reference to embodiments. The description of the technical features described below is based on representative embodiments and specific examples of the present invention, but the present invention is not limited to these embodiments and specific examples. It should be noted that:

[0059] Unless otherwise stated, all units used in this specification are international standard units, and all numerical values ​​and ranges appearing in this invention should be understood to include systematic errors that are unavoidable in industrial production.

[0060] In this specification, the range of values ​​referred to as "value A to value B" refers to the range including the endpoint values ​​A and B.

[0061] In this specification, the numerical range indicated by "above" or "below" refers to the numerical range that includes the stated number.

[0062] In this specification, the word "may" has two meanings: to perform a certain process and not to perform a certain process.

[0063] In this specification, the terms "optional" or "optional" are used to indicate the use or omission of certain substances, components, procedures, application conditions, etc.

[0064] In this instruction manual, when "room temperature" or "room temperature" is used, the temperature can be 15-25℃.

[0065] Unless otherwise specified, all reagents or instruments used in this instruction manual are commercially available products.

[0066] Examples 1-8

[0067] Examples 1-8 disclose various photoresist cleaning agents for cleaning Micro-LED chips, and their preparation methods are as follows:

[0068] Step 1. Prepare quaternary ammonium base, alkanolamine, polar solvent, N,N'-dihydroxypyromellitic acid imine, and sorbitol acetal derivative according to the specified ratio;

[0069] Step 2. Add the polar solvent to the container, then add N,N'-dihydroxypyromellitic acid imine, and stir for 60 minutes until completely dissolved;

[0070] Step 3. Add quaternary ammonium base and alkanolamine, and continue stirring for 30 minutes until completely dissolved.

[0071] Step 4. Add sorbitol acetal derivative, heat in a water bath to 60°C, and stir for 60 minutes until completely dissolved to obtain the photoresist cleaning agent.

[0072] The components and formulation of the photoresist cleaning agent used for cleaning Micro-LED chips are shown in Table 1.

[0073] Table 1 Examples 1-8

[0074]

[0075] Comparative Examples 1-3

[0076] Comparative Examples 1-3 disclose various photoresist cleaning agents, which are prepared in the same way as in Example 1. The components and formulations contained therein are shown in Table 2.

[0077] Table 2 Comparative Examples 1-3

[0078]

[0079] The photoresist cleaning agents of Examples 1-8 and Comparative Examples 1-3 were tested respectively. The test methods and results are as follows:

[0080] The photoresist cleaning agent was tested using a four-probe method to assess the corrosion performance of different photoresist cleaning agents on metallic Cu.

[0081] The specific testing method is as follows:

[0082] 1. Cut the 8000 Å Cu slice into 2×2 cm pieces. 2 Size, using a four-probe measurement to measure the thickness of the Cu wafer before immersion in photoresist cleaning agent.

[0083] 2. [The remaining text appears to be incomplete and fragmented, possibly due to OCR errors. A more accurate translation would require the full context.] 2 An 8000 Å Cu wafer was immersed in a cleaning agent at 85 °C for 60 min. The thickness of the Cu wafer after immersion in the photoresist cleaning agent was then measured using the four-probe method.

[0084] 3. According to the following formula

[0085] Corrosion rate = (Cu sheet thickness before immersion - Cu sheet thickness after immersion) / Immersion time

[0086] The corrosion rates (Å / min, also known as "etching rate") of each cleaning agent were calculated to examine the corrosion rates of metals by different cleaning agents.

[0087] The test results are shown in Table 3:

[0088] Table 3 Test Results

[0089]

[0090] Based on the test results in Table 3, it can be seen that the photoresist cleaning agent used for Micro-LED chip cleaning in this application has a low corrosion rate on Cu. Relatively speaking, in Example 7, the mass ratio of sorbitol acetal derivative to N,N'-dihydroxypyromellitic acid imine is greater than 12:1; in Example 8, because the mass ratio of alkanolamine to quaternary ammonium base is less than 4:1, both result in a higher free OH content. - The increased effective activity of alcohol amines leads to a slight increase in the corrosion rate;

[0091] Comparative Example 1, due to the absence of N,N'-dihydroxypyromellitic acid imine, had free OH- - The increased activity of sorbitol acetal derivatives in Comparative Example 2 led to a significant increase in corrosion rate due to the increased activity of free hydroxides and sorbitol amines. In Comparative Example 3, N-hydroxyphthalimide was used instead of N,N'-dihydroxypyromellitic acid imide, which increased the activity of free hydroxides and sorbitol amines, leading to a significant increase in corrosion rate.

[0092] Figure 1 Dark-field image of an 8000 Å Cu sheet under a microscope, magnified 50 times, before immersion; Figure 2 Bright-field image of an 8000 Å Cu sheet under a microscope, magnified 50 times, before immersion; Figure 3 Dark-field image magnified 50x under a microscope of an 8000 Å Cu wafer after being soaked in the photoresist cleaning agent prepared in Example 1; Figure 4 Bright-field image under a microscope at 50x magnification of an 8000 Å Cu wafer after immersion in the photoresist cleaning agent prepared in Example 1; Figure 5 Dark-field image magnified 50x under a microscope of an 8000 Å Cu wafer soaked in the photoresist cleaning agent prepared for Comparative Example 1; Figure 6 Bright-field image of an 8000 Å Cu wafer soaked in the photoresist cleaning agent prepared for Comparative Example 1, magnified 50 times under a microscope.

[0093] from Figure 1-4 The comparison shows that the morphology of the Cu sheet after immersion in Example 1 is not significantly different from that before immersion, indicating that the Cu surface has not been corroded. Figure 1 , Figure 2 , Figure 5 and Figure 6 The comparison shows that Figure 5 Corrosion bright spots appear in the dark field. Figure 6 The dimming of the bright field indicates that Cu has undergone severe corrosion.

[0094] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A photoresist cleaning agent for cleaning Micro-LED chips, characterized in that, Based on parts by weight, it includes the following components: 5-15 parts of quaternary ammonium base; 20-50 parts of alcohol amine; 45-75 parts of polar solvent; 0.01-0.1 parts of N,N'-dihydroxypyromellitic acid imine; 0.1-1 part of sorbitol acetal derivative.

2. The photoresist cleaning agent for Micro-LED chip cleaning according to claim 1, characterized in that, The quaternary ammonium base is selected from one or more of tetramethylammonium hydroxide, choline, methyltriethylammonium hydroxide, trimethylethylammonium hydroxide, tetrapropylammonium hydroxide, and tetraethylammonium hydroxide.

3. The photoresist cleaning agent for Micro-LED chip cleaning according to claim 1, characterized in that, The alkanolamine is selected from one or more of monoethanolamine, isopropanolamine, diethanolamine, triethanolamine, N-methyldiethanolamine, methylmonoethanolamine, 2-amino-2-methyl-1-propanol, 2-diethylaminoethanol, and hydroxyethylethylenediamine.

4. The photoresist cleaning agent for Micro-LED chip cleaning according to claim 1, characterized in that, The mass ratio of the alcohol amine to the quaternary ammonium base is 2-6:

1.

5. The photoresist cleaning agent for Micro-LED chip cleaning according to claim 1, characterized in that, The polar solvent is selected from one or more of diethylene glycol monobutyl ether, propylene glycol monobutyl ether, propylene glycol monomethyl ether, N,N-dimethylformamide, dimethyl sulfoxide, N-ethylpyrrolidone, 1,3-dimethyl-2-imidazolinone, N,N-dimethylpropionamide, N-methylcaprolactam, N-butylpyrrolidone, and N,N-dimethylisobutyramide.

6. The photoresist cleaning agent for Micro-LED chip cleaning according to claim 1, characterized in that, The sorbitol acetal derivative is selected from 1,3:2,4-dibenzylidene-D-sorbitol and / or 1,3:2,4-di(3,4-dimethylbenzylidene)-D-sorbitol.

7. The photoresist cleaning agent for Micro-LED chip cleaning according to claim 1, characterized in that, The mass ratio of the sorbitol acetal derivative to N,N'-dihydroxypyromellitic acid imine is 8-12:

1.

8. A method for preparing the photoresist cleaning agent for Micro-LED chip cleaning according to any one of claims 1-7, characterized in that, Includes the following steps: N,N'-dihydroxypyromellitic acid imine is added to a polar solvent and stirred until completely dissolved. Then, a quaternary ammonium base and an alkanolamine are added and stirred again until completely dissolved. Finally, a sorbitol acetal derivative is added and heated at 55-65°C with stirring until completely dissolved to obtain the photoresist cleaning agent for Micro-LED chip cleaning.

9. The application of the photoresist cleaning agent for Micro-LED chip cleaning as described in any one of claims 1-7 in the field of Micro-LED chip cleaning.

10. The application according to claim 9, characterized in that, The method for cleaning Micro-LED chips using photoresist cleaner is as follows: S1. Immerse the Micro-LED chip in a photoresist cleaning solution for Micro-LED chip cleaning at 60-90℃ to obtain the immersed chip; S2. Rinse the soaked chip to complete the cleaning of the Micro-LED chip.

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