A stripping solution for removing a copper layer negative photoresist, a preparation method and application thereof

Abstract

The application provides a stripping solution for removing a copper layer negative photoresist, a preparation method and application thereof. The stripping solution comprises a polar solvent, a dissolving promoter, a mutual solvent and a corrosion inhibitor. The corrosion inhibitor comprises carboxybenzotriazole and / or mercaptobenzothiazole. The application uses carboxybenzotriazole and / or mercaptobenzothiazole as the corrosion inhibitor. In the dissolving process, the corrosion inhibitor can form a chelate with copper, effectively controls the corrosion rate of the stripping solution, and avoids the copper corrosion.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor manufacturing technology, specifically relating to a stripping solution for removing negative photoresist from copper layers, its preparation method, and its application. Background Technology

[0002] With the rapid development of the electronics industry and the manufacturing of large-scale integrated circuits, photoresist is increasingly widely used. Devices often undergo processes such as coating, development, electroplating, and resist removal. As the packaging industry develops, titanium-copper substrates are sputtered onto silicon substrates, and photoresist is coated onto the copper layer. The photoresist primarily used is acrylic resin, which is a negative photoresist. Its main formulation consists of acrylic resin, solvent, crosslinking agent, and initiator. Because a thickness of 110μm is required, it involves two coatings and two baking cycles. Due to the need for copper, nickel, and tin-silver electroplating, photoresist manufacturers typically increase the crosslinking degree of the photoresist to resist the erosion of the electroplating solution. After electroplating, the residual etched photoresist on the upper layer also needs to be removed using a stripping solution. However, because it needs to withstand immersion in the electroplating solution, to enhance the adhesion between the photoresist and the substrate, the baking temperature needs to be increased to mitigate the electroplating characteristics. However, excessively high baking temperatures can negatively impact resist removal. As the baking process and formulation increase the crosslinking density of the photoresist, higher requirements are also placed on the stripping solution for the photoresist. At the same time, the corrosion of the substrate copper by the stripping solution also needs to be considered.

[0003] CN103605269A discloses a novel photoresist removal solution, comprising pentaerythritol, potassium hydroxide, an organic amine, a corrosion inhibitor, and a solvent. The organic amine is selected from at least one compound grouped from the group consisting of monoethanolamine, isopropanolamine, aminoethoxyethanol, n-methylethanolamine, dimethylethanolamine, diethylethanolamine, 2-aminoethylaminoethanol, aminoethylpiperazine, aminopropylpiperazine, 1-(2-hydroxyethyl)piperazine, 1-amino-4-methylpiperazine, 2-methylpiperazine, 1-methylpiperazine, 1-benzylpiperazine, 2-phenylpiperazine, 1-aminoethylpiperidine, 1-aminopiperidine, and 1-aminomethylpiperidine.

[0004] CN1739064A discloses a composition and method for semiconductor processing. In one embodiment, a wet cleaning composition for removing photoresist is provided. This composition comprises a strong base, an oxidizing agent, and a polar solvent. In another embodiment, a method for removing photoresist is provided. This method includes the steps of: coating a wet cleaning composition comprising about 0.1-about 30 wt% of a strong base, about 1-about 30 wt% of an oxidizing agent, and about 20-about 95 wt% of a polar solvent; and removing the photoresist.

[0005] CN104614954A discloses a photoresist stripping solution composition, primarily used for removing unexposed photoresist during semiconductor device manufacturing. The photoresist stripping solution comprises 20-70% by mass of a polar solvent, 5-50% by mass of an organic amine compound, 0.01-5% by mass of a surfactant, 0.01-5% by mass of a corrosion inhibitor, and 10-60% by mass of deionized water. During this process, unexposed photoresist is removed from semiconductor devices at low temperatures, with minimal corrosion to the semiconductor device metals and no swelling of the PI substrate.

[0006] Because the copper substrate is sputtered and is less than 1μm thick, the electroplated copper pillars are particularly susceptible to corrosion by alkaline stripping solutions. Commercially available stripping solutions typically contain organic and inorganic alkali solutions, such as aqueous solutions of NaOH and KOH, or organic systems of ethanolamine and diethanolamine. However, the strong alkalinity of inorganic alkalis can severely corrode the metallic copper layer, making it difficult to control. While organic amines are less alkaline, their alkalinity increases upon contact with water during the washing process, also causing corrosion to copper. Furthermore, amine systems generally have rapid dissolution characteristics for phenolic resins but poor dissolution characteristics for acrylic resins, resulting in weak adhesive removal capabilities and requiring high-temperature, long-duration processes, which is detrimental to improving the efficiency of the adhesive removal stage.

[0007] Therefore, developing a photoresist stripping solution that does not contain organic or inorganic alkalis, has a low corrosion rate on copper layers, and minimizes copper layer corrosion is a key research focus in this field. Summary of the Invention

[0008] To address the shortcomings of existing technologies, the present invention aims to provide a stripping solution for removing negative photoresist from copper layers, its preparation method, and its application, which can effectively remove photoresist while exhibiting a low corrosion rate and minimizing corrosion of the copper layer.

[0009] To achieve this objective, the present invention adopts the following technical solution:

[0010] In a first aspect, the present invention provides a stripping solution for removing negative photoresist from a copper layer, characterized in that the stripping solution comprises a polar solvent, a co-solvent, a mutual solvent, and a corrosion inhibitor.

[0011] The corrosion inhibitors include carboxybenzotriazole and / or mercaptobenzothiazole.

[0012] This invention uses 5-carboxybenzotriazole and / or 2-mercaptobenzothiazole (MBT) as corrosion inhibitors. During the dissolution process, the corrosion inhibitors can form chelates with copper, effectively controlling the corrosion rate of the stripping solution and avoiding copper corrosion.

[0013] Preferably, the stripping solution does not contain organic or inorganic bases.

[0014] Preferably, the corrosion inhibitor is a combination of carboxybenzotriazole and mercaptobenzothiazole.

[0015] Preferably, the mass ratio of carboxybenzotriazole to mercaptobenzothiazole is (0.5-1.5):1, for example, it can be 0.6:1, 0.8:1, 1:1, 1.2:1, 1.4:1, etc.

[0016] Preferably, the stripping solution comprises, by weight, 30-75 parts of a polar solvent (e.g., 32, 34, 36, 38, 40, 42, 44, 46, 48, 50, 52, 54, 56, 58, 60, 62, 64, 66, 68, 70, 72, 74, etc.), 10-25 parts of a co-solvent (e.g., 12, 14, 16, 18, 20, 22, 24, etc.), and 2-10 parts of a miscible solvent (e.g., 2.5...). Quantities of 1 part, 3 parts, 3.5 parts, 4 parts, 4.5 parts, 5 parts, 5.5 parts, 6 parts, 6.5 parts, 7 parts, 7.5 parts, 8 parts, 8.5 parts, 9 parts, 9.5 parts, etc.) and corrosion inhibitor 0.05-2 parts (e.g., 0.06 parts, 0.08 parts, 0.1 parts, 0.2 parts, 0.3 parts, 0.4 parts, 0.5 parts, 0.6 parts, 0.7 parts, 0.8 parts, 0.9 parts, 1 part, 1.1 parts, 1.2 parts, 1.3 parts, 1.4 parts, 1.5 parts, 1.6 parts, 1.7 parts, 1.8 parts, 1.9 parts, etc.).

[0017] Preferably, the polar solvent includes any one or a combination of at least two of diethylene glycol diethyl ether, propylene glycol methyl ether acetate, hexamethylphosphoramide, or 3-methoxybutyl acetate.

[0018] Preferably, the co-solvent comprises pentaerythritol and / or pentaerythritol triacrylate.

[0019] Preferably, the mutual solvents include diethylene glycol and / or glycerol.

[0020] All other specific point values ​​within the above numerical ranges can be selected, and will not be elaborated on here.

[0021] This invention abandons the conventional formulation of organic solvents and organic bases commonly used in existing technologies, and instead employs similar and compatible raw materials. Acrylic resins generally use propylene glycol methyl ether acetate and diethylene glycol diethyl ether as solvents, with pentaerythritol-based crosslinking agents as the main structure. Therefore, this invention uses similar solvents and crosslinking agents as the main formulation, which can dissolve photoresist under medium-temperature conditions. To improve the compatibility between pentaerythritol and the solvent, and to improve the compatibility with the water washing process, this invention adds an alcohol-based mutual solvent to improve the solubility characteristics of the solvent, co-solvent, and photoresist, thereby enhancing the water washing capability.

[0022] In a second aspect, the present invention provides a method for preparing a stripping solution for removing negative photoresist from a copper layer as described in the first aspect, the method comprising: mixing a polar solvent, a co-solvent, a mutual solvent and a corrosion inhibitor uniformly to obtain the solution.

[0023] Thirdly, the present invention provides an application of the stripping solution for removing negative photoresist from copper layers as described in the first aspect in semiconductor manufacturing.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] This invention uses carboxybenzotriazole and / or mercaptobenzothiazole as corrosion inhibitors. During the dissolution process, the corrosion inhibitors can form chelates with copper, effectively controlling the corrosion rate of the stripping solution and preventing copper corrosion. Furthermore, to improve the compatibility of the co-solvent and the solvent, and to enhance the compatibility of the washing process, this invention adds an alcohol-based mutual solvent to improve the solubility characteristics of the solvent, co-solvent, and photoresist, thereby improving the washing capability. Attached Figure Description

[0026] Figure 1 This is a diagram showing the degumming effect of the stripping solution in Example 1;

[0027] Figure 2 This is a diagram showing the degumming effect of the stripping solution in Comparative Example 1. Detailed Implementation

[0028] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0029] The terms “comprising,” “including,” “having,” “containing,” or any other variations thereof, as used herein, are intended to cover non-exclusive inclusion. For example, a composition, step, method, article, or apparatus that includes the listed elements is not limited to those elements and may also include other elements not expressly listed or elements inherent to such composition, step, method, article, or apparatus.

[0030] "Optional" or "any one" means that the matter or event described thereafter may or may not occur, and the description includes both the possibility that the event will occur and the possibility that the event will not occur.

[0031] The indefinite articles “a” and “an” preceding an element or component of this invention do not impose any limitation on the quantity (i.e., number of times) of the element or component. Therefore, “an” or “a” should be interpreted as including one or at least one, and the singular form of an element or component also includes the plural form, unless the quantity clearly refers only to the singular form.

[0032] The terms "one embodiment," "some embodiments," "exemplary," "specific example," or "some examples," etc., used in this invention refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the invention. In this document, the illustrative expressions of the above terms are not necessarily directed at the same embodiment or example.

[0033] The reagents or instruments used in the following examples are from the following sources:

[0034] Hexamethylphosphoramide: Aladdin, industrial grade;

[0035] Diethylene glycol diethyl ether: Anhui Lixing New Materials Co., Ltd., industrial grade;

[0036] Pentaerythritol: Merck Materials Science, Industrial Grade;

[0037] Pentaerythritol triacrylate: Wuhan Kemic Biopharmaceutical, industrial grade;

[0038] Diethylene glycol: Ruisheng Chemical Technology, industrial grade;

[0039] Glycerol: Jiujiu Chemical, industrial grade;

[0040] 5-Carboxybenzotriazole: Jiangsu Bosite Chemical Co., Ltd., content >98%;

[0041] 2-Mercaptobenzothiazole: MBT: Shandong Shouhua Chemical, content >98%.

[0042] Example 1

[0043] This embodiment provides a stripping solution for removing negative photoresist from copper layers. The raw materials of the stripping solution include the following components: 70 parts hexamethylphosphoramide, 20 parts pentaerythritol, 9 parts diethylene glycol, 0.5 parts 5-carboxybenzotriazole, and 0.3 parts MBT.

[0044] Preparation method: Mix the aforementioned components according to the formula to obtain the stripping solution.

[0045] Example 2

[0046] This embodiment provides a stripping solution for removing negative photoresist from copper layers. The raw materials of the stripping solution include the following components: 75 parts of propylene glycol methyl ether acetate, 15 parts of pentaerythritol, 8 parts of glycerol, 0.1 parts of 5-carboxybenzotriazole, and 0.1 parts of MBT.

[0047] Preparation method: Mix the aforementioned components according to the formula to obtain the stripping solution.

[0048] Example 3

[0049] This embodiment provides a stripping solution for removing negative photoresist from copper layers. The raw materials of the stripping solution include the following components: 66 parts of diethylene glycol diethyl ether, 25 parts of pentaerythritol triacrylate, 8 parts of diethylene glycol, 0.15 parts of 5-carboxybenzotriazole, and 0.1 parts of MBT.

[0050] Preparation method: Mix the aforementioned components according to the formula to obtain the stripping solution.

[0051] Example 4

[0052] This embodiment provides a stripping solution for removing negative photoresist from copper layers. The raw materials of the stripping solution include the following components: 70 parts hexamethylphosphoramide, 20 parts pentaerythritol, 9 parts diethylene glycol, and 0.8 parts 5-carboxybenzotriazole.

[0053] Preparation method: Mix the aforementioned components according to the formula to obtain the stripping solution.

[0054] Example 5

[0055] This embodiment provides a stripping solution for removing negative photoresist from copper layers. The raw materials of the stripping solution include the following components: 70 parts hexamethylphosphoramide, 20 parts pentaerythritol, 9 parts diethylene glycol, and 0.8 parts MBT.

[0056] Preparation method: Mix the aforementioned components according to the formula to obtain the stripping solution.

[0057] Example 6

[0058] This embodiment provides a stripping solution for removing negative photoresist from copper layers. The only difference between this solution and Example 1 is that the amount of hexamethylphosphoramide is adjusted to 80 parts. All other raw materials, dosages, and preparation methods are the same as in Example 1.

[0059] Example 7

[0060] This embodiment provides a stripping solution for removing negative photoresist from copper layers. The only difference between this solution and Example 1 is that the amount of hexamethylphosphoramide is adjusted to 25 parts. All other raw materials, dosages, and preparation methods are the same as in Example 1.

[0061] Example 8

[0062] This embodiment provides a stripping solution for removing negative photoresist from copper layers. The only difference between this solution and Example 1 is that the pentaerythritol is adjusted to 30 parts. All other raw materials, dosages, and preparation methods are the same as in Example 1.

[0063] Example 9

[0064] This embodiment provides a stripping solution for removing negative photoresist from copper layers. The only difference between this solution and Example 1 is that the pentaerythritol is adjusted to 8 parts. All other raw materials, dosages, and preparation methods are the same as in Example 1.

[0065] Example 10

[0066] This embodiment provides a stripping solution for removing negative photoresist from copper layers. The only difference between this solution and Example 1 is that the diethylene glycol is adjusted to 12 parts. All other raw materials, dosages, and preparation methods are the same as in Example 1.

[0067] Example 11

[0068] This embodiment provides a stripping solution for removing negative photoresist from copper layers. The only difference between this solution and Example 1 is that the diethylene glycol is adjusted to 1 part. All other raw materials, dosages, and preparation methods are the same as in Example 1.

[0069] Example 12

[0070] This embodiment provides a stripping solution for removing negative photoresist from copper layers. The only difference between this solution and Example 1 is that the amount of 5-carboxybenzotriazole is adjusted to 1.5 parts and the amount of MBT is adjusted to 0.9 parts. All other raw materials, amounts, and preparation methods are the same as in Example 1.

[0071] Example 13

[0072] This embodiment provides a stripping solution for removing negative photoresist from copper layers. The only difference between this solution and Example 1 is that the 5-carboxybenzotriazole is adjusted to 0.02 parts and the MBT is adjusted to 0.012 parts. All other raw materials, dosages, and preparation methods are the same as in Example 1.

[0073] Comparative Example 1

[0074] This comparative example provides a stripping solution for removing negative photoresist from copper layers. The only difference between this solution and Example 1 is that pentaerythritol is not added. All other raw materials, dosages, and preparation methods are the same as in Example 1.

[0075] Comparative Example 2

[0076] This comparative example provides a stripping solution for removing negative photoresist from copper layers. The only difference between this solution and Example 1 is that diethylene glycol is not added. All other raw materials, dosages, and preparation methods are the same as in Example 1.

[0077] Comparative Example 3

[0078] This comparative example provides a stripping solution for removing negative photoresist from copper layers. The only difference between this solution and Example 1 is that 5-carboxybenzotriazole and MBT are not added. All other raw materials, dosages, and preparation methods are the same as in Example 1.

[0079] Test case

[0080] Sample preparation: An acrylic negative photoresist (ATR-150N, manufactured by Jiangsu Aisen Semiconductor Materials Co., Ltd.) was coated onto an 8-inch copper substrate. A film thickness of 110 μm was obtained using a two-stage spin-coating method. After baking at 120°C for 5 minutes, the film achieved a strength of 1100 mJ / cm². 2 The sample board was obtained by energy exposure, immersion in 2.38% developer for 150 seconds, and subsequent copper electroplating.

[0081] Test method: The sample plate was immersed in the stripping solution prepared in the examples and comparative examples at 50℃ for 30 minutes, and then the surface was rinsed with deionized water. The degree of adhesive removal and the copper corrosion were then observed under a SEM microscope. The results are shown in Table 1.

[0082] The adhesive removal effect of the stripping liquid in Example 1 is as follows: Figure 1 As shown, the adhesive was removed cleanly, and the copper layer did not corrode.

[0083] The adhesive removal effect of the stripping solution in Comparative Example 1 is as follows: Figure 2 As shown, the glue was not completely removed.

[0084] Table 1

[0085]

[0086]

[0087] According to the data in the table, the best adhesive removal effect was achieved when the corrosion inhibitor was a combination of 5-carboxybenzotriazole and MBT, with no corrosion to the copper layer. When only 5-carboxybenzotriazole or MBT was used as the corrosion inhibitor, slight corrosion of the copper layer occurred. Excessive solvent usage caused slight corrosion of the copper layer, while insufficient solvent usage resulted in incomplete adhesive removal. Too much or too little co-solvent also affected the adhesive removal effect, leading to incomplete removal. Excessive use of the corrosion inhibitor resulted in incomplete adhesive removal, while insufficient use caused slight corrosion to the copper layer.

[0088] The applicant declares that the present invention is illustrated by the above embodiments, but the present invention is not limited to the above process steps, that is, it does not mean that the present invention must rely on the above process steps to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions of the raw materials used in the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A stripping solution for removing negative photoresist from copper layers, characterized in that, The stripping solution comprises, by weight, 30-75 parts of a polar solvent, 10-25 parts of a co-solvent, 2-10 parts of a mutual solvent, and 0.05-2 parts of a corrosion inhibitor; the polar solvent comprises any one or a combination of at least two of diethylene glycol diethyl ether, propylene glycol methyl ether acetate, hexamethylphosphoramide, or 3-methoxybutyl acetate; the co-solvent comprises pentaerythritol and / or pentaerythritol triacrylate; and the mutual solvent comprises diethylene glycol and / or glycerol. The corrosion inhibitors include carboxybenzotriazole and / or mercaptobenzothiazole; The stripping solution does not contain any organic or inorganic bases.

2. The stripping fluid according to claim 1, characterized in that, The corrosion inhibitor is a combination of carboxybenzotriazole and mercaptobenzothiazole.

3. The stripping fluid according to claim 1, characterized in that, The mass ratio of carboxybenzotriazole to mercaptobenzothiazole is (0.5-1.5):

1.

4. A method for preparing a stripping solution for removing negative photoresist from a copper layer as described in any one of claims 1-3, characterized in that, The preparation method includes: mixing a polar solvent, a co-solvent, a mutual solvent, and a corrosion inhibitor evenly to obtain the final product.

5. The application of a stripping solution for removing negative photoresist from copper layers as described in any one of claims 1-3 in semiconductor manufacturing.

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