A photoresist stripper composition containing a gemini quaternary phosphonium salt, and a preparation method and application thereof

Abstract

The application discloses a photoresist stripper composition containing a gemini quaternary phosphonium salt and a preparation method and application thereof. The composition comprises, in parts by weight, 1-5 parts of the gemini quaternary phosphonium salt, 65-75 parts of an organic solvent, 10-15 parts of an organic alcohol amine, 1.5-5 parts of an inhibitor, 0.1-0.5 parts of an antifoaming agent and 1-2 parts of a wetting agent. The stripper has the advantages of fast stripping speed, strong stripping capacity, maintained stripping performance at a lower temperature, low corrosion to various substrates such as metals, silicon and silicon oxide, good water solubility, easy cleaning and good application prospect in the fields of semiconductor wafer cleaning and the like.

Description

Technical Field

[0001] This invention relates to the field of semiconductor manufacturing technology, specifically to a photoresist stripper composition containing gemini quaternary phosphonium salt, its preparation method, and its application. Background Technology

[0002] In semiconductor device manufacturing, photoresist, as a key material for pattern transfer, needs to be completely removed after fulfilling its function. The quality of the photoresist removal process directly affects the performance and yield of semiconductor devices. Incomplete photoresist removal leads to residues, which can cause short circuits, leakage current, or other reliability issues. Currently, commonly used photoresist removal technologies mainly include wet chemical removal and dry plasma removal. Wet chemical removal is widely used due to its simplicity and low cost. However, with the continuous shrinking of semiconductor technology nodes and the introduction of new materials, traditional photoresist removers face many challenges: (1) Corrosion of metal materials: Copper, aluminum and other metal interconnect materials are widely used in modern semiconductor devices. The strong alkaline components in traditional adhesive removers can easily corrode these metals, leading to a decline in device performance.

[0003] (2) Removal efficiency and thoroughness issues: Especially for photoresists that have undergone ion implantation or high-temperature treatment, their chemical structure changes, making them more difficult to remove. Traditional photoresist removers are often ineffective in removing this type of hardened photoresist, easily leaving residues on the wafer surface.

[0004] (3) Compatibility with new materials: With the development of semiconductor technology, a variety of new materials such as low-k dielectric materials and ultra-thin barrier layers have been introduced into the devices. These materials are highly sensitive to chemical reagents and are easily damaged by traditional adhesive removers.

[0005] (4) Environmental and safety issues: Some traditional adhesive removers contain environmentally unfriendly ingredients, such as hydroxylamine, which pose safety risks and have high processing costs.

[0006] (5) Photoresist removal at wafer edges: Photoresist tends to accumulate at wafer edges and is difficult to remove evenly. Traditional photoresist removers often perform poorly in this area. In recent years, some new technologies have been developed to solve these problems.

[0007] CN201911319064 discloses a cleaning solution containing quaternary ammonium hydroxide, alkanolamine, water, defoamer and organic solvent, which can efficiently remove photoresist residues, has virtually no corrosion to metals such as copper and aluminum, and hardly causes foaming.

[0008] CN202011486530 discloses a photoresist stripper containing quaternary ammonium hydroxide, an organic solvent, an organic alcohol amine, an organic alcohol, and a metal protectant. This stripper maintains its stripping performance at relatively low temperatures and reduces corrosion to various substrates. However, these existing strippers still suffer from low removal efficiency or insufficient compatibility with specific materials when targeting certain types of cured photoresists, especially those used in advanced manufacturing processes. Therefore, there is an urgent need in the art to develop a photoresist stripper composition that can efficiently remove various types of photoresists, provide comprehensive protection to various substrate materials, and is also environmentally friendly and has a wide operating temperature range.

[0009] This invention addresses the shortcomings of existing photoresist strippers, such as low removal efficiency, insufficient compatibility with specific materials, and high corrosion rates on metals. It provides a photoresist stripping composition that efficiently removes various types of photoresist, especially hardened photoresist, while exhibiting low corrosivity to various metals and non-metals commonly used in semiconductor manufacturing. Furthermore, the preparation process of this photoresist stripping composition is simple, easy to industrialize, and suitable for applications in semiconductor manufacturing processes, particularly for removing photoresist and photoresist residues from wafer surfaces. Summary of the Invention

[0010] To achieve the above technical objectives, the present invention provides a photoresist stripper composition containing Gemini quaternary phosphonium salt, comprising the following components in parts by weight: 1-5 parts of Gemini quaternary phosphonium salt, 65-75 parts of organic solvent, 10-15 parts of organic alcohol amine, 1.5-5 parts of corrosion inhibitor, 0.1-0.5 parts of defoamer, and 1-2 parts of wetting agent.

[0011] Furthermore, the structure of the gemini quaternary phosphonium salt is as follows: .

[0012] Further, the organic solvent is one of N-methylpyrrolidone, γ-butyrolactone, dimethyl sulfoxide, propylene carbonate, sulfolane, N,N-dimethylacetamide, or N-acetylmorpholine.

[0013] Furthermore, the organic solvent is N-methylpyrrolidone or γ-butyrolactone.

[0014] Furthermore, the organic alcohol amine is one of monoethanolamine, diethanolamine, triethanolamine, N-methylethanolamine, dimethylethanolamine, N-(2-hydroxyethyl)piperazine, or tri(2-hydroxyethyl)amine.

[0015] Furthermore, the organic alcohol amine is one of monoethanolamine, diethanolamine, or triethanolamine.

[0016] Further, the corrosion inhibitor is one of benzotriazole, methylbenzotriazole, mercaptobenzothiazole, 1,2,4-triazole, benzimidazole, 2-mercaptobenzothiazole or 2-mercaptobenzoimidazol.

[0017] Furthermore, the corrosion inhibitor is one of benzotriazole, methylbenzotriazole, or mercaptobenzothiazole.

[0018] Furthermore, the defoamer is one of polysiloxane defoamers, polyether-modified acrylates, or fluorinated polyethers.

[0019] Furthermore, the defoamer is a polysiloxane-based defoamer.

[0020] Furthermore, the wetting agent is one of a fluorocarbon surfactant, a siloxane surfactant, or an acetylene glycol surfactant, preferably a fluorocarbon surfactant.

[0021] Furthermore, the wetting agent is one of perfluoropolyether alcohol, short-chain fluoropolymer, fluoroalkyl sulfonate, or fluoroalkyl carboxylate.

[0022] The present invention also provides a method for preparing the photoresist stripper composition containing the gemini quaternary phosphonium salt, comprising the following steps: (1) Add the organic solvent to the reaction vessel and control the temperature at 20-35℃; (2) Slowly add the gemini quaternary phosphonium salt to the reactor and stir at 100-200 rpm for 1-2 hours until completely dissolved; (3) Add the organic alcohol amine and corrosion inhibitor in sequence, and stir at 100-200 rpm for 15-30 minutes after each component is added; (4) Add the defoamer and wetting agent, and stir continuously at 100-200 rpm for 15-30 minutes; (5) The obtained mixture was filtered through a 0.1 μm filter to remove insoluble matter, and a clear and transparent photoresist remover composition was obtained.

[0023] The photoresist stripper composition containing gemini quaternary phosphonium salt provided by this invention is used in semiconductor wafer cleaning processes.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) High efficiency in removing photoresist: The photoresist composition of the present invention can quickly and effectively remove various types of photoresist, including hardened photoresist that has been ion implanted or treated at high temperature. It has a fast removal speed, strong removal ability, and can maintain excellent removal performance at low temperatures.

[0025] (2) Wide material compatibility: The degumming agent composition of the present invention has low corrosivity to various substrates such as metals such as copper and aluminum, silicon, silicon dioxide, and passivation layers, and can meet the stringent material compatibility requirements of advanced semiconductor manufacturing.

[0026] (3) Wide operating window: The degumming agent composition of the present invention can maintain good degumming performance in a temperature range of 30-90℃, providing flexible space for process optimization.

[0027] (4) Environmentally friendly: The degumming agent composition of the present invention does not contain high-risk substances such as hydroxylamine, produces less foam during use, is easy to clean, has good water solubility, and reduces the burden of wastewater treatment.

[0028] This invention provides a semiconductor compound photoresist stripper with advantages such as economy, environmental friendliness, high efficiency, long lifespan, and good storage resistance. Its core component, Gemini-P2Rx, transforms toxic phosphine tail gas from a pollutant into an economically valuable product, not only reducing pollution and being environmentally friendly but also providing highly efficient photoresist stripping performance. Studies have shown that the quaternary phosphonium ion at the center of the gemini quaternary phosphonium salt has a higher charge number than that of the quaternary ammonium salt ion. Therefore, the hydroxide of the quaternary phosphonium salt is more alkaline than that of alkyl quaternary ammonium salts, effectively decomposing the polymers in the photoresist while exhibiting less corrosivity to metals compared to inorganic alkalis. This photoresist stripper shows excellent application prospects and potential for large-scale industrial application in the field of photoresist cleaning. Attached Figure Description

[0029] Figure 1 This is a cross-sectional electron microscope image of the adhesive layer and the metal coating. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. The specific embodiments described herein are for illustrative purposes only and are not intended to limit the invention.

[0031] The present invention will be further described in detail below through specific embodiments, but the scope of protection of the present invention is not limited to these embodiments.

[0032] A method for preparing a semiconductor photoresist stripper containing a gemini quaternary phosphonium salt includes the following steps: (1) Add organic solvent to the reaction vessel and control the temperature at 20-35℃; (2) Slowly add the geminal quaternary phosphonium salt to the reactor and stir at 100-200 rpm for 1-2 hours until completely dissolved; (3) Add the organic alcohol amine and corrosion inhibitor in sequence. After each component is added, stir at 100-200 rpm for 15-30 minutes to ensure uniform dispersion; (4) Finally, add the defoamer and wetting agent, and stir continuously at 100-200 rpm for 15-30 minutes; (5) The insoluble matter was removed by filtration with a 0.1 μm filter element to obtain a clear and transparent photoresist desizing agent composition containing Gemini quaternary phosphonium salt.

[0033] The organic solvent is one of N-methylpyrrolidone, γ-butyrolactone, dimethyl sulfoxide, propylene carbonate, sulfolane, N,N-dimethylacetamide, or N-acetylmorpholine, preferably N-methylpyrrolidone or γ-butyrolactone. N-methylpyrrolidone (NMP) has high polarity and strong dissolving ability, and can effectively dissolve components such as quaternary phosphonium salts and organic alcohol amines, making it a good photoresist stripping carrier solvent.

[0034] The structure of the geminal quaternary phosphonium salt is as follows: The 2-cyanoethyl group in Gemini-P2Rx is a strong electron-withdrawing group, which strongly pulls away the electron cloud surrounding the phosphorus atom, making P... + The increased positive charge enhances its ability to carry OH groups. - The nucleophilicity of the attacking ester / amide bonds, coupled with the fact that 2-cyanoethyl is a strongly polar group, allows for rapid penetration into adhesive layers (polar polymers such as photoresists, polyimide (PI), and epoxy resins). Under alkaline conditions (in a desizing environment), cyanoethyl is relatively stable. The phosphorus atom of the central quaternary phosphonium ion in Gemini-P2Rx is larger than the nitrogen atom in the quaternary ammonium salt ion, and one Gemini-P2Rx carries two OH groups. - The hydrophobic carbon chain carried by Gemini-P2Rx assists the quaternary phosphonium cation to permeate into the hydrophobic polymer, and the strong base OH carried by Gemini-P2Rx... - By severing ester / amide bonds in photoresists or resins and working with solvent molecules to penetrate and expand the polymer chains, it exhibits stronger basicity and nucleophilicity, higher thermal stability, and better alicyclic polymer degradation ability compared to traditional tetramethylammonium hydroxide (TMAH), choline-based or quaternary ammonium salt desizing agents. It can attack ester or amide bonds in photoresists, promoting their hydrolysis / degradation, and can be used for difficult-to-remove cross-linked photoresists. At the same time, the positively charged phosphorus ions help penetrate into the residual adhesive layer.

[0035] The organic alcohol amine is one of monoethanolamine, diethanolamine, triethanolamine, N-methylethanolamine, dimethylethanolamine, N-(2-hydroxyethyl)piperazine, or tri(2-hydroxyethyl)amine, preferably one of monoethanolamine, diethanolamine, or triethanolamine. Monoethanolamine (MEA) provides an alkaline environment to enhance degumming performance, assists quaternary phosphonium salts in catalyzing the saponification reaction of ester polymers, promotes the hydrolysis of ester bonds or acid-sensitive groups in photoresist, and also has certain complexing ability and wettability.

[0036] The corrosion inhibitor is one of benzotriazole, methylbenzotriazole, mercaptobenzothiazole, 1,2,4-triazole, benzimidazole, 2-mercaptobenzothiazole, or 2-mercaptobenzothiazole, preferably one of benzotriazole, methylbenzotriazole, or mercaptobenzothiazole. Benzotriazole (BTA) forms a chelate film with metal surfaces such as copper, preventing alkaline components from corroding metal circuits (such as Cu interconnect layers) and protecting the device structure.

[0037] The defoamer is a polysiloxane defoamer, a polyether-modified acrylate, or a fluorinated polyether, preferably a polysiloxane defoamer. The polysiloxane defoamer is used to suppress foam generated during stirring or spraying, to ensure process stability, and to prevent bubbles from affecting the uniformity of cleaning.

[0038] The wetting agent is one of fluorocarbon surfactants, siloxane surfactants, or acetylene glycol surfactants, preferably fluorocarbon surfactants. Fluorocarbon wetting agents significantly reduce the surface tension of the liquid, improve the wetting and spreading ability of the solution on the wafer surface, especially the trench structure, and enhance the degumming efficiency.

[0039] Examples 1-3 disclose the components and weight proportions of various semiconductor photoresist strippers, as shown in Table 1.

[0040] Table 1. Components and weight ratios of photoresist stripper in Examples 1-3, with the remainder being water.

[0041] Comparative Example 1 was achieved by replacing the Gemini-P2Rx quaternary phosphonium salt with an equivalent amount of quaternary ammonium hydroxide salt, with other conditions being the same as in Example 1.

[0042] Comparative Example 2 used a commercially available degumming agent.

[0043] Performance Testing and Explanation To verify the actual photoresist removal effect of the photoresist stripper composition of the present invention, the following technical methods were used for testing: a 0.3 μm AlSl alloy metal layer was deposited on a silicon wafer substrate using physical vapor deposition; then a 1 μm thick photoresist film was coated using a coating equipment, and the film was immersed in Examples 1-3 and Comparative Examples 1 and 2 at 80 °C for 15 min respectively. After immersion, the film was rinsed with pure water for 10 min, and finally dried by nitrogen purging.

[0044] (1) Resin removal rate test: The resist removal rate is calculated by measuring the average thickness of the residual photoresist.

[0045] (2) Metal corrosion test: the corrosion rate is calculated by measuring the average thickness of the metal layer.

[0046] (3) Residue test: Use a scanning electron microscope to observe the surface of the wafer after the adhesive is removed to check for any residue.

[0047] The specific test results are shown in Table 2: Examples 1-3 showed low corrosion rates on the metal substrate, where the composition was the same.

[0048] Table 2 Test results of Examples 1-3 and Comparative Examples 1-2 To further compare the photoresist stripping ability and metal corrosion resistance of Example 1 and Comparative Example 1, the present invention employs the following technical method: A 0.3 μm AlSi alloy metal layer is deposited on a silicon wafer substrate using physical vapor deposition; then, a 1 μm thick photoresist film is coated using a coating device. The substrate is then immersed in the solutions of Example 1 and Comparative Example 1 at 70°C, 80°C, and 90°C for 15 min and 30 min respectively, followed by rinsing with pure water for 10 min, and then purging and drying with nitrogen. The residual photoresist and corrosion of the metal layer on the silicon wafer surface are observed using a microscope. The results are as follows: Figure 1 As shown in Table 3.

[0049] Table 3 The above verification experiments show that Example 1 has strong photoresist stripping ability under different temperatures and times, and does not cause corrosion to the metal substrate, which can meet the needs of photoresist stripping solution in the semiconductor industry.

[0050] In summary, this invention innovatively introduces a quaternary osmotic salt active system and a corrosion inhibitor, combined with ultra-low surface tension wetting technology, to achieve synergistic optimization of multiple performance objectives and resolve the long-standing contradiction between 'thoroughness of resist removal' and 'device safety' in advanced processes.

[0051] Although the above embodiments have described the present invention and its implementation in detail, it should be noted that for those skilled in the art, any changes, modifications, substitutions, combinations, simplifications, etc., made to the corresponding conditions without departing from the technical principles of the present invention should be considered as equivalent substitutions, and these improvements should also be considered within the scope of protection of the present invention.

Claims

1. A photoresist stripper composition containing a gemini quaternary phosphonium salt, characterized in that, By weight, it comprises the following components: 1-5 parts quaternary phosphonium salt, 65-75 parts organic solvent, 10-15 parts organic alcohol amine, 1.5-5 parts corrosion inhibitor, 0.1-0.5 parts defoamer, and 1-2 parts wetting agent; The structure of the geminal quaternary phosphonium salt is as follows: 。 2. The photoresist stripper composition according to claim 1, characterized in that, The organic solvent is one of N-methylpyrrolidone, γ-butyrolactone, dimethyl sulfoxide, propylene carbonate, sulfolane, N,N-dimethylacetamide, or N-acetylmorpholine, preferably N-methylpyrrolidone or γ-butyrolactone.

3. The photoresist stripper composition according to claim 1, characterized in that, The organic alcohol amine is one of monoethanolamine, diethanolamine, triethanolamine, N-methylethanolamine, dimethylethanolamine, N-(2-hydroxyethyl)piperazine, or tri(2-hydroxyethyl)amine, preferably one of monoethanolamine, diethanolamine, or triethanolamine.

4. The photoresist stripper composition according to claim 1, characterized in that, The corrosion inhibitor is one of benzotriazole, methylbenzotriazole, mercaptobenzothiazole, 1,2,4-triazole, benzimidazole, 2-mercaptobenzothiazole or 2-mercaptobenzothiazole, preferably one of benzotriazole, methylbenzotriazole or mercaptobenzothiazole.

5. The photoresist stripper composition according to claim 1, characterized in that, The defoamer is a polysiloxane defoamer, a polyether-modified acrylate, or a fluorinated polyether, preferably a polysiloxane defoamer.

6. The photoresist stripper composition according to claim 1, characterized in that, The wetting agent is one of fluorocarbon surfactants, siloxane surfactants, or acetylene glycol surfactants, preferably fluorocarbon surfactants.

7. A method for preparing a photoresist stripper composition according to any one of claims 1-6, characterized in that, Includes the following steps: (1) Add the organic solvent to the reaction vessel and control the temperature at 20-35℃; (2) Slowly add the geminal quaternary phosphonium salt to the reactor and stir at 100-200 rpm for 1-2 hours until completely dissolved; (3) Add the organic alcohol amine and corrosion inhibitor in sequence, and stir at 100-200 rpm for 15-30 minutes after each component is added; (4) Add the defoamer and wetting agent, and stir continuously at 100-200 rpm for 15-30 minutes; (5) The obtained mixture was filtered through a 0.1 μm filter to remove insoluble matter, and a clear and transparent photoresist stripper composition was obtained.

8. The photoresist stripper according to any one of claims 1-7, characterized in that, Applications in semiconductor wafer cleaning processes.

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