A stripping solution and a method for preparing the same

Abstract

The application provides a stripping liquid and a preparation method thereof, and the stripping liquid is composed of a solubilizing agent, a metal corrosion inhibitor, a surface leveling agent and an organic solvent. The solubilizing agent can be a combination containing benzene series, which can improve the solubility of photoresist in the organic solvent and prolong the service life of the stripping liquid. The surface leveling agent is one or more of 1,3-propanediol, 2-phenyl-1,3-propanediol and 2-amino-1,3-propanediol, which is used to improve the uniformity of the stripping liquid in the stripping process and avoid uneven concave-convex phenomenon on the surface of the photoresist. The metal corrosion inhibitor can be selected from azoles or polyphenol compounds, which can inhibit the corrosion of Cu, Ag and other metals in the stripping process; the organic solvent is a combination of xylene and dichloromethane, which is mainly used for dissolving and removing the expanded and fallen photoresist. The stripping liquid provided by the application can improve the stripping rate and significantly improve the uniformity of the stripping, and can effectively protect the metal from corrosion and control the corrosion speed of Cu, Ag and other metals to be limited below 1 A / min.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor technology, specifically relating to a stripping solution and its preparation method, which is applicable to the stripping operation of ultra-fine circuit patterns during semiconductor manufacturing. Background Technology

[0002] With the increasing demand for ultra-fine circuitry in semiconductor manufacturing, the stripping effect during pattern transfer has a crucial impact on process precision. However, existing stripping solutions tend to leave dry film residue when removing the dry film from ultra-fine circuitry, failing to meet high-precision requirements. This phenomenon may affect the stability and reliability of subsequent processes, leading to a decline in process quality. Therefore, to meet the stripping requirements of ultra-fine circuitry, it is necessary to improve the formulation of existing stripping solutions. Summary of the Invention

[0003] This invention provides a stripping solution and its preparation method, which can improve the stripping rate and significantly improve the uniformity of stripping. In addition, it can effectively protect metals from corrosion and control the corrosion rate of metals such as Cu and Ag to below 1 A / min.

[0004] To achieve the above objectives, the present invention adopts the following technical solution, which, by mass percentage, contains 10-20% surface leveling agent, 2%-10% solubilizer, 0.1%-2% metal corrosion inhibitor, and the balance being organic solvent.

[0005] Furthermore, the surface leveling agent is one or more of 1,3-propanediol, 2-phenyl-1,3-propanediol, and 2-amino-1,3-propanediol.

[0006] Furthermore, the composition of the solubilizing phenolic compound and xylene at a mass ratio of 1:10-20; the phenolic compound is selected from one or more of 4-butylphenol, 4-cyclohexylphenol, and 3,4-xylenol.

[0007] The xylene is any one of o-xylene, p-xylene, and m-xylene.

[0008] In some embodiments, the solubilizer is obtained by stirring a phenolic compound with xylene at 120°C-130°C for 20-30 minutes.

[0009] Furthermore, the metal corrosion inhibitor is one or a combination of several azole and polyphenol compounds.

[0010] Furthermore, the azole compound is any one of ruliconazole, 2-aminooxazole, 5-benzyl-1H-tetrazole, and 2-ethyl-2-zoline.

[0011] Furthermore, the polyphenolic compound is either tannic acid or 4,4'-dihydroxybiphenyl.

[0012] Furthermore, the organic solvent is dichloromethane.

[0013] Furthermore, its preparation method includes the following steps:

[0014] A: Add the solubilizer and dichloromethane to a stirred tank, add the surface leveling agent, mix well, and obtain solution A.

[0015] B: Add a metal corrosion inhibitor to solution A and continue stirring to obtain solution B.

[0016] C: After letting solution B stand for a period of time, cool it to room temperature to obtain the preliminarily prepared stripping solution for filling.

[0017] Furthermore, in step A, the stirring rate is controlled at 300–500 rpm for 10–20 minutes.

[0018] Furthermore, the heating temperature in step A is maintained at 30–50°C.

[0019] Furthermore, in step B, the stirring rate is controlled at 500–800 rpm for 20–30 minutes.

[0020] Furthermore, the settling time in step C is 10 hours to 24 hours.

[0021] The present invention has the following beneficial effects:

[0022] The solubilizer in the stripping solution can improve the solubility of photoresist in organic solvents and extend the service life of the stripping solution. The surface leveling agent is used to improve the uniformity of the stripping solution during the stripping process and avoid unevenness on the photoresist surface. The metal corrosion inhibitor can inhibit the corrosion of metals such as Cu and Ag during the stripping process; the organic solvent is a combination of xylene and dichloromethane, mainly used to dissolve and remove the swollen and detached photoresist. The stripping solution provided by this invention can improve the stripping rate and significantly improve the uniformity of stripping. In addition, it can effectively protect metals from corrosion and control the corrosion rate of metals such as Cu and Ag to below 1 A / min. Detailed Implementation

[0023] The embodiments of the present invention will now be described in detail with reference to examples.

[0024] Example 1:

[0025] A stripping solution and its preparation method, comprising the following:

[0026] 8 wt% mixture of 3,4-xylenol and xylene (mass ratio 1:10), 10 wt% 1,3-propanediol, 1 wt% louriconazole, 1 wt% tannic acid, balance dichloromethane.

[0027] In this embodiment, the preparation method includes the following steps:

[0028] A: Stir 3,4-xylene and xylene at 120℃-130℃ for 30 minutes to obtain a solubilizer, then add it to a stirred tank with dichloromethane, add a surface leveling agent, mix well to obtain solution A.

[0029] B: Add a metal corrosion inhibitor to solution A and continue stirring to obtain solution B.

[0030] C: After letting solution B stand for a period of time, cool it to room temperature to obtain the preliminarily prepared stripping solution for filling.

[0031] In this embodiment, the stirring rate in step A is controlled at 400 rpm for 20 minutes.

[0032] In this embodiment, the heating temperature in step A is maintained at 50°C.

[0033] In this embodiment, the stirring rate in step B is controlled at 800 rpm for 30 minutes.

[0034] In this embodiment, the settling time in step C is 10 hours.

[0035] Example 2:

[0036] A stripping solution and its preparation method, comprising the following:

[0037] 8 wt% of a mixture of 3,4-xylenol and xylene (mass ratio 1:10), 10 wt% of 2-phenyl-1,3-propanediol, 1 wt% of 5-benzyl-1H-tetrazole, 1 wt% of tannic acid, balance dichloromethane.

[0038] In this embodiment, the preparation method is the same as in Example 1.

[0039] Example 3:

[0040] A stripping solution and its preparation method, comprising the following:

[0041] 8 wt% of a mixture of 3,4-xylenol and xylene (mass ratio 1:10), 10 wt% of 2-amino-1,3-propanediol, 1 wt% of 2-ethyl-2-zoline, 1 wt% of tannic acid, balance dichloromethane.

[0042] In this embodiment, the preparation method is the same as in Example 1.

[0043] Example 4:

[0044] A stripping solution and its preparation method, comprising the following:

[0045] 8 wt% mixture of 4-cyclohexylphenol and xylene (mass ratio 1:10), 10 wt% 2-amino-1,3-propanediol, 1 wt% 2-aminooxazole, 1 wt% tannic acid, balance dichloromethane.

[0046] In this embodiment, the preparation method is the same as in Example 1.

[0047] Example 5:

[0048] A stripping solution and its preparation method, comprising the following:

[0049] 8 wt% mixture of 4-butylphenol and xylene (mass ratio 1:10), 10 wt% 2-amino-1,3-propanediol, 1 wt% louriconazole, 1 wt% tannic acid, balance dichloromethane.

[0050] In this embodiment, the preparation method is the same as in Example 1.

[0051] Example 6:

[0052] A stripping solution and its preparation method, comprising the following:

[0053] 8 wt% mixture of 4-butylphenol and xylene (mass ratio 1:10), 10 wt% 2-amino-1,3-propanediol, 1 wt% louriconazole, 1 wt% 4,4'-dihydroxybiphenyl, balance dichloromethane.

[0054] In this embodiment, the preparation method is the same as in Example 1.

[0055] Example 7:

[0056] A stripping solution and its preparation method, comprising the following:

[0057] 8 wt% of a mixture of 4-butylphenol, 4-cyclohexylphenol and xylene (mass ratio 1:1:20), 10 wt% of 2-amino-1,3-propanediol, 1 wt% of louriconazole, 1 wt% of 4,4'-dihydroxybiphenyl, balance dichloromethane.

[0058] In this embodiment, the preparation method is the same as in Example 1.

[0059] Example 8:

[0060] A stripping solution and its preparation method, comprising the following:

[0061] 0.73% 3,4-xylenol, 7.3% xylene, 10wt% 1,3-propanediol, 1wt% ruliconazole, 1wt% tannic acid, balance dichloromethane.

[0062] In this embodiment, the preparation method includes the following steps:

[0063] A: Mix 3,4-xylenol, xylene and dichloromethane and add them to a stirred tank. Add a surface leveling agent and mix well to obtain solution A.

[0064] B: Add a metal corrosion inhibitor to solution A and continue stirring to obtain solution B.

[0065] C: After letting solution B stand for a period of time, cool it to room temperature to obtain the preliminarily prepared stripping solution for filling.

[0066] In this embodiment, the stirring rate in step A is controlled at 400 rpm for 20 minutes.

[0067] In this embodiment, the heating temperature in step A is maintained at 30~50℃.

[0068] In this embodiment, the stirring rate in step B is controlled at 800 rpm for 30 minutes.

[0069] In this embodiment, the settling time in step C is 10 hours.

[0070] Comparative Example 1:

[0071] A stripping solution and its preparation method, comprising the following:

[0072] 8 wt% xylene, 10 wt% 1,3-propanediol, 1 wt% ruliconazole, balance dichloromethane.

[0073] In this embodiment, the preparation method includes the following steps:

[0074] A: Mix xylene and dichloromethane and add them to a stirred tank. Add a surface leveling agent and mix well to obtain solution A.

[0075] B: Add a metal corrosion inhibitor to solution A and continue stirring to obtain solution B.

[0076] C: After letting solution B stand for a period of time, cool it to room temperature to obtain the preliminarily prepared stripping solution for filling.

[0077] In this embodiment, the stirring rate in step A is controlled at 400 rpm for 20 minutes.

[0078] In this embodiment, the heating temperature in step A is maintained at 30~50℃.

[0079] In this embodiment, the stirring rate in step B is controlled at 800 rpm for 30 minutes.

[0080] In this embodiment, the settling time in step C is 10 hours.

[0081] Comparative Example 2:

[0082] A stripping solution and its preparation method, comprising the following:

[0083] 8 wt% 4-Butylphenol, 10 wt% 2-Amino-1,3-propanediol, 1 wt% 4,4'-Dihydroxybiphenyl, balance dichloromethane.

[0084] In this embodiment, the preparation method includes the following steps:

[0085] A: Add 4-butylphenol and dichloromethane to a stirred tank, add a surface leveling agent, mix well, and obtain solution A.

[0086] B: Add a metal corrosion inhibitor to solution A and continue stirring to obtain solution B.

[0087] C: After letting solution B stand for a period of time, cool it to room temperature to obtain the preliminarily prepared stripping solution for filling.

[0088] In this embodiment, the stirring rate in step A is controlled at 400 rpm for 20 minutes.

[0089] In this embodiment, the heating temperature in step A is maintained at 30~50℃.

[0090] In this embodiment, the stirring rate in step B is controlled at 800 rpm for 30 minutes.

[0091] In this embodiment, the settling time in step C is 10 hours.

[0092] Comparative Example 3:

[0093] A stripping solution and its preparation method, comprising the following:

[0094] 5 wt% 4-cyclohexylphenol, 3 wt% 3,4-xylenol, 10 wt% 2-amino-1,3-propanediol, balance dichloromethane.

[0095] In this embodiment, the preparation method includes the following steps:

[0096] A: Mix 4-cyclohexylphenol, 3,4-xylenol, and dichloromethane and add them to a stirred tank. Add a surface leveling agent and mix well to obtain solution A.

[0097] B: After letting solution A stand for a period of time, cool it to room temperature to obtain the preliminarily prepared stripping solution for filling.

[0098] In this embodiment, the stirring rate in step A is controlled at 400 rpm for 20 minutes.

[0099] In this embodiment, the heating temperature in step A is maintained at 30–50°C.

[0100] In this embodiment, the settling time in step A is 10 hours.

[0101] The stripping solutions obtained in the above embodiments and comparative examples were tested to understand their corrosion data on the metal by testing the etching of a single metal layer. The etching temperature was 50°C and the time was 10 minutes.

[0102] Specifically, the stripping solution was prepared in a beaker according to its composition. After preparation, 50g of the solution was weighed and placed in a 50°C constant temperature water bath. After the temperature of the stripping solution reached 50°C and stabilized for a period of time, copper and silver metal sheets were cut into the same size using a glass cutter, rinsed with ultrapure water, and purged with nitrogen. The film thickness of the copper and silver sheets before etching was measured using a four-probe thickness gauge. Then, the copper and silver sheets were fixed with a rack and suspended and immersed in the 50°C etching solution. After etching for 10 minutes, the copper and silver sheets were removed, rinsed with ultrapure water, purged with nitrogen, and the film thickness of the copper and silver sheets after etching was measured using a four-probe thickness gauge. The corrosion rate of the stripping solution on the metal was obtained by measuring the change in film thickness before and after etching.

[0103] After obtaining the metal corrosion rate, the weighed photoresist was poured into a stripping solution stabilized at 50°C in portions. The agglomeration of the photoresist at the bottom of the beaker was observed, as well as its gradual reduction over time until it completely dissolved in the solution. The volume and lifespan of the stripping solution were determined by the amount of photoresist in the solution.

[0104] Detection method:

[0105] For copper (Å / min), with a fixed etching time, the etching rate is obtained by measuring the film thickness of the copper sheet before and after etching using a four-point thickness gauge. For aluminum (Å / min), with a fixed etching time, the etching rate is obtained by measuring the film thickness of the aluminum sheet before and after etching using a four-point thickness gauge. For molybdenum (Å / min), with a fixed etching time, the etching rate is obtained by measuring the film thickness of the molybdenum sheet before and after etching using a four-point thickness gauge.

[0106] Lifespan: The maximum amount of photoresist that can be dissolved in 50g of stripping solution.

[0107] Uniformity of stripping: The structural sheet coated with photoresist is placed in the stripping solution for etching. After etching, the test sheet is subjected to EDS analysis to check whether there is residual photoresist on the surface of the test sheet.

[0108] The specific test results are shown in Table 1.

[0109] Table 1

[0110]

[0111] As shown in Table 1, the sol content in Examples 1-4 was all <2.0 g / 50 g, while the sol content in Examples 5 and 6 increased to over 4 g / 50 g. This indicates that the mixture of 4-butylphenol and xylene has the best solubilizing effect. Its binding with photoresist molecules prevents photoresist aggregation, improves the contact between the stripping solution and photoresist molecules, and thus significantly increases the solubility of the photoresist in organic solvents, extending the lifespan of the stripping solution. In Example 7, multiple benzene compounds were incorporated into the formulation, resulting in a sol content in the stripping solution below 3.0 g / 50 g, which is lower than in Examples 5 and 6. In Comparative Examples 1 and 2, the formulations contained only one of benzene compounds or xylene, with sol content below 0.5 g / 50 g. Furthermore, in Example 8, the preparation method of the stripping solution formulation was simplified, resulting in a final sol content of only 0.8 g / 50 g. This indicates that the stripping solution can have a long lifespan if and only if the solubilizer in the stripping solution formulation is a preferred component and the preparation method of the stripping solution is a preferred step.

[0112] In Examples 1-3, the surface leveling agent was optimized. Compared to Examples 1, 2, and 3, the uniformity after film stripping was improved. This indicates that the surface tension of the stripping solution was increased through the combination of alcohols, thereby enhancing the wettability of the solution and photoresist molecules. The specific contact area between the photoresist molecules and the stripping solution increased, resulting in an increase in the amount of sol in the stripping solution. Among these components, 2-amino-1,3-propanediol was the most preferred. In Comparative Example 1, the surface leveling agent was lacking in the formulation, resulting in a significant reduction in the amount of residual adhesive after stripping, and the amount of sol was reduced to below 1.0 g / 50 g. This demonstrates the indispensability of the surface leveling agent.

[0113] In Examples 1-7, due to the combination of azoles and polyphenols, the etching rates of copper and silver were less than 10 Å / min. However, in Examples 1-5, without the preferred metal corrosion inhibitor combination, the etching rates of both metals were greater than 2 Å / min. In Comparative Example 3, without the addition of metal corrosion inhibitors, the etching rates of both metals increased to 10-30 Å / min; when only polyphenols were added in Comparative Examples 1 and 2, the etching rates of all three metals remained relatively fast; this indicates that the synergistic inhibitory effect of azoles and polyphenols is significant.

[0114] The specific embodiments of the present invention have been described in detail above, but are merely examples, and the present invention is not limited to the specific embodiments described above. For those skilled in the art, any equivalent modifications and substitutions to the present invention are also within the scope of the present invention. Therefore, all equivalent transformations and modifications made without departing from the spirit and scope of the present invention should be covered within the scope of the present invention.

Claims

1. A peeling solution, characterized in that, By mass percentage, it contains 10-20% surface leveling agent, 2%-10% solubilizer, 0.1%-2% metal corrosion inhibitor, and the balance is organic solvent; the surface leveling agent is one or more of 1,3-propanediol, 2-phenyl-1,3-propanediol, and 2-amino-1,3-propanediol. The solubilizer is a combination of a phenolic compound and xylene; the phenolic compound is selected from one or more of 4-butylphenol, 4-cyclohexylphenol, and 3,4-xylenol; The metal corrosion inhibitor is an azole compound and / or a polyphenol compound, wherein the azole compound is any one of louriconazole, 2-aminooxazole, 5-benzyl-1H-tetrazole, and 2-ethyl-2-zoline; The polyphenolic compound is either tannic acid or 4,4'-dihydroxybiphenyl.

2. The peeling solution according to claim 1, characterized in that: The solubilizer is a combination of phenolic compounds and xylene in a mass ratio of 1:10-20.

3. The peeling solution according to claim 1, characterized in that: The organic solvent is dichloromethane.

4. A method for preparing a peeling solution according to any one of claims 1-3, characterized in that: Its preparation method includes the following steps: A: After mixing the solubilizer and the solvent, add the surface leveling agent while stirring, mix well, and obtain solution A; B: Add a metal corrosion inhibitor to solution A and continue stirring to obtain solution B; C: After letting solution B stand for a period of time, cool it to room temperature to obtain the peeling solution.

5. The method for preparing a peeling solution according to claim 4, characterized in that: In step A, the heating temperature is raised to 30~50℃, the stirring speed is 300~500 rpm, and the mixing time is 10~20 minutes. In step B, the stirring speed is controlled at 500-800 rpm, and the time is 20-30 minutes; The settling time in step C is 10 to 24 hours.

6. The application of the stripping solution according to any one of claims 1 to 3 or the stripping solution prepared by the method of claim 4 or 5 as a photoresist stripping solution.

7. The application according to claim 6, characterized in that, The stripping solution selectively avoids etching of metals during the photoresist stripping process, and the metals include one or more combinations of copper, silver, aluminum, and molybdenum.

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