Film stripping liquid and preparation method thereof

Abstract

The invention provides a film stripping liquid and a preparation method thereof. The film stripping liquid is composed of a solubilizer, a metal corrosion inhibitor, a surface leveling agent and an organic solvent. Wherein the solubilizer can be a combination containing benzene series, so that the solubility of the photoresist in an organic solvent can be improved, and the service life of the stripping liquid is prolonged. The surface leveling agent is one or more of 1, 3-propylene glycol, 2-phenyl-1, 3-propylene glycol and 2-amino-1, 3-propylene glycol, and is used for improving the uniformity of the film stripping liquid in the film stripping process and avoiding the uneven concave-convex phenomenon on the surface of the photoresist. The metal corrosion inhibitor can be selected from azole or polyphenol compounds and can inhibit corrosion of metals such as Cu and Ag in the film stripping process; and the organic solvent is a combination of xylene and dichloromethane and is mainly used for dissolving and removing the expanded and fallen photoresist. According to the film stripping liquid provided by the invention, the glue stripping speed can be increased, the glue stripping uniformity can be remarkably improved, in addition, metals can be effectively protected from being corroded, and the corrosion speed of the metals such as Cu and Ag is controlled to be limited below 1 A / min.

Description

Technical Field

[0001] The invention belongs to the technical field of semiconductors, and in particular relates to a film stripping solution and a preparation method thereof, which are suitable for pattern transfer and film stripping operations of ultra-fine circuits in a semiconductor manufacturing process. Background Art

[0002] As the demand for ultra-fine circuits in semiconductor manufacturing continues to increase, the stripping effect during the pattern transfer process has a crucial impact on the accuracy of the process. However, the existing stripping solution is prone to dry film residue when removing the dry film in the ultra-fine circuit, which makes it difficult to meet the high-precision requirements. This phenomenon may affect the stability and reliability of subsequent processes, resulting in a decrease in process quality. Therefore, in order to meet the stripping needs of ultra-fine circuits, it is necessary to improve the formula of the existing stripping solution. Summary of the invention

[0003] The present invention provides a film stripping liquid and a preparation method thereof, which can increase the rate of film stripping and significantly improve the uniformity of film stripping. In addition, the film stripping liquid can effectively protect metals from corrosion and control the corrosion rate of metals such as Cu and Ag to be less than 1 A / min.

[0004] In order to achieve the above objectives, the present invention adopts the following technical solution, which contains, by mass percentage, 10-20% of a surface leveler, 2%-10% of a solubilizer, 0.1%-2% of a metal corrosion inhibitor, and the remainder is an organic solvent.

[0005] Furthermore, the surface leveler is one or more of 1,3-propylene glycol, 2-phenyl-1,3-propylene glycol, and 2-amino-1,3-propylene glycol.

[0006] Furthermore, the solubilizing agent is a composition of a phenol compound and xylene in a mass ratio of 1:10-20; the phenol 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 the phenol compound and xylene at 120° C.-130° C. for 20-30 minutes.

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

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

[0011] Furthermore, the polyphenol compound is any one of tannic acid or 4,4'-dihydroxybiphenyl.

[0012] Furthermore, the organic solvent is dichloromethane.

[0013] Furthermore, the preparation method thereof comprises the following steps: A: Add the solubilizer and dichloromethane into a stirring kettle, add the surface leveler, mix well, and obtain solution A.

[0014] B: Add metal corrosion inhibitor to solution A and continue stirring to obtain solution B.

[0015] C: After solution B is left to stand for a period of time and then cooled to room temperature, the preliminarily prepared stripping solution is obtained for filling.

[0016] Furthermore, in step A, the stirring rate is controlled at 300-500 rpm for 10-20 minutes.

[0017] Furthermore, in step A, the heating temperature is maintained at 30-50°C.

[0018] Furthermore, in step B, the stirring rate is controlled at 500-800 rpm for 20-30 minutes.

[0019] Furthermore, the standing time in step C is 10 hours to 24 hours.

[0020] The present invention has the following beneficial effects: The solubilizing agent in the stripping solution can increase the solubility of the photoresist in the organic solvent and extend the service life of the stripping solution. The surface leveler is used to improve the uniformity of the stripping solution during the stripping process to avoid uneven bumps 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, which is mainly used to dissolve and remove the swollen and detached photoresist. The stripping solution provided by the present invention can increase the stripping rate and significantly improve the uniformity of stripping. In addition, it can effectively protect the metal from corrosion and control the corrosion rate of metals such as Cu and Ag to be limited to less than 1 A / min. DETAILED DESCRIPTION

[0021] The embodiments of the present invention will be described in detail below with reference to examples.

[0022] Embodiment 1: A film stripping solution and a preparation method thereof, comprising the following: A mixture of 8wt% 3,4-dimethylphenol and xylene (mass ratio is 1:10), 10wt% 1,3-propylene glycol, 1wt% luliconazole, 1wt% tannic acid, and the balance is dichloromethane. In this embodiment, the preparation method comprises the following steps: A: Stir 3,4-dimethylphenol and xylene at 120°C-130°C for 30 minutes to obtain a solubilizer, add the solution and dichloromethane into a stirring kettle, add a surface leveler, mix well, and obtain solution A.

[0023] B: Add metal corrosion inhibitor to solution A and continue stirring to obtain solution B.

[0024] C: After solution B is left to stand for a period of time and then cooled to room temperature, the preliminarily prepared stripping solution is obtained for filling.

[0025] In this embodiment, the stirring rate in step A is controlled at 400 rpm for 20 minutes.

[0026] In this embodiment, the heating temperature in step A is maintained at 50°C.

[0027] In this embodiment, the stirring rate in step B is controlled at 800 rpm for 30 minutes.

[0028] In this embodiment, the standing time in step C is 10 hours.

[0029] Embodiment 2: A film stripping solution and a preparation method thereof, comprising the following: 8wt% mixture of 3,4-dimethylphenol and xylene (mass ratio is 1:10), 10wt% 2-phenyl-1,3-propanediol, 1wt% 5-benzyl-1H-tetrazole, 1wt% tannic acid, and the balance is dichloromethane. In this embodiment, the preparation method is the same as that in Example 1.

[0030] Embodiment 3: A film stripping solution and a preparation method thereof, comprising the following: 8wt% mixture of 3,4-dimethylphenol and xylene (mass ratio is 1:10), 10wt% 2-amino-1,3-propanediol, 1wt% 2-ethyl-2-oxazoline, 1wt% tannic acid, and the balance is dichloromethane. In this embodiment, the preparation method is the same as that in Example 1.

[0031] Embodiment 4: A film stripping solution and a preparation method thereof, comprising the following: A mixture of 8wt% 4-cyclohexylphenol and xylene (mass ratio is 1:10), 10wt% 2-amino-1,3-propanediol, 1wt% 2-aminooxazole, 1wt% tannic acid, and the balance is dichloromethane. In this embodiment, the preparation method is the same as that in Example 1.

[0032] Embodiment 5: A film stripping solution and a preparation method thereof, comprising the following: A mixture of 8wt% 4-butylphenol and xylene (mass ratio is 1:10), 10wt% 2-amino-1,3-propanediol, 1wt% luliconazole, 1wt% tannic acid, and the balance is dichloromethane. In this embodiment, the preparation method is the same as that in Example 1.

[0033] Embodiment 6: A film stripping solution and a preparation method thereof, comprising the following: A mixture of 8wt% 4-butylphenol and xylene (mass ratio is 1:10), 10wt% 2-amino-1,3-propanediol, 1wt% luliconazole, 1wt% 4,4'-dihydroxybiphenyl, and the balance is dichloromethane. In this embodiment, the preparation method is the same as that in Example 1.

[0034] Embodiment 7: A film stripping solution and a preparation method thereof, comprising the following: A mixture of 8wt% 4-butylphenol, 4-cyclohexylphenol and xylene (mass ratio is 1:1:20), 10wt% 2-amino-1,3-propanediol, 1wt% luliconazole, 1wt% 4,4'-dihydroxybiphenyl, and the balance is dichloromethane. In this embodiment, the preparation method is the same as that in Example 1.

[0035] Embodiment 8: A film stripping solution and a preparation method thereof, comprising the following: 0.73% 3,4-dimethylphenol, 7.3% xylene, 10wt% 1,3-propylene glycol, 1wt% luliconazole, 1wt% tannic acid, and the balance is dichloromethane. In this embodiment, the preparation method comprises the following steps: A: 3,4-dimethylphenol, xylene and dichloromethane are mixed and added into a stirring tank, and a surface leveling agent is added and mixed evenly to obtain solution A.

[0036] B: Add metal corrosion inhibitor to solution A and continue stirring to obtain solution B.

[0037] C: After solution B is left to stand for a period of time and then cooled to room temperature, the preliminarily prepared stripping solution is obtained for filling.

[0038] In this embodiment, the stirring rate in step A is controlled at 400 rpm for 20 minutes.

[0039] In this embodiment, the heating temperature in step A is maintained at 30-50°C.

[0040] In this embodiment, the stirring rate in step B is controlled at 800 rpm for 30 minutes.

[0041] In this embodiment, the standing time in step C is 10 hours.

[0042] Comparative Example 1: A film stripping solution and a preparation method thereof, comprising the following: 8wt% xylene, 10wt% 1,3-propylene glycol, 1wt% luliconazole, and the balance is dichloromethane. In this embodiment, the preparation method comprises the following steps: A: Mix xylene and dichloromethane and add them into a stirring tank, add a surface leveling agent, mix well, and obtain solution A.

[0043] B: Add metal corrosion inhibitor to solution A and continue stirring to obtain solution B.

[0044] C: After solution B is left to stand for a period of time and then cooled to room temperature, the preliminarily prepared stripping solution is obtained for filling.

[0045] In this embodiment, the stirring rate in step A is controlled at 400 rpm for 20 minutes.

[0046] In this embodiment, the heating temperature in step A is maintained at 30-50°C.

[0047] In this embodiment, the stirring rate in step B is controlled at 800 rpm for 30 minutes.

[0048] In this embodiment, the standing time in step C is 10 hours.

[0049] Comparative Example 2: A film stripping solution and a preparation method thereof, comprising the following: 8wt% 4-butylphenol, 10wt% 2-amino-1,3-propanediol, 1wt% 4,4'-dihydroxybiphenyl, and the balance is dichloromethane. In this embodiment, the preparation method comprises the following steps: A: Add 4-butylphenol and dichloromethane into a stirring kettle, add a surface leveler, mix well, and obtain solution A.

[0050] B: Add metal corrosion inhibitor to solution A and continue stirring to obtain solution B.

[0051] C: After solution B is left to stand for a period of time and then cooled to room temperature, the preliminarily prepared stripping solution is obtained for filling.

[0052] In this embodiment, the stirring rate in step A is controlled at 400 rpm for 20 minutes.

[0053] In this embodiment, the heating temperature in step A is maintained at 30-50°C.

[0054] In this embodiment, the stirring rate in step B is controlled at 800 rpm for 30 minutes.

[0055] In this embodiment, the standing time in step C is 10 hours.

[0056] Comparative Example 3: A film stripping solution and a preparation method thereof, comprising the following: 5wt% 4-cyclohexylphenol, 3wt% 3,4-xylenol, 10wt% 2-amino-1,3-propanediol, and the balance is dichloromethane. In this embodiment, the preparation method comprises the following steps: A: 4-cyclohexylphenol, 3,4-xylenol and dichloromethane were mixed and added into a stirring tank, and a surface leveling agent was added and mixed evenly to obtain solution A.

[0057] B: After solution A is left to stand for a period of time and then cooled to room temperature, the preliminarily prepared stripping solution is obtained for filling.

[0058] In this embodiment, the stirring rate in step A is controlled at 400 rpm for 20 minutes.

[0059] In this embodiment, the heating temperature in step A is maintained at 30-50°C.

[0060] In this embodiment, the standing time in step A is 10 hours.

[0061] The stripping solutions obtained in the above embodiments and comparative examples were tested to understand the corrosion data of the stripping solutions on the metal layer by testing the etching conditions of the metal layer monolithic wafer, wherein the etching temperature was 50° C. and the etching time was 10 min.

[0062] Specifically, the stripping solution is prepared in a beaker according to its composition. After completion, 50 g is weighed and put into a constant temperature water bath at 50°C. After the stripping solution temperature reaches 50°C and stabilizes for a period of time, the copper and silver metal sheets are cut into the same size with a glass knife, rinsed with ultrapure water, and purged with nitrogen. The film thickness of the copper and silver sheets before etching is measured with a four-probe thickness gauge. The copper and silver sheets are then fixed with a rack, suspended and immersed in an etching solution at 50°C. After etching for 10 minutes, the copper and silver sheets are taken out, rinsed with ultrapure water, purged with nitrogen, and the film thickness of the copper and silver after etching is tested with a four-probe thickness gauge. The corrosion rate of the stripping solution on the metal is obtained by the change in film thickness before and after etching.

[0063] After obtaining the metal corrosion rate, pour the weighed photoresist into the stripping solution stabilized at 50°C in batches to observe whether the photoresist aggregates at the bottom of the beaker, whether it slowly decreases over time, and finally completely dissolves into the solution. The capacity and life of the stripping solution can be obtained by the amount of sol in the stripping solution.

[0064] Detection method: Copper (Å / min) Fixed etching time, using a four-probe thickness gauge to measure the film thickness of the copper sheet before and after etching, the copper etching rate is obtained. Aluminum (Å / min) Fixed etching time, using a four-probe thickness gauge to measure the film thickness of the aluminum sheet before and after etching, the aluminum etching rate is obtained. Molybdenum (Å / min) Fixed etching time, using a four-probe thickness gauge to measure the film thickness of the molybdenum sheet before and after etching, the molybdenum etching rate is obtained.

[0065] Lifespan: The maximum amount of photoresist that can be dissolved in 50g of stripping solution.

[0066] Stripping uniformity: Place the structure film coated with photoresist into the stripping solution for etching. After etching, perform EDS analysis on the test piece to check whether there is residual photoresist on the surface of the test piece.

[0067] The specific test results are shown in Table 1. Table 1

[0068] As can be seen from Table 1, the sol amount in Examples 1-4 is <2.0g / 50g, while the sol amount in Examples 5 and 6 is increased to more than 4g / 50g, indicating that the solubilizing agent prepared from the mixture of 4-butylphenol and xylene has the best effect. The combination with the photoresist molecules makes the photoresist less likely to agglomerate, improves the contact between the stripping solution and the photoresist molecules, and thereby significantly improves the solubility of the photoresist in organic solvents and prolongs the life of the stripping solution. In Example 7, a variety of benzene series are compounded into the formula, and the sol amount of the stripping solution is below 3.0g / 50g, which is lower than that of Examples 5 and 6. In Comparative Examples 1 and 2, only one of the benzene series or xylene is present in the formula, and the sol amount is less than 0.5 g / 50g; in addition, in Example 8, the preparation method of the stripping solution formula is simplified, and the sol amount of the final formula is only 0.8 g / 50g. This shows that the stripping solution can have the characteristics of high lifespan when and only when the solubilizer in the stripping solution formula is a preferred ingredient and the preparation method of the stripping solution is a preferred step.

[0069] In Examples 1-3, the surface leveler was optimized. Compared with Examples 1 and 2, the uniformity after film stripping in Example 3 was improved, which shows that the surface tension of the film stripping solution was improved by the combination of alcohols, so that the wettability of the solution and the photoresist molecules was enhanced, and the specific contact area between the photoresist molecules and the film stripping solution was expanded, which was reflected in the increase of the sol amount of the film stripping solution, among which 2-amino-1,3-propanediol was the most preferred component. In Comparative Example 1, the surface leveler was missing in the formula, and a large amount of colloid residue was reduced after film stripping, and the sol amount was also reduced to less than 1.0g / 50g, which shows that the surface leveler is indispensable.

[0070] In Examples 1-7, due to the combination of azoles and polyphenols, the etching rates of copper and silver by the solution were less than 10 Å / min. However, when the preferred metal corrosion inhibitor combination was not added in Examples 1-5, the etching rates of the two metals were greater than 2 Å / min. In Comparative Example 3, no metal corrosion inhibitor component was added, and the etching rates of the two metals increased to 10-30 Å / min; when only polyphenols were added in Comparative Examples 1 and 2, the etching rates of the three metals were still relatively fast; this shows that the synergistic inhibitory effect of azoles and polyphenols is significant.

[0071] The specific embodiments of the present invention are described in detail above, but are only used as 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 made to the present invention are also within the scope of the present invention. Therefore, the equalization changes and modifications made without departing from the spirit and scope of the present invention should be included in the scope of the present invention.

Claims

1. A film stripping solution, characterized in that: Calculated by mass percentage, it contains 10-20% of surface leveler, 2%-10% of solubilizer, 0.1%-2% of metal corrosion inhibitor, and the balance is organic solvent.

2. The film stripping solution according to claim 1, characterized in that: The surface leveling agent is one or more of 1,3-propylene glycol, 2-phenyl-1,3-propylene glycol, and 2-amino-1,3-propylene glycol.

3. The film stripping solution according to claim 1, characterized in that: The solubilizer is a composition of a phenol compound and xylene in a mass ratio of 1:10-20; the phenol compound is selected from one or more of 4-butylphenol, 4-cyclohexylphenol and 3,4-xylenol.

4. The film stripping solution according to claim 1, characterized in that: The metal corrosion inhibitor is an azole and / or polyphenol compound.

5. The film stripping solution according to claim 4, characterized in that: The azole compound is any one of luliconazole, 2-aminooxazole, 5-benzyl-1H-tetrazolyl, and 2-ethyl-2-oxazoline; the polyphenol compound is any one of tannic acid or 4,4'-dihydroxybiphenyl.

6. The film stripping solution according to claim 5, characterized in that: The organic solvent is dichloromethane.

7. A method for preparing a film stripping solution according to any one of claims 1 to 5, characterized in that: The preparation method comprises the following steps: A: After mixing the solubilizer and the solvent, add the surface leveler under stirring and mix well to obtain solution A; B: Add metal corrosion inhibitor to solution A and continue stirring to obtain solution B; C: Solution B is allowed to stand for a period of time and then cooled to room temperature to obtain a stripping solution.

8. The method for preparing a film stripping solution according to claim 7, characterized in that: In step A, the heating temperature is 30-50° C., the stirring rate is 300-500 rpm, and the mixing time is 10-20 minutes; In step B, the stirring rate is controlled at 500-800 rpm for 20-30 minutes; The standing time in step C is 10 hours to 24 hours.

9. Use of a film stripping solution as claimed in any one of claims 1 to 6 or a stripping solution prepared by the method as claimed in claim 7 or 8 as a photoresist stripping solution.

10. The use according to claim 9, characterized in that: The stripping solution selectively avoids etching of metal during the process of stripping the photoresist, and the metal includes a combination of one or more of copper, silver, aluminum, and molybdenum.

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