A polyvinyl cinnamate type KPR photoresist etching residue stripping agent composition

Abstract

The present invention discloses a polyvinyl alcohol cinnamate type KPR photoresist etching residue stripper composition, including: organic solvent 40-70%, organic amine 1-20%, corrosion inhibitor 0.5-10%, surfactant 0.2-5%, fluoride 1-5% and the rest of ultrapure water, wherein: the surfactant is a mixture of one or more of ethylene glycol, glycerol, glucose, sorbitol, pentaerythritol, xylitol, AEO-7; the organic amine is a mixture of one or more of monoethanolamine, triethanolamine, isopropanolamine; the corrosion inhibitor is a mixture of one or more of phenols, carboxylic acids, and benzotriazoles. Stripper of the present invention has higher cleaning efficiency, cleaning time is significantly shortened compared with similar products, and cleaning effect and protection effect on wafer substrate are better, which can significantly reduce the operating cost of semiconductor factories.

Description

Technical Field

[0001] The invention belongs to the technical field of semiconductor photoresist strippers, and in particular relates to a fluorine-containing fast stripper used for removing KPR type photoresist etching residues. Background Art

[0002] In the production of semiconductor chips, the designed pattern is transferred from the photomask to the wafer using photolithography and etching to produce the ultimate ultra-high-integration chip. The specific process involves depositing thin films (including silicon dioxide, silicon nitride, polysilicon, silicon carbide, gallium nitride, titanium, titanium nitride, cobalt, tungsten, copper, aluminum, nickel, etc.) on the wafer, applying photoresist, exposing, developing, ion implanting or etching, ashing, and cleaning. During the ion implantation or etching process, the photoresist hardens due to ion bombardment and is difficult to remove. The etching process also leaves a large amount of polymer byproducts on the wafer. Even in the subsequent ashing step, only the photoresist layer can be removed, and the remaining byproducts can only be thoroughly cleaned by the cleaning process.

[0003] In the front-end cleaning process (i.e., before the metal interconnect layer is formed), a mixture of sulfuric acid and hydrogen peroxide is generally used to remove residues after etching or ion implantation. However, after the metal interconnect layer is formed, whether it is aluminum interconnection process or copper interconnection process, the front-end cleaning method cannot be used, and special strippers must be used to clean the wafer. Obviously, the special strippers used in the back-end process must not only completely clean the residue after etching, but also consider not causing too much damage to the wafer substrate itself, especially the metal aluminum or copper, as well as silicon dioxide and silicon nitride.

[0004] Our company's primary photoresist is the KPR series, based on polyvinyl cinnamate. These photoresists offer advantages such as high resolution, etch resistance, and strong adhesion. However, after etching and ashing, conventional post-process stripper cleaning solutions can easily leave residue. Consequently, cleaning times are often long, often exceeding 20 minutes. This extended cleaning time can also lead to corrosion damage to the wafer substrate. With the development of advanced processes, metal interconnects are becoming increasingly complex, with increasing layers, and the number of cleaning cycles required for single wafer production is increasing. Longer cleaning times lead to high occupancy rates for cleaning equipment, forcing semiconductor fabs to purchase more equipment and occupy more cleanrooms to meet the growing cleaning demand. The purchase of semiconductor equipment, the use of strippers, and the operation of cleanrooms are all significant components of semiconductor fab operating costs. Therefore, reducing cleaning time and improving cleaning efficiency are key cost-cutting measures for semiconductor fabs. Summary of the Invention

[0005] Purpose of the invention: In view of the above existing problems and shortcomings, the purpose of the present invention is to provide a polyvinyl cinnamate-based KPR photoresist etching residue stripper composition.

[0006] Technical solution: To achieve the above-mentioned purpose, the present invention adopts the following technical solution: a polyvinyl cinnamate-based KPR photoresist etching residue stripper composition, comprising:

[0007]

[0008] and the remaining ultrapure water, the sum of the mass percentages of each component is 100%, where:

[0009] The surfactant is a mixture of one or more of ethylene glycol, glycerol, glucose, sorbitol, pentaerythritol, xylitol, and AEO-7;

[0010] The organic solvent is a mixture of one or more organic solvents selected from ethers, ketones and amides;

[0011] The organic amine is a mixture of one or more of monoethanolamine, triethanolamine, and isopropanolamine;

[0012] The corrosion inhibitor is a mixture of one or more of phenols, carboxylic acids, and benzotriazoles;

[0013] The fluoride is a mixture of one or more of ammonium bifluoride, tetramethylammonium fluoride, tetraethylammonium fluoride, tetrabutylammonium fluoride, hydrogen fluoride, and ammonium fluoride.

[0014] Preferably, the surfactant is a mixture of one or more of AEO-7, glycerol, pentaerythritol, sorbitol, ethylene glycol, glucose, and xylitol.

[0015] Preferably, the surfactant is a mixture of glycerol and pentaerythritol.

[0016] Preferably, the ether organic solvent is a mixture of one or more of diethylene glycol monomethyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, and dipropylene glycol monobutyl ether.

[0017] Preferably, the ketone organic solvent is a mixture of one or more of acetone, imidazolidone, pyrrolidone and imidazolinone.

[0018] Preferably, the amide organic solvent is dimethylformamide and / or dimethylacetamide.

[0019] Preferably, the corrosion inhibitor is a mixture of one or more of sodium benzoate, methylbenzotriazole, sebacic acid, ethylenediaminetetraacetic acid, sodium nitrite, gallic acid, and 1,2-dihydroxyphenol.

[0020] Preferably, the corrosion inhibitor is any combination of benzoic acid and methylbenzotriazole, sodium benzoate and sebacic acid, and sebacic acid / sodium nitrite.

[0021] Preferably, the polyvinyl cinnamate-based KPR photoresist etching residue stripper composition comprises the following components in percentage by mass:

[0022]

[0023] and the remaining ultrapure water, the sum of the mass percentages of each component is 100%, where:

[0024] The corrosion inhibitor is any combination of sodium benzoate and methylbenzotriazole, sodium benzoate and sebacic acid, or sebacic acid and sodium nitrite in a mass ratio of 1:1;

[0025] The surfactant is glycerol and pentaerythritol in a mass ratio of 1:1, or fatty alcohol polyoxyethylene ether AE0-7.

[0026] The present invention also provides a method for removing photoresist etching residues by using the above-mentioned stripper composition. At a temperature of 20 to 60° C., the stripper is brought into contact with the etched and ashed semiconductor chip by spraying to clean it. Then, the semiconductor chip is subjected to an oscillation treatment using ultrasonic, megasonic, shaking or rotating oscillation. Subsequently, the semiconductor chip is rinsed with pure water or ultrapure water at 10 to 30° C., and finally dried by centrifugation and / or IPA steam.

[0027] Beneficial effects: Compared with the prior art, the stripping agent of the present invention can be applied to the cleaning process of semiconductor chips using KRP photoresist structure for aluminum interconnection or copper interconnection. It can quickly clean the photoresist residues after etching and ashing of the semiconductor chips. The cleaning time is significantly shortened compared with similar products, and the cleaning effect and protection effect on the wafer substrate are good, which can significantly reduce the operating costs of semiconductor factories. DETAILED DESCRIPTION

[0028] The present invention is further illustrated below with reference to specific examples. It should be understood that these examples are only used to illustrate the present invention and are not used to limit the scope of the present invention. After reading the present invention, modifications of various equivalent forms of the present invention made by those skilled in the art all fall within the scope defined by the claims attached to this application.

[0029] Examples 1 to 39

[0030] The KPR photoresist etch residue strippers described in Examples 1 to 39 of the present invention were prepared by mixing the components and proportions shown in Tables 1 and 2. Examples 1 to 10 tested the effects of different surfactants on cleaning performance; Examples 11 to 21 tested the effects of different corrosion inhibitor combinations on cleaning performance and test wafer corrosion; and the remaining examples were used to explore the effects of other components and proportions on the cleaning performance of KPR photoresist residues.

[0031] Table 1 shows the components of the stripping agents of Examples 1 to 33.

[0032]

[0033]

[0034] Table 2 Mass percentage content and cleaning time of each component in Examples 1 to 33.

[0035]

[0036]

[0037] Comparative Examples 1 to 17:

[0038] The photoresist components and ratios of Comparative Examples D1 to D17 of the present invention are detailed in Tables 3 and 4. Comparative Examples 1 to 12 are primarily used to evaluate the cleaning performance of the stripper of the present invention in the absence of a surfactant; Comparative Examples 13 to 17 are used to evaluate the cleaning performance in the presence of a non-polyol surfactant.

[0039] Table 3 shows the components of the photoresists described in Comparative Examples D1 to D17.

[0040]

[0041]

[0042] Table 4 shows the content of each component in the photoresist of comparative examples D1 to D15.

[0043]

[0044]

[0045] Stripper cleaning test method and evaluation:

[0046] 1. Testing the Stripper Cleaning and Cleaning Effect of Semiconductor Chips After Etching and Ashing: Each of the above Examples and Comparative Examples was mixed and filtered in proportion. A 5L sample was placed in a spray cleaning apparatus. Semiconductor chips, after etching and ashing using commercially available KPR photoresist from Jiangsu Nada Optoelectronics, were placed in the apparatus and cleaned using a spray method. After cleaning, the chips were rinsed with ultrapure water and dried by centrifugation. Finally, the cleaning effect was examined using a scanning electron microscope (SEM). The cleaning time for each Example and Comparative Example was 1 minute and 30 minutes, respectively. The cleaning results are shown in Tables 5 and 6.

[0047] 2. Corrosion effect test of different blank wafers:

[0048] Corrosion test method for blank wafer metal aluminum, blank wafer metal copper, blank wafer metal titanium, blank wafer metal tungsten:

[0049] The surface resistance of a 4x4cm blank wafer is measured using a four-point probe to obtain the thickness before the film is formed. The wafer with the measured thickness before is immersed in a stripper kept at a constant temperature of 30-60°C. After 30 minutes, the wafer is taken out and rinsed with ultrapure water, then blown dry with high-purity nitrogen. The surface resistance is then tested using a four-point probe to obtain the thickness after the film is cleaned. The corrosion rate of the stripper on the metal aluminum film can be calculated.

[0050] Blank wafer tetraethoxysilane (TEOS), blank wafer silicon nitride (PE Si3N4) corrosion test method:

[0051] The specific operation for the corrosion of tetraethoxysilane (TEOS) on blank wafers is as follows: the thickness of the 4x4cm blank TEOS wafer is measured with FE3000, and the TEOS wafer with the measured thickness is immersed in a stripper kept at a constant temperature of 30-60°C. After 30 minutes, the TEOS wafer is taken out and rinsed with ultrapure water, and then blown dry with high-purity nitrogen. The thickness of the TEOS film is then tested with FE3000. The corrosion rate of the stripper on the TEOS film can be obtained by calculation. The corrosion results are shown in Tables 5 and 6.

[0052] The specific operation for the corrosion of blank silicon nitride wafer (PE Si3N4) is as follows: the thickness of the 4x4cm blank silicon nitride wafer is measured by FE3000, and the silicon nitride wafer with the measured thickness is immersed in a stripper kept at a constant temperature of 30-60°C. After 30 minutes, the silicon nitride wafer is taken out and rinsed with ultrapure water, and then blown dry with high-purity nitrogen. The thickness of the silicon nitride film is then measured by FE3000. The corrosion rate of the stripper on the silicon nitride film can be obtained by calculation. The corrosion test results are shown in Tables 5 and 6.

[0053] Table 5 shows the corrosion effects of different blank wafers after being cleaned by the stripping solutions of various embodiments of the present invention.

[0054]

[0055]

[0056] Table 6 shows the corrosion effects of different blank wafers after cleaning with different comparative example stripping solutions.

[0057]

[0058]

[0059] The meaning of the symbols in Tables 5 and 6

[0060]

[0061] From the comparison of the cleaning results of Examples B1-B33 and Comparative Examples D1-D15, it can be seen that:

[0062] From the results of comparative examples D1-D15, it can be seen that the stripping solution without adding surfactants still has a lot of photoresist residue after 10 minutes of cleaning. The cleaning effect is improved after adding surfactants such as 5-sulfosalicylic acid, isooctyl ether phosphate, sodium dodecylbenzenesulfonate, distyrylphenol polyoxyethylene ether, and vinyl bisstearamide, but there is still a gap compared with the effects of Examples 1 to 33 of the present invention.

[0063] The strippers of Examples B1 to B33 of the present invention can achieve complete stripping without residue after 10 minutes of cleaning. The Examples B10 to B21 using a combination of propylene glycol and pentaerythritol, or two surfactants AEO-7, can achieve complete removal without residue after 1 minute of cleaning, which greatly improves the cleaning efficiency and shortens the cleaning time. Therefore, it can be seen that the strippers of Examples B1 to B33 of the present invention have significantly improved the cleaning effect of etching residual glue. In addition, Examples B23 to B33 of the present invention explore the cleaning effect of other organic solvents in combination with surfactants and corrosion inhibitors. It can be seen from the results that complete removal can be achieved within 10 minutes of cleaning time. From the test results, it can be seen that the corrosion inhibitor using a combination of at least two of sodium benzoate, methylbenzotriazole, sebacic acid, and sodium nitrite has the best corrosion inhibition effect and can achieve basically no corrosion effect.

[0064] The stripping agent of the present invention can significantly improve the cleaning efficiency of semiconductor chips, and helps semiconductor factories reduce the occupancy rate of cleaning equipment, thereby achieving the effect of reducing the purchase of cleaning equipment and reducing production and operation costs.

[0065] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A polyvinyl cinnamate type KPR photoresist etching residue stripping agent composition, characterized in that include: Organic solvent 40~70% Organic amine 1~20% Corrosion inhibitor 0.5~10% Surfactant 0.2~5% Fluoride 1~5% And the rest of the ultrapure water, the sum of the mass percentages of each component is 100%, where: The organic solvent is a mixture of one or more of ether, ketone and amide organic solvents; The organic amine is a mixture of one or more of monoethanolamine, triethanolamine and isopropanolamine; The fluoride is a mixture of one or more of ammonium bifluoride, tetramethylammonium fluoride, tetraethylammonium fluoride, tetrabutylammonium fluoride, hydrogen fluoride and ammonium fluoride; The surfactant is a mixture of glycerol and pentaerythritol; The corrosion inhibitor is any combination of benzoic acid and methylbenzotriazole, sodium benzoate and sebacic acid, and sebacic acid and sodium nitrite.

2. The polyvinyl cinnamate type KPR photoresist etching residue stripping agent composition according to claim 1, characterized in that: The ether organic solvent is a mixture of one or more of diethylene glycol monomethyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether and dipropylene glycol monobutyl ether.

3. The polyvinyl cinnamate type KPR photoresist etching residue stripping agent composition according to claim 1, characterized in that: The ketone organic solvent is a mixture of one or more of acetone, imidazolidinone, pyrrolidone and imidazolinone.

4. The polyvinyl cinnamate type KPR photoresist etching residue stripping agent composition according to claim 1, characterized in that: The amide organic solvent is dimethylformamide and / or dimethylacetamide.

5. The polyvinyl cinnamate type KPR photoresist etching residue stripping agent composition according to claim 1, characterized in that The following components are included in mass percentage: Diethylene glycol monomethyl ether 40~60% Triethanolamine 5~10% Ammonium bifluoride 2~5% Corrosion inhibitor 2~5% Surfactant 2~5% And the rest of the ultrapure water, the sum of the mass percentages of each component is 100%, where: The corrosion inhibitor is any combination of sodium benzoate and methyl benzotriazole, sodium benzoate and sebacic acid, and sebacic acid and sodium nitrite in a mass ratio of 1:1; The surfactant is propylene glycol and pentaerythritol in a mass ratio of 1:

1.

6. A method for removing photoresist etching residues using the stripper composition according to any one of claims 1 to 5, characterized in that: At a temperature of 20-60° C., the stripper composition is contacted with the etched and ashed semiconductor chip for cleaning by spraying, and then subjected to an oscillation treatment by ultrasonic, megasonic, shaking or rotating oscillation, followed by rinsing with pure water or ultrapure water at 10-30° C., and finally completed by centrifugal drying and / or IPA steam drying.

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