Reductive photoresist stripping liquid as well as preparation method and application thereof

Abstract

The invention discloses a reductive photoresist stripper and a preparation method and application thereof, and the reductive photoresist stripper comprises the following raw materials by mass: 30-60 parts of a ketone solvent; 30-60 parts of an aprotic polar organic solvent; 3-10 parts of quaternary ammonium base; 1-5 parts of a phenol substance; and 1-5 parts of alcohol amine. The invention also discloses a preparation method of the reductive photoresist stripping liquid and application of the reductive photoresist stripping liquid in the field of photoresist removal. On the basis of effectively removing the photoresist, the reductive photoresist stripping liquid also has a good protection effect on metal electrodes (such as Cu, Ni, Al and the like), and can effectively prevent the metal electrodes from being oxidized to generate an oxidation film. In addition, the two nucleophilic solvents are synergistically used, so that the photoresist can be more effectively removed.

Description

Technical Field

[0001] The invention belongs to the technical field of semiconductors, and in particular relates to a reducing photoresist stripping solution and a preparation method and application thereof. Background Art

[0002] In the process of manufacturing semiconductor components, a photoresist mask is formed on the surface of some materials, and the pattern is transferred after exposure. After obtaining the required pattern, the residual photoresist needs to be removed before the next process. In the process of removing the photoresist, it is required to completely remove the unnecessary photoresist, and at the same time, no corrosion of any substrate is allowed, especially the corrosion of metal aluminum and copper is strictly controlled.

[0003] At present, photoresist cleaning liquid is mainly composed of polar organic solvents, strong alkali and / or water. The photoresist on the semiconductor wafer is removed by immersing the semiconductor wafer in the cleaning liquid or washing the semiconductor wafer with the cleaning liquid. With the rapid development of semiconductors, the cleaning requirements for photoresist residues have also increased accordingly. It can be seen that finding a more effective photoresist cleaning liquid is the priority direction for the improvement of this type of photoresist cleaning liquid. Generally speaking, improving the cleaning ability of alkaline photoresist cleaning liquid is mainly achieved by increasing the alkalinity of the cleaning liquid, selecting a more effective solvent system, increasing the operating temperature and extending the operating time.

[0004] However, increasing the alkalinity of the cleaning solution and the operating temperature as well as prolonging the cleaning time often increase the corrosion of metals. Usually, the metals involved are mainly silver, tin, lead and copper. In recent years, in order to further reduce costs and improve yields, some manufacturers have begun to require that photoresist cleaning solutions can also further inhibit metal corrosion. In order to adapt to the new situation, it is necessary to develop a type of cleaning solution that has strong photoresist removal capabilities and is basically non-corrosive to metals. Summary of the invention

[0005] The main purpose of the present invention is to provide a reducing photoresist stripping solution and its preparation method and application. The technical problem to be solved by the present invention is to provide a photoresist cleaning agent with strong photoresist cleaning ability and low corrosion to semiconductor chip patterns and substrates in order to address the defects of existing photoresist cleaning solutions, such as insufficient cleaning ability or strong corrosion to semiconductor patterns and substrates.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0007] A reducing photoresist stripping solution comprises the following components in weight proportion:

[0008] 30-60 parts of ketone solvent;

[0009] 30-60 parts of aprotic polar organic solvent;

[0010] 1-15 parts of quaternary ammonium hydroxide;

[0011] 1-15 parts of phenolic substances;

[0012] 1-15 parts of alcoholamine.

[0013] As a preferred embodiment of the reducing photoresist stripping solution, the ketone solvent is selected from one or more of N-methylpyrrolidone, N-ethylpyrrolidone, N-vinylpyrrolidone, N-hydroxyethylpyrrolidone, N-dodecylpyrrolidone, N-cyclohexylpyrrolidone, 1,3-dimethyl-2-imidazolinone, 1-butyl-2-pyrrolidone, 1-benzyl 2-pyrrolidone, 1-cyclohexyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone and N-isopropylpyrrolidone.

[0014] As a preferred embodiment of the reducing photoresist stripping solution, as a preferred embodiment of the reducing photoresist stripping solution.

[0015] As a preferred embodiment of the reducing photoresist stripping solution, the ketone solvent is preferably 40-50 parts.

[0016] As a preferred embodiment of the reducing photoresist stripping solution, the non-protonic polar organic solvent is selected from at least one of dimethyl sulfoxide, ethyl methyl sulfoxide, dimethyl sulfone, diethyl sulfone, cyclopentane, N,N-dimethylformamide, N-methylformamide, N,N-dimethylacetamide, N-methylacetamide, β-propiolactone, γ-butyrolactone, γ-valerolactone, 8-caprolactone, γ-octanolactone, ethylene carbonate, propylene carbonate, and butylene carbonate.

[0017] As a preferred embodiment of the reducing photoresist stripping solution, the aprotic polar organic solvent is preferably dimethyl sulfoxide, ethyl methyl sulfoxide, dimethyl sulfone, diethyl sulfone, or sulfolane.

[0018] As a preferred embodiment of the reducing photoresist stripping solution, the aprotic polar organic solvent is preferably dimethyl sulfoxide or sulfolane.

[0019] As a preferred embodiment of the reducing photoresist stripping solution, the aprotic polar organic solvent is preferably 40-50 parts.

[0020] The ketone solvent and the non-protonic polar organic solvent are nucleophilic and have excellent solubility. They can infiltrate and swell the photoresist through nucleophilic reaction, so that the photoresist network structure swells, which is beneficial for further penetration of other components.

[0021] As a preferred embodiment of the reducing photoresist stripping solution, the quaternary ammonium base is selected from one or more of tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrabutylammonium hydroxide, choline, tri(2-hydroxyethyl)methylammonium hydroxide, diethylbis(2-hydroxyethyl)ammonium hydroxide, bis(2-hydroxyethyl)-dimethylammonium hydroxide, 4-(2-hydroxypropyl)-4-methyl hydroxide morpholine and benzyltrimethylammonium hydroxide.

[0022] As a preferred embodiment of the reducing photoresist stripping solution, the quaternary ammonium base is preferably tetramethylammonium hydroxide or tetrabutylammonium hydroxide.

[0023] As a preferred embodiment of the reducing photoresist stripping solution, the quaternary ammonium base is preferably 5-8 parts.

[0024] As an important component of photoresist stripping solution, quaternary ammonium base can quickly penetrate and dissolve photoresist through its strong alkalinity, solubilization effect, penetration and wetting properties, and surface activity, and can crack the cross-linking degree of photoresist and reduce the interfacial tension between photoresist and the underlying layer, thereby playing a key role in promoting the complete stripping of photoresist.

[0025] As a preferred embodiment of the reducing photoresist stripping solution, the phenolic substance is selected from one or more of phenol, methylphenol, methoxyphenol, tert-butylphenol, resorcinol, 5-methyl-resorcinol, 5-methoxy-resorcinol, 5-tert-butyl-resorcinol, phloroglucinol, methylphloroglucinol and butylphloroglucinol.

[0026] As a preferred embodiment of the reducing photoresist stripping solution, the phenolic substance is preferably phenol or resorcinol.

[0027] As a preferred embodiment of the reducing photoresist stripping solution, the phenol substance is preferably 3-10 parts.

[0028] The hydroxyl groups in the phenol can be adsorbed on the metal surface to form a protective film, isolating the metal from contact with the corrosive medium, thereby playing a corrosion inhibition role; at the same time, the hydroxyl groups on the phenol have reducing properties, which can effectively prevent metal oxidation.

[0029] As a preferred embodiment of the reducing photoresist stripping solution, the alcohol amine is selected from one or more of monoethanolamine, N-methylethanolamine, diethanolamine, triethanolamine, isopropanolamine, ethyldiethanolamine, N,N-diethylethanolamine, N-(2-aminoethyl)ethanolamine, and diglycolamine.

[0030] As a preferred embodiment of the reducing photoresist stripping solution, the alcoholamine is preferably monoethanolamine, diethanolamine, or isopropanolamine.

[0031] As a preferred embodiment of the reducing photoresist stripping solution, the alcohol amine is preferably 3-10 parts.

[0032] The alcohol amine can undergo nucleophilic addition reaction with polar groups such as carbonyl and carboxyl in the photoresist, destroy the chemical bonds formed by these functional groups, cause a certain main chain break in the photoresist, cut off the covalent bonds between macromolecular chain segments, and dissolve the photoresist after dry etching.

[0033] Another object of the present invention is to disclose a method for preparing a reducing photoresist stripping solution, which comprises the following steps:

[0034] Step 1: Add ketone solvent and phenolic substance into a container and stir for 0.5-1 hour until they are completely dissolved and the solution is clear and transparent;

[0035] Step 2: Add a non-protonic polar organic solvent and alcohol amine to the solution of step 1, and stir for 1-2 hours until all are dissolved and the solution is clear and transparent;

[0036] Step 3: Add the quaternary ammonium base to the solution of step 2 while stirring, and stir for 0.5-2 hours until it is completely dissolved and the solution is clear and transparent, thereby preparing a reducing chip photoresist stripping solution.

[0037] Furthermore, the stirring temperature is controlled below 40°C.

[0038] Furthermore, the reducing photoresist stripping solution is filtered using 0.2 μm and 0.1 μm filter elements after preparation.

[0039] Another object of the present invention is to disclose the application of a reducing photoresist stripping solution in the field of removing photoresist.

[0040] Another object of the present invention is to disclose a cleaning method of a reducing photoresist stripping solution, which comprises the following steps: placing a semiconductor wafer in a reducing chip photoresist stripping solution at 40-90° C., soaking, ultrasonicating or vibrating for 5-30 minutes, taking out and rinsing with ultrapure water, and drying with nitrogen;

[0041] Alternatively, use a single-chip machine to spray a 40-90°C reducing chip photoresist stripping liquid onto a rotating semiconductor wafer, rinse for 5-10 minutes, take it out and rinse with ultrapure water, and blow dry with nitrogen.

[0042] The beneficial effects of the present invention are:

[0043] 1) Ketone solvents and non-protonic polar organic solvents are nucleophilic and have excellent solubility. They can infiltrate and swell the photoresist through nucleophilic reaction, thus expanding the photoresist network structure and facilitating the further penetration of other components.

[0044] 2) The phenolic hydroxyl groups in phenolic substances can be adsorbed on the metal surface to form a protective film, isolating the metal from contact with the corrosive medium, thereby playing a corrosion inhibition role; at the same time, the hydroxyl groups on phenol are reducing and can effectively prevent metal oxidation.

[0045] 3) The photoresist stripping solution of the present invention uses quaternary ammonium base and alcohol amine, both of which are alkaline and can destroy the cross-linked molecules of the photoresist, thereby maintaining the activity of the photoresist stripping solution while ensuring the stripping rate.

[0046] In summary, the present invention is used for stripping photoresists in the semiconductor chip industry, and while ensuring the photoresist stripping capability, it has a good reduction protection effect on easily oxidized metal electrodes such as Cu, Ni, and Al. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work, and all of them belong to the protection scope of the present invention, among which:

[0048] Attached Figure 1 is a magnified microscope picture of a chip after cleaning with the reducing photoresist stripping solution prepared in Example 1;

[0049] Attached Figure 2 This is a magnified microscope picture of a chip after cleaning with the reducing photoresist stripping solution prepared in Comparative Example 1;

[0050] Attached Figure 3 This is an enlarged microscope picture of the chip after being cleaned with the reducing photoresist stripping solution prepared in Comparative Example 2. DETAILED DESCRIPTION

[0051] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0052] Unless otherwise stated, the units used in the specification are international standard units, and the numerical values ​​and numerical ranges appearing in the present invention should be understood to include the inevitable systematic errors in industrial production.

[0053] In the present description, a numerical range expressed using "a numerical value A - a numerical value B" means a range including the numerical values ​​A and B at the endpoints.

[0054] In the present description, a numerical range expressed using "above" or "below" means a numerical range including the numerical value.

[0055] In this specification, the word “may” means both performing a certain process and not performing a certain process.

[0056] In this specification, the use of "optional" or "optional" indicates that certain substances, components, execution steps, application conditions and other factors are used or not used.

[0057] In this specification, when "normal temperature" or "room temperature" is used, the temperature may be 15-25°C.

[0058] In this description, the reagents or instruments used without indicating the manufacturer are all conventional products that can be obtained through commercial purchase.

[0059] Examples 1-10

[0060] The present embodiments 1-10 disclose a variety of reducing photoresist stripping solutions, the components and weight ratios of which are shown in Table 1, and the preparation methods thereof are as follows:

[0061] Step 1: Add ketone solvent and phenolic substance into a container and stir for 0.5-1 hour until they are completely dissolved and the solution is clear and transparent;

[0062] Step 2: Add a non-protonic polar organic solvent and alcohol amine to the solution of step 1, and stir for 1-2 hours until all are dissolved and the solution is clear and transparent;

[0063] Step 3: Add the quaternary ammonium base to the solution of step 2 while stirring, and stir for 0.5-2 hours until it is completely dissolved and the solution is clear and transparent, thereby preparing a reducing chip photoresist stripping solution.

[0064] After the reducing photoresist stripping solution is prepared, it is filtered using 0.2um and 0.1um filter elements.

[0065] The above stirring temperature is controlled below 40°C

[0066] Table 1 Components and weight ratios of reducing photoresist stripping solutions of Examples 1-10

[0067]

[0068]

[0069] Comparative Examples 1-3

[0070] Comparative Examples 1-3 disclose a variety of reducing photoresist stripping solutions, the components and weight ratios of which are shown in Table 2, and the preparation methods thereof are the same as those of Example 1.

[0071] Table 2 shows the components and weight ratios of the reducing photoresist stripping solutions of Comparative Examples 1-3.

[0072]

[0073] About the stripping method of the stripping solution in the present invention:

[0074] Place the semiconductor round in a reducing chip photoresist stripping solution at 40-90°C, soak, ultrasonicate or vibrate for 5-30 minutes, take out, rinse with ultrapure water, and blow dry with nitrogen;

[0075] Alternatively, use a single-chip machine to spray a 40-90°C reducing chip photoresist stripping liquid onto a rotating semiconductor wafer, rinse for 5-10 minutes, take it out and rinse with ultrapure water, and blow dry with nitrogen.

[0076] Table 3 Wafer cleaning conditions of the embodiments and comparative examples

[0077]

[0078]

[0079] Corrosion condition: ◎Basically no corrosion; Cleaning condition: ◎Completely removed;

[0080] O slightly corroded; O a small amount of residue;

[0081] △ Moderate corrosion; △ More residue;

[0082] x Severe corrosion. x Large amount of residue.

[0083] It can be seen from Table 3 that the cleaning solution of the present invention has a good cleaning effect on thick film photoresist, has a wide operating temperature range, and can effectively inhibit the corrosion of metals such as copper, aluminum, tin, lead, and silver.

[0084] In summary, the advantages of the present invention are:

[0085] 1) A ketone solvent is mixed with a non-protonic polar organic solvent to expand the photoresist network structure through nucleophilic reaction, penetration, and expansion of the photoresist, which is conducive to further penetration of other components.

[0086] 2) Phenol substances are used as protective agents. The phenolic hydroxyl groups can be adsorbed on the metal surface to form a protective film, isolating the metal from contact with the corrosive medium, thereby playing a corrosion inhibition role; at the same time, the hydroxyl groups on phenol are reducing and can effectively prevent metal oxidation.

[0087] 3) A mixed system of quaternary ammonium base and alcohol amine is used. Both of them are alkaline and can destroy the cross-linked molecules of the photoresist, while ensuring the degumming rate and maintaining the activity of the photoresist stripping solution.

Claims

1. A reducing photoresist stripping solution, characterized in that: The composition includes the following components in weight ratio: 30-60 parts of ketone solvent; 30-60 parts of aprotic polar organic solvent; 1-15 parts of quaternary ammonium hydroxide; 1-15 parts of phenolic substances; 1-15 parts of alcoholamine.

2. The reducing photoresist stripping solution according to claim 1, characterized in that: The ketone solvent is selected from one or more of N-methylpyrrolidone, N-ethylpyrrolidone, N-vinylpyrrolidone, N-hydroxyethylpyrrolidone, N-dodecylpyrrolidone, N-cyclohexylpyrrolidone, 1,3-dimethyl-2-imidazolinone, 1-butyl-2-pyrrolidone, 1-benzyl 2-pyrrolidone, 1-cyclohexyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone and N-isopropylpyrrolidone.

3. The reducing photoresist stripping solution according to claim 1, characterized in that: The aprotic polar organic solvent is selected from at least one of dimethyl sulfoxide, ethyl methyl sulfoxide, dimethyl sulfone, diethyl sulfone, cyclopentane, N,N-dimethylformamide, N-methylformamide, N,N-dimethylacetamide, N-methylacetamide, β-propiolactone, γ-butyrolactone, γ-valerolactone, 8-caprolactone, γ-octanolactone, ethylene carbonate, propylene carbonate, and butylene carbonate.

4. The reducing photoresist stripping solution according to claim 1, characterized in that: The quaternary ammonium base is selected from one or more of tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrabutylammonium hydroxide, choline, tri(2-hydroxyethyl)methylammonium hydroxide, diethylbis(2-hydroxyethyl)ammonium hydroxide, bis(2-hydroxyethyl)-dimethylammonium hydroxide, 4-(2-hydroxypropyl)-4-methyl hydroxide morpholine and benzyltrimethylammonium hydroxide.

5. The reducing photoresist stripping solution according to claim 4, characterized in that: The phenolic substance is selected from one or more of phenol, methylphenol, methoxyphenol, tert-butylphenol, resorcinol, 5-methyl-resorcinol, 5-methoxy-resorcinol, 5-tert-butyl-resorcinol, phloroglucinol, methylphloroglucinol and butylphloroglucinol.

6. The reducing photoresist stripping solution according to claim 4, characterized in that: The alcohol amine is selected from one or more of monoethanolamine, N-methylethanolamine, diethanolamine, triethanolamine, isopropanolamine, ethyldiethanolamine, N,N-diethylethanolamine, N-(2-aminoethyl)ethanolamine, and diglycolamine.

7. A method for preparing a reducing photoresist stripping solution as claimed in any one of claims 1 to 6, characterized in that: The following steps are involved: Step 1: Add ketone solvent and phenolic substance into a container and stir for 0.5-1 hour until they are completely dissolved and the solution is clear and transparent; Step 2: Add a non-protonic polar organic solvent and alcohol amine to the solution of step 1, and stir for 1-2 hours until all are dissolved and the solution is clear and transparent; Step 3: Add the quaternary ammonium base to the solution of step 2 while stirring, and stir for 0.5-2 hours until it is completely dissolved and the solution is clear and transparent, thereby preparing a reducing chip photoresist stripping solution.

8. Use of the reducing photoresist stripping solution according to any one of claims 1 to 6 in the field of removing photoresist.

9. A method for cleaning a reducing photoresist stripping solution as claimed in any one of claims 1 to 6, characterized in that: The method comprises the following steps: placing the semiconductor wafer in a reducing chip photoresist stripping solution at 40-90° C., soaking, ultrasonicating or vibrating for 5-30 minutes, taking out, rinsing with ultrapure water, and drying with nitrogen; Alternatively, use a single-chip machine to spray a 40-90°C reducing chip photoresist stripping liquid onto a rotating semiconductor wafer, rinse for 5-10 minutes, take it out and rinse with ultrapure water, and blow dry with nitrogen.

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