Aqueous stripping solution suitable for various structures, and preparation method and application thereof

Abstract

The present application belongs to the processing technology of semiconductor devices, and relates to the materials used therein, in particular to a water-based stripping solution suitable for various structures, and a preparation method and application thereof. The stripping solution comprises the following components in parts by weight: 9-10 parts of an organic amine compound, 60-70 parts of an organic solvent, 0.5-1 part of a corrosion inhibitor, and 0.5-1 part of a modified EDTA compound; the organic amine compound is hydroxyethyl ethylenediamine, methyldiethanolamine, triethanolamine or diglycolamine. The stripping solution can be suitable for various structures, and the corrosion rate is reduced by more than 20% due to the combination of the EDTA compound and the corrosion inhibitor, and the stripping speed is improved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the processing technology of semiconductor devices, and relates to the materials used therein, and particularly relates to a water-based stripping solution suitable for various structures, a preparation method and application thereof. BACKGROUND

[0002] In the manufacturing process of semiconductor and display panels, a stripping solution is a key chemical agent for removing photoresist (PR) and surface contaminants. Its performance directly affects the device yield, process efficiency and material compatibility.

[0003] In the manufacturing process of semiconductor and display panels, copper is exposed to air or wet process, and copper oxide (CuO / Cu2O) is rapidly generated on the surface, with a thickness of about 10-1000 (angstromes). The oxide layer can cause defects such as increased contact resistance and metal line circuit breakage. IGZO (InGaZnO4) is sensitive to acid and alkali, and if free H + or OH - is contained in the stripping solution, metal ions (In 3+ , Ga 3+ , Zn 2+ ) can be dissolved out, the oxide lattice structure can be destroyed, and the electron mobility can be reduced (affecting the switching performance of TFT).

[0004] Traditional stripping solutions include hydroxylamine stripping solutions, organic amine stripping solutions and fluorine-containing stripping solutions.

[0005] The main components of the hydroxylamine stripping solution are hydroxylamine (NH2OH, 30%-50%), monoethanolamine (MEA) and water-soluble solvents (such as dimethyl sulfoxide). The strong reducing property of hydroxylamine can break the cross-linking structure of photoresist, but it has strong corrosion on the oxide and metal layer. However, for the stripping of IGZO corrosion, high pH value (pH>10) leads to the dissolution of In 3+ , Ga 3+ in IGZO (the measured In dissolution amount is >10%), which causes the TFT electrical property to drift; the Cu surface oxide layer (CuO) cannot be removed, and an additional acid washing step is required; and the toxicity risk: hydroxylamine is easy to decompose to produce NOx, which is harmful to the operation safety.

[0006] The main components of the organic amine stripping solution are: monoethanolamine (MEA, 20%-40%), dimethylformamide (DMF), and surfactant. The photoresist is stripped by the penetration and swelling effect of the amine group, but the dissolution efficiency of the compact PR after baking (≥180℃) is low. Oxide layer residue: lack of redox ability, Cu surface oxide layer needs mechanical polishing or plasma cleaning; amine chelation with Nb in CuMoNb, CuMoTi, and CuTi, resulting in notching expansion (notching >0.5μm after 30min immersion at 50℃).

[0007] The main components of the fluorine-containing stripping solution are: ammonium fluoride (NH4F, 5%-15%), organic acid (such as citric acid), and deionized water. Fluoride ions corrode the oxide layer (such as CuO), but the attack is too strong. Fluoride ions react with Al to form AlF3, resulting in aluminum line perforation (corrosion rate >5nm / min); the treatment cost of fluorine-containing wastewater is high, and it violates the RoHS regulations. SUMMARY

[0008] (1) Technical problems to be solved

[0009] In view of the above-mentioned defects and deficiencies of the prior art, the present application provides a water-based stripping solution suitable for various structures, which uses a modified EDTA complex and a pre-formed EDTA-Zn complex to block the dissolution path of metal ions, and the modified EDTA complex and PBTCA have a synergistic effect on blocking the dissolution of metal ions.

[0010] Correspondingly, the present application also provides a preparation method of a water-based stripping solution suitable for various structures.

[0011] (2) Technical solutions In order to achieve the above-mentioned purpose, the main technical scheme adopted by the present application includes:

[0012] In a first aspect, the present application provides a water-based stripping solution suitable for various structures, which comprises the following components by weight: 9-10 parts of an organic amine compound, 60-70 parts of an organic solvent, 0.5-1 part of a corrosion inhibitor, and 0.5-1 part of a modified EDTA complex; the organic amine compound is hydroxyethyl ethylenediamine, methyldiethanolamine, triethanolamine, or diethyleneglycolamine.

[0013] The stripping solution of the present application can be used for water-based stripping solutions of various structures and can achieve efficient and lossless processing: for copper-based alloys (CuMoNb, CuMoTi, CuTi), the problem of oxide layer removal and notching control is solved;

[0014] For oxide semiconductors (IGZO, ITO), ion dissolution inhibition and electrical stability are achieved;

[0015] For high molecular materials (PVX photoresist), fast dissolution and no residue are ensured;

[0016] The corrosion risk of traditional fluorine-containing stripping solution can be avoided for aluminum-based structures.

[0017] The present application can realize efficient compatible processing of a single stripping solution for metals, oxides, polymers and other structures through molecular-level functional design (EDTA-Zn, ammonium molybdate). The technical effects (such as IGZO ion control, CuMoNb notch inhibition) and environmental protection (fluorine-free, low COD) are significantly better than the prior art, and have outstanding substantial features and industrial application value.

[0018] In particular, when the organic amine is hydroxyethyl ethylenediamine or / and methyldiethanolamine, the modified EDTA complex and PBTCA have a synergistic effect on blocking metal ion dissolution. In addition, EDTA-Zn pre-chelation and ammonium molybdate passivation also have a synergistic effect.

[0019] Optionally, the modified EDTA complex is an EDTA-Zn pre-chelate or / and EDDS.

[0020] The unexpected technical effects of the EDTA-Zn complex and corrosion inhibitor combination of the present application are that the corrosion rate is reduced by more than 20%, and the stripping speed is improved.

[0021] In the present application, the modified EDTA complex is used, and the pre-generated EDTA-Zn complex preferentially adsorbs on the IGZO surface, and its Zn 2+ and In 3+ / Ga 3+ in IGZO undergo ion exchange to form a more stable EDTA-In / Ga complex (logK>25), thereby blocking the metal ion dissolution path.

[0022] Experiments show that XPS analysis shows that using the modified EDTA complex, the Zn atomic concentration on the IGZO surface is increased by 3 times (after pre-chelation) relative to the same mass or molar number of traditional EDTA, and the In / Ga dissolution amount is reduced by 60%.

[0023] Optionally, the preparation method of the EDTA-Zn pre-chelate comprises the following steps:

[0024] S11 mixing EDTA with zinc sulfate at a molar ratio of 1:1, reacting at pH 4-5 and 60℃ for 2 hours;

[0025] S12 filtering after cooling to obtain white crystalline EDTA-Zn complex.

[0026] Optionally, the corrosion inhibitor is at least one of ammonium molybdate, uracil, methylphenyltriazole, mercaptobenzothiazole, benzotriazole and modified products thereof.

[0027] In a second aspect, the present application provides a preparation method of the water-based stripping solution suitable for various structures, comprising the following steps:

[0028] S1, mixing the organic solvent and the organic amine compound, and heating and stirring;

[0029] S2, sequentially adding the modified EDTA complex, the corrosion inhibitor, and water, and stirring;

[0030] S3, filtering to obtain the stripping solution.

[0031] Optionally, the preparation method comprises:

[0032] S1, mixing the organic solvent and the organic amine compound, and heating to 35-45°C and stirring until completely dissolved;

[0033] S2, sequentially adding the modified EDTA complex, the corrosion inhibitor, and deionized water, controlling the pH to be 7.5-8.2, and stirring uniformly;

[0034] S3, filtering through a 0.1-0.5 μm PTFE filter membrane to obtain the homogenized stripping solution.

[0035] Optionally, the stirring in step S2 is divided into two stages:

[0036] In the first stage, the temperature is maintained at 25-40°C, and the stirring is performed for 10-15 minutes;

[0037] In the second stage, the temperature is raised to 48-55°C, and the stirring is performed for 10-15 minutes.

[0038] In a third aspect, the present application also provides the application of the water-based stripping solution suitable for various structures in the manufacture of semiconductor and display panels.

[0039] (III) Beneficial Effects

[0040] The beneficial effects of the present application are:

[0041] The stripping solution of the present application can be suitable for various structures, and the corrosion rate is reduced by more than 20% due to the combination of the EDTA complex and the corrosion inhibitor, and the stripping speed is improved.

[0042] Among them, the EDTA-Zn pre-chelate blocks the metal ion dissolution path, and especially when the organic amine is hydroxyethyl ethylenediamine or / and methyldiethanolamine, the modified EDTA complex and PBTCA have a synergistic effect on blocking the metal ion dissolution of the stripping solution. In addition, the EDTA-Zn pre-chelate and ammonium molybdate passivation also have a synergistic effect. The stripping speed is also significantly improved. DETAILED DESCRIPTION

[0043] To explain possible application scenarios, technical principles, specific embodiments, and the like of the present application in detail, the following will be described in detail in combination with specific embodiments. The embodiments described herein are only used to more clearly illustrate the technical solutions of the present application, and therefore only serve as examples, and cannot limit the protection scope of the present application.

[0044] In this paper, the term "embodiment" means that the specific features, structures or characteristics described in combination with the embodiment can be included in at least one embodiment of the present application. The term "embodiment" appearing at various places in the specification does not necessarily refer to the same embodiment, and does not particularly limit its independence or association with other embodiments. In principle, in the present application, as long as there is no technical contradiction or conflict, each technical feature mentioned in each embodiment can be combined in any way to form a corresponding implementable technical solution.

[0045] Unless otherwise defined, the meanings of the technical terms used herein are the same as those commonly understood by those skilled in the art to which the present application belongs; the use of related terms herein is only for the purpose of describing specific embodiments, and is not intended to limit the present application.

[0046] In the description of the present application, the phrase "and / or" is a description of the logical relationship between the objects, which means that there can be three relationships, for example, A and / or B, which means that there are three cases: A exists, B exists, and A and B exist at the same time. In addition, the character " / " in this paper generally represents that the associated objects before and after are a kind of "or" logical relationship.

[0047] In the present application, such as "first" and "second", the terms are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual quantity, primary and secondary or order relationship between the entities or operations.

[0048] Without more limitations, in the present application, the phrases "include", "contain", "have" or other similar expressions used in the sentence are intended to cover non-exclusive inclusion, and these expressions do not exclude the presence of other elements in the process, method or product including the described elements, so that the process, method or product including a series of elements can not only include those limited elements, but also include other elements not explicitly listed, or also include the elements inherent in such process, method or product.

[0049] As the same as the understanding in the "Examination Guidelines", in the present application, "greater than", "less than", "exceed" and the like are understood as not including the number; "above", "below", "within" and the like are understood as including the number. In addition, in the description of the embodiments of the present application, the meaning of "multiple" is two or more (including two), and similar expressions related to "multiple" are also understood in this way, for example, "multiple groups", "multiple times" and the like, unless otherwise explicitly and specifically limited.

[0050] For those skilled in the art to which the present application belongs, the specific meanings of the above-mentioned terms in the embodiments of the present application can be understood according to specific circumstances.

[0051] Embodiment 1

[0052] The present embodiment provides a preparation method of EDTA-Zn pre-chelate, the steps of which are as follows:

[0053] EDTA disodium salt of 372.24 g / mol and zinc sulfate (ZnSO4·7H2O) of 287.54 g / mol are mixed in deionized water at a molar ratio of 1:1, and the ratio of deionized water to EDTA disodium salt is 50 ml:1 mmol. Adjust the pH to 4.5 with dilute sulfuric acid, heat to 60℃, stir for 2 hours, cool to room temperature, filter the white crystals precipitated, wash with ethanol for 3 times, and vacuum dry to obtain EDTA-Zn pre-chelate.

[0054] The characterization results of the EDTA-Zn pre-chelate prepared in the present embodiment show that the yield is 92%.

[0055] ICP-MS analysis results show that the Zn content is 12.8wt% (theoretical value 13.2%), which conforms to the 1:1 complexing ratio.

[0056] Embodiment 2

[0057] The stripping solution of the present embodiment belongs to the processing technology of semiconductor devices, and relates to the materials used therein,

[0058] The present embodiment provides a preparation method of stripping solution, the steps of which are as follows:

[0059] S1 Mix DMSO with hydroxyethyl ethylenediamine, heat to 40℃ and stir to dissolve. Add EDTA-Zn, PBTCA, ammonium molybdate and deionized water in sequence, and adjust the pH to 8.0.

[0060] S2 Two-stage stirring:

[0061] First stage: 30℃ stirring for 12 minutes; EDTA complexing free metal ions on the surface

[0062] Second stage: temperature raised to 50℃ stirring for 12 minutes; PBTCA deeply complexing lattice defect ions.

[0063] S3 filtered through 0.2μm PTFE filter membrane to obtain homogeneous stripping solution.

[0064] In this embodiment, the amount of each component is: by weight, hydroxyethyl ethylenediamine 9.5 parts, dimethyl sulfoxide (DMSO) 65 parts, EDTA-Zn pre-chelate obtained in Example 1 0.8 parts, PBTCA 0.8 parts, ammonium molybdate 0.6 parts, deionized water: make up to 100 parts.

[0065] Example 3

[0066] The stripping solution of this embodiment belongs to the processing technology of semiconductor devices, and relates to the materials used therein,

[0067] This embodiment provides a preparation method of a stripping solution, and the steps are:

[0068] S1: DMSO and methyldiethanolamine are mixed and heated to 40℃ for stirring and dissolution. EDTA-Zn obtained in Example 1, PBTCA, ammonium molybdate, benzotriazole and deionized water are added in sequence, and the pH is adjusted to 7.8.

[0069] S2: two-stage stirring:

[0070] First stage: 32℃ stirring for 12 minutes; EDTA complexing surface free metal ions

[0071] Second stage: temperature raised to 50℃ stirring for 12 minutes; PBTCA deeply complexing lattice defect ions.

[0072] S3 filtered through 0.2μm PTFE filter membrane to obtain homogeneous stripping solution.

[0073] In this embodiment, the amount of each component is: by weight, methyldiethanolamine 9.5 parts, N-methylpyrrolidone 65 parts, EDTA-Zn pre-chelate obtained in Example 1 0.75 parts, PBTCA 0.75 parts, ammonium molybdate 0.75 parts, benzotriazole 0.25 parts, deionized water: make up to 100 parts.

[0074] Example 4

[0075] The stripping solution of this embodiment belongs to the processing technology of semiconductor devices, and relates to the materials used therein,

[0076] This embodiment provides a preparation method of a stripping solution, and the steps are:

[0077] S1 mix DMSO with hydroxyethyl ethylenediamine, heat to 45℃ and stir to dissolve. Add EDTA-Zn, PBTCA, ammonium molybdate, deionized water in sequence, adjust pH to 8.2;

[0078] S2 two-stage stirring:

[0079] First stage: 40℃ stirring for 15 minutes; EDTA complexing surface free metal ions;

[0080] Second stage: heating to 55℃ stirring for 15 minutes; PBTCA deeply complexing lattice defect ions;

[0081] S3 filter through 0.2μm PTFE filter membrane to obtain homogeneous stripping solution.

[0082] In this embodiment, the amount of each component is: by weight, hydroxyethyl ethylenediamine 9 parts, dimethyl sulfoxide (DMSO) 60 parts, EDTA-Zn pre-chelate obtained in Example 1 0.5 parts, PBTCA 0.5 parts, mercaptobenzothiazole 0.5 parts, deionized water: make up to 100 parts.

[0083] Example 5

[0084] This embodiment provides a test method for the performance of stripping solution,

[0085] Experimental group: stripping solution prepared by the method of Example 2, (containing EDTA-Zn);

[0086] Control group: stripping solution prepared by the method of Example 2, but using equimolar EDTA disodium salt instead of EDTA-Zn. The test results are shown in Table 1.

[0087] Table 1: test results

[0088] Test Index Experimental Group Control Group In Dissolution in IGZO 0.5 nm / min 1.8 nm / min PVX Photoresist Stripping Speed 0.08 at% 0.25 at% 40°C Storage Stability 40°C Storage Stability Precipitation (after 15 days) CuMoNb Corrosion Rate 0.5 nm / min 1.8 nm / min

[0089] Example 6

[0090] This embodiment provides a verification method for the synergistic effect of corrosion inhibitor and EDTA-Zn,

[0091] The stripping solutions of groups A, B, C and D are all prepared by the method of Example 2, the difference

[0092] Lies in:

[0093] Group A: by weight, ammonium molybdate 0.6 parts, EDTA-Zn 0.8 parts;

[0094] Group B: by weight, ammonium molybdate 1.4 parts, EDTA-Zn 0 parts;

[0095] Group C: by weight, ammonium molybdate 0 parts, EDTA-Zn 1.4 parts;

[0096] Group D: by weight, ammonium molybdate 0 parts, EDTA-Zn 0 parts;

[0097] Test method:

[0098] Substrate: CuMoNb alloy sheet (thickness 200 nm, surface roughness Ra < 2 nm).

[0099] The substrate was immersed in the stripping solution (60℃) for 30 minutes, the Cu dissolution amount was detected by ICP-MS, and the surface morphology was observed by SEM. The Cu corrosion rate results are shown in Table 2.

[0100] Table 2: Cu corrosion rate

[0101] Group Corrosion Rate (nm / min) Group A 0.5 Group B 1.2 Group C 1.0 Group D 4.8

[0102] From Table 2, it can be seen that the corrosion rate of Group A is reduced by 58% compared to Group B / C, the single corrosion inhibitor of Group B has limited effect, and Group C lacks a passivation layer of ammonium molybdate. The corrosion rate of the blank group (Group D) is greater than that of Group B and Group C. Comparison shows that there is a synergistic effect between the corrosion inhibitor and EDTA-Zn.

[0103] Example 7

[0104] The stripping solution prepared in Example 2 was used for various materials,

[0105] CuMoNb / Ti stack: SEM after stripping showed no grain boundary corrosion, and the thickness loss of the Ti layer was <1 nm.

[0106] IGZO-TFT array: electrical performance test showed that the threshold voltage shift was <0.1 V (industry requirement <0.3 V).

[0107] Al wiring panel: no pitting, surface roughness (Ra) decreased from 0.8 nm to 0.5 nm.

[0108] Data support:

[0109] XPS analysis: Zn-In / Ga displacement layer was detected on the surface of IGZO (energy shift confirmed ion exchange).

[0110] TOF-SIMS: Mo-O passivation film (thickness <2 nm) exists at the CuMoNb interface.

[0111] Example 8

[0112] The COD (mg / L) of the stripping solution obtained in Examples 2-4 was 1200, 1340, 1198, respectively, the fluorine ion content was not detected, and the biodegradability (28 days) was more than 78%.

[0113] The experimental results of the present application show that pre-chelation makes Zn 2+ Adsorption efficiency is improved by 3 times (not expected by simple combination).

[0114] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, and are not limited thereto; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that the technical solutions recorded in the foregoing embodiments can still be modified, or some or all of the technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. An aqueous peeling solution suitable for various structures, characterized by, It comprises the following components by weight: The organic amine compound is 9-10 parts, the organic solvent is 60-70 parts, the corrosion inhibitor is 0.5-1 part, and the modified EDTA compound is 0.5-1 part; the organic amine compound is hydroxyethyl ethylenediamine, methyldiethanolamine, triethanolamine or diglycolamine; The modified EDTA compound is an EDTA-Zn prechelate, and the preparation method of the EDTA-Zn prechelate comprises the following steps: S11, mixing EDTA and zinc sulfate at a molar ratio of 3-1:1, and reacting at pH 4-5 and 55-60 DEG C for 2-3 hours; S12, filtering after cooling to obtain white crystalline EDTA-Zn prechelate.

2. The aqueous peeling solution for use in a plurality of structures according to claim 1, wherein The aqueous stripping solution also comprises PBTCA.

3. The aqueous peeling solution for use in a plurality of structures according to claim 1, characterized by: The corrosion inhibitor is at least one of ammonium molybdate, uracil, methylbenzotriazole, mercaptobenzothiazole, benzotriazole and modified products thereof.

4. A method for preparing the aqueous peeling solution suitable for various structures according to claim 1, characterized by, It comprises the following steps: S1, mixing the organic solvent with the organic amine compound and heating and stirring; S2, sequentially adding the modified EDTA compound, the corrosion inhibitor and water and stirring; S3, filtering to obtain the stripping solution.

5. The method for preparing an aqueous peeling solution for use in a plurality of structures according to claim 4, characterized in that, The stirring in step S2 is divided into two stages: ​ The first stage is to keep the temperature at 25-40 DEG C and stir for 10-15 minutes; The second stage is to heat to 48-55 DEG C and stir for 10-15 minutes.

6. Application of the aqueous stripping solution suitable for various structures according to claim 1 in the manufacture of semiconductor and display panels.