High-selectivity TiN cleaning solution easy to clean

Abstract

The invention relates to the technical field of semiconductor cleaning, and particularly discloses an easy-to-clean high-selectivity TiN cleaning solution which comprises the following components in percentage by mass: 5-60% of an oxidizing agent, 1-10% of organic alkali, 5-20% of an aprotic solvent, 0.01-0.5% of amino acid, 0.1-10% of ammonium salt, 0.1-5% of a compound inhibitor and the balance of water, and the compound inhibitor comprises alcohol ether and heterocyclic nitride. The oxidizing agent oxidizes TiN into water-soluble HTiO3 <->, the organic base serves as a pH regulator, the ammonium salt improves the etching rate of a TiN layer, the amino acid serves as an oxidizing agent stabilizer, the compound inhibitor is a mixture of alcohol ether (the number of main chain C atoms is larger than or equal to 8, and the number of O atoms is larger than or equal to 3) and heterocyclic nitride (the number of N atoms is larger than or equal to 2), etching of low-dielectric-constant dielectric materials, Cu, Co and W is inhibited by introduction of the compound inhibitor, and most importantly, the compound inhibitor is a mixture of the compound inhibitor and the compound inhibitor. The material is easy to clean, and residues are not left on Cu, Co and W materials. The method can be used for cleaning and removing TiN of a microelectronic device.

Description

Technical Field

[0001] The invention belongs to the technical field of semiconductor cleaning, and in particular relates to an easy-to-clean high-selectivity TiN cleaning solution, which can be used for removing TiN from a microelectronic device. Background Art

[0002] Metals such as Cu and Co have excellent anti-electromigration properties and low resistivity and are widely used in integrated circuit wiring materials. However, the diffusion problem of Cu, Co, etc. in Si-based materials seriously affects the performance of semiconductor devices. Adding a thin layer of TiN with low resistivity and good thermal stability between Cu, Co, etc. and the Si substrate can effectively solve the technical problem of Cu, Co, etc. diffusion, and can also effectively improve their adhesion strength.

[0003] The dual damascene process based on TiN hard mask is widely used below 20 nm node to improve the profile control of vias and trenches. Afterwards, in order to reduce the aspect ratio of the etched structure and facilitate the subsequent barrier layer, Cu seed layer and Cu filling, the TiN hard mask needs to be removed by wet etching process. The wet etching process must effectively remove the TiN hard mask and post-etch residue without affecting the low-k dielectric material and the underlying metal interconnect material.

[0004] At present, a variety of TiN cleaning solutions have been developed. Under harsh oxidative environments, conventional corrosion inhibitors are difficult to effectively protect metal interconnect materials. In addition, the cleaning solutions of these corrosion inhibitors will be adsorbed onto the metal surface and contaminate the underlying Cu or Co metal layer. These contaminants are usually difficult to remove, resulting in an increase in chip scrap rate. Therefore, while cleaning TiN, it is also required to have high selectivity for low-k dielectric materials and metal interconnect materials. Summary of the invention

[0005] The invention provides a highly selective TiN cleaning solution which is easy to clean. The cleaning solution does not damage low-dielectric constant dielectric materials and does not corrode metal interconnection materials, and does not leave residues on Cu, Co and W materials after cleaning.

[0006] The technical solution of the present invention is to provide a highly selective TiN cleaning solution that is easy to clean. The cleaning solution contains the following components by mass percentage: 5-60% oxidant, 1-10% organic base, 5-20% aprotic solvent, 0.01-0.5% amino acid, 0.1-10% ammonium salt, 0.1-5% compound inhibitor, and the balance is water; the compound inhibitor includes alcohol ether and heterocyclic nitride.

[0007] Furthermore, the oxidant is one or more of hydrogen peroxide (H2O2), phosphoric acid (H3PO4), nitric acid (HNO3), persulfate, perborate, ferric salt, benzoyl peroxide, ozone, perchlorate, periodate, permanganate, hypochlorite, peracetic acid, perbenzoic acid and urea peroxide.

[0008] Furthermore, the organic base is one or more of N-methyldiethanolamine, diethanolamine, diisopropanolamine, isopropanolamine (MIPA), N-methylethanolamine, monoethanolamine (MEA), triethanolamine (TEA), tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide (TEAH), tetraethylammonium hydroxide (TEAH) and choline hydroxide.

[0009] Furthermore, the aprotic solvent is one or more of dimethyl sulfoxide (DMSO), 1,3-dimethyl-2-imidazolidinone (DMI), acetonitrile, propylene carbonate, hexamethylphosphoric triamide (HMPA), dimethylacetamide (DMAc), dimethylformamide (DMF) and N-methyl-2-pyrrolidone (NMP).

[0010] Furthermore, the amino acid is one or more of arginine (Arg), glycine, serine, proline, leucine, alanine, aspartic acid, valine and lysine.

[0011] Further, the ammonium salt is one or more of ammonium citrate, triammonium citrate, ammonium acetate, ammonium bromide (NH4Br), ammonium chloride (NH4Cl), ammonium tartrate, ammonium malonate, ammonium adipate, ammonium lactate, dodecyltrimethylammonium bromide (DTAB), hexadecyltrimethylammonium bromide (CTAB), ammonium sulfate, ammonium carbamate, ammonium benzoate, tetraammonium ethylenediaminetetraacetate and ammonium succinate.

[0012] Furthermore, the alcohol ether is diethylene glycol monobutyl ether (DEB), triethylene glycol monoethyl ether, triethylene glycol monobutyl ether, diethylene glycol monohexyl ether, tripropylene glycol methyl ether (TPGME), dipropylene glycol ethyl ether, dipropylene glycol n-propyl ether (DPGPE ), one or more of tripropylene glycol n-propyl ether, dipropylene glycol n-butyl ether, tripropylene glycol n-butyl ether and fatty alcohol polyoxyethylene ether; the heterocyclic nitride is one or more of pyrazole, 4-aminopyrazole, pyrazole-3-carboxylic acid, 2-amino-1,3,4-thiadiazole, imidazole, imidazolidinone, 1H-1,2,3-triazole, 1,2,4-triazole-3-carboxylic acid, 1,2,4-triazole (TAZ), 1-methyl-1,2,4-triazole, benzotriazole (BTA), 5-carboxy-benzotriazole, tetrazole, 1H-tetrazole-5-acetic acid, 5-methyltetrazole, 5-phenyl-1H-tetrazole and 5-amino-1H-tetrazole (ATZ).

[0013] Furthermore, in the compound inhibitor, the number of C atoms in the main chain of the alcohol ether is ≥8, and the number of O atoms is ≥3; the number of N atoms in the heterocyclic nitride is ≥2; and the mass ratio of the alcohol ether to the hybrid nitride is 1:2~10.

[0014] Furthermore, the pH of the cleaning solution is 8-11.

[0015] The invention also relates to the application of the cleaning liquid in cleaning and removing TiN from microelectronic devices.

[0016] The present invention has the following beneficial effects: The cleaning solution provided by the present invention is added with a compound corrosion inhibitor composed of an alcohol ether and a heterocyclic nitride, which can form an alcohol ether-metal-heterocyclic nitride network protective film structure, and can well protect metal materials. The ammonium salt can repair the defects of the protective film, and can also improve and stabilize the etching rate of TiN. In addition, the introduction of the alcohol ether reduces its adsorption energy with the metal and the surface tension of the cleaning solution, and can be rinsed clean by deionized water, and almost no pollutants are left on the metal surface after the cleaning operation is completed. DETAILED DESCRIPTION

[0017] The present invention is described in detail below in conjunction with specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and a specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0018] The TiN cleaning solution provided by the present invention contains at least one oxidant, one organic base, one aprotic solvent, one ammonium salt, one amino acid, one compound inhibitor and deionized water, wherein the compound inhibitor comprises alcohol ether and heterocyclic nitride.

[0019] In certain embodiments, the oxidant is used in an amount of 5 to 60%, more preferably 10% to 50%, and most preferably 20% to 40%. The specific oxidant can be hydrogen peroxide (H2O2), phosphoric acid (H3PO4), nitric acid (HNO3), persulfate, perborate, ferric salt, benzoyl peroxide, ozone, perchlorate, periodate, permanganate, hypochlorite, peracetic acid, perbenzoic acid, urea peroxide and combinations thereof. Wherein H2O2 has a low metal content and is easily available, preferably H2O2. The H2O2 used in the following examples and comparative examples is a 30% H2O2 aqueous solution by mass.

[0020] In some embodiments, the organic base preferably accounts for 1% to 10% of the cleaning solution, more preferably 1% to 8%, and most preferably 3% to 6%. The organic base can be N-methyldiethanolamine, diethanolamine, diisopropanolamine, isopropanolamine (MIPA), N-methylethanolamine, monoethanolamine (MEA), triethanolamine (TEA), tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide (TEAH), tetraethylammonium hydroxide (TEAH), choline hydroxide, and combinations thereof.

[0021] In some embodiments, the ammonium salt preferably accounts for 0.1% to 10% of the cleaning solution, more preferably 0.1% to 5%, and most preferably 1% to 5%. The ammonium salt is ammonium citrate, triammonium citrate, ammonium acetate, ammonium bromide (NH4Br), ammonium chloride (NH4Cl), ammonium tartrate, ammonium malonate, ammonium adipate, ammonium lactate, dodecyltrimethylammonium bromide (DTAB), hexadecyltrimethylammonium bromide (CTAB), ammonium sulfate, ammonium carbamate, ammonium benzoate, tetraammonium ethylenediaminetetraacetate, ammonium succinate, and combinations thereof. The preferred ammonium salt may be a small molecule carboxylic acid polyammonium.

[0022] In some embodiments, the amino acid preferably accounts for 0.0001% to 0.5% of the cleaning solution, more preferably 0.0005% to 0.2%, and most preferably 0.001% to 0.1%. The amino acid is arginine (Arg), glycine, serine, proline, leucine, alanine, aspartic acid, valine, lysine, and combinations thereof; arginine.

[0023] In some embodiments, the aprotic solvent accounts for 5 to 20% of the cleaning solution, more preferably 10 to 20%, and most preferably 15 to 20%. The aprotic solvent is dimethyl sulfoxide (DMSO), 1,3-dimethyl-2-imidazolidinone (DMI), acetonitrile, propylene carbonate, hexamethylphosphoric triamide (HMPA), dimethylacetamide (DMAc), dimethylformamide (DMF), N-methyl-2-pyrrolidone (NMP) and combinations thereof.

[0024] The alcohol ether in the compound inhibitor preferably accounts for 0.1% to 2% of the cleaning solution, more preferably 0.1% to 1%, and most preferably 0.1% to 0.5%. The heterocyclic nitrogen compound in the compound inhibitor preferably accounts for 0.5% to 5% of the cleaning solution, more preferably 0.5% to 2%, and most preferably 0.8% to 2%.

[0025] The alcohol ether (main chain C atoms ≥ 8, O atoms ≥ 3) in the compound inhibitor is diethylene glycol monobutyl ether (DEB), triethylene glycol monoethyl ether, triethylene glycol monobutyl ether, diethylene glycol monohexyl ether, tripropylene glycol methyl ether (TPGME), dipropylene glycol ethyl ether, dipropylene glycol n-propyl ether (DPGPE), tripropylene glycol n-propyl ether, dipropylene glycol n-butyl ether, tripropylene glycol n-butyl ether, fatty alcohol polyoxyethylene ether and combinations thereof. Preferred alcohol ethers can be selected from long-chain alcohol ethers, such as fatty alcohol polyoxyethylene ether. The heterocyclic nitrogen compound (N atom ≥ 2) is pyrazole, 4-aminopyrazole, pyrazole-3-carboxylic acid, 2-amino-1,3,4-thiadiazole, imidazole, imidazolidinone, 1H-1,2,3-triazole, 1,2,4-triazole-3-carboxylic acid, 1,2,4-triazole (TAZ), 1-methyl-1,2,4-triazole, benzotriazole (BTA), 5-carboxyl-benzotriazole, tetrazole, 1H-tetrazolyl-5-acetic acid, 5-methyltetrazole, 5-phenyl-1H-tetrazole, 5-amino-1H-tetrazole (ATZ) and combinations thereof. Preferred heterocyclic nitrogen compounds may be selected from heterocyclic polynitrogen compounds.

[0026] The cleaning solution prepared by the present invention has a pH of 8 to 11, more preferably a pH of about 7 to 10, and most preferably a pH of 8 to 9.

[0027] The following examples and comparative examples are provided to further illustrate the cleaning solution of the present invention. See Table 1 for details. Unless otherwise indicated, all percentages are by weight.

[0028] The TiN cleaning solution of the present invention is composed of the components described in Table 1, and the balance is deionized water. The compound corrosion inhibitor is prepared first, and the preparation order is deionized water, alcohol ether, and heterocyclic nitride. After mixing evenly, the TiN cleaning solution is prepared, and deionized water is added first, then a non-protonic solvent is added, then an organic base is added, then an amino acid is added, then an ammonium salt is added, then the compound corrosion inhibitor is added, and finally hydrogen peroxide is added. After all components are added, the solution is stirred evenly using a glass rod.

[0029] Table 1

[0030] The preparation of the cleaning solution in the above embodiments and comparative examples is specifically to prepare the compound corrosion inhibitor first, and the preparation order is deionized water, alcohol ether, and heterocyclic nitride. After mixing evenly, the TiN cleaning solution is prepared, and deionized water is added first, and then the aprotic solvent, organic base, amino acid, ammonium salt and compound corrosion inhibitor are added in sequence, and finally hydrogen peroxide is added. After all components are added, the solution is stirred evenly using a glass rod.

[0031] The cleaning solutions obtained in the above examples and comparative examples were used in TiN cleaning tests.

[0032] 1) TiN, Cu, Co, W and TEOS etching rates After chemically treating the TiN film layer at 50°C for 2 minutes, the TiN etching rate evaluation was implemented. After chemically treating the Cu, Co, and W film layers at 50°C for 10 minutes, the Cu, Co, and W etching rate evaluations were implemented. After 30 minutes, the TEOS etching rate evaluation was implemented. The thickness of TiN, Cu, Co, and W was measured using Four Dimensions Four Point Probe Meter333A, and the impedance of the film was related to the film thickness remaining after contact with the composition of the present invention. The TEOS thickness was measured using the Auto SE Spectroscopic Ellipsometer from HORIBA JOBIN YVON. The etching rate was calculated as the thickness change (before and after chemical treatment) divided by the chemical treatment time.

[0033] 2) Residual contaminants on metal substrate The residual contaminants were evaluated by ultra-depth-of-field microscopy and SEM, where A represents a large amount of residue, B represents a relatively large amount of residue, C represents a small amount of residue, and D represents complete removal.

[0034] Specific test data are shown in Table 2.

[0035] Table 2

[0036] According to the experimental results of the above embodiments, it can be seen that the TiN cleaning solution provided by the present invention can quickly remove TiN without leaving any residue on the metal layer, and at the same time inhibits the etching of Cu, Co, W, and TEOS, and has high selectivity for TiN.

[0037] The above embodiments describe the preferred implementation of the present invention, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A highly selective TiN cleaning solution that is easy to clean, characterized in that: The cleaning solution contains the following components in percentage by mass: 5-60% of an oxidant, 1-10% of an organic base, 5-20% of an aprotic solvent, 0.01-0.5% of an amino acid, 0.1-10% of an ammonium salt, 0.1-5% of a compound inhibitor, and the remainder is water; the compound inhibitor comprises alcohol ether and a heterocyclic nitride.

2. The cleaning liquid according to claim 1, characterized in that: The oxidant is one or more of hydrogen peroxide, phosphoric acid, nitric acid, persulfate, perborate, ferric salt, benzoyl peroxide, ozone, perchlorate, periodate, permanganate, hypochlorite, peracetic acid, perbenzoic acid and urea peroxide.

3. The cleaning solution according to claim 1, characterized in that: The organic base is one or more of N-methyldiethanolamine, diethanolamine, diisopropanolamine, isopropanolamine, N-methylethanolamine, monoethanolamine, triethanolamine, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetraethylammonium hydroxide and choline hydroxide.

4. The cleaning liquid according to claim 1, characterized in that: The aprotic solvent is one or more of dimethyl sulfoxide, 1,3-dimethyl-2-imidazolidinone, acetonitrile, propylene carbonate, hexamethylphosphoric triamide, dimethylacetamide, dimethylformamide and N-methyl-2-pyrrolidone.

5. The cleaning liquid according to claim 1, characterized in that: The amino acid is one or more of arginine, glycine, serine, proline, leucine, alanine, aspartic acid, valine and lysine.

6. The cleaning liquid according to claim 1, characterized in that: The ammonium salt is one or more of ammonium citrate, triammonium citrate, ammonium acetate, ammonium bromide, ammonium chloride, ammonium tartrate, ammonium malonate, ammonium adipate, ammonium lactate, dodecyltrimethylammonium bromide, hexadecyltrimethylammonium bromide, ammonium sulfate, ammonium carbamate, ammonium benzoate, tetraammonium ethylenediaminetetraacetate and ammonium succinate.

7. The cleaning liquid according to claim 1, characterized in that: The alcohol ether is one or more of diethylene glycol monobutyl ether, triethylene glycol monoethyl ether, triethylene glycol monobutyl ether, diethylene glycol monohexyl ether, tripropylene glycol methyl ether, dipropylene glycol ethyl ether, dipropylene glycol n-propyl ether, tripropylene glycol n-propyl ether, dipropylene glycol n-butyl ether, tripropylene glycol n-butyl ether and fatty alcohol polyoxyethylene ether; the heterocyclic nitride is pyrazole, 4-aminopyrazole, pyrazole-3-carboxylic acid, 2-amino-1,3,4 -thiadiazole, imidazole, imidazolidinone, 1H-1,2,3-triazole, 1,2,4-triazole-3-carboxylic acid, 1,2,4-triazole, 1-methyl-1,2,4-triazole, benzotriazole, 5-carboxy-benzotriazole, tetrazole, 1H-tetrazole-5-acetic acid, 5-methyltetrazole, 5-phenyl-1H-tetrazole and 5-amino-1H-tetrazole. One or more.

8. The cleaning solution according to any one of claims 1 to 7, characterized in that: In the compound inhibitor, the number of carbon atoms in the main chain of the alcohol ether is ≥8, the number of oxygen atoms is ≥3; the number of nitrogen atoms in the heterocyclic nitride is ≥2; and the mass ratio of the alcohol ether to the heterocyclic nitride is 1:2-10.

9. The cleaning solution according to any one of claims 1 to 7, characterized in that: The pH of the cleaning solution is 8~11.

10. Use of the cleaning solution according to any one of claims 1 to 9 in cleaning and removing TiN from microelectronic devices.

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