Cleaning solution

Abstract

The present invention provides a cleaning solution, comprising: an organic solvent, an organic base, a metal corrosion inhibitor, a chelating agent, an oxidant, and water. In the present invention, by using the cleaning solution containing the organic base, metal corrosion inhibitor, chelating agent and oxidant in an appropriate ratio, a titanium nitride hard mask and photoresist etching residues can be removed while corrosion of copper, cobalt, and non-metallic materials (low-k dielectric materials) is inhibited, thereby prolonging the service life of the cleaning solution.

Description

A cleaning fluid Technical Field

[0001] This invention relates to the field of semiconductor cleaning solutions, and more particularly to a cleaning solution. Background Technology

[0002] Copper is a stable metal that does not produce volatile byproducts when reacting with etching gases. Therefore, unlike aluminum, copper cannot be directly etched using dry etching processes to form metal interconnect patterns. In 1997, IBM developed the damask process. This process uses photolithography and dry etching to form trenches for metal interconnect patterns on a dielectric material layer, depositing a metal barrier layer, a copper seed layer, and metallic copper. Excess metal is then removed using CMP (Chemical Metallurgy Processing) to form the desired metal interconnects. Multilayer copper interconnect processes generally require a dual damask process that simultaneously forms interconnect trenches and interconnect vias.

[0003] In integrated circuit (IC) manufacturing, the copper double damask process is becoming increasingly widespread, and high-speed rotating microcontroller cleaning has become the mainstream cleaning method. As interconnect feature sizes further shrink to 28nm and below, plasma damage during processes such as resist removal can severely impact the mechanical and physicochemical properties of low-k materials, causing localized increases in the k-value within the integrated structure and weakening the advantages of low-k dielectric materials. Furthermore, due to the low surface energy and cross-linking properties of etching residues, as well as variations in the physical and chemical properties of the residue components, coupled with compatibility issues between the cleaning solution and the equipment's film materials and structure, finding a low-surface-tension cleaning solution that can effectively remove plasma etching residues while protecting low-k dielectric materials, non-metallic materials, and metallic materials is becoming increasingly challenging.

[0004] Currently, reports on semiconductor cleaning solutions in the integrated circuit field are mainly from overseas. Advanced Technology Materials, Inc. of the United States disclosed in patent CN101366107B an aqueous oxide composition for highly selectively removing titanium-containing (TiN) hard mask materials from microelectronic device substrates, as well as its preparation and application method. Substrate materials mainly include low-k dielectric materials such as organic polymers, organosilicon glass (OSG), carbon-doped oxide (CDO) glass, tetraethyl orthosilicate (TEOS), and FSG, while the main metallic materials are copper and cobalt. This cleaning solution composition primarily uses H₂O₂ as an oxidant, amines such as primary, secondary, and tertiary amines and amine-N-oxides as oxidant stabilizers, at least one organic acid as a metal chelating agent, at least one azole as a metal corrosion inhibitor, and is combined with a buffer, an organic co-solvent, and water. Under conditions of pH 3–9 and a temperature of 30–50°C, it selectively and effectively removes titanium-containing plasma etching residues, sidewall polymerization residues, copper-containing via residues, and / or titanium-containing hard mask layers from microelectronic devices. This cleaning solution can remain stable for 6–24 hours, achieving efficient cleaning of residual materials from microelectronic devices without damaging dielectric materials and metal interconnect materials.

[0005] In a recent report, Versum Material Co., Ltd. disclosed a composition for removing TiN hard masks from electronic circuit devices in patent US2020035485A1. The composition primarily uses hydrogen peroxide as an oxidant, macromolecular organic acids as hydrogen peroxide stabilizers, azoles and polyols as metal corrosion inhibitors, quaternary ammonium hydroxides and ammonium salts as etchants, and water as a solvent. Optional fluorides are added to ensure cleaning power. This method selectively removes titanium nitride and residues from plasma etching processes in an environment with a pH greater than 5.5, while effectively protecting secondary materials such as Cu, Co, and low-k dielectric materials. In wafer or device processing, copper loss after removal with dilute hydrofluoric acid is affected by the thickness of the copper oxide layer. This invention mentions that corrosion inhibitors containing amino groups can provide better copper oxide thickness performance. Summary of the Invention

[0006] In order to overcome the above-mentioned technical defects, the purpose of this invention is to provide a cleaning solution that uses a cleaning solution with a reasonable ratio of organic base, metal corrosion inhibitor, chelating agent and oxidant. This cleaning solution can remove the etching residue of titanium nitride hard mask and photoresist while inhibiting the corrosion of copper, cobalt and non-metals (low-k dielectric materials), and can also extend the service life of the cleaning solution.

[0007] This invention discloses a cleaning solution comprising: an organic solvent, an organic base, a metal corrosion inhibitor, a chelating agent, an oxidizing agent, and water.

[0008] Optionally, the metal corrosion inhibitor is selected from benzotriazole, methylbenzotriazole, 5-carboxybenzotriazole, 5-phenyltetrazole, 1,2,4-triazole, 5-aminotetrazole, 3-amino-1H-1,2,4-triazole, 3,5-diamino-1,2,4-triazole, tolyltriazole, 3-amino-5-mercapto-1,2,4-triazole, 1-amino-1,2,4-triazole, 1-amino-1,2,3-triazole, 1-amino-5-methyl-1,2,3-triazole, 1,2,3-triazole, TT-LYK(2,2'-[[(methyl-1H-benzotriazole-1-yl)methyl]imino]diethanol). One or more of the following: 3-mercapto-1,2,4-triazole, 3-isopropyl-1,2,4-triazole, naphthalenetriazole, 1H-tetrazole-5-acetic acid, 1-phenyl-2-tetrazole-5-thione, 4-methyl-2-phenylimidazolium, 2-mercaptothiazoline, 2,4-diamino-6-methyl-1,3,5-triazine, thiazole, imidazole, benzylhydroxylamine, hydroxylamine, benzimidazole, methyltetrazole, 1,5-pentamethylenetetrazole, 1-phenyl-5-mercaptotetrazole, benzothiazole, indazole, adenine, guanine, thymine, oxalic acid, phenothiazine, 1-methylpyrazole, methyl 2-hydroxyisobutyrate, 6-mercaptopurine, phosphoric acid, and benzoic acid.

[0009] Optionally, the concentration of the metal corrosion inhibitor is 0.01 wt% to 5 wt%.

[0010] Optionally, the chelating agent is selected from one or more of the following: lauric acid, benzoic acid, tartaric acid, ethylenediaminetetraacetic acid, iminodiacetic acid, aspartic acid, aminotriacetic acid, salicylic acid, glycine, L-phenylalanine, malonic acid, succinic acid, 2,3-pyridinedicarboxylic acid, L-tyrosine, cinnamic acid, histidine, 1,2-cyclohexanediaminetetraacetic acid, 2,2'-azaalkyldimethyldiacetic acid, ethylenediaminetetraacetic acid, 2-(2-hydroxyphenyl)-benzoazole, 2-(2-hydroxyphenyl)-benzothiazole, pyridine, 3-methoxypyridine, 2-methylpyridine, dimethylpyridine, piperidine, piperazine, pyrrole, pyrimidine, pyrazine, pyridazine, quinoline, indole, and 1-methylimidazole.

[0011] Optionally, the concentration of the chelating agent is 0.01 wt% to 5 wt%.

[0012] Optionally, the organic solvent is selected from one or more of ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monobutyl ether, dipropylene glycol monoethyl ether, dipropylene glycol methyl ether, 1,3-propanediol monoethyl ether, methoxy-1-propanol, propylene glycol propyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monomethyl ether, triethylene glycol monomethyl ether, dimethyl sulfoxide, dimethyl sulfone, and sulfolane.

[0013] Optionally, the concentration of the organic solvent is 1 wt% to 50 wt%.

[0014] Optionally, the organic base is selected from one or more of quaternary ammonium hydroxides, organic amines, or organic alcohol amines.

[0015] Optionally, the organic base is selected from one or more of tetramethylammonium hydroxide, tetraethylammonium hydroxide, trimethylphenylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, benzyltrimethylammonium hydroxide, benzyltriethylammonium hydroxide, choline, ammonium hydroxide, ethanolamine, triethanolamine, diethylene glycolamine, and urea.

[0016] Optionally, the concentration of the organic base is 0.01 wt% to 5 wt%.

[0017] Optionally, the oxidant is selected from one or more of H2O2, N-methylmorpholine oxide, benzoyl peroxide, urea peroxide, peracetic acid, peroxybenzoic acid, and alloxan.

[0018] Optionally, the oxidant is H2O2.

[0019] Optionally, the concentration of the oxidant is 0.1 wt% to 5 wt%.

[0020] Optionally, the pH value of the cleaning solution is 4 to 9.

[0021] Compared with existing technologies, the above technical solution has the following advantages:

[0022] 1. The cleaning solution in this invention can effectively reduce the residual organic matter on the surface of copper or cobalt, efficiently remove the etching residue of titanium nitride hard mask and photoresist, and exhibits a low corrosion rate for copper and cobalt, non-metallic materials and Low-k dielectric materials.

[0023] 2. This invention solves the problems of short service life and high cost of cleaning solutions used in copper damascus sizing processes in existing technologies. The technical solution provided in this invention improves the service life of the cleaning solution, enabling it to be recycled for 48 hours and effectively reducing the residue of organic matter on the copper or cobalt surface.

[0024] 3. The cleaning fluid provided by this invention has good application prospects, especially in the dual damascene process of integrated circuit technology nodes of 28nm and below. Detailed Implementation

[0025] The advantages of the present invention are further illustrated below through specific embodiments, but the scope of protection of the present invention is not limited to the following embodiments.

[0026] Prepare the cleaning solutions for Examples 1-25 and Comparative Examples 1-5 according to the components and their contents shown in Table 1. Mix all components thoroughly. Pour organic solvent and water into a reaction vessel, then add chelating agent, corrosion inhibitor, and oxidant. Stir thoroughly at room temperature until homogeneous. Water is the balance and is not shown in Table 1.

[0027] Table 1. Components and their contents in Examples 1-25 and Comparative Examples 1-5

[0028] Performance tests were conducted on selected embodiments and comparative examples 1-5, and the test results are shown in Table 2.

[0029] Etching rate of titanium nitride The cleaning solution was placed in a reactor and heated to 59°C. A titanium nitride film was then placed in the reactor and etched for 10 minutes. The etching rate was calculated by measuring the thickness change before and after etching using a four-probe method.

[0030] Etching rate of low-k materials The cleaning solution was placed in a reactor and heated to 59°C. The low BDⅠ film was then placed in the reactor and etched for 10 min. The etching rate was calculated by measuring the thickness change before and after etching using an ellipsometry.

[0031] Etching rate of cobalt The cleaning solution was placed in a reactor and heated to 59°C. The cobalt film was then placed in the reactor and etched for 10 minutes. The etching rate was calculated by measuring the change in resistance before and after etching using a four-probe method and converting it into film thickness.

[0032] Etching rate of copper The cleaning solution was placed in a reactor and heated to 59°C. The copper film was then placed in the reactor and etched for 10 minutes. The etching rate was calculated by measuring the change in resistance before and after etching using a four-probe method and converting it into film thickness.

[0033] Table 2 Test results of Example 25 and Comparative Examples 1-5

[0034] Specifically, comparing Comparative Example 1 with Example 25 shows that, under the same conditions (pH control during solution preparation is consistent with Example 25; the final solution in Comparative Example 1 shows pH change caused by the removal of ammonium hydroxide), adding an organic base can significantly increase the etching rate of titanium nitride. Comparative Example 2, compared with Example 25, shows that adding methylbenzotriazole, a metal corrosion inhibitor, to the cleaning solution provides excellent protection for copper and cobalt.

[0035] Comparing Comparative Example 3 with Example 25, it was shown that under the same conditions (pH control during solution preparation was consistent with Example 25; the pH change in the final solution of Comparative Example 3 was caused by the removal of nitric acid), without the addition of a chelating agent, there was significant corrosion of cobalt. Comparative Examples 4 and 5, compared with Example 25, showed that the oxidant can control the etching rate of titanium nitride; the higher the oxidant content, the higher the etching rate of titanium nitride. However, excessive hydrogen peroxide addition can corrode copper and cobalt.

[0036] In summary, the technical solution provided by this invention, which prepares a semiconductor device cleaning solution by rationally proportioning organic base, oxidant, chelating agent, and corrosion inhibitor in the composition, can be recycled for 48 hours to effectively reduce the residual organic matter on the surface of copper or cobalt, efficiently remove titanium nitride hard mask and photoresist etching residues, and exhibits a low corrosion rate on copper and cobalt, non-metallic materials, and Low-k dielectric materials during high-speed rotating microcontroller cleaning. This improves the cleaning solution's lifespan, reduces cleaning costs, and has good application prospects in high-end semiconductor cleaning fields such as integrated circuit technology nodes of 28nm and below.

[0037] It should be noted that the embodiments of the present invention have better implementability and are not intended to limit the present invention in any way. Any person skilled in the art may use the above-disclosed technical content to change or modify it into equivalent effective embodiments. However, any modifications or equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A cleaning solution, characterized in that, include: Organic solvents, organic bases, metal corrosion inhibitors, chelating agents, oxidizing agents, and water.

2. The cleaning solution as described in claim 1, characterized in that, The metal corrosion inhibitor is selected from benzotriazole, methylbenzotriazole, 5-carboxybenzotriazole, 5-phenyltetrazole, 1,2,4-triazole, 5-aminotetrazole, 3-amino-1H-1,2,4-triazole, 3,5-diamino-1,2,4-triazole, tolyltriazole, 3-amino-5-mercapto-1,2,4-triazole, 1-amino-1,2,4-triazole, 1-amino-1,2,3-triazole, 1-amino-5-methyl-1,2,3-triazole, 1,2,3-triazole, TT-LYK (2,2'-[[(methyl-1H-benzotriazole-1-yl)methyl]imino]diethanol), 3 One or more of the following: 1-mercapto-1,2,4-triazole, 3-isopropyl-1,2,4-triazole, naphthalenetriazole, 1H-tetrazole-5-acetic acid, 1-phenyl-2-tetrazolin-5-thione, 4-methyl-2-phenylimidazolium, 2-mercaptothiazoline, 2,4-diamino-6-methyl-1,3,5-triazine, thiazole, imidazole, benzylhydroxylamine, hydroxylamine, benzimidazole, methyltetrazole, 1,5-pentamethylenetetrazole, 1-phenyl-5-mercaptotetrazole, benzothiazole, indazole, adenine, guanine, thymine, oxalic acid, phenothiazine, 1-methylpyrazole, methyl 2-hydroxyisobutyrate, 6-mercaptopurine, phosphoric acid, and benzoic acid.

3. The cleaning solution as described in claim 2, characterized in that, The concentration of the metal corrosion inhibitor is 0.01wt%-5wt%.

4. The cleaning solution as described in claim 1, characterized in that, The chelating agent is selected from one or more of the following: lauric acid, benzoic acid, tartaric acid, ethylenediaminetetraacetic acid, iminodiacetic acid, aspartic acid, aminotriacetic acid, salicylic acid, glycine, L-phenylalanine, malonic acid, succinic acid, 2,3-pyridinedicarboxylic acid, L-tyrosine, cinnamic acid, histidine, 1,2-cyclohexanediaminetetraacetic acid, 2,2'-azaalkyldimethyldiacetic acid, ethylenediaminetetraacetic acid, 2-(2-hydroxyphenyl)-benzoazole, 2-(2-hydroxyphenyl)-benzothiazole, pyridine, 3-methoxypyridine, 2-methylpyridine, dimethylpyridine, piperidine, piperazine, pyrrole, pyrimidine, pyrazine, pyridazine, quinoline, indole, and 1-methylimidazole.

5. The cleaning solution as described in claim 4, characterized in that, The concentration of the chelating agent is 0.01wt%-5wt%.

6. The cleaning solution as described in claim 1, characterized in that, The organic solvent is selected from one or more of ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monobutyl ether, dipropylene glycol monoethyl ether, dipropylene glycol methyl ether, 1,3-propanediol monoethyl ether, methoxy-1-propanol, propylene glycol propyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monomethyl ether, triethylene glycol monomethyl ether, dimethyl sulfoxide, dimethyl sulfone, and sulfolane.

7. The cleaning solution as described in claim 6, characterized in that, The concentration of the organic solvent is 1 wt% to 50 wt%.

8. The cleaning solution as described in claim 1, characterized in that, The organic base is selected from one or more of quaternary ammonium hydroxides, organic amines, or organic alcohol amines.

9. The cleaning solution as described in claim 8, characterized in that, The organic base is selected from one or more of tetramethylammonium hydroxide, tetraethylammonium hydroxide, trimethylphenylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, benzyltrimethylammonium hydroxide, benzyltriethylammonium hydroxide, choline, ammonium hydroxide, ethanolamine, triethanolamine, diethylene glycolamine, and urea.

10. The cleaning solution as described in claim 9, characterized in that, The concentration of the organic base is 0.01wt%-5wt%.

11. The cleaning solution as described in claim 1, characterized in that, The oxidant is selected from one or more of H2O2, N-methylmorpholine oxide, benzoyl peroxide, urea peroxide, peracetic acid, peroxybenzoic acid, and alloxan.

12. The cleaning solution as described in claim 11, characterized in that, The oxidant is H2O2.

13. The cleaning solution as described in claim 12, characterized in that, The concentration of the oxidant is 0.1 wt% to 5 wt%.

14. The cleaning solution as described in claim 1, characterized in that, The pH value of the cleaning solution is 4 to 9.

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