Etching compositions and their uses

Abstract

The present invention provides an etching composition and its applications. The etching composition comprises hydroxylamine, a surfactant, a metal corrosion inhibitor, an amine-based pH adjuster, an organic acid, and water. The etching composition of the present invention can be used for cleaning in cobalt layer processes of 7 nm or more, and has excellent cleaning ability against residual polymers, metal oxides, and fluorides after plasma ashing, while also having good compatibility with TiN and Low-K materials and having a wide process window.

Description

Technical Field

[0001] The present invention relates to the field of chemical etching, and particularly to etching compositions and their uses.

Background Art

[0002] As the characteristic dimensions of IC chips continue to shrink and the integration scale rapidly expands, Moore's Law is gradually approaching its limit. In recent years, with the mass production of EUV exposure equipment, the 7nm process is gradually maturing. However, when copper is used as the wiring material, drawbacks such as insufficient conductivity begin to emerge, and the manufacturing process technology is facing bottlenecks at the 10nm and 7nm nodes. Therefore, in some layers of processes above 7nm, it has become a trend to adopt cobalt instead of copper. As a result, it has become possible to continue Moore's Law. Therefore, an etching composition for the cobalt process is urgently required.

Summary of the Invention

[0003] The present invention provides an etching composition containing hydroxylamine, a surfactant, a metal corrosion inhibitor, an amine-based pH adjuster, an organic acid, and water, which can be used for cleaning cobalt layer processes above 7nm and has good cleaning ability for polymer residues, metal oxides, and fluorides after plasma ashing.

[0004] Preferably, the content of the hydroxylamine is 0.5% to 10%.

[0005] Preferably, the content of the surfactant is 0.001% to 10%.

[0006] Preferably, the surfactant is ethylene glycol monobutyl ether, ethylene glycol glycidyl ether, poly(ethylene glycol-propylene glycol) monobutyl ether, diethylene glycol dimethyl ether, propylene glycol phenyl ether, propylene glycol methyl ether, dodecylamine polyoxyethylene ether, polyethylene glycol, polyethylene glycol-propylene glycol copolymer, vinylpyrrolidone-vinyl acetate copolymer, n-hexanol, 1,2-pentanediol, 1,2-propanediol It is one or more selected from ol, 1,3-propanediol, benzyl alcohol, dioxane, ethanol, n-propanol, isopropanol, n-butanol, SUPERWET-320, SUPERWET-340, SUPERWET-360, SURFYNOL420, SURFYNOL440, coconut fatty acid diethanolamide, dodecyltrimethylammonium chloride, myristyltrimethylammonium chloride, benzalkonium chloride, cetyltrimethylammonium bromide, and tetraheptylammonium bromide.

[0007] Preferably, the content of the metal corrosion inhibitor is 0.1% to 5%.

[0008] Preferably, the metal corrosion inhibitor is one or more selected from pyrazole, 1-methylpyrazole, 3,5-dimethylpyrazole, pyrazine, benzotriazole, methylbenzotriazole, 1H-benzotriazolemethanol, 1,2,4-triazole-3-carboxylate methyl, 5-benzyl-1H-tetrazol, 1-phenyl-5-mercaptotetrazol, 5-benzylthio-1H-tetrazol, 5-methyltetrazol, 2-mercaptothiadiazole, methimazole, mercaptoimidazole, and 3-mercapto-4-methyl-4H-1,2,4-triazole.

[0009] Preferably, the content of the amine-based pH adjuster is 0.05% to 3%.

[0010] Preferably, the amine-based pH adjuster is one or more selected from diethylene glycolamine, ethanolamine, ethylenediamine, diethanolamine, diethylenetriamine, triethylenetetramine, hydroxyethylethylenediamine, N-methylethanolamine, 3-amino-1-propanol, isopropanolamine, diisopropanolamine, triisopropanolamine, and 1,8-diazabicyclo[5.4.0]undeca-7-ene.

[0011] Preferably, the content of the organic acid is 0.05% to 5%.

[0012] The aforementioned organic acid is a carboxylic acid having a nitrogen atom or an oxygen atom at the α-position.

[0013] Preferably, the organic acid is one or more selected from glycolic acid, lactic acid, tonsillic acid, malic acid, citric acid, tartaric acid, gluconic acid, hydroxymalonic acid, pyridine-2-carboxylic acid, 2,3-pyridinedicarboxylic acid, 2,6-pyridinedicarboxylic acid, 1H-1,2,4-triazole-3-carboxylic acid, pyrazole-3-carboxylic acid, glycine, alanine, valine, leucine, isoleucine, methionine, proline, tryptophan, serine, tyrosine, cysteine, phenylalanine, asparagine, glutamine, threonine, aspartic acid, glutamic acid, lysine, arginine, histidine, and pyrrolidine.

[0014] In another aspect of the present invention, the etching composition described in any one of claims 1 to 11 is provided for use in cleaning in a cobalt layer process of 7 nm or more.

[0015] The etching composition of the present invention can be used for cleaning in cobalt layer processes of 7 nm or more, and has excellent cleaning ability against residual polymers, metal oxides, and fluorides after plasma ashing, while also having good compatibility with TiN and Low-K materials, and furthermore, it has a wide process window and good future application potential. [Modes for carrying out the invention]

[0016] The advantages of the present invention will be further explained below with reference to specific examples. Etching compositions for Examples 1 to 10 were prepared according to the composition ratios of each component and their respective contents listed in Table 1. Here, water is the remainder. [Table 1]

[0017] To evaluate the interchangeability of the etching composition with various materials, the etching rates of metallic Co, TiN, and nonmetallic oxide and SiN were measured. The metal etching rate test method was as follows: Blanket wafers of Co and TiN were diced into 5cm x 5cm pieces, placed in a single-substrate rotary cleaning apparatus, and processed under the following conditions: processing time 3 to 20 minutes (preferred time 10 minutes), rotation speed 200 to 900 rpm (preferred rotation speed 600 rpm), and temperature 25 to 70°C (preferred temperature 50°C). After processing, the substrates were removed, rinsed with ultrapure water, and dried with high-purity nitrogen gas.

[0018] The etching rate measurement method is as follows: 1) The resistance value (R1) of an untreated metal blanket wafer measuring 5 cm x 5 cm is measured using a metal thin film thickness measuring device. 2) The 5cm x 5cm untreated metal blanket wafer is placed in a single-substrate rotary cleaning device and processed. 3) After processing, the metal blanket wafer is removed, rinsed with deionized water, dried with high-purity nitrogen gas, and the resistance value (R2) is measured again using a metal thin film thickness measuring device. 4) Input the resistance change and processing time into a dedicated analysis algorithm and calculate the etching rate using the following formula:

number

[0019] The method for measuring the etching rate of non-metallic materials (SiN, Oxide) is as follows: 1) Use an ellipsometer to measure the first thickness D1 of the non-metallic material layer (AlN) of an untreated non-metallic blanket wafer of 5 cm × 5 cm. 2) Install the 5 cm × 5 cm non-metallic blanket wafer in a single substrate rotation cleaning device, and perform a cleaning process under the conditions of a rotation speed of 600 rpm and a processing time of 10 minutes. 3) Take out the processed wafer, dry it with high-purity nitrogen gas after passing through a deionized water rinsing process, and then measure the second thickness D2 with the same ellipsometer. 4) Input the film thickness change amount and the processing time into a dedicated analysis algorithm, and calculate the etching rate according to the following calculation formula:

Equation

[0020] Here, D1 and D2 respectively represent the first thickness and the second thickness of the non-metallic blanket wafer, and T represents the processing time.

[0021] The specific test results are shown in Table 2.

Table 2

[0022] Based on the above test results, it was confirmed that the etching compositions of Examples 1 to 10 have good compatibility with Co, TiN, SiN, and oxides under different temperature, rotation speed, and processing time conditions, and have a low etching rate.

[0023] According to the components and corresponding contents described in Table 3, the etching compositions of Examples 11 to 14 and Comparative Examples 1 to 3 were prepared. [Table 3]

[0024] To further evaluate the compatibility of the aforementioned compositions with materials, the present invention employs the following technical means: measuring the etching rates of metallic Co, TiN, and nonmetallic oxide and SiN. The method for measuring the metal etching rates is as follows: Blanket wafers of Co and TiN were selected, diced to 5 cm × 5 cm, and then placed in a single-substrate rotary cleaning apparatus. Processing was carried out under the following conditions: processing time of 3 to 20 minutes (10 minutes selected in this test), rotation speed of 200 to 900 rpm (set to 600 rpm), and temperature of 25 to 70°C (set to 50°C). After processing, the substrates were removed, rinsed with ultrapure water, and dried with high-purity nitrogen gas.

[0025] The etching rate measurement method is as follows: 1) The resistance value (R1) of an untreated metal blanket wafer measuring 5 cm x 5 cm is measured using a metal thin film thickness measuring device. 2) The 5cm x 5cm untreated metal blanket wafer is placed in a single-substrate rotary cleaning device and processed. 3) After processing, the metal blanket wafer is removed, rinsed with deionized water, dried with high-purity nitrogen gas, and the resistance value (R2) is measured again using a metal thin film thickness measuring device. 4) Input the resistance change and processing time into a dedicated analysis algorithm and calculate the etching rate using the following formula:

number

[0026] R1 and R2 represent the resistance values ​​of the metal blanket wafer, and T represents the processing time of the single-substrate rotary cleaning device. K is a constant that differs depending on the metal material. The unit of metal etching rate is Å / min.

[0027] The etching rate measurement method for nonmetallic materials (SiN, Oxide) is as follows: 1) The first thickness D1 of the nonmetallic material layer (AlN) of a 5cm × 5cm untreated nonmetallic blanket wafer is measured using an ellipsometer. 2) The 5cm x 5cm non-metallic blanket wafer is placed in a single-substrate rotary cleaning device, and the cleaning process is performed under the conditions of a rotation speed of 600 rpm and a processing time of 10 minutes. 3) After processing, the wafer is removed, rinsed with deionized water, dried with high-purity nitrogen gas, and then the second thickness D2 is measured using the same ellipsometer. 4) Input the above film thickness change and processing time into a dedicated analysis algorithm and calculate the etching rate using the following formula:

number

[0028] D1 and D2 represent the first and second thicknesses of the non-metallic blanket wafer, respectively, and T represents the processing time. Specific test results are shown in Table 4. [Table 4]

[0029] As is clear from Examples 11, 12 and Proportional Reaction 1 in Table 4, it was confirmed that 5-benzylthio-1H-tetrazole, a metal corrosion inhibitor, not only significantly reduces the etching rate of Co but also prevents the corrosion of TiN to some extent. As shown in Examples 11, 13 and Proportional Reaction 2, amine-based pH adjusters exert an etching rate reduction effect on both Co and TiN by adjusting the pH value. From the results of Examples 11, 14 and Proportional Reaction 3, it was found that as the organic acid content decreases, the etching rate of metallic materials decreases, and the etching rate of non-metallic materials also tends to decrease.

[0030] Etching compositions of Examples 15-16 and proportions 4-5 were prepared according to the components and corresponding contents listed in Table 5. [Table 5]

[0031] To evaluate the residual organic matter derived from the composition after wafer surface treatment, the present invention employs the following technical means: A Co blanket wafer is selected, diced into 5cm x 5cm pieces, and then placed in a single-substrate rotary cleaning apparatus. A cleaning process is performed under the conditions of a processing time of 3 minutes, a rotation speed of 600 rpm, and a temperature of 40°C. After the processing is complete, the wafer is removed and transferred to the single-substrate cleaning apparatus. Rinsing is performed for a processing time of 30 seconds, at a rotation speed of 600 rpm, and at a temperature of 25°C, followed by drying with high-purity nitrogen gas. Subsequently, surface elemental analysis is performed by XPS to measure the elemental abundances of C, N, O, and Co. Specific test results are shown in Table 6. [Table 6]

[0032] As is clear from Table 6, the Co surface treated in the examples of the composition exhibits a high abundance of Co and low abundance of N and C. This indicates that the amount of residual organic matter in the composition system is lower than in the proportional system, which is advantageous for subsequent processes on the Co layer (e.g., filling of the related structure with tungsten (W) or other metals). [Table 7]

[0033] Table 7 shows data illustrating the solubility of the compositions for CoF2 and CoO in some examples, with deionized water used for the blank test. The test method employed in this invention is as follows: Equal amounts of CoF2 / CoO were dissolved in 1 L of the composition solution or ultrapure water, respectively, and the solutions were stabilized. The cobalt ion concentration was then measured by ICP-MS. As a result, it was confirmed that the solubility of the compositions of this invention for CoF2 / CoO was significantly higher than that of deionized water.

[0034] Based on the above examples and proportional test results, it has been found that the etching composition of the present invention has excellent cleaning ability for residual polymers, metal oxides, and fluorides after plasma ashing, maintains high compatibility with TiN and Low-K materials, has a wide process window, and has extremely high potential for industrial applications.

[0035] The embodiments of the present invention are suitable for implementation and do not limit the present invention in any way. Those skilled in the art can realize equivalent effective embodiments by making changes or modifications to the technical content disclosed above. However, any modifications or equivalent changes and modifications made to the above embodiments based on the technical idea of ​​the present invention, without departing from the content of the technical solution means of the present invention, are all included within the scope of the technical solution means of the present invention.

Claims

1. An etching composition characterized by comprising hydroxylamine, a surfactant, a metal corrosion inhibitor, an amine-based pH adjuster, an organic acid, and water.

2. The etching composition according to claim 1, The present invention is characterized by containing 0.5% to 10% of the aforementioned hydroxylamine.

3. The etching composition according to claim 1, The surfactant is characterized by being contained in an amount of 0.001 to 10%.

4. The etching composition according to claim 1, The surfactants mentioned above include ethylene glycol monobutyl ether, ethylene glycol glycidyl ether, poly(ethylene glycol-propylene glycol) monobutyl ether, diethylene glycol dimethyl ether, propylene glycol phenyl ether, propylene glycol methyl ether, dodecylamine polyoxyethylene ether, polyethylene glycol, polyethylene glycol-propylene glycol copolymer, vinylpyrrolidone-vinyl acetate copolymer, n-hexanol, 1,2-pentanediol, 1,2-propanediol, 1,3 - Characterized by being one or more selected from propanediol, benzyl alcohol, dioxane, ethanol, n-propanol, isopropanol, n-butanol, SUPERWET-320, SUPERWET-340, SUPERWET-360, SURFYNOL420, SURFYNOL440, coconut fatty acid diethanolamide, dodecyltrimethylammonium chloride, myristyltrimethylammonium chloride, benzalkonium chloride, cetyltrimethylammonium bromide, and tetraheptylammonium bromide.

5. The etching composition according to claim 1, The metal corrosion inhibitor is characterized by being contained in an amount of 0.1 to 5%.

6. The etching composition according to claim 1, The metal corrosion inhibitor is characterized by being one or more selected from pyrazole, 1-methylpyrazole, 3,5-dimethylpyrazole, pyrazine, benzotriazole, methylbenzotriazole, 1H-benzotriazolemethanol, 1,2,4-triazole-3-carboxylate methyl, 5-benzyl-1H-tetrazole, 1-phenyl-5-mercaptotetrazole, 5-benzylthio-1H-tetrazole, 5-methyltetrazole, 2-mercaptothiadiazole, methimazole, mercaptoimidazole, and 3-mercapto-4-methyl-4H-1,2,4-triazole.

7. The etching composition according to claim 1, The aforementioned amine-based pH adjuster is characterized by being contained in an amount of 0.05 to 3%.

8. The etching composition according to claim 1, The amine-based pH adjuster is characterized by being one or more selected from diethylene glycolamine, ethanolamine, ethylenediamine, diethanolamine, diethylenetriamine, triethylenetetramine, hydroxyethylethylenediamine, N-methylethanolamine, 3-amino-1-propanol, isopropanolamine, diisopropanolamine, triisopropanolamine, and 1,8-diazabicyclo[5.4.0]undeca-7-ene.

9. The etching composition according to claim 1, The present invention is characterized by containing 0.05% to 5% of the aforementioned organic acid.

10. The etching composition according to claim 1, The organic acid is characterized in that it is a carboxylic acid having a nitrogen atom or an oxygen atom at the α-position.

11. In the etching composition according to claim 10, The organic acid is characterized by being one or more selected from glycolic acid, lactic acid, tonsillic acid, malic acid, citric acid, tartaric acid, gluconic acid, hydroxymalonic acid, pyridine-2-carboxylic acid, 2,3-pyridinedicarboxylic acid, 2,6-pyridinedicarboxylic acid, 1H-1,2,4-triazole-3-carboxylic acid, pyrazole-3-carboxylic acid, glycine, alanine, valine, leucine, isoleucine, methionine, proline, tryptophan, serine, tyrosine, cysteine, phenylalanine, asparagine, glutamine, threonine, aspartic acid, glutamic acid, lysine, arginine, histidine, and pyrrolidine.

12. An application for using the etching composition according to any one of claims 1 to 11 for cleaning in a cobalt layer process of 7 nm or more.

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