Cleaning solution for removing etching residue

Abstract

This invention provides a cleaning solution for removing etching residues, comprising: an oxidant, water, an organic solvent, a fluoride, an inorganic acid, and a metal corrosion inhibitor. The cleaning solution of this invention exhibits strong cleaning power, effectively and selectively removing TiN and TiSi hard masks in 3D-NAND structures, and has a low corrosion rate on tungsten (W) metals and non-metallic materials (such as SiON, SiN, and SiO2), thus achieving selective protection. It also has a large operating window, especially at 25–60°C, effectively ensuring that the TiN / W and TiSi / W etching rate ratios are greater than 10. Suitable for batch spin cleaning, it shows promising application prospects in the field of semiconductor wafer cleaning.

Description

Technical Field

[0001] This application relates to cleaning solutions for semiconductor devices, and more particularly to a cleaning solution for removing etching residues. Prior Technology

[0002] In recent years, flash memory technology has developed rapidly, especially 3D flash memory structures. 3D-NAND is an emerging type of flash memory that overcomes the limitations of 2D or planar NAND flash memory by stacking memory chips together, making it a better storage device than hard drive drives. As people continue to pursue products with lower power consumption, lighter weight, and better performance, 3D-NAND is finding wider application in electronic products.

[0003] Materials such as tungsten, titanium nitride, and titanium silicon are widely used in semiconductor devices. Etching is a common method for processing tungsten, titanium nitride, and titanium silicon into specified patterns. In non-memory-retention semiconductor memory devices, tungsten, titanium nitride, and titanium silicon are commonly used to construct patterned structures. With the continuous development of memory technology, especially 3D-NAND memory, the patterns are becoming increasingly refined and complex. Therefore, the requirements for etching tungsten, titanium nitride, and titanium silicon are becoming increasingly stringent, posing a significant challenge to the performance of the etching solution.

[0004] Numerous reports, both domestically and internationally, describe highly selective etching of TiN to protect tungsten metal and non-metallic materials. CN109642159A reports an acidic fluorine-containing chemical with high metal nitride etching properties and broad, excellent compatibility (including tungsten and low-k materials). CN105431506A provides a composition for selectively etching TiN or photoresist residues while simultaneously being compatible with copper, tungsten, and low-k materials. The etching rates for tungsten and low-k materials can be effectively controlled below 2 Å / min, while the TiN etching rate can reach approximately 80 Å / min. While these two formulations effectively improve the TiN / W selective etching ratio and provide good protection for low-k materials, they cannot effectively remove TiSi. Patent CN101233601A discloses a method for selectively removing metal silicates / metal nitrides. This composition contains hydrogen peroxide and a fluoride source, effectively etching nickel, tungsten, cobalt, titanium, metal alloys, metal silicates, and metal nitrides without corroding the dielectric and substrate. However, this formulation lacks protection for tungsten. Patent CN201110150434 discloses a fluorinated etching solution exhibiting a 1:1 to 1:3 selective etching ratio of silicon oxide to metal silicates. However, this selectivity is low, resulting in significant damage to low-k materials while removing metal silicates. Summary of the Invention

[0005] To address the problems in existing technologies that simultaneously fail to effectively remove TiSi and TiN hard masks, maintain high TiN / W and TiSi / W selective etch ratios, and exhibit low corrosion rates for tungsten and low-k materials, this application provides a cleaning solution for removing etching residues, comprising: an oxidant, a fluoride, an inorganic acid, a metal corrosion inhibitor, water, and an organic solvent.

[0006] Furthermore, the oxidant is selected from one or more of hydrogen peroxide, persulfate, monopersulfate, peracetic acid, ammonium peracetate, ammonium persulfate, ammonium chlorate, ammonium perchlorate, ammonium iodate, ammonium periodate, ammonium bromate, ammonium perbromate, potassium permanganate, ferric trifluoride, ferric chloride, ferric nitrate, or 1,4-benzoquinone.

[0007] Further, the fluoride is selected from one or more of hydrogen fluoride, ammonium fluoride, ammonium hydrogen fluoride, ammonium fluoroborate, fluoroboric acid, fluorosilicic acid, ammonium fluorosilate, hexafluorotitanic acid, ammonium hexafluorotitanic acid, or tetraalkylammonium fluoride (NR1R2R3R4F).

[0008] Furthermore, the inorganic acid is selected from one or more of nitric acid, hydrochloric acid, sulfuric acid, pyrosulfuric acid, phosphoric acid, pyrophosphoric acid, hydrobromic acid, perchloric acid, perbromic acid, periodic acid, orthoperiodic acid, or selenic acid.

[0009] Furthermore, the organic solvent is a monool, a polyol, an alkanolamine, or their derivatives.

[0010] Further, the organic solvent is selected from one or more of methanol, ethanol, ethylene glycol, glycerol, 1,2-propanediol, 1,3-propanediol, n-propanol, isopropanol, n-butanol, isobutanol, benzyl alcohol, phenethyl alcohol, tetrahydrofurfuryl alcohol, propylene glycol monomethyl ether, ethylene glycol monomethyl ether, 1,3-benzenedimethanol, 1,4-benzenedimethanol, 1,2-benzenedimethanol, ethanolamine, diethanolamine, triethanolamine, diethylene glycolamine, methyl diethanolamine, n-propanolamine, isopropanolamine, or 2-aminobutanol.

[0011] Furthermore, the metal corrosion inhibitor is an amine or its derivative with more than 4 carbon atoms.

[0012] Further, the metal corrosion inhibitor is selected from one or more of the following: n-butylamine, n-pentylamine, n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine, n-decylamine, n-undecylamine, n-dodecylamine, cyclopentylamine, cyclohexylamine, cycloheptylamine, cyclooctylamine, benzylamine, phenethylamine, 2-methyl-3-phenyl-2-propaneamine, isooctylamine, tert-butylamine, 1,6-hexanediamine, 1,7-heptanediamine, 1,8-octanediamine, dibutylamine, dipentylamine, dihexylamine, diheptylamine, dioctylamine, 2-methylhexylamine, 8-amino-n-octanol, 8-amino-n-octanoic acid, or phenylalanine.

[0013] Furthermore, the oxidant has a mass percentage content of 0.1% to 50%.

[0014] Furthermore, the fluoride content is 0.01% to 5% by mass.

[0015] Furthermore, the inorganic acid has a mass percentage content of 0.1% to 10%.

[0016] Furthermore, the metal corrosion inhibitor has a mass percentage content of 0.01%-3%.

[0017] Furthermore, the water content is 20% to 80% by mass.

[0018] Furthermore, the organic solvent has a mass percentage content of 10% to 50%.

[0019] All percentages above refer to mass percentage content.

[0020] All reagents used in this application are commercially available.

[0021] Compared with the prior art, the advantages of the present invention are:

[0022] This invention provides a novel wet cleaning formulation. The cleaning solution of this invention exhibits strong cleaning power, effectively and selectively removing TiN and TiSi hard masks in 3D-NAND structures. It also shows a low etching rate for tungsten (W) metals and non-metallic materials (such as SiON, SiN, and SiO2), thus achieving selective protection. Furthermore, it has a large operating window, especially at temperatures between 25°C and 60°C, effectively ensuring a TiN / W and TiSi / W etching rate ratio greater than 10. This makes it suitable for batch spin cleaning and shows promising application prospects in the field of semiconductor wafer cleaning. Simple Explanation of the Diagram

[0023] none Implementation

[0024] The advantages of the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0025] Examples 1-30 and Comparative Examples 1-5 of this application were prepared according to the ingredients and their contents in Table 1.

[0026] Table 1. Components and their contents (%) of each embodiment and comparative example water organic solvents Oxidizing agent Fluorides Inorganic acids Metal corrosion inhibitors Example 1 61.85 Glycerin: 30 H₂O₂: 6 HF: 0.05 HNO3: 1.2 Octylamine: 0.90 Example 2 69.89 Ethylene glycol: 18 H2O2 : 10 HF: 0.06 HNO3: 1.2 nonylamine: 0.85 Example 3 50.12 1,3-Propanediol: 30 H2O2: 15 NH4 HF2: 0.18 H₂SO₄: 1.7 n-Heptylamine: 3.00 Example 4 53.11 1,3-Propanediol: 30 H2O2: 15 NH4 HF2: 0.18 H₂SO₄: 1.7 n-Heptane: 0.01 Example 5 51.10 Ethylene glycol monomethyl ether: 25 Ammonium persulfate: 20 NH4 BF4: 1.20 HCl: 2.2 dodecylamine: 0.50 Example 6 72.12 Propylene glycol monomethyl ether: 12 Peracetic acid: 12 HF: 0.08 H3PO4 :2.5 2-Methyl-3-phenyl-2-propanamine: 1.30 Example 7 77.70 Methanol: 10 Ammonium periodate: 9 NH4 F: 0.20 H5 IO6: 2.35 Cyclooctylamine: 0.75 Example 8 76.10 1,2-Propanediol: 10 Peracetic acid: 10 NH4 BF4: 1.20 HBr: 1.8 8-Amino-n-Octanol: 0.90 Example 9 36.10 1,2-Propanediol: 50 Peracetic acid: 10 NH4 BF4: 1.20 HBr: 1.8 8-Amino-n-Octanol: 0.90 Example 10 77.80 1,4-Benzenedimethanol: 16 1,4-Benzoquinone: 2.2 H2SiF6: 1.00 HClO4: 1.0 Phenylethylamine: 2.00 Example 11 71.45 1,2-Benzenedimethanol: 20 Ferric chloride: 6 (NH4)2TiF6: 0.65 H₂SeO₄: 1.10 Dihexylamine: 0.80 Example 12 74.90 Tetrahydrofurfuryl alcohol: 15 H₂O₂: 9 NH4 F: 0.15 H3PO4 :0.1 Dioctylamine: 0.85 Example 13 65.00 Tetrahydrofurfuryl alcohol: 15 H₂O₂: 9 NH4 F: 0.15 H3PO4 :10 Dioctylamine: 0.85 Example 14 51.95 1,3-Benzenediethanol: 6 Glycerin: 30 Persulfate: 10 (NH4)2TiF6: 0.20 HIO4: 1.15 8-Aminooctanoic acid: 0.70 Example 15 59.78 Isopropanol: 30 Ferric fluoride: 6 HBF4: 0.12 HNO3: 3.3 Benzylamine: 0.80 Example 16 57.20 Tetrahydrofurfuryl alcohol: 15 n-Propanol: 5 Peracetic acid: 10 H2O2 : 10 Tetramethylammonium fluoride: 0.30 H2SO4: 1.5 Octylamine: 1.00 Example 17 63.77 Propylene glycol monomethyl ether: 20 n-Butanol: 5 Ferric nitrate: 2.6 Persulfate: 5.5 Tetraethylammonium fluoride: 0.33 H3PO4: 1.2 Phenylalanine: 1.60 Example 18 51.83 Methyldiethanolamine: 30 H2O2: 15 NH4 F: 0.12 H₂S₂O₇: 1.3 tert-Butylamine: 1.75 Example 19 64.67 Glycerin: 25 Ammonium chlorate: 7.5 HF: 0.08 H3PO4 :1.8 Cyclohexylamine: 0.95 Example 20 46.95 Glycerin: 15 n-Propanol: 15 Persulfate: 7 Peracetic acid: 13 H2 TiF6: 0.80 HBrO4: 1.0 Cyclopentanylamine: 1.25 Example 21 61.89 Glycerin: 30 H₂O₂: 6 Tetramethylammonium fluoride: 0.01 HNO3: 1.2 Octylamine: 0.90 Example 22 56.9 Glycerin: 30 H₂O₂: 6 Tetramethylammonium fluoride: 5 HNO3: 1.2 Octylamine: 0.90 Example 23 83.6 Propylene glycol monomethyl ether: 12 Peracetic acid: 0.1 HF: 0.1 H3PO4 :3.0 1,7-Heptanediamine: 1.20 Example 24 33.7 Propylene glycol monomethyl ether: 12 Peracetic acid: 50 HF: 0.1 H3PO4 :3.0 1,7-Heptanediamine: 1.20 Example 25 20.0 Ethylene glycol: 47.4 H2O2 : 30 (NH4)2SiF6:0.9 H₂SO₄: 1.2 Undecylamine: 0.5 Example 26 80.0 Ethylene glycol: 11.4 H₂O₂: 6 (NH4)2SiF6:0.9 H₂SO₄: 1.2 Undecylamine: 0.5 Example 27 73.93 Ethanolamine: 15 Persulfate: 8 NH4 HF2: 0.12 HCl: 2.0 8-Amino-n-Octanol: 0.95 Example 28 67.1 Methyldiethanolamine: 20 Ammonium persulfate: 10 Tetraethylammonium fluoride: 0.4 HNO3: 1.5 Dipentylamine: 1.0 Example 29 76.4 Diethylene glycolamine: 12 Peracetic acid: 7.5 HF: 0.1 H3PO4 :3.2 n-Hexylamine: 0.8 Example 30 51.65 Isopropanolamine: 25 H2O2 : 20 NH4 BF4: 1.0 H2SO4: 1.5 Octylamine: 0.85 Comparative Example 1 91.85 / H₂O₂: 6 HF: 0.05 HNO3: 1.2 Octylamine: 0.90 Comparative Example 2 63.05 Glycerin: 30 H₂O₂: 6 HF: 0.05 / Octylamine: 0.90 Comparative Example 3 61.90 Glycerin: 30 H₂O₂: 6 / HNO3: 1.2 Octylamine: 0.90 Comparative Example 4 67.85 Glycerin: 30 / HF: 0.05 HNO3: 1.2 Octylamine: 0.90 Comparative Example 5 62.75 Glycerin: 30 H₂O₂: 6 HF: 0.05 HNO3: 1.2 /

[0027] Effect verification

[0028] The cleaning solutions prepared according to the formulations in Table 1 for Examples 1, 3, 4, 8, 9, 12, 13, 16, 19, 21-27, 30 and Comparative Examples 1-5 were used to clean blank wafers at 25°C to 60°C.

[0029] The tests used tungsten (W) blank wafers, titanium nitride (TiN) blank wafers, titanium silicon (TiSi) blank wafers, and SiON blank wafers. Each blank wafer was sliced ​​to a size of 5*5cm and processed in a single-wafer rotary washer for 3-15 minutes, preferably 5 minutes, with a rotation speed of 200-600 rpm, preferably 300 rpm. After processing, the wafers were removed, rinsed, and dried with high-purity nitrogen.

[0030] The corrosion rate testing methods for metallic materials (tungsten, titanium nitride, titanium silicon) are as follows: 1) Measure the resistance (R1) of a 5*5cm blank metal wafer using a metal thin film thickness gauge; 2) Place the 5*5cm blank metal wafer to be tested in a single-wafer rotary cleaner for 5 minutes at a speed of 300 rpm; 3) Remove the 5*5cm blank metal wafer, clean it with deionized water, dry it with high-purity nitrogen, and then use a metal thin film thickness gauge to test the resistance (R2) of the blank metal wafer; 4) The etching rate can be calculated by inputting the changes in the resistance value and the processing time into a suitable program. The calculation formula is as follows:

[0031] R1 and R2 are the resistance values ​​of the blank metal wafer; T is the microcontroller processing time; K is a coefficient, and the K value is different for different metal materials.

[0032] The following is a test method for the corrosion rate of non-metallic materials (SiON): 1) The first thickness D1 of the non-metallic material layer (SiON) on a 5*5cm non-metallic blank wafer was measured using an automatic thin film thickness gauge; 2) Place the 5*5cm blank wafer to be tested in a single-wafer rotary washer for 5 minutes at a speed of 300 rpm; 3) Remove the 5*5cm blank wafer, clean it with deionized water, dry it with high-purity nitrogen, and then use an automatic thin film thickness gauge to measure the second thickness D2; 4) The corrosion rate can be calculated by inputting the changes in the thickness value and the processing time into a suitable program. The calculation formula is as follows: D1 and D2 are the first and second thicknesses of the non-metallic blank wafer, respectively; T is the microcontroller processing time.

[0033] The cleaning results are shown in Table 2 (ER in the table represents the etching rate).

[0034] Table 2 Cleaning results of various embodiments and comparative examples temperature (°C) SiON ER (Å / min) W ER(Å / min) TiN ER (Å / min) TiSi ER (Å / min) TiN / W TiSi / W Example 1 25 0.21 0.35 16.21 12.65 46.31 36.14 Example 3 25 0.15 0.02 6.39 5.42 319.50 271.00 Example 4 25 0.71 0.91 12.72 9.73 13.98 10.69 Example 8 40 1.36 2.36 73.55 56.34 31.17 23.87 Example 9 40 1.28 2.79 75.70 89.36 27.13 32.03 Example 12 50 4.78 6.23 89.34 76.35 14.34 12.26 Example 13 50 1.26 0.99 90.70 83.36 91.62 84.20 Example 16 60 7.23 6.79 210.61 170.36 31.02 25.09 Example 19 60 8.59 8.36 199.22 213.46 23.83 25.53 Example 21 25 0.01 0.21 4.39 3.16 20.90 15.05 Example 22 25 6.73 2.21 23.79 35.21 10.76 15.93 Example 23 25 0.15 0.11 1.39 7.39 12.64 67.18 Example 24 25 3.83 5.36 54.76 59.03 10.22 11.01 Example 25 40 3.16 5.79 139.31 120.79 24.06 20.86 Example 26 40 3.01 2.18 81.15 74.37 37.22 34.11 Example 27 40 2.15 1.79 78.92 69.74 44.09 38.96 Example 30 40 4.03 7.12 103.91 86.52 14.59 12.15 Comparative Example 1 25 0.31 0.47 13.21 4.57 28.11 9.72 Comparative Example 2 25 0.27 2.16 12.74 4.48 6.11 2.07 Comparative Example 3 25 0.01 0.45 15.46 0.02 34.35 0.04 Comparative Example 4 25 0.01 0.02 0.05 1.33 2.50 66.50 Comparative Example 5 25 0.33 7.86 15.79 14.21 2.01 1.81

[0035] As can be seen from Example 1 and Comparative Example 1, the etching rate ratios of TiN / W and TiSi / W are reduced in the cleaning solution without added organic solvents, especially the TiSi / W etching rate ratio, which decreases significantly. The test results from Example 1 and Comparative Example 2 show that the etching rates of tungsten (W) and non-metals (SiON) are higher in the cleaning solution without added inorganic acids, while the etching rates of TiN and TiSi are lower, and the etching rates of TiN / W and TiSi / W are relatively low. Example 1 and Comparative Example 3 show that the removal rate of TiSi is lower in the cleaning solution without added fluorides, and the etching rate of TiSi / W is also relatively low. Example 1 and Comparative Example 4 show that the etching rates of all materials are lower in the cleaning solution without added oxidant, especially TiN and TiSi. Example 1 and Comparative Example 5 show that the etching rates of tungsten and non-metals (SiON) are higher in the cleaning solution without added amine inhibitors, while the etching rates of TiN / W and TiSi / W are relatively low.

[0036] In summary, as can be seen from Examples 1, 3, 4, 8, 9, 12, 13, 16, 19, 21-27, 30 and Comparative Examples 1-5, only a cleaning solution that simultaneously includes specific amounts of oxidant, water, organic solvent, fluoride, inorganic acid, and metal corrosion inhibitor can effectively and selectively remove TiN and TiSi hard masks in 3D-NAND structures. Furthermore, it exhibits a low corrosion rate on tungsten (W) metals and non-metallic materials (such as SiON, SiN, and SiO2), thus achieving selective protection. The operating window is also large, especially at 25-60°C, effectively ensuring that the TiN / W and TiSi / W etching rate ratio is greater than 10.

[0037] The specific embodiments of the present invention have been described in detail above, but they are merely examples, and the present invention is not limited to the specific embodiments described above. For those skilled in the art, any equivalent modifications and substitutions to the present invention are also within the scope of the present invention. Therefore, all equivalent changes and modifications made without departing from the spirit and scope of the present invention should be covered within the scope of the present invention.

[0038] none

[0039] none

Claims

1. A cleaning solution for highly selectively removing TiN and TiSi hard mask etching residues in 3D-NAND structures, characterized in that the cleaning solution comprises an oxidant, a fluoride, an inorganic acid, a metal corrosion inhibitor, water, and an organic solvent; the inorganic acid is selected from one or more of nitric acid, hydrochloric acid, sulfuric acid, pyrosulfuric acid, phosphoric acid, pyrophosphoric acid, hydrobromic acid, perchloric acid, perbromic acid, periodic acid, orthoperiodic acid, or selenic acid; the oxidant has a mass percentage content of 0.1% to 50%; the organic solvent has a mass percentage content of 10% to 50%; the fluoride has a mass percentage content of 0.01% to 5%; the inorganic acid has a mass percentage content of 0.1% to 10%; the metal corrosion inhibitor has a mass percentage content of 0.01% to 3%; and the water has a mass percentage content of 20% to 80%.

2. The cleaning solution for highly selectively removing TiN and TiSi hard mask etching residues from 3D-NAND structures as described in claim 1, wherein, The oxidant is selected from one or more of hydrogen peroxide, persulfate, monopersulfate, peracetic acid, ammonium peracetate, ammonium persulfate, ammonium chlorate, ammonium perchlorate, ammonium iodate, ammonium periodate, ammonium bromate, ammonium perbromate, potassium permanganate, ferric trifluoride, ferric chloride, ferric nitrate, or 1,4-benzoquinone.

3. The cleaning solution for highly selectively removing TiN and TiSi hard mask etching residues from 3D-NAND structures as described in claim 1, wherein, The fluoride is selected from one or more of hydrogen fluoride, ammonium fluoride, ammonium hydrogen fluoride, ammonium fluoroborate, fluoroboric acid, fluorosilicic acid, ammonium fluorosilicate, hexafluorotitanic acid, ammonium hexafluorotitanic acid, or tetraalkylammonium fluoride.

4. The cleaning solution for highly selectively removing TiN and TiSi hard mask etching residues from 3D-NAND structures as described in claim 1, wherein, The organic solvent is one or more of monools, polyols, or alkanolamines and their derivatives.

5. The cleaning solution for highly selectively removing TiN and TiSi hard mask etching residues from 3D-NAND structures as described in claim 1, wherein, The organic solvent is selected from one or more of methanol, ethanol, ethylene glycol, glycerol, 1,2-propanediol, 1,3-propanediol, n-propanol, isopropanol, n-butanol, isobutanol, benzyl alcohol, phenethyl alcohol, tetrahydrofurfuryl alcohol, propylene glycol monomethyl ether, ethylene glycol monomethyl ether, 1,3-benzenedimethanol, 1,4-benzenedimethanol, 1,2-benzenedimethanol, ethanolamine, diethanolamine, triethanolamine, diethylene glycolamine, methyl diethanolamine, n-propanolamine, isopropanolamine, or 2-aminobutanol.

6. The cleaning solution for highly selectively removing TiN and TiSi hard mask etching residues from 3D-NAND structures as described in claim 1, wherein, The metal corrosion inhibitor is an amine or its derivative with more than 4 carbon atoms.

7. A cleaning solution for highly selectively removing TiN and TiSi hard mask etching residues from 3D-NAND structures as described in claim 6, wherein, The metal sustained-release agent is selected from one or more of the following: n-butylamine, n-pentylamine, n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine, n-decylamine, n-undecylamine, n-dodecylamine, cyclopentylamine, cyclohexylamine, cycloheptylamine, cyclooctylamine, benzylamine, phenethylamine, 2-methyl-3-phenyl-2-propaneamine, isooctylamine, tert-butylamine, 1,6-hexanediamine, 1,7-heptanediamine, 1,8-octanediamine, dibutylamine, dipentylamine, dihexylamine, diheptylamine, dioctylamine, 2-methylhexylamine, 8-amino-n-octanol, 8-amino-n-octanoic acid, or phenylalanine.