A highly conductive passivation layer and a method for forming it during high aspect ratio plasma etching.

Abstract

To provide a method for forming a high-aspect-ratio (HAR) structure during HAR etching processing to a substrate in a reaction chamber.SOLUTION: A method contains steps of: sequentially or simultaneously exposing a substrate to vapor of an etchant containing a hydrofluorocarbon or a fluorocarbon compound and an additive agent compound; providing a film to which the substrate is arranged thereon, and a patterned mask layer which is arranged onto the film; generating the hydrofluorocarbon or the fluorocarbon compound to be activated and the additive agent compound to be activated by activating a plasma; selectively etching the film from the patterned mask layer by progressing an etching reaction between a film that is not coated with the patterned mask layer and the activated hydrofluorocarbon or the fluorocarbon compound and the activated additive agent compound; and forming a high-aspect-ratio (HAR) patterned structure.SELECTED DRAWING: None

Description

[Technical Field]

[0001] Cross-references to related applications This application claims, for all purposes, the benefit of U.S. Patent Application No. 17 / 135,216 filed December 28, 2020, which is incorporated herein by reference in its entirety.

[0002] A method is disclosed for forming a highly conductive sidewall passivation layer on the sidewall using an etching gas as an additive, by doping with Si, C, and / or iodine elements during high aspect ratio (HAR) plasma etching, and / or introducing cyclic, aromatic, or heterocyclic chemical structures. [Background technology]

[0003] For over 50 years, Moore's Law has driven semiconductor manufacturers to continuously reduce device feature sizes to improve transistor / chip speed and capability while maintaining a cost advantage over competitors. This presents new challenges for manufacturing processes to meet the demands of ever-smaller feature sizes and dramatically increasing aspect ratios. For example, manufacturing 3D gate-stack NAND flash memory (3D-NAND) requires the ability to etch tiny hole features into 90+ NAND layers with aspect ratios exceeding 40. Using ultra-high aspect ratio (HAR) etching, it's necessary to etch over one trillion holes onto each wafer.

[0004] The vertical isotropy of etched features is achieved by ion transport during plasma sheath formation. In principle, positive and negative particles should follow the same orbits within the holes, equalizing the charge at the bottom of the HAR holes. However, due to electron shading effects, charge can accumulate at the bottom of the HAR mask pattern, potentially leading to incomplete etching, bowing, twisting, and variations in the critical dimension (CD) between the top and bottom of the HAR stack. Therefore, many efforts have been and continue in industry to eliminate or minimize sidewall charge-up during HAR etching in order to improve etching profiles and CD control.

[0005] It is known that contact hole distortion is caused by asymmetric charging of the contact hole sidewalls, which alters the local electric field within the contact hole and changes the orientation of reactive ions within the contact hole (see Kim et al., J.Vac.Sci.Technol.A, Vol.33, 021303-5 (2015) and Negishi et al, J.Vac.Sci.Technol.B, Vol.35, 051205 (2017)). In HAR etching, ellipticity has been used to assess mask degradation. High ellipticity (close to 100%) can help avoid HAR hole twisting and reduce distortion of the etching profile.

[0006] The following are some examples of methods that have been used to adjust the properties of the passivation layer during HAR etching, but as a natural consequence, 1) the gas / chemical supply setup to the process chamber becomes complicated, 2) the uniformity of the passivation layer at the top and bottom of the HAR feature becomes insufficient, and 3) the chamber cleaning problem - some metal-containing polymer deposits on the chamber walls, which is difficult to remove completely.

[0007] Sandhu et al., in U.S. Patent Application Publication No. 20070049018, disclose a method for HAR contact etching substantially perpendicular contact holes in an oxide layer using a hard photoresist mask. The plasma etching gas is a fluorinated hydrocarbon containing one of the following: CH2F2, C4F8;C3H3F5, C4F8;CHF3;C2F6;C2HF5, CH3F, or a combination thereof. The dopant molecule contains one of the following: HI, CH3I, carbon, potassium, calcium, PF6, BF3, chloride, AsF6, or a combination thereof. The doped plasma etching gas etches substantially perpendicular contact holes through the oxide layer by doping the carbon chain polymer formed along the sidewalls of the contact holes into a conductive state during the etching process. The conductive state of the carbon chain polymer reduces charge accumulation along the sidewalls, preventing twisting of the contact holes by bleeding off the charge and ensuring proper alignment of the active area with the landing region. Etching stops at the underlying substrate.

[0008] Bera et al., U.S. Patent No. 7,846,846,B2, discloses a method for etching HAR contact openings while preventing bowing and bending of the etching profile by forming a highly conductive thin film on the sidewall of each contact opening. The conductivity of the thin film on the sidewall is enhanced by periodic ion bombardment during the etching process. The etchant is a fluorocarbon / fluorohydrocarbon gas containing at least one of C2F4, C4F6, CH2F2, or C4F8, saturated or unsaturated linear, branched, or cyclic hydrofluorocarbons of C1-C5, such as C4H2F6, CHF3, CH2F2, or a combination thereof.

[0009] Nikhil et al.'s U.S. Patent No. 9,543,158 discloses various methods, apparatus, and systems for forming concave features in dielectric materials on substrates. In some cases, protective coatings are deposited using plasma-assisted atomic layer deposition, modified plasma-assisted atomic layer deposition, or plasma-assisted chemical vapor deposition. Etching chemicals are combinations of fluorocarbons and oxygen, C4F6, C4F3, N2, CO, CF4, and O2. The protective layer is a ceramic material or an organic polymer. For boron-containing materials such as boron oxide (BxOy) and boron nitride (BxNy), reactants include, but are not limited to, triisopropyl borate ([(CH3)2CHO]3B) and trimethylboron-d9 (B(CD3)3). Silicon oxide (Si x O y ) and silicon nitride (Si x N y For silicon-containing materials such as ), the reactant may be, for example, silane, halosilane, or aminosilane.

[0010] The HAR etching process has become a critical process for memory devices. Ion energy control by increasing the effective bias power of HAR features continues to advance. Significant efforts have been made to increase ion energy to overcome charge accumulation at the etching front within HAR holes. Based on bias power trends over the past few years, the required power would now exceed 20 kW. Increasing bias power presents numerous challenges. Preventing arc discharge, effective cooling, and power supply systems are all crucial for achieving high power capabilities. Furthermore, since neutral species move only by diffusion through holes, it becomes more difficult to compensate for neutral flux as the aspect ratio increases. [Overview of the project] [Problems that the invention aims to solve]

[0011] Therefore, it is necessary to achieve a highly conductive sidewall passivation layer while reducing bias power. [Means for solving the problem]

[0012] A method for forming a high aspect ratio (HAR) structure on a substrate in a reaction chamber during a high aspect ratio (HAR) etching process is disclosed, and this method is: Exposing a substrate sequentially or simultaneously to the vapor of an etchant containing hydrofluorocarbon or a fluorocarbon compound and an additive compound, wherein the substrate has a film disposed thereon and a patterned mask layer disposed on the film; Activating plasma to generate activated hydrofluorocarbons or fluorocarbon compounds and activated additive compounds; and The process involves proceeding with an etching reaction between a film not covered by a patterned mask layer and an activated hydrofluorocarbon or fluorocarbon compound and an activated additive compound, thereby selectively etching the film from the patterned mask layer and forming a HAR patterned structure; The disclosed methods may include one or more of the following embodiments: The process further includes the step of introducing an oxidizing agent into the reaction chamber, the oxidizing agent being selected from O2, O3, CO, CO2, NO, N2O, NO2, H2O, H2O2, COS, SO2, and combinations thereof; • The oxidizing agent is O2; • The oxidizing agent is O3; • The oxidizing agent is CO; • Before introducing it into the chamber, the etching compound, additive, and oxygen-containing gas are mixed to produce a mixture; • Introduce etching compounds and additives separately from the oxygen-containing gas; • Continuously introduce an oxygen-containing gas and an iodine-containing etching compound; • Oxygen-containing gas accounts for approximately 0.01% v / v to approximately 99.9% v / v of the total volume of etching compound, additives, and oxygen-containing gas; • Oxygen-containing gas accounts for approximately 0.01% v / v to approximately 10% v / v of the total volume of etching compound, additive, and oxygen-containing gas; The step includes introducing an inert gas into the reaction chamber, wherein the inert gas is selected from the group consisting of He, Ar, Xe, Kr, Ne, and N2; • The inert gas is Ar; • The inert gas is xe; • The inert gas is Kr; • Before introducing it into the chamber, the etching compound, additives, and inert gas are mixed to produce a mixture; • In addition to the inert gas, etching compounds and additives are introduced; • Inert gas is continuously introduced, and etching compounds and additives are introduced in pulses; • The inert gas accounts for approximately 0.01% v / v to 99.9% v / v of the total volume of the etching compound, additives, and inert gas vapors; • The inert gas accounts for approximately 90% v / v to 99.9% v / v of the total volume of the etching compound, additives, and inert gas vapors; • The substrate is a Si wafer; • The substrate is a crystalline silicon layer; • Forming patterned structures; • The patterned structure is a 3D NAND aperture; • The patterned structure is the contact hole; • The patterned structure is a 3D NAND contact hole; • The patterned structure is the DRAM contact; • The patterned structure is a channel hole; • The patterned structure is the 3D NAND channel hole; • The patterned structure is a 3D NAND slit contact; • The aperture is a stepped contact; • The aperture is a self-aligning contact; • The aperture is a self-aligned via; • The aperture is Super Beer; ·The plasma-activated fluorocarbon compound and the activated additive compound react with the film to form volatile by-products; ·The volatile by-products are removed from the reaction chamber; ·A highly conductive sidewall passivation layer is formed on the sidewalls of the HAR patterned structure; ·The conductivity of the highly conductive sidewall passivation layer formed using the activated hydrofluorocarbon or fluorocarbon compound and the activated additive compound is at least about 10% higher than the conductivity of the highly conductive sidewall passivation layer formed using the activated hydrofluorocarbon or fluorocarbon compound without adding the activated additive compound; ·The hydrofluorocarbon or fluorocarbon compound includes CF4, CHF3, C2F6, C3F8, C2HF5, C5F8, C6F6, C4F6, C4F8, saturated or unsaturated linear, branched, cyclic hydrofluorocarbons of C1 - C5, such as C4H2F6, CHF3, CH2F2, or combinations thereof; ·The hydrofluorocarbon or fluorocarbon compound is C4H2F6; ·The additive compound includes elements of silicon, carbon, and / or iodine having the following formula: C n R 1 R 2 R 3 I, SiR 1 R 2 R[[ID=​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​, and R 3 These are H, C1~C, and are independent of each other. 10 Selected from linear, branched, or cyclic, saturated or unsaturated, aromatic, heterocyclic, partially or fully fluorinated, substituted or unsubstituted alkyl groups; R 1 and R 2 , R 2 and R 3 , or R 1 and R 3 They may be linked together to form a cyclic group; • Additive compounds are selected from the following: [ka] [ka] • The above disclosed additive CR 1 R 2 R 3 I includes the following [ka] • The above disclosed additive SiR 1 R 2 R 3 I includes the following [ka] • The above disclosed additive SiR 1 R 2 I x F (2-x) This includes the following: [ka] • The above disclosed additive SiRI y F (3-y) This includes the following: [ka] • The disclosed additive SiI z F (4-z) This includes the following: [ka] • Disclosed additive C n F (2n+1) I includes the following [ka] • Additive compounds are selected from the following: Iodomethane CH3I (CAS No.: 74-88-4) Iodobenzene C6H5I (CAS No.: 591-50-4) 2-Iodopropane C3H7I (CAS No.: 75-30-9) 1-Iodopropane C3H7I (CAS No.: 107-08-4) 1-Iodoethane C2H5I (CAS No.: 75-03-6) Perfluorobutyl iodide C4F9I (CAS No.: 423-39-2), Difluoroiodomethane CHIF2 (CAS No.: 1493-03-4) Difluoroiodine (pentafluoroethyl)silane C2F7ISi (CAS No.: 36972-59-5) 1-(difluoroiodosilyl)-2-methylbenzene C7H7F2ISi (CAS No.: 174711-76-3), Difluoroiodo(trifluoromethyl)silane CF5ISi (CAS No.: 27668-68-4) Triethyliodosilane C6H 15 ISi (CAS No.: 1112-49-8) Fluorotriiodosilane FI3Si (CAS No.: 16865-60-4) Bifluorobiodosilane F2I2Si (CAS No.: 27669-15-4), Trifluoroiodosilane F3ISi (CAS No.: 27668-68-4), Iodotrimethylsilane C3H9ISi (CAS No.: 16029-98-4), or Diiodosilane SiH2I2 (CAS number: 13760-02-6); • The additive compound is iodomethane CH3I (CAS number: 74-88-4); • The additive compound is iodobenzene C6H5I (CAS number: 591-50-4); • The additive compound is 2-iodopropane C3H7I (CAS number: 75-30-9); The additive compound is 1-iodopropane C3H7I (CAS number: 107-08-4); • The additive compound is 1-iodoethane C2H5I (CAS number: 75-03-6); • The additive compound is perfluorobutyl iodide C4F9I (CAS number: 423-39-2); The additive compound is difluoroiodomethane CHIF2 (CAS No.: 1493-03-4); The additive compound is difluoroiodo(pentafluoroethyl)silane C2F7ISi (CAS number: 36972-59-5); The additive compound is difluoroiodo(pentafluoroethyl)silane C2F7ISi (CAS number: 36972-59-5); The additive compound is 1-(difluoroiodosilyl)-2-methylbenzene C7H7F2ISi (CAS number: 174711-76-3); The additive compound is difluoroiodo(trifluoromethyl)silane CF5ISi (CAS number: 27668-68-4); • Additive compound is triethyliodosilane C6H 15 It is ISi (CAS number: 1112-49-8); • The additive compound is fluorotriiodosilane FI3Si (CAS number: 16865-60 -4) is; The additive compound is bifluorobioiodosilane F2I2Si (CAS number: 27669-15-4); The additive compound is trifluoroiodosilane F3ISi (CAS number: 27668-68-4); The additive compound is iodotrimethylsilane C3H9ISi (CAS number: 16029-98-4); The additive compound is diiodosilane SiH2I2 (CAS number: 13760-02-6); The film is a silicon-containing film that includes O and / or N, and optionally contains dopants such as B, C, P, As, Ga, In, Sn, Sb, Bi, and / or Ge, and combinations thereof; The film is a silicon-containing film that includes oxygen; • The film is a silicon-containing film that includes nitrogen. The film is a silicon-containing film that optionally contains dopants such as B, C, P, As, Ga, In, Sn, Sb, Bi, and / or Ge, and combinations thereof; • Silicon-containing films include silicon oxide (SiO), silicon nitride (SiN), crystalline Si, polysilicon (p-Si), polycrystalline silicon, amorphous silicon, low dielectric constant SiCOH, SiOCN, SiC, SiON, and Si a O b H c C d N e (a>0; b, c, d, e≧0), including alternating layers of SiO and SiN(ONON), and alternating layers of SiO and p-Si(OPOP); • The silicon-containing film contains oxygen, nitrogen, carbon, hydrogen, or a combination thereof; • Silicon-containing film is SiO x N y H z C k And x is in the range of 0 to 2, y is in the range of 0 to 4, z is in the range of 0 to approximately 1, and k is in the range of 0 to 1; • The silicon-containing film includes an SiO layer; • The silicon-containing film is a SiN layer; • The silicon-containing film consists of alternating layers of SiO and SiN(ONON); • The silicon-containing film consists of alternating layers of SiO and p-Si (OPOP); • The silicon-containing film contains dopants such as B, C, P, As, Ga, In, Sn, Sb, Bi, and / or Ge; The alternating layers are silicon oxide, silicon nitride, polysilicon, crystalline silicon, SiOCH, SiON, and Si a O b Cc N d H e Includes layers of (a>0; b, c, d, e≧0), or combinations thereof; • The alternating layers contain oxygen atoms, nitrogen atoms, carbon atoms, hydrogen atoms, or combinations thereof; • The alternating layers are silicon-containing films; The alternating layers consist of layers of silicon oxide and layers of silicon nitride; The alternating layers consist of alternating layers of silicon oxide and silicon nitride; The alternating layers are alternating layers of silicon oxide and silicon nitride; The alternating layers consist of silicon dioxide layers and polysilicon layers; The alternating layers consist of alternating layers of silicon dioxide and polysilicon; The alternating layers are alternating layers of silicon dioxide and polysilicon; • Alternating layers are selectively etched from the hard mask layer; The alternating layers are selectively etched from the aC layer; Alternating layers are selectively etched from the doped carbon layer; Alternating layers of silicon oxide and silicon nitride are selectively etched from the aC layer; Alternating layers of silicon oxide and silicon nitride are selectively etched from the doped carbon layer; Alternating layers of silicon dioxide and polysilicon are selectively etched from the aC layer; Alternating layers of silicon dioxide and polysilicon are selectively etched from a doped carbon layer; • The silicon oxide layer is selectively etched away from the hard mask layer; • The silicon oxide layer is selectively etched from the aC layer; • The silicon oxide layer is selectively etched from the doped carbon layer; • The silicon nitride layer is selectively etched away from the hard mask layer; • The silicon nitride layer is selectively etched from the aC layer; The silicon nitride layer is selectively etched from the doped carbon layer; • The polysilicon layer is selectively etched away from the hard mask layer; • The polysilicon layer is selectively etched from the aC layer; • The polysilicon layer is selectively etched from the doped carbon layer; • A silicon-containing film is selectively etched from an amorphous carbon layer, a doped amorphous carbon layer, a photoresist layer, an anti-reflective layer, or an organic planarization layer; The silicon oxide layer is selectively etched from an amorphous carbon layer, a doped amorphous carbon layer, a photoresist layer, an anti-reflective layer, or an organic planarization layer; • The etching compound etches both the silicon oxide layer and the silicon nitride layer at a high etching rate; The patterned mask layer is an aC layer, a doped aC layer, a photoresist layer, an anti-reflective layer, an organic planarization layer, a polysilicon layer, a metal oxide layer, such as oxides of Ti, Al, Zr, Hf, etc., and combinations thereof; • A hard mask layer is placed on top of the silicon-containing layer; • The hard mask layer is a patterned hard mask layer; The hard mask layer is an amorphous carbon layer, a doped amorphous carbon layer, a photoresist layer, an anti-reflective layer, an organic planarization layer, or a combination thereof; The hard mask layer is a layer of CVD, PECVD, ALD, PEALD, or spin-on deposition (SOD) amorphous carbon or doped amorphous carbon, silicon-containing spin-on mask, or carbon-containing spin-on mask; • The hard mask layer is an amorphous carbon (aC) layer; • The hard mask layer is a doped carbon layer; • The doped amorphous carbon layer is a boron-doped aC layer; • The doped amorphous carbon layer is a tungsten-doped aC layer; • The HAR patterned structure formed on the film has an aspect ratio of approximately 1:1 to approximately 200:1; • The HAR patterned structure formed on the film has an aspect ratio of approximately 1:1 to approximately 20:1; • The HAR patterned structure formed on the film has an aspect ratio of approximately 21:1 to approximately 60:1; • The HAR patterned structure formed on the film has an aspect ratio of approximately 21:1 to approximately 200:1; • The HAR patterned structure formed on the film has an aspect ratio of approximately 61:1 to approximately 200:1; The process further includes introducing additional etching gases into the reaction chamber, where the additional etching gases include cC4F8, C4F8, cC5F8, C5F8, C4F6, CF4, CH3F, CF3H, CH2F2, C3HF7, C3F6, C3H2F6, C3H2F4, C3H3F5, C4HF7, C5HF9, C3F6, C3F8, CF3I, C2F3I, C2F5I, C3F7I, 1-iodoheptafluoropropane (1-C3F7I), 2-iodoheptafluoropropane (2-C3F7I) ), C3HF7, COS, FNO, FC≡N, CS2, SO2, SF6, trans-1,1,1,4,4,4-hexafluoro-2-butene (trans-C4H2F6), cis-1,1,1,4,4,4-hexafluoro-2-butene (cis-C4H2F6), hexafluoroisobutene (C4H2F6), trans-1,1,2,2,3,4-hexafluorocyclobutane (trans-C4H2F6), 1,1,2,2,3-pentafluorocyclobutane (C4H3F5), 1,1 Selected from the group consisting of ,2,2-tetrafluorocyclobutane (C4H4F4), cis-1,1,2,2,3,4-hexafluorocyclobutane (cis-C4H2F6), and combinations thereof; • Etching compounds and additives are introduced separately from additional etching gases; • Add an additional etching gas of approximately 0.01% v / v to approximately 99.99% v / v to the etching compound and additives; • Apply RF power to activate the plasma; • The plasma is activated by RF power ranging from approximately 25W to approximately 100,000W; • By using hydrofluorocarbon or fluorocarbon-containing additives, the bias power is lower compared to etching without additives; • By using hydrofluorocarbon or fluorocarbon-containing additives, the bias power is at least approximately 10% lower than when no additives are used. The etching pressure is in the range of approximately 1 mTorr to approximately 100 Torr; The etching pressure is in the range of approximately 1 mTorr to approximately 50 Torr; The etching pressure is in the range of approximately 1 mTorr to approximately 10 Torr; The etching pressure is in the range of approximately 1 mTorr to approximately 50 mTorr; • Introduce the vapor of the etching compound and additives at a flow rate in the range of approximately 0.1 sccm to approximately 1 slm; • Introduce the etching compound vapor at a flow rate in the range of approximately 0.1 sccm to 1 slm; • Introduce the additive vapor at a flow rate in the range of approximately 0.1 sccm to 1 slm; • Maintain the substrate at a temperature in the range of approximately -100°C to approximately 500°C; • Maintain the substrate at a temperature in the range of approximately 20°C to 150°C; • Maintain the substrate at a temperature in the range of approximately 20°C to 110°C; and • Measure the etching compound under plasma conditions using a quadrupole mass spectrometer, optical emission spectrometer, FTIR, or other radical / ion measurement tool.

[0013] Furthermore, a method for forming HAR patterned structures is also disclosed, and this method is: A step of exposing a substrate to vapors of C4H2F6 and CH3I sequentially or simultaneously, wherein the substrate has a film disposed thereon and a patterned mask layer disposed on the film; A step of activating the plasma to generate activated C4H2F6 and CH3I; and A step of selectively etching the film from the patterned mask layer by carrying out an etching reaction between a film not covered by the patterned mask layer and activated C4H2F6 or CH3I, thereby forming a HAR patterned structure; The disclosed methods may include one or more of the following embodiments: The process further includes the step of introducing an oxidizing agent into the reaction chamber, the oxidizing agent being selected from O2, O3, CO, CO2, NO, N2O, NO2, H2O, H2O2, COS, SO2, and combinations thereof; The process further includes the step of introducing an inert gas into a reaction chamber, wherein the inert gas is selected from the group consisting of He, Ar, Xe, Kr, Ne, and N2; • A highly conductive sidewall passivation layer is formed on the sidewall of the HAR patterned structure; The conductivity of a highly conductive sidewall passivation layer formed using activated C4H2F6 and activated CH3I is at least approximately 10% higher than the conductivity of a highly conductive sidewall passivation layer formed using activated C4H2F6 without the addition of activated CH3I; • The HAR patterned structure formed on the film has an aspect ratio of approximately 1:1 to approximately 200:1; • Further includes introducing additional etching gases into the reaction chamber, where the additional etching gases are cC4F8, C4F8, cC5F8, C5F8, C4F6, CF4, CH3F CF3H, CH2F2, C3HF7, C3F6, C3H2F6, C3H2F4, C3H3F5, C4HF7, C5HF9, C3F6, C3F8, CF3I, C2F3I, C2F5I, C3F7I, 1-iodoheptafluoropropane (1-C3F7I), 2-iodoheptafluoropropane (2-C3F7I), C3HF7, COS, FNO, FC≡N, CS2, SO2, SF6, trans-1,1,1,4,4,4-hexafluoro-2-butene (trans-C4H2F6), cis-1,1,1, Selected from the group consisting of 4,4,4-hexafluoro-2-butene (cis-C4H2F6), hexafluoroisobutene (C4H2F6), trans-1,1,2,2,3,4-hexafluorocyclobutane (trans-C4H2F6), 1,1,2,2,3-pentafluorocyclobutane (C4H3F5), 1,1,2,2-tetrafluorocyclobutane (C4H4F4), and cis-1,1,2,2,3,4-hexafluorocyclobutane (cis-C4H2F6) and combinations thereof; and The film is a silicon-containing film that includes O and / or N, and optionally contains dopants such as B, C, P, As, Ga, In, Sn, Sb, Bi, and / or Ge, and combinations thereof.

[0014] Representation and Nomenclature The following detailed description and claims utilize a number of abbreviations, symbols, and terms that are generally well known in the art, including:

[0015] As used herein, the indefinite articles "a" or "an" refer to one or more.

[0016] As used herein, the terms “about,” “approximately,” or “about” in the text or claims mean ±10% of the stated value.

[0017] As used herein, "room temperature" in the text or claims means approximately 20°C to approximately 25°C.

[0018] The terms “wafer” or “patterned wafer” refer to a wafer having a stack of any existing films, including silicon-containing films, on a substrate, and a patterned hard mask layer on the stack of any existing films, including silicon-containing films, formed for pattern etching.

[0019] The term "substrate" refers to one or more materials on which a process is performed. A substrate may refer to a wafer or patterned wafer having one or more materials on which an etching process is performed. A substrate may be any suitable wafer used in the manufacture of semiconductors, photovoltaics, flat panels, or LCD-TFT devices. A substrate may also have one or more layers of different materials already deposited on it from a previous manufacturing step. For example, a wafer may include silicon layers (e.g., crystalline, amorphous, porous, etc.), silicon-containing layers (e.g., SiO2, SiN, SiON, SiCOH, etc.), metal-containing layers (e.g., copper, cobalt, ruthenium, tungsten, indium, platinum, palladium, nickel, ruthenium, gold, etc.), or combinations thereof. Furthermore, a substrate may be planar or patterned. A substrate may be a photoresist film patterned with an organic material. The substrate may be an oxide layer used as a dielectric material in MEMS, 3D NAND, MIM, DRAM, or FeRam device applications (e.g., ZrO2-based materials, HfO2-based materials, TiO2-based materials, rare earth oxide-based materials, ternary oxide-based materials, etc.), a nitride-based film used as an electrode (e.g., TaN, TiN, NbN), or a metal-containing or metal alloy-based film (e.g., InGaAs, In) which is a promising candidate to replace silicon in future CMOS systems. x O y (x=0.5~1.5, y=0.5~1.5), InSnO (ITO), InGaZnO (IGZO), InN, InP, In This may include As, InSb, In2S3, or In(OH)3, etc. Those skilled in the art will recognize that the terms “film” or “layer” as used herein refer to the thickness of any material that is arranged or spread over a surface, which may be a trench or a line. Throughout this specification and the claims, a wafer and any associated layer thereon are referred to as a substrate.

[0020] The term "pattern etching" or "patterned etching" refers to etching non-planar structures, such as stacks of silicon-containing films, beneath a patterned hard mask layer.

[0021] As used herein, the terms “etch” or “etch” mean the removal of material by ion bombardment, remote plasma, or chemical vapor phase reaction between an etching compound and / or plasma and an etching gas and a substrate, and refer to isotropic etching processes and / or anisotropic etching processes. Isotropic etching processes involve a chemical reaction between an etching compound and a substrate, removing a portion of the material on the substrate. This type of etching process includes chemical dry etching, vapor phase chemical etching, and thermal dry etching. Isotropic etching processes create lateral or horizontal etching profiles on the substrate. Isotropic etching processes create recesses or horizontal recesses in the sidewalls of pre-formed apertures on the substrate. Anisotropic etching processes include plasma etching processes (i.e., dry etching processes) in which the chemical reaction is accelerated vertically by ion bombardment, resulting in the formation of sidewalls perpendicular to the substrate along the edges of masked features (Manos and Flamm, Thermal etching an Introduction, Academic Press, Inc. 1989 pp.12-13). Plasma etching processes create vertical etching profiles on a substrate. Plasma etching processes create vertical vias, apertures, trenches, channel holes, gate trenches, stepped contacts, capacitor holes, contact holes, slit etchings, self-aligned contacts, self-aligned vias, supervias, and more on the substrate.

[0022] The term "mask" refers to a layer that resists etching. A mask layer can be placed on top of the layer to be etched. The term "mask layer" also refers to a hard mask layer. A mask layer may be an amorphous carbon (aC) layer, a doped aC layer, a photoresist layer, an anti-reflective layer, an organic planarization layer, or a combination thereof. A mask layer may also be a silicon layer such as polySi, a metal oxide such as Ti, Al, Zr, or Hf, or an oxide, or a combination thereof.

[0023] The term "aspect ratio" refers to the ratio of the height of a trench (or aperture) to its width (or aperture diameter).

[0024] The term "etching stop" refers to the layer beneath the layer being etched, which protects the layer below it.

[0025] The term "device channel" refers to a layer that is part of the actual device, and any damage to it will affect device performance.

[0026] The term "selectivity" refers to the ratio of the etching rate of one material to the etching rate of another material. The term "selective etching" means that one material is etched more than the other, or in other words, that the etching selectivity between the two materials is greater than or less than 1:1.

[0027] The terms "via," "aperture," "trench," and "hole" may be used interchangeably and generally refer to openings in interlayer insulation.

[0028] The terms "low bias power" or "reduced bias power" refer to bias power lower than that of the baseline process.

[0029] As used herein, the term “additive” refers to a compound or gas that is added to other etching compounds to improve, to some extent, the etching properties, such as improving profile characteristics such as bowing, CD, and ellipticity.

[0030] As used herein, the term "ellipticity" refers to a method for measuring the degradation of a mask, and in etching applications, the ellipticity of an etched hole is estimated for simplification by (width of short hole / width of long hole) * 100%; therefore, the ellipticity of a perfectly circular hole is defined as 100%.

[0031] As used herein, the abbreviation "NAND" refers to a "Negated AND" or "Not AND" gate, the abbreviation "2D" refers to a two-dimensional gate structure on a flat substrate, and the abbreviation "3D" refers to a three-dimensional or vertical gate structure in which gate structures are stacked vertically.

[0032] As used herein, the term “mercury probe” refers to an electrical probe device for rapid and non-destructive contact with a sample for electrical characterization. When the contact between mercury and the sample is ohmic (non-rectifier), a current-voltage measuring instrument can be used to measure resistance, leakage current, or current-voltage characteristics. Resistance can be measured with a bulk sample or a thin film. The thin film can be made of any material that does not react with mercury. The diameter of the mercury contact of the mercury probe used herein is 760 μm.

[0033] As used herein, the term "conductivity" is the reciprocal of electrical resistivity and represents the ability of a material to conduct electric current. As used herein, the unit of electrical conductivity is Siemens per centimeter (S / cm). This is measured using a mercury probe.

number

[0034] As used herein, the term “highly conductive sidewall passivation layer” refers to the electrical conductivity of a sidewall passivation layer that exceeds the conductivity of the C4F8 polymer, which is 2.14 × 10⁻⁶. -9It is calculated as S / cm.

[0035] It should be noted that the terms “film” and “layer” may be used interchangeably in this specification. It will be understood that a film may correspond to or be related to a layer, and that a layer may be called a film. Furthermore, those skilled in the art will recognize that, as used herein, the terms “film” or “layer” refer to the thickness of several materials applied or extended on a surface, and that the surface may range from as large as an entire wafer to as small as a trench or line.

[0036] In this specification, the terms “etching compound,” “etchant,” “etching gas,” and “process gas” may be used interchangeably when the etching compound is in a gaseous state at room temperature and ambient pressure. It is understood that the etching compound may correspond to or be related to an etching gas, etchant, or process gas, and that an etching gas, etchant, or process gas may refer to an etching compound.

[0037] In this specification, standard abbreviations for elements from the periodic table are used. It should be understood that elements may be represented by these abbreviations (for example, Si means silicon, N means nitrogen, O means oxygen, C means carbon, H means hydrogen, F means fluorine, etc.).

[0038] A unique CAS registry number (i.e., "CAS") assigned by the Chemical Abstract Service is provided to identify the specific molecule being disclosed.

[0039] Note that silicon-containing films such as SiN and SiO are enumerated throughout the specification and claims without providing their appropriate stoichiometry. Silicon-containing films include pure silicon (Si) layers such as crystalline Si, polysilicon (p-Si or polycrystalline Si), or amorphous silicon; silicon nitride (Si k N l) layer; silicon oxide (Si n O m ) layer; or a mixture thereof may be included, where k, l, m, and n are all in the range of 0.1 to 6. Preferably, the silicon nitride is Si k N l where k and I are each in the range of 0.5 to 1.5. More preferably, the silicon nitride is Si3N4. In this specification, SiN in the following description may be used to represent a Si k N l -containing layer. Preferably, the silicon oxide is Si n O m where n is in the range of 0.5 to 1.5 and m is in the range of 1.5 to 3.5. More preferably, the silicon oxide is SiO2. In this specification, SiO in the following specification may be used to represent a Si n O m -containing layer. The silicon-containing film may be a silicon-based dielectric material such as an organic-based or silicon oxide-based low dielectric constant dielectric material having SiOCH, such as Black Diamond II or III materials by Applied Materials, Inc. The silicon-containing film may be Si a O b N c where a, b, and c are in the range of 0.1 to 6. The silicon-containing film may also include dopants such as B, C, P, As, Ga, In, Sn, Sb, Bi, and / or Ge, and combinations thereof.

[0040] The term "independently" when used in the context of describing R groups is to be understood to mean that the R groups in question are selected independently not only of other R groups having the same or different subscripts or superscripts, but also of any additional species of the same R group. For example, in the formula MR 1 x (NR 2 R 3 ) (4-x) (M is an atom and x is 2 or 3), the two or three R 1 groups are independent of each other or of R 2 or R3 They may be the same, but they do not necessarily have to be identical. Furthermore, unless otherwise specified, the values ​​of the R group should be understood to be independent of each other when used in different formulas.

[0041] In this specification, a range may be expressed as approximately from one specific value and / or approximately to another specific value. Where such a range is expressed, it should be understood that other embodiments, along with all combinations within the range, are from one specific value and / or to another specific value.

[0042] References to “one embodiment” or “a certain embodiment” in this specification mean that certain features, structures, or characteristics described in relation to an embodiment are found in at least one embodiment of the present invention. This means that it may be included. The phrase "in one embodiment" in various places in this specification does not necessarily refer to the same embodiment, and other or alternative embodiments are not necessarily mutually exclusive with other embodiments. The same applies to the term "implementation."

[0043] For a further understanding of the nature and purpose of the present invention, the following detailed description should be referenced in conjunction with the accompanying drawings. In the drawings, similar elements are given the same or similar reference numerals. [Brief explanation of the drawing]

[0044] [Figure 1] This is the conductivity of C4H2F6 measured on a flat wafer, with and without the additive CH3I. [Figure 2] This is the conductivity of C4H2F6 measured on a flat wafer, with and without the additive C4F9I. [Figure 3] This is the conductivity of C4H2F6 measured on a flat wafer, with and without the additive SiH2I2. [Figure 4] This compares the ER and selectivity of C4H2F6 with and without the additive CH3I. [Figure 5] This is a comparison of the sidewalls of C4H2F6 Boeing with and without the additive CH3I. [Figure 6] This is a comparison of ellipticity with and without the additive CH3I. [Figure 7] This is a comparison of the critical dimension (CD) of C4H2F6 with and without CH3I additive at a bias power of 7000W. [Figure 8] This is a comparison of CDs for C4H2F6 with and without CH3I additive at a bias power of 5600W. [Figure 9] This is a comparison of CD values ​​for C4H2F6 with and without CH3I additive at a bias power of 4200W. [Figure 10] This refers to the chemical composition of various polymers and their electrical conductivity. [Modes for carrying out the invention]

[0045] A method is disclosed for forming a highly conductive sidewall passivation layer on the sidewalls using an etching gas as an additive by doping with Si, C, and / or iodine in a high aspect ratio (HAR) plasma etching process. The disclosed method uses an additive or additive chemical in a HAR plasma etching process to form a highly conductive sidewall passivation layer by doping with Si, C, and / or iodine. The highly conductive sidewall passivation layer may be a polymer passivation layer. The conductivity of the polymer passivation layer reduces charge accumulation along the sidewalls, prevents twisting of HAR structures such as holes by bleeding off the charge, and ensures proper control of critical dimension (CD) variations at low to no bias power levels. By utilizing the additive, the bias power may be at least about 10% lower compared to the case without the additive, and may even eliminate the need for bias power altogether.

[0046] When the sidewall charge is minimized, the plasma bias power required for the reactive ions to reach the bottom of the HAR trench is reduced. Therefore, the disclosed method can also be considered as low-bias energy plasma etching. In addition, the etching gas or process gas containing the disclosed additive does not contain elements that are difficult to clean, thereby minimizing the contamination of the reaction chamber and reducing the tool maintenance / downtime.

[0047] The disclosed method uses a hydrofluorocarbon etchant gas and an additive gas and relates to plasma etching a patterned wafer or substrate under reduced bias power for a predetermined time. The predetermined time can range from 0 seconds to 1000 seconds to stabilize the pressure and gas flow in the chamber before activating the plasma.

[0048] The disclosed additive or additive chemical substance contains elements of Si, C, and / or iodine having the following formula: CR 1 R 2 R 3 I, SiR 1 R 2 R 3 I, SiR 1 R 2 I x F (2-x) , SiRI y F (3-y) , SiI z F (4-z) or C n F (2n+1) I (where x = 1 to 2; y = 1 to 3; z = 1 to 4; R, R 1 , R 2 , and R 3 are each independently H, D (deuterium), C1 to C 10(Selected from linear, branched, or cyclic, saturated or unsaturated, aromatic, heterocyclic, partially or fully fluorinated, substituted or unsubstituted alkyl groups). 1 and R 2 , R 2 and R 3 , or R 1 and R 3 They may be linked together to form a cyclic group.

[0049] The above disclosed additive CR 1 R 2 R 3 I may include the following: [ka]

[0050] The above disclosed additive SiR 1 R 2 R 3 I may include the following: [ka]

[0051] The above disclosed additive SiR 1 R 2 I x F (2-x) This may include the following: [ka]

[0052] The above disclosed additive SiRI y F (3-y) This may include the following: [ka]

[0053] The above disclosed additive SiI z F (4-z) This may include the following: [ka]

[0054] Disclosed additive C n F (2n+1) I may include the following: [ka]

[0055] Table 1 lists exemplary disclosed additives containing the elements Si, C, and / or iodine. These molecules are commercially available or can be synthesized by methods known in the art. Their structural formulas, CAS numbers, and boiling points are shown in the table. Disclosed additives containing the elements Si, C, and / or iodine may also include their isomers.

[0056] [Table 1]

[0057] [Table 2]

[0058] Since high volatility is desirable for etching gases, high volatility is also required for additive chemicals. As mentioned above, small alkyl groups are used as substituents on the silicon in the additives, and the additives disclosed thereby have high volatility. Another advantage of using alkyl substituents is that the formation of insufficient carbon leaving groups increases the likelihood of carbon being incorporated into the sidewall passivation. Since the conductivity can be improved by including aromatic groups in the sidewall passivation, the use of aromatic substituents on silicon has also been proposed in new molecules. Substitution on aromatic groups is also interesting because the conductivity can be altered in the electronics of the aromatic ring. However, those skilled in the art will understand that low-volatility etching materials can also be used. Low-volatility etching materials are obtained by heating a container or cylinder containing the low-volatility etching material and a gas line connected to the etching tool, and blowing an inert gas through the liquid low-volatility etching material. It can be used in various ways, including by using a bubbler method in which the material is incorporated, or by heating the source of the low-volatility etching material to increase its volatility.

[0059] The disclosed additives are suitable for tuning the properties of passivation layers formed on the sidewalls of high aspect ratio holes / trenches. Sidewall passivation and downward etching occur simultaneously. The passivation layer may originate from a carbon source in the plasma etching gas, a reaction between the etching gas and the exposed material, or redeposition of by-products from the etching process. Additives to the etchant significantly influence the chemical composition of the sidewall passivation by introducing conductive elements and / or chemical bonds, thereby positively affecting the conductivity of the sidewall passivation. During the plasma etching process, the potential at the bottom of the structure becomes positively charged while the sidewalls become negatively charged, creating an undesirable local electric field within the structure. Only high-energy ions with energy greater than the potential difference along the local electric field can reach the bottom. As the conductivity of the sidewall passivation increases, the sidewall charge dissipates rapidly. The required bias power is below that of the baseline process.

[0060] The disclosed etching gas may be a fluorocarbon / hydrofluorocarbon. Exemplary disclosed fluorocarbons / hydrofluorocarbons include CF4, CH3F, C2F6, C3F8, C2HF5, C5F8, C6F6, C4F6, C4F8, saturated or unsaturated linear, branched, or cyclic hydrofluorocarbons of C1-C5, such as C4H2F6, CHF3, CH2F2, or combinations thereof.

[0061] The disclosed fluorocarbons / hydrofluorocarbons include silicon oxide (SiO), silicon nitride (SiN), pure silicon (Si) (such as crystalline Si), polysilicon (p-Si or polycrystalline Si); amorphous silicon, low dielectric constant SiCOH, SiOCN, SiC, SiON, and Si a O b H c C d N e(a>0; b, c, d, e≧0); Suitable for etching silicon-containing films containing layers of metal-containing films (e.g., copper, cobalt, ruthenium, tungsten, indium, platinum, palladium, nickel, ruthenium, gold, etc.). The silicon-containing film may contain alternating layers of SiO and SiN (ONON) or alternating layers of SiO and p-Si (OPOP). The silicon-containing film contains O and / or N. The silicon-containing film may also contain dopants such as B, C, P, As, Ga, In, Sn, Sb, Bi, and / or Ge, and combinations thereof.

[0062] The disclosed fluorocarbons / hydrofluorocarbons and additives are provided with a purity higher than 95% v / v, preferably higher than 99.99% v / v, and more preferably higher than 99.999% v / v. The disclosed fluorocarbons / hydrofluorocarbons and additives contain less than 5% by volume of trace gaseous impurities, including impurity gases such as N2 and / or H2O and / or CO2 in amounts of less than 150 ppm by volume. Preferably, the water content in the plasma etching gas is less than 20 ppm by weight. The purified product can be produced by distillation and / or by passing the gas or liquid through a suitable adsorbent such as a 4 Å molecular sieve.

[0063] The disclosed fluorocarbons / hydrofluorocarbons and additives contain any of their isomers in amounts less than 10% v / v, preferably less than 1% v / v, more preferably less than 0.1% v / v, and even more preferably less than 0.01% v / v, which can be purified by gaseous or liquid distillation to remove the isomers and may provide better process repeatability.

[0064] The disclosed fluorocarbon / hydrofluorocarbon is derived from an embedded landing layer or material, which is a metal layer located at the bottom of a structure that is etched in most applications. The ion-containing layer is selectively etched. The disclosed fluorocarbon / hydrofluorocarbon does not etch the metal landing layer. The embedded landing layer may be an etching stop layer or a diffusion barrier layer. The material of the metal landing layer may be a tungsten metal worldline in a 3D NAND structure, and / or another metal such as W, Cu, Al, Ru, Pt, Ti, Ta, Ni, Co, Mo, Mn, Pd, Ir, Nb, Cr, Rh, V, Au, Ag or a combination thereof, and / or an etching stop layer such as a metal or metal oxide or nitride layer (e.g., AlO, WO, HfO, TiO, TaO, InO, CrO, RuO, CoO, MoO, ZrO, SnO, TiN, TaN, HfN, AlN, WN, MoN, NiN, NbN, CrN, RuN, CoN, ZrN, SnN or a combination thereof).

[0065] The disclosed fluorocarbons / hydrofluorocarbons can be used to plasma etch silicon-containing films onto substrates. The disclosed plasma etching method may be useful in the manufacture of semiconductor devices such as NAND or 3D NAND gates, or flash or DRAM memory or transistors such as fin-shaped field-effect transistors (FinFETs), gate-all-around (GAA) FETs, nanowire FETs, nanosheet FETs, forksheet FETs, complementary FETs (CFETs), bulk complementary metal oxide semiconductors (bulk CMOS), MOSFETs, and fully depleted silicon-on-insulator (FD-SOI) structures. The disclosed iodine-containing etching compounds may be useful in other areas of application, such as different front-end of the line (FEOL) and back-end of the line (BEOL) etching applications. Furthermore, the disclosed iodine-containing etching compounds may be used to interconnect memory to logic on substrates, to etch Si in 3D through-silicon via (TSV) etching applications, and in MEMS applications.

[0066] The disclosed etching method includes providing a reaction chamber having a substrate disposed therein. The reaction chamber may be an enclosure or chamber in any device in which the etching method is performed, such as a reactive ion etching (RIE), CCP with a single or multiple frequency RF source, inductively coupled plasma (ICP), or microwave plasma reactor, or other types of etching systems capable of selectively removing a portion of a silicon-containing film or generating active species. Those skilled in the art will recognize that different plasma reaction chamber designs provide different electronic temperature control. Suitable commercially available plasma reaction chambers include, but are not limited to, the Applied Materials magnetically enhanced reactive ion etcher sold under the trademark eMAX®, or the Lam Research Dual CCP reactive ion etcher dielectric etching product line sold under the trademark 2300® Flex®, or the Advanced Micro-Fabrication Equipment Inc. China (AMEC) Primo SSC HD-RIE etcher. The RF power in them may be pulsed to control the plasma characteristics and thereby further improve the etching performance (selectivity and damage).

[0067] The reaction chamber may contain one or more substrates. For example, the reaction chamber may contain 1 to 200 silicon wafers having a diameter of 25.4 mm to 450 mm. The substrate may be any suitable substrate used in semiconductor, photovoltaic, flat panel, or LCD-TFT device manufacturing. Examples of suitable substrates include wafers such as silicon, silica, glass, Ge, SiGe, GeSn, InGaAs, GaSb, InP, or GaAs wafers. The wafer may contain a silicon-containing film or layer, or a previously manufactured step. It will have multiple films or layers on it from the p. The layers may or may not be patterned. Suitable examples of layers include, but are not limited to, silicon (amorphous silicon, p-Si, crystalline silicon, any of which may be further p-doped or n-doped with B, C, P, As, Ga, In, Sn, Sb, Bi and / or Ge), silica, silicon nitride, silicon oxide, silicon oxynitride, Si a O b H c C d N e (wherein a > 0 and b, c, d, e ≥ 0), Ge, SiGe, GeSn, InGaAs, GaSb, InP; amorphous carbon with or without dopants, anti-reflective coatings, photoresist materials, metal oxides such as AlO, TiO, HfO, ZrO, SnO, TaO, or metal nitride layers such as AlN, ZrN, SnN, HfN, titanium nitride, tantalum nitride, etc., or combinations thereof, mask layer materials; silicon nitride, polysilicon, crystalline silicon, silicon carbide, SiON, SiCN, or combinations thereof, device channel materials such as crystalline silicon, epitaxial silicon, doped silicon, Si a O b H c C d N e Examples of etching stop layer materials include those where a > 0 and b, c, d, e ≥ 0 (wherein a formula a > 0) or combinations thereof. aC (amorphous carbon) is a carbon film deposited using the PE-CVD process. Its composition is primarily carbon, with some hydrogen components. Doped aC is an amorphous carbon film in which dopants are additionally deposited during the deposition process. Dopants may include boron, zirconium, aluminum, titanium, and tungsten. Carbon films can also be deposited using a spin-on process, as opposed to the PE-CVD process. The silicon oxide layer can form dielectric materials such as organic-based or silicon oxide-based low-dielectric-constant dielectric materials (e.g., porous SiCOH films). An exemplary low-dielectric-constant dielectric material is the trademarked Black Diamond. It is sold by Applied Materials in II or III. Furthermore, layers containing tungsten or precious metals (e.g., platinum, palladium, rhodium, or gold) may be used. Furthermore, an example of a silicon-containing film is Si a O b H c C d N e (wherein a > 0; b, c, d, e ≥ 0) is possible. Throughout the specification and claims, wafers and any associated layers thereof are described as substrates.

[0068] The disclosed etching method includes pumping the reaction chamber to a high vacuum after placing the substrate in the chamber and before introducing the disclosed fluorocarbon / hydrofluorocarbon into the chamber. The high vacuum can be in the range of 0.01 mTorr to 10 mTorr.

[0069] An inert gas is also introduced into the reaction chamber to receive the plasma. The inert gases include He, Ar, Xe, Kr, Ne, and N. 2、 This may be he or a combination thereof. The etching gas and inert gas may be mixed before introduction into the chamber so that the inert gas constitutes about 0.01% v / v to about 99.9% v / v of the resulting mixture. Alternatively, the inert gas may be introduced into the chamber continuously, while the etching gas is introduced intermittently.

[0070] The disclosed etching gas vapor and inert gas are activated by plasma to generate an activated etching gas. The plasma decomposes the etching gas into radical form (i.e., activated etching gas). The plasma may be generated by applying RF or DC power. The plasma may be generated by RF power in the range of about 25 W to about 100,000 W. The plasma may be generated distally or within the reactor itself. The plasma may be generated in dual CCP or ICP mode by RF applied to both electrodes. The RF frequency of the plasma may be in the range of 100 kHz to 1 GHz. Different RF sources at different frequencies may be combined and applied to the same electrode. Plasma RF pulses may be used to control molecular fragmentation and reactions in the substrate. Those skilled in the art will recognize suitable methods and apparatus for such plasma processing.

[0071] The activated etching gas from the chamber exhaust may be measured using a quadrupole mass spectrometer (QMS), optical emission spectrometer, FTIR, or other radical / ion measurement tool to determine the type and number of species generated. If necessary, the flow rates of the etching gas and / or inert gas may be adjusted to increase or decrease the number of radical species generated.

[0072] The disclosed etching gas and additives may be mixed with other gases or co-reactants either before or during their introduction into the reaction chamber. Preferably, the gases may be mixed before introduction into the chamber to provide a uniform concentration of the mixed gases.

[0073] Alternatively, the vapors of the hydrofluorocarbon etching compound and additives may be introduced into the chamber independently of other gases, for example, when it is easier to deliver two or more gases independently or when they react with each other.

[0074] In another option, hydrofluorocarbon etching gas and additive gas are the only two gases used during the etching process.

[0075] In another alternative configuration, hydrofluorocarbon etching gas, additive gas, and inert gas are the only three gases used during the etching process.

[0076] Other exemplary gases or co-reactants include, but are not limited to, oxidizing agents such as O2, O3, CO, CO2, NO, N2O, NO2, H2O, H2O2, COS, SO2, and combinations thereof. The disclosed etching gases / additives and oxidizing agents may be mixed together before being introduced into the reaction chamber.

[0077] Alternatively, the oxidizing agent may be introduced into the chamber continuously, while the etching gas is introduced intermittently. The oxidizing agent may constitute approximately 0.01% v / v to approximately 99.99% v / v of the mixture introduced into the chamber (99.99% v / v represents the introduction of nearly pure oxidizing agent with respect to the continuous introduction option).

[0078] Other exemplary gases from which the disclosed hydrofluorocarbon etching gases and additive gases may be used include cC4F8, C4F8, cC5F8, C5F8, C4F6, CF4, CH3F, CF3H, CH2F2, C3HF7, C3F6, C3H2F6, C3H2F4, C3H3F5, C4HF7, C5HF9, C3F6, C3F8, CF3I, C2F3I, C2F5I, C3F7I, 1-iodoheptafluoropropane (1-C3F7I), 2-iodoheptafluoropropane (2-C3F7I), C3HF7, COS, FNO, FC≡N, CS2, SO2, H2S, SF6, trans- Examples include 1,1,1,4,4,4-hexafluoro-2-butene (trans-C4H2F6), cis-1,1,1,4,4,4-hexafluoro-2-butene (cis-C4H2F6), hexafluoroisobutene (C4H2F6), trans-1,1,2,2,3,4-hexafluorocyclobutane (trans-C4H2F6), 1,1,2,2,3-pentafluorocyclobutane (C4H3F5), 1,1,2,2-tetrafluorocyclobutane (C4H4F4), and cis-1,1,2,2,3,4-hexafluorocyclobutane (cis-C4H2F6) or combinations thereof. For example, a disclosed iodine-containing etching compound containing about 1% v / v to about 25% v / v may be used, with the remainder being C4F6 or cC4F8. As shown in the following examples, the combination of the disclosed iodine-containing etching compound and a conventional etching gas increases the etching rate while maintaining higher selectivity between the substrate and the layer etched in association with the disclosed iodine-containing etching compound. It can be done.

[0079] The vapors of the disclosed etching compounds and / or additives are introduced into a reaction chamber containing the substrate and the silicon-containing film. The vapors may be introduced into the chamber at flow rates ranging from about 0.1 sccm to about 1 slm. For example, with respect to a 200 mm wafer size, the vapors may be introduced into the chamber at flow rates ranging from about 5 sccm to about 50 sccm. Alternatively, with respect to a 450 mm wafer size, the vapors may be introduced into the chamber at flow rates ranging from about 25 sccm to about 250 sccm. Those skilled in the art will recognize that the flow rates may vary depending on the tool. The vapors of the disclosed etching compounds and / or additives may be introduced into the reaction chamber pre-mixed or separately.

[0080] The disclosed etching compounds and / or additives may be supplied either in their raw form or in blends with a suitable solvent such as ethylbenzene, xylene, mesitylene, decane, or dodecane. The disclosed compounds and additives may be present in the solvent at various concentrations. The vapor form of the disclosed compounds and additives can be produced by evaporating the raw or blended solutions of the disclosed compounds and additives via a conventional evaporation step such as direct evaporation or bubbling. The raw or blended disclosed compounds and additives may be supplied in liquid form to an evaporator to evaporate them before being introduced into the reactor. Alternatively, the raw or blended disclosed compounds and additives may be evaporated by passing a carrier gas through a vessel containing the disclosed compounds and additives, or by bubbling a carrier gas through the disclosed compounds and additives. Carrier gases may include, but are not limited to, Ar, He, N2, Xe, Kr, Ne, and mixtures thereof. The carrier gas and the disclosed compounds and additives are then introduced into the reactor as vapors.

[0081] If necessary, the container containing the disclosed compounds and additives may be heated to a temperature at which the disclosed compounds and additives become liquid and have sufficient vapor pressure. The container may be maintained at a temperature in the range of, for example, about 0°C to about 150°C. The line from the bubbler to the etching tool may also be maintained at a temperature above the container temperature. Those skilled in the art will recognize that the container temperature can be adjusted in known ways to control the amount of disclosed compounds and additives evaporated.

[0082] The disclosed hydrofluorocarbon etching gas and additive gas vapors, as well as additional etching gases, may be mixed before being introduced into the reaction chamber. The additional etching gases may account for approximately 0.01% v / v to approximately 99.99% v / v of the mixture introduced into the chamber.

[0083] The disclosed etching gas vapor and additional gases, such as inert gases or co-reactants, are activated by plasma to produce activated etching gas. The plasma decomposes the etching gas into radical forms or ions (i.e., activated etching gas). The plasma may be generated by applying RF or DC power. The plasma can be generated in a decoupled plasma etching reactor by RF source power ranging from approximately 25 W to approximately 100,000 W. The plasma may be generated distally or within the reactor itself. The plasma may be generated in dual CCP or ICP mode by RF applied to both electrodes, but is not limited to these. The RF frequency of the plasma may be in the range of 100 kHz to 1 GHz. Different RF sources at different frequencies may be combined and applied to the same electrode. Plasma RF pulses may be used as further bias power to control molecular fragmentation and reactions in the substrate. Those skilled in the art will recognize suitable methods and apparatus for such plasma processing.

[0084] Since the disclosed additives are used with hydrofluorocarbons or fluorocarbons, the bias power may be lower compared to etching without the additives. In the disclosed method, by utilizing the additives, the bias power may be at least about 10% lower than when the additives are not used, as can be seen in the following examples.

[0085] A disclosed method for forming a highly conductive sidewall passivation layer on a high aspect ratio patterned structure includes: i) introducing etchant vapor into a reactor containing a substrate; ii) forming an ion plasma from the etchant in the reactor by applying source power; iii) diffusing ions toward the substrate by applying reduced bias power so that portions of the substrate not covered by a patterned mask layer on the substrate are selectively etched away and a high aspect ratio patterned structure is formed; and iv) continuing the process for a predetermined time until a highly conductive sidewall passivation layer is formed on the sidewalls of the high aspect ratio patterned structure, and then turning off the source power and low bias power.

[0086] Here, the substrate has a film placed thereon and a patterned mask layer placed on the film. The etchant comprises a hydrofluorocarbon or fluorocarbon compound and an additive compound. The etchant may also contain co-reactants and / or an inert gas. After the etchant is introduced into the reactor, it is left to stand until equilibrium is reached. The reduced bias power can be at least 10% lower than without the addition of additives to the etchant. The predetermined time ranges from 1 second to 1000 seconds. The ratio of the hydrofluorocarbon or fluorocarbon compound to the additive compound is selected so that the newly formed portion of the sidewall is passivated and protected from further etching. The ratio of the hydrofluorocarbon or fluorocarbon compound to the additive compound introduced into the reactor can vary from 1:99 to 99:1 depending on the flow rate.

[0087] Before introducing the etchant into the reactor, the reactor is pumped to a high vacuum in the range of 0.001 mTorr to 100 mTorr, and after the etching process, the reactor can be purged with an inert gas.

[0088] The temperature of the reaction chamber can be controlled by controlling the temperature of the substrate holder or by controlling the temperature of the reactor wall. Apparatus used for heating the substrate is known in the art. The reactor wall is heated to a temperature sufficient to prevent condensation in the wall or reactor chamber, especially when a showerhead reactor is used in which the substrate temperature is higher than the wall temperature. A non-limiting exemplary temperature range in which the reactor wall can be heated includes the range of about -100°C (LN temperature) to about 500°C, preferably about 20°C to about 150°C, more preferably 20°C to about 110°C.

[0089] The pressure inside the reaction chamber is maintained at a condition suitable for the etchant or process gas for the portion of the substrate not covered by the patterned mask layer. Here, the etchant or process gas may include hydrofluorocarbon or fluorocarbon etching gases, additives, co-reactants, etc. For example, the pressure inside the reactor may be maintained at about 1 mTorr to about 100 Torr, preferably about 1 mTorr to about 50 Torr, more preferably about 1 mTorr to about 10 Torr, and even more preferably about 1 mTorr to about 50 mTorr.

[0090] Etching conditions can change during the etching process. For example, parameters such as gas flow rate, plasma power, pressure, and temperature may be higher or lower during the beginning of etching compared to the end of etching near the bottom of the hole or trench. Alternatively, different etching times may be used to improve performance, such as by reducing or increasing the polymer deposition rate. Different etching gases may be added at different points.

[0091] The disclosed etching method can provide high selectivity for mask layers, photoresists, etch stop layers, and device channel materials, and can not provide profile distortion in contact etching applications for HAR structures such as those having aspect ratios in the range of 1:1 to 200:1, such as DRAM and 3D NAND structures. Alternatively, aspect ratios in the range of 1:1 to 20:1 and 21:1 to 200:1. The disclosed etching method is suitable for etching HAR patterned structures having aspect ratios of 1:1 to 200:1. Alternatively, the disclosed etching method is suitable for etching HAR patterned structures having aspect ratios of approximately 1:1 to approximately 20:1, between approximately 21:1 and approximately 200:1, between approximately 1:1 and approximately 60:1, or between approximately 61:1 and approximately 200:1. [Examples]

[0092] The following non-limiting embodiments are provided to further illustrate embodiments of the present invention. However, the embodiments are not intended to be comprehensive and nor to limit the scope of the present invention as described herein.

[0093] In the following examples, experiments were conducted using either a commercially available LAM tool 4520XLe 200mm (CCP dual-frequency plasma) or a commercially available AMEC 300mm Primo SSC HD-RIE etcher. To demonstrate reproducibility, each etching test was repeated at least three times. The standard deviation of the mean of the three measurements is shown as error bars in the chart. Subsequently, the polymer composition was investigated by X-ray photoelectron spectroscopy (XPS).

[0094] Example 1: Measurement of the electrical conductivity of a polymer Figures 1-3 show the conductivity of C4H2F6 with and without the additives CH3I, C4F9I, or SiH2I2, respectively, measured on a flat wafer. Current (I)-voltage (V) was measured using a mercury probe. A drop of deionized water was added to the back of the wafer to improve contact resistance. This may help reduce measurement noise at low voltages. Under the same electric field strength, adding iodine molecules to the hydrofluorocarbon increases the measured current through the polymer and lowers the dielectric breakdown voltage. The conductivity of C4H2F6 with the additive is increased compared to the conductivity of C4H2F6 without the additive. See the current difference in Figures 1-3. As shown in Table 1, conductivity was calculated in an electric field of 0.2 MV / cm, and the increase in conductivity at an electric field of 0.2 MV / cm was >10%.

[0095] [Table 3]

[0096] Example 2: ONON hole pattern etching using CH3I as an additive CH3I shows promising performance on flat thin films (higher selectivity for aC mask and portability). Due to its increased conductivity, C4H2F6 was added to etching recipes for ONON (i.e., alternating SiO / SiN layers) hole pattern etching on patterned wafers or substrates. The patterned wafer has an ONON layer on which a hole-patterned amorphous carbon (aC) mask layer is deposited. The etching recipe may also include O2.

[0097] For preliminary screening, four conditions were tested for C4H2F6 / CH3I flow rates: 30 / 10 sccm, 35 / 5 sccm, 40 / 5 sccm, and 40 / 10 sccm. 30 / 10 sccm and 35 / 5 sccm represent the same total gas flow rate. Due to the high polymerizability of CH3I, etch stops were observed in SEM images when the CH3I flow rate was 10 sccm or higher. While the 40 / 5 sccm condition showed improved etching selectivity, further adjustment of the etching recipe is necessary. SEM conditions are as shown in the flow chart: Accel. voltage: 5.0 kV; Emission current: 20 μA; Magnification: ×30.0 k.

[0098] CH3I is highly polymerizable and can clog patterned mask layers, potentially causing etch stops at flow rates above 10 sccm when added to the ONON etching composition. Adding CH3I to the etching recipe shifts the process window for O2 flow rate from 68 sccm to 74-76 sccm. For the optimized CH3I recipe: ONON etching rate (ER): 510 nm / min (without CH3I, measured ONON ER is 516 nm / min); ONON / aC selectivity: 11.2-12 (without CH3I, ONON / aC selectivity is 11.4-12). Figures 4-9 compare ER, selectivity, sidewall bowing, ellipticity, and critical dimension (CD) of C4H2F6 with and without the additive CH3I, respectively, due to differences in bias power. Overall, the recipe with CH3I shows less dependence on bias power compared to the recipe without CH3I (ONON etching rate, selectivity, bowing, ellipticity, profile CD).

[0099] More specifically, as shown in Figure 6, at a bias power of 7000W, adding CH3I to the recipe did not show a significant change in the ellipticity of the aC mask holes, and the measured ellipticity was 93% for the recipe without CH3I and 94% for the recipe with CH3I. At a bias power of 5600W, the aC mask profile deteriorated with decreasing bias power in the recipe without CH3I, while little effect was observed in the recipe with CH3I. At a bias power of 4200W, the recipe with CH3I showed improvements in etching performance, including ER, selectivity, aC mask ellipticity, and tilt angle. The etching performance is summarized in Table 2.

[0100] [Table 4]

[0101] In summary, the use of the additive CH3I improves surface passivation (also known as the polymer layer) on the etch front and sidewalls of HAR features, and the passivation changes in response to variations in plasma etching conditions (RF power, process time, etc.). Furthermore, adding CH3I as an additive to hydrofluorocarbon etching gas reduces bias power by 40% without impairing etching performance such as etching rate, selectivity, ellipticity, and profile CD.

[0102] Example 3: Chemical composition of polymer and electrical conductivity of polymer Substrate: To obtain IV characteristics solely from the polymer, a low-resistivity Si substrate (less than 0.02 Ω·cm) was used for polymer deposition instead of an SiO2 substrate. To facilitate IV measurements using a mercury probe, the Si substrate was cut into 1-inch x 1-inch coupons.

[0103] Polymer deposition: The same deposition process conditions were used for C4F8, C4H2F6, C4F9I, C4F8 + C4F9I, and C4H2F6 + C4F9I; the thickness of the deposited polymer was measured with an ellipsometer; for the polymer on the ion block region, the thickness was measured at a position 1 mm away from the edge of the shield coupon.

[0104] Ramtool experimental conditions: RF source power: 750 W; bias power: 1500 W; Ar / etching gas (or gas mixture) / O2: 250 / 15 / 0; etching time: 30 seconds.

[0105] Figure 10 shows various polymer chemical compositions and the electrical conductivity of the polymers. The measured values of current (I) ~ voltage (V) were the same as those in Example 1. As shown, under the same electric field strength, the addition of iodine molecules to the hydrofluorocarbon induces a higher measured current and a lower breakdown voltage through the polymer. The conductivities at 0.2 MV / cm for various polymers and iodine molecule additives are as follows: C4F9I > C4H2F6 + C4F9I > C4F8 + C4F9I > C4H2F6 > C4F8. Polymers with a higher C - C:C - Fx / C - I ratio have a higher breakdown voltage and higher electrical strength. It is considered that the C - F bond contributes to the conductivity of the polymer. Polymers containing a large number of C - C bonds are less conductive than polymers containing a large number of C - F. x x

[0106] Table 3 shows the bond concentration ratio of C - C:C - F x / C - I (x is an integer). The bond concentration ratio of C - C:C - F x / C - I is C4F9I < C4F8 + C4F9I < C4F8 < C4H2F6 + C4F9I < C4H2F6 from low to high. The C - C bond is a non - polar covalent bond; the C - Fx / C - I bond is a polar covalent bond. The conductivity was calculated at an electric field of 0.2 MV / cm, and the increase in conductivity at an electric field of 0.2 MV / cm was >10%.

[0107]

Table 5

[0108] Due to the different conduction mechanisms in various electric fields, it is difficult to demonstrate how the chemical composition of a polymer and its electrical conductivity are related. However, generally, adding iodine to a polymer increases its conductivity, resulting in a bias power reduction of at least approximately 10% compared to the case without additives, and even eliminating the need for bias power altogether, without compromising etching performance such as etching rate, selectivity, ellipticity, and profile CD, as shown in Example 2.

[0109] It will be understood that many additional modifications in the details, materials, steps, and arrangement of the parts described and illustrated herein to illustrate the nature of the present invention can be made by those skilled in the art within the principles and scope of the invention set forth in the appended claims. Accordingly, the present invention is not intended to be limited to the specific embodiments shown above and / or in the appended drawings.

[0110] Embodiments of the present invention are shown and described herein, but can be modified by those skilled in the art without departing from the spirit and teachings of the invention. The embodiments described herein are merely exemplary and not limiting. Many variations and modifications of the compositions and methods are possible and fall within the scope of the invention. Accordingly, the scope of protection is not limited to the embodiments described herein, but is limited only by the claims, which include all equivalents of the subject matter of the claims.

Claims

1. A method for forming a high aspect ratio (HAR) patterned structure on a substrate in a reaction chamber during a high aspect ratio (HAR) etching process, Hydrofluorocarbon or fluorocarbon compound and SiH ２ I ２ Exposing the substrate sequentially or simultaneously to vapor of an etchant containing the following, wherein the substrate has a film disposed thereon and a patterned mask layer disposed thereon; The plasma is activated, and the activated hydrofluorocarbon or fluorocarbon compound and activated SiH ２ I ２ To generate and The film not covered by the patterned mask layer, the activated hydrofluorocarbon or fluorocarbon compound and the activated SiH ２ I ２ An etching reaction is carried out between the two to selectively etch the film from the patterned mask layer, thereby forming the HAR patterned structure; Includes, A highly conductive sidewall passivation layer is formed on the sidewall of the HAR patterned structure. The hydrofluorocarbon or fluorocarbon compound includes CF4, CH3F, CHF3, CH2F2, C2F6, C3F8, C2HF5, C4F6, C4F8, C4H2F6, C5F8, C6F6, saturated or unsaturated linear, branched or cyclic hydrofluorocarbons of C1 to C5, or combinations thereof. A method wherein the film is a silicon-containing film comprising a layer of metal-containing film selected from silicon oxide (SiO), silicon nitride (SiN), crystalline Si, polysilicon (p-Si or polycrystalline Si), amorphous silicon, low dielectric constant SiCOH, SiOCN, SiC, SiON, Si a O b H c C d N e (a>0; b, c, d, e≧0), copper, cobalt, ruthenium, tungsten, indium, platinum, palladium, nickel, ruthenium, and gold, alternating layers of SiO and SiN (ONON) or alternating layers of SiO and p-Si (OPOP), or a layer of dopant silicon-containing film containing B, C, P, As, Ga, In, Sn, Sb, Bi, and / or Ge, and combinations thereof.

2. The step further includes introducing an oxidizing agent into the reaction chamber, wherein the oxidizing agent is O ２ , O ３ , CO, CO ２ , NO, N ２ O, NO ２ , H ２ O, H ２ O ２ , COS, SO ２ The method according to claim 1, selected from O, CO, CO, NO, N, O, NO, H, O, H, O, COS, SO, and combinations thereof.

3. The process further includes the step of introducing an inert gas into the reaction chamber, wherein the inert gas is He, Ar, Xe, Kr, Ne, and N ２ The method according to claim 1, selected from the group consisting of the following.

4. The activated hydrofluorocarbon or fluorocarbon compound and the activated SiH ２ I ２ The conductivity of the highly conductive sidewall passivation layer formed using is the activated SiH ２ I ２ The method according to claim 1, wherein the conductivity of the highly conductive sidewall passivation layer formed using the activated hydrofluorocarbon or fluorocarbon compound without the addition of the above is 38 times higher.

5. The hydrofluorocarbon or fluorocarbon compound is C ４ H ２ F ６ The method according to claim 1.

6. The method according to claim 1, wherein the film is a silicon-containing film comprising O and / or N, and a dopant selected from B, C, P, As, Ga, In, Sn, Sb, Bi, and / or Ge, and combinations thereof.

7. The method according to claim 1, wherein the patterned mask layer is an a-C layer, a doped a-C layer, a photoresist layer, an anti-reflective layer, an organic planarization layer, a poly-Si layer, a metal oxide layer of a metal selected from Ti, Al, Zr, and Hf, or a combination thereof.

8. The method according to claim 1, wherein the HAR patterned structure formed on the film has an aspect ratio of 1:1 to 200:

1.

9. The further step includes introducing an additional etching gas into the reaction chamber, wherein the additional etching gas is C ４ F8, C ５ F ８ , C ４ F ６ CF ４ ,CH ３ F, CF ３ H, CH ２ F ２ , C ３ HF ７ , C ３ F ６ , C ３ H ２ F ６ , C ３ H ２ F ４ , C ３ H ３ F ５ , C ４ HF ７ , C ５ HF ９ , C ３ F ６ , C ３ F ８ CF ３ I, C ２ F ３ I, C ２ F ５ I, C ３ F ７ I,1-iodoheptafluoropropane(1-C ３ F ７ I), 2-iodoheptafluoropropane (2-C ３ F ７ I), C ３ HF ７ , COS, FNO, FC≡N, CS ２ SO ２ SF ６ The method according to claim 1, selected from the group consisting of the following, and combinations thereof.

10. A method for forming a HAR patterned structure, The substrate is C in the reaction chamber. ４ H ２ F ６ and SiH ２ I ２ A step of sequentially or simultaneously exposing the substrate to vapors thereof, wherein the substrate has a film disposed thereon and a patterned mask layer disposed thereon; The plasma is activated, and the activated C ４ H ２ F ６ and activated SiH ２ I ２ The steps to generate and The film not covered by the patterned mask layer and the activated C ４ H ２ F ６ and the SiH ２ I ２ A step of proceeding with an etching reaction between the two to selectively etch the film from the patterned mask layer, thereby forming the HAR patterned structure; Includes, A highly conductive sidewall passivation layer is formed on the sidewall of the HAR patterned structure. The aforementioned film is silicon oxide (SiO), silicon nitride (SiN), crystalline Si, polysilicon (p-Si or polycrystalline Si), amorphous silicon, low dielectric constant SiCOH, SiOCN, SiC, SiON, Si a O b H c C d N e (a>0; b, c, d, e≧0), copper, cobalt, A silicon-containing film comprising a layer of metal-containing film selected from ruthenium, tungsten, indium, platinum, palladium, nickel, ruthenium, and gold; alternating layers of SiO and SiN (ONON) or alternating layers of SiO and p-Si (OPOP); or a layer of dopant silicon-containing film containing B, C, P, As, Ga, In, Sn, Sb, Bi, and / or Ge, and combinations thereof.

11. Further comprising the step of introducing an oxidizing agent into the reaction chamber, wherein the oxidizing agent is O ２ , O ３ , CO, CO ２ , NO, N ２ O, NO ２ , H ２ O, H ２ O ２ , COS, SO ２ , and a combination thereof, the method according to claim 10.

12. The process further includes the step of introducing an inert gas into the reaction chamber, wherein the inert gas is He, Ar, Xe, Kr, Ne, and N ２ The method according to claim 10, selected from the group consisting of the following.

13. The activated C ４ H ２ F ６ and the conductivity of the highly conductive sidewall passivation layer formed using the activated SiH ２ I ２ is 38 times higher than the conductivity of the highly conductive sidewall passivation layer formed using the activated C ２ I ２ without adding the activated SiH ４ H ２ F ６ The method according to claim 10.

14. The method according to claim 10, wherein the HAR patterned structure formed on the film has an aspect ratio of 1:1 to 200:

1.

15. The further step includes introducing an additional etching gas into the reaction chamber, wherein the additional etching gas is C ４ F ８ , C ５ F ８ , C ４ F ６ CF ４ ,CH ３ F, CF ３ H, CH ２ F ２ , C ３ HF ７ , C ３ F ６ , C ３ H ２ F ６ , C ３ H ２ F ４ , C ３ H ３ F ５ , C ４ HF ７ , C ５ HF ９ , C ３ F ６ , C ３ F ８ CF ３ I, C ２ F ３ I, C ２ F ５ I, C ３ F ７ I,1-iodoheptafluoropropane(1-C ３ F ７ I), 2-iodoheptafluoropropane (2-C ３ F ７ I), C ３ HF ７ , COS, FNO, FC≡N, CS ２ SO ２ SF ６ , trans-1,1,1,4,4,4-hexafluoro-2-butene (trans-C ４ H ２ F ６ ), cis-1,1,1,4,4,4-hexafluoro-2-butene (cis-C ４ H ２ F ６ ), hexafluoroisobutene (C ４ H ２ F ６ ), trans-1,1,2,2,3,4-hexafluorocyclobutane (trans-C ４ H ２ F ６ ), 1,1,2,2,3-pentafluorocyclobutane (C ４ H ３ F ５ ), 1,1,2,2-tetrafluorocyclobutane (C ４ H ４ F ４ ), and cis-1,1,2,2,3,4-hexafluorocyclobutane (cis-C ４ H ２ F ６ The method according to claim 10, selected from the group consisting of ), and combinations thereof.

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