A method for forming a patterned structure on a semiconductor using a hydrofluorocarbon compound containing oxygen and iodine, and a method for modifying the surface of a patterned mask layer.

Abstract

The method includes reacting a silicon-containing film having a silicon-containing layer deposited on the substrate with a patterned mask layer deposited on the silicon-containing layer in a chamber containing the substrate, the silicon-containing film having a silicon-containing layer deposited on the patterned mask layer, with a compound of formula C n H x F y I z O e wherein 0≦n≦10, 0≦x≦21, 0≦y≦21, 1≦z≦4, and 1≦e≦2; activating a plasma to generate an activated etching compound containing oxygen and iodine; and allowing an etching reaction to proceed between the activated etching compound containing oxygen and iodine and the silicon-containing film to selectively etch the silicon-containing film from the patterned mask layer, thereby forming a patterned structure.

Description

[Technical Field]

[0001] Cross-reference of related applications This application claims priority under U.S. Patent Application No. 17 / 555,094, filed on 17 December 2021 under 119(a) and (b) of the U.S. Patent Act, the entire contents of which are incorporated herein by reference.

[0002] The present invention relates to a method for etching a silicon-containing film to form a patterned structure, particularly formula C n H x F y I z O e The present invention relates to a method for etching a silicon-containing film on a patterned mask layer to form a patterned structure using an oxygen-iodine-containing compound having (wherein 0≦n≦10, 0≦x≦21, 0≦y≦21, 1≦z≦4, and 1≦e≦2), thereby doping the patterned mask layer with iodine derived from iodide ions generated from the activated etching compound containing oxygen and iodine, thereby reinforcing, strengthening, or minimizing damage to the patterned mask layer. [Background technology]

[0003] In the semiconductor industry, etching of stacks of multiple SiO / SiN or SiO / polysilicon (p-Si) layers is crucial for 3D NNDs. See, for example, U.S. Patent Application Publication No. 2011 / 0180941 to Samsung Electronics Co., Ltd. An etchant with high selectivity between the mask and the layers to be etched is essential. Furthermore, the etched structure should have a straight, distortion-free vertical profile and low line etch roughness (LER).

[0004] Standard hydrofluorocarbons used for etching silicon oxide are cC4F8 and C4F6, which are combinations of an oxidizing agent (e.g., O2) and a noble gas (e.g., Ar, Kr, Xe). For etching silicon nitride, hydrogen-containing fluorocarbons such as CHF2, CHF3, and CH3F are usually mixed with the above gases.

[0005] However, the chemical properties of conventional etching may make it impossible to provide features such as holes or trenches with aspect ratios higher than 20:1 required for novel applications (e.g., 3DNAND), at least due to insufficient deposition of etching-resistant polymers on the sidewalls during the plasma etching process. x F y - The polymer (where x is in the range of 0.01 to 1 and y is in the range of 0.01 to 4) may be affected by etching. As a result, the etched pattern may not be perpendicular, and the etched structure may exhibit distortion, dimensional changes, pattern collapse, and / or increased roughness.

[0006] Distortion can result from etching of the sidewalls of the mask layer, which is often made of amorphous carbon (aC) material. aC material can be etched by oxygen radicals in the plasma, which can cause an increase in the mask's openings and result in a distorted or angled / curved etched structure.

[0007] Carbonyl-containing compounds are used as etching gases for etch-back, and / or the decomposition of carbonyl-containing compounds is disclosed. Japanese Patent No. 3291885 B2 by Y. Toshiharu discloses a dry etching method for embedding connection holes with good flatness by etch-back of a blanket CVD tungsten layer using carbonyl fluoride compound gases such as COF2, COFCl, COFBr, COFI, and (COF)2. Further, as general gases for the F source, F-based gases such as SF6, NF3, CF4, ClF3, XeF2, and F2 are used. U.S. Patent Application Publication No. 2006 / 0140836 A1 by O. Masakazuifco discloses a process for decomposing and detoxifying a fluorine compound having iodine in the molecule. The fluorine compounds include compounds such as C2F5IO and C2F4I2O. International Publication No. 2009 / 019219 pamphlet by Uenveren et al. discloses a method for etching SiO2 for self-aligned contacts using hydrofluorocarbons. Although C3F5IO is mentioned, the oxygen is the terminal oxygen bonded to carbon, and no examples of supporting etching are disclosed.

[0008] To maximize the selectivity to the hard mask and achieve the high aspect ratio (i.e., up to 200:1) required for current applications (e.g., contact etching or 3D NAND), it is important to minimize distortion, CD variation (top vs. bottom), twist, and incomplete etching. Further, the etching is not limited to the selectivity to the photoresist mask. a-C, SiN, p-Si, SiC or other forms of Si a C b O c H d N e It is equally important to obtain high selectivity among other materials such as materials (where a > 0; b, c, d, and e ≧ 0). Summary of the Invention Problems to be Solved by the Invention

[0009] Therefore, there is a need for an etching gas composition suitable for use in plasma etching applications that maintains selectivity and a high aspect ratio across a wide range of process conditions. [Means for solving the problem]

[0010] A method for forming a patterned structure is disclosed, and this method is: a) In a reaction chamber containing a substrate having a silicon-containing film deposited on the substrate and a patterned mask layer deposited on the silicon-containing layer, formula C n H x F y I z O e The step of introducing a vapor of an etching compound containing oxygen and iodine (wherein the formula 0≦n≦10, 0≦x≦21, 0≦y≦21, 1≦z≦4, and 1≦e≦2); b) A step of activating the plasma to produce an activated etching compound containing oxygen and iodine; and c) A step of carrying out an etching reaction between an activated etching compound containing oxygen and iodine and a silicon-containing film to selectively etch the silicon-containing film from the patterned mask layer, thereby forming a patterned structure; Includes.

[0011] The disclosed methods may include one or more of the following embodiments: Step c) includes modifying the patterned mask layer or doping the patterned mask layer with iodine derived from iodide ions produced from an activated etching compound containing oxygen and iodine; Step c) includes modifying the patterned mask layer; Step c) includes doping a patterned mask layer with iodine derived from iodide ions generated from an activated etching compound containing oxygen and iodine; Step c) includes reinforcing the patterned mask layer or doping the patterned mask layer with iodine derived from iodide ions generated from an activated etching compound containing oxygen and iodine; Step c) includes reinforcing the patterned mask layer or doping the patterned mask layer with iodine derived from iodide ions generated from an activated etching compound containing oxygen and iodine; Step c) includes minimizing damage to the patterned mask layer or doping the patterned mask layer with iodine derived from iodide ions generated from an activated etching compound containing oxygen and iodine; Step c) includes increasing the etching resistance of the patterned mask layer or doping the patterned mask layer with iodine derived from iodide ions generated from an activated etching compound containing oxygen and iodine; Step c) includes a step of increasing the etching selectivity for the underlying layers of the substrate while forming a patterned structure on the substrate; The step further includes introducing an inert gas into the reaction chamber; • The inert gas is selected from the group consisting of He, Ar, Xe, Kr, Ne, and N2; • The inert gas is Ar; • Mix an etching compound containing oxygen and iodine with an inert gas before introducing it into the chamber to produce a mixture; • An etching compound containing oxygen and iodine is introduced separately from the inert gas; • Inert gas is continuously introduced, and an etching compound containing oxygen and iodine is introduced in pulses; • The inert gas accounts for approximately 0.01% v / v to approximately 99.9% v / v of the total volume of the etching compound vapor containing oxygen and iodine and the inert gas; • The inert gas accounts for approximately 90% v / v to 99% v / v of the total volume of the etching compound vapor containing oxygen and iodine, and the inert gas. The step optionally further includes introducing an oxidizing agent into the reaction chamber; The oxidizing agent is 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; • Mix an etching compound containing oxygen and iodine with an oxygen-containing gas to produce a mixture before introducing it into the chamber; • An etching compound containing oxygen and iodine is introduced separately from the oxygen-containing gas; • Continuously introduce an oxygen-containing gas and an etching compound containing oxygen and iodine; • The oxygen-containing gas accounts for approximately 0.01% v / v to approximately 99.9% v / v of the total volume of the etching compound containing oxygen and iodine, and the oxygen-containing gas. • The oxygen-containing gas accounts for approximately 0.01% v / v to approximately 10% v / v of the total volume of the etching compound containing oxygen and iodine, and the oxygen-containing gas. • Etching compounds containing oxygen and iodine are hydrofluorocarbon compounds; • An etching compound containing oxygen and iodine is a hydrofluorocarbon containing oxygen and iodine; • Etching compounds containing oxygen and iodine are organofluorine compounds; • Etching compounds containing oxygen and iodine are fluorine-containing hydrocarbon compounds; • Etching compounds containing oxygen and iodine are fluorocarbon compounds; • Etching compounds containing oxygen and iodine do not contain hydrogen; • Etching compounds containing oxygen and iodine contain hydrogen; • Etching compounds containing oxygen and iodine contain fluorine; • Etching compounds containing oxygen and iodine do not contain fluorine; The etching compounds containing oxygen and iodine are C3F7IO and its isomers; The etching compound containing oxygen and iodine is C3F7IO, 2-iodo-1-(trifluoromethoxy)tetrafluoroethane (CAS number: 1561-52-0); The etching compound containing oxygen and iodine is C3F7IO, 1,1,1,2-tetrafluoro-2-iodo-2-(trifluoromethoxy)ethane (CAS number: 139604-89-0); The etching compound containing oxygen and iodine is C3F7IO, 1,2,2,2-tetrafluoro-1-trifluoromethoxy-1-iodoethane (CAS number: 69066-98-4); The etching compound containing oxygen and iodine is C3F7IO, 1,1,1,2,2,3,3,3-heptafluoro-3-iodocyl-propane (CAS number: 180613-10-9); The etching compounds containing oxygen and iodine are C3F6I2O, C3F5I3O, C3F4I4O, and their isomers; • Etching compounds containing oxygen and iodine include C3F7IO, C3F6I2O, C3F5I3O, C3F4I4O, C4F9IO, C4F8I2O, C4F7I3O, C4F6I4O, and C5F 11 IO, C5F 10 I2O, C5F9I3O, C5F8I4O, C6F 13 IO, C6F 12 I2O, C6F 11 I3O, C6F 10 I4O, C7F 15 IO, C7F 14 I2O, C7F 13 I3O, C7F 12 I4O, C8F 17 IO, C8F 16 I2O, C8F 15 I3O, C8F 14 I4O, C9F 19 IO, C9F 18 I2O, C9F 17 I3O, C8F 16 I4O, C 10 F 21 IO, C 10 F 20 I2O, C10 F 19 I3O, C 10 F 18 I4O and their isomers; • Etching compounds containing oxygen and iodine include C4F9IO, C4F9IO, and C5F 11 IO, C5F 11 IO, C6F 13 IO, C7F 15 IO, C8F 17 IO, C9F 19 IO, C 10 F 21 IO, and their isomers; Etching compounds containing oxygen and iodine include C3HF6IO, C3HF5I2O, C3HF4I3O, C3HF3I4O, C4HF8IO, C4HF7I2O, C4HF6I3O, C4HF5I4O, and C5HF 10 IO, C5HF9I2O, C5HF8I3O, C5HF7I4O, C6HF 12 IO, C6HF 11 I2O, C6HF9I3O, C6HF8I4O, C7HF 14 IO, C7HF 13 I2O, C7HF 12 I3O, C7HF 11 I4O, C8HF 16 IO, C8HF 15 I2O, C8HF 14 I3O, C8HF 10 I4O, C9HF 18 IO, C9HF 17 I2O, C9HF 16 I3O, C9HF 15 I4O, C 10 HF 20 IO, C 10 HF 19 I2O, C 10 HF 18 I3O, C 10 HF 17 I4O and their isomers; • An etching compound containing oxygen and iodine, activated by plasma, reacts with a silicon-containing film to form volatile byproducts; • Volatile by-products are removed from the reaction chamber; • The silicon-containing film contains oxygen, nitrogen, carbon, hydrogen, or a combination thereof; • The silicon-containing film optionally contains dopants such as B, C, P, As, Ga, In, Sn, Sb, Bi and / or Ge, or 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 (wherein a>0 and b, c, d, and e≧0), the structure includes alternating layers of SiO and SiN(ONON), or alternating layers of SiO and p-Si(OPOP); • Silicon-containing film, SiO x N y H z C k (In the equation, 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 patterned 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 patterned 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 patterned mask layer is an amorphous carbon (aC) layer; The patterned 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; Alternating layers are selectively etched from the patterned 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 the doped carbon layer; • The silicon oxide layer is selectively etched from the patterned 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 from the patterned 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 from the patterned mask layer; • The polysilicon layer is selectively etched from the aC layer; • The polysilicon layer is selectively etched from the doped carbon layer; The silicon-containing film is selectively etched from the aC layer, the doped aC layer, the photoresist layer, the anti-reflective layer, or the organic planarization layer; The silicon oxide layer is selectively etched from the aC layer, doped aC layer, photoresist layer, anti-reflective layer, or organic planarization layer; • Etching compounds containing oxygen and iodine etch both the silicon oxide layer and the silicon nitride layer at a high etching rate; An etching compound containing oxygen and iodine, which plasma-etches alternating layers of SiO and SiN(ONON), exhibits selectivity of approximately 1:2 to 2:1 with respect to the SiO layer versus the SiN layer; An etching compound containing oxygen and iodine, which plasma-etches alternating layers of SiO and SiN(ONON), exhibits approximately 1:1 selectivity with respect to the SiO layer versus the SiN layer; An etching compound containing oxygen and iodine, which plasma-etches alternating layers of SiO and p-Si (OPOP), exhibits selectivity of approximately 1:2 to 2:1 with respect to the SiO layer versus the p-Si layer; An etching compound containing oxygen and iodine, which plasma-etches alternating layers of SiO and p-Si (OPOP), exhibits approximately 1:1 selectivity for the SiO layer versus the p-Si layer; The selectivity of an oxygen- and iodine-containing etching compound for plasma etching SiO2 on a patterned mask layer is approximately 70% higher than the selectivity of C4F6, a benchmark gas for etching SiO2 on a patterned mask layer at a similar etching rate; The patterned mask layer is a carbon-containing layer, an amorphous carbon layer, a doped amorphous carbon layer, a photoresist layer, an anti-reflective layer, an organic planarization layer, or a combination thereof; • An activated etching compound containing oxygen and iodine selectively etches the silicon-containing film from the landing layer located at the bottom of the film being etched; • The landing layer is an embedded landing layer located at the bottom of the structure being etched; • The landing layer is the etching stop layer; • The landing layer is a silicon layer; • The landing layer is a metallic layer; The landing layer is a tungsten metal world line with a 3D NAND structure and / or another metal such as W, Cu, Al, Ru, Pt, Ti, Ta, Ni, Co, Mo, Mn, Nb, Cr, Rh, Pd, Ir, V, Au, Ag, or a combination thereof; The landing layer is a metallic layer selected from W, Cu, Al, Ru, Pt, Ti, Ta, Ni, Co, Mo, Mn, Nb, Cr, Rh, Pd, Ir, V, Au, Ag, or a combination thereof; • The landing layer is a metal oxide layer or a metal nitride layer; The landing layer is a metal oxide layer selected from AlO, WO, HfO, TiO, TaO, InO, WO, CrO, RuO, CoO, MoO, ZrO, SnO, or a combination thereof; The landing layer is a metal nitride layer selected from TiN, TaN, HfN, AlN, WN, MoN, NiN, NbN, CrN, RuN, CoN, ZrN, SrN, or a combination thereof; • 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; This further includes introducing additional etching gas into the reaction chamber; • 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), C4F9I, 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), 1,1,2,2-tetrafluorocyclobutane (C4H4F4), and cis-1,1,2,2,3,4-hexafluorocyclobutane (cis-C4H2F6), or combinations thereof, selected from the group; • Introduce an etching compound containing oxygen and iodine separately from the additional etching gas; • Add an additional etching gas of approximately 0.01% v / v to approximately 99.99% v / v to the etching compound containing oxygen and iodine; The patterned structures formed on the silicon-containing film have an aspect ratio of approximately 1:1 to approximately 200:1; • Iodine doping concentration increases by 0.1% to 99.9% across the entire deposited film; • Apply RF power to activate the plasma; • The plasma is activated by RF power ranging from approximately 25W to approximately 100,000W; • The etching pressure is in the range of approximately 1 mTorr to 10 Torr; The etching pressure is 30 mTorr; • Introduce the iodine-containing etching compound at a flow rate ranging from approximately 0.1 sccm to approximately 1 slm; • Maintain the substrate at a temperature within the range of approximately -196°C to approximately 500°C.

[0012] A method for forming a patterned structure is disclosed, and this method is: a) Introducing vapor of C3F7IO into a reaction chamber containing a substrate having a silicon-containing film deposited on the substrate and a patterned mask layer deposited on the silicon-containing layer; b) Activating the plasma to generate activated C3F7IO; and c) Proceeding an etching reaction between activated C3F7IO and a silicon-containing film to selectively etch the silicon-containing film from the patterned mask layer, thereby forming a patterned structure; The disclosed methods may include one or more of the following embodiments: Step c) includes modifying the patterned mask layer by doping it with iodine derived from iodide ions generated from an activated etching compound containing oxygen and iodine; Step c) includes modifying the patterned mask layer; Step c) includes doping a patterned mask layer with iodine derived from iodide ions generated from an activated etching compound containing oxygen and iodine; • Iodine doping concentration increases by 0.1% to 99.9% across the entire deposited film; The selectivity of an oxygen- and iodine-containing etching compound for plasma etching SiO2 on a patterned mask layer is approximately 70% higher than the selectivity of C4F6, a benchmark gas for etching SiO2 on a patterned mask layer at a similar etching rate.

[0013] A method for modifying the surface of a substrate is disclosed, and this method is: In a reaction chamber containing a substrate having a silicon-containing film deposited on the substrate and a patterned mask layer deposited on the silicon-containing layer, formula C n Hx F y I z O e Introducing a vapor of an etching compound containing oxygen and iodine (wherein 4≦n≦10, 0≦x≦21, 0≦y≦21, 1≦z≦4, and 1≦e≦2); Etching a silicon-containing film from a patterned mask layer using an activated etching compound containing oxygen and iodine, formed by activating a plasma, to form a patterned structure; Includes; Iodine derived from iodide ions generated from an activated etching compound containing oxygen and iodine is doped into the patterned hard mask layer while forming a patterned structure on the substrate, thereby strengthening the patterned mask layer and minimizing damage to the patterned mask. The disclosed method may include one or more of the following embodiments: The etching compounds containing oxygen and iodine are C3F7IO and its isomers; • Iodine doping concentration increases by 0.1% to 99.9% across the entire deposited film; The selectivity of an oxygen- and iodine-containing etching compound for plasma etching SiO2 on a patterned mask layer is approximately 70% higher than the selectivity of C4F6, a benchmark gas for etching SiO2 on a patterned mask layer at a similar etching rate.

[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. These include:

[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 term "ambient temperature" refers to an ambient temperature of approximately 20°C to 25°C.

[0019] The term "substrate" refers to one or more materials on which a process is carried out. A substrate may also refer to a wafer having one or more materials on which a process is carried out. A substrate may be any suitable wafer used in the manufacture of semiconductors, photovoltaics, flat panels, or liquid crystal display thin-film transistor (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, SiC, SiCN, SiOCN, SiCOH, etc.), metal-containing layers (e.g., copper, cobalt, ruthenium, tungsten, manganese, 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 organic material. The substrate may include an oxide layer used as a dielectric material in MEMS, 3D NAND, MIM, dynamic random-access memory (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.) or a nitride-based film used as an electrode (e.g., TaN, TiN, NbN). Those skilled in the art will recognize that the terms “film” or “layer” as used herein refer to the thickness of any material arranged or spread on a surface, which may be a trench or a line. Throughout this specification and the claims, the wafer and any associated layers thereon are referred to as the substrate.

[0020] The terms "wafer" or "patterned wafer" refer to a wafer having a stack of silicon-containing films on a substrate and a patterned hard mask layer on the stack of silicon-containing films formed for pattern etching.

[0021] The term "pattern etching" or "patterned etching" refers to etching non-planar structures, such as patterned mask layers on a stack of silicon-containing films.

[0022] As used herein, the terms “etch” or “etch” mean the removal of material by a plasma-based chemical vapor reaction between an etching gas and a substrate, and refer to isotropic 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 produce lateral or horizontal etching profiles on the substrate. Isotropic etching processes produce 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 produce vertical etching profiles on the substrate. The plasma etching process creates vertical vias, apertures, trenches, channel holes, gate trenches, stepped contacts, capacitor holes, contact holes, slit etchings, self-aligned contacts, self-aligned vias, supervias, and other features on the substrate.

[0023] The term "mask" refers to a layer that resists etching. The mask layer can be disposed on top of the layer to be etched. The mask layer also refers to a hard mask layer. The mask layer may be a carbon-containing layer, a silicon-containing layer, a metal-containing layer, a metal oxide-containing layer, or a metal nitride-containing layer.

[0024] The term "etch stop" means a layer below the layer to be etched that protects the underlying layer.

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

[0026] The term "aspect ratio" means the ratio of the height of a trench (or via) to the width of the trench (or diameter of the via).

[0027] The term "selectivity" means the ratio of the etching rate of one material to the etching rate of another material. The term "selective etching" or "selectivity etching" means etching one material over another material, or in other words, that the etching selectivity between two materials is greater than or less than 1:1.

[0028] When the term "independently" is used with respect to the description of R groups, it should be understood to mean that the R group in question is 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) where 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 R 3It may be the same as, but does not need to be the same as, the same. Furthermore, unless otherwise specified, it should be understood that the values ​​of the R group are independent of each other when used in different formulas.

[0029] 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.

[0030] It should be noted that the terms “etching compound” and “etching gas” may be used interchangeably within this specification. It is understood that an etching compound may correspond to or be related to an etching gas, and that an etching gas may mean an etching compound.

[0031] The terms "via," "aperture," "trench," and "hole" may be used interchangeably and generally refer to openings in interlayer insulation.

[0032] 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.

[0033] 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.).

[0034] The unique Chemical Abstract Service (CAS) Registry Number (i.e., "CAS") assigned by the Chemical Abstract Service is provided to help better identify the disclosed molecule.

[0035] Note that silicon-containing films such as silicon nitride and silicon oxide are listed throughout the specification and claims without indicating their proper 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 ) layers; silicon oxide (Si n O m ) layers; or mixtures thereof, 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. 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, SiN and SiO in the following specification represent Si k N l and Si n O m containing layers, respectively. The silicon-containing film can also be a silicon-based dielectric material such as an organic-based or silicon oxide-based low dielectric constant dielectric material having SiOCH, such as the Black Diamond II or III material by Applied Materials, Inc. The silicon-containing film can include SiaObCcNdHe where a, b, c, d, e are in the range of 0.1 to 6. The silicon-containing film can also include dopants such as B, C, P, As, Ga, In, Sn, Sb, Bi, and / or Ge.

[0036] In this specification, a range may be expressed as approximately from one specific value and / or approximately from 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 from another specific value.

[0037] Any reference in this specification to “one embodiment” or “a particular embodiment” means that certain features, structures, or characteristics described in relation to an embodiment may be included in at least one embodiment of the present invention. The phrase “in one embodiment” appearing in various places in this specification does not necessarily refer to the same embodiment, and another or alternative embodiment is not necessarily mutually exclusive with other embodiments. The same applies to the term “implementation.”

[0038] For a further understanding of the characteristics and objectives 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]

[0039] [Figure 1a] Figure 1a is a cross-sectional view of an exemplary layer in a 3D NAND stack. [Figure 1b] Figure 1b is a cross-sectional view of a model layer in a 3D NAND stack, showing polymer deposited on the sidewalls during etching of the 3D NAND stack. [Figure 1c] Figure 1c is a cross-sectional view of a typical layer in a 3D NAND stack, showing particles generated during alternating SiO / SiN layer etching of the 3D NAND stack. [Figure 1d] Figure 1d is a cross-sectional view of an exemplary layer in a 3D NAND stack, showing selective etching of SiN exposed on the sidewalls within the 3D NAND stack. [Figure 2] Figure 2 shows a cross-sectional view of a typical layer of a DRAM stack. [Figure 3a]Figure 3a is a cross-sectional view of an exemplary layer showing a photoresist pattern on the SiO insulating layer around a typical transistor device region for creating a transistor structure. [Figure 3b] Figure 3b is a cross-sectional view of the exemplary layer shown in Figure 3a after etching of the SiO insulating layer. [Figure 4] Figure 4 shows the etching rate (ER) and selectivity of C3F7IO on four different substrates. [Figure 5a] Figure 5a shows the depth-direction X-ray photoelectron spectroscopy (XPS) profile of an amorphous carbon pattern mask etched with C3F7IO, comparing atomic concentration (%) with Ar etching time. [Figure 5b] Figure 5b is a magnified view of the depth-direction X-ray photoelectron spectroscopy (XPS) profile showing atomic concentration (%) versus Ar etching time for an amorphous carbon pattern mask etched with C3F7IO, highlighting the iodine and oxygen doping of the mask. [Figure 6a] Figure 6a shows the depth profile of an X-ray photoelectron spectroscopy (XPS) scan of a silicon substrate etched with C3F7IO, comparing atomic concentration (%) with Ar etching time. [Figure 6b] Figure 6b is a magnified view of the depth-direction profile of an X-ray photoelectron spectroscopy (XPS) scan showing atomic concentration (%) versus Ar etching time for a silicon substrate etched with C3F7IO, highlighting the doping by oxygen in the mask. [Figure 7] Figure 7 shows X-ray photoelectron spectroscopy (XPS) results for fluorine (F1s) and iodine I3d peaks of an amorphous carbon pattern mask etched with C3F7IO, with counts per second against binding energy (eV). [Figure 8] Figure 8 shows the etching rate (ER) and selectivity of C4F6 on four different substrates as a function of oxygen flow rate. [Modes for carrying out the invention]

[0040] A method for plasma etching semiconductor structures such as trenches, nanolines, nanopillars, channel holes, gate trenches, contacts, stepped contacts, capacitor holes, contact holes, high aspect ratio structures, 3D NAND structures, DRAM structures, slit trenches, self-aligned contacts, vias, self-aligned vias, and supervias in silicon-containing films is disclosed. The disclosed method involves i) placing a substrate having a film deposited on the substrate and a patterned mask layer deposited on the film into a reaction chamber containing a material containing the formula C a H b F c I d O e The process includes: 1) introducing a vapor of an etching compound containing oxygen (including alkoxy) and iodine having (wherein 0≦a≦10, 0≦b≦21, 0≦c≦21, 1≦d≦4, and 1≦e≦2); and 2) activating a plasma to generate an activated etching compound containing oxygen and iodine that can etch a film on a patterned mask layer from a substrate. While the film is etched, the patterned mask layer is doped with iodine derived from iodide ions generated from the activated etching compound containing oxygen and iodine, thereby reinforcing or strengthening the patterned mask layer and minimizing damage to it. The film here may be a silicon-containing film.

[0041] As shown in the following example, the iodide ions in the disclosed oxygen-iodine-containing etching compounds dissociate from the compound at low energy (eV) (i.e., <20 eV). As a result, the applicants believe that the disclosed etching compounds can be used in dry plasma etching processes that cause less damage to the underlying substrate because they are viable at lower plasma energies. For example, because lower plasma energies cause less damage to porous, low-dielectric-constant materials surrounding the etching site, the disclosed oxygen-iodine-containing etching compounds may be particularly suitable for low-dielectric-constant etching processes where damage is a particular concern. The reduced damage to low-dielectric-constant materials may be due to the reduced generation of UV photons and F radicals provided by the oxygen-iodine-containing etching compounds. The disclosed oxygen-iodine-containing etching compounds can also prevent loss of critical dimensions and reduce low-dielectric-constant surface roughness. In addition, molecules with two iodine atoms enhance these advantages, allowing for increased doping levels and preservation of the mask layer without damaging the underlying layer.

[0042] Iodine (10.5 eV) has a lower ionization threshold than fluorine (17.4 eV) and inert gases: Ar (15.8 eV), Xe (12.1 eV), and Kr (14 eV). Therefore, iodine can be ionized more easily by plasma than fluorine, and iodine-containing etching compounds can increase plasma density. Iodine is a heavy element (mass 127 amu) and can also exhibit similar behavior to inert gases in plasma (such as Kr at 88 amu and Xe at 131 amu), accelerating toward the wafer. During etching of high aspect ratio structures, many ions cannot reach the bottom of the trench because the energy of the ions weakens the deeper they penetrate. However, heavy iodine ions can be accelerated toward the wafer by the voltage applied during the plasma etching process and penetrate deeply, enabling etching of deep, patterned structures with high aspect ratios. The low ionization threshold of fluorine is useful in maintaining it as a neutral chemical species. As a result, fluorine is typically involved in the etching process through chemical reactions. Iodine exhibits lower chemical reactivity than fluorine and is ionized during the plasma etching process, impacting the surface. Also, the bond energy of CI is lower than that of CF, and thus CI bonds are more easily broken in the plasma compared to CF bonds. Therefore, iodide ions can be easily doped into the aC mask layer. Because iodine is a heavy element, it is easier to implant into the mask layer and penetrates deeper than lighter elements. In addition, due to the fact that CI bonds are weak and the ionization threshold of iodine is low, the atmospheric lifetime of iodine-containing etching compounds is short or negligible, and therefore this is an excellent candidate for reducing the global warming potential (GWP) caused by perfluorocarbon compounds. The average bond energies of various bonds are shown in Table 1 (from Huheey et al., Inorganic Chemistry, 4th ed. (1993)).

[0043] [Table 1]

[0044] As mentioned in the comparative examples below, iodide ions dissociate from the disclosed etching compounds at low eV (i.e., <20 eV). However, it is possible that iodide ions may be implanted into mask features such as surfaces and / or bodies / bulks. This implantation may help strengthen the mask features, minimize damage, improve etching resistance, and maintain shape and profile during the etching process. After using the disclosed oxygen and iodine-containing etching compounds, the composition of the pattern mask is modified, as shown in the examples below. The applicants believe that iodide ions are incorporated into the bulk of the pattern mask layer by modifying the surface and increasing bridging with the organic mask layer (such as an amorphous carbon mask). Due to iodide ion doping, as well as bridging between carbon, iodine, hydrogen, and fluorine atoms, preferably between carbon and iodine, the density of the pattern mask layer increases, thereby making the pattern mask layer stronger. In the following examples, the strengthening effect and improved etching resistance by iodide ions are demonstrated by showing that etching with an iodine-containing etching compound results in a lower etching rate of the pattern mask layer compared to etching with conventional etching gases such as cC4F8 and C4F6.

[0045] The most important aspect of this invention is to understand the effect of iodine on amorphous carbon. Iodine helps preserve the aC mask during etching by modifying and doping the surface of the aC layer. It is also useful in minimizing damage by strengthening the patterned mask layer. During the plasma process, the disclosed iodine-containing gas or precursor may be generated in the following forms: 1) iodide ions (I + , I - );2) Iodine radical (I·);3) Iodine-containing polymer ion( + C x H y I z F d O e , - C x Hy I z F d O e ); and 4) Iodine-containing polymer radicals (·C x H y I z F d O e The above iodine-containing species can be deposited on the carbon-containing layer by controlling the bias power. Furthermore, these chemical forms are deposited as polymer layers that can enhance the EUV absorption of the layer during the patterning process. Doping the carbon matrix with iodine ions and radicals can enhance the EUV absorption of the layer during patterning processes such as resistless lithography. The iodine-containing polymer and / or iodine-doped carbon layers thus formed can be used to enhance the etching selectivity for layers to be etched, such as silicon-containing layers.

[0046] The disclosed etching compound containing oxygen and iodine is, C a H b F c I d O e (In the formula, 0 ≤ a ≤ 10, 0 ≤ b ≤ 21, 0 ≤ c ≤ 21, 1 ≤ d ≤ 4, and 1 ≤ e ≤ 2) It holds.

[0047] If the disclosed etching compound containing oxygen and iodine contains one oxygen atom (i.e., e=1), then the disclosed etching compound containing oxygen and iodine is given by formula C a H b F c I d O (In the formula, 0 ≤ a ≤ 10, 0 ≤ b ≤ 21, 0 ≤ c ≤ 21, and 1 ≤ d ≤ 4.) It has oxygen, which links two carbon atoms together, bridging the space between them.

[0048] If the disclosed etching compound containing oxygen and iodine does not contain hydrogen (i.e., b=0), then the disclosed etching compound containing oxygen and iodine is given by formula C a F c I d O e (In the formula, 0 ≤ a ≤ 10, 0 ≤ c ≤ 21, 1 ≤ d ≤ 4, and 1 ≤ e ≤ 2.) It has the following characteristics. In this case, when a=3, the disclosed etching compound containing oxygen and iodine is of formula C3F c I d O e (wherein the formula, 1 ≤ d ≤ 4, c ≤ 10-d, and 1 ≤ e ≤ 2). Examples of etching compounds containing oxygen and iodine of C3 that do not contain H include C3F7IO, C3F6I2O, C3F5I3O, C3F4I4O and their isomers.

[0049] Examples of etching compounds containing oxygen and iodine that do not contain H include C3F7IO, C3F6I2O, C3F5I3O, C3F4I4O, C4F9IO, C4F8I2O, C4F7I3O, C4F6I4O, and C5F 11 IO, C5F 10 I2O, C5F9I3O, C5F8I4O, C6F 13 IO, C6F 12 I2O, C6F 11 I3O, C6F 10 I4O, C7F 15 IO, C7F 14 I2O, C7F 13 I3O, C7F 12 I4O, C8F 17 IO, C8F 16 I2O, C8F 15 I3O, C8F 14 I4O, C9F 19 IO, C9F 18 I2O, C9F 17 I3O, C8F 16 I4O, C 10 F 21 IO, C 10 F 20 I2O, C10 F 19 I3O, C 10 F 18 Examples include I4O and its isomers. Here, the oxygen connects two carbon atoms, bridging the space between them.

[0050] A substance containing one oxygen atom and one iodine atom, but without H, has the general formula C a F 2a+1 Exemplary disclosed etching compounds having IO (where 0 ≤ a ≤ 10) are listed in Table 2. These molecules are commercially available or can be synthesized by methods known in the art. Their structural formulas, CAS numbers, and boiling points are included in Table 2. A general formula C containing oxygen and iodine but without H. a F 2a+1 The disclosed etching compounds having IO (where 3 ≤ a ≤ 10) may also include their isomers. More specifically, oxygen links two carbons, bridging the space between them.

[0051] [Table 2]

[0052] The disclosed etching compounds containing oxygen and iodine include silicon oxide (SiO), silicon nitride (SiN), pure silicon (Si), such as crystalline Si, polysilicon (p-Si or polycrystalline Si), or amorphous silicon, low dielectric constant SiCOH, SiOCN, SiC, SiON, and Si a O b H c C d N e Suitable for etching silicon-containing films containing layers of (wherein a>0 and b, c, d, and e≧0), or combinations thereof. The silicon-containing film may also contain alternating layers of silicon oxide and silicon nitride (ONON) or alternating layers of silicon oxide and polysilicon (OPOP). The silicon-containing film may also contain dopants such as B, C, P, As, Ga, In, Sn, Sb, Bi, and / or Ge.

[0053] When the disclosed etching compound containing oxygen and iodine contains H, it is possible to improve the etching rate of SiO and SiN while maintaining high selectivity for the mask layer, but is not limited to this. When b=1, the disclosed etching compound containing oxygen and iodine having one H is given by formula C a HF c I d O e (wherein the formula, 3≦a≦10, 0≦c≦20, 1≦d≦4, y+z≦2n+1, and 1≦e≦2). Exemplary compounds having one H include C3HF6IO, C3HF5I2O, C3HF4I3O, C3HF3I4O, C4HF8IO, C4HF7I2O, C4HF6I3O, C4HF5I4O, and C5HF 10 IO, C5HF9I2O, C5HF8I3O, C5HF7I4O, C6HF 12 IO, C6HF 11 I2O, C6HF9I3O, C6HF8I4O, C7HF 14 IO, C7HF 13 I2O, C7HF 12 I3O, C7HF 11 I4O, C8HF 16 IO, C8HF 15 I2O, C8HF 14 I3O, C8HF 10 I4O, C9HF 18 IO, C9HF 17 I2O, C9HF 16 I3O, C9HF 15 I4O, C 10 HF 20 IO, C 10 HF 19 I2O, C 10 HF 18 I3O, C 10 HF 17 Examples include I4O and its isomers.

[0054] The disclosed etching compound containing oxygen and iodine, having two hydrogens when b=2, is given by formula C a H2F c I d O e(wherein the formula, 3≦a≦10, 0≦c≦19, 1≦d≦4, c+d≦2n, and 1≦e≦2) are given. Examples of compounds include the following:

[0055] The disclosed etching compound containing oxygen and iodine, having three hydrogen atoms when b=3, is given by formula C a H3F c I d O e (The formula has the following properties: 3≦a≦10, 0≦c≦19, 1≦d≦4, c+d≦2n-1, and 1≦e≦2).

[0056] The disclosed etching compound containing oxygen and iodine, having four hydrogen atoms when b=4, is given by formula C a H3F c I d O e (The formula has the following properties: 3≦a≦10, 0≦c≦19, 1≦d≦4, c+d≦2n-2, and 1≦e≦2).

[0057] The applicants believe that molecules with three or more carbon atoms can provide better etching rates and sidewall protection than molecules with fewer than three carbon atoms during the etching process, such as a straight profile, no curvature, no tapering, no twisting, no incomplete etching, and no variation in the critical dimensions from top to bottom of the etched structure. The applicants also believe that molecules with four or more carbon atoms can provide a straighter profile than molecules with fewer than four carbon atoms, without curvature, tapering, twisting, and incomplete etching, or variation in the critical dimensions from top to bottom of the etched structure. The applicants believe that molecules with three or more carbon atoms are preferable for sidewall protection because they generate a thicker passivation layer.

[0058] The disclosed oxygen-iodine-containing etching compounds may provide high selectivity for mask layers, photoresists, etching stop layers, and device channel materials, but may not provide profile distortion in high aspect ratio structures (HARs) such as those with aspect ratios in the range of 1:1 to 200:1, including DRAMs, 3D NAND memories, and logic structures. Instead, the disclosed oxygen-iodine-containing etching compounds may provide high selectivity for mask layers or silicon-containing films, such as those with aspect ratios in the range of 1:1 to 200:1, in contact etching applications.

[0059] The disclosed oxygen-iodine-containing etching compounds can offer countless selectivity for a wide range of etching process conditions. In this specification, selectivity refers to the etching rate ratio of two different layers. For example, the selectivity for an SiO layer versus an aC layer is the etching rate of SiO divided by the etching rate of the aC layer. The disclosed oxygen-iodine-containing etching compounds can provide improved selectivity between the silicon-containing film and the mask material, reduced damage to channel regions, improved critical dimensional uniformity, and reduced profile distortion such as curvature, twisting, tapering, notches, and undercuts, and can maintain the same critical dimensions and pattern high aspect ratio structure arcing from top to bottom of the etched structure. The disclosed oxygen-iodine-containing etching compounds can etch through alternating layers of p-Si, SiO, and / or SiN to obtain a vertical etching profile (i.e., exhibiting selectivity in the range of 2:1 to 1:2 between the alternating layers). The plasma of the disclosed oxygen- and iodine-containing etching compound etches alternating SiO and SiN(ONON) layers with selectivity of about 1:2 to about 2:1 with respect to the SiO layer versus the SiN layer. Preferably, the plasma of the disclosed oxygen- and iodine-containing etching compound etches alternating SiO and SiN(ONON) layers with selectivity of about 1:1 with respect to the SiO layer versus the SiN layer.

[0060] The disclosed etching compounds containing oxygen and iodine 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 etching compounds containing oxygen and iodine contain less than 5% by volume of trace gaseous impurities, including impurity gases such as N2 and / or H2O and / or CO2 in a volume of less than 150 ppm. 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.

[0061] The disclosed etching compounds containing oxygen and iodine 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 gas or liquid distillation to remove the isomers and may provide better process repeatability.

[0062] Alternatively, the disclosed etching compounds containing oxygen and iodine may contain 0.01% v / v to 99.99% v / v of their isomers, particularly if the isomer mixture provides improved process parameters or if the isolation of the target isomer is difficult or too costly. For example, the disclosed etching compounds containing oxygen and iodine may contain about 50% v / v to about 75% v / v of 2-iodo-1-(trifluoromethoxy)tetrafluoroethane, about 25% v / v to about 50% v / v of 1,1,1,2-tetrafluoro-2-iodo-2-(trifluoromethoxy)ethane, and about 25% v / v to about 50% v / v of 1,2,2,2-tetrafluoro-1-trifluoromethoxy-1-iodoethane. The mixture of isomers can also reduce the need for two or more gas lines to the reaction chamber.

[0063] Some of the disclosed etching compounds containing oxygen and iodine are gaseous at room temperature and pressure. With respect to non-gaseous (i.e., liquid or solid) compounds, their gaseous form can be produced by evaporating the compound by a conventional evaporation step such as direct evaporation, or by bubbling with an inert gas (such as N2, Ar, or He). Non-gaseous compounds may be supplied in liquid form to an evaporator to evaporate them before introducing them into a reactor.

[0064] The disclosed oxygen-iodine-containing etching compounds are suitable for plasma etching of semiconductor structures such as channel holes, gate trenches, stepped contacts, slits, condenser holes, contact holes, self-aligned contacts, self-aligned vias, and supervias in silicon-containing films. Because the disclosed oxygen-iodine-containing etching compounds do not induce damage, or only minimal damage, on the mask, along with good profiles of high aspect ratio structures, the disclosed oxygen-iodine-containing etching compounds are compatible not only with currently available mask materials but also with next-generation mask materials. In other words, the disclosed oxygen-iodine-containing etching compounds can create vertical etching patterns with or without minimal distortion, pattern collapse, or roughness. To achieve these properties, the disclosed oxygen-iodine-containing etching compounds may have an etching-resistant polymer layer deposited during etching to help reduce the direct effects of oxygen and fluorine radicals during the etching process. The disclosed etching compounds containing oxygen and iodine may reduce damage to p-Si or crystalline Si channels and silicon-containing structures during etching.

[0065] The disclosed oxygen- and iodine-containing etching compounds selectively etch silicon-containing layers from embedded landing layers or materials, which are metal layers located at the bottom of the structure to be etched in most applications. The disclosed oxygen- and iodine-containing etching compounds do not etch the landing layer or metal landing layer. The embedded landing layer may be an etching stop layer or a diffusion barrier layer. The material for the metal landing layer may be a tungsten metal worldline with 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, 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). The disclosed etching compounds containing oxygen and iodine cause little to no damage to the materials at the bottom of contact holes, stepped and slit-shaped structures (such as the tungsten metal worldline of the 3D NAND structure and / or other metals such as W, Cu, Al, Ru, Pt, Ti, Ta, Ni, Co, Mo, Mn, Pd, Ir, Nb, Cr, Rh, V, Au, Ag or combinations thereof), and / or etching stop layers such as metal or metal oxide or nitride layers (such as 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 combinations thereof). Those skilled in the art will recognize that barrier layers such as Ti / TiN, Ti / TiN / Ti, TiZrN, Ta / TaN, TaN / Cu / TaN, and TaN / Ru / TaN can also be composed of the aforementioned combinations of metals, metal oxides, and nitrides.The barrier may also include silicides (TiSiN, TaSiN, TiSi2, MnSiO, etc.), phosphides (CuWP, NiMoP, NiP, etc.), carbides (TaC, TaCN, WCN, etc.), borides (NiMoB, NiB, etc.), or combinations thereof. Preferably, the disclosed etching compound containing oxygen and iodine is appropriately volatile and stable during the etching process for delivery into the reactor / chamber.

[0066] Material compatibility testing is crucial to determine whether any disclosed oxygen- and iodine-containing etching compounds react with the chamber material and degrade the chamber's performance over short or long-term use. Key materials related to parts such as chambers and valves include stainless steel, aluminum, nickel, polychlorotrifluoroethylene (PCTFE), polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), PFA, PP, kalrez, viton, and other metals and polymers. Sometimes, these materials are exposed to high temperatures, e.g., above 20°C, and high pressures, e.g., above 1 atm, which can enhance their degradation. Measurement methods may include visual inspection, gravimetric measurement, measurement of changes at the nanometer scale using scanning electron microscopy (SEM), tensile strength, hardness, etc.

[0067] The disclosed oxygen- and iodine-containing etching compounds can be used to plasma-etch silicon-containing films on a substrate. 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 oxygen- and iodine-containing etching compounds may be useful in other area applications, such as different front-end (FEOL) and back-end (BEOL) etching applications. Furthermore, the disclosed etching compounds containing oxygen and iodine may be used to interconnect memory to logic on a substrate, to etch Si in 3D through-silicon via (TSV) etching applications, and in MEMS applications.

[0068] The plasma etching method includes providing a reaction chamber having a substrate placed therein. The reaction chamber may be an enclosure or chamber in any device in which the etching method is performed, including but not limited to reactive ion etching (RIE), capacitively coupled plasma (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 etchers sold under the trademark eMAX®, or the Lam Research Dual CCP reactive ion etcher dielectric etching product line sold under the trademark 2300® Flex®. The RF power in them may be intermittent to control the plasma properties and thereby further improve the etching performance (selectivity and damage).

[0069] Alternatively, the plasma-treated reactants may be generated outside the reaction chamber. MKS Instruments' ASTRONi® reactive gas generator can be used to process the reactants before they pass into the reaction chamber. When operated at 2.45 GHz, 7 kW plasma power and a pressure in the range of about 0.5 Torr to about 10 Torr, the reactant O2 can be decomposed into two O· radicals. Preferably, the remote plasma can be generated at a power in the range of about 1 kW to about 10 kW, more preferably about 2.5 kW to about 7.5 kW.

[0070] 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 will have multiple films or layers on it from a previous manufacturing step, including silicon-containing films or layers. The layers may or may not be patterned. Examples of suitable layers, but 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 eExamples include etching stop layer materials such as (wherein a>0 and b, c, d, e≧0) or combinations thereof. In one example, the mask layer may consist of two or more layers, such as a carbon-containing layer and / or a silicon-containing layer and / or a metal-containing layer. In one example, the mask may be SiN and TiN, and the landing layer may be Cu, W, or Ru. The silicon oxide layer may form a dielectric material such as an organic-based or silicon oxide-based low dielectric material (e.g., a porous SiCOH film). Exemplary low dielectric materials are sold by Applied Materials under the trademark names Black Diamond 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.

[0071] The following is a model embodiment of a substrate to which the disclosed etching compound containing oxygen and iodine may be applied for etching.

[0072] In one embodiment, as shown in Figure 1a, the substrate 100 may include a stack of multiple layers. Figure 1a is a cross-sectional view of exemplary layers in a 3D NAND stack for creating a 3D NAND gate. In Figure 1a, a stack of seven alternating SiO / SiN (i.e., 104a / 104b) layers 104 is located on a silicon wafer 102 (i.e., ONON or terabit cell array transistor (TCAT) technology). In some applications, wafer 102 may be a tungsten metal worldline of a 3D NAND structure and / or an embedded landing layer or material such as 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 or diffusion barrier layer such as a metal, metal oxide, or nitride layer (such as AlO, WO, HfO, TiO, TaO, InO, WO, CrO, RuO, CoO, MoO, TiN, TaN, HfN, AlN, WN, MoN, NiN, NbN, CrN, RuN, CoN or a combination thereof). A person skilled in the art will recognize that the barrier layer, such as Ti / TiN, Ti / TiN / Ti, TiZrN, Ta / TaN, TaN / Cu / TaN, TaN / Ru / TaN, etc., may also be composed of the aforementioned combinations of metals, metal oxides, and nitrides. The barrier may also include silicides (TiSiN, TaSiN, TiSi2, MnSiO, etc.), phosphides (CuWP, NiMoP, NiP, etc.), carbides (TaC, TaCN, WCN, etc.), borides (NiMoB, NiB, etc.), or combinations thereof. Those skilled in the art will recognize that the SiN layer 104b can be replaced by a p-Si layer by some technique (e.g., SiO / p-Si or pipe-shaped bit cost scalable (p-BICS) technique). The hard mask layer 106 is located on top of the seven SiO / SiN layers 104. The hard mask layer 106 may be an amorphous carbon (aC) hard mask layer with or without dopant.The hard mask layer 106 may be 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 106 may contain not only C and H but also other elements such as boron, nitrogen, sulfur, chlorine, fluorine, or metals (Al, Zr, Ti, W, Y) to enhance etching resistance during SiO / SiN layer etching. In this case, the hard mask layer 106 is a doped aC layer, such as a boron-doped aC layer or a tungsten-doped aC layer. The anti-reflective coating layer 108 is located above the hard mask layer 106. The patterned photoresist layer 110 is located above the anti-reflective coating layer 108 having a pattern 112. In this specification, an (not shown) SiN layer may be present between the anti-reflective coating layer 108 and the hard mask layer 106 to transfer the pattern 112 in the photoresist layer 110 to the hard mask layer 106 to form a (not shown) patterned hard mask layer. Those skilled in the art will recognize that the stack of layers in the substrate 100 in Figure 1a is provided for exemplary purposes only, and that the disclosed oxygen-iodine-containing etching compounds may be used to etch other types of stacks of layers. Furthermore, those skilled in the art will recognize that the number of alternating SiO / SiN or SiO / p-Si layers 104 in the stack of the substrate 100 may vary (i.e., it may include more than seven or fewer than seven SiO / SiN(104a / 104b) layers as described).

[0073] Figure 1b is a cross-sectional view of an exemplary layer in the 3D NAND stack of Figure 1a, showing polymer deposited on the sidewall of a structure or via 112a formed by etching. The disclosed oxygen- and iodine-containing etching compound may produce fragments during the plasma process, which is suitable for anisotropic etching of the silicon-containing film 104 and for the deposition of the oxygen- and iodine-containing polymer passivation layer 214 on the sidewall of the structure or via 112a to be etched as shown in Figure 1b. The difference between Figure 1b and Figure 1a is that in Figure 1b, the structure or via 112a is formed in the substrate 100 by plasma etching using the disclosed oxygen- and iodine-containing etching compound, thereby depositing the polymer passivation layer 214 on the sidewall of the structure or via 112a. The polymer passivation layer 214 also provides a smoother sidewall, less distortion, and less deformation at the bottom of the structure or via 212. However, the polymer passivation layer 214 can be easily removed or cleaned by dry or wet etching chemicals known in this art.

[0074] Figure 1c is a cross-sectional view of an exemplary layer in the 3D NAND stack of Figure 1a, showing particles 316 generated during alternating SiO / SiN layer etching in the 3D NAND stack. As shown in Figure 1c, particles 316 generated on the sidewall of the alternating SiO / SiN (i.e., 104a / 104b) layer 104 can be minimized by using the disclosed oxygen and iodine-containing etching compound. The difference between Figure 1c and Figure 1b is that in Figure 1c, the alternating SiO / SiN exposed sidewall has particles 316 generated during plasma etching. The applicants do not believe that the disclosed oxygen and iodine-containing etching compound generates the particles 316 shown in Figure 1c.

[0075] Figure 1d is a cross-sectional view of an exemplary layer in the 3D NAND stack of Figure 1a, showing selective isotropic etching of SiN layer 104b exposed on the sidewalls of the 3D NAND stack after an anisotropic etching process. The SiN exposed sidewalls in stack 100 can be selectively etched as shown in Figure 1d by using an etching compound containing the disclosed oxygen and iodine to selectively break the Si-N bonds in SiN layer 104b rather than the Si-O bonds in SiO layer 104a, and to form selective sidewall SiN etching 418 on the stack in SiO / SiN layer 104 in via 112a. The difference between Figure 1d and Figure 1b is that in Figure 1d, the SiN layer exposed on the alternating SiO / SiN sidewalls is selectively etched by the etching compound containing the disclosed oxygen and iodine to form selective sidewall SiN etching 418. Typically, selective sidewall SiN etching 418 is performed by wet etching using a mixture with phosphoric acid. Since wet etching requires moving the substrate to different wet etching equipment, it is known that replacing the wet etching process with a dry plasma etching process can greatly improve the economic aspects of the semiconductor device fabrication process. With respect to the disclosed method, all etching, including the selective sidewall SiN etching shown in Figure 1d, can be performed in an integrated etching apparatus, which can reduce the cost of semiconductor fabrication.

[0076] In another embodiment, as shown in Figure 2, the substrate 200 may include a stack of multiple layers, which is a cross-sectional view of exemplary layers in a DRAM stack for creating a DRAM memory. As shown, a four-layer stack is located on a silicon wafer 202. A hard mask layer 206 is located above a large SiO layer 204. An anti-reflective coating layer 208 is located above the hard mask layer 206. A pattern photoresist layer 210 is located above the anti-reflective coating 208. A (not shown) SiON layer may be present between the anti-reflective coating layer 208 and the hard mask layer 206 to transfer the pattern 212 in the photoresist layer 210 to the hard mask layer 206. Those skilled in the art will recognize that the stack of layers in Figure 2 is provided for exemplary purposes only, and that the disclosed oxygen and iodine-containing etching compounds may be used to etch other stacks of layers, for example, a stack in which the hard mask layer 206 is replaced by a TiN layer. Furthermore, a person skilled in the art will recognize that the number of layers in the stack may vary (i.e., it may include more or fewer layers than those described).

[0077] Figure 3a is an exemplary side cross-sectional view of layers showing a photoresist pattern on an SiO insulating layer surrounding a typical transistor device region for fabricating a transistor structure. As shown, the substrate 300 may include a four-layer stack surrounding a transistor gate electrode region supported on a silicon wafer 302. The illustrated transistor region includes two doped silicon regions 306 that function as source and drain. The transistor gate dielectric 314 is located beneath the gate electrode 316. The entire transistor, i.e., the transistor gate dielectric 314 and gate electrode 316, is surrounded by a thin SiN layer 308, which can then function as an etching stop layer during contact etching. Each transistor device region 306 / 316 is isolated by an SiO isolation region 304 within the silicon wafer 302 to minimize electrical interference. Those skilled in the art will recognize that layer 302 may be located on top of a silicon oxide layer of a silicon-on-insulator (SOI) wafer (not shown). Another SiO layer 310 is deposited on the transistor as an insulating layer and is used to insulate any metal contacts to the transistor device region 306. A patterned photoresist mask 312 is used to pattern the SiO layer 310. Etching is performed in a plasma environment using an etching compound containing the disclosed oxygen and iodine. The patterned photoresist mask 312 acts as a template for etching the SiO layer 310, and the etching is stopped on the SiN layer 308, as shown in Figure 3b.

[0078] Figure 3b is a cross-sectional view of the exemplary layer of Figure 3a after etching of the SiO layer 310. The difference between Figure 3b and Figure 3a is that in Figure 3b, structures or vias 318 are formed in the SiO layer 310 by etching with the disclosed oxygen and iodine-containing etching compound. The SiO layer 310 can be etched using a photoresist layer 312 as a mask layer. The mask layer can be any suitable photoresist mask material such as TiN or aC. Etching can be stopped at the underlying SiN layer 308.

[0079] The disclosed oxygen-iodine-containing etching compounds may be used to etch the SiN layer 308 using different plasma conditions and different mixtures of the etching compounds. Those skilled in the art will recognize that the layer stacks and geometric structures in Figures 3a and 3b are provided for exemplary purposes only, and that the disclosed oxygen-iodine-containing etching compounds may be used to etch other types of layer stacks. Furthermore, those skilled in the art will recognize that the number of layers in the stack may vary (i.e., it may contain more or fewer layers than the four layers described).

[0080] The vapor of the disclosed etching compound containing oxygen and iodine is introduced into a reaction chamber containing a substrate and a silicon-containing film. The vapor can be introduced into the chamber at a flow rate in the range of about 0.1 sccm to about 1 slm, where sccm is standard cubic centimeters per minute and slm is standard liters per minute. For example, with respect to a wafer diameter of 200 mm, the vapor can be introduced into the chamber at a flow rate in the range of about 5 sccm to about 50 sccm. Alternatively, with respect to a wafer diameter of 450 mm, the vapor can be introduced into the chamber at a flow rate in the range of about 25 sccm to about 250 sccm. Those skilled in the art will recognize that the flow rate may vary depending on the tool.

[0081] The disclosed oxygen-iodine-containing etching compounds may be supplied either in their original form or in a blend with an inert gas or solvent such as N2, Ar, Kr, Ne, He, or Xe. The disclosed oxygen-iodine-containing etching compounds may be present in a blend at various concentrations. With respect to liquid oxygen-iodine-containing etching compounds, the vapor form of the oxygen-iodine-containing etching compound may be produced by evaporating the original or blended oxygen-iodine-containing etching compound solution by a conventional evaporation step such as direct distillation, or by bubbling. The original or blended oxygen-iodine-containing etching compound may be supplied in liquid form to an evaporator to evaporate it before introducing it into the reactor.

[0082] Alternatively, the etching compound containing oxygen and iodine, either in its pure or blended form, may be evaporated by passing a carrier gas through a container containing the disclosed oxygen and iodine etching compound, or by bubbling the carrier gas through the disclosed oxygen and iodine etching compound. The carrier gas may include, but is not limited to, Ar, He, N2, and mixtures thereof. Bubbling with the carrier gas may remove any dissolved oxygen present in the pure or blended iodine-containing etching compound solution. The carrier gas and the disclosed oxygen and iodine etching compound are then introduced into the reactor as vapors.

[0083] If necessary, the container containing the disclosed oxygen-iodine etching compound may be heated to a temperature that allows the oxygen-iodine etching compound to become a liquid phase and have sufficient vapor pressure for delivery to the etching tool. The container may be maintained at a temperature in the range of, for example, about 0°C to about 150°C, preferably about 25°C to about 100°C, and more preferably about 25°C to about 50°C. More preferably, the container is maintained at room temperature (about 25°C) to avoid heating the line to the etching tool. Those skilled in the art will recognize that the temperature of the container can be adjusted in a well-known manner to control the amount of oxygen-iodine compound to be evaporated.

[0084] Furthermore, the disclosed etching compounds containing oxygen and iodine can be delivered with a purity ranging from 95% to 99.999% by volume and can be purified by well-known standard purification techniques for the removal of CO, CO2, N2, H2O, HF, H2S, SO2, halides, and other hydrocarbons or hydrohalocarbons.

[0085] 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、 Or a combination thereof. The etching gas and inert gas may be mixed before introduction into the chamber such 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.

[0086] The vapor and inert gas of the disclosed etching compound containing oxygen and iodine are activated by plasma to generate an activated etching gas. The plasma decomposes the etching compound containing oxygen and iodine into a 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.

[0087] 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.

[0088] The vapor of the disclosed etching compound containing oxygen and iodine may be mixed with other gases either before or during its 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.

[0089] Alternatively, the vapor of a compound containing oxygen and iodine may be introduced into the chamber independently of other gases, for example, when it is easier to deliver two or more gases independently or for them to react with each other.

[0090] In another alternative, the etching gas, i.e., the vapor of an etching compound containing oxygen and iodine, and the inert gas are the only two gases used during the etching process.

[0091] Other exemplary gases 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 containing oxygen and iodine and the oxidizing agents may be mixed together before being introduced into the reaction chamber.

[0092] 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).

[0093] Other exemplary gases from which the disclosed etching compounds containing oxygen and iodine 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), C4F9I, C3HF7, COS, FNO, FC≡N, CS2, SO2, SF6, Trans-1, Examples include 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, etching compounds containing about 1% v / v to about 25% v / v of disclosed oxygen and iodine may be used, with the remainder being C4F6 or cC4F8. As shown in the following examples, the combination of the disclosed oxygen-iodine-containing etching compound with a conventional etching gas can result in an increased etching rate while maintaining higher selectivity between the substrate and the layer etched in association with the disclosed oxygen-iodine-containing etching compound.

[0094] The vapor and etching gas of the disclosed etching compound containing oxygen and iodine may be mixed before being introduced into the reaction chamber. Additional etching gas may constitute about 0.01% v / v to about 99.99% v / v of the mixture introduced into the chamber.

[0095] In one non-restrictive plasma etching process, vapors of disclosed oxygen- and iodine-containing compounds, such as C4F9IO, are introduced into a 200 mm dual CCP plasma etching tool using a controlled gas flow device. The controlled gas flow device may be a mass flow controller or bubbler design with an inert gas flow to deliver the vapor of the desired molecule. For high-boiling point molecules, special low-pressure loss mass flow controllers from Brooks Automation (No. GF120XSD), MKS Instruments, etc., may be used. The pressure in the reaction chamber is set to approximately 30 mTorr. Heating of the gas supply source may not be necessary if the vapor pressure is sufficient. The distance between the two CCP electrodes is maintained at 1.35 cm, and the upper electrode RF power is fixed at 750 W. The bottom electrode RF power is changed to analyze the performance of the molecule. As shown in Figure 1a, the reaction chamber contains a substrate with a silicon-containing film on it. The anti-reflective coating layer 108 is patterned / etched with fluorinated hydrocarbons (e.g., CF4 and CH2F2) and oxygen-containing gases (e.g., O2). The amorphous carbon mask layer 106 is patterned / etched with oxygen-containing gases. The SiO and SiN layers 104 are patterned with an argon plasma and an etching compound containing the disclosed oxygen and iodine (e.g., C4F9IO). Argon is introduced into the chamber independently at a flow rate of 250 sccm. C4F9IO is introduced into the chamber independently at 15 sccm. O2 is introduced into the chamber independently and varies from 0 sccm to 20 sccm to determine the optimal etching conditions. Apertures with an aspect ratio of 10:1, preferably 50:1 or higher, are fabricated and can be used as channel holes or contact holes or step etching, slit etching in 3D NAND and DRAM. Similar examples may be used with respect to other stack layers, as shown in Figures 2 and 3a.

[0096] In another non-restrictive exemplary plasma etching process, C4F9IO is introduced into a 200 mm dual CCP plasma etching tool using a controlled gas flow device. The controlled gas flow device may be a mass flow controller. For high-boiling point molecules, special low-pressure loss mass flow controllers from Brooks Automation (No. GF120XSD), MKS Instruments, etc., may be used. The pressure in the reaction chamber is set to approximately 30 mTorr. Heating of the gas supply source may not be necessary if the vapor pressure is sufficient. The distance between the two CCP electrodes is maintained at 1.35 cm, and the upper electrode RF power is fixed at 750 W. The bottom electrode RF power is changed to analyze the performance of C4F9IO. The reaction chamber contains a substrate 100 having a thick SiO layer 104a on it, as shown in Figure 2. Prior to this process, the anti-reflective coating layer 108 is removed by a fluorinated hydrocarbon (e.g., CF4) and an oxygen-containing gas (e.g., O2), and the aC mask layer 106 is removed by an oxygen-containing gas. Argon is introduced into the chamber independently at a flow rate of 250 sccm. C4F9IO is introduced into the chamber independently at 15 sccm. O2 is introduced into the chamber independently at 0 sccm to 20 sccm to determine the optimal etching conditions. An aperture with an aspect ratio of 10:1 or greater is created, which can be used as a contact hole in the DRAM. Similar examples may be used with respect to other stack layers, as shown in Figures 1a and 3a.

[0097] The silicon-containing film and the activated etching gas containing oxygen and iodine react to form volatile byproducts that are removed from the reaction chamber. The aC mask, anti-reflective coating, and photoresist layer are less reactive to the activated etching gas. Therefore, the activated etching gas selectively reacts with the silicon-containing film to form volatile byproducts.

[0098] The temperature and pressure in the reaction chamber are maintained at conditions suitable for the silicon-containing film to react with the activating etching gas. For example, the pressure in the chamber may be maintained between about 0.1 mTorr and about 1000 mTorr, preferably between about 1 mTorr and about 10 mTorr, more preferably between about 10 mTorr and about 1 mTorr, and more preferably between about 10 mTorr and about 100 mTorr, depending on the etching parameters as needed. Similarly, the substrate temperature in the chamber may be in the range of about -196°C to about 500°C, preferably between about -120°C and about 300°C, more preferably between about -100°C and about 50°C, and more preferably between about -10°C and about 40°C. The chamber wall temperature may be in the range of about -196°C to about 300°C, depending on the process requirements.

[0099] The reaction between the silicon-containing film and the activated etching gas results in the anisotropic removal of the silicon-containing film from the substrate. Nitrogen, oxygen, and / or carbon atoms may also be present in the silicon-containing film. Removal is achieved through physical sputtering of the silicon-containing film from plasma ions (promoted by the plasma) and / or Si, where x is in the range of 1 to 4. x This is due to chemical reactions of plasma species that convert them into volatile species such as [specific species].

[0100] The plasma-activated vapor of the disclosed oxygen- and iodine-containing etching compound preferably exhibits high selectivity for the mask, and etching occurs through alternating layers of SiO and SiN, resulting in a vertical etching profile free from distortion or roughness. This is important for 3D NAND applications. Furthermore, the plasma-activated vapor deposits polymers on the sidewalls, minimizing feature profile deformation. For other applications such as DRAM and 2D NAND, for example, plasma-activated etching gases under different process conditions can selectively etch SiO from SiN. Plasma-activated etching gases can selectively etch SiO and / or SiN from mask layers such as aC, photoresist, p-Si, or silicon carbide; or from metal contact layers such as Cu, W, or Ru; or from channel regions consisting of SiGe or polysilicon regions.

[0101] The disclosed etching process uses an etching compound containing the disclosed oxygen and iodine as the etching gas to create channel holes, gate trenches, stepped contacts, condenser holes, contact holes, contact etch, slit etch, self-aligned contacts, self-aligned vias, super vias, etc., in a silicon-containing film. The resulting apertures may have aspect ratios in the range of about 10:1 to about 200:1 and diameters in the range of about 5 nm to about 500 nm, preferably less than 100 nm. For example, those skilled in the art will recognize that channel hole etching can create apertures in a silicon-containing film having aspect ratios greater than 50:1.

[0102] A typical material to be etched may be SiO. The process of etching SiO may involve etching trenches of thermal oxides such as borosilicate glass (BPSG), tetraethyl orthosilicate (TEOS), or low deposition rate TEOS (LDTEOS), which are produced by wet or dry processes. The etching stop layer may be silicon nitride or silicon oxygen nitride (SiON) or polysilicon. The mask material used may be aC, p-Si, or a photoresist material. The etching compounds containing oxygen and iodine disclosed herein are used to etch SiO, SiN, p-Si, and / or aC substrate films.

[0103] As shown in the following examples, evaluations of dry etching of SiO, SiN, p-Si, and aC films using the disclosed oxygen- and iodine-containing etching compounds demonstrate that oxygen- and iodine-containing HFCs provide the highest selectivity for silicon oxide over amorphous carbon, silicon nitride, and p-Si compared to prior art fluorocarbons. The reason for this high selectivity is thought to be the formation of low F / C iodine-containing fragments during plasma dissociation of the etching gas, which then form a protective polymer film on the substrate. Furthermore, the iodine is ionized, causing heavy iodine ions to collide with the surface, similar to inert gases such as Ar, Kr, and Xe. The ionized iodine atoms also modify the surface of the organic hard mask by doping it to improve its etching resistance, which is advantageous for high aspect ratio etching. The activated etching compounds containing oxygen and iodine generate iodine ions that reinforce the patterned mask layer, thereby reinforcing the patterned mask layer and minimizing damage while forming a patterned structure on the substrate. The etching gas results described herein are not only expected to be beneficial for etching processes of patterned structures, such as contact etching processes, but also potentially beneficial for other etching processes on silicon or metal-containing substrates, including low dielectric constant etching processes. In addition, in processes for forming patterned structures by etching with the disclosed oxygen-iodine-containing etching compounds, the etching resistance of the patterned mask layer can be enhanced by modifying the surface by doping the surface of the patterned mask layer with iodine. In this case, iodide ions from the activated oxygen-iodine-containing etching compound are injected into the patterned mask layer (i.e., the surface and / or body / bulk of the patterned mask layer) while etching the silicon-containing film from the substrate to form the patterned structure. Furthermore, the disclosed oxygen-iodine-containing etching compounds are suitable for reducing the global warming potential caused by perfluorocarbon compounds.

[0104] By adjusting process parameters, the iodine doping concentration can be increased from 0.1% to 99.9% across the entire deposited film, depending on the application.

[0105] The iodine atom concentration in the substrate material ranges from approximately 0.1% to approximately 99.9%, and is uniform throughout the entire deposited film.

[0106] The iodine atom concentration in the substrate material ranges from approximately 1% to approximately 50%, and is uniform throughout the entire deposited film.

[0107] The iodine atom concentration in the substrate material ranges from approximately 2% to 30%, and is uniform throughout the entire deposited film.

[0108] Furthermore, oxygen in an activated etching compound containing oxygen and iodine can be doped into the aC mask layer. The oxygen in the activated etching compound containing oxygen and iodine can reduce or eliminate the use of oxidizing agents. In some embodiments, no oxidizing agent may be introduced. In some embodiments, little to no oxidizing agent may be used. As described above, oxidizing agents remove deposited polymers but can deform the etched structure. Using the disclosed oxygen and iodine-containing etching compounds, little to no oxidizing agent can be applied, and as a result, the etched structure maintains a linear profile. Furthermore, the oxygen in the activated etching compound containing oxygen and iodine helps to incorporate more iodine-containing ions, radicals, and species into the mask layer, such as the carbon-containing layer. In addition, the oxygen in the activated etching compound containing oxygen and iodine also helps to increase the etching rate of the silicon-containing layer. [Examples]

[0109] 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.

[0110] In the following examples, experiments were conducted using a commercially available LAM tool 4520XLe200mm (CCP dual-frequency plasma) or a commercially available AMEC300mmPrimo SSC HD-RIE etcher. The flat wafers were purchased from Advantive Tech. The flat wafers tested were the following four different substrates.

[0111] The experiment was conducted at the Air Liquide R&D Innovation Campus Delaware using a commercially available LAM tool 4520XLe200mm (CCP dual-frequency plasma, 10 gas lines). The flat wafers were purchased from Advantive Tech. The flat wafers tested are as follows: • 2 μm PECVD TEOS on a Si substrate; • 2µm PECVD Si3N4 on a Si substrate; • 300nm LP-CVD poly-Si on a Si substrate; and • 350nm PE-CVD aC on a Si substrate.

[0112] In planar tests, etching rate and selectivity were evaluated by ellipsometry and SEM at different O2 flow rates by measuring the change in etching thickness as a function of etching time. The gas flow rate for process test molecules was kept constant at 15 sccm, and the Ar flow rate at 250 sccm, while the O2 flow rate was screened at 0–20 sccm. Subsequently, the polymer composition was determined by X-ray photoelectron spectroscopy.

[0113] The etching experiment involved four 1.5 × 1.5 cm samples with four different substrate materials, including SiO2, Si3N4, p-Si, and aC. 2This was performed on a planar coupon. The coupon is placed on a carrier wafer with a diameter of 200 mm and held in contact using silicone oil or thermal paste. Alternatively, double-sided carbon tape obtained from SPI supplies may be used to attach the coupon to the carrier wafer.

[0114] Etching tests were performed at a pressure of 30 mTorr, a power supply of 750 W (27 MHz), a bias power of 1500 W (2 MHz), and a temperature of 20°C. The feed mixture contained 250 sccm of Ar and 15 sccm of etching gas, while the O2 content varied from 0 to 20 sccm.

[0115] 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).

[0116] Example 1: Plasma-enhanced dry etching using C3F7IO [ka] C3F7IO, 2-iodo-1,1,2,2-tetrafluoro-1-(trifluoromethoxy)ethane, was applied to plasma etching of silicon oxide (SiO2).

[0117] [Table 3]

[0118] Figure 4 shows the etching rate (ER) and selectivity of C3F7IO for four different substrates, namely SiO, SiN, p-Si, and aC, at different O2 flow rates (0-20 sccm). The ERs for SiO2 and aC are inversely proportional: as the O2 flow rate decreases, the ER for SiO2 increases and the ER for aC decreases. The highest SiO2 / aC selectivity is shown at O2=0 sccm, with an ER for SiO2 of approximately 17:1 and a min of approximately 535 nm. Table 4 compares C3F7IO to the standard etching gas C4F6, a benchmark commonly used in the industry. C3F7IO exhibits approximately 70% higher SiO2 / aC selectivity than the benchmark gas (C4F6) at similar etching rates. Of note are the carbon number of the two molecules (C3 vs. C4) and the difference in the F / C ratio of the two etching compounds: C3F7IO has an F / C ratio of 2.33, while C4F6 has an F / C ratio of 1.5. Generally, according to the literature, a higher F / C ratio results in lower selectivity because there are fewer carbon atoms to form polymers and protect the pattern mask. However, C3F7IO exhibits high selectivity even with a low carbon number because it contains iodine and oxygen in the etching compound. Figure 8 is a graph showing the etching rates of SiO, SiN, p-Si, and aC using C4F6.

[0119] [Table 4]

[0120] XPS Data Analysis: Process conditions were adjusted to simulate the formation of polymer layers on the top and sidewalls during the plasma etching process: bare aC and Si coupons were etched at 30 mTorr for 60 seconds with a power supply of 750 W (27 MHz) and no bias power on the substrate (0 W, 2 MHz). The process was supplied with a mixture containing 125 sccm of Ar and 30 sccm of C3F7IO, but without O2, as shown in Table 5. Due to the absence of bias power, ions reaching the substrate may not have sufficient energy to etch the substrate. Furthermore, neutral and active species reaching the substrate surface adhere to the surface based on their adhesion coefficient, resulting in the deposition of a thin polymer layer on top. This thin polymer layer can contribute to sidewall passivation and often provides selectivity.

[0121] [Table 5]

[0122] For the XPS depth profile, in order to minimize chemical damage and to avoid the possibility of iodine atom knock-on during Ar sputtering, which can occur during sputtering of organic materials such as fluorocarbon polymers and amorphous carbon, monatomic Ar + Instead, Ar1000 is a large cluster ion gas with an ion energy of 5 keV. + The following was used. Figure 5a shows the depth profile on the aC substrate. Figure 5b shows a magnified view of Figure 3a without C1s. Table 6 shows the XPS results of etching a carbon-containing substrate using C3F7IO.

[0123] [Table 6]

[0124] [Table 7]

[0125] Fluorocarbon compounds containing oxygen and iodine exhibit interesting behavior during etching of carbon-containing masks compared to Si-containing materials. XPS data indicates that iodine modifies the carbon surface, penetrating deeply into the aC mask as well as providing a doping effect, helping to protect the hard mask layer during etching. Table 7 shows XPS results of etching a silicon-containing substrate using C3F7IO. On a Si substrate, structure C... x F y I z O k A thin polymer layer containing iodine is observed superficially, but the iodine content decreases to zero after approximately 20 seconds of etching. On the other hand, in the aC layer, iodine can be found deeper and at a lower percentage (<2%). In addition, oxygen derived from C3F7IO is incorporated into the bulk of the aC mask layer at a rate of 2-3%. By adjusting process parameters, the iodine doping concentration can be increased from 0.1 to 99.9% across the entire deposited film, depending on the application.

[0126] Comparing the F1s peak and I3d peak in the XPS shown in Table 5, the depth profile on the aC substrate (in Figure 7, the y-axis represents counts per second and the x-axis represents the binding energy (eV)) is: • Fluorine deposits on the surface to form a thin IFC (iodofluorocarbon) polymer (F1s is a maximum of 120 seconds of Ar etching). • Iodine penetrates deeper into the aC mask (I3d requires etching for up to 500 seconds). This indicates.

[0127] Thus, iodine and oxygen species help protect the aC mask during etching by modifying the surface and doping the aC layer with iodine. Iodine also helps minimize damage by strengthening the aC mask. In addition, oxygen-containing species help improve the etching resistance of the pattern mask by retaining and incorporating iodine in a higher proportion within the pattern mask.

[0128] To demonstrate reproducibility, each etching test was repeated three times. The standard deviation of the mean of the three measurements is shown as error bars in Figure 4. The subject matter described herein may be described in relation to exemplary implementations for handling one or more computing application functions / operations for computing applications having user-interactive components, but the subject matter is not limited to these particular embodiments. Rather, the techniques described herein can be applied to any suitable type of user-interactive component execution management method, system, platform, and / or apparatus.

[0129] 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.

[0130] 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 patterned structure, a) A reaction chamber containing a substrate having a silicon-containing film deposited on the substrate and a patterned mask layer deposited on the silicon-containing film contains C3F7IO and its isomers, and formula C ｎ H ｘ F ｙ I ｚ O ｅ The step of introducing a vapor of an etching compound containing oxygen and iodine, selected from the group consisting of compounds having (wherein 4 ≤ n ≤ 10, 0 ≤ x ≤ 21, 0 ≤ y ≤ 21, 1 ≤ z ≤ 4, and 1 ≤ e ≤ 2); b) The step of activating the plasma to produce an activated etching compound containing oxygen and iodine; and c) Proceeding an etching reaction between the activated etching compound containing oxygen and iodine and the silicon-containing film to selectively etch the silicon-containing film from the patterned mask layer, thereby forming the patterned structure; A method that includes this.

2. The method according to claim 1, wherein step c) includes modifying the patterned mask layer or doping the patterned mask layer with iodine derived from iodide ions generated from an activated etching compound containing oxygen and iodine.

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. 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, further optionally comprising the step of introducing an oxidizing agent selected from O, O, CO, CO, NO, N, O, NO, H, O, H, O, COS, SO and combinations thereof into the reaction chamber.

5. The silicon-containing film is silicon oxide (SiO), silicon nitride (SiN), crystalline Si, polysilicon (p-Si), polycrystalline silicon, amorphous silicon, low dielectric constant SiCOH, SiOCN, SiC, SiON, Si ａ O ｂ H ｃ C ｄ The method according to claim 1, comprising Ne (wherein a > 0; b, c, d, and e ≥ 0), alternating layers of SiO and SiN(ONON), or alternating layers of SiO and p-Si(OPOP).

6. The method according to claim 5, wherein the etching compound containing oxygen and iodine plasma-etches alternating layers of SiO and SiN (ONON) with a selectivity of about 1:2 to about 2:1 with respect to the SiO layer versus the SiN layer.

7. The method according to claim 5, wherein the etching compound containing oxygen and iodine plasma-etches alternating layers of SiO and p-Si (OPOP) with a selectivity of about 1:2 to about 2:1 with respect to the SiO layer and the p-Si layer.

8. The method according to any one of claims 1 to 5, wherein the patterned mask layer is a carbon-containing layer, an amorphous carbon layer, a doped amorphous carbon layer, a photoresist layer, an anti-reflective layer, an organic planarization layer, or a combination thereof.

9. The further step includes introducing an additional etching gas into the reaction chamber, wherein the additional etching gas is cC ４ F ８ , C ４ F ８ , cC ５ 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 ４ F ９ 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 ) or a combination thereof, the method according to any one of claims 1 to 5.

10. The method according to any one of claims 1 to 5, wherein the patterned structure formed on the silicon-containing film has an aspect ratio of about 1:1 to about 200:

1.

11. A method for forming a patterned structure, a) In a reaction chamber containing a substrate having a silicon-containing film deposited on the substrate and a patterned mask layer deposited on the silicon-containing film, C ３ F ７ Steps to introduce steam into the IO; b) Activating the plasma to generate activated C ３ F ７ IO; and c) The activated C ３ F ７ A step of carrying out an etching reaction between IO and the silicon-containing film to selectively etch the silicon-containing film from the patterned mask layer, thereby forming the patterned structure; A method that includes this.

12. The aforementioned step c) The activated C ３ F ７ Iodine derived from iodide ions generated from IO, the pattern The method according to claim 11, comprising the step of modifying the patterned mask layer by doping the patterned mask layer.

13. A method for modifying the surface of a patterned mask layer formed on a substrate by doping the surface of the patterned mask layer with iodine, In a reaction chamber containing a substrate having a silicon-containing film deposited on the substrate and a patterned mask layer deposited on the silicon-containing film, formula C ｎ H ｘ F ｙ I ｚ O ｅ Introducing a vapor of an etching compound containing oxygen and iodine (wherein 4 ≤ n ≤ 10, 0 ≤ x ≤ 21, 0 ≤ y ≤ 21, 1 ≤ z ≤ 4, and 1 ≤ e ≤ 2); Etching the silicon-containing film from the patterned mask layer using an activated etching compound containing oxygen and iodine, formed by activating a plasma, to form a patterned structure; Including; A method comprising doping the patterned mask layer with iodide ions generated from an activated etching compound containing oxygen and iodine while forming the patterned structure on the substrate, thereby strengthening the patterned mask layer and minimizing damage to the patterned mask layer.

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