Iodine-containing fluorocarbon and hydrofluorocarbon compounds for etching semiconductor structures

Abstract

Disclosed are methods for etching silicon-containing films to form patterned structures, methods for reinforcing and / or strengthening and / or minimizing damage to a patterned mask layer while forming the patterned structure, and methods for increasing the etch resistance of a patterned mask layer in the process of forming the patterned structure. The methods include using a compound of formula C as an etching gas. n H x F y I z where 4≦n≦10, 0≦x≦21, 0≦y≦21, and 1≦z≦4. The activated iodine-containing etch compound generates iodine ions that are implanted into the patterned hard mask layer, thereby strengthening the patterned mask layer.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Patent Application No. 16 / 913,696, filed June 26, 2020, which is incorporated by reference herein in its entirety for all purposes.

[0002] Disclosed are methods for etching silicon-containing films to form patterned structures, methods for reinforcing and / or strengthening and / or minimizing damage to a patterned mask layer while forming a patterned structure, and methods for increasing the etch resistance of a patterned mask layer in the process of forming a patterned structure using an iodine-containing etching compound. The iodine-containing etching compound is represented by the formula C n H x F y I z wherein 4≦n≦10, 0≦x≦21, 0≦y≦21, and 1≦z≦4. [Background technology]

[0003] In the semiconductor industry, etching of stacks of multiple SiO / SiN or SiO / polysilicon (p-Si) layers is important for 3D NAND. 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 layer to be etched is essential. Furthermore, the etched structure should have a straight vertical profile without distortion and low line etch roughness (LER).

[0004] Conventional etching gases include octafluorocyclobutane (cCF), hexafluoro-1,3-butadiene (CF), CF, CHF, CHF, and / or CHF. It is well known that increasing the C:F ratio (i.e., CF > CF > CF) increases selectivity and polymer deposition rate. See, for example, U.S. Patent No. 6,387,287 to Hung et al. In addition, other gases, such as inert gases like Ar, Kr, or Xe, are added to the plasma, where they are ionized and accelerated toward the wafer surface, bombarding the surface and assisting in the etching process. Because they are inert gases, they do not directly participate in the chemical reactions of the etching process.

[0005] However, conventional etch chemistries may be unable to provide features such as holes or trenches with aspect ratios higher than 20:1 required for emerging applications (e.g., 3D NAND) at least due to insufficient etch-resistant polymer deposition on the sidewalls during the plasma etching process. x F y -polymers, where x is in the range of 0.01 to 1 and y is in the range of 0.01 to 4, can be susceptible to etching. As a result, the etched patterns may not be vertical, and the etched structures may exhibit distortion, dimensional changes, pattern collapse, and / or increased roughness.

[0006] The distortion can be due to sidewall etching of the mask layer, which can often be an amorphous carbon (aC) material, which can cause an increase in the opening of the mask and can be etched by oxygen radicals in the plasma, resulting in a distorted or angled / curved etched structure.

[0007] Iodine-containing compounds have been used as etching gases and / or to reduce global warming potential (GWP). For example, Gupta et al. (U.S. Pat. No. 10,607,850) describe a compound of formula C a H x F y Iz (wherein a=1-3, x=0-6, y=1-7, z=1-2, and when a=1, x+y+z=4, when a=2, x+y+z=4 or 6, and when a=3, x+y+z=6 or 8). Chung (U.S. Pat. No. 9,460,935) discloses, inter alia, etching first and second etching layers under plasma generated using 1,1,2,2-tetrafluoro-1-iodo-ethane. See also Karecki et al., "Plasma etching of dielectric films with novel iodofluorocarbon chemistries: iodotrifluoroethylene and 1-iodoheptafluoropropane," J. Vac. Sci. Technol. A 16,755 (1998); JP 2006 / 108484 A; and TWI 343601. Iodine-containing etching compounds have been shown to significantly reduce global warming emissions compared to perfluorocarbon compounds (see S. Karecki, L. Pruette, and R. Reif, J. Electrochem. Soc. 145, 4305 (1998)).

[0008] It is important to minimize distortion and achieve the high aspect ratios (i.e., up to 200:1) required for the application (e.g., contact etching or 3D NAND). Furthermore, the etch is not limited to selectivity to the photoresist mask. The etch is performed on aC, 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 between other materials such as materials where a>0; b, c, d, and e≧0. Summary of the Invention [Problem to be solved by the invention]

[0009] Therefore, there is a need for suitable etching gas compositions for use in plasma etching applications that maintain selectivity and high aspect ratios over a wide range of process conditions. [Means for solving the problem]

[0010] A method for forming a patterned structure is disclosed, the method comprising: A reaction chamber containing a substrate having a silicon-containing film disposed thereon and a patterned mask layer disposed on the silicon-containing layer is provided with a compound of formula C n H x F y I z introducing vapor of an iodine-containing etching compound having the formula: where 4≦n≦10, 0≦x≦21, 0≦y≦21, and 1≦z≦4; activating the plasma to produce an activated iodine-containing etching compound; and allowing an etching reaction to proceed between the activated iodine-containing etching compound and the silicon-containing film to selectively etch the silicon-containing film from the patterned mask layer, thereby forming a patterned structure; The disclosed method may include one or more of the following aspects: further comprising introducing an oxidant 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; · further comprising 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; · The inert gas is Xe; ·The inert gas is Kr; · The iodine-containing etching compound is a hydrofluorocarbon compound; · The iodine-containing etching compound is an organic fluorine compound; · The iodine-containing etching compound is a fluorine-containing hydrocarbon compound; · The iodine-containing etching compound is a fluorocarbon compound; The iodine-containing etching compound is a hydrocarbon compound; ·Iodine-containing etching compounds do not contain hydrogen; ·Iodine-containing etching compounds contain hydrogen; · Iodine-containing etching compounds contain fluorine; · Iodine-containing etching compounds do not contain fluorine; Iodine-containing etching compounds are C4F9I and C5F 11 I, C6F 13 I, C7F 15 I, C8F 17 I, C9F 19 I C 10 F 21 I, or an isomer thereof; Iodine-containing etching compounds include C4HF8I and C5HF 10 I, C6HF 12 I, C7HF 14 I, C8HF 16 I, C9HF 18 I C 10 HF 20 I, C4HF6I, C5HF8I, C6HF 10 I, C7HF 12 I, C8HF 14 I, C9HF 16 I C 10 HF 18 I, C4HF4I, C5HF6I, C6HF8I, C7HF 10 I, C8HF 12 I, C9HF 14 I C 10 HF 16 I, C4HF7I2, C5HF9I2, C6HF 11 I2, C7HF 13 I2, C8HF 15 I2, C9HF 17 I2, C 10 HF 19I2, C4HF5I2, C5HF7I2, C6HF9I2, C7HF 11 I2, C8HF 13 I2, C9HF 15 I2, C 10 HF 17 I2, C4HF3I2, C5HF5I2, C6HF7I2, C7HF9I2, C8HF 11 I2, C9HF 13 I2, C 10 HF 15 I2, C4HF6I3, C5HF8I3, C6HF 10 I3, C7HF 12 I3, C8HF 14 I3, C9HF 16 I3, C 10 HF 18 I3, C4HF4I3, C5HF6I3, C6HF8I3, C7HF 10 I3, C8HF 12 I3, C9HF 14 I3, C 10 HF 16 I3, C4HF5I4, C5HF7I4, C6HF9I4, C7HF 11 I4, C8HF 13 I4, C9HF 15 I4, C 10 HF 17 I4, C4HF3I4, C5HF5I4, C6HF7I4, C7HF9I4, C8HF 11 I4, C9HF 13 I4, C 10 HF 15 I4, C4HFI4, C5HF3I4, C6HF5I4, C7HF7I4, C8HF9I4, C9HF<​​​​​​​​​​​​​​​​​​​​​13 I, C9H2F 15 I C 10 H2F 17 I, C4H2F6I2, C5H2F8I2, C6H2F 10 I2, C7H2F 12 I2, C8H2F 14 I2, C9H2F 16 I2, C 10 H2F 18 I2, C4H2F4I2, C5H2F6I2, C6H2F8I2, C7H2F 10 I2, C8H2F 12 I2, C9H2F 14 I2, C 10 H2F 16 I2, C4H2F5I3, C5H2F7I3, C6H2F9I3, C7H2F 11 I3, C8H2F 13 I3, C9H2F 15 I3, C 10 H2F 17 I3, C4H2F3I3, C5H2F5I3, C6H2F7I3, C7H2F9I3, C8H2F 11 I3, C9H2F 13 I3, C 10 H2F 15 I3, C4H2F4I4, C5H2F6I4, C6H2F8I4, C7H2F 10 I4, C8H2F 12 I4, C9H2F 14 I4, C 10 H2F 16 I4, C4H2F2I4, C5H2F4I4, C6H2F6I4, C7H2F8I4, C8H2F 10 I4, C9H2F 12 I4, C 10 H2F 14 I4, or its isomers; Iodine-containing etching compounds include C4H3F6I, C5H3F8I, and C6H3F 10 I, C7H3F 12 I, C8H3F 14 I, C9H3F 16 I C 10 H3F 18 I, C4H3F4I, C5H3F6I, C6H3F8I, C7H3F 10I, C8H3F 12 I, C9H3F 14 I, C 10 H3F 16 I, C4H3F5I2, C5H3F7I2, C6H3F9I2, C7H3F 11 I2, C8H3F 13 I2, C9H3F 15 I2, C 10 H3F 17 I2, C4H3F3I2, C5H3F5I2, C6H3F7I2, C7H3F9I2, C8H3F 11 I2, C9H3F 13 I2, C 10 H3F 15 I2, C4H3F4I3, C5H3F6I3, C6H3F8I3, C7H3F 10 I3, C8H3F 12 I3, C9H3F 14 I3, C 10 H3F<00​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​15 I, C4H4F4I2, C5H4F6I2, C6H4F8I2, C7H4F 10 I2, C8H4F 12 I2, C9H4F 14 I2, C 10 H4F 16 I2, C4H4F2I2, C5H4F4I2, C6H4F6I2, C7H4F8I2, C8H4F 10 I2, C9H4F 12 I2, C 10 H4F 14 I2, C4H4F3I3, C5H4F5I3, C6H4F7I3, C7H4F9I3, C8H4F 11 I3, C9H4F 13 I3, C 10 H4F 15 I3, C4H4FI3, C5H4F3I3, C6H4F5I3, C7H4F7I3, C8H4F9I3, C9H4F 11 I3, C 10 H4F 13 I3, C4H4F2I4, C5H4F4I4, C6H4F6I4, C7H4F8I4, C8H4F 10 I4, C9H4F 12 I4, C 10 H4F 14 I4, C4H4I4, C5H4F2I4, C6H4F4I4, C7H4F6I4, C8H4F8I4, C9H4F 10 I4, C 10 H4F 12 I4, or its isomers; The iodine-containing etching compound is C4F9I or its isomers; · Plasma-activated iodine-containing etching compounds react with silicon-containing films to form volatile by-products; ·Volatile by-products are removed from the reaction chamber; · the silicon-containing film comprises oxygen, nitrogen, carbon, hydrogen, carbon, or a combination 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 Ob H c C d N e (wherein a>0; b, c, d, and e≧0), including alternating layers of SiO and SiN(ONON), alternating layers of SiO and p-Si(OPOP); the silicon-containing film optionally comprises dopants such as B, C, P, As, Ga, In, Sn, Sb, Bi and / or Ge, or combinations thereof; · the silicon-containing film comprises oxygen, nitrogen, carbon, hydrogen, or a combination thereof; The silicon-containing film is SiO x N y H z C k wherein x ranges from 0 to 2, y ranges from 0 to 4, z ranges from 0 to about 1, and k ranges from 0 to 1; The silicon-containing film comprises a SiO layer; The silicon-containing film is a SiN layer; The silicon-containing film comprises alternating layers of SiO and SiN(ONON); The silicon-containing film comprises alternating layers of SiO and p-Si (OPOP); The silicon-containing film comprises dopants such as B, C, P, As, Ga, In, Sn, Sb, Bi and / or Ge; · Alternating layers of silicon oxide, silicon nitride, polysilicon, crystalline silicon, SiOCH, SiON, Si a O b C c N d H e (a>0; b, c, d and e≧0) or a combination thereof; · the alternating layers contain oxygen atoms, nitrogen atoms, carbon atoms, hydrogen atoms or combinations thereof; · The alternating layers are silicon-containing films; the alternating layers include layers of silicon oxide and layers of silicon nitride; · the alternating layers include alternating layers of silicon oxide and silicon nitride; · the alternating layers are alternating layers of silicon oxide and silicon nitride; · the alternating layers include layers of silicon oxide and layers of polysilicon; · the alternating layers include alternating layers of silicon oxide and polysilicon; · the alternating layers are alternating layers of silicon oxide and polysilicon; A hard mask layer is disposed over the silicon-containing layer; The hard mask layer is a patterned hard mask layer; The hard mask layer is an amorphous carbon layer, a doped amorphous carbon layer, a photoresist layer, an anti-reflective layer, an organic planarization layer, or a combination thereof; the hard mask layer is a layer of CVD, PECVD, ALD, PEALD or spin-on deposited (SOD) amorphous carbon or doped amorphous carbon, silicon-containing spin-on mask, or carbon-containing spin-on mask; The hard mask layer is an amorphous carbon (aC) layer; The hard mask layer is a doped carbon layer; The doped amorphous carbon layer is a boron-doped aC layer; The doped amorphous carbon layer is a tungsten-doped aC layer; · Alternating layers are selectively etched from the hard mask layer; · 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 oxide and polysilicon are selectively etched from the aC layer; · Alternating layers of silicon oxide and polysilicon are selectively etched from the doped carbon layer; · The silicon oxide layer is selectively etched from the hard mask layer; · The silicon oxide layer is selectively etched from the aC layer; · The silicon oxide layer is selectively etched from the doped carbon layer; · The silicon nitride layer is selectively etched from the hard mask layer; · The silicon nitride layer is selectively etched from the aC layer; · The silicon nitride layer is selectively etched from the doped carbon layer; · The polysilicon layer is selectively etched from the hard mask layer; · The polysilicon layer is selectively etched from the aC layer; · The polysilicon layer is selectively etched from the doped carbon layer; The silicon-containing film is selectively etched from an amorphous carbon layer, a doped amorphous carbon layer, a photoresist layer, an antireflective layer, or an organic planarization layer; The silicon oxide layer is selectively etched from the amorphous carbon layer, the doped amorphous carbon layer, the photoresist layer, the anti-reflective layer, or the organic planarization layer; · Iodine-containing etching compounds etch both silicon oxide and silicon nitride layers with high etching rates; · the selectivity of the iodine-containing etching compound to etch both silicon oxide and silicon nitride layers is in the range of about 1:2 to about 2:1; a plasma of an iodine-containing etching compound that etches alternating SiO and SiN(ONON) layers has a selectivity of about 1:2 to about 2:1 for SiO layers to SiN layers; A plasma of an iodine-containing etching compound that etches alternating SiO and SiN(ONON) layers has a selectivity of about 1:1 for SiO layers versus SiN layers; · The selectivity of the iodine-containing etching compound to etch both silicon oxide and silicon nitride layers is about 1:1; · Iodine-containing etching compounds etch both silicon oxide and polysilicon layers with high etching rates; · the selectivity of the iodine-containing etching compound to etch both the silicon oxide layer and the polysilicon layer is in the range of about 1:2 to about 2:1; a plasma of an iodine-containing etching compound that etches alternating layers of SiO and p-Si (OPOP) has a selectivity of about 1:2 to about 2:1 for SiO layers to p-Si layers; A plasma of an iodine-containing etching compound that etches alternating layers of SiO and p-Si (OPOP) has a selectivity of about 1:1 for SiO layers versus p-Si layers; · The selectivity of the iodine-containing etching compound to etch both silicon oxide and polysilicon layers is approximately 1:1; The etch rate of etching a silicon oxide layer using an iodine-containing etching compound is higher than the etch rate of etching a silicon oxide layer using conventional etching gases cC4F8, C4F6, CF4, CH3F, CF3H, CH2F2, or combinations thereof; · The etching rate of the silicon oxide layer using an iodine-containing etching compound is about 640 nm / min; The etching rate of the silicon oxide layer using the iodine-containing etching compound is higher than the etching rate of the silicon oxide layer SiO2 using the conventional etching gas cC4F8; The etching rate of the silicon oxide layer using the iodine-containing etching compound is higher than the etching rate of the silicon oxide layer SiO2 using the conventional etching gas C4F6; The etching rate of the silicon oxide layer using C4F9I is higher than the etching rate of the silicon oxide layer SiO2 using the etching gases cC4F8 or C4F6 while heating the iodine-containing etching compound for plasma etching to avoid condensation; The etching rate of a silicon oxide layer using C4F9I is higher than the etching rate of a silicon oxide layer SiO2 using the etching gas cC4F8 while heating the iodine-containing etching compound for plasma etching to avoid condensation; The etching rate of a silicon oxide layer using C4F9I is higher than the etching rate of a silicon oxide layer SiO2 using the etching gas C4F6 while heating the iodine-containing etching compound for plasma etching to avoid condensation; Heating iodine-containing etching compounds for plasma etching to avoid condensation; the patterned structures formed in the silicon-containing film have an aspect ratio between about 1:1 and about 200:1; Heating an iodine-containing etching compound for plasma etching to maintain a target flow rate of the iodine-containing etching compound; The iodine-containing etching compound selectively etches the silicon-containing film from the landing layer located at the bottom of the silicon-containing film being etched; The landing layer is a buried landing layer located at the bottom of the structure to be etched; The landing layer is an etch stop layer; The landing layer is a silicon layer; The landing layer is a metal layer; The landing layer is a tungsten metal world line of the 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 metal oxide or metal nitride layer; the landing layer is a layer of AlO, WO, TiN, or TaN; the metal layer is selected from W, Cu, Al, Ru, Pt, Ti, Ta, Ni, Co, Mo, or an etch stop layer is selected from AlO, WO, TiN, TaN; the landing layer is a metal oxide or metal nitride layer selected from AlO, WO, HfO, TiO, TaO, InO, WO, CrO, RuO, CoO, MoO, ZrO, SnO, TiN, TaN, HfN, AlN, WN, MoN, NiN, NbN, CrN, RuN, CoN, ZrN, SrN, or a combination thereof; · Adding oxygen-containing gas to iodine-containing etching compounds; The oxygen-containing gas is selected from the group consisting of O2, O3, CO, CO2, NO, NO2, N2O, SO2, COS, H2O, and combinations thereof; · The oxygen-containing gas is O2; · mixing an iodine-containing etching compound with an oxygen-containing gas to form a mixture prior to introduction into the chamber; · Introduce iodine-containing etching compounds separately from oxygen-containing gases; · Sequentially introducing an oxygen-containing gas and an iodine-containing etching compound; The oxygen-containing gas comprises from about 0.01% v / v to about 99.9% v / v of the total volume of the iodine-containing etching compound and the oxygen-containing gas; The oxygen-containing gas comprises about 0.01% v / v to about 10% v / v of the total volume of the iodine-containing etching compound and the oxygen-containing gas; · Mixing an iodine-containing etching compound with an inert gas to form a mixture before introducing it into the chamber; · Iodine-containing etching compounds are introduced separately from the inert gas; · Continuous introduction of inert gas and pulsed introduction of iodine-containing etching compounds; The inert gas comprises from about 0.01% v / v to about 99.9% v / v of the total volume of the iodine-containing etching compound vapor and the inert gas; The inert gas accounts for about 90% v / v to about 99% v / v of the total volume of the iodine-containing etching compound vapor and the inert gas; 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 structures are contact holes; The patterned structure is a 3D NAND contact hole; · The patterned structures are DRAM contacts; The patterned structure is a channel hole; The patterned structure is a 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 supervia; · further comprising introducing an additional etching gas into the iodine-containing etching compound; Additional etching gases include cC4F8, C4F8, cC5F8, C5F8, C4F6, CF4, CH3F, CF3H, CH2F2, C3HF7, C3F6, C3H2F6, C3H2F4, C3H3F5, C4HF7, C5HF9, C3F6, C3F8, CF3I, C2F3I, C2F5I, C3F7I, 1-iodoheptafluoropropane (1-C3F7I), 2-iodoheptafluoropropane (2-C3F7I), C3HF7, COS, FNO, FC≡N, CS2, SO2, SF6, trans-1,1,1,4,4,4-hexafluoro-2-butene ( trans-C4H2F6), cis-1,1,1,4,4,4-hexafluoro-2-butene (cis-C4H2F6), hexafluoroisobutene (C4H2F6), trans-1,1,2,2,3,4-hexafluorocyclobutane (trans-C4H2F6), 1,1,2,2,3-pentafluorocyclobutane (C4H3F5), 1,1,2,2-tetrafluorocyclobutane (C4H4F4), and cis-1,1,2,2,3,4-hexafluorocyclobutane (cis-C4H2F6), or a combination thereof; · Introduces iodine-containing etching compounds separately from additional etching gases; adding about 0.01% v / v to about 99.99% v / v of additional etching gas to the iodine-containing etching compound; · Applying RF power to activate the plasma; Activating the plasma with RF power ranging from about 25 W to about 100,000 W; The etching pressure is in the range of about 1 mTorr to about 10 Torr; The etching pressure is 30 mTorr; introducing an iodine-containing etching compound at a flow rate ranging from about 0.1 sccm to about 1 slm; · Maintaining the substrate at a temperature in the range of about -196°C to about 500°C; · Maintaining the substrate at a temperature in the range of about -120°C to about 300°C; · Maintaining the substrate at a temperature in the range of about -100°C to about 50°C; maintaining the substrate at a temperature in the range of about -10°C to about 40°C; and ·Measurement of iodine-containing etching compounds in plasma by quadrupole mass spectrometry, optical emission spectroscopy, FTIR, or other radical / ion measurement tools.

[0011] Also disclosed is a method for forming a patterned structure on a substrate while reinforcing, strengthening, and minimizing damage to a patterned mask layer, the method comprising: A reaction chamber containing a substrate having a silicon-containing film deposited thereon and a patterned mask layer deposited on the silicon-containing layer is charged with a compound of formula C. n H x F y I z introducing vapor of an iodine-containing etching compound having the formula: where 4≦n≦10, 0≦x≦21, 0≦y≦21, and 1≦z≦4; etching the silicon-containing film through the patterned mask layer using an activated iodine-containing etching compound formed by activating the plasma to form a patterned structure; Including, The activated iodine-containing etching compound generates iodine ions that are implanted into the patterned hard mask layer, thereby strengthening the patterned mask layer. The disclosed method can include one or more of the following aspects: The iodine-containing etching compound is a fluorine-containing hydrocarbon compound; · The iodine-containing etching compound is a fluorocarbon compound; · The iodine-containing etching compound is an organic fluorine compound; · The iodine-containing etching compound is a hydrocarbon compound; · Activated iodine-containing etching compounds generate iodine ions that reinforce the patterned mask layer; Iodine-containing etching compounds include C4F9I and C5F 11 I, C6F 13 I, C7F 15 I, C8F 17 I, C9F 19 I C 10 F 21 I, or an isomer thereof; and The iodine-containing etching compound is C4F9I or its isomers.

[0012] Also disclosed is a method for increasing the etching resistance of a patterned mask layer by doping the patterned mask layer with iodine and / or modifying the surface of the patterned mask layer with iodine in a process for forming a patterned structure on a substrate, the method comprising: Vapor of an iodine-containing etching compound is introduced into a reaction chamber containing a substrate having a silicon-containing film disposed thereon and a patterned mask layer disposed on the silicon-containing layer, the vapor being in the form of a compound of formula C. n H x F y I z introducing vapor of an iodine-containing etching compound having the formula: where 4≦n≦10, 0≦x≦21, 0≦y≦21, and 1≦z≦4; activating the plasma to produce an activated iodine-containing etching compound capable of doping the patterned mask layer with iodine, thereby modifying the patterned mask layer with iodine to increase the etch resistance of the patterned mask layer; and etching the silicon-containing film through the patterned mask layer to form a patterned structure while implanting iodine ions from the activated iodine-containing etching compound into the patterned mask layer; The disclosed method may include one or more of the following aspects: The iodine-containing etching compound is a fluorine-containing hydrocarbon compound; · The iodine-containing etching compound is a fluorocarbon compound; · The iodine-containing etching compound is a hydrocarbon compound; · The iodine-containing etching compound is an organic fluorine compound; Iodine-containing etching compounds include C4F9I and C5F 11 I, C6F 13 I, C7F 15 I, C8F 17 I, C9F 19 I C 10 F 21 I, or an isomer thereof; The iodine-containing etching compound is C4F9I or its isomers; etching the silicon-containing film from the substrate to form the patterned structure while implanting iodine ions from the activated iodine-containing etching compound into the surface and / or bulk of the patterned mask layer; etching the silicon-containing film from the substrate to form the patterned structure while implanting iodine ions from the activated iodine-containing etching compound into the surface of the patterned mask layer; The silicon-containing film is etched from the substrate to form the patterned structure while implanting iodine ions from an activated iodine-containing etching compound into the bulk of the patterned mask layer.

[0013] Labeling and Nomenclature In the following detailed description and claims, we generally utilize a number of abbreviations, symbols, and terms that are well known in the art. While definitions are typically provided with each acronym, for convenience, Table 1 provides a list of the abbreviations, symbols, and terms used, along with their respective definitions.

[0014] [Table 1]

[0015] [Table 2]

[0016] As used herein, the indefinite article "a" or "an" means one or more.

[0017] As used herein, "about" or "approximately" or "approximately" in the text or claims means ±10% of the stated value.

[0018] As used herein, "room temperature" in the text and claims means about 20°C to about 25°C.

[0019] The term "ambient temperature" means an environmental temperature of about 20°C to about 25°C.

[0020] The term "substrate" refers to one or more materials on which a process is performed. A substrate may refer to a wafer having one or more materials on which a process is performed. A substrate may be any suitable wafer used in the manufacture of semiconductor, photovoltaic, flat panel, or LCD-TFT devices. A substrate may also have one or more layers of different materials already deposited thereon from a previous manufacturing step. For example, a wafer may include a silicon layer (e.g., crystalline, amorphous, porous, etc.), a silicon-containing layer (e.g., SiO2, SiN, SiON, SiC, SiCN, SiOCN, SiCOH, etc.), a metal-containing layer (e.g., copper, cobalt, ruthenium, tungsten, manganese, platinum, palladium, nickel, ruthenium, gold, etc.), or a combination thereof. Furthermore, a substrate may be flat or patterned. A substrate may also be an organic-patterned photoresist film. The substrate may include an oxide layer (e.g., ZrO2-based materials, HfO2-based materials, TiO2-based materials, rare earth oxide-based materials, ternary oxide-based materials, etc.) used as a dielectric material in MEMS, 3D NAND, MIM, DRAM, or FeRam device applications, or a nitride-based film (e.g., TaN, TiN, NbN) used as an electrode. Those skilled in the art will recognize that the terms "film" or "layer" as used herein refer to a thickness of any material disposed on or extending over a surface, which may be a trench or line. Throughout this specification and claims, the wafer and associated layers thereon are referred to as the substrate.

[0021] The term "wafer" or "patterned wafer" refers to a wafer having a stack of silicon-containing films on a substrate and a patterned hard mask layer on the silicon-containing film stack formed for pattern etching.

[0022] The terms "pattern etching" or "patterned etching" refer to etching a non-planar structure, such as a patterned mask layer on a stack of silicon-containing films.

[0023] As used herein, the terms "etch" or "etching" refer to the use of plasma to remove material through ion bombardment, remote plasma, or 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, resulting in the removal of a portion of the material on the substrate. This type of etching process includes chemical dry etching, gas-phase chemical etching, and thermal dry etching. Isotropic etching processes produce lateral or horizontal etching profiles in the substrate. Isotropic etching processes produce recesses or horizontal recesses in the sidewalls of pre-formed apertures in the substrate. Anisotropic etching processes include plasma etching processes (i.e., dry etching processes) in which ion bombardment accelerates chemical reactions vertically, resulting in the formation of vertical 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 in the substrate. The plasma etching process creates vertical vias, apertures, trenches, channel holes, gate trenches, stepped contacts, capacitor holes, contact holes, slit etching, self-aligned contacts, self-aligned vias, supervias, etc. in the substrate.

[0024] The term "mask" refers to a layer that resists etching. A mask layer can be placed over a layer to be etched. Mask layer also refers to a hard mask layer.

[0025] The term "etch stop" refers to a layer below the layer being etched that protects the layer below.

[0026] The term "device channel" refers to a layer that is part of the actual device, and any damage to it will affect device performance.

[0027] The term "aspect ratio" refers to the ratio of the height of a trench (or via) to the width of the trench (or diameter of a via).

[0028] The term "selectivity" refers to the ratio of the etch rate of one material to the etch rate of another material. The terms "selective etch" or "selective etching" refer to etching one material over another, or in other words, an etch selectivity between two materials that is greater than or less than 1:1.

[0029] The term "independently," when used in reference to describing an R group, should be understood to mean that the R group in question is selected not only independently from other R groups having the same or different subscripts or superscripts, but also independently from any additional species of the same R group. For example, the formula MR 1 x (NR 2 R 3 ) (4-x) In the above, two or three R 1 The groups may be mutually exclusive or R 2 or R 3 Furthermore, unless otherwise specified, it should be understood that the values ​​of R groups are independent of each other when used in different formulas.

[0030] It should be noted that the terms "film" and "layer" may be used interchangeably herein. It is understood that a film may correspond to or relate to a layer, and that a layer may be referred to as a film. Furthermore, those skilled in the art will recognize that the terms "film" or "layer," as used herein, refer to a thickness of some material applied or spread over a surface, and that the surface may range from as large as an entire wafer to as small as a trench or line.

[0031] It should be noted that the terms "etching compound" and "etching gas" may be used interchangeably herein, and it is understood that an etching compound may correspond to or relate to an etching gas, and an etching gas may refer to an etching compound.

[0032] The terms "via," "aperture," "trench," and "hole" are sometimes used interchangeably and generally refer to an opening in an interlayer dielectric.

[0033] 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 the gate structures are stacked vertically.

[0034] Standard abbreviations for elements from the periodic table are used herein. It should be understood that elements can be represented by these abbreviations (e.g., Si means silicon, N means nitrogen, O means oxygen, C means carbon, H means hydrogen, F means fluorine, etc.).

[0035] Unique CAS Registry Numbers (i.e., "CAS") assigned by the Chemical Abstract Service are provided to assist in better identifying the disclosed molecules.

[0036] It should be noted that silicon-containing films such as silicon nitride and silicon oxide are recited throughout the specification and claims without indicating their appropriate stoichiometry. Silicon-containing films include pure silicon (Si) layers such as crystalline Si, polysilicon (p-Si or polycrystalline Si), or amorphous silicon; silicon nitride (Si k N l ) layer; silicon oxide (Si n O m ) layer; or a mixture thereof, where k, l, m, and n are inclusively in the range of 0.1 to 6. Preferably, the silicon nitride is a Si nitride, where k and l are each in the range of 0.5 to 1.5. k N l More preferably, the silicon nitride is Si3N4. Preferably, the silicon oxide is SiN4, where n is in the range of 0.5 to 1.5 and m is in the range of 1.5 to 3.5. n O m More preferably, the silicon oxide is SiO2. In this specification and the following, SiN and SiO respectively represent Si k N l and Si n O m The term "containing layer" is used to refer to a silicon-containing film. The silicon-containing film can also be a silicon oxide-based dielectric material, such as an organic-based or silicon oxide-based low-k dielectric material, such as Black Diamond II or III material from Applied Materials, Inc., which comprises SiOCH. The silicon-containing film can include SiaObCcNdHe, where a, b, c, d, and e range from 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.

[0037] Ranges may be expressed herein as from about one particular value and / or to about another particular value. When such a range is expressed, it should be understood that another embodiment is from the one particular value and / or to the other particular value, along with all combinations within said ranges.

[0038] References herein to "one embodiment" or "an embodiment" mean that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of the invention. The appearances of the phrase "in one embodiment" in various places throughout this specification do not necessarily all refer to the same embodiment, and different or alternative embodiments are not necessarily mutually exclusive of other embodiments. The same applies to the term "implementation."

[0039] For a better understanding of the nature and objects of the present invention, the following detailed description should be read in conjunction with the accompanying drawings, in which like elements are given the same or similar reference numerals. [Brief explanation of the drawings]

[0040] [Figure 1a] FIG. 1 is a cross-sectional view of an exemplary layer in a 3D NAND stack. [Figure 1b] 1 is a cross-sectional view of exemplary layers in a 3D NAND stack showing polymer deposited on the sidewalls during etching of the 3D NAND stack. [Figure 1c] 1A is a cross-sectional view of an exemplary layer in a 3D NAND stack showing particles generated during etching of alternating SiO / SiN layers of the 3D NAND stack. [Figure 1d] 1A-1C are cross-sectional views of exemplary layers in a 3D NAND stack illustrating selective etching of SiN exposed on sidewalls in the 3D NAND stack. [Figure 2] 1 is a cross-sectional view of an exemplary layer of a DRAM stack. [Figure 3a] 1 is an exemplary layer cross-sectional view showing a photoresist pattern on a SiO insulating layer around a typical transistor device area for creating a transistor structure. [Figure 3b] 3b is a cross-sectional view of the exemplary layers of FIG. 3a after etching of the SiO insulating layer. [Figure 4] 1 is a graph showing the etching rates of SiO, SiN, p-Si, and aC by 1-C3F7I, O2, and Ar. [Figure 5] 1 is a graph showing electron impact ionization energy (eV) versus species concentration (Torr) for C3F7I. [Figure 6] 1 is a graph showing the etching rates of SiO, SiN, p-Si, and aC by 1-C4F9I, O2, and Ar. [Figure 7] a Depth profile of 1-C4F9I on a C substrate. [Figure 8] aC(B) Depth profile of 1-C4F9I on the substrate. [Figure 9] a Depth profile of 1-C4F9I on a C(W) substrate. [Figure 10] 1 is a graph showing the etching rates of SiO, SiN, p-Si, and aC by cC4F8. [Figure 11] 1 is a graph showing the etching rates of SiO, SiN, p-Si, and aC by C4F6. DETAILED DESCRIPTION OF THE INVENTION

[0041] A method is disclosed for plasma etching of semiconductor structures such as channel holes, gate trenches, stepped contacts, capacitor holes, contact holes, high aspect ratio structures, 3D NAND, slit trenches, self-aligned contacts, self-aligned vias, and supervias in silicon-containing films. The disclosed method comprises: i) disposing a compound of formula C in a reaction chamber containing a silicon-containing film on a substrate; n H x F y I z where 4≦n≦10, 0≦x≦21, 0≦y≦21, and 1≦z≦4; ii) introducing an inert gas into the reaction chamber; and iii) activating a plasma to produce an activated iodine-containing etching compound capable of etching a silicon-containing film from a substrate, wherein the inert gas can be Ar, Kr, Xe, N, He, or Ne.

[0042] As shown in the examples below, the iodide ions of the disclosed iodine-containing etching compounds dissociate from the compounds at low energies (eV) (i.e., <20 eV). As a result, 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 can be performed at lower plasma energies. For example, the disclosed iodine-containing etching compounds may be particularly suitable for low-k etching processes where damage is a particular concern because lower plasma energies cause less damage to porous low-k materials surrounding the etch site. The reduced damage to low-k materials may be due to the reduced generation of UV photons and F radicals imparted by the iodine-containing etching compounds. The disclosed iodine-containing etching compounds may also prevent loss of critical dimensions and reduce low-k surface roughness. Additionally, molecules with two iodine atoms may enhance these benefits, but at the expense of reduced volatility due to the size of the iodine atom.

[0043] Iodine (10.5 eV) has a lower ionization threshold than fluorine (17.4 eV) and the inert gases Ar (15.8 eV), Xe (12.1 eV), and Kr (14 eV). Therefore, iodine can be ionized more easily by the plasma than fluorine, and iodine-containing etching compounds can increase plasma density. Iodine is a heavy element (mass 127 amu) and can behave similarly to inert gases in the plasma (e.g., Kr (88 amu) and Xe (131 amu)), accelerating toward the wafer. During etching of high-aspect-ratio structures, the deeper the ions penetrate, the weaker their energy becomes, preventing many ions from reaching the bottom of the trench. However, heavy iodine ions can be accelerated toward the wafer by the applied voltage during the plasma etching process, allowing them to penetrate deeply and etch deep, high-aspect-ratio patterned structures. The ionization threshold of fluorine is useful for maintaining it as a neutral 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 and bombards the surface during the plasma etching process. Furthermore, the bond energy of CI is lower than that of CF, making CI bonds more easily broken in plasma compared to CF bonds. Therefore, iodine ions can be easily doped into aC mask layers. Because iodine is a heavy element, it is easier to implant and penetrate deeper into mask layers than lighter elements. Additionally, due to the weak CI bond and the low ionization threshold of iodine, iodine-containing etching compounds have short or negligible atmospheric lifetimes, making them excellent candidates for reducing the global warming potential caused by perfluorocarbon compounds.

[0044] As noted in the comparative examples below, iodide ions dissociate from the disclosed etching compounds at low eV (i.e., <20 eV). However, iodide ions can be implanted into mask features, such as the surface and / or body / bulk. This implantation can help strengthen the mask features, minimize damage, improve etch resistance, and maintain their shape during the etching process. As shown in the examples below, the composition of the patterned mask is modified after using the disclosed iodine-containing etching compounds. Applicants believe that iodine ions modify the surface and are incorporated into the bulk of the patterned mask layer by increasing cross-linking with organic mask layers (such as amorphous carbon masks). Due to the doping of iodine ions and cross-linking between carbon, iodine, hydrogen, and fluorine atoms, preferably between carbon and iodine, the density of the patterned mask layer increases, thereby making the patterned mask layer stronger. In the following examples, the strengthening effect and improved etch resistance of iodine ions is demonstrated by showing that the etch rate of a patterned mask layer is lower when etched with an iodine-containing etching compound than when etched with conventional etching gases such as cC4F8 and C4F6.

[0045] The disclosed iodine-containing etching compounds have the formula C n H x F y I z where 4≦n≦10, 0≦x≦21, 0≦y≦21, and 1≦z≦4. When x=0, the disclosed iodine-containing etching compounds have the formula C n F y I z where 4≦n≦10, 0≦y≦21, 1≦z≦4, and y+z≦2n+2, and may be hydrogen-free. When n=4, the disclosed iodine-containing etching compounds have the formula CF y I z where 1≦z≦4 and y≦10−z. Exemplary C4 iodine-containing etching compounds that do not contain H include C4F9I, C5F 11 I, C6F 13 I, C7F15 I、C8F 17 I、C9F 19 I、C 10 F 21 I、C4F7I、C5F9I、C6F 11 I、C7F 13 I、C8F 15 I、C9F 17 I、C 10 F 19 I、C4F5I、C5F7I、C6F9I、C7F 11 I、C8F 13 I、C9F 17 I、C 10 F 17 I、C4F8I2、C5F 10 I2、C6F 12 I2、C7F 14 I2、C8F 16 I2、C9F 18 I2、C 10 F 20 I2、C4F6I2、C5F8I2、C6F 10 I2、C7F 12 I2、C8F 14 I2、C9F 16 I2、C 10 F 18 I2、C4F4I2、C5F6I2、C6F8I2、C7F 10 I2、C8F 12 I2、C9F 14 I2、C 10 F 16 I2、C4F7I3、C5F9I3、C6F 11 I3、C7F 13 I3、C8F 15 I3、C9F 17 I3、C 10 F 19 I3、C4F4I3、C5F6I3、C6F8I3、C7F 10 I3、C8F 12 I3、C9F 14 I3、C 10 F 16 I3、C4F3I3、C5F5I3、C6F7I3、C7F9I3、C8F 11 I3、C9F 13 I3、C 10 F 15I3, C4F6I4, C5F8I4, C6F 10 I4, C7F 12 I4, C8F 14 I4, C9F 16 I4, C 10 F 18 I4, C4F4I4, C5F6I4, C6F8I4, C7F 10 I4, C8F 12 I4, C9F 14 I4, C 10 F 16 I4, C4F2I4, C5F4I4, C6F6I4, C7F8I4, C8F 10 I4, C9F 12 I4, C 10 F 14 I4 and their isomers.

[0046] General formula C n F 2n+1 Exemplary disclosed iodine-containing etching compounds without H, having the formula I, where 4≦n≦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. The disclosed general formula: C n F 2n+1 The disclosed iodine-containing etching compounds without H having the formula I, where 4≦n≦10, also include their isomers.

[0047] [Table 3]

[0048] The disclosed iodine-containing etching compounds are suitable for etching silicon oxide (SiO), silicon nitride (SiN), crystalline Si, polysilicon (p-Si or polycrystalline Si), pure silicon (Si) such as amorphous silicon, low dielectric constant SiCOH, SiOCN, SiC, SiON, Si a O b H c C d N e(where a>0; b, c, d, and e≧0), or combinations thereof. The silicon-containing film may include alternating layers of SiO and SiN (ONON) or alternating layers of SiO and p-Si (OPOP). The silicon-containing film may also include dopants such as B, C, P, As, Ga, In, Sn, Sb, Bi, and / or Ge.

[0049] The disclosed iodine-containing etching compounds, when containing H, can increase the etch rate of SiN while maintaining high selectivity to the mask layer, but are not limited to this. The disclosed iodine-containing etching compounds having one H when x=1 have the formula C n HF y I z (wherein 4≦n≦10, 0≦y≦20, 1≦z≦4, and y+z≦2n+1). Exemplary compounds include C4HF8I, C5HF 10 I, C6HF 12 I, C7HF 14 I, C8HF 16 I, C9HF 18 I C 10 HF 20 I, C4HF6I, C5HF8I, C6HF 10 I, C7HF 12 I, C8HF 14 I, C9HF 16 I C 10 HF 18 I, C4HF4I, C5HF6I, C6HF8I, C7HF 10 I, C8HF 12 I, C9HF 14 I C 10 HF 16 I, C4HF7I2, C5HF9I2, C6HF 11 I2, C7HF 13 I2, C8HF 15 I2, C9HF 17 I2, C 10 HF 19 I2, C4HF5I2, C5HF7I2, C6HF9I2, C7HF 11 I2, C8HF 13 I2, C9HF 15 I2, C10 HF 17 I2, C4HF3I2, C5HF5I2, C6HF7I2, C7HF9I2, C8HF 11 I2, C9HF 13 I2, C 10 HF 15 I2, C4HF6I3, C5HF8I3, C6HF 10 I3, C7HF 12 I3, C8HF 14 I3, C9HF 16 I3, C 10 HF 18 I3, C4HF4I3, C5HF6I3, C6HF8I3, C7HF 10 I3, C8HF 12 I3, C9HF 14 I3, C 10 HF 16 I3, C4HF5I4, C5HF7I4, C6HF9I4, C7HF 11 I4, C8HF 13 I4, C9HF 15 I4, C 10 HF 17 I4, C4HF3I4, C5HF5I4, C6HF7I4, C7HF9I4, C8HF 11 I4, C9HF 13 I4, C 10 HF 15 I4, C4HFI4, C5HF3I4, C6HF5I4, C7HF7I4, C8HF9I4, C9HF 11 I4, C 10 HF 13 I4 and their isomers.

[0050] The disclosed iodine-containing etching compounds with two hydrogens when x=2 have the formula C n H2F y I z where 4≦n≦10, 0≦y≦19, 1≦z≦4, and y+z≦2n. Exemplary compounds include C4H2F7I, C5H2F9I, C6H2F 11 I, C7H2F 13 I, C8H2F 15 I, C9H2F 17 I C 10 H2F 19I, C4H2F5I, C5H2F7I, C6H2F9I, C7H2F 11 I, C8H2F 13 I, C9H2F 15 I C 10 H2F 17 I, C4H2F6I2, C5H2F8I2, C6H2F 10 I2, C7H2F 12 I2, C8H2F 14 I2, C9H2F 16 I2, C 10 H2F 18 I2, C4H2F4I2, C5H2F6I2, C6H2F8I2, C7H2F 10 I2, C8H2F 12 I2, C9H2F 14 I2, C 10 H2F 16 I2, C4H2F5I3, C5H2F7I3, C6H2F9I3, C7H2F 11 I3, C8H2F 13 I3, C9H2F 15 I3, C 10 H2F 17 I3, C4H2F3I3, C5H2F5I3, C6H2F7I3, C7H2F9I3, C8H2F 11 I3, C9H2F 13 I3, C 10 H2F 15 I3, C4H2F4I4, C5H2F6I4, C6H2F8I4, C7H2F 10 I4, C8H2F 12 I4, C9H2F 14 I4, C 10 H2F 16 I4, C4H2F2I4, C5H2F4I4, C6H2F6I4, C7H2F8I4, C8H2F 10 I4, C9H2F 12 I4, C 10 H2F 14 I4 and their isomers.

[0051] The disclosed iodine-containing etching compounds having three hydrogens when x=3 have the formula C n H3F y I zwhere 4≦n≦10, 0≦y≦18, 1≦z≦4, and y+z≦2n−1. Exemplary compounds include C4H3F6I, C5H3F8I, C6H3F 10 I, C7H3F 12 I, C8H3F 14 I, C9H3F 16 I C 10 H3F 18 I, C4H3F4I, C5H3F6I, C6H3F8I, C7H3F 10 I, C8H3F 12 I, C9H3F 14 I C 10 H3F 16 I, C4H3F5I2, C5H3F7I2, C6H3F9I2, C7H3F 11 I2, C8H3F 13 I2, C9H3F 15 I2, C 10 H3F 17 I2, C4H3F3I2, C5H3F5I2, C6H3F7I2, C7H3F9I2, C8H3F 11 I2, C9H3F 13 I2, C 10 H3F 15 I2, C4H3F4I3, C5H3F6I3, C6H3F8I3, C7H3F 10 I3, C8H3F 12 I3, C9H3F 14 I3, C 10 H3F 16 I3, C4H3F2I3, C5H3F4I3, C6H3F6I3, C7H3F8I3, C8H3F 10 I3, C9H3F 12 I3, C 10 H3F 14 I3, C4H3F3I4, C5H3F5I4, C6H3F7I4, C7H3F9I4, C8H3F 11 I4, C9H3F 13 I4, C 10 H3F 15 I4, C4H3F1I4, C5H3F3I4, C6H3F5I4, C7H3F7I4, C8H3F9I4, C9H3F 11 I4, C 10 H3F 13 I4 and their isomers.

[0052] The disclosed iodine-containing etching compounds having four hydrogens when x=4 have the formula C n H4F y I z where 4≦n≦10, 0≦y≦17, 1≦z≦4, and y+z≦2n−2. Exemplary compounds include C4H4F5I, C5H4F7I, C6H4F9I, C7H4F 11 I, C8H4F 13 I, C9H4F 15 I C 10 H4F 17 I, C4H4F3I, C5H4F5I, C6H4F7I, C7H4F9I, C8H4F 11 I, C9H4F 13 I C 10 H4F 15 I, C4H4F4I2, C5H4F6I2, C6H4F8I2, C7H4F 10 I2, C8H4F 12 I2, C9H4F 14 I2, C 10 H4F 16 I2, C4H4F2I2, C5H4F4I2, C6H4F6I2, C7H4F8I2, C8H4F 10 I2, C9H4F 12 I2, C 10 H4F 14 I2, C4H4F3I3, C5H4F5I3, C6H4F7I3, C7H4F9I3, C8H4F 11 I3, C9H4F 13 I3, C 10 H4F 15 I3, C4H4FI3, C5H4F3I3, C6H4F5I3, C7H4F7I3, C8H4F9I3, C9H4F 11 I3, C 10 H4F 13 I3, C4H4F2I4, C5H4F4I4, C6H4F6I4, C7H4F8I4, C8H4F 10 I4, C9H4F 12 I4, C 10 H4F 14 I4, C4H4I4, C5H4F2I4, C6H4F4I4, C7H4F6I4, C8H4F8I4, C9H4F 10 I4, C10 H4F 12 I4 and their isomers.

[0053] Applicants believe that molecules with four or more carbon atoms can provide better etch rates and sidewall protection during the etching process than molecules with fewer than four carbons, such as a straighter profile, no bends, no tapers, no kinks, no incomplete etching, and no variations in critical dimensions from the top to the bottom of the etched structure. Applicants also believe that molecules with four or more carbon atoms can provide a straighter profile, free of bends, tapers, kinks, and incomplete etching or variations in critical dimensions from the top to the bottom of the etched structure, than molecules with fewer than four carbons. Applicants believe that molecules with four or more carbons create a thicker passivation layer and are therefore preferred for sidewall protection.

[0054] The disclosed iodine-containing etching compounds can provide high selectivity to mask layers, photoresists, etch stop layers, and device channel materials, and can provide no profile distortion in high aspect ratio (HAR) structures, such as DRAM and 3D NAND structures, having aspect ratios ranging from 1:1 to 200:1. Instead, the disclosed iodine-containing etching compounds can provide high selectivity to mask layers or silicon-containing films, such as those having aspect ratios ranging from 1:1 to 200:1, in contact etching applications.

[0055] The disclosed iodine-containing etching compounds can provide numerous selectivities over a wide range of etching process conditions. As used herein, selectivity refers to the ratio of the etch rates of two different layers. For example, the selectivity for a SiO layer to an aC layer is the etch rate of SiO divided by the etch rate of the aC layer. The disclosed iodine-containing etching compounds can provide improved selectivity between silicon-containing films and mask materials, reduced damage to the channel region, improved critical dimension uniformity, and reduced profile distortions such as bowing, kinking, tapering, notches, and undercuts, while maintaining the same critical dimensions from the top to the bottom of the etched structure and arcing to pattern high aspect ratio structures. The disclosed iodine-containing etching compounds can also etch through alternating layers of p-Si, SiO, and / or SiN, resulting in vertical etch profiles (i.e., exhibiting selectivities ranging from 2:1 to 1:2 between alternating layers). A plasma of the disclosed iodine-containing etching compound etches alternating layers of SiO and SiN(ONON) with a selectivity of about 1:2 to about 2:1 for the SiO layers to the SiN layers. Preferably, a plasma of the disclosed iodine-containing etching compound etches alternating layers of SiO and SiN(ONON) with a selectivity of about 1:1 for the SiO layers to the SiN layers.

[0056] The disclosed iodine-containing etching compounds are provided with a purity greater than 95% v / v, preferably greater than 99.99% v / v, and more preferably greater than 99.999% v / v. The disclosed iodine-containing etching compounds contain less than 5% by volume of trace gas impurities, including impurity gases such as N2 and / or HO and / or CO2, at less than 150 ppm by volume. Preferably, the water content in the plasma etching gas is less than 20 ppm by weight. Purified products can be produced by distillation and / or passing the gas or liquid through a suitable adsorbent, such as a 4 Å molecular sieve.

[0057] The disclosed iodine-containing etching compounds contain 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 of any of its isomers, which can be purified by distillation of the gas or liquid to remove the isomers and provide better process repeatability.

[0058] Alternatively, the disclosed iodine-containing etching compounds can contain 0.01% v / v to 99.99% v / v of a target isomer, particularly if the isomer mixture provides improved process parameters or if isolation of the target isomer is very difficult or expensive. For example, the disclosed iodine-containing etching compounds can include about 50% v / v to about 75% v / v of 1-iodononafluorobutane, about 25% v / v to about 50% v / v of 2-iodononafluorobutane, and about 25% v / v to about 50% v / v of iodononafluoro-t-butane. The isomer mixture can also reduce the need for two or more gas lines to the reaction chamber.

[0059] Some of the disclosed iodine-containing etching compounds are gaseous at room temperature and pressure. For non-gaseous (i.e., liquid or solid) compounds, their gaseous form can be generated by vaporizing the compound through a conventional vaporization step, such as direct evaporation, or by bubbling with an inert gas (N, Ar, He, etc.). The non-gaseous compound can be provided in liquid form to a vaporizer, which vaporizes it before introducing it into the reactor.

[0060] The disclosed iodine-containing etching compounds are suitable for plasma etching of semiconductor structures such as channel holes, gate trenches, stepped contacts, slits, capacitor holes, contact holes, self-aligned contacts, self-aligned vias, and supervias in silicon-containing films. Because the disclosed iodine-containing etching compounds induce no or only slight damage to masks with good profiles for high-aspect ratio structures, the disclosed 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 iodine-containing etching compounds can create vertical etched patterns with minimal or no distortion, pattern collapse, or roughness. To achieve these properties, the disclosed iodine-containing etching compounds may deposit an etch-resistant polymer layer during etching to help reduce the direct effects of oxygen and fluorine radicals during the etching process. The disclosed iodine-containing etching compounds can reduce damage to p-Si or crystalline Si channel structures during etching.

[0061] The disclosed iodine-containing etching compounds selectively etch silicon-containing layers from buried landing layers or materials, which in most applications are metal layers located at the bottom of the structure being etched. The disclosed iodine-containing etching compounds do not etch metal landing layers. The buried landing layer may be an etch stop layer or a diffusion barrier layer. The material of the metal landing layer can be the tungsten metal world lines of the 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 etch stop layer such as a metal or metal oxide or nitride layer (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 a combination thereof). The disclosed iodine-containing etching compounds induce little or no damage to the material at the bottom of the contact holes, steps, and slits (such as the tungsten metal world lines of 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 etch stop layer such as a metal or metal oxide or nitride layer (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 a combination thereof). Those skilled in the art will recognize that the barrier layer can also be composed of combinations of the aforementioned metals and metal oxides and nitrides, such as Ti / TiN, Ti / TiN / Ti, TiZrN, Ta / TaN, TaN / Cu / TaN, TaN / Ru / TaN, etc. The barrier can also include silicides (such as TiSiN, TaSiN, TiSi2, MnSiO), phosphides (such as CuWP, NiMoP, NiP), carbides (such as TaC, TaCN, WCN), borides (such as NiMoB, NiB), or combinations thereof.Preferably, the disclosed iodine-containing etching compounds are suitably volatile and stable during the etching process for delivery into the reactor / chamber.

[0062] Materials compatibility testing is important to determine whether any of the disclosed iodine-containing etching compounds react with chamber materials and degrade chamber performance over short or long-term use. Important materials associated with some chambers, valves, and the like include stainless steel, aluminum, nickel, PCTFE, PVDF, PTFE, PFA, PP, Kalrez, Viton, and other metals and polymers. Sometimes, these materials are exposed to high temperatures (e.g., temperatures greater than 20°C) and high pressures (e.g., pressures greater than 1 atm), which can enhance their degradation. Measurement methods can include visual inspection, weight measurement, measuring nanometer-scale changes in scanning electron microscopy (SEM), tensile strength, hardness, and the like.

[0063] The disclosed iodine-containing etching compounds can be used to plasma etch silicon-containing films on substrates. The disclosed plasma etching methods can be useful in the fabrication 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, fork-sheet FETs, complementary FETs (CFETs), bulk complementary metal-oxide semiconductor (Bulk CMOS), MOSFETs, and fully depleted silicon-on-insulator (FD-SOI) structures. The disclosed iodine-containing etching compounds can be useful in other areas of application, such as different front-end of the line (FEOL) and back-end of the line (BEOL) etching applications. Furthermore, the disclosed iodine-containing etching compounds can be used to interconnect memory to logic on substrates, to etch Si in 3D through-silicon via (TSV) etching applications, and in MEMS applications.

[0064] The plasma etching method includes providing a reaction chamber having a substrate disposed therein. The reaction chamber can be any enclosure or chamber in a device in which an etching method is performed, such as, but not limited to, a reactive ion etch (RIE), a capacitively coupled plasma (CCP) with a single or multiple frequency RF source, an inductively coupled plasma (ICP), or a microwave plasma reactor, or any other type of etching system capable of selectively removing portions of a silicon-containing film or generating activated species. Those skilled in the art will recognize that different plasma reaction chamber designs provide different electronic temperature control. Suitable commercially available plasma reaction chambers include, but are not limited to, the Applied Materials magnetically enhanced reactive ion etcher sold under the eMAX™ trademark or the Lam Research Dual CCP reactive ion etcher dielectric etching product line sold under the 2300® Flex™ trademark. RF power therein can be intermittent to control plasma characteristics and thereby further improve etching performance (selectivity and damage).

[0065] Alternatively, plasma-treated reactants can be generated outside the reaction chamber. MKS Instruments' ASTRONi® reactive gas generator can be used to treat reactants prior to passage into the reaction chamber. Operating at 2.45 GHz, 7 kW plasma power, and pressures ranging from about 0.5 Torr to about 10 Torr, the reactant O can decompose into two O radicals. Preferably, the remote plasma can be generated at a power ranging from about 1 kW to about 10 kW, more preferably from about 2.5 kW to about 7.5 kW.

[0066] The reaction chamber may contain one or more substrates. For example, the reaction chamber may contain 1 to 200 silicon wafers with diameters ranging from 25.4 mm to 450 mm. The substrates 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 wafers may have multiple films or layers thereon from previous manufacturing steps, including silicon-containing films or layers. The layers may be patterned or unpatterned. Examples of suitable layers include, but are not limited to, silicon (amorphous silicon, p-Si, crystalline silicon, any of which may be further p-doped or n-doped with B, C, P, As, Ga, In, Sn, Sb, Bi, and / or Ge), silica, silicon nitride, silicon oxide, silicon oxynitride, Si a O b H c C d N e (wherein a>0; b, c, d, e≧0), Ge, SiGe, GeSn, InGaAs, GaSb, InP; mask layer materials such as 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; silicon nitride, polysilicon, crystalline silicon, silicon carbide, SiON, SiCN, or combinations thereof, device channel materials such as crystalline silicon, epitaxial silicon, doped silicon, Si a O b H c C d N e(wherein a>0; b, c, d, e≧0) or a combination thereof. The silicon oxide layer may form a dielectric material such as an organic-based or silicon oxide-based low-k dielectric material (e.g., porous SiCOH film). Exemplary low-k dielectric materials are sold by Applied Materials under the trade name Black Diamond II or III. Furthermore, layers containing tungsten or noble metals (e.g., platinum, palladium, rhodium, or gold) may be used. Further, examples of silicon-containing films include Si a O b H c C d N e where a>0; b, c, d, e≧0. Throughout the specification and claims, the wafer and any associated layers thereof are referred to as the substrate.

[0067] The following are exemplary embodiments of substrates to which the disclosed iodine-containing etching compounds may be applied to etch.

[0068] In one embodiment, a substrate 100 can include a stack of multiple layers, as shown in Figure 1a, which 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 TCAT technology). In some applications, the wafer 102 may be a buried landing layer or material, such as tungsten metal world lines of 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 etch stop layer or diffusion barrier layer, such as a metal or 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). Those 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 combinations of the aforementioned metals and metal oxides and nitrides. The barrier may also include a silicide (e.g., TiSiN, TaSiN, TiSi2, MnSiO), a phosphide (e.g., CuWP, NiMoP, NiP), a carbide (e.g., TaC, TaCN, WCN), a boride (e.g., NiMoB, NiB), or a combination thereof. Those skilled in the art will recognize that the SiN layer 104b may be replaced by a p-Si layer by some techniques (e.g., SiO / p-Si or p-BICS techniques). A 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 dopants. The hard mask layer 106 may be a CVD, PECVD, ALD, PEALD, or spin-on deposited (SOD) amorphous carbon or doped amorphous carbon, a silicon-containing spin-on mask, or a carbon-containing spin-on mask layer.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. An antireflective coating layer 108 is located on top of the hard mask layer 106. A patterned photoresist layer 110 is located on top of the antireflective coating layer 108. Herein, a SiON layer (not shown) may be present between the antireflective coating layer 108 and the hard mask layer 106 to transfer a pattern in the photoresist layer 110 to the hard mask layer 106 to form a patterned hard mask layer. 1a is provided for exemplary purposes only, and the disclosed 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 alternating SiO / SiN or SiO / p-Si layers 104 in the stack of substrate 100 may vary (i.e., may include more or less than the seven SiO / SiN (104a / 104b) layers described).

[0069] FIG. 1b is a cross-sectional view of an exemplary layer in the 3D NAND stack of FIG. 1a, showing polymer deposited on the sidewalls by etching. The disclosed iodine-containing etching compounds may generate fragments during a plasma process that is suitable for anisotropic etching of the silicon-containing film 104 and depositing an I-containing polymer passivation layer 212 on the sidewalls of the etched structure as shown in FIG. 1b. The difference between FIG. 1b and FIG. 1a is that in FIG. 1b, a via 214 is formed in the substrate 100 by plasma etching using the disclosed iodine-containing etching compounds, which also deposits a polymer passivation layer 212 on the sidewalls of the via 214. The polymer passivation layer 212 also provides smoother sidewalls, less distortion, and less deformation at the bottom of the via 214. However, the polymer passivation layer 212 can be easily removed or cleaned by dry or wet etching chemistries known in the art.

[0070] FIG. 1c is a cross-sectional view of an exemplary layer in the 3D NAND stack of FIG. 1a, illustrating particles 316 generated during etching of alternating SiO / SiN layers in the 3D NAND stack. As shown in FIG. 1c, particles 316 generated on the sidewalls of alternating SiO / SiN (i.e., 104a / 104b) layers 104 can be minimized by using the disclosed iodine-containing etching compound. The difference between FIG. 1c and FIG. 1b is that in FIG. 1c, the exposed alternating SiO / SiN side has particles 316 generated during plasma etching. Applicants do not believe that the disclosed iodine-containing etching compound generates the particles 316 shown in FIG. 1c.

[0071] FIG. 1d is a cross-sectional view of an exemplary layer in the 3D NAND stack of FIG. 1a, illustrating selective isotropic etching of the exposed SiN layer 104b on the sidewalls in the 3D NAND stack after an anisotropic etching process. The exposed SiN sidewalls in the stack 100 can be selectively etched as shown in FIG. 1d by using the disclosed iodine-containing etching compound to selectively break the Si-N bonds in the SiN layer 104b over the Si-O bonds in the SiO layer 104a, forming a selective sidewall SiN etch 418 on the SiO / SiN layer 104 stack in the via 214. The difference between FIG. 1d and FIG. 1b is that in FIG. 1d, the exposed SiN on the alternating SiO / SiN sidewalls is selectively etched by the disclosed iodine-containing etching compound to form the selective sidewall SiN etch 418. Typically, the selective sidewall SiN etch 418 is performed by wet etching using a mixture with phosphoric acid. Because wet etching requires transferring the substrate to a different wet etching apparatus, replacing the wet etching process with a dry plasma etching process is known to significantly improve the economics of the semiconductor device fabrication process. With the disclosed method, all etches, including the selective sidewall SiN etch of FIG. 1d, can be performed in an integrated etching apparatus, which can reduce the cost of semiconductor fabrication.

[0072] In another embodiment, as shown in FIG. 2, a substrate 100 may include a stack of multiple layers thereon. FIG. 2 is a cross-sectional view of exemplary layers in a DRAM stack for creating a DRAM memory. In FIG. 2, a four-layer stack is located on a silicon wafer 102. A hard mask layer 106 is located on top of a large SiO layer 104a. An antireflective coating layer 108 is located on top of the hard mask layer 106. A patterned photoresist layer 110 is located on top of the antireflective coating 108. A SiON layer (not shown) may be present between the antireflective coating layer 108 and the hard mask layer 106 to transfer the pattern in the photoresist layer 110 to the hard mask layer 106. Those skilled in the art will recognize that the layer stack in FIG. 2 is provided for exemplary purposes only, and that the disclosed iodine-containing etching compounds may be used to etch other layer stacks, for example, stacks in which the hard mask layer 106 is replaced by a TiN layer. Additionally, one skilled in the art will recognize that the number of layers in the stack can vary (ie, can include more or fewer layers than those described).

[0073] FIG. 3a is an exemplary layer cross-sectional view showing a photoresist pattern on a SiO insulating layer surrounding a typical transistor device region for creating a transistor structure. Substrate 600, as shown in FIG. 3a, can include a four-layer stack surrounding a transistor gate electrode region supported on a silicon wafer 602. The transistor region shown in FIG. 3a includes two doped silicon regions 606 that act as the source and drain. A transistor gate dielectric 614 resides below gate electrode 616. The entire transistor, i.e., transistor gate dielectric 614 and gate electrode 616, is surrounded by a thin SiN layer 608, which can later act as an etch stop layer during contact etching. Each transistor device region 616 / 606 is separated by a SiO isolation region 604 in silicon wafer 602 to minimize electrical interference. Those skilled in the art will recognize that layer 602 can be located on top of a silicon oxide layer of a silicon-on-insulator (SOI) wafer. Another SiO layer 610 is deposited over the transistor and is used to isolate any metal contacts to the transistor device region 606. A photoresist mask 612 is used to pattern the SiO layer 610. Etching is performed using the disclosed iodine-containing etch chemistry in a plasma environment. As shown in FIG. 3b, the photoresist mask 612 serves as a template for etching the SiO layer 610, and the etching stops on the SiN layer 608.

[0074] Figure 3b is a cross-sectional view of the exemplary layers of Figure 3a after etching of the SiO insulating layer. The difference between Figure 3b and Figure 3a is that in Figure 3b, a via 718 is formed in the SiO layer 610 by etching with the disclosed iodine-containing etching compound. The SiO layer 610 may be etched using a photoresist layer 612 as a mask layer. The mask layer may be any suitable photoresist mask material, such as TiN, aC, etc. The etch may stop at the underlying SiN layer 608.

[0075] The disclosed iodine-containing etch compounds may be used to etch SiN layer 608 using different plasma conditions and different mixtures. Those skilled in the art will recognize that the layer stacks and geometries of Figures 3a and 3b are provided for exemplary purposes only, and that the disclosed iodine-containing etch 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., may include more or fewer than the four layers described).

[0076] Vapor of the disclosed iodine-containing etching compound 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 ranging from about 0.1 sccm to about 1 slm. For example, for a 200 mm wafer diameter, the vapor can be introduced into the chamber at a flow rate ranging from about 5 sccm to about 50 sccm. Alternatively, for a 450 mm wafer diameter, the vapor can be introduced into the chamber at a flow rate ranging from about 25 sccm to about 250 sccm. Those skilled in the art will recognize that flow rates can vary depending on the tool.

[0077] The disclosed iodine-containing etching compounds can be provided either neat or blended with an inert gas or solvent, such as N, Ar, Kr, Ne, He, or Xe. The disclosed iodine-containing etching compounds can be present in various concentrations in the blend. For liquid iodine-containing etching compounds, the vapor form of the iodine-containing etching compound can be generated by evaporating the neat or blended iodine-containing etching compound solution by a conventional evaporation step, such as direct distillation, or by bubbling. The neat or blended iodine-containing etching compound can be provided in a liquid state to an evaporator, which evaporates it before introducing it into the reactor.

[0078] Alternatively, the neat or blended iodine-containing etching compound can be vaporized by passing a carrier gas through a vessel containing the disclosed iodine-containing etching compound or by bubbling a carrier gas through the disclosed iodine-containing etching compound. Carrier gases include, but are not limited to, Ar, He, N2, and mixtures thereof. Bubbling with a carrier gas can remove any dissolved oxygen present in the neat or blended iodine-containing etching compound solution. The carrier gas and the disclosed iodine-containing etching compound are then introduced into the reactor as a vapor.

[0079] If necessary, the vessel containing the disclosed iodine-containing etching compound may be heated to a temperature that allows the iodine-containing etching compound to be in a liquid phase and have sufficient vapor pressure for delivery to the etching tool. The vessel may be maintained at a temperature ranging, for example, from about 0°C to about 150°C, preferably from about 25°C to about 100°C, and more preferably from about 25°C to about 50°C. More preferably, the vessel is maintained at room temperature (about 25°C) to avoid heating the lines to the etching tool. Those skilled in the art will recognize that the temperature of the vessel can be adjusted in a well-known manner to control the amount of iodine-containing compound that is vaporized.

[0080] Additionally, the iodine-containing etching compounds can be delivered in purities ranging from 95% to 99.999% by volume and can be purified by well-known standard purification techniques for the removal of CO, CO, N, HO, HF, HS, SO, halides, and other hydrocarbons or hydrohalocarbons.

[0081] An inert gas is also introduced into the reaction chamber to receive the plasma. The inert gas may be He, Ar, Xe, Kr, Ne, or N. 2、The etching gas may be He, or a combination thereof. The etching gas and the inert gas may be mixed prior to introduction into the chamber such that the inert gas comprises from 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 into the chamber intermittently.

[0082] The disclosed etching gas vapor and inert gas are activated by plasma to produce activated etching gas. The plasma decomposes the etching gas into radical form (i.e., activated etching gas). The plasma may be generated by applying RF or DC power. The plasma may be generated by RF power ranging from about 25 W to about 100,000 W. The plasma may be generated remotely or within the reactor itself. The plasma may be generated in dual CCP or ICP mode with RF applied at both electrodes. The RF frequency of the plasma may range from 100 KHz to 1 GHz. Different RF sources at different frequencies may be combined and applied at the same electrode. Plasma RF pulsing may also be used to control molecular fragmentation and reaction at the substrate. Those skilled in the art will recognize suitable methods and apparatus for such plasma processing.

[0083] The activated etching gas from the chamber exhaust may be measured by 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.

[0084] The disclosed etching gases may be mixed with other gases either prior to introduction into the reaction chamber or in the reaction chamber. Preferably, the gases are mixed prior to introduction into the chamber to provide a uniform concentration of the entrained gases.

[0085] In another option, the vapor of the iodine-containing compound may be introduced into the chamber independently from other gases, such as when two or more gases react or are easier to deliver independently.

[0086] In another option, the etching gas and the inert gas are the only two gases used during the etching process.

[0087] Exemplary other gases include, but are not limited to, oxidizers such as O2, O3, CO, CO2, NO, N2O, NO2, H2O, H2O2, COS, SO2, and combinations thereof. The disclosed etching gases and oxidizers may be mixed together before being introduced into the reaction chamber.

[0088] Alternatively, the oxidizer can be continuously introduced into the chamber and the etching gas intermittently introduced into the chamber. The oxidizer may comprise from about 0.01% v / v to about 99.99% v / v of the mixture introduced into the chamber (99.99% v / v represents the introduction of nearly pure oxidizer for the continuous introduction option).

[0089] Other exemplary gases with which the disclosed iodine-containing etching compounds may be used include cC4F8, C4F8, cC5F8, C5F8, C4F6, CF4, CH3F, CF3H, CH2F2, C3HF7, C3F6, C3H2F6, C3H2F4, C3H3F5, C4HF7, C5HF9, C3F6, C3F8, CF3I, C2F3I, C2F5I, C3F7I, 1-iodoheptafluoropropane (1-C3F7I), 2-iodoheptafluoropropane (2-C3F7I), C3HF7, COS, FNO, FC≡N, CS2, SO2, SF6, trans-1,1,1,4, Examples of suitable iodine-containing etching compounds include 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, about 1% v / v to about 25% v / v of the disclosed iodine-containing etching compounds may be used, with the remainder being C4F6 or cC4F8. As shown in the examples below, the combination of the disclosed iodine-containing etching compounds with conventional etching gases can result in increased etch rates while maintaining higher selectivity between the substrate and the layer being etched in conjunction with the disclosed iodine-containing etching compounds.

[0090] The vapor of the disclosed iodine-containing etching compound and the etching gas may be mixed prior to introduction into the reaction chamber, and the additional etching gas may comprise from about 0.01% v / v to about 99.99% v / v of the mixture introduced into the chamber.

[0091] In one non-limiting plasma etching process, vapor of the disclosed iodine-containing compound, such as C4F9I, is introduced into a 200 mm dual CCP plasma etching tool using a controlled gas flow device. The controlled gas flow device can 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., can be used. The pressure of the reaction chamber is set to approximately 30 mTorr. If the vapor pressure is sufficient, heating of the gas source may not be required. The distance between the two CCP electrodes is kept at 1.35 cm, and the top electrode RF power is fixed at 750 W. The bottom electrode RF power is varied to analyze the performance of the molecule. Similar to that shown in Figure 1a, the reaction chamber contains a substrate having a silicon-containing film thereon. The antireflective coating layer 108 is patterned / etched with a fluorocarbon (e.g., CF4 and CH2F2) and an oxygen-containing gas (e.g., O2). The amorphous carbon mask layer is patterned / etched with an oxygen-containing gas. The SiO2 and SiN layer 104 is patterned with a plasma of the disclosed iodine-containing etching compound (e.g., CF4I) and argon. Argon is independently introduced into the chamber at a flow rate of 250 sccm. CF4I is independently introduced into the chamber at 15 sccm. O2 is independently introduced into the chamber and varied from 0 sccm to 20 sccm to determine the optimal etching conditions. Apertures with aspect ratios of 10:1 or greater are fabricated, which can be used for channel holes, contact holes, step etching, slit etching, or in 3D NAND. Similar examples may be used for other stack layers, such as those shown in Figures 2 and 3a.

[0092] In another non-limiting exemplary plasma etching process, C4F9I is introduced into a 200 mm dual CCP plasma etching tool using a controlled gas flow device. The controlled gas flow device can be a mass flow controller. For high-boiling-point molecules, special low-pressure drop mass flow controllers from Brooks Automation (No. GF120XSD), MKS Instruments, etc. can be used. The pressure in the reaction chamber is set to approximately 30 mTorr. If the vapor pressure is sufficient, gas source heating may not be required. The distance between the two CCP electrodes is kept at 1.35 cm, and the top electrode RF power is fixed at 750 W. The bottom electrode RF power is varied to analyze the performance of C4F9I. The reaction chamber contains a substrate 100 having a thick SiO2 layer 104a thereon, similar to the layer shown in FIG. 2. Prior to this process, the antireflective coating layer 108 is removed with a fluorocarbon (e.g., CF) and an oxygen-containing gas (e.g., O), and the Ac mask layer 106 is removed with an oxygen-containing gas. Argon is independently introduced into the chamber at a flow rate of 250 sccm. C4F9I is independently introduced into the chamber at 15 sccm. O2 is independently introduced into the chamber at 0 sccm to 20 sccm to determine the optimal etching conditions. Apertures with aspect ratios of 10:1 or greater are created, which can be used as contact holes in DRAMs. Similar examples may be used for other stack layers, such as those shown in Figures 1a and 3a.

[0093] The silicon-containing film and the activated iodine-containing etching gas react to form volatile by-products that are removed from the reaction chamber. The aC mask, anti-reflective coating, and photoresist layer are not very reactive to the activated etching gas. Therefore, the activated etching gas selectively reacts with the silicon-containing film to form volatile by-products.

[0094] The temperature and pressure in the reaction chamber are maintained at conditions appropriate for the silicon-containing film to react with the activated etching gas. For example, the pressure in the chamber can be maintained at about 0.1 mTorr to about 1000 Torr, preferably about 1 mTorr to about 10 Torr, more preferably about 10 mTorr to about 1 Torr, and more preferably about 10 mTorr to about 100 mTorr, as required by the etching parameters. Similarly, the substrate temperature in the chamber can range from about -196°C to about 500°C, preferably about -120°C to about 300°C, more preferably about -100°C to about 50°C, and more preferably about -10°C to about 40°C. The chamber wall temperature can range from about -196°C to about 300°C, depending on process requirements.

[0095] The reaction between the silicon-containing film and the activated etching gas results in 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 can be achieved by physical sputtering of the silicon-containing film from plasma ions (enhanced by the plasma) and / or by removing Si from SiF, where x is in the range of 1 to 4. x By chemical reaction of plasma species to convert them into volatile species such as

[0096] The plasma-activated vapor of the disclosed iodine-containing etching compound preferably exhibits high selectivity to the mask and etches through alternating layers of SiO and SiN, resulting in a vertical etch profile without distortion or roughness. This is important for 3D NAND applications. Furthermore, the plasma-activated vapor deposits polymer 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. The plasma-activated etching gases can selectively etch SiO and / or SiN from mask layers such as aC, photoresist, p-Si, or silicon carbide; from metal contact layers such as Cu, W, or Ru; or from channel regions made of SiGe or polysilicon regions.

[0097] The disclosed etching process employs the disclosed iodine-containing etching compounds as etching gases to create channel holes, gate trenches, stepped contacts, capacitor holes, contact holes, contact etch, slit etch, self-aligned contacts, self-aligned vias, supervias, and the like in silicon-containing films. The resulting apertures can have aspect ratios ranging from about 10:1 to about 200:1 and diameters ranging from 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 silicon-containing films with aspect ratios greater than 50:1.

[0098] A typical material that needs to be etched can be SiO. The SiO etching process can involve etching trenches in borophosphosilicate glass (BPSG), tetraethyl orthosilicate (TEOS), or low deposition rate TEOS (LDTEOS). The etch stop layer can be silicon nitride or silicon oxide nitride (SiON) or polysilicon. The mask material used can be aC, p-Si, or photoresist material. The iodine-containing etching compounds disclosed herein can be used to etch SiO, SiN, p-Si, and / or aC substrate films.

[0099] As shown in the examples below, evaluation of dry etching of SiO, SiN, p-Si, and aC films using the disclosed iodine-containing etch compounds demonstrates that iodine-containing HFCs offer the highest selectivity for silicon oxide over amorphous carbon, silicon nitride, and p-Si compared to prior art fluorocarbons. The high selectivity is believed to be due to the formation of low F / C iodine-containing fragments during plasma dissociation of the etch gas, which then form a protective polymer film on the substrate. Furthermore, iodine is ionized, bombarding the surface with heavy I ions, 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 and improving its etch resistance, favoring high aspect ratio etching. The activated iodine-containing etch compounds generate iodine ions that strengthen the patterned mask layer, thereby reinforcing and minimizing damage to the patterned mask layer while forming patterned structures on the substrate. The etching gas results presented herein are not only expected for patterned structure etching processes, such as contact etching processes, but also demonstrate potential benefits for other etching processes on silicon- or metal-containing substrates, including low-k etching processes. Additionally, in processes for forming patterned structures by etching with the disclosed iodine-containing etching compounds, the surface of the patterned mask layer can be doped with iodine to modify the surface, thereby increasing the etch resistance of the patterned mask layer. In this case, iodine ions from the activated iodine-containing etching compound are implanted 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 iodine-containing etching compounds are suitable for reducing the global warming potential caused by perfluorocarbon compounds. [Example]

[0100] The following non-limiting examples are provided to further illustrate embodiments of the present invention, however, the examples are not intended to be comprehensive and are not intended to limit the scope of the invention described herein.

[0101] In the following examples, experiments were performed using a commercially available LAM tool 4520XLe 200 mm (CCP Dual Frequency Plasma) or a commercially available AMEC 300 mm Primo SSC HD-RIE etcher. Flat wafers were purchased from Advantive Tech. The flat wafers tested were four different substrates: 2um PECVD TEOS(SiO ) on Si substrate; 2um PECVD Si3N4 (SiN) on Si substrate; 300 nm of LPCVD polysilicon (poly-Si) on a Si substrate; and 350 PECVD amorphous carbon (aC) on Si substrate.

[0102] For planar tests, the etching rate (ER) was measured by measuring the change in etched thickness as a function of etching time using an ellipsometer and / or a scanning electron microscope (SEM). Etching experiments were performed on four 1.5 × 1.5 cm square wafers with four different substrate materials, including SiO, SiN, p-Si, and aC, as listed above. 2 The coupons were placed on a 200 mm diameter carrier wafer and held in contact using silicone oil or thermal paste. Alternatively, double-sided carbon tape, available from the 2spi manufacturer, may be used to attach the coupons to the carrier wafer.

[0103] Etching tests were performed at a pressure of 30 mTorr, a source power 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 Ar and 15 sccm etch gas, while O was varied from 0 to 20 sccm.

[0104] To demonstrate reproducibility, each etching test was repeated at least three times. The standard deviation of the mean of the triplicate measurements is shown as the error bars in the chart. The composition of the polymer was then investigated by X-ray photoelectron spectroscopy (XPS).

[0105] Comparative Example Figure 4 is a graph showing the etch rates of SiO, SiN, p-Si, and aC using 1-C3F7I (CAS No. 754-34-7), O2, and Ar. In Figure 4, the y-axis represents the etch rate; the x-axis represents the O2 flow rate in sccm. The O2 flow rate is varied from 0 to 20 sccm, while the 1-C3F7I flow rate is fixed at 15 sccm and the Ar flow rate is fixed at 250 sccm. As the O2 flow rate increases from 0 to 20 sccm, an inversely proportional trend is observed; while increasing the O2 flow rate decreases the erosion rate of SiO2, increasing the O2 flow rate increases the erosion rate of SiN, p-Si, and aC. Therefore, the highest selectivity, i.e., the ratio of the erosion rate of SiO to the erosion rate of other materials, is observed when oxygen is not flowing. At 0 sccm of O2, the SiO2 / aC selectivity is 38.5, the SiO2 / p-Si selectivity is 22, and the SiO2 / SiN selectivity is 11.

[0106] Figure 5 is a graph showing electron impact ionization energy (eV) versus species concentration (Torr) for C3F7I. The main fragments produced between 10 and 20 eV are CF3, C3F7, and I.

[0107] Example 1 Figure 6 is a graph showing the etch rates of SiO, SiN, p-Si, and aC using 1-C4F9I, O2, and Ar. In Figure 6, the y-axis represents etch rate; the x-axis represents O2 flow rate in sccm; the O2 flow rate is varied from 0 to 20 sccm, while the 1-C4F9I flow rate is fixed at 15 sccm and the Ar flow rate is fixed at 250 sccm.

[0108] An inverse trend is observed as the O2 flow rate increases from 0 to 20; while increasing the O2 flow rate decreases the ER of SiO2, increasing the O2 flow rate increases the ER of SiN, p-Si, and aC. Therefore, the highest selectivity, i.e., the ratio of the ER of SiO to the ER rate of the other materials, is observed when oxygen is not flowing. At 0 sccm of O2, the SiO2 / aC selectivity is 71, the SiO2 / p-Si selectivity is 47, and the SiO2 / SiN selectivity is 17. Compared to the results for 1-C3F7I shown in Figure 4, 1-C4F9I outperforms all other materials tested in terms of both SiO2 ER and SiO2 selectivity.

[0109] The addition of iodine increases the fragmentation of both 1-C3F7I and 1-C4F9I due to the weaker CI bond. The lower ionization threshold of iodine ions impinging on the surface increases the selectivity for etching oxide (SiO) compared to aC, poly-Si, or SiN. Table 3 compares the selectivity with benchmark standard etching gases cC4F8 and CF4F6 commonly used in industry. 1-C4F9I exhibits higher SiO2 / aC selectivity than the benchmark gases (cC4F8 and CF4F6), approximately 88% and 85%, respectively, and approximately 46% higher than 1-C3F7I. 1-C4F9I also exhibits higher SiO2 ER than the benchmark gases (cC4F8 and CF4F6), 8.6% and 16.4%, respectively, and 9% higher than 1-C3F7I. 10 and 11 are graphs showing the etch rates of SiO, SiN, p-Si, and aC by cC4F8 and C4F6, respectively.

[0110] [Table 4]

[0111] Example 2 XPS data analysis after 1-C4F9I etching on different aC mask layers with and without dopants. XPS angle resolved analysis was performed on the sample tilt at 75° and depth profile to analyze the polymer composition on the aC mask and compare it with the SiO2 substrate.

[0112] To simulate the formation of polymer layers on the top and sidewalls during plasma etching of patterns, process conditions were adjusted: aC mask, boron-doped aC [aC(B)], tungsten-doped aC [aC(W)], and SiO2 (TEOS) coupons were etched at 30 mTorr for 60 seconds with a power supply of 750 W (27 MHz) and a substrate bias power of 1500 W (2 MHz). The process uses a mixture containing 125 sccm Ar and 30 sccm 1-C4F9I, but no O2. Neutral and activated species that reach the surface adhere to the surface based on their sticking coefficients, depositing a thin polymer layer. This thin polymer layer can contribute to sidewall passivation and often provides selectivity. Tables 4-6 show 75°-resolved XPS angles for different aC layers after 1-C4F9I etching.

[0113] [Table 5]

[0114] [Table 6]

[0115] [Table 7]

[0116] The surface atomic concentration of iodine in the three different aC masks [aC, aC(B), aC(W)] corresponds to approximately 2%.

[0117] For XPS depth profiling, monoatomic Ar was used to minimize chemical damage and to avoid the possibility of knock-on of iodine atoms during argon sputtering, which can occur during sputtering of organic materials such as fluoropolymers or amorphous carbon. + Instead, Ar, a cluster ion gas with a large ion energy of 5 keV, is used. 1000 + was used.

[0118] Depth profile on aC substrate: surface atomic concentration (%) is shown in Table 7 and Figure 7. Depth profile on aC(B) substrate: surface atomic concentration (%) is shown in Table 8 and Figure 8. Depth profile on aC(W) substrate: surface atomic concentration (%) is shown in Table 9 and Figure 9. Surface atomic concentration after l-C4F9I etching on SiO2 substrate is shown in Table 10.

[0119] [Table 8]

[0120] [Table 9]

[0121] [Table 10]

[0122] [Table 11]

[0123] The disclosed iodine-containing etching compounds exhibit interesting behavior during aC mask etching compared to etching of Si-based materials: XPS data shows that iodine penetrates deeper into the aC mask, similar to a doping effect, helping to preserve the mask during etching. · In aC, aC(B), and aC(W), iodine was detected at about 2% on the surface and less in the deeper bulk; Surface C x F y I z (x ≤ 4, y ≤ 9, z ≤ 1) polymer was detected in all aC masks (etching up to 50 seconds); Iodine vs. Fluoride Penetration in Different aC Masks: In aC: I penetrates deeper than F (410 vs. 450 s, respectively); In aC(W): I penetrates deeper than F (90 seconds vs. 45 seconds, respectively), · In aC(B): F penetrates deeper than I (210 s vs. 90 s respectively); In comparison, iodine was barely detectable (0.3%) on the SiO2 substrate, and only a very thin FC polymer was formed.

[0124] In this example, iodine ions are C x F y I z The surface of the pattern mask was modified by depositing a polymer layer composed of atoms, demonstrating that iodine ions penetrated deep into the bulk of the pattern mask layer. The effect of iodine ions can be observed by correlating the XPS data on the composition of the pattern mask after etching with the etching data shown in Example 1. The iodine-containing etching compound aids in preserving the pattern mask layer by increasing crosslinking with the organic layer, making the pattern mask stronger and more etch-resistant.

[0125] Although the subject matter described herein may be described in connection with example implementations for processing one or more computing application functions / operations for a computing application having a user-interactive component, the subject matter is not limited to these particular embodiments. Rather, the techniques described herein may be applied to any suitable type of user-interactive component execution management method, system, platform, and / or device.

[0126] It will be understood that many additional changes in the details, materials, steps, and arrangements of parts described and illustrated herein to illustrate the nature of the invention may be made by those skilled in the art within the principles and scope of the invention as set forth in the appended claims. Accordingly, it is not intended that the invention be limited to the specific embodiments in the examples given above and / or in the accompanying drawings.

[0127] While embodiments of the present invention have been shown and described, modifications can be made 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 are 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 scope of the claims, including all equivalents of the subject matter of the claims.

Claims

1. 1. A method of forming a patterned structure, comprising: introducing vapor of an iodine-containing etching compound, C4F9I or an isomer thereof, into a reaction chamber containing a substrate having a silicon-containing film disposed thereon and a patterned mask layer disposed on the silicon-containing film; activating the plasma to produce an activated iodine-containing etching compound; and allowing an etching reaction to proceed between the activated iodine-containing etching compound and the silicon-containing film to selectively etch the silicon-containing film from the patterned mask layer, thereby forming the patterned structure; Including, the silicon-containing film comprises layers of silicon oxide (SiO), silicon nitride (SiN), crystalline Si, polysilicon (p-Si), amorphous silicon, low dielectric constant SiCOH, SiOCN, SiC, SiON, and Si a O b H c C d N e (where a>0; b, c, d, and e≧0), alternating layers of SiO and SiN (ONON), alternating layers of SiO and p-Si (OPOP); The method wherein the plasma of the iodine-containing etching compound that etches the alternating SiO and SiN (ONON) layers has a selectivity of about 1:2 to about 2:1 for SiO layers to SiN layers.

2. The method further includes introducing an oxidizing agent into the reaction chamber, the oxidizing agent being O ２ , O ３ , CO, CO ２ , NO, N ２ O, NO ２ , H ２ O, H ２ O ２ , COS, SO ２ 10. The method of claim 1, wherein the hydroxyl group is selected from the group consisting of:

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

4. The etching rate of the SiO layer using the iodine-containing etching compound is higher than that of the alternative etching gas cC under the same etching conditions. ４ F ８ , C ４ F ６ , C.F. ４ , C.H. ３ F, CF ３ H, CH ２ F ２ 10. The method of claim 1, wherein the etch rate is higher than the etch rate of the SiO layer using SiO.sub.2, ...

5. 10. The method of claim 1, wherein the plasma of the iodine-containing etching compound that etches the alternating SiO and p-Si (OPOP) layers has a selectivity of about 1:2 to about 2:1 for SiO layers to p-Si layers.

6. The method of any one of claims 1 to 3, wherein 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.

7. 4. The method of claim 1, wherein the activated iodine-containing etching compound selectively etches the silicon-containing film from a landing layer located at the bottom of the silicon-containing film being etched, and the landing layer is a metal layer, a metal oxide layer, or a metal nitride layer.

8. 4. The method of claim 1, wherein the patterned structure formed in the silicon-containing film has an aspect ratio of about 1:1 to about 200:

1.

9. 1. A method for forming a patterned structure on a substrate while reinforcing and / or strengthening and / or minimizing damage to a patterned mask layer, comprising: introducing vapor of an iodine-containing etching compound, C4F9I or an isomer thereof, into a reaction chamber containing a substrate having a silicon-containing film deposited thereon and a patterned mask layer deposited on the silicon-containing film; etching the silicon-containing film through the patterned mask layer using an activated iodine-containing etching compound formed by activating a plasma to form the patterned structure; Including, the activated iodine-containing etching compound generates iodine ions that are implanted into the patterned hard mask layer, thereby strengthening the patterned mask layer; the silicon-containing film comprises layers of silicon oxide (SiO), silicon nitride (SiN), crystalline Si, polysilicon (p-Si), amorphous silicon, low dielectric constant SiCOH, SiOCN, SiC, SiON, and Si a O b H c C d N e (where a>0; b, c, d, and e≧0), alternating layers of SiO and SiN (ONON), alternating layers of SiO and p-Si (OPOP); a plasma of the iodine-containing etching compound that etches the alternating SiO and SiN (ONON) layers has a selectivity of about 1:2 to about 2:1 for SiO layers to SiN layers; method.

10. 1. A method for increasing the etch resistance of a patterned mask layer in a process for forming a patterned structure on a substrate, comprising: introducing vapor of an iodine-containing etching compound, wherein the iodine-containing etching compound is C4F9I or an isomer thereof, into a reaction chamber containing a substrate having a silicon-containing film disposed thereon and the patterned mask layer disposed on the silicon-containing film; activating a plasma to produce an activated iodine-containing etching compound capable of doping the patterned mask layer with iodine; and etching the silicon-containing film through the patterned mask layer to form the patterned structure while implanting the iodine ions from the activated iodine-containing etching compound into the patterned mask layer; modifying the patterned mask layer with iodine thereby increasing the etch resistance of the patterned mask layer; Including, the silicon-containing film comprises layers of silicon oxide (SiO), silicon nitride (SiN), crystalline Si, polysilicon (p-Si), amorphous silicon, low dielectric constant SiCOH, SiOCN, SiC, SiON, and Si a O b H c C d N e (where a>0; b, c, d, and e≧0), alternating layers of SiO and SiN (ONON), alternating layers of SiO and p-Si (OPOP); The method wherein the plasma of the iodine-containing etching compound that etches the alternating SiO and SiN (ONON) layers has a selectivity of about 1:2 to about 2:1 for SiO layers to SiN layers.

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