High conductivity passivation layer and method of forming same during high aspect ratio plasma etch

Abstract

Disclosed is a method for forming a high aspect ratio (HAR) structure in a substrate during a HAR etch process in a reaction chamber, the method comprising: sequentially or simultaneously exposing the substrate to a vapor of an etchant comprising a hydrofluorocarbon or fluorocarbon and an additive compound, the substrate is provided with a film arranged on the substrate and a patterned mask layer arranged on the film; activating the plasma to produce an activated hydrofluorocarbon or fluorocarbon and an activated additive compound; and allowing an etch reaction between the film uncovered by the patterned mask layer and the activated hydrofluorocarbon or fluorocarbon and the activated additive compound to selectively etch the film from the patterned mask layer, thereby forming a HAR patterned structure.

Description

[0001] This application is a divisional application of patent application No. 202180093364.7, filed on December 16, 2021, entitled "Highly Conductive Passivation Layer and Method for Forming Thereof During High Aspect Ratio Plasma Etching".

[0002] Cross-reference to related applications

[0003] This application claims the benefit of U.S. Application No. 17 / 135,216, filed December 28, 2020, which is incorporated herein by reference in its entirety for all purposes. Technical Field

[0004] A method is disclosed for forming a highly conductive sidewall passivation layer on the sidewalls by doping with Si, C and / or iodine elements and / or introducing cyclic, aromatic, heterocyclic chemical structures during high aspect ratio (HAR) plasma etching using etching gas as an additive. Background Technology

[0005] For over 50 years, Moore's Law has driven semiconductor manufacturers to continuously shrink device feature sizes to increase transistor / chip speed and capacity while maintaining a cost advantage over competitors. This presents new challenges in manufacturing methodologies to successfully meet the demands of ever-shrinking feature sizes and dramatically increasing aspect ratios. For example, manufacturing three-dimensional gate stacked NAND flash memory (3D-NAND) requires the ability to etch small via features with aspect ratios greater than 40 (through 90+ NAND layers). Over a trillion vias require extremely high aspect ratio (HAR) etching to be etched onto each wafer.

[0006] Vertical isotropy of etched features is achieved through ion transport during plasma shell formation. In principle, positive and negative particles should have identical trajectories within the apertures and balance the charge at the bottom of the HAR apertures. However, due to electron shielding effects, charge accumulates at the bottom of the HAR mask pattern, leading to incomplete etching, bending, twisting, and variations in the critical dimension (CD) between the top and bottom of the HAR stack. Therefore, industry has made numerous efforts and continues to work to remove or minimize sidewall charge accumulation during HAR etching to improve etch profile and CD control.

[0007] It is known that contact hole deformation is caused by asymmetric charging of the contact hole sidewalls, which alters the local electric field within the contact hole and changes the orientation of reacting ions within the contact hole (see Kim et al., J. Vac. Sci. Technol. A, Vol. 33, 021303-5 (2015) and Negishi et al., J. Vac. Sci. Technol. B, Vol. 35, 051205 (2017)). In HAR etching, ellipticity has been used to evaluate mask degradation. Higher ellipticity (closer to 100%) helps avoid HAR hole distortion and reduce etch profile deformation.

[0008] The following are some examples of methods that have been used to adjust the characteristics of the passivation layer during HAR etching, and the resulting consequences are naturally 1) increased complexity of the gas / chemical delivery device to the processing chamber; 2) poor uniformity of the passivation layer at the top and bottom of the HAR feature; 3) chamber cleaning problems - some metal-containing polymers deposit on the chamber walls, which are difficult to completely remove, etc.

[0009] Sandhu et al.'s US 20070049018 discloses a method for HAR contact etching of substantially vertical contact holes in an oxide layer using a hard photoresist mask. The plasma etching gas is a hydrocarbon fluoride comprising one of the following: CH2F2, C4F8; C3H3F5, C4F8; CHF3; C2F6; C2HF5, CH3F; or combinations thereof. The dopant molecules comprise one of HI, CH3I, carbon, potassium, calcium, PF6, BF3, chloride, AsF6, or combinations thereof. The doped plasma etching gas etches substantially vertical contact holes through the oxide layer by doping a carbon chain polymer formed along the sidewalls of the contact hole during the etching process into a conductive state. This conductive state of the carbon chain polymer reduces charge buildup along the sidewalls, preventing distortion of the contact hole, by removing charge and ensuring proper alignment with the effective area of ​​the landing zone. Etching stops at the underlying substrate.

[0010] Bera et al.'s US 7846846B2 discloses a method for etching HAR contact openings while preventing bending or folding of the etched profile by forming a highly conductive thin film on the sidewalls of each contact opening. The conductivity of the thin film on the sidewalls is increased by periodically bombarding with ions during the etching process. The etchant is a fluorocarbon / fluorocarbon gas containing at least one of the following: C2F4, C4F6, CH2F2, or C4F8; C1 to C5 saturated or unsaturated straight-chain, branched, cyclic hydrofluorocarbons, such as C4H2F6, CHF3, CH2F2, or combinations thereof.

[0011] US 9543158 by Nikhil et al. discloses various methods, apparatus, and systems for forming recessed features in dielectric materials on substrates. In some cases, plasma-assisted atomic layer deposition, modified plasma-assisted atomic layer deposition, or plasma-assisted chemical vapor deposition are used to deposit a protective coating. The etching chemistry is a combination of fluorocarbons and oxygen, C4F6, C4F3, N2, CO, CF4, and O2. The protective layer is a ceramic material or an organic polymer. For boron-containing materials, such as boron oxide (BxOy) and boron nitride (BxNy), reactants include, but are not limited to, triisopropyl borate ([(CH3)2CHO]3B), trimethylboron-d9 (B(CD3)3), etc. For silicon-containing materials, such as silicon oxide (Si... x O y ) and silicon nitride (Si x N y The reactants can be, for example, silanes, halosilanes, or aminosilanes.

[0012] HAR etching has become a critical process for memory devices. Progress has been made in controlling the ion energy of HAR features by increasing effective bias power. Significant efforts have been made to increase ion energy to overcome charge buildup at the etching front within the HAR vias. Based on bias power trends over the past few years, the required power now exceeds 20 kW. As bias power increases, many challenges arise. Preventing arcing and effective cooling, as well as the power delivery system, are all critical for achieving high power capacity. Furthermore, compensating for neutral flux becomes more difficult as aspect ratios increase, since neutral material is only transferred through diffusion through the vias.

[0013] Therefore, it is necessary to obtain a highly conductive sidewall passivation layer with reduced bias power. Summary of the Invention

[0014] A method for forming a HAR structure in a substrate during a high aspect ratio (HAR) etching process in a reaction chamber is disclosed, the method comprising: The substrate is sequentially or simultaneously exposed to vapors of etchant and additive compounds, including hydrofluorocarbons or fluorocarbons, the substrate having a film disposed thereon and a patterned mask layer disposed on the film; Activating plasma to generate activated hydrofluorocarbons or fluorocarbons and activated additive compounds; and An etching reaction is permitted between the film not covered by the patterned mask layer and the activated hydrofluorocarbon or fluorocarbon compound and the activated additive compound to selectively etch the film from the patterned mask layer, thereby forming a HAR patterned structure. The disclosed method may include one or more of the following aspects: The method further includes the step of introducing an oxidant into the reaction chamber, wherein the oxidant is selected from O2, O3, CO, CO2, NO, N2O, NO2, H2O, H2O2, COS, SO2, and combinations thereof; The oxidizing agent is O2; The oxidizing agent is O3; The oxidizing agent is CO; Etching compounds, additives, and oxygen-containing gases are mixed to produce a mixture before being introduced into the chamber; Etching compounds and additives are introduced separately from oxygen-containing gases; Oxygen-containing gas is continuously introduced, along with an iodine-containing etching compound; Oxygen-containing gas accounts for approximately 0.01% v / v to approximately 99.9% v / v of the total volume of etching compound, additives, and oxygen-containing gas; Oxygen-containing gas accounts for approximately 0.01% v / v to approximately 10% v / v of the total volume of etching compound, additives, and oxygen-containing gas; The process includes the step of introducing an inert gas into the reaction chamber, wherein the inert gas is selected from the group consisting of He, Ar, Xe, Kr, Ne and N2; The inert gas is Ar; The inert gas is Xe; The inert gas is Kr; Etching compounds, additives, and inert gases are mixed to produce a mixture before being introduced into the chamber; Etching compounds and additives are introduced separately from inert gases; Inert gas is continuously introduced and etching compounds and additives are introduced in pulses; Inert gases comprise approximately 0.01% v / v to approximately 99.9% v / v of the total volume of the etching compounds, additives, and inert gas vapors; Inert gases comprise approximately 90% v / v to approximately 99% v / v of the total volume of the etching compounds, additives, and inert gas vapors; The substrate is a Si wafer; The substrate is a crystalline silicon layer; Forming a patterned structure; The patterned structure is a 3D NAND hole; The patterned structure is a contact hole; The patterned structure is a 3D NAND contact hole; The patterned structure is a DRAM contact; The patterned structure is a channel or hole; The patterned structure is a 3D NAND channel hole; The patterned structure is a 3D NAND slot junction; The hole is a stepped contact; The hole is a self-aligning contact; The hole is a self-aligning through hole; The hole is a super-through hole; Plasma-activated fluorocarbons and activated additive compounds react with the membrane to form volatile byproducts; Remove these volatile byproducts from the reaction chamber; A highly conductive sidewall passivation layer is formed on the sidewall of the HAR patterned structure; The conductivity of a highly conductive sidewall passivation layer formed with activated hydrofluorocarbons or fluorocarbons and activated additive compounds is at least about 10% higher than that of a highly conductive sidewall passivation layer formed with activated hydrofluorocarbons or fluorocarbons without the addition of activated additive compounds. Hydrofluorocarbons or fluorocarbons include CF4, CH3F, C2F6, C3F8, C2HF5, C5F8, C6F6, C4F6, C4F8, C1 to C5 saturated or unsaturated straight-chain, branched, cyclic hydrofluorocarbons such as C4H2F6, CHF3, CH2F2, or combinations thereof; Hydrofluorocarbons or fluorocarbons are C4H2F6; The additive compound contains silicon, carbon, and / or iodine, and has the following formula: C n R 1 R 2 R 3 I, SiR 1 R 2 R 3 I, SiR 1 R 2 I x F (2-x) , SiRI y F (3-y) , SiI z F (4-z) ,or C n F (2n+1) I Where n = 1 to 10; x = 1-2; y = 1-3; z = 1-3; R, R 1 R 2 and R 3 Each is independently selected from H, C1-C 10 Straight-chain, branched, or cyclic; saturated or unsaturated; aromatic, heterocyclic, partially or fully fluorinated, substituted or unsubstituted hydrocarbon groups; R 1 and R 2 R 2 and R 3 、or R 1 and R 3 They can also be linked to form cyclic groups; Additive compounds are selected from or ; The above-disclosed additive CR 1 R 2 R 3 I include and .

[0015] The additive SiR disclosed above 1 R 2 R 3 I include

[0016] · and .

[0017] The additive SiR disclosed above 1 R 2 I x F (2-x) include and .

[0018] The additive SiRI disclosed above y F (3-y) include and .

[0019] The additive SiI disclosed above z F (4-z) include and ; Disclosed Additive C n F (2n+1) I include ; Additive compounds are selected from Iodomethacin CH3I (CAS No.: 74-88-4). Iodobenzene C6H5I (CAS No.: 591-50-4). 2-Iodopropane C3H7I (CAS No.: 75-30-9). 1-Iodopropane C3H7I (CAS No.: 107-08-4). 1-Iodoethane C2H5I (CAS No.: 75-03-6). Perfluoroiodobutane C4H9I (CAS No.: 423-39-2). difluoroiodomethane CHIF2 (CAS No.: 1493-03-4). Difluoroiodo(pentafluoroethyl)-silane C2F7ISi (CAS No.: 36972-59-5). 1-(Difluoroiodosilyl)-2-methylbenzene C7H7F2ISi (CAS No.: 174711-76-3). Difluoroiodo(trifluoromethyl)-silane CF5ISi (CAS No.: 27668-68-4). Triethyliodosilane C6H 15 ISi (CAS No.: 1112-49-8), Fluorotriiodosilane FI3Si (CAS No.: 16865-60-4). Difluorodiiodosilane F2I2Si (CAS No.: 27669-15-4). Trifluoroiodosilane F3ISi (CAS No.: 27668-68-4). Iodotrimethylsilane C3H9ISi (CAS No.: 16029-98-4), or Diiodosilane SiH2I2 (CAS No.: 13760-02-6); The additive compound is iodo-methane CH3I (CAS No.: 74-88-4). The additive compound is iodo-benzene C6H5I (CAS No.: 591-50-4). The additive compound is 2-iodopropane C3H7I (CAS No.: 75-30-9). The additive compound is 1-iodopropane C3H7I (CAS No.: 107-08-4). The additive compound is 1-iodoethane C2H5I (CAS No.: 75-03-6). The additive compound is perfluoroiodobutane C4F9I (CAS No.: 423-39-2). The additive compound is difluoroiodomethane CHIF2 (CAS No.: 1493-03-4). The additive compound is difluoroiodo(pentafluoroethyl)-silane C2F7ISi (CAS No.: 36972-59-5). The additive compound is difluoroiodo(pentafluoroethyl)-silane C2F7ISi (CAS No.: 36972-59-5). The additive compound is 1-(difluoroiodosilyl)-2-methylbenzene C7H7F2ISi (CAS No.: 174711-76-3). The additive compound is difluoroiodo(trifluoromethyl)-silane CF5ISi (CAS No.: 27668-68-4). The additive compound is triethyliodosilane (C6H). 15 ISi (CAS No.: 1112-49-8); The additive compound is fluorotriiodosilane FI3Si (CAS No.: 16865-60-4). The additive compound is difluorodiiodosilane F2I2Si (CAS No.: 27669-15-4). The additive compound is trifluoroiodosilane F3ISi (CAS No.: 27668-68-4). The additive compound is triiodotrimethylsilane C3H9ISi (CAS No.: 16029-98-4). The additive compound is diiodosilane SiH2I2 (CAS No.: 13760-02-6). The film is a silicon-containing film containing O and / or N and optionally containing dopants such as B, C, P, As, Ga, In, Sn, Sb, Bi and / or Ge, and combinations thereof; The membrane is a silicon-containing membrane containing oxygen; The membrane is a silicon-containing membrane containing nitrogen (N). The film is a silicon-containing film, which optionally contains dopants such as B, C, P, As, Ga, In, Sn, Sb, Bi and / or Ge, and combinations thereof; Silicon-containing films comprise layers of the following: silicon oxide (SiO), silicon nitride (SiN), crystalline Si, p-silicon, polycrystalline silicon, amorphous silicon, and low-silicon oxide. k 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 SiO and SiN (ONON) layers; alternating SiO and p-Si (OPOP) layers; Silicon-containing films contain oxygen, nitrogen, carbon, hydrogen, or combinations thereof; The silicon-containing film is SiO x N y H z C k , where x is in the range from 0 to 2, y is in the range from 0 to 4, z is in the range from 0 to about 1 and k is in the range from 0 to 1; The silicon-containing film includes 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 SiO and p-Si (OPOP) layers; The silicon-containing film contains dopants such as B, C, P, As, Ga, In, Sn, Sb, Bi and / or Ge; Alternating layers comprise layers of the following: silicon oxide, silicon nitride, polycrystalline silicon, crystalline silicon, SiOCH, SiON, and Si. a O b C c N d H e (where a > 0; b, c, d, and e ≥ 0) or combinations thereof; The alternating layers contain oxygen atoms, nitrogen atoms, carbon atoms, hydrogen atoms, or combinations thereof; The alternating layers are silicon-containing films; The alternating layers consist of a silicon oxide layer and a silicon nitride layer; The alternating layers consist of alternating layers of silicon oxide and silicon nitride; The alternating layers are alternating layers of silicon oxide and silicon nitride; The alternating layers consist of a silicon oxide layer and a polysilicon layer; The alternating layers consist of alternating layers of silicon oxide and polycrystalline silicon; The alternating layers are alternating layers of silicon oxide and polycrystalline silicon; 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 polycrystalline silicon layer is selectively etched from the doped carbon layer; The silicon-containing film is selectively etched from the following: amorphous carbon layer, doped amorphous carbon layer, photoresist layer, antireflection layer or organic planarization layer; The silicon oxide layer is selectively etched from the following: amorphous carbon layer, doped amorphous carbon layer, photoresist layer, antireflection layer or organic planarization layer; The etching compound etches both the silicon oxide layer and the silicon nitride layer at a high etching rate; The patterned mask layer is an aC layer, a doped aC layer, a photoresist layer, an antireflection layer, an organic planarization layer, a polysilicon layer, a metal oxide layer such as oxides of Ti, Al, Zr, Hf, etc., and combinations thereof. The hard mask layer is placed on 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 antireflection layer, an organic planarization layer, or a combination thereof; Hard mask layers are layers of the following: CVD, PECVD, ALD, PEALD or spin-on deposition (SOD) amorphous carbon or doped amorphous carbon, silicon spin-on mask, or carbon spin-on mask. The hard mask layer is an amorphous carbon (aC) layer; The hard mask layer is a doped carbon layer; The doped amorphous carbon layer is a boron-doped aC layer; The doped amorphous carbon layer is a tungsten-doped aC layer; The HAR patterned structures formed in the membrane have an aspect ratio between approximately 1:1 and approximately 200:1; The HAR patterned structures formed in the membrane have aspect ratios between approximately 1:1 and approximately 20:1; The HAR patterned structures formed in the membrane have aspect ratios between approximately 21:1 and approximately 60:1; The HAR patterned structures formed in the membrane have an aspect ratio between approximately 21:1 and approximately 200:1; The HAR patterned structures formed in the membrane have an aspect ratio between approximately 61:1 and approximately 200:1; Further, it includes introducing an additional etching gas into the reaction chamber, wherein the additional etching gas is selected from the group consisting of: 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), hexafluoroisobutylene (C4H2F6), trans-1,1,2,2,3,4-hexafluorocyclobutane (C4H2F6) trans -C4H2F6), 1,1,2,2,3-pentafluorocyclobutane (C4H3F5), 1,1,2,2-tetrafluorocyclobutane (C4H4F4), and cis-1,1,2,2,3,4-hexa ...6), 1,1,2,2,3,4-hexafluorocyclobutane (C4H3F5), 1,1,2,2-tetrafluorocyclobutane (C4H4F4), and cis-1,1,2,2,3,4-hexafluorocyclobutane (C4H3F5), 1,1,2,2-te Cis -C4H2F6) and its combinations; Etching compounds and additives are introduced separately from additional etching gases; Additional etching gas of approximately 0.01% v / v to approximately 99.99% v / v is added to the etching compound and additives; Plasma is activated by applying RF power; The plasma was activated by RF power ranging from approximately 25 W to approximately 100,000 W. Compared to etching without additives, the bias power is low by using additives with hydrofluorocarbons or fluorocarbons. By using additives with hydrofluorocarbons or fluorocarbons, the bias power is at least about 10% lower than that without the use of additives; The etching pressure ranges from approximately 1 millitor to approximately 100 tors; The etching pressure ranges from approximately 1 millitor to approximately 50 tors; The etching pressure ranges from approximately 1 millitor to approximately 10 tors. The etching pressure ranges from approximately 1 mTorr to approximately 50 mTorr; Etching compound and additive vapors are introduced at flow rates ranging from approximately 0.1 sccm to approximately 1 slm. Etching compound vapor is introduced at a flow rate ranging from approximately 0.1 sccm to approximately 1 slm; The vapor of the additive is introduced at a flow rate ranging from about 0.1 sccm to about 1 slm; The substrate is maintained at a temperature ranging from approximately -100°C to approximately 500°C; The substrate is maintained at a temperature ranging from approximately 20°C to approximately 150°C; The substrate is maintained at a temperature ranging from approximately 20°C to approximately 110°C; and Etched compounds are measured in plasma using a quadrupole mass spectrometer, optical emission spectrometer, FTIR, or other free radical / ion measurement tools.

[0020] A method for forming HAR patterned structures is also disclosed, which includes the following steps: A substrate is sequentially or simultaneously exposed to vapors of C4H2F6 and CH3I, the substrate having a film disposed thereon and a patterned mask layer disposed on the film; Activating plasma to produce activated C4H2F6 and activated CH3I; and An etching reaction is permitted between the film not covered by the patterned mask layer and the activated C4H2F6 and CH3I to selectively etch the film from the patterned mask layer, thereby forming the HAR patterned structure. The disclosed method may include one or more of the following aspects: The method further includes the step of introducing an oxidant into the reaction chamber, wherein the oxidant is selected from O2, O3, CO, CO2, NO, N2O, NO2, H2O, H2O2, COS, SO2, and combinations thereof; The process further includes the step of introducing an inert gas into the reaction chamber, wherein the inert gas is selected from the group consisting of He, Ar, Xe, Kr, Ne and N2; A highly conductive sidewall passivation layer is formed on the sidewall of the HAR patterned structure; The conductivity of the highly conductive sidewall passivation layer formed with activated C4H2F6 and activated CH3I is at least about 10% higher than that of the highly conductive sidewall passivation layer formed with activated C4H2F6 without the addition of activated CH3I. The HAR patterned structures formed in the membrane have an aspect ratio between approximately 1:1 and approximately 200:1; Further, it includes introducing an additional etching gas into the reaction chamber, wherein the additional etching gas is selected from the group consisting of: 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), hexafluoroisobutylene (C4H2F6), trans-1,1,2,2,3,4-hexafluorocyclobutane (C4H2F6) trans -C4H2F6), 1,1,2,2,3-pentafluorocyclobutane (C4H3F5), 1,1,2,2-tetrafluorocyclobutane (C4H4F4), and cis-1,1,2,2,3,4-hexa ...6), 1,1,2,2,3,4-hexafluorocyclobutane (C4H3F5), 1,1,2,2-tetrafluorocyclobutane (C4H4F4), and cis-1,1,2,2,3,4-hexafluorocyclobutane (C4H3F5), 1,1,2,2-te Cis -C4H2F6) and its combinations; and The film is a silicon-containing film containing O and / or N and optionally containing dopants such as B, C, P, As, Ga, In, Sn, Sb, Bi and / or Ge, and combinations thereof.

[0021] Symbols and nomenclature

[0022] The following detailed description and claims utilize many abbreviations, symbols, and terms commonly known in the art, and include: As used in this article, the indefinite article “a or an” means one or more species.

[0023] As used herein, “about” or “around or approximately” in the text or claims means ± 10% of the value.

[0024] As used herein, “room temperature” in the text or claims means from about 20°C to about 25°C.

[0025] The term “wafer” or “patterned wafer” refers to a wafer having a stack of any existing films (including silicon-containing films) on a substrate and having a patterned hard mask layer on the stack of any existing films (including silicon-containing films) for patterning etching.

[0026] The term "substrate" refers to one or more materials on which processes are performed. A substrate can be a wafer or a patterned wafer having one or more materials on which etching processes are performed. A substrate can be any suitable wafer used in the manufacture of semiconductor, photovoltaic, flat panel, or LCD-TFT devices. A substrate can also have one or more different material layers deposited thereon from previous manufacturing steps. For example, a wafer can include silicon layers (e.g., crystalline, amorphous, porous, etc.), silicon-containing layers (e.g., SiO2, SiN, SiON, SiCOH, etc.), metal-containing layers (e.g., copper, cobalt, ruthenium, tungsten, indium, platinum, palladium, nickel, ruthenium, gold, etc.), or combinations thereof. Furthermore, a substrate can be planar or patterned. A substrate can be an organically patterned photoresist film. The substrate may include oxide layers (e.g., ZrO2-based materials, HfO2-based materials, TiO2-based materials, rare earth oxide-based materials, ternary oxide-based materials, etc.) used as dielectric materials in MEMS, 3D NAND, MIM, DRAM, or FeRam device applications; nitride-based films (e.g., TaN, TiN, NbN) used as electrodes; or metal-containing or metal alloy-based films (e.g., InGaAs, In...) used as stronger competitors to silicon in future CMOS systems. x O y (x = 0.5 to 1.5, y = 0.5 to 1.5), InSnO (ITO), InGaZnO (IGZO), InN, InP, InAs, InSb, In2S3, or In(OH)3, etc.). Those skilled in the art will recognize that the terms "film" or "layer" as used herein refer to a material of a certain thickness placed or spread on a surface, and that surface may be trenches or lines. Throughout the specification and claims, the wafer and any associated layers thereon are referred to as a substrate.

[0027] The term “patterned etching” or “patterned etching” refers to etching non-planar structures, such as stacks of silicon-containing films beneath patterned hard mask layers.

[0028] As used herein, the term "etch" refers to the removal of material using etching compounds and / or plasma via ion bombardment, remote plasma, or a chemical vapor phase reaction between an etching gas and a substrate, and refers 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 from the substrate. This type of etching process includes chemical dry etching, vapor phase chemical etching, thermal dry etching, etc. Isotropic etching processes create lateral or horizontal etch profiles in the substrate. Isotropic etching processes create grooves or horizontal recesses on the sidewalls of pre-formed holes in the substrate. Anisotropic etching processes involve plasma etching processes (i.e., dry etching processes), where ion bombardment accelerates a chemical reaction in the vertical direction, resulting in the formation of vertical sidewalls perpendicular to the substrate along the edges of the masking feature (Manos and Flamm, Thermal Etching an Introduction, Academic Press, Inc., 1989, pp. 12-13). Plasma etching creates vertical etched profiles in a substrate. It can also create vertical vias, holes, trenches, channel holes, gate trenches, stepped contacts, capacitor holes, contact holes, slot etching, self-aligned contacts, self-aligned vias, and supervias.

[0029] The term "mask" refers to a layer that resists etching. This mask layer can be located above the layer to be etched. It also refers to a hard mask layer. The mask layer can be an amorphous carbon (aC) layer, a doped aC layer, a photoresist layer, an antireflective layer, an organic planarization layer, or a combination thereof. The mask layer can also be a silicon layer such as polysilicon, metal oxides such as oxides of Ti, Al, Zr, Hf, etc., or a combination thereof.

[0030] The term "aspect ratio" refers to the ratio of the height of a groove (or hole) to the width of the groove (or the diameter of the hole).

[0031] The term "etch stop" refers to a layer that protects the underlying layer below the layer being etched.

[0032] The term "device channel" refers to a layer that is part of the actual device, and any damage to it will affect device performance.

[0033] The term "selectivity" refers to the ratio of the etching rate of one material to the etching rate of another material. The terms "selective etch" or "selectively etch" mean etching one material more than another, or in other words, having an etching selectivity greater than or less than 1:1 between the two materials.

[0034] The terms “via,” “aperture,” “trench,” and “hole” are sometimes used interchangeably and generally refer to an opening in an interlayer insulator.

[0035] The terms "low bias power" or "reduced bias power" refer to a bias power lower than that of the baseline process.

[0036] As used in this article, the term "additive" refers to a compound or gas that is added to other etching compounds and provides improved etching properties such as improved profile properties, such as bend, CD, ellipticity, etc.

[0037] The term "ellipticity" used in this article refers to a method for measuring mask degradation, where, for simplicity in etching applications, it is expressed as (short hole width / long hole width). The ellipticity of the etched hole is estimated to be 100%; therefore, the ellipticity of a perfectly circular hole is defined as 100%.

[0038] As used herein, the abbreviation “NAND” refers to a “Negated AND” or “Not AND” gate; the abbreviation “2D” refers to a 2D gate structure on a planar substrate; and the abbreviation “3D” refers to a 3D or vertical gate structure in which the gate structures are stacked in the vertical direction.

[0039] As used in this paper, the term "mercury probe" refers to an electrical probe device that makes rapid, non-destructive contact with a sample for electrical characterization. If the mercury sample contact is measured in ohms (non-rectified), then a current-voltage meter can be used to measure resistance, leakage current, or current-voltage characteristics. Resistance can be measured on bulk samples or thin films. Thin films can be made of any material that does not react with mercury. The mercury probe used in this paper has a mercury contact diameter of 760 μm.

[0040] The term "conductivity" used in this article is the reciprocal of resistivity and represents a material's ability to conduct electric current. The unit of conductivity used in this article is Siemens per centimeter (S / cm). It is measured using a mercury probe and... The solution is calculated from the current-voltage curve under an electric field of 0.2 MV / cm, where... Here, I is the electrical conductivity, T is the current measured by the mercury probe, A is the polymer thickness, and A is the contact area of ​​the mercury probe. The electric field is defined as the applied voltage divided by the polymer thickness. For example, in... Figure 10 In the experiment, when the electric field is 0.2 MV / cm, the measured current is 1.92 × 10⁻⁶. -11 The calculated conductivity of the C4F8 polymer is 2.14 × 10⁻⁶. -9 S / cm.

[0041] The term "highly conductive sidewall passivation layer" as used in this article refers to a conductivity higher than that of the C4F8 polymer (calculated as 2.14 × 10⁻⁶). -9 The electrical conductivity of the sidewall passivation layer (S / cm).

[0042] It should be noted in this document that the terms “film” and “layer” are used interchangeably. It should be understood that a film can correspond to or be associated with a layer, and a layer can refer to a film. Furthermore, those skilled in the art will recognize that, as used herein, the terms “film” or “layer” refer to a material of a certain thickness placed or spread on a surface, and that surface can range from as large as an entire wafer to as small as a trench or line.

[0043] It should be noted in this document that the terms “etching compound,” “etching agent,” “etching gas,” and “process gas” are used interchangeably when the etching compound is in a gaseous state at room temperature and ambient pressure. It should be understood that an etching compound may correspond to, or be associated with, an etching gas, an etching agent, or a process gas, and that an etching gas, etching agent, or process gas may refer to an etching compound.

[0044] This article uses standard abbreviations of elements from the periodic table. It should be understood that elements may be referred to by these abbreviations (e.g., Si for silicon, N for nitrogen, O for oxygen, C for carbon, H for hydrogen, F for fluorine, etc.).

[0045] A unique CAS registry number (i.e., "CAS") assigned by the Chemical Abstracts Service is provided to identify the specific molecule disclosed.

[0046] Please note that silicon-containing films, such as SiN and SiO, are listed throughout this specification and claims without mentioning their appropriate stoichiometry. Silicon-containing films may include pure silicon (Si) layers, such as crystalline Si, polycrystalline silicon (p-Si or polycrystalline Si), or amorphous silicon; silicon nitride (SiO2)... k N l ) layer; or silicon dioxide (Si) n O mA layer; or a mixture thereof, wherein k, I, m, and n range from 0.1 to 6 (inclusive of the endpoints). Preferably, silicon nitride is Si. k N l Where k and I each range from 0.5 to 1.5. More preferably, silicon nitride is Si3N4. In this document, SiN as described below can be used to represent Si-containing silicon. k N l The layer. Preferably, the silicon oxide is Si. n O m Where n ranges from 0.5 to 1.5 and m ranges from 1.5 to 3.5. More preferably, the silicon oxide is SiO2. In this document, SiO as described below can be used to represent Si-containing... n O m The silicon-containing film may also be a silicon oxide-based dielectric material, such as an organic-based or silicon oxide-based low-... k Dielectric materials, such as Applied Materials, Inc.'s BlackDiamond II or III materials (with the formula SiOCH). Silicon-containing films may also include Si. a O b N c Where a, b, and c range from 0.1 to 6. The silicon-containing film may also include dopants such as B, C, P, As, Ga, In, Sn, Sb, Bi, and / or Ge, and combinations thereof.

[0047] When used in the context of describing an R group, the term "independently" should be understood to mean that the object R group is chosen independently not only relative to other R groups with the same or different subscripts or superscripts, but also independently relative to any additional kind of the same R group. For example, in the formula MR 1 x (NR 2 R 3 ) (4-x) In the context, M represents an atom, x is 2 or 3, and there are two or three R atoms. 1 Groups can, but do not have to, be the same as each other or with R. 2 Or with R 3 The same applies. Furthermore, it should be understood that, unless otherwise specified, the values ​​of the R group are independent of each other when used in different formulas.

[0048] In this document, a range may be expressed as from about one specific value and / or to about another specific value. When such a range is expressed, it should be understood that another embodiment is from one specific value and / or to another specific value, together with all combinations within the range.

[0049] In this document, references to "an embodiment" or "embodiment" mean that a particular feature, structure, or characteristic described with respect to that embodiment may be included in at least one embodiment of the invention. The phrase "in an embodiment" appearing in different places in the specification does not necessarily refer to the same embodiment in all instances, and individual or alternative embodiments are not necessarily mutually exclusive with other embodiments. The foregoing also applies to the term "implementation". Attached Figure Description

[0050] To further understand the nature and purpose of the present invention, reference should be made to the following detailed description in conjunction with the accompanying drawings, in which similar elements are given the same or similar reference numerals, and in the drawings: Figure 1 The conductivity of C4H2F6 with and without the additive CH3I was measured on a planar wafer. Figure 2 The conductivity of C4H2F6 with and without the additive C4F9I was measured on a planar wafer. Figure 3 The conductivity of C4H2F6 with and without the additive SiH2I2 was measured on a planar wafer. Figure 4 This is a comparison of the ER and selectivity of C4H2F6 with and without CH3I additive; Figure 5 It is a comparison of the sidewall bending of C4H2F6 with and without CH3I additive; Figure 6 It is a comparison of the ellipticity of C4H2F6 with and without CH3I additive; Figure 7 It is a comparison of the critical size (CD) of C4H2F6 with and without CH3I additive at a bias power of 7000 W; Figure 8 This is a comparison of CD with and without CH3I additive for C4H2F6 at a bias power of 5600 W; Figure 9 This is a comparison of CD (cathode) of C4H2F6 with and without CH3I additive at a bias power of 4200 W; and Figure 10 It refers to the chemical composition and electrical conductivity of various polymers. Detailed Implementation

[0051] A method is disclosed for forming a highly conductive sidewall passivation layer on the sidewalls by doping with Si, C, and / or iodine in a high aspect ratio (HAR) plasma etching process using an etching gas as an additive. The disclosed method forms the highly conductive sidewall passivation layer in the HAR plasma etching process using additives or additive chemicals by doping with Si, C, and / or iodine. This highly conductive sidewall passivation layer can be a polymer passivation layer. The conductive state of this polymer passivation layer reduces charge accumulation along the sidewalls by removing charge and ensuring proper control of the critical size (CD) change at low bias power levels or even no bias power, thus preventing distortion of HAR structures such as holes. By applying the additive, the bias power can be at least about 10% lower than without the additive, or even no bias power is required.

[0052] The disclosed method can also be considered as low-bias-energy plasma etching, because with minimized sidewall charge, reactive ions require less plasma bias power to reach the bottom of the HAR trench. Furthermore, the disclosed etching or processing gases, including additives, do not contain any elements that are difficult to clean, which also minimizes contamination of the reaction chamber and reduces tooling maintenance / downtime.

[0053] The disclosed method involves plasma etching a patterned wafer or substrate using a hydrofluorocarbon etchant gas and an additive gas at a reduced bias power for a predetermined time. This predetermined time can be in the range of 0 s to 1000 s to stabilize the pressure and gas flow rate in the chamber before activating the plasma.

[0054] The disclosed additives or additive chemicals contain Si, C and / or iodine elements and have the following formula: CR 1 R 2 R 3 I, SiR 1 R 2 R 3 I, SiR 1 R 2 I x F (2-x) , SiRI y F (3-y) , SiI z F (4-z) ,or C n F (2n+1) I Where x = 1-2; y = 1-3; z = 1-4; R, R 1 R 2and R 3 Each is independently selected from H, D (deuterium), C1-C 10 Straight-chain, branched, or cyclic; saturated or unsaturated; aromatic, heterocyclic, partially or fully fluorinated, substituted or unsubstituted hydrocarbon groups. R 1 and R 2 R 2 and R 3 、or R 1 and R 3 They can also be linked to form cyclic groups.

[0055] The above-disclosed additive CR 1 R 2 R 3 I can include and .

[0056] The additive SiR disclosed above 1 R 2 R 3 I can include

[0057] . and .

[0058] The additive SiR disclosed above 1 R 2 I x F (2-x) It can include and .

[0059] The additive SiRI disclosed above y F (3-y) It can include and .

[0060] The additive SiI disclosed above z F (4-z) It can include and .

[0061] Disclosed Additive C n F(2n+1) I include .

[0062] Exemplary additives containing Si, C, and / or iodine are listed in Table 1. 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 the table. The disclosed additives containing Si, C, and / or iodine may also include their isomers.

[0063] Table 1.

[0064] Since high volatility is preferred for etching gases, it is also desirable for additive chemicals. As mentioned above, for additives, small hydrocarbon groups are used as substituents on silicon, which provides additives with high volatility. Another advantage provided by using hydrocarbon substituents is the increased possibility of incorporating carbon into the passivation of sidewalls due to the generation of poor carbon leaving groups. The use of aromatic substituents on silicon is also recommended in novel molecules because including aromatic groups in the passivation of sidewalls can produce increased conductivity. Substitution on aromatic groups is also of interest because the electronics of aromatic rings can alter conductivity. However, those skilled in the art will understand that low-volatility etching materials can also be used. Low-volatility etching materials can be used by various methods, such as heating the source of the low-volatility etching material to increase volatility, including heating the container or cylinder containing the low-volatility etching material and the gas line connected to the etching tool, using a bubbler method in which an inert gas is bubbled through the liquid low-volatility etching material, etc.

[0065] The disclosed additives are suitable for designing passivation layer characteristics formed on the sidewalls of high aspect ratio holes / trenches. Sidewall passivation and down-etching occur simultaneously. The passivation layer can originate from a carbon source in the plasma etching gas, from the reaction between the etching gas and the exposed material, or from the redeposition of byproducts of the etching process. The etchant additives strongly influence the chemical composition of the sidewall passivation by introducing conductive elements and / or chemical bonds, thereby positively affecting the conductivity of the sidewall passivation. During plasma etching, the bottom of the structure may be positively charged while the sidewalls are negatively charged, thus establishing an undesirable local electric field within the structure. Only high-energy ions with energies greater than the potential difference along this local electric field can reach the bottom. As the conductivity of the sidewall passivation increases, the charge on the sidewalls dissipates rapidly. The required bias power is lower than that of the baseline process.

[0066] The disclosed etching gas may be a fluorocarbon / hydrofluorocarbon. Exemplary disclosed fluorocarbons / hydrofluorocarbons include CF4, CH3F, C2F6, C3F8, C2HF5, C5F8, C6F6, C4F6, C4F8, C1 to C5 saturated or unsaturated straight-chain, branched, cyclic hydrofluorocarbons such as C4H2F6, CHF3, CH2F2, or combinations thereof.

[0067] The disclosed fluorocarbons / hydrofluorocarbons are suitable for etching silicon-containing films, which include layers of the following: silicon oxide (SiO), silicon nitride (SiN), pure silicon (Si) such as crystalline Si, polycrystalline silicon (p-Si or polycrystalline Si), amorphous silicon, low-k SiCOH, SiOCN, SiC, SiON, and Si. a O b H c C d N e Where a > 0; b, c, d, and e ≥ 0; and containing metal films (e.g., copper, cobalt, ruthenium, tungsten, indium, platinum, palladium, nickel, ruthenium, gold, etc.). Silicon-containing films may also include alternating SiO and SiN (ONON) layers or SiO and p-Si (OPOP) layers. Silicon-containing films contain O and / or N. Silicon-containing films may also include dopants such as B, C, P, As, Ga, In, Sn, Sb, Bi, and / or Ge, and combinations thereof.

[0068] The disclosed fluorocarbons / hydrofluorocarbons and additives 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 fluorocarbons / hydrofluorocarbons and additives contain less than 5% by volume of trace gaseous impurities, wherein less than 150 ppm by volume of impurity gases, such as N2 and / or H2O and / or CO2, are included in the trace gaseous impurities. Preferably, the water content in the plasma etching gas is less than 20 ppm by weight. The purified product can be produced by distillation and / or by passing the gas or liquid through a suitable adsorbent (such as a 4Å molecular sieve).

[0069] The disclosed fluorocarbons / hydrofluorocarbons and additives 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 their isomers, which can be purified by distilling gases or liquids to remove the isomers and can provide better process repeatability.

[0070] The disclosed fluorocarbon / hydrofluorocarbon selectively etches a silicon-containing layer from a buried landing layer or material, which in most applications is a metal layer located at the bottom of the structure to be etched. The disclosed fluorocarbon / hydrofluorocarbon does not etch the metal landing layer. The buried landing layer can be an etching stop layer or a diffusion barrier layer. The material of the metal landing layer can be a tungsten metal processing line in 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 combinations 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 combinations thereof).

[0071] The disclosed fluorocarbons / hydrofluorocarbons can be used for plasma etching of silicon-containing films on substrates. The disclosed plasma etching method can be used to fabricate semiconductor devices, such as NAND or 3D NAND gates, flash or DRAM memories, or transistors, such as fin field-effect transistors (FinFETs), gate-all-around (GAA) FETs, nanowire FETs, nanosheet FETs, forked 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 used in other application areas, such as various front-end online (FEOL) and back-end online (BEOL) etching applications. Furthermore, the disclosed iodine-containing etching compounds can also be used to etch Si in 3D through-silicon via (TSV) etching applications to interconnect memory with logic circuitry on substrates and in MEMS applications.

[0072] The disclosed etching method includes providing a reaction chamber with a substrate disposed therein. The reaction chamber can be any accessory or chamber within an apparatus in which the etching method is performed, such as, and not limited to, reactive ion etching (RIE), CCP with a single or multiple frequency RF sources, inductively coupled plasma (ICP), or a microwave plasma reactor, or other types of etching systems capable of selectively removing a portion of a silicon-containing film or generating active material. 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, those branded eMAX. TM Selling Applied Materials' magnetically enhanced reactive ion etchers or trademarked 2300® Flex TM The Lam Research family of dual CCP reactive ion etchers for sale, or the Advanced Micro-Fabrication Equipment Inc. (AMEC) Primo SSC HD-RIE etcher. The RF power in such a plasma reaction chamber can be pulsed to control plasma characteristics and thus further improve etching performance (selectivity and damage).

[0073] 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 substrate can be any suitable substrate used in the manufacture of semiconductor, photovoltaic, flat panel, or LCD-TFT devices. Examples of suitable substrates include wafers such as silicon, silicon dioxide, glass, Ge, SiGe, GeSn, InGaAs, GaSb, InP, or GaAs wafers. From previous manufacturing steps, the wafer will have multiple films or layers thereon, including silicon-containing films or layers. These layers may be patterned or may not be patterned. Examples of suitable layers include, but are not limited to, silicon (such as 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), silicon dioxide, silicon nitride, silicon oxide, silicon oxynitride, Si a O b H c C d N e (where a > 0; b, c, d, e ≥ 0), Ge, SiGe, GeSn, InGaAs, GaSb, InP; mask layer materials such as amorphous carbon with or without dopants, antireflective coatings, photoresist materials, metal oxides (such as AlO, TiO, HfO, ZrO, SnO, TaO, etc.) or metal nitride layers (such as AlN, ZrN, SnN, HfN, titanium nitride, tantalum nitride, etc.) or combinations thereof; etch stop layer materials (such as silicon nitride, polycrystalline silicon, 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(Where a > 0; b, c, d, e ≥ 0) or combinations thereof. aC (amorphous carbon) is a carbon film deposited using a PE-CVD process. It is primarily composed of carbon containing a certain amount of hydrogen. Doped aC is an amorphous carbon film in which a dopant is deposited during the deposition process. Dopants may include boron, zirconium, aluminum, titanium, and tungsten. Carbon films can also be deposited using a spin-coating process, compared to PE-CVD. This silicon oxide layer can form a dielectric material, such as an organic-based or silicon oxide-based low-k dielectric material (e.g., a porous SiCOH film). Exemplary low-k dielectric materials are sold by Applied Materials under the trade names BlackDiamond II or III. Alternatively, layers containing tungsten or noble metals (e.g., platinum, palladium, rhodium, or gold) can be used. Furthermore, examples of these silicon-containing films may be 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 thereon are referred to as the substrate.

[0074] The disclosed etching method involves evacuating the reaction chamber to a high vacuum after placing the substrate into the chamber and before introducing the disclosed fluorocarbon / hydrofluorocarbon into the chamber. This high vacuum can be in the range of 0.01 mTorr to 10 mTorr.

[0075] An inert gas is also introduced into the reaction chamber to sustain the plasma. This inert gas can be He, Ar, Xe, Kr, Ne, N2, He, or a combination thereof. Before introduction into the chamber, the etching gas and the inert gas can be mixed, wherein the inert gas constitutes between approximately 0.01% v / v and approximately 99.9% v / v of the resulting mixture. Alternatively, the inert gas can be introduced into the chamber continuously, while the etching gas can be introduced into the chamber in a pulsed manner.

[0076] The disclosed etching gas vapor and inert gas are activated by plasma to generate activated etching gas. The plasma decomposes the etching gas into free radical form (i.e., activated etching gas). The plasma can be generated by applying RF or DC power. The plasma can be generated with RF power ranging from about 25 W to about 100,000 W. The plasma can be generated remotely or within the reactor itself. The plasma can be generated under RF applied at two electrodes in dual CCP or ICP mode. The RF frequency of the plasma can range from 100 kHz to 1 GHz. Different RF sources at different frequencies can be coupled and applied at the same electrode. The plasma RF pulse can be further used to control molecular debris and reactions at the substrate. Those skilled in the art will recognize the methods and apparatus suitable for this plasma treatment.

[0077] Quadrupole mass spectrometry (QMS), optical emission spectrometry, FTIR, or other radical / ion measurement tools can measure the activated etching gas from the chamber exhaust to determine the type and number of species produced. If necessary, the flow rates of the etching gas and / or inert gas can be adjusted to increase or decrease the amount of free radicals produced.

[0078] The disclosed etching gases and additives may be mixed with other gases or co-reactants before or within the reaction chamber. Preferably, these gases may be mixed before introduction into the chamber to provide a uniform concentration of the inlet gas.

[0079] In another alternative, vapors of hydrofluorocarbon etching compounds and additives can be introduced into the chamber independently of other gases, such as when two or more gases react or are more easily delivered independently.

[0080] In another alternative, the hydrofluorocarbon etching gas and the additive gas are the only two gases used during the etching process.

[0081] In another alternative, hydrofluorocarbon etching gas, additive gas, and inert gas are the only three gases used during the etching process.

[0082] Other exemplary gases or co-reactants include, but are not limited to, oxidants such as O2, O3, CO, CO2, NO, N2O, NO2, H2O, H2O2, COS, SO2, and combinations thereof. The disclosed etching gases / additives and oxidants may be mixed together before being introduced into the reaction chamber.

[0083] Alternatively, an oxidant may be continuously introduced into the chamber, and an etching gas may be introduced into the chamber in a pulsed manner. The oxidant may constitute between approximately 0.01% v / v and approximately 99.99% v / v of the mixture introduced into the chamber (where 99.99% v / v represents the introduction of an almost pure oxidant for the continuous introduction alternative).

[0084] Other exemplary gases that can be used with the disclosed hydrofluorocarbon etching gases and additive gases include additional etching gases such as cC4F8, C4F8, cC5F8, C5F8, C4F6, CF4, CH3F, CF3H, CH2F2, C3HF7, C3F6, C3H2F6, C3H2F4, C3H3F5, C4HF7, C5HF9, C3F6, C3F8, CF3I, C2F3I, C2F5I, C3F7I, 1-iodoheptafluoropropane (1-C3F7I), 2-iodoheptafluoropropane (2-C3F7I), C3HF7, COS, FNO, FC≡N, CS2, SO2, H2S, SF6, trans-1,1,1,4,4,4-hexafluoro-2-butene (… trans -C4H2F6), cis-1,1,1,4,4,4-hexafluoro-2-butene ( Cis -C4H2F6), hexafluoroisobutylene (C4H2F6), trans-1,1,2,2,3,4-hexafluorocyclobutane (C4H2F6) trans -C4H2F6), 1,1,2,2,3-pentafluorocyclobutane (C4H3F5), 1,1,2,2-tetrafluorocyclobutane (C4H4F4), and cis-1,1,2,2,3,4-hexa ...6), 1,1,2,2,3,4-hexafluorocyclobutane (C4H3F5), 1,1,2,2-tetrafluorocyclobutane (C4H4F4), and cis-1,1,2,2,3,4-hexafluorocyclobutane (C4H3F5), 1,1,2,2-te Cis -C4H2F6) or combinations thereof. For example, the disclosed iodine-containing etch compound at approximately 1% v / v to approximately 25% v / v can be used with the balance C4F6 or cC4F8. As shown in the examples below, the combination of the disclosed iodine-containing etch compound with conventional etch gases can result in an increased etch rate while maintaining a high selectivity between the substrate and the layer to be etched associated with the disclosed iodine-containing etch compound.

[0085] The vapors of the disclosed etching compound and / or additives are introduced into a reaction chamber containing a substrate and a silicon-containing film. The vapors can be introduced into the chamber at flow rates ranging from about 0.1 sccm to about 1 slm. For example, for a 200 mm wafer size, the vapors can be introduced into the chamber at flow rates ranging from about 5 sccm to about 50 sccm. Alternatively, for a 450 mm wafer size, the vapors can be introduced into the chamber at flow rates ranging from about 25 sccm to about 250 sccm. Those skilled in the art will recognize that flow rates can vary depending on the tooling. The vapors of the disclosed etching compound and / or additives can be introduced into the reaction chamber premixed or separately.

[0086] The disclosed etching compounds and additives may be supplied in pure form or as blends with suitable solvents such as ethylbenzene, xylene, mesitylene, decane, or dodecane. The disclosed compounds and additives may be present in solvents at varying concentrations. The pure or blended solutions of the disclosed compounds and additives may be vaporized via conventional vaporization steps, such as direct vaporization, or by bubbling to generate vapor form. These pure or blended disclosed compounds and additives may be fed as liquids into a vaporizer before being introduced into the reactor, where they are vaporized. Alternatively, these pure or blended disclosed compounds and additives may be vaporized by conveying a carrier gas into a container containing the disclosed compounds and additives or by bubbling a carrier gas into the disclosed compounds and additives. The carrier gas may include, but is not limited to, Ar, He, N2, Xe, Kr, Ne, and mixtures thereof. The carrier gas and the disclosed compounds and additives are then introduced into the reactor as vapor.

[0087] If necessary, the container containing the disclosed compounds and additives can be heated to a temperature that allows the disclosed compounds and additives to be in the liquid phase and have sufficient vapor pressure. The container can be maintained at a temperature, for example, in the range of about 0°C to about 150°C. The piping from the bubbler to the etching tool can also be maintained at a temperature at or above the container temperature. Those skilled in the art will recognize that the temperature of the container can be adjusted in known ways to control the amount of vaporized disclosed compounds and additives.

[0088] Before being introduced into the reaction chamber, the vapors of the disclosed hydrofluorocarbon etching gas and additive gas can be mixed with an additional etching gas. This additional etching gas may constitute between approximately 0.01% v / v and approximately 99.99% v / v of the mixture introduced into the chamber.

[0089] The disclosed etching gas vapor and accompanying gases, such as inert gases and co-reactants, are activated by plasma to produce activated etching gas. This plasma decomposes the etching gas into radical forms or ions (i.e., activated etching gas). The plasma can be generated by applying RF or DC power. In a decoupled plasma etching reactor, the plasma can be generated using an RF source power ranging from about 25 W to about 100,000 W. The plasma can be generated remotely or within the reactor itself. The plasma can be generated under RF applied at two electrodes in, but not limited to, dual CCP or ICP modes. The RF frequency of the plasma can range from 100 kHz to 1 GHz. Different RF sources at different frequencies can be coupled and applied at the same electrode. The plasma RF pulse can be used as a bias power to further control molecular splitting and reactions at the substrate. Those skilled in the art will recognize the methods and apparatus suitable for this type of plasma processing.

[0090] Because the disclosed additives are used in conjunction with hydrofluorocarbons or fluorocarbons, the bias power can be lower compared to etching without the additives. In the disclosed methods, by applying the additives, the bias power can be at least approximately 10% lower than that without the additives, as illustrated in the following examples.

[0091] The disclosed method for forming a highly conductive sidewall passivation layer on a high aspect ratio patterned structure includes i) introducing etchant vapor into a reactor containing a substrate; ii) generating ion plasma in the reactor by applying source power using the etchant; iii) diffusing ions toward the substrate by applying reduced bias power, such that portions of the substrate not covered by the patterned mask layer on the substrate are selectively etched away to form a high aspect ratio patterned structure; and iv) maintaining the process running for a predetermined time and turning off the source power and low bias power until a highly conductive sidewall passivation layer is formed on the sidewall of the high aspect ratio patterned structure.

[0092] Here, the substrate has a film disposed thereon and a patterned mask layer disposed on the film. The etchant includes hydrofluorocarbons or fluorocarbons and additive compounds. The etchant may also include co-reactants and / or inert gases. After the etchant is introduced into the reactor, it is allowed to reach equilibrium. The reduced bias power can be at least 10% lower than the bias power of the etchant without additives. The predetermined time is in the range of 1 s to 1000 s. The ratio of hydrofluorocarbons or fluorocarbons to additive compounds is selected such that newly formed portions on the sidewall surface are passivated and protected from further etching. The ratio of hydrofluorocarbons or fluorocarbons to additive compounds introduced into the reactor can be varied from 1:99 to 99:1 by the flow rate.

[0093] Before introducing the etchant into the reactor, the reactor is evacuated to a high vacuum ranging from 0.001 mTorr to 100 mTorr. After the etching process, the reactor can be purged with an inert gas.

[0094] The temperature of the reactor chamber can be controlled by controlling the temperature of the substrate holder or by controlling the temperature of the reactor wall. Devices for heating the substrate are known in the art. The reactor wall is heated to a sufficient temperature to prevent condensation on the wall or reactor chamber, especially when using a spray head reactor in which the substrate temperature is higher than the wall temperature. Non-limiting exemplary temperature ranges (to which the reactor wall can be heated) include a range from about -100°C (LN temperature) to about 500°C, preferably from about 20°C to about 150°C, and more preferably from 20°C to about 110°C.

[0095] The pressure within the reaction chamber is maintained at a condition suitable for the substrate portion not covered by the patterned mask layer, where the etchant or process gas is not. Here, the etchant or process gas may include hydrofluorocarbon or fluorocarbon etching gases, additives, co-reactants, etc. For example, the pressure in the reactor may be maintained between approximately 1 mTorr and approximately 100 mTorr, preferably between approximately 1 mTorr and approximately 50 mTorr, more preferably between approximately 1 mTorr and approximately 10 mTorr, and even more preferably between approximately 1 mTorr and approximately 50 mTorr.

[0096] Etching conditions can be varied during the etching process. For example, parameters such as gas flow rate, plasma power, pressure, and temperature can be higher or lower during the initial etching phase than during the final etching phase, closer to the bottom of the hole or trench. Alternatively, different etching gases can be added at different points in the etching process to improve performance, such as reducing or increasing the polymer deposition rate.

[0097] The disclosed etching method offers high selectivity and no profile distortion for mask layers, photoresist, etch stop layers, and device channel materials in HAR structures (such as those with aspect ratios ranging from 1:1 to 200:1, such as DRAM and 3D NAND structures) and contact etching applications. Alternatively, aspect ratios range from 1:1 to 20:1 and from 21:1 to 200:1. The disclosed etching method is suitable for etching HAR patterned structures with aspect ratios between approximately 1:1 and approximately 200:1. Alternatively, the disclosed etching method is suitable for etching HAR-patterned structures having aspect ratios between approximately 1:1 and approximately 20:1, between approximately 21:1 and approximately 200:1, between approximately 1:1 and approximately 60:1, or between approximately 61:1 and approximately 200:1.

[0098] Example

[0099] The following non-limiting examples are provided to further illustrate embodiments of the invention. These examples are not intended to be exhaustive, nor are they intended to limit the scope of the invention described herein.

[0100] In the following examples, experiments were conducted using a commercially available LAM tool 4520XLe 200 mm (CCP dual-frequency plasma) or, alternatively, a commercially available AMEC 300 mm Primo SSC HD-RIE etcher. To demonstrate repeatability, each etching test was repeated at least three times. The standard deviation of the mean of the three measurements is shown in the graph as error bars. Subsequently, the polymer composition was investigated by X-ray photoelectron spectroscopy (XPS).

[0101] Example 1: Polymer Conductivity Measurement

[0102] Figures 1 to 3 The conductivity of C4H2F6 with and without additives CH3I, C4F9I, or SiH2I2 were measured on a planar wafer, respectively. Current (I)-voltage (V) was measured using a mercury probe. A drop of deionized water was added to the back side of the wafer to improve contact resistance, which helps reduce measurement noise at lower voltages. Under the same electric field strength, the iodine molecule additive added to the hydrofluorocarbon caused a higher measured current and a lower breakdown voltage through the polymer. The conductivity of C4H2F6 with the additive increased compared to C4H2F6 without the additive. See also Figures 1 to 3 The current difference in the field. As shown in Table 1, the conductivity was calculated under an electric field of 0.2 MV / cm, and the increase in conductivity under an electric field of 0.2 MV / cm is >10%.

[0103] Table 1

[0104] Example 2: Etching of ONON hole patterns using CH3I as an additive

[0105] Due to its promising performance on planar thin films (higher selectivity for aC masks and increased polymer conductivity), CH3I is incorporated into etching formulations including C4H2F6 for ONON (i.e., SiO / SiN alternating layers) hole patterning etching on patterned wafers or substrates. The patterned wafer has an ONON layer on which a hole-patterned amorphous carbon (aC) mask layer is deposited. The etching formulation may also include O2.

[0106] Four conditions were tested for initial screening: C4H2F6 / CH3I flow rates of 30 / 10 sccm, 35 / 5 sccm, 40 / 5 sccm, and 40 / 10 sccm, with the 30 / 10 sccm and 35 / 5 sccm having the same total gas flow rate. Due to the strong polymerizability of CH3I, etch termination was observed via SEM images at CH3I flow rates of 10 sccm or higher. The 40 / 5 sccm condition showed improved etch selectivity; however, further adjustments to the etch formulation are needed. The SEM conditions were as follows: Accelerating voltage: 5.0 kV; Emission current: 20 μA; Magnification: × 30.0 k.

[0107] CH3I exhibits strong polymerizability; its addition to the ONON etch composition at a flow rate of 10 sccm or higher can clog the patterned mask layer and further lead to etch termination. With the addition of CH3I to the etch formulation, the O2 flow rate process window shifts from 68 sccm to 74-76 sccm. For the optimized CH3I formulation: ONON etch rate (ER): 510 nm / min (without CH3I, the measured ONON ER is 516 nm / min); ONON / aC selectivity: 11.2–12 (without CH3I, the ONON / aC selectivity is 11.4–12). Figures 4 to 9 The comparisons show the ER, selectivity, sidewall bend, ellipticity, and critical size (CD) of C4H2F6 with and without CH3I additive. Overall, the formulation with CH3I shows less dependence on bias power (ONON etch rate, selectivity, bend, ellipticity, profile CD) compared to the formulation without CH3I.

[0108] More specifically, such as Figure 6 As shown, at a bias power of 7000 W, adding CH3I to the formulation did not show a significant change in the ellipticity of the aC mask apertures; the ellipticity measured for the formulation without CH3I was 93%, and for the formulation with CH3I, it was 94%. At a bias power of 5600 W, for the formulation without CH3I, the aC mask profile deteriorated with decreasing bias power, while a smaller effect was observed for the formulation with CH3I. At a bias power of 4200 W, the formulation with CH3I showed improved etching performance, including ER, selectivity, aC mask ellipticity, and tilt angle. Table 2 summarizes the etching performance.

[0109] Table 2. Summary of Etching Performance

[0110] In summary, the surface passivation (also known as the polymer layer) on the etch front and sidewalls characterized by the addition of CH3I is improved, and this passivation changes with varying plasma etching conditions (RF power, process time, etc.). Furthermore, the addition of CH3I as an additive to the hydrofluorocarbon etching gas reduces the bias power by 40% without compromising etching performance such as etch rate, selectivity, ellipticity, and profile CD.

[0111] Example 3: Polymer chemical composition and polymer conductivity

[0112] Substrate: To obtain the I-V characteristics of only the polymer, a low-resistivity Si substrate (less than 0.02 Ohm.cm) was used instead of the SiO2 substrate for polymer deposition. The Si substrate was cut into 1-inch × 1-inch specimens for I-V measurements using a mercury probe.

[0113] Polymer Deposition: For C4F8, C4H2F6, C4F9I, C4F8 + C4F9I, and C4H2F6 + C4F9I, the same deposition process conditions were used; the thickness of the deposited polymer was measured by an ellipsometer; for the polymer on the ion-blocking region, the thickness at a position 1 mm from the edge of the shielded specimen was measured.

[0114] Lam Tool Experimental Conditions: RF source power: 750 W; bias power: 1500 W; Ar / etch gas (or gas mixture) / O2: 250 / 15 / 0; etch time: 30 seconds.

[0115] Figure 10 are the various polymer chemical compositions and polymer conductivities. The current (I)-voltage (V) measurements were the same as those in Example 1. As shown, at the same electric field strength, the addition of hydrofluorocarbon iodine molecule additives caused a higher measured current through the polymer and a lower breakdown voltage, and the conductivities of various polymers and iodine molecule additives at 0.2 MV / cm were as follows: C4F9I > C4H2F6 + C4F9I > C4F8 + C4F9I > C4H2F6 > C4F8. Polymers with a higher C-C:C-Fx / C-I ratio have a higher breakdown voltage and are stronger electrically. C-F x bonds may contribute to the polymer conductivity. The conductivity of polymers rich in C-C bonds is less than that of polymers rich in C-F x bonds.

[0116] Table 3 shows the C-C:C-F x / C-I (x is an integer) bond concentration ratio. The C-C:C-F x / C-I bond concentration ratio from low to high is C4F9I < C4F8 + C4F9I < C4F8 < C4H2F6 + C4F9I < C4H2F6. C-C bonds are non-polar covalent bonds; C-Fx / C-I bonds are polar covalent bonds. The conductivity was calculated at an electric field of 0.2 MV / cm, and the increase in conductivity at an electric field of​​​​​​​While it is challenging to explain how polymer chemical composition and conductivity are related due to different conduction mechanisms under varying electric fields, in general, adding iodine additives to polymers to make them more conductive reduces the bias power by at least about 10% compared to the case without the additives, or even eliminates the need for bias power, without compromising etching performance such as etching rate, selectivity, ellipticity, profile CD, etc., as shown in Example 2.

[0119] It should be understood that many additional changes in details, materials, steps, and arrangements of parts that have been described and elucidated to explain the nature of the invention can be made by those skilled in the art within the principles and scope of the invention as set forth in the appended claims. Therefore, the invention is not intended to be limited to the specific embodiments given above and / or in the drawings.

[0120] Although embodiments of the invention have been shown and described, those skilled in the art can modify them without departing from the spirit or teachings of the invention. The embodiments described herein are exemplary and not limiting. Many variations and modifications of the compositions and methods are possible and are within the scope of the invention. Therefore, the scope of protection is not limited to the embodiments described herein, but is defined only by the following claims, the scope of which should include all equivalents of the subject matter of the claims.

Claims

1. A method for forming a HAR structure in a substrate during a high aspect ratio (HAR) etching process in a reaction chamber, the method comprising: The substrate is sequentially or simultaneously exposed to an etchant including hydrofluorocarbons or fluorocarbons and SiH2I2 vapor, the substrate having a film disposed thereon and a patterned mask layer disposed on the film; Activated plasma to generate activated hydrofluorocarbons or fluorocarbons and activated SiH2I2; as well as This allows for an etching reaction between the film not covered by the patterned mask layer and the activated hydrofluorocarbon or fluorocarbon compound and the activated SiH2I2 to selectively etch the film from the patterned mask layer, thereby forming a HAR patterned structure. A highly conductive sidewall passivation layer is formed on the sidewall of the HAR patterned structure.

2. The method of claim 1, further comprising the step of introducing an oxidant into the reaction chamber, wherein the oxidant is selected from O2, O3, CO, CO2, NO, N2O, NO2, H2O, H2O2, COS, SO2, and combinations thereof.

3. The method of claim 1, further comprising the step of introducing an inert gas into the reaction chamber, wherein the inert gas is selected from the group consisting of He, Ar, Xe, Kr, Ne and N2.

4. The method according to any one of claims 1 to 3, wherein, The conductivity of the highly conductive sidewall passivation layer formed with the activated hydrofluorocarbon or fluorocarbon and the activated SiH2I2 is at least 10% higher than that of the highly conductive sidewall passivation layer formed with the activated hydrofluorocarbon or fluorocarbon without the addition of the activated SiH2I2.

5. The method of claim 1, wherein, The hydrofluorocarbon or fluorocarbon includes CF4, CH3F, C2F6, C3F8, C2HF5, C5F8, C6F6, C4F6, C4F8, C1 to C5 saturated or unsaturated straight-chain, branched, cyclic hydrofluorocarbons such as C4H2F6, CHF3, CH2F2, or combinations thereof.

6. The method of claim 1, wherein, The hydrofluorocarbon or fluorocarbon is C4H2F6.

7. The method according to any one of claims 1 to 3 and 5 to 6, wherein, The film is a silicon-containing film containing O and / or N and optionally containing dopants such as B, C, P, As, Ga, In, Sn, Sb, Bi and / or Ge, and combinations thereof.

8. The method according to any one of claims 1 to 3 and 5 to 6, wherein, The patterned mask layer is an aC layer, a doped aC layer, a photoresist layer, an antireflection layer, an organic planarization layer, a polysilicon layer, a metal oxide layer such as oxides of Ti, Al, Zr, Hf, etc., and combinations thereof.

9. The method according to any one of claims 1 to 3 and 5 to 6, wherein, The HAR patterned structure formed in the membrane has an aspect ratio between 1:1 and 200:

1.

10. The method of any one of claims 1 to 3 and 5 to 6, further comprising introducing an additional etching gas into the reaction chamber, wherein the additional etching gas is selected from the group consisting of: 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 ( Shun Mode -C4H2F6), hexafluoroisobutylene (C4H2F6), trans-1,1,2,2,3,4-hexafluorocyclobutane (C4H2F6) trans -C4H2F6), 1,1,2,2,3-pentafluorocyclobutane (C4H3F5), 1,1,2,2-tetrafluorocyclobutane (C4H4F4), and cis-1,1,2,2,3,4-hexa ...6), 1,1,2,2,3,4-hexafluorocyclobutane (C4H3F5), 1,1,2,2-tetrafluorocyclobutane (C4H4F4), and cis-1,1,2,2,3,4-hexafluorocyclobutane (C4H3F5), 1,1,2,2-te Cis -C4H2F6) and its combinations.

11. A method for forming a HAR patterned structure, the method comprising the steps of: A substrate is sequentially or simultaneously exposed to vapors of C4H2F6 and SiH2I2, the substrate having a film disposed thereon and a patterned mask layer disposed on the film; Activated plasma to generate activated C4H2F6 and activated SiH2I2; as well as This allows for an etching reaction between the film not covered by the patterned mask layer and the activated C4H2F6 and SiH2I2 to selectively etch the film from the patterned mask layer, thereby forming the HAR patterned structure. A highly conductive sidewall passivation layer is formed on the sidewall of the HAR patterned structure.

12. The method of claim 11, further comprising the step of introducing an oxidant into the reaction chamber, wherein the oxidant is selected from O2, O3, CO, CO2, NO, N2O, NO2, H2O, H2O2, COS, SO2, and combinations thereof.

13. The method of claim 11, further comprising the step of introducing an inert gas into the reaction chamber, wherein the inert gas is selected from the group consisting of He, Ar, Xe, Kr, Ne and N2.

14. The method according to any one of claims 11 to 13, wherein, The conductivity of the highly conductive sidewall passivation layer formed with the activated C4H2F6 and the activated SiH2I2 is at least 10% higher than that of the highly conductive sidewall passivation layer formed with the activated C4H2F6 without the addition of the activated SiH2I2.

15. The method according to any one of claims 11 to 13, wherein, The HAR patterned structure formed in the membrane has an aspect ratio between 1:1 and 200:

1.

16. The method of any one of claims 11 to 13, further comprising introducing an additional etching gas into the reaction chamber, wherein the additional etching gas is selected from the group consisting of: 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 ( Shun Mode -C4H2F6), hexafluoroisobutylene (C4H2F6), trans-1,1,2,2,3,4-hexafluorocyclobutane (C4H2F6) trans -C4H2F6), 1,1,2,2,3-pentafluorocyclobutane (C4H3F5), 1,1,2,2-tetrafluorocyclobutane (C4H4F4), and cis-1,1,2,2,3,4-hexa ...6), 1,1,2,2,3,4-hexafluorocyclobutane (C4H3F5), 1,1,2,2-tetrafluorocyclobutane (C4H4F4), and cis-1,1,2,2,3,4-hexafluorocyclobutane (C4H3F5), 1,1,2,2-te Cis -C4H2F6) and its combinations.

17. A method for forming a HAR structure in a substrate during a high aspect ratio (HAR) etching process in a reaction chamber, the method comprising: The substrate is sequentially or simultaneously exposed to vapors of etchant and additive compounds, including hydrofluorocarbons or fluorocarbons, the substrate having a film disposed thereon and a patterned mask layer disposed on the film; The substrate is maintained at a temperature ranging from -100°C to 500°C; Activated plasma to produce activated hydrofluorocarbons or fluorocarbons and activated additive compounds; as well as This allows for an etching reaction between the film not covered by the patterned mask layer and the activated hydrofluorocarbon or fluorocarbon compound and the activated additive compound to selectively etch the film from the patterned mask layer, thereby forming a HAR patterned structure. A highly conductive sidewall passivation layer is formed on the sidewall of the HAR patterned structure.

18. The method of claim 17, wherein, The conductivity of the highly conductive sidewall passivation layer formed with the activated hydrofluorocarbon or fluorocarbon compound and the activated additive compound is at least 10% higher than that of the highly conductive sidewall passivation layer formed with the activated hydrofluorocarbon or fluorocarbon compound without the addition of the activated additive compound.

19. The method of any one of claims 17 and 18, wherein, The additive compound contains silicon, carbon, and / or iodine, and has the following formula: C n R 1 R 2 R 3 I, SiR 1 R 2 R 3 I, SiR 1 R 2 I x F (2-x) , SiRI y F (3-y) , SiI z F (4-z) ,or C n F (2n+1) I Where n = 1 to 10; x = 1-2; y = 1-3; z = 1-3; R, R 1 R 2 and R 3 Each is independently selected from H, C1-C 10 Straight-chain, branched, or cyclic; saturated or unsaturated; aromatic, heterocyclic, partially or fully fluorinated, substituted or unsubstituted hydrocarbon groups; R 1 and R 2 R 2 and R 3 、or R 1 and R 3 They can also be linked to form cyclic groups.

20. The method of any one of claims 17 and 18, wherein, The additive compound is selected from or .

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