Low gwp plasma etching process using cf

Abstract

An etching method for forming a hole in a substrate includes exposing the substrate to an etching gas containing acyclic C6F12; converting the etching gas into a plasma; allowing an etching reaction to occur between the plasma and one or more silicon-containing films contained in the substrate, such that the one or more silicon-containing films are selectively etched relative to a patterned masking layer deposited on the one or more silicon-containing films to form the hole therein and form volatile byproducts; and removing the volatile byproducts. Compared to etching processes using etching gases with a GWP100 > 30, CO2eq emissions of these volatile byproducts are reduced.

Description

[Technical Field]

[0001] This invention relates to a plasma etching patterning method for silicon materials with low global warming potential (GWP) etching gases and low GWP emissions, the method utilizing C6F12 and other etching gas co-reactants, particularly utilizing C6F12 and other etching gas co-reactants under etching conditions. [Previous Technology]

[0002] Traditionally, silicon plasma etching is used in patterning processes for manufacturing semiconductor wafer devices, and is performed using fluorine-containing gases (due to the formation of SiF4 as the main byproduct). For patterning etching of silicon materials (such as SiO2), carbon-containing fluorine molecules are often used, as a carbon- and fluorine polymer is formed to protect the sidewalls of the etched structure. The addition of ion bombardment in the etching process accelerates the chemical reaction in the vertical direction, resulting in the formation of vertical sidewalls perpendicular to the substrate along the edges of the masked features (Manos and Flamm, Plasma Etching An Introduction, Academic Press, Inc., 1989). However, most fluorocarbon etching gases have high global warming potential (GWP) values ​​due to CF bond absorption in the 1000–1500 cm⁻¹ IR spectral range (which overlaps with the Earth's output radiation spectral range). This strong absorption, along with the strong bond strength of the CF bonds, results in high heat-trapping effects of fluorocarbon molecules over long periods, and thus contributes to global warming. C4F8 is a common silicon etchant used in various patterning processes for manufacturing semiconductor devices. However, it has a high global warming impact, with a global warming effect 9,540 times that of CO2.

[0003] C6F12 is a known etchant from the prior art references listed below. It has been disclosed in formulations for applications including etching SiO2, SiN, and Si. C6F12 is known to have cyclic and acyclic isomers. C6F12 is known to be mixable with other gases, including fluorocarbons, hydrofluorocarbons, inert gases, and oxygen (limitations are described below). Acyclic C6F12 is known to have a lower GWP gas compared to cyclic C6F12 isomers. Low-GWP alternative etchants are needed to replace high-GWP fluorocarbon etchants.

[0004] JP 2012043869 discloses the etching gas C6F12. C6F12 isomers C6F12(A) (CAS No.: 2070-70-4) and C6F12(B) (CAS No.: 1584-03-8) are disclosed. The etching rate and selectivity of the two C6F12 isomers relative to C4F8 are disclosed. It should be noted that JP 2012043869 only adds a small amount of C6F12 and only shows it mixed with C5F8. Etching with C6F12 alone is not discussed in the examples, and SiN etching is not addressed. When C6F12 + C5F8 is mixed, a higher etching rate than C4F8 + C5F8 is observed, but only by a factor of 1.2.

[0005] US 7022616 discloses etching Si using SiO2 as a mask. The following different types of gases can be used. Any one of these gases can be used alone, or multiple gases can be mixed. That is, unsaturated fluorinated carbon compound gases with one or more double or triple bonds, represented by CxFy (y < 2x+2), such as: C2F4, C2F2, C3F6, C3F4, C4F8, C4F6, C4F4, C4F2, C5F10, C5F8, C5F6, C5F4, C6F12, C6F10, C6F8, C6F6, etc.

[0006] JP ​​3253215 discloses an etching method and etching apparatus for selectively etching SiO2 from SiN. Examples of carbon halide-based gases include CxFy-based gases having a y²x + 2 relationship. For example, C4F8 can be used. Those that satisfy the correlation expression y = 2x + 2 include saturated fluorocarbon gaseous compounds such as CF4, C3F8 and C5F12, C7F16, C9F20, C2F6, C4F1, C6F14, C8F18 and C10F22, and those that satisfy the correlation expression y < 2x + 2 include unsaturated fluorocarbon gaseous compounds having at least one double or triple bond, such as C2F4, C2F2, C3F7, C3F4, C4F8, C4F6, C4F4, C4F2, C5F10, C5F8, C5F6, C5F4, C6F12, C6F10, C6F8, C6F6, etc.

[0007] US 7153779 discloses a method for eliminating streaks and surface roughness caused by dry etching using a fluorocarbon gas component of an etching gas, wherein the etching gas may comprise a single organic fluorocarbon gas used alone, or a mixture of two or more organic fluorocarbon gases. The organic fluorocarbon gas may include one or more fluorocarbon gases having 1-2 carbons of the general formula CxHyFz, wherein x refers to 1 to 2, y to 0 to 3, and z to 2x-y+2. Examples of such 1-2 carbon fluorocarbon gases include CF4, CHF3, CH2F2, C2F6, etc. The organic fluorocarbon gas may also include one or more higher molecular weight fluorinated hydrocarbons having 3-6 carbons of the general formula CxHyFz, wherein x refers to 3 to 6, y to 0 to 3, and z to 2x-y when the fluorinated hydrocarbon is cyclic, and z to 2x-y+2 when the fluorinated hydrocarbon is acyclic. Examples of cyclic fluorocarbons with 3-6 carbon atoms include C4H2F6 and C6F12, where C6F12 and C4H2F6 are cyclic rather than linear.

[0008] US 7794616 discloses an etching gas comprising a main gas based on an unsaturated fluorocarbon. Another etching gas comprises a main gas based on an unsaturated fluorocarbon and an additive gas comprising a gas based on a cyclic saturated fluorocarbon, represented by CXF2X (x represents 5 or a greater natural number). In this case, the additive gas system is either C5F10 or C6F12. The inventors have discovered that by adding an additive gas comprising a gas based on a cyclic saturated fluorocarbon, represented by CxF2x (x represents 5 or a greater natural number), to a main gas comprising an unsaturated fluorocarbon, the etching rate can be increased while maintaining high etching selectivity. Furthermore, in this case, the etching selectivity can be further increased compared to the case where a gas based on a straight-chain saturated fluorocarbon is added. Furthermore, the additive gas can be either C5F10 or C6F12.

[0009] US Patent 2015294880, granted to Anderson et al., discloses the use of various hydrofluorocarbon gases, including C4H2F6, for etching silicon-containing layers in high aspect ratio oxide etching. It discloses QMS (quadrupole mass spectrometry) of C4H2F6 (CAS#: 382-10-5) along with C4F8, C4F6, and other gases. The primary form of C4F2F6 is CF3. They also revealed that different fluorocarbon etching gases (including isomers) exhibit different etching properties and compositions in QMS.

[0010] Therefore, both a low-GWP etching gas that functions in the etching process and a gas that decomposes in the plasma and generates low-GWP byproducts are required. [Summary of the Invention]

[0011] An etching method for forming a hole in a substrate is disclosed, the method comprising: exposing the substrate to an etching gas containing non-cyclic C6F12; converting the etching gas into a plasma; allowing an etching reaction to occur between the plasma and one or more silicon-containing films contained in the substrate, such that the one or more silicon-containing films are selectively etched relative to a patterned masking layer deposited on the one or more silicon-containing films to form the hole therein and form volatile byproducts; and removing the volatile byproducts. The disclosed deposition method may include one or more of the following features: • Further includes adding one or more hydrofluorocarbon or fluorocarbon etching gases to the etching gas, wherein the one or more hydrofluorocarbon or fluorocarbon etching gases are selected from C4F6, C4F8, C4H2F6, CHF3, CH2F2, CH3F, CF4, C2F6, C3F8, SF6, NF3, C2F4, C3F6, C4F10, C5F8, C6F6, C1-C7CxFy molecules (x and y are integers), C2H2F2, C2H5F, C3H7F, C3H2F6, C2HF5, C1-C7CxFyHz molecules (where x, y, and z are integers), or combinations thereof; • Further includes adding C2H2F2 to the etching gas; • Further, this includes adding H2, SF6, NF3, NH3, Cl2, BCl3, BF3, Br2, F2, FNO, FNO3, HBr, HCl, HI, IF5, IF7, HF, B2H6, or a P-containing gas selected from PF3, PCl3, PBr3, PH3, POCl3, PF5, POF3, PH3PCl5, PBr5, PF2BrO, PCl3O, PF2Br, or PR3 (wherein R-series alkyl or fluorinated alkyl) to the etching gas; Further, it includes adding O2, CO, CO2, NO, NO2, N2O, SO2, H2S, COS, O3, OF2, SOF2, SO2F2, CxOyFzSmHn selected from (CF3SO2)2O or CF4SO2 (where x, y, z, m, and n are integers), CxOyFzNmHn selected from CF3N=O (where x, y, z, m, and n are integers), or CxOyFz selected from COF2 or C2O2F2, and CxOyFzHm selected from alcohols, ketones, acids, and esters selected from CF3OH, CF3OCF3, (CF3)2C=O, CF3COOH, or combinations thereof (where x, y, z, and m are integers); • Further, it includes adding an inert gas to the etching gas, wherein the inert gas is selected from Ar, Kr, Xe, Ne, N2, He, or combinations thereof;• This acyclic C6F12 system comprises isomers of C6F12 with the following CAS numbers: 2070-70-4, 1584-03-8, 755-25-9, 1584-00-5, 360-57-6, 1584-02-7, 3709-71-5, 1584-00-5, 3709-70-4, 359-72-8, 67483-02-7 67899-37-0, 137202-54-1, 81018-66-8, 87743-93-9, 287101-12-6, 87744-03-4, 71186-98-6, 71186-97-5, 66319-89-9, 58621-70-8, 873536-26-6, or 13429-24-8; • The acyclic C6F12 is an isomer of C6F12 with the following CAS number: 2070-70-4; • The acyclic C6F12 is an isomer of C6F12 with the following CAS number: 3709-71-5; • The temperature range of the substrate is approximately -196°C to approximately 300°C; • The temperature range of the substrate is approximately -196°C to approximately 60°C; • The temperature of the substrate is below approximately -20°C; • The temperature range of the substrate is approximately -196°C to approximately -50°C; • After forming the hole, the temperature of the substrate is raised to greater than -70°C; and • Compared with etching processes using etching gases with GWP100 > 30, the CO2eq emissions of these volatile byproducts are reduced.

[0012] An etching method for forming a hole in a substrate is also disclosed, the method comprising: maintaining the substrate at a temperature ranging from about -196°C to about 300°C; exposing the substrate to an etching gas containing acyclic C6F12 (CAS No.: 2070-70-4 or CAS No.: 3709-71-5) entering a reaction chamber; adding C2H2F2 to the etching gas; converting the etching gas into a plasma; allowing an etching reaction to occur between the plasma and one or more silicon-containing films contained in the substrate, such that the one or more silicon-containing films are selectively etched relative to a patterned masking layer deposited on the one or more silicon-containing films to form the hole therein; and removing volatile byproducts. The disclosed deposition method may include one or more of the following features: • Further including the addition of a phosphorus-containing gas and an HF-containing gas; • Further including the addition of a fluorocarbon or hydrofluorocarbon gas, an oxidizing gas, and an inert gas; • The temperature range of the substrate is from about -196°C to about 60°C; • The temperature of the substrate is below about -20°C; • The temperature range of the substrate is from about -196°C to about -50°C; • After the hole is formed, the temperature of the substrate is raised to greater than -70°C; and • The CO2eq emissions of these volatile byproducts are reduced compared to etching processes using etching gases with GWP100 > 30.

[0013] An etching method for forming a hole in a substrate is also disclosed, the method comprising: maintaining the substrate at a temperature ranging from about -196°C to about 300°C; exposing the substrate to an etching gas containing non-cyclic C6F12 (CAS No.: 2070-70-4) entering a reaction chamber; adding C2H2F2 to the etching gas; converting the etching gas into a plasma; allowing an etching reaction to occur between the plasma and one or more silicon-containing films contained in the substrate, such that the one or more silicon-containing films are selectively etched relative to a patterned masking layer deposited on the one or more silicon-containing films to form the hole therein; and removing volatile byproducts. The disclosed deposition method may include one or more of the following features: • Further including the addition of a phosphorus-containing gas and an HF-containing gas; • Further including the addition of a fluorocarbon or hydrofluorocarbon gas, an oxidizing gas, and an inert gas; • The temperature range of the substrate is approximately -196°C to approximately 60°C; • The temperature of the substrate is below approximately -20°C; • The temperature range of the substrate is approximately -196°C to approximately -50°C; • After the hole is formed, the temperature of the substrate is raised to greater than -70°C; and • The CO2eq emissions of these volatile byproducts are reduced compared to etching processes using etching gases with GWP100 > 30. Symbols and Nomenclature

[0014] The following detailed description and claims utilize many abbreviations, symbols and terms commonly known in the art, and include:

[0015] As used herein, the indefinite article “a / an” means one or more species.

[0016] As used herein, “about” or “around / approximately” in the text or request means ± 10% of the value.

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

[0018] The term "substrate" refers to one or more materials on which a process is performed. A substrate can refer to a wafer having one or more materials on which a process is 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 (including but not limited to crystalline, amorphous, porous, etc.), silicon-containing layers (including but not limited to SiO2, SiN, SiON, SiCOH, etc.), metal or metal-containing layers (including but not limited to copper, cobalt, ruthenium, tungsten, platinum, palladium, nickel, ruthenium, gold, etc.) or combinations thereof. Furthermore, a substrate can be planar or patterned. A substrate can be an organically patterned carbon iodide film. The substrate may include oxide layers of dielectric materials (e.g., ZrO2-based materials, HfO2-based materials, TiO2-based materials, rare earth oxide-based materials, ternary oxide-based materials, etc.) used as electrodes in field-effect transistors (FETs) such as FinFET, MOFSET, GAAFET (Gate All-Around FET), strip FET, nanosheet, fork FET, complementary FET (CFET), MEMS, 3D NAND, MIM, DRAM, or FeRam device applications, or nitride-based films (e.g., TaN, TiN, NbN). The substrate may include alternating layers of oxides (e.g., SiO) and nitrides (e.g., SiN). Those skilled in the art will recognize that the terms "film" or "layer" as used herein refer to a material of a certain thickness laid or spread on a surface, and that surface may be trenches or lines. Throughout this specification and the claims, the wafer and any associated layers thereon are referred to as the substrate. The substrate can be any solid having functional groups on its surface that tend to react with reactive heads that self-assembled monolayers (SAMs), and can include, but is not limited to, 3D objects or powders.

[0019] The term "wafer" or "patterned wafer" refers to a wafer having a stack of films on a substrate, wherein at least the topmost film of the stack of films has morphological features or patterns that have been generated in a step prior to etching, and a patterned topmost film is formed for patterning etching.

[0020] As used herein, the term "processing" includes patterning, exposure, development, etching, deposition, cleaning and / or removal of byproducts, as required when forming the described structure.

[0021] The term "deposit" refers to a series of processes in which material at the atomic or molecular level is deposited as a thin layer from a gaseous (vapor) state onto a wafer surface or substrate. Chemical reactions are involved in the process, occurring either after the generation of reactive gases by plasma or after the reactive gases are activated by heating. The plasma can be, but is not limited to, capacitively coupled plasma (CCP), inductively coupled plasma (ICP), electron cyclotron resonance (ECR) plasma, or microwave plasma. Suitable commercially available plasma etching chambers include, but are not limited to, the Lam Research Dual CCP reactive ion etching dielectric etching product family sold under the trademarks Flex™ or Tokyo Electron Tactras™ or Episode™UL. Non-plasma exposure steps can be performed in a different chamber than the plasma exposure steps.

[0022] 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).

[0023] The term "high aspect ratio (HAR)" refers to an aspect ratio ranging from about 1:1 to about 500:1, preferably from about 20:1 to about 400:1.

[0024] The term "high aspect ratio etching" refers to the formation of a hole pattern in a target film by means of plasma etching, wherein the aspect ratio of the hole structure formed exceeds 5.

[0025] It should be noted that the terms "film," "layer," and "material" are used interchangeably herein. It should be understood that a film may correspond to or be associated with a layer or a material, and a layer may refer to both a film and a material. Furthermore, those skilled in the art will recognize that, as used herein, the terms "film," "layer," or "material" refer to a material of a certain thickness laid or spread on a surface, and that surface may range from as large as an entire wafer to as small as a trench or line.

[0026] It should be noted that in this document, the terms “aperture”, “via”, “hole”, “trench” and “structure” are used interchangeably to refer to openings formed in a semiconductor structure.

[0027] As used herein, the abbreviation "NAND" refers to a "Negative 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.

[0028] It should be noted that, in this document, the terms "etching gas" and "etching agent" are used interchangeably when the etching gas is in a gaseous state at room temperature and ambient pressure. It should be understood that etching gas may correspond to or be associated with an etching agent, and the etching agent may refer to the etching gas.

[0029] The term "doping" is used interchangeably in processes that incorporate one or more elements into a film by various methods that can chemically or physically combine them, and in processes that intentionally incorporate atoms of different elements into a film composition. One or more elements can be interstitially doped or alternatively doped within the film.

[0030] The elements in this document are referred to by the standard abbreviations of the periodic table. It should be understood that elements may be referred to by these abbreviations (for example, Si refers to silicon, N refers to nitrogen, O refers to oxygen, C refers to carbon, H refers to hydrogen, F refers to fluorine, etc.).

[0031] A unique CAS registry number (i.e., "CAS") assigned by the Chemical Abstracts Service is provided to identify the specific molecule disclosed.

[0032] As used herein, the term "hydrofluorocarbon" refers to a saturated or unsaturated functional group containing carbon, fluorine and hydrogen atoms.

[0033] As used herein, the term "fluorocarbon" refers to a saturated or unsaturated functional group containing fluorine and carbon atoms.

[0034] As used herein, the term "fluorochemical" is used interchangeably with the terms hydrofluorocarbon and fluorocarbon.

[0035] As used herein, the term “GWP” refers to global warming potential, typically measured on a 100-year timescale and compared to CO2.

[0036] As used herein, the term "GWP100" refers to a GWP that is over 100 years old.

[0037] As used herein, the terms "CO2eq" or "CO2e" refer to CO2 equivalent emissions, that is, greenhouse gas emissions equivalent to CO2 by using the mass of the emitted substance and multiplying it by the substance's GWP. This allows for equivalent comparisons of process emissions between two different etching gases using the GWP of each molecule.

[0038] As used herein, “CO2 emissions (CO2e)” or “CO2 equivalent emissions (CO2eq)” are used interchangeably to refer to emissions relative to the effects of global warming.

[0039] As used herein, the terms "etching gas" or "etching agent" refer to one or more gaseous materials used for etching. The material source of one or more materials in the container providing the vapor for etching may contain a gas, liquid, or solid form of that material and / or a combination thereof. The etching gas and / or etching agent may be a single gaseous material or a chemical. The etching gas and / or etching agent may be a mixture of more than one gaseous material or chemical.

[0040] In this document, a range may be expressed as from about one specific value and / or about another specific value. When such a range is expressed, it should be understood that another embodiment is from that one specific value and / or to that other specific value, together with all combinations within said range. Any and all ranges listed herein include their endpoints (i.e., x = 1 to 4, or the range of x is 1 to 4, including x = 1, x = 4, and x = any number in between), regardless of whether the term "inclusive" is used.

[0041] In this document, references to "one embodiment" or "implementation" 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 one embodiment" appearing in different places in the specification does not necessarily refer to the same embodiment in all instances, and a single or alternative embodiment is not necessarily mutually exclusive with other embodiments. The same applies to the term "implementation".

[0042] As used herein, the term "exemplary" is used to mean serving as an instance, example, or illustration. Any aspect or design described herein as "exemplary" is not necessarily to be construed as superior to or advantageous to other aspects or designs. Rather, the use of the term "exemplary" is intended to present the concept in a concrete manner.

[0043] Furthermore, the term "or" is intended to mean an inclusive "or" rather than an exclusive "or". That is, unless otherwise stated or clear from the context, "X adopts A or B" is intended to mean any natural inclusive arrangement. That is, if X adopts A; X adopts B; or X adopts both A and B, then "X adopts A or B" is satisfied in any of the foregoing cases. Furthermore, the article "a / an" as used in this application and the appended claims should generally be interpreted as meaning "one or more" unless otherwise stated or clearly indicated from the context to the singular form.

[0044] The term “comprising” in the request is an open transitional term, meaning that the subsequently determined elements of the request are a non-exclusive list (i.e., anything else may be additionally included and remain within the scope of “comprising”). “Comprising” is defined herein as necessary to cover the more restrictive transitional terms “substantially consists of” and “consisting of”; therefore, “comprising” can be replaced by “substantially consists of” or “consisting of” and remain within the clearly defined scope of “comprising”.

[0045] The term "provide" in the claims is defined as meaning to supply, provide, make available, or prepare something. The steps can, conversely, be performed by any actor in the absence of explicit language in the claims.

Implementation Method

[0047] A method for etching silicon-containing materials using perfluorocarbons (PFCs) and hydrofluorocarbons (HFCs) is disclosed, which is widely used in semiconductor manufacturing. PFCs and HFCs are sources of both the "F" used to etch silicon (producing SiF4 byproducts) and the polymers used to form sidewall protection during patterning. However, commonly used PFCs and HFCs typically have high global warming potential (GWP) values. Table 1 below lists the GWPs of commonly used etching gases in the semiconductor industry, along with other molecules that may be plasma byproducts and other chemicals. PFC molecules (such as C2F6, C3F8, C4F8, etc.) are good SiO2 etchants. However, PFCs have particularly high GWPs. Furthermore, byproducts from etching can include NO2, CO, CO2, COF2, SiF4, etc. [Table 1.] GWP100 values gas GWP 100 CHF3 12400 C2F6 11100 C3F8 9290 C4F8 9540 C5F 12 9220 C6F 14 8620 CF4 6630 C5F8 90 CH2F2 677 NO2 265 CO 2.1 C4H2F6 4 CO2 1 COF2 < 1 CF3I < 1 C4F6 < 1 C2H2F2 < 1 C3F6 < 1

[0048] The main way to reduce the GWP of fluorinated compound gases is by adding double bonds. This allows for comparison of the GWP of C3F8 versus C3F6, C5F12 versus C5F8, etc. However, adding double bonds may cause the molecules to polymerize more in the plasma, resulting in a lower SiO2 etching rate, but potentially higher selectivity for masking materials (such as carbon materials like aC). Ideally, the addition of double bonds would result in a lower GWP and an increased etching rate. Fully fluorinated molecules (PFCs) are ideal for etching SiO2 patterns with different masking materials (like aC). For etching nitride materials, or alternating layers of SiO2 and SiN (as used in 3D NAND technology), hydrofluorocarbon gases can be added because H is beneficial for etching SiN layers. Therefore, C4F6 and / or C4F8 can be mixed with hydrofluorocarbon gases (such as CHF3, CH2F2, CH3F, etc.). Hydrofluorocarbon (HFC) gases with double bonds and CF3 moieties exist, such as C4H2F6, which has a low glycemic power (GWP) and, according to the literature, should provide good etch performance. Here, C6F12 is disclosed as an etch gas for etching silicon materials in plasma etching processes to manufacture semiconductor wafers, such as those used in the manufacture of 3D NAND flash memory and DRAM wafers, as an alternative to high-GWP etch gases. Etching such high aspect ratio structures using conventional fluorocarbon plasma etching methods is very challenging, especially as we move towards new technology nodes. Other applications may include plasma etching processes in logic etching (BEOL, etc.). Another problem with conventional fluorocarbon and HFC gases is that they can have high GWPs, and when exposed to high-power plasma, they can break down and potentially form substances with high GWPs, as these substances exist in the plasma chamber in radical and ionic form. These substances can react with each other and with other internal components of the wafer and chamber, thus forming new substances. Due to the complexity of plasma processes and the materials decomposed, it is difficult to predict the byproducts and complex byproducts of the emissions. These materials then exit the plasma etching chamber and are discharged. In some cases, these materials may pass through a scrubbing apparatus, but the scrubbing process has varying efficiencies and these materials may not be 100% washed away.For example, Beu et al. (Reduction of Perfluorocompound (PFC) Emissions: 2005 State-of-the-Technology Report. International SEMATECH Manufacturing Initiative Technology Transfer #05104693A-ENG) reported a wide range of decomposition efficiencies of emission reduction systems commonly used in the semiconductor industry. Emissions from etching processes can be characterized and quantified using QMS and FTIR along with other measurement methods. Emissions from etching processes can be mitigated using various emission reduction processes, including plasma, thermal combustion processes (e.g., using CH4), adsorption processes, water neutralization, and catalytic reactions. Additives (such as O2, H2O, O3, etc.) can be added to etching emissions to react with them and further reduce their GWP. For example, by oxidizing carbonaceous materials to CO, CO2, and COF2.

[0049] According to Kopylov et al. in "Characteristics of Impact on the Atmosphere of Perfluorisohexenes - Promising Components of Gas Extinguishing Compositions", acyclic C6F12 is particularly attractive due to its very low GWP of about 30 (due to the incorporation of C=C double bonds), while other conventional etching gases have very high GWPs, such as C4F8 with a GWP of 9540. Furthermore, according to Simmonds et al. in "The background atmospheric concentrations of cyclic perfluorocarbon tracers determined by negative ion-chemical ionization mass spectrometry", cyclic C6F12 is expected to have a high GWP of approximately 10,000. This paper discloses the use of C6F12 as the sole fluorocarbon gas or in combination with other fluorocarbon or hydrofluorocarbon etching gases for selective etching of SiO2 and SiN layers relative to a masking material such as aC. For example, when mixed with C6F12, the addition of a hydrofluorocarbon gas system with low GWP (such as C2H2F2) is particularly beneficial. The addition of a hydrofluorocarbon gas facilitates the etching of the SiN layer and provides a polymerizing gas for selective etching relative to the aC masking material. Conventional etching gases include octafluorocyclobutane (cC4F8), hexafluoro-1,3-butadiene (C4F6), CF4, CH2F2, CH3F, and / or CHF3. It is well known that selectivity and polymer deposition rate increase with increasing C:F ratio (i.e., C4F6 > C4F8 > CF4). See, for example, US 6387287 granted to Hung et al. However, the C:F ratio may not directly predict etching performance. Anderson et al. (US 2015294880) taught that the C:F ratio of the etching gas does not directly correspond to the C:F ratio in the deposited polymer. For example, molecules with the same chemical formula but different structures may produce polymers with different C:F ratios, different deposition rates, different fragments (as measured by mass spectrometry), and different etching rates and selectivity for various materials (SiO2, aC, photoresist, SiN).For etching applications with very high aspect ratios, such as >20:1 applications like 3D NAND or DRAM, they may not offer sufficient performance. The -CxFy polymer on the sidewalls may be readily etched by ion bombardment and reaction with F* in the Si material. As a result, the etched pattern may not be vertical, and the etched structure may exhibit bending, dimensional variations, pattern collapse, and / or increased roughness. Temperature is a critical parameter in the etching process. High aspect ratio plasma etching is extremely challenging. A new emerging technology uses very low substrate temperatures; these are typically below -20°C, while traditional etching chambers are limited to around -70°C. In this case, much less polymer gas is required, thus accelerating etching and allowing for good profile control, as the etching byproducts themselves act as sidewall protectors. Etching profiles can be controlled at lower temperatures by limiting volatile byproducts (i.e., SiF4 is volatile above -86°C, CO2 is volatile above -70°C, and other etching byproducts are not volatile at these temperatures), resulting in a highly vertical etch profile. On the other hand, temperature affects the adhesion coefficient of free radicals, thus influencing polymerization, etching rate, and selectivity. Both cryogenic and hyperthermic etching are important processes in semiconductor etching. For example, wafer temperatures up to 60°C are commonly used in dielectric etching processes. Chamber pressure affects the residence time of different substances within the chamber and the number of molecules / free radicals / ions in the chamber. Pressure is closely related to the etching rate, selectivity, and profile in patterning etching processes. Typical ranges are from 1 mTorr to 500 mTorr.

[0050] Molecules having the formula C6F12 are preferably acyclic compounds containing double bonds, as listed in Table 2. The most preferred C6F12 series are CAS numbers 2070-70-4 and 3709-71-5. [Table 2.] Acyclic isomers of C6F12 containing double bonds name CAS# Molecular structure Perfluoro-4-methyl-2-pentene 2070-70-4 Perfluoro-2-methyl-2-pentene 1584-03-8 Perfluorohex-1-ene 755-25-9 Perfluorohexene-2 1584-00-5 Tetra(trifluoromethyl)ethylene 360-57-6 1,1,1,2,2,3,4,5,5,6,6,6-Dodecano-3-hexene 1584-02-7 trans-4-(trifluoromethyl)perfluoro-2-pentene 3709-71-5 Perfluorohexene-2 1584-00-5 trans-perfluoro-4-methylpent-2-ene 3709-70-4 Nonafluoro-2-(trifluoromethyl)-1-pentene 359-72-8 1,1,1,2,4,4,5,5,5-Nonafluoro-3-(trifluoromethyl)-2-pentene 67483-02-7 Perfluorohexene-2 67899-37-0 1,1,2,4,4,4-Hexafluoro-3,3-bis(trifluoromethyl)-1-butene 137202-54-1 (3E)-1,1,1,2,2,3,4,5,5,6,6,6-dodecano-3-hexene 81018-66-8 (2E)-1,1,1,2,4,4,5,5,5-Nonafluoro-3-(trifluoromethyl)-2-pentene 87743-93-9 1,1,2,3,3,4,5,5,5-Nonafluoro-4-(trifluoromethyl)-1-pentene 287101-12-6 (Z)-1,1,1,2,4,4,5,5,5-Nonafluoro-3-(trifluoromethyl)-2-pentene 87744-03-4 (Z)-1,1,1,2,2,3,4,5,5,6,6,6-dodecano-3-hexene 71186-98-6 (Z)-1,1,1,2,3,4,4,5,5,6,6,6-dodecano-2-hexene 71186-97-5 1,1,1,4,4,4-Hexafluoro-2,3-bis(trifluoromethyl)-2-butene, 66319-89-9 1,1,3,4,4,4-Hexafluoro-2,3-bis(trifluoromethyl)-1-butene 58621-70-8 3-(difluoromethylene)-1,1,1,2,2,4,4,5,5,5-decafluoropentane 873536-26-6 1,1,2,3,3,3-Hexafluoro-1-propylene dimer 13429-24-8 [Table 3.] Cyclic isomers of C6F12 that may have high GWP and do not contain double bonds. name CAS number structure Boiling point (°C) Perfluoro(methylcyclopentane) 1805-22-7 48 Perfluoro-1,2-dimethylcyclobutane 2994-71-0 45 perfluorocyclohexane 355-68-0 59-60

[0051] Considering the examples of hydrofluorocarbon etching compounds and their isomers listed in Table 2 and the studies described in the following examples, it can be concluded that the vapor of non-cyclic C6F12 with C=C double bonds can be used as an etching gas with very low GWP100 for plasma etching processes, especially any non-cyclic C6F12 with C=C double bonds included in Table 2, most preferably C6F12 with CAS numbers CAS 2070-70-4 and CAS 3709-71-5.

[0052] The PFC and HFC etching gases with very low GWP100 disclosed include acyclic C6F12 and its isomers used in etching processes and / or in chamber conditioning processes, preferably acyclic C6F12 (CAS No.: 2070-70-4 and CAS No. 3709-71-5).

[0053] The disclosed non-annular C6F12 (CAS No.: 2070-70-4 and CAS No. 3709-71-5) can be used in etching processes and / or in chamber conditioning processes.

[0054] During the etching process, the temperature range of the substrate can be from -196°C to 300°C, preferably from -20°C to 150°C. The substrate can be cooled by a variety of sources, including commercially available coolers or other methods (such as liquid N2).

[0055] The reaction chamber wall temperature can be approximately >20°C, preferably <50°C. Depending on the process requirements, the reaction chamber wall temperature can be approximately room temperature or higher but less than 50°C.

[0056] For a typical dielectric etching process, the pressure in the reaction chamber can range from 1 millitor to 10,000 millitor.

[0057] One or more hydrofluorocarbons or fluorocarbon etching gases that may be added to the non-cyclic C6F12 are selected from C4F6, C4F8, C4H2F6, CHF3, CH2F2, CH3F, CF4, C2F6, C3F8, SF6, NF3, C2F4, C3F6, C4F10, C5F8, C6F6, C1-C7CxFy molecules (x and y are integers), C2H2F2, C2H5F, C3H7F, C3H2F6, C2HF5, C1-C7CxFyHz molecules (where x, y, and z are integers), or combinations thereof; preferably C2H2F2.

[0058] Plasma can be generated using RF power ranging from about 1 W to about 100,000 W. Plasma can be generated remotely or within the reactor itself. The RF frequency of the plasma can range from 40 kHz to 1 GHz.

[0059] An etching process using non-cyclic C6F12 may include the step of sequentially or simultaneously exposing the substrate to co-reactants and / or additives prior to activating the plasma.

[0060] Other gases, acting as co-reactants and / or additives, may be added to the acyclic C6F12. These other gases include H2, SF6, NF3, NH3, Cl2, BCl3, BF3, Br2, F2, FNO, FNO3, HBr, HCl, HI, IF5, IF7, B2H6, HF, and P-containing gases selected from PF3, PCl3, PBr3, PH3, POCl3, PF5, POF3, PH3PCl5, PBr5, PF2BrO, PCl3O, PF2Br, or PR3 (where R is an alkyl group or a fluorinated alkyl group). An example PR3 is P(CF3)3.

[0061] Other gases may also include inert gases selected from the following: Ar, Kr, Xe, Ne, N2, He or combinations thereof.

[0062] Other gases used to add to non-cyclic C6F12 may include O2, CO, CO2, NO, NO2, N2O, SO2, H2S, COS, O3, OF2, SOF2, SO2F2, CxOyFzSmHn (where x, y, z, m and n are integers) such as (CF3SO2)2O or CF4SO2, CxOyFzNmHn (where x, y, z, m and n are integers) such as CF3N=O, or CxOyFz such as COF2 or C2O2F2, CxOyFzHm (where x, y, z and m are integers) such as alcohols, ketones, acids, or esters selected from CF3OH, CF3OCF3, (CF3)2C=O, CF3COOH or combinations thereof.

[0063] The reaction chamber can be any accessory or chamber within the apparatus in which the etching method is performed, such as, but not limited to, reactive ion etching (RIE), CCP with a single or multiple frequency RF sources, inductively coupled plasma (ICP), or microwave plasma reactor, or other types of etching systems capable of selectively removing a portion of a silicon-containing film, or generating active material, or depositing a film.

[0064] The substrate can be any of the following materials containing Si, such as Si, SiO2, SiN, SiOC, SiC, SiCN, or doped with boron, phosphorus, and any metal. An example is a multilayer of SiO and SiN used in 3D NAND applications.

[0065] The masking material used in this article may be amorphous carbon (aC) or doped amorphous carbon, or Si or SiN, Al, AlO, Ti, TiO, TiN, AlN, and other metal, metal oxide masking, silicon oxide masking, metal nitride and silicon nitride masking.

[0066] During the etching process, if the temperature of the substrate is cooled to a low temperature, the etched substrate is heated, for example, the etched substrate is heated to > -70°C, so that when etching is performed at a low temperature (< -70°C), the byproducts of the etching reaction are evaporated and enter the vacuum leaving the chamber.

[0067] C6F12 not only has a much lower GWP than standard fluorinated compound etching gases, but also produces lower CO2 equivalent emissions from the etching process. The disclosed plasma etching method uses C6F12 as the etching gas to create pores in silicon-containing films, such as channel holes, gate trenches, stepped contacts, capacitor holes, contact holes, contact etching, slot etching, self-aligned contacts, self-aligned vias, supervias, etc. The resulting pores can have an aspect ratio ranging from about 5:1 to about 500:1, preferably from about 20:1 to about 400:1. The resulting pores can have a diameter ranging from about 0.1 nm to about 500 nm; preferably, from about 0.1 nm to about 500 nm; more preferably, less than 100 nm. The resulting vias can have an aspect ratio greater than 1:1, preferably greater than 5:1, more preferably greater than 10:1, and even more preferably greater than 20:1. The resulting vias can have an aspect ratio ranging from 1:1 to 5:1. For example, those skilled in the art will recognize that channel hole etching in a silicon-containing film produces vias with an aspect ratio greater than 50:1.

[0068] A method for reducing CO2eq emissions from etching processes used to etch silicon-containing layers is disclosed. Emissions from the etching process can be characterized and quantified using QMS and FTIR along with other measurement methods. Emissions from the etching process can be mitigated using various emission reduction processes, including plasma, thermal combustion processes (e.g., using CH4), adsorption processes, water neutralization, and catalytic reactions. Additives (such as O2, H2O, O3, etc.) can be added to the etching emissions to react with them and further reduce their GWP (e.g., by oxidizing carbonaceous material to CO, CO2, and COF2) or to make the emissions easier to reduce (e.g., by using H2O to convert F2 to HF).

[0069] The disclosed acyclic C6F12 (e.g., CAS No.: 2070-70-4) can be supplied in various fill volumes, pressures, and specifications in gas cylinders, steel cans, bubblers, or similar suitable packaging. Since C6F12 (boiling point 49°C) is a liquid, it can be delivered to the etching chamber in the gas phase or as a liquid phase to the vaporizer. Preferably, the material has a low moisture content of <40 ppm, more preferably <10 ppm. C6F12 can be purified by distillation, adsorption using molecular sieves, or other common and known methods in the art to remove critical impurities such as other fluorocarbons, hydrofluorocarbons, chlorofluorocarbons (CFCs), impurities from the air (N2, O2, CO2), moisture (H2O), HF, other hydrocarbons (CH4, etc.). Some impurities can form azeotropes; therefore, other purification methods may be required to separate them using chemical means. Examples

[0070] A more detailed description of the disclosed method is provided below by way of example. However, the disclosed method is not limited in any way to the examples presented, and the process conditions, process gas mixtures, the combination and proportion of gases in the gas mixtures, the workpiece, and the plasma etching chamber itself may be varied.

[0071] In the following examples, the primary plasma etching source may be CCP plasma, but other sources such as ICP, microwave, ECR, etc. may also be included. The plasma may be used as a continuous source or as a pulsed plasma with a specific frequency and duty cycle. The temperature of the substrate surface may be cooled or raised by a cooler, or by a liquid N2 supply and heating stage. Additional fluorocarbon gases may be added to slightly adjust the etching performance. Additional inert gases such as Kr, Xe, Ne, and hydrogen source gases such as H2, as well as hydrocarbons, may be added. The masking material may include TiN or other metal nitride materials, SiN, Si, carbon materials, etc. In the following examples, for comparative purposes, the etching and emission performance of CH2F2 and C4H2F6 disclosed in US 2023 / 0127467 are also presented. The examples were performed in a 300 mm CCP plasma etcher. All reported CO2eq emissions are normalized to the SiO2 etching rate (unless otherwise stated) and are before emission reduction. In all experiments, the RF source power was 950 / 200 W and the bias power was 6000 / 200 W (meaning the power cycled between high and low power at a given frequency). All etching experiments using C6F12 were on the CAS#2070-70-4 isomer.

[0072] Example 1 compares the etching rates of three common materials used in semiconductor processing, SiO2, SiN, and aC, under the process conditions described in Table 4 below. As can be seen from the results in Figure 1, C6F12 has a significantly higher SiO2 etching rate than C4F8 and C4F6, and the selectivity for aC is 4.5 (C6F12), 5.5 (C4F6), and 2.0 (C4F8). This is unexpected since both C4F8 and C6F12 have the same C / F ratio (C / F = 0.5). C4F6, with two double bonds, has a lower SiO2 etching rate than C6F12, but slightly higher selectivity due to its lower aC etching rate. [Table 4] HAR Channel hole etching C4F8 C4F6 C6F 12 Pressure [millitor] twenty two twenty two twenty two C4F8 flow rate (FR) [sccm] 20 0 0 C4F6FR [sccm] 0 20 0 C6F 12 FR [sccm] 0 0 20 O2FR [sccm] 40 40 40 Ar FR [sccm] 150 150 150 Wafer T [°C] 20 20 20

[0073] Example 2: Using the same process conditions as in Example 1, CO2eq emissions from the plasma etching chamber were measured using FTIR and the results were normalized to the SiO2 etching rate, and then compared with CO2eq emissions of C4F8. It was found that the CO2eq emission coefficients of C4F6 and C6F12 were similar, but the emission coefficient of C4F8 was significantly higher, as shown in Figure 2.

[0074] Example 3 In a plasma etching chamber, under similar conditions described in Table 5 below, C4F8, C4F6, or C6F12 were individually mixed with hydrofluorocarbon gas CH2F2 along with O2 and Ar, and their etching rates for SiO2, SiN, and aC were compared. The addition of hydrogen-containing gases can be used to etch SiN layers, as in 3D NAND SiO2 / SiN etching processes. As can be seen in Figure 3, the formulation containing C6F12 exhibits a higher SiO2 etching rate than the other gases, demonstrating a significant amount-based benefit. The selectivity for aC is C4F8 = 4.4, C4F6 = 13.5, and C6F12 = 6.8. This shows that C6F12 maintains higher selectivity compared to C4F8, but is still lower than C4F6 due to the two double bonds in C4F6. Therefore, although C6F12+ CH2F2 offers etching benefits compared to C4F8+ CH2F2, its selectivity remains lower than that of C4F6. Furthermore, the combination of C6F12+ CH2F2 unexpectedly provides a higher SiN etch rate compared to C4F6+ CH2F2, which may be beneficial for SiO / SiN alternating layer etching processes. [Table 5] HAR Channel hole etching C4F8+ CH2F2 C4F6+ CH2F2 C6F 12 + CH2F2 Pressure [millitor] twenty two twenty two twenty two C4F8FR [sccm] 20 0 0 C4F6FR [sccm] 0 20 0 CH2F2FR [sccm] 20 20 20 C6F12 FR [sccm] 0 0 20 O2FR [sccm] 40 40 40 Ar FR [sccm] 150 150 150 Wafer T [°C] 20 20 20

[0075] Example 4 compares normalized CO2eq emissions relative to C4F8 + CH2F2 under the same conditions. As can be seen from Figure 4, the addition of CH2F2 did not change the order of CO2eq emissions from individual gases, with the C4F8 process being much larger than the C6F12 process, and the C4F6 process being slightly smaller. The CO2eq emissions of the C6F12 process are 30% lower than those of the equivalent C4F8 process.

[0076] Example 5 Similar to Examples 3 and 4, the same gas was mixed with C2H2F2 (CAS# 75-38-7) instead of CH2F2 under the conditions described in Table 6 below. It should be noted that the flow rate (FR) of C2H2F2 is half that of CH2F2, but provides the same molar amount of carbon in this process. The etching rate and emission results are shown in Figures 5 and 6, respectively. The SiO2 / aC selectivity is as follows: C6F12: 20; C4F6: 18.8; C4F8: 4.5. Surprisingly, the combination of C6F12 and C2H2F2 gives a higher SiO2 etching rate and higher SiO2 / aC selectivity than C4F8 or C4F6, which is highly beneficial for this etching process. This differs from the results compared to CH2F2 (where the selectivity trend did not change when added to each individual gas). Therefore, compared with other etching gas combinations, the combination of C6F12 + C2H2F2 showed unexpectedly improved etching performance. [Table 6] HAR Channel hole etching C4F8+ C2H2F2 C4F6+ C2H2F2 C6F 12 + C2H2F2 Pressure [millitor] twenty two twenty two twenty two C4F8FR [sccm] 20 0 0 C4F6FR [sccm] 0 20 0 C2H2F2FR [sccm] 10 10 10 C6F 12 FR [sccm] 0 0 20 O2FR [sccm] 40 40 40 Ar FR [sccm] 150 150 150 Wafer T [°C] 20 20 20

[0077] Example 6: Normalized CO2eq emissions were measured for the etching processes shown in Example 5 and Figure 6, and are listed below relative to the C4F8+C2H2F2 emission treatment. CO2eq emissions from minimum to maximum are C6F12+C2H2F2 < C4F6+C2H2F2 << C4F8+C2H2F2. Although C6F12 has a slightly higher GWP than C4F6, it gives even lower normalized CO2eq emissions when combined with C2H2F2, which is a significant improvement. This is an unexpected result that the combination of the two gases C6F12+C2H2F2 provides a significant benefit to etching performance and CO2eq emissions. Furthermore, C6F12+C2H2F2 gives a higher SiN etching rate than C4F6+C2H2F2, which may be beneficial for SiO / SiN etching processes (such as those used in 3D NAND).

[0078] Example 7: The QMS of C6F12 was compared with the QMS of C4F8, C4F6, and C4H2F6 (CAS#: 382-10-5) disclosed in US 9514959. The QMS composition at 26 eV, as a percentage of total matter, is shown in Figure 7 (C6F12 CAS#: 2070-70-4), Figure 8 (C4H2F6), Figure 9 (C4F8), and Figure 10 (C4F6), and the primary substances (major and minor substances) are listed in Table 7 below. As can be seen from the results, both C6F12 and C4H2F6 produce CF3 as primary substances. However, C6F12 and C4F6 produce different substances, although both have double bonds and are fully fluorinated molecules. C6F12 and C4F8 have the same minor substances and are both fully fluorinated molecules. Therefore, these QMS formulations with different formulations can be compared with the emissions, and it should be noted that, despite the similarity of the molecules, C6F12 yields unexpected and undesirable results in terms of emissions and emissions GWP. Etching rates and selectivity can also be compared, and it should be noted that, despite their similar QMS composition, C6F12 exhibits surprisingly better etch rates and selectivity compared to both C4F8 and C4H2F6. [Table 7] molecular QMS main substances QMS secondary substances C6F 12 CF3 C3F5 C4H2F6 CF3 C3F3H2 C4F6 C3F3 CF C4F8 C2F4 C3F5

[0079] Example 8 The SiO2 etching rates of C4F8, C6F12, and C4H2F6 were compared under similar conditions as shown in Table 8 below, and are shown in Table 9 (relative to a process treatment containing C4F8). As can be seen from the results, C6F12 exhibits a surprisingly higher SiO2 etching rate (1.6x) compared to C4H2F6, although both produce similar primary ions (CF3) in the QMS. Compared to C4F8, C6F12 also exhibits a much higher etching rate (2.8x) while having similar secondary ions (C3F5) in the QMS. Also surprisingly, the CO2eq emissions of the C6F12 formulation are much lower than those of C4F8 or C4H2F6. Although C4H2F6 (GWP100 = 4) has a lower GWP than C6F12 (GWP100 = 30) and similar primary QMS materials (CF3), it has higher CO2eq emissions from the plasma etching process, as shown in Table 9. [Table 8] Plasma etching C4F8 formula C4H2F6 formula C6F 12 formula Pressure [millitor] 15 15 15 C4F8FR [sccm] 20 0 0 C4H2F6FR [sccm] 0 0 20 C6F 12 FR [sccm] 0 20 0 O2FR [sccm] 40 40 40 Ar FR [sccm] 150 150 150 Wafer T [°C] 60 60 60 [Table 9] C4F8 formula C4H2F6 formula C6F 12 formula Relative SiO2 etching rate 1.0 1.6 2.8 relative to CO 2eq emission 1.0 0.4 0.2

[0080] As the results show, the molecular structure, QMS decomposition substances, C / F ratio and GWP of etched molecules are insufficient to predict both SiO2 etching rate and CO2eq emissions of the etching process.

[0081] Example 9 Using the process conditions described in Table 10 below, plasma etching emissions from a 300 mm CCP plasma etching tool were measured using FTIR to compare emissions from C4H2F6+C4F6+CH2F2, C4H2F6+C4F6+C2H2F2, C6F12+C4F6+CH2F2, and C6F12+C4F6+C2H2F2. These formulations can be used for high aspect ratio etching applications, such as SiO2 / SiN alternating layers in 3D NAND. Since both C4H2F6 and C6F12 have similar primary materials (CF3) in QMS, their CO2eq emissions are expected to be similar. In this example, CO2eq emissions are not normalized to the SiO2 etching rate but are relative to the corresponding CO2eq emission treatment of the C4H2F6 formulation. As can be seen from the results shown in Table 11, the combination of C6F12 and CH2F2 has 11% lower CO2eq emissions compared to C4H2F6 and CH2F2. However, as shown in Table 12, adding C2H2F2 instead of CH2F2 to these formulations resulted in a 35% reduction in CO2eq emissions for the C6F12 formulation compared to the C4H2F6 formulation. Therefore, it is clear that the GWP of the individual gases cannot predict the CO2eq of the etching process, as C6F12 shows environmental benefits compared to C4H2F6, but has a higher GWP (30 vs. 4) (this means that the inherent GWP value of C6F12 = 30, while the GWP of C4H2F6 = 4), and when combined with C2H2F2, it leads to a significant reduction in CO2eq emissions. [Table 10] Plasma etching C4H2F6+ C4F6+ CH2F2 C4H2F6+ C4F6+ C2H2F2 C6F 12 + C4F6+ CH2F2 C6F 12 + C4F6+ C2H2F2 Pressure [millitor] twenty two twenty two twenty two twenty two C4F6FR [sccm] 17 17 17 17 CH2F2 gas [sccm] twenty one 0 twenty one 0 C4H2F6FR [sccm] 18 18 0 0 C6F 12 FR [sccm] 0 0 17 17 C2H2F2FR [sccm] 0 10 0 10 O2FR [sccm] 33 32 28 28 Ar FR [sccm] 150 150 150 150 Wafer T [°C] 20 20 20 20 [Table 11] C4H2F6+ C4F6+ CH2F2 C6F 12 + C4F6+ CH2F2 relative to CO 2eq emission 1.00 0.89 [Table 12] C4H2F6+ C4F6+ C2H2F2 C6F 12 + C4F6+ C2H2F2 relative to CO 2eq emission 1.00 0.67

[0082] It should be understood that those skilled in the art can make many additional changes to the details, materials, steps, and arrangements of parts that have been described and elucidated to explain the nature of the invention as set forth in the appended claims, within the principles and scope of the invention. Therefore, the invention is not intended to be limited to the specific embodiments given above and / or in the accompanying drawings.

[0083] 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 restrictive. Many variations and modifications of the components 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. [Simplified Explanation of the Diagram]

[0046] 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 wherein: [Figure 1] is a bar graph comparing the etching rates of C6F12, C4F8, and C4F6 of common materials aC, SiO2, and SiN used in semiconductor processing, respectively; [Figure 2] is a bar graph measuring CO2 equivalent emissions (before emission reduction) from the plasma etching chamber using FTIR under the same process conditions as in Figure 1, and normalizing the results for SiO2 etching rate; [Figure 3] is a bar graph comparing the etching rates of C6F12, C4F8, and C4F6 of aC, SiO2, and SiN, respectively (each individually mixed with hydrofluorocarbon gas CH2F2 along with O2 and Ar); [Figure 4] is a bar graph of normalized CO2 equivalent emissions under the same conditions as in Figure 3; [Figure 5] is a bar graph comparing the etching rates of C6F12, C4F8, and C4F6 (each individually mixed with hydrofluorocarbon gas C2H2F2 along with O2 and Ar) applied to aC, SiO2, and SiN, respectively; [Figure 6] is a bar graph of normalized CO2 equivalent emissions under the same conditions as Figure 5; [Figure 7] is a pie chart of QMS for C6F12 CAS #: 2070-70-4; [Figure 8] is a pie chart of QMS for C4H2F6; [Figure 9] is a pie chart of QMS for C4F8; and [Figure 10] is a pie chart of QMS for C4F6. [Biomaterial Storage]

[0085] None

Claims

1. An etching method for forming a hole in a substrate, the method comprising: The substrate is exposed to an etching gas containing a non-cyclic C6F12, wherein the temperature of the substrate is in the range of approximately -196°C to approximately 300°C; the etching gas is converted into a plasma; an etching reaction is allowed between the plasma and one or more silicon-containing films contained in the substrate, such that the one or more silicon-containing films are selectively etched relative to a patterned mask layer deposited on the one or more silicon-containing films to form the aperture therein and form volatile byproducts; and the volatile byproducts are removed.

2. The method as described in claim 1, further comprising adding one or more hydrofluorocarbon or fluorocarbon etching gases to the etching gas, wherein the one or more hydrofluorocarbon or fluorocarbon etching gases are selected from C4F6, C4F8, C4H2F6, CHF3, CH2F2, CH3F, CF4, C2F6, C3F8, SF6, NF3, C2F4, C3F6, C4F10, C5F8, C6F6, C1-C7 CxFy molecules (x and y are integers), C2H2F2, C2H5F, C3H7F, C3H2F6, C2HF5, C1-C7 CxFyHz molecules (where x, y, and z are integers), or combinations thereof.

3. The method as described in claim 1, further comprising adding C2H2F2 to the etching gas.

4. The method as described in claim 1, further comprising adding a P-containing gas, such as H2, SF6, NF3, NH3, Cl2, BCl3, BF3, Br2, F2, FNO, FNO3, HBr, HCl, HI, IF5, IF7, HF, B2H6, or selected from PF3, PCl3, PBr3, PH3, POCl3, PF5, POF3, PH3, PCl5, PBr5, PF2BrO, PCl3O, PF2Br, or PR3—wherein an R-series alkyl or fluorinated alkyl—to the etching gas.

5. The method as described in claim 1, further comprising adding O2, CO, CO2, NO, NO2, N2O, SO2, H2S, COS, O3, OF2, SOF2, SO2F2, CxOyFzSmHn selected from (CF3SO2)2O or CF4SO2 (where x, y, z, m and n are integers), CxOyFzNmHn selected from CF3N=O (where x, y, z, m and n are integers), or CxOyFz selected from COF2 or C2O2F2, or CxOyFzHm selected from alcohols, ketones, acids, esters, or combinations thereof (where x, y, z and m are integers) selected from CF3OH, CF3OCF3, (CF3)2C=O, CF3COOH, or combinations thereof to the etching gas.

6. The method as described in claim 1, further comprising adding an inert gas to the etching gas, wherein the inert gas is selected from Ar, Kr, Xe, Ne, N2, He, or combinations thereof.

7. The method as described in any one of claims 1 to 6, wherein, This acyclic C6F12 is an isomer of C6F12 with the following CAS numbers: 2070-70-4, 1584-03-8, 755-25-9, 1584-00-5, 360-57-6, 1584-02-7, 3709-71-5, 1584-00-5, 3709-70-4, 359-72-8, 67483-02-7 67899-37-0, 137202-54-1, 81018-66-8, 87743-93-9, 287101-12-6, 87744-03-4, 71186-98-6, 71186-97-5, 66319-89-9, 58621-70-8, 873536-26-6, or 13429-24-8.

8. The method as described in any one of claims 1 to 6, wherein, This acyclic C6F12 is an isomer of C6F12 with the following CAS number: 2070-70-4.

9. The method as described in any one of claims 1 to 6, wherein, This acyclic C6F12 is an isomer of C6F12 with the following CAS number: 3709-71-5.

10. The method as described in any one of claims 1 to 6, wherein, The temperature range of this substrate is approximately -196°C to approximately 60°C.

11. The method as described in any one of claims 1 to 6, wherein, The temperature of this substrate is below approximately -20°C.

12. The method as described in any one of claims 1 to 6, wherein, The temperature range of this substrate is approximately -196°C to approximately -50°C.

13. The method as described in any one of claims 1 to 6, wherein, After the hole is formed, the temperature of the substrate is raised to greater than -70°C.

14. The method as described in any one of claims 1 to 6, wherein, Compared to an etching process using an etching gas with GWP100 > 30, the CO2eq emissions of these volatile byproducts are reduced.

15. An etching method for forming a hole in a substrate, the method comprising: The substrate is maintained at a temperature ranging from approximately -196°C to approximately 300°C; The substrate is exposed to an etching gas containing a non-annular C6F12 (CAS No.: 2070-70-4 or CAS No.: 3709-71-5) entering a reaction chamber; C2H2F2 is added to the etching gas; the etching gas is converted into a plasma; an etching reaction is allowed between the plasma and one or more silicon-containing films contained in the substrate, such that the one or more silicon-containing films are selectively etched relative to a patterned mask layer deposited on the one or more silicon-containing films to form the aperture therein; And the removal of volatile byproducts.

16. The method as described in claim 15, further comprising adding a phosphorus-containing gas and an HF-containing gas.

17. The method as described in claim 15, further comprising adding a fluorocarbon or hydrofluorocarbon gas, an oxidizing gas, and an inert gas.

18. The method as described in any of claims 15 and 17, wherein, Compared to etching processes using etching gases with GWP100 > 30, CO2eq emissions of these volatile byproducts are reduced.

19. An etching method for forming a hole in a substrate, the method comprising: The substrate is maintained at a temperature ranging from approximately -196°C to approximately 300°C; The substrate is exposed to an etching gas containing a non-annular C6F12 (CAS No.: 2070-70-4) entering a reaction chamber; C2H2F2 is added to the etching gas; the etching gas is converted into a plasma; an etching reaction is allowed between the plasma and one or more silicon-containing films contained in the substrate, such that the one or more silicon-containing films are selectively etched relative to a patterned masking layer deposited on the one or more silicon-containing films to form the aperture therein; And the removal of volatile byproducts.

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