Etching gas containing hexafluoro-2-butyne

Abstract

The purpose of the present disclosure is to provide an etching gas containing hexafluoro-2-butyne. The etching gas contains hexafluoro-2-butyne.

Description

Etching gas containing hexafluoro-2-butyne

[0001] This disclosure relates to an etching gas containing hexafluoro-2-butyne.

[0002] Patent Document 1 discloses a method for producing a perfluoroalkyne compound, which includes the step of reacting a perfluoroalkadiene compound in the presence of a catalyst to obtain a perfluoroalkyne compound; a composition containing a perfluoroalkyne compound and a perfluorocycloalkene compound; a catalyst used for reacting a perfluoroalkadiene compound to obtain a perfluoroalkyne compound; and a method for producing a catalyst used for reacting a perfluoroalkadiene compound to obtain a perfluoroalkyne compound.

[0003] Patent Document 2 discloses a method for producing a halogenated butene compound, which includes a step of dehydrofluorinating a halogenated butene compound; a method for producing a halogenated butyne compound, which includes a step of dehydrofluorinating a halogenated butene compound; and a method for producing a halogenated butyne compound, which includes a step of producing a halogenated butene compound by dehydrofluorinating a halogenated butene compound, and then producing a halogenated butyne compound by dehydrohalogenating the halogenated butene compound.

[0004] Patent Document 3 discloses a method for producing a perfluorocarbon compound, comprising the step of reacting a halogenated hydrocarbon compound in an organic solvent in the presence of an iodine-containing inorganic material and zinc or a zinc alloy to obtain a perfluorocarbon compound, and a method for producing a perfluoroalkyne compound, comprising the step of reacting a halogenated alkene compound in the presence of zinc or a zinc alloy in at least one nitrogen-containing polar organic solvent selected from the group consisting of N,N-dimethylacetamide, N,N-diisopropylformamide, N-methyl-2-pyrrolidone, 1,3-dimethyl-3,4,5,6-tetrahydropyrimidinone, hexamethylphosphate triamide, amine compounds, pyridine compounds, and quinoline compounds to obtain a perfluoroalkyne compound.

[0005] International Publication Number WO2020 / 075728A1 International Publication Number WO2020 / 171011A1 International Publication Number WO2020 / 204146A1

[0006] This disclosure aims to provide a new etching gas containing hexafluoro-2-butyne.

[0007] This disclosure includes the following components:

[0008] Item 1. An etching gas comprising: (1) 1,1,1,4,4,4-hexafluoro-2-butyne (CF3C≡CCF3); and (2) at least one component selected from the group consisting of (2-1) metal elements in the third period and metal elements in the fourth period; and (2-2) compounds having 2 or 3 carbon atoms and possessing one double or triple bond.

[0009] Item 2. The etching gas according to Item 1, wherein, with respect to the total amount of etching gas, the content of (1) 1,1,1,4,4,4-hexafluoro-2-butyne is 99% by volume or more and 99.9995% by volume or less, and (2) when the composition contains (2-1) the metal element, the content of the metal element is 0.5 ppb by mass or more and 40 ppb by mass or less, or when the composition contains (2-2) the compound, the content of the compound is 0.5 ppm by volume or more and 95 ppm by volume or less.

[0010] Item 3. The etching gas according to Item 1, wherein the metal element in the third period is at least one metal element selected from the group consisting of sodium (Na), magnesium (Mg), and aluminum (Al), and the metal element in the fourth period is at least one metal element selected from the group consisting of calcium (Ca) and iron (Fe).

[0011] Item 4. The etching gas according to Item 1, wherein the compound is at least one halogenated alkene compound selected from the group consisting of halogenated ethylene compounds represented by the formula CF2=CFX (wherein X represents a hydrogen atom (H), a chlorine atom (Cl), a bromine atom (Br), or an iodine atom (I)) and hexafluoropropene (CF3-CF=CF2).

[0012] Item 5. The etching gas according to Item 1, wherein the compound is a halogenated alkyne compound represented by the formula CF3C≡CX (wherein X represents a hydrogen atom (H), a chlorine atom (Cl), a bromine atom (Br), or an iodine atom (I)).

[0013] Item 6. The etching gas according to Item 1, wherein the composition contains (2) (2-1) the metal element, and further contains (3) water, and in the etching gas, the content of (3) water relative to the total amount of etching gas is 0.1 volume ppm or more and 20 volume ppm or less.

[0014] Item 7. An etching method for etching a silicon-based material on which a silicon oxide film or silicon nitride film is formed, using a gas plasma of the etching gas (A) described in any one of claims 1 to 6.

[0015] Item 8. The etching method according to Item 7, wherein the silicon-based material is a substrate for semiconductor manufacturing.

[0016] Item 9. The etching method according to Item 7, wherein (A) the etching gas and (B) the inert gas are supplied separately and continuously to generate an etching mixed gas in a chamber, and a silicon-based material is etched.

[0017] Item 10. The etching method according to Item 7, wherein (A) the etching gas and (C) the oxidizing gas and / or reducing gas are supplied separately and continuously to generate an etching mixed gas in a chamber, and a silicon-based material is etched.

[0018] Item 11. The etching method according to Item 7, wherein (A) etching gas, (B) inert gas, and (C) oxidizing gas and / or reducing gas are supplied separately and continuously to generate an etching mixed gas in a chamber, and a silicon-based material is etched.

[0019] This disclosure discloses an etching gas containing hexafluoro-2-butyne (CF3C≡CCF3). According to this disclosure, an etching gas containing hexafluoro-2-butyne can be used to etch silicon oxide films (SiO2 films), silicon nitride films (SiN films), or silicon-based materials containing photoresist (PR, etching mask) materials by containing at least one metal element selected from the group consisting of metal elements in the third period and metal elements in the fourth period, or by containing a compound having 2 or 3 carbon atoms and having one double or triple bond (halogenated alkene compounds (olefin compounds), and halogenated alkyne compounds).

[0020] The etching gas containing hexafluoro-2-butyne of this disclosure, in particular, by adjusting the content of metal elements to 40 mass ppb or less, has an appropriate metal concentration, suppresses the inclusion of metal in the formed deposited film, maintains an appropriate hardness in the deposited film, maintains an appropriate etching rate for the amorphous carbon layer (ACL), and exhibits good selectivity for SiO2 film / ACL or SiN film / ACL.

[0021] The etching gas containing hexafluoro-2-butyne of this disclosure has an appropriate metal concentration, the deposited film maintains an appropriate hardness, the etching rate of the SiO2 film is appropriate, and the selectivity of the SiO2 film / ACL or SiN film / ACL is good, particularly by adjusting the content of the metal element to 0.5 mass ppb or more.

[0022] The etching gas containing hexafluoro-2-butyne of this disclosure, in particular, has an appropriate concentration of compounds having 2 or 3 carbon atoms and one double or triple bond, by adjusting the content to 95 ppm by volume or less. This suppresses the progression of PR etching mainly due to the activity derived from the double (olefin) or triple bond, and the selectivity of the SiO2 film / PR material is good. Furthermore, the etching gas containing hexafluoro-2-butyne of this disclosure suppresses the formation of a large amount of deposited film, and the etching rate is good.

[0023] The etching gas containing hexafluoro-2-butyne of this disclosure, in particular, has an appropriate concentration of compounds having 2 or 3 carbon atoms and one double or triple bond, by adjusting the content to 0.5 ppm by volume or more, thereby maintaining a good protective effect by the compounds and having good selectivity for SiO2 film / PR material.

[0024] According to this disclosure, it is possible to provide a new etching gas containing hexafluoro-2-butyne.

[0025] In this specification, "contains" is a concept that encompasses all of "contains," "consist essentially of," and "consist of." In this specification, when a numerical range is indicated as "A to B," it means "greater than or equal to A and less than or equal to B." In this specification, when expressions such as parts and percentages are used, they represent parts by mass, parts by weight, mass%, or weight% (wt%).

[0026] [1] Etching Gas This disclosure discloses an etching gas containing hexafluoro-2-butyne (CF3C≡CCF3). The etching gas of this disclosure contains hexafluoro-2-butyne (CF3C≡CCF3) and suppresses polymerization (dimerization, etc.) of alkyne compounds, suppresses pore blockage, and suppresses a decrease in etching performance by adjusting the concentration of specific metal elements or specific alkene and / or alkyne compounds.

[0027] The etching gas of this disclosure contains (1) 1,1,1,4,4,4-hexafluoro-2-butyne (CF3C≡CCF3); and (2) at least one metallic element selected from the group consisting of metallic elements in the third period and metallic elements in the fourth period.

[0028] Preferably, in the etching gas of the present disclosure, the content of (1) 1,1,1,4,4,4-hexafluoro-2-butyne is 99% by volume or more and 99.9995% by volume or less, relative to the total amount of etching gas, and the content of (2) metal elements is 0.5 ppb by mass or more and 40 ppb by mass or less.

[0029] The etching gas of the present disclosure preferably comprises, (2) the metal element, the metal element in the third period being at least one metal element selected from the group consisting of sodium (Na), magnesium (Mg), and aluminum (Al), and the metal element in the fourth period being at least one metal element selected from the group consisting of calcium (Ca) and iron (Fe).

[0030] The etching gas of this disclosure preferably further contains (3) water, wherein the content of (3) water relative to the total amount of etching gas is 0.1 volume ppm or more and 20 volume ppm or less.

[0031] According to this disclosure, an etching gas containing hexafluoro-2-butyne contains at least one metal element selected from the group consisting of metal elements in the third period and metal elements in the fourth period. By using this etching gas to etch silicon oxide films (SiO2 films), silicon nitride films (SiN films), or silicon-based materials containing photoresist (PR, etching mask) materials, good etching can be achieved.

[0032] The etching gas containing hexafluoro-2-butyne of the present disclosure can, in particular, suppress the inclusion of metal in the formed deposition film by adjusting the content of metal elements to 40 mass ppb or less, and the metal concentration is appropriate. The deposition film retains appropriate hardness, maintains an appropriate etching rate of the amorphous carbon layer (ACL), and has a good selectivity of SiO2 film / ACL or SiN film / ACL.

[0033] The etching gas containing hexafluoro-2-butyne of the present disclosure can, in particular, suppress the inclusion of metal in the formed deposition film by adjusting the content of metal elements to 0.5 mass ppb or more, and the metal concentration is appropriate. The deposition film retains appropriate hardness, maintains an appropriate etching rate of the SiO2 film, and has a good selectivity of SiO2 film / ACL or SiN film / ACL.

[0034] The etching gas of the present disclosure contains: (1) 1,1,1,4,4,4-hexafluoro-2-butyne (CF3C≡CCF3); (2) a compound having 2 or 3 carbon atoms and having 1 double bond or triple bond.

[0035] Preferably, in the etching gas of the present disclosure, with respect to the total amount of the etching gas, the content of the (1) 1,1,1,4,4,4-hexafluoro-2-butyne is 99 volume % or more and 99.9995 volume % or less, and the content of the (2) compound having 2 or 3 carbon atoms and having 1 double bond or triple bond is 0.5 volume ppm or more and 95 volume ppm or less.

[0036] Preferably, the (2) compound is at least one halogenated alkene compound (olefin compound) selected from the group consisting of halogenated ethylene compounds represented by the formula CF2=CFX (where X represents a hydrogen atom (H), a chlorine atom (Cl), a bromine atom (Br), or an iodine atom (I)) and hexafluoropropene (CF3-CF=CF2).

[0037] The etching gas of the present disclosure preferably contains the compound (2) represented by the formula CF3C≡CX (where X represents a hydrogen atom (H), a chlorine atom (Cl), a bromine atom (Br), or an iodine atom (I)), which is an alkyne halide compound.

[0038] According to the present disclosure, the etching gas containing hexafluoro-2-butyne contains a compound having 2 or 3 carbon atoms and having 1 double bond or triple bond (an alkene halide compound and an alkyne halide compound). By using this etching gas, when etching is performed on a silicon-based material containing a silicon oxide film (SiO2 film), a silicon nitride film (SiN film), or a photoresist (PR, an etching mask) material, etching can be performed well.

[0039] The etching gas containing hexafluoro-2-butyne of the present disclosure, in particular, adjusts the content of the compound having 2 or 3 carbon atoms and having 1 double bond or triple bond to 95 volume ppm or less. As a result, the concentration of the compound is appropriate, the progress of PR etching mainly due to the activity derived from the compound is suppressed, and the selectivity of the SiO2 film / PR material is good. Further, the etching gas containing hexafluoro-2-butyne of the present disclosure suppresses the generation of a large amount of a deposited film (deposition film), and the etching rate is good.

[0040] The etching gas containing hexafluoro-2-butyne of the present disclosure, in particular, adjusts the content of the compound having 2 or 3 carbon atoms and having 1 double bond or triple bond to 0.5 volume volume volume ppm or more. As a result, the concentration of the compound is appropriate, the protective effect due to the compound is well maintained, and the selectivity of the SiO2 film / PR material is good.

[0041] (1) 1,1,1,4,4,4-Hexafluoro-2-butyne (CF3C≡CCF3) The etching gas of the present disclosure contains (1) 1,1,1,4,4,4-hexafluoro-2-butyne as a first component as a main component.

[0042] In etching gas, from the viewpoint of suppressing polymerization (dimerization, etc.) of halogenated alkyne compounds, suppressing blockage of pores, and suppressing a decrease in etching performance, preferably, with respect to the total amount (gas volume) of etching gas, the content of (1) 1,1,1,4,4,4-hexafluoro-2-butyne is 99% by volume or more and 99.9995% by volume or less, 99% by volume or more and 99.999% by volume or less, more preferably 99.05% to 99.995% by volume, even more preferably 99.1% to 99.99% by volume, and particularly preferably 99.5% to 99.95% by volume.

[0043] (2) At least one component selected from the group consisting of (2-1) metal elements in the third period and metal elements in the fourth period; and (2-2) compounds having 2 or 3 carbon atoms and having one double or triple bond.

[0044] (2-1) At least one metal element selected from the group consisting of metal elements in the third period and metal elements in the fourth period The etching gas of this disclosure contains as a second component (2) At least one metal element selected from the group consisting of metal elements in the third period and metal elements in the fourth period.

[0045] (2) From the viewpoint of suppressing polymerization (dimerization, etc.) of the alkyne halide compound, suppressing blockage of pores, and suppressing a decrease in etching performance, the metal element is preferably at least one metal element selected from the group consisting of sodium (Na), magnesium (Mg), and aluminum (Al) if it is in the third period.

[0046] (2) From the viewpoint of suppressing polymerization (dimerization, etc.) of the alkyne halide compound, suppressing blockage of pores, and suppressing a decrease in etching performance, the metal element is preferably at least one metal element selected from the group consisting of calcium (Ca) and iron (Fe) in the fourth period.

[0047] The etching gas may be (2) a single metal element, or a mixture (blend) of two or more elements.

[0048] In etching gases, from the viewpoint of suppressing polymerization (dimerization, etc.) of halide alkyne compounds, suppressing blockage of pores, and suppressing a decrease in etching performance, preferably, the content of metal elements (total amount of metal elements when the metal elements consist of one type alone or two or more types) relative to the total amount of etching gas is 0.5 mass ppb (wtppb) or more and 40 mass ppb (wtppb) or less, more preferably 0.75 mass ppb to 35 mass ppb, even more preferably 1 mass ppb to 30 mass ppb, and particularly preferably 1.2 mass ppb to 25 mass ppb.

[0049] By using an etching gas containing 1,1,1,4,4,4-hexafluoro-2-butyne and ensuring a metal element content of 0.5 mass ppb or more, the hardening of the deposited film during etching is suppressed, resulting in high etching rates for SiO2 and SiN films, and high selectivity (selectivity ratio) for SiO2 / ACL and SiN / ACL.

[0050] By using an etching gas containing 1,1,1,4,4,4-hexafluoro-2-butyne and limiting the metallic element content to 40 mass ppb or less, the inclusion of metal in the formed deposited film during etching is suppressed, resulting in a deposited film with appropriate hardness. This reduces the etching rate of ACL, and the selectivity for SiO2 film / ACL and SiN film / ACL is high.

[0051] (2-2) Compounds having 2 or 3 carbon atoms and having one double or triple bond (halogenated alkene compounds and halide alkyne compounds) The etching gas of this disclosure contains as a second component (2) a compound having 2 or 3 carbon atoms and having one double or triple bond (halogenated alkene compounds and halide alkyne compounds).

[0052] (2) The compound is preferably at least one halogenated alkene compound (olefin compound) selected from the group consisting of halogenated ethylene compounds represented by the formula CF2=CFX (wherein X represents a hydrogen atom (H), a chlorine atom (Cl), a bromine atom (Br), or an iodine atom (I)) and hexafluoropropene (CF3-CF=CF2), from the viewpoint of suppressing polymerization (dimerization, etc.) of halogenated alkyne compounds (1,1,1,4,4,4-hexafluoro-2-butyne, CF3C≡CCF3), suppressing pore blockage, and suppressing a decrease in etching performance.

[0053] (2) The compound is preferably at least one halogenated alkene compound (olefin compound) selected from the group consisting of chlorotrifluoroethylene (CTFE) and / or hexafluoropropene (HFP), from the viewpoint of suppressing polymerization (dimerization, etc.) of the halogenated alkyne compound (CF3C≡CCF3), suppressing pore blockage, and suppressing a decrease in etching performance, and even more preferably chlorotrifluoroethylene (CTFE).

[0054] (2) The compound is preferably an alkyne halide compound represented by the formula CF3C≡CX (wherein X represents a hydrogen atom (H), a chlorine atom (Cl), a bromine atom (Br), or an iodine atom (I)), from the viewpoint of suppressing polymerization (dimerization, etc.) of the alkyne halide compound (CF3C≡CX), suppressing pore blockage, and suppressing a decrease in etching performance. The alkyne halide compound represented by the formula CF3C≡CX may be used alone or as a mixture (blend) of two or more types.

[0055] (2) The compound is preferably at least one halide alkyne compound selected from the group consisting of CF3C≡CH, CF3C≡CCl, and / or CF3C≡CBr, from the viewpoint of suppressing polymerization (dimerization, etc.) of the halide alkyne compound (CF3C≡CCF3), suppressing pore blockage, and suppressing a decrease in etching performance.

[0056] The etching gas may be (2) compound used alone, or a mixture (blend) of two or more compounds.

[0057] In etching gas, from the viewpoint of suppressing polymerization (dimerization, etc.) of halogenated alkyne compounds (CF3C≡CCF3), suppressing pore blockage, and suppressing a decrease in etching performance, preferably, the content of (2) compound (or the total amount of (2) compound when (2) compound is included as one type or two or more types) is 0.5 volume ppm or more and 95 volume ppm or less, more preferably 0.75 volume ppm to 93 volume ppm, even more preferably 1.0 volume ppm to 90 volume ppm, and particularly preferably 1.5 volume ppm to 85 volume ppm.

[0058] In the etching gas, by including 1,1,1,4,4,4-hexafluoro-2-butyne and ensuring that the compound content is 0.5 ppm or more by volume, a protective effect is observed during etching, resulting in a high selectivity (selectivity ratio) for the SiO2 film / PR.

[0059] In the etching gas, by including 1,1,1,4,4,4-hexafluoro-2-butyne and keeping the content of compound (2) below 95 ppm by volume, etching of PR mainly by the active compound (2) is suppressed during etching, and the selectivity of SiO2 film / PR is good. In the etching gas, by including 1,1,1,4,4,4-hexafluoro-2-butyne and keeping the content of compound (2) below 95 ppm by volume, the formation of a large amount of deposited film (deposition film) during etching is suppressed, and the etching rate is high.

[0060] (3) Water When the etching gas disclosed herein contains as a second component at least one metal element selected from the group consisting of (2-1) metal elements in the third period and metal elements in the fourth period, it is preferable to further contain as a third component (3) water, from the viewpoint of suppressing polymerization (dimerization, etc.) of the halide alkyne compound, suppressing blockage of pores, and suppressing a decrease in etching performance.

[0061] In etching gas, when the second component contains (2-1) at least one metal element selected from the group consisting of metal elements in the third period and metal elements in the fourth period, from the viewpoint of suppressing polymerization (dimerization, etc.) of the halide alkyne compound, suppressing blockage of pores, and suppressing a decrease in etching performance, the water content (3) relative to the total amount (gas volume) of the etching gas is preferably 0.1 volume ppm or more and 20 volume ppm or less, more preferably 0.5 volume ppm to 15 volume ppm, even more preferably 1 volume ppm to 10 volume ppm, and particularly preferably 1.5 volume ppm to 7.5 volume ppm.

[0062] (4) Amount of etching gas used The etching gas of this disclosure contains, as a first component, (1) 1,1,1,4,4,4-hexafluoro-2-butyne (CF3C≡CCF3), as a second component, (2) at least one metal element selected from the group consisting of metal elements in the third period and metal elements in the fourth period, and additionally, (3) water.

[0063] The etching gas of this disclosure contains (1) 1,1,1,4,4,4-hexafluoro-2-butyne (CF3C≡CCF3) as a first component, and (2) a compound having 2 or 3 carbon atoms and one double or triple bond as a second component.

[0064] From the viewpoint of efficiently and effectively carrying out etching, the amount of etching gas used in this disclosure is preferably 2 ccm to 100 ccm, more preferably 5 ccm to 50 ccm, and even more preferably 8 ccm to 15 ccm.

[0065] In this specification, the unit of gas consumption "ccm" represents cubic centimetre / min (cc / min), and is the volume (CC, cm³) when an instantaneous flow rate is maintained for 1 minute under conditions of 25°C and 1 atmosphere. 3 ) represents.

[0066] (5) Other etching gases The etching gas of this disclosure may contain other etching gases as needed, from the viewpoint of promoting good etching.

[0067] The etching rate can be adjusted by using other etching gases, preferably hydrofluorocarbon compounds (HFCs) such as CH2F2, CHF3, C2H2F2, C2H4F2, and C3H2F4; perfluorocarbon compounds (PFCs) such as CF4, C2F6, C3F8, C4F8, C4F6, and C5F8; iodides such as CF3I, C2F5I, and C3F7I; and SF6.

[0068] The etching gas of this disclosure may be used as a single etching gas or as a mixture (blend) of two or more etching gases.

[0069] [2] Method for etching The present disclosure includes a method for etching a semiconductor manufacturing substrate using the etching gas of the present disclosure as a gas supplied to generate plasma.

[0070] The etching method of this disclosure involves etching a silicon-based material on which a silicon oxide film (SiO2 film) or a silicon nitride film (SiN film) is formed using a gas plasma of the etching gas (A) of this disclosure.

[0071] The silicon-based material is preferably a substrate for semiconductor manufacturing.

[0072] The etching method preferably involves continuously supplying (A) an etching gas and (B) an inert gas separately to generate an etching mixture gas in a chamber and etching the silicon-based material.

[0073] The etching method preferably involves continuously supplying (A) an etching gas and (C) an oxidizing gas and / or a reducing gas separately to generate an etching mixed gas in a chamber and etching the silicon-based material.

[0074] The etching method preferably separately and continuously supplies (A) an etching gas, (B) an inert gas, and (C) an oxidizing gas and / or a reducing gas to generate an etching mixed gas in a chamber and etch a silicon-based material.

[0075] By using the etching gas of the present disclosure, when performing hole etching on a silicon-based material containing a silicon oxide film (SiO2 film) or a silicon nitride film (SiN film) with the generated gas plasma, it is possible to perform etching while well maintaining the processed shape of the holes. The conditions of the etching method (especially the dry etching method) can be the same as the conventional methods except for using the etching gas of the present disclosure.

[0076] (1) Examples of etching conditions The conditions for performing etching using the etching gas of the present disclosure are, for example, as follows.

[0077] The flow rate is adjusted to 5 ccm to 2,000 ccm, preferably 10 ccm to 1,000 ccm.

[0078] The discharge power is adjusted to 200 W to 20,000 W, preferably 400 W to 10,000 W. The high-frequency power supply is adjusted to 13.56 MHz, 0.22 W. The bias power is adjusted to 25 W to 15,000 W, preferably 100 W to 10,000 W.

[0079] The pressure is adjusted to 30 mTorr or less (3.99 Pa or less), preferably 2 mTorr to 10 mTorr (0.266 Pa to 1.33 Pa). Unless otherwise specified, the pressure indicates the gauge pressure.

[0080] Electron density 10 9 cm -3 ~10 13 cm -3 、preferably 10 10 cm -3 ~10 12 cm -3 is adjusted. The electron temperature is adjusted to 2 eV to 9 eV, preferably 3 eV to 8 eV.

[0081] The wafer temperature is adjusted to -40°C to 100°C, preferably -30°C to 50°C. The chamber wall temperature is adjusted to -30°C to 300°C, preferably 20°C to 200°C.

[0082] Discharge power and bias power vary depending on the size of the chamber, the size of the electrodes, etc. Inductively coupled plasma (ICP) etching equipment for small-diameter wafers (chamber volume 3,500 cm³) 3 The preferred etching conditions when etching patterns such as contact holes into a silicon oxide film, etc., can be as follows:

[0083] The discharge power is adjusted to 200W to 1,000W, preferably 300W to 600W. The bias power is adjusted to 50W to 500W, preferably 100W to 300W.

[0084] (2) Inert gas When etching is performed using the etching gas of this disclosure, an inert gas may be included in the etching gas as needed, from the viewpoint of promoting good etching.

[0085] The etching method preferably involves supplying an etching gas and an inert gas separately and continuously to generate an etching mixture gas in a chamber, and then etching the silicon-based material.

[0086] The inert gas may preferably contain one or more noble gases, such as nitrogen. The noble gas may preferably contain helium, neon, argon, xenon, krypton, etc., and more preferably argon (Ar).

[0087] When etching is performed using etching gas, the inert gas may be used alone or mixed (blended) with two or more types.

[0088] Inert gases can alter the electron temperature and electron density of a plasma, allowing for control over the balance of fluorocarbon radicals and fluorocarbon ions.

[0089] When etching is performed using an etching gas, if an inert gas (such as Ar) is included, the amount of inert gas used is preferably 50 ccm to 500 ccm, more preferably 150 ccm to 400 ccm, and even more preferably 220 ccm to 280 ccm, from the viewpoint of ensuring good etching.

[0090] When etching is performed using etching gas, if an inert gas (such as Ar) is included, the amount of inert gas used is preferably 5 to 50 times the amount of the etching gas flow rate, more preferably 15 to 40 times, and even more preferably 22 to 28 times, from the viewpoint of ensuring good etching.

[0091] (3) Oxidizing gas and / or reducing gas When etching is performed using the etching gas of this disclosure, the etching gas may contain an oxidizing gas and / or a reducing gas as needed, from the viewpoint of promoting good etching.

[0092] The etching method preferably involves supplying an etching gas and an oxidizing gas and / or a reducing gas separately and continuously to generate an etching mixture gas in a chamber and etching the silicon-based material.

[0093] Preferably, using an oxidizing gas such as O2, O3, NO, N2O, NO2, SO2, COS, CO, or CO2, and more preferably using oxygen (O2), will allow for a good etching shape to be obtained.

[0094] When etching is performed using etching gas, one type of oxidizing gas may be used alone, or two or more types may be mixed (blended) together.

[0095] When etching is performed using an etching gas, if an oxidizing gas (such as O2) is included, the amount of oxidizing gas used is preferably 2 ccm to 100 ccm, more preferably 5 ccm to 50 ccm, and even more preferably 8 ccm to 15 ccm, from the viewpoint of efficiently and effectively carrying out etching.

[0096] When etching is performed using etching gas, if an oxidizing gas (such as O2) is included, the amount of oxidizing gas used is preferably 0.2 to 10 times the amount of the etching gas flow rate, more preferably 0.5 to 5 times, and even more preferably 0.8 to 1.5 times, from the viewpoint of efficiently and effectively carrying out etching.

[0097] By using a reducing gas such as hydrogen (H2), CO, or CH4, it is possible to obtain a good etching shape, especially when performing hole etching on silicon-based materials containing a silicon nitride film (SiN film).

[0098] When etching is performed using etching gas, the reducing gas may be used alone or mixed (blended) with two or more types.

[0099] When etching is performed using an etching gas, if a reducing gas (such as H2) is included, the amount of reducing gas used is preferably 0.5 ccm to 20 ccm, more preferably 0.8 ccm to 10 ccm, and even more preferably 1 ccm to 5 ccm, from the viewpoint of efficiently and effectively carrying out etching.

[0100] When etching is performed using etching gas, if a reducing gas (such as H2) is included, the amount of reducing gas used is preferably 0.05 to 2 times the amount of the etching gas flow rate, more preferably 0.08 to 1 time, and even more preferably 0.1 to 0.5 times, from the viewpoint of efficiently and effectively carrying out etching.

[0101] When etching is performed using etching gas, an oxidizing gas and a reducing gas may be used individually, or two or more may be mixed (blended).

[0102] The etching method preferably involves continuously supplying an etching gas, an inert gas, and an oxidizing gas and / or a reducing gas separately to generate an etching mixture gas in a chamber and etching the silicon-based material.

[0103] [3] Semiconductor manufacturing apparatus The present disclosure includes a semiconductor manufacturing apparatus having a gas ejection section for etching gas of the present disclosure.

[0104] [4] Semiconductor manufacturing method The present disclosure includes a semiconductor manufacturing method in which etching is performed on a semiconductor manufacturing substrate using the etching gas of the present disclosure.

[0105] [5] Use for semiconductor manufacturing The Disclosure includes the use of the etching gas of the Disclosure for semiconductor manufacturing, which involves etching a semiconductor manufacturing substrate.

[0106] The etching gas of this disclosure contains (1) 1,1,1,4,4,4-hexafluoro-2-butyne (CF3C≡CCF3) as a first component, and (2) at least one metal element selected from the group consisting of metal elements in the third period and metal elements in the fourth period as a second component, and additionally contains (3) water. When hole etching is performed using the etching gas of this disclosure, it is possible to suppress hole clogging in the processed shape, reduce side etching, and perform etching while maintaining the processed shape of the hole (deep hole) in good condition.

[0107] The etching gas of this disclosure contains (1) 1,1,1,4,4,4-hexafluoro-2-butyne (CF3C≡CCF3) as a first component, and (2) a compound having 2 or 3 carbon atoms and one double or triple bond as a second component. When hole etching is performed using the etching gas of this disclosure, it is possible to suppress hole clogging in the processed shape, reduce side etching, and perform etching while maintaining the processed shape of the hole (deep hole) in good condition.

[0108] The etching gas of this disclosure can suppress polymerization (dimerization, etc.) of alkyne halogen compounds in the etching gas, suppress blockage of pores, and suppress a decrease in etching performance.

[0109] The present invention will be described in detail below using examples and comparative examples. However, the present invention is not limited to these.

[0110] (Example 1) Second component: At least one metal element selected from the group consisting of metal elements in the third period and metal elements in the fourth period [1] Etching method An etching gas containing (1) 1,1,1,4,4,4-hexafluoro-2-butyne (CF3C≡CCF3) as the first component, (2) at least one metal element selected from the group consisting of metal elements in the third period and metal elements in the fourth period, and (3) water as the second component was introduced from a gas inlet connected to the upper electrode. Then, the process gas was excited by a high-frequency power supply (13.56MHz, 0.22W) and etching was performed.

[0111] Etching gases—oxygen (oxidizing gas), Ar (inert gas), and hydrogen (reducing gas, used when etching SiN films)—were supplied from separate lines to form a mixed etching gas in the chamber, and etching was performed.

[0112] ICP (Inductive Coupled Plasma), discharge power 1,000W, bias power 300W, pressure 10mTorr, electron density 8×10 10 cm -3 ~2 x 10 11 cm -3 Etching was performed on silicon oxide films (SiO2 films) and silicon nitride films (SiN films) formed on silicon substrates under etching conditions of electron temperature [5eV to 7eV].

[0113] [2] Measurement of selectivity of SiO2 film / ACL and SiN film / ACL The selectivity of silicon oxide film (SiO2 film) and silicon nitride film (SiN film) to amorphous carbon layer (ACL) was measured by observing the cross-section of the silicon wafer after etching the SiO2 film and SiN film with respect to the SiO2 film and SiN film. SiO2 film / ACL: Etching rate of SiO2 film relative to ACL SiN film / ACL: Etching rate of SiN film relative to ACL

[0114]

[0115] When etching was performed on silicon-based materials containing SiO2 and SiN films using the etching gas of the example, the etching performance did not decrease, and etching with a high selectivity ratio between SiO2 film / ACL and SiN film / ACL was achieved.

[0116] (Example 2) Second component: A compound having 2 or 3 carbon atoms and one double or triple bond (halogenated alkene compounds and haliden alkyne compounds) [1] Etching method An etching gas containing (1) 1,1,1,4,4,4-hexafluoro-2-butyne (CF3C≡CCF3) as the first component and (2) a compound having 2 or 3 carbon atoms and one double or triple bond as the second component was introduced from a gas inlet connected to the upper electrode. Then, the process gas was excited by a high-frequency power supply (13.56MHz, 0.22W) and etching was performed.

[0117] Etching gases—oxygen (oxidizing gas), Ar (inert gas), and hydrogen (reducing gas, used when etching SiN films)—were supplied from separate lines to form a mixed etching gas in the chamber, and etching was performed.

[0118] ICP (Inductive Coupled Plasma), discharge power 1,000W, bias power 300W, pressure 10mTorr, electron density 8×10 10 cm -3 ~2 x 10 11 cm -3 Etching was performed on a silicon oxide film (SiO2 film) formed on a silicon substrate under etching conditions of electron temperature [5eV to 7eV].

[0119] [2] Measurement of Selectivity of SiO2 Film / PR The selectivity of the silicon oxide film (SiO2 film) to the photoresist (PR, etching mask) material was measured by observing the cross-section of the silicon wafer after etching the SiO2 film and the SiN film using SEM. SiO2 film / PR: Etching rate of the SiO2 film relative to the PR

[0120]

[0121]

[0122] When etching was performed on a silicon-based material containing an SiO2 film using the etching gas of the example, the etching performance did not decrease, and etching with a high selectivity ratio of SiO2 film / PR was possible.

[0123] [3] Industrial applicability The etching gas of this disclosure suppresses polymerization (dimerization, etc.) of alkyne halide compounds, suppresses pore blockage, and suppresses a decrease in etching performance by adjusting the concentration of specific metal elements, or by using specific alkene halide compounds and alkyne halide compounds and adjusting the concentration of said compounds.

[0124] The etching gas of this disclosure contains hexafluoro-2-butyne and also contains at least one component selected from the group consisting of metal elements in the third period and metal elements in the fourth period, and compounds having 2 or 3 carbon atoms and having one double or triple bond. As a result, when etching is performed using this etching gas on silicon oxide films (SiO2 films), silicon nitride films (SiN films), or silicon-based materials containing photoresist (PR, etching mask) materials, good etching can be performed.

[0125] The etching gas containing hexafluoro-2-butyne of this disclosure, in particular, by adjusting the content of metal elements to 40 mass ppb or less, has an appropriate metal concentration, suppresses the inclusion of metal in the formed deposited film, maintains an appropriate hardness in the deposited film, maintains an appropriate etching rate for the amorphous carbon layer (ACL), and exhibits good selectivity for SiO2 film / ACL or SiN film / ACL.

[0126] The etching gas containing hexafluoro-2-butyne of this disclosure has an appropriate metal concentration, the deposited film maintains an appropriate hardness, the etching rate of the SiO2 film is appropriate, and the selectivity of the SiO2 film / ACL or SiN film / ACL is good, particularly by adjusting the content of the metal element to 0.5 mass ppb or more.

[0127] The etching gas containing hexafluoro-2-butyne of this disclosure, in particular, has an appropriate concentration of compounds having 2 or 3 carbon atoms and one double or triple bond, by adjusting the content to 95 ppm by volume or less. This suppresses the progression of PR etching mainly due to the activity derived from these compounds (halogenated alkene compounds and halide alkyne compounds), and the selectivity of the SiO2 film / PR material is good. Furthermore, the etching gas containing hexafluoro-2-butyne of this disclosure suppresses the formation of a large amount of deposited film, and the etching rate is good.

[0128] The etching gas containing hexafluoro-2-butyne of this disclosure, in particular, has an appropriate concentration of compounds having 2 or 3 carbon atoms and one double or triple bond, by adjusting the content to 0.5 volume ppm or more, thereby maintaining a good protective effect by the compounds (halogenated alkene compounds (olefin compounds) and halogenated alkyne compounds), and exhibiting good selectivity for SiO2 film / PR material.

Claims

1. An etching gas comprising: (1) 1,1,1,4,4,4-hexafluoro-2-butyne (CF3C≡CCF3); and (2) at least one component selected from the group consisting of (2-1) metal elements in the third period and metal elements in the fourth period; and (2-2) compounds having 2 or 3 carbon atoms and possessing one double or triple bond.

2. The etching gas according to claim 1, wherein, with respect to the total amount of etching gas, the content of (1) 1,1,1,4,4,4-hexafluoro-2-butyne is 99% by volume or more and 99.9995% by volume or less, and (2) when the composition contains (2-1) the metal element, the content of the metal element is 0.5 ppb by mass or more and 40 ppb by mass or less, or when the composition contains (2-2) the compound, the content of the compound is 0.5 ppm by volume or more and 95 ppm by volume or less.

3. The etching gas according to claim 1, wherein the metal element in the third period is at least one metal element selected from the group consisting of sodium (Na), magnesium (Mg), and aluminum (Al), and the metal element in the fourth period is at least one metal element selected from the group consisting of calcium (Ca) and iron (Fe).

4. The etching gas according to claim 1, wherein the compound is at least one halogenated alkene compound selected from the group consisting of halogenated ethylene compounds represented by the formula CF2=CFX (wherein X represents a hydrogen atom (H), a chlorine atom (Cl), a bromine atom (Br), or an iodine atom (I)) and hexafluoropropene (CF3-CF=CF2).

5. The etching gas according to claim 1, wherein the compound is a halogenated alkyne compound represented by the formula CF3C≡CX (wherein X represents a hydrogen atom (H), a chlorine atom (Cl), a bromine atom (Br), or an iodine atom (I)).

6. The etching gas according to claim 1, wherein when the composition contains (2) (2-1) the metal element, it further contains (3) water, and in the etching gas, the content of (3) water relative to the total amount of etching gas is 0.1 volume ppm or more and 20 volume ppm or less.

7. An etching method comprising etching a silicon-based material on which a silicon oxide film or silicon nitride film is formed using a gas plasma of the etching gas (A) described in any one of claims 1 to 6.

8. The etching method according to claim 7, wherein the silicon-based material is a substrate for semiconductor manufacturing.

9. The etching method according to claim 7, wherein (A) the etching gas and (B) the inert gas are supplied separately and continuously to generate an etching mixed gas in a chamber and etch a silicon-based material.

10. The etching method according to claim 7, comprising supplying (A) the etching gas and (C) the oxidizing gas and / or reducing gas separately and continuously to generate an etching mixed gas in a chamber and etching a silicon-based material.

11. The etching method according to claim 7, comprising supplying (A) an etching gas, (B) an inert gas, and (C) an oxidizing gas and / or a reducing gas separately and continuously to generate an etching mixed gas in a chamber and etching a silicon-based material.

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