Etching method using hexafluoropropene

Abstract

The purpose of the present disclosure is to provide a new etching method using hexafluoropropene. An etching method using hexafluoropropene.

Description

Etching method using hexafluoropropene

[0001] The present disclosure relates to etching methods using hexafluoropropene.

[0002] Patent Document 1 discloses a method for etching silicon-based materials such as silicon oxide films and / or silicon-containing low dielectric constant films using hexafluoropropene.

[0003] International Publication No. WO02 / 021586-A1

[0004] An object of the present disclosure is to provide a new etching method using hexafluoropropene.

[0005] The present disclosure encompasses the following configurations.

[0006] Item 1. An etching gas containing (1) hexafluoropropene, and (2) at least one component selected from the group consisting of hexafluorocyclopropane, pentafluoropropene, and a dimer and / or trimer derived from hexafluoropropene.

[0007] Item 2. The etching gas according to Item 1, containing (1) hexafluoropropene in an amount of 95% by volume to 99.99999% by volume relative to the total amount of the etching gas, and (2) containing at least one component selected from the group consisting of hexafluorocyclopropane, pentafluoropropene, and a dimer and / or trimer derived from hexafluoropropene in an amount of 1 ppm by volume to 1,000 ppm by volume.

[0008] Item 3. An etching method in which a silicon-based material having a silicon oxide film or a silicon nitride film formed thereon is etched with gas plasma of the etching gas according to Item 1.

[0009] Item 4. The etching method according to Item 3, wherein the etching gas and (3) an inert gas are supplied separately and continuously to generate an etching mixed gas in a chamber, and a silicon-based material is etched.

[0010] Item 5. The etching method according to Item 3, wherein the etching gas and (4) an oxidizing gas and / or a reducing gas are supplied separately and continuously to generate an etching mixed gas in a chamber, and a silicon-based material is etched.

[0011] Item 6. The etching method according to Item 3, wherein the etching gas, (3) an inert gas, and (4) an oxidizing gas and / or a reducing gas are separately and continuously supplied to generate an etching mixed gas in a chamber, and a silicon-based material is etched.

[0012] Item 7. The etching method according to any one of Items 3 to 6, wherein the silicon-based material is a substrate for manufacturing a semiconductor.

[0013] The etching gas of the present disclosure contains at least one component selected from the group consisting of (1) hexafluoropropene and (2) hexafluorocyclopropane, pentafluoropropene, and dimers and / or trimers derived from hexafluoropropene. When the etching gas of the present disclosure is used to perform hole etching on silicon-based materials including silicon oxide films (SiO2 films) or silicon nitride films (SiN films), side etching can be reduced and etching can be performed while maintaining the processed shape of the hole (deep hole) in good condition.

[0014] According to the present disclosure, a new etching method using hexafluoropropene can be provided.

[0015] In this specification, "containing" is a concept that encompasses all of "comprise," "consist essentially of," and "consist only of." In this specification, when a numerical range is expressed as "A to B," it means "A or more, B or less." When parts, % and other expressions are used in this specification, these represent parts by mass, parts by weight, mass%, or weight% (wt%).

[0016] [1] Etching gas In semiconductor manufacturing, deep holes have traditionally been etched using hexafluoropropene as an etching gas.

[0017] However, when using only hexafluoropropene as an etching gas during hole etching, side etching occurs and the processed shape of the hole cannot be sufficiently maintained, so further consideration is required.Currently, there are processes that use hexafluoro-1,3-butadiene (C4F6) or other gases to maintain the processed shape of the hole, but hexafluoro-1,3-butadiene is an expensive gas, and the cost of the hole etching process increases.

[0018] The present disclosure encompasses an etching gas containing hexafluoropropene for use in etching semiconductor manufacturing substrates during semiconductor manufacturing.

[0019] The etching gas of the present disclosure contains, as a first component, (1) hexafluoropropene, and, as a second component, (2) at least one component selected from the group consisting of hexafluorocyclopropane, pentafluoropropene, and dimers and / or trimers derived from hexafluoropropene.

[0020] When etching is performed using the etching gas of the present disclosure, an inert gas may be contained.

[0021] When etching is performed using the etching gas of the present disclosure, an oxidizing gas and / or a reducing gas may be contained.

[0022] The etching gas of the present disclosure contains, as a first component, (1) hexafluoropropene, and, as a second component, (2) at least one component selected from the group consisting of hexafluorocyclopropane, pentafluoropropene, and dimers and / or trimers derived from hexafluoropropene. When the etching gas of the present disclosure is used to perform hole etching on a silicon-based material containing a silicon oxide film (SiO2 film) or a silicon nitride film (SiN film), etching can be performed while maintaining the processed shape of the hole (deep hole) well.

[0023] The etching gas of the present disclosure contains the second component, and thus can inexpensively improve side etching by approximately 10% to 30% during hole etching on substrates used in semiconductor manufacturing.

[0024] (1) Hexafluoropropene The etching gas of the present disclosure contains (1) hexafluoropropene (CF3-CF=CF2, also known as hexafluoropropylene, HFP) as a first component.

[0025] The etching gas of the present disclosure contains the first component (1) hexafluoropropene as a main component.

[0026] In the etching gas of the present disclosure, the content of hexafluoropropene is preferably 95% by volume to 99.99999% by volume, more preferably 96% by volume to 99.999% by volume, even more preferably 97% by volume to 99.995% by volume, and particularly preferably 98% by volume to 99.99% by volume, relative to the total amount (gas volume) of the etching gas of the present disclosure, from the viewpoint of reducing side etching and performing etching that favorably maintains the processed shape of the hole when hole etching is performed using the etching gas of the present disclosure.

[0027] (2) At least one component selected from the group consisting of hexafluorocyclopropane, pentafluoropropene, and dimers and / or trimers derived from hexafluoropropene The etching gas of the present disclosure contains, as a second component, (2) at least one component selected from the group consisting of hexafluorocyclopropane, pentafluoropropene, and dimers and / or trimers derived from hexafluoropropene.

[0028] (2-1) Hexafluorocyclopropane The etching gas of the present disclosure contains hexafluorocyclopropane (c-C3F6) as a second component. Therefore, when hole etching is performed using the etching gas of the present disclosure, side etching can be reduced and etching can be performed while maintaining the processed shape of the hole well.

[0029] In the etching gas of the present disclosure, the content of hexafluorocyclopropane is preferably 0.1 ppm by volume (ppm volume) to 1,000 ppm by volume (ppm volume), more preferably 1 ppm by volume to 500 ppm by volume, even more preferably 2.5 ppm by volume to 250 ppm by volume, and particularly preferably 5 ppm by volume to 100 ppm by volume, relative to the total amount (gas volume) of the etching gas of the present disclosure, from the viewpoints of reducing side etching and performing etching while favorably maintaining the processed shape of the hole when hole etching is performed using the etching gas of the present disclosure, suppressing clogging of the hole in the processed shape (hole clogging), and efficiently proceeding with etching.

[0030] (2-2) Pentafluoropropene The etching gas of the present disclosure contains pentafluoropropene (C3HF5) as a second component. Therefore, when hole etching is performed using the etching gas of the present disclosure, side etching can be reduced and etching can be performed while maintaining the processed shape of the hole well.

[0031] The pentafluoropropene of the second component is not particularly limited, and any isomer can be used. As the pentafluoropropene, 1,1,2,3,3-pentafluoropropene (F2C=CF-CHF2), 1,1,3,3,3-pentafluoropropene (F2C=CH-CF3), (E / Z)-1,2,3,3,3-pentafluoro-1-propene (HFC=CF-CF3), etc. are preferably used.

[0032] The etching gas of the present disclosure may be one type of pentafluoropropene (including isomers) used alone, or a mixture (blend) of two or more types.

[0033] In the etching gas of the present disclosure, the content of pentafluoropropene relative to the total amount (gas volume) of the etching gas of the present disclosure is preferably 1 ppm by volume (ppm volume) to 1,000 ppm by volume (ppm volume), more preferably 5 ppm by volume to 500 ppm by volume, even more preferably 10 ppm by volume to 100 ppm by volume, and particularly preferably 20 ppm by volume to 50 ppm by volume, from the viewpoint of reducing side etching when performing hole etching using the etching gas of the present disclosure, performing etching while favorably maintaining the processed shape of the hole, and suppressing clogging of the hole in the processed shape (hole clogging).

[0034] (2-3) Dimer and / or trimer derived from hexafluoropropene The etching gas of the present disclosure contains a dimer and / or trimer derived from hexafluoropropene as a second component. Therefore, when hole etching is performed using the etching gas of the present disclosure, side etching can be reduced and etching can be performed while maintaining the processed shape of the hole well.

[0035] In the etching gas of the present disclosure, the second component, a dimer and / or trimer derived from hexafluoropropene, is a product prepared from hexafluoropropene (C3F6), and is a component different from the first component (1) hexafluoropropene (HFP).

[0036] (a) Method for preparing a dimer derived from hexafluoropropene Dimers derived from hexafluoropropene include the cis isomer and trans isomer shown below, and either isomer can be used in the etching gas of the present disclosure, regardless of the abundance ratio.

[0037] The compounds of formula (I) include both cis and trans isomers unless otherwise specified.

[0038]

[0039] The hexafluoropropene dimer may include (E)-1,1,1,2,3,4,5,5,5-nonafluoro-4-(trifluoromethyl)-2-pentene, (Z)-1,1,1,2,3,4,5,5,5-nonafluoro-4-(trifluoromethyl)-2-pentene, and / or 1,1,1,3,4,4,5,5,5-nonafluoro-2-(trifluoromethyl)-2-pentene.

[0040] The dimer derived from hexafluoropropene can be prepared, for example, by the method described in Japanese Patent Application Laid-Open No. 6-234672.

[0041] In the total amount of hexafluoropropene (HFP)-derived dimers (the total amount of compounds represented by formulas (I), (II), and (III) (HFP dimer mixture), hereinafter referred to as "total HFP dimer amount"), the blending ratio of the compound represented by formula (I) is preferably 1% by mass or more, 10% by mass or more, 30% by mass or more, 40% by mass or more, 45% by mass or more, and particularly preferably 50% by mass or more, based on the total amount of HFP dimer. The blending ratio of the compound represented by formula (I) may be 85% by mass or more based on the total amount of HFP dimer. When the blending ratio of the compound represented by formula (I) in the total amount of HFP dimer is high, the viscosity of the HFP dimer mixture becomes low.

[0042] The blending ratio of the compound represented by formula (I) relative to the total amount of the HFP dimer is preferably 99% by mass or less, 90% by mass or less, 85% by mass or less (or less), 80% by mass or less, and 70% by mass or less, respectively, and particularly preferably 60% by mass or less.

[0043] The blending ratio of the compound represented by formula (I) is adjusted to, for example, 10% by mass or more and 90% by mass or less, 10% by mass or more and 85% by mass or less, 10% by mass or more and less than 85% by mass, 20% by mass or more and less than 85% by mass, 30% by mass or more and 90% by mass or less, 30% by mass or more and less than 85% by mass, 35% by mass or more and less than 85% by mass, 35% by mass or more and less than 60% by mass, 40% by mass or more and less than 85% by mass, 40% by mass or more and less than 80% by mass, 50% by mass or more and less than 85% by mass, 50% by mass or more and 60% by mass or less, 55% by mass or more and 80% by mass or less, 60% by mass or more and 75% by mass or less, or 65% by mass or more and 70% by mass or less, based on the total amount of the HFP dimer.

[0044] The blending ratio of the compound represented by formula (I) relative to the total amount of the HFP dimer is preferably, in order, 30% by mass or more and 90% by mass or less, 40% by mass or more and less than 85% by mass, 40% by mass or more and 80% by mass or less, and 45% by mass or more and 70% by mass or less, and particularly preferably 50% by mass or more and 60% by mass or less.

[0045] (b) Method for preparing trimer derived from hexafluoropropene Trimer derived from hexafluoropropene includes the isomers shown below, and any of the isomers can be used in the etching gas of the present disclosure regardless of the abundance ratio.

[0046] Unless otherwise specified, the compound of formula (I) includes both the E diastereomer (I-(E)) and the Z diastereomer (I-(Z)).

[0047]

[0048] The trimer derived from hexafluoropropene is appropriately selected depending on the desired abundance ratio, and is prepared, for example, by the method described in Chem Bar (1973), Vol. 106, pp. 2950-2959.

[0049] In the total amount of trimers derived from hexafluoropropene (HFP) (the sum of the compounds represented by formulas (I), (II), and (III) (HFP trimer mixture), hereinafter referred to as "total HFP trimer amount"), the content of the compound represented by formula (I) is preferably 1% by mass or more, 10% by mass or more, 30% by mass or more, 40% by mass or more, 45% by mass or more, and particularly preferably 50% by mass or more, based on the total amount of HFP trimer. The content of the compound represented by formula (I) may be 85% by mass or more based on the total amount of HFP trimer. When the content of the compound represented by formula (I) in the total amount of HFP trimer is high, the viscosity of the HFP trimer mixture decreases.

[0050] The blending ratio of the compound represented by formula (I) relative to the total amount of HFP trimer is preferably 99% by mass or less, 90% by mass or less, 85% by mass or less (or less), 80% by mass or less, and 70% by mass or less, respectively, and particularly preferably 60% by mass or less.

[0051] The blending ratio of the compound represented by formula (I) relative to the total amount of HFP trimer is adjusted to, for example, 10% by mass or more and 90% by mass or less, 10% by mass or more and 85% by mass or less, 10% by mass or more and less than 85% by mass, 20% by mass or more and less than 85% by mass, 30% by mass or more and 90% by mass or less, 30% by mass or more and less than 85% by mass, 35% by mass or more and less than 85% by mass, 35% by mass or more and less than 60% by mass, 40% by mass or more and less than 85% by mass, 40% by mass or more and less than 80% by mass, 50% by mass or more and less than 85% by mass, 50% by mass or more and 60% by mass or less, 55% by mass or more and less than 80% by mass, 60% by mass or more and less than 75% by mass, or 65% by mass or more and less than 70% by mass.

[0052] The blending ratio of the compound represented by formula (I) relative to the total amount of the HFP trimer is preferably, in order, 30% by mass or more and 90% by mass or less, 40% by mass or more and less than 85% by mass, 40% by mass or more and 80% by mass or less, and 45% by mass or more and 70% by mass or less, and particularly preferably 50% by mass or more and 60% by mass or less.

[0053] (c) Content of Dimer and / or Trimer The etching gas of the present disclosure may use one type of dimer and / or trimer derived from hexafluoropropene alone, or may use a mixture (blend) of two or more types.

[0054] In the etching gas of the present disclosure, the content of the hexafluoropropene-derived dimer and / or trimer is preferably 0.1 ppm by volume (ppm volume) to 1,000 ppm by volume (ppm volume), more preferably 0.5 ppm by volume to 500 ppm by volume, even more preferably 0.75 ppm by volume to 100 ppm by volume, and particularly preferably 1 ppm by volume to 50 ppm by volume, relative to the total amount (gas volume) of the etching gas of the present disclosure, from the viewpoints of reducing side etching, performing etching that favorably maintains the processed shape of the hole, and suppressing clogging of the hole in the processed shape (hole clogging).

[0055] (2-4) Second Component The etching gas of the present disclosure may use at least one component selected from the group consisting of (second component) hexafluorocyclopropane, pentafluoropropene, and dimers and / or trimers derived from hexafluoropropene, either singly or as a mixture (blend) of two or more.

[0056] The etching gas of the present disclosure, containing the second component, can inexpensively improve side etching (the effect of protecting rough walls) by approximately 10% to 30% during hole etching on substrates used in semiconductor manufacturing. The etching gas of the present disclosure can reduce the amount of chipping of the side walls of holes (side etching).

[0057] (3) Amount of Etching Gas Used The etching gas of the present disclosure contains, as a first component, (1) hexafluoropropene (HFP), and, as a second component, (2) at least one component selected from the group consisting of hexafluorocyclopropane, pentafluoropropene, and dimers and / or trimers derived from hexafluoropropene.

[0058] In order to efficiently carry out etching, the amount of etching gas used in the present disclosure is preferably 2 ccm to 100 ccm, more preferably 5 ccm to 50 ccm, and even more preferably 8 ccm to 15 ccm.

[0059] In this specification, the unit of gas consumption, "ccm," stands for cubic centimetre / min (cc / min), and is the volume (cc, cm) when the instantaneous flow rate continues for 1 minute under conditions of 25°C and 1 atmospheric pressure. 3 )

[0060] (4) Other Etching Gases The etching gas of the present disclosure may contain (5) other etching gases as needed, from the viewpoint of smoothly proceeding with etching.

[0061] The etching rate can be adjusted by using other etching gases such as 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.

[0062] The etching gas of the present disclosure may be used alone or in combination of two or more types of other etching gases (blends).

[0063] [2] Etching Method The present disclosure includes a method for etching a substrate for manufacturing a semiconductor, using the etching gas of the present disclosure as a gas supplied to generate plasma.

[0064] The present disclosure includes a method for 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 of the present disclosure.

[0065] The silicon-based material to be etched is preferably a substrate for semiconductor manufacturing.

[0066] When hole etching is performed on silicon-based materials containing silicon oxide (SiO2) or silicon nitride (SiN) films using the gas plasma generated by using the etching gas disclosed herein, etching can be performed with good retention of the processed hole shape. The conditions for the etching method (particularly the dry etching method) can be the same as those for conventional methods, except for using the etching gas disclosed herein.

[0067] (1) Examples of Etching Conditions Etching conditions can be, for example, as follows:

[0068] The flow rate is adjusted to 5 ccm to 2,000 ccm, preferably 10 ccm to 1,000 ccm.

[0069] 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 and 0.22 W. The bias power is adjusted to 25 W to 15,000 W, preferably 100 W to 10,000 W.

[0070] 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 a gauge pressure.

[0071] electron density 10 9 cm -3 ~10 13 cm -3 , preferably 10 10 cm -3 ~10 12 cm -3 The electron temperature is adjusted to 2 eV to 9 eV, preferably 3 eV to 8 eV.

[0072] The wafer temperature is adjusted to between -40°C and 100°C, preferably between -30°C and 50°C. The chamber wall temperature is adjusted to between -30°C and 300°C, preferably between 20°C and 200°C.

[0073] The discharge power and bias power also vary depending on the size of the chamber and the size of the electrodes. 3 The preferred etching conditions for etching a pattern such as a contact hole in a silicon oxide film or the like using the etching method are as follows:

[0074] The discharge power is adjusted to 200 W to 1,000 W, preferably 300 W to 600 W. The bias power is adjusted to 50 W to 500 W, preferably 100 W to 300 W.

[0075] (2) Inert Gas When etching is performed using the etching gas of the present disclosure, the etching gas of the present disclosure may contain an inert gas as needed, from the viewpoint of smoothly proceeding with etching.

[0076] The etching method of the present disclosure preferably comprises separately and continuously supplying the etching gas of the present disclosure and an inert gas to generate an etching gas mixture in a chamber and etching a silicon-based material.

[0077] The inert gas may preferably contain one or more of rare gases, nitrogen, etc. The rare gas may preferably contain helium, neon, argon, xenon, krypton, etc., and more preferably argon (Ar) is used.

[0078] When etching is performed using the etching gas of the present disclosure, the inert gas may be used alone or in combination (blended) of two or more types.

[0079] The inert gas can change the electron temperature and electron density of the plasma, and can control the balance of fluorocarbon radicals and fluorocarbon ions.

[0080] When etching is performed using the etching gas of the present disclosure, if an inert gas (such as Ar) is contained, the amount of the 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 smoothly proceeding with etching.

[0081] When etching is performed using the etching gas of the present disclosure, if an inert gas (such as Ar) is contained, the amount of the inert gas used is preferably 5 to 50 times, more preferably 15 to 40 times, and even more preferably 22 to 28 times the flow rate of the etching gas, from the viewpoint of smoothly proceeding with etching.

[0082] (3) Oxidizing Gas and / or Reducing Gas When etching is performed using the etching gas of the present disclosure, the etching gas of the present disclosure may contain an oxidizing gas and / or a reducing gas, as necessary, in order to ensure smooth etching.

[0083] In the etching method of the present disclosure, preferably, the etching gas of the present disclosure and an oxidizing gas and / or a reducing gas are separately and continuously supplied to generate an etching mixed gas in a chamber, and the silicon-based material is etched.

[0084] The oxidizing gas is preferably O2, O3, NO, N2O, NO2, SO2, COS, CO, CO2, or the like, and more preferably oxygen (O2), which allows a good etching shape to be obtained.

[0085] When etching is performed using the etching gas of the present disclosure, the oxidizing gas may be used alone or in the form of a mixture (blend) of two or more types.

[0086] When etching is performed using the etching gas of the present disclosure, if an oxidizing gas (such as O2) is contained, the amount of the 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 proceeding with etching.

[0087] When etching is performed using the etching gas of the present disclosure, if an oxidizing gas (such as O2) is contained, the amount of the oxidizing gas used is preferably 0.2 to 10 times, more preferably 0.5 to 5 times, and even more preferably 0.8 to 1.5 times the flow rate of the etching gas, from the viewpoint of efficiently proceeding with etching.

[0088] The reducing gas is preferably hydrogen (H2), CO, CH4, or the like, which allows for a good etching shape to be obtained, particularly when performing hole etching on silicon-based materials containing silicon nitride films (SiN films).

[0089] When etching is performed using the etching gas of the present disclosure, the reducing gas may be used alone or in the form of a mixture (blend) of two or more types.

[0090] When etching is performed using the etching gas of the present disclosure, if a reducing gas (such as H) is contained, the amount of the 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 proceeding with etching.

[0091] When etching is performed using the etching gas of the present disclosure, if a reducing gas (such as H) is contained, the amount of the reducing gas used is preferably 0.05 to 2 times, more preferably 0.08 to 1 time, and even more preferably 0.1 to 0.5 times the flow rate of the etching gas, from the viewpoint of efficiently proceeding with etching.

[0092] When etching is performed using the etching gas of the present disclosure, the oxidizing gas and reducing gas may be used alone, or two or more types may be mixed (blended) and used.

[0093] The etching method of the present disclosure preferably comprises separately and continuously supplying the etching gas of the present disclosure, an inert gas, and an oxidizing gas and / or a reducing gas in a chamber to generate an etching mixed gas and etch the silicon-based material.

[0094] [3] Semiconductor manufacturing apparatus The present disclosure encompasses a semiconductor manufacturing apparatus having a gas ejection portion for the etching gas of the present disclosure.

[0095] [4] Semiconductor Manufacturing Method The present disclosure encompasses a semiconductor manufacturing method in which etching is performed on a semiconductor manufacturing substrate using the etching gas of the present disclosure.

[0096] [5] Use for semiconductor manufacturing The present disclosure includes the use of the etching gas of the present disclosure for etching a substrate for semiconductor manufacturing, in semiconductor manufacturing.

[0097] The etching gas of the present disclosure contains, as a first component, (1) hexafluoropropene, and, as a second component, (2) at least one component selected from the group consisting of hexafluorocyclopropane, pentafluoropropene, and dimers and / or trimers derived from hexafluoropropene. When hole etching is performed using the etching gas of the present disclosure, clogging of the hole in the processed shape (hole clogging) can be suppressed, side etching can be reduced, and etching can be performed while well maintaining the processed shape of the hole (deep hole).

[0098] The etching gas of the present disclosure, containing the second component, can inexpensively improve side etching (the effect of protecting rough walls) by approximately 10% to 30% during hole etching on substrates used in semiconductor manufacturing. The etching gas of the present disclosure can reduce the amount of chipping of the side walls of holes (side etching).

[0099] The present invention will be specifically described below using examples and comparative examples, but the present invention is not limited to these examples alone.

[0100] [1] Etching method After introducing hexafluoropropene (HFP) and an additive gas (second component) through a gas inlet connected to the upper electrode, etching was performed by exciting the process gas using a high-frequency power supply (13.56 MHz, 0.22 W).

[0101] Etching gas containing HFP and additive gas, oxygen (oxidizing gas), Ar (inert gas), and hydrogen (reducing gas, when etching SiN film) were supplied from separate lines to form a mixed etching gas in the chamber, and etching was performed.

[0102] ICP (Inductive Coupled Plasma), discharge power 1,000W, bias power 300W, pressure 10mTorr, electron density 8×10 10 cm -3 ~2×10 11 cm -3Etching was performed on a silicon oxide film (SiO2 film) and a silicon nitride film (SiN film) formed on a silicon substrate under etching conditions of [electron temperature 5 eV to 7 eV].

[0103] [2] Measurement of aspect ratio and side etching The aspect ratio and side etching (amount of sidewall removal) were measured by observing the cross section of the silicon wafer after etching using an SEM.

[0104] (1) Aspect ratio When etching holes in SiO2 and SiN films, this represents the hole depth (relative value α) (etching depth / etching width (dimension)) relative to the hole width (1). The deeper the etching (high aspect ratio etching), the larger the aspect ratio (high aspect ratio).

[0105] (2) Side Etching Rate In the examples, the side etching rate (relative value) is low enough to reduce side etching compared to the comparative example (example not containing additive gas). Side Etching Rate R = a / b*100

[0106]

[0107]

[0108]

[0109]

[0110]

[0111] When hole etching was performed on silicon-based materials containing SiO2 film and SiN film using the etching gas of the example, side etching was reduced (the side etching rate was lower than in the comparative example), and etching was performed while maintaining the processed shape of the hole well.

[0112] The etching gas of the example was able to improve side etching by about 10% to 30% during hole etching, and was able to effectively reduce side etching.

[0113] [3] Industrial Applicability The etching gas of the present disclosure contains, as a first component, (1) hexafluoropropene, and, as a second component, (2) at least one component selected from the group consisting of hexafluorocyclopropane, pentafluoropropene, and dimers and / or trimers derived from hexafluoropropene. When the etching gas of the present disclosure is used to perform hole etching on a silicon-based material containing a silicon oxide film (SiO film) or a silicon nitride film (SiN film), side etching can be reduced and etching can be performed while favorably maintaining the processed shape of the hole (deep hole).

[0114] The etching gas of the present disclosure, containing the second component, can inexpensively improve side etching (the effect of protecting rough walls) by approximately 10% to 30% during hole etching on substrates used in semiconductor manufacturing. The etching gas of the present disclosure can reduce the amount of chipping of the side walls of holes (side etching).

Claims

1. An etching gas containing (1) hexafluoropropene, and (2) at least one component selected from the group consisting of hexafluorocyclopropane, pentafluoropropene, and dimers and / or trimers derived from hexafluoropropene.

2. The etching gas according to claim 1, comprising, relative to the total amount of the etching gas, (1) hexafluoropropene in an amount of 95% by volume to 99.99999% by volume, and (2) at least one component selected from the group consisting of hexafluorocyclopropane, pentafluoropropene, and a dimer and / or trimer derived from hexafluoropropene in an amount of 1 ppm by volume to 1,000 ppm by volume.

3. An etching method in which a silicon-based material having a silicon oxide film or a silicon nitride film formed thereon is etched using gas plasma of the etching gas according to claim 1.

4. The etching method according to claim 3, wherein the etching gas and (3) the inert gas are supplied separately and continuously to generate an etching mixed gas in a chamber, and a silicon-based material is etched.

5. The etching method according to claim 3, wherein the etching gas and (4) an oxidizing gas and / or a reducing gas are supplied separately and continuously to generate an etching mixed gas in a chamber, and a silicon-based material is etched using the etching mixed gas.

6. The etching method according to claim 3, wherein the etching gas, (3) an inert gas, and (4) an oxidizing gas and / or a reducing gas are supplied separately and continuously to generate an etching mixed gas in a chamber, and a silicon-based material is etched.

7. The etching method according to any one of claims 3 to 6, wherein the silicon-based material is a substrate for manufacturing a semiconductor.

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