Metal removal method, dry etching method, and method for manufacturing semiconductor element

Abstract

Provided is a metal removal method that can be implemented at low cost. This metal removal method is provided with: a reaction step in which a treatment gas containing a fluorine-containing interhalogen compound is brought into contact with a metal-containing material containing a metal element, and a metal fluoride, which is a reaction product of the fluorine-containing interhalogen compound and the metal element, is generated; in the volatilization process, the metal fluoride is heated in an inert gas atmosphere or a vacuum environment so as to be volatilized. The metal element is selected from at least one of iron, cobalt, nickel, selenium, molybdenum, rhodium, palladium, tungsten, rhenium, iridium and platinum.

Description

[0001] This application is a divisional application of a Chinese patent application filed on April 17, 2020, with application number 202080031010.5 and invention name “Metal removal method, dry etching method and method for manufacturing semiconductor element”. Technical Field

[0002] The present invention relates to a metal removal method, a dry etching method and a method for manufacturing a semiconductor element. Background Art

[0003] As magnetic materials or wiring materials constituting semiconductor elements such as nonvolatile memory elements, transition metal elements such as iron (Fe), cobalt (Co), nickel (Ni), selenium (Se), molybdenum (Mo), rhodium (Rh), palladium (Pd), tungsten (W), rhenium (Re), iridium (Ir), and platinum (Pt) are sometimes used. In the manufacturing process of semiconductor elements, sputtering or wet etching is sometimes used when etching a metal thin film on a substrate to form wiring.

[0004] Prior art literature

[0005] Patent Document 1: Japanese Patent Publication No. 228487, 2004 Summary of the invention

[0006] However, in the sputtering method or the wet etching method, even the portion of the semiconductor element that should not be etched is etched, and there is a possibility that the characteristics of the semiconductor element will be lost.

[0007] In addition, Patent Document 1 discloses a method of dry etching a metal thin film on a substrate using an etching gas excited by plasma, but there is a problem that the etching method using plasma is costly.

[0008] An object of the present invention is to provide a metal removal method, a dry etching method, and a method for manufacturing a semiconductor element that can be implemented at low cost.

[0009] In order to solve the above-mentioned problems, one embodiment of the present invention is as shown in the following [1] to [9].

[0010] [1] A metal removal method comprising a reaction step and a volatilization step,

[0011] The reaction step brings the treatment gas containing the fluorine-containing interhalogen compound into contact with the metal-containing material containing the metal element, thereby generating a metal fluoride which is a reaction product of the fluorine-containing interhalogen compound and the metal element.

[0012] The volatilization step heats the metal fluoride in an inert gas atmosphere or a vacuum environment to volatilize it.

[0013] The metal element is at least one selected from iron, cobalt, nickel, selenium, molybdenum, rhodium, palladium, tungsten, rhenium, iridium and platinum.

[0014] [2] The metal removal method according to [1], wherein the fluorine-containing interhalogen compound is at least one selected from chlorine monofluoride, bromine monofluoride, chlorine trifluoride, chlorine pentafluoride, bromine pentafluoride and iodine heptafluoride.

[0015] [3] The metal removal method according to [1] or [2], wherein the processing gas contains at least one inert gas selected from nitrogen, helium, neon, argon, krypton and xenon.

[0016] [4] The metal removal method according to any one of [1] to [3], wherein the reaction temperature of the fluorine-containing interhalogen compound and the metal element in the reaction step is 0° C. or higher and 100° C. or lower.

[0017] [5] The metal removal method according to any one of [1] to [4], wherein the heating temperature of the metal fluoride in the volatilization step is higher than the reaction temperature of the fluorine-containing interhalogen compound and the metal element in the reaction step.

[0018] [6] The metal removal method according to [5], wherein the heating temperature of the metal fluoride in the volatilization step is 50° C. or higher and 400° C. or lower.

[0019] [7] According to the metal removal method described in any one of [1] to [6], in the reaction step, the processing gas is brought into contact with a silicon-containing material and the metal-containing material, and the silicon-containing material contains at least one of silicon oxide and silicon nitride.

[0020] [8] A dry etching method using the metal removal method described in any one of [1] to [7].

[0021] [9] A method for manufacturing a semiconductor element, comprising a dry etching step, wherein the dry etching step uses the dry etching method described in [8] to remove at least a portion of the metal-containing layer from a semiconductor substrate having a metal-containing layer, wherein the metal-containing layer contains at least one metal element selected from iron, cobalt, nickel, selenium, molybdenum, rhodium, palladium, tungsten, rhenium, iridium and platinum.

[0022] According to the present invention, metal removal and dry etching can be performed at low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram showing the structure of a reaction apparatus used in Examples, Comparative Examples, and Reference Examples.

[0024] Figure 2 This is a diagram for explaining samples used in Examples and the like. DETAILED DESCRIPTION

[0025] Hereinafter, an embodiment of the present invention will be described. Furthermore, this embodiment is a method for representing an example of the present invention, and the present invention is not limited to this embodiment. In addition, various changes or improvements can be applied to this embodiment, and such a method after applying changes or improvements is also included in the present invention.

[0026] In order to solve the above-mentioned problems, the present inventors conducted various studies and found that by contacting a fluorine-containing halogen compound with a metal element such as W and / or Ir to generate a reaction product of the metal element and the fluorine-containing halogen compound, namely a metal fluoride, and then heating the metal fluoride under a reduced pressure environment to volatilize the metal fluoride, the metal-containing material containing the metal element can be removed, thereby completing the present invention.

[0027] That is, the metal removal method of one embodiment of the present invention comprises a reaction process and a volatilization process. The reaction process brings the treatment gas containing the fluorine-containing halogen compound into contact with the metal-containing material containing the metal element to generate the reaction product of the fluorine-containing halogen compound and the metal element, namely, the metal fluoride. The volatilization process heats the metal fluoride in an inert gas atmosphere or a vacuum environment to volatilize it. In addition, the metal element contained in the metal-containing material is at least one selected from iron, cobalt, nickel, selenium, molybdenum, rhodium, palladium, tungsten, rhenium, iridium and platinum. In the metal removal method of this embodiment, the metal can be removed by alternating and repeating the reaction process and the volatilization process. Alternatively, the reaction process and the volatilization process can be performed simultaneously.

[0028] In the reaction process, the fluorine-containing interhalogen compound (such as BrF 5 ) reacts with the metal element contained in the metal-containing material to generate what is presumed to be a fluorine-containing or halogen-containing metal complex (e.g. [BrF 4 ]MF 6 ] wherein M is a metal element. ) is a metal fluoride, thereby significantly increasing the mass of the metal-containing material. Since such metal fluorides have a higher vapor pressure than simple substances, oxides, nitrides, etc. of metal elements, they are volatilized and removed by heating in the volatilization step.

[0029] According to the metal removal method of this embodiment, since it is not necessary to put the fluorine-containing halogen compound into an excited state such as plasma, the metal removal can be implemented at a low cost, and the reaction container, piping, etc. used in the metal removal method of this embodiment and the dry etching method of this embodiment described later are not easily corroded.

[0030] Furthermore, according to the metal removal method of the present embodiment, even stable metals such as iron, cobalt, nickel, selenium, molybdenum, rhodium, palladium, tungsten, rhenium, iridium, and platinum can be easily removed.

[0031] Furthermore, if the metal removal method of this embodiment is used, metal deposits can be removed from components and devices and cleaned. For example, metal deposits containing the above-mentioned metal elements such as Ir and W are attached to the inner surface of a chamber (for example, a chamber constituting a semiconductor manufacturing device) in which a reaction involving the above-mentioned metal elements is carried out. In this case, if the metal removal method of this embodiment is implemented in the chamber, the metal deposits attached to the inner surface of the chamber can be removed (cleaned) at low cost. For example, as long as it is a chamber constituting a semiconductor manufacturing device, the above-mentioned cleaning can be performed as a subsequent process of forming a metal-containing material containing the above-mentioned metal elements on a semiconductor substrate to form a metal-containing layer, or as a subsequent process of etching the metal-containing layer.

[0032] Furthermore, dry etching can be performed using the metal removal method of this embodiment. That is, the dry etching method of another embodiment of the present invention is a dry etching method for performing metal etching using the above-mentioned metal removal method. The dry etching method of this embodiment does not require the use of plasma, so etching can be performed at a low cost.

[0033] Furthermore, the dry etching method of this embodiment can be used to manufacture a semiconductor element. That is, the method for manufacturing a semiconductor element according to another embodiment of the present invention includes a dry etching step, which uses the above-mentioned dry etching method to remove at least a portion of the metal-containing layer from a semiconductor substrate having a metal-containing layer, wherein the metal-containing layer contains at least one metal element selected from iron, cobalt, nickel, selenium, molybdenum, rhodium, palladium, tungsten, rhenium, iridium and platinum.

[0034] If the above-mentioned metal-containing layer is formed on a semiconductor substrate and a mask having a predetermined pattern is formed on the metal-containing layer, and then etching is performed using the above-mentioned dry etching method, a portion of the metal-containing layer can be removed from the semiconductor substrate and the above-mentioned pattern can be transferred to the metal-containing layer, thereby forming wiring, etc. on the semiconductor substrate.

[0035] According to the manufacturing method of the semiconductor element of this embodiment, it is not necessary to use plasma, so the semiconductor element can be manufactured at a low cost. In addition, when the wet etching method is used, there is a problem that even the part of the semiconductor element that should not be etched is etched, and the characteristics of the semiconductor element may be lost. However, in the manufacturing method of the semiconductor element of this embodiment, the metal-containing layer is removed by the dry etching method, so the above problem is not easy to occur.

[0036] Hereinafter, the metal removal method according to the present embodiment will be described in more detail.

[0037] The metal-containing material containing metal elements can be a single metal of the above-mentioned metal elements, a compound of the above-mentioned metal elements (such as metal oxides, metal nitrides, metal halides, metal salts), or an alloy of two or more of the above-mentioned metal elements.

[0038] In addition, the metal-containing material containing the metal element may be composed only of the above-mentioned simple metal, compound, alloy, or other components. That is, it may be a mixture consisting of at least one of the above-mentioned simple metal, compound, alloy and other components. As an example of the mixture, a composition consisting of an alloy of each of the above-mentioned metal elements and another metal element, at least one of the above-mentioned simple metal, compound, alloy and other components can be cited. In the mixture, the composition ratio of the above-mentioned simple metal, compound, alloy is preferably 30% by mass or more, more preferably 50% by mass or more.

[0039] The shape of the metal-containing material containing the metal element is not particularly limited, and may be in the form of a film, foil, powder, or block.

[0040] The type of the fluorine-containing interhalogen compound is not particularly limited, and can be selected from chlorine monofluoride (ClF), bromine monofluoride (BrF), chlorine trifluoride (ClF 3 ), iodine trifluoride (IF 3 ), chlorine pentafluoride (ClF 5 ), bromine pentafluoride (BrF 5 ) and iodine heptafluoride (IF 7 Among the above-mentioned fluorine-containing interhalogen compounds, bromine pentafluoride and iodine heptafluoride are more preferred.

[0041] The reaction temperature of the fluorine-containing interhalogen compound and the metal element in the reaction step must be a temperature at which the fluorine-containing interhalogen compound contained in the processing gas can exist in a gaseous state (a temperature above the boiling point of the fluorine-containing interhalogen compound). In addition, the reaction temperature of the fluorine-containing interhalogen compound and the metal element in the reaction step is preferably 0°C or more and 100°C or less, more preferably 10°C or more and 80°C or less, and further preferably 15°C or more and 50°C or less.

[0042] When the reaction temperature is within the above range, the reaction rate of the fluorine-containing interhalogen compound and the above metal element is likely to be sufficiently high, and the fluorine-containing interhalogen compound and substances other than the above metal element (for example, substances that should not react) are unlikely to react.

[0043] If fluorine gas is used, highly volatile metal fluorides can be generated and removed by the reaction of fluorine gas with metal elements, but in the case of not using plasma, a high temperature of 150° C. or higher is required to make fluorine gas react with the above-mentioned metal elements. Under such high temperature conditions, since fluorine gas may react with silicon, silicon oxide, etc. (equivalent to the above-mentioned "substances that should not react"), it is difficult to apply the metal removal method and dry etching method of this embodiment to the manufacturing process of semiconductor elements.

[0044] The processing gas used in the reaction step may be formed only by the fluorine-containing interhalogen compound, or may be a mixed gas containing other types of gases. When the processing gas is a mixed gas, in order to obtain a sufficient reaction rate, the concentration of the fluorine-containing interhalogen compound in the processing gas is preferably 1 volume % or more, more preferably 5 volume % or more, and further preferably 10 volume % or more.

[0045] As other types of gases used when the processing gas is a mixed gas, nitrogen (N 2 ), at least one inert gas selected from the group consisting of helium (He), neon (Ne), argon (Ar), krypton (Kr), and xenon (Xe). The concentration of the inert gas in the processing gas may be, for example, in the range of 0 volume % to 90 volume %.

[0046] The atmospheric pressure in the reaction step is not particularly limited, and may be, for example, 0.1 kPa to 101.3 kPa. The flow rate of the process gas may be appropriately determined to maintain the atmospheric pressure within a certain range according to the size of the reaction vessel and the capacity of the vacuum exhaust device for reducing the pressure in the reaction vessel.

[0047] The volatilization step is performed by heating the metal fluoride in an inert gas atmosphere or a vacuum environment.

[0048] In order to volatilize the metal fluoride quickly, the heating temperature of the metal fluoride in the volatilization step is preferably a temperature higher than the reaction temperature of the fluorine-containing interhalogen compound and the metal element in the reaction step. For example, the heating temperature of the metal fluoride in the volatilization step is preferably 5°C or more higher than the reaction temperature of the fluorine-containing interhalogen compound and the metal element in the reaction step, more preferably 10°C or more higher, and further preferably 20°C or more higher.

[0049] The heating temperature of the metal fluoride in the volatilization step is not particularly limited as long as the metal fluoride can be volatilized, but is preferably 40°C to 500°C, more preferably 45°C to 400°C, further preferably 50°C to 400°C, and even more preferably 50°C to 350°C.

[0050] When the heating temperature of the metal fluoride in the volatilization step is within the above range, the volatilization rate of the metal fluoride is likely to be sufficiently high, and the time and energy required for the volatilization of the metal fluoride are unlikely to be excessively long.

[0051] As the inert gas, for example, at least one selected from nitrogen, helium, neon, argon, krypton and xenon can be used. The inert gas atmosphere is preferably an atmosphere in which the inert gas is circulated at a pressure of 0.1 kPa to 101.3 kPa. In addition, the vacuum environment in the volatilization step is preferably an environment reduced in pressure to 0.1 Pa to 100 Pa.

[0052] Furthermore, with BrF 5 The fluorine-containing interhalogen compound represented by fluorine does not react with silicon oxide and silicon nitride substantially at a temperature below 100° C. and / or in a non-excited state. Therefore, when the processing gas is brought into contact with both the silicon-containing material containing at least one of silicon oxide and silicon nitride and the metal-containing material containing the above-mentioned metal element in the reaction step, the silicon-containing material containing at least one of silicon oxide and silicon nitride is substantially not removed, and the metal-containing material containing the above-mentioned metal element is selectively removed.

[0053] Therefore, if dry etching using the metal removal method of this embodiment is performed on a semiconductor substrate having a metal-containing layer containing the above-mentioned metal element and a silicon-containing layer containing at least one of silicon oxide and silicon nitride, the silicon-containing layer is basically not etched, and at least a portion of the metal-containing layer can be etched to manufacture a semiconductor element.

[0054] Example

[0055] The present invention will be described in more detail below with reference to Examples, Comparative Examples and Reference Examples. Figure 1 The structure of the reaction apparatus 1 used in Examples, Comparative Examples, and Reference Examples will be described.

[0056] Figure 1 The reaction device 1 includes a chamber 3 for carrying out the reaction, and a stage 5 for placing a sample 7 is provided in the chamber 3. In addition, the chamber 3 includes a gas inlet 11, a gas outlet 13, a decompression device (not shown) and a pressure gauge 15. The gas inlet 11 introduces a processing gas (hereinafter, the gas that reacts with the metal in the processing gas is sometimes referred to as "etching gas") into the chamber 3, the gas outlet 13 discharges the processing gas and metal fluoride from the chamber 3, the decompression device decompresses the chamber 3, and the pressure gauge 15 measures the pressure in the chamber 3.

[0057] The stage 5 also functions as a heating device, and can heat the sample 7 on the stage 5 to a desired temperature. The reaction device 1 also includes a heating device (not shown) for heating the outer wall of the chamber 3, and can control the temperature inside the chamber 3 to a desired level.

[0058] If the sample 7 is placed on the stage 5, heated by the stage 5 and at least one of the above-mentioned heating devices, and the processing gas is introduced into the chamber 3 from the gas inlet port 11, the processing gas contacts the sample 7 under a predetermined temperature condition, and the metal of the sample 7 reacts with the processing gas. Thereafter, in order to volatilize the metal fluoride generated in the above-mentioned reaction, the temperature in the chamber 3 is reset to a predetermined temperature, and the gas containing the metal fluoride is discharged from the gas outlet 13 to the outside of the chamber 3 and removed. In the process of removing the metal fluoride, the processing gas may be always introduced into the chamber 3 from the gas inlet port 11, and the gas outlet 13 may be opened to discharge the processing gas and / or the gas containing the metal fluoride to the outside of the chamber 3.

[0059] The reaction device 1 can be used to perform dry etching of metal using the processing gas as an etching gas. By using the dry etching of metal using the reaction device 1, wiring can be formed by etching a metal film (metal-containing layer) on a semiconductor substrate having a silicon-containing material, so the reaction device 1 can be used to manufacture semiconductor elements.

[0060] Next, the metal removal treatments of Examples, Comparative Examples, and Reference Examples performed using the reaction apparatus 1 will be described.

[0061] [Example 1-1]

[0062] Ir powder (produced by Furuya Metals Co., Ltd., average particle size 0.3 μm, purity 99.9%) as sample 7 was placed on stage 5, and sample 7 was heated to 30°C by stage 5. BrF 5 The gas is introduced from the gas inlet 11 to a volume of 2500cm 3 The processing gas is passed through the chamber 3 and discharged from the gas outlet 13 to the outside of the chamber 3, thereby circulating the processing gas in the chamber 3 (reaction process). The processing gas is circulated at a flow rate of 100 sccm for 10 minutes. The pressure in the chamber 3 is 101 kPa. Here, sccm is the volume flow rate (cm2) per minute standardized under the conditions of 0°C and 1 atmosphere. 3 ).

[0063] After the flow of the processing gas is completed, the pressure in the chamber 3 is reduced to below 100 Pa, and the sample 7 is heated to 100° C. using the stage 5 (volatilization process). After the sample 7 is heated for 30 minutes, the chamber 3 is replaced with nitrogen, the sample 7 is taken out, and the mass of the sample 7 is measured. Then, the mass reduction rate of the sample 7 is calculated according to the following formula. The results are shown in Table 1.

[0064] Mass reduction rate (%) = ([mass of sample 7 before metal removal treatment] - [mass of sample 7 after metal removal treatment]) / [mass of sample 7 before metal removal treatment]

[0065] The average particle size of the powder such as the Ir powder is determined on a volume basis using a laser diffraction / scattering particle size distribution measuring apparatus Partica LA-960 manufactured by Horiba, Ltd.

[0066] Table 1

[0067]

[0068] [Example 1-2]

[0069] Set the etching gas to IF 7 The metal removal treatment was carried out in the same manner as in Example 1-1 except for the above, and the mass reduction rate was calculated. The results are shown in Table 1.

[0070] [Examples 1-3]

[0071] The reaction temperature of the reaction step was set to 0°C, and the pressure of the chamber 3 was set to 10 -2 The metal removal treatment was carried out in the same manner as in Example 1-1 except that the mass reduction rate was 0.1 MPa. The results are shown in Table 1.

[0072] [Examples 1-4]

[0073] The metal removal treatment was carried out in the same manner as in Example 1-2 except that the reaction temperature in the reaction step was 0° C., and the mass reduction rate was calculated. The results are shown in Table 1.

[0074] [Examples 1-5]

[0075] Set the etching gas and flow rate to BrF 5 The metal removal treatment was carried out in the same manner as in Example 1-1 except that / Ar=50 sccm / 50 sccm, and the mass reduction rate was calculated.

[0076] [Examples 1-6]

[0077] Set the etching gas and flow rate to BrF 5The metal removal treatment was carried out in the same manner as in Example 1-1 except that / He=50 sccm / 50 sccm, and the mass reduction rate was calculated.

[0078] [Examples 1-7]

[0079] Set the etching gas and flow rate to BrF 5 / N 2 The metal removal process was carried out in the same manner as in Example 1-1 except that the mass reduction rate was calculated. The results are shown in Table 1.

[0080] [Examples 1-8]

[0081] Set the etching gas and flow rate to BrF 5 / N 2 The metal removal process was carried out in the same manner as in Example 1-1 except that the mass reduction rate was calculated. The results are shown in Table 1.

[0082] [Examples 1-9]

[0083] Set the etching gas and flow rate to IF 7 The metal removal treatment was carried out in the same manner as in Example 1-1 except that / Ar=50 sccm / 50 sccm, and the mass reduction rate was calculated.

[0084] [Examples 1-10]

[0085] Set the etching gas and flow rate to IF 7 The metal removal treatment was carried out in the same manner as in Example 1-1 except that / He=50 sccm / 50 sccm, and the mass reduction rate was calculated.

[0086] [Examples 1-11]

[0087] Set the etching gas and flow rate to IF 7 / N 2 The metal removal process was carried out in the same manner as in Example 1-1 except that the mass reduction rate was calculated. The results are shown in Table 1.

[0088] [Examples 1-12]

[0089] Set the etching gas and flow rate to IF 7 / N 2 The metal removal process was carried out in the same manner as in Example 1-1 except that the mass reduction rate was calculated. The results are shown in Table 1.

[0090] [Comparative Example 1-1]

[0091] Set the etching gas to F 2 The metal removal treatment was carried out in the same manner as in Example 1-1 except for the above, and the mass reduction rate was calculated. The results are shown in Table 1.

[0092] [Comparative Example 1-2]

[0093] The volatilization step was not performed, and the chamber 3 was replaced with nitrogen after the reaction step to take out the sample 7 and measure the mass of the sample 7. The metal removal treatment was performed in the same manner as in Example 1-1, and the mass reduction rate was calculated. The results are shown in Table 1.

[0094] [Example 2-1], [Example 2-2] and [Comparative Example 2-1]

[0095] As sample 7, W powder (manufactured by Nilaco Corporation, average particle size 3 μm, purity 99.9%) was used and treated under the conditions shown in Table 1. Table 1 shows the results.

[0096] [Example 3-1], [Example 3-2] and [Comparative Example 3-1]

[0097] As sample 7, Se powder (manufactured by NACALAI TESQUE CO., LTD., average particle size 10 μm, purity 99.9%) was used and treated under the conditions shown in Table 1. Table 1 shows the results.

[0098] [Example 4-1], [Example 4-2] and [Comparative Example 4-1]

[0099] As sample 7, Mo powder (manufactured by Allied Material Co., Ltd. (ALMT), average particle size 6 μm, purity 99.9%) was used and treated under the conditions shown in Table 1. Table 1 shows the results.

[0100] [Example 5-1], [Example 5-2] and [Comparative Example 5-1]

[0101] As sample 7, Rh powder (manufactured by Kojundo Chemical Co., Ltd., average particle size 30 μm, purity 99.9%) was used and treated under the conditions shown in Table 1. Table 1 shows the results.

[0102] [Example 6-1], [Example 6-2] and [Comparative Example 6-1]

[0103] As sample 7, Pd powder (manufactured by Aida Chemical Industry Co., Ltd., average particle size 8 μm, purity 99.9%) was used and treated under the conditions shown in Table 1. Table 1 shows the results.

[0104] [Example 7-1], [Example 7-2] and [Comparative Example 7-1]

[0105] As sample 7, Re powder (manufactured by New Metals and Chemicals Co., Ltd., average particle size 20 μm, purity 99.9%) was used and treated under the conditions shown in Table 1. Table 1 shows the results.

[0106] [Example 8-1], [Example 8-2] and [Comparative Example 8-1]

[0107] As sample 7, Pt powder (manufactured by Nilaco Corporation, average particle size 5 μm, purity 99.9%) was used and treated under the conditions shown in Table 1. Table 1 shows the results.

[0108] [Example 9-1], [Example 9-2] and [Comparative Example 9-1]

[0109] As sample 7, Fe powder (manufactured by Nilaco Corporation, average particle size 70 μm, purity 99%) was used and treated under the conditions shown in Table 1. Table 1 shows the results.

[0110] [Example 10-1], [Example 10-2] and [Comparative Example 10-1]

[0111] As sample 7, Co powder (manufactured by Merck, average particle size 2 μm, purity 99.8%) was used and treated under the conditions shown in Table 1. Table 1 shows the results.

[0112] [Example 11-1], [Example 11-2] and [Comparative Example 11-1]

[0113] As sample 7, Ni powder (manufactured by Nilaco Corporation, average particle size 50 μm, purity 99.9%) was used and processed under the conditions shown in Table 1. Table 1 shows the results.

[0114] [Comparative Example 12]

[0115] Using SF 6 NF 3 、SiF 4 CF 4 , CHF 3 Or they were mixed with NH 3A mixture of as an etching gas was used, and the metal removal process was performed in the same manner as in Example 1-1. No mass reduction was found when any etching gas was used. In addition, no mass reduction of Ir powder was found when the temperature conditions of the reaction process were changed from 30°C to 100°C or 0°C for treatment, or when the temperature conditions of the volatilization process were changed from 100°C to 50°C or 350°C. These results were all the same not only when Ir powder was used as sample 7, but also when powders of W, Se, Mo, Rh, Pd, Re, Pt, Fe, Co, and Ni were used.

[0116] [Reference Example 1-1], [Reference Example 1-2], [Reference Example 1-3], and [Reference Example 1-4]

[0117] As sample 7, SiO 2 The powder (manufactured by Maruta Corporation, average particle size 50 μm, purity 99.9%) was treated under the conditions shown in Table 1. Table 1 shows the results.

[0118] [Reference Example 2-1], [Reference Example 2-2], [Reference Example 2-3], and [Reference Example 2-4]

[0119] As sample 7, Si 3 N 4 The powder (manufactured by Ube Industries, Ltd., average particle size 50 μm, purity 99.9%) was treated under the conditions shown in Table 1. Table 1 shows the results.

[0120] As can be seen from Examples 1-1, 1-2, 1-3 and 1-4, BrF is used in the reaction step. 5 or IF 7 The etching gas is reacted at 0° C. or 30° C., and heated to 100° C. in a vacuum environment in a volatilization step, whereby Ir can be etched.

[0121] On the other hand, it can be seen from Comparative Example 1-1 that the use of F in the reaction step 2 When BrF was used as the etching gas, the etching of Ir did not proceed. 5 When only the reaction step was performed without performing the volatilization step as the etching gas, Ir could not be etched and the mass of the sample 7 increased.

[0122] In addition, from the results of Examples 1-5 to 1-12, it can be seen that even if p-BrF 5 or IF 7 Even in the case of a process gas mixed with an inert gas, Ir etching can be performed.

[0123] From Examples 2-1, 2-2, 4-1, 4-2, 5-1, 5-2, 7-1, 7-2, 8-1, and 8-2, it can be seen that in the reaction step, BrF 5 or IF 7 The etching gas is reacted at 30° C. and heated to 100° C. in a vacuum environment in a volatilization step, thereby enabling etching of W, Mo, Rh, Re, and Pt.

[0124] On the other hand, it can be seen from Comparative Examples 2-1, 4-1, 5-1, 7-1, and 8-1 that the use of F in the reaction step 2 In the case of the etching gas, etching of W, Mo, Rh, Re, and Pt did not proceed.

[0125] From Examples 3-1 and 3-2, it can be seen that in the reaction step, BrF 5 or IF 7 Se can be etched by reacting the etching gas at 30° C. and heating it to 50° C. in a vacuum environment in the volatilization step.

[0126] On the other hand, it can be seen from Comparative Example 3-1 that the use of F in the reaction step 2 In the case of the etching gas, Se etching did not proceed.

[0127] From Examples 6-1 and 6-2, it can be seen that BrF is used in the reaction step. 5 or IF 7 The etching gas is reacted at 30° C. and heated to 350° C. in a vacuum environment in a volatilization step, thereby enabling etching of Pd.

[0128] On the other hand, it can be seen from Comparative Example 6-1 that the use of F in the reaction step 2 In the case of the etching gas, etching of Pd did not proceed.

[0129] From Examples 9-1, 9-2, 10-1, 10-2, 11-1, and 11-2, it can be seen that BrF is used in the reaction step. 5 or IF 7 The etching gas is reacted at 100° C. and heated to 350° C. in a vacuum environment in a volatilization step, thereby enabling etching of Fe, Co, and Ni.

[0130] On the other hand, it can be seen from Comparative Examples 9-1, 10-1, and 11-1 that the use of F in the reaction step 2 In the case of the etching gas, etching of Fe, Co, and Ni did not proceed.

[0131] In addition, it can be seen from Reference Examples 1-1, 1-2, 2-1, and 2-2 that BrF 5 or IF 7 When the etching gas is reacted at 30°C, SiO 2 and Si 3 N 4 The etching was not performed.

[0132] Furthermore, it can be seen from Reference Examples 1-3, 1-4, 2-3, and 2-4 that even when BrF is used in the reaction step, 5 or IF 7 When the etching gas is reacted at 100°C, SiO 2 and Si 3 N 4 Only a small amount of etching was also performed.

[0133] It can be seen from this that if the metal removal process of each of the above embodiments is performed, SiO can be removed without etching. 2 and Si 3 N 4 Selectively etches Fe, Co, Ni, Se, Mo, Rh, Pd, W, Re, Ir, and Pt.

[0134] [Example 12-1], [Example 12-2] and [Comparative Example 13]

[0135] use Figure 1 The reaction device 1 was used to perform metal removal treatment, that is, etching, on the sample 7 of Example 12-1, Example 12-2 and Comparative Example 13. Figure 2 Sample 7 used in Example 12-1, Example 12-2, and Comparative Example 13 will be described.

[0136] A material (manufactured by KSTWORLD Co., Ltd.) in which a tungsten film 22 with a thickness of 1 μm was formed on a square silicon substrate 21 with a side length of 2 inches was prepared, and a rectangular silicon dioxide substrate 23 with a size of 1 inch×2 inches was bonded to the tungsten 22 using grease (DEMNUM GREASE L-200 manufactured by Daikin Industries, Ltd.) to prepare a sample 7. Figure 2 As shown, the silicon dioxide substrate 23 is bonded so as to cover approximately half of the tungsten film 22. The tungsten film 22 is an object to be removed, that is, an object to be etched, and the silicon dioxide substrate 23 is used as a resist.

[0137] Using the sample 7, etching was performed under the conditions shown in Table 2. In addition, except for the conditions shown in Table 2, it is the same as Example 1-5. After the etching is completed, the chamber is opened, the sample 7 is taken out, the silicon dioxide substrate 23 is removed from the taken out sample 7, and the bonding surface is washed with ethanol to remove the grease. Then, using an atomic force microscope VN-8010 manufactured by Keyence Corporation, the size of the step difference between the covered surface 22a of the tungsten film 22 that is covered by the silicon dioxide substrate 23 and is not etched, and the etching surface 22b of the tungsten film 22 that is not covered by the silicon dioxide substrate 23 and is etched is measured. The etching rate (nm / minute) of tungsten is calculated by dividing the size of the measured step difference (nm) by the etching time (minutes). The results are shown in Table 2.

[0138] The measurement conditions for the size of the step difference using an atomic force microscope are as follows.

[0139] Measuring pressure: atmospheric pressure (101.3kPa)

[0140] Measurement temperature: 28℃

[0141] Measurement atmosphere: In the air

[0142] Scanning range: width 80.0μm, height 20.0μm, angle 0°

[0143]

[0144] As can be seen from Examples 12-1 and 12-2, even when the object to be removed, ie, the object to be etched, is a film, etching proceeds without any problem. On the other hand, as can be seen from Comparative Example 13, when fluorine gas is used as the etching gas, etching hardly proceeds.

[0145] Description of Reference Numerals

[0146] 1. Reaction apparatus

[0147] 3 Chambers

[0148] 5 Stage

[0149] 7 Test Materials

[0150] 11 Gas inlet

[0151] 13 Gas outlet

[0152] 15. Pressure gauge

[0153] 21 Silicon substrate

[0154] 22 Tungsten film

[0155] 23. Silicon dioxide substrate

Claims

1. A metal removal method comprising a reaction step and a volatilization step, The reaction step brings the treatment gas containing the fluorine-containing interhalogen compound into contact with the metal-containing material containing the metal element, thereby generating a metal fluoride which is a reaction product of the fluorine-containing interhalogen compound and the metal element. The volatilization step heats the metal fluoride in an inert gas atmosphere or a vacuum environment to volatilize it. The metal element is at least one selected from iron, cobalt, nickel, selenium, molybdenum, rhodium, palladium, tungsten, rhenium, iridium and platinum.

2. The metal removal method according to claim 1, wherein the fluorine-containing interhalogen compound is at least one selected from the group consisting of chlorine monofluoride, bromine monofluoride, chlorine trifluoride, chlorine pentafluoride, bromine pentafluoride and iodine heptafluoride.

3. The metal removal method according to claim 1 or 2, wherein the processing gas contains at least one inert gas selected from nitrogen, helium, neon, argon, krypton and xenon. 4 . The metal removal method according to claim 1 , wherein a reaction temperature of the fluorine-containing interhalogen compound and the metal element in the reaction step is 0° C. or higher and 100° C. or lower. 5 . The metal removal method according to claim 1 , wherein a heating temperature of the metal fluoride in the volatilization step is higher than a reaction temperature of the fluorine-containing interhalogen compound and the metal element in the reaction step. 6 . The metal removal method according to claim 5 , wherein a heating temperature of the metal fluoride in the volatilization step is 50° C. or higher and 400° C. or lower. 7 . The metal removal method according to claim 1 , wherein in the reaction step, the processing gas is brought into contact with a silicon-containing material and the metal-containing material, the silicon-containing material containing at least one of silicon oxide and silicon nitride.

8. A dry etching method using the metal removal method according to any one of claims 1 to 7.

9. A method for manufacturing a semiconductor element, comprising a dry etching process, wherein the dry etching process uses the dry etching method described in claim 8 to remove at least a portion of the metal-containing layer from a semiconductor substrate having a metal-containing layer, wherein the metal-containing layer contains at least one metal element selected from iron, cobalt, nickel, selenium, molybdenum, rhodium, palladium, tungsten, rhenium, iridium and platinum.

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