Dry etching method, manufacturing method of semiconductor device, and cleaning method

Abstract

To provide a dry etching method capable of selectively etching an object to be etched containing at least one metal selected from titanium, indium, and tin at a sufficient etching rate without using plasma.SOLUTION: A dry etching method includes a dry etching step of bringing an etching gas containing a halogen fluoride, which is a compound of bromine or iodine and fluorine, into contact with a member 12 to be etched having an object to be etched, which is an object to be etched by the etching gas, and etching the object to be etched without using plasma. The etching target contains at least one metal selected from titanium, indium, and tin.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a dry etching method, a method for manufacturing a semiconductor device, and a cleaning method. [Background technology]

[0002] Materials containing metals such as titanium (Ti), indium (In), and tin (Sn) are sometimes used as hard masks or electrode materials for semiconductor devices. To use such metal-containing materials as semiconductor device materials, a technique for microfabricating the metal-containing materials into desired shapes is required. However, many of the metal-containing materials are difficult to etch because they have almost no vapor pressure. Therefore, conventionally, microfabrication using wet etching has been the mainstream method, in which materials containing the metal are removed by contacting them with a solution containing an oxidizing agent, a chelating agent, fluoride ions, etc. (see, for example, Patent Document 1). However, when wet etching is used as an etching process for semiconductor elements, there is a risk that parts of the semiconductor elements that should not be etched will also be etched, resulting in the loss of properties of the semiconductor elements.

[0003] Meanwhile, methods for removing semiconductor element materials from the surface of semiconductor elements or the inner surface of a chamber of a semiconductor element manufacturing apparatus by dry etching are known. For example, Patent Document 2 discloses a method for removing metal deposits that have accumulated on the inner surface of a chamber during processing for manufacturing semiconductor elements. The method disclosed in Patent Document 2 involves simultaneously supplying a halogen element gas other than fluorine gas and fluorine gas into a chamber of a semiconductor element manufacturing apparatus to generate a halogen fluoride in the chamber, and then contacting the metal deposit with an etching gas containing this halogen fluoride to remove the metal deposit. However, the method disclosed in Patent Document 2 has the problem that a high temperature is required to generate the halogen fluoride, which places a heavy load on the semiconductor device manufacturing equipment. Also, since the etching gas is a mixed gas of the halogen fluoride and unreacted halogen element gas, there is a risk that a sufficient etching rate cannot be obtained. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Special Publication No. 2008-536312 [Patent Document 2] Japanese Patent Application Laid-Open No. 2001-267241 Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present invention is to provide a dry etching method, a semiconductor element manufacturing method, and a cleaning method that can selectively etch an etching target containing at least one metal selected from titanium, indium, and tin at a sufficient etching rate without using plasma. [Means for solving the problem]

[0006] In order to solve the above problems, one aspect of the present invention is as follows [1] to

[11] . [1] A dry etching method comprising a dry etching step of contacting an etching gas containing a halogen fluoride, which is a compound of bromine or iodine and fluorine, with a member to be etched having an etching object that is the target of etching with the etching gas, and etching the etching object without using plasma, wherein the etching object contains at least one metal selected from titanium, indium, and tin.

[0007] [2] The dry etching method according to [1], wherein the halogen fluoride is at least one selected from the group consisting of bromine monofluoride, bromine trifluoride, bromine pentafluoride, iodine pentafluoride, and iodine heptafluoride. [3] The dry etching method according to [1] or [2], wherein the etching gas is a mixed gas containing the halogen fluoride and an inert gas.

[0008] [4] The dry etching method according to any one of [1] to [3], wherein the content of the halogen simple substance gas contained in the etching gas is less than 5% by volume. [5] The dry etching method according to any one of [1] to [4], wherein the dry etching step is carried out at a temperature of 40° C. or higher and 250° C. or lower. [6] The dry etching method according to any one of [1] to [4], wherein the dry etching step is carried out at a temperature of 80° C. or higher and 150° C. or lower. [7] The dry etching method according to any one of [1] to [6], wherein the dry etching step is carried out under a pressure condition of 1 Pa or more and 100 kPa or less.

[0009] [8] The member to be etched includes a non-etching object that is not a target for etching by the etching gas, and the etching object, the non-etching object comprises at least one selected from copper, nickel, cobalt, and photoresist; The dry etching method according to any one of [1] to [7], wherein the etching object is selectively etched relative to the non-etching object. [9] The dry etching method according to any one of [1] to [8], wherein the object to be etched is at least one selected from the group consisting of an elemental metal, an oxide of the metal, a nitride of the metal, an oxynitride of the metal, and an oxyfluoride of the metal.

[0010]

[10] A method for manufacturing a semiconductor element by using the dry etching method according to any one of [1] to [9], the member to be etched is a semiconductor substrate having the etching target, A method for manufacturing a semiconductor device, comprising a processing step of removing at least a part of the etching object from the semiconductor substrate by etching.

[0011]

[11] A cleaning method for cleaning an inner surface of a chamber of a semiconductor device manufacturing apparatus using the dry etching method according to any one of [1] to [9], the member to be etched is the chamber, the chamber has deposits on its inner surface that have been deposited during operation of the semiconductor device manufacturing apparatus, and the deposits are the etching target; a cleaning method comprising a cleaning step of removing the deposits from the inner surface of the chamber by etching. [Effects of the Invention]

[0012] According to the present invention, an etching target containing at least one metal element selected from titanium, indium, and tin can be selectively etched at a sufficient etching rate without using plasma. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a schematic diagram of an example of an etching apparatus for explaining an embodiment of a dry etching method according to the present invention. [Figure 2] FIG. 10 is a schematic diagram of another example of an etching apparatus for explaining an embodiment of a dry etching method according to the present invention. [Figure 3] FIG. 1 is a diagram illustrating test pieces used in Examples, Comparative Examples, and Reference Examples. DETAILED DESCRIPTION OF THE INVENTION

[0014] An embodiment of the present invention will be described below. Note that this embodiment is merely an example of the present invention, and the present invention is not limited to this embodiment. Furthermore, various modifications and improvements can be made to this embodiment, and such modifications and improvements can also be included in the present invention.

[0015] The dry etching method according to the present embodiment includes a dry etching step of contacting an etching gas containing a halogen fluoride, which is a compound of bromine (Br) or iodine (I) and fluorine (F), with a member to be etched, the member having an etching target to be etched by the etching gas, and etching the etching target without using plasma. The etching target contains at least one metal selected from titanium (Ti), indium (In), and tin (Sn).

[0016] When the etching gas is brought into contact with the object to be etched, the halogen fluoride in the etching gas reacts with the metal in the object to be etched to generate a fluoride of the metal. Because the fluoride of the metal is volatile, the volatilization of the fluoride of the metal progresses the etching of the object to be etched.

[0017] Therefore, the dry etching method according to this embodiment can selectively etch an etching target containing at least one metal selected from titanium, indium, and tin at a sufficient etching rate without using plasma. That is, the etching target can be selectively etched relative to a non-etching target that is not a target for etching with an etching gas. The non-etching target will be described in detail later.

[0018] Furthermore, according to the dry etching method of this embodiment, an object to be etched can be etched without using plasma, eliminating the need for an expensive plasma generator. Therefore, etching of an object to be etched can be performed at low cost. Furthermore, because no plasma is used, corrosion is less likely to occur in components constituting the etching apparatus (e.g., a chamber), piping connected to the etching apparatus, components constituting a semiconductor device manufacturing apparatus (described later) (e.g., a chamber), piping connected to the semiconductor device manufacturing apparatus (described later), and the like.

[0019] The dry etching method according to this embodiment can be used for manufacturing semiconductor devices and for cleaning the inner surfaces of chambers in semiconductor device manufacturing equipment. That is, the method for manufacturing a semiconductor element according to this embodiment is a method for manufacturing a semiconductor element using the dry etching method according to this embodiment, in which the member to be etched is a semiconductor substrate having the object to be etched, and the method includes a processing step of removing at least a portion of the object to be etched from the semiconductor substrate by etching.

[0020] An example of a method for manufacturing a semiconductor device according to this embodiment will be described. This manufacturing method includes a film formation step of forming a layer of an object to be etched on the surface of a semiconductor substrate, a mask formation step of forming a mask having a predetermined pattern on the layer of the object to be etched, and a processing step of etching the layer of the object to be etched on which the mask has been formed using the dry etching method according to this embodiment. The processing step removes the portions of the layer of the object to be etched that are not covered by the mask, thereby transferring the pattern to the layer of the object to be etched, thereby obtaining a semiconductor device.

[0021] The cleaning method according to the present embodiment is a cleaning method for cleaning the inner surface of a chamber of a semiconductor device manufacturing apparatus using the dry etching method according to the present embodiment, in which the member to be etched is the chamber. The chamber has deposits on its inner surface that have adhered during operation of the semiconductor device manufacturing apparatus, and these deposits are the etching target. The cleaning method according to the present embodiment includes a cleaning step of removing the deposits from the inner surface of the chamber by etching.

[0022] For example, during the film formation process and the processing process in the example of the semiconductor device manufacturing method according to the present embodiment described above, unwanted deposits made of the material to be etched may adhere to the inner surface of the chamber in which these film formation process and processing process are carried out. Therefore, if the cleaning process is carried out at one or both of the timings after the film formation process and the processing process are completed, the deposits can be removed from the inner surface of the chamber by etching.

[0023] The dry etching method, semiconductor device manufacturing method, and cleaning method according to the present embodiment will be described in further detail below. [Halogen fluorides] The type of halogen fluoride is not particularly limited as long as it is a compound of bromine or iodine and fluorine, but at least one selected from bromine monofluoride (BrF), bromine trifluoride (BrF), bromine pentafluoride (BrF), iodine pentafluoride (IF), and iodine heptafluoride (IF) is preferred. Among these halogen fluorides, at least one selected from bromine pentafluoride and iodine heptafluoride is more preferred from the viewpoints of ease of handling and availability.

[0024] [Etching gas] The etching gas is a gas containing a halogen fluoride. The etching gas may be a gas consisting of only a halogen fluoride, or may be a mixed gas containing a halogen fluoride and other gases. When the etching gas is a mixed gas containing a halogen fluoride and other gases, the content of the halogen fluoride contained in the etching gas is preferably 1% by volume or more, more preferably 5% by volume or more, and even more preferably 10% by volume or more, in order to etch the etching target at a sufficient etching rate.

[0025] When the etching gas is a mixed gas containing a halogen fluoride and other gases, an inert gas can be used as the other gas. That is, the etching gas may be a mixed gas containing a halogen fluoride and an inert gas. The inert gas can be at least one selected from nitrogen gas (N), helium (He), neon (Ne), argon (Ar), krypton (Kr), and xenon (Xe). The content of the inert gas contained in the etching gas is not particularly limited, but can be more than 0% by volume and not more than 90% by volume.

[0026] The etching gas may contain a halogen element gas, such as fluorine gas (F2), chlorine gas (Cl2), bromine gas (Br2), or iodine gas (I2). However, in order to etch the target material at a sufficient etching rate, it is preferable that the content of the halogen element gas contained in the etching gas be as low as possible. Specifically, the content of the halogen element gas contained in the etching gas is preferably less than 5% by volume, more preferably 1% by volume or less, and even more preferably 1000 ppm by volume or less.

[0027] [Temperature conditions for dry etching process] The temperature conditions for the dry etching step in the dry etching method according to this embodiment are not particularly limited as long as the halogen fluoride can exist in a gaseous state under the pressure during etching, but are preferably 40° C. or higher and 250° C. or lower, more preferably 45° C. or higher and lower than 250° C., and even more preferably 50° C. or higher and 200° C. or lower. Here, the temperature in the temperature conditions refers to the temperature of the member to be etched, and the temperature of the stage in the chamber of the etching apparatus can also be used.

[0028] If the temperature condition is 40° C. or higher, the halogen fluoride can exist in a gaseous state and the etching rate of the etching target is likely to be higher. On the other hand, if the temperature condition is 250° C. or lower, there are advantages such as etching can be performed without requiring excessive time and energy, the load on the etching equipment and the semiconductor device manufacturing equipment is small, and etching of parts that should not be etched (for example, non-etching targets described later) can be suppressed.

[0029] [Pressure conditions for the dry etching process] The pressure conditions for the dry etching step in the dry etching method according to this embodiment are not particularly limited as long as the halogen fluoride can exist in a gaseous state at the pressure during etching, but are preferably from 1 Pa to 100 kPa, more preferably from 1 kPa to 90 kPa, even more preferably from 2 kPa to 80 kPa, and particularly preferably from 5 kPa to 50 kPa. The flow rate of the etching gas may be appropriately set so as to maintain a constant pressure in the chamber, depending on the size of the chamber and the capacity of the exhaust equipment for reducing the pressure inside the chamber.

[0030] [Object to be etched] The etching target to be etched by the etching gas contains at least one metal selected from titanium, indium, and tin, and may be any of the metals alone or in the form of a compound of the metal, or may be a mixture containing at least one of the metals alone and the compound of the metal.

[0031] Examples of mixtures containing at least one of the metal simple substance and the metal compound include alloys of the metal with another metal, mixtures of at least one of the metal simple substance and the metal compound with other materials, mixtures of at least one of the metal simple substance and the metal compound with impurities, etc. These mixtures preferably contain at least 10 mol %, more preferably at least 20 mol %, and even more preferably at least 30 mol % of the metal simple substance and the metal compound in total.

[0032] Examples of the metal compounds include oxides, nitrides, oxynitrides, and oxyfluorides of the metal. The metal oxides, nitrides, oxynitrides, and oxyfluorides of the metal respectively refer to compounds consisting of the metal and an oxygen atom (O), compounds consisting of the metal and a nitrogen atom (N), compounds consisting of the metal, an oxygen atom, and a nitrogen atom, and compounds consisting of the metal, an oxygen atom, and a fluorine atom. The form of the metal oxides, nitrides, oxynitrides, and oxyfluorides of the metal is not particularly limited and may be, for example, a film, foil, powder, particle, or block.

[0033] The ratio of the metal to oxygen atoms, nitrogen atoms, and fluorine atoms in the compound of the metal is not particularly limited. However, the oxide of the metal may be, for example, x O y(M is at least one metal selected from titanium, indium, and tin, and x and y are each independently an integer of 1 or more), and the compound contains preferably 10 mol % or more, more preferably 15 mol % or more, and even more preferably 20 mol % or more of the metal. Specific examples include compounds represented by MO, MO, MO, MO, MO, MO, MO, and MO.

[0034] The nitride of the metal is, for example, M a N b (M is at least one metal selected from titanium, indium, and tin, and a and b are each independently an integer of 1 or more), and the compound contains preferably 10 mol % or more, more preferably 15 mol % or more, and even more preferably 20 mol % or more of the metal. Specifically, M N, M N, M N 2, M N 4, M N, M 7 N 3, M 16 Examples of compounds include those represented by N2.

[0035] The metal oxynitride may be, for example, M c N d O e (M is at least one metal selected from titanium, indium, and tin, and c, d, and e are each independently an integer of 1 or more), and the compound contains preferably 10 mol % or more, more preferably 15 mol % or more, and even more preferably 20 mol % or more of the metal.

[0036] The metal oxyfluoride is, for example, M f F g O h (wherein M is at least one metal selected from titanium, indium, and tin, and f, g, and h are each independently an integer of 1 or more), and the compound contains preferably 10 mol % or more, more preferably 15 mol % or more, and even more preferably 20 mol % or more of the metal.

[0037] The halogen fluoride in the etching gas, for example, bromine pentafluoride gas, reacts with an etching target containing at least one metal selected from titanium, indium, and tin at a predetermined reaction temperature to produce a reaction product that is presumed to be a metal fluoride or the like. The presumed structure of the metal fluoride varies depending on the combination of the halogen fluoride and the etching target, but for example, M q F r and M q O s F t Here, M is at least one metal selected from titanium, indium, and tin, and q, r, s, and t are each independently an integer of 1 or greater. Metal fluorides have a higher vapor pressure than the metal itself, its oxide, its nitride, its oxynitride, and the like, and are therefore volatilized and removed under the temperature and pressure conditions of etching.

[0038] [Objects not to be etched] The non-etching target having at least one selected from copper, nickel, cobalt, and photoresist reacts very slowly with halogen fluorides, or the vapor pressure of the reaction product generated by the reaction with halogen fluorides is low, so etching hardly progresses.

[0039] Therefore, when an etching target member having an etching target and a non-etching target is etched using the dry etching method according to this embodiment, the etching target can be selectively etched relative to the non-etching target. Therefore, the etching method according to this embodiment can be used to process the etching target into a predetermined shape (e.g., process a film-like etching target of the etching target member to a predetermined film thickness) using a patterned non-etching target as a mask, and is therefore suitable for use in the manufacture of semiconductor devices. Furthermore, because the non-etching target is not etched, etching of portions of the semiconductor device that should not be etched can be suppressed, and the loss of characteristics of the semiconductor device due to etching can be prevented.

[0040] Photoresists refer to photosensitive compositions whose physical properties, including solubility, change when exposed to light or electron beams. Examples include photoresists for g-line, h-line, i-line, KrF, ArF, F2, and EUV. The composition of the photoresist is not particularly limited as long as it is one commonly used in semiconductor manufacturing processes. Examples include compositions containing a polymer synthesized from at least one monomer selected from linear olefins, cyclic olefins, styrene, vinylphenol, (meth)acrylic acid, (meth)acrylate, epoxy, melamine, and glycol. Note that (meth)acrylic acid refers to either or both of acrylic acid and methacrylic acid, and (meth)acrylate refers to either or both of acrylate and methacrylate.

[0041] Next, an example of the configuration of an etching apparatus capable of carrying out the etching method according to this embodiment and an example of a dry etching method using the etching apparatus will be described with reference to Figure 1. The etching apparatus in Figure 1 is a plasmaless etching apparatus that does not use plasma. First, the etching apparatus in Figure 1 will be described.

[0042] The etching apparatus of FIG. 1 includes a chamber 10 in which etching is performed, a stage 11 that supports a member 12 to be etched inside the chamber 10, a thermometer 14 that measures the temperature of the member 12 to be etched, an exhaust pipe 13 that exhausts gas from inside the chamber 10, a vacuum pump 15 that is connected to the exhaust pipe 13 and reduces the pressure inside the chamber 10, and a pressure gauge 16 that measures the pressure inside the chamber 10.

[0043] 1 also includes an etching gas supply unit that supplies an etching gas into the chamber 10. This etching gas supply unit includes a halogen fluoride gas supply unit 1 that supplies a halogen fluoride gas, an inert gas supply unit 2 that supplies an inert gas, a halogen fluoride gas supply pipe 5 that connects the halogen fluoride gas supply unit 1 and the chamber 10, and an inert gas supply pipe 6 that connects the inert gas supply unit 2 to an intermediate portion of the halogen fluoride gas supply pipe 5.

[0044] Furthermore, a pressure gauge 7 for measuring the pressure of the halogen fluoride gas and a halogen fluoride gas flow rate control device 3 for controlling the flow rate of the halogen fluoride gas are provided in the halogen fluoride gas supply pipe 5. Furthermore, an inert gas pressure control device 8 for controlling the pressure of the inert gas and an inert gas flow rate control device 4 for controlling the flow rate of the inert gas are provided in the inert gas supply pipe 6.

[0045] When halogen fluoride gas is supplied to the chamber 10 as an etching gas, the halogen fluoride gas is sent from the halogen fluoride gas supply unit 1 to the halogen fluoride gas supply pipe 5, and the halogen fluoride gas is supplied to the chamber 10 via the halogen fluoride gas supply pipe 5.

[0046] Furthermore, when a mixed gas of halogen fluoride gas and inert gas is supplied as the etching gas, halogen fluoride gas is fed from halogen fluoride gas supply unit 1 to halogen fluoride gas supply pipe 5, and inert gas is fed from inert gas supply unit 2 to halogen fluoride gas supply pipe 5 via inert gas supply pipe 6. As a result, the halogen fluoride gas and the inert gas are mixed in the middle of halogen fluoride gas supply pipe 5 to form a mixed gas, and this mixed gas is supplied to chamber 10 via halogen fluoride gas supply pipe 5.

[0047] The configurations of the halogen fluoride gas supply unit 1 and the inert gas supply unit 2 are not particularly limited, and may be, for example, a bomb or a cylinder. Furthermore, the halogen fluoride gas flow rate control device 3 and the inert gas flow rate control device 4 may be, for example, a mass flow controller or a flow meter.

[0048] When the etching gas is supplied to the chamber 10, it is preferable to supply the etching gas while maintaining the supply pressure of the etching gas (i.e., the value of the pressure gauge 7 in FIG. 1) at a predetermined value. That is, the supply pressure of the etching gas is preferably 10 Pa or more and 1.0 MPa or less, more preferably 100 Pa or more and 0.5 MPa or less, and even more preferably 500 Pa or more and 0.3 MPa or less. When the supply pressure of the etching gas is within the above range, the etching gas is smoothly supplied to the chamber 10, and the load on the components of the etching apparatus of FIG. 1 (e.g., the various devices and piping) is small.

[0049] Furthermore, from the viewpoint of uniformly etching the surface of the member to be etched 12, the pressure of the etching gas supplied into the chamber 10 is preferably from 1 Pa to 100 kPa, more preferably from 1 kPa to 90 kPa, even more preferably from 2 kPa to 80 kPa, and particularly preferably from 5 kPa to 50 kPa. If the pressure of the etching gas in the chamber 10 is within the above range, the volatilization of the metal fluoride proceeds smoothly, thereby obtaining a sufficient etching rate and easily increasing the etching rate ratio to the non-etched object, i.e., the etching selectivity ratio.

[0050] The pressure in the chamber 10 before the etching gas is supplied is not particularly limited as long as it is equal to or lower than the supply pressure of the etching gas. For example, -5 The pressure is preferably 1 Pa or more but less than 100 kPa, and more preferably 1 Pa or more but less than 80 kPa.

[0051] The differential pressure between the supply pressure of the etching gas and the pressure inside the chamber 10 before the etching gas is supplied is preferably 1.0 MPa or less, more preferably 0.5 MPa or less, and even more preferably 0.3 MPa or less. If the differential pressure is within the above range, the etching gas is likely to be smoothly supplied to the chamber 10.

[0052] The etching gas is preferably supplied while maintaining the temperature of the etching gas at a predetermined value when being supplied to the chamber 10. That is, the supply temperature of the etching gas is preferably 10°C or higher and 250°C or lower. The temperature of the member to be etched 12 during etching is preferably 40°C or higher and 250°C or lower, more preferably 45°C or higher and lower than 250°C, and even more preferably 50°C or higher and 200°C or lower. Depending on the type of material not to be etched, a temperature of 80°C or higher and 150°C or lower may be preferable. Within this temperature range, etching of the material to be etched in the member to be etched 12 proceeds smoothly, the load on the etching equipment is small, and the life of the etching equipment is likely to be extended.

[0053] The etching processing time (hereinafter sometimes referred to as "etching time") can be set arbitrarily depending on the degree to which the etching target of the member to be etched 12 is desired to be etched, but considering the production efficiency of the semiconductor device manufacturing process, it is preferably within 60 minutes, more preferably within 40 minutes, and even more preferably within 30 minutes. Note that the etching processing time refers to the time from when the etching gas is introduced into the chamber 10 until the etching gas inside the chamber 10 is exhausted to complete the etching.

[0054] The dry etching method according to this embodiment can be performed using a general plasma-less etching apparatus used in the semiconductor device manufacturing process, such as the etching apparatus shown in FIG. 1, and the configuration of the etching apparatus that can be used is not particularly limited. For example, the positional relationship between the halogen fluoride gas supply pipe 5 and the member to be etched 12 is not particularly limited as long as it allows the etching gas to come into contact with the member to be etched 12. Furthermore, the configuration of the temperature adjustment mechanism of the chamber 10 is also sufficient as long as it is possible to adjust the temperature of the member to be etched 12 to a desired temperature, so the temperature adjustment mechanism may be directly provided on the stage 11, or an external temperature adjuster may be used to heat or cool the chamber 10 from outside the chamber 10.

[0055] The material of the etching apparatus shown in FIG. 1 is not particularly limited as long as it is corrosion-resistant to the halogen fluoride used and can be depressurized to a predetermined pressure. For example, metals such as nickel, nickel-based alloys, aluminum, stainless steel, and platinum, ceramics such as alumina, and fluororesins can be used for the parts that come into contact with the etching gas. Specific examples of nickel-based alloys include Inconel (registered trademark), Hastelloy (registered trademark), and Monel (registered trademark). Examples of fluororesins include polytetrafluoroethylene (PTFE), polychlorotrifluoroethylene (PCTFE), tetrafluoroethylene-perfluoroalkoxyethylene copolymer (PFA), polyvinylidene fluoride (PVDF), Teflon (registered trademark), Viton (registered trademark), and Kalrez (registered trademark).

[0056] Furthermore, as mentioned above, the etching gas may contain a halogen elemental gas as long as the concentration is less than 5% by volume. When etching is performed using an etching gas containing a halogen elemental gas, for example, an etching apparatus shown in Fig. 2 can be used. The etching apparatus shown in Fig. 2 will now be described. However, since the configuration of the etching apparatus shown in Fig. 2 and the etching method using the etching apparatus shown in Fig. 2 are roughly similar to those of the etching apparatus shown in Fig. 1, a description of the similar parts will be omitted and only the differences will be described.

[0057] The etching apparatus of Fig. 2 includes an etching gas supply unit that supplies an etching gas to the inside of a chamber 10. The etching gas supply unit of the etching apparatus of Fig. 2 includes a halogen fluoride gas supply unit 1 that supplies a halogen fluoride gas, an inert gas supply unit 2 that supplies an inert gas, a halogen elemental gas supply unit 17 that supplies a halogen elemental gas, a halogen fluoride gas supply pipe 5 that connects the halogen fluoride gas supply unit 1 to the chamber 10, an inert gas supply pipe 6 that connects the inert gas supply unit 2 to an intermediate portion of the halogen fluoride gas supply pipe 5, and a halogen elemental gas supply pipe 19 that connects the halogen elemental gas supply unit 17 to an intermediate portion of the inert gas supply pipe 6. A halogen elemental gas flow rate control device 18 that controls the flow rate of the halogen elemental gas is provided in the halogen elemental gas supply pipe 19.

[0058] When a mixed gas of halogen fluoride gas and simple halogen gas is supplied as the etching gas, halogen fluoride gas is sent from halogen fluoride gas supply unit 1 to halogen fluoride gas supply pipe 5, and simple halogen gas is sent from halogen fluoride gas supply unit 17 to halogen fluoride gas supply pipe 5 via simple halogen gas supply pipe 19 and inert gas supply pipe 6. As a result, the halogen fluoride gas and simple halogen gas are mixed in the middle of halogen fluoride gas supply pipe 5 to form a mixed gas, and this mixed gas is supplied to chamber 10 via halogen fluoride gas supply pipe 5.

[0059] Similarly, when a mixed gas of halogen fluoride gas, inert gas, and halogen elemental gas is supplied as the etching gas, halogen fluoride gas is sent from halogen fluoride gas supply unit 1 to halogen fluoride gas supply pipe 5, and inert gas is sent from inert gas supply unit 2 to halogen fluoride gas supply pipe 5 via inert gas supply pipe 6, and further, halogen elemental gas is sent from halogen elemental gas supply unit 17 to halogen fluoride gas supply pipe 5 via halogen elemental gas supply pipe 19 and inert gas supply pipe 6. As a result, halogen fluoride gas, inert gas, and halogen elemental gas are mixed in the middle of halogen fluoride gas supply pipe 5 to form a mixed gas, and this mixed gas is supplied to chamber 10 via halogen fluoride gas supply pipe 5. The configuration of the halogen simple substance gas supply unit 17 is not particularly limited, and may be, for example, a bomb or cylinder. Furthermore, the halogen simple substance gas flow rate control device 18 may be, for example, a mass flow controller or a flow meter. [Example]

[0060] The present invention will be described in more detail below with reference to Examples, Comparative Examples, and Reference Examples. The purity of the bromine pentafluoride and iodine heptafluoride used in the following Examples, Comparative Examples, and Reference Examples was analyzed using a Fourier transform infrared spectrophotometer Nicolet iS5 manufactured by Thermo Fisher Scientific and a double beam spectrophotometer U-2900 manufactured by Hitachi High-Tech Science Corporation, and it was confirmed that the purity of each was 99% by mass or more.

[0061] (Example 1-1) An etching target was etched using an etching apparatus having substantially the same configuration as the etching apparatus shown in Fig. 1. The test piece (member to be etched) used in Example 1-1 will be described with reference to Fig. 3.

[0062] A 517-nm-thick titanium oxide (TiO2) film 22 was formed on a 2-inch square silicon substrate 21 (manufactured by KST World Co., Ltd.), and a 1-inch by 2-inch rectangular nickel substrate 23 was bonded to the titanium oxide film 22 using grease (Demnum Grease L-200 manufactured by Daikin Industries, Ltd.) to form a test specimen. The nickel substrate 23 was bonded so as to cover approximately half of the titanium oxide film 22, as shown in Figure 3.

[0063] The test piece was placed on a stage inside the chamber of the etching apparatus, and the temperature of the stage was raised to 150°C. Next, bromine pentafluoride gas at a flow rate of 50 mL / min and argon at a flow rate of 450 mL / min were mixed to form a mixed gas, which was used as the etching gas. This etching gas was then supplied into the chamber at a flow rate of 500 mL / min and circulated for 10 minutes to perform etching. As a result, the exposed portions of the titanium oxide film 22 that were not covered by the nickel substrate 23 were etched. The pressure inside the chamber during the flow of the etching gas was 10 kPa, and the partial pressure of the bromine pentafluoride gas was 1 kPa. After the flow of the etching gas was completed, the heating of the stage was stopped, and the inside of the chamber was replaced with argon.

[0064] After etching was completed, the chamber was opened and the test piece was removed. The nickel substrate 23 was removed from the test piece, and the adhesive surface was washed with ethanol to remove grease. Then, using an atomic force microscope VN-8010 manufactured by Keyence Corporation, the height of the step between the cover surface 22a of the titanium oxide film 22 that was covered by the nickel substrate 23 and not etched and the etched surface 22b of the titanium oxide film 22 that was not covered by the nickel substrate 23 and was etched was measured. The measured height of the step (nm) was divided by the etching time (min) to calculate the etching rate (nm / min). The results are shown in Table 1.

[0065] The conditions for measuring the size of the step using an atomic force microscope are as follows. Measurement pressure: atmospheric pressure (101.3 kPa) Measurement temperature: 28℃ Measurement atmosphere: Air Scanning range: width 80.0 μm, height 20.0 μm, angle 0°

[0066] [Table 1]

[0067] (Example 1-2) The etching rate of the titanium oxide was calculated in the same manner as in Example 1-1, except that the halogen fluoride was iodine heptafluoride and the etching gas was a mixture of iodine heptafluoride gas at a flow rate of 50 mL / min and argon gas at a flow rate of 450 mL / min. The results are shown in Table 1. (Examples 1-3) The test piece was etched in the same manner as in Example 1-1, except that the stage temperature was set to 50° C., and the etching rate of titanium oxide was calculated. The results are shown in Table 1.

[0068] (Examples 1-4) The test piece was etched in the same manner as in Example 1-1, except that the halogen fluoride was iodine heptafluoride, a mixed gas of iodine heptafluoride gas at a flow rate of 50 mL / min and argon at a flow rate of 450 mL / min was used as the etching gas, and the stage temperature was 50° C. The etching rate of titanium oxide was calculated. The results are shown in Table 1. (Examples 1-5) Test pieces were etched in the same manner as in Example 1-1, except that etching was performed using an etching apparatus having a configuration similar to that of the etching apparatus shown in Figure 2 and an etching gas containing a simple halogen gas, and the etching rate of titanium oxide was calculated. The results are shown in Table 1. The etching gas used was a mixed gas of bromine pentafluoride gas at a flow rate of 50 mL / min, fluorine gas (F2 gas) at a flow rate of 25 mL / min, and argon at a flow rate of 425 mL / min.

[0069] (Examples 1 to 6) The etching rate of the titanium oxide was calculated in the same manner as in Example 1-5, except that the etching gas was a mixture of bromine pentafluoride gas at a flow rate of 50 mL / min, bromine gas at a flow rate of 25 mL / min, and argon at a flow rate of 425 mL / min. The results are shown in Table 1. (Examples 1-7) The etching rate of the titanium oxide was calculated in the same manner as in Example 1-5, except that the etching gas was a mixture of iodine heptafluoride gas at a flow rate of 50 mL / min, iodine gas at a flow rate of 25 mL / min, and argon gas at a flow rate of 450 mL / min. The results are shown in Table 1.

[0070] (Comparative Example 1-1) The test piece was etched in the same manner as in Example 1-1, except that a mixed gas of fluorine gas (F2 gas) at a flow rate of 50 mL / min and argon at a flow rate of 450 mL / min was used as the etching gas, and the etching rate of titanium oxide was calculated. The results are shown in Table 1.

[0071] Example 2-1 Test pieces were prepared in the same manner as in Example 1-1, except that a 500 nm-thick titanium nitride (TiN) film (manufactured by KST World Co., Ltd.) was formed on a silicon substrate 21 instead of the titanium oxide film 22 (see FIG. 3). The test pieces were then etched in the same manner as in Example 1-1, except that the stage temperature was set to 130°C, and the etching rate of titanium nitride was calculated. The results are shown in Table 2.

[0072] [Table 2]

[0073] (Example 2-2) The etching rate of titanium nitride was calculated in the same manner as in Example 2-1, except that the halogen fluoride was iodine heptafluoride and the etching gas was a mixture of iodine heptafluoride gas at a flow rate of 50 mL / min and argon gas at a flow rate of 450 mL / min. The results are shown in Table 2. (Example 2-3) The test piece was etched in the same manner as in Example 2-1, except that the pressure inside the chamber was set to 3 kPa, and the etching rate of titanium nitride was calculated. The results are shown in Table 2.

[0074] (Examples 2-4) The test piece was etched in the same manner as in Example 2-2, except that the pressure inside the chamber was set to 3 kPa, and the etching rate of titanium nitride was calculated. The results are shown in Table 2. (Examples 2-5) The test piece was etched in the same manner as in Example 2-1, except that the pressure inside the chamber was set to 50 kPa, and the etching rate of titanium nitride was calculated. The results are shown in Table 2. (Examples 2-6) The test piece was etched in the same manner as in Example 2-2, except that the pressure inside the chamber was set to 50 kPa, and the etching rate of titanium nitride was calculated. The results are shown in Table 2.

[0075] (Comparative Example 2-1) The etching rate of titanium nitride was calculated in the same manner as in Example 2-1, except that the etching gas was a mixture of fluorine gas (F2 gas) at a flow rate of 50 mL / min and argon at a flow rate of 450 mL / min. The results are shown in Table 2.

[0076] Example 3-1 A 500 nm thick copper (Cu) film was formed on a 2-inch square silicon substrate to prepare a test piece. The test piece with this copper film and the test piece used in Example 2-1 were both used as the etched members, and the test pieces were etched in the same manner as in Example 2-1, except that these two test pieces were placed side by side on a stage inside the chamber. The etching rates of the titanium nitride, which was the etched object, and the copper, which was the non-etched object, were calculated. The results are shown in Table 3.

[0077] [Table 3]

[0078] (Example 3-2) The etching rates of titanium nitride and copper were calculated in the same manner as in Example 3-1, except that the halogen fluoride was iodine heptafluoride and the etching gas was a mixture of iodine heptafluoride gas at a flow rate of 50 mL / min and argon gas at a flow rate of 450 mL / min. The results are shown in Table 3. (Example 3-3) A test piece was prepared by depositing a 500 nm thick nickel (Ni) film on a 2-inch square silicon substrate. The test piece with this nickel film and the test piece used in Example 2-1 were both used as the etched members, and the test pieces were etched in the same manner as in Example 2-1, except that these two test pieces were placed side by side on a stage inside the chamber. The etching rates of the titanium nitride, which was the etched object, and the nickel, which was the non-etched object, were calculated. The results are shown in Table 3.

[0079] (Examples 3-4) The etching rates of titanium nitride and nickel were calculated in the same manner as in Example 3-3, except that the halogen fluoride was iodine heptafluoride and the etching gas was a mixture of iodine heptafluoride gas at a flow rate of 50 mL / min and argon gas at a flow rate of 450 mL / min. The results are shown in Table 3. (Examples 3-5) A test piece was prepared by depositing a 500 nm thick cobalt (Co) film on a 2-inch square silicon substrate. The test piece with this cobalt film and the test piece used in Example 2-1 were both used as the etched members, and the test pieces were etched in the same manner as in Example 2-1, except that these two test pieces were placed side by side on a stage inside the chamber. The etching rates of the titanium nitride, which was the etched object, and the cobalt, which was the non-etched object, were calculated. The results are shown in Table 3.

[0080] (Examples 3-6) The etching rates of titanium nitride and cobalt were calculated in the same manner as in Example 3-5, except that the halogen fluoride was iodine heptafluoride and the etching gas was a mixture of iodine heptafluoride gas at a flow rate of 50 mL / min and argon gas at a flow rate of 450 mL / min. The results are shown in Table 3. (Examples 3-7) A photoresist (TSCR (registered trademark) manufactured by Tokyo Ohka Kogyo Co., Ltd.) was applied to a square silicon substrate with sides measuring 2 inches, and then exposed and cured to form a photoresist film with a thickness of 1000 nm, which was used as a test piece. The test piece with this photoresist film and the test piece used in Example 2-1 were both used as the etched members, and the test pieces were etched in the same manner as in Example 2-1, except that these two test pieces were placed side by side on a stage inside the chamber. The etching rates of the titanium nitride, which was the etched object, and the photoresist, which was the non-etched object, were calculated. The results are shown in Table 3.

[0081] (Examples 3-8) The etching rates of the titanium nitride and the photoresist were calculated in the same manner as in Example 3-7, except that the halogen fluoride was iodine heptafluoride and the etching gas was a mixture of iodine heptafluoride gas at a flow rate of 50 mL / min and argon gas at a flow rate of 450 mL / min. The results are shown in Table 3.

[0082] (Comparative Example 3-1) The etching rates of titanium nitride and copper were calculated in the same manner as in Example 3-1, except that the etching gas was a mixture of fluorine gas at a flow rate of 50 mL / min and argon at a flow rate of 450 mL / min. The results are shown in Table 3. (Comparative Example 3-2) The etching rates of titanium nitride and nickel were calculated in the same manner as in Example 3-3, except that the etching gas was a mixture of fluorine gas at a flow rate of 50 mL / min and argon at a flow rate of 450 mL / min. The results are shown in Table 3.

[0083] (Comparative Example 3-3) The etching rates of titanium nitride and cobalt were calculated in the same manner as in Example 3-5, except that the etching gas was a mixture of fluorine gas at a flow rate of 50 mL / min and argon at a flow rate of 450 mL / min. The results are shown in Table 3. (Comparative Example 3-4) The test pieces were etched in the same manner as in Example 3-7, except that a mixed gas of fluorine gas at a flow rate of 50 mL / min and argon at a flow rate of 450 mL / min was used as the etching gas, and the etching rates of titanium nitride and photoresist were calculated. The results are shown in Table 3.

[0084] Example 4-1 Test pieces were prepared in the same manner as in Example 1-1, except that a 500 nm-thick titanium oxynitride film (manufactured by KST World Co., Ltd.) was formed on a silicon substrate 21 instead of the titanium oxide film 22 (see FIG. 3). The test pieces were then etched in the same manner as in Example 1-1, except that the stage temperature was set to 100°C, and the etching rate of the titanium oxynitride was calculated. The results are shown in Table 4.

[0085] [Table 4]

[0086] (Example 4-2) The etching rate of the titanium oxynitride was calculated in the same manner as in Example 4-1, except that the halogen fluoride was iodine heptafluoride and the etching gas was a mixture of iodine heptafluoride gas at a flow rate of 50 mL / min and argon gas at a flow rate of 450 mL / min. The results are shown in Table 4.

[0087] (Comparative Example 4-1) The test pieces were etched in the same manner as in Example 4-1, except that a mixed gas of fluorine gas at a flow rate of 50 mL / min and argon at a flow rate of 450 mL / min was used as the etching gas, and the etching rate of titanium oxynitride was calculated. The results are shown in Table 4.

[0088] (Example 5-1) Test pieces were prepared in the same manner as in Example 1-1 (see FIG. 3), except that a 500 nm-thick titanium oxyfluoride film (manufactured by KST World Co., Ltd.) was formed on a silicon substrate 21 instead of the titanium oxide film 22. The test pieces were then etched in the same manner as in Example 1-1, except that the stage temperature was set to 100°C, and the etching rate of the titanium oxyfluoride was calculated. The results are shown in Table 4. (Example 5-2) The etching rate of the titanium oxyfluoride was calculated in the same manner as in Example 5-1, except that the halogen fluoride was iodine heptafluoride and the etching gas was a mixture of iodine heptafluoride gas at a flow rate of 50 mL / min and argon gas at a flow rate of 450 mL / min. The results are shown in Table 4.

[0089] (Comparative Example 5-1) The test pieces were etched in the same manner as in Example 5-1, except that a mixed gas of fluorine gas at a flow rate of 50 mL / min and argon at a flow rate of 450 mL / min was used as the etching gas, and the etching rate of titanium oxyfluoride was calculated. The results are shown in Table 4.

[0090] Example 6-1 Test pieces were prepared in the same manner as in Example 1-1, except that a 500 nm-thick titanium (Ti) film (manufactured by KST World Co., Ltd.) was formed on a silicon substrate 21 instead of the titanium oxide film 22 (see FIG. 3). The test pieces were then etched in the same manner as in Example 1-1, except that the stage temperature was set to 80°C, and the titanium etching rate was calculated. The results are shown in Table 4. (Example 6-2) The etching rate of the titanium was calculated in the same manner as in Example 6-1, except that the halogen fluoride was iodine heptafluoride and the etching gas was a mixture of iodine heptafluoride gas at a flow rate of 50 mL / min and argon gas at a flow rate of 450 mL / min. The results are shown in Table 4.

[0091] (Comparative Example 6-1) The test pieces were etched in the same manner as in Example 6-1, except that a mixed gas of fluorine gas at a flow rate of 50 mL / min and argon at a flow rate of 450 mL / min was used as the etching gas, and the etching rate of titanium was calculated. The results are shown in Table 4.

[0092] Example 7-1 Test pieces were prepared in the same manner as in Example 1-1, except that a 500 nm-thick tin oxide (SnO) film (manufactured by KST World Co., Ltd.) was formed on a silicon substrate 21 instead of the titanium oxide film 22 (see FIG. 3). The test pieces were then etched in the same manner as in Example 1-1, except that the stage temperature was set to 160°C, and the etching rate of the tin oxide was calculated. The results are shown in Table 5.

[0093] [Table 5]

[0094] (Example 7-2) The etching rate of the tin oxide was calculated in the same manner as in Example 7-1, except that the halogen fluoride was iodine heptafluoride and the etching gas was a mixture of iodine heptafluoride gas at a flow rate of 50 mL / min and argon gas at a flow rate of 450 mL / min. The results are shown in Table 5.

[0095] (Example 7-3) The test piece was etched in the same manner as in Example 7-1, except that the stage temperature was set to 250° C., and the etching rate of tin oxide was calculated. The results are shown in Table 5. (Example 7-4) The test piece was etched in the same manner as in Example 7-2, except that the stage temperature was set to 250° C., and the etching rate of tin oxide was calculated. The results are shown in Table 5.

[0096] (Comparative Example 7-1) The test pieces were etched in the same manner as in Example 7-3, except that a mixed gas of fluorine gas at a flow rate of 50 mL / min and argon at a flow rate of 450 mL / min was used as the etching gas, and the etching rate of tin oxide was calculated. The results are shown in Table 4.

[0097] Example 8-1 Test pieces were prepared in the same manner as in Example 1-1, except that a 500 nm thick indium oxide (In2O3) film (manufactured by KST World Co., Ltd.) was formed on a silicon substrate 21 instead of the titanium oxide film 22 (see FIG. 3). The test pieces were then etched in the same manner as in Example 1-1, except that the stage temperature was set to 160°C, and the etching rate of indium oxide was calculated. The results are shown in Table 5. (Example 8-2) The etching rate of the indium oxide was calculated in the same manner as in Example 8-1, except that the halogen fluoride was iodine heptafluoride and the etching gas was a mixture of iodine heptafluoride gas at a flow rate of 50 mL / min and argon gas at a flow rate of 450 mL / min. The results are shown in Table 5.

[0098] (Comparative Example 8-1) The test pieces were etched in the same manner as in Example 8-1, except that a mixed gas of fluorine gas at a flow rate of 50 mL / min and argon at a flow rate of 450 mL / min was used as the etching gas, and the etching rate of indium oxide was calculated. The results are shown in Table 5.

[0099] (Example 9-1) Test pieces were prepared in the same manner as in Example 1-1 (see FIG. 3), except that a 500 nm thick indium tin oxide film (manufactured by KST World Co., Ltd.) was formed on a silicon substrate 21 instead of the titanium oxide film 22. The test pieces were then etched in the same manner as in Example 1-1, except that the stage temperature was set to 160°C, and the etching rate of indium tin oxide was calculated. The results are shown in Table 5. (Example 9-2) The etching rate of the indium tin oxide was calculated in the same manner as in Example 9-1, except that the halogen fluoride was iodine heptafluoride and the etching gas was a mixture of iodine heptafluoride gas at a flow rate of 50 mL / min and argon gas at a flow rate of 450 mL / min. The results are shown in Table 5.

[0100] (Comparative Example 9-1) The test piece was etched in the same manner as in Example 9-1, except that a mixed gas of fluorine gas at a flow rate of 50 mL / min and argon at a flow rate of 450 mL / min was used as the etching gas, and the etching rate of indium tin oxide was calculated. The results are shown in Table 5.

[0101] (Reference example 1-1) A test piece similar to the test piece having the nickel film used in Example 3-3 was prepared. The test piece was etched in the same manner as in Example 1-1, except that the stage temperature was set to 250°C, and the etching rate of nickel was calculated. The results are shown in Table 6.

[0102] [Table 6]

[0103] (Reference example 1-2) The test piece was etched in the same manner as in Reference Example 1-1, except that the halogen fluoride was iodine heptafluoride, and the etching gas was a mixture of iodine heptafluoride gas at a flow rate of 50 mL / min and argon at a flow rate of 450 mL / min. The etching rate of nickel was calculated. The results are shown in Table 6.

[0104] (Reference example 2-1) A test piece similar to the test piece having the cobalt film used in Examples 3-5 was prepared. The test piece was etched in the same manner as in Example 1-1, except that the stage temperature was set to 250°C, and the cobalt etching rate was calculated. The results are shown in Table 6. (Reference example 2-2) The test piece was etched in the same manner as in Reference Example 2-1, except that the halogen fluoride was iodine heptafluoride, and the etching gas was a mixture of iodine heptafluoride gas at a flow rate of 50 mL / min and argon gas at a flow rate of 450 mL / min, and the cobalt etching rate was calculated. The results are shown in Table 6.

[0105] (Reference example 3-1) A test piece similar to the test piece having the copper film used in Example 3-1 was prepared. The test piece was etched in the same manner as in Example 1-1, except that the stage temperature was set to 120°C, and the copper etching rate was calculated. The results are shown in Table 6. (Reference example 3-2) The etching rate of the copper was calculated in the same manner as in Reference Example 3-1, except that the halogen fluoride was iodine heptafluoride and the etching gas was a mixture of iodine heptafluoride gas at a flow rate of 50 mL / min and argon gas at a flow rate of 450 mL / min. The results are shown in Table 6.

[0106] (Reference example 4-1) Test pieces similar to those having a photoresist film used in Examples 3-7 were prepared. Then, the test pieces were etched in the same manner as in Example 1-1, except that the stage temperature was set to 120°C, and the etching rate of the photoresist was calculated. The results are shown in Table 6. (Reference example 4-2) The test piece was etched in the same manner as in Reference Example 4-1, except that the halogen fluoride was iodine heptafluoride, the etching gas was a mixture of iodine heptafluoride gas at a flow rate of 50 mL / min and argon at a flow rate of 450 mL / min, and the stage temperature was 100° C. The etching rate of the photoresist was calculated. The results are shown in Table 6. (Reference example 4-3) The test pieces were etched in the same manner as in Reference Example 4-1, except that the etching gas was a mixture of bromine pentafluoride gas at a flow rate of 50 mL / min, fluorine gas at a flow rate of 25 mL / min, and argon at a flow rate of 425 mL / min, and the etching rate of the photoresist was calculated. The results are shown in Table 6.

[0107] As shown in Examples 1-1 to 1-4, etching of titanium oxide was possible by using an etching gas containing bromine pentafluoride or iodine heptafluoride. Furthermore, Examples 1-5 to 1-7, which used an etching gas containing 5% by volume of a simple halogen gas, had slightly lower etching rates for titanium oxide than Examples 1-1 and 1-2. On the other hand, Comparative Example 1-1, which used a mixed gas of fluorine gas and argon as the etching gas, did not allow etching of titanium oxide to proceed. This is presumably due to the reaction between the simple halogen gas and titanium oxide, resulting in the formation of a passive film.

[0108] As shown in Examples 2-1 to 2-6, etching of titanium nitride progressed by using an etching gas containing bromine pentafluoride or iodine heptafluoride. On the other hand, in Comparative Example 2-1, in which a mixed gas of fluorine gas and argon was used as the etching gas, etching of titanium nitride did not progress.

[0109] As shown in Examples 3-1 to 3-8, when titanium nitride, which is the etching target, and copper, nickel, cobalt, or photoresist, which are non-etching targets, are simultaneously etched using an etching gas containing bromine pentafluoride or iodine heptafluoride, only the titanium nitride, which is the etching target, is selectively etched, and the non-etching targets are hardly etched. On the other hand, in Comparative Examples 3-1 to 3-4, which used a mixed gas of fluorine gas and argon as the etching gas, etching of not only the non-etching targets but also the etching targets hardly progressed.

[0110] As shown in Examples 4-1, 4-2, 5-1, 5-2, 6-1, 6-2, 7-1, 7-2, 7-3, 7-4, 8-1, 8-2, 9-1, and 9-2, by using an etching gas containing bromine pentafluoride or iodine heptafluoride, it was possible to etch titanium oxynitride, titanium oxyfluoride, titanium, tin oxide, indium oxide, and indium tin oxide. On the other hand, in Comparative Examples 4-1 to 9-1, in which a mixed gas of fluorine gas and argon was used as the etching gas, etching of any of the etching targets hardly progressed.

[0111] As shown in Reference Examples 1-1, 1-2, 2-1, 2-2, 3-1, 3-2, 4-1, and 4-2, even when an etching gas containing bromine pentafluoride or iodine heptafluoride was used, nickel, cobalt, copper, and photoresist were hardly etched. From these results, it can be seen that by performing the etching of each of the above examples, it is possible to selectively etch titanium oxide, titanium nitride, titanium oxynitride, titanium oxyfluoride, titanium, tin oxide, indium oxide, and indium tin oxide without etching nickel, cobalt, copper, and photoresist, which are non-etching targets.

[0112] On the other hand, as shown in Reference Example 4-3, when a mixed gas containing fluorine gas was used as the etching gas, etching of the photoresist progressed slightly. This suggests that the presence of a simple halogen gas in the etching gas affects the etching selectivity between the etching target and the non-etching target. [Explanation of symbols]

[0113] 1. Halogen fluoride gas supply unit 2. Inert gas supply section 3. Halogen fluoride gas flow control device 4. Inert gas flow control device 5. Halogen fluoride gas supply pipe 6. Inert gas supply piping 7, 16... Pressure gauge 8. Inert gas pressure control device 10. Chamber 11 Stages 12. Material to be etched 13 Exhaust piping 14...Thermometer 15. Vacuum pump 17. Halogen only gas supply unit 18. Halogen-only gas flow control device 19. Halogen gas supply piping 21. Silicon substrate 22 Titanium oxide film 23 Nickel substrate

Claims

1. A dry etching method comprising a dry etching step of contacting an etching gas containing a halogen fluoride, which is a compound of bromine or iodine and fluorine, with a member to be etched having an etching object that is the target of etching with the etching gas, and etching the etching object without using plasma, wherein the etching object contains at least one metal selected from titanium, indium, and tin.

2. 2. The dry etching method according to claim 1, wherein the halogen fluoride is at least one selected from the group consisting of bromine monofluoride, bromine trifluoride, bromine pentafluoride, iodine pentafluoride, and iodine heptafluoride.

3. 3. The dry etching method according to claim 1, wherein the etching gas is a mixed gas containing the halogen fluoride and an inert gas.

4. 4. The dry etching method according to claim 1, wherein the content of the halogen elemental gas contained in the etching gas is less than 5% by volume.

5. The dry etching method according to any one of claims 1 to 4, wherein the dry etching step is carried out at a temperature of 40°C or higher and 250°C or lower.

6. 5. The dry etching method according to claim 1, wherein the dry etching step is carried out at a temperature of 80° C. or higher and 150° C. or lower.

7. 7. The dry etching method according to claim 1, wherein the dry etching step is carried out under a pressure condition of 1 Pa or more and 100 kPa or less.

8. the member to be etched includes a non-etching object that is not a target for etching by the etching gas, and the etching object; the non-etching object comprises at least one selected from copper, nickel, cobalt, and photoresist; 8. The dry etching method according to claim 1, wherein the etching object is selectively etched relative to the non-etching object.

9. 9. The dry etching method according to claim 1, wherein the etching object is at least one selected from the group consisting of an elemental metal, an oxide of the metal, a nitride of the metal, an oxynitride of the metal, and an oxyfluoride of the metal.

10. A method for manufacturing a semiconductor element, comprising the steps of: manufacturing a semiconductor element by using the dry etching method according to any one of claims 1 to 9; the member to be etched is a semiconductor substrate having the etching target, A method for manufacturing a semiconductor device, comprising a processing step of removing at least a part of the etching object from the semiconductor substrate by etching.

11. A cleaning method for cleaning an inner surface of a chamber of a semiconductor device manufacturing apparatus using the dry etching method according to any one of claims 1 to 9, comprising: the member to be etched is the chamber, the chamber has deposits on its inner surface that have been deposited during operation of the semiconductor device manufacturing apparatus, and the deposits are the etching target; a cleaning method comprising a cleaning step of removing the deposits from the inner surface of the chamber by etching.

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