Dry etching method, method for manufacturing semiconductor device, and etching device

Abstract

The purpose of the present invention is to provide: a dry etching method with which it is possible to reduce deposition of etching residue; a method for manufacturing a semiconductor device; and an etching device. The present invention relates to a dry etching method for etching a germanium-containing film to be etched by means of at least one gas (first gas) which is selected from the group consisting of IF7, IF5, BrF5, BrF3, MoF6, GeF4, and ClF, and a gas (second gas) which is different from the first gas, and is composed of at least one gas that is selected from the group consisting of F2, ClF3, and BrF5.

Description

Dry etching method, semiconductor device manufacturing method and etching apparatus

[0001] The present disclosure relates to a dry etching method, a method for manufacturing a semiconductor device, and an etching apparatus.

[0002] As a technique for etching SiGe, ClF ３ Techniques using gases or the like are known (Patent Documents 1 to 3).

[0003] JP 2019-201102 A JP 2022-191045 A JP 2019-129313 A

[0004] As a result of the study by the present inventors, IF ７ , IF ５ , BrF ５ , BrF ３ , MoF ６ , GeF ４ It has been newly discovered that when a germanium-containing film is etched using ClF and ClF, etching residues containing Ge are deposited on the etched wafer. There is concern that the etching residues may adversely affect the characteristics of semiconductor devices, and further improvement has been found.

[0005] The present disclosure aims to solve the above-mentioned problems and provide a dry etching method, a semiconductor device manufacturing method, and an etching apparatus that can reduce the accumulation of etching residues.

[0006] As a result of extensive investigation, the present inventors have found that IF ７ , IF ５ , BrF ５ , BrF ３ , MoF ６ , GeF ４ Even when at least one gas (first gas) selected from the group consisting of F and ClF is used, ２ , ClF ３ and BrF ５ The present inventors have found that the deposition of etching residues can be reduced by using at least one gas (second gas) selected from the group consisting of the following, which is different from the first gas, and have completed the present disclosure.

[0007] That is, the present disclosure (1) is IF７ , IF ５ , BrF ５ , BrF ３ , MoF ６ , GeF ４ and ClF (first gas), and at least one gas selected from the group consisting of F ２ , ClF ３ and BrF ５ and a gas (second gas) different from the first gas, wherein the gas is at least one kind of gas selected from the group consisting of:

[0008] The present disclosure (2) is a method for manufacturing a semiconductor device, ７ The present disclosure relates to a dry etching method according to (1).

[0009] The present disclosure (3) is a method for manufacturing a gas mixture comprising: ２ The present disclosure relates to a dry etching method according to (1) or (2), wherein

[0010] The present disclosure (4) relates to the dry etching method according to any one of the present disclosures (1) to (3), in which the etching temperature is 0 to 300°C.

[0011] The present disclosure (5) relates to the dry etching method according to any one of the present disclosures (1) to (4), in which a gas A containing the first gas and the second gas is brought into contact with the film to be etched.

[0012] The present disclosure (6) relates to the dry etching method according to the present disclosure (5), wherein the partial pressure of the first gas in gas A is 0.1 to 10 Pa.

[0013] The present disclosure (7) relates to the dry etching method according to the present disclosure (5) or (6), in which the partial pressure of the second gas in gas A is 0.1 to 500 Pa.

[0014] The present disclosure (8) relates to the dry etching method according to any one of the present disclosures (5) to (7), wherein the ratio of the partial pressure of the first gas to the partial pressure of the second gas in gas A (partial pressure of the first gas / partial pressure of the second gas) is 0.001 to 100.

[0015] The present disclosure (9) relates to the dry etching method according to any one of the present disclosures (5) to (7), wherein the ratio of the partial pressure of the first gas to the partial pressure of the second gas in gas A (partial pressure of the first gas / partial pressure of the second gas) is 0.01 or more and less than 1.0.

[0016] The present disclosure (10) relates to the dry etching method according to any one of the present disclosures (1) to (4), which includes a first step of contacting a gas B containing the first gas with the film to be etched, and a second step of contacting a gas C containing the second gas with the film to be etched.

[0017] The present disclosure (11) relates to the dry etching method according to the present disclosure (10), wherein the partial pressure of the first gas in gas B is 0.1 to 10 Pa.

[0018] The present disclosure (12) relates to the dry etching method according to the present disclosure (10) or (11), wherein the partial pressure of the second gas in the gas C is 0.1 to 500 Pa.

[0019] The present disclosure (13) relates to the dry etching method according to any one of the present disclosures (10) to (12), wherein the ratio of the partial pressure of the first gas in gas B to the partial pressure of the second gas in gas C (partial pressure of the first gas in gas B / partial pressure of the second gas in gas C) is 0.001 to 100.

[0020] The present disclosure (14) relates to the dry etching method according to any one of the present disclosures (10) to (12), in which the ratio of the partial pressure of the first gas in gas B to the partial pressure of the second gas in gas C (partial pressure of the first gas in gas B / partial pressure of the second gas in gas C) is 0.01 or more and less than 1.0.

[0021] The present disclosure (15) is a method for manufacturing a gas turbine engine, ７ and the second gas is F ２ The dry etching method according to any one of the present disclosures (1) to (14),

[0022] The present disclosure (16) relates to a method for manufacturing a semiconductor device, including a step of applying the dry etching method according to any one of the present disclosures (1) to (15) to a germanium-containing film on a substrate, thereby etching the film.

[0023] The present disclosure (17) provides a mounting table for mounting an object to be processed, and an IF for the object to be processed. ７ , IF ５ , BrF ５ , BrF ３ , MoF ６ , GeF ４ a first gas supply unit that supplies at least one gas selected from the group consisting of F and ClF to the object to be processed; ２ , ClF ３ and BrF ５ and a second gas supply unit that supplies at least one gas selected from the group consisting of:

[0024] The dry etching method of the present disclosure is an IF ７ , IF ５ , BrF ５ , BrF ３ , MoF ６ , GeF ４ and ClF (first gas), and F ２ , ClF ３ and BrF ５ and a gas (second gas) different from the first gas, which is at least one kind of gas selected from the group consisting of:

[0025] The method for manufacturing a semiconductor device according to the present disclosure includes a step of applying the dry etching method according to the present disclosure to a germanium-containing film on a substrate to etch the film. Because the method for manufacturing a semiconductor device according to the present disclosure includes a step of applying the dry etching method according to the present disclosure to etch the germanium-containing film on a substrate, deposition of etching residues can be reduced, and high-quality semiconductor devices can be manufactured.

[0026] The etching apparatus of the present disclosure includes a stage on which a workpiece is placed, and an IF for the workpiece. ７ , IF ５ , BrF ５ , BrF３ , MoF ６ , GeF ４ and a first gas supply unit that supplies at least one gas selected from the group consisting of ClF and F to the object to be processed. ２ , ClF ３ and BrF ５ and a second gas supply unit that supplies at least one gas selected from the group consisting of the above, which is different from the first gas, thereby making it possible to reduce the accumulation of etching residues.

[0027] FIG. 1 is a schematic diagram showing an example of an etching apparatus according to the present disclosure.

[0028] The present disclosure will be described in detail below, but the following description of the constituent elements is an example of an embodiment of the present disclosure, and the present disclosure is not limited to these specific details. Various modifications can be made within the scope of the gist of the present disclosure.

[0029] In this specification, unless otherwise specified, the expression "X to Y" in the description of a numerical range means at least X and at most Y. For example, "1 to 5% by mass" means "at least 1% by mass and at most 5% by mass."

[0030] <Dry Etching Method> The dry etching method of the present disclosure is an IF ７ , IF ５ , BrF ５ , BrF ３ , MoF ６ , GeF ４ and ClF (first gas), and F ２ , ClF ３ and BrF ５ and a second gas (a gas different from the first gas) selected from the group consisting of: (a) a first gas containing germanium, (b) a second gas containing germanium, and (c) a second gas containing germanium, which is different from the first gas. This method can reduce the accumulation of etching residues.

[0031] The reason why the above-mentioned effects are obtained is not entirely clear, but it is presumed to be due to the following mechanism. ７ , IF ５ , BrF ５ , BrF３ , MoF ６ , GeF ４ and ClF, and the at least one gas (first gas) selected from the group consisting of ClF ３ The first gas has lower oxidizing properties than the first gas and also has low reactivity with germanium-containing films, which gives it an advantage in terms of controlling the etching rate. However, when a germanium-containing film is etched using the first gas, etching residues containing Ge are deposited on the wafer after etching due to the low reactivity with the germanium-containing film. In the present disclosure, by supplying a second gas having higher oxidizing properties than the first gas together with the first gas or after supplying the first gas, the etching residues containing Ge react with the second gas, thereby removing the etching residues and reducing the deposition of the etching residues.

[0032] <<Film to be etched>> The germanium-containing film to be etched is not particularly limited as long as it is a film containing germanium, and examples thereof include a germanium film, a germanium oxide film, a germanium nitride film, a germanium oxynitride film, and a film containing at least Si and Ge. Germanium may also form an alloy with another metal. These may be used alone or in combination of two or more. Among these, a film containing at least Si and Ge is preferred, and SiGe is more preferred.

[0033] The content of Ge in 100 mass % of the germanium-containing film to be etched is preferably 1 mass % or more, more preferably 5 mass % or more, and the upper limit is not particularly limited and may be 100 mass %, but is, for example, 99 mass % or less. In this specification, the content of each element in the film is measured by X-ray photoelectron spectroscopy (XPS, manufactured by ULVAC-PHI, PHI5000 VersaProbe II).

[0034] The film containing at least Si and Ge is silicon germanium (SiGe, where SiGe does not indicate the stoichiometric ratio of each element, but refers to a film containing silicon atoms and germanium atoms. For example, SiGe (Si １－ｘ Ge ｘ , x is 0.01 to 0.99, but may be 0.05 to 0.5.) membranes are also suitable.

[0035] In the dry etching method of the present disclosure, examples of the object to be processed include a silicon substrate, a compound semiconductor substrate, a quartz substrate, and a glass substrate. In addition to the above-mentioned film to be etched, a silicon film, a silicon oxide film, a silicon nitride film, a metal wiring film other than the above-mentioned metals, and the like may be formed on the surface of the object to be processed.

[0036] The method for forming the etching film on the surface of the workpiece is not particularly limited, but examples thereof include chemical vapor deposition (CVD) and sputtering. The thickness of the etching film is also not particularly limited, but may be, for example, 0.1 nm to 1 μm.

[0037] In the dry etching method of the present disclosure, IF ７ , IF ５ , BrF ５ , BrF ３ , MoF ６ , GeF ４ and ClF (first gas), and F ２ , ClF ３ and BrF ５ and a gas (second gas) different from the first gas, which is at least one gas selected from the group consisting of:

[0038] <<IF ７ , IF ５ , BrF ５ , BrF ３ , MoF ６ , GeF ４ and at least one gas (first gas) selected from the group consisting of IF and ClF ７ , IF ５ , BrF ５ , BrF ３ , MoF ６ , GeF ４ and ClF, and the at least one gas (first gas) selected from the group consisting of IF ７ , IF ５ , ClF, MoF ６ Preferably, the gas is at least one selected from the group consisting of IF ７ , IF５ and ClF, more preferably at least one gas selected from the group consisting of IF ７ The first gas may be used alone or in combination of two or more kinds.

[0039] IF ７ , IF ５ , BrF ５ , BrF ３ , MoF ６ , GeF ４ The gas containing at least one gas (first gas) selected from the group consisting of ClF and ClF is not particularly limited as long as it contains the first gas, but may also contain an inert gas or the like in addition to the first gas.

[0040] Examples of inert gases include Ar and N ２ , He, Ne, Kr, etc. These may be used alone or in combination of two or more.

[0041] The content of the first gas in 100% by volume of the gas containing the first gas can be, for example, 10 to 100% by volume. In this case, the content of the inert gas in 100% by volume of the gas containing the first gas can be, for example, 0 to 90% by volume. In this specification, the content of each gas component is measured, for example, by infrared spectroscopy.

[0042] In 100% by volume of the gas containing the first gas, the total content of the first gas and the inert gas is preferably 80% by volume or more, more preferably 90% by volume or more, even more preferably 95% by volume or more, particularly preferably 98% by volume or more, and may be 100% by volume.

[0043] <<F ２ , ClF ３ and BrF ５ At least one gas selected from the group consisting of: ２ , ClF ３ and BrF ５ At least one gas selected from the group consisting of: ２ The second gas may be used alone or in combination of two or more kinds.

[0044] In the first gas and the second gas, BrF ５ The second gas is, as described above, F ２ , ClF ３ and BrF ５ and wherein the first gas is at least one gas selected from the group consisting of BrF ５ When the second gas contains F ２ and ClF ３ On the other hand, the first gas is at least one gas selected from the group consisting of BrF ５ If the second gas does not contain F ２ , ClF ３ and BrF ５ At least one gas selected from the group consisting of:

[0045] F ２ , ClF ３ and BrF ５ The gas containing at least one gas selected from the group consisting of (a) and (b) different from the first gas is not particularly limited as long as it contains the second gas, but may contain an inert gas other than the second gas. Examples of the inert gas are as described above.

[0046] The content of the second gas in 100% by volume of the gas containing the second gas can be, for example, 10 to 100% by volume. In this case, the content of the inert gas in 100% by volume of the gas containing the second gas can be, for example, 0 to 90% by volume.

[0047] In 100% by volume of the gas containing the second gas, the total content of the second gas and the inert gas is preferably 80% by volume or more, more preferably 90% by volume or more, even more preferably 95% by volume or more, particularly preferably 98% by volume or more, and may be 100% by volume.

[0048] In the dry etching method of the present disclosure, it is preferable to bring the first gas and the second gas into contact with the film to be etched in a non-plasma environment without a plasma state, because if the object to be processed is a semiconductor device substrate, the non-plasma environment can avoid the risk of electrical damage to the substrate caused by the plasma gas.

[0049] The temperature during etching is preferably 0 to 300°C, and is more preferably 10°C or higher, particularly preferably 20°C or higher, and most preferably 25°C or higher, because this allows the film to be etched more suitably. To reduce damage to the film to be etched, the temperature is more preferably 250°C or lower, even more preferably 200°C or lower, and particularly preferably 150°C or lower. The temperature during etching refers to the temperature of the substrate (film to be etched) when processed by the dry etching method of the present disclosure, and is equal to the temperature of the stage when the substrate is placed on a stage.

[0050] The dry etching method of the present disclosure preferably excludes "an etching method comprising: a step of storing, in a processing vessel, a substrate having a recess formed by a sidewall that is a germanium-containing film; an etching step of supplying an etching gas containing a first fluorine-containing gas and a second fluorine-containing gas into the processing vessel to etch the first sidewall and the second sidewall; and a shape control step, included in the etching step, of adjusting a partial pressure of the first fluorine-containing gas in the processing vessel or a ratio of a flow rate of the second fluorine-containing gas to the first fluorine-containing gas supplied into the processing vessel to control a shape of the sidewall after etching."

[0051] [First Dry Etching Method] The following describes a first dry etching method of the present disclosure in which a gas containing the first gas and a gas containing the second gas are simultaneously brought into contact with a film to be etched. In the first dry etching method, a gas A containing the first gas and the second gas is brought into contact with the film to be etched. Gas A contains at least the first gas and the second gas.

[0052] In the first dry etching method, the etching process can be performed with the first gas while the deposition of etching residues is reduced by the second gas.

[0053] The first gas and the second gas contained in the gas A are as described above, including preferred embodiments thereof.

[0054] In gas A, the partial pressure of the first gas is preferably 0.1 to 10 Pa, more preferably 0.1 to 9.0 Pa, even more preferably 0.1 to 5.0 Pa, and particularly preferably 0.1 to 2.0 Pa. From the viewpoint of increasing the etching rate, the partial pressure of the first gas in gas A may be 0.3 Pa or more, 0.4 Pa or more, or 0.8 Pa or more. In gas A, the partial pressure of the second gas is preferably 0.1 to 500 Pa, more preferably 1.0 to 400 Pa, even more preferably 5.0 to 300 Pa, and particularly preferably 10.0 to 200 Pa. In gas A, the sum of the partial pressure of the first gas and the partial pressure of the second gas is preferably 0.2 to 510 Pa, more preferably 1.3 to 409 Pa, even more preferably 5.4 to 305 Pa, and particularly preferably 10.8 to 202 Pa. The partial pressure of the first gas is IF ７ Divided pressure of IF ５ Partial pressure of BrF ５ Partial pressure of BrF ３ partial pressure of MoF ６ partial pressure of GeF ４ The term "second gas" refers to the sum of the partial pressures of ClF and ClF. Other similar descriptions are similar. In this specification, the partial pressure of each gas component is measured using a pressure gauge. Specifically, the total pressure is measured using a pressure gauge, and the partial pressure of each gas component is calculated from the flow rate ratio of the introduced gas components. The preferred range of the partial pressure of the second gas decreases as the processing temperature increases. For example, the partial pressure of the second gas is preferably 50 Pa or more at around room temperature of 0 to 50°C in order to sufficiently remove residue, and is preferably 1.0 to 10 Pa at 100°C or higher in order to reduce damage to the film to be etched.

[0055] In gas A, the ratio of the partial pressure of the first gas to the partial pressure of the second gas (partial pressure of the first gas / partial pressure of the second gas) is preferably 0.001 to 100, more preferably 0.01 to 10, even more preferably 0.01 or more and less than 1.0, particularly preferably 0.05 to 0.8, and most preferably 0.1 to 0.6.

[0056] Gas A is not particularly limited as long as it contains the first gas and the second gas, but may contain an inert gas in addition to the first gas and the second gas. Examples of the inert gas are as described above.

[0057] The total content of the first gas and the second gas may be, for example, 10 to 100% by volume relative to 100% by volume of gas A. In this case, the content of the inert gas may be, for example, 0 to 90% by volume relative to 100% by volume of gas A.

[0058] In 100% by volume of gas A, the total content of the first gas, the second gas, and the inert gas is preferably 80% by volume or more, more preferably 90% by volume or more, even more preferably 95% by volume or more, particularly preferably 98% by volume or more, and may be 100% by volume.

[0059] In gas A, the ratio of the "sum of the partial pressures of the first gas and the second gas" to the total pressure ("sum of the partial pressures of the first gas and the second gas" / total pressure) is preferably 0.1 to 1.0, more preferably 0.2 to 1.0, even more preferably 0.5 to 1.0, particularly preferably 0.8 to 1.0, and most preferably 0.9 to 1.0. This tends to more favorably achieve the effects of the present disclosure. This is presumably because, when the ratio of the "sum of the partial pressures of the first gas and the second gas" to the total pressure in the processing vessel is small, such as when it is less than 0.1, the amounts of the first gas and the second gas present in the processing vessel are small to begin with, making it difficult for the problem of deposition of etching residues to occur, and the effects of the present disclosure may not be favorably achieved.

[0060] In the first dry etching method, the object to be etched is preferably placed in a processing vessel. In the first dry etching method, after contacting Gas A with the film to be etched, a step of reducing the pressure inside the processing vessel is preferably performed. This is because by-products generated during etching can be removed. The reduced pressure state refers to a state in which the pressure inside the processing vessel is lower than the pressure during etching, and generally refers to a pressure of 0.133 kPa or less.

[0061] The first dry etching method preferably includes a step of replacing the atmosphere in the processing vessel with an inert gas after contacting the gas A with the film to be etched. This is because by-products generated during etching can be removed. The first dry etching method may also include a step of replacing the atmosphere in the processing vessel with an inert gas after a step of reducing the pressure in the processing vessel.

[0062] [Second Dry Etching Method] Next, a second dry etching method according to the present disclosure will be described, which includes a first step of contacting the film to be etched with a gas B containing the first gas and a second step of contacting the film to be etched with a gas C containing the second gas. Gas B contains at least the first gas, and gas C contains at least the second gas.

[0063] In the second dry etching method, after the etching process using the first gas, the etching residue is removed by the second gas, and the accumulation of the etching residue can be reduced.

[0064] The first gas contained in gas B and the second gas contained in gas C are as described above, including preferred embodiments.

[0065] Gas B is not particularly limited as long as it contains the first gas, but may also contain an inert gas other than the first gas. Gas C is not particularly limited as long as it contains the second gas, but may also contain an inert gas other than the second gas. Examples of inert gases are as described above.

[0066] The content of the first gas in 100% by volume of gas B can be, for example, 10 to 100% by volume. In this case, the content of the inert gas in 100% by volume of gas B can be, for example, 0 to 90% by volume. The content of the second gas in 100% by volume of gas C can be, for example, 10 to 100% by volume. In this case, the content of the inert gas in 100% by volume of gas C can be, for example, 0 to 90% by volume.

[0067] In 100% by volume of Gas B, the total content of the first gas and the inert gas is preferably 80% by volume or more, more preferably 90% by volume or more, even more preferably 95% by volume or more, particularly preferably 98% by volume or more, and may be 100% by volume. In 100% by volume of Gas C, the total content of the second gas and the inert gas is preferably 80% by volume or more, more preferably 90% by volume or more, even more preferably 95% by volume or more, particularly preferably 98% by volume or more, and may be 100% by volume.

[0068] The partial pressure of the first gas in gas B is preferably 0.1 to 10 Pa, more preferably 0.1 to 9.0 Pa, even more preferably 0.1 to 5.0 Pa, and particularly preferably 0.1 to 2.0 Pa. From the viewpoint of increasing the etching rate, the partial pressure of the first gas in gas B may be 0.3 Pa or more, 0.4 Pa or more, or 0.8 Pa or more.

[0069] In Gas C, the partial pressure of the second gas is preferably 0.1 to 500 Pa, more preferably 1.0 to 400 Pa, even more preferably 5.0 to 300 Pa, and particularly preferably 10.0 to 200 Pa. The preferred range of the partial pressure of the second gas decreases as the processing temperature increases. For example, the partial pressure of the second gas is preferably 50 Pa or higher at around room temperature of 0 to 50°C in order to sufficiently remove residue, and is preferably 1.0 to 10 Pa at 100°C or higher in order to reduce damage to the film to be etched.

[0070] The ratio of the partial pressure of the first gas in gas B to the partial pressure of the second gas in gas C (partial pressure of the first gas in gas B / partial pressure of the second gas in gas C) is the same as in the case of gas A.

[0071] In the second dry etching method, the object to be etched is preferably placed in a processing vessel. In the second dry etching method, after contacting Gas B and Gas C with the film to be etched, the processing vessel is preferably subjected to a reduced pressure state. This is because by-products generated during etching can be removed.

[0072] The second dry etching method preferably includes a step of substituting an inert gas for the atmosphere in the processing vessel after contacting Gas B and Gas C with the film to be etched. This is because by-products generated during etching can be removed. The second dry etching method may include a step of substituting an inert gas for the atmosphere in the processing vessel after a step of reducing the pressure in the processing vessel.

[0073] In the second dry etching method of the present disclosure, the above steps may be repeated multiple times to repeatedly etch the film to be etched. Since it is possible to etch the film to a certain thickness in one etching step cycle, by specifying the number of cycles, it is possible to precisely etch a layer to a desired thickness.

[0074] (First dry etching method using an etching apparatus) The first dry etching method can be realized, for example, by using an etching apparatus shown in FIG. 1. FIG. 1 is a schematic diagram of the etching apparatus used in the examples of the present disclosure. The first dry etching method will be specifically described below using the etching apparatus of FIG. 1 as an example. The etching apparatus of the present disclosure includes a stage on which a workpiece is placed, an IF (interfacial etching) device for applying IF (interfacial etching) to the workpiece, and a ion beam. ７ , IF ５ , BrF ５ , BrF ３ , MoF ６ , GeF ４ and a first gas supply unit for supplying at least one gas (first gas) selected from the group consisting of F and ClF to the object to be processed. ２ , ClF ３ and BrF ５and a second gas supply unit that supplies a gas (second gas) that is different from the first gas and that is at least one gas selected from the group consisting of: The etching apparatus of the present disclosure may further include an inert gas supply unit that supplies an inert gas to the object to be processed.

[0075] The etching apparatus of the present disclosure preferably excludes "an etching apparatus including: a processing vessel for storing a substrate having a recessed portion formed by a sidewall that is a germanium-containing film; an etching gas supply unit for supplying an etching gas containing a first fluorine-containing gas and a second fluorine-containing gas into the processing vessel to etch the sidewall; and an adjustment unit for adjusting the partial pressure of the first fluorine-containing gas in the processing vessel during the etching or adjusting the ratio of the flow rate of the second fluorine-containing gas to the first fluorine-containing gas supplied into the processing vessel, in order to control the shape of the sidewall after the etching."

[0076] In the first dry etching method, a gas A containing a gas containing a first gas (also simply referred to as the first gas) and a gas containing a second gas (also simply referred to as the second gas) is brought into contact with a film to be etched. First, a workpiece 10 having a germanium-containing film to be etched formed thereon is placed on a mounting portion 111 in a processing vessel 110. Next, a vacuum pump 193 is used to evacuate the interior of the processing vessel 110, the pipe 121, the pipes 131 and 132, the pipes 141 and 142, the pipes 151 and 152, the liquid nitrogen trap 194, and the pipe 191 to a predetermined pressure, and then the workpiece 10 is heated by a heating means 190.

[0077] When the workpiece 10 reaches a predetermined temperature, the second gas and the first gas are supplied at predetermined flow rates from the second gas supply unit 130 and the first gas supply unit 140 to the pipe 121. The second gas supply unit 130 adjusts the supply amount using valves V1 and V2 and a flow rate adjustment unit MFC1, and supplies the second gas from pipes 131 and 132 to the pipe 121. The first gas supply unit 140 adjusts the supply amount using valves V3 and V4 and a flow rate adjustment unit MFC2, and supplies the first gas from pipes 141 and 142 to the pipe 121.

[0078] Alternatively, the inert gas may be supplied at a predetermined flow rate from the inert gas supply unit 150 to the pipe 121. The inert gas supply unit 150 adjusts the supply amount using valves V5 and V6 and a flow rate adjustment unit MFC3, and supplies the inert gas from pipes 151 and 152 to the pipe 121.

[0079] In FIG. 1, PI1 and PI2 are pressure gauges, and the flow rate adjusting means and valves are controlled based on the indicated values.

[0080] The second gas and the first gas are mixed to a predetermined composition and supplied to the processing vessel 110. While the mixed gas is being introduced into the processing vessel 110, the pressure inside the processing vessel 110 is controlled to a predetermined value. Etching is performed by bringing the gas into contact with the germanium-containing film to be etched for a predetermined time. This first dry etching method enables plasma-less etching without the use of a plasma state, and does not require excitation of the gas by plasma or the like during etching. The gas flow rate can be appropriately set based on the volume and pressure of the processing vessel, etc.

[0081] Etching accompanied by a plasma state refers to a process in which a gas or the like at, for example, about 0.01 to 1.33 kPa is introduced into a reaction chamber, high-frequency power is applied to an outer coil or an opposing electrode to generate low-temperature gas plasma in the reaction chamber, and etching is performed by the activated chemical species such as ions and radicals that are generated therein. In the dry etching method of the present disclosure, dry etching can be performed by contacting a gas without a plasma state and without generating the above-mentioned gas plasma.

[0082] After the etching is completed, the heating by the heating means 190 is stopped to lower the temperature, and the vacuum pump 193 is stopped and the atmosphere is replaced with an inert gas to release the vacuum. As described above, the dry etching method using the etching apparatus can be used to etch a film to be etched that contains germanium.

[0083] (Etching Conditions in the First Dry Etching Method) In the first dry etching method, the temperature of the film to be etched during etching is the same as the temperature during etching described above. The temperature of the surface of the object to be etched is substantially equal to the temperature of the film to be etched, but the temperature of the surface of the object to be etched or the temperature of the film to be etched may rise due to reaction heat during the etching reaction. In the present disclosure, it is preferable that at least the temperature during etching, i.e., the temperature inside the processing vessel or the temperature of the mounting portion on which the object to be etched is placed, is within the above temperature range.

[0084] The pressure inside the processing vessel during etching is not particularly limited, but is usually 0.1 Pa to 101.3 kPa. It is preferable to perform etching within the preferred partial pressure range explained in [First dry etching method].

[0085] The etching time is not particularly limited, but is preferably within 60 minutes in consideration of the efficiency of the semiconductor device manufacturing process. Here, the etching time refers to the time from when a gas is introduced into a processing vessel in which a workpiece is placed until the mixed gas in the processing vessel is exhausted by a vacuum pump or the like to complete the etching process.

[0086] (Second Dry Etching Method Using Etching Apparatus) The second dry etching method can be realized, for example, by using the etching apparatus shown in Fig. 1. The second dry etching method will be specifically described below using the etching apparatus shown in Fig. 1 as an example.

[0087] In the second dry etching method, after the gas B containing the first gas is brought into contact with the film to be etched, the gas C containing the second gas is brought into contact with the film to be etched.

[0088] First, the object 10 to be processed, on which a germanium-containing film to be etched is formed, is placed on the mounting portion 111 in the processing vessel 110. Next, the inside of the processing vessel 110, the pipe 121, the pipes 131 and 132, the pipes 141 and 142, the pipes 151 and 152, the liquid nitrogen trap 194, and the pipe 191 are evacuated to a predetermined pressure by the vacuum pump 193, and then the object 10 to be processed is heated by the heating means 190.

[0089] When the workpiece 10 reaches a predetermined temperature, first, a first gas, which is gas B, is supplied from the first gas supply unit 140 to the pipe 121 at a predetermined flow rate. Alternatively, an inert gas may be supplied from the inert gas supply unit 150 to the pipe 121 at a predetermined flow rate. While the first gas, which is gas B, is being introduced into the processing vessel 110, the pressure inside the processing vessel 110 is controlled to a predetermined value. By introducing gas B into the processing vessel 110 for a predetermined time, the first gas is brought into contact with the film to be etched. By introducing gas B into the processing vessel 110 for a predetermined time, the film to be etched containing germanium can be etched.

[0090] After evacuating the gas B containing the first gas, a second gas, which is gas C, is supplied from the second gas supply unit 130 to the pipe 121 at a predetermined flow rate. Alternatively, an inert gas may be supplied from the inert gas supply unit 150 to the pipe 121 at a predetermined flow rate. While the second gas, which is gas C, is being introduced into the processing vessel 110, the pressure inside the processing vessel 110 is controlled to a predetermined pressure. By introducing gas C into the processing vessel 110 for a predetermined time, the accumulation of etching residues can be reduced.

[0091] In the second dry etching method of the present disclosure, a cycle consisting of a first step of introducing a first gas into the processing vessel 110 and a second step of introducing a second gas into the processing vessel 110 can be repeated multiple times. In the second dry etching method of the present disclosure, the thickness of the film to be etched in one cycle can be controlled by setting the etching conditions for one cycle to predetermined conditions. Therefore, by setting the thickness of the film to be etched in one cycle to a thin thickness, the thickness to be etched can be precisely controlled. In the second dry etching method of the present disclosure, the first step is preferably performed followed by the second step. Furthermore, it is preferable to perform a step of reducing the pressure in the processing vessel or a step of replacing the atmosphere in the processing vessel with an inert gas after each cycle. After the first step, a step of reducing the pressure in the processing vessel or a step of replacing the atmosphere in the processing vessel with an inert gas may be performed.

[0092] The second dry etching method also allows for plasmaless etching, which does not involve a plasma state, and does not require excitation of gases by plasma, etc. The flow rates of the second gas and the first gas can be appropriately set based on the volume and pressure of the processing vessel, etc.

[0093] In this way, in the second dry etching method using the above-mentioned etching apparatus, the gas can be brought into contact with the film to be etched without creating a plasma state, and dry etching can be performed without generating the above-mentioned gas plasma.

[0094] After the etching process is completed, the heating by the heating means 190 is stopped to lower the temperature, and the vacuum pump 193 is stopped and the atmosphere is replaced with an inert gas to release the vacuum. In this manner, the film to be etched can be etched.

[0095] (Etching Conditions in the Second Dry Etching Method) In the second dry etching method, the temperature of the film to be etched during the first step and the temperature of the film to be etched during the second step are the same as those during the etching described above. The temperature of the surface of the workpiece is substantially equal to the temperature of the film to be etched, but the temperature of the surface of the workpiece or the film to be etched may rise due to reaction heat during the etching reaction. In the present disclosure, it is preferable that at least the temperature during etching, i.e., the temperature inside the processing vessel or the temperature of the mounting portion on which the workpiece is placed, is within the above temperature range.

[0096] Furthermore, when Gas B is brought into contact with the film to be etched and when Gas C is brought into contact with the film to be etched, the pressure inside the processing vessel in which the film to be etched is placed is not particularly limited, but is usually 0.1 Pa to 101.3 kPa. It is preferable to carry out the processing within the preferred partial pressure range explained in [Second dry etching method].

[0097] The processing times for the first step and the second step are not particularly limited, but the processing time for one cycle of the first step is preferably 60 minutes or less, and the processing time for one cycle of the second step is preferably 60 minutes or less. Here, the processing time refers to the time from when a gas is introduced into a processing vessel in which a workpiece is placed until the gas in the processing vessel is subsequently evacuated by a vacuum pump or the like to complete the processing.

[0098] [Method for Manufacturing a Semiconductor Device] The dry etching method of the present disclosure described above can be used as an etching method for forming a predetermined pattern in a germanium-containing film of a semiconductor device. A semiconductor device can be manufactured by etching a germanium-containing film on a substrate using the dry etching method of the present disclosure. The method for manufacturing a semiconductor device of the present disclosure is characterized by including a step of applying the dry etching method of the present disclosure to a germanium-containing film on a substrate to etch the film. The step of supplying a gas containing a first gas and a gas containing a second gas to the film to etch the film can be performed using the dry etching method of the present disclosure described above.

[0099] Examples of the present disclosure are listed below along with comparative examples and reference examples, but the present disclosure is not limited to the following examples. In the examples, comparative examples, and reference examples, the gases used in the first step and the second step are as shown in the tables, and each gas is not diluted with an inert gas or the like (contains no components other than those listed in the tables). For the gas used in the first step in Table 1, the content of Gas 1 in the gas is 100% by volume. For the gas used in the second step in Table 1, the content of Gas 3 in the gas is 100% by volume. For the gas used in the first step in Table 2, the total content of Gas 1 and Gas 2 in the gas is 100% by volume. For the gas used in the first step in Table 3, the content of Gas 1 in the gas is 100% by volume.

[0100] [Example 1] IF ７ Cylinders filled with F ２ The etching apparatus was constructed by connecting a cylinder filled with HCl and an Al processing vessel with a metal pipe made of SUS304. The etching process was carried out using the etching apparatus shown in FIG. 1. ０．８ Ge ０．２ (All values ​​are composition ratios)) was formed on a wafer (underlying SiO ２ The membrane was introduced into a treatment vessel, and the stage temperature was set to 25°C. ７ was passed through the gas for 100 seconds under a pressure of 0.5 Pa (IF in the gas). ７ Content: 100% by volume. Then, in the second step, ２ was passed through the gas for 100 seconds under a pressure condition of 100 Pa (F in the gas). ２ In Example 1, IF content: 100% by volume. ７ , F ２ were supplied alternately.

[0101] Examples 2 to 10, Comparative Examples 1 to 5 were carried out in the same manner as in Example 1, except that the conditions were changed as shown in Table 1. In Comparative Examples 1 to 5, only the first step was carried out, as shown in Table 1.

[0102] [Example 11] In accordance with the conditions shown in Table 2, IF was used as the first step. ７ and F ２were simultaneously supplied at a volume ratio of 1:2 and allowed to flow for 100 seconds under a total pressure condition of 3 Pa (stage temperature 150°C) (IF in the gas). ７ and F ２ The total content of the above: 100% by volume. The other steps were the same as in Example 1. In Example 11, as shown in Table 2, only the first step was carried out.

[0103] [Examples 12 to 19] In the first step, IF was ７ and F ２ are supplied at a volume ratio that results in the partial pressure shown in Table 2, and the total pressure is IF ７ and F ２ The same procedures as in Example 11 were carried out except that the pressure conditions were changed to the total value of the partial pressures of the above and the stage temperature was changed to the temperatures shown in Table 2.

[0104] Reference Examples 1 and 2 were carried out in the same manner as in Example 1, except that the conditions were changed as shown in Table 3. As shown in Table 3, in Reference Examples 1 and 2, only the first step was carried out.

[0105] (Evaluation of Etching Residues) After the process was completed, the silicon germanium wafer was removed from the chamber, and the cross section of the wafer was observed using a scanning electron microscope (SEM, SU-8000 manufactured by Hitachi). The observed area (area) was set as 100%, and the percentage of that area that was covered with residues was calculated.

[0106] (Analysis of Etching Residue) In Comparative Example 1, after the process was completed, the SiO ２ Residues were found to be deposited on the film, and these residues were analyzed. Specifically, the residues were analyzed using a scanning electron microscope energy dispersive X-ray spectrometer (SEM-EDX, SU-8000 manufactured by Hitachi) to measure the IF ７ When the surface of the wafer was observed after the treatment, Ge was detected in the residue, which revealed that Ge was contained in the etching residue.

[0107]

[0108]

[0109]

[0110] From Table 3, ClF ３ When IF was used, no residue was observed. ７ The generation of etching residue was confirmed only when IF was used. ７ , IF ５ , BrF ５ , BrF ３ , MoF ６ , GeF ４ This is a phenomenon specific to ClF and has been newly confirmed by the present inventors.

[0111] From Tables 1 and 2, IF ７ The residues observed when etching SiGe using F ２ If ７ or after etching treatment. ２ It was confirmed that the amount of residue was reduced by flowing IF7. As shown in Comparative Example 3, when the partial pressure of IF7 in the first step was high, the amount of residue generated was high, and Examples 3 and 6 resulted in more residue than Examples 1, 2, 4, and 5. In Examples 14 to 16, the partial pressure of the second gas was lower than the partial pressure of the first gas, i.e., the partial pressure of the first gas / partial pressure of the second gas exceeded 1.0, resulting in more residue than Examples 11 to 13. However, the deposition of residue was reduced compared to Comparative Examples 1, 4, and 5. Comparing Examples 12 and 17, Example 17, which had the same partial pressure of the second gas but a lower processing temperature, resulted in more residue than Example 12.

[0112] From the above, IF ７ , IF ５ , BrF ５ , BrF ３ , MoF ６ , GeF ４ and ClF (first gas), and F ２ , ClF ３ and BrF ５ It has been found that the deposition of etching residues can be reduced in the dry etching method of the example in which a film to be etched containing germanium is etched by using at least one gas selected from the group consisting of: and a gas (second gas) different from the first gas.

[0113] REFERENCE SIGNS LIST 10 Object to be processed 100 Etching apparatus 110 Processing container 111 Mounting section 121 Pipe 130 Second gas supply section 131, 132 Pipe 140 First gas supply section 141, 142 Pipe 150 Inert gas supply section 151, 152 Pipe 190 Heating means 191, 192 Pipe 193 Vacuum pump 194 Liquid nitrogen trap MFC1, MFC2, MFC3 Flow rate adjusting means PI1, PI2 Pressure gauge V1, V2, V3, V4, V5, V6, V7, V8 Valve

Claims

1. IF ７ , IF ５ , BrF ５ , BrF ３ , MoF ６ , GeF ４ and ClF (first gas), and at least one gas selected from the group consisting of F ２ , ClF ３ and BrF ５ and a gas (second gas) different from the first gas, the gas being at least one kind of gas selected from the group consisting of:

2. The first gas is IF ７ 2. The dry etching method according to claim 1, wherein 3. The second gas is F ２ 2. The dry etching method according to claim 1, wherein 4. The dry etching method according to claim 1, wherein the etching temperature is 0 to 300°C.

5. A dry etching method according to claim 1, wherein a gas A containing the first gas and the second gas is brought into contact with the film to be etched.

6. A dry etching method according to claim 5, wherein the partial pressure of said first gas in gas A is 0.1 to 10 Pa.

7. A dry etching method according to claim 5, wherein the partial pressure of said second gas in gas A is 0.1 to 500 Pa.

8. A dry etching method according to claim 5, wherein the ratio of the partial pressure of the first gas to the partial pressure of the second gas in gas A (partial pressure of the first gas / partial pressure of the second gas) is 0.001 to 100.

9. A dry etching method according to claim 5, wherein the ratio of the partial pressure of the first gas to the partial pressure of the second gas in gas A (partial pressure of the first gas / partial pressure of the second gas) is 0.01 or more and less than 1.

0.

10. A dry etching method according to claim 1, comprising a first step of contacting a gas B containing the first gas with the film to be etched, and a second step of contacting a gas C containing the second gas with the film to be etched.

11. A dry etching method according to claim 10, wherein the partial pressure of said first gas in gas B is 0.1 to 10 Pa.

12. A dry etching method according to claim 10, wherein the partial pressure of said second gas in gas C is 0.1 to 500 Pa.

13. The dry etching method according to claim 10, wherein the ratio of the partial pressure of the first gas in gas B to the partial pressure of the second gas in gas C (partial pressure of the first gas in gas B / partial pressure of the second gas in gas C) is 0.001 to 100.

14. A dry etching method according to claim 10, wherein the ratio of the partial pressure of the first gas in gas B to the partial pressure of the second gas in gas C (partial pressure of the first gas in gas B / partial pressure of the second gas in gas C) is 0.01 or more and less than 1.

0.

15. The first gas is IF ７ and the second gas is F ２ 2. The dry etching method according to claim 1, wherein 16. A method for manufacturing a semiconductor device, comprising the step of applying the dry etching method according to any one of claims 1 to 15 to a germanium-containing film on a substrate, thereby etching the film.

17. A mounting table for mounting an object to be processed; and an IF for the object to be processed. ７ , IF ５ , BrF ５ , BrF ３ , MoF ６ , GeF ４ a first gas supply unit that supplies at least one gas selected from the group consisting of F and ClF to the object to be processed; ２ , ClF ３ and BrF ５ and a second gas supply unit that supplies at least one gas selected from the group consisting of:

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