Substrate processing method, method for manufacturing semiconductor device, substrate processing apparatus, and program

Abstract

Provided is a technology capable of forming a film having desired characteristics (for example, sufficient thinness, high dielectric constant, high insulation property, and so on).　The present invention includes: a first mixed film forming step for forming by performing (a) a step for preparing a substrate having a surface on which a first crystal film containing a crystallized first substance is formed and (b) a step for forming a first amorphous film, which contains an amorphous second substance, on the first crystal film, a first mixed film that has a first thickness and contains the crystallized first material and the amorphous second material, on the substrate; and (c) a step for setting, before the first mixed film forming step, a processing amount related to the first thickness in the first mixed film forming step such that the crystallization temperature of the amorphous film of the first substance that has the first thickness is higher than the crystallization temperature of the amorphous bulk of the first substance.

Description

Substrate processing method, semiconductor device manufacturing method, substrate processing apparatus, and program

[0001] The present disclosure relates to a substrate processing method, a semiconductor device manufacturing method, a substrate processing apparatus, and a program.

[0002] As part of a substrate processing process (a process for manufacturing a semiconductor device), a thin film may be formed on a substrate (see, for example, Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2021-158142

[0004] The present disclosure provides techniques that allow for the formation of films with desirable properties (eg, sufficiently thin, high dielectric constant, and high insulating properties).

[0005] According to one aspect of the present disclosure, there is provided a technology comprising: (a) a step of preparing a substrate having a first crystalline film formed on its surface, the first crystalline film including a crystallized first material; (b) a step of forming a first amorphous film including an amorphous second material on the first crystalline film; and (c) a step of setting a processing amount in the first mixed film formation step, which is related to the first thickness, before the first mixed film formation step, so that the crystallization temperature of the amorphous film of the first material of the first thickness is higher than the amorphous crystallization temperature of the bulk first material.

[0006] According to the present disclosure, it is possible to form a film having desired properties (e.g., sufficient thinness, high dielectric constant, high insulating properties, etc.).

[0007] FIG. 1 is a longitudinal cross-sectional view showing an outline of a substrate processing apparatus according to an embodiment of the present disclosure. FIG. 2 is a schematic configuration diagram of a controller of the substrate processing apparatus according to an embodiment of the present disclosure, and is a block diagram showing a control system of the controller. FIG. 3 is a diagram showing a flow of a substrate processing step according to the first embodiment. FIG. 4(A) is a diagram showing a flow of step A1-1 according to an embodiment of the present disclosure. FIG. 4(B) is a diagram showing a flow of step A2 according to an embodiment of the present disclosure. FIG. 4(C) is a diagram showing a flow of step B1 according to an embodiment of the present disclosure. FIG. 4(D) is a diagram showing a flow of step B2 according to an embodiment of the present disclosure. FIG. 5 is a diagram schematically showing the appearance of the surface of a wafer 200 at each step according to an embodiment of the present disclosure.

[0008] First Embodiment The first embodiment will be described below mainly with reference to Figures 1 to 3, 4(A) to 4(D), and 5. Note that the drawings used in the following description are all schematic, and the dimensional relationships between elements, the ratios of elements, etc. shown in the drawings do not necessarily match those in reality. Furthermore, the dimensional relationships between elements, the ratios of elements, etc. do not necessarily match between multiple drawings.

[0009] (1) Configuration of the Substrate Processing Apparatus As shown in Fig. 1, a processing furnace 202 serving as a substrate processing apparatus has a heater 207 serving as a heating mechanism (temperature adjustment unit). A reaction tube 203 is provided inside the heater 207. Inside the reaction tube 203, a processing chamber 201 is formed that can accommodate wafers 200 serving as substrates and in which processing of the wafers 200 is performed. Nozzles 249a to 249c are provided inside the processing chamber 201.

[0010] The nozzles 249a to 249c are disposed in the space between the inner wall of the reaction tube 203 and the wafer 200. A plurality of gas supply holes 250a to 250c are respectively provided on the side surfaces of the nozzles 249a to 249c, from the bottom to the top of the reaction tube 203. Gases in the nozzles 249a to 249c are supplied into the processing chamber 201 and to the wafer 200 via the gas supply holes 250a to 250c, respectively.

[0011] The gas supply pipes 232i to 232k connect the nozzles 249a to 249c to inert gas supply sources 233i to 233k, respectively. The gas supply pipes 232i to 232k are respectively provided with mass flow controllers (MFCs) 241i to 241k, which are flow rate controllers (flow rate control units), and valves 243i to 243k, which are on-off valves, in order from the upstream side of the gas flow. An inert gas supply system that supplies inert gas mainly consists of the gas supply pipes 232d to 232f, the MFCs 241d to 241f, and the valves 243d to 243f. The inert gas acts as a purge gas, carrier gas, dilution gas, etc. For example, one or more of rare gases such as argon (Ar), helium (He), neon (Ne), and xenon (Xe), and nitrogen (N2) gas can be used as the inert gas.

[0012] The gas supply pipe 232a connects the downstream side of the valve 243i of the gas supply pipe 232i to a supply source 233a that supplies a first precursor gas. The gas supply pipe 232b connects the downstream side of the valve 243i of the gas supply pipe 232i to a supply source 233b that supplies a second precursor gas. The gas supply pipe 232c connects the downstream side of the valve 243j of the gas supply pipe 232j to a supply source 233c that supplies a first reactive gas. The gas supply pipe 232d connects the downstream side of the valve 243j of the gas supply pipe 232j to a supply source 233d that supplies a second reactive gas. The gas supply pipes 232a to 232d are respectively provided with MFCs 241a to 241d and valves 243a to 243d in this order from the upstream side of the gas flow.

[0013] A first source gas supply system mainly includes the gas supply pipe 232a, the MFC 241a, and the valve 243a, which supplies a first source gas to the wafers 200. A second source gas supply system mainly includes the gas supply pipe 232b, the MFC 241b, and the valve 243b, which supplies a second source gas to the wafers 200. A first reactant gas supply system mainly includes the gas supply pipe 232c, the MFC 241c, and the valve 243c, which supplies a first reactant gas to the wafers 200. A second reactant gas supply system mainly includes the gas supply pipe 232d, the MFC 241d, and the valve 243d, which supplies a second reactant gas to the wafers 200. Note that the supply sources 233a to 233d may be included in the first source gas supply system, the second source gas supply system, the first reactant gas supply system, and the second reactant gas supply system, respectively. Furthermore, when the same type of gas as the first source gas is used as the second source gas, the first source gas supply system may be regarded as a second source gas supply system. In this case, the second source gas supply system may be omitted from the processing furnace 202. Furthermore, when the same type of gas as the first reactant gas is used as the second reactant gas, the first reactant gas supply system may be regarded as a second reactant gas supply system. In this case, the second reactant gas supply system may be omitted from the processing furnace 202.

[0014] The first source gas and the first reactive gas may be collectively regarded as a first film formation gas. In this case, the first source gas supply system and the first reactive gas supply system may be collectively regarded as a first film formation gas supply system. Also, the second source gas and the second reactive gas may be collectively regarded as a second film formation gas. In this case, the second source gas supply system and the second reactive gas supply system may be collectively regarded as a second film formation gas supply system. Also, an inert gas supply system may be included in each of the first film formation gas supply system and the second film formation gas supply system. Here, at least one of the first film formation gas supply system and the second film formation gas supply system is an example of a film formation mechanism that forms a film on wafer 200.

[0015] For example, gases containing a predetermined element can be used as the first source gas and the second source gas. In this case, films containing at least the predetermined element can be formed as the second amorphous film 402 and the first amorphous film 401 described below. For example, a metal element can be used as the predetermined element. For example, one or more of tungsten (W), titanium (Ti), molybdenum (Mo), tantalum (Ta), cobalt (Co), yttrium (Y), ruthenium (Ru), hafnium (Hf), zirconium (Zr), aluminum (Al), gallium (Ga), and indium (In) can be used as the metal element. For example, boron (B), phosphorus (P), carbon (C), and silicon (Si) can also be used as the predetermined element.

[0016] For example, tungsten hexachloride (WCl ６ ), hexafluorotungsten (WF ６ ), titanium tetrachloride (TiCl ４ ), titanium tetrafluoride (TiF ４ ), molybdenum pentachloride (MoCl ５ ), molybdenum pentafluoride (MoF ５ ), molybdenum dioxide dichloride (MoO ２ Cl ２ ), molybdenum oxide tetrachloride (MoOCl ４ ), tantalum pentachloride (TaCl ５ ), tantalum pentafluoride (TaF ５ ), cobalt difluoride (CoF ２ ), cobalt dichloride (CoCl ２ ), yttrium trifluoride (YF ３ ), yttrium trichloride (YCl ３ ), ruthenium trichloride (RuCl ３ ), ruthenium trifluoride (RuF ３ ), hafnium tetrachloride (HfCl ４ ), hafnium tetrafluoride (HfF ４ ), zirconium tetrachloride (ZrCl ４ ), zirconium tetrafluoride (ZrF ４), aluminum trichloride (AlCl ３ ), aluminum trifluoride (AlF ３ ), etc. The first gas may be, for example, boron trifluoride (BF ３ ), boron trichloride (BCl ３ ), gallium trifluoride (GaF ３ ), gallium trichloride (GaCl ３ ), indium trifluoride (InF ３ ), indium trichloride (InCl ３ ), phosphorus trifluoride (PF3), phosphorus pentafluoride (PF ５ ), phosphorus trichloride (PCl ３ ), phosphorus pentachloride (PCl ５ ), carbon tetrafluoride (CF ４ ), carbon tetrachloride (CCl ４ ), trifluoromethane (CHF ３ ), fluoromethane (CH ３ F), trichloromethane (CHCl ３ ), chloromethane (CH ３ Cl) can be used as the gas containing the predetermined element.

[0017] Also, for example, hexadimethylaminoditungsten (W ２ [N(CH ３ ) ２ ] ６ ), bis(tertiarybutylimide)bis(dimethylamido)tungsten ((t-C ４ H ９ NH) ２ W = (Nt-C ４ H ９ ) ２ ), tetrakisethylmethylaminotitanium (Ti[N(C ２ H ５ ) (CH ３ )] ４ ), bisethylcyclopentadienyl ruthenium (Ru(CH ２ CH ３ ) Cp) ２ ), biscyclopentadienyl ruthenium (Ru(Cp) ２ ), tetrakisethylmethylaminohafnium (Hf[N(CH３ ) (CH ２ CH ３ )] ４ ), tetrakisdiethylaminohafnium (Hf[N(CH ２ CH ３ ) ２ ] ４ ), tetrakisdimethylaminohafnium (Hf[N(CH ３ ) ２ ] ４ ), tris(dimethylamino)cyclopentadienyl hafnium ((Cp)Hf[N(CH ３ ) ２ ] ３ ), tetrakisethylmethylaminozirconium (Zr[N(CH ３ ) (C ２ H ５ )] ４ ), tetrakis(diethylamino)zirconium (Zr[N(CH ２ CH ３ ) ２ ] ４ ), tetrakisdimethylaminozirconium (Zr[N(CH ３ ) ２ ] ４ ), tris(dimethylamino)cyclopentadienyl zirconium ((Cp)Zr[N(CH ３ ) ２ ] ３ ), trimethylaluminum (Al(CH ３ ) ３ ), boron (BH ３ ), trimethylgallium (Ga(CH ３ ) ３ ), trimethylindium (In(CH ３ ) ３ ), phosphine (PH ３ ), methane (CH ４ ) can be used as the gas containing the predetermined element.

[0018] For example, one or more of a reducing gas, an oxidizing gas, a nitriding gas, a sulfiding gas, a selenide gas, and a telluride gas can be used as the first and second reactive gases. When one of a reducing gas, an oxidizing gas, a nitriding gas, a sulfiding gas, a selenide gas, and a telluride gas is used as the first and second reactive gases, a film mainly composed of a single element of a predetermined element, an oxide film of a predetermined element, a nitride film of a predetermined element, a sulfide film of a predetermined element, a selenide film of a predetermined element, and a telluride film of a predetermined element can be formed as the second amorphous film 402 and the first amorphous film 401, respectively, as described below.

[0019] For example, hydrogen (H ２ ) gas, deuterium (D ２ ) gas, borane (BH ３ ) gas, diborane (B ２ H ６ ) gas, carbon monoxide (CO) gas, ammonia (NH ３ ) gas, monosilane (SiH ４ ) gas, disilane (Si ２ H ６ ) gas, trisilane (Si ３ H ８ ) gas, monogermane (GeH ４ ) gas, digermane (Ge ２ H ６ ) and the like can be used as the reducing gas. For example, oxygen (O ２ ), ozone (O ３ ), water vapor (H ２ O), H ２ and O ２ mixed gas, hydrogen peroxide (H ２ O ２ ), nitrous oxide (N ２ One or more gases containing ammonia (NH ) can be used as the oxidizing gas. ３ ) gas, diazene (N ２ H ２ ) gas, hydrazine (N ２ H ４ ) gas, N ３ H ８ One or more of the hydrogen nitride gases such as sulfane (H２ S), disulfane (H ２ S ２ ), diammonium sulfide ((NH ４ ) ２ S), dimethyl sulfide ((CH ３ ) ２ One or more of the sulfur gases can be used. For example, cerane (H ２ Se), diserane (H ２ Se ２ ), dimethylselenium ((CH ３ ) ２ One or more of the following gases can be used as the selenide gas: tetraethene (H ), ... ２ Te), diterane (H ２ Te ２ ), dimethyl tellurium ((CH ３ ) ２ One or more of the telluride gases may be used, such as tellurium dioxide (Te), ...

[0020] The gas supply pipe 232e connects the downstream side of the valve 243k of the gas supply pipe 232k to a first modifying gas supply source 233e. The gas supply pipe 232f connects the downstream side of the valve 243k of the gas supply pipe 232k to a second modifying gas supply source 233f. The gas supply pipe 232g connects the downstream side of the valve 243k of the gas supply pipe 232k to a first removal gas supply source 232g. The gas supply pipe 232h connects the downstream side of the valve 243k of the gas supply pipe 232k to a second removal gas supply source 232k. The gas supply pipes 232a to 232h are respectively provided with MFCs 241a to 241k and valves 243a to 243k in this order from the upstream side of the gas flow.

[0021] A first modifying gas supply system mainly includes the gas supply pipe 232e, the MFC 241e, and the valve 243e, which supplies a first modifying gas to the wafers 200. A second modifying gas supply system mainly includes the gas supply pipe 232f, the MFC 241f, and the valve 243f, which supplies a second modifying gas to the wafers 200. A first removal gas supply system mainly includes the gas supply pipe 232g, the MFC 241g, and the valve 243g, which supplies a first removal gas to the wafers 200. A second removal gas supply system mainly includes the gas supply pipe 232h, the MFC 241h, and the valve 243h, which supplies a second removal gas to the wafers 200. The supply sources 233e to 233h may be included in the first modifying gas supply system, the second modifying gas supply system, the first removal gas supply system, and the second removal gas supply system, respectively. Furthermore, when the same type of gas as the first modifying gas is used as the second modifying gas, the first modifying gas supply system may be considered as the second modifying gas supply system. In this case, the second modifying gas supply system may be omitted from the processing furnace 202. Furthermore, when the same type of gas as the first removal gas is used as the second removal gas, the first removal gas supply system may be considered as the second removal gas supply system. In this case, the second removal gas supply system may be omitted from the processing furnace 202.

[0022] The first modifying gas and the first removal gas may be collectively referred to as a first etching gas. In this case, the first modifying gas supply system and the first removal gas supply system may be collectively referred to as a first etching gas supply system. Furthermore, the second modifying gas and the second removal gas may be collectively referred to as a second etching gas. In this case, the second modifying gas supply system and the second removal gas supply system may be collectively referred to as a second etching gas supply system. Here, at least one of the first etching gas supply system and the second etching gas supply system is an example of an etching mechanism in the present disclosure.

[0023] As the first modifying gas and the second modifying gas, for example, an F-containing gas containing fluorine (F) can be used. ２ ), nitrogen trifluoride (NF ３ ), hydrogen fluoride (HF), carbon tetrafluoride (CF ４ ), tungsten hexafluoride (WF ６), chlorine trifluoride (ClF ３ ), sulfur tetrafluoride (SF ４ ), xenon difluoride (XeF ２ At least one of these may be used as the first modifying gas.

[0024] As the removal gas, for example, a Cl-containing gas containing chlorine (Cl) can be used. As the Cl-containing gas, for example, boron trichloride (BCl ３ ), carbon tetrachloride (CCl ４ ), thionyl chloride (SOCl ２ ), sulfuryl chloride (SO ２ Cl ２ ), phosgene (COCl ２ ), phosphorus trichloride (PCl ３ ), phosphorus pentachloride (PCl ５ ), titanium tetrachloride (TiCl ４ ), silicon tetrachloride (SiCl ４ ), chlorodimethylaluminum (C ２ H ６ AlCl), etc. can be used.

[0025] The first and second modifying gases may be gases other than F-containing gases. For example, the first and second modifying gases may be Cl-containing gases, oxidizing gases, or organic ligand-containing gases. For example, the oxidizing gas may be oxygen (O ２ ), ozone (O ３ ), water vapor (H ２ O), hydrogen (H ２ ) and O ２ The organic ligand-containing gas may be a mixture of trimethylaluminum gas, acetylacetone (Hacac) gas, dimethylacetamide gas, tin (II) acetylacetonate (Sn(acac) ２) gas or hexafluoroacetylacetone (Hhfac) gas can be used. The removal gas may also be a gas other than a Cl-containing gas. For example, the removal gas may be the above-mentioned F-containing gas, oxidizing gas, or organic ligand-containing gas. As the first modifying gas, second modifying gas, first removal gas, and second removal gas, gases selected from the above gases can be used appropriately depending on the material to be etched (first material or second material). In steps A2 and B2 described below, elements contained in the first modifying gas, second modifying gas, first removal gas, and second removal gas may remain on the wafer 200. In other words, by performing steps A2 and B2, elements contained in the first modifying gas, second modifying gas, first removal gas, and second removal gas can be added (doped) to the film formed on the wafer 200. For example, when an F-containing gas is used as the first modifying gas, F can be added to the film formed on the wafer 200. In this case, the first crystalline film 301 has a larger surface area than a flat film, making it easier to retain a larger amount of F. Therefore, the first mixture film 501 to which F is added can be formed efficiently.

[0026] An exhaust pipe 231 is connected to the lower sidewall of the reaction tube 203. To the exhaust pipe 231, a pressure sensor 245 serving as a pressure detector (pressure detection unit) for detecting the pressure inside the process chamber 201, an APC (Auto Pressure Controller) valve 244 serving as a pressure regulator (pressure adjustment unit), and a vacuum pump 246 serving as a vacuum exhaust device are connected, in this order from the upstream side of the gas flow. The APC valve 244 can evacuate and stop the vacuum exhaust inside the process chamber 201 by opening and closing the valve while the vacuum pump 246 is operating. Furthermore, the APC valve 244 is configured to adjust the pressure inside the process chamber 201 by adjusting the valve opening based on pressure information detected by the pressure sensor 245 while the vacuum pump 246 is operating. An exhaust system is mainly composed of the exhaust pipe 231, the pressure sensor 245, and the APC valve 244. The vacuum pump 246 may be included in the exhaust system.

[0027] A seal cap 219 capable of closing the opening of the reaction tube 203 is provided below the reaction tube 203. A rotation mechanism 267 is provided below the seal cap 219 and connected to the boat 217 through the seal cap 219. The rotation mechanism 267 is configured to rotate the boat 217 and the wafers 200 supported by the boat 217. The seal cap 219 is configured to be raised and lowered vertically by a boat elevator 115 serving as an elevating mechanism. The boat elevator 115 is configured as a transfer device (transfer mechanism) that raises and lowers the seal cap 219 to load and unload (transfer) the wafers 200 into and out of the processing chamber 201.

[0028] A temperature sensor 263 serving as a temperature detector is installed within the reaction tube 203. The output of the heater 207 is adjusted based on temperature information detected by the temperature sensor 263, thereby enabling the temperature within the process chamber 201 to achieve a desired temperature distribution. A boat 217 serving as a substrate support is configured to support multiple wafers 200, for example, 25 to 200 wafers, in a horizontal position in multiple stages. Heat insulating plates 218 are supported in a horizontal position in multiple stages below the boat 217. Note that in this disclosure, a numerical range such as "25 to 200 wafers" means that the lower and upper limits are included in the range. Therefore, "25 to 200 wafers" means "25 to 200 wafers." The same applies to other numerical ranges.

[0029] As shown in FIG. 2 , the controller 121, which serves as a control unit, is configured as a computer including a CPU (Central Processing Unit) 121a, a RAM (Random Access Memory) 121b, a storage device 121c, and an I / O port 121d. The RAM 121b, the storage device 121c, and the I / O port 121d are configured to exchange data with the CPU 121a via an internal bus 121e. An input / output device 122, such as a touch panel, is connected to the controller 121. An external storage device 123 can also be connected to the controller 121. The substrate processing apparatus may include one or more control units. That is, control for performing the substrate processing steps described below may be performed using one control unit or multiple control units. When the term "control unit" is used in this specification, it may include not only one control unit but also multiple control units.

[0030] The storage device 121c is composed of, for example, a flash memory, an HDD (Hard Disk Drive), etc. Control programs for controlling the operation of the substrate processing apparatus, process recipes describing processing procedures and conditions, etc., described below, are readably stored in the storage device 121c. The process recipe is a combination of procedures in the substrate processing steps described below that are executed by the controller 121 to obtain a predetermined result, and functions as a program (or program product). Hereinafter, the process recipes, control programs, etc. are collectively referred to simply as programs (or program products). The process recipes are also simply referred to as recipes. In this specification, the term "program" may refer to a recipe alone, a control program alone, or both. The RAM 121b is configured as a memory area (work area) in which programs, data, etc., read by the CPU 121a are temporarily stored.

[0031] The I / O port 121d is connected to the above-mentioned MFCs 241a to 241k, valves 243a to 243k, supply sources 233a to 233k, pressure sensor 245, APC valve 244, vacuum pump 246, temperature sensor 263, heater 207, rotation mechanism 267, boat elevator 115, etc.

[0032] The CPU 121a is configured to read and execute a control program from the storage device 121c, and to read a recipe from the storage device 121c in response to input of an operation command from the input / output device 122. The CPU 121a is configured to be able to control, in accordance with the contents of the read recipe, the flow rate adjustment operation of various gases by the MFCs 241a to 241k, the opening and closing operation of the valves 243a to 243k, the opening and closing operation of the APC valve 244 and the pressure adjustment operation by the APC valve 244 based on the pressure sensor 245, the start and stop of the vacuum pump 246, the temperature adjustment operation of the heater 207 based on the temperature sensor 263, the rotation and rotation speed adjustment operation of the boat 217 by the rotation mechanism 267, the lifting and lowering operation of the boat 217 by the boat elevator 115, and the like.

[0033] The controller 121 can be configured by installing the above-mentioned program stored in the external storage device 123 into a computer. The external storage device 123 includes, for example, a magnetic disk such as an HDD, an optical disk such as a CD, a magneto-optical disk such as an MO, and a semiconductor memory such as a USB memory. The storage device 121c and the external storage device 123 are configured as computer-readable recording media on which the program is recorded. Hereinafter, these will be collectively referred to as recording media. When the term recording media is used in this specification, it may include only the storage device 121c alone, only the external storage device 123 alone, or both. Note that the program may be provided to the computer using a communication means such as the Internet or a dedicated line, without using the external storage device 123.

[0034] (2) Substrate Processing Step As an example of the first embodiment, a step of forming a first mixture film 501 containing a crystallized first substance and an amorphous second substance and having a first thickness Tm1 on a wafer 200 using the above-described processing furnace 202 will be described as one step in the manufacturing process of a semiconductor device. A flow chart of the first embodiment is shown in FIG. 3. In the following description, the operation of each component of the processing furnace 202 is configured to be controllable by the controller 121.

[0035] The term "wafer" used in this specification may refer to the wafer itself or to a laminate of the wafer and a predetermined layer or film formed on its surface. The term "surface of a wafer" used in this specification may refer to the surface of the wafer itself or to the surface of a predetermined layer or the like formed on the wafer. When described in this specification, "forming a predetermined layer on a wafer" may mean forming a predetermined layer directly on the surface of the wafer itself or forming a predetermined layer on a layer or the like formed on the wafer. When used in this specification, the term "substrate" is synonymous with the term "wafer".

[0036] Here, we will explain the background of thin crystalline films and their formation methods. To improve the performance of various semiconductor devices, there is a need to form films that are sufficiently thin, have a high dielectric constant, and have high insulating properties, for example, as high-dielectric-constant films, blocking films, and charge-trapping films. For these applications, polycrystalline films (hereinafter referred to as crystalline films) with a higher dielectric constant than amorphous films are sometimes employed. Crystalline films are formed, for example, by crystallizing amorphous films. When the thickness of an amorphous film decreases beyond a certain level, the temperature required to crystallize the amorphous film at a sufficient rate (hereinafter referred to as the crystallization temperature) becomes higher than that of bulk amorphous material. In this disclosure, the term "bulk object" refers to an object having a portion inside where the influence of the interface with other objects and the surrounding area of ​​that interface is substantially negligible. As semiconductor devices become increasingly miniaturized, there is a need to form films with a thickness that causes the aforementioned increase in the amorphous crystallization temperature. However, due to concerns about the effects of thermal stress on the quality of other films formed on the wafer and pattern collapse, an upper limit is often set for the temperature at which an amorphous film is crystallized. Therefore, it can be difficult to form an amorphous film of approximately the same thickness as the final desired film and then crystallize it to form a crystallized film of the desired thickness. Furthermore, in thin crystalline films, it is difficult for multiple crystalline grains to exist in the thickness direction, making leakage current more likely to flow through the grain boundaries. In other words, thin crystalline films can have poor insulation properties.

[0037] (Step C) In Step C, the processing amount in the first mixed film formation process (described later) related to the first thickness Tm is set so that the crystallization temperature of the amorphous film of the first material having the first thickness Tm is higher than the crystallization temperature of the amorphous bulk first material. For example, a hafnium oxide film having a thickness greater than 3 nm exhibits a similar crystallization temperature to that of bulk hafnium oxide. However, the crystallization temperature of an amorphous hafnium oxide film having a thickness of 3 nm or less is higher than that of the amorphous bulk hafnium oxide. Furthermore, the crystallization temperature of the amorphous hafnium oxide film having a thickness of 2 nm or less is even higher, making crystallization difficult. Below, we will explain an example in which hafnium oxide is used as the first material and the second material, and the first thickness Tm is set to 1 nm, and the predetermined amount is set. Step C is performed, for example, by storing a predetermined processing amount or a predetermined recipe including a processing procedure for obtaining the predetermined processing amount in the storage device 121c. After explaining Step B, we will explain Step C in detail.

[0038] (Wafer Loading) A plurality of wafers 200 are loaded (wafer charging) into the boat 217. Thereafter, the boat 217 supporting the plurality of wafers 200 is lifted by the boat elevator 115 and loaded into the processing chamber 201 (boat loading).

[0039] (Pressure Adjustment / Temperature Adjustment) The inside of the processing chamber 201, i.e., the space in which the wafers 200 are present, is evacuated (reduced pressure exhausted) by the vacuum pump 246 so as to reach a desired processing pressure (vacuum level). The wafers 200 in the processing chamber 201 are heated by the heater 207 so as to reach a desired processing temperature. The rotation mechanism 267 also starts to rotate the wafers 200. The operation of the vacuum pump 246 and the heating and rotation of the wafers 200 continue at least until the processing of the wafers 200 is completed.

[0040] In this specification, the processing temperature refers to the temperature of the wafer 200 or the temperature inside the processing chamber 201, and the processing pressure refers to the pressure inside the processing chamber 201. Furthermore, the processing time refers to the time the processing continues. Furthermore, the supply time of a certain gas refers to the time the gas is supplied to the wafer 200 or the processing chamber 201. These terms also apply to the following explanations.

[0041] (First Mixture Film Forming Process) In the first mixture film forming process, Step A and Step B are performed to form a first mixture film 501 having a first thickness Tm1 on the wafer 200, as shown in Step B2 of FIG. 5. The details of the first mixture film forming process will be described below with reference to FIG. 5. FIG. 5 is a diagram schematically illustrating the state of the surface of the wafer 200 in each process. Step D in FIG. 5 will be described in the second embodiment.

[0042] (Step A) In step A, as shown in Step A2 of FIG. 5, a wafer 200 is prepared having a first crystalline film 301 having a thickness Tc1 formed on its surface, the first crystalline film 301 containing a crystallized first substance. Here, the thickness Tc1 is preferably equal to or less than the first thickness Tm1. Note that the first crystalline film 301 may be a film substantially composed of the crystallized first substance, or the first crystalline film 301 may contain a trace amount of amorphous matter. Below, an example in which step A1 (Step A1) and step A2 (Step A2) are performed will be described.

[0043] (Step A1) In step A1, a wafer 200 is prepared, having a second crystalline film 302 having a thickness Tc2 formed on its surface, the second crystalline film 302 containing a crystallized first substance, as shown in Step A1-2 of FIG. 5. Here, the thickness Tc2 is preferably greater than the thickness Tc1 and the first thickness Tm1. The second crystalline film 302 may be a film substantially composed of the crystallized first substance, or the second crystalline film 302 may contain a trace amount of amorphous matter. Below, an example will be described in which step A1-1 (Step A-1) and step A1-2 (Step A-2) are performed as step A1.

[0044] (Step A1-1) In step A1-1, as shown in Step A1-1 of FIG. 5, a wafer 200 is prepared, on the surface of which a second amorphous film 402 containing an amorphous first substance and having a thickness Ta2 is formed. Here, the thickness Ta2 is preferably greater than the first thickness Tm1. As shown in FIG. 4(A), step A1-1 is performed by repeating a cycle including steps A1-1-1 (Step A-1-1), A1-1-2 (Step A-1-2), A1-1-3 (Step A-1-3), and A1-1-4 (Step A-1-4) a predetermined number of times (n １ times, n １ is an integer of 1 or more) to form a second amorphous film on the surface of the wafer 200.

[0045] (Step A1-1-1: Supply of first source gas) The valve 243a is opened, and a Hf-containing gas as a first source gas is flowed into the gas supply pipe 232a. The flow rate of the first source gas is adjusted by the MFC 241a, and the first source gas is supplied to the wafer 200 via the nozzle 249a. After the first source gas is supplied for a predetermined supply time, the valve 243a is closed, and the supply of the first source gas is terminated.

[0046] Examples of processing conditions for supplying the first source gas in this step include: processing temperature: 200 to 450°C, preferably 250 to 350°C; processing pressure: 10 to 120 Pa, preferably 20 to 50 Pa; and supply time: 0.1 to 120 seconds, preferably 20 to 60 seconds. In the following description, the processing temperatures in steps A1-1-1 to A1-1-4 are substantially the same. In this specification, the processing temperature refers to the temperature of the wafer 200 or the temperature inside the processing chamber 201. In this specification, the processing pressure refers to the pressure inside the processing chamber 201. In this specification, the supply time refers to the time during which a certain gas is continuously supplied. These terms also apply to the following description.

[0047] (Step A1-1-2: Exhaust) At least one of exhaust and purge is performed inside the processing chamber 201. Specifically, the APC valve 244 of the exhaust pipe 231 is opened, and the processing chamber 201 is exhausted by the vacuum pump 246. At this time, the valves 243i to 243k may be opened to supply an inert gas into the processing chamber 201, that is, to purge the processing chamber 201.

[0048] (Step A1-1-3: Supply of first reactive gas) Valve 243c is opened, and an oxidizing gas as a first reactive gas is flowed into gas supply pipe 232c. The flow rate of the first reactive gas is adjusted by MFC 241c, and the first reactive gas is supplied to wafer 200 via nozzle 249b. After supplying the first reactive gas for a predetermined supply time, valve 243c is closed, and the supply of the first reactive gas is terminated.

[0049] The processing conditions for supplying the first reaction gas in this step are, for example, processing pressure: 10 to 240 Pa, preferably 80 to 150 Pa, and each gas supply time: 0.1 to 120 seconds, preferably 20 to 60 seconds.

[0050] (Step A1-1-4: Exhaust) At least one of exhausting and purging the interior of the processing chamber 201 is performed in the same procedure as in step A1-1-2.

[0051] The cycle in which steps A1-1-1 to A1-1-4 are performed in order is n １ This process is repeated several times. As a result, a second amorphous film 402 having a thickness of Ta2 and containing amorphous hafnium oxide as the first substance is formed on the surface of the wafer 200. １ is set so that the thickness Ta2 of the second amorphous film 402 becomes a desired thickness. Note that a part of the second amorphous film 402 may contain crystals of the first substance.

[0052] It is preferable to perform step A1-1 at a temperature equal to or lower than the amorphous crystallization temperature of the bulk first substance. In this case, the second amorphous film 402 can be formed at an even lower temperature, making it easier to suppress the effects of heat on the wafer 200. Alternatively, step A1-1 may be performed at a temperature higher than the amorphous crystallization temperature of the bulk first substance to form a film containing crystals of the first substance as a film corresponding to the above-mentioned second amorphous film 402. In this case, step A1-2 may be omitted. Even in this case, at least some of the effects of the first embodiment can be obtained.

[0053] (Step A1-2) In step A1-2, at least a portion of the amorphous material in second amorphous film 402 is crystallized to form second crystalline film 302 having a thickness Tc2 and including crystallized hafnium oxide, as shown in Step A1-2 of Fig. 5. Hereinafter, step A1-2 will be described as a case in which a process of heating wafer 200 to a predetermined temperature in an inert gas atmosphere and maintaining this state for a predetermined time is performed.

[0054] Valves 243i to 243k are opened to allow the inert gas to flow into the gas supply pipes 232i to 232k. The flow rate of the inert gas is adjusted by MFCs 241i to 241k, and the inert gas is supplied into the processing chamber 201 via nozzles 249a to 249c. In this way, the processing chamber 201 is filled with an inert gas atmosphere, and the temperature of the wafers 200 is maintained at a predetermined temperature for a predetermined processing time.

[0055] The processing conditions for this step are, for example, processing temperature: 500 to 1000° C., processing pressure: 10 to 100,000 Pa, and supply time: 10 to 60 seconds.

[0056] By performing step A1-2 to crystallize the amorphous phase in the second amorphous film, it is possible to increase the proportion of the crystalline phase in the first mixture film 501. In other words, by performing step A1-2, it is possible to form a film with a higher dielectric constant.

[0057] In step A1-2, it is preferable to maintain the temperature of the wafer 200 at or above the amorphous crystallization temperature of the bulk first substance. In this case, the crystallization of the second amorphous film 402 can proceed in a shorter time, thereby improving throughput.

[0058] (Step A2) In step A2, at least a part of the second crystalline film 302 is etched to form a first crystalline film 301 having a thickness Tc1 as shown in Step A2 of Fig. 5. Thereafter, as shown in Fig. 4(B), as step A2, a cycle including step A2-1 (Step A2-1), step A2-2 (Step A2-2), step A2-3 (Step A2-3), and step A2-4 (Step A2-4) is repeated a predetermined number of times (n ２ times, n ２ Here, an example will be described in which the second crystalline film 302 is etched by performing a step A2 in which a modified layer having a thickness equivalent to several atomic layers is formed on the surface of the material to be etched using a modifying gas, and then a removal gas is used to remove the modified layer.

[0059] (Step A2-1: Supply of first modifying gas) The valve 243e is opened, and a fluorine (F)-containing gas serving as a first modifying gas is allowed to flow into the gas supply pipe 232e. The flow rate of the first modifying gas is adjusted by the MFC 241e, and the first modifying gas is supplied to the wafers 200 via the nozzle 249c. After the first modifying gas has been supplied for a predetermined supply time, the valve 243e is closed, and the supply of the first modifying gas is terminated.

[0060] Examples of processing conditions for supplying the first modifying gas in this step include: processing temperature: 150 to 350°C, preferably 250 to 350°C processing pressure: 10 to 5000 Pa, preferably 2000 to 3000 Pa supply time: 1 to 600 seconds, preferably 260 to 480 seconds. In the following description, the processing temperatures in steps A2-1 to A2-4 are substantially the same.

[0061] (Step A2-2: Exhaust) At least one of exhausting and purging the interior of the processing chamber 201 is performed in the same procedure as in step A1-1-2.

[0062] (Step A2-3: Supply of first removal gas) The valve 243g is opened, and a chlorine (Cl)-containing gas as a first removal gas is flowed into the gas supply pipe 232g. The flow rate of the first removal gas is adjusted by the MFC 241g, and the first removal gas is supplied to the wafer 200 via the nozzle 249c. After the first removal gas is supplied for a predetermined supply time, the valve 243g is closed, and the supply of the first removal gas is terminated.

[0063] Examples of processing conditions for supplying the first removal gas in this step include: processing pressure: 10 to 5000 Pa, preferably 2000 to 3000 Pa; and supply time: 1 to 600 seconds, preferably 60 to 360 seconds.

[0064] (Step A2-4: Exhaust) At least one of exhausting and purging the interior of the processing chamber 201 is performed in the same procedure as in step A1-1-2.

[0065] A cycle in which step A2-1, step A2-2, step A2-3 and step A2-4 are performed in order is n ２ This etchs at least a portion of the second crystalline film 302, forming a first crystalline film 301 with a thickness of Tc1.

[0066] In step A2, it is preferable that at least a portion of the second crystalline film is etched by the ALE method. Generally, in the ALE method, etching proceeds by several atomic layers per cycle, and the thickness of the portion of the target material removed (etching amount) increases in proportion to the number of cycles (number of cycles). For this reason, when etching by the ALE method is used, it is easy to fine-tune the etching amount by increasing or decreasing the number of cycles, making it easier to form a thinner first crystalline film 301. Therefore, it is easier to form an even thinner film.

[0067] (Step B) In Step B, a first mixed film 501 having a first thickness Tm1 is formed as shown in Step B2 of Fig. 5 by a process including a step of forming a first amorphous film 401 containing an amorphous hafnium oxide as a second substance on the first crystalline film 301. Hereinafter, an example in which Step B1 and Step B2 are performed as Step B will be described.

[0068] 5, a first amorphous film 401 having a thickness Ta1 is formed on the first crystalline film 301, and a second mixed film 502 having a second thickness Tm2 greater than the first thickness Tm1 is formed. In the following description, the thickness Ta1 is the distance from the surface of the first crystalline film 301 to the surface of the first amorphous film 401 at the end of step B1, i.e., the difference between the second thickness Tm2 and the thickness Tc1, as shown in Step B1 of FIG.

[0069] The first amorphous film 401 is formed, for example, by supplying a second film-forming gas to the wafer 200 as a film-forming gas. An example of forming the first amorphous film 401 using a second source gas as one of the second film-forming gases and a second reactive gas as one of the second film-forming gases will be described below. Specifically, as shown in FIG. 4C, as step B1, a cycle including step B1-1 (Step B1-1), step B1-2 (Step B1-2), step B1-3 (Step B1-3), and step B1-4 (Step B1-4) is repeated a predetermined number of times (n ３ times, n ３ is an integer of 1 or more) will be described.

[0070] (Step B1-1: Supply of Second Source Gas) The valve 243b is opened, and a Hf-containing gas serving as a second source gas is supplied into the gas supply pipe 232b. The flow rate of the second source gas is adjusted by the MFC 241b, and the second source gas is supplied to the wafer 200 via the nozzle 249a. After the second modifying gas is supplied for a predetermined supply time, the valve 243b is closed, and the supply of the second source gas is terminated. The processing conditions for supplying the second source gas in this step may be, for example, the same as those described in step A1-1-1. In the following description, the processing temperatures in steps B1-1 to B1-4 are assumed to be substantially the same.

[0071] (Step B1-2: Exhaust) At least one of exhausting and purging the interior of the processing chamber 201 is performed in the same manner as in step A1-1-2.

[0072] (Step B1-3: Supply of second reactive gas) Valve 243d is opened, and an oxidizing gas as a second reactive gas is flowed into gas supply pipe 232d. The flow rate of the second reactive gas is adjusted by MFC 241d, and the second reactive gas is supplied to wafer 200 via nozzle 249b. After supplying the second reactive gas for a predetermined supply time, valve 243b is closed, and the supply of the second reactive gas is terminated. The processing conditions for supplying the second reactive gas in this step can be, for example, the same as the processing conditions described in step A1-1-3.

[0073] (Step B1-4: Exhaust) At least one of exhausting and purging the interior of the processing chamber 201 is performed in the same manner as in step A1-1-2.

[0074] A cycle in which step B1-1, step B1-2, step B1-3 and step B1-4 are performed in order is n ３ Do this n times. ３is set so that the thickness Ta1 of the first amorphous film 401 becomes a desired thickness. As a result, the first amorphous film 401 containing amorphous hafnium oxide as the second material is formed on the first crystalline film 301 (or on the surface of the wafer 200). That is, a second mixture film 502 having a second thickness Tm2 and containing the crystallized first material and the amorphous second material is formed. Note that a portion of the first amorphous film 401 may contain crystals of the second material.

[0075] It is also possible to adjust the processing conditions in step B1 to form a film having a first thickness Tm1 containing a crystallized first substance and an amorphous second substance as a film corresponding to the second mixture film 502. In this case, step B2 may be omitted, and only step B1 may be performed as step B. Even in this case, it is possible to obtain at least some of the effects of the first embodiment.

[0076] (Step B2) In step B2, the second mixture film 502 is etched to form a first mixture film 501 having a first thickness Tm1 as shown in step B2 of Fig. 5. Thereafter, as shown in Fig. 4(D), as step B2, a cycle including step B2-1 (Step B2-1), step B2-2 (Step B2-2), step B2-3 (Step B2-3), and step B2-4 (Step B2-4) is repeated a predetermined number of times (n ４ times, n ４ In this example, the second mixture film 502 is etched by performing a step B2 (where B is an integer of 1 or more). That is, in step B2, at least a part of the second mixture film 502 is etched by the ALE method.

[0077] (Step B2-1: Supply of Second Modifying Gas) The valve 243f is opened, and an F-containing gas serving as a second modifying gas is allowed to flow into the gas supply pipe 232f. The flow rate of the second modifying gas is adjusted by the MFC 241f, and the second modifying gas is supplied to the wafer 200 via the nozzle 249c. After the first modifying gas is supplied for a predetermined supply time, the valve 243f is closed, and the supply of the second modifying gas is terminated. The processing conditions for supplying the second modifying gas in this step may be, for example, the same as those described in step A2-1. In the following description, the processing temperatures in steps B2-1 to B2-4 are assumed to be substantially the same.

[0078] (Step B2-2: Exhaust) In the same procedure as in step A1-1-2, at least one of exhausting and purging the interior of the processing chamber 201 is performed.

[0079] (Step B2-3: Supply of second removal gas) The valve 243h is opened, and a Cl-containing gas as a second removal gas is flowed into the gas supply pipe 232h. The flow rate of the second removal gas is adjusted by the MFC 241h, and the second removal gas is supplied to the wafer 200 via the nozzle 249h. After the second removal gas is supplied for a predetermined supply time, the valve 243h is closed, and the supply of the second removal gas is terminated. The processing conditions for supplying the second removal gas in this step may be, for example, the same as the processing conditions described in step A2-3.

[0080] (Step B2-4: Exhaust) At least one of exhausting and purging the interior of the processing chamber 201 is performed in the same manner as in step A1-1-2.

[0081] A cycle in which step B2-1, step B2-2, step B2-3 and step B2-4 are performed in order is n ４ This etchs at least a part of the mixture film 502 having the second thickness Tm2, ​​thereby forming the mixture film 501 having the first thickness Tm1.

[0082] Since an amorphous film is more easily etched than a crystalline film, the etching rate is less likely to vary within the film than with a crystalline film. Therefore, by etching the second mixture film 502 to the second thickness Tm2 that is greater than the first thickness Tm1, as in steps B1 and B2, a first mixture film 501 with higher flatness can be formed.

[0083] In step B2, for the same reason as in step A2, it is preferable to etch at least a part of the second mixture film 502 by the ALE method. This makes it easier to form a thinner first mixture film 501, which makes it easier to form a thinner film.

[0084] As described above, by the film formation process that performs steps A and B, a first mixture film 500 containing crystallized hafnium oxide and amorphous hafnium oxide and having a first thickness (e.g., 1 nm) can be formed on the wafer 200 substrate.

[0085] The throughput in the first mixture film forming process, which is set in step C, will be described below.

[0086] The first thickness Tm1 of the first mixture film 501 is determined by the second thickness Tm2 of the second mixture film 502 and the thickness of the second mixture film 502 etched in step B2. Herein, the thickness of the second mixture film 502 etched in step B2 is the amount obtained by subtracting the thickness Tm1 from the thickness Tm2. Hereinafter, this amount will be expressed as (Tm2 - Tm1). Furthermore, the second thickness Tm2 is determined by the thickness Tc1 of the first crystalline film 301 prepared in step A and the thickness Ta1 of the first amorphous film 401 formed in step B1. Furthermore, the thickness Tc1 is determined by the thickness Tc2 of the second crystalline film 302 prepared in step A1 and the thickness (Tc2 - Tc1) of the first crystalline film 301 etched in step A2. Furthermore, thickness Tc2 can be considered to be substantially the same as thickness Ta2 of second amorphous film 402 prepared in step A1-1. For these reasons, (Tm2-Tm1), thickness Ta1, thickness Tc1, thickness Ta2, and (Tc2-Tc1) may each be included in the processing amount related to first thickness Tm1.

[0087] Here, thickness Ta1 can be increased by increasing the amount of the second deposition gas exposed to wafer 200 throughout step B1 (hereinafter referred to as the exposure amount of the second deposition gas in step B1). Therefore, the exposure amount of the second deposition gas in step B1 may be included in the process volume related to first thickness Tm1. Similarly, the exposure amount of the first deposition gas in step A1-1 may be included in the process volume related to first thickness Tm1. A similar relationship also holds for (Tc2-Tc1) and (Tm2-Tm1). That is, by increasing the exposure amount of the first etching gas in step A2, (Tc2-Tc1) can be increased. Furthermore, by increasing the exposure amount of the second etching gas in step B2, (Tm2-Tm1) can be increased. Therefore, the exposure amounts of the first etching gas in step A2 and the second etching gas in step B2 may be included in the process volume related to first thickness Tm1.

[0088] Here, when multiple types of gases are used as the second deposition gas as in the example of step B1 described above, the exposure amount of the second deposition gas in step B1 can be increased by increasing the exposure amount of at least one type of gas. Therefore, the exposure amount of the second source gas in step B1-1, the exposure amount of the second reactive gas in step B1-3, and the number of times n ３ Similarly, at least one of the exposure amount of the first source gas in step A1-1-1, the exposure amount of the first reaction gas in step A1-1-3, and the number of times n １ At least one of the exposure amount of the first modifying gas in step A2-1, the exposure amount of the first removal gas in step A2-3, and the number of times n ２ At least one of the exposure amount of the first modifying gas in step B2-1, the exposure amount of the first removal gas in step B2-3, and the number of times n ４ may be included in the processing amount associated with the first thickness Tm1.

[0089] Here, the "exposure amount of gas Y in step X" can be increased by at least one of increasing the partial pressure of gas Y in the space (e.g., the process chamber 201) where the wafer 200 is present in step X and increasing the supply time of gas Y in step X. The partial pressure of gas Y in step X can be increased by increasing the pressure in the process chamber 201 and increasing the molar fraction of gas Y. The molar fraction of gas Y in step X can be increased by increasing the amount (supply flow rate) of gas Y supplied into the process chamber 201 in step X. Therefore, the supply time, processing pressure, and supply flow rate of the first source gas in step A1-1-1, the first reaction gas in step A1-1-3, the first modifying gas in step A2-1, the first removal gas in step A2-3, the second source gas in step B1-1, the second reaction gas in step B1-3, the second modifying gas in step B2-1, and the second removal gas in step B2-3 may be included in the processing volume related to the first thickness Tm1.

[0090] Here, it is preferable to set the processing temperature in step B1 higher than the processing temperature in step A1-1. This makes it easier to form a dense first amorphous film 401, thereby improving the insulating properties of the mixture film 500. Furthermore, as shown in Step A2 of FIG. 5, the surface area of ​​the crystalline film after etching tends to increase as the flatness decreases. Therefore, it is preferable to set the supply time of the second source gas in step B1-1 longer than the supply time of the first source gas in step A1-1. This makes it easier to form a dense first amorphous film 401, thereby improving the insulating properties of the mixture film 500.

[0091] In addition, it is preferable to set the exposure amount of the second film formation gas to the wafer 200 in step B1 higher than the exposure amount of the first film formation gas to the wafer 200 in step A1-1, which makes it easier to form a dense first amorphous film 401, thereby improving the insulating properties of the mixture film 500.

[0092] (After-purge and atmospheric pressure return) An inert gas is supplied into the processing chamber 201 from each of the gas supply pipes 232i to 232k and exhausted through the exhaust pipe 231. This purges the processing chamber 201 (after-purge). Thereafter, the atmosphere in the processing chamber 201 is replaced with the inert gas (inert gas replacement), and the pressure in the processing chamber 201 is returned to normal pressure (atmospheric pressure return).

[0093] (Wafer Unloading) Thereafter, the seal cap 219 is lowered by the boat elevator 115, and the bottom end of the reaction tube 203 is opened. Then, the processed wafers 200, supported by the boat 217, are unloaded from the bottom end of the reaction tube 203 to the outside of the reaction tube 203 (boat unloading). The processed wafers 200 are removed from the boat 217 (wafer discharging).

[0094] (3) Effects of the First Embodiment In addition to the effects described above, at least one of the following effects can be obtained.

[0095] (a) The first mixture film 501 can be formed as a film having desired properties (for example, sufficient thinness, high dielectric constant, high insulating properties, etc.), as will be described below.

[0096] As described above, the first thickness Tm1 is set so that the crystallization temperature of the amorphous film of the first material having the first thickness Tm1 is higher than the crystallization temperature of the amorphous material of the bulk first material. Furthermore, because the first mixture film 501 contains crystalline particles, it exhibits a higher dielectric constant than an amorphous film having the first thickness Tm1. Furthermore, in the first mixture film 501, the grain boundaries in the first crystalline film are filled with the amorphous material of the second material, so it exhibits higher insulating properties than a crystalline film having the first thickness Tm1. Therefore, according to the first embodiment, the first mixture film 501 can be formed as a film having desired characteristics (e.g., sufficient thinness, high dielectric constant, high insulating properties, etc.).

[0097] (b) By carrying out step A2, a thin film exhibiting high insulating properties can be formed, as will be explained below.

[0098] Generally, etching a crystalline film can form a thinner crystalline film. In this case, amorphous and relatively small crystalline grains in the crystalline film are more susceptible to etching than relatively large crystalline grains. Furthermore, etching of a crystalline film proceeds from the interface between the crystalline grains at the grain boundaries, i.e., the grain boundaries, which tend to widen the grain boundaries. For these reasons, forming a thin crystalline film by etching increases the likelihood of leakage current flowing through the grain boundaries, further reducing the insulating properties. In the first embodiment, in step A2, at least a portion of the second crystalline film 302 is etched to form the first crystalline film 301, and in step B1, the first amorphous film 401 is formed on the first crystalline film 301. This fills the grain boundaries in the first crystalline film 301 with the amorphous second material, thereby improving the insulating properties. Therefore, by performing step A2, a thin film exhibiting high insulating properties can be formed.

[0099] (c) The second substance may be a substance different from the first substance. This will be explained below.

[0100] For example, consider the case of forming a first mixture film 501 containing crystalline hafnium oxide as the first material and amorphous aluminum oxide as the second material. Hafnium oxide has a higher dielectric constant than aluminum oxide. Furthermore, because aluminum oxide has a larger band gap than hafnium oxide, an aluminum oxide film has better insulating properties than a hafnium oxide film. In this case, a first mixture film 501 can be formed that has both a high dielectric constant and high insulating properties. In this way, by using a material different from the first material as the second material, the film characteristics can be improved.

[0101] When a material different from the first material is used as the second material, it is preferable to select the first material and the second material such that the crystalline film of the first material exhibits a higher dielectric constant than the crystalline film of the second material. This can further improve the dielectric constant of the first mixture film 501. When a material different from the first material is used as the second material, it is preferable to select the first material and the second material such that the band gap of the second material is larger than the band gap of the first material. This can further improve the insulating properties of the first mixture film 501.

[0102] (d) Metal oxides tend to exhibit high dielectric constants. Therefore, it is preferable that at least one of the first substance and the second substance is a metal oxide, and it is even more preferable that both the first substance and the second substance are metal oxides. This allows for the formation of a film with a further improved dielectric constant, sufficient thinness, and high insulating properties. This can therefore improve the performance of semiconductor devices.

[0103] (e) The thickness of an amorphous film that has a higher crystallization temperature than bulk amorphous varies depending on the material. However, an amorphous film with a thickness of 2 nm or less is likely to have a higher crystallization temperature than bulk amorphous, regardless of the constituent material. Furthermore, when the thickness TC1 of the first crystallized film 301 is 0.5 nm or more and the first thickness TC1 of the first mixture film 501 is 0.5 nm or more, the proportion of crystalline phases in the first mixture film 501 is likely to be large, regardless of the constituent material. Therefore, when the first mixture film 501 is formed with a first thickness TC1 of 0.5 nm or more and 2 nm or less, the technology disclosed herein can form a film that is sufficiently thin, has a high dielectric constant, and is highly insulating.

[0104] Second Embodiment The second embodiment will be described below, focusing on differences from the first embodiment. The second embodiment differs from the first embodiment in that step D is performed after the first mixture film formation process of the first embodiment. Elements not specifically described in the following description (e.g., elements related to the configuration of the substrate processing apparatus and the substrate processing process) are assumed to be similar to those in the first embodiment. Furthermore, the second embodiment also achieves at least some of the effects described in the first embodiment. Even if not specifically described in the second embodiment, at least some of the elements that contribute to improving the properties of the first mixture film in the first embodiment also contribute to improving the properties of the third mixture film 303 in the second embodiment.

[0105] (Step D) In ​​Step D, at least a portion of the first amorphous film 401 is crystallized to form a third crystalline film 303 as shown in Step D of FIG. 5 , thereby forming a third mixed film 503 having a third thickness Tm3, which includes at least a portion of the first crystalline film 301 and at least a portion of the third crystalline film 303. The third crystalline film 303 may be substantially composed of a crystallized second material, and may contain a trace amount of amorphous. The third mixed film 503 may be substantially composed of a crystallized first material and a crystallized second material, and may contain a trace amount of amorphous first material and amorphous second material. Hereinafter, Step D will be described, in which the wafer 200 is heated to a predetermined temperature in an inert gas atmosphere and maintained for a predetermined period of time.

[0106] For example, the process chamber 201 is filled with an inert gas atmosphere in the same manner as in step A1-2, and the temperature of the wafer 200 is maintained at a predetermined temperature for a predetermined processing time. The process conditions for this step can be the same as those for step A1-2.

[0107] The third mixture film 503 has a thickness similar to that of the first mixture film 501. The proportion of the crystalline phase in the third mixture film 503 is higher than the proportion of the crystalline phase in the first mixture film 501. Furthermore, since crystallization of the second substance in the first amorphous film 401 is likely to proceed on the surface of the crystals of the first substance in the first crystalline film 301, a crystalline phase is also likely to form in locations corresponding to the grain boundaries of the first crystalline film 301. For these reasons, by performing step D, a third mixture film 503 can be formed that is sufficiently thin and has an even higher dielectric constant and even higher insulating properties. In other words, it becomes even easier to form a film with desired characteristics.

[0108] In step D, it is preferable to maintain the temperature of the wafer 200 at or above the amorphous crystallization temperature of the bulk second material. This allows the crystallization of the first amorphous film 401 to proceed in a shorter time, thereby improving throughput. Step D may also be performed under conditions that allow the crystallization of the amorphous material that may be contained in the first crystalline film 301 to proceed. This increases the proportion of the crystalline phase occupying the interior of the third mixture film 503, thereby further improving the dielectric constant of the third mixture film 503. In other words, it becomes easier to form a film having the desired characteristics.

[0109] When step D is performed, a third mixture film 503 containing crystals of the second material can be formed. Therefore, when a material different from the first material is used as the second material, the first material and the second material may be selected so that the crystalline film of the second material exhibits a higher dielectric constant than the crystalline film of the first material. Even in such a case, a third mixture film 503 can be formed that is sufficiently thin and has an even higher dielectric constant and even higher insulating properties. In other words, it becomes easier to form a film with desired properties.

[0110] Other Aspects of the Present Disclosure The above describes specific aspects of the present disclosure. However, the present disclosure is not limited to the above aspects and can be modified in various ways without departing from the spirit and scope of the present disclosure.

[0111] In the explanation of the first and second embodiments, the case where step A, step B, and step D are performed in the same processing chamber (i.e., in-situ) has been used as an example. However, at least a part of step A and / or step D may be performed in a processing chamber different from the processing chamber where step B is performed. Furthermore, at least a part of step A and / or step D may be performed in a substrate processing apparatus different from the substrate processing apparatus where step B is performed. In these cases, the same effects as those described above can be obtained.

[0112] It is preferable that recipes used for substrate processing are individually prepared according to the processing content and stored in the storage device 121c via an electric communication line or the external storage device 123. When starting substrate processing, the CPU 121a preferably selects an appropriate recipe from the multiple recipes stored in the storage device 121c according to the processing content. This enables the substrate processing device to process films of various film types, composition ratios, film qualities, and film thicknesses with good reproducibility. This also reduces the burden on the operator, avoids operational errors, and allows substrate processing to be started quickly.

[0113] The above-mentioned recipes may not necessarily be newly created, but may be prepared by modifying an existing recipe already installed in the substrate processing apparatus. When modifying a recipe, the modified recipe may be installed in the substrate processing apparatus via an electric communication line or a recording medium on which the modified recipe is recorded. Alternatively, an existing recipe already installed in the substrate processing apparatus may be directly modified by operating the input / output device 122 provided in the existing substrate processing apparatus.

[0114] Furthermore, in the above-described embodiment, an example has been described in which a batch-type substrate processing apparatus that processes multiple substrates at a time is used. The present disclosure is not limited to the above-described embodiment. For example, the present disclosure can be suitably applied to a case in which a single-wafer-type substrate processing apparatus that processes one or several substrates at a time is used. Furthermore, in the above-described embodiment, an example has been described in which a substrate processing apparatus having a hot-wall processing furnace is used. The present disclosure is not limited to the above-described embodiment. For example, the present disclosure can be suitably applied to a case in which a substrate processing apparatus having a cold-wall processing furnace is used. Even when using these substrate processing apparatuses, processing can be performed using the same processing procedures and processing conditions as in the above-described embodiment and modified examples, and the same effects as in the above-described embodiment and modified examples can be obtained. Furthermore, the above-described embodiment and modified examples can be used in appropriate combination. The processing procedures and processing conditions in this case can be, for example, the same as the processing procedures and processing conditions in the above-described embodiment and modified examples.

[0115] 200: wafer (substrate), 301: first crystalline film, 401: first amorphous film, 501: first mixed film, Tm1: first thickness

Claims

1. A substrate processing method comprising: (a) preparing a substrate having a first crystalline film formed on its surface, the first crystalline film including a crystallized first material; (b) forming a first amorphous film including an amorphous second material on the first crystalline film; and (c) setting, prior to the first mixed film forming step, a processing amount in the first mixed film forming step that is related to the first thickness, so that the crystallization temperature of the amorphous film of the first material and the amorphous second material is higher than the amorphous crystallization temperature of the bulk first material.

2. The substrate processing method according to claim 1, wherein (a) comprises the steps of: (a1) preparing the substrate on whose surface a second crystalline film containing the crystallized first substance and having a thickness greater than that of the first crystalline film is formed; and (a2) etching at least a portion of the second crystalline film to form the first crystalline film.

3. The substrate processing method according to claim 2, wherein (a1) comprises the steps of: (a1-1) preparing the substrate having a second amorphous film formed on its surface, the second amorphous film containing the amorphous first substance; and (a1-2) crystallizing at least a portion of the amorphous material in the second amorphous film to form the second crystalline film.

4. The substrate processing method according to claim 3, wherein (a1-1) is a step of forming the second amorphous film on the surface of the substrate, and (b) is performed at a temperature higher than that of (a1-1).

5. The substrate processing method of claim 3, comprising the steps of: (a1-1) forming the second amorphous film on the substrate by supplying a first film formation gas to the substrate; (b) forming the first amorphous film on the substrate by supplying a second film formation gas to the substrate; and (b) increasing the amount of exposure of the second film formation gas to the substrate than the amount of exposure of the first film formation gas to the substrate in (a1-1).

6. The substrate processing method according to claim 3, wherein in (a1-2), the temperature of the substrate is maintained at or above the amorphous crystallization temperature of the bulk of the first substance.

7. The substrate processing method according to claim 2, wherein in (a2), at least a portion of the second crystal film is etched by atomic layer etching.

8. A substrate processing method according to any one of claims 1 to 7, wherein in (b), the first amorphous film is formed by supplying a second film formation gas to the substrate, and the processing amount includes an exposure amount of the second film formation gas to the substrate in (b).

9. A substrate processing method according to any one of claims 1 to 7, wherein (b) comprises the steps of: (b1) forming the first amorphous film on the first crystalline film to form a second mixed film containing the crystallized first material and the amorphous second material, and having a second thickness greater than the first thickness; and (b2) etching the second mixed film to form the first mixed film.

10. The substrate processing method according to claim 9, wherein in (b2), the first amorphous film is formed by supplying an etching gas to the substrate, and the processing amount includes an exposure amount of the etching gas to the substrate in (b2).

11. The substrate processing method according to claim 9, wherein in (b2), at least a portion of the second mixture film is etched by atomic layer etching.

12. A substrate processing method according to any one of claims 1 to 7, further comprising the step of: (d) forming a third crystalline film by crystallizing at least a portion of the first amorphous film in the first mixed film, thereby forming a third mixed film containing at least a portion of the first crystalline film and at least a portion of the third crystalline film.

13. The method of claim 12, wherein in (d), the temperature of the substrate is maintained at or above the amorphous crystallization temperature of the bulk of the second material.

14. The substrate processing method according to any one of claims 1 to 7, wherein a substance different from the first substance is used as the second substance.

15. The substrate processing method according to claim 14, wherein the first material and the second material are selected such that a crystalline film of the first material exhibits a higher dielectric constant than a crystalline film of the second material.

16. The substrate processing method according to claim 14, wherein the first material and the second material are selected such that the band gap of the second material is larger than the band gap of the first material.

17. The substrate processing method according to any one of claims 1 to 7, wherein one or both of the first substance and the second substance is a metal oxide.

18. A method for manufacturing a semiconductor device, comprising: (a) preparing a substrate having a first crystalline film formed on its surface, the first crystalline film including a crystallized first material; (b) forming a first amorphous film on the first crystalline film, the first amorphous film including an amorphous second material; and (c) setting, prior to the first mixed film forming step, a processing amount in the first mixed film forming step that is related to the first thickness, so that the crystallization temperature of the amorphous film of the first material and the first thickness is higher than the amorphous crystallization temperature of the bulk first material.

19. A substrate processing apparatus comprising: a film formation mechanism for forming a film containing a second material on a substrate; and a control unit configured to be able to control the film formation mechanism to perform: (a) a process for preparing the substrate having a first crystalline film containing a crystallized first material formed on its surface; (b) a process for forming a first amorphous film containing the amorphous second material on the first crystalline film; and a first mixed film formation process for forming a first mixed film of a first thickness on the substrate, the first mixed film containing the crystallized first material and the amorphous second material; and (c) a process for setting a processing amount in the first mixed film formation process related to the first thickness before the first mixed film formation process, so that the crystallization temperature of the amorphous film of the first material of the first thickness is higher than the amorphous crystallization temperature of the first material in bulk.

20. A program that causes a substrate processing apparatus to execute, by a computer, the following steps: (a) a step of preparing a substrate having a first crystalline film formed on its surface, the first crystalline film including a crystallized first substance; (b) a step of forming a first amorphous film including an amorphous second substance on the first crystalline film; and (c) a step of setting, before the first mixed film formation step, a processing amount in the first mixed film formation step that is related to the first thickness, so that the crystallization temperature of the amorphous film of the first substance of the first thickness is higher than the amorphous crystallization temperature of the bulk of the first substance.

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