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

Abstract

Provided is a technique with which it is possible to control the orientation of crystal particles in a film (or in a layer).　The method includes a step for forming a film on a substrate by performing a cycle for forming layers on the substrate a prescribed number of times by performing (a) a step for supplying a raw material gas containing a halogen element to the substrate, and (b) a step for supplying a reaction gas to the substrate, the cycles being performed under a prescribed formation condition on the basis of a prescribed relationship between the amount of the halogen element included in the layer and the proportion of the film occupied by crystal particles oriented in a prescribed crystal plane.

Description

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

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

[0002] As one step in a substrate processing process (a process for manufacturing a semiconductor device), a film may be formed on a substrate by supplying a source gas containing a halogen element and a reactive gas to the substrate (see, for example, Patent Document 1).

[0003] International Publication No. 2019 / 058608

[0004] The present disclosure provides a technique that makes it possible to control the orientation of crystal grains in a film (or layer).

[0005] According to one aspect of the present disclosure, there is provided a technology comprising: (a) a step of supplying a raw material gas containing a halogen element to a substrate; and (b) a step of supplying a reaction gas to the substrate; and performing a cycle of forming a layer on the substrate a predetermined number of times to form a film on the substrate, wherein the cycle is performed under formation conditions that are set based on a predetermined relationship between the amount of the halogen element contained in the layer and the proportion of crystal grains in the film that are oriented in a predetermined crystal plane.

[0006] According to the present disclosure, it is possible to control the orientation of crystal grains in a film (or layer).

[0007] FIG. 1 is a longitudinal cross-sectional view showing an outline of a substrate processing apparatus. FIG. 2 is a schematic diagram of a controller of the substrate processing apparatus, and is a block diagram showing a control system of the controller. FIG. 3 is a diagram showing the timing of gas supply in a substrate processing step. FIG. 4(A) is an image diagram of a film (or layer) formed on a substrate under conditions such that the amount of halogen element contained in the layer is increased. FIG. 4(B) is an image diagram of a film (or layer) formed on a substrate under conditions such that the amount of halogen element contained in the layer is decreased. FIG. 5 is a diagram showing the timing of gas supply in Modification 1. FIG. 6 is a diagram for explaining the timing of gas supply in the first cycle of Modifications 2 and 3. FIG. 7 is a diagram showing the flow of Modification 2. FIG. 8 is a diagram showing the flow of Modification 3.

[0008] <One Aspect of the Present Disclosure> One aspect of the present disclosure will be described below, mainly with reference to Figures 1 to 4. Note that all drawings used in the following description are schematic, and the dimensional relationships between elements, the ratios of elements, and the like shown in the drawings do not necessarily match those in reality. Furthermore, the dimensional relationships between elements, the ratios of elements, and the like do not necessarily match between multiple drawings.

[0009] (1) Configuration of the Substrate Processing Apparatus The substrate processing apparatus 10 includes a processing furnace 202 provided with a heater 207 as a heating means (heating mechanism, heating system). An outer tube 203 is disposed inside the heater 207. An O-ring 220a as a sealing member and a manifold 209 are disposed below the outer tube 203. An inner tube 204 is disposed inside the outer tube 203. The outer tube 203, the inner tube 204, and the manifold 209 mainly constitute a processing vessel (reaction vessel). A processing chamber 201 is formed inside the inner tube 204.

[0010] Nozzles 410, 420, and 430 are provided in the processing chamber 201. Gas supply pipes 310, 320, and 330 are connected to the nozzles 410, 420, and 430, respectively.

[0011] The vertical portions of the nozzles 410, 420, 430 are provided inside the preliminary chamber 201a, which is formed so as to protrude radially outward from the inner tube 204. A plurality of gas supply holes 410a, 420a, 430a are provided in the nozzles 410, 420, 430. Gas supplied to the nozzles 410, 420, 430 is supplied into the processing chamber 201 and / or to the wafer 200 from the gas supply holes 410a, 420a, 430a, respectively.

[0012] A source gas containing a halogen element as a process gas is supplied into the process chamber 201 in this order through a mass flow controller (MFC) 312, which is a flow rate controller (flow rate control section) provided in a gas supply pipe 310, a valve 314, and a nozzle 410. A reducing gas as a process gas is supplied into the process chamber 201 in this order through an MFC 322, a valve 324, and a nozzle 420 provided in a gas supply pipe 320. A reactive gas as a process gas is supplied into the process chamber 201 in this order through an MFC 332, a valve 334, and a nozzle 430 provided in a gas supply pipe 330.

[0013] The gas supply pipes 510, 520, and 530 are connected to the downstream sides of the valves 314, 324, and 334 of the gas supply pipes 310, 320, and 330, respectively. The inert gas is supplied into the processing chamber 201 sequentially via MFCs 512, 522, and 532, valves 514, 524, and 534, and nozzles 410, 420, and 430, which are provided in the gas supply pipes 510, 520, and 530, respectively.

[0014] A process gas supply system is mainly composed of the gas supply pipes 310, 320, and 330, the MFCs 312, 322, and 332, the valves 314, 324, and 334, and the nozzles 410, 420, and 430. Only the nozzles 410, 420, and 430 may be considered to be the process gas supply system. Alternatively, the process gas supply system may simply be referred to as a gas supply system. When a source gas is flowed from the gas supply pipe 310, the source gas supply system is mainly composed of the gas supply pipe 310, the MFC 312, and the valve 314. The nozzle 410 may be considered to be included in the source gas supply system. When a reducing gas is flowed from the gas supply pipe 320, the reducing gas supply system is mainly composed of the gas supply pipe 320, the MFC 322, and the valve 324. The nozzle 420 may be considered to be included in the reducing gas supply system. Furthermore, when a reactive gas is mainly flowed from the gas supply pipe 330, a reactive gas supply system is configured mainly by the gas supply pipe 330, the MFC 332, and the valve 334. The nozzle 430 may also be considered to be included in the reactive gas supply system. An inert gas supply system is mainly configured mainly by the gas supply pipes 510, 520, and 530, the MFCs 512, 522, and 532, and the valves 514, 524, and 534.

[0015] The exhaust hole (exhaust port) 204a is a through-hole formed in the sidewall of the inner tube 204. The gas supplied into the processing chamber 201 flows horizontally over the wafers 200, and is then exhausted to the outside of the processing furnace 202 via the exhaust hole 204a, an exhaust path 206 formed between the inner tube 204 and the outer tube 203, and an exhaust pipe 231, in that order.

[0016] The exhaust pipe 231 is connected, in order from upstream, to a pressure sensor 245 serving as a pressure detector (pressure detection unit) that detects the pressure inside the processing chamber 201, an APC (Auto Pressure Controller) valve 243, and a vacuum pump 246 serving as a vacuum exhaust device. The APC valve 243 opens and closes the valve while the vacuum pump 246 is operating, thereby enabling and stopping the evacuation of the processing chamber 201. Furthermore, the pressure inside the processing chamber 201 can be adjusted by adjusting the valve opening while the vacuum pump 246 is operating. An exhaust system is mainly composed of the exhaust hole 204a, the exhaust path 206, the exhaust pipe 231, the APC valve 243, and the pressure sensor 245. The vacuum pump 246 may be included in the exhaust system.

[0017] An O-ring 220b serving as a sealing member and a seal cap 219 capable of closing the lower end opening of the manifold 209 are provided below the manifold 209. The seal cap 219 is provided with a rotation mechanism 267 configured to rotate the boat 217 and the wafers 200 by rotating a rotation shaft 255. A boat elevator 115 serving as a lifting mechanism is configured to lift and lower the seal cap 219, thereby enabling the boat 217 to be loaded into and unloaded from the processing chamber 201.

[0018] The boat 217, which serves as a substrate support, supports a plurality of wafers 200, for example, 25 to 200 wafers, in a horizontal position. A heat insulating cylinder 218 is provided at the bottom of the boat 217. Note that in this disclosure, when a numerical range such as "25 to 200 wafers" is expressed, it means that the lower limit and upper limit are included in the range. Thus, for example, "25 to 200 wafers" means "25 or more and 200 or less." The same applies to other numerical ranges.

[0019] A temperature sensor 263 serving as a temperature detector is installed inside the inner tube 204. The amount of power supplied to the heater 207 is adjusted based on temperature information detected by the temperature sensor 263, so that the temperature distribution inside the processing chamber 201 is set to a desired value.

[0020] 2, the controller 121, which is a control unit (control means), 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 be able to exchange data with the CPU 121a via an internal bus. An input / output device 122, which is configured as, for example, a touch panel, is connected to the controller 121.

[0021] The storage device 121c is composed of, for example, a flash memory, an HDD (Hard Disk Drive), etc. The storage device 121c readably stores a control program for controlling the operation of the substrate processing apparatus, a process recipe describing the procedures and conditions of a substrate processing method or a semiconductor device manufacturing method (described later), and the like. The process recipe is a combination of processes (steps) in a semiconductor device manufacturing method (described later) that are executed by the controller 121 to obtain a predetermined result, and functions as a program. Hereinafter, the process recipe, control program, etc. are collectively referred to simply as a program. In this specification, the term "program" may refer to a process recipe alone, a control program alone, or a combination of a process recipe and a control program. The RAM 121b is configured as a memory area (work area) in which programs, data, etc. read by the CPU 121a are temporarily stored.

[0022] The I / O port 121d is connected to the above-mentioned MFCs 312, 322, 332, 512, 522, 532, valves 314, 324, 334, 514, 524, 534, pressure sensor 245, APC valve 243, vacuum pump 246, heater 207, temperature sensor 263, rotation mechanism 267, boat elevator 115, etc.

[0023] The CPU 121a is configured to read and execute a control program from the storage device 121c, and also to read a recipe or the like from the storage device 121c in response to an input of an operation command from the input / output device 122. The CPU 121a is configured to control, in accordance with the contents of the read recipe, the flow rate adjustment operation of various gases by the MFCs 312, 322, 332, 512, 522, and 532, the opening and closing operations of the valves 314, 324, 334, 514, 524, and 534, the opening and closing operation of the APC valve 243 and the pressure adjustment operation by the APC valve 243 based on the pressure sensor 245, the temperature adjustment operation of the heater 207 based on the temperature sensor 263, the start and stop of the vacuum pump 246, 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, the accommodation operation of the wafers 200 in the boat 217, and the like.

[0024] The controller 121 can be configured by installing the above-mentioned program stored in an external storage device 123 (e.g., a magnetic tape, a magnetic disk such as a flexible disk or a hard disk, an optical disk such as a CD or a DVD, a magneto-optical disk such as an MO, or a semiconductor memory such as a USB memory or a memory card) into a computer. 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 simply as recording media. In this specification, the recording medium may include only the storage device 121c, only the external storage device 123, or both. 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.

[0025] (2) Substrate Processing Step (Film Forming Step) As one step in the manufacturing process of a semiconductor device, an example of a step of forming a predetermined film on a wafer 200 will be described with reference to Fig. 3. In the following description, the operation of each part constituting the substrate processing apparatus 10 is controlled by a controller 121.

[0026] 3 may be referred to as follows for convenience: Similar notations will be used in the following explanations of modified examples.

[0027] (raw material gas → raw material gas + reducing gas → reducing gas → gas removal → reactive gas → gas removal) x n ⇒ predetermined film

[0028] 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".

[0029] (Wafer Loading) A plurality of wafers 200 are loaded 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. As shown in FIG. 1 , the seal cap 219 closes the lower end opening of the outer tube 203.

[0030] (Pressure Adjustment and Temperature Adjustment) The processing chamber 201 is evacuated by the vacuum pump 246 to a desired pressure (vacuum level) (evacuation operation). At this time, the pressure inside the processing chamber 201 is measured by the pressure sensor 245, and the APC valve 243 is feedback-controlled based on the measured pressure information (pressure adjustment). The processing chamber 201 is also heated by the heater 207 to a desired temperature. The rotation mechanism 267 also starts to rotate the boat 217 and the wafers 200 (rotation operation). The evacuation operation and rotation operation are continued at least until the processing of the wafers 200 is completed.

[0031] (Source gas supply, step S11) Valves 314 and 514 are opened to flow a source gas containing a halogen element into gas supply pipe 310 and an inert gas into gas supply pipe 510. The source gas and the inert gas are supplied to processing chamber 201 and wafer 200 from gas supply hole 410a of nozzle 410, and are exhausted from exhaust pipe 231. At this time, in order to prevent the source gas from entering nozzles 420 and 430, valves 524 and 534 are opened to flow the inert gas into gas supply pipes 520 and 530.

[0032] Examples of processing conditions for supplying the source gas in this step include: Processing temperature: 300 to 600°C, preferably 400 to 560°C, and more preferably 450 to 530°C Processing pressure: 1 to 3990 Pa Source gas supply flow rate: 0.1 to 2.0 slm Inert gas supply flow rate (each nozzle): 0.1 to 20 slm From the viewpoint of improving the processing speed, it is particularly preferable to set the processing temperature to be substantially the same in all steps.

[0033] In this disclosure, 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. These terms also apply to the following description.

[0034] By supplying the source gas, a layer A containing a predetermined element and a halogen element is formed on the wafer 200 (the surface base film). In the following description, the term "modified layer" is used in addition to the term "layer A." In the present disclosure, the term "layer" may be used as a general term for layer A and the modified layer, or may be used to refer to either layer A or the modified layer.

[0035] The source gas may be a gas containing a predetermined element and a halogen element. The predetermined element may be, 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), silicon (Si), etc. The halogen element may be, for example, one or more of fluorine (F), chlorine (Cl), etc. The source gas may be a gas activated by plasma or the like.

[0036] The gas containing a predetermined element and a halogen element is, for example, tungsten hexachloride (WCl ６ ), tungsten hexafluoride (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 ), dichlorosilane (SiH ２ Cl ２ ), 1,2-dichlorodisilane (Si２ H ４ Cl ２ ), 1,1,1-trichlorodisilane (Si ２ H ３ Cl ３ ), 1,1,2-trichlorodisilane (Si ２ H ３ Cl ３ ), pentachlorodisilane (Si ２ HCl ５ ), hexachlorodisilane (Si ２ Cl ６ ), tetrafluorosilane (SiF ４ As the source gas, one or more of these can be used.

[0037] The inert gas may be, for example, nitrogen (N ２ In addition to the above-mentioned gases, rare gases such as argon (Ar) gas, helium (He) gas, neon (Ne) gas, and xenon (Xe) gas can be used. One or more of these can be used as the inert gas. The same applies to the inert gas in the following description.

[0038] (Simultaneous Supply of Source Gas and Reducing Gas, Step S12) After a predetermined time has elapsed since the start of the source gas supply, for example, 0.01 to 5 seconds, valves 324 and 524 are opened to allow a reducing gas to flow into the gas supply pipe 320 and an inert gas to flow into the gas supply pipe 520. The reducing gas and the inert gas are supplied into the processing chamber 201 from the gas supply holes 420a of the nozzle 420 and exhausted from the exhaust pipe 231. Here, the supply of source gas into the processing chamber 201 has been continued since step S11. That is, the reducing gas is supplied at least partially simultaneously with the supply of the source gas. In other words, the source gas and the reducing gas are simultaneously supplied to the wafer 200. At this time, in order to prevent the source gas and the reducing gas from entering the nozzle 430, valve 534 is opened to allow an inert gas to flow into the gas supply pipe 530.

[0039] By supplying the reducing gas, at least a portion of the halogen elements contained in the layer can be removed. Also, by-products containing halogen elements before being adsorbed onto the wafers 200 can be reduced and removed from the processing chamber 201. Therefore, the amount of halogen elements contained in the layer can be controlled. Furthermore, it is possible to suppress the by-products adsorbed onto the wafers 200 from interfering with the formation of the layer, thereby improving the film formation rate.

[0040] Furthermore, by simultaneously supplying the source gas and the reducing gas, it is possible to further reduce the amount of by-products containing halogen elements that are adsorbed onto the wafers 200. As a result, it is possible to further improve the film formation rate.

[0041] Examples of processing conditions for supplying the source gas and reducing gas in this step include: processing pressure: 130 to 3990 Pa, reducing gas supply flow rate: 0.1 to 5 slm, and inert gas supply flow rate (each nozzle): 0.01 to 20 slm. Other processing conditions can be the same as the processing conditions for supplying the source gas. This step is performed for, for example, 0 to 10 seconds.

[0042] A gas that does not contain the main constituent elements of the film can be used as the reducing gas. In this case, reactions between the source gas and the reducing gas, or between the reactive gas and the reducing gas, are unlikely to occur. Therefore, the supply of the reducing gas can be started before the source gas and the reactive gas are sufficiently removed from the processing chamber 201. This can prevent an increase in processing time.

[0043] The reducing gas may be, 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 (Ge２ H ６ ) gas, trimethylaluminum ((CH ３ ) ３ Al) gas, phosphine (PH ３ ) gas, etc. can be used.

[0044] (Supply of reducing gas, step S13) After the supply of the source gas starts, for example, 0.01 to 10 seconds later, but before the supply of the reducing gas ends, the valve 314 of the gas supply pipe 310 is closed to stop the supply of the source gas. At this time, the reducing gas is supplied to the wafer 200. At this time, in order to prevent the reducing gas from entering the nozzles 410 and 430, the valves 514 and 534 are opened and an inert gas is flowed into the gas supply pipes 510 and 530.

[0045] By supplying the reducing gas after stopping the supply of the source gas, the halogen elements contained in the layer can be further removed. Therefore, the amount of halogen elements contained in the layer can be controlled. Furthermore, it is possible to suppress the inhibition of layer formation by by-products adsorbed on the wafer 200, and the film formation rate can be improved.

[0046] (Removal of Residual Gas, Step S14) After the supply of the reducing gas has started, for example, 0.01 to 10 seconds later, and after the supply of the source gas has ended, the valve 324 is closed to stop the supply of the reducing gas. At this time, the APC valve 243 of the exhaust pipe 231 is left open, and the processing chamber 201 is evacuated to a vacuum by the vacuum pump 246. This removes gas from the space in which the wafer 200 is present. At this time, the valves 514, 524, and 534 may be left open to continue supplying the inert gas into the processing chamber 201. The inert gas acts as a purge gas, and allows efficient gas removal from the processing chamber 201.

[0047] (Reactive Gas Supply, Step S15) Next, the valves 334 and 534 are opened to allow reactive gas to flow into the gas supply pipe 330 and inert gas to flow into the gas supply pipe 530. The reactive gas and inert gas are supplied into the processing chamber 201 through the gas supply holes 430a of the nozzle 430 and exhausted through the exhaust pipe 231. At this time, the reactive gas is supplied to the wafer 200. At this time, in order to prevent the reactive gas from entering the nozzles 410 and 420, the valves 514 and 524 are opened to allow the inert gas to flow into the gas supply pipes 510 and 520. The reactive gas reacts with at least a portion of the layer A on the wafer 200 to form a modified layer. In other words, the reactive gas modifies at least a portion of the layer A on the wafer 200 to form a modified layer.

[0048] Examples of processing conditions for supplying the reactive gas in this step include: processing pressure: 1 to 3990 Pa, reactive gas supply flow rate: 0.1 to 30 slm, reactive gas supply time: 0.01 to 30 seconds, and inert gas supply flow rate (each nozzle): 0.1 to 30 slm. Other processing conditions can be the same as the processing conditions for supplying the source gas.

[0049] The reactive gas may be, for example, a gas containing the above-mentioned reducing gas, an oxidizing gas containing oxygen (O), a nitriding gas containing nitrogen (N), a sulfide gas, a selenide gas, a telluride gas, or the like. One or more of these may be used as the reactive gas. A gas activated by plasma or the like may also be used as the reactive gas. For example, when a reducing gas is used as the reactive gas, a film mainly composed of the above-mentioned elemental substance can be formed on the wafer 200. Furthermore, when any one of an oxidizing gas, a nitriding gas, a sulfide gas, a selenide gas, or a telluride gas is used as the reactive gas, any one of an oxide film, a nitride film, a sulfide film, a selenide film, or a telluride film containing the above-mentioned element can be formed on the wafer 200.

[0050] The oxidizing gas may be, for example, oxygen (O ２ ), ozone (O ３ ), water vapor (H ２ O), H ２ and O ２ mixed gas, hydrogen peroxide (H２ O ２ ), nitrous oxide (N ２ O), etc. As the nitriding gas, for example, ammonia (NH ３ ) gas, diazene (N ２ H ２ ) gas, hydrazine (N ２ H ４ ) gas, N ３ H ８ The sulfur gas may be, for example, sulfane (H ２ S), disulfane (H ２ S ２ ), diammonium sulfide ((NH ４ ) 2S), dimethyl sulfide ((CH ３ ) ２ The selenide gas may be, for example, cerane (H ２ Se), diserane (H ２ Se ２ ), dimethylselenium ((CH ３ ) ２ The telluride gas may be, for example, one or more gases containing tellurium (H ２ Te), diterane (H ２ Te ２ ), dimethylselenium ((CH ３ ) ２ One or more of the gases containing Te and the like can be used.

[0051] (Removal of Residual Gas, Step S16) After the start of the supply of the reactive gas, for example, 0.01 to 60 seconds later, the valve 334 is closed to stop the supply of the reactive gas. Then, gas is removed from the space where the wafer 200 is present by a processing procedure similar to that of step S14 described above.

[0052] (Performed a Predetermined Number of Times, Step S17) By performing the cycle of forming a layer on the wafer 200 by the above-described steps S11 to S16 a predetermined number of times (n times, where n is an integer of 1 or 2 or greater), a film of a predetermined thickness is formed on the wafer 200. As the film, for example, a TiN film, which is a film mainly composed of titanium nitride (TiN), is formed. Here, a tungsten (W) film, for example, is used for the control gate of a NAND flash memory, and a TiN film may be formed as a barrier film between the W film and the insulating film. This TiN film serves to increase the adhesion between the W film and the insulating film.

[0053] Generally, the higher the temperature during film formation, the more likely it is that the proportion of crystal grains oriented in a predetermined crystal plane will increase relative to all crystal grains in the film. For example, the higher the temperature during TiN film formation, the higher the proportion of crystal grains oriented in a predetermined crystal plane (e.g., in the case of a TiN film, the {111} plane in the TiN crystal lattice). Here, "a high proportion of crystal grains oriented in a predetermined crystal plane (e.g., the {111} plane)" can also be interpreted as "high orientation to the predetermined crystal plane." Furthermore, "crystal grains oriented in a predetermined crystal plane" refers to "crystal grains that grow with the predetermined crystal plane facing in a direction perpendicular to the surface of the wafer 200."

[0054] Here, consider an example in which a TiN layer and a TiN film are formed on a wafer 200 using a source gas containing Ti as a predetermined element and Cl as a halogen element, and a reaction gas that is a nitriding gas. In such a case, Ti-Cl bonds in the molecular structure of the source gas, or N-Cl bonds formed when by-products such as halides (e.g., HCl) are adsorbed onto the layer, may remain in the TiN layer. FIG. 4A is an illustration of the formation of a TiN film (or TiN layer) on a wafer 200 under conditions that increase the amount of Cl contained in the TiN layer. FIG. 4B is an illustration of the formation of a TiN film (or TiN layer) on a wafer 200 under conditions that decrease the amount of Cl contained in the TiN layer.

[0055] As shown in Figure 4(B), when the amount of halogen elements contained in the TiN layer is small, the number of TiN crystal grains with disordered atomic arrangements is reduced. This makes it easier for the TiN crystal grains to align, which tends to increase the {111} plane orientation. TiN films with a high {111} plane orientation tend to form gaps between the TiN crystal grains. Therefore, oxygen and moisture in the atmosphere, as well as various processing solutions and gases used in other processes, can penetrate these gaps, potentially leading to oxidation of the TiN film and deterioration of its quality.

[0056] In contrast, as shown in Figure 4A, when the amount of halogen atoms contained in the TiN layer is large, the number of TiN crystal grains with disordered atomic arrangement increases. As a result, the proportion of crystal grains oriented in a direction other than the specified crystal plane increases, and the orientation of the {111} plane decreases. As a result, substances that can lead to oxidation of the TiN film or deterioration of film quality are less likely to penetrate between the TiN crystal grains, improving film quality.

[0057] That is, the relationship holds that the orientation of the predetermined crystal plane in the film decreases as the amount of halogen element contained in the layer increases. In other words, it can be said that there is a predetermined relationship between the amount of halogen element contained in the layer and the proportion of crystal grains in the film that are oriented in the predetermined crystal plane (the orientation of the predetermined crystal plane in the film). Furthermore, it can be said that the orientation of the predetermined crystal plane in the film (or layer) can be controlled by performing the above cycle under conditions for forming the layer (hereinafter referred to as "forming conditions") that are set based on the predetermined relationship.

[0058] Next, an example of setting forming conditions to control the amount of halogen element contained in the layer will be described. Also, an example of setting forming conditions to increase the amount of halogen element contained in the layer compared to when a film is formed using forming conditions different from the above-mentioned substrate processing process (hereinafter referred to as "conventional conditions") will also be described.

[0059] For example, the cycle is performed by controlling at least one of the exposure amount of the source gas, the exposure amount of the reducing gas, and the exposure amount of the reactive gas during the cycle, thereby controlling the amount of halogen element contained in the layer.

[0060] Specifically, the amount of halogen element contained in the layer can be increased by increasing the amount of exposure to the source gas compared to conventional conditions. Also, the amount of exposure to the source gas can be increased compared to conventional conditions by at least one of lengthening the supply time of the source gas in step S11 and / or S12, increasing the partial pressure of the source gas, increasing the process pressure during the supply of the source gas, increasing the molar fraction of the source gas, increasing the supply flow rate of the source gas, or decreasing the flow rate of the inert gas supplied simultaneously with the source gas.

[0061] Here, the "exposure amount of source gas" is calculated as, for example, "a value obtained by integrating the partial pressure of the source gas in the space where the wafer 200 is present during the process of supplying the source gas over the time from the start to the end of the supply of the source gas (hereinafter referred to as the "supply time of the source gas"). Also, the "partial pressure of the source gas" is calculated as, for example, "a value obtained by integrating the product of the molar fraction of the source gas and the process pressure in the space where the wafer 200 is present over time." The same applies to other gases.

[0062] Furthermore, by reducing the exposure amount of the reducing gas compared to conventional conditions, the amount of halogen element contained in the layer can be increased compared to conventional conditions. Furthermore, the exposure amount of the reducing gas can be reduced compared to conventional conditions by at least one of shortening the supply time of the reducing gas in step S12 and / or S13, lowering the partial pressure of the reducing gas, lowering the process pressure during the supply of the reducing gas, lowering the molar fraction of the reducing gas, lowering the supply flow rate of the reducing gas, or lowering the supply flow rate of the inert gas supplied simultaneously with the source gas.

[0063] In addition, by reducing the exposure amount of the reactive gas compared to the conventional conditions, the amount of halogen element contained in the layer can be increased compared to the conventional conditions. In addition, by controlling at least one of the following in step S15, the exposure amount of the reactive gas can be reduced compared to the conventional conditions: shortening the supply time of the reactive gas, lowering the partial pressure of the reactive gas, lowering the process pressure when supplying the reactive gas, reducing the mole fraction of the reactive gas, reducing the supply flow rate of the reactive gas, or increasing the flow rate of the inert gas supplied simultaneously with the reactive gas.

[0064] Furthermore, the above cycle may be performed by controlling the length of step S12, i.e., the length of the period during which the source gas and the reducing gas are simultaneously supplied (hereinafter referred to as the simultaneous supply time). This allows the amount of halogen element contained in the layer to be controlled. For example, by shortening the simultaneous supply time of the source gas and the reducing gas compared to the conventional conditions, the amount of halogen element contained in the layer can be increased compared to the conventional conditions.

[0065] Furthermore, the above cycle may be performed by controlling the conditions for residual gas removal in one or both of the above-described steps S14 and S16. This allows the amount of halogen elements contained in the layer to be controlled. Specifically, at least one of the residual gas removal time, the processing pressure during residual gas removal, and the supply flow rate of the purge gas during residual gas removal may be controlled as the residual gas removal condition. This allows the amount of halogen elements contained in the layer to be controlled.

[0066] Specifically, by shortening the time for residual gas removal compared to conventional conditions, the amount of halogen element contained in the layer can be increased compared to conventional conditions. Furthermore, by increasing the processing pressure during residual gas removal compared to conventional conditions, the amount of halogen element contained in the layer can be increased compared to conventional conditions. Furthermore, by decreasing the supply flow rate of purge gas during residual gas removal compared to conventional conditions, the amount of halogen element contained in the layer can be increased compared to conventional conditions.

[0067] For example, the orientation of the film can be evaluated by X-ray diffraction (XRD) measurement, which compares the intensity of X-ray diffraction from a predetermined crystal plane with the intensity of X-ray diffraction from one or more other crystal planes. Note that the orientation of the film may also be evaluated by a method other than X-ray diffraction.

[0068] For example, the orientation of two or more films formed under two or more conditions in which the amount of halogen contained in the layer is different from each other may be evaluated, thereby deriving a predetermined relationship between the amount of halogen contained in the layer and the orientation of a predetermined crystal plane in the film.

[0069] When forming a TiN film, if the processing temperature is less than 300°C, the reactivity of the processing gas (source gas, reactive gas, reducing gas) is low, making it difficult to form the layer. If the processing temperature is higher than 600°C, thermal decomposition of the processing gas is likely to proceed, making it difficult to form a TiN film with a uniform thickness in the recesses (trench or hole) formed on the wafer 200. Therefore, by setting the processing temperature to 300 to 600°C, it is possible to facilitate the formation of the TiN layer while also making it easier to form a TiN film with a uniform thickness.

[0070] Furthermore, by setting the processing temperature to 400°C or higher, the reactivity of the processing gas is further increased, thereby improving the electrical properties of the TiN film. When the processing temperature is 560°C or lower, the thermal decomposition of the processing gas is further inhibited, making it easier to form a TiN film with a uniform thickness in the recess. Therefore, when forming a TiN film, it is preferable to set the processing temperature to 400 to 560°C.

[0071] Furthermore, by setting the processing temperature to 450°C or higher, the reactivity of the processing gas is further increased, thereby further improving the electrical properties of the TiN film. In addition, when the processing temperature is set to 450°C or higher, the orientation of the {111} plane of the TiN film is increased, which makes it more likely that the film quality will deteriorate. Even in such cases, the technology disclosed herein can be used to reduce the orientation of the {111} plane of the TiN film. When the processing temperature is set to 530°C or lower, the thermal decomposition of the processing gas is further inhibited, making it easier to form a TiN film with a uniform thickness in the recess. Therefore, when forming a TiN film, it is more preferable to set the processing temperature to 450 to 530°C.

[0072] (After-purging and returning to atmospheric pressure) An inert gas is supplied into the processing chamber 201 from each of the gas supply pipes 510, 520, and 530, and is exhausted from the exhaust pipe 231. Thereafter, the atmosphere in the processing chamber 201 is replaced with the inert gas, and the pressure in the processing chamber 201 is returned to atmospheric pressure.

[0073] (Wafer Unloading) The boat elevator 115 lowers the seal cap 219, and the wafers 200 supported by the boat 217 are unloaded to the outside of the processing chamber 201. Thereafter, the wafers 200 are removed from the boat 217.

[0074] In the above-described substrate processing process, step S12 (simultaneous supply of source gas and reducing gas) and step S13 (supply of reducing gas) may be omitted. Specifically, as shown in FIG. 7, a cycle of forming a layer on wafer 200 by steps S11 and S14 to S16 may be repeated a predetermined number of times. Even in this case, at least some of the above-described effects can be obtained.

[0075] (3) Modifications The substrate processing step in this embodiment is not limited to the embodiment shown in FIG. 3, and can be modified as shown in the following modifications.

[0076] 5, this modification differs from the substrate processing step described above only in that the supply of a reducing gas is started simultaneously with the end of the supply of a source gas. The substrate processing step of this modification can also be expressed as follows.

[0077] (raw material gas → reducing gas → gas removal → reaction gas → gas removal) x n ⇒ predetermined film

[0078] In this modification, the amount of halogen element contained in the layer can be controlled, and the same effect as in the above-described embodiment can be obtained. Furthermore, in this modification, the processing time can be further shortened compared to the above-described embodiment, thereby improving throughput. The same effect can also be obtained when gas removal is performed between the end of the supply of the source gas and the start of the supply of the reducing gas.

[0079] 7, a first layer is formed under conditions that increase the amount of halogen element contained in the layer, and then a second layer is formed under conditions that decrease the amount of halogen element contained in the layer, thereby performing a process of forming a film on wafer 200. In other words, in the formation of the film, the formation conditions are changed at least once to change the amount of halogen element contained in the layer.

[0080] Specifically, as shown in Fig. 6, a first layer is formed by performing a cycle (hereinafter referred to as the "first cycle") including source gas supply, residual gas removal, reactive gas supply, and residual gas removal a predetermined number of times (m times, where m is an integer of 1 or greater), followed by the substrate processing step (hereinafter referred to as the "second cycle") shown in Fig. 3. Note that even with a sequence such as the first cycle, at least some of the above-described effects can be obtained.

[0081] Here, since the first cycle does not include the reducing gas supply step in the second cycle, the amount of halogen element contained in the first layer is greater than that in the second layer. That is, in this modification, a first layer containing a high halogen element content is formed on wafer 200, and then a second layer containing a low halogen element content is formed to form a predetermined film. The substrate processing process of this modification can also be expressed as follows.

[0082] (raw material gas → gas removal → reaction gas → gas removal) × m → (raw material gas → raw material gas + reducing gas → reducing gas → gas removal → reaction gas → gas removal) × n → predetermined film (second layer / first layer)

[0083] In this modified example, the processing procedures and processing conditions for forming the first layer can be the same as, for example, the source gas supply, gas removal, reactive gas supply, and gas removal in the substrate processing step shown in FIG.

[0084] In this modification, the first layer contains more halogen elements than the second layer, resulting in a lower proportion of crystal grains oriented in the predetermined crystal plane. Furthermore, because at least a portion of the second layer contains crystal grains from the first layer, the orientation of the second layer is likely to be similar to that of the first layer. Therefore, even though the second cycle is performed under conditions that result in a lower halogen content in the layer compared to the first cycle, a film with a lower orientation in the predetermined crystal plane can be formed. In other words, this modification reduces the amount of halogen elements contained in the entire film, thereby improving the electrical properties of the film. Furthermore, in the second cycle, the amount of halogen elements in the layer, which inhibits the adsorption of source gases and reactant gases, is reduced. This improves the film formation rate during the second cycle and the entire film formation.

[0085] The second cycle may be the cycle shown in Fig. 6. The first cycle may be the cycle shown in Fig. 3. In these cases, by making at least one of the formation conditions in the first and second cycles different from each other, the amounts of halogen elements contained in the first and second layers can be made different. The substrate processing steps of these modified examples can also be expressed as follows:

[0086] (raw material gas → gas removal → reaction gas → gas removal) × m → (raw material gas → gas removal → reaction gas → gas removal) × n ⇒ predetermined film (second layer / first layer)

[0087] (raw material gas → raw material gas + reducing gas → reducing gas → gas removal → reactive gas → gas removal) × m → (raw material gas → raw material gas + reducing gas → reducing gas → gas removal → reactive gas → gas removal) × n → predetermined film (second layer / first layer)

[0088] Alternatively, a predetermined film may be formed by forming a layer with a low halogen content on the wafer 200 and then forming a layer with a high halogen content. This modification also achieves at least some of the above-described effects. Furthermore, in forming the film, the formation conditions may be changed two or more times, or the formation conditions may be changed continuously for each cycle. Even in this case, at least some of the above-described effects can be achieved.

[0089] Furthermore, the orientation of the formed film may be controlled by at least one of the number of times m the first cycle is performed, the number of times n the second cycle is performed, the ratio n / m of n to m, and the ratio m / n of m to n. Even in such a case, at least some of the above-described effects can be obtained. Note that at least one of m, n, n / m, and m / n may be included in the above-described formation conditions.

[0090] For example, when m is increased and n is decreased (i.e., n / m is decreased and m / n is increased) compared to the conventional conditions, the amount of halogen element contained in the layer can be increased compared to the conventional conditions, and therefore, a film with a lower orientation of the predetermined crystal plane compared to the conventional conditions can be formed.

[0091] (Variation 3) In this variation, m, n, n / m, and m / n in the above-described variation 2 are changed at least once during film formation. The substrate processing flow in this variation is shown in FIG. 8. In this variation, a process of performing the first cycle m times and a process of performing the second cycle n times are performed. This forms a third layer on the wafer 200. Thereafter, a process of performing the first cycle m' times and a process of performing the second cycle n' times is performed to form a fourth layer on the third layer. Below, an example where m > m' and n < n' will be described. The substrate processing process in this variation can also be expressed as follows:

[0092] (raw material gas → gas removal → reactive gas → gas removal) × m → (raw material gas → raw material gas + reducing gas → reducing gas → gas removal → reactive gas → gas removal) × n → (raw material gas → gas removal → reactive gas → gas removal) × m' → (raw material gas → raw material gas + reducing gas → reducing gas → gas removal → reactive gas → gas removal) × n' ⇒ predetermined film (fourth layer / third layer)

[0093] In the process of forming the third layer, the number of first cycles is greater and the number of second cycles is less than in the process of forming the fourth layer. Therefore, the amount of halogen element contained in the third layer is greater than the amount of halogen element contained in the fourth layer. In other words, a predetermined film is formed by forming a third layer having a high halogen element content on the wafer 200 and then forming a fourth layer having a low halogen element content.

[0094] In this case, as described in Modification 2, at least a portion of the fourth layer contains crystal grains from the crystal-grown third layer, and the orientation of the fourth layer is likely to be similar to that of the third layer. Therefore, this modification can also achieve the same effects as Modification 2.

[0095] Note that the first cycle may not be performed in the formation of the third layer or the fourth layer, and the second cycle may not be performed in the formation of the third layer or the fourth layer. That is, one of m and m' may be 0, and one of n and n' may be 0.

[0096] (4) Other Aspects In the above aspects and modifications, a gas that does not contain the main constituent elements of the film is used as the reducing gas. However, the technology of the present disclosure is not limited to this. For example, a gas that contains the main constituent elements of the film and has a molecular structure different from that of the reactive gas may be used as the reducing gas. For example, when the reactive gas is a nitriding gas, a nitriding gas having a molecular structure different from that of the reactive gas may be used as the reducing gas.

[0097] In the above-described embodiments and modifications, an example of forming a film using a batch-type substrate processing apparatus that processes multiple wafers 200 at a time has been described. The present disclosure is not limited to the above-described embodiments and can be suitably applied, for example, to a case where a film is formed using a single-wafer substrate processing apparatus that processes one or several wafers 200 at a time. In the above-described embodiments, an example of forming a film using a substrate processing apparatus having a hot-wall processing furnace has been described. The present disclosure is not limited to the above-described embodiments and can be suitably applied to a case where a film is formed using a substrate processing apparatus having a cold-wall processing furnace.

[0098] When using these substrate processing apparatuses, each process can be performed using the same processing procedures and conditions as in the above-described embodiments and modifications, and the same effects as in the above-described embodiments and modifications can be obtained.

[0099] The above-described embodiments and modifications may be used in combination as appropriate. The processing procedures and processing conditions in such a case may be the same as those of the above-described embodiments and modifications, for example.

[0100] 200 wafers (substrates)

Claims

1. A substrate processing method having a step of forming a layer on the substrate by performing a cycle of supplying a raw material gas containing a halogen element to the substrate and a step of supplying a reaction gas to the substrate a predetermined number of times, and forming a film on the substrate, and performing the cycle under formation conditions set based on a predetermined relationship between the amount of the halogen element contained in the layer and the ratio occupied by crystal grains oriented on a predetermined crystal plane in the film.

2. The substrate processing method according to claim 1, wherein in the formation of the film, the formation conditions are changed at least once to change the amount of the halogen element contained in the layer.

3. The substrate processing method according to claim 2, wherein the amount of the halogen element contained in the layer formed after the change is made less than the amount of the halogen element contained in the layer formed before the change.

4. The cycle includes a first cycle and a second cycle, and the formation conditions of the second cycle are set such that the amount of the halogen element contained in the layer formed in the second cycle is different from the amount of the halogen element contained in the layer formed in the first cycle, and the ratio is controlled by at least one of the number of times m of performing the first cycle, the number of times n of performing the second cycle, the value n / m of the ratio of n to m, and the value m / n of the ratio of m to n. The substrate processing method according to claim 2.

5. The substrate processing method according to claim 4, wherein at least one of m, n, n / m, and m / n is changed at least once in the formation of the film.

6. The formation conditions include one or both of the exposure amount of the raw material gas in (a) and the exposure amount of the reaction gas in (b). The substrate processing method according to any one of claims 1 to 5.

7. The formation of the film further includes a step of supplying a reducing gas to the substrate. The substrate processing method according to any one of claims 1 to 5.

8. The reducing gas does not contain the main constituent element of the film. The substrate processing method according to claim 7.

9. (c) is performed at least partially simultaneously with (a). The substrate processing method according to claim 8.

10. The formation conditions include the length of the period during which (a) and (c) are performed simultaneously. The substrate processing method according to claim 9.

11. The substrate processing method according to claim 8, wherein (c) is started simultaneously with the end of (a).

12. The substrate processing method according to claim 7, wherein the formation conditions include at least one of the exposure amount of the source gas in (a), the exposure amount of the reaction gas in (b), and the exposure amount of the reducing gas in (c).

13. The film formation further includes a step of removing gas in the space where the substrate is present, and the formation conditions include the conditions for gas removal. The substrate processing method according to any one of claims 1 to 5.

14. The substrate processing method according to claim 13, wherein the conditions for gas removal include at least one of the time for performing gas removal, the pressure in the space during gas removal, and the supply flow rate of the purge gas during gas removal.

15. The substrate processing method according to claim 7, wherein the reducing gas contains the main constituent element of the film and has a molecular structure different from that of the reaction gas.

16. The substrate processing method according to any one of claims 1 to 5, wherein the film is a titanium nitride film.

17. The substrate processing method according to claim 16, wherein the predetermined crystal plane is the {111} plane in the crystal lattice of titanium nitride.

18. A method for manufacturing a semiconductor device, comprising performing a cycle of forming a layer on the substrate by supplying a source gas containing a halogen element to the substrate and supplying a reaction gas to the substrate a predetermined number of times, and forming a film on the substrate, and performing the cycle under formation conditions set based on a predetermined relationship between the amount of the halogen element contained in the layer and the ratio occupied by crystal particles oriented in a predetermined crystal plane in the film.

19. A program for causing a computer to execute a procedure for a substrate processing apparatus, the procedure including performing a cycle of forming a layer on the substrate by supplying a source gas containing a halogen element to the substrate and supplying a reaction gas to the substrate a predetermined number of times, and forming a film on the substrate, and performing the cycle under formation conditions set based on a predetermined relationship between the amount of the halogen element contained in the layer and the ratio occupied by crystal particles oriented in a predetermined crystal plane in the film.

20. A gas supply system for supplying a source gas containing a halogen element and a reaction gas to a substrate, and a process of forming a layer on the substrate by performing a cycle of forming a layer on the substrate by: (a) supplying the source gas to the substrate; and (b) supplying the reaction gas to the substrate a predetermined number of times, and having a process of forming a film on the substrate, and a process of performing the cycle under formation conditions set based on a predetermined relationship between the amount of the halogen element contained in the layer and the ratio occupied by crystal particles oriented on a predetermined crystal plane in the film, and a control unit configured to be able to control the gas supply system so that the process is performed. A substrate processing apparatus having the control unit.

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