JP7159446B2 - SUBSTRATE PROCESSING METHOD, SUBSTRATE PROCESSING APPARATUS, PROGRAM AND SEMICONDUCTOR DEVICE MANUFACTURING METHOD - Google Patents

Description

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

2. Description of the Related Art In recent years, as semiconductor devices have become more highly integrated and have higher performance, various types of metal films have been used to manufacture semiconductor devices having a three-dimensional structure (see, for example, Patent Documents 1 and 2).

JP 2017-69407 A JP 2018-49898 A

A tungsten film (W film) or the like is used for a control gate of a NAND flash memory, which is an example of a semiconductor device having a three-dimensional structure. The resistance of this W film has a great influence on device characteristics, and a film with low resistance is required.

According to one aspect of the present disclosure,
housing the substrate in a processing chamber;
a first film forming step of supplying a first process gas containing a first element to the substrate to form a film containing the first element on the substrate;
A second process gas containing a second element is supplied to the film containing the first element to remove the first element from the film containing the first element and reform the film containing the second element. a second film forming step;
is provided.

According to the present disclosure, it is possible to form a low resistance film.

1 is a longitudinal sectional view showing an outline of a vertical processing furnace of a substrate processing apparatus; FIG. FIG. 3 is a schematic cross-sectional view taken along line AA in FIG. 2; FIG. 2 is a schematic configuration diagram of a controller of the substrate processing apparatus, showing a control system of the controller in a block diagram; FIG. It is a flowchart which shows operation|movement of a substrate processing apparatus. It is a flow figure which shows the operation|movement of a 1st film-forming process. FIG. 4 is a diagram showing the timing of gas supply in the first film formation process; It is a flowchart which shows the operation|movement of a 2nd film-forming process. It is a figure which shows the timing of gas supply in a 3rd film-forming process. It is a figure which shows the effect of this technique.

<Embodiment>
An example of an embodiment will be described below with reference to the drawings.

(1) Configuration of substrate processing apparatus
The substrate processing apparatus 10 includes a processing furnace 202 provided with a heater 207 as heating means (heating mechanism, heating system). The heater 207 has a cylindrical shape and is vertically installed by being supported by a heater base (not shown) as a holding plate.

Inside the heater 207 , an outer tube 203 forming a reaction vessel (processing vessel) is arranged concentrically with the heater 207 . The outer tube 203 is made of a heat-resistant material such as quartz (SiO ₂ ) or silicon carbide (SiC). The shape of the outer tube 203 is a cylindrical shape with a closed upper end and an open lower end. A manifold (inlet flange) 209 is arranged concentrically with the outer tube 203 below the outer tube 203 . The manifold 209 is made of a metal material such as stainless steel (SUS). The shape of the manifold 209 is formed in a cylindrical shape with an upper end and a lower end opened. An O-ring 220a is provided between the upper end of the manifold 209 and the outer tube 203 as a sealing member. By supporting the manifold 209 on the heater base, the outer tube 203 is vertically installed.

An inner tube 204 forming a reaction container is arranged inside the outer tube 203 . The inner tube 204 is made of a heat-resistant material such as quartz or SiC. The shape of the inner tube 204 is a cylindrical shape with a closed upper end and an open lower end. A processing vessel (reaction vessel) is mainly composed of the outer tube 203 , the inner tube 204 and the manifold 209 . A processing chamber 201 is formed in the cylindrical hollow portion of the processing container (inside the inner tube 204).

The processing chamber 201 is configured so that the wafers 200 as substrates can be accommodated in a state in which the wafers 200 are horizontally arranged in the vertical direction in multiple stages by a boat 217 which will be described later.

Nozzles 410 , 420 , 430 are provided in the processing chamber 201 so as to penetrate the sidewall of the manifold 209 and the inner tube 204 . Gas supply pipes 310, 320 and 330 are connected to the nozzles 410, 420 and 430, respectively. However, the processing furnace 202 of this embodiment is not limited to the form described above.

Mass flow controllers (MFC) 312, 321, and 332, which are flow rate controllers (flow control units), are provided in the gas supply pipes 310, 320, and 330, respectively, in this order from the upstream side. Valves 314, 324, and 334, which are open/close valves, are provided in the gas supply pipes 310, 320, and 330, respectively. Gas supply pipes 510, 520, 530 for supplying inert gas are connected to the downstream sides of the valves 314, 324, 334 of the gas supply pipes 310, 320, 330, respectively. Gas supply pipes 510, 520, 530 are provided with MFCs 512, 522, 532 and valves 514, 524, 534, respectively, in this order from the upstream side.

Also, the gas supply pipe 310 may be connected to a gas supply pipe 310-2. The gas supply pipe 310-2 is provided with an MFC 312-2 and a valve 314-2 from the upstream side.

Nozzles 410, 420 and 430 are connected to the distal ends of the gas supply pipes 310, 320 and 330, respectively. The nozzles 410 , 420 , 430 are configured as L-shaped nozzles, and their horizontal portions are provided so as to penetrate the side wall of the manifold 209 and the inner tube 204 . The vertical portions of the nozzles 410, 420, and 430 project outward in the radial direction of the inner tube 204 and extend vertically in a channel-shaped (groove-shaped) preliminary chamber 201a. , and is provided along the inner wall of the inner tube 204 in the preliminary chamber 201a upward (upward in the direction in which the wafers 200 are arranged).

The nozzles 410 , 420 , 430 are provided to extend from the lower region of the processing chamber 201 to the upper region of the processing chamber 201 , and have a plurality of gas supply holes 410 a , 420 a , 430 a at positions facing the wafer 200 . is provided. Thereby, the processing gas is supplied to the wafer 200 from the gas supply holes 410a, 420a, 430a of the nozzles 410, 420, 430, respectively. A plurality of gas supply holes 410a, 420a, 430a are provided from the lower portion to the upper portion of the inner tube 204, each having the same opening area and the same opening pitch. However, the gas supply holes 410a, 420a, and 430a are not limited to the forms described above. For example, the opening area may gradually increase from the bottom to the top of the inner tube 204 . This makes it possible to make the flow rate of the gas supplied from the gas supply holes 410a, 420a, and 430a more uniform.

A plurality of gas supply holes 410a, 420a, 430a of the nozzles 410, 420, 430 are provided at a height from the bottom to the top of the boat 217, which will be described later. Therefore, the processing gas supplied into the processing chamber 201 through the gas supply holes 410a, 420a, 430a of the nozzles 410, 420, 430 is supplied to the entire area of the wafers 200 accommodated from the bottom to the top of the boat 217. FIG. The nozzles 410 , 420 , 430 may be provided so as to extend from the lower region to the upper region of the processing chamber 201 , but are preferably provided so as to extend to the vicinity of the ceiling of the boat 217 .

A flash tank 322 is arranged between the MFC 321 and the valve 324 in the gas supply pipe 320 .

A gas containing silicon (Si) element is supplied as a first processing gas from the gas supply pipe 310 into the processing chamber 201 via the MFC 311 , the valve 314 and the nozzle 410 . A silane-based gas can be used as the first processing gas. A silane-based gas is a gas that contains silicon (Si) and hydrogen (H) and does not contain halogen. Specifically, monosilane (SiH ₄ ) gas can be used. SiH ₄ acts as a deposition gas to form the first film. In addition, as such a first processing gas, there is, for example, disilane (Si ₂ H ₆ ).

Further, when the gas supply pipe 310-2 is provided, a processing gas containing silicon (Si) element and different from the first processing gas (also referred to as a first second processing gas) is supplied from the gas supply pipe 310-2. is supplied into the processing chamber 201 through the MFC 312 - 2 , the valve 314 - 2 and the nozzle 420 . The processing gas different from the first processing gas is, for example, a gas containing silicon (Si) and hydrogen and containing halogen. Specifically, when the first process gas is _SiH4 gas, the process gas different from the first process gas is hexachlorodisilane (HCDS) gas.

A source gas containing a metal element (metal-containing gas) is supplied as a second processing gas from the gas supply pipe 320 into the processing chamber 201 via the MFC 322 , the valve 324 and the nozzle 420 . As the second processing gas, for example, tungsten (W) is included as a metal element, and tungsten hexafluoride (WF ₆ ) is used as a halogen-based raw material (halide, halogen-based tungsten raw material).

From the gas supply pipe 330 , a reaction gas is supplied as a third processing gas into the processing chamber 201 via the MFC 332 , the valve 334 and the nozzle 430 . As the reaction gas, for example, hydrogen (H ₂ ) gas, which is an H-containing gas containing hydrogen (H), can be used.

From gas supply pipes 510, 520, 530, inert gas such as nitrogen (N ₂ ) gas is supplied to the processing chamber through MFCs 512, 522, 532, valves 514, 524, 534, and nozzles 410, 420, 430, respectively. 201. An example using _N2 gas as the inert gas will be described below. Examples of the inert gas other than _N2 gas include argon (Ar) gas, helium (He) gas, neon (Ne) gas, and xenon. A rare gas such as (Xe) gas may be used.

A gas supply unit is mainly composed of gas supply pipes 310, 320, 330, MFCs 311, 322, 332, valves 314, 324, 334, and nozzles 410, 420, 430. You can think of it as a supply unit. When the first processing gas is supplied from the gas supply pipe 310, the gas supply pipe 310, the MFC 311, and the valve 314 mainly constitute the first processing gas supply unit, but only the nozzle 410 is considered as the first processing gas supply unit. may When the second processing gas is supplied from the gas supply pipe 320, the gas supply pipe 320, the MFC 322, and the valve 324 mainly constitute the second processing gas supply section. You can consider including it in Also, the flash tank 322 may be included in the second processing gas supply section. When the reaction gas is supplied from the gas supply pipe 330, the gas supply pipe 330, the MFC 332, and the valve 334 mainly constitute a third processing gas supply section (reaction gas supply section). It may be considered to be included in the processing gas supply unit. When a nitrogen-containing gas is supplied as the reaction gas from the gas supply pipe 330, the reaction gas supply section can also be referred to as a nitrogen-containing gas supply section. In addition, the gas supply pipes 510, 520, 530, the MFCs 512, 522, 532, and the valves 514, 524, 534 mainly constitute an inert gas supply section.

The method of gas supply in this embodiment includes nozzles 410 , 420 , 420 , 420 , 420 , 420 , 420 , 420 , 420 , 420 , 420 , 420 , 420 , 420 , 420 , 420 , 420 , 420 , 420 , 420 , 420 , 420 , 420 , 420 , 420 , 420 , 420 , 420 , 420 , 420 . 430 to convey gas. Gas is jetted into the inner tube 204 from a plurality of gas supply holes 410a, 420a, 430a provided at positions of the nozzles 410, 420, 430 facing the wafer. More specifically, gas or the like is ejected in a direction parallel to the surface of the wafer 200 from the gas supply hole 410a of the nozzle 410, the gas supply hole 420a of the nozzle 420, and the gas supply hole 430a of the nozzle 430. FIG.

The exhaust hole (exhaust port) 204a is a through hole formed in a side wall of the inner tube 204 at a position facing the nozzles 410, 420, and 430. For example, the exhaust hole (exhaust port) 204a is a slit-like through hole elongated in the vertical direction. is. The gas supplied into the processing chamber 201 from the gas supply holes 410a, 420a, and 430a of the nozzles 410, 420, and 430 and flowed over the surface of the wafer 200 passes through the exhaust hole 204a and flows between the inner tube 204 and the outer tube 203. It flows into the exhaust passage 206 formed by the gap formed therebetween. Then, the gas that has flowed into the exhaust path 206 flows into the exhaust pipe 231 and is discharged out of the processing furnace 202 .

The exhaust holes 204a are provided at positions facing the side surfaces of the plurality of wafers 200, and the gas supplied to the vicinity of the wafers 200 in the processing chamber 201 from the gas supply holes 410a, 420a, and 430a flows horizontally. , and then flows into the exhaust path 206 via the exhaust hole 204a. The exhaust hole 204a is not limited to being configured as a slit-shaped through hole, and may be configured by a plurality of holes.

The manifold 209 is provided with an exhaust pipe 231 for exhausting the atmosphere inside the processing chamber 201 . The exhaust pipe 231 includes, in order from the upstream side, a pressure sensor 245 as a pressure detector (pressure detection unit) for detecting the pressure in the processing chamber 201, an APC (Auto Pressure Controller) valve 243, and a vacuum pump as an evacuation device. 246 are connected. The APC valve 243 can evacuate the processing chamber 201 and stop the evacuation by opening and closing the valve while the vacuum pump 246 is in operation. By adjusting the opening degree, the pressure in the processing chamber 201 can be adjusted by adjusting the exhaust conductance. An exhaust portion is mainly composed of the exhaust hole 204 a , the exhaust path 206 , the exhaust pipe 231 , the APC valve 243 and the pressure sensor 245 . At least the exhaust port 204a may be considered as an exhaust portion. A vacuum pump 246 may be considered to be included in the exhaust section.

Below the manifold 209, a seal cap 219 is provided as a furnace mouth cover capable of hermetically closing the lower end opening of the manifold 209. As shown in FIG. The seal cap 219 is configured to contact the lower end of the manifold 209 from below in the vertical direction. The seal cap 219 is made of a metal material such as SUS. The shape of the seal cap 219 is formed in a disc shape. An O-ring 220 b is provided on the upper surface of the seal cap 219 as a sealing member that contacts the lower end of the manifold 209 . A rotating mechanism 267 for rotating the boat 217 containing the wafers 200 is installed on the side of the seal cap 219 opposite to the processing chamber 201 . A rotating shaft 255 of the rotating mechanism 267 passes through the seal cap 219 and is connected to the boat 217 . The rotating mechanism 267 is configured to rotate the wafers 200 by rotating the boat 217 . The seal cap 219 is configured to be vertically moved up and down by a boat elevator 115 as a lifting mechanism installed vertically outside the outer tube 203 . The boat elevator 115 is configured to move the boat 217 into and out of the processing chamber 201 by raising and lowering the seal cap 219 . The boat elevator 115 is configured as a transport device (transport mechanism) that transports the boat 217 and the wafers 200 housed in the boat 217 into and out of the processing chamber 201 .

The boat 217 as a substrate support is configured so that a plurality of wafers 200, for example, 1 to 200 wafers 200, can be arranged in a horizontal posture with their centers aligned with each other at intervals in the vertical direction. there is The boat 217 is made of a heat-resistant material such as quartz or SiC. At the bottom of the boat 217, heat-insulating plates 218 made of a heat-resistant material such as quartz or SiC are supported horizontally in multiple stages (not shown). This configuration makes it difficult for heat from the heater 207 to be transmitted to the seal cap 219 side. However, this embodiment is not limited to the form described above. For example, instead of providing the heat insulating plate 218 at the bottom of the boat 217, a heat insulating cylinder configured as a cylindrical member made of a heat-resistant material such as quartz or SiC may be provided.

As shown in FIG. 2, a temperature sensor 263 as a temperature detector is installed in the inner tube 204. By adjusting the amount of electricity supplied to the heater 207 based on the temperature information detected by the temperature sensor 263, The temperature inside the processing chamber 201 is configured to have a desired temperature distribution. Temperature sensor 263 is L-shaped, similar to nozzles 410 , 420 and 430 , and is provided along the inner wall of inner tube 204 .

As shown in FIG. 3, a controller 121, which is a control unit (control means), is configured as a computer having a CPU (Central Processing Unit) 121a, a RAM (Random Access Memory) 121b, a storage device 121c, and an I/O port 121d. It is The RAM 121b, storage device 121c, and 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 configured as, for example, a touch panel or the like is connected to the controller 121 .

The storage device 121c is composed of, for example, a flash memory, a HDD (Hard Disk Drive), or the like. In the storage device 121c, a control program for controlling the operation of the substrate processing apparatus, a process recipe describing the procedure and conditions of a method for manufacturing a semiconductor device, which will be described later, and the like are stored in a readable manner. The process recipe functions as a program in which the controller 121 executes each process (each step) in the method of manufacturing a semiconductor device to be described later and is combined so as to obtain a predetermined result. Hereinafter, this process recipe, control program, etc. will be collectively referred to simply as a program. When the term program is used in this disclosure, it may include only a process recipe alone, may include only a control program alone, or may include a combination of a process recipe and a control program. The RAM 121b is configured as a memory area (work area) in which programs and data read by the CPU 121a are temporarily held.

The I/O port 121d includes the above-mentioned MFCs 312, 321, 332, 512, 522, 532, 312-2, valves 314, 324, 334, 514, 524, 534, 314-2, pressure sensor 245, APC valve 243, The vacuum pump 246, heater 207, temperature sensor 263, rotating mechanism 267, boat elevator 115, etc. are connected so as to be controllable. Here, the term "connection" includes direct electrical connection, indirect connection, and direct or indirect transmission and reception of electrical signals.

The CPU 121a is configured to read out and execute a control program from the storage device 121c, and to read recipes and the like from the storage device 121c in response to input of operation commands from the input/output device 122 and the like. The CPU 121a adjusts the flow rate of various gases by the MFCs 312, 321, 332, 512, 522, 532, and 312-2, valves 314, 324, 334, 514, 524, 534, and 314 so as to follow the content of the read recipe. -2 opening/closing operation, opening/closing operation of the APC valve 243, pressure adjustment operation based on the pressure sensor 245 by the APC valve 243, temperature adjustment operation of the heater 207 based on the temperature sensor 263, starting and stopping of the vacuum pump 246, rotation mechanism 267 It is configured to control the rotation of the boat 217 and the rotation speed adjustment operation, the lifting operation of the boat 217 by the boat elevator 115, the storage operation of the wafers 200 in the boat 217, and the like.

The controller 121 is stored in an external storage device 123 (for example, a magnetic tape, a magnetic disk such as a flexible disk or a hard disk, an optical disk such as a CD or DVD, a magneto-optical disk such as an MO, or a semiconductor memory such as a USB memory or a memory card). The program described above can be configured by installing it in a computer. The storage device 121c and the external storage device 123 are configured as computer-readable recording media. Hereinafter, these are also collectively referred to simply as recording media. In the present disclosure, the recording medium may include only the storage device 121c alone, may include only the external storage device 123 alone, or may include both. The program may be provided to the computer without using the external storage device 123, but using communication means such as the Internet or a dedicated line.

(2) Substrate processing step (film formation step)
FIG. 4 shows an example of a process of forming a metal film constituting, for example, a control gate film of a flash memory or a word line electrode of a MOSFET on a wafer 200 as one process of manufacturing a semiconductor device (device). explain. The step of forming the metal film is performed using the processing furnace 202 of the substrate processing apparatus 10 described above. In the following description, the controller 121 controls the operation of each component of the substrate processing apparatus 10 .

On the surface of the wafer 200, there is a titanium nitride TiN film as a barrier metal that suppresses the diffusion of fluorine (F) in the _WF6 gas, which will be described later, into an insulating film (not shown) formed on the wafer 200. formed. When forming a tungsten (W) film as a word line electrode on such a barrier metal, there is a problem that the resistivity of the W film increases, and it is required to lower the resistivity of the W film.

When the word "wafer" is used in the present disclosure, "wafer itself", "laminate of wafer and predetermined layer or film formed on its surface", "wafer and structure formed on its surface It can mean "body". In the present disclosure, when the term "wafer surface" is used, it means "the surface of the wafer itself", "the surface of a predetermined layer or film formed on the wafer", "the wafer and the structure formed on its surface It can mean "body". The use of the term "substrate" in this disclosure is synonymous with the use of the term "wafer."

The flow and gas supply sequence of the method for manufacturing a semiconductor device according to the present disclosure will be described below with reference to FIGS. 4 to 8. FIG. 6 and 8, the horizontal axis represents time, and the vertical axis represents ON/OFF of each gas.

[Substrate loading step S301]
When a plurality of wafers 200 are loaded into the boat 217 (wafer charge), the boat 217 supporting the plurality of wafers 200 is lifted by the boat elevator 115 to move to the processing chamber 201 as shown in FIG. It is carried in (boat load) inside. In this state, the seal cap 219 closes the opening of the lower end of the reaction tube 203 via the O-ring 220 .

[Atmosphere adjustment step S302]
The inside of the processing chamber 201 is evacuated by a vacuum pump 246 to a desired pressure (degree of vacuum). At this time, the pressure in 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 vacuum pump 246 is kept in operation at least until the processing of the wafer 200 is completed. Further, the inside of the processing chamber 201 is heated by the heater 207 so as to reach a desired temperature. At this time, the amount of power supplied to the heater 207 is feedback-controlled based on the temperature information detected by the temperature sensor 263 so that the inside of the processing chamber 201 has a desired temperature distribution (temperature adjustment). Heating in the processing chamber 201 by the heater 207 is continued at least until the processing of the wafer 200 is completed.

[Initial film formation step S300]
Subsequently, an initial film forming step S300 is performed. The initial film forming step S300 has at least a first film forming step S303 and a second film forming step S305 described below. Each step will be described with reference to FIGS. 5, 6, and 7. FIG.

[First film formation step S303]
The first film formation step S303 includes at least a first process gas supply step S303a, as indicated by solid lines in FIGS. 5 and 6, purge steps S303b and S303d, a processing gas supply step S303c different from the first processing gas, and a judgment step S303e may be included. Each step will be described below.

[First process gas supply step S303a]
In the first processing gas supply step S303a, SiH ₄ gas as a first processing gas is supplied to the wafers 200 in the processing chamber 201 .

( _SiH4 gas supply)
The valve 314 is opened to allow the SiH ₄ gas, which is the first processing gas, to flow through the gas supply pipe 310 . The SiH ₄ gas is flow-controlled by the MFC 312 , supplied into the processing chamber 201 through the gas supply hole 410 a of the nozzle 410 , and exhausted through the exhaust pipe 231 . At this time, the valve 514 is opened at the same time to flow an inert gas such as N ₂ gas into the gas supply pipe 510 . The N ₂ gas flowing through the gas supply pipe 510 is flow-controlled by the MFC 512 , supplied into the processing chamber 201 together with the SiH ₄ gas, and exhausted through the exhaust pipe 231 . At this time, in order to prevent the SiH ₄ gas from entering the nozzles 420 and 430 , the valves 524 and 534 are opened to allow the N ₂ gas to flow through the gas supply pipes 520 and 530 . N ₂ gas is supplied into the processing chamber 201 through gas supply pipes 320 and 330 and nozzles 420 and 430 and exhausted through an exhaust pipe 231 . At this time, SiH ₄ gas and N ₂ gas are simultaneously supplied to the wafer 200 .

At this time, the APC valve 243 is adjusted to set the pressure in the processing chamber 201 within a range of, for example, 1 to 3990 Pa, preferably 5 to 2660 Pa, more preferably 10 to 1500 Pa. The supply flow rate of the SiH ₄ gas controlled by the MFC 312 is, for example, 0.1 to 5 slm, preferably 0.3 to 3 slm, more preferably 0.5 to 2 slm. Specifically, it is set to 1.0 slm. The supply flow rates of the N ₂ gas controlled by the MFCs 512, 522 and 532 are, for example, within the range of 0.01 to 20 slm, preferably 0.1 to 10 slm, and more preferably 0.1 to 1 slm.

By supplying SiH ₄ gas, a silicon (Si) film is formed on the wafer 200 as a first film. The Si film is formed, for example, by two atomic layers or more, preferably 2 nm to 30 nm, more preferably about 5 nm.

The Si film as the first film may be vapor-phase grown by continuously supplying SiH ₄ gas, or by alternately supplying two Si-based gases. By alternately supplying the two Si-based gases, it is possible to improve the uniformity of the Si film formed on the surface of the structures formed on the wafer 200 . That is, it becomes possible to improve coverage characteristics. The flow of the process of alternately supplying the Si-based gas will be described with reference to FIGS. 5 and 6. FIG.

First, after the first processing gas supply step S303a, a processing gas supply step S303c different from the first processing gas is performed. Then, the purge step S303b may be performed.

[Purge step S303b]
In the purge step S303b, _N2 gas is supplied into the processing chamber 201 as an inert gas. N ₂ gas as an inert gas is supplied into the processing chamber 201 to adjust the pressure inside the processing chamber 201 . The flow rate of N ₂ gas is, for example, 0.1 to 5 slm, preferably 0.3 to 3 slm, more preferably 0.5 to 2 slm. The pressure at this time is adjusted so as to be the pressure when the first gas is supplied later. The pressure is set within a range of 1 to 3990 Pa, for example.

After supplying the _N2 gas for a predetermined time, the supply of the _N2 gas is stopped or the flow rate is reduced. The N ₂ gas may be supplied from all the nozzles existing in the processing chamber 201, or may be supplied from any one of them. Also, it may be configured to supply from a nozzle other than the nozzle used in the next step. Further, the supply of N ₂ gas is stopped or the flow rate is reduced, and this state is maintained for a predetermined time to remove unreacted SiH ₄ gas and by-products present in the processing chamber 201 .

[Processing gas different from the first processing gas (first two processing gases) supply step S303c]
In the process gas supply step S303a different from the first process gas, the wafers 200 in the process chamber 201 are supplied with the HCDS gas as a process gas different from the first process gas.

(HCDS gas supply)
The valve 314-2 is opened to flow the HCDS gas, which is a processing gas different from the first processing gas, into the gas supply pipe 310. FIG. The flow rate of the HCDS gas is adjusted by the MFC 312 - 2 , supplied into the processing chamber 201 through the gas supply hole 410 a of the nozzle 410 , and exhausted through the exhaust pipe 231 . At this time, the valve 514 is opened at the same time to flow an inert gas such as N ₂ gas into the gas supply pipe 510 . The N ₂ gas flowing through the gas supply pipe 510 is adjusted in flow rate by the MFC 512 , supplied into the processing chamber 201 together with the HCDS gas, and exhausted through the exhaust pipe 231 . At this time, in order to prevent the HCDS gas from entering the nozzles 420 and 430, the valves 524 and 534 are opened to allow the N ₂ gas to flow through the gas supply pipes 520 and 530. N ₂ gas is supplied into the processing chamber 201 through gas supply pipes 320 and 330 and nozzles 420 and 430 and exhausted through an exhaust pipe 231 . At this time, the HCDS gas and the N ₂ gas are simultaneously supplied to the wafer 200 .

At this time, the APC valve 243 is adjusted to set the pressure in the processing chamber 201 within a range of, for example, 1 to 3990 Pa, preferably 5 to 2660 Pa, more preferably 10 to 1500 Pa. The supply flow rate of the HCDS gas controlled by the MFC 312 is, for example, 0.1 to 5 slm, preferably 0.3 to 3 slm, more preferably 0.5 to 2 slm. Specifically, it is set to 1.0 slm. The supply flow rates of the N ₂ gas controlled by the MFCs 512, 522 and 532 are, for example, within the range of 0.01 to 20 slm, preferably 0.1 to 10 slm, and more preferably 0.1 to 1 slm. After a predetermined time has passed, the valve 314-2 is closed.

By supplying the HCDS gas, a silicon (Si) film is formed on the wafer 200 as a first film.

[Purge step S303d]
Subsequently, a purge step S303d is performed. Since the purge step S303d is substantially the same as the purge step S303b described above, the description thereof will be omitted. By performing the purge step S303d, unreacted HCDS gas and by-products (HCl) existing in the processing chamber 201 are removed.

[Determination step S303e]
Subsequently, a determination step S303e may be performed. In the determination step S303e, it is determined whether the first processing gas supply step S303a and the processing gas supply step S303c different from the first processing gas have been performed a predetermined number of times. If it has been performed the predetermined number of times, a YES (Y) determination is made, the first film forming step S303 is terminated, and the next step is performed. If it has not been performed a predetermined number of times, it is determined as No (N), and the first film forming step S303 is performed again.

A Si film is formed on the wafer 200 in the first film forming step S303.

Subsequently, a second film forming step S305 is performed. Note that the purge step S304 may be performed between the first film formation step S303 and the second film formation step S305.

[Purge step S304]
Since the purge step S304 is substantially the same as the purge steps S303b and S303d described above, the description thereof will be omitted. By performing the purge step here, the first processing gas in the processing chamber 201 or a processing gas different from the first processing gas is suppressed from reacting with the metal-containing gas supplied in the second film formation step S305. It becomes possible to For example, the HCDS gas and the WF6 gas are prevented from reacting to form tungsten silicide (WSi).

[Second film formation step S305]
The second film formation step S305 includes at least a second processing gas supply step S305a, as indicated by the solid line in FIG. As indicated by the dashed line in FIG. 7, the purge step S305b and determination step S305c may be included. Each step will be described below.

[Second process gas supply step S305a]
_In the second processing gas supply step S305a, the wafer 200 is supplied with WF6 gas as the second processing gas.

(WF ₆ gas supply)
The valve 324 is opened to allow the WF ₆ gas, which is the second processing gas, to flow through the gas supply pipe 320 . The WF ₆ gas is flow-controlled by the MFC 321 , supplied into the processing chamber 201 through the gas supply hole 420 a of the nozzle 420 , and exhausted through the exhaust pipe 231 . At this time, the valve 524 is opened at the same time to flow an inert gas such as N ₂ gas into the gas supply pipe 520 . The N ₂ gas flowing through the gas supply pipe 520 is adjusted in flow rate by the MFC 522 , supplied into the processing chamber 201 together with the WF ₆ gas, and exhausted through the exhaust pipe 231 . At this time, in order to prevent the _WF6 gas from entering the nozzles 410 and 430, the valves 514 and 534 are opened to allow the _N2 gas to flow through the gas supply pipes 510 and 530. N ₂ gas is supplied into the processing chamber 201 through gas supply pipes 310 and 330 and nozzles 410 and 430 and exhausted through an exhaust pipe 231 . At this time, _WF6 gas and _N2 gas are simultaneously supplied to the wafer 200 .

At this time, the APC valve 243 is adjusted to set the pressure in the processing chamber 201 within a range of, for example, 1 to 3990 Pa, preferably 5 to 2660 Pa, more preferably 10 to 1500 Pa. The supply flow rate of the WF ₆ gas controlled by the MFC 312 is, for example, 0.1 to 5 slm, preferably 0.3 to 3 slm, more preferably 0.5 to 2 slm. Specifically, it is set to 1.0 slm. The supply flow rates of the N ₂ gas controlled by the MFCs 512, 522 and 532 are, for example, within the range of 0.01 to 20 slm, preferably 0.1 to 10 slm, and more preferably 0.1 to 1 slm.

When the WF ₆ gas comes into contact with the silicon (Si) film as the first film formed on the wafer 200, the following reaction occurs. A reaction of 6Si+4WF ₆ →6SiF ₄ +4W occurs. This reaction converts (changes) the Si film as the first film formed on the wafer 200 into a tungsten (W) film as the second film. Si formed on the wafer 200 is desorbed (sublimated) as SiF ₄ . In the course of this reaction, W replaces Si sites on the wafer 200, and a W film is formed. Thereby, a W film is formed on the wafer 200 . A film in which W atoms (W crystals) are densely arranged is formed. Therefore, for example, a W film having a lower resistance than a W film formed by performing a third film forming step, which will be described later, is directly formed on the barrier metal.

Preferably, _WF6 gas is stored in the flash tank 322 in advance, and the WF6 gas is flash _- supplied. By flash _- supplying the WF6 gas, it is possible to improve the removal efficiency of by-products generated in the reaction while supplying the _WF6 gas.

Here, when the Si film of 5 nm is formed on the wafer 200, the supply of _WF6 gas is continued until the W film of about 3 nm is formed, and the Si film on the wafer 200 is changed to the W film. conversion. In order to remove impurities (Si and fluorine (F)) in the W film, the second process gas supply step S305a may be performed intermittently. In other words, as shown in FIG. 7, the second processing gas supply step S305a and the purge step S305b may be performed repeatedly.

[Purge step S305b]
The purge step S305b is substantially the same procedure as the above-described other purge steps, so description thereof will be omitted. By performing the purging step S305b, by-products present on the wafer 200 and in the processing chamber 201 are removed. This makes it possible to lower the impurity concentration in the W film as the second film. That is, it becomes possible to lower the resistivity of the W film.

[Determination step S305c]
In the determination step S305c, it is determined whether or not the second process gas supply step S305a has been performed for a predetermined time (predetermined number of times). If it has been performed the predetermined number of times, a YES (Y) determination is made, the second film forming step S305 is terminated, and the next step is performed. If it has not been performed a predetermined number of times, it is determined as No (N), and the second film forming step S303 is performed again.

In this manner, the second film forming step S305 is performed. After the second film formation step S305, the third film formation step S400 is performed. and

[Purge step S306]
The purge step S306 is substantially the same procedure as the above-described other purge steps, so description thereof is omitted. By performing the purge step S306, it becomes possible to lower the impurity concentration in the W film as the second film. That is, it becomes possible to lower the resistivity of the W film.

[Determination step S307]
In the determination step S307, when the first film formation step S303 and the second film formation step S305 are repeated, it is determined whether or not these two steps have been performed a predetermined number of times. If it has been performed the predetermined number of times, a YES (Y) determination is made, the initial film forming step S300 is terminated, and the next step is performed. If it has not been performed a predetermined number of times, it is determined as No (N), and the initial film forming step S300 is performed again.

[Main film forming step (third film forming step) S400]
After the initial film forming step S300, the main film forming step (third film forming step) S400 is performed. In the main film forming step S400, as indicated by the solid line in FIG. 4, at least a second processing gas supply step S403 and a third processing gas supply step S405 are performed. In order to improve the film characteristics of the main film formed on the wafer 200, the purging steps S404 and S406 and the determination step S407 indicated by broken lines in FIG. 4 may be performed. Each step will be described below.

[Second process gas supply step S403]
In the second processing gas supply step S403, substantially the same procedure as in the above-described second processing gas supply step S305a is performed on the wafer 200 on which the initial film having the W film as the second film is formed. Description is omitted. By performing the second processing gas supply step S403, a (WFx) film containing W and F is formed on the initial film having the W film as the second film. Here, x is a natural number smaller than 4. The crystals (W atoms) of the initial W film are densely arranged, and WFx is adsorbed along the initial crystals (W atoms) of the W film in the second process gas supply step S403.

[Purge step S404]
Next, a purge step S404 is performed. The purge step S404 is substantially the same procedure as the above-described purge steps, so description thereof will be omitted.

[Third process gas supply step S405]
In the third processing gas supply step S405, H ₂ gas is supplied as a third processing gas (reaction gas) to the wafer 200 to which WFx has been adsorbed.

₍ H2 gas supply)
A valve 334 is opened to allow H ₂ gas, which is a reaction gas, to flow into the gas supply pipe 330 . The flow rate of H ₂ gas is adjusted by the MFC 332 , supplied into the processing chamber 201 through the gas supply hole 430 a of the nozzle 430 , and exhausted through the exhaust pipe 231 . At this time, H ₂ gas is supplied to the wafer 200 . At the same time, the valve 534 is opened to flow an inert gas such as N ₂ gas into the gas supply pipe 530 . The N ₂ gas flowing through the gas supply pipe 530 is adjusted in flow rate by the MFC 532 , supplied into the processing chamber 201 together with the H ₂ gas, and exhausted through the exhaust pipe 231 . At this time, in order to prevent the H ₂ gas from entering the nozzles 410 and 420, the valves 514 and 524 are opened to allow the N ₂ gas to flow through the gas supply pipes 510 and 520. N ₂ gas is supplied into the processing chamber 201 through gas supply pipes 310 and 320 and nozzles 410 and 420 and exhausted through an exhaust pipe 231 .

At this time, the APC valve 243 is adjusted to set the pressure in the processing chamber 201 within the range of 1 to 3990 Pa, for example. The supply flow rate of H ₂ gas controlled by the MFC 332 is, for example, a flow rate within the range of 0.1 to 50 slm. The supply flow rates of the N ₂ gas controlled by the MFCs 512, 522, and 532 are, for example, within the range of 0.1 to 20 slm. The time for which the H ₂ gas is supplied to the wafer 200 is set within the range of 0.1 to 20 seconds, for example. At this time, the temperature of the heater 207 is set such that the temperature of the wafer 200 is within the range of 200 to 600.degree. The gases flowing in the processing chamber 201 are only H ₂ gas and N ₂ gas. By supplying the H ₂ gas, a third film, for example less than one atomic layer, is formed on the wafer 200 (underlying film on the surface). A W layer is formed as a metal layer having a thickness of about several atomic layers.

Although an example in which the second processing gas supply step S403 and the third processing gas supply step S405 are separately performed has been described here, the present invention is not limited to this, and the second processing gas supply step S403 and the third processing gas supply step S403 are performed separately. S405 may be configured to be performed at the same time. By performing the second processing gas supply step S403 and the third processing gas supply step S405 separately, effects such as reduction of F concentration in the main film and improvement of coverage can be obtained. On the other hand, by simultaneously performing the second processing gas supply step S403 and the third processing gas supply step S405, although these effects cannot be expected, the film formation rate can be improved, and the throughput can be improved. .

[Purge step S406]
Next, a purge step S406 is performed. In the purge step S406, H ₂ gas remaining in the processing chamber 201 that has not reacted or that has contributed to the formation of the W layer is removed from the processing chamber 201 . Note that the purge step S406 is substantially the same procedure as the purge steps described above, so description thereof will be omitted.

[Determination step S407]
Next, a determination step S407 is performed. In the determination step S407, it is determined whether or not the second processing gas supply step S403 and the third processing gas supply step S405 have been performed a predetermined number of times. If it has been performed the predetermined number of times, a YES (Y) determination is made, the main film forming step S400 is terminated, and the next step is performed. If it has not been performed a predetermined number of times, it is determined as No (N), and the main film forming step S400 is performed again.

After the main film forming step S400, an atmosphere adjusting step S308 and a substrate unloading step S309 are performed. Each is described below.

(Atmosphere adjustment step S308)
N ₂ gas is supplied into the processing chamber 201 from each of the gas supply pipes 510 , 520 and 530 and exhausted from the exhaust pipe 231 . The N ₂ gas acts as a purge gas, thereby purging the inside of the processing chamber 201 with an inert gas, thereby removing residual gas and by-products from the processing chamber 201 (afterpurge). After that, the atmosphere in the processing chamber 201 is replaced with an inert gas (inert gas replacement), and the pressure in the processing chamber 201 is returned to normal pressure (atmospheric pressure recovery).

(Substrate Unloading Step S309)
After that, the seal cap 219 is lowered by the boat elevator 115 to open the lower end of the reaction tube 203 . Then, the processed wafers 200 supported by the boat 217 are unloaded from the lower end of the reaction tube 203 to the outside of the reaction tube 203 (boat unloading). After that, the processed wafers 200 are taken out from the boat 217 (wafer discharge).

(3) Effects of the embodiment
According to this example embodiment, one or more of the following effects can be obtained. (a) A dense W layer can be formed on the TiN film. (b) The resistivity of the W film can be reduced. For example, as indicated by ▴ in FIG. 9, according to the present technology, the resistivity can be reduced compared to the conventional technology ♦. (c) It is possible to improve the resistivity while improving the coverage.

The embodiments of the present disclosure have been specifically described above. However, the present disclosure is not limited to the above-described embodiments, and can be variously modified without departing from the scope of the present disclosure.

The above-mentioned first film means a film containing a first element as a main component, the second film means a film containing a second element as a main component, and the third film means a film containing a second element. It means a film whose main component is an element. Although Si has been described as an example of the first element, the technique of the present disclosure may be applicable to any Group 14 element. For example, there is germanium (Ge). Also, the second element is a metal element. Here, the main component in the present disclosure means a film having an atomic ratio of 50% or more in the film composition, preferably 90% or more. By increasing the atomic ratio of the film composition, the above-mentioned reaction efficiency is increased, making it possible to obtain a desired film.

In the above description, WF ₆ is used as the second processing gas, but the present invention is not limited to this, and titanium tetrachloride (TiCl ₄ ), tantalum tetrachloride (TaCl ₄ ), tungsten hexachloride (WCl ₆ ), tungsten pentachloride ( WCl ₅ ), molybdenum tetrachloride (MoCl ₄ ), silicon tetrachloride (SiCl ₄ ), disilicon hexachloride (Si ₂ Cl ₆ , hexachlorodisilane (HCDSS)) and other halogen-containing gases and films formed using them Seeds can be applied.

If the second processing gas is a gas containing a halogen element and a metal element, it reacts with the Si film as the first film formed on the wafer 200 to reform the first film into the second film. may be forced to Here, halogen elements are fluorine (F), chlorine (Cl), bromine (Br), and iodine (I). Metal elements are, for example, tungsten (W), titanium (Ti), molybdenum (Mo), ruthenium (Ru), aluminum (Al), hafnium (Hf), zirconium (Zr), lanthanum (La), and the like.

In the above description, SiH ₄ is used as a Si-based raw material as the first processing gas or a processing gas different from the first processing gas. (Si ₂ H ₆ ), trisdimethylaminosilane (SiH[N(CH ₃ ) ₂ ] ₃ ), and the like.

Alternatively, the above-described silane-based gas may be used as the first processing gas, and a halosilane-based gas may be used as a processing gas different from the first processing gas. By using two kinds of processing gases in this way, it is possible to improve the flatness of the film. Here, the halosilane-based gas is a silane-based gas having a halogen group. Halogen groups include halogen elements such as chlorine (Cl), fluorine (F), bromine (Br), and iodine (I). As the halosilane-based gas, for example, a raw material gas containing Si and Cl, that is, a chlorosilane-based gas can be used. A chlorosilane-based gas acts as a Si source. As the chlorosilane-based gas, for example, hexachlorodisilane (Si2Cl6, abbreviation: HCDS) gas, dichlorosilane (SiH2Cl2, abbreviation: DCS) gas, or the like can be used.

In the above description, Si-based raw materials are used as the first processing gas or a processing gas different from the first processing gas. It can be. For example, a gas such as diborane (B ₂ H ₆ ) gas, phosphine (PH ₃ ) gas, or the like can be applied.

Also, in the above description, H ₂ gas is used as the third processing gas, but the present invention is not limited to this, and any gas capable of reducing halogen-based materials may be used.

In the above description, a configuration in which film formation is performed using a batch-type substrate processing apparatus that processes a plurality of substrates at once has been described. The present invention can also be suitably applied when film formation is performed using a single substrate processing apparatus for processing substrates.

Also, in the above description, an example using a wafer as a semiconductor substrate has been shown, but a substrate made of other materials is also possible. For example, the present invention can be applied to substrate processing using materials such as ceramic substrates and glass substrates.

Although various exemplary embodiments and examples of the present disclosure have been described above, the present disclosure is not limited to those embodiments and examples, and can be used in combination as appropriate.

10 substrate processing apparatus 121 controller 200 wafer (substrate)
201 processing chamber

Claims (23)

housing the substrate in a processing chamber;
a first film forming step of supplying a first process gas containing a first element to the substrate to form a first film containing the first element on the substrate;
A second process gas containing a second element is supplied to the film containing the first element through a flash tank to remove the first element from the first film and remove the second element. a second film forming step of modifying the second film containing
A substrate processing method comprising: 2. The substrate processing method according to claim 1, wherein said second process gas is continuously supplied in said second film forming step. 2. The substrate processing method according to claim 1, wherein said second process gas is intermittently supplied in said second film forming step. 4. The method according to any one of claims 1 to 3 , wherein the first film forming step includes supplying the first processing gas and a processing gas containing the first element and different from the first processing gas. The substrate processing method described. 5. The substrate processing method according to claim 4 , wherein said first process gas and a process gas different from said first process gas are supplied alternately in said first film forming step. the first processing gas is a raw material containing silicon and hydrogen and not containing halogen;
6. The substrate processing method according to claim 4 , wherein the processing gas different from the first processing gas is a raw material containing silicon, hydrogen and halogen. The first processing gas is a silane-based raw material,
6. The substrate processing method according to claim 4 , wherein the processing gas different from the first processing gas is a halosilane-based raw material. and a third film forming step of supplying the second processing gas and the third processing gas to the second film to further form a third film containing a second element on the substrate. The substrate processing method according to any one of claims 1 to 7 . 9. The substrate processing method according to claim 8 , wherein said second process gas and said third process gas are supplied alternately in said third film forming step. 10. The substrate processing method according to claim 1 , wherein the first element is a Group 14 element, and the second element is a metal element. the first film is a film containing the first element as a main component;
The substrate processing method according to any one of claims 1 to 10 , wherein the second film is a film containing the second element as a main component. The substrate processing method according to claim 8 , wherein the third film is a film containing the second element as a main component. housing the substrate in a processing chamber;
a first film forming step of supplying a first process gas containing a first element to the substrate to form a first film containing the first element on the substrate;
supplying a second process gas containing a second element to the film containing the first element to remove the first element from the first film to form a second film containing the second element; and a second film formation step that reforms into
A substrate processing method comprising, in the first film forming step, supplying the first processing gas and a processing gas containing the first element and different from the first processing gas. housing the substrate in a processing chamber;
a first film forming step of supplying a first process gas containing a first element to the substrate to form a first film containing the first element on the substrate;
supplying a second process gas containing a second element to the film containing the first element to remove the first element from the first film to form a second film containing the second element; A second film formation step of modifying into
a third film forming step of supplying the second process gas and the third process gas to the second film to further form a third film containing a second element on the substrate;
A substrate processing method comprising: a processing chamber for processing substrates;
a first processing gas supply unit that supplies a first processing gas containing a first element to the substrate in the processing chamber;
a second processing gas supply unit that supplies a second processing gas containing a second element to the substrate in the processing chamber;
a flash tank provided in the second processing gas supply unit;
a process of supplying the first process gas to the substrate to form a film containing the first element on the substrate; and supplying the second processing gas to the film to remove the first element from the first film and reform the film into a second film containing the second element. a controller configured to control the first process gas supply and the second process gas supply;
A substrate processing apparatus having a processing chamber for processing substrates;
a first processing gas supply unit that supplies a first processing gas containing a first element to the substrate in the processing chamber;
a second processing gas supply unit that supplies a second processing gas containing a second element to the substrate in the processing chamber;
a process of supplying the first process gas to the substrate to form a film containing a first element on the substrate; a process of supplying a process gas to remove the first element from the first film to modify it into a second film containing the second element; and a film containing the first element on the substrate. in the process of forming the first process gas and the process of supplying the first process gas and a process gas containing the first element and different from the first process gas. a controller configured to control 2 the process gas supply;
A substrate processing apparatus having a processing chamber for processing substrates;
a first processing gas supply unit that supplies a first processing gas containing a first element to the substrate in the processing chamber;
a second processing gas supply unit that supplies a second processing gas containing a second element to the substrate in the processing chamber;
a process of supplying the first process gas to the substrate to form a film containing a first element on the substrate; a process of supplying a process gas to remove the first element from the first film to reform it into a second film containing the second element; supplying a processing gas and a third processing gas to further form a third film containing a second element on the substrate; a controller configured to control the feeder;
A substrate processing apparatus having a step of accommodating the substrate in the processing chamber;
a first film forming procedure of supplying a first process gas containing a first element to the substrate to form a film containing the first element on the substrate;
A second process gas containing a second element is supplied to the first film containing the first element through a flash tank to remove the first element from the first film and remove the second element from the first film. and a second film forming procedure for modifying the second film containing the element of (1) to the substrate processing apparatus by a computer. a step of accommodating the substrate in the processing chamber;
a first film forming procedure of supplying a first process gas containing a first element to the substrate to form a film containing the first element on the substrate;
A second process gas containing a second element is supplied to the first film containing the first element to remove the first element from the first film, thereby forming a second process gas containing the second element. and a second film formation procedure for modifying the film of 2,
In the first film forming procedure, supplying the first processing gas and a processing gas containing the first element and different from the first processing gas;
A program that causes a substrate processing apparatus to execute by a computer. a step of accommodating the substrate in the processing chamber;
a first film forming procedure of supplying a first process gas containing a first element to the substrate to form a film containing the first element on the substrate;
A second process gas containing a second element is supplied to the first film containing the first element to remove the first element from the first film, thereby forming a second process gas containing the second element. a second film formation procedure for modifying the film of 2;
a step of further forming a third film containing a second element on the substrate by supplying the second process gas and the third process gas to the second film;
A program that causes a substrate processing apparatus to execute by a computer. housing the substrate in a processing chamber;
a first film forming step of supplying a first process gas containing a first element to the substrate to form a first film containing the first element on the substrate;
A second process gas containing a second element is supplied to the film containing the first element through a flash tank to remove the first element from the first film and remove the second element. a second film forming step of modifying the second film containing
A method of manufacturing a semiconductor device having housing the substrate in a processing chamber;
a first film forming step of supplying a first process gas containing a first element to the substrate to form a first film containing the first element on the substrate;
supplying a second process gas containing a second element to the film containing the first element to remove the first element from the first film to form a second film containing the second element and a second film formation step that reforms into
The method of manufacturing a semiconductor device, wherein the first film forming step includes supplying the first processing gas and a processing gas containing the first element and different from the first processing gas. housing the substrate in a processing chamber;
a first film forming step of supplying a first process gas containing a first element to the substrate to form a first film containing the first element on the substrate;
supplying a second process gas containing a second element to the film containing the first element to remove the first element from the first film to form a second film containing the second element A second film formation step of modifying into
a third film forming step of supplying the second process gas and the third process gas to the second film to further form a third film containing a second element on the substrate;
A method of manufacturing a semiconductor device having

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