Substrate processing device and substrate processing method

Abstract

This substrate processing device processes a substrate with gases and comprises: an injector having a supply port for introducing the gases into a processing space for processing the substrate; a first gas line and a second gas line for supplying the gases to the injector; and a control unit. The supply port has a first supply port formed in a portion other than the center portion of the injector and a second supply port formed in the center portion of the injector. The gases supplied from the first gas line to the injector are supplied from the first supply port to the processing space, and the gases supplied from the second gas line to the injector are supplied from the second supply port to the processing space. The control unit executes control including determining a first flow rate of the gases to be supplied from the first gas line and a second flow rate of the gases to be supplied from the second gas line on the basis of a memory effect by a bi-product adhering to the surface of a member in the processing space.

Description

Substrate processing apparatus and substrate processing method

[0001] The present disclosure relates to a substrate processing apparatus and a substrate processing method.

[0002] Patent Document 1 discloses a film formation apparatus for forming a SiC film on a silicon carbide (SiC) substrate. The film formation apparatus includes a mounting table on which the SiC substrate is placed, a gas supply mechanism configured to form a flow of source gas from the outside of the mounting table in a direction perpendicular to the central axis of the mounting table, and an induction coil for heating the SiC substrate.

[0003] Japanese Patent No. 7001517

[0004] The technology according to the present disclosure appropriately performs a film formation process in a substrate processing apparatus.

[0005] One aspect of the present disclosure is a substrate processing apparatus that processes a substrate with a gas, the apparatus comprising: an injector having a supply port for introducing the gas into a processing space where the substrate is processed; a first gas line and a second gas line that supply the gas to the injector; and a controller, wherein the supply ports include a first supply port formed in a portion other than a center of the injector and a second supply port formed in the center of the injector, the gas supplied from the first gas line to the injector being configured to be supplied to the processing space from the first supply port, and the gas supplied from the second gas line to the injector being configured to be supplied to the processing space from the second supply port, and the controller performs control that includes determining a first flow rate of the gas to be supplied from the first gas line and a second flow rate of the gas to be supplied from the second gas line based on a memory effect caused by a by-product adhering to a surface of a component in the processing space.

[0006] According to the present disclosure, a film forming process can be appropriately performed in a substrate processing apparatus.

[0007] FIG. 1 is a diagram illustrating an outline of the configuration of a film forming apparatus according to an embodiment. FIG. 2 is a cross-sectional view illustrating an outline of the configuration inside a processing chamber of the film forming apparatus according to an embodiment. FIG. 3 is a diagram illustrating an outline of the configuration of an injector according to an embodiment. FIG. 4 is a flowchart illustrating an outline of a configuration example of a film forming method according to an embodiment. FIG. 5 is a schematic diagram for explaining a memory effect. FIG. 6 is a schematic diagram for explaining a memory effect. FIG. 7 is a flowchart illustrating an outline of the configuration of a flow rate determination method according to a first embodiment. FIG. 8 is a schematic plan view illustrating an outline of gas supply to a wafer. FIG. 9 is a schematic diagram illustrating the relationship between a cumulative film thickness and a doping amount. FIG. 10 is a schematic plan view illustrating an outline of gas supply to a wafer. FIG. 11 is a schematic diagram illustrating the relationship between a cumulative film thickness and a doping amount. FIG. 12 is a graph illustrating an example of measurement results of the relationship between a cumulative film thickness and a doping amount. FIG. 13 is a schematic plan view illustrating an outline of gas supply to a wafer. FIG. 14 is a diagram illustrating the distribution of doping amounts at various portions of a wafer. FIG. 15 is a flowchart illustrating an outline of the configuration of a reference doping amount correction method. FIG. 16 is a flowchart illustrating an outline of the configuration of a flow rate determination method according to a second embodiment. FIG. 17 is a flowchart illustrating an outline of the configuration of a flow rate determination method according to a third embodiment. FIG. 18 is a flowchart illustrating an outline of a configuration example of a film forming method according to a fourth embodiment. FIG. 19 is a flowchart illustrating an outline of a configuration example of a coefficient determination method according to the fourth embodiment.

[0008] Hereinafter, the configuration of the substrate processing apparatus according to this embodiment will be described with reference to the drawings. In this specification and the drawings, elements having substantially the same functional configuration are designated by the same reference numerals, and redundant description will be omitted.

[0009] <Film Forming Apparatus> FIG. 1 is a schematic diagram illustrating the configuration of a film forming apparatus 1 serving as a substrate processing apparatus according to this embodiment. The film forming apparatus 1 includes a substantially rectangular parallelepiped processing vessel 11. An exhaust line 12 is connected to the processing vessel 11, and the processing vessel 11 can be adjusted to a predetermined reduced pressure state (pressure) via the exhaust line 12. The exhaust line 12 has an exhaust pipe 12a connected to the processing vessel 11 at one end. The exhaust pipe 12a is composed of an exhaust manifold or the like, and is connected to a vacuum pump 12b, such as a mechanical booster pump, on the opposite side from the processing vessel side. A pressure adjustment unit 12c, such as an APC (automatic pressure control) valve or a proportional control valve, is provided between the processing vessel 11 and the vacuum pump 12b on the exhaust pipe 12a to adjust the pressure within the processing vessel 11. The processing vessel 11 is also provided with a pressure gauge 13, and the pressure adjustment unit 12c adjusts the pressure within the processing vessel 11 based on the measurement results of the pressure gauge 13.

[0010] The processing vessel 11 has a hollow rectangular prism-shaped processing vessel body 11a with openings at both ends, and side wall portions 11b connected to both ends of the processing vessel body 11a so as to close the openings, and the processing vessel body 11a and the side wall portions 11b are formed of a dielectric material such as stainless steel or quartz.

[0011] An induction coil 14 connected to a high-frequency power source 14a is provided outside the processing vessel body 11a. The induction coil 14 heats the substrate to be processed, for example, by inductively heating a susceptor case 23 (described later) and the like, and then heats the substrate to be processed by radiant heat from the inductively heated susceptor case 23.

[0012] A gas supply mechanism 15 is configured to supply raw material gases and the like that are used as raw materials for film formation into the processing chamber 11. The gas supply mechanism 15 is connected to an injector 16 (described later) that is provided in the processing chamber 11. The gas supply mechanism 15 is connected to a first gas line L １ and the second gas line L ２ The first gas line L １ and the second gas line L ２ are the first supply pipes 15a connected to the injectors 16, respectively. １ and the second supply pipe 15a２ and the first and second supply pipes 15a １ , 15a ２ supply pipe 15b connected to １１ ~15b １６ , 15b ２１ ~15b ２２ It has the following.

[0013] Supply pipe 15b １１ ~15b １６ , 15b ２１ ~15b ２２ Each of the mass flow controllers (MFC) 15c １１ ~15c １６ , 15c ２１ ~15c ２２ and valve 15d １１ ~15d １６ , 15d ２１ ~15d ２２ and is provided.

[0014] First gas line L １ In the supply pipe 15b １１ The source 15e １１ is connected to the supply source 15e １１ From N ２ Similarly, the gas is supplied through the supply pipe 15b. １２ ~15b １６ Each of the supply sources 15e １２ ~15e １６ are connected, and each supply source 15e １２ ~15e １６ From H ２ Gas, SiH ４ Gas, C ３ H ８ Gas, HCl gas, and Ar gas are supplied.

[0015] Second gas line L ２ In the supply pipe 15b ２１ The source 15e ２１ is connected to the supply source 15e ２１ From N ２ Similarly, the gas is supplied through the supply pipe 15b. ２２ The source 15e ２２ is connected and H ２ Gas is supplied.

[0016] In one embodiment, N ２ Gas supply source 15e １１ and source 15e ２１ may be the same supply source. That is, the supply pipe 15b １１ and supply pipe 15b ２１ For N ２ Similarly, H ２ Gas supply source 15e １２ and source 15e ２２ are the same supply source, and from the common supply source, the supply pipe 15b １２ and supply pipe 15b ２２ Against H ２ A gas may be supplied.

[0017] In one embodiment, other gas lines (not shown) are provided to supply other gases or gas mixtures (not shown) to the injector 16. The other gas lines may, for example, be C ２ H ２ Gas, C ２ H ４ Gas or C ２ H ６ There is another source, not shown, that supplies one of the gases.

[0018] When forming an n-type SiC film by epitaxial growth on a SiC substrate as a substrate to be processed, a gas supply pipe 15b is used as a source gas for film formation. １ ~15b ５ From SiH ４ Gas, C ３ H ８ Gas, H ２ Gas, N ２ Gas, HCl gas, etc. are supplied to the processing chamber 11. Note that, in order to form a p-type SiC film, a gas supply source and a gas supply pipe for TMA (trimethylaluminum) gas may be provided.

[0019] When removing foreign matter adhering to the structure inside the processing vessel 11, for example, the gas supply pipe 15b ３ , 15b ６ From H ２One of the following gases, or Ar gas, or a mixture of these gases, is supplied to the processing chamber 11 .

[0020] The above-described film forming apparatus 1 is provided with at least one control unit 100 as shown in FIG. 1 . The control unit 100 processes computer-executable instructions that cause the film forming apparatus 1 to perform the various processes described in this disclosure. The control unit 100 may be configured to control each element of the film forming apparatus 1 to perform the various processes described herein. In one embodiment, part or all of the control unit 100 may be included in the film forming apparatus 1. The control unit 100 may include a processing unit, a storage unit, and a communication interface. The control unit 100 is realized by, for example, a computer. The control unit 100 may be one or more circuits, and may be provided as an integrated unit or partially separated. The functions performed by the processing unit described in this disclosure may be implemented in circuitry or processing circuitry, including general-purpose processors, application-specific processors, integrated circuits, ASICs (Application Specific Integrated Circuits), CPUs (Central Processing Units), conventional circuitry, and / or combinations thereof, programmed to perform the described functions. A processor is considered to be a circuit or processing circuit including transistors and other circuitry. A processor may also be a programmed processor that executes a program stored in a memory unit. This program (computer program product) may be stored in a memory unit in advance or may be acquired via a medium when needed. The medium may be any of various computer-readable storage media, such as a removable storage medium such as a memory card, an optical disc, or a hard disk drive (HDD), and the program may be provided stored on the storage medium. Alternatively, the medium may be a communication line connected to the communication interface, and the program may be distributed by a remote server device or the like. The acquired program is stored in the storage unit and is read from the storage unit and executed by the processing unit.The storage unit may include a storage medium such as a random access memory (RAM), a read-only memory (ROM), an electronically erasable programmable read-only memory (EEPROM), a hard disk drive (HDD), or a solid state drive (SSD), or a combination thereof. The communication interface may communicate with the film forming apparatus 1 via a communication line such as a local area network (LAN). In the present disclosure, a circuit, a unit, or a means is hardware programmed to realize the described function or hardware configured to execute the function. The hardware may be any hardware described in the present disclosure or any hardware known to be programmed to realize the described function or to execute the function. If the hardware is a processor considered to be a type of circuit, the circuit, means, or unit is a combination of hardware and software used to configure the hardware and / or processor.

[0021] <Processing Vessel> Next, the configuration inside the processing vessel 11 will be described. Fig. 2 is a cross-sectional view that schematically illustrates an outline of the configuration inside the processing vessel 11 in the film forming apparatus 1 of Fig. 1. As shown in Fig. 2, the processing vessel 11 is provided with a susceptor 20 on which a SiC substrate (hereinafter, referred to as a wafer W) serving as a substrate to be processed is placed via a holder H, a rotation shaft 21 that rotates and supports the susceptor 20, and an elevator 22 that raises and lowers the holder H on which the wafer W is placed. A susceptor case 23 is also provided inside the processing vessel 11 as a housing unit. The susceptor case 23 has a processing space S that houses the susceptor 20, and a processing gas is supplied to the processing space S from one end of the susceptor 20, passing over the center of the susceptor 20, and reaching the other end of the susceptor 20.

[0022] The susceptor 20 is formed in a disk shape having a recess 20a on its upper surface that is recessed vertically downward, and is installed horizontally inside the processing vessel 11. A holder H fits into the recess 20a. The susceptor 20 is rotated by a rotating shaft 21 about a central axis P of the susceptor 20 and the rotating shaft 21, whereby the holder H is also rotated.

[0023] The susceptor 20 is made of a conductive material that is highly heat-resistant and can be easily heated by induction heating, and is, for example, made of a graphite member whose upper surface is coated with SiC.

[0024] The holder H has a mounting area Ha on its upper surface where the wafer W is mounted. The holder H is made of a conductive material that is highly heat-resistant and can be easily heated by induction heating, and is, for example, made of a graphite member coated with SiC on its upper surface on which the wafer W is mounted. The holder H is, for example, formed in the shape of a disk having a diameter smaller than that of the susceptor 20.

[0025] One end of the rotating shaft 21 is connected to the center of the lower part of the susceptor 20, and the other end passes through the bottom of the processing vessel 11 and reaches below it, and is connected to a rotation drive mechanism (not shown). The rotation drive mechanism rotates the rotating shaft 21, thereby rotating the susceptor 20.

[0026] The lifting unit 22 is used to transfer the wafer W between a wafer W transfer device outside the film forming apparatus 1 and the susceptor 20, and in this example, transfers the holder H on which the wafer W is placed. The lifting unit 22 is raised and lowered by a lifting drive mechanism (not shown), thereby raising and lowering the holder H, i.e., the wafer W.

[0027] The susceptor case 23 is formed in a rectangular parallelepiped shape with openings on two opposing sides, and is structured so that the process gas is supplied through the opening on one side and discharged through the opening on the other side. In this structure, the process gas is supplied onto the wafer W in a direction parallel to the wafer W, which is perpendicular to the central axis P, and is then discharged.

[0028] The susceptor case 23 is made of a conductive material that is highly heat-resistant and can be easily heated by induction heating, and is, for example, made of a graphite member whose surface on the wafer W side is coated with SiC.

[0029] Additionally, a heat insulating material 24 is provided on the outer periphery of the susceptor case 23 to insulate the susceptor case 23 from the processing vessel 11. The heat insulating material 24 is formed, for example, using a fibrous carbon material with a high porosity. Although not shown, a holding structure is provided on the outside of the heat insulating material 24 to hold the heat insulating material 24 while keeping it separated from the processing vessel 11.

[0030] 3 is a diagram showing an outline of the configuration of the injector 16 according to this embodiment. The injector 16 is configured to extend along the susceptor 20 in a direction parallel to the wafer W to be placed on the susceptor 20. A side surface 16s of the injector 16 facing the processing space S is provided with a plurality of first supply ports 16h. １ and second supply port 16h ２ The first supply port 16h is formed. １ and second supply port 16h ２ is the first gas line L １ and the second gas line L ２ 1 and 2 are introduced into the processing space S. In one embodiment, the injector 16 includes a first gas line L １ and the second gas line L ２ The gas supplied from each supply port 16h １ , 16h ２ A diffusion space is provided that is configured to distribute the

[0031] 1st supply port 16h １ is the first gas line L １ The first supply port 16h is configured to introduce the gas supplied from the first supply port 16h into the processing space S. １ is the second supply port 16h ２In an embodiment, when another gas line is provided, a plurality of other supply ports (not shown) for introducing gas supplied from the gas line are provided in the plurality of supply ports 16h. １ can be formed alternately with

[0032] 2nd supply port 16h ２ is the second gas line L ２ The gas supply port 16h is configured to introduce the gas supplied from the supply port 16h into the processing space S. ２ Only one second supply port 16h is formed at the center in the width direction of the side surface portion 16s. ２ are formed in the vicinity of the center in the width direction of the side surface portion 16s.

[0033] <Film Forming Method> Next, a film forming method will be described as a substrate processing method using the film forming apparatus 1. Fig. 4 is a flowchart showing an outline of a configuration example of the film forming method according to this embodiment.

[0034] First, the holder H on which the wafer W is placed is loaded into the processing chamber 11 (step St1 in FIG. 4 ). Specifically, the holder H is loaded into the processing chamber 11 from outside the film forming apparatus 1 via a gate valve (not shown) using a transfer means (not shown) external to the film forming apparatus 1, and positioned above the susceptor 20. Next, the lifting unit 22 is raised, and the holder H is supported by the lifting unit 22. Next, the transfer means is retracted from the processing chamber 11, and the lifting unit 22 is lowered, and the holder H is placed on the susceptor 20.

[0035] After the holder H is loaded, the source gas and the carrier gas are supplied from the gas supply mechanism 15 via the injector 16 into the processing chamber 11 in a direction perpendicular to the central axis P. Simultaneously with the gas supply, the wafer W is heated by applying high frequency power from the high frequency power supply 14a to the induction coil 14, and an n-type SiC film is formed on the wafer W by epitaxial growth (step St2 in FIG. 4 ).

[0036] In step St2, the first gas line L １ In the valve 15d １１~15d １５ is in the open state, and MFC15c １１ ~15c １５ The flow rate is adjusted to introduce N into the processing vessel 11. ２ Gas, H ２ Gas, SiH ４ Gas, C ３ H ８ The second gas line L ２ In the valve 15d ２１ ~15d ２２ is in the open state, and MFC15c ２１ ~15c ２２ The flow rate is adjusted to introduce N into the processing vessel 11. ２ Gas, H ２ At this time, each gas line L １ , L ２ The flow rate of the gas supplied from is a flow rate determined in advance by a method to be described later.

[0037] In step St2, high frequency power is applied from the high frequency power supply 14a to the induction coil 14, thereby heating the wafer W by radiation and heat conduction from the induction-heated holder H, susceptor 20, and susceptor case 23. During film formation, the pressure inside the processing chamber 11 is, for example, 10 Torr to 600 Torr, and the temperature of the wafer W is, for example, 1500°C to 1700°C.

[0038] After the film formation is completed, the holder H supporting the wafer W is unloaded from the processing chamber 11 (step S3). １ ~15d ５is closed, the supply of the source gas and the carrier gas is stopped, and then the elevator 22 is raised to raise the holder H supporting the wafer W. Then, a transfer means external to the film forming apparatus 1 is inserted into the processing chamber 11 via the gate valve and positioned below the holder H. Thereafter, the elevator 22 is lowered, the holder H is transferred from the elevator 22 to the transfer means, and the transfer means is retracted from the processing chamber 11, thereby unloading the holder H holding the wafer W from the processing chamber 11. While the supply of high-frequency power to the induction coil 14 may be interrupted during unloading of the wafer W, it is preferable to supply high-frequency power to the induction coil 14 while controlling the susceptor 20 and the susceptor case 23 to have optimal temperatures for the next process.

[0039] After the holder H is unloaded, the process may return to step S1, and the holder H on which another wafer W is placed may be loaded into the processing vessel 11, and the processes of steps St1 to St3 may be repeated.

[0040] <Flow Rate Determination Method> (First Embodiment) Hereinafter, a method for determining the flow rate of the gas supplied in step St2 according to the first embodiment will be described. Figures 5 to 7 are diagrams for explaining the memory effect. Figure 8 is a flowchart showing an outline of a configuration example of the flow rate determination method according to this embodiment.

[0041] First, the memory effect occurring when a SiC film is formed on a wafer W by epitaxial growth in step St2 in a conventional film formation process using a conventional film formation apparatus will be described with reference to FIGS.

[0042] 5(a) shows the initial state immediately after the susceptor 20 has been replaced or cleaned, for example. In the initial state, no by-products BP adhere to the surface of the susceptor 20. FIG. 5(b) shows the state after the film formation process similar to St2 described above has been repeated multiple times from the state shown in FIG. 5(a), and FIG. 5(c) shows the state after the film formation process has been further repeated multiple times from the state shown in FIG. 5(b). As shown in FIGS. 5(b) and 5(c), when the film formation of St2 is repeated in the substrate processing, N accumulates on the surface of the susceptor 20. ２In some cases, by-products BP including BP may accumulate. In addition, the amount of by-products BP increases as the number of film formation repetitions increases. When a wafer W is placed on the susceptor 20 in a state where by-products BP have accumulated and a substrate is processed, the amount of by-products BP increases. ２ A part of the by-product BP is etched by the gas. At this time, nitrogen atoms N are liberated from the by-product BP and are doped into the SiC film of the wafer W in the vicinity of the by-product BP. As a result, the doping amount of nitrogen in a certain part of the SiC film of the wafer W (hereinafter simply referred to as "doping amount") becomes smaller than the N supplied in St2. ２ The doping amount may be higher than expected depending on the gas. This effect of increasing the doping amount due to the accumulation of by-products BP when film formation is repeated is called the memory effect.

[0043] As shown in FIG. 6, the by-products BP are accumulated on the surface of the susceptor 20 and the surface of the susceptor case 23. In addition, H ２ Because gas is supplied from the injector 16 and the wafer W is rotated by the rotation shaft 21 during film formation, the SiC film is doped more heavily at the peripheral portion E of the wafer W near the injector 16. In Figure 7, areas with relatively high doping amounts are indicated by dark shading, and areas with relatively low doping amounts are indicated by light shading. As shown in Figure 7, due to the memory effect, the peripheral portion E of the wafer W is doped more heavily than the central portion C. Furthermore, due to the memory effect, the increase in the doping amount at the peripheral portion E becomes more pronounced as the number of film formation repetitions increases.

[0044] In the flow rate determination method according to the present embodiment, the contribution of the memory effect to the doping amount is evaluated, and the flow rate of the first gas line L １ and the second gas line L ２ The flow rate of the gas to be supplied from the

[0045] First, the first gas line L １ and the second gas line L ２ For each of the above, the change in the doping amount at each portion of the wafer W due to the number of times the film formation is repeated is evaluated (step St101 in FIG. 8).１ Only or the second gas line L ２ When film formation is performed by supplying each gas in the same manner as in St2 using only the dopant gas, the doping amount [cm －３ ] is measured. １ , L ２ The processing time is assumed to be equal.

[0046] Here, the cumulative film thickness is the integrated value of the thickness of the film formed on each wafer W when multiple wafers W are processed from the time when the susceptor 20 is in the initial state (see FIG. 5A). Note that the film thickness of each wafer W when calculating the cumulative film thickness may be a target value or a predicted value when forming a film on each wafer W.

[0047] In this embodiment, the portions of the wafer W where the change in doping amount is measured in step St101 are the central portion C, the peripheral portion E, and the intermediate portion M, which is the radially intermediate position between the central portion C and the peripheral portion E of the wafer W. When measuring the doping amounts of the central portion C, the intermediate portion M, and the peripheral portion E of the wafer W, the doping amounts are measured at multiple points (for example, four points) in the circumferential direction of each portion, and the average value of the measured values ​​can be used as the doping amount of that portion. Note that other representative values, such as the median, may be used instead of the average value.

[0048] 9 and 10 show the first gas line L １ When film formation is performed using only the first gas line L (FIG. 9), ２ 9A and 10A are plan views showing an outline of gas supply to a wafer W from one of the gas lines. FIGS. 9B and 10B are views showing the relationship between cumulative film thickness and doping amount when a film is formed using each gas line.

[0049] As shown in FIG. 9A, the first gas line L １ The injector 16 has supply ports 16h arranged at approximately equal intervals in the width direction except for the central portion thereof. １9B(b), gas (arrows in FIG. 9A) is introduced into the intermediate portion M and peripheral portion E of the wafer W. Therefore, in FIG. 9B(a), when the cumulative film thickness is small and the memory effect is small, the doping amount is high in the intermediate portion M and peripheral portion E of the wafer W and low in the vicinity of the central portion C. On the other hand, in FIG. 9B(b), when the cumulative film thickness is large, the doping amount in the peripheral portion E increases relatively due to the memory effect.

[0050] As shown in FIG. 10A, the second gas line L ２ The injector 16 has one supply port 16h formed in the center of the width direction thereof or a plurality of supply ports 16h formed in the vicinity of the center thereof. ２ 10B(b), gas (arrows in FIG. 10A) is introduced to the vicinity of the central portion C of the wafer W. Therefore, in FIG. 10B(a), when the cumulative film thickness is small and the memory effect is small, the doping amount is high near the central portion C of the wafer W and low near the peripheral portion E of the wafer W. On the other hand, in FIG. 10B(b), when the cumulative film thickness is large, the doping amount at the peripheral portion E increases relatively due to the memory effect.

[0051] 11 is a graph showing an example of the measurement results when measuring the change in doping amount at each part of the wafer W depending on the cumulative film thickness in step St101. The horizontal axis (x-axis) of FIG. 11 is the cumulative film thickness [μm], and the vertical axis (y-axis) is the cumulative film thickness [μm]. ２ Doping amount per gas supply [cm －３ / cc]. The first gas line L １ The white plot is for the second gas line L ２ The central portion C of the wafer W is indicated by a circle plot, the intermediate portion M by a square plot, and the peripheral portion E by a triangle plot.

[0052] In addition, N ２ The doping amount y per gas flow rate is calculated by ２ In the following description, the term "doping sensitivity" or simply "sensitivity" may be used to indicate the sensitivity of the change in doping amount to the change in gas flow rate.

[0053] From FIG. 11, the first gas line L １and the second gas line L ２ It can be seen that the doping amount at each portion of the wafer W increases with a specific gradient as the cumulative film thickness increases. That is, the doping sensitivity y is typically expressed by a linear equation (y=ax+b) using an arbitrary gradient a and intercept b. The intercept b is the N ２ Doping amount per 1 sccm of gas flow rate [cm －３ / sccm]. In the following description, the intercept b is referred to as the "reference doping amount b." The solid line, dashed line, and dashed-dotted line in FIG. 11 represent linear equations calculated from the plots of the measurement results. The slope a and the reference doping amount b are determined from the measurement results of step St101.

[0054] Next, based on the relationship between the cumulative film thickness and the change in the doping amount determined in step St101, the first gas line L １ and the second gas line L ２ The doping amount at each portion of the wafer W when gas is supplied simultaneously from both the doping amount D at the center C of the wafer W is estimated and calculated (step St102 in FIG. 8). Ｃ , the doping amount D in the middle part M Ｍ , and the doping amount D in the peripheral portion E Ｅ FIG. 12A shows the first gas line L １ and the second gas line L ２ 12B is a schematic plan view showing an outline of gas supply from both the first gas line L and the second gas line L to the wafer W. １ and the second gas line L ２ 10 is a diagram showing the distribution of the doping amount at each part of the wafer W estimated when gas is supplied from both the first and second electrodes simultaneously.

[0055] Next, the flow rate of each gas line L during processing of an arbitrary wafer W for which the flow rate is to be determined (hereinafter, referred to simply as "QC time" for quality control time) １ , L ２ N to be supplied from ２ A target value of the gas flow rate is determined (step St103 in FIG. 8). ２ The target value of the gas flow rate is determined, for example, as follows.

[0056] First gas line L １ N to be supplied from ２ The target value of the gas flow rate is N Ｌ１ [sccm], second gas line L ２ N to be supplied from ２ The target value of the gas flow rate is N Ｌ２ [sccm]. １ The doping sensitivity of the central part C is expressed as y Ｌ１Ｃ , the doping sensitivity of the middle part M is y Ｌ１Ｍ , the doping sensitivity of the peripheral area E is y Ｌ１Ｅ Similarly, the second gas line L ２ The doping sensitivity of the central part C is expressed as y Ｌ２Ｃ , the doping sensitivity of the middle part M is y Ｌ２Ｍ , the doping sensitivity of the peripheral area E is y Ｌ２Ｅ Each value of the doping sensitivity is calculated by substituting the cumulative film thickness x at the time of QC into the linear expression determined in step St101.

[0057] At this time, in the above step St102, the doping amount D Ｃ , the doping amount D in the middle part M Ｍ , and the doping amount D in the peripheral portion E Ｅ is calculated by the following formulas (1) to (3).

[0058] Furthermore, in this embodiment, a desired constraint condition for the doping amount is set. In this embodiment, the constraint condition is the doping amount D Ｃ , D Ｅ (Equation (4) below) In addition, the arithmetic mean value of the doping amount at each portion of the wafer W is set to a predetermined target value D ＴＧＴ (Equation (5) below).

[0059] By solving the simultaneous equations (1) to (5) above, the unknown N Ｌ１ , N Ｌ２ , D Ｃ , D Ｍ , D Ｅ Therefore, the target value N Ｌ１ , NＬ２ can be determined.

[0060] In step St2 during QC, the first gas line L １ and the second gas line L ２ From N ２ When supplying gas, the target value N determined by the above flow rate determination method is Ｌ１ , N Ｌ２ This allows the doping amount at each portion of the wafer W to be set to a suitable value that satisfies the constraints of the above formulas (4) and (5). From this perspective, the suitable constraints are not limited to the examples of the above formulas (4) and (5), and the target value N Ｌ１ , N Ｌ２ Other conditions may be employed as desired, as long as a solution for .times. ...

[0061] Note that steps St101 to St103 in the flow rate determination method may be executed in advance prior to steps St1 to St3 in the film forming method. In this case, the target value N corresponding to the cumulative film thickness determined by the flow rate determination method is Ｌ１ , N Ｌ２ may be stored in the control unit 100 in St103, for example, and read out in the above-mentioned step St2. Also, steps St101 and St102 in the flow rate determination method may be executed in advance, and just before step St2 for the wafer W to be processed, a target value N corresponding to the accumulated film thickness at that time may be set. Ｌ１ , N Ｌ２ may be calculated in St103.

[0062] (Correction of Reference Doping Amount b) In one embodiment, the reference doping amount b calculated in step St101 above is corrected each time a film formation process is performed on a desired number of wafers W. The correction of the reference doping amount b can be performed, for example, as follows. Fig. 13 is a flowchart showing an outline of an example of a method for correcting the reference doping amount b.

[0063] First, the first gas line L １ Only or the second gas line L ２When a film is formed by supplying each gas to the wafer W using only the first gas line L in the same manner as in St2, the doping amount at each portion of the wafer W is measured (step St111 in FIG. 13). For convenience of explanation, the following description will be given using numerical examples. For example, １ to 150 (sccm) N ２ When a film is formed by supplying a gas containing the gas, the doping amount in the central portion C is 1.5×10 １６ (cm －３ ) In addition, the second gas line L ２ to 100 (sccm) N ２ When a film is formed by supplying a gas containing the gas, the doping amount in the central portion C is 1.6×10 １６ (cm －３ ) At this time, the first gas line L １ and the second gas line L ２ N ２ Doping amount ratio D of central portion C per gas flow rate Ｌ２ / D Ｌ１ is calculated by the following equation (6) (step St112 in FIG. 13).

[0064] The above formula (6) is the first gas line L １ to 1.6 (sccm) N ２ The doping amount when the gas is supplied and the film is formed, and the second gas line L ２ to 1 (sccm) N ２ Similarly, for the middle portion M and the peripheral portion E, the doping amount ratio D Ｌ２ / D Ｌ１ is calculated.

[0065] Next, at the time of correction, the doping amount at each portion of the wafer W after the film formation process is measured (step 113 in FIG. 13). For example, if the doping amount at the center C of the wafer W after the film formation process is 1.05×10 １６ (cm －３ ) In addition, in the processing of the wafer W, the first gas line L １ From N ２ The gas flow rate is 100 sccm, and the second gas line L ２ From N２ The gas flow rate is assumed to be 50 sccm. １ , L ２ The processing time in the first gas line L １ The reference doping amount b at the center C of the wafer W for Ｌ１Ｃ is the doping amount ratio D calculated by equation (6) Ｌ２ / D Ｌ１ = 1.6, and is calculated by the following formula (7). ２ The reference doping amount b at the center C of the wafer W for Ｌ２Ｃ is calculated by the following formula (8) (step 114 in FIG. 13).

[0066] The reference doping amount b is also calculated in the same manner for the middle portion M and the peripheral portion E. The calculated reference doping amount b is used as the reference doping amount b in step St101 in the flow rate determination method for other wafers W to be processed after the wafer W.

[0067] By correcting the reference doping amount b for each desired number of wafers W or for each desired cumulative film thickness, it is possible to perform film formation processing on a plurality of wafers W while maintaining the in-plane uniformity of the doping amount on the wafers W. The timing of performing the correction is not particularly limited, but the correction may be performed for each processing of a number of wafers W that is empirically known to deteriorate the in-plane uniformity of the doping amount on the wafers W since the previous correction.

[0068] In the above steps, an example in which measurements and calculations are performed using the gas flow rate [sccm] has been described, but of course, this is not limited to this, and measurements and calculations may be performed using the gas supply rate [cc]. In this case, a target value of the gas supply rate is calculated in step St103, but a target value of the gas flow rate appropriately calculated based on the target value of the gas supply rate can be used in step St2.

[0069] Second Embodiment A method for determining the flow rate of the gas supplied in step St2 according to a second embodiment will now be described. Fig. 14 is a flowchart showing an outline of a configuration example of the flow rate determination method according to this embodiment.

[0070] In the first embodiment described above, when evaluating the doping amount at each portion of the wafer W, three positions, namely, the central portion C, the intermediate portion M, and the peripheral portion E of the wafer W, are evaluated. In contrast, in the second embodiment, the doping amount is evaluated at a plurality of arbitrary positions i within the surface of the wafer W. Note that position i is one or more predetermined target positions for doping amount measurement. Here, the "target positions for doping amount measurement" may refer to a region within the surface of the wafer W when the doping amounts are measured at a plurality of points included in the region and an arbitrary representative value, such as the average of the measured values, is determined.

[0071] In the first embodiment, the doping sensitivity y is evaluated as a linear expression of the cumulative film thickness x from the initial state of the susceptor 20. However, the inventors have conducted extensive research and confirmed that there is a memory effect due to by-products BP (see FIG. 6 ) accumulated in the susceptor case 23. Therefore, in the second embodiment, the cumulative film thickness of the susceptor case 23 is included in the evaluation in addition to the cumulative film thickness of the susceptor 20.

[0072] The variables used in the flow rate determination method according to the second embodiment are set as follows: y Ｌ１ｉ : First gas line L １ Doping sensitivity at position i [cm －３ / sccm] y Ｌ２ｉ : Second gas line L ２ Doping sensitivity at position i [cm －３ / sccm] N Ｌ１ : 　 First gas line L １ N to be supplied from ２ Target gas flow rate [sccm] N Ｌ２ : 　 Second gas line L ２ N to be supplied from ２ Target gas flow rate [sccm] D ｉ : 　　Doping amount at position i [cm －３ ] i: Position in the surface of the wafer W m １ : 　　 Accumulated film thickness from the initial state of the susceptor 20 [μm] m ２ : 　　 Accumulated film thickness from the initial state of the susceptor case 23 [μm] a １ｉ : 　 First gas line L １ The coefficient of the ratio of the doping sensitivity to the cumulative film thickness of the susceptor 20 at the position i [cm －３ / μm / sccm] a ２ｉ : 　 Second gas line L ２ The coefficient of the ratio of the doping sensitivity to the cumulative film thickness of the susceptor 20 at the position i [cm －３ / μm / sccm] a ３ｉ : 　 First gas line L １ The coefficient of the ratio of the doping sensitivity to the cumulative film thickness of the susceptor case 23 at the position i [cm －３ / μm / sccm] a ４ｉ : 　 Second gas line L ２ The coefficient of the ratio of the doping sensitivity to the cumulative film thickness of the susceptor case 23 at the position i [cm －３ / μm / sccm]b １ｉ : 　 First gas line L １ Reference doping amount [cm －３ / sccm] b ２ｉ : 　 Second gas line L ２ Reference doping amount [cm －３ / sccm]

[0073] At this time, the doping amount D at the position i is ｉ satisfies the relationship of the following formula (9).

[0074] In addition, each gas line L １ , L ２ Doping sensitivity y at position i according to Ｌ１ｉ , y Ｌ２ｉsatisfies the relationships of the following formulas (10) and (11).

[0075] In one embodiment, to simplify the calculations, a ３ｉ = a ４ｉ In this case, the doping sensitivity y Ｌ２ｉ satisfies the relationship of the following formula (12): When this approximation is performed, the part written as formula (11) in the following description should be read as formula (12).

[0076] Based on the above, the specific content of the flow rate determination method according to the second embodiment will be described. First, similar to step St101 according to the first embodiment, the first gas line L １ and the second gas line L ２ The film formation process of the wafer W is repeated, and the doping amount D ｉ The actual doping amount D is measured (step St201 in FIG. 14). ｉ is y Ｌ１ｉ axis (or y Ｌ２ｉ axis), m １ axis, m ２ From the plot of the measurement results, the coefficient a is calculated based on the above equations (10) and (11). １ｉ , a ２ｉ , a ３ｉ , a ４ｉ , and the reference doping amount b １ｉ , b ２ｉ The reference doping amount b １ｉ , b ２ｉ Similarly to steps St111 to St114 in the first embodiment, values ​​obtained for each desired number of wafers W may be used.

[0077] Next, the cumulative film thickness m of the susceptor 20 at the time when the flow rate is to be determined (at QC) １ （ＱＣ） and the cumulative film thickness m of the susceptor case 23 ２ （ＱＣ） Substituting these into the above equations (10) and (11), the first gas line L １ and the second gas line L ２ Doping sensitivity yＬ１ｉ （ＱＣ） and y Ｌ２ｉ （ＱＣ） is calculated (step St202 in FIG. 14).

[0078] Next, the target value D of the doping amount predetermined for the position i is calculated. ＴＧＴｉ [cm －３ ], and from the above formula (9), the first gas line L １ and the second gas line L ２ N ２ Target gas flow rate N Ｌ１ （ＱＣ） , N Ｌ２ （ＱＣ） The following equation (15) is obtained as the relational expression that must be satisfied.

[0079] Next, N at QC is calculated by an optimization method so as to satisfy the above formula (15). ２ Target gas flow rate N Ｌ１ （ＱＣ） , N Ｌ２ （ＱＣ） (Step St203 in FIG. 14). The optimization method may be, for example, the least squares method. Specifically, in the least squares method, a certain N ２ Target gas flow rate N Ｌ１ （ＱＣ） , N Ｌ２ （ＱＣ） When using the doping amount D ｉ and the target value D ＴＧＴｉ N so that the sum of the squares of the differences between ２ Target gas flow rate N Ｌ１ （ＱＣ） , N Ｌ２ （ＱＣ） is determined.

[0080] In one embodiment, after the QC, a desired number of wafers, for example, j wafers W, are processed (hereinafter referred to as "QC+j"). ２ Target gas flow rate N Ｌ１ （ＱＣ＋ｊ） , N Ｌ２ （ＱＣ＋ｊ）is determined by optimization (step St210 in FIG. 14). ２ Target gas flow rate N Ｌ１ （ＱＣ＋ｊ） , N Ｌ２ （ＱＣ＋ｊ） is determined as follows, for example.

[0081] The difference in cumulative film thickness of the susceptor 20 between QC and QC+j is Δm １ｊ , the difference in cumulative film thickness of the susceptor case 23 is Δm ２ｊ The amount of change in doping amount due to the increase in the cumulative film thickness from time QC to time QC+j is expressed as D （ａｃｃｕｍ） ｉｊ In addition, each gas line L at QC+j １ , L ２ The doping sensitivity at position i is expressed as y Ｌ１ｉｊ , y Ｌ２ｉｊ and the adjustment amount of the doping sensitivity from the time of QC at the time of QC+j is Δy Ｌ１ｉｊ , Δy Ｌ２ｉｊ are defined by the following equations (16) and (17).

[0082] At this time, the adjustment amount Δy of the doping sensitivity Ｌ１ｉｊ , Δy Ｌ２ｉｊ Regarding the above, from the above formulas (10) and (11), the following formulas (18) and (19) hold.

[0083] Furthermore, from the above formula (9), the doping amount change amount D （ａｃｃｕｍ） ｉｊ The following equation (20) holds true for

[0084] By the way, the target value D of the doping amount ＴＧＴｉ The doping amount D at a certain position i during QC is calculated to approximate （ＱＣ） ｉ (the left side of the above formula (15)) （ＱＣ） ｉ and the target value of the doping amount D ＴＧＴｉ The error is the difference between these (D ＴＧＴｉ -D （ＱＣ） ｉ) and the doping amount change D calculated by the above formula (20). （ａｃｃｕｍ） ｉｊ Based on this, the target value D of the doping amount at QC+j ＴＧＴｉｊ is calculated by the following formula (21).

[0085] Furthermore, N from time QC at time QC+j ２ Adjustment amount ΔN of the target value of the gas flow rate Ｌ１ｊ , ΔN Ｌ２ｊ are defined by the following equations (22) and (23).

[0086] At this time, from the above equations (16) to (21), the adjustment amount ΔN Ｌ１ｊ , ΔN Ｌ２ｊ The following equation (24) is obtained as the relational expression that must be satisfied.

[0087] N at QC+j is calculated by an optimization method so as to satisfy the above formula (24). ２ Adjustment amount ΔN of the target value of the gas flow rate Ｌ１ｊ , ΔN Ｌ２ｊ The optimization method may be, for example, the least squares method. ２ Target gas flow rate N Ｌ１ （ＱＣ＋ｊ） , N Ｌ２ （ＱＣ＋ｊ） Constraints may be set such that is determined within desired constraints.

[0088] According to the flow rate determination method of the second embodiment, it is possible to evaluate the doping amount at a plurality of arbitrary positions i on the surface of the wafer W. This improves the degree of freedom in measuring and adjusting the doping amount on the surface of the wafer W. Also, by setting the portion of the wafer W where the doping amount needs to be more accurately controlled as position i, it is possible to more accurately adjust the doping amount at that position i. Also, after QC, it is possible to more accurately adjust the N when the desired processing has progressed. ２ Adjustment amount ΔN of the target value of the gas flow rate Ｌ１ｊ , ΔN Ｌ２ｊ This allows the doping amount to be controlled to a desired amount, taking into consideration the memory effect after the process has progressed from the QC time.

[0089] In addition, step St210 is performed by steps St201 to St203 to determine the N ２ This is not limited to when the target value of the gas flow rate is determined, but can also be performed in other cases. ２ When the target value of the gas flow rate is known, the N ２ Target gas flow rate N Ｌ１ （ＱＣ＋ｊ） , N Ｌ２ （ＱＣ＋ｊ） This can also be done when determining

[0090] Third Embodiment A method for determining the flow rate of the gas supplied in step St2 according to a third embodiment will now be described. Fig. 15 is a flowchart showing an outline of a configuration example of the flow rate determination method according to this embodiment.

[0091] In the first and second embodiments described above, in order to obtain a desired doping amount distribution within the surface of the wafer W, the first gas line L １ and the second gas line L ２ N ２ In the third embodiment, the target value of the gas flow rate is optimized, and at the same time, the film thickness distribution within the surface of the wafer W is optimized.

[0092] Specifically, the second gas line L ２ H supplied from ２ It is considered that the gas may affect both the doping amount distribution and the film thickness distribution within the surface of the wafer W. Therefore, in the third embodiment, the first gas line L １ and the second gas line L ２ N ２ At the same time as optimizing the target value of the gas flow rate, the second gas line L ２ H supplied from ２ Optimize the gas flow rate.

[0093] The variables used in the flow rate determination method according to the third embodiment are set as follows: where j is the number of processed wafers W since the QC time, and j=0 indicates the QC time. Also, (*) indicates the number of wafers W processed since the QC time. １ N supplied from ２Gas (L1N), second gas line L ２ N supplied from ２ Gas (L2N) or H ２ gas (L2H). ＊ｉｊ : 　 First gas line L １ N supplied from ２ Gas, second gas line L ２ N supplied from ２ Gas or H ２ Doping sensitivity [cm ] at position i by the flow rate of any (*) gas －３ / sccm] R ｉ : 　　　 Reference deposition rate at position i [μm / sec] Z Ｎｉｊ : 　 Second gas line L ２ N ２ Film formation rate sensitivity at position i due to gas flow rate [μm / sccm / sec] Z Ｈｉｊ : 　 Second gas line L ２ H ２ Film formation rate sensitivity at position i due to gas flow rate [μm / sccm / sec] N Ｌ１ : 　　 During QC, the first gas line L １ N to be supplied from ２ Target gas flow rate [sccm] N Ｌ２ : 　　 During QC, the second gas line L ２ N to be supplied from ２ Target value of gas flow rate [sccm] H: 　　　　 During QC, the second gas line L ２ H to be supplied from ２ Target value of gas flow rate [sccm] τ: 　　　　 Film formation processing time [sec] ΔN Ｌ１ｊ : 　 First gas line L １ N to be supplied from ２ Gas flow rate adjustment amount from QC [sccm] ΔN Ｌ２ｊ : 　 Second gas line L ２ N to be supplied from ２Gas flow rate adjustment amount from QC [sccm] ΔH ｊ : Second gas line L ２ H to be supplied from ２ Gas flow rate adjustment amount from QC [sccm] D ＴＧＴｉ : Target value of doping amount at position i [cm －３ ] T ＴＧＴｉ : Target film thickness at position i [μm] m １ｊ : 　　 Accumulated film thickness from the initial state of the susceptor 20 [μm] m ２ｊ : 　　 Accumulated film thickness from the initial state of the susceptor case 23 [μm] a １＊ｉ : 　 First gas line L １ N supplied from ２ Gas, second gas line L ２ N supplied from ２ Gas or H ２ The coefficient of the ratio of the doping sensitivity to the cumulative film thickness of the susceptor 20 at position i by any of the gases (*) [cm －３ / μm / sccm] a ２＊ｉ : 　 First gas line L １ N supplied from ２ Gas, second gas line L ２ N supplied from ２ Gas or H ２ The coefficient of the ratio of the doping sensitivity to the cumulative film thickness of the susceptor case 23 at position i by any of the gases (*) [cm －３ / μm / sccm]b １＊ｉ : 　 First gas line L １ N supplied from ２ Gas, second gas line L ２ N supplied from ２ Gas or H ２ Reference doping amount [cm 3 ] at position i by any of the gases (*) －３ / sccm]

[0094] In the flow rate determination method according to the third embodiment, first, as in the first and second embodiments, the first gas line L １ and the second gas line L２ The film formation process of the wafer W is repeated, and the doping amount D ｉ (Step St301 in FIG. 15). As a result, the coefficient a １＊ｉ , a ２＊ｉ , and the reference doping amount b １＊ｉ is determined.

[0095] Next, from the following formula (25), the doping sensitivity y ＊ｉｊ is determined (step St302 in FIG. 15).

[0096] D ＴＧＴｉ , T ＴＧＴｉ is the objective variable, and ΔN Ｌ１ｊ , ΔN Ｌ２ｊ , ΔH ｊ are used as explanatory variables, and the following equations (26) and (27) are obtained as the relational expressions that these must satisfy.

[0097] Next, N at time QC+j is calculated by an optimization method so as to satisfy the above equations (26) and (27). ２ Adjustment amount ΔN of the target value of the gas flow rate Ｌ１ｊ , ΔN Ｌ２ｊ , and 、 Second gas line L ２ H supplied from ２ Adjustment amount ΔH of the target value of the gas flow rate ｊ (Step St303 in FIG. 15). As an optimization method, for example, the least squares method may be used. In this case, as in the second embodiment, first, N ２ Target gas flow rate N Ｌ１ , N Ｌ２ and H ２ The target value H of the gas flow rate may be determined, and then the above adjustment amount for any j may be determined.

[0098] According to the flow rate determination method of the third embodiment, in addition to the effects described in the first and second embodiments, the second gas line L ２ H supplied from ２The gas flow rate can be optimized, thereby simultaneously optimizing both the doping amount distribution and the film thickness distribution within the surface of the wafer W.

[0099] Furthermore, when the gas supply mechanism 15 according to one embodiment has a configuration for supplying another gas that affects both the doping amount distribution and the film thickness distribution within the surface of the wafer W, the flow rate determination method according to the third embodiment can be applied to that gas, thereby making it possible to simultaneously optimize both the doping amount distribution and the film thickness distribution for that gas.

[0100] Fourth Embodiment Next, as a fourth embodiment of the present disclosure, a method for determining a coefficient of the ratio of doping sensitivity to cumulative film thickness, which is applicable to the techniques of the present disclosure including the first to third embodiments, will be described.

[0101] As illustrated in the first to third embodiments, the doping sensitivity y ｉ A linear regression model can be considered with y as the objective variable and the cumulative film thickness x on the susceptor 20 as the explanatory variable (y ｉ = a ｉ x + b ｉ ). The coefficient a in such a regression equation ｉ is considered to be a quantitative index that characterizes the memory effect. ｉ are the coefficients a and a in the first to third embodiments. １ｉ , a ２ｉ and a １＊ｉ The doping sensitivity y ｉ When calculating the coefficients a for the first gas line L1 and the second gas line L2, ｉ can be determined for each of the first gas line L1 and the second gas line L2.

[0102] In steps St101, St201, and St301 of the first to third embodiments, the coefficient a ｉ The coefficient a obtained in the steps illustrated in the first to third embodiments can be calculated. ｉcan be used as a fixed value in the subsequent steps in each embodiment. ｉ The flow rate for successively processing a plurality of wafers W (for example, j wafers W in the second and third embodiments) is determined using the coefficient a ｉ The flow rate for processing the next set of wafers W can be determined using the coefficient a ｉ The value of is the coefficient a in the same step when another susceptor 20 is used. ｉ can be reused and used as the value of

[0103] As a result of intensive research by the present inventors, it was found that this coefficient a ｉ It has been found that this may depend on the individual differences of the susceptor 20 used.

[0104] Therefore, in this embodiment, the coefficient a ｉ is not used as a fixed value, but the coefficient a is calculated based on past data before determining the flow rate. ｉ This allows a flow rate to be determined that fully reflects the memory effect, even when multiple wafers W are processed consecutively, and makes it possible to achieve a more preferable distribution of the doping concentration of the wafers W.

[0105] In this embodiment, as shown in FIG. 16 , a flow rate is determined during QC, and a predetermined number of wafers W are processed consecutively (hereinafter referred to as a “consecutive run”), thereby processing multiple wafers W. A continuous run corresponds to a set of j wafers W processed in the second and third embodiments, for example. That is, in one continuous run, a flow rate for each wafer W to be processed in the continuous run is determined first during QC. However, multiple continuous runs described below are performed using the same susceptor 20, and this susceptor 20 is referred to as the “current susceptor.” Furthermore, a susceptor 20 that was used before the current susceptor is referred to as the “previous susceptor.”

[0106] 16 is a flowchart showing an outline of a configuration example of a method for determining a flow rate and performing processing according to this embodiment. First, in processing using a current susceptor, the coefficient a ｉ is determined (step St401 in FIG. 16). ｉ A detailed example of a method for determining the coefficient a will be described later. ｉ Using the flow rate, the flow rate for each wafer W to be processed in the subsequent continuous run is determined (step St402 in FIG. 16). The determination of the flow rate in step St402 can be performed, for example, in the same manner as in the first to third embodiments. Then, the continuous run is performed using the determined flow rate (step St403 in FIG. 16). Then, it is determined whether to end the film formation process. If the film formation process is not to be ended, the next continuous run is performed, and the process returns to step St401. If the film formation process is to be ended, the method ends.

[0107] In step St401, a coefficient a related to the memory effect is calculated using learning data acquired by measurements after a plurality of past processes (runs) performed using the current susceptor. ｉ In one embodiment, the coefficient a ｉ The determination of coefficient a can be performed as shown in Figure 17. Figure 17 shows the coefficient a according to one embodiment. ｉ 10 is a flowchart showing an outline of a configuration example of a method for determining the number of times ...

[0108] First, as a premise, for example, a doping concentration at an arbitrary position i on the surface of the wafer W, a cumulative film thickness x during the process, and N used in the process are obtained by a plurality of past film forming processes. ２ Coefficient a based on multiple data including gas flow rate ｉ The prior distribution of the coefficient a ｉThe prior distribution may be acquired based on the data for past susceptors in addition to the data for the current susceptor. The prior distribution acquired in this manner may be stored in the control unit 100, for example, and read out in a desired process. Note that the prior distribution is not limited to data from past production, and may be acquired based on data from trials using dummy wafers or data obtained by simulation.

[0109] Furthermore, by performing post-processing measurements of a plurality of past processes (runs) performed using the current susceptor, the doping concentration at an arbitrary position i on the surface of the wafer W, the cumulative film thickness x during the process, and the N ２ Coefficient a based on data including gas flow rate ｉ The learning data is acquired in advance. The learning data may be acquired by measuring a plurality of wafers W processed in a continuous run after the execution of the above-mentioned step St403. Note that there is no data of past processing in the continuous run immediately after the susceptor 20 is replaced with the current susceptor. Therefore, after the susceptor 20 is replaced, the coefficient a can be calculated by performing processing for quality control several times. ｉ The learning data of the coefficient a ｉ The learning data may be stored in the control unit 100, for example, and read out in a desired process.

[0110] Coefficient a ｉ In the method of determining the coefficient a ｉ The prior distribution of the coefficient a ｉ The learning data of is read out (step St412 in FIG. 17). Then, the coefficient a is calculated from the prior distribution and the learning data. ｉ The posterior distribution of the coefficient a is calculated (step St413 in FIG. 17). ｉ When calculating the posterior distribution of , for example, Bayesian estimation can be used.

[0111] In one embodiment, the coefficient a read out in step St411 ｉ The prior distribution of the coefficient a ｉand the coefficient a calculated in step St413 in the consecutive run immediately preceding the consecutive run for which the flow rate is to be determined (hereinafter referred to as the "current run"). ｉ In other words, the coefficient a in the consecutive run immediately before the current run (one run before) may be a posterior distribution of ｉ The posterior distribution of may be used as the prior distribution for the current run.

[0112] In one embodiment, the learning data read in step St412 may be learning data acquired after the consecutive run two runs before the current run. That is, acquiring learning data after the consecutive run one run before the current run requires time for measurement, and therefore a waiting time may be required before the learning data can be used in the current run. In contrast, measurement of the learning data after the consecutive run two runs before the current run has already been completed by the time step St412 related to the current run is executed, and therefore the waiting time is not considered to be required.

[0113] The inventors used the method according to this embodiment to calculate the coefficient a ｉ By updating and determining the coefficient a ｉ It was confirmed that the accuracy index of doping concentration control was further improved compared to when using a fixed value. As an example of the accuracy index, the number of rejected wafers W including portions where the doping concentration was outside the reference value range was reduced by approximately 40%. Furthermore, the average concentration error within the surface of the wafer W was reduced (improved) by approximately 32%. Furthermore, the concentration error variation within the surface of the wafer W was reduced (improved) by approximately 23%.

[0114] Although the above description has been given of the case where the cumulative film thickness x of the susceptor 20 is used as the explanatory variable, the coefficients of the regression equation can be determined in the same main steps even when the cumulative film thickness of the susceptor case 23 is included as an explanatory variable. In one embodiment, when the cumulative film thickness of the susceptor case 23 is included as an explanatory variable in the regression equation, the data set in the prior distribution of the Bayesian estimation may include long-term data including processing results of a plurality of susceptor cases 23 from their initial states to cleaning or replacement.

[0115] The regression equation is not limited to the linear equation described above, and the dope sensitivity y can be calculated using a quadratic or higher regression equation.ｉ The same applies to the case where the coefficients of each order of the cumulative film thickness x are calculated when

[0116] Also, in the above, coefficient a ｉ As an example of a method for determining the posterior distribution, a is determined by Bayesian estimation using the prior distribution and learning data for the current susceptor. However, the technology of the present disclosure is not limited to this. For example, the coefficient a determined in a consecutive run prior to the current run may be used. ｉ The coefficient a of the current run is calculated by a desired known feedback method using ｉ may be determined.

[0117] In addition, when multiple consecutive runs are repeatedly performed, the coefficient a ｉ Instead of determining the coefficient a for each desired number of consecutive runs, ｉ may be updated and determined.

[0118] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The above-described embodiments may be omitted, substituted, or modified in various ways without departing from the scope and spirit of the appended claims. For example, the components of the above-described embodiments may be arbitrarily combined. Such an arbitrary combination naturally provides the functions and effects of each of the components involved in the combination, and also provides other functions and effects that are apparent to those skilled in the art from the description of this specification.

[0119] Furthermore, the effects described in this specification are merely descriptive or exemplary and are not limiting. In other words, the technology according to the present disclosure may achieve other effects that are apparent to those skilled in the art from the description of this specification, in addition to or in place of the above-described effects.

[0120] 1 Film forming device 16 Injector 16h １　 1st supply port 16h ２　 Second supply port 100 Control unit BP Byproduct L １　　 First gas line L ２　　 Second gas line W Wafer S Processing space

Claims

1. A substrate processing apparatus for processing a substrate with a gas, comprising: an injector having a supply port for introducing the gas into a processing space for processing the substrate; a first gas line and a second gas line for supplying the gas to the injector; and a control unit, wherein the supply ports include a first supply port formed in a portion other than a central portion of the injector and a second supply port formed in the central portion of the injector, the gas supplied from the first gas line to the injector is configured to be supplied to the processing space from the first supply port, and the gas supplied from the second gas line to the injector is configured to be supplied to the processing space from the second supply port, and the control unit performs control including determining a first flow rate of the gas to be supplied from the first gas line and a second flow rate of the gas to be supplied from the second gas line based on a memory effect caused by by-products adhering to surfaces of components in the processing space.

2. The substrate processing apparatus according to claim 1, wherein the components within the processing space include either or both of a susceptor on which the substrate is placed and a susceptor case in which the susceptor is housed and the processing space is defined inside.

3. The substrate processing apparatus according to claim 1, wherein the injector is configured such that the longitudinal direction in which the plurality of supply ports are provided is parallel to the substrate, and the gas is introduced from the side of the substrate.

4. The substrate processing apparatus according to claim 1, further comprising a flow rate controller configured to be able to individually control the flow rates of the gases supplied from the first gas line and the second gas line.

5. The gas supplied from the second gas line is N ２ Gas and H ２ The substrate processing apparatus according to claim 1 , further comprising a gas, wherein the control unit executes control that includes adjusting a thickness of a film formed on the substrate by the gas.

6. The gas supplied from the first gas line is N ２ the gas supplied from the second gas line includes N ２ The substrate processing apparatus according to claim 1 , further comprising a gas, wherein the control unit executes control that includes adjusting a doping amount of nitrogen in a film formed on the substrate by the gas.

7. In determining the first flow rate and the second flow rate, the control unit ２ a first sensitivity to the doping amount by the gas and a N ２ and a second sensitivity to the doping amount by the gas for each position within the surface of the substrate.

8. The substrate processing apparatus according to claim 7, wherein the control unit performs control including determining the first flow rate and the second flow rate by an optimization method with constraints based on the first sensitivity and the second sensitivity.

9. The substrate processing apparatus of claim 7 or 8, wherein the component in the processing space includes a susceptor on which the substrate is placed, and when the cumulative film thickness is defined as the integrated value of the thickness of the film formed on each substrate when processing a plurality of the substrates from when the susceptor is in an initial state, the control unit determines coefficients of the ratios of the first sensitivity and the second sensitivity to the cumulative film thickness, respectively, before determining the first flow rate and the second flow rate.

10. The substrate processing apparatus according to claim 9, wherein the control unit performs control including repeating successive runs including: determining the coefficient; determining the first flow rate and the second flow rate using the coefficient; and processing a plurality of the substrates using the first flow rate and the second flow rate.

11. The substrate processing apparatus according to claim 10, wherein the control unit executes control in determining the coefficients, including determining a posterior distribution of the coefficients from a pre-acquired prior distribution of the coefficients and pre-acquired learning data.

12. The substrate processing apparatus according to claim 11, wherein the learning data is obtained by measuring a plurality of substrates after past processing on the susceptor currently in use.

13. The substrate processing apparatus of claim 12, wherein the learning data is obtained by measurement after processing of the substrate in the consecutive runs two runs prior to the consecutive runs from which the coefficients, the first flow rate, and the second flow rate are to be determined, using the susceptor currently in use.

14. The control unit is configured to: ２ 7. The substrate processing apparatus according to claim 6, wherein the apparatus performs control including: calculating a reference doping amount, which is the doping amount per unit gas flow rate; performing a first process for processing the substrate based on the determined first flow rate and the determined second flow rate; correcting the reference doping amount in a second process performed after the first process; and determining the first flow rate and the second flow rate based on the corrected reference doping amount.

15. The control unit, in determining the first flow rate and the second flow rate, ２ 8. The substrate processing apparatus according to claim 7, wherein the control includes: calculating a third sensitivity to the doping amount by the gas for each position within the surface of the substrate; and determining the first flow rate and the second flow rate by an optimization method with constraints based on the first sensitivity, the second sensitivity, and the third sensitivity so that the film thickness of the film formed on the substrate and the doping amount are simultaneously optimized.

16. A substrate processing method for processing a substrate with a gas using a substrate processing apparatus, the substrate processing apparatus comprising: an injector having a supply port for introducing the gas into a processing space in which the substrate is processed; and a first gas line and a second gas line for supplying the gas to the injector, the supply ports including a first supply port formed in a portion other than a central portion of the injector and a second supply port formed in the central portion of the injector, the gas supplied from the first gas line being configured to be introduced into the processing space from the first supply port, and the gas supplied from the second gas line being configured to be introduced into the processing space from the second supply port, the substrate processing method comprising determining a first flow rate of the gas to be supplied from the first gas line and a second flow rate of the gas to be supplied from the second gas line based on a memory effect caused by a by-product adhering to a surface of a component in the processing space.

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