Information processing method and substrate processing device

Abstract

This information processing method includes: obtaining an estimated distribution of doping concentrations for a verification process set by using a plurality of items of preliminary data that are measurement results for doping concentrations of a plurality of substrates processed in a preliminary process set that is a set of a plurality of past deposition processes in a deposition device, and a plurality of items of verification data that are measurement results for doping concentrations of a plurality of substrates processed in the verification process set that is a set of a plurality of deposition processes of interest in the deposition device; acquiring the difference between the estimated distribution and measurement results for doping concentrations of a substrate processed in a verification run that is a set of deposition processes of interest in the verification process set; and determining that the measurement results for the verification run of interest are abnormal when the difference exceeds a predetermined threshold.

Description

Information processing method and substrate processing apparatus

[0001] This disclosure relates to an information processing method and a substrate processing apparatus.

[0002] Patent Document 1 discloses a film deposition apparatus for depositing a SiC film on a silicon carbide (SiC) substrate. The film deposition apparatus includes a mounting table on which the SiC substrate is placed, a gas supply mechanism configured to form a flow of raw material gas from outside 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 described herein enables appropriate film deposition processing in a substrate processing apparatus.

[0005] One aspect of the present disclosure is an information processing method comprising: using a plurality of pre-data, which are measurement results of the dope concentrations of a plurality of substrates processed in a pre-processing set, which is a set of a plurality of past film deposition processes in a film deposition apparatus, and a plurality of verification data, which are measurement results of the dope concentrations of a plurality of substrates processed in a verification processing set, which is a set of a plurality of film deposition processes of interest in the film deposition apparatus, to obtain an estimated distribution of the dope concentrations for the verification processing set; obtaining the difference between the estimated distribution and the measurement results of the dope concentrations of substrates processed in a verification run, which is a film deposition process of interest in the verification processing set; and determining that the measurement results of the verification run of interest are abnormal if the difference exceeds a predetermined threshold.

[0006] According to this disclosure, film deposition processing can be performed appropriately in a substrate processing apparatus.

[0007] This is a diagram showing the schematic configuration of the film deposition apparatus according to the embodiment. This is a cross-sectional view showing the schematic configuration of the processing container of the film deposition apparatus according to the embodiment. This is a diagram showing the schematic configuration of the injector according to the embodiment. This is a flowchart showing an example of the configuration of the main steps of the film deposition method according to the embodiment. This is a schematic diagram for explaining the memory effect. This is a schematic diagram for explaining the memory effect. This is a schematic diagram for explaining the memory effect. This is a schematic plan view showing the schematic of gas supply to the wafer and the schematic of measurement points. This is a flowchart showing an example of the configuration of the main steps of the flow rate determination method according to the embodiment. This is a graph showing the Bayesian model and the schematic of the measurement results during QC. This is a graph showing the schematic of the measurement results during QC when part of the measurement results are replaced.

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

[0009] <Film Deposition Apparatus> Figure 1 is a schematic diagram of the configuration of a film deposition apparatus 1 as a substrate processing apparatus according to this embodiment. The film deposition apparatus 1 includes a processing container 11 that is roughly rectangular in shape. An exhaust line 12 is connected to the processing container 11, and the processing container 11 can be adjusted to a predetermined reduced pressure state (pressure) by the exhaust line 12. The exhaust line 12 has an exhaust pipe 12a, one end of which is connected to the processing container 11. The exhaust pipe 12a consists of an exhaust manifold or the like, and a vacuum pump 12b, consisting of a mechanical booster pump or the like, is connected to the opposite side from the processing container. Between the processing container 11 and the vacuum pump 12b in the exhaust pipe 12a, a pressure adjustment unit 12c is provided, consisting of an APC (Automatic Pressure Control) valve or a proportional control valve, for adjusting the pressure inside the processing container 11. In addition, a pressure gauge 13 is provided in the processing container 11, and the pressure adjustment inside the processing container 11 by the pressure adjustment unit 12c is performed based on the measurement result from the pressure gauge 13.

[0010] The processing container 11 has a hollow rectangular columnar processing container body 11a having openings at both ends, and side wall portions 11b connected to both ends of the processing container body 11a so as to close the openings. The processing container 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 supply 14a is provided outside the processing container body 11a. The induction coil 14 heats the substrate to be processed. For example, it inductively heats a susceptor case 23 described later, and heats the substrate to be processed by the radiant heat from the inductively heated susceptor case 23.

[0012] In the processing container 11, a raw material gas or the like that is a raw material for film formation is configured to be supplied by a gas supply mechanism 15. The gas supply mechanism 15 is connected to an injector 16 provided in the processing container 11, which will be described later. The gas supply mechanism 15 has a first gas line L １ and a second gas line L ２ . The first gas line L １ and the second gas line L ２ are respectively connected to a first supply pipe 15a １ and a second supply pipe 15a ２ connected to the injector 16, and a supply pipe 15b １ connected to the first and second supply pipes 15a ２ and 15a １１ ~15b １６ and 15b ２１ ~15b ２２ .

[0013] The supply pipes 15b １１ ~15b １６ and 15b ２１ ~15b ２２ are respectively provided with a mass flow controller (MFC) 15c １１ ~15c １６ and a valve 15d ２１ ~15d ２２ and 15d １１ ~15d １６ ~15d ２１ ~15d ２２ as a flow rate controller.

[0014] First gas line L １ In this case, the supply pipe 15b １１ The supply source 15e １１ The supply source 15e is connected to it. １１ From N ２ Gas is supplied. Similarly, supply pipe 15b １２ ~15b １６ Each of these is a supply source 15e １２ ~15e １６ The following 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 this case, the supply pipe 15b ２１ The supply source 15e ２１ The supply source 15e is connected to it. ２１ From N ２ Gas is supplied. Similarly, supply pipe 15b ２２ The supply source 15e ２２ H is connected ２ Gas is supplied.

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

[0017] In one embodiment, another gas line (not shown) is provided to supply another single gas or mixed gas (not shown) to the injector 16. This other gas line is, for example, C ２ H ２ Gas, C ２ H ４ Gas, or C ２ H ６ It has other sources (not shown) that supply one of the gases.

[0018] When forming an n-type SiC film on a SiC substrate as the substrate to be processed by epitaxial growth, the raw material gas for film formation is supplied by the gas supply pipe 15b. １ ~15b ５ From SiH ４ Gas, C ３ H ８ Gas, H ２ Gas, N ２ Gas and HCl gas are supplied to the processing container 11. A gas supply source and gas supply pipes for TMA (trimethylaluminum) gas may also be provided for the formation of p-type SiC films.

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

[0020] The film deposition apparatus 1 described above is provided with at least one control unit 100, as shown in Figure 1. The control unit 100 processes computer-executable instructions that cause the film deposition apparatus 1 to perform various processes described herein, such as a flow rate determination method or an information processing method. The control unit 100 may be configured to control each element of the film deposition 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 deposition apparatus 1. The control unit 100 is implemented, for example, by a computer. The control unit 100 may be one or more circuits, and may be provided as a single unit or in parts. The control unit 100 may include a processing unit, a storage unit, and a communication interface. The functions realized by the processing units described in this disclosure may be implemented in circuits or processing circuits, including general-purpose processors, application-specific processors, integrated circuits, ASICs (Application Specific Integrated Circuits), CPUs (Central Processing Units), conventional circuits, and / or combinations thereof, programmed to realize the functions described. A processor is considered to be a circuit or processing circuit, including transistors and other circuits. A processor may be a programmed processor that executes a program stored in memory. This program (computer program product) may be stored in memory beforehand or may be retrieved via a medium when needed. The medium may be various computer-readable storage media, such as memory cards, optical discs, HDDs (Hard Disk Drives), or other removable storage media, and the program may be provided in a form stored on such storage media. Alternatively, the medium may be a communication line connected to a 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 read from the storage unit and executed by the processing unit.The memory unit may include storage media such as RAM (Random Access Memory), ROM (Read Only Memory), EEPROM (Electronically Erasable Programmable Read Only Memory), HDD (Hard Disk Drive), SSD (Solid State Drive), or combinations thereof. The communication interface may communicate with the substrate processing device 1 via a communication line such as a LAN (Local Area Network). In this disclosure, circuits, units, and means are hardware programmed to realize or configured to perform the described functions. Such hardware may be any hardware described in this disclosure, or any hardware known to be programmed to realize or perform such functions. If the hardware is a processor that is considered to be a type of circuit, then the circuit, means, or unit is a combination of hardware and software used to constitute the hardware and / or processor.

[0021] The information processing method disclosed herein may be executed by a device including a desired computer located outside the film deposition apparatus 1, which is different from the control unit 100 provided in the film deposition apparatus 1. Such a desired computer device may have the same configuration as the control unit 100.

[0022] <Processing Container> Next, the configuration inside the processing container 11 will be described. Figure 2 is a schematic cross-sectional view showing the general configuration inside the processing container 11 in the film deposition apparatus 1 of Figure 1. Inside the processing container 11, as shown in Figure 2, there is a susceptor 20 on which a SiC substrate (hereinafter referred to as wafer W) as a substrate to be processed is placed via a holder H, a rotating shaft 21 that rotates the susceptor 20 and supports the susceptor 20, and a lifting unit 22 that raises and lowers the holder H on which the wafer W is placed. In addition, a susceptor case 23 is provided inside the processing container 11 as a housing unit, and 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.

[0023] The susceptor 20 is formed in the shape of a disc with a recess 20a on its upper surface that is recessed vertically downward, and is installed horizontally inside the processing container 11. The holder H is fitted into the recess 20a. The holder H is rotated by the rotation shaft 21 around the central axis P of the susceptor 20 and the rotation shaft 21, and the holder H is rotated as well.

[0024] Furthermore, the susceptor 20 is made of a conductive material that has high heat resistance and is easily heated by induction heating, and is composed of, for example, a graphite member whose upper surface is coated with SiC.

[0025] The holder H has a mounting area Ha formed on its upper surface on which the wafer W is placed. The holder H is made of a conductive material that has high heat resistance and is easily heated by induction heating, and is made of a graphite member whose upper surface on which the wafer W is mounted is coated with SiC. The holder H is formed in a disc shape with a smaller diameter than the susceptor 20, for example.

[0026] One end of the rotating shaft 21 is connected to the lower center of the susceptor 20, and the other end extends through the bottom of the processing container 11 to its lower side and is connected to a rotary drive mechanism (not shown). The rotation of the rotating shaft 21 by the rotary drive mechanism causes the susceptor 20 to rotate.

[0027] The lifting unit 22 is used to transfer the wafer W between the wafer W transport device outside the film deposition apparatus 1 and the susceptor 20, and in this example, it 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.

[0028] The susceptor case 23 is formed in the shape of a rectangular parallelepiped with openings on two opposing sides, and the processing gas is supplied from the opening on one side and discharged from the opening on the other side. In this structure, the processing gas supplied onto the wafer W is supplied and discharged along a direction parallel to the wafer W, which is perpendicular to the central axis P.

[0029] The susceptor case 23 is made of a conductive material that has high heat resistance and is easily heated by induction heating. For example, it is made of a graphite component with the wafer W-side surface coated with SiC.

[0030] Furthermore, an insulating material 24 is provided on the outer circumference of the susceptor case 23 to insulate the susceptor case 23 from the processing container 11. The insulating material 24 is formed, for example, using a fibrous carbon material with a high porosity. Although not shown in the figures, a holding structure is provided on the outside of the insulating material 24 to hold the insulating material 24 in a state where it is separated from the processing container 11.

[0031] Figure 3 is a schematic diagram 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. In addition, the side portion 16s of the injector 16 facing the processing space S has multiple supply ports, the first supply ports 16h. １ and second supply port 16h ２ A 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 ２The gases supplied from [the source] are respectively introduced into the processing space S. In one embodiment, inside the injector 16, there is a first gas line L １ and a second gas line L ２ configured to distribute the gases supplied from [the source] to each supply port 16h １ 、16h ２ is provided with a diffusion space.

[0032] The first supply port 16h １ is configured to introduce the gas supplied from the first gas line L １ into the processing space S. The first supply port 16h １ is formed at substantially equal intervals in the width direction of the side surface portion 16s excluding the central portion in the width direction of the side surface portion 16s where the second supply port 16h ２ is formed. In one embodiment, when other gas lines are provided, a plurality of other supply ports (not shown) for introducing the gas supplied from the gas line may be formed alternately with the plurality of supply ports 16h １ .

[0033] The second supply port 16h ２ is configured to introduce the gas supplied from the second gas line L ２ into the processing space S. The supply port 16h ２ is formed only at the central portion in the width direction of the side surface portion 16s. In one embodiment, the second supply port 16h ２ is formed in plurality near the central portion in the width direction of the side surface portion 16s.

[0034] <Film Formation Method> Next, a film formation method as a substrate processing method using the film formation apparatus 1 will be described. FIG. 4 is a flowchart showing an outline of a configuration example of the film formation method according to the present embodiment.

[0035] First, a holder H on which a wafer W is placed is carried into the processing container 11 (step St1 in FIG. 4). Specifically, the holder H is carried into the processing container 11 from the outside of the film forming apparatus 1 via a gate valve (not shown) using a transfer means (not shown) outside the film forming apparatus 1, and is positioned above the susceptor 20. Next, the elevating part 22 is raised, and the holder H is supported by the elevating part 22. Then, the transfer means is retracted from the inside of the processing container 11, and the elevating part 22 is lowered to place the holder H on the susceptor 20.

[0036] After the holder H is carried in, a raw material gas and a carrier gas are supplied from the gas supply mechanism 15 through the injector 16 in a direction orthogonal to the central axis P in the processing container 11. Along with the gas supply, high-frequency power is applied from the high-frequency power supply 14a to the induction coil 14 to heat the wafer W, and an n-type SiC film is formed on the wafer W by epitaxial growth (step St2 in FIG. 4).

[0037] In step St2, in the first gas line L １ the valves 15d １１ to 15d １５ are opened, and the flow rates are adjusted by the MFCs 15c １１ to 15c １５ to supply N ２ gas, H ２ gas, SiH ４ gas, C ３ H ８ gas, and HCl gas into the processing container 11. Also, in the second gas line L ２ the valves 15d ２１ to 15d ２２ are opened, and the flow rates are adjusted by the MFCs 15c ２１ to 15c ２２ to supply N ２ gas and H ２ gas into the processing container 11. At this time, the flow rates of the gases supplied from the respective gas lines L １ , L ２ are set to target flow rates determined in advance by the method described later.

[0038] In step St2, high-frequency power is applied to the induction coil 14 from the high-frequency power supply 14a, thereby heating the wafer W through radiation and heat conduction from the induction-heated holder H, susceptor 20, and susceptor case 23. During film deposition, the pressure inside the processing container 11 is, for example, 10 Torr to 600 Torr, and the temperature of the wafer W is, for example, 1500°C to 1700°C.

[0039] After the film deposition is complete, the holder H supporting the wafer W is removed from the processing container 11 (step S3). Specifically, valve 15d １ ~15d ５ After closing the valve and stopping the supply of raw material gas and carrier gas, the lifting unit 22 is raised to raise the holder H that supports the wafer W. Then, the transport means outside the film deposition apparatus 1 is inserted into the processing container 11 via the gate valve and positioned below the holder H. After that, the lifting unit 22 is lowered to transfer the holder H from the lifting unit 22 to the transport means, and the transport means is moved out of the processing container 11, thereby removing the holder H that holds the wafer W from the processing container 11. Note that the supply of high-frequency power to the induction coil 14 may be cut off during the removal of the wafer W, but it is preferable to supply high-frequency power to the induction coil 14 while controlling the temperature so that the susceptor 20 and susceptor case 23 reach the optimal temperature in the next process.

[0040] After removing holder H, the process may be returned to step S1, another holder H with another wafer W placed on it may be brought into the processing container 11, and the process from step St1 to step St3 may be repeated.

[0041] <Flow Rate Determination Method> The method for determining the flow rate of the gas supplied in step St2 described above will be explained below. The flow rate determination method according to this embodiment includes the information processing method of the disclosure. Figures 5 to 7 are diagrams for explaining the memory effect. Figure 8 shows the first gas line L １ and the second gas line L ２ This is a schematic plan view showing the general flow of gas supply to wafer W from both sides. Figure 9 is a schematic flowchart of an example configuration of the flow rate determination method according to this embodiment.

[0042] First, in a conventional film deposition process using a conventional film deposition apparatus, the memory effect when a SiC film is deposited on a wafer W by epitaxial growth in step St2 above will be explained using Figures 5 to 7.

[0043] Figure 5(a) shows the initial state, for example, immediately after the susceptor 20 has been replaced or cleaned. In the initial state, no byproduct BP is attached to the surface of the susceptor 20. Figure 5(b) shows the state after the same film deposition process as St2 has been repeated multiple times from the state in Figure 5(a), and Figure 5(c) shows the state after the film deposition process has been repeated multiple times further from the state in Figure 5(b). As shown in Figures 5(b) and (c), when the film deposition of St2 is repeated in the substrate processing, N ２ Byproduct BP containing may accumulate. Furthermore, the amount of such byproduct BP increases with the number of repeated film deposition cycles. When a wafer W is placed on a susceptor 20 in a state where byproduct BP has accumulated and substrate processing is performed, the H supplied during film deposition may accumulate. ２ A portion of the byproduct BP is etched by the gas. During this process, nitrogen atoms N are released from the byproduct BP and doped into the SiC film of the wafer W near the byproduct BP. As a result, the amount of nitrogen doped into a certain portion of the SiC film on the wafer W (hereinafter simply referred to as "doping amount") is determined by the amount of N supplied by St2. ２ The doping level may exceed the expected level due to the gas. This effect of increased doping due to the accumulation of by-product BP during repeated film deposition is called the memory effect.

[0044] As shown in Figure 6, byproduct BP accumulates on the surface of the susceptor 20 and the surface of the susceptor case 23. Furthermore, H etches the byproduct BP. ２Since the gas is supplied from the injector 16 and the wafer W is rotated by the rotation axis 21 during film deposition, the SiC film is more heavily doped at the peripheral edge E of the wafer W near the injector 16. In Figure 7, areas with relatively high doping are shown with dark shading, and areas with relatively low doping are shown with light shading. As shown in Figure 7, due to the memory effect, the peripheral edge E of the wafer W is more heavily doped than the central part C. Furthermore, the increase in doping at the peripheral edge E becomes more pronounced with increasing number of film deposition cycles due to the memory effect.

[0045] In the flow rate determination method according to this embodiment, the first gas line L takes into consideration the memory effect described above. １ and the second gas line L ２ The flow rate of the gas to be supplied (hereinafter referred to as the "target flow rate") is determined. Specifically, during the film deposition process of a desired number of wafers W (hereinafter referred to simply as "QC time" as quality control time), the dope concentration of the wafers W processed during QC time is measured, and the target flow rate for subsequent wafers W is determined based on the dope concentration. In this embodiment, the measurement of the dope concentration is performed, as an example, at a desired number of measurement points (P1, P2, ...) in the radial direction from the center C to the peripheral E of the wafer W, as shown in Figure 8. However, the position and number of measurement points are not limited to this, and the position and number of measurement points can be set to any desired position and number based on the required accuracy of the target flow rate, etc.

[0046] According to the film deposition apparatus 1 of the above embodiment, the target flow rate can be determined independently for the first gas line and the second gas line. As shown in Figure 8, the first gas line can supply gas to the entire width of the wafer W, while the second gas line can supply gas mainly to the center C of the wafer W. By determining the target flow rate for each of the first and second gas lines, taking into account the radial bias in dope concentration due to the memory effect, the distribution of dope concentration in the plane of the wafer W can be brought closer to the desired one.

[0047] In determining the target flow rate, the inventors conducted thorough research and found that when the next wafer W was subjected to film deposition using the target flow rate determined based on the dope concentration, the distribution of dope concentration within the surface of the wafer W may not be as desired. Further investigation by the inventors into such cases revealed that, during the measurement of the dope concentration of the wafer W processed during QC, the dope concentration at any measurement point in the radial direction of the wafer W may have been obtained as an incorrect value due to measurement anomalies or other reasons.

[0048] In view of the above problems, the present inventors conceived of detecting an anomaly in the measurement result when the dope concentration is obtained as an incorrect value in the measurement result after a certain run, and came up with the flow rate determination method according to the present embodiment.

[0049] Specifically, first, multiple sets of preliminary data are acquired (step St101 in Figure 9). The multiple sets of preliminary data acquired in step St101 are, for example, a dataset of the coordinates x (radial position of the wafer W) of multiple measurement points and the dope concentration y at each of those measurement points (see Figure 10). The multiple sets of preliminary data are, for example, multiple measurement results of dope concentrations after multiple past runs.

[0050] The pre-data according to this embodiment is obtained from a set of runs (hereinafter referred to as "processing sets") executed in a processing container 11 from the initial state of a certain susceptor 20 until it is replaced with the next susceptor 20. Preferably, the pre-data is obtained from the processing set of the susceptor 20 that was used immediately before the processing set of the susceptor 20 being used at the time when the target flow rate is to be determined by the flow rate determination method according to this embodiment. This makes it possible to reduce the influence of memory effects other than those related to the susceptor 20 in the processing container 11, such as memory effects related to the susceptor case 23.

[0051] In the following description, the set of processing steps in the susceptor 20 for which the target flow rate is to be determined by the flow rate determination method according to this embodiment will be referred to as the "verification processing set," and one film deposition process in the verification processing set will be referred to as the "verification run." Furthermore, the processing set preceding the verification processing set for which prior data has been acquired will be referred to as the "pre-processing set," and one film deposition process in the pre-processing set will be referred to as the "pre-run."

[0052] Each of the multiple pre-run data sets, for example, is measured and acquired after the execution of a pre-run, and is stored in the control unit 100.

[0053] The acquisition of prior data is not limited to the above example; it may also be based on prior data acquired for a different processing container 11 than the processing container 11 on which the verification run is performed. Furthermore, prior data acquired for multiple processing sets, rather than just one processing set in processing container 11, may be used as the prior data for process St 101.

[0054] Next, a verification run is performed to acquire multiple verification data (step St102 in Figure 9). The verification run is performed multiple times. In each verification run, the target flow rate is first determined, and the wafer W is processed using the above-described film deposition method with this target flow rate. In this case, the corrected target flow rate can be used in the repeated processing described later.

[0055] After each verification run, verification data is acquired by measuring the dope concentration in the plane of the wafer W, and this verification data is stored, for example, in the control unit 100. The multiple verification data acquired in step St102 are, like the prior data, a dataset of the coordinates x (radial position of the wafer W) of multiple measurement points and the dope concentration y at each of those measurement points (see Figure 10).

[0056] Next, the posterior distribution of the linear regression coefficients is calculated from the prior and validation data based on Bayes' theorem, and the Bayesian estimate is determined (step St103 in Figure 9). In step St103 according to one embodiment, assuming that the linear regression coefficients follow a multivariate normal distribution, the posterior distribution is calculated as follows.

[0057] First, the distribution of linear regression coefficients is determined for multiple pre-processed data obtained in the pre-processing set. The linear regression coefficient is the coefficient vector a, expressed by equation (2) below, when the multiple regression equation for the radial position of wafer W (x; explanatory variable) and dope concentration (y; dependent variable) is set as shown in equation (1) below.

[0058] While not limited to this, when considering multiple regression using equation (1) above for measurement results as shown in Figure 10, the degree of x can be modeled as, for example, 3rd order or higher. The degree of x may also be determined in advance by calculating the fitting accuracy using prior data.

[0059] In this embodiment, the average value (y-bar) of the dope concentration at each radial position of the wafer W is calculated from multiple prior data, and the following equation (3) is obtained from this average value and equation (1) above. Also, the coefficient vector μ as the average of the prior distribution. ０ We obtain the following equation (4) for this.

[0060] Also, the covariance of the prior distribution Σ ０ Set to the desired value. In one embodiment, the standard deviation corresponding to each variance of the prior distribution can be easily calculated as 1 / 10 of the mean of the prior distribution obtained above. In another embodiment, the covariance of the prior distribution can be precisely calculated by obtaining the coefficient vector for each of the multiple prior data using the above formula (1).

[0061] Assuming that the linear regression coefficients follow a multivariate normal distribution, we obtain equation (5) below.

[0062] Next, we have a dataset of n validation data D { (x １ , y １ ), ..., (x ｎ , y ｎ For ), the design matrix G and the dope concentration vector y are set as shown in equations (6) and (7) below.

[0063] In this case, the likelihood for dataset D is expressed by the following equation (8), where σ２ σ is the error variance of the measurement of the dope concentration of wafer W. ２ This can be determined empirically. In one embodiment, the measurement error variance σ ２ This can be determined using a machine learning method based on multiple measurement results accumulated in the past. In one embodiment, the measurement error variance σ ２ This can be determined by performing multiple measurements on a wafer W after the film deposition process.

[0064] From Bayes' theorem, we obtain the following equation (9) for the posterior distribution from equations (5) and (8) above.

[0065] Rearranging equation (9) above, we can see that the posterior distribution follows a multivariate normal distribution (μ, Σ). In this case, the mean μ of the posterior distribution is the Bayesian estimate of the coefficient vector a. However, the covariance Σ and mean μ of the posterior distribution are expressed by the following equations (10) and (11).

[0066] The above explanation is merely one example of a case where the posterior distribution can be solved exactly, and the technology of this disclosure is not limited to this. For example, if the linear regression coefficients do not follow a normal distribution, they can be solved approximately. In this case, estimates can be obtained using approximation methods such as the Markov chain Monte Carlo method (MCMC method) or variational approximation.

[0067] Next, the Bayesian estimate determined above is used to determine if the verification data is abnormal (step St104 in Figure 9). In one embodiment, the abnormality determination in step St104 is performed on the verification data obtained by measurement after the verification run of interest in the verification processing set. In this embodiment, the verification run of interest may be a verification run during QC (hereinafter referred to as the "QC run").

[0068] In one embodiment, in step St104, the dope concentration at each measurement point in the verification data acquired in the QC run is compared with the dope concentration at each measurement point in the multiple regression equation (1) above using Bayesian estimates (hereinafter referred to as the "Bayesian model"). This comparison can be performed by taking the difference between the dope concentration at each measurement point in the verification data acquired in the QC run and the dope concentration at each measurement point in the Bayesian model, and determining whether the difference is below a predetermined threshold. If the difference is below the threshold at all measurement points ("YES" in Figure 9), the measurement results of the verification data acquired in the QC run can be determined to be normal. On the other hand, if there are measurement points where the difference exceeds the threshold ("NO" in Figure 9), the measurement results at least at the measurement points where the difference exceeds the threshold in the verification data acquired in the QC run can be determined to be abnormal.

[0069] For example, in Figure 10, the Bayesian model is shown as a solid line graph, and the dope concentration at each measurement point of the Bayesian model is shown as a square plot. Validation data obtained from measurements after the QC run is shown as a circle plot and a dashed line graph. In this case, the difference in dope concentration between measurement points P1 and P2 among measurement points P1 to P6 is represented by d1 and d2, indicated by the double-ended arrows in Figure 10. If d1 and d2 exceed the threshold, the measurement results at measurement points P1 and P2 can be judged as incorrect and abnormal.

[0070] The threshold can be determined based on the required accuracy for the target flow rate. In one embodiment, a Monte Carlo simulation is performed on a combination of an arbitrary measurement result and the dope concentration of a wafer W processed using the target flow rate based on the measurement result. By evaluating the contribution of the measurement result to the dope concentration, the threshold can be determined to fall within the range of the required accuracy.

[0071] In step St104, if the measurement results of the verification data obtained in the QC run are determined to be normal, the target flow rate for the wafer W to be processed in subsequent steps is determined using this verification data. That is, the target flow rate is corrected (step St105 in Figure 9). After step St105, the process may be repeated by returning to step St102 and executing a verification run using the corrected target flow rate.

[0072] In step St104, if the measurement results at one or more measurement points in the verification data obtained during the QC run are determined to be abnormal, abnormality processing is performed (step St110 in Figure 9).

[0073] In one embodiment, the abnormality handling in step St110 includes issuing a warning that there is an abnormality in the measurement result. After the warning is issued, the flow rate determination method is terminated, and for example, the operator of the film deposition apparatus 1 may inspect or replace the measuring device.

[0074] In one embodiment, the abnormality handling in step St110 includes replacing the measured values. For example, if the measurement results at measurement points P1 and P2 are abnormal, as shown in Figure 10, the measured values ​​at measurement points P1 and P2 are replaced with the dope concentration values ​​at measurement points P1 and P2 in the Bayesian model. Figure 11 shows a graph (circle plot and dashed line graph) of the verification data after the QC run when the measured values ​​at measurement points P1 and P2 are replaced. After replacing the measured values, the target flow rate is corrected using the replaced measured values ​​(step St105 in Figure 9).

[0075] Furthermore, when substituting measurement results, it is possible to substitute not only the measurement results at measurement points where the measurement results were determined to be abnormal, but also the measurement results at all measurement points with the dope concentration in the Bayesian model. In other words, if there is an abnormality, the measurement results may be discarded, and the Bayesian model may be used as the measurement result for that QC run.

[0076] According to the flow rate determination method including the above information processing method, abnormalities in the measurement results of the dope concentration can be detected in the verification run of interest, which is executed at any time in the verification processing set. Furthermore, if the measurement result is determined to be abnormal, an appropriate target flow rate can be determined by replacing at least a part of the measurement result with a Bayesian model. As a result, the distribution of dope concentration in the plane of the wafer W can be made to the desired state.

[0077] The embodiments disclosed herein should be considered in all respects as illustrative and not restrictive. The embodiments described above may be omitted, replaced, or modified in various ways without departing from the scope and spirit of the appended claims. For example, the constituent elements of the embodiments described above can be combined in any way. Such any combination will naturally yield the functions and effects of each constituent element in the combination, as well as other functions and effects that will be apparent to those skilled in the art from the description herein.

[0078] Furthermore, the effects described herein are merely descriptive or illustrative and not limiting. In other words, the technology relating to this disclosure may produce other effects that will be apparent to those skilled in the art from the description herein, in addition to or in lieu of the effects described herein.

[0079] 1. Film deposition apparatus 16. Injector 16h １　 1st supply port 16h ２　 Second supply port 100 Control unit L １　　 First gas line L ２　　 Second gas line W wafer

Claims

1. An information processing method comprising: using a plurality of pre-data, which are measurement results of the dope concentrations of a plurality of substrates processed in a pre-processing set, which is a set of a plurality of past film deposition processes in a film deposition apparatus; and a plurality of verification data, which are measurement results of the dope concentrations of a plurality of substrates processed in a verification processing set, which is a set of a plurality of film deposition processes of interest in the film deposition apparatus, to determine an estimated distribution of the dope concentrations for the verification processing set; obtaining the difference between the estimated distribution and the measurement results of the dope concentrations of substrates processed in a verification run, which is a film deposition process of interest in the verification processing set; and determining that the measurement results of the verification run of interest are abnormal if the difference exceeds a predetermined threshold.

2. The information processing method according to claim 1, wherein the prior data and the verification data are datasets including the coordinates of a plurality of measurement points on the substrate and the dope concentration at said measurement points, and the estimated distribution of the dope concentration is calculated as a posterior distribution in Bayes' theorem by assuming that the linear regression coefficients of the prior data follow a multivariate normal distribution when the coordinates of the measurement points are used as explanatory variables and the dope concentration is used as the dependent variable.

3. The information processing method according to claim 2, comprising comparing the measurement results of the verification run of interest with a Bayesian model using the mean of the linear regression coefficients of the posterior distribution for each of the multiple measurement points, thereby obtaining the difference of the measurement results.

4. The information processing method according to claim 3, comprising: determining an abnormality in the measurement result for each measurement point by obtaining the difference for each measurement point; and, for each measurement point where the measurement result is determined to be abnormal, replacing at least the value of the dope concentration at that measurement point with the value of the dope concentration at that measurement point in the Bayesian model.

5. The information processing method according to claim 4, comprising determining a target flow rate of gas to be supplied to substrates processed in the film deposition apparatus after the verification processing set, using the replaced measurement results.

6. The information processing method according to any one of claims 1 to 5, wherein, in the film deposition apparatus, when the verification processing set is performed using a certain susceptor, the pre-processing set is a set of multiple film deposition processes performed using another susceptor that was used immediately before the susceptor used in the film deposition apparatus in the verification processing set.

7. 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 based on a target flow rate; and a control unit, wherein the control unit performs control including: a plurality of pre-data which are measurement results of the dope concentrations of a plurality of substrates processed in a pre-processing set which is a set of a plurality of past film deposition processes in a film deposition apparatus; and a plurality of verification data which are measurement results of the dope concentrations of a plurality of substrates processed in a verification processing set which is a set of a plurality of film deposition processes of interest in the film deposition apparatus, to determine an estimated distribution of the dope concentrations for the verification processing set; to obtain the difference between the estimated distribution and the measurement result of the dope concentrations of a substrate processed in a verification run which is a film deposition process of interest in the verification processing set; and if the difference exceeds a predetermined threshold, to determine that the measurement result of the verification run of interest is abnormal.

8. The substrate processing apparatus according to claim 7, comprising a susceptor on which the substrate is placed, and a susceptor case in which the susceptor is housed and the processing space is formed inside.

9. A substrate processing apparatus according to claim 7, comprising a first gas line and a second gas line for supplying the gas to the injector, wherein the supply port of the injector has a first supply port formed in a portion other than the 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 from the first supply port to the processing space, and the gas supplied from the second gas line to the injector is configured to be supplied from the second supply port to the processing space.

10. The substrate processing apparatus according to claim 9, further comprising a flow rate controller configured to individually control the flow rates of the gases supplied from the first gas line and the second gas line, respectively.

Images