Semiconductor device manufacturing method

Abstract

To provide a method for manufacturing a semiconductor device capable of reducing the number of times of trials.SOLUTION: A method for manufacturing a semiconductor device includes the steps of: mounting a first susceptor on a deposition device; measuring a size of warpage of the first susceptor; setting a first initial deposition condition as a deposition condition of the deposition device according to the measured size of warpage of the first susceptor; and placing a plurality of first wafers on the first susceptor and forming a first film on the plurality of first wafers under the deposition condition. The step of setting the first initial deposition condition also includes a step of reading the first initial deposition condition from a storage medium in which a database is stored. The database includes a plurality of pieces of data associating the size of warpage of the susceptor with the initial deposition condition when the first film is formed.SELECTED DRAWING: Figure 12

Description

[Technical field]

[0001] The present disclosure relates to a method for manufacturing a semiconductor device. [Background technology]

[0002] Semiconductor films such as nitride semiconductor films are formed, for example, by placing a plurality of wafers on a susceptor installed in a film formation chamber (Patent Documents 1 and 2).

[0003] Susceptors may be warped. In addition, susceptors are frequently replaced because they are exposed to corrosive gases at high temperatures during film formation and wear out. If the direction or amount of warping of the susceptor differs before and after replacement, and the film formation conditions in the film formation chamber are the same before and after replacement, the direction or amount of warping of the susceptor changes, and the film thickness distribution of the film formed on the wafer also changes. For this reason, conventionally, after replacing the susceptor, a film is prototyped in order to determine mass-production film formation conditions suitable for mass production. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2004-95780 A [Patent Document 2] JP 2012-156196 A Summary of the Invention [Problem to be solved by the invention]

[0005] In the conventional manufacturing method, when the size of the susceptor is increased to increase the number of wafers that can be placed on one susceptor, the change in the direction or amount of warping of the susceptor after replacement increases, which increases the number of prototypes required to determine the film-forming conditions suitable for mass production.

[0006] An object of the present disclosure is to provide a method for manufacturing a semiconductor device that can reduce the number of prototypes. [Means for solving the problem]

[0007] The method for manufacturing a semiconductor device disclosed herein includes the steps of attaching a first susceptor to a film formation apparatus, measuring the magnitude of warpage of the first susceptor, setting first initial film formation conditions as film formation conditions of the film formation apparatus according to the measured magnitude of warpage of the first susceptor, and placing a plurality of first wafers on the first susceptor and forming a first film on the plurality of first wafers under the film formation conditions, wherein the step of setting the first initial film formation conditions includes the step of reading the first initial film formation conditions from a recording medium storing a database, and the database includes a plurality of data correlating the magnitude of warpage of the susceptor with initial film formation conditions when forming the first film. Effect of the Invention

[0008] According to the present disclosure, the number of prototypes can be reduced. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram showing an example of the inside of a film formation chamber used in the MOCVD method. [Diagram 2] FIG. 2 is an enlarged schematic view of a region R in FIG. [Diagram 3] FIG. 3 is a diagram showing the distribution of the growth rate of the GaN film formed on the wafer in region R in FIG. [Figure 4] FIG. 4 is a schematic diagram showing another example of the inside of a film formation chamber used in the MOCVD method. [Diagram 5] FIG. 5 is an enlarged schematic view of a region R in FIG. [Figure 6] FIG. 6 is a diagram showing the distribution of the growth rate of the GaN film formed on the wafer in region R in FIG. [Figure 7] FIG. 7 is a schematic diagram showing yet another example of the inside of a film formation chamber used in the MOCVD method. [Figure 8] FIG. 8 is an enlarged schematic view of a region R in FIG. [Figure 9] FIG. 9 is a diagram showing the distribution of the growth rate of the GaN film formed on the wafer in region R in FIG. [Figure 10] FIG. 10 is a diagram showing an example of the relationship between the magnitude of warpage of a susceptor and the difference in growth rate. [Figure 11] FIG. 11 is a flowchart showing a method for manufacturing a semiconductor device according to a reference example. [Figure 12] FIG. 12 is a flowchart showing a method for manufacturing a semiconductor device according to the embodiment. [Figure 13] FIG. 13 is a schematic diagram showing a film forming apparatus used in the method for manufacturing a semiconductor device according to the embodiment. [Figure 14] FIG. 14 is a schematic diagram showing a susceptor. [Figure 15] FIG. 15 is a schematic diagram showing a heater unit. [Figure 16] FIG. 16 is a diagram showing a method for approximating the shape of the surface of a susceptor. [Figure 17] FIG. 17 is a diagram showing an example of a straight line along which points along which film thicknesses are measured are arranged. [Figure 18] FIG. 18 is a flowchart showing a method for constructing a database. [Figure 19] FIG. 19 is a flowchart showing a method for manufacturing a semiconductor device according to a modified example of the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] [Description of the embodiments of the present disclosure] First, the embodiments of the present disclosure will be listed and described.

[0011] [1] A method for manufacturing a semiconductor device according to one embodiment of the present disclosure includes the steps of: attaching a first susceptor to a film formation apparatus; measuring a magnitude of warpage of the first susceptor; setting first initial film formation conditions as film formation conditions for the film formation apparatus according to the measured magnitude of warpage of the first susceptor; and placing a plurality of first wafers on the first susceptor and forming a first film on the plurality of first wafers under the film formation conditions, wherein the step of setting the first initial film formation conditions includes the step of reading the first initial film formation conditions from a recording medium storing a database, and the database includes a plurality of data correlating the magnitude of warpage of the susceptor with initial film formation conditions for forming the first film.

[0012] The database contains multiple pieces of data that associate the magnitude of the warp of the susceptor with the initial deposition conditions for forming the first film. Therefore, after the susceptor is attached, the initial deposition conditions that correspond to the magnitude of the warp of the susceptor are read from the database, and prototyping is started from these initial deposition conditions, making it possible to determine the mass production deposition conditions with a small number of prototyping runs.

[0013] [2] In [1], the film forming apparatus may have a plurality of heaters for heating the first susceptor, and the film forming conditions may include set temperatures of the plurality of heaters. In this case, a heater balance suitable for mass production can be easily determined by a small number of prototypes.

[0014] [3] In the method of [2], the heaters may be arranged concentrically. In this case, it is easy to control the temperature of the first wafers concentrically placed on the susceptor.

[0015] [4] In any of [1] to [3], the step of forming the first film may include a step of epitaxially growing a semiconductor film by metalorganic chemical vapor deposition, which makes it easier to determine mass production film formation conditions for a semiconductor film such as a nitride semiconductor film.

[0016] [5] In any of [1] to [4], the method may further include, after the step of forming the first film, a step of acquiring a first distribution of the thickness of the first film on the first wafer, and a step of determining the initial film formation conditions as mass production film formation conditions when the first distribution satisfies a predetermined film thickness distribution condition. In this case, mass production can be started promptly.

[0017] [6] In the method of [5], the method may further include a step of changing the film formation conditions according to the first distribution until the first distribution satisfies the film thickness distribution condition when the first distribution does not satisfy the film thickness distribution condition, a step of exchanging the first wafers, a step of forming the first film on the exchanged first wafers under the changed film formation conditions, and a step of acquiring the first distribution of the thickness of the first film, and a step of determining the immediately preceding film formation conditions as mass production film formation conditions when the first distribution satisfies the film thickness distribution condition. In this case, the mass production film formation conditions can be determined by a small number of trials.

[0018] [7] In the method of [5] or [6], after the step of determining the mass-production film-forming conditions, a step of placing a plurality of second wafers on the first susceptor and forming the first film on the plurality of second wafers under the mass-production film-forming conditions may be included. In this case, productivity can be improved by mass-producing the first film.

[0019] [8] In any of [5] to [7], after the step of determining the film formation conditions as mass-production film formation conditions, a step of additionally recording data correlating the magnitude of warpage of the first susceptor with the mass-production film formation conditions in the recording medium storing the database may be included. In this case, the enrichment of data makes it easier to reduce the number of prototypes required when replacing the susceptor thereafter.

[0020] [9] In any one of [1] to [8], the database may be stored in a recording medium connected to an outside of the deposition apparatus via a communication line, and the plurality of data may be added to the database from an outside of the deposition apparatus via the communication line. In this case, the database can be constructed without using the deposition apparatus.

[0021]

[10] In the method of [9], the first susceptor may have a serial number, and the plurality of data may be added to the database according to the serial number. In this case, for example, a vendor of the susceptor may add the plurality of data to the database.

[0022] [Details of the embodiment of the present disclosure] Hereinafter, the embodiments of the present disclosure will be described in detail, but the present disclosure is not limited thereto. In this specification and drawings, components having substantially the same functional configurations may be denoted by the same reference numerals to avoid redundant description.

[0023] First, the relationship between the shape of a susceptor and the thickness distribution of a semiconductor film when the semiconductor film is formed by metal organic chemical vapor deposition (MOCVD) will be described.

[0024] FIG. 1 is a schematic diagram showing an example of the inside of a film-forming chamber used in the MOCVD method. FIG. 1 shows a susceptor 11 that has a circular planar shape and can radially mount five wafers W. The susceptor 11 is not warped, and the upper surface of the susceptor 11 is flat. A wall 21 for restricting the lateral movement of the wafer W is provided on the upper surface of the susceptor 11 so as to surround each wafer W. A shower head 22 is installed above the susceptor 11, and a source gas 23 is sprayed from the shower head 22 toward the wafer W, forming a semiconductor film 26 on the surface of the wafer W facing the shower head 22. During film formation, the susceptor 11 rotates with its center as an orbital axis 31. The source gas 23 is sprayed from the shower head 22 directly above toward the wafer W, and a flow 25 of the source gas 23 flows from the center of the susceptor 11 toward the outer periphery. The source gas 23 not consumed in film formation becomes exhaust gas 24 and is discharged to the outside of the susceptor 11. In this embodiment, a GaN film is formed as the semiconductor film. In FIG. 1, the region R surrounded by the two-dot chain line is the region located on the outermost side among the five regions in which the wafer W is placed in the radial direction. When the susceptor 11 is used repeatedly, a GaN deposit 28 is also formed on the wall 21.

[0025] FIG. 2 is a schematic diagram showing an enlarged view of region R in FIG. 1. FIG. 3 is a diagram showing the distribution of the growth rate of the GaN film formed on the wafer W in region R in FIG. 1. FIG. 3 shows the results of a simulation. The horizontal axis of FIG. 3 indicates the radial position of the susceptor 11, and the vertical axis indicates the growth rate of the GaN film. The vertical axis indicates a reference growth rate GR0 for comparison with FIG. 6 and FIG. 9 described later. In this simulation, it is assumed that the temperature T of the susceptor 11 is uniform within the susceptor surface.

[0026] As shown repeatedly in FIG. 2, in the region R, the source gas 23 is sprayed from the shower head 22 directly above the wafer W, and there is a flow 25 of the source gas 23 from the center of the susceptor 11 to the periphery. In addition, when the susceptor 11 is used repeatedly, GaN deposits 28 are also formed on the wall 21. For this reason, Ga sublimes from the deposits 28 on the wall 21 located on the center side of the susceptor 11, and the Ga sublimation gas 27 flows into the region R. Therefore, as shown in FIG. 3, even if a warped susceptor 11 is used and the temperature of the susceptor 11 is uniform within the susceptor surface, the growth rate is not uniform. Specifically, in the region R of the susceptor 11, the growth rate is large near the center and decreases toward the periphery. Since the thickness of the GaN film depends on the growth rate, the thickness distribution of the GaN film is also similar.

[0027] Next, the growth rate and film thickness distribution when a susceptor with a convex warp is used will be described. Fig. 4 is a schematic diagram showing another example of the inside of a film formation chamber used in the MOCVD method. Fig. 4 shows a susceptor 12 that has a circular planar shape and can mount five wafers W in the radial direction. The susceptor 12 has a convex warp. Except for the warp, the susceptor 12 has the same configuration as the susceptor 11.

[0028] Fig. 5 is a schematic diagram showing an enlarged view of region R in Fig. 4. Fig. 6 is a diagram showing the distribution of the growth rate of the GaN film formed on the wafer W in region R in Fig. 4. Fig. 6 shows the results of a simulation. The horizontal axis of Fig. 6 indicates the radial position of the susceptor 12, and the vertical axis indicates the growth rate of the GaN film. In this simulation, it is assumed that the temperature T of the susceptor 12 is uniform within the susceptor surface.

[0029] As shown in Fig. 5, when a susceptor 12 having a convex warp is used, the distance between the wafer W and the shower head 22 in the region R is larger than when a susceptor 11 having no warp is used. Therefore, a higher proportion of the source gas 23 becomes exhaust gas 24 before reaching the wafer W due to the flow 25. Therefore, as shown in Fig. 6, the overall growth rate is lower than in the example of Fig. 3, and the decrease in the growth rate on the outer periphery side in the region R is remarkable.

[0030] Next, the growth rate and film thickness distribution when a susceptor with concave warpage is used will be described. Fig. 7 is a schematic diagram showing yet another example of the inside of a film formation chamber used in the MOCVD method. Fig. 7 shows a susceptor 13 that has a circular planar shape and can mount five wafers W in the radial direction. The susceptor 13 has a concave warpage. Except for the warpage, the susceptor 13 has the same configuration as the susceptor 11.

[0031] Fig. 8 is a schematic diagram showing an enlarged view of region R in Fig. 7. Fig. 9 is a diagram showing the distribution of the growth rate of the GaN film formed on the wafer W in region R in Fig. 7. Fig. 9 shows the results of a simulation. The horizontal axis of Fig. 9 indicates the radial position of the susceptor 13, and the vertical axis indicates the growth rate of the GaN film. In this simulation, it is assumed that the temperature T of the susceptor 13 is uniform within the susceptor surface.

[0032] As shown in Fig. 8, when a susceptor 13 having a concave warpage is used, the distance between the wafer W and the shower head 22 in the region R is smaller than when a susceptor 11 having no warpage is used. Therefore, even if there is a flow 25, the proportion of the source gas 23 that becomes exhaust gas 24 before reaching the wafer W is low. Therefore, as shown in Fig. 9, compared to the example in Fig. 3, the growth rate is high overall, and the decrease in the growth rate on the outer periphery side in the region R is subtle.

[0033] FIG. 10 is a diagram showing an example of the relationship between the magnitude of warpage of the susceptor and the difference in growth rate. The horizontal axis of FIG. 10 shows the magnitude of warpage of the susceptor. The magnitude of warpage indicates the height of the outer periphery based on the center of the susceptor, and a positive magnitude of warpage indicates that the susceptor is warped concavely, and a negative magnitude of warpage indicates that the susceptor is warped convexly. The vertical axis of FIG. 10 shows an outline of the tendency of the difference in growth rate in the wafer W between the region located closest to the center of the susceptor in the wafer W and the region located farthest from the center of the susceptor. As shown in FIG. 10, the difference in growth rate in the wafer W is affected by the magnitude of warpage of the susceptor. In the example shown in FIG. 10, when the susceptor is along a concave shape, the difference in growth rate is smaller than when it is along a convex shape.

[0034] 1 to 10, even if the deposition conditions such as temperature within the susceptor are uniform and common, the growth rate and thickness distribution of a film such as a GaN film differ depending on the warpage of the susceptor. Therefore, after replacing the susceptor, it is desirable to specify the mass-production deposition conditions so that the uniformity of the film thickness within the wafer within the replaced susceptor becomes a value suitable for mass production.

[0035] (Reference example) Next, a method for manufacturing a semiconductor device according to a reference example will be described. Here, a process from replacing a susceptor to identifying mass-production film-forming conditions suitable for mass production and forming a film under the mass-production film-forming conditions will be described. Fig. 11 is a flowchart showing the method for manufacturing a semiconductor device according to a reference example.

[0036] In the method for manufacturing a semiconductor device according to the reference example, first, a new susceptor is attached to the film formation chamber (step S101). Next, the film formation conditions for the first film formation performed after the replacement of the susceptor are stored in a storage medium 142 such as a memory (step S104). The film formation conditions include the temperature setting conditions of the heater that heats the susceptor. The initial film formation conditions immediately after the replacement are always the same conditions. Next, multiple wafers are placed on the susceptor, the film formation conditions are read from the storage medium 142, and a semiconductor film such as a GaN film is formed on the multiple wafers under the read film formation conditions. Then, the multiple wafers on which the film has been formed are removed from the film formation chamber (step S105). Next, the film thickness of the semiconductor film is measured from multiple points to obtain film thickness distribution data (step S106). Next, it is determined whether the film thickness distribution satisfies a predetermined film thickness distribution condition (step S107).

[0037] If the film thickness distribution does not satisfy the film thickness distribution condition, the film formation conditions are changed according to the film thickness distribution, and the information on the film formation conditions stored in the storage medium 142 is updated (step S108). Then, in step S105, a plurality of wafers are placed on a susceptor, the updated film formation conditions are read from the storage medium 142, a semiconductor film such as a GaN film is formed on the plurality of wafers under the read film formation conditions, and the plurality of wafers on which the semiconductor film is formed are taken out of the film formation apparatus (step S105). Thereafter, the processes from step S105 to step S108 are repeated until the film thickness distribution satisfies the film thickness distribution condition.

[0038] When the film thickness distribution satisfies the film thickness distribution condition, the film formation conditions in the immediately preceding film formation are determined as mass production film formation conditions (step S109). Then, multiple wafers are placed on a susceptor, the film formation conditions are read from the storage medium 142, film formation is performed under the read film formation conditions, and the multiple wafers on which film formation has been performed are removed from the film formation chamber (step S110). As a mass production process, film formation on multiple wafers is repeated a predetermined number of times (step S111).

[0039] For convenience of the flowchart, step S105 is depicted as a separate process from step S110, but they are performed in the same deposition chamber using the same susceptor, etc.

[0040] By using such a method, the mass production film formation conditions can be determined, and the film can be formed under the mass production film formation conditions.

[0041] However, since the initial film formation conditions after the susceptor is replaced in step S104 are always fixed regardless of the degree of warpage of the susceptor, the frequency of repetition of the processes from step S105 to step S109 increases when the susceptor is enlarged. This lengthens the time from replacement of the susceptor to the start of mass production, suppressing improvement in productivity. In addition, if the number of prototypes increases until film formation conditions suitable for mass production are set, the number of wafers and source gases used increases, leading to an increase in the material cost of the final mass-produced product.

[0042] The manufacturing method of a semiconductor device according to the embodiment described below is aimed at reducing the frequency of repetition of the processes from step S105 to step S109. Fig. 12 is a flowchart showing the manufacturing method of a semiconductor device according to the embodiment. Fig. 13 is a schematic diagram showing a film forming apparatus used in the manufacturing method of a semiconductor device according to the embodiment.

[0043] The film forming apparatus 1 used in the method for manufacturing a semiconductor device according to the embodiment shown in FIG. 13 is, for example, an MOCVD apparatus, and includes a film forming chamber 2, a heater unit 3, a shower head 4, and a control unit 5. In the method for manufacturing a semiconductor device according to the embodiment, a semiconductor film is epitaxially grown by MOCVD. The heater unit 3 and the shower head 4 are disposed in the film forming chamber 2. A susceptor 7 having a wall 9 is attached on the heater unit 3, and the heater unit 3 heats the susceptor 7. The shower head 4 ejects raw material gas toward a plurality of wafers W placed on the susceptor 7. The control unit 5 controls the heater unit 3 and the shower head 4. The control unit 5 includes a recording medium 41 such as a hard disk drive that stores a database 6, and a storage medium 42 such as a memory that stores data such as film forming conditions.

[0044] FIG. 13 shows an embodiment in which the film forming apparatus 1 has a control unit 5, but the film forming apparatus 1 does not necessarily have to have the control unit 5. The control unit 5 may be provided externally and connected to the film forming apparatus 1 via a communication line or the like. The database 6 may also be configured to allow data to be written from the outside via a communication line or the like. In this case, the database is stored in an external recording medium connected to the outside of the film forming apparatus 1 via a communication line. An external vendor providing the susceptor 7 may write or add data on the warpage of the susceptor 7 from the outside to the database 6 under a serial number that can identify each susceptor 7 written on each individual susceptor 7.

[0045] Here, the heater unit 3 will be described. FIG. 14 is a schematic diagram showing the susceptor 7. FIG. 14 is a diagram showing the structure of the upper surface side of the susceptor 7 facing the shower head 4. FIG. 15 is a schematic diagram showing the heater unit 3. FIG. 15 is a diagram showing the structure of the upper surface side of the heater unit 3 facing the lower surface side of the susceptor 7. As shown in FIG. 14, the susceptor 7 has, for example, 10 pocket regions 8 on one circumference on which the wafers W are placed, and further has 16 pocket regions 8 on the other circumference outside the above. That is, the susceptor 7 is configured so that 26 wafers W can be placed. Although omitted in FIG. 14, a wall similar to the wall 21 is provided around the pocket region 8. As shown in FIG. 15, the heater unit 3 has a plurality of heaters 30 arranged concentrically. The heaters 30 are arranged so as to overlap with the pocket regions 8. The temperatures of the plurality of heaters 30 can be controlled independently. Therefore, by adjusting the set temperatures of the plurality of heaters 30, the balance of the heat radiation temperatures (heater balance) which differ depending on the concentric positions of the heater unit 3 can be adjusted.

[0046] The database 6 includes a plurality of data items that correspond to the magnitude of warpage of the susceptor and the initial film forming conditions when forming a semiconductor film. The initial film forming conditions include, for example, the initial set temperatures of the plurality of heaters 30. That is, the database 6 stores data items of conditions related to the initial heater balance of the heater unit 3 in association with the magnitude of warpage of the susceptor. For example, the database 6 stores data items of the initial heater balance when the magnitude of warpage of the susceptor is −1 mm, data items of the initial heater balance when the magnitude of warpage of the susceptor is +0.5 mm, and data items of the initial heater balance when the magnitude of warpage of the susceptor is +1.0 mm. It is preferable that the database 6 includes a larger number of data items.

[0047] 12, in the method for manufacturing a semiconductor device according to the embodiment, first, a new susceptor 7 is attached to the film formation chamber 2 (step S101). Specifically, the susceptor 7 is attached on the heater unit 3. The susceptor 7 is an example of a first susceptor.

[0048] Next, the magnitude of warpage of the susceptor 7 is measured and obtained (step S102). The magnitude of warpage of the susceptor 7 is the height difference between the highest and lowest positions on the surface of the susceptor 7. Here, as an example, when the susceptor 7 is warped concavely, that is, when the center side is lower than the outer periphery side, the height difference is considered to be positive, and when the susceptor 7 is warped convexly, that is, when the center side is higher than the outer periphery side, the height difference is considered to be negative. The position of the surface of the susceptor 7 can be measured, for example, using a contact or non-contact displacement meter. When measuring the shape of the susceptor 7, it is not necessary to measure the position of the entire surface of the susceptor 7. For example, the positions may be measured at three or more points between the center and the outer periphery, and the shape of the susceptor 7 may be approximated to a circular arc from the results. FIG. 16 is a diagram showing a method of approximating the shape of the surface of the susceptor 7. In the example shown in FIG. 16, the diameter of the susceptor 7 is 500 mm, and the positions of a total of six points are measured on a line passing through the center: two points 50 mm away from the center, two points 150 mm away, and two points 220 mm away, and the shape of the surface of the susceptor 7 is approximated to a circular arc 7X.

[0049] A mechanism for measuring the degree of warpage of the susceptor 7 may be provided outside the film forming apparatus 1. The degree of warpage of the susceptor 7 may be obtained before attachment to the film forming chamber 2. Alternatively, the degree of warpage of the susceptor 7 may be provided in advance by a manufacturer (external vendor) of the susceptor 7 together with related information according to individual identification information such as the serial number of the susceptor 7. Such related information may be stored in advance in the database 6 from outside via a communication line or the like.

[0050] Note that the curvature may be used instead of the magnitude of the warpage. In the case of using the curvature, the magnitude of the warpage can be uniquely determined from the curvature and diameter of the susceptor, and therefore, this is equivalent to using the magnitude of the warpage.

[0051] Next, the initial film formation conditions are obtained and set (step S103). Specifically, the initial film formation conditions corresponding to the magnitude of warpage of the susceptor 7 are read from the recording medium 41 storing the database 6. If the database 6 does not contain data matching the magnitude of warpage of the susceptor 7, for example, the initial film formation conditions for the magnitude of warpage with the smallest difference may be read. That is, in this embodiment, the initial film formation conditions depend on the magnitude of warpage of the susceptor 7. The initial film formation conditions include, for example, conditions related to the set temperature of each heater 30, that is, conditions related to the heater balance of the heater unit 3. The initial film formation conditions are an example of first initial film formation conditions.

[0052] Next, the initial film formation conditions acquired in step S103 are stored in the storage medium 42 as film formation conditions (step S104). Next, a plurality of wafers W are placed on the susceptor 7, the film formation conditions are read from the storage medium 42, a semiconductor film is formed on the plurality of wafers W under the read film formation conditions, and the plurality of wafers W on which the semiconductor film is formed are taken out of the film formation apparatus 1 (step S105). The semiconductor film formed in step S105 may be a single film or a laminated film in which a plurality of films are laminated. For example, a SiC wafer may be used as the wafer W, and a laminated film in which an AlN film, a GaN film, an AlGaN film, and a GaN film are laminated in this order from the wafer W side may be formed as the semiconductor film. In addition, the wafer W is placed so that, for example, a notch or an orientation flat formed on the wafer W is located on a straight line connecting the center of the susceptor 7 and the center of the wafer W. The wafer W is an example of a first wafer, and the semiconductor film is an example of a first film.

[0053] Next, the thickness of the semiconductor film is measured to obtain the film thickness distribution (step S106). The thickness of the semiconductor film can be measured, for example, using a spectroscopic ellipsometer. The thickness of the semiconductor film is measured, for example, at multiple points on a straight line that connected the center of the susceptor 7 and the center of the wafer W during film formation. The thickness of the semiconductor film is measured at 2 mm intervals, for example, when the diameter of the wafer W is about 100 mm (4 inches). FIG. 17 is a diagram showing an example of a straight line on which points at which the film thickness is measured are arranged. For example, as shown in FIG. 17, an orientation flat 10 is formed on the wafer W, and the film thickness is measured at multiple points on a straight line L that perpendicularly passes through the center O of the wafer W and the orientation flat 10.

[0054] Next, it is determined whether the film thickness distribution in the wafer W satisfies a predetermined film thickness distribution condition (step S107). For example, it is determined whether the film thickness is within a predetermined range.

[0055] If the film thickness distribution does not satisfy the film thickness distribution condition, the film formation conditions are changed according to the film thickness distribution, and the information on the film formation conditions stored in the storage medium 42 is updated (step S108). Then, in step S105, the multiple wafers W are replaced, the updated film formation conditions are read from the storage medium 42, and a semiconductor film is formed on the multiple wafers W under the read film formation conditions. Thereafter, the processes from step S105 to step S108 are repeated until the film thickness distribution satisfies the film thickness distribution condition.

[0056] When the film thickness distribution satisfies the film thickness distribution condition, the film formation conditions in the immediately preceding film formation are set as the mass production film formation conditions and are determined as the final film formation conditions (step S109). Then, multiple wafers W are placed on a susceptor, the film formation conditions are read from the storage medium 42, film formation is performed under the read film formation conditions, and the multiple wafers on which film formation has been performed are removed from the film formation chamber (step S110). As a mass production process, film formation on multiple wafers is repeated a predetermined number of times (step S111). The wafer W used in step S110 is an example of a second wafer.

[0057] By using such a method, the mass production film formation conditions can be determined, and film formation can be performed under the mass production film formation conditions. After the semiconductor film is formed in the mass production process, a protective film, wiring, etc. are formed to complete the semiconductor device.

[0058] In this embodiment, the initial film formation conditions depend on the magnitude of warpage of the susceptor 7. Therefore, the frequency of repeating the processes from step S105 to step S108 until the film thickness distribution satisfies the film thickness distribution conditions can be reduced. In other words, the number of prototypes can be reduced. In some cases, it may be possible to determine the mass production film formation conditions without repeating the processes from step S105 to step S108.

[0059] Therefore, the time from replacement of the susceptor 7 to the start of mass production can be shortened, and the productivity can be improved. Also, the amounts of wafers W and source gas used for trial production can be reduced, and the material costs can be reduced.

[0060] In this embodiment, the heater temperature setting is adjusted as an example of a film formation condition. Since the film thickness distribution is particularly susceptible to the effect of temperature, this embodiment makes it easy to determine a heater balance suitable for appropriate mass production. In addition, since the multiple heaters 30 are arranged concentrically, it is easy to control the temperature of the multiple wafers W placed concentrically on the susceptor 7.

[0061] When forming a semiconductor film such as GaN or AlGaN by MOCVD, the susceptor is easily consumed. However, according to this embodiment, even if the susceptor is replaced, mass production film formation conditions can be determined with a small number of prototypes.

[0062] Here, we will explain the method of constructing the database 6. Figure 18 is a flow chart showing the method of constructing the database 6.

[0063] In this construction method, first, the susceptor 7 is attached to the film formation chamber (step S101). Next, the magnitude of warpage of the susceptor 7 is measured (step S102). Next, initial film formation conditions are obtained (step S103). The initial film formation conditions may be film formation conditions that do not depend on the warpage of the susceptor 7, as in the reference example.

[0064] Next, the initial film formation conditions acquired in step S103 are stored in the storage medium 42 as film formation conditions (step S104). Next, a plurality of wafers W are placed on the susceptor 7, the film formation conditions are read from the storage medium 42, a semiconductor film is formed on the plurality of wafers W under the read film formation conditions, and the plurality of wafers W on which the semiconductor film is formed are taken out of the film formation apparatus 1 (step S105). Next, the film thickness of the semiconductor film is measured, and the film thickness distribution is obtained (step S106). Next, it is determined whether the film thickness distribution satisfies a predetermined film thickness distribution condition (step S107).

[0065] If the film thickness distribution does not satisfy the film thickness distribution condition, the film formation conditions are changed according to the film thickness distribution, and the information on the film formation conditions stored in the storage medium 42 is updated (step S108). Then, in step S105, the multiple wafers W are replaced, the updated film formation conditions are read from the storage medium 42, and a semiconductor film is formed on the multiple wafers W under the read film formation conditions. Thereafter, the processes from step S105 to step S108 are repeated until the film thickness distribution satisfies the film thickness distribution condition.

[0066] When the film thickness distribution satisfies the film thickness distribution condition, the film formation conditions in the film formation performed immediately before are determined to be the initial film formation conditions corresponding to the magnitude of warpage obtained in step S102 (step S209), and this initial film formation condition is recorded in database 6 (step S210).

[0067] In this manner, one piece of data correlating the magnitude of warpage of the susceptor 7 with the initial film formation conditions for forming a semiconductor film is added to the database 6. By executing such processing for a predetermined number of susceptors 7, the database 6 is constructed (step S211).

[0068] 12, even after the mass-production film-forming conditions are determined (step S109), data correlating the magnitude of warpage of the wafer W with the mass-production film-forming conditions is preferably additionally recorded in the recording medium 41 storing the database 6 as data correlating the magnitude of warpage of the susceptor 7 with the initial film-forming conditions (step S212). This is because the abundance of data can further reduce the frequency of the processes from step S105 to step S108 when the susceptor 7 is subsequently replaced.

[0069] The set temperature of the heaters 30 may be adjusted independently for all of the heaters 30, or the heaters 30 may be divided into a plurality of groups and the set temperature may be adjusted commonly within each group. For example, if the heater unit 3 includes ten heaters 30, the heaters 30 may be divided into two groups of five heaters each, and the set temperature of the five heaters 30 in each group may be set to a common temperature.

[0070] Although the embodiments have been described in detail above, the present invention is not limited to the specific embodiments, and various modifications and changes are possible within the scope of the claims. [Explanation of symbols]

[0071] 1: Film deposition equipment 2: Deposition chamber 3: Heater unit 4, 22: Shower head 5: Control unit 6: Database 7, 11, 12, 13: Susceptor 7X: Arc 8: Pocket area 9, 21: Wall 10: Orientation Flat 21: Wall 23: Raw material gas 24: Exhaust gas 25: Flow 26: Semiconductor film 27: Ga sublimation gas 28: Adhesion 30: Heater 31: Revolution axis 41: Recording medium 42, 142: Storage medium L: Straight line O: Center R:Region T: Temperature W: Wafer

Claims

1. attaching a first susceptor to a film forming apparatus; measuring the magnitude of warpage of the first susceptor; setting a first initial film formation condition as a film formation condition of the film formation apparatus according to the measured magnitude of warpage of the first susceptor; placing a plurality of first wafers on the first susceptor and forming a first film on the plurality of first wafers under the film forming conditions; having The step of setting the first initial film-forming condition includes a step of reading the first initial film-forming condition from a recording medium storing a database, The database includes a plurality of data items correlating the magnitude of warpage of the susceptor with initial film-forming conditions for forming the first film. A method for manufacturing a semiconductor device.

2. the film forming apparatus has a plurality of heaters for heating the first susceptor, The method for manufacturing a semiconductor device according to claim 1 , wherein the film formation conditions include set temperatures of the plurality of heaters.

3. The method for manufacturing a semiconductor device according to claim 2 , wherein the plurality of heaters are arranged concentrically.

4. 4. The method for manufacturing a semiconductor device according to claim 1, wherein the step of forming the first film includes a step of epitaxially growing a semiconductor film by metalorganic chemical vapor deposition.

5. After the step of forming the first film, obtaining a first distribution of thickness of the first film over the first wafer; determining the initial film-forming conditions as mass-production film-forming conditions when the first distribution satisfies a predetermined film-thickness distribution condition; The method for manufacturing a semiconductor device according to claim 1 , further comprising the steps of:

6. When the first distribution does not satisfy the film thickness distribution condition, until the first distribution satisfies the film thickness distribution condition. changing the film formation conditions in response to the first distribution; exchanging the plurality of first wafers; forming the first film on the replaced first wafers under the changed film formation conditions; obtaining the first distribution of thicknesses of the first film; Repeating the steps of: determining, when the first distribution satisfies the film thickness distribution condition, the immediately preceding film formation condition as a mass production film formation condition; The method for manufacturing a semiconductor device according to claim 5 , further comprising the steps of:

7. After the step of determining the mass production film formation conditions, placing a plurality of second wafers on the first susceptor and forming the first film on the plurality of second wafers under the mass production film formation conditions; The method for manufacturing a semiconductor device according to claim 5 or 6, comprising:

8. 8. The method for manufacturing a semiconductor device according to claim 5, further comprising the step of: after the step of determining the film formation conditions as mass production film formation conditions, additionally recording data correlating the magnitude of warpage of the first susceptor with the mass production film formation conditions on the recording medium storing the database.

9. the database is stored in an external recording medium connected to the outside of the film forming apparatus via a communication line; 9. The method of claim 1, wherein the plurality of data are added to the database from outside the film forming apparatus via the communication line.

10. 10. The method for manufacturing a semiconductor device according to claim 9, wherein the first susceptor has a serial number, and the plurality of data are added to the database in accordance with the serial number.

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