JP2022161543A - Design method for gas holes and design device for gas holes - Google Patents

Abstract

To provide a method for designing gas holes which efficiently designs an arrangement of gas holes.SOLUTION: A method for designing gas holes which supply a gas into a processing container of a semiconductor manufacturing apparatus includes a step of creating a model for evaluating film quality, on the basis of, an arrangement of the gas holes, and a plurality of data sets for comparing film formation results obtained by supplying the gas from the gas holes in the arrangement of the gas holes and actually forming films, and a step of calculating an evaluation value of film quality in the arrangement of the gas holes using the model, and optimizing the arrangement of the gas holes.SELECTED DRAWING: Figure 5

Description

The present disclosure relates to a gas hole design method and a gas hole design apparatus.

As one of the methods for forming a thin film such as a silicon oxide film on a substrate such as a wafer in a semiconductor manufacturing apparatus, CVD ( Chemical Vapor Deposition) method, ALD (Atomic Layer Deposition) method, and the like are known. Such a semiconductor manufacturing apparatus may have a shower head for gas supply (see Patent Document 1, for example). Patent Document 1 discloses a semiconductor manufacturing apparatus having source gas supply means and auxiliary gas supply means.

JP 2018-78233 A

The present disclosure provides a gas hole design method that efficiently designs the placement of the gas holes.

In view of the above problems, there is provided a method of designing a gas hole for supplying gas into a processing container of a semiconductor manufacturing apparatus. a step of generating a model for film quality evaluation based on a plurality of data sets associated with film formation results; calculating and optimizing the placement of the gas holes.
, have

It is possible to provide a gas hole design method for efficiently designing the arrangement of gas holes.

FIG. 1 is a cross-sectional view showing a configuration example of a semiconductor manufacturing apparatus according to one embodiment; A plan view of the semiconductor manufacturing apparatus of FIG. Cross-sectional view along the concentric circles of the rotary table of the semiconductor manufacturing apparatus of FIG. Hardware configuration diagram of an example of a shower head design device An example flowchart illustrating the overall flow of a showerhead design method Top view of an example of a shower head A functional block diagram illustrating an example of functions of a shower head design device divided into blocks. Explanatory diagram of an example explaining the kernel and the shape of the kernel An illustration of an example of film thickness locations evaluated on a wafer Schematic diagram of an example explaining film thickness estimation using kernels Schematic diagram of an example of black-box optimization An example of a flowchart diagram showing the procedure for the kernel shape determination unit to optimize the shape of the kernel using the black-box optimization method. Diagram showing the effect of internal parameters on the kernel's objective function A diagram showing the shape of the kernel obtained after adjustment in correspondence with the position on the Y line of the shower head. Illustration of an example explaining the accuracy of the model Explanatory diagram of an example for explaining determination of hole layout by tree structure search Flowchart diagram of an example showing the procedure for the gas hole optimization part to optimize the hole layout Schematic diagram of an example to explain the hole layout optimization method Diagram showing an optimized example hole layout A diagram showing the film formation results calculated by the design equipment using the optimized hole layout. A diagram showing actual film formation results (example) when film formation is performed using a shower head with an optimized hole layout for semiconductor manufacturing equipment.

Non-limiting exemplary embodiments of the present disclosure will now be described with reference to the accompanying drawings. In all the attached drawings, the same or corresponding members or parts are denoted by the same or corresponding reference numerals, and overlapping descriptions are omitted.

[Configuration example of a semiconductor manufacturing apparatus having a shower head]
First, an example of a semiconductor manufacturing apparatus equipped with a shower head will be described with reference to FIGS. 1 to 3. FIG. The semiconductor manufacturing apparatus 1 of FIG. 1 is an example of a processing apparatus that executes the control method of the rotary table of the present disclosure.

A semiconductor manufacturing apparatus 1 of the present disclosure includes a chamber 1 having a substantially circular planar shape, and a rotary table 2 provided in the chamber 1 and having a rotation center at the center of the chamber 1 . The chamber 1 has a container body 12 having a cylindrical shape with a bottom, and a top plate 11 airtightly and detachably arranged on the upper surface of the container body 12 via a seal member 13 such as an O-ring. is doing.

The rotary table 2 is fixed to a cylindrical core portion 21 at its central portion, and the core portion 21 is fixed to the upper end of a rotating shaft 22 extending in the vertical direction so as to be rotatable. The rotating shaft 22 passes through the bottom portion 14 of the chamber 1, and its lower end is attached to a driving portion 23 that rotates the rotating shaft 22 around a vertical axis. The rotating shaft 22 and the drive unit 23 are housed in a cylindrical case body 20 with an open top. A bellows 16 is provided between the bottom portion 14 of the container body 12 and the case body 20 . Thereby, the case body 20 is airtightly attached to the lower surface of the bottom portion 14 of the chamber 1, and the internal atmosphere of the case body 20 is isolated from the external atmosphere. The drive unit 23 may be a motor.

Further, outside the bellows 16 , an elevating mechanism 17 is provided to move the rotary table 2 up and down and change the height of the rotary table 2 . The lifting mechanism 17 lifts the rotary table 2 so that the distance between the ceiling surface 45 and the wafer W can be changed in accordance with the lifting of the rotary table 2 . The lifting mechanism 17 may be realized by various configurations as long as the rotary table 2 can be moved up and down.

A first exhaust port 610 is provided at the outer edge of the chamber 1 and communicates with an exhaust pipe 630 . The exhaust pipe 630 is connected to the vacuum pump 640 via the pressure regulator 650 so that the inside of the chamber 1 can be exhausted from the first exhaust port 610 .

FIG. 2 is a diagram for explaining the structure inside the chamber 1, and shows the structure inside the chamber 1 when the semiconductor manufacturing apparatus 1 according to the embodiment is viewed from above, with the top plate 11 omitted. ing. On the surface of the rotary table 2, as shown in FIG. 2, a plurality of (five in the illustrated example) semiconductor wafers (hereinafter referred to as "substrates" or "wafers") W are placed along the direction of rotation (circumferential direction). A circular recess 24 is provided for this purpose. It should be noted that the wafer W is shown in one recess 24 in FIG. The recess 24 has an inner diameter (for example, 2 mm) slightly larger than the diameter of the wafer W (for example, 300 mm) and a depth approximately equal to the thickness of the wafer W. Department. Therefore, when the wafer W is placed on the concave portion 24, the surface of the wafer W and the surface of the rotary table 2 (area where the wafer W is not placed) are at the same height. The bottom surface of the concave portion 24 is formed with through holes (none of which are shown) through which e.g., three elevating pins for supporting the back surface of the wafer W and elevating the wafer W pass therethrough. The transfer port 15 transfers the wafer W between the external transfer arm 10 and the rotary table 2 .

A reaction gas nozzle 31, a reaction gas nozzle 32, and separation gas nozzles 41 and 42 each made of quartz, for example, are arranged above the rotary table 2. As shown in FIG. In the illustrated example, separation gas nozzles 41, reaction gas nozzles 31, separation gas nozzles 42, and reaction gas nozzles are arranged clockwise from the transfer port 15 (rotating direction of the turntable 2 indicated by an arrow 9) at intervals in the circumferential direction of the chamber 1. 32 are arranged in order. These nozzles 41 , 31 , 42 , 32 have their respective gas introduction ports 41 a , 31 a , 42 a , 32 a fixed to the outer peripheral wall of the container body 12 . Thus, the container body 12 is installed so as to be introduced into the chamber 1 from the outer peripheral wall of the chamber 1 and extend parallel to the rotary table 2 along the radial direction of the container body 12 .

A first reaction gas supply source in which a first reaction gas is stored is connected to the reaction gas nozzle 31 via an on-off valve and a flow rate regulator (both not shown). A second reaction gas supply source that stores a second reaction gas that reacts with the first reaction gas is connected to the reaction gas nozzle 32 via an on-off valve and a flow rate regulator (both not shown).

Here, the first reaction gas is preferably a gas containing a semiconductor element or a metal element, and a gas that can be used as an oxide film or a nitride film when it becomes an oxide or nitride is selected. The second reactive gas is selected from an oxidizing gas or a nitriding gas that can react with a semiconductor element or metal element to produce a semiconductor oxide or semiconductor nitride, or a metal oxide or metal nitride. Specifically, the first reaction gas is preferably an organic semiconductor gas or organometallic gas containing a semiconductor element or metal element. In addition, it is preferable that the first reaction gas is a gas having an adsorptive property with respect to the surface of the wafer W. As shown in FIG. The second reactive gas is an oxidizing gas or a nitriding gas that is capable of undergoing an oxidation reaction or a nitridation reaction with the first reaction gas adsorbed on the surface of the wafer W and depositing a reaction compound on the surface of the wafer W. is preferred.

Specifically, for example, the first reaction gas is a reaction gas containing silicon, and an organic aminosilane such as diisopropylaminosilane or bistertialbutylaminosilane (BTBAS) that forms SiO2 as an oxide film or SiN as a nitride film. is. Alternatively, the first reactive gas is tetrakisdimethylaminohafnium (hereinafter referred to as “TDMAH”) which is a hafnium-containing reactive gas and forms HfO as an oxide film. Alternatively, the first reaction gas is a reaction gas containing titanium, such as TiCl4 that forms TiN as a nitride film. Also, the second reaction gas is an oxidizing gas such as ozone gas (O3) or oxygen gas (O2). Alternatively, the second reaction gas is a nitriding gas such as ammonia gas (NH3).

In addition, the separation gas nozzles 41 and 42 are connected to supply sources of rare gases such as Ar and He and inert gases such as nitrogen (N2) gas via opening/closing valves and flow rate regulators (both not shown). . The inert gas supplied from the separation gas nozzles 41 and 42 is also called separation gas. In the embodiment, N2 gas, for example, is used as the inert gas.

In addition to the first reaction gas supply source, the reaction gas nozzle 31 includes a second reaction gas supply source, an inert gas such as a rare gas such as Ar and He, and a separation gas such as nitrogen (N2) gas. source is connected. A switch (not shown) is operated to switch which gas to supply. In addition to the second reaction gas supply source, the reaction gas nozzle 32 is connected to a first reaction gas supply source and an inert gas supply source that is also used as a separation gas. It is provided so as to be able to switch which gas is supplied.

A region defined below the reactive gas nozzle 31 serves as a first processing region P1 for causing the wafer W to absorb the first reactive gas. A region defined below the reaction gas nozzle 32 serves as a second processing region P2 in which the first reaction gas absorbed by the wafer W in the first processing region P1 is oxidized or nitrided.

Two convex portions 4 are attached to the back surface of the top plate 11 in the chamber 1 so as to protrude toward the rotary table 2 . The convex portion 4 constitutes a separation area D together with separation gas nozzles 41 and 42 . That is, the region below the separation gas nozzles 41 and 42 separates the first processing region P1 and the second processing region P2 and prevents the mixing of the first reaction gas and the second reaction gas. becomes. The convex portion 4 has a substantially fan-shaped planar shape in which the top portion is cut in an arc shape. , the outer arc of which is arranged along the inner peripheral surface of the container body 12 of the chamber 1 . As shown in FIG. 1, the projecting portion 5 is provided so as to surround the outer periphery of the core portion 21 to which the rotary table 2 is fixed.

The convex portion 4 shown in FIG. 2 is attached to the back surface of the top plate 11 . For this reason, the lower surface of the convex portion 4 is lower than the ceiling surfaces 45 located on both sides of the lower surface in the circumferential direction.

A groove (not shown) is formed in each of the convex portions 4 at the center in the circumferential direction, and separate gas nozzles 41 and 42 are accommodated therein. Gas ejection holes are formed in the separation gas nozzles 41 and 42 .

The reaction gas nozzles 31 and 32 are provided in the vicinity of the wafer W apart from the ceiling surface 45 . The N2 gas supplied from the separation gas nozzle 42 is a counterflow to the first reaction gas from the first processing region P1 and the second reaction gas (oxidizing gas or nitriding gas) from the second processing region P2. work as Therefore, the first reaction gas from the first processing region P1 and the second reaction gas from the second processing region P2 are separated by the convex portion 4 and the N2 gas. Therefore, it is suppressed that the first reaction gas and the second reaction gas are mixed and reacted in the chamber 1 .

A first exhaust port 610 and a second exhaust port 620 are formed between the rotary table 2 and the inner peripheral surface of the container body 12 . An auto pressure controller (APC) 650 is provided in the exhaust pipe 630 between the first exhaust port 610 and the vacuum pump 640 shown in FIG. The second exhaust port 620 is likewise connected to a vacuum pump (not shown respectively) via an exhaust pipe provided with a pressure regulator. The exhaust pressures of the first exhaust port 610 and the second exhaust port 620 are configured to be independently controllable.

As shown in FIG. 1, the space between the rotary table 2 and the bottom 14 of the chamber 1 is provided with a heater unit 7 as heating means. A heater unit 7 provided below the turntable 2 heats the wafer W on the turntable 2 via the turntable 2 to a temperature (eg, 450° C.) determined by the process recipe.

The case body 20 is provided with a purge gas supply pipe 72 for supplying N2 gas as a purge gas for purging. Further, in the bottom portion 14 of the chamber 1, a plurality of purge gas supply pipes 73 for purging the installation space of the heater unit 7 are provided at predetermined angular intervals in the circumferential direction below the heater unit 7. As shown in FIG. A ring-shaped cover member 71 is provided on the lower side near the periphery of the rotary table 2 , and a lid member 7 a covering the heater unit 7 is provided between the heater unit 7 and the rotary table 2 . The lid member 7a can be made of quartz, for example. This prevents gas from entering the area where the heater unit 7 is provided.

By supplying N2 gas from the purge gas supply pipe 72 and the purge gas supply pipe 73, the flow of these N2 gases causes the space 481 shown in FIG. and mixing of the gas in the space 482 can be suppressed.

A separation gas supply pipe 47 is connected to the central portion of the top plate 11 of the chamber 1, and configured to supply N2 gas as a separation gas to the space 481 between the top plate 11 and the core portion 21. It is The separation gas supplied to the space 481 is discharged toward the periphery along the surface of the turntable 2 on the wafer mounting area side through the narrow space 46 between the protrusion 5 and the turntable 2 . Space 46 may be maintained at a higher pressure than spaces 481 and 482 by the separation gas. Thus, the space 46 allows the first reactant gas supplied to the first processing region P1 and the second reactant gas supplied to the second processing region P2 to mix through the space 48. Suppressed.

The semiconductor manufacturing apparatus 1 is provided with a control section 90 that controls the operation of the semiconductor manufacturing apparatus 1 . Various sensors are installed in the semiconductor manufacturing apparatus 1 . A temperature sensor 60 for measuring the temperature of the rotary table 2 is installed as an example of various sensors. The temperature sensor 60 is provided, for example, above the rotary table 2, and uses the difference in material between the rotary table 2 and the wafer W to determine whether the wafer W placed on the placement part is detached or not. A radiation thermometer for measuring the temperature of the table 2 may be used. A temperature sensor 60 is arranged in contact or non-contact with the turntable 2 to measure the temperature of the turntable 2 .

When the temperature sensor 60 is a radiation thermometer, for example, the radiation thermometer is provided on the window outside the chamber 1 to measure the intensity of infrared rays or visible light emitted from the object to measure the temperature of the object. By using a radiation thermometer as the temperature sensor 60, the temperature of the rotary table 2 can be measured at high speed and without contact. Temperature sensor 60 transmits the measured temperature to control unit 90 . The controller 90 acquires the temperature measured by the temperature sensor 60 and uses it to control the elevation of the rotary table 2 .

FIG. 3 is a cross-sectional view along a concentric circle of the turntable 2 of the semiconductor manufacturing apparatus 1 of FIG.

The top plate 11 in the separation area D is provided with a generally fan-shaped convex portion 4 . The convex portion 4 is attached to the back surface of the top plate 11 . In the space below the top plate 11, there are a flat and low ceiling surface (hereinafter referred to as “first ceiling surface 44”) which is the lower surface of the convex portion 4, and on both sides of the first ceiling surface 44 in the circumferential direction. A ceiling surface higher than the first ceiling surface 44 (hereinafter referred to as "second ceiling surface 45") is formed.

As shown in FIG. 3, the convex portion 4 forming the first ceiling surface 44 has a fan-shaped planar shape with an arc-shaped top portion. A groove portion 43 is formed in the convex portion 4 so as to extend in the radial direction at the center in the circumferential direction. Separation gas nozzles 41 and 42 are accommodated in groove 43 . In order to prevent mixing of the processing gases, the peripheral edge of the convex portion 4 is bent in an L shape so as to face the outer end surface of the rotary table 2 and be slightly separated from the container body 12. is doing.

Above the reaction gas nozzle 31, a nozzle is provided so that the first processing gas flows along the wafer W and the separation gas avoids the vicinity of the wafer W and flows toward the top plate 11 side. A cover 230 is provided. The nozzle cover 230 includes a cover body 231 and a straightening plate 232, as shown in FIG. The cover body 231 has a general box shape with an open bottom side for accommodating the reaction gas nozzle 31 . The rectifying plate 232 is a plate-like body connected to the upstream side and the downstream side in the rotation direction of the rotary table 2 at the open end on the lower surface side of the cover body 231 . A side wall surface of the cover body 231 on the rotation center side of the turntable 2 extends toward the turntable 2 so as to face the tip of the reaction gas nozzle 31 . Moreover, the side wall surface of the cover body 231 on the outer edge side of the rotary table 2 is notched so as not to interfere with the reaction gas nozzles 31 . Note that the nozzle cover 230 is not essential and may be provided as needed.

[Configuration example of shower head design device]
FIG. 4 is a diagram showing an example of the hardware configuration of the shower head designing device 50. As shown in FIG. The showerhead design device 50 has a typical computer configuration. The shower head design device 50 has a CPU (Central Processing Unit) 501 , a ROM (Read Only Memory) 502 and a RAM (Random Access Memory) 503 .

The showerhead design device 50 also has an auxiliary storage device 504 , an operation device 505 , a display device 506 , an I/F (Interface) device 507 and a drive device 508 . Each piece of hardware of the shower head designing apparatus 50 is interconnected via a bus 509 .

The CPU 501 executes various programs installed in the auxiliary storage device 504 .

A ROM 502 is a non-volatile memory and functions as a main memory. The ROM 502 stores various programs, data, etc. necessary for the CPU 501 to execute various programs installed in the auxiliary storage device 504 .

A RAM 503 is a volatile memory such as a DRAM (Dynamic Random Access Memory) or an SRAM (Static Random Access Memory), and functions as a main storage device. The RAM 503 provides a work area that is expanded when various programs installed in the auxiliary storage device 504 are executed by the CPU 501 .

Auxiliary storage device 504 is a nonvolatile mass storage device that stores various programs. The auxiliary storage device 504 may be a non-volatile large-capacity storage medium such as an HDD (Hard Disk Drive) or an SSD (Solid State Drive). Various programs include a program for optimizing the arrangement of the gas holes of the showerhead 36 (hereinafter simply referred to as hole layout).

The operation device 505 is an input device used when the administrator inputs various instructions to the shower head design device 50 . The display device 506 is a display device that displays internal information of the showerhead designing device 50 and information acquired from the outside.

The I/F device 507 is a connection device for connecting to a communication line and communicating with the group supervisory controller 40 .

A drive device 508 is a device for setting a recording medium. Recording media include media that record information optically, electrically, or magnetically, such as CD-ROMs, flexible disks, and magneto-optical disks. Also, the recording medium may include a semiconductor memory or the like that electrically records information, such as a ROM or a flash memory.

Various programs to be installed in the auxiliary storage device 504 are installed by, for example, setting a distributed recording medium in the drive device 508 and reading the various programs recorded in the recording medium by the drive device 508. . Alternatively, various programs installed in the auxiliary storage device 504 may be installed by being downloaded from a predetermined server.

The showerhead design device 50 may also have a GPU (Graphics Processing Unit). GPUs, which are processors used to perform graphics processing, can perform large amounts of computation in parallel, and can perform computations required for machine learning at high speed.

[Overall work flow]
By the way, the shower head has hundreds to thousands of gas ejection holes, and the hole layout of the shower head 36 affects the concentration distribution of the gas on the wafer and the flow velocity distribution of the gas. It may affect the film quality (film quality).

Adjustments to the hole layout of the showerhead 36 were often made based on the experience of experienced process engineers. However, the number of holes in the shower head is many, ranging from several hundred to several thousand. was difficult even for experienced engineers. Moreover, in order to adjust the hole layout, it is necessary to prepare a plurality of shower heads in advance or open a jig to block the holes, and in both cases, many man-hours are required. Therefore, in layout adjustment, it is required not only to aim for good film quality but also to reduce the number of adjustments.

Therefore, with reference to FIG. 5, the overall flow of the method for designing the showerhead 36 of the present disclosure, which reduces the number of adjustments (man-hours) and allows adjustment of the optimum hole layout, will be described. FIG. 5 is an example of a flowchart illustrating the overall flow of the design method for the shower head 36. As shown in FIG.

A developer manufactures a shower head for adjustment (S101). An adjustable showerhead is a showerhead with test gas holes (hereinafter simply referred to as holes) to realize various hole layouts (see FIG. 6).

Next, the developer mounts a plurality of adjusting showerheads with different hole layouts on the semiconductor manufacturing apparatus 1, and actually forms a film (S102). This film formation result is used for a data set to be described later. In the present disclosure, film formation is actually performed with, for example, seven hole layouts, but the number of hole layout types may be one. However, it is considered that the more types of hole layouts that are actually deposited, the easier it is to obtain hole layouts with good deposition quality (film quality). The film quality is an attribute of film formation used in film formation evaluation, such as uniformity of film thickness distribution, film reflectance, or film density.

Then, in the present disclosure, the design device 50 determines the hole layout in two steps. Step 1 is a step of generating a model for outputting an evaluation value (a film thickness distribution may be output) of film formation in an arbitrary hole layout using the film formation result. The evaluation value is a numerical representation of the uniformity of the film thickness distribution. Step 2 is a step of outputting an evaluation value while using this model in an optimization method such as a tree structure search, and optimizing the hole layout.

Therefore, first, as step 1, the design device 50 generates a model using the film formation results (S103).

Next, as step 2, the design device 50 outputs evaluation values while using the model, and optimizes the hole layout (S104).

The developer reproduces the optimized hole layout with an adjustment showerhead or an actual showerhead, and performs film formation with the semiconductor manufacturing apparatus 1 (S105).

The developer compares the predicted (expected) film thickness distribution and the actual film thickness distribution, and determines whether the difference between the predictions is within the allowable range. It is determined whether the difference from the distribution is within a preset allowable range (S106).

If the difference between the expected film thickness distribution and the actual film thickness distribution is not within the allowable range, the model is generated again. A shower head for adjusting multiple hole layouts based on the optimized hole layout is mounted on the semiconductor manufacturing apparatus 1, and film formation is actually performed (S107). Thereafter, the process is executed again from step S103. The showerhead for adjustment of a plurality of hole layouts based on the optimized hole layout refers to one in which the open/close state of one or more holes is changed based on the hole layout optimized in S105. .

If the difference between the expected film thickness distribution and the actual film thickness distribution is within the allowable range, the developer decides to adopt the optimized hole layout for the actual machine (S108).

Below, mainly steps 1 and 2 (steps S103 and S104) explained in FIG. 5 will be explained in detail.

[Example of shower head]
FIG. 6 shows a plan view of the showerhead 36. As shown in FIG. 6 shows a hole 61 of the shower head 36 viewed from a plane parallel to the wafer W. FIG. A large number of holes 61 are arranged in the shower head 36 . Although the number of holes 61 is small in FIG. 6A for convenience of drawing, several hundred to several thousand holes are actually arranged. The entire length of the wafer W is covered by the shower head 36 as a whole. Therefore, when the diameter of the wafer W is 300 mm, the longitudinal length of the shower head 36 is also approximately 300 mm. The length in the lateral direction may be determined as appropriate.

In FIG. 6A, the size and shape of the hole 61 of the shower head 36 are one, but as shown in FIG. 6B, the size and shape of the hole 61 may have variations. In FIG. 6B, the fourth row from the top is a round hole, and the size of the hole 61 is designed such that the first row<second row=third row<fourth row. Also, the hole in the fifth row is a square hole 62 . Square holes 62 may exist in any row, and round holes 61 and square holes 62 may be mixed in one row. Also, the size of the square hole 62 may be different for each row. Also, the shape of the hole 62 may be a triangle, a rhombus, or the like. Therefore, the present disclosure also allows the shape of the hole 61 to be optimized.

In the design method of the present disclosure, the developer selectively closes the holes 61 and 62 of the showerhead 36 for adjustment using a tape, a jig, an opening/closing mechanism, or the like, thereby realizing a plurality of hole layouts. A hole layout is an arrangement of holes.

[About functions]
FIG. 7 is an example of a functional block diagram for explaining the functions of the design device 50 of the shower head 36 by dividing them into blocks. The showerhead 36 design device 50 is an example of a gas hole design device. A design device 50 for the showerhead 36 has a kernel shape determining unit 51 , a model generating unit 52 , a film thickness estimating unit 53 , and a gas hole optimizing unit 54 . These functions of the design device 50 of the shower head 36 are functions or means implemented by the CPU 501 executing a program expanded from the auxiliary storage device 504 to the RAM 503 .

The kernel shape determining unit 51 and model generating unit 52 are mainly used in step 1 above, and the film thickness estimating unit 53 and gas hole optimizing unit 54 are mainly used in step 2 above.

Although the details will be described later, the kernel shape determining unit 51 determines the kernel (the influence of the holes in the showerhead 36 on the film thickness) by a technique such as black-box optimization. The model generator 52 generates a model that outputs an evaluation value when the film thickness is generated using this kernel. The evaluation value is, for example, a numerical value of the uniformity of the film thickness. The model has a function to output the film thickness distribution.

The film thickness estimator 53 outputs an evaluation value of the film thickness when the film is formed with an arbitrary hole layout using the generated model. The gas hole optimizing unit 54 optimizes the hole layout of the shower head 36 using an optimization method (search algorithm) such as a tree structure search based on the film thickness evaluation value output by the film thickness estimating unit 53. become Details will be described later.

[About kernel]
First, the kernel will be described with reference to FIG. FIG. 8 is a diagram for explaining the kernel 63 and the shape of the kernel 63. As shown in FIG. A kernel 63 is a one-dimensional representation of the effect of one (or more) holes in the showerhead 36 on film thickness. That is, it can also be said to be a film thickness model of one hole.

The X-axis in FIG. 8 corresponds to the longitudinal position of the showerhead 36, with X=0 corresponding to the center of the hole. The Y-axis of FIG. 8 corresponds to film thickness. The longitudinal direction of the shower head 36 is the radial direction of the rotary table 2, assuming that the shower head 36 is attached to the rotary table 2 (see FIG. 9A). The film thickness of the kernel 63 becomes larger (thicker) toward the center of the hole, and becomes smaller (thinner) away from the center of the hole.

However, it is difficult to estimate how each hole 61 of the shower head 36 affects the film thickness only by empirical rules. Therefore, in the present disclosure, the kernel shape determining unit 51 determines the shape of the kernel 63 for each hole 61 of the shower head 36 by a method called black box optimization.

The normal form of kernel 63 may be, for example, a normal distribution. In FIG. 8, three kernels 63 with different shapes are shown. κ (kappa), which will be described later in FIG. 8, is one of the internal parameters that determine the shape of the kernel 63, and correlates with the size in the Y-axis direction (film thickness). σ is one of the internal parameters that determine the shape of the kernel 63 and correlates with the spread in the X-axis direction. The intrinsic parameters also include the skewness λ (a statistic representing how much the shape is skewed from the normal distribution). The shape of the kernel 63 is not limited to the three shown, and may take any shape.

[Evaluated film thickness]
FIG. 9 is a diagram for explaining locations of film thicknesses to be evaluated on the wafer W. FIG. FIG. 9(a) is a simplified view of FIG. 2, and FIG. 9(b) shows an enlarged view of one wafer W placed on the rotary table 2. As shown in FIG. The film thickness at the location indicated by the arrow 65 is the film thickness actually measured for the film thickness formed by the actual machine. Also, in the phase in which the model outputs the evaluation value in step 2, it is the film thickness estimated for film formation evaluation. A location on the wafer W indicated by an arrow 65 is hereinafter referred to as a Y line. The Y line is substantially parallel to the longitudinal direction of the showerhead 36 when the wafer W passes under the showerhead 36 .

The wafer W is revolved on the rotary table 2. In the Y line, the side closer to the axis of rotation is called the IN side, and the side farther from the axis of rotation is called the OUT side. In addition, the position above the Y line is represented by setting the IN side end to 0 mm. When the diameter of the wafer W is 300 mm, the edge on the OUT side is 300 mm.

FIG. 10 is a diagram schematically showing film thickness estimation using the kernel 63. As shown in FIG. FIG. 10(a) is an arbitrary hole layout for which the film thickness is desired. In FIG. 10, the arrangement of the holes 61 is represented by squares, but this does not represent the shape of the holes 61, but simply shows the holes 61 aligned in the longitudinal direction and the lateral direction of the shower head 36. . The hatched holes 61 are open, and the other holes 61 are closed.

FIG. 10(b) is a diagram showing the shape of the same number of kernels 63 as the number of holes in the shower head 36 for each column. This kernel 63 is optimized by the kernel shape determination unit 51 .

Therefore, by summing up the kernels 63 for each column, the film thickness distribution in the Y-line direction can be estimated. FIG. 10(c) shows the Y-line film thickness distribution estimated by the film thickness estimator 53 by summing the kernels. As shown in FIG. 10(c), the film thickness is obtained at any position on the Y line.

By placing the physical assumption of the kernel 63 in this way, the model can output the film thickness with less data than the number of holes 61 that the shower head 36 has.

In the present disclosure, the function of summing the kernels 63 and outputting the Y-line film thickness distribution and film thickness evaluation values is referred to as a model. The model generator 52 generates this model. The model generation unit 52 uses the shape of the kernel 63 determined by the kernel shape determination unit 51 to generate a model for estimating the film thickness evaluation value when the film is formed using the shower head 36 having an arbitrary hole layout.

The model adds the film thickness model (the shape of the kernel 63 itself) generated by the kernel 63 determined for each hole for each row of holes of the showerhead 36 . That is, the model estimates the film thickness distribution with respect to the hole layout input, quantifies the evaluation of the estimated film thickness distribution, and outputs the evaluation value of the film thickness.

[Determination of kernel shape by black-box optimization (step 1)]
Based on the above, kernel optimization will be described in detail.

FIG. 11 is a schematic diagram of black-box optimization. Inputs for black-box optimization are, for example, the following two.
(1) Objective function of kernel 63 (an example of the first objective function)
(2) Conditions for internal parameters
(1) The objective function of kernel 63 is a function for evaluating the validity of kernel 63 . The kernel 63 objective function numerically outputs the validity of the kernel 63 . Validity is, for example, a numerical representation of the difference between the film thickness distribution obtained by the kernel and the film thickness of the data set.

Also, the objective function of the kernel 63 uses the "data set" and the "information on the framework of the model".
• A data set is a set of a "hole layout" and a corresponding "film thickness distribution". As illustrated in FIG. 5, the developer uses a tuning showerhead to perform the actual deposition, preferably with a multiple hole layout. The developer measures the film thickness of the Y line and creates a film thickness distribution. This is the dataset.

The data set may include information on process conditions that the semiconductor manufacturing apparatus 1 executes. The information about the process conditions may include at least one of the type of gas, the pressure inside the processing chamber, the temperature of the stage on which the wafer W is placed, the plasma output, the film formation time, and the rotational speed of the turntable.
・The information of the framework of the model is the information of how to calculate the "film thickness distribution" using the "hole layout" and the "kernel". The method for calculating the film thickness distribution has been described with reference to FIG.

(2) Internal parameter conditions are the domain and initial values of the internal parameters of the kernel 63 . The internal parameters are coefficients related to the size, spread, skewness, etc. described above. In the present disclosure, the following four (a, b, σ, λ) are internal parameters.

κ: Influence on film thickness around hole (κ= a * r + b). κ affects the thickness (size) of the film.

a: Effect (slope) of position on influence on film thickness.

b: Influence on film thickness regardless of position (intercept).

σ: Width of kernel 63;

λ: distortion of kernel 63;

Note that r is the distance from 0 mm of the Y line (not an internal parameter). That is, the internal parameter a of κ is defined such that the size of the kernel 63 changes with a constant gradient with respect to the Y line. This is to reproduce the effect on the film thickness that the speed at which the wafer W passes under the shower head 36 is faster toward the OUT side of the rotary table 2 .

The kernel shape determination unit 51 uses (1) and (2) as inputs for black box optimization, performs trial and error (learning), and determines the internal parameters of the kernel 63 . In other words, the output of black-box optimization is the optimized kernel 63 (the values of the internal parameters of the kernel 63). A kernel 63 value is output for every hole. Alternatively, the difference between rows may be ignored and the data may be output for each column in the Y line direction. The kernel shape determination unit 51 may also output the value (validity) of the objective function of the optimized kernel 63 .

FIG. 12 is an example of a flow chart showing a procedure for the kernel shape determination unit 51 to optimize the shape of the kernel 63 using the black box optimization technique. The kernel shape determination unit 51 optimizes the shape of the kernel 63 for each of one or more holes in the longitudinal direction of the showerhead 36 .

First, the kernel shape determining unit 51 calculates the film thickness by summing the effects of the kernels 63 on the film thickness in the hole layout of the data set based on the information of the framework of the model (S11). The kernel shape determination unit 51 performs the same processing on all data sets obtained.

Next, the kernel shape determination unit 51 puts the film thickness of the hole layout obtained in the data set and the calculated film thickness into the kernel 63 as the objective function and determines the validity of the kernel 63 (S12).

The kernel shape determining unit 51 determines whether the validity of all data sets is good, or whether the extent of improvement in validity when the internal parameters are changed is a certain value or less (S13). Alternatively, the process ends when steps S11 and S12 are repeated a certain number of times.

If the determination in step S13 is No, the kernel shape determination unit 51 gradually changes the parameters of the kernel 63 within the domain included in the internal parameter (2) condition (S14). A technique called Bayesian optimization is known as a method of changing parameters.

Bayesian optimization selects the next search point (internal parameters in this disclosure) by optimizing a surrogate function called an Acquisition function instead of an objective function that is computationally expensive to evaluate. A Gaussian process is often used to construct this acquisition function. Description of Bayesian optimization is omitted.

If the determination in step S3 is Yes, the kernel shape determining unit 51 uses the finally obtained values of the internal parameters as the optimized shape of the kernel 63 .

FIG. 13 is an example of the effect of internal parameters on the objective function of the kernel 63. FIG. FIG. 13 shows the effects of b and σ among the four internal parameters on the objective function of the kernel. The contour map of FIG. 13 represents the magnitude of the difference (sum of squares) between the film thickness distribution obtained by the kernel and the film thickness of the data set, and regions with the same color have approximately the same magnitude of difference. From FIG. 13, it can be said that b and σ corresponding to the lowest contour region 66 are the optimal intrinsic parameters. Although FIG. 13 is black and white for convenience of drawing, the degree of validity is indicated by color.

FIG. 14 is a diagram showing the shape of the kernel 63 obtained after adjustment in correspondence with the position of the showerhead 36 on the Y line. Although FIG. 14 shows the shape of kernels 63 of three holes 61 at positions of 0 mm, 150 mm, and 300 mm, the shapes of kernels 63 are actually obtained for the number of holes 61 .

As shown in FIG. 14, the internal parameters are adjusted so that the closer to the 300 mm side of the Y line (toward the OUT side of the rotary table 2), the smaller the degree of influence of the kernel 63 becomes. This means that the gas concentration becomes thinner toward the outer side of the rotary table 2, which is also physically valid. Also, depending on how the objective function of the kernel 63 is selected, some kernel values may become negative when the internal parameters of the kernel 63 are optimized. Such physical plausibility may be difficult to explain in order to successfully reproduce the film thickness of the dataset.

FIG. 15 is a diagram explaining the accuracy of the model. In FIG. 15, the horizontal axis indicates the position of the Y line, and the vertical axis indicates the film thickness. Each graph shown in FIG. 15 is as follows.
• Graph 1 is the actual deposition and measured film thickness used in the data set. FIG. 15 shows one of seven film formation results.
・Graph 2 shows measured values of film thickness actually formed under a certain hole layout.
• Graph 3 is the film thickness estimate output by the model when the same hole layout as Graph 2 is input to the model.

Comparing graphs 2 and 3, it can be seen that there is no significant difference between the estimated values and the measured values, and that the shape of the kernel generated by black-box optimization is effective.

[Determination of Hole Layout by Tree Structure Search (Step 2)]
As described above, a model for outputting the film thickness distribution is generated with the optimized kernel 63, so that the gas hole optimization unit 54 can determine the optimum hole layout.

FIG. 16 is a diagram for explaining determination of hole layouts by tree structure search. Inputs for the tree structure search are, for example, the following two.
(1) Hole layout objective function (an example of the second objective function)
(2) Hole layout conditions
(1) The hole layout objective function is a function for evaluating the film thickness distribution. The hole layout objective function uses the model. This model is the model generated by the model generation unit 52 in step 1 . The evaluation value may be, for example, the standard deviation of the film thickness at fixed intervals on the Y line.

(2) The hole layout conditions are the domain and initial values of the hole layout. The definition area is, for example, how many holes the showerhead 36 may be drilled. The initial value is the initial hole layout for tree structure search.

The gas hole optimizing unit 54 uses (1) and (2) as inputs for the tree structure search, performs trial and error, and determines the hole layout. Thus, the output of the tree search is the optimized hole layout. The gas hole optimization unit 54 may also output the value of the objective function of the optimized hole layout (for example, the evaluation value output by the model, etc.).

FIG. 17 is an example of a flowchart showing a procedure for the gas hole optimization unit 54 to optimize the hole layout. FIG. 18 is a diagram schematically showing the hole layout optimization method, and FIG. 18 describes the corresponding step numbers of FIG. 17 . The tree structure search method as shown in FIGS. 17 and 18 is called Monte Carlo tree search.

First, the gas hole optimizing unit 54 sets a reference pattern of the hole layout that serves as a starting point for optimization (S21). The reference pattern may be determined based on some knowledge, may be a pattern in which open holes are uniformly arranged, or may be a pattern in which the open/closed state is randomly determined. However, restrictions similar to the domain of (2) hole layout conditions are considered.

Next, the gas hole optimizing unit 54 assumes a pattern in which only one hole is opened and closed from the reference pattern, and the film thickness estimating unit 53 calculates an evaluation value using the model (S22). That is, using the model generated by the model generating unit 52, the film thickness estimating unit 53 estimates the film thickness and further calculates the evaluation value. As shown in FIG. 18, an evaluation value is obtained for each of patterns 110, 111, and 112 whose open/closed state differs from the current pattern (here, the reference pattern) by one open/closed state. The pattern 110 is, for example, a pattern obtained by opening a hole in the reference pattern (this hole was closed in the reference pattern), and the pattern 111 is, for example, a pattern in which another hole is closed in the reference pattern (this hole was opened in the reference pattern). ), and the pattern 112 is, for example, a pattern in which another hole is opened from the reference pattern (this hole was closed in the reference pattern).

Next, the gas hole optimization unit 54 selects N patterns for continuing the search based on the calculated evaluation value (S23). The gas hole optimization unit 54 selects N patterns in descending order of evaluation values, for example. In FIG. 18, hatched circles represent selected patterns.

The gas hole optimization unit 54 repeats steps S22 and S23 based on the pattern left in step S23. As a result, the depth of the pattern search is increased by one for each cycle. Also, N patterns are selected for each layer. The gas hole optimization unit 54 repeats steps S22 and S23 until the predetermined upper limit of depth is reached (S24). For example, although FIG. 18 shows up to depth 3, it is only for convenience of drawing, and the upper limit depth may change depending on the calculation speed of the design device 50, the allowable time, and the like. In FIG. 18, the pattern selected for each layer in step S23 is hatched.

When the predetermined upper limit of depth is reached (Yes in S24), the gas hole optimization unit 54 propagates the highest evaluation value for each layer from the deepest pattern to the reference pattern (S25). . Supplementary explanation is given with reference to FIG. First, the branch 67 on the left side of FIG. 18 will be described.

"Evaluation value propagated from depth 4 1.5 < Value of evaluation value propagated from depth 4 1.7"
→ Propagate 1.7 to depth 2 "Evaluation value propagated from depth 3 1.1 < Evaluation value propagated from depth 3 1.7"
→ Propagate 1.7 to depth 1 Next, the branch 68 on the right side of FIG. 18 will be described.

"Evaluation value propagated from depth 4 1.2 < Value of evaluation value propagated from depth 4 1.4"
→ Propagate 1.4 to depth 2 "Evaluation value propagated from depth 3 1.4 < Evaluation value propagated from depth 3 1.5"
→ Propagate 1.5 to depth 1 As described above, two evaluation values 1.7 and 1.5 at depth 1 are determined, so 1.7 is propagated to the reference pattern.

The gas hole optimization unit 54 selects one change leading to the pattern with the highest evaluation value, and updates the reference pattern (S26). In the example of FIG. 18, the pattern 110 propagating 1.7 is the next reference pattern.

The gas hole optimization unit 54 repeats steps S22 to S26, and when the reference pattern has been updated a certain number of times (S27), ends the search. Therefore, the gas hole optimizing unit 54 can repeatedly select the pattern with the highest evaluation value from the tree structure to determine the optimum hole layout.

FIG. 19 shows an example of an optimized hole layout. FIG. 19 shows part of the showerhead 36 . FIG. 19(a) is the hole layout before optimization, and FIG. 19(b) is the hole layout after optimization. The hole layout before optimization has a pattern in which the open state and the closed state are relatively biased, but a more complicated pattern is obtained in FIG. 19(b). Thus, according to the showerhead design method of the present disclosure, a hole layout with a pattern that is difficult for humans to adjust is obtained.

The optimum hole layout may vary depending on factors such as gas flow rate, susceptor temperature, plasma output (for example, applied voltage of a plasma source (not shown)), gas species, and film formation recipe. It is even better if the hole layout is optimized for each.

FIG. 20 is an example of a diagram showing film formation results calculated by the design device 50 using the optimized hole layout. The computer-calculated deposition result is the film thickness distribution output by the model based on the optimized hole layout. The horizontal axis of FIG. 20 is the position on the Y line, and the vertical axis is the film thickness. The contents of each graph are as follows.
• Graph 101 is an estimate of deposition results for the optimized hole layout.
• The dashed line graph 102 is the film thickness used in the data set.

Graph 101 (estimated value of film formation result) shows reduced film thickness variation in the Y line compared to the film formation result with the least variation among the seven film formation results (dotted lines) before optimization. It has been confirmed that the standard deviation is less than half. In this way, an optimum hole layout that improves film thickness distribution can be obtained on a computer.

FIG. 21 shows actual film formation results when film formation is performed with the shower head 36 having the optimized hole layout of the semiconductor manufacturing apparatus 1 . In FIG. 21, the hole layout is optimized only for about 30% of all the holes of the shower head 36 near 0 mm of the Y line.

The horizontal axis of FIG. 21 is the position on the Y line, and the vertical axis is the film thickness. The contents of each graph are as follows.
- Graph 103 is the actual film formation result by the hole layout before optimization.
• Graph 104 is the actual deposition result with the optimized hole layout.

Comparing the graphs 103 and 104, the variation in film thickness is improved when the position on the Y line is about 70 mm or less. Therefore, by optimizing the hole layout, we were able to improve the film thickness distribution in the actual machine.

[Main effects]
As described above, the method of designing the showerhead of the semiconductor manufacturing apparatus 1 of the present disclosure uses a statistical model using actual film formation data, so physical phenomena that cannot be reproduced by general simulations are also possible. It is possible to determine the hole layout with high accuracy.

In addition, by using a model designed based on physical phenomena such as gas diffusion and adsorption, the number of experimental samples required for kernel optimization can be reduced.

In addition, by using an optimization algorithm to determine the shape of the kernel and the hole layout, a lot of trial and error can be done on the computer, so it is easier to find a good hole layout compared to manual optimization. .

Also, by using the present disclosure in combination with conventional techniques for optimizing controllable factors such as gas flow rate, susceptor temperature, or plasma power (e.g., applied voltage of the plasma source), a broader search than ever before can be achieved. Optimization can be done in space. For example, these elements can be included in the search space and searched in kernel shape optimization. This is expected to make it easier to find combinations of element values and hole layouts that yield better deposition results.

[others]
Embodiments can be modified and improved in various ways without departing from the scope and spirit of the appended claims. The items described in the above multiple embodiments can take other configurations within a consistent range, and can be combined within a consistent range.

For example, in the present disclosure, the hole layout is optimized mainly for uniform film thickness. good.

In addition, in the present disclosure, the hole layout is optimized for the showerhead 36 to which the reaction gas nozzle 31 supplies gas.

In addition, in the present disclosure, the black box optimization method was described in step 1, and the tree structure search method was described in step S2. Optimization techniques may be utilized.

The semiconductor manufacturing apparatus 1 of the present disclosure includes atomic layer deposition (ALD) equipment, capacitively coupled plasma (CCP), inductively coupled plasma (ICP), radial line slot antenna (RLSA), electron cyclotron resonance plasma (ECR), helicon wave plasma (HWP) is applicable to any type of device. In addition, any semiconductor manufacturing apparatus that forms a film using a shower head can be applied.

REFERENCE SIGNS LIST 1 semiconductor manufacturing equipment 2 rotary table 36 shower head 51 kernel shape determining unit 52 model generating unit 53 film thickness estimating unit 54 gas hole optimizing unit

Claims (13)

A method of designing a gas hole for supplying gas into a processing container of a semiconductor manufacturing apparatus, comprising:
Based on a plurality of data sets in which the arrangement of the gas holes and the results of film formation actually formed by supplying gas from the gas holes in the arrangement of the gas holes are associated with each other, evaluation of film quality is performed. generating a model;
calculating a film quality evaluation value in the arrangement of the gas holes using the model, and optimizing the arrangement of the gas holes;
A method of designing a gas hole with In the step of generating the model, the film thickness model formed by the gas supplied from the gas holes is optimized for at least one or more holes in the longitudinal direction of the gas holes,
2. The method of designing a gas hole according to claim 1, wherein said model outputs an evaluation value of said film quality using said optimized film thickness model. 3. The method of designing a gas hole according to claim 2, wherein the model outputs the film thickness distribution in the longitudinal direction as the information on the film quality by summing the optimized film thickness models for each of the gas holes. . 4. The method of designing a gas hole according to claim 2, wherein in the step of generating the model, the film thickness model is optimized by black-box optimization. In the black box optimization, a first objective function for evaluating the film thickness model is input,
The first objective function is input with the arrangement of the gas holes, the film thickness when the film is formed in the gas holes in the arrangement, and a film thickness distribution calculation method using the film thickness model. 5. The method for designing a gas hole according to claim 4, wherein the film thickness model that has been transformed is output. The first objective function further includes process conditions including at least one of the type of gas, the pressure in the processing chamber, the temperature of the stage on which the substrate is placed, the plasma output, the film formation time, and the rotation speed of the turntable. 6. The method for designing a gas hole according to claim 5, wherein the input is . The film thickness model has a shape in which the film thickness is the largest at the center of the gas hole, and the film thickness decreases with increasing distance from the center of the gas hole,
7. The method of designing a gas hole according to claim 6, wherein said first objective function outputs at least one of magnitude, spread and skewness of said film thickness model. The semiconductor manufacturing apparatus has a rotary table for revolving the wafer to be deposited,
In the black box optimization, further, the domain and initial value of the size, spread, or skewness of the film thickness model are input,
8. The method of designing a gas hole according to claim 7, wherein in the defined area, the size of the film thickness model is defined to change with a constant gradient in the radial direction of the rotary table. In the step of optimizing the arrangement of the gas holes, the arrangement of the gas holes is changed by a tree structure search method, and the calculation of the evaluation value of the film quality output by the model is repeated, thereby optimizing the arrangement of the gas holes. The method for designing a gas hole according to claim 6, wherein the gas hole is optimized. In the tree structure search method, a second objective function for evaluating the arrangement of the gas holes is input,
The second objective function uses the optimized film thickness model to output the evaluation value of the film quality output by the model,
10. The gas hole design according to claim 9, wherein in the step of optimizing the arrangement of the gas holes, the optimized arrangement of the gas holes is determined by searching for the pattern of the gas holes having the higher evaluation value. Method. The method for designing gas holes according to any one of claims 1 to 10, wherein the design method determines shapes of the plurality of gas holes provided in a shower head used in the semiconductor manufacturing apparatus. In the step of optimizing the arrangement of the gas holes,
(a) a step of setting a reference pattern of the arrangement of the gas holes as a starting point for optimization;
(b) a step of assuming a pattern in which only one hole is changed in open/closed state from a reference pattern for all holes, and calculating the evaluation value of the film quality by the model;
(c) selecting N patterns for continuing the search based on the evaluation value of the film quality, until the depth of the tree structure search reaches a predetermined upper limit; Repeat the process to deepen the hierarchy of the tree structure, and further,
(d) Process of propagating the highest evaluation value for each hierarchy from the deepest hierarchy to the reference pattern
(e) selecting one change leading to the pattern with the highest evaluation value and updating the reference pattern;
12. The method for designing gas holes according to claim 10, wherein the steps (a) to (e) are repeated to determine the optimum arrangement of the gas holes. A gas hole design device for supplying gas into a processing container of a semiconductor manufacturing apparatus,
Based on a plurality of data sets in which the arrangement of the gas holes and the results of film formation actually formed by supplying gas from the gas holes in the arrangement of the gas holes are associated with each other, evaluation of film quality is performed. a model generator that generates a model;
a gas hole optimizing unit that uses the model to calculate an evaluation value of the film quality in the arrangement of the gas holes and optimizes the arrangement of the gas holes;
gas hole design device with

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