JP2022089151A - Film deposition apparatus and film deposition method - Google Patents

Abstract

To provide a technique capable of measuring a pressure in the vicinity of a substrate with high accuracy.SOLUTION: A film deposition apparatus includes: a treatment vessel capable of depressurizing an inside; a showerhead capable of supplying a gas into the treatment vessel and including a lower material having a plurality of gas holes and an upper material forming a diffusion space for diffusing the gas with the lower material; a mounting table arranged to face the showerhead and forming a treatment space with the showerhead; a lifting mechanism for lifting the mounting table; a cylindrical part penetrating the showerhead to communicate with the treatment space; and a pressure sensor air-tightly provided in the inside of the cylindrical part and for measuring a pressure of the treatment space.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to a film forming apparatus and a film forming method.

A film forming apparatus having a pressure sensor for measuring the pressure in the processing container is known (see, for example, Patent Documents 1 and 2). Further, there is known an atomic layer deposition (ALD) device that forms a diffusion space between a mounting table and a shower head in a processing container to improve gas displacement and perform processing (for example). , Patent Document 3).

Japanese Unexamined Patent Publication No. 2002-241943 Japanese Unexamined Patent Publication No. 2013-040398 JP-A-2015-175060

The present disclosure provides a technique capable of measuring the pressure in the vicinity of a substrate with high accuracy.

The film forming apparatus according to one aspect of the present disclosure is a processing container capable of depressurizing the inside, a shower head for supplying gas into the processing container, a lower member having a plurality of gas holes formed therein, and the lower member. A shower head including an upper member forming a diffusion space for diffusing the gas between the two, a mounting table arranged facing the shower head and forming a processing space between the shower head, and the above description. An elevating mechanism that raises and lowers the pedestal, a tubular portion that penetrates the shower head and communicates with the processing space, and a pressure sensor that is airtightly provided inside the tubular portion to measure the pressure in the processing space. Has.

According to the present disclosure, the pressure in the vicinity of the substrate can be measured with high accuracy.

Cross-sectional view showing an example of the film forming apparatus of the first embodiment Cross-sectional view showing the shower head of the film forming apparatus of FIG. A perspective view showing a shower head of the film forming apparatus of FIG. A perspective view showing a gas supply unit of the film forming apparatus of FIG. A vertical sectional view showing a gas supply unit of the film forming apparatus of FIG. A view of the shower head of the film forming apparatus of FIG. 1 as viewed from below. The figure which shows an example of the film formation method of 1st Embodiment Sectional drawing which shows the shower head of the film formation apparatus of 2nd Embodiment A plan view showing a shower head of the film forming apparatus of the second embodiment. The figure which shows the time change of the pressure in a processing vessel The figure which shows the time change of TiCl ₄ partial pressure The figure which shows the relationship between the step covering property and the TiCl ₄ partial pressure.

Hereinafter, non-limiting exemplary embodiments of the present disclosure will be described with reference to the accompanying drawings. In all the attached drawings, the same or corresponding members or parts are designated by the same or corresponding reference numerals, and duplicate description is omitted.

[First Embodiment]
(Film formation device)
An example of the film forming apparatus of the first embodiment will be described with reference to FIGS. 1 to 6. The film forming apparatus of the first embodiment is configured as an apparatus capable of forming a film by an atomic layer deposition (ALD) method.

The film forming apparatus 100 includes a processing container 1, a mounting table 2, a shower head 3, a gas supply unit 4, a gas introduction unit 5, an exhaust unit 6, a pressure measurement unit 7, a control unit 9, and the like.

The processing container 1 is a vacuum container capable of reducing the pressure inside. The processing container 1 is made of a metal such as aluminum and has a substantially cylindrical shape. The processing container 1 accommodates a semiconductor wafer (hereinafter referred to as “wafer W”), which is an example of a substrate. A carry-in outlet 11 for carrying in or out the wafer W is formed on the side wall of the processing container 1. The carry-in outlet 11 is opened and closed by the gate valve 12. An annular exhaust duct 13 having a rectangular cross section is provided on the main body of the processing container 1. A slit 13a is formed in the exhaust duct 13 along the inner peripheral surface. An exhaust port 13b is formed on the outer wall of the exhaust duct 13. A top plate member 14 is provided on the upper surface of the exhaust duct 13 so as to close the upper opening of the processing container 1. The space between the exhaust duct 13 and the top plate member 14 is hermetically sealed with a seal ring 15.

The mounting table 2 horizontally supports the wafer W in the processing container 1. The mounting table 2 has a disk shape larger than that of the wafer W, and is made of a ceramic material such as aluminum nitride (AlN) or a metal material such as aluminum or nickel alloy. A heater 21 for heating the wafer W is embedded in the mounting table 2. The heater 21 is supplied with power from a heater power supply (not shown) to generate heat. Then, the wafer W is controlled to a predetermined temperature by controlling the output of the heater 21 by the temperature signal of the thermocouple (not shown) provided near the upper surface of the mounting table 2. The mounting table 2 is provided with a cover member 22 formed of ceramics such as alumina so as to cover the outer peripheral region of the upper surface and the side surface.

The mounting table 2 is supported by the support member 23. The support member 23 extends from the center of the bottom surface of the mounting table 2 to the lower side of the processing container 1 through a hole formed in the bottom wall of the processing container 1, and its lower end is connected to the elevating mechanism 24. The mounting table 2 is moved up and down by the elevating mechanism 24 between the processing position shown in FIG. 1 and the transfer position where the wafer W can be transferred, which is indicated by the two-dot chain line below the processing position. A flange portion 25 is attached below the processing container 1 of the support member 23. A bellows 26 is provided between the bottom surface of the processing container 1 and the flange portion 25. The bellows 26 separates the atmosphere inside the processing container 1 from the outside air, and expands and contracts as the mounting table 2 moves up and down.

Near the bottom surface of the processing container 1, three wafer support pins 27 (only two are shown) are provided so as to project upward from the elevating plate. The wafer support pin 27 is moved up and down via the raising and lowering plate by the raising and lowering mechanism 28 provided below the processing container 1. The wafer support pin 27 is inserted into a through hole 2a provided in the mounting table 2 at the transport position so that the wafer support pin 27 can be recessed with respect to the upper surface of the mounting table 2. By raising and lowering the wafer support pin 27, the wafer W is transferred between the transfer robot (not shown) and the mounting table 2.

The shower head 3 supplies the processing gas into the processing container 1 in the form of a shower. The shower head 3 is made of, for example, a metal material and is arranged so as to face the mounting table 2. The shower head 3 has substantially the same diameter as the mounting table 2. The shower head 3 includes an upper member 31 and a lower member 32. The upper member 31 is fixed to the lower surface of the top plate member 14. The lower member 32 is connected below the upper member 31. A diffusion space 33 for diffusing gas is formed between the upper member 31 and the lower member 32. The diffusion space 33 is provided with a gas introduction path 36 so as to penetrate the top plate member 14 and the upper member 31. Gas is introduced into the gas introduction path 36 from the gas introduction unit 5 via the inlet block 55 described later. An annular protrusion 34 projecting downward is formed on the peripheral edge of the lower member 32. A large number of gas holes 35 are formed on the flat surface inside the annular protrusion 34 of the lower member 32. When the mounting table 2 is moved to the processing position, a narrow processing space 37 is formed between the mounting table 2 and the lower member 32, and the upper surface of the cover member 22 and the annular protrusion 34 are close to each other to form an annular gap 38. It is formed.

The large number of gas holes 35 include a plurality of inclined holes 35a and a plurality of untilted holes 35b. The plurality of inclined holes 35a are arranged around the cylindrical portion 71 described later, and are inclined toward the center of the tubular portion 71 from the side of the diffusion space 33 toward the side of the processing space 37. It is preferable that the plurality of inclined holes 35a are arranged so that the inclination angle becomes larger toward the center of the tubular portion 71. As a result, the gas is also discharged below the cylindrical portion 71 in which the gas hole 35 is not arranged, so that the in-plane uniformity is improved. The plurality of untilted holes 35b are arranged around the plurality of inclined holes 35a and do not have an inclination from the side of the diffusion space 33 toward the side of the processing space 37.

For example, eight gas supply units 4 are provided in the diffusion space 33. The eight gas supply units 4 are arranged so as to surround the center of the shower head 3 in an annular shape at equal intervals. The number of gas supply units 4 provided in the diffusion space 33 is not limited to eight. For example, if at least two, preferably three or more gas supply units 4 are provided at positions separated from each other on the ring surrounding the center of the shower head 3, gas is uniformly supplied into the shower head 3 in a short time. can. The shape of the ring provided with the plurality of gas supply units 4 is not limited to the annular ring, and may be arranged on, for example, a square ring.

As shown in FIGS. 4 and 5, each gas supply unit 4 includes a pedestal portion 43 fastened to the upper member 31 and a head portion 41 provided on the lower surface side of the pedestal portion 43 and having a hollow inside. ing. A recess into which the pedestal portion 43 is inserted is formed on the lower surface of the upper member 31, and when the pedestal portion 43 is fitted into the recess, the head portion 41 moves from the lower surface of the upper member 31 into the diffusion space 33. It will be in a protruding state.

A screw hole 43a is formed in the pedestal portion 43, and the pedestal portion 43 is formed with respect to the upper member 31 by screwing the screw 43b into the screw hole 43a and the screw hole formed in the recess on the upper member 31 side. To be concluded.

If the processing gas invades between the pedestal portion 43 and the upper member 31 to form a film and the pedestal portion 43 and the upper member 31 are fixed, particles may be generated when the gas supply portion 4 is removed. .. Therefore, the pedestal portion 43 of this example has a configuration capable of suppressing the generation of such particles.

As shown in FIG. 5, the pedestal portion 43 is formed to be one size smaller than the recess on the upper member 31 side, and is formed between the outer peripheral surface of the pedestal portion 43 and the inner peripheral surface of the recess on the upper member 31 side. For example, a gap 31a of about 0.1 to 1 mm is formed. Further, a flat ring-shaped protrusion 43c projecting toward the upper side projects from the upper end portion of the screw hole 43a in the pedestal portion 43. The pedestal portion 43 comes into contact with the upper member 31 through the contact surface on the upper surface side of the protrusion 43c, and is about the same as the side surface side between the upper surface of the pedestal portion 43 and the lower surface of the recess on the upper member 31 side. A gap 31a is formed.

Further, the pedestal portion 43 is formed with a gas passage 43d communicating with the gas introduction passage 36 formed in the upper member 31 so as to penetrate the pedestal portion 43 in the vertical direction. An O-ring 43e, which is a packing member that airtightly connects the gas introduction path 36 and the gas path 43d, is provided around the opening on the upper end side of the gas path 43d.

As a result, the portion that comes into contact with the upper member 31 is limited to the contact surface on the upper surface side of the protrusion 43c and the O-ring 43e, and in the other portions, a relatively large gap 31a is formed between the pedestal portion 43 and the upper member 31. Will be done. Therefore, even if the processing gas enters the pedestal portion 43 and the upper member 31 to form a film, the pedestal portion 43 and the upper member 31 are unlikely to adhere to each other. As a result, it is possible to suppress the generation of particles when the gas supply unit 4 is removed.

Further, the portion in contact with the upper member 31 is limited to the contact surface on the upper surface side of the protrusion 43c and the O-ring 43e, and these contact portions are provided on the upper surface side of the pedestal portion 43 far from the entry position. There is. Therefore, it is difficult for the reaction gas to enter between the contact surface of the protrusion 43c or the O-ring 43e and the upper member 31. Moreover, even if it enters, its area is small. As a result, it is possible to suppress the generation of particles when the gas supply unit 4 is removed.

The head portion 41 is provided so as to cover the opening on the lower end side of the gas passage 43d from the lower surface side of the pedestal portion 43, and is, for example, a flat cylindrical cover having a diameter of 8 to 20 mm, for example, 20 mm. A plurality of gas discharge ports 42 provided at intervals along the circumferential direction are formed on the side surface of the head portion 41. For example, three or more gas discharge ports 42 are preferably provided for each head portion 41, and 12 gas discharge ports 42 are provided in this example. Further, since the lower surface of the head portion 41 is closed and the gas discharge port 42 is not provided, the gas flowing into the head portion 41 is uniformly spread laterally from each gas discharge port 42. It is discharged.

As described above, the gas supply unit 4 is configured to be able to spread the gas uniformly in the circumferential direction. The gas discharged from the gas discharge port 42 of the gas supply unit 4 is sufficiently spread in the shower head 3 and then supplied to the processing space 37 through the gas hole 35. As a result, the gas is uniformly supplied to the surface of the wafer W on the mounting table 2.

The gas introduction unit 5 supplies various gases to the shower head 3. The gas introduction unit 5 includes a raw material gas supply unit 51, a first purge gas supply unit 52, a nitride gas supply unit 53, a second purge gas supply unit 54, and an inlet block 55.

The raw material gas supply unit 51 includes a raw material gas source 51S, a gas supply line 51L, a flow rate controller 51M, a storage tank 51T, and a valve 51V. The raw material gas source 51S supplies titanium chloride gas (TiCl ₄ ), which is an example of the raw material gas, into the processing container 1 via the gas supply line 51L. The gas supply line 51L is a line extending from the raw material gas source 51S. The gas supply line 51L is connected to the inlet block 55. A flow rate controller 51M, a storage tank 51T, and a valve 51V are interposed in the gas supply line 51L in order from the raw material gas source 51S side. The flow rate controller 51M controls the flow rate of TiCl ₄ flowing through the gas supply line 51L. The flow rate controller 51M is, for example, a mass flow controller (MFC). The storage tank 51T temporarily stores TiCl ₄ . Since the storage tank 51T is provided, a large flow rate of TiCl ₄ can be supplied into the processing container 1 in a short time. The storage tank 51T is also referred to as a buffer tank or a fill tank. The valve 51V is a valve for switching between supply and stop of gas at the time of ALD. The valve 51V is, for example, an ALD valve that can be opened and closed at high speed. The ALD valve is preferably openable and closable at intervals of 0.01 seconds to 1.0 seconds.

The first purge gas supply unit 52 includes a purge gas source 52S, a gas supply line 52L, a flow rate controller 52M, and a valve 52V. The purge gas source 52S supplies nitrogen gas (N ₂ ), which is an example of purge gas, into the processing container 1 via the gas supply line 52L. The gas supply line 52L is a line extending from the purge gas source 52S. The gas supply line 52L is connected to the gas supply line 51L. A flow rate controller 52M and a valve 52V are interposed in the gas supply line 52L in order from the purge gas source 52S side. The flow rate controller 52M controls the flow rate of N ₂ flowing through the gas supply line 52L. The flow rate controller 52M is, for example, a mass flow rate controller. The valve 52V is a valve for switching between supply and stop of gas at the time of ALD. The valve 52V is, for example, an ALD valve that can be opened and closed at high speed. The ALD valve is preferably openable and closable at intervals of 0.01 seconds to 1.0 seconds.

The nitriding gas supply unit 53 includes a nitriding gas source 53S, a gas supply line 53L, a flow rate controller 53M, a storage tank 53T, and a valve 53V. The nitriding gas source 53S supplies ammonia gas (NH ₃ ), which is an example of nitriding gas, into the processing container 1 via the gas supply line 53L. The gas supply line 53L is a line extending from the nitride gas source 53S. The gas supply line 53L is connected to the inlet block 55. A flow rate controller 53M, a storage tank 53T, and a valve 53V are interposed in the gas supply line 53L in order from the nitride gas source 53S side. The flow rate controller 53M controls the flow rate of NH ₃ flowing through the gas supply line 53L. The flow rate controller 53M is, for example, a mass flow controller. The storage tank 53T temporarily stores NH ₃ . Since the storage tank 53T is provided, a large flow rate of NH ₃ can be supplied into the processing container 1 in a short time. The storage tank 53T is also referred to as a buffer tank or a fill tank. The valve 53V is a valve for switching between supply and stop of gas at the time of ALD. The valve 53V is, for example, an ALD valve that can be opened and closed at high speed. The ALD valve is preferably openable and closable at intervals of 0.01 seconds to 1.0 seconds.

The second purge gas supply unit 54 includes a purge gas source 54S, a gas supply line 54L, a flow rate controller 54M, and a valve 54V. The purge gas source 54S supplies nitrogen gas (N ₂ ), which is an example of purge gas, into the processing container 1 via the gas supply line 54L. The gas supply line 54L is a line extending from the purge gas source 54S. The gas supply line 54L is connected to the gas supply line 53L. A flow rate controller 54M and a valve 54V are interposed in the gas supply line 54L in order from the purge gas source 54S side. The flow rate controller 54M controls the flow rate of N ₂ flowing through the gas supply line 54L. The flow rate controller 54M is, for example, a mass flow rate controller. The valve 54V is a valve for switching between supply and stop of gas at the time of ALD. The valve 54V is, for example, an ALD valve that can be opened and closed at high speed. The ALD valve is preferably openable and closable at intervals of 0.01 seconds to 1.0 seconds.

The inlet block 55 has a cylindrical shape with a hollow inside, and is provided on the top plate member 14. The inlet block 55 is arranged at the center of the top plate member 14. A gas flow path 55a is formed inside the inlet block 55. The gas flow path 55a communicates with the gas supply lines 51L and 53L and the gas introduction path 36, and supplies the gas supplied from the gas supply lines 51L and 53L to the gas introduction path 36.

The exhaust unit 6 decompresses the inside of the processing container 1 by exhausting the inside of the processing container 1. The exhaust unit 6 includes an exhaust pipe 61, a pressure controller 62, and a vacuum pump 63. The exhaust pipe 61 is connected to the exhaust port 13b. The pressure controller 62 is interposed in the exhaust pipe 61. The pressure controller 62 may be a valve that controls conductance in the exhaust pipe 61, for example, by adjusting the opening degree. The vacuum pump 63 is interposed in the exhaust pipe 61.

The pressure measuring unit 7 includes a tubular unit 71 and a pressure sensor 72. The tubular portion 71 has a cylindrical shape with a hollow inside. The tubular portion 71 penetrates the top plate member 14 and the shower head 3 in the thickness direction and communicates with the processing space 37. The tubular portion 71 is provided at the center of the top plate member 14. As a result, in a plan view, the hollow portion of the tubular portion 71 and the hollow portion of the inlet block 55 communicate with each other. The pressure sensor 72 is airtightly provided inside the tubular portion 71, and measures the pressure in the processing space 37. The pressure sensor 72 transmits the measured value to the control unit 9.

The control unit 9 implements the film forming method described later by controlling the operation of each part of the film forming apparatus 100. The control unit 9 may be, for example, a computer or the like. The computer program that operates each part of the film forming apparatus 100 is stored in the storage medium. The storage medium may be, for example, a flexible disk, a compact disk, a hard disk, a flash memory, a DVD, or the like.

By the way, conventionally, in a decompression CVD device and a decompression ALD device, in order to measure the pressure in the processing container, a pressure sensor such as a capacitance manometer is installed on the side wall of the processing container to measure the pressure. However, in the ALD device such as the above-mentioned film forming apparatus 100, a narrow processing space 37 is formed between the mounting table 2 and the shower head 3 in the processing container 1 to improve the gas replaceability and perform the processing. , The accurate pressure of the processing space 37 cannot be measured. Therefore, in order to secure the process performance, it is necessary to change the conditions and try the process many times, which makes it difficult to secure the process performance.

On the other hand, according to the film forming apparatus 100 of the embodiment, the tubular portion 71 penetrating the shower head 3 and communicating with the processing space 37 and the tubular portion 71 are airtightly provided inside the processing space 37. It has a pressure sensor 72 and a pressure sensor 72 for measuring the pressure of the cylinder. As a result, the pressure in the processing space 37, that is, the pressure in the vicinity of the wafer W can be measured with high accuracy.

(Film formation method)
An example of the film forming method of the embodiment will be described with reference to FIG. 7. The film forming method of the embodiment includes a carry-in step, a film forming step, and a carry-out step.

In the carry-in process, the wafer W is carried into the processing container 1. In the carry-in process, the gate valve 12 is opened with the mounting table 2 lowered to the transport position, and the wafer W is carried into the processing container 1 through the carry-in outlet 11 by a transfer robot (not shown), and the heater 21 is used. It is placed on a mounting table 2 heated to a predetermined temperature. Subsequently, the mounting table 2 is raised to the processing position, and the pressure inside the processing container 1 is reduced to a predetermined pressure.

The film forming step is performed after the carry-in step. In the film forming step, a series of operations including a TiCl ₄ supply step, a TiCl ₄ purge step, an NH ₃ supply step, and an NH ₃ purge step are set as one cycle, and the number of cycles is controlled to control the number of cycles of titanium nitride (TiN) having a desired film thickness. ) Form a film.

The TiCl ₄ supply step is a step of supplying TiCl ₄ to the processing space 37. In the TiCl ₄ supply step, first, the valves 52V and 54V are opened, and _N2 gas is continuously supplied from the purge gas sources 52S and 54S via the gas supply lines 52L and 54L. Further, by opening the valve 51V, TiCl ₄ is supplied from the raw material gas supply unit 51 to the processing space 37 via the gas supply line 51L. At this time, TiCl ₄ is temporarily stored in the storage tank 51T and then supplied into the processing container 1. Further, in the TiCl ₄ supply step, the control unit 9 controls the inside of the processing space 37 to a desired pressure by controlling the pressure controller 62 based on the measured value of the pressure sensor 72.

The TiCl ₄ purge step is a step of purging the surplus TiCl ₄ and the like in the processing space 37. In the TiCl ₄ purge step, the valve 51V is closed to stop the supply of TiCl ₄ from the gas supply line 51L while the supply of _N2 gas is continued through the gas supply lines 52L and 54L.

The NH ₃ supply step is a step of supplying NH ₃ gas to the processing space 37. In the NH ₃ supply step, the valve 53V is opened while the supply of N ₂ gas via the gas supply lines 52L and 54L is continued. As a result, _NH3 gas is supplied from the nitride gas source 53S to the processing space 37 via the gas supply line 53L. At this time, NH ₃ is temporarily stored in the storage tank 53T and then supplied into the processing container 1. The NH ₃ supply step reduces TiCl ₄ adsorbed on the wafer W. The flow rate of NH ₃ at this time can be set to an amount that sufficiently causes a reduction reaction. Further, in the NH ₃ supply step, the control unit 9 controls the inside of the processing space 37 to a desired pressure by controlling the pressure controller 62 based on the measured value of the pressure sensor 72.

The NH ₃ purge step is a step of purging the surplus NH ₃ in the processing space 37. In the NH ₃ purge step, the valve 53V is closed and the supply of NH ₃ from the gas supply line 53L is stopped while the supply of N ₂ gas through the gas supply lines 52L and 54L is continued.

A series of operations including the TiCl ₄ supply step, the TiCl ₄ purge step, the NH ₃ supply step, and the NH ₃ purge step described above are set as one cycle, and the number of cycles is controlled to form a TiN film having a desired film thickness. It can be a film.

The carry-out step is executed after the film forming step is completed. In the carry-out step, the gate valve 12 is opened with the mounting table 2 lowered to the transport position, and the wafer W is carried out of the processing container 1 through the carry-in / out port 11 by a transport robot (not shown).

If there is a wafer W to be processed next, the wafer W is returned to the carry-in step again after the carry-out step, and the film forming step and the carry-out step are executed. As a result, a TiN film having a desired film thickness can be formed on the next wafer W.

According to the film forming method of the embodiment described above, the pressure controller 62 is based on the measured value of the pressure sensor 72 airtightly provided inside the tubular portion 71 that penetrates the shower head 3 and communicates with the processing space 37. By controlling the pressure inside the processing space 37, the pressure is controlled to a desired level. As a result, the pressure in the vicinity of the wafer W can be controlled with high accuracy, so that the desired process performance can be easily realized.

In the example shown in FIG. 2, a dead space 73 exists between the pressure sensor 72 and the surface of the shower head 3 facing the wafer W. However, from the viewpoint of suppressing gas retention / residual, the pressure sensor 72 It is preferable to arrange the pressure sensor 72 so that the surface of the shower head 3 facing the wafer W is flush with each other.

[Second Embodiment]
An example of the film forming apparatus of the second embodiment will be described with reference to FIGS. 8 and 9. FIG. 8 is a schematic cross-sectional view showing an example of a shower head of the film forming apparatus of the second embodiment. FIG. 9 is a schematic plan view showing an example of a shower head of the film forming apparatus of the second embodiment. Note that FIG. 8 shows a cross section cut along the alternate long and short dash line VIII-VIII in FIG.

As shown in FIGS. 8 and 9, the film forming apparatus 100A of the second embodiment is provided with valves 51V to 54V on the inlet block 55, and the film forming apparatus 100 of the first embodiment is provided. Is different. The other configurations may be the same as those of the film forming apparatus 100 of the first embodiment.

According to the film forming apparatus 100A of the second embodiment, since the valves 51V to 54V are provided in the vicinity of the processing space 37, after the valves 51V to 54V are opened, until the processing gas is supplied to the processing space 37. Time lag (time delay) can be shortened. Furthermore, since the distance from the valves 51V to 54V to the processing space 37 can be shortened, the amount of gas remaining in the gas flow path on the secondary side of the valves 51V to 54V after the valves 51V to 54V are closed can be reduced. can. As a result, gas switching in the ALD process can be performed smoothly in a short time.

〔Example〕
In the examples, the partial pressures of TiCl ₄ when the supply timing of TiCl ₄ was changed when the TiN film was formed by the film forming method of the above-described embodiment were compared.

In the ALD process, the film is formed while switching the gas and the pressure in the processing container 1 at high speed, and it is necessary to supply the gas while the pressure in the processing container 1 fluctuates (pulsates). ), The pressure of the raw material gas (TiCl ₄ ) also tends to be unsteady.

FIG. 10 is a diagram showing the time change of the pressure in the processing container 1. In FIG. 10, the horizontal axis indicates the time [seconds], and the vertical axis indicates the pressure [Torr] in the processing container 1. FIG. 11 is a diagram showing the time change of the TiCl ₄ partial pressure. In FIG. 11, the horizontal axis represents time [seconds], and the vertical axis represents TiCl ₄ -partial pressure [Torr]. In FIGS. 10 and 11, the solid line, the broken line, and the alternate long and short dash line are the processing containers when the pressures in the processing container 1 are 1.5 Torr (200 Pa), 3.0 Torr (400 Pa), and 5.0 Torr (667 Pa), respectively. The result when TiCl ₄ was supplied in 1 is shown.

As shown in FIGS. 10 and 11, when the raw material gas (TiCl ₄ ) is supplied while the pressure in the processing container 1 fluctuates, the partial pressure of the raw material gas (TiCl ₄ ) monitors the pressure in the processing container 1. It turns out that it is difficult to find it uniquely just by doing it. Therefore, it is considered important to install a pressure sensor on the shower head and measure the pressure in the vicinity of the substrate in order to know the TiCl _quaternary pressure.

FIG. 12 is a diagram showing the relationship between the step covering property and the TiCl ₄ partial pressure. In FIG. 12, the horizontal axis shows the step covering property [%] when a TiN film is formed on a pattern substrate having a pattern including recesses, and the vertical axis shows the TiCl ₄ partial pressure [Torr].

As shown in FIG. 12, it can be seen that there is a positive correlation between the step coverage and the TiCl ₄ partial pressure. From this result, it can be said that the step covering property can be improved by increasing the TiCl ₄ partial pressure.

From the above results, it can be said that it is important to install a pressure sensor on the shower head and measure the pressure in the vicinity of the substrate in order to grasp the process performance (for example, step coverage).

The embodiments disclosed this time should be considered to be exemplary and not restrictive in all respects. The above embodiments may be omitted, replaced or modified in various forms without departing from the scope of the appended claims and their gist.

In the above embodiment, the case where the tubular portion and the pressure sensor are provided in the center of the shower head has been described, but the present disclosure is not limited to this. For example, the tubular portion and the pressure sensor may be provided in a place other than the center of the shower head. Further, for example, the tubular portion and the pressure sensor may be provided at a plurality of positions in the plane of the shower head. This makes it possible to measure the pressure distribution in the substrate surface.

In the above embodiment, the ALD apparatus for forming a TiN film by alternately and intermittently supplying TiCl ₄ gas and NH ₃ gas has been described, but the present disclosure is not limited to this, and other gases are used. The present disclosure can also be applied to an ALD device that forms a film on another film.

1 Processing container 2 Mounting table 24 Elevating mechanism 3 Shower head 31 Upper member 32 Lower member 33 Diffusion space 35 Gas hole 37 Processing space 71 Cylindrical part 72 Pressure sensor 100, 100A Film deposition equipment

Claims (8)

A processing container that can reduce the pressure inside,
A shower head that supplies gas into the processing container, and includes a lower member having a plurality of gas holes formed therein and an upper member forming a diffusion space for diffusing the gas between the lower members. When,
A mounting table that is arranged to face the shower head and forms a processing space between the shower head and the shower head.
An elevating mechanism that raises and lowers the above-mentioned stand,
A tubular portion that penetrates the shower head and communicates with the processing space,
A pressure sensor that is airtightly provided inside the tubular portion and measures the pressure in the processing space,
A film forming apparatus. The tubular portion is provided in the center of the shower head.
The film forming apparatus according to claim 1. The plurality of gas holes include a plurality of inclined holes inclined toward the center of the tubular portion from the side of the diffusion space toward the side of the processing space.
The film forming apparatus according to claim 1 or 2. The plurality of inclined holes have a larger inclination angle as they are closer to the center of the cylindrical portion.
The film forming apparatus according to claim 3. The plurality of gas holes include a plurality of unsloping holes having no inclination from the side of the diffusion space toward the side of the processing space.
The film forming apparatus according to any one of claims 1 to 4. A pressure controller that controls the pressure inside the processing container,
A control unit that controls the pressure controller based on the measured value of the pressure sensor,
Have,
The film forming apparatus according to any one of claims 1 to 5. It is provided on the upper member so as to surround the tubular portion, and has a cylindrical inlet block for introducing the gas into the diffusion space.
The film forming apparatus according to any one of claims 1 to 6. A processing container that can reduce the pressure inside,
A shower head that supplies gas into the processing container, and includes a lower member having a plurality of gas holes formed therein and an upper member forming a diffusion space for diffusing the gas between the lower members. When,
A mounting table that is arranged to face the shower head and forms a processing space between the shower head and the shower head.
An elevating mechanism that raises and lowers the above-mentioned stand,
A tubular portion that penetrates the shower head and communicates with the processing space,
A pressure sensor that is airtightly provided inside the tubular portion and measures the pressure in the processing space,
It is a film forming method in a film forming apparatus having
The pressure in the processing container is controlled based on the measured value of the pressure sensor.
Film formation method.

Images