阅读说明：本技术 原料供给装置和成膜装置 (Raw material supply device and film forming device ) 是由 木元大寿 渡边纪之 成嶋健索 关户幸一 川口拓哉 于 2021-04-07 设计创作，主要内容包括：本发明提供能够使成膜开始时的原料气体的流量在短时间内变得稳定的技术。本发明的一方式的原料供给装置包括：向处理容器内供给原料气体的原料供给通路；设置于所述原料供给通路的阀；检测所述原料供给通路内的压力的压力传感器；与所述原料供给通路连接,对所述原料供给通路内的所述原料气体进行排气的原料排气通路；设置于所述原料排气通路,通过调节开度来控制所述原料供给通路内的压力的开度调节机构；和基于所述压力传感器的检测值来调节所述开度调节机构的所述开度的控制部。(The invention provides a technique capable of stabilizing the flow rate of a raw material gas at the start of film formation in a short time. A raw material supply apparatus according to an aspect of the present invention includes: a source material supply passage for supplying a source material gas into the processing chamber; a valve provided in the raw material supply passage; a pressure sensor for detecting a pressure in the raw material supply passage; a raw material exhaust passage connected to the raw material supply passage and configured to exhaust the raw material gas in the raw material supply passage; an opening degree adjusting mechanism provided in the raw material exhaust passage and configured to adjust an opening degree to control a pressure in the raw material supply passage; and a control unit that adjusts the opening degree of the opening degree adjustment mechanism based on a detection value of the pressure sensor.)

1. A raw material supply apparatus, comprising:

a source material supply passage for supplying a source material gas into the processing chamber;

a valve provided in the raw material supply passage;

a pressure sensor for detecting a pressure in the raw material supply passage;

a raw material exhaust passage connected to the raw material supply passage and configured to exhaust the raw material gas in the raw material supply passage;

an opening degree adjusting mechanism provided in the raw material exhaust passage and configured to adjust an opening degree to control a pressure in the raw material supply passage; and

a control unit that adjusts the opening degree of the opening degree adjustment mechanism based on a detection value of the pressure sensor.

2. The material supply apparatus according to claim 1, wherein:

further comprises a storage tank provided in the raw material supply passage for storing the raw material gas.

3. The raw material supply apparatus according to claim 1 or 2, characterized in that:

the control unit is configured to be capable of adjusting the opening degree of the opening degree adjustment mechanism so that the detection value of the pressure sensor becomes stable at a target value while the raw material gas is discharged through the raw material exhaust passage.

4. The material supply apparatus according to claim 3, wherein:

the target value is determined based on a detection value of the pressure sensor when the source gas is supplied into the processing container and the processing is performed in the processing container.

5. The raw material supply apparatus according to any one of claims 1 to 4, characterized in that:

the controller is configured to be able to adjust the opening of the opening adjustment mechanism in a state where the substrate is accommodated in the processing container.

6. The raw material supply apparatus according to any one of claims 1 to 5, characterized in that:

the opening degree adjusting mechanism includes:

a pneumatic valve for opening and closing the valve body by using air pressure; and

an electro-pneumatic regulator for regulating the air pressure introduced into the air-operated valve,

the control unit is configured to control the electro-pneumatic regulator to adjust the opening degree of the pneumatic valve.

7. The material supply apparatus according to claim 6, wherein:

the pneumatic valve is an ALD valve.

8. The raw material supply apparatus according to any one of claims 1 to 7, characterized in that:

the valve is an ALD valve.

9. The raw material supply apparatus according to any one of claims 1 to 8, characterized in that:

the raw material gas is generated by sublimation of a solid raw material or evaporation of a liquid raw material.

10. A film forming apparatus, comprising:

a processing vessel; and

a raw material supply device for supplying a raw material gas into the processing container,

the raw material supply device includes:

a source material supply passage configured to supply the source gas into the processing chamber;

a valve provided in the raw material supply passage;

a pressure sensor for detecting a pressure in the raw material supply passage;

a raw material exhaust passage connected to the raw material supply passage and configured to exhaust the raw material gas in the raw material supply passage;

an opening degree adjusting mechanism provided in the raw material exhaust passage and configured to adjust an opening degree to control a pressure in the raw material supply passage; and

a control unit that adjusts the opening degree of the opening degree adjustment mechanism based on a detection value of the pressure sensor.

Technical Field

The present invention relates to a raw material supply apparatus and a film forming apparatus.

Background

There is known a technique of intermittently exhausting a source gas without supplying the source gas into a process chamber before film formation when the source gas is intermittently supplied into the process chamber to form a film (for example, see patent document 1).

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2019-52346.

Disclosure of Invention

Problems to be solved by the invention

The invention provides a technique capable of stabilizing the flow rate of a raw material gas at the start of film formation in a short time.

Means for solving the problems

A raw material supply apparatus according to an aspect of the present invention includes: a source material supply passage for supplying a source material gas into the processing chamber; a valve provided in the raw material supply passage; a pressure sensor for detecting a pressure in the raw material supply passage; a raw material exhaust passage connected to the raw material supply passage and configured to exhaust the raw material gas in the raw material supply passage; an opening degree adjusting mechanism provided in the raw material exhaust passage and configured to adjust an opening degree to control a pressure in the raw material supply passage; and a control unit that adjusts the opening degree of the opening degree adjustment mechanism based on a detection value of the pressure sensor.

Effects of the invention

According to the present invention, the flow rate of the source gas at the start of film formation can be stabilized in a short time.

Drawings

Fig. 1 is a schematic diagram showing an example of a film forming apparatus including a raw material supply apparatus according to an embodiment.

Fig. 2 is a diagram illustrating an example of a film formation method according to the embodiment.

Fig. 3 is a diagram showing an example of changes in the tank pressure in the initial flow rate stabilization step and the film formation step.

Fig. 4 is a diagram showing an example of a gas supply flow in the film forming step.

Description of the reference numerals

1 treatment vessel

61 gas supply line

73 valve

80 storage tank

80a pressure sensor

104 raw material exhaust passage

105 opening degree adjusting mechanism

120 valve opening degree control part

Pt target value

W wafer

Detailed Description

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

[ film Forming apparatus ]

A film deposition apparatus including a raw material supply apparatus according to an embodiment will be described with reference to fig. 1. Fig. 1 is a schematic diagram showing an example of a film forming apparatus including a raw material supply apparatus according to an embodiment. The film forming apparatus according to the embodiment is configured as an apparatus capable of performing film formation by an Atomic Layer Deposition (ALD) method and film formation by a Chemical Vapor Deposition (CVD) method.

The film deposition apparatus includes a processing chamber 1, a stage 2, a shower head 3, an exhaust unit 4, a gas supply unit 5, a control unit 6, a valve opening control unit 120, and the like.

The processing container 1 is made of metal such as aluminum and has a substantially cylindrical shape. The processing container 1 can accommodate semiconductor wafers (hereinafter referred to as "wafers W") as an example of substrates. A carry-in/out port 11 for carrying in and out the wafer W is formed in a side wall of the processing container 1. The feed outlet 11 is opened and closed by a gate valve 12. An annular exhaust duct 13 having a rectangular cross section is provided in the main body of the processing container 1. A slit 13a is formed along the inner circumferential surface of the exhaust duct 13. An exhaust port 13b is formed in the outer wall of the exhaust duct 13. A ceiling wall 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 exhaust duct 13 is hermetically sealed from the top wall 14 by a sealing 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 the wafer W and is made of a ceramic material such as aluminum nitride (AlN) or a metal material such as aluminum or a nickel alloy. A heater 21 for heating the wafer W is embedded in the mounting table 2. The heater 21 generates heat when supplied with power from a heater power supply (not shown). The output of the heater 21 is controlled by a temperature signal of a thermocouple (not shown) provided in the vicinity of the upper surface of the stage 2, thereby controlling the wafer W to a predetermined temperature. The mounting table 2 is provided with a covering member 22 made of ceramic such as alumina so as to cover an outer peripheral region and a side surface of an upper surface.

The mounting table 2 is supported by the support member 23. The support member 23 extends downward of the processing container 1 from the center of the bottom surface of the mounting table 2 through a hole formed in the bottom wall of the processing container 1, and the lower end thereof is connected to the elevating mechanism 24. The mounting table 2 is moved up and down by the lift mechanism 24 between the processing position shown in fig. 1 and a position below which the wafer W can be carried, which is indicated by a two-dot chain line. A flange 25 is attached to the support member 23 below the processing container 1. A bellows 26 is provided between the bottom surface of the processing container 1 and the flange 25. The bellows 26 separates the atmosphere in the processing container 1 from the outside air, and expands and contracts in accordance with the up-and-down operation of the stage 2.

In the vicinity of the bottom surface of the processing container 1, 3 (only 2 shown in the figure) wafer support pins 27 are provided so as to protrude upward from the elevating plate 27 a. The wafer support pins 27 are lifted and lowered by a lift mechanism 28 provided below the processing container 1 via a lift plate 27 a. The wafer support pin 27 is inserted through the through hole 2a provided in the mounting table 2 at the transfer position and is capable of protruding and retracting with respect to the upper surface of the mounting table 2. By raising and lowering the wafer support pins 27, the wafer W can be transferred between the transfer arm (not shown) and the mounting table 2.

The shower head 3 supplies the processing gas into the processing chamber 1 in a shower shape. The shower head 3 is formed of, for example, a metal material, and is disposed 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 a main body portion 31 and a shower plate 32. The body portion 31 is fixed to the lower surface of the top wall 14. The shower plate 32 is connected below the main body 31. A gas diffusion space 33 is formed between the main body 31 and the shower plate 32. The gas diffusion space 33 is provided with a gas introduction hole 36 penetrating the center of the top wall 14 and the body 31. An annular projection 34 projecting downward is formed on the peripheral edge of the shower plate 32. A large number of gas release holes 35 are formed in the flat surface of the shower plate 32 on the inner side of the annular projection 34.

When the stage 2 is moved to the processing position, a processing space 37 is formed between the stage 2 and the shower plate 32, and the upper surface of the cover member 22 is brought close to the annular protrusion 34 to form an annular gap 38.

The exhaust unit 4 exhausts the inside of the processing container 1. The exhaust unit 4 includes an exhaust pipe 41 and an exhaust mechanism 42. The exhaust pipe 41 is connected to the exhaust port 13 b. The exhaust mechanism 42 is connected to the exhaust pipe 41 and includes a vacuum pump, a pressure control valve, and the like. The exhaust mechanism 42 exhausts the gas in the processing chamber 1 through the exhaust pipe 13 and the exhaust pipe 41.

The gas supply unit 5 supplies various gases to the shower head 3. The gas supply unit 5 includes a source gas supply mechanism 51, a 1 st reducing gas supply source 52, a 2 nd reducing gas supply source 53, a 1 st purge gas supply source 54, a 2 nd purge gas supply source 55, and a 3 rd reducing gas supply source 56.

The raw material gas supply mechanism 51 supplies tungsten hexachloride (WCl) as an example of a raw material gas into the processing container 1 through the gas supply line 61₆) A gas. The gas supply line 61 is a raw material supply passage extending from the raw material gas supply mechanism 51.

The gas supply line 61 is provided with a valve 96a, a valve 96b, a flow meter 97, a reservoir tank 80, and a valve 73 in this order from the raw material gas supply mechanism 51 side.

The valves 96a and 96b are provided in the vicinity of the film formation material tank 91 in the gas supply line 61.

The flow meter 97 detects WCl flowing in the gas supply line 61₆The flow rate of the gas. The Flow Meter 97 is, for example, a Mass Flow Meter (MFM).

The storage tank 80 temporarily stores WCl₆A gas. By providing the storage tank 80, a large flow rate of WCl can be supplied in a short time₆Gas is supplied into the processing container 1. The storage tank 80 is also referred to as a buffer tank, a filling tank. The storage tank 80 is provided with a pressure sensor 80a that detects the internal pressure. The pressure sensor 80a detects the pressure in the storage tank 80 and sends the detected value to the valve opening control unit 120. The pressure sensor 80a is, for example, a capacitance manometer.

The valve 73 is a valve for switching supply and stop of gas in ALD. The valve 73 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 0.5 seconds or less, more preferably at intervals of 0.01 seconds or less.

The source gas supply mechanism 51 includes a film formation source tank 91. The film-forming material tank 91 stores WCl as a solid material which is solid at normal temperature₆. A heater 91a is provided around the film formation material tank 91. The heater 91a supplies WCl in the film forming raw material tank 91₆Heating to a suitable temperature to bring the WCl to₆And (4) sublimating. When WCl₆Upon sublimation, WCl is formed₆A gas. A gas supply line 61 is inserted into the film formation material tank 91 from above.

One end of a carrier gas pipe 92 is inserted into the film-forming material tank 91 from above in the material gas supply mechanism 51. The other end of the carrier gas pipe 92 is connected to a carrier gas supply source 93. The carrier gas supply source 93 supplies nitrogen (N) as an example of the carrier gas to the carrier gas pipe 92₂) And (4) qi.

The carrier gas pipe 92 is provided with a flow rate controller 94, a valve 95a, and a valve 95b in this order from the carrier gas supply source 93 side. The flow rate controller 94 controls the flow of N in the carrier gas pipe 92₂The flow rate of the gas. The flow controller 94 is, for exampleMass Flow controllers (MFC: Mass Flow Controller).

A bypass pipe 98 is provided to connect a position between the valves 95a and 95b in the carrier gas pipe 92 and a position between the valves 96a and 96b in the gas supply line 61. The bypass pipe 98 is a carrier N supplied from the carrier gas supply source 93 to the carrier gas pipe 92₂The gas is supplied to the piping of the gas supply line 61 without passing through the film formation material tank 91. The bypass pipe 98 is provided with a valve 99. N supplied from carrier gas supply source 93 by closing valves 95b, 96a and opening valves 95a, 99, 96b₂The gas is supplied to the gas supply line 61 through the carrier gas pipe 92 and the bypass pipe 98. This allows the gas supply line 61 to be purged.

N, which is an example of a diluent gas, is supplied at a point between the valve 96b and the flow meter 97 in the gas supply line 61₂A diluent gas supply line 100 for the gas. The other end of the diluent gas supply line 100 is provided with N₂A diluent gas supply 101 as a gas supply source. The diluent gas supply line 100 is provided with a flow rate controller 102 and a valve 103 in this order from the diluent gas supply source 101 side. The flow controller 102 controls N flowing in the diluent gas supply line 100₂The flow rate of the gas. The flow controller 102 is, for example, a Mass Flow Controller (MFC).

One end of the raw material exhaust passage 104 is connected between the storage tank 80 and the valve 73 in the gas supply line 61. The other end of the raw material exhaust passage 104 is connected to the exhaust pipe 41. Thereby, the inside of the storage tank 80 can be exhausted through the raw material exhaust passage 104 by the exhaust mechanism 42. The raw material exhaust passage 104 is also referred to as an exhaust Line (exhaust Line).

The raw material exhaust passage 104 is provided with an opening degree adjustment mechanism 105 and a valve 106 in this order from the gas supply line 61 side.

The opening degree adjusting means 105 controls the conductance of the raw material exhaust passage 104 by adjusting the opening degree, and controls the WCl flowing through the raw material exhaust passage 104₆The flow rate of the gas. Thereby, the pressure in the gas supply line 61 including the storage tank 80 is controlled. The opening degree of the opening degree adjusting mechanism 105 is controlled by a valve opening degree control unit 120.The opening degree adjustment mechanism 105 includes a pneumatic valve and an electro-pneumatic regulator. The pneumatic valve controls the conductance of the raw material exhaust passage 104 by opening and closing a valve body by air pressure. Pneumatic valves are also known as air operated valves, pneumatic valves. The electro-pneumatic regulator controls the air pressure to be introduced into the air-operated valve in proportion to the electric signal output by the valve opening degree control section 120. When the opening degree adjustment mechanism 105 includes the air-operated valve and the electro-pneumatic regulator, the opening and closing of the valve can be performed in a short time, and thus the delay time (delay time) associated with the opening and closing of the valve can be shortened. In addition, from the viewpoint of shortening the delay time in particular, the air-operated valve is preferably an ALD valve that can be opened and closed at high speed. The ALD valve is preferably openable and closable at intervals of 0.5 seconds or less, more preferably at intervals of 0.01 seconds or less. The opening degree adjustment mechanism 105 may be configured to include a motor that opens and closes the valve body by rotating the handle, and a motor that rotates the handle of the manual valve.

The valve 106 is a valve for opening and closing the raw material exhaust passage. The raw material exhaust passage 104 is exhausted by the exhaust mechanism 42 by opening the valve 106.

The 1 st reducing gas supply source 52 supplies hydrogen (H) as an example of a reducing gas into the processing container 1 through the gas supply line 62₂) And (4) qi. The gas supply line 62 is a line extending from the 1 st reducing gas supply source 52. The gas supply line 61 and the gas supply line 62 merge together in a confluence pipe 72, and the confluence pipe 72 is connected to the gas introduction hole 36. The gas supply line 62 is provided with a flow rate controller 82, a storage tank 81, and a valve 74 in this order from the 1 st reducing gas supply source 52 side.

The flow controller 82 controls the H flowing in the gas supply line 62₂The flow rate of the gas. The flow controller 82 is, for example, a Mass Flow Controller (MFC).

The storage tank 81 temporarily stores H₂A gas. By providing the storage tank 81, a large flow rate of H can be supplied in a short time₂Gas is supplied into the processing container 1. The storage tank 81 is also called a buffer tank and a filling tank.

The valve 74 is a valve for switching supply and stop of gas when ALD is performed. The valve 74 is, for example, an ALD valve that can be opened and closed at high speed. The ALD valve is preferably capable of opening and closing at intervals of 0.01 second to 1.0 second.

The 2 nd reducing gas supply source 53 supplies H, which is an example of a reducing gas, into the processing container 1 through the gas supply line 63₂A gas. The gas supply line 63 is a line extending from the 2 nd reducing gas supply source 53. The gas supply line 63 is provided with a flow rate controller 83, a valve 88 and a valve 75 in this order from the 2 nd reducing gas supply source 53 side. The flow controller 83 controls the H flowing in the gas supply line 63₂The flow rate of the gas. The flow controller 83 is, for example, a Mass Flow Controller (MFC). The valves 88 and 74 are valves for switching supply and stop of gas when ALD is performed. The valves 88 and 74 are ALD valves that can be opened and closed at high speed, for example. The ALD valve is preferably capable of opening and closing at intervals of 0.01 second to 1.0 second.

The 1 st purge gas supply source 54 supplies N as an example of a purge gas into the process container 1 through the gas supply line 64₂A gas. The gas supply line 64 is a line for supplying N to the gas supply line 61 side extending from the 1 st purge gas supply source 54₂A pipeline of gas. The gas supply line 64 is branched to constantly supply N during the film formation by the ALD method₂Gas supply line 66 for gas and N supply only during the purge step₂A gas supply line 67 for gas. The gas supply line 66 and the gas supply line 67 are connected to the 1 st connection line 70, and the 1 st connection line 70 is connected to the gas supply line 61. The gas supply line 66 is provided with a flow rate controller 84 and a valve 76 in this order from the 1 st purge gas supply source 54 side. The gas supply line 67 is provided with a flow rate controller 85 and a valve 77 in this order from the 1 st purge gas supply source 54 side. Flow controllers 84, 85 control N flowing in gas supply lines 66, 67₂The flow rate of the gas. The flow controllers 84, 85 are, for example, Mass Flow Controllers (MFCs). The valves 76 and 77 are valves for switching supply and stop of gas in ALD. The valves 76 and 77 are ALD valves that can be opened and closed at high speed, for example. The ALD valve is preferably capable of opening and closing at intervals of 0.01 to 1.0 second.

The 2 nd purge gas supply source 55 supplies a purge gas as a purge gas into the process container 1 through the gas supply line 65Example N₂A gas. The gas supply line 65 is a line for supplying N to the gas supply line 62 side extending from the 2 nd purge gas supply source 55₂A pipeline of gas. The gas supply line 65 is branched to always supply N in the film formation by the ALD method₂Gas supply line 68 for gas and N supply only during the purge step₂A gas supply line 69 for gas. The gas supply line 68 and the gas supply line 69 are connected to a 2 nd connection line 71, and the 2 nd connection line 71 is connected to the gas supply line 62. The gas supply line 68 is provided with a flow rate controller 86 and a valve 78 in this order from the 2 nd purge gas supply source 55 side. The gas supply line 69 is provided with a flow rate controller 87 and a valve 79 in this order from the 2 nd purge gas supply source 55 side. Flow controllers 86, 87 control N flowing in gas supply lines 68, 69₂The flow rate of the gas. The flow controllers 86, 87 are, for example, Mass Flow Controllers (MFCs). The valves 78 and 79 are valves for switching supply and stop of gas in ALD. The valves 78 and 79 are ALD valves that can be opened and closed at high speed, for example. The ALD valve is preferably capable of opening and closing at intervals of 0.01 second to 1.0 second.

The 3 rd reducing gas supply source 56 supplies monosilane (SiH) as an example of a reducing gas into the process container 1 through the gas supply line 63a₄) A gas. A gas supply line 63a extends from the 3 rd reducing gas supply source 56 and is connected to the gas supply line 63. The gas supply line 63a is provided with a flow rate controller 83a and a valve 88a in this order from the 3 rd reducing gas supply source 56 side. The flow rate controller 83a controls the SiH flowing in the gas supply line 63a₄The flow rate of the gas. The flow controller 83a is, for example, a Mass Flow Controller (MFC).

The control section 6 includes a microprocessor (computer) processing controller, a user interface, and a storage section, which are provided to control each constituent section, specifically, a valve, a power supply, a heater, a pump, and the like. The process controller is electrically connected to and controlled by each component of the film deposition apparatus. The user interface is connected to the process controller, and includes a keyboard for an operator to input commands for managing the respective components of the film deposition apparatus, a display for visually displaying the operating conditions of the respective components of the film deposition apparatus, and the like. The storage unit is also connected to the process controller. The storage unit stores: a control program for realizing various processes implemented in the film formation apparatus under the control of the process controller; a control program for causing each component of the film formation apparatus to perform a predetermined process according to the process conditions, i.e., a process recipe, various databases, and the like. The processing recipe is stored in a storage medium (not shown) in the storage unit. The storage medium may be, for example, a hard disk, a CDROM, a DVD, a semiconductor memory. Further, the processing scheme may also be appropriately transmitted from other apparatuses via, for example, a dedicated line. If necessary, a predetermined process recipe is called from the storage unit in accordance with an instruction from the user interface or the like and executed by the process controller, whereby a desired process in the film deposition apparatus is performed under the control of the process controller.

The valve opening degree control unit 120 adjusts the opening degree of the opening degree adjusting mechanism 105 based on the detection value of the pressure sensor 80a, that is, the pressure in the storage tank 80 (hereinafter, also referred to as "tank pressure"). For example, the valve opening degree control unit 120 adjusts the opening degree of the opening degree adjustment mechanism 105 so that WCl is not supplied into the processing container 1₆Gas, while sending WCl through the material exhaust passage 104₆The gas is discharged so that the detection value of the pressure sensor 80a becomes stable (becomes a stable state) while reaching the target value. The target value is based on, for example, supplying WCl into the processing container 1₆The gas is determined based on the value detected by the pressure sensor 80a when the gas is processed in the processing container 1.

[ film Forming method ]

Referring to fig. 1 to 4, a film forming method according to an embodiment will be described by taking as an example a case where a tungsten film is formed on a wafer W by an ALD method using the film forming apparatus shown in fig. 1. Fig. 2 is a diagram illustrating an example of a film formation method according to the embodiment.

As shown in fig. 2, the film forming method of the embodiment includes a feeding step, an initial flow rate stabilizing step, a film forming step, and a feeding step. In the following description, at a time before the start of the carrying-in process, the valves 73 to 79, 88a, and 99 of the film forming apparatus are closed, the valves 95a, 95b, 96a, 96b, 103, and 106 are opened, and the opening degree adjustment mechanism 105 is "fully opened".

In the loading step, the wafer W is loaded into the processing container 1. In the loading step, the gate valve 12 is opened with the stage 2 lowered to the transfer position, and the wafer W is loaded into the processing container 1 through the loading outlet 11 by a transfer arm (not shown) and placed on the stage 2 heated to a predetermined temperature by the heater 21. Next, the mounting table 2 is raised to the processing position, and the pressure in the processing container 1 is reduced to a predetermined pressure.

The initial flow rate stabilization step is performed after the end of the feed step. In the initial flow rate stabilizing step, the temperature of the wafer W on the mounting table 2 is stabilized. For example, N is supplied from the 1 st purge gas supply source 54 and the 2 nd purge gas supply source 55 into the process container 1 by opening the valves 76 and 78₂The gas is pressurized to stabilize the temperature of the wafer W on the mounting table 2.

In the initial flow rate stabilization step, the opening degree of the opening degree adjustment mechanism 105 is adjusted so that WCl is not supplied into the processing container 1₆Gas is supplied to WCl through the material exhaust passage 104₆The pressure in the storage tank 80 is stabilized (becomes a stable state) while the gas is exhausted to reach a target value. The pressure in the storage tank 80 is detected by a pressure sensor 80 a.

Fig. 3 is a diagram showing an example of changes in the tank pressure in the initial flow rate stabilization step and the film formation step. In fig. 3, the horizontal axis represents time, and the vertical axis represents tank pressure. In the initial flow rate stabilization step, at time t in fig. 3₁The valve opening degree control unit 120 controls the opening degree of the opening degree adjustment mechanism 105 from "off" to "full on". Thereby, WCl in the storage tank 80₆The gas is exhausted through the raw material exhaust passage 104 by the exhaust mechanism 42, and the tank pressure is reduced.

Then, after the tank pressure becomes lower than the target value Pt, at time t from fig. 3, for example₁Time t after elapse of a predetermined time₂The valve opening degree control unit 120 adjusts the opening degree of the opening degree adjustment mechanism 105 between "open" and "full open" such that the tank pressure reaches the target value Pt and becomes stable.

The target value Pt is based on, for example, the supply of WCl into the processing vessel 1₆Gas is inThe pot pressure at the time of performing the treatment in the treatment vessel 1. In the case of the first initial flow rate stabilization process, the target value Pt is determined based on, for example, the tank pressure in a simulation process performed before the initial flow rate stabilization process. In the dummy process, for example, WCl is supplied into the process container 1 in the same gas supply flow as in the film forming process described later in a state where the dummy wafer is placed on the mounting table 2 in the process container 1₆And (5) a gas step. When the initial flow rate stabilization step is performed for the second time or later, the target value Pt is preferably a target value set in the previous film formation step, for example. This reduces wafer-to-wafer variation (W2W).

The target value Pt is preferably set to a value at which WCl is supplied into the processing vessel 1, as shown in FIG. 3, for example₆Maximum tank pressure P of gas when processing is performed in the processing container 1_maxA pressure of less than a prescribed pressure. The predetermined pressure is determined based on the delay time associated with switching from the initial flow rate stabilization step to the film formation step, i.e., the supply of WCl₆The delay time due to the opening/closing of the opening degree adjustment mechanism 105 and the valve 73, which occurs when the target gas is switched from the raw material exhaust passage 104 to the gas supply line 61. However, the valve 73 and the opening degree adjustment mechanism 105 may be ALD valves, and the target value Pt may be equal to the target value Pt for supplying WCl into the processing container 1 when the delay time is substantially absent₆Maximum tank pressure P of gas when processing is performed in the processing container 1_maxThe same pressure.

In this manner, in the initial flow rate stabilization step, the opening degree of the opening degree adjustment mechanism 105 is adjusted so that the tank pressure becomes stable at the target value Pt in parallel with the stabilization of the temperature of the wafer W on the mounting table 2. This can avoid a decrease in productivity due to the addition of the process of stabilizing the tank pressure at the target value Pt.

The film forming process is executed after the initial flow stabilization process is completed. In the film formation step, a film formation process is performed to form a tungsten film on the wafer W. After the tank pressure is stabilized at the target value Pt in the initial flow rate stabilization step, for example, at time t in FIG. 3₃The valve opening control part 120 adjusts the opening degreeThe opening degree of the mechanism 105 is controlled to be "fully closed", and the control unit 6 opens the valve 73. Whereby the WCl stored in the storage tank 80₆The gas is supplied into the processing chamber 1 without being exhausted through the source material exhaust passage 104, and the tank pressure is lowered. In this case, it is preferable to synchronize the opening degree adjustment mechanism 105 with the opening and closing timing of the valve 73. This can reduce the variation in the tank pressure when switching from the initial flow rate stabilization step to the film formation step. For example, by using ALD valves as the opening degree adjustment mechanism 105 and the valve 73, the opening degree adjustment mechanism 105 and the valve 73 can be synchronized in opening and closing timing. After a predetermined time T has elapsed from the valve 73 being opened_openAt time t₄The control unit 6 closes the valve 73. Thereby, the WCl in the processing container 1 is caused₆The supply of gas is stopped, WCl₆The gas is stored in the storage tank 80 to increase the tank pressure. Further, a time T is specified_openIs a time specified by a processing recipe or the like.

Then, a predetermined time T elapses after the valve 73 is closed_closeAt time t₅The control unit 6 opens the valve 73. Whereby the WCl stored in the storage tank 80₆The gas is supplied into the processing container 1 to reduce the tank pressure. Further, a time T is specified_closeIs a time determined by a processing scheme or the like.

Thereafter, the WCl is intermittently supplied into the processing container 1 by repeating opening and closing of the valve 73₆A gas. In fig. 3, time t₆、t₈、t₁₀Indicates the timing of closing the valve 73, time t₇、t₉Indicating the timing of opening the valve 73.

However, since the film forming step is performed after the initial flow rate stabilizing step, the tank pressure is stabilized at the target value Pt at the start of the film forming step. Thereby, at the start of film formation (time t)₃) The pot pressure of (a) becomes equal to that during film formation (time t)₅、t₇、t₉) Is approximately the same value.

In the film forming step, a target value to be used in the next initial flow rate stabilizing step is set based on the tank pressure when the opening and closing of the valve 73 are repeated. For example, the later stage of the opening/closing of the valve 73 is repeatedA maximum tank pressure P of a predetermined number of times (e.g., 10 times)_maxThe target value used in the next initial flow rate stabilization step is set.

Fig. 4 is a diagram showing an example of a gas supply flow in the film forming step. As shown in fig. 4, in the film formation step, a series of operations including the raw material gas supply step, the 1 st purge step, the reducing gas supply step, and the 2 nd purge step was set to 1 cycle, and the number of cycles was controlled to form a tungsten film having a desired film thickness.

The raw material gas supply step is to supply WCl as raw material gas₆And supplying the gas to the processing space 37. In the raw material gas supply step, first, N is continuously supplied from the 1 st purge gas supply source 54 and the 2 nd purge gas supply source 55 via the gas supply line 66 and the gas supply line 68 with the valves 76 and 78 opened₂A gas. Further, by opening the valve 73, WCl is supplied from the source gas supply mechanism 51 through the gas supply line 61₆Gas is supplied to the process space 37. In the raw material gas supply step, H as the reducing gas may be supplied through the gas supply line 63 extending from the 2 nd reducing gas supply source 53₂Gas is supplied into the processing container 1. By contacting with WCl in the raw material gas supply step₆The gas is simultaneously supplied with a reducing gas, WCl to be supplied₆The gas is activated, so that a film forming reaction is likely to occur in the subsequent reducing gas supply step. Therefore, the high step coverage can be maintained, and the deposition film thickness per 1 cycle can be increased to increase the film formation speed. The flow rate of the reducing gas may be such that the CVD reaction does not occur in the raw material gas supply step.

The 1 st purge step is to purge the remaining WCl of the process volume 37₆And (4) purging gas and the like. In the 1 st purge step, N is continuously supplied via the gas supply line 66 and the gas supply line 68₂In the gas state, valve 73 is closed to stop WCl₆And (3) supplying gas. Further, N is also supplied from the gas supply line 67 and the gas supply line 69 by opening the valves 77, 79₂Gas (purge N)₂Gas) andwith large flow rates of N₂Gas to the remaining WCl of the processing space 37₆The gas or the like is purged. However, the sweep N may not be supplied₂A gas.

The reducing gas supply step is to supply H as the reducing gas₂And supplying the gas to the processing space 37. In the reducing gas supply step, the valves 77, 79 are closed to stop N from the gas supply line 67 and the gas supply line 69₂And (3) supplying gas. Further, N is continuously supplied via the gas supply line 66 and the gas supply line 68₂In the gas state, the valve 74 is opened. Thereby, H as a reducing gas is supplied from the 1 st reducing gas supply source 52 through the gas supply line 62₂Gas is supplied to the process space 37. At this time, H₂The gas is temporarily stored in the storage tank 81 and then supplied into the processing container 1. WCl adsorbed on wafer W by the reducing gas supply step₆The gas is reduced. At this time H₂The flow rate of the gas can be an amount that allows the reduction reaction to sufficiently occur.

The 2 nd purge step is to purge the remaining H of the process space 37₂And (4) purging the gas. In the 2 nd purge step, N is continuously supplied via the gas supply line 66 and the gas supply line 68₂In the gas state, the valve 74 is closed to stop the supply of H from the gas supply line 62₂And (3) supplying gas. Further, N is also supplied from the gas supply line 67 and the gas supply line 69 by opening the valves 77 and 79₂Gas (purge N)₂Gas) using a large flow of N₂Gas, to the remaining H of the processing space 37₂The gas is purged. However, the sweep N may not be supplied₂A gas.

A series of operations including the source gas supply step, the 1 st purge step, the reducing gas supply step, and the 2 nd purge step described above is set as 1 cycle, and the number of cycles is controlled, whereby a tungsten film having a desired film thickness can be formed.

The feeding step is executed after the film forming step is completed. In the unloading step, the gate valve 12 is opened with the stage 2 lowered to the transfer position, and the wafer W is unloaded out of the processing container 1 through the loading port 11 by a transfer arm (not shown).

When the wafer W to be processed is subsequently present, the wafer W is returned to the carry-in step after the carry-out step, and the initial flow rate stabilization step, the film formation step, and the carry-out step are performed. This enables the formation of a tungsten film having a desired thickness on the next wafer W.

As described above, according to the embodiment, WCl is supplied into the processing container 1₆When a tungsten film is formed by a gas, the opening of the opening adjusting mechanism 105 is adjusted so as to be opposite to WCl through the raw material exhaust passage 104 before film formation₆The gas is exhausted while the tank pressure is stabilized to a target value. The target value is based on the supply of WCl into the processing container 1₆The gas is determined by the tank pressure at the time of performing the treatment in the treatment vessel 1. Thus, the tank pressure at the start of film formation and the tank pressure during film formation are substantially the same. In other words, the tank pressure at the start of film formation can be made equal to the tank pressure during film formation. Therefore, the difference (variation) between the pot pressure immediately after the start of film formation and the pot pressure during the subsequent period during film formation is reduced. As a result, WCl immediately after film formation can be reduced₆Gas flow rate and WCl during the subsequent period of film formation₆The difference (unevenness) between the flow rates of the gases. Thus, according to the embodiment, WCl at the start of film formation can be set₆The flow rate of the gas becomes stable in a short time.

In the embodiment, when the tungsten film is formed continuously on the plurality of wafers W, for example, when the initial flow rate stabilizing step is performed after the second time, the target value can be a target value set in the previous film forming step. This makes it possible to match the tank pressure at the start of film formation with the tank pressure in the latest film formation step. As a result, WCl at the start of film formation can be controlled₆Gas flow rate and WCl in recent film forming process₆The flow rates of the gases are uniform, so that the WCl between the wafers W can be reduced₆Unevenness in the flow rate of the gas. In particular, by setting the target value used in the initial flow rate stabilization step based on the average value of the tank pressures of the predetermined number of times in the later stage in the latest film formation step, the tank pressure at the start of film formation and the maximum value can be setThe pot pressures at the end of the next film forming step were the same. As a result, WCl between wafers W can be reduced₆Unevenness in the flow rate of the gas.

In the embodiment, the pressure in the storage tank 80 is controlled by controlling the conductance of the raw material exhaust passage 104 by adjusting the opening degree of the opening degree adjusting mechanism 105. Therefore, the adjustment range of the pressure in the storage tank 80 is large. Further, since the pressure is adjusted without introducing gas into the material exhaust passage 104 from the outside, the influence of disturbance of the gas flow in the material exhaust passage 104 can be reduced.

The embodiments disclosed herein are illustrative and not restrictive in all respects. The above-described embodiments may be omitted, replaced, or changed in various ways without departing from the spirit and scope of the appended claims.

In the above-described embodiment, the case where the initial flow rate stabilization step is started after the end of the carrying-in step is exemplified, but the present invention is not limited thereto. The timing of starting the initial flow rate stabilization step may be before starting the film formation step. For example, the initial flow rate stabilization process may be started before the start of the delivery process, may be started simultaneously with the start of the delivery process, or may be started in the middle of the delivery process. In this way, by starting the initial flow rate stabilization step before the end of the feeding step, the feeding step and the initial flow rate stabilization step can be performed simultaneously, and the time until the start of the film formation step can be shortened, thereby improving productivity.

In the above-described embodiment, the case where the valve opening degree control unit 120 adjusts the opening degree of the opening degree adjustment mechanism 105 has been described as an example, but the present invention is not limited to this. For example, the opening degree of the opening degree adjustment mechanism 105 may be adjusted by the control unit 6 instead of the valve opening degree control unit 120.

In the above-described embodiment, the case where the valve opening degree control unit 120 adjusts the opening degree of the opening degree adjustment mechanism 105 based on the pressure in the reservoir tank 80, which is the pressure in the gas supply line 61, has been described as an example, but the present invention is not limited thereto. For example, when the storage tank 80 is not provided in the gas supply line 61, a pressure sensor may be provided in the gas supply line 61, and the valve opening degree control unit 120 may adjust the opening degree adjustment mechanism 105 based on a detection value of the pressure sensor.

In the above embodiment, WCl is used as the raw material gas₆The case where the gas is used to form the tungsten film has been described as an example, but the present invention is not limited to this. For example, WCl can be used₅Other tungsten chloride gases, e.g. gas, even using WCl₅Gas also reacts with WCl₆The gas behaves approximately the same. Using WCl₅In the case of gas, WCl which is solid at normal temperature is used as a film forming raw material₅. The present invention can also be applied to, for example, a case where a molybdenum film is formed using a molybdenum chloride gas or a case where a tantalum film is formed using a tantalum chloride gas. In these cases, molybdenum chloride or tantalum chloride, which is solid at room temperature, can be used as the film forming raw material. In the above-described embodiment, the solid raw material is sublimated to generate the raw material gas, but the liquid raw material may be evaporated to generate the raw material gas.

In the above embodiment, H is used as the reducing gas₂The case of gas has been described as an example, but the present invention is not limited to this. As reducing gases, other than H₂Besides gases, SiH can also be used, for example₄Gas, B₂H₆Gas, NH₃Gases, and the like. H may also be supplied₂Gas, SiH₄Gas, B₂H₆Gas and NH₃More than 2 of the gas. Alternatively, other reducing gases may be used, e.g. PH₃Gas, SiH₂Cl₂A gas. From the viewpoint of reducing impurities in the film to obtain a low resistance value, it is preferable to use H₂A gas. Further, as the purge gas and the carrier gas, N can be replaced by₂As the gas, other inert gases such as Ar gas are used.

In the above-described embodiments, the semiconductor wafer is described as an example of the substrate, but the semiconductor wafer may be a silicon wafer or a compound semiconductor wafer such as GaAs, SiC, or GaN. The substrate is not limited to a semiconductor wafer, and the present invention can be applied to a glass substrate, a ceramic substrate, and the like used for an FPD (flat panel display) such as a liquid crystal display device.