Method for cleaning components of plasma processing apparatus

This application claims priority to Japanese Patent Application No. 2018-005002 filed on Jan. 16, 2018, the entire contents of which are incorporated herein by reference.

The present disclosure relates to a method for cleaning components of a plasma processing apparatus.

In manufacturing electronic devices, substrate treatment is performed. The substrate treatment is performed in an inner space of a chamber of a plasma processing apparatus. When the substrate treatment is performed, a deposit is formed on surfaces of components of the plasma processing apparatus. The surface that defines the inner space includes the surfaces of the components. The components include the chamber itself, the components provided in the chamber, and the like. The deposit formed on the surfaces of the components should be removed.

Japanese Patent Application Publication No. 2013-175797 discloses therein a technique for removing a fluorocarbon film, which is one of the deposits generated during the substrate treatment, by plasma cleaning. In the plasma cleaning, plasma of a cleaning gas is generated, and the fluorocarbon film is removed by active species such as ions and/or radicals in the plasma.

The deposit may be made of materials that are not easily removed by the plasma cleaning (e.g., metal-containing material). Further, the deposit may be formed on a surface that defines a space where the plasma of the cleaning gas hardly reaches. Therefore, there is a demand for a method for cleaning components of a plasma processing apparatus, which is different from the plasma cleaning.

In accordance with an aspect, there is provided a method for cleaning a component of a plasma processing apparatus, a surface of the component being included in a surface that defines an inner space formed in a chamber of the plasma processing apparatus. The cleaning method comprises: (i) forming a film on the surface of the component by supplying a first gas and a second gas into the inner space, wherein a compound forming the film is generated by polymerization of a first compound contained in the first gas and a second compound contained in the second gas, the first compound being isocyanate and the second compound being amine or a compound having a hydroxyl group; and (ii) removing, after substrate treatment is performed in the inner space, a deposit formed on the film during the substrate treatment by heating the component so that depolymerization of the compound forming the film occurs.

The objects and features of the present disclosure will become apparent from the following description of embodiments, given in conjunction with the accompanying drawings, in which:

FIG. 1 is a flowchart showing a cleaning method according to an embodiment;

FIG. 2 schematically shows an example of a plasma processing apparatus to which the cleaning method shown in FIG. 1 can be applied;

FIG. 3 shows a state of the plasma processing apparatus after execution of a step ST 1 of the cleaning method shown in FIG. 1 ;

FIG. 4 shows a state of the plasma processing apparatus after execution of a step SP of the cleaning method shown in FIG. 1 ;

FIG. 5 shows a state of the plasma processing apparatus after execution of a step ST 2 of the cleaning method shown in FIG. 1 ;

FIG. 6 shows a state of the plasma processing apparatus after execution of a step STa of the cleaning method shown in FIG. 1 ;

FIG. 7 shows a state of the plasma processing apparatus after execution of a step STb of the cleaning method shown in FIG. 1 ;

FIG. 8 shows a state of the plasma processing apparatus after execution of the step SP of the cleaning method shown in FIG. 1 ;

FIG. 9 shows the state of the plasma processing apparatus after execution of a step STc of the cleaning method shown in FIG. 1 ;

FIG. 10 is a flowchart showing an example of substrate treatment in the step SP of the cleaning method shown in FIG. 1 ;

FIG. 11 is a partially enlarged cross sectional view of an example of a substrate to which an example of the substrate treatment in the step SP shown in FIG. 10 can be applied;

FIGS. 12A to 12D are partially enlarged cross sectional views of the substrate obtained during the execution of the example of substrate treatment in the step SP;

FIG. 12E is a partially enlarged cross sectional view of the substrate after execution of the example of the substrate treatment in the step SP;

FIG. 13 is a flowchart showing an example of a step STR shown in FIG. 10 ;

FIG. 14A is a partially enlarged cross sectional view of a substrate after film formation in the step STR; and

FIG. 14B is a partially enlarged cross sectional view of the substrate after etching of a film in the step STR.

Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. Like reference numerals will be given to like or corresponding parts throughout the drawings.

FIG. 1 is a flowchart showing a cleaning method according to an embodiment. The cleaning method (hereinafter, referred to as “method MT”) shown in FIG. 1 is performed to clean components of a plasma processing apparatus. FIG. 2 schematically shows an example of a plasma processing apparatus to which the cleaning method shown in FIG. 1 can be applied. A plasma processing apparatus 10 shown in FIG. 2 is a capacitively coupled plasma processing apparatus.

The plasma processing apparatus 10 includes a chamber 11 . The chamber 11 has an inner space S therein. The inner space S includes a first space S 1 and a second space S 2 . The chamber 11 includes a chamber body 12 . The chamber body 12 has a substantially cylindrical shape. The chamber body 12 has the inner space S therein. The chamber body 12 is made of, e.g., aluminum. The chamber body 12 is connected to a ground potential. A corrosion resistant film is formed on an inner wall surface of the chamber body 12 , i.e., on a surface of the chamber body 12 which defines the inner space S. This film may be a film formed by anodic oxidation treatment, or a ceramic film made of yttrium oxide. A heater HT 12 may be provided in the chamber body 12 , e.g., in a sidewall of the chamber body 12 . The heater HT 12 generates heat when power is supplied from a heater controller HC 12 to the heater HT 12 .

A passage 12 p is formed in the sidewall of the chamber body 12 . The substrate W is transferred between the inner space S and the outside of the chamber 11 through the passage 12 p . The passage 12 p can be opened and closed by a gate valve 12 g . The gate valve 12 g is provided along the sidewall of the chamber body 12 .

A partition wall 14 is provided in the inner space S. The partition wall 14 extends on the boundary between the first space S 1 and the second space S 2 . The first space S 1 and the second space S 2 communicate with each other through a plurality of through-holes formed in the partition wall 14 . The partition wall 14 may be formed by forming a corrosion resistant film on a surface of an aluminum base. The corrosion resistant film may be a film formed by anodic oxidation treatment, or a ceramic film made of yttrium oxide. A heater HT 14 may be provided in the partition wall 14 . The heater HT 14 generates heat when power is supplied from a heater controller HC 14 to the heater HT 14 .

In one embodiment, the partition wall 14 includes a shield portion 14 a and a baffle plate 14 b . The shield portion 14 a has a substantially cylindrical shape. The shield portion 14 a extends in a vertical direction along the sidewall of the chamber body 12 in the inner space S. The shield portion 14 a is separated from the sidewall of the chamber body 12 . An upper end of the shield portion 14 a extends to an upper portion of the chamber 11 and is fixed to the upper portion. In the plasma processing apparatus 10 , substrate treatment is performed in the first space S 1 . During the substrate treatment, by-products such as reaction products and the like are generated. The amount of the by-products adhered to the surface of the chamber body 12 is reduced by the shield portion 14 a.

The baffle plate 14 b extends in a direction orthogonal to the shield portion 14 a . The baffle plate 14 b extends between the shield portion 14 a and a supporting table to be described later. The above-described through-holes of the partition wall 14 are formed in the baffle plate 14 b . The shield portion 14 a and the baffle plate 14 b may be formed as one unit or may be separable from each other.

In the inner space S, a supporting part 15 extends upward from a bottom portion of the chamber body 12 . The supporting part 15 has a substantially cylindrical shape and is made of an insulating material such as quartz. A supporting table 16 is mounted on the supporting part 15 . The supporting table 16 is supported by the supporting part 15 . The supporting table 16 is configured to support the substrate W in the first space S 1 . The supporting table 16 includes a lower electrode 18 and an electrostatic chuck 20 . The supporting table 16 may further include an electrode plate 21 . The electrode plate 21 is made of a conductive material such as aluminum or the like and has a substantially disc shape. The lower electrode 18 is provided on the electrode plate 21 . The lower electrode 18 is made of a conductive material such as aluminum or the like and has a substantially disc shape. The lower electrode 18 is electrically connected to the electrode plate 21 .

A flow path 18 f is provided in the lower electrode 18 . The flow path 18 f is a channel for a heat exchange medium. As for the heat exchange medium, a liquid coolant or a coolant (e.g., Freon) for cooling the lower electrode 18 by vaporization thereof is used. The heat exchange medium is supplied to the flow path 18 f from a chiller unit provided outside the chamber body 12 through a line 22 a . The heat exchange medium supplied to the flow path 18 f is returned to the chiller unit through a line 22 b . In this manner, the heat exchange medium is supplied to the flow path 18 f and circulates between the flow path 18 f and the chiller unit.

The electrostatic chuck 20 is provided on the lower electrode 18 . The electrostatic chuck 20 includes a main body and an electrode. The main body of the electrostatic chuck 20 is made of a dielectric material and has a substantially disc shape. The electrode of the electrostatic chuck 20 is a film-shaped electrode and is provided in the main body of the electrostatic chuck 20 . A DC power supply 23 is electrically connected to the electrodes of the electrostatic chuck 20 via a switch 24 . When a voltage is applied from the DC power supply 23 to the electrode of the electrostatic chuck 20 , an electrostatic attractive force is generated between the substrate W mounted on the electrostatic chuck 20 and the electrostatic chuck 20 . Due to the electrostatic attractive force thus generated, the substrate W is attracted to and held on the electrostatic chuck 20 .

The plasma processing apparatus 10 further includes a gas supply line 25 . A heat transfer gas, e.g., He gas, is supplied through the gas supply line 25 from a gas supply unit to a gap between an upper surface of the electrostatic chuck 20 and a backside (bottom surface) of the substrate W.

One or more heaters HT 20 (e.g., resistance heating elements) may be provided in the electrostatic chuck 20 . Power is supplied from a heater controller HC 20 to one or more heaters HT 20 . A high frequency filter FT 20 may be provided between one or more heaters HT 20 and the heater controller HC 20 to prevent the high frequency from flowing into the heater controller HC 20 . When the heaters HT 20 are provided in the electrostatic chuck 20 , temperatures of a plurality of regions of the electrostatic chuck 20 can be individually controlled by controlling the power supplied from the heater controller HC 20 to the heaters HT 20 . Accordingly, it is possible to control temperature distribution in the plane of the electrostatic chuck 20 (i.e., in the plane of the substrate W).

A focus ring FR is disposed on an outer peripheral region of the electrostatic chuck 20 . The focus ring FR has a substantially annular plate shape. The focus ring FR is made of a silicon-containing material such as silicon, quartz, or silicon carbide. The focus ring FR is disposed to surround the edge of the substrate W.

A tubular member 26 extends upward from the bottom portion of the chamber body 12 . The tubular member 26 extends along an outer periphery of the supporting part 15 . The tubular member 26 is made of a conductor and has a substantially cylindrical shape. The tubular member 26 is connected to the ground potential. A corrosion resistant film may be formed on a surface of the tubular member 26 . The corrosion resistance film may be a film formed by anodic oxidation treatment, or a ceramic film made of yttrium oxide.

An insulating member 28 is provided on the tubular member 26 . The insulating member 28 has an insulating property and is made of ceramic such as quartz. The insulating member 28 has a substantially cylindrical shape and extends along the outer peripheries of the electrode plate 21 , the lower electrode 18 , and the electrostatic chuck 20 . The edge portion of the baffle plate 14 b may be provided between the tubular member 26 and the insulating member 28 and may be embedded between the tubular member 26 and the insulating member 28 .

The supporting part 15 , the supporting table 16 , the tubular member 26 , and the insulating member 28 constitute a support assembly SA. The support assembly SA extends from the first space S 1 to the second space S 2 .

The plasma processing apparatus 10 further includes an upper electrode 30 . The upper electrode 30 is provided above the supporting table 16 . The upper electrode 30 blocks an upper opening of the chamber body 12 in cooperation with a member 32 . The member 32 has an insulating property. The upper electrode 30 is held on an upper portion of the chamber body 12 through the member 32 .

The upper electrode 30 includes a ceiling plate 34 and a holder 36 . A bottom surface of the ceiling plate 34 defines the inner space S (or the first space S 1 ). The ceiling plate 34 is provided with a plurality of gas injection holes 34 a . The gas injection holes 34 a penetrate through the ceiling plate 34 in a plate thickness direction (vertical direction). The ceiling plate 34 is made of, e.g., silicon, but is not limited thereto. Alternatively, the ceiling plate 34 may have a structure in which a plasma resistant film is formed on a surface of an aluminum base material. This film may be a film formed by anodic oxidation treatment or a ceramic film made of yttrium oxide.

The holder 36 detachably holds the ceiling plate 34 . The holder 36 may be made of a conductive material, e.g., aluminum. A heater HT 36 may be provided in the upper electrode 30 , e.g., in the holder 36 . The heater HT 36 generates heat when power is supplied from a heater controller HC 36 to the heater HT 36 . A high frequency filter FT 36 may be provided between the heater HT 36 and the heater controller HC 36 to prevent a high frequency from flowing into the heater controller HC 36 .

A gas diffusion space 36 a is formed inside the holder 36 . A plurality of gas holes 36 b extends downward from the gas diffusion space 36 a . The gas holes 36 b communicate with the respective gas injection holes 34 a . A gas inlet port 36 c for introducing a gas into the gas diffusion space 36 a is formed in the holder 36 . A gas supply line 38 is connected to the gas inlet port 36 c.

A gas supply unit 40 is connected to the gas supply line 38 . The gas supply unit 40 and a gas supply unit 42 to be described later constitute a gas supply system. The gas supply system is connected to the first space S 1 . The gas supply unit 40 includes a gas source group 40 s , a valve group 40 a , a flow rate controller group 40 b , and a valve group 40 c . The gas source group 40 s includes a plurality of gas sources. The gas sources include a plurality of gas sources used in the method MT. The gas sources of the gas source group 40 s include a source of one of a first gas and a second gas for forming a film to be described later. Each of the valve group 40 a and the valve group 40 c includes a plurality of valves. The flow rate controller group 40 b includes a plurality of flow rate controllers. Each of the flow rate controllers of the flow rate controller group 40 b is a mass flow controller or a pressure control type flow controller. The gas sources of the gas source group 40 s are respectively connected to the gas supply line 38 through corresponding valves of the valve group 40 a , corresponding flow controllers of the flow rate control group 40 b , and corresponding valves of the valve group 40 c . The gas from the gas supply unit 40 is supplied into the first space S 1 via the gas supply line 38 , the gas diffusion space 36 a , the gas holes 36 b , and the gas injection holes 34 a.

The plasma processing apparatus 10 further includes a gas supply unit 42 . The gas supply unit 42 includes a gas source 42 s , a valve 42 a , a flow rate controller 42 b , and a valve 42 c . The gas source 42 s is the source of the other one of the first gas and the second gas. The flow rate controller 42 b is a mass flow controller or a pressure control type flow controller. The gas source 42 s is connected to the first space S 1 via the valve 42 a , the flow rate controller 42 b , and the valve 42 c . The gas from the gas supply unit 42 is supplied into the first space S 1 .

A gas exhaust line 50 is connected to the bottom portion of the chamber body 12 of the plasma processing apparatus 10 . A gas exhaust unit 52 is connected to the gas exhaust line 50 . The gas exhaust unit 52 is connected to the second space S 2 via the gas exhaust line 50 . The gas exhaust unit 52 is also connected to the first space S 1 via the second space S 2 and the through-holes of the partition wall 14 . The gas exhaust unit 52 includes a pressure control valve and a depressurization pump. The depressurization pump is connected to the second space S 2 via a pressure control valve. The depressurization pump may be a turbo molecular pump and/or a dry pump.

The plasma processing apparatus 10 can generate plasma of the gas supplied into the first space S 1 in the first space S 1 . The plasma processing apparatus 10 further includes a first high frequency power supply 61 . The first high frequency power supply 61 generates a first high frequency power for plasma generation. The first high frequency power has a frequency within a range of 27 MHz to 100 MHz, for example. The first high frequency power supply 61 is connected to the upper electrode 30 via a matching unit 63 . The matching unit 63 has a matching circuit for matching an output impedance of the first high frequency power supply 61 and an impedance of a load side (the upper electrode 30 side). The first high frequency power supply 61 may be connected to the lower electrode 18 via the matching unit 63 . In that case, the upper electrode 30 is electrically grounded.

The plasma processing apparatus 10 may further include a second high frequency power supply 62 . The second high frequency power supply 62 generates a second high frequency power (for bias) for attracting ions to the substrate W. The frequency of the second high frequency is lower than the frequency of the first high frequency. The frequency of the second high frequency is within a range of 400 kHz to 13.56 MHz, for example. The second high frequency power supply 62 is connected to the lower electrode 18 via a matching unit 64 . The matching unit 64 has a matching circuit for matching an output impedance of the second high frequency power supply 62 and an impedance of a load side (the lower electrode 18 side).

In the plasma processing apparatus 10 , when the first high frequency power is supplied in a state in which a gas is supplied into the first space S 1 , the gas is excited and plasma is generated in the first space S 1 . When the second high frequency power is supplied to the lower electrode 18 , ions in the plasma are accelerated toward the substrate W.

The plasma processing apparatus 10 further includes a DC power supply 70 . The DC power supply 70 is connected to the upper electrode 30 . The DC power supply 70 is configured to apply a negative DC voltage to the upper electrode 30 . When the negative DC voltage is applied to the upper electrode 30 , positive ions in the plasma generated in the first space S 1 collide with the ceiling plate 34 of the upper electrode 30 . When the positive ions collide with the ceiling plate 34 , secondary electrons are emitted from the ceiling plate 34 . In the case where the ceiling plate 34 is made of silicon, when the positive ions collide with the ceiling plate 34 , silicon can be released from the ceiling plate 34 .

In the plasma processing apparatus 10 , the surface that defines the inner space S includes a first surface F 1 and a second surface F 2 . The first surface F 1 defines the first space S 1 and includes a part 14 e of the surface of the partition wall 14 and a part SAe of the surface of the support assembly SA. In the example shown in FIG. 2 , the part SAe of the surface of the support assembly SA is defined by the insulating member 28 . The first surface F 1 also includes a part 32 e of the surface of the member 32 and a part 30 e of the surface of the upper electrode 30 . In the example shown in FIG. 2 , the part 30 e of the surface of the upper electrode 30 is the bottom surface of the ceiling plate 34 .

The second surface F 2 defines the second space S 2 and includes a part 12 f of the surface of the chamber body 12 and another part 14 f of the surface of the partition wall 14 . In the example shown in FIG. 2 , the part 12 f of the surface of the chamber body 12 is defined by the sidewall and the bottom portion of the chamber body 12 . The second surface F 2 also includes a part SAf of the surface of the support assembly SA. In the example shown in FIG. 2 , the part SAf of the surface of the support assembly SA is defined by the tubular member 26 .

The plasma processing apparatus 10 may further include a heater HT 72 . The heater HT 72 is provided outside the chamber 11 . Power is supplied from a heater controller HC 72 to the heater HT 72 . The heater HT 72 generates heat when the power is supplied from the heater controller HC 72 to the heater HT 72 . The plasma processing apparatus 10 may further include a heater HT 74 . The heater HT 74 is a non-contact heater that heats the components of the plasma processing apparatus 10 in a non-contact manner. The heater HT 74 is, e.g., a lamp heater. The heater HT 74 is provided in the inner space S, e.g., in the second space S 2 . When the power is supplied from the heater controller HC 74 to the heater HT 74 , the heater HT 74 generates heat and heats the components of the plasma processing apparatus 10 in a non-contact manner.

In one embodiment, the plasma processing apparatus 10 may further include a control unit 80 . The control unit 80 is configured to control the respective components of the plasma processing apparatus 10 . The control unit 80 may be a computer including a processor, a storage device such as and a memory, an input device, a display device, and the like. The control unit 80 executes a control program stored in the storage device and controls the respective components of the plasma processing apparatus 10 based on a recipe data stored in the storage device. Accordingly, the plasma processing apparatus 10 executes a process specified by the recipe data. For example, the control unit 80 controls the respective components of the plasma processing apparatus 10 in executing the method MT.

The method MT will be described with reference to FIG. 1 . Hereinafter, the case in which the method MT is applied to the plasma processing apparatus 10 will be described as an example. The method MT includes steps ST 1 and ST 2 . In the step ST 1 , a film is formed on the surfaces of the components of the plasma processing apparatus 10 . The step ST 1 is executed before substrate treatment in a step SP. The step ST 2 is executed after the substrate treatment in the step SP. In the step ST 2 , a deposit generated during the substrate treatment is removed together with the film. The method MT may further include at least one of steps STa, STb and STc. In the following description, the case in which the method MT includes the steps ST 1 , SP and ST 2 ; the film on the first surface F 1 is not removed in the step Sta; and the step STc is not executed will be described. In the following description, FIGS. 1 and 3 to 5 will be referred to. FIGS. 3 to 5 show states of the plasma processing apparatus after the execution of the steps ST 1 , SP and ST 2 .

The method MT starts from the step ST 1 . In the step ST 1 , as shown in FIG. 3 , a film CF is formed on the surfaces of the components of the plasma processing apparatus 10 , i.e., on the surfaces that define the inner space S. The surfaces that define the inner space S include the first surface F 1 and the second surface F 2 . The components include the chamber 11 . The chamber 11 includes the chamber body 12 , the upper electrode 30 (e.g., the ceiling plate 34 ), and the member 32 . The components further include components provided in the chamber 11 . The components provided in the chamber 11 include the partition wall 14 , the electrostatic chuck 20 , the tubular member 26 , the insulating member 28 , and the focus ring FR.

The film CF may be formed in a state where a protection member (e.g., dummy substrate DW) is mounted on the supporting table 16 (the electrostatic chuck 20 ). Alternatively, the film CF may be formed in a state where no object is mounted on the supporting table 16 (the electrostatic chuck 20 ). In order to form the coating CF, a first gas containing a first compound (i.e., vapor) is supplied from the gas supply unit 40 into the inner space S and a second compound (e.g., vapor) is supplied into the inner space S. The first gas may be supplied from the gas supply unit 42 and the second gas may be supplied from the gas supply unit 40 .

The first compound, which is a raw material monomer, is isocyanate. The second compound, which is a raw material monomer, is amine or a compound having a hydroxyl group. In the step ST 1 , polymerization of the first compound and the second compound occurs in the inner space S. Due to the polymerization of the first compound and the second compound, a compound forming the film CF is generated. When the second compound is amine, the compound forming the film CF may be oligomer or polymer having a urea bond. When the second compound is a compound having a hydroxyl group, the compound forming the film CF may be oligomer or polymer having a urethane bond. The polymerization of the first compound and the second compound occurs at a temperature lower than the temperature at which depolymerization of the compound forming the film CF occurs. The polymerization of the first compound and the second compound occurs within a temperature range of 0° C. to 150° C., for example. In the step ST 1 , the heating may be performed by the heater, if necessary, in order to set the temperature in the inner space S to the above temperature. One or more heaters among the heaters HT 12 , HT 14 , HT 20 , HT 36 , HT 72 and HT 74 are used for the heating in the step ST 1 .

Hereinafter, examples of the first compound, the second compound, and the compound forming the film CF will be described. As for the first compound, monofunctional isocyanate shown in the following formula (1) or bifunctional isocyanate shown in the following formula (2) may be used. In the formulas (1) and (2), R represents a saturated hydrocarbon group such as an alkyl group (linear alkyl group or cyclic alkyl group), an unsaturated hydrocarbon group such as an aryl group or the like, or a group containing a hetero atom such as N, O, S, F, Si or the like. The group containing a hetero atom includes a saturated hydrocarbon group or an unsaturated hydrocarbon group whose elements are partially substituted with N, O, S, F, Si, or the like. Hydrogen in C—H bond contained in the atomic group represented by R in the formulas (1) and (2) may be substituted with another substituent. As for the isocyanate that is the first compound, an aliphatic compound or an aromatic compound may be used, for example. As for the aliphatic compound, an aliphatic chain compound or an aliphatic cyclic compound may be used. The aliphatic compound may include, e.g., hexamethylene diisocyanate. The aliphatic cyclic compound may include, e.g., 1,3-bis (isocyanatomethyl) cyclohexane (H6XDI).

[Formula 1]

OCN—R  (1)

[Formula 2]

OCN—R—NCO  (2)

As for the second compound, monofunctional amine shown in the following formula (3) or bifunctional amines shown in the following formula (4) may be used. In the formulas (3) and (4), R represents a saturated hydrocarbon group such as an alkyl group (linear alkyl group or a cyclic alkyl group) or the like, an unsaturated hydrocarbon group such as an aryl group or the like, or a group containing a hetero atom such as N, O, S, F, Si or the like. The group containing a hetero atom includes a saturated hydrocarbon group or an unsaturated hydrocarbon group whose elements are partially substituted with N, O, S, F, Si, or the like. Hydrogen in C—H bond contained in the atomic group represented by R in the formulas (3) and (4) may be substituted with another substituent. The atomic group of the first compound polymerized in the step ST 1 , which is the atomic group represented by R in the formula (1) or (2), may be the same as or different from the atomic group of the second compound polymerized in the step ST 1 , which is the atomic group represented by R in the formula (3) or (4). As for the amine that is the second compound, an aliphatic compound or an aromatic compound may be used, for example. As for the aliphatic compound, an aliphatic chain compound or an aliphatic cyclic compound may be used. The aliphatic compound may include, e.g., 1,12-diaminododecane (DAD). The aliphatic cyclic compound may include 1,3-bis (aminomethyl) cyclohexane (H6XDA). The amine that is the second compound may be secondary amine.

[Formula 3]

H 2 N—R  (3)

[Formula 4]

H 2 N—R—NH 2   (4)

As for the second compound, a monofunctional compound having a hydroxyl group shown in the following formula (5) or a bifunctional compound having a hydroxyl group shown in the formula (6) may be used. In the formulas (5) and (6), R represents a saturated hydrocarbon group such as an alkyl group (linear alkyl group or cyclic alkyl group) or the like, an unsaturated hydrocarbon group such as an aryl group or the like, or a group containing a hetero atom such as N, O, S, F, Si or the like. The group containing a hetero atom includes a saturated hydrocarbon group or an unsaturated hydrocarbon group whose elements are partially substituted with N, O, S, F, Si, or the like. Hydrogen in C—H bond contained in the atomic group represented by R in the formulas (5) and (6) may be substituted with another substituent. The atomic group of the first compound polymerized in the step ST 1 , which is the atomic group represented by R in the formula (1) or (2), may be the same as or different from the atomic group of the second compound polymerized in the step ST 1 , which is the atomic group represented by R in the formula (5) or (6). The compound having a hydroxyl group is alcohol or phenol. As for the alcohol that is the second compound, diethylene glycol, and 1,2-cyclohexane diol may be used, for example. As for the phenol that is the second compound, hydroquinone, and 1,2,4-trihydroxybenzene may be used, for example.

[Formula 5]

HO—R  (5)

[Formula 6]

HO—R—OH  (6)

As for the compound forming the film CF, compounds having a urea bond shown in the following formulas (7) to (10) may be used. The compound shown in the formula (7) is generated by polymerization of the compound shown in the formula (1) and the compound shown in the formula (3). The compound shown in the formula (8) is generated by polymerization of the compound shown in the formula (1) and the compound shown in the formula (4). Alternatively, the compound shown in the formula (8) is generated by polymerization of the compound shown in the formula (2) and the compound shown in the formula (3). The compound shown in the formula (9) is generated by polymerization of the compound shown in the formula (2) and the compound shown in the formula (4). The compound shown in the formula (10) has a structure in which both ends of the polymer shown in the formula (9) are terminated with a monomer having an isocyanate group (e.g., the compound shown in the formula (1)) and a monomer having an amino group (e.g., the compound shown in the formula (3)). In the formulas (9) and (10), n is an integer of 2 or more.

As for another compound forming the film CF, compounds having a urethane bond shown in the following formulas (11) to (15) may be used. The compound shown in the formula (11) is generated by polymerization of the compound shown in the formula (1) and the compound shown in the formula (5). The compound shown in the formula (12) is generated by polymerization of the compound shown in the formula (1) and the compound shown in the formula (6). The compound shown in the formula (13) is generated by polymerization of the compound shown in the formula (2) and the compound shown in the formula (5). The compound shown in the formula (14) is generated by polymerization of the compound shown in the formula (2) and the compound shown in the formula (6). The compound shown in the formula (15) has a structure in which both ends of the polymer shown in the formula (14) are terminated with a monomer having an isocyanate group (e.g., the compound shown in the formula (1)) and a monomer having a hydroxyl group (e.g., the compound shown in the formula (5)). In the formulas (14) and (15), n is an integer of 2 or more.

The following formulas (16) to (26) show examples of the structure of the atomic group represented by R in the formulas (2), (4) and (6). In the formulas (16) to (26), R 1 represents an isocyanate group, an amino group, or a hydroxyl group. As shown in the formulas (16) to (22), each of the first compound and the second compound may have a benzene ring as the atomic group represented by R1. Each of the compounds shown in formulas (16) to (19) does not have carbon between the benzene ring and the isocyanate group, the amino group, or the hydroxyl group. Each of the compounds shown in formulas (20) to (22) has carbon between the benzene ring and the isocyanate group, the amino group, or the hydroxyl group. As shown in the formulas (23) and (24), each of the first compound and the second compound may have alicyclic hydrocarbon as the atomic group represented by R. As shown in the formulas (25) and (26), in each of the first compound and the second compound, the atomic group represented by R may be an aliphatic group.

When the step ST 1 is executed in a state where the protection member is mounted on the supporting table 16 (the electrostatic chuck 20 ), the protection member may be removed from the supporting table 16 before the processing proceeds to a next step. When the step ST 1 is executed in a state where no object is mounted on the supporting table 16 (the electrostatic chuck 20 ), the film CF extending on the surface of the electrostatic chuck 20 may be removed in the subsequent step STa. For example, in the step STa, the heater HT 20 may generate heat so that depolymerization of the compound forming the film CF extending on the surface of the electrostatic chuck 20 occurs. The temperature at which the depolymerization of the compound forming the film CF occurs is within a range of 200° C. to 350° C., for example. By circulating the coolant between the flow path 18 f and the chiller unit, it is possible to prevent the film CF from being removed from the surfaces of the components other than the electrostatic chuck 20 .

Next, the step STb may be executed. The step STb will be described later. Next, the step SP is executed. In the step SP, the substrate treatment is performed in the inner space S in a state where the substrate W is mounted on the supporting table 16 (the electrostatic chuck 20 ). The substrate treatment in the step SP includes at least one of film formation and etching. The substrate treatment in the step SP may include film formation and etching performed after the film formation. The film formation may be performed by a chemical vapor deposition method (CVD method), a plasma enhanced CVD (PECVD) method, an atomic layer deposition method (ALD method), or a plasma enhanced ALD Method (PEALD method). The etching included in the substrate treatment in the step SP includes plasma etching. The film in the substrate W which is etched by the plasma etching may be any film. The film in the substrate W which is etched by the plasma etching may be a silicon-containing film or a metal-containing film.

The substrate treatment in the step SP is performed at a temperature at which depolymerization of the compound forming the film CF does not occur. The compound forming the film CF is depolymerized by heating the film CF. The depolymerization is reverse reaction of the polymerization. During the depolymerization, the compound forming the forming the film CF is decomposed into the first compound and the second compound. The temperature at which the depolymerization of the compound forming the film CF occurs is within a range of 200° C. to 350° C., for example.

When the substrate treatment in the step SP is executed, a deposit DS is formed on the film CF as shown in FIG. 4 . The deposit DS is a film formed by the film formation and/or an etching by-product.

Next, the step ST 2 is executed. In the step ST 2 , the deposit DS formed on the film CF is removed together with the film CF. In the step ST 2 , the components of the plasma processing apparatus 10 are heated by the heater so that the depolymerization of the compound forming the film CF occurs. As described above, the depolymerization of the compound forming the film CF occurs at a temperature of 200° C. to 350° C., for example. One or more heaters among the heaters HT 12 , HT 14 , HT 20 , HT 36 , HT 72 and HT 74 are used in the step ST 2 . In the step ST 2 , the deposit DS is removed, together with the compound generated by the depolymerization of the film CF, from the surface of the component of the plasma processing apparatus 10 . In other words, in the step ST 2 , the deposit DS is removed, together with the compound generated by the depolymerization of the film CF, from the surface that defines the inner space S.

Hereinafter, the case in which the method MT includes the steps ST 1 , STa, STb, SP, STc and ST 2 and the film on the first surface F 1 is removed in the step STa will be described. In that case, in the substrate treatment in the step SP of the method MT, a deposit DS that can be removed from the first surface F 1 by the plasma treatment in the step STc is generated. In the following description, the substrate treatment in the step SP includes film formation. In the following description, FIGS. 1, 3, 5 and 6 to 9 will be referred to. FIGS. 6 to 9 show the states of the plasma processing apparatus after the execution of the steps STa, STb, SP and STc.

As described above, in the step ST 1 , the film CF is formed on the surfaces of the components of the plasma processing apparatus 10 , i.e., the surface (the first surface F 1 and the second surface F 2 ) that defines the inner space S, as shown in FIG. 3 .

Next, the step STa is executed. In the step STa, the film CF extending on the first surface F 1 is removed by plasma treatment. In the step STa, plasma of a third gas is generated in the first space S 1 . The third gas can etch the film CF by active species from the plasma of the third gas. The third gas used in the step STa may contain an oxygen-containing gas such as oxygen gas, carbon monoxide gas, and carbon dioxide gas. Alternatively, the third gas may be a mixed gas containing hydrogen gas and nitrogen gas. In the step STa, the third gas is supplied from the gas supply unit 40 into the first space S 1 and the first high frequency power is supplied to the upper electrode 30 . In addition, the gas exhaust unit 52 is controlled to set a pressure in the first space S 1 to a specified pressure. In the step STa, the film CF extending on the first surface F 1 is etched by the active species from the plasma of the third gas. As a result, as shown in FIG. 6 , the film CF on the first surface F 1 is removed. The step STa may be executed in a state where no object is mounted on the supporting table 16 (the electrostatic chuck 20 ). Alternatively, the step STa may be executed in a state where the protection member (e.g., dummy substrate DW) is mounted on the supporting table 16 (the electrostatic chuck 20 ).

Next, the step STb is executed. In the step STb, the same treatment as the substrate treatment in the step SP is performed. In the step STb, only the same treatment as the film formation included in the substrate treatment in the step SP may be performed. The step STb is executed in a state where the protection member (e.g., dummy substrate DW) is mounted on the supporting table 16 (the electrostatic chuck 20 ). The step STb may be executed multiple times. With respect to the treatment in the step STb, the substrate treatment (or film formation) in the SP is referred to. When the step STb is executed, a deposit DS is formed on the first surface F 1 and also formed on the second surface F 2 via the film CF, as shown in FIG. 7 . The deposit DS is a film formed by the film formation and/or an etching by-product.

Next, the step SP is executed. In the step SP, the substrate treatment is performed in a state where the substrate W is mounted on the supporting table 16 (the electrostatic chuck 20 ). In this example, the substrate treatment includes film formation. The film formation may be performed by a CVD method, a PECVD method, an ALD method, or an ALD PEALD method. The substrate treatment performed in the step SP may include plasma etching as well as the film formation.

The substrate treatment in the step SP is performed at a temperature at which the depolymerization of the compound forming the film CF does not occur. As described above, the depolymerization of the compound forming the film CF occurs at a temperature within a range of from 200° C. to 350° C., for example.

When the step SP is executed, a deposit DS is formed on the first surface F 1 and also formed on the second surface F 2 via the film CF, as shown in FIG. 8 . The deposit DS may be made of any material. The deposit DS is made of, e.g., silicon oxide or tungsten. The step SP may be sequentially executed for a plurality of substrates W. After the execution of the step SP, the substrate W is unloaded from the inner space S.

Next, the step STc of the method MT is executed. In the step STc, the deposit DS on the first surface F 1 is removed. In the step STc, plasma of a fourth gas is generated in the first space S 1 . The fourth gas may be any gas that can etch the deposit DS by active species from the plasma of the fourth gas. When the deposit DS is made of silicon oxide or tungsten, the fourth gas contains, e.g., a fluorocarbon gas. In the step STc, the fourth gas is supplied from the gas supply unit 40 into the first space S 1 and the first high frequency power is supplied to the upper electrode 30 . Further, the gas exhaust unit 52 is controlled to set a pressure in the first space S 1 to a specified pressure. In the step STc, the deposit DS formed on the first surface F 1 is etched by the active species from the plasma of the fourth gas. As a result, as shown in FIG. 9 , the deposit DS on the first surface F 1 is removed. The step STc may be executed in a state where no object is mounted on the supporting table 16 (the electrostatic chuck 20 ). Alternatively, the step STc may be executed in a state where the protection member (e.g., dummy substrate DW) is mounted on the supporting table 16 (the electrostatic chuck 20 ).

Next, the step ST 2 is executed. In the step ST 2 , as described above, the deposit DS formed on the film CF is removed together with the film CF (see FIG. 5 ). In this example, the deposit DS is removed together with the film CF from the surface of the component of the plasma processing apparatus 10 which is included in the second surface F 2 . In the step ST 2 , the components of the plasma processing apparatus 10 are heated by the heater so that the depolymerization of the compound forming the film CF occurs. As described above, the depolymerization of the compound forming the film CF occurs at a temperature of 200° C. to 350° C., for example. One or more heaters among the heaters HT 12 , HT 14 , HT 20 , HT 36 , HT 72 and HT 74 are used in the step ST 2 .

In the method MT, the film CF is formed on the surfaces of the components of the plasma processing apparatus 10 before the substrate treatment is executed. The compound forming the film CF is generated by polymerization of isocyanate and amine or by polymerization of isocyanate and a compound having a hydroxyl group. In the method MT, the components are heated so that depolymerization of the compound forming the film CF occurs, to thereby remove the deposit DS formed on the surfaces of the components via the film CF by the substrate treatment. Accordingly, the deposit DS formed on the film CF by the substrate treatment is removed together with the film CF. Therefore, in accordance with the method MT, it is possible to remove the deposit DS by a process different from the plasma cleaning.

In the step STa of method MT according to one embodiment, the film CF extending on the first surface F 1 is removed as described above. Even when the deposit DS formed on the first surface F 1 that defines the first space S 1 can be removed by the plasma cleaning, it is difficult to remove the deposit DS formed on the second surface F 2 that defines a space where the active species from the plasma hardly reaches, i.e., the second space S 2 , by the plasma cleaning. In accordance with the present embodiment, the film CF on the second surface F 2 remains and, thus, the deposit DS formed on the second surface F 2 via the film CF can be removed without using the plasma cleaning.

The deposit DS that cannot be removed by the plasma cleaning can be removed by wet cleaning using chemicals. In the wet cleaning, the component of the plasma processing apparatus on which the deposit DS to be removed is formed is damaged and, thus, the exchange frequency of the component is increased. On the other hand, in the method MT, the deposit DS can be removed by heating. Therefore, the damage inflicted to the component of the plasma processing apparatus is suppressed, and the exchange frequency of the component is decreased.

In one embodiment, as described above, the step STb is executed before the substrate treatment in the step SP is executed. In the step STb, the deposit DS is formed by the same treatment as the substrate treatment in the step SP, and the inner space S is surrounded by the deposit DS. Therefore, during the execution of the step SP, the change in the material of the surface surrounding the inner space S is suppressed. As a result, even if the substrate treatment in the step SP is sequentially executed for a plurality of substrates W, the variation in the substrate treatment for a plurality of substrates W is suppressed.

Hereinafter, an example of the substrate treatment executed in the step SP will be described. FIG. 10 is a flowchart showing an example of the substrate treatment in the step SP in the cleaning method shown in FIG. 1 . The substrate treatment in the step SP shown in FIG. 10 includes steps ST 41 to ST 46 and a step STR. In the step STR, a width of an opening of a mask is adjusted. The step STR is executed to adjust the width of the opening of the mask for plasma etching in at least one of the steps ST 42 , ST 43 , ST 44 and ST 46 .

FIG. 11 is a partially enlarged cross sectional view of an example of a substrate to which the example of the substrate treatment in the step SP shown in FIG. 10 can be applied. The substrate W shown in FIG. 11 may have a substantially disc shape. In one embodiment, the substrate W includes a silicon-containing film SF, an organic film OF, an anti-reflection film BF, and a resist mask RM. The silicon-containing film SF is provided on a base layer BL. In one embodiment, the silicon-containing film SF includes a first film SFa and a second film SFb. The first film SFa is provided on the base layer BL, and the second film SFb is provided on the first film SFa. The first film SFa and the second film SFb contain silicon and are made of different materials. The first film SFa is made of, e.g., silicon. The first film SFa may be a polycrystalline silicon film or an amorphous silicon film. The second film SFb is made of, e.g., silicon oxide.

The organic film OF is provided on the silicon-containing film SF. The anti-reflection film BF is provided on the organic film OF. The anti-reflection film BF contains silicon. The resist mask RM is provided on the anti-reflection film BF. The resist mask RM has a pattern to be transferred to the anti-reflection film BF by plasma etching. In other words, the resist mask RM provides an opening ORM. The opening ORM is a groove or a hole, and partially exposes the surface of the anti-reflection film BF. The resist mask RM can be formed by patterning the resist film by a photolithography technique.

Hereinafter, FIGS. 10 and 12A to 12E will be referred to. FIGS. 12A to 12D are partially enlarged cross sectional views of the substrate obtained during the execution of the example of the substrate treatment in the step SP. FIG. 12E is a partially enlarged cross sectional view of the substrate after the execution of the example of the substrate treatment in the step SP.

As shown in FIG. 10 , in one example of the substrate treatment in the step SP, the step ST 41 is executed. In the step ST 41 , the resist mask RM is modified. Specifically, in the step ST 41 , a processing gas is supplied into the first space S 1 in a state where the substrate W shown in FIG. 11 is mounted on the supporting table 16 (the electrostatic chuck 20 ). The processing gas used in the step ST 41 may be, e.g., a mixed gas of hydrogen gas and rare gas. In the step ST 41 , the gas exhaust unit 52 is controlled to set a pressure in the first space S 1 to a specified pressure. In the step ST 41 , the first high frequency power from the first high frequency power supply 61 is supplied to the upper electrode 30 . In the step ST 41 , a voltage from the DC power supply 70 is applied to the upper electrode 30 . In the step ST 41 , the second high frequency power from the second high frequency power supply 62 may be supplied to the lower electrode 18 or may not be supplied. By executing the step ST 41 , plasma of the processing gas is generated in the first space S 1 . Positive ions in the plasma collide with the ceiling plate 34 of the upper electrode 30 . As a result, secondary electrons are emitted from the ceiling plate 34 . The resist mask RM is modified by the emitted secondary electrons.

In an example of the substrate treatment in the step SP, the step ST 42 is executed after the step ST 41 . In the step ST 42 , plasma etching is performed to transfer the pattern of the mask MK 1 to the anti-reflection film BF. The mask MK 1 is the resist mask RM or a mask obtained by adjusting the width of the opening of the resist mask RM in the step STR.

In the step ST 42 , the processing gas is supplied into the first space S 1 in a state where the substrate W having the mask MK 1 is mounted on the supporting table 16 (the electrostatic chuck 20 ). The processing gas used in the step ST 42 may contain, e.g., a fluorocarbon gas. In the step ST 42 , the gas exhaust unit 52 is controlled to set a pressure in the first space S 1 to a specified pressure. In the step ST 42 , the first high frequency power from the first high frequency power supply 61 is supplied to the upper electrode 30 . In the step ST 42 , the second high frequency power from the second high frequency power supply 62 is supplied to the lower electrode 18 . By executing the step ST 42 , plasma of the processing gas is generated in the first space S 1 . Then, the anti-reflection film BF is etched by active species such as ions and/or radicals in the plasma. As a result, as shown in FIG. 12A , the pattern of the mask MK 1 is transferred to the anti-reflection film BF. After the step ST 42 is executed, the mask MK 1 may be removed.

In an example of the substrate treatment in the step SP, the step ST 43 is executed after the step ST 42 . In the step ST 43 , plasma etching is performed to transfer the pattern of the mask MK 2 to the organic film OF. The mask MK 2 is a mask obtained from the anti-reflection film BF by the plasma etching in the step ST 42 or a mask obtained by adjusting the width of the mask obtained from the anti-reflection film BF in the step STR.

In the step ST 43 , the processing gas is supplied into the first space S 1 in a state where the substrate W having the mask MK 2 is mounted on the supporting table 16 (the electrostatic chuck 20 ). The processing gas used in the step ST 43 contains an oxygen-containing gas (e.g., oxygen gas). Alternatively, the processing gas used in the step ST 43 includes hydrogen gas and nitrogen gas. In the step ST 43 , the gas exhaust unit 52 is controlled to set a pressure in the first space S 1 to a specified pressure. In the step ST 43 , the first high frequency power from the first high frequency power supply 61 is supplied to the upper electrode 30 . In the step ST 43 , the second high frequency power from the second high frequency power supply 62 is supplied to the lower electrode 18 . By executing the step ST 43 , plasma of the processing gas is generated in the first space S 1 . Then, the organic film OF is etched by active species such as ions and/or radicals in the plasma. As a result, as shown in FIG. 12B , the pattern of the mask MK 2 is transferred to the organic film OF, and an organic mask OFM is obtained from the organic film OF. After the step ST 43 is executed, the mask MK 2 may be removed.

In an example of the substrate treatment in the step SP, the step ST 44 is executed after step ST 43 . In the step ST 44 , plasma etching is performed to transfer a pattern of a mask MK 3 to the second film SFb. The mask MK 3 is the organic mask OFM or a mask obtained by adjusting the width of the opening of the organic mask OFM in the step STR.

In the step ST 44 , the processing gas is supplied into the first space S 1 in a state where the substrate W having the mask MK 3 is mounted on the supporting table 16 (the electrostatic chuck 20 ). The processing gas used in the step ST 44 may contain a fluorocarbon gas. In the step ST 44 , the gas exhaust unit 52 is controlled to set a pressure in the first space S 1 to a specified pressure. In the step ST 44 , the first high frequency power from the first high frequency power supply 61 is supplied to the upper electrode 30 . In the step ST 44 , the second high frequency power from the second high frequency power supply 62 is supplied to the lower electrode 18 . By executing the step ST 44 , plasma of the processing gas is generated in the first space S 1 . Then, the second film SFb is etched by active species such as ions and/or radicals in the plasma. As a result, as shown in FIG. 12C , the pattern of the mask MK 3 is transferred to the second film SFb.

In an example of the substrate treatment in the step SP, the step ST 45 is then executed. In the step ST 45 , the mask MK 3 is removed. In the step ST 45 , the processing gas is supplied to the first space S 1 in a state where the substrate W shown in FIG. 12C is mounted on the supporting table 16 (the electrostatic chuck 20 ). The processing gas used in the step ST 45 contains an oxygen-containing gas (e.g., oxygen gas). Alternatively, the processing gas used in the step ST 45 contains hydrogen gas and nitrogen gas. In the step ST 45 , the gas exhaust unit 52 is controlled to set a pressure in the first space S 1 to a specified pressure. In the step ST 45 , the first high frequency power from the first high frequency power supply 61 is supplied to the upper electrode 30 . In the step ST 45 , the second high frequency power from the second high frequency power supply 62 may be supplied to the lower electrode 18 , or may not be supplied. By executing the step ST 45 , plasma of the processing gas is generated in the first space S 1 . Then, the mask MK 3 , i.e., the organic mask OFM itself or the mask including the organic mask OFM, is removed by active species such as ions and/or radicals in the plasma. As a result, the substrate W shown in FIG. 12D is obtained.

In an example of the substrate treatment in the step SP, the step ST 46 is executed after the step ST 45 . In the step ST 46 , plasma etching is performed to transfer a pattern of a mask MK 4 to the first film SFa. The mask MK 4 is a mask obtained from the second film SFb by the plasma etching in the step ST 44 , or a mask obtained by adjusting the width of the mask obtained from the second film SFb in the step STR.

In the step ST 46 , the processing gas is supplied into the first space S 1 in a state where the substrate W having the mask MK 4 is mounted on the supporting table 16 (the electrostatic chuck 20 ). The processing gas used in the step ST 46 may include halogen-based gas. The processing gas used in the step ST 46 may include, e.g., at least one of chlorine gas and hydrogen bromide gas. In the step ST 46 , the gas exhaust unit 52 is controlled to set a pressure in the first space S 1 to a specified pressure. In the step ST 46 , the first high frequency power from the first high frequency power supply 61 is supplied to the upper electrode 30 . In the step ST 46 , the second high frequency power from the second high frequency power supply 62 is supplied to the lower electrode 18 . By executing the step ST 46 , plasma of the processing gas is generated in the first space S 1 . Then, the first film SFa is etched by active species such as ions and/or radicals in the plasma. Accordingly, as shown in FIG. 12E , the pattern of the mask MK 4 is transferred to the first film SFa. The plasma etching may be performed to remove the oxide film formed on the surface of the first film SFa before the execution of the step ST 46 . A fluorocarbon gas may be used for the plasma etching for removing the oxide film.

Hereinafter, the step STR will be described with reference to FIGS. 13, 14A and 14B . FIG. 13 is a flowchart showing an example of the step STR shown in FIG. 10 . FIG. 14A is a partially enlarged cross sectional view of the substrate after the film formation in the step STR. FIG. 14B is a partially enlarged cross sectional view of the substrate after the etching of the film in the step STR.

The step STR includes film formation DP. The film formation DP is an example of the film formation included in the substrate treatment in the step SP, and is performed by the PEALD method. By performing the film formation DP, as shown in FIG. 14A , the film DF is formed on the surface of the substrate W, i.e., on the surface of the mask MK and the surface of an underlying film UF. The mask MK is a resist mask RM, a mask formed from the anti-reflection film BF by executing the step ST 42 , an organic mask OFM, or a mask formed from the second film SFb by executing the step ST 44 . When the mask MK is the resist mask RM, the anti-reflection film BF serves as the underlying film UF. When the mask MK is a mask formed from the anti-reflection film BF by executing the step ST 42 , the organic film OF serves as the underlying film UF. When the mask MK is the organic mask OFM, the second film SFb serves as the underlying film UF. When the mask MK is a mask formed from the second film SFb by executing the step ST 44 , the first film Sfa serves as the underlying film UF.

In the film formation DP, a cycle CY is executed at least once to form the film DF. The cycle CY includes the steps ST 11 to ST 16 . In the step ST 11 , a precursor gas is supplied from the gas supply unit 40 into the first space S 1 where the substrate W is provided in order to deposit a precursor on the substrate W. In other words, the precursor gas is supplied to the substrate W. The precursor gas is also supplied into the second space S 2 via the first space S 1 .

When the film DF is a silicon oxide film, the precursor gas is, e.g., an aminosilane-based gas. The aminosilane-based gas may be an organic-containing aminosilane-based gas. As for the aminosilane-based gas, a gas having a molecular structure with a relatively small number of amino groups may be used. For example, monoamino silane (H 3 —Si—R (R being an organic group that contains an organic group and may be substituted)) may be used. The aminosilane-based gas may contain aminosilane having one to three silicon atoms, or may contain aminosilane having one to three amino groups. The aminosilane having one to three silicon atoms may be monosilane (monoaminosilane) having one to three amino groups, disilane having one to three amino groups, or trisilane having one to three amino groups. The aminosilane may have an amino group that may be substituted. Further, the amino group may be substituted by any of a methyl group, an ethyl group, a propyl group, and a butyl group. The methyl group, the ethyl group, the propyl group, and the butyl group may be substituted with halogen.

When the film DF is a tungsten film, the precursor gas contains tungsten. The precursor gas may be a halogenated tungsten gas. The precursor gas is, e.g., tungsten hexafluoride (WF 6 ) gas. The precursor gas may be another halogenated tungsten gas such as tungsten hexachloride gas, or another tungsten-containing gas.

In the step ST 11 , no plasma is generated in the first space S 1 . In other words, in the step ST 11 , the supply of the first high frequency power and the second high frequency power is stopped. In the step ST 11 , the gas exhaust unit 52 is controlled to set a pressure in the first space S 1 to a specified pressure. In the step ST 11 , a carrier gas may be supplied together with the precursor gas from the gas supply unit 40 into the first space S 1 . The carrier gas is also supplied into the second space S 2 via the first space S 1 . The carrier gas may be a rare gas such as He gas, Ne gas, Ar gas, Xe gas, or Kr gas. In one embodiment, the carrier gas may be supplied into the first space S 1 and the second space S 2 during the execution of the film formation DP. When the step ST 11 is executed, the precursor is adsorbed onto the surface of the substrate W. The precursor is also adsorbed onto the first surface F 1 or the film CF extending on the first surface F 1 and onto the film CF extending on the second surface F 2 .

Next, in the step ST 12 , the inner space S is purged. Specifically, in the step ST 12 , the inner space S is exhausted. In the step ST 12 , a carrier gas may be supplied as a purge gas into the first space S 1 and the second space S 2 . By executing the step ST 12 , the precursor gas in the inner space S is discharged, and the precursor excessively deposited on the substrate W is removed.

Next, in the step ST 13 , a reactant gas that reacts with the precursor is supplied from the gas supply unit 40 into the first space S 1 . When the film DF is a silicon oxide film, the reactant gas is an oxygen-containing gas. The oxygen-containing gas is oxygen gas (O 2 gas), carbon monoxide gas, or carbon dioxide gas. When the film DF is a tungsten film, the reactant gas is hydrogen gas (H 2 gas).

In the step ST 13 , plasma of the reactant gas is generated in the first space S 1 . In the step ST 13 , the first high frequency power is supplied to the upper electrode 30 in a state where the reactant gas is supplied into the first space S 1 . Accordingly, plasma of the reactant gas is generated in the first space S 1 . In the step ST 13 , the second high frequency power may be supplied to the lower electrode 18 . In the step ST 13 , the gas exhaust unit 52 is controlled to set a pressure in the first space S 1 to a specified pressure. In the step ST 13 , active species from the plasma react with the precursor. When the film DF is a silicon oxide film, the precursor is oxidized by the reaction between active species of oxygen and the precursor. When the film DF is a tungsten film, impurities in the precursor are removed by the reaction between active species of hydrogen and the precursor. When the precursor gas is a halogenated tungsten gas, halogen elements are removed from the precursor by the reaction between the halogen elements in the precursor and hydrogen. The active species, mainly radicals, from the plasma reach the second space S 2 from the first space S 1 . Therefore, the reaction between the active species and the precursor extending on the second surface F 2 occurs.

Next, in the step ST 14 , the inner space S is purged. Specifically, in the step ST 14 , the inner space S is exhausted. In the step ST 14 , a carrier gas may be supplied as a purge gas into the first space S 1 and the second space S 2 . By executing the step ST 14 , the reactant gas in the inner space S is discharged.

Next, in the step ST 15 , it is determined whether or not stop conditions are satisfied. It is determined that the stop conditions are satisfied when the number of executions of the cycle CY has reached a predetermined number. The predetermined number is greater than or equal to one. If it is determined in the step ST 15 that the stop conditions are not satisfied, the cycle CY is executed again. On the other hand, when it is determined in the step ST 15 that the stopping conditions are satisfied, the film formation DP is stopped. By performing the film formation DP, a film DF is formed on the surface of the substrate W as shown in FIG. 14A . The film DF formed on the surface of the substrate W includes a first region R 1 and a second region R 2 . The first region R 1 extends along a side wall surface SW of the mask MK which defines the opening OMK. The second region R 2 extends on the underlying film UF. By performing the film formation DP, the deposit DS made of the same material as that forming the film DF is formed on the first surface F 1 and also formed on the film CF extending on the second surface F 2 .

As shown in FIG. 13 , in the step STR, the step ST 16 is then executed. In the step ST 16 , plasma etching of the film DF is performed to remove the second region R 2 without removing the first region R 1 . In the step ST 16 , the processing gas is supplied into the first space S 1 in a state where the substrate W in the state shown in FIG. 14A is mounted on the supporting table 16 (the electrostatic chuck 20 ). The processing gas used in the step ST 16 may contain a fluorocarbon gas. In the step ST 16 , the gas exhaust unit 52 is controlled to set a pressure in the first space S 1 to a specified pressure. In the step ST 16 , the first high frequency power from the first high frequency power supply 61 is supplied to the upper electrode 30 . In the step ST 16 , anisotropic plasma etching is performed to selectively remove the second region R 2 with respect to the first region R 1 . Therefore, in the step ST 16 , the second high frequency power from the second high frequency power supply 62 is supplied to the lower electrode 18 . By executing the step ST 16 , plasma of the processing gas is generated in the first space S 1 . Then, ions in the plasma are attracted into the substrate W, thereby etching the second region R 2 . As a result, as shown in FIG. 14B , the first region R 1 of the film DF remains and the second region R 2 is etched. The film DF extending on the upper surface of the mask MK is removed, or the film thickness thereof is reduced.

In the step STR, the film DF is formed on the surface of the substrate W by the deposition of the precursor (step ST 11 ) and the reaction between the active species from the plasma and the precursor (step ST 13 ). Then, in the step ST 16 , the film DF is etched without removing the first region R 1 . As a result, the width of the opening OMK of the mask MK is adjusted.

While various embodiments have been described, various modifications can be made without being limited to the above-described embodiments. For example, the plasma processing apparatus used in the method MT may be an inductively coupled plasma processing apparatus, or a plasma processing apparatus that excites a gas using a surface wave such as a microwave.

While the present disclosure has been shown and described with respect to the embodiments, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the scope of the present disclosure as defined in the following claims.