Semiconductor manufacturing apparatus and semiconductor device manufacturing method

Abstract

To provide a semiconductor manufacturing apparatus capable of removing an oxide film by dry cleaning.SOLUTION: According to an embodiment, a semiconductor-manufacturing apparatus includes a chamber 2 used for forming an oxide film, a susceptor 3 that is provided in the chamber and on which a substrate is placed, at least one supply pipe P1 for supplying a gas to the chamber, an exhaust pipe PP3 for exhausting a gas from the chamber, and a control unit 12 that controls supplying of a first source gas, an oxidizing gas, a reducing gas activated by plasma, and a first halide gas activated by plasma to the chamber and exhausting from the chamber.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] FIELD Embodiments of the present invention relate to a semiconductor manufacturing apparatus and a method for manufacturing a semiconductor device. [Background technology]

[0002] Chemical vapor deposition (CVD) equipment is one type of semiconductor manufacturing equipment. In CVD equipment, dry cleaning is sometimes performed without opening the chamber to the atmosphere to reduce downtime during chamber cleaning. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 3771879 [Patent Document 2] Japanese Patent Application Laid-Open No. 2006-60167 [Patent Document 3] Japanese Patent Application Laid-Open No. 2002-60951 Summary of the Invention [Problem to be solved by the invention]

[0004] An embodiment of the present invention can provide a semiconductor manufacturing device that can remove an oxide film by dry cleaning. [Means for solving the problem]

[0005] The semiconductor manufacturing apparatus according to the embodiment includes a chamber used to form an oxide film, a susceptor provided within the chamber on which a substrate is placed, at least one supply pipe for supplying gas to the chamber, an exhaust pipe for exhausting gas from the chamber, and a control unit for controlling the supply of a first source gas, an oxidizing gas, a plasma-activated reducing gas, and a plasma-activated first halide gas to the chamber, and the exhaust from the chamber. [Brief explanation of the drawings]

[0006] [Figure 1] FIG. 1 is a configuration diagram of a semiconductor manufacturing apparatus according to a first embodiment. [Figure 2] 4 is a flowchart of a film formation process in the semiconductor manufacturing apparatus according to the first embodiment. [Figure 3] FIG. 2 is a conceptual diagram of a cleaning process in the semiconductor manufacturing apparatus according to the first embodiment. [Figure 4] A table showing the bond energy between each element and oxygen. [Figure 5] 4 is a flowchart of a cleaning process in the semiconductor manufacturing apparatus according to the first embodiment. [Figure 6] 4 is a flowchart of a cleaning process in the semiconductor manufacturing apparatus according to the first embodiment. [Figure 7] 7 is a timing chart showing process conditions in each step of FIGS. 5 and 6; [Figure 8] FIG. 10 is a configuration diagram of a semiconductor manufacturing apparatus according to a first example of the second embodiment. [Figure 9] FIG. 10 is a configuration diagram of a semiconductor manufacturing apparatus according to a second example of the second embodiment. [Figure 10] 10 is a flowchart of a cleaning process in the semiconductor manufacturing apparatus according to the third embodiment. [Figure 11] 10 is a flowchart of a cleaning process in the semiconductor manufacturing apparatus according to the third embodiment. [Figure 12] FIG. 10 is a configuration diagram of a semiconductor manufacturing apparatus according to a fourth embodiment. [Figure 13] 1 is a table showing the bond energies of In, Ga, and Zn with halogen elements. [Figure 14] 10 is a flowchart of a cleaning process in a semiconductor manufacturing apparatus according to a fourth embodiment. [Figure 15] 10 is a flowchart of a cleaning process in a semiconductor manufacturing apparatus according to a fourth embodiment. [Figure 16] 16 is a timing chart showing process conditions in each step of FIGS. 14 and 15. [Figure 17] FIG. 13 is a configuration diagram of a semiconductor manufacturing apparatus according to a first example of the fifth embodiment. [Figure 18] FIG. 13 is a configuration diagram of a semiconductor manufacturing apparatus according to a second example of the fifth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0007] Hereinafter, embodiments will be described with reference to the drawings. In the following description, components having substantially the same functions and configurations will be designated by the same reference numerals, and repeated explanations will be provided only when necessary. Furthermore, each embodiment shown below exemplifies an apparatus or method for embodying the technical concept of the embodiment, and the embodiments do not specify the materials, shapes, structures, arrangements, etc. of the components as described below.

[0008] 1. First embodiment A semiconductor manufacturing apparatus according to a first embodiment will be described. Hereinafter, a CVD apparatus for forming an oxide film will be described as the semiconductor manufacturing apparatus. Hereinafter, an ALD (Atomic Layer Deposition) apparatus for forming InGaZnO (hereinafter also referred to as "IGZO"), which is composed of indium (In), gallium (Ga), zinc (Zn), and oxygen (O), will be described. Note that the oxide film formed by the CVD apparatus is not limited to InGaZnO. Alternatively, the oxide film formed by the CVD apparatus may be, but is not limited to, a metal oxide film, a conductive metal oxide film, or an oxide semiconductor. Furthermore, the CVD apparatus is not limited to an ALD apparatus. For example, the CVD apparatus may be an LPCVD (Low Pressure Chemical Vapor Deposition) apparatus or a plasma CVD apparatus. In the following description, dry cleaning, which is performed without opening the chamber to the atmosphere, will be simply referred to as "cleaning."

[0009] 1.1 Configuration First, an example of a semiconductor manufacturing apparatus will be described with reference to Fig. 1. Fig. 1 is a configuration diagram of the semiconductor manufacturing apparatus 1. Note that in the example of Fig. 1, some of the connections between the components of the semiconductor manufacturing apparatus 1 are indicated by arrows, but the connections between the components are not limited to this.

[0010] As shown in FIG. 1, the semiconductor manufacturing apparatus 1 includes a chamber 2, a susceptor 3, a shower head 4, a heating unit 5, a plasma generator 6, a vacuum device 7, a piping heater 8, a water detection system 9, a high vacuum device 10, an abatement device 11, a control unit 12, a throttle valve (or butterfly valve) TV, valves VB1 to VB13, supply piping P1 to P5 and P7 to P9, and piping PP1 to PP5.

[0011] The chamber 2 is a processing chamber used for film formation. For example, the internal pressure of the chamber 2 is maintained at a low pressure (a pressure lower than atmospheric pressure). The chamber 2 is provided with an exhaust port 2e for exhausting gas inside the chamber 2. The chamber 2 may be configured to be able to raise and lower the temperature of the inner wall of the chamber 2 using a temperature control mechanism (e.g., a chiller, etc.) not shown. For example, the chamber 2 is controlled at an appropriate temperature to prevent by-products from the film formation process and cleaning process from adhering to the inner wall of the chamber 2.

[0012] A semiconductor substrate is placed on the susceptor 3. For example, a gate valve (not shown) is provided in the chamber 2. The semiconductor substrate is transferred from the outside of the chamber 2 onto the susceptor 3 via the gate valve. The susceptor 3 may have a mechanism for lifting up the semiconductor substrate. For example, the susceptor 3 is attached to the lower surface of the inner wall of the chamber 2. For example, a heater is provided inside the susceptor 3. The temperature of the susceptor 3 is controlled based on the process conditions of the film formation process and the cleaning process.

[0013] The showerhead 4 is used for diffusing gas. The showerhead 4 is attached to the top of the chamber 2. More specifically, the showerhead 4 is disposed so that its lower surface, from which gas is emitted, faces the upper surface of the susceptor 3, i.e., the semiconductor substrate placed on the susceptor 3. A gas inlet is provided at the top of the showerhead 4. Multiple holes for discharging gas are formed at the bottom of the showerhead 4. In the example of FIG. 1, gas is supplied to the showerhead 4, i.e., the chamber 2, via a supply pipe P1 and a valve VB1. For example, a source gas is supplied to the showerhead 4 via a supply pipe P2, a valve VB2, a supply pipe P1, and a valve VB1. An oxidizing gas is supplied to the showerhead 4 via a supply pipe P3, a valve VB3, a supply pipe P1, and a valve VB1. For example, oxygen (O2) or ozone (O3) is supplied as the oxidizing gas. Nitrogen (N2) is supplied to the shower head 4 via the supply pipe P4, the valve VB4, the supply pipe P1, and the valve VB1. Hydrogen (H2) is supplied to the shower head 4 via the supply pipe P5, the valve VB5, the supply pipe P1, and the valve VB1. Note that multiple gases may be supplied to the chamber 2 simultaneously. Furthermore, the shower head 4 may be provided with a heater to efficiently clean the shower head 4.

[0014] Note that multiple source gas supply pipes P2 may be provided depending on the type of source gas. For example, in the case of InGaZnO, an In-containing organic source, a Ga-containing organic source, and a Zn-containing organic source are used as source gases. In this case, three systems of source gas supply pipes P2 and valves VB2 are provided. More specifically, a supply pipe P2 and valve VB2 corresponding to the In-containing organic source, a supply pipe P2 and valve VB2 corresponding to the Ga-containing organic source, and a supply pipe P2 and valve VB2 corresponding to the Zn-containing organic source are provided. Furthermore, the source gas supply pipe P2 may be capable of being heated by a heating mechanism (not shown). For example, when the source gas is a vaporized gas of a liquid raw material, the supply pipe P2 may be heated to an appropriate temperature to prevent liquefaction midway through the pipe.

[0015] In this embodiment, a heating unit 5 is provided on the H2 supply pipe P5 upstream of the valve VB5. The heating unit 5 heats H2. That is, the heating unit 5 supplies heated H2 gas (hereinafter also referred to as "high-temperature H2") to the chamber 2. For example, high-temperature H2 is used to purge moisture from the chamber 2 during a cleaning process. By using the heating unit 5, purging with high-temperature H2 can be performed regardless of the temperature of the susceptor 3.

[0016] The plasma generator 6 is a device that generates plasma discharge outside the chamber 2. Hereinafter, generating plasma discharge is also referred to as "turning plasma on." The plasma generator 6 is also called a remote plasma device. The plasma generator 6 has a chamber inside that generates plasma discharge. The plasma generator 6 activates gas supplied to the plasma generator 6 with plasma to generate radicals. Argon (Ar) is supplied to the plasma generator 6 via a supply pipe P7 and a valve VB7. For example, H2 is supplied as a reducing gas via a supply pipe P8 and a valve VB8. For example, nitrogen trifluoride (NF3) is supplied as a cleaning gas via a supply pipe P9 and a valve VB9. Note that a gas containing at least one halogen element, such as fluorine (F), chlorine (Cl), bromine (Br), or iodine (I), i.e., a halide gas, may be used as the cleaning gas (etching gas). More specifically, for example, at least one of F2, HF, SF6, BCl3, Cl2, HCl, ClF3, Br2, HBr, I2, and HI may be used as the halide gas. For example, in order to suppress the accumulation of by-products due to thermal decomposition in the exhaust pipe PP3, etc., the cleaning gas is preferably a material that has a relatively high bond energy with the etching target. In this case, it is desirable to use plasma as an energy source for activating the cleaning gas.

[0017] The plasma generator 6 is connected to the chamber 2 via a pipe PP1 and a valve VB6. The plasma generator 6 is also connected to an exhaust pipe PP3 via a valve VB10, a bypass pipe PP2, and a valve VB11. For example, when activated gas (radicals) is to be supplied to the chamber 2 by the plasma generator 6, the valve VB6 is opened, and the valves VB10 and VB11 are closed. On the other hand, when activated gas (radicals) is not to be supplied to the chamber 2 by the plasma generator 6, the valve VB6 is closed, and the valves VB10 and VB11 are opened.

[0018] An exhaust pipe PP3 is connected to an exhaust port 2e of the chamber 2 via a throttle valve TV. The throttle valve TV is capable of adjusting the opening of the valve and is used to control the pressure in the chamber 2.

[0019] The exhaust pipe PP3 is connected to a vacuum device 7. The vacuum device 7 exhausts gas from the chamber 2 via the exhaust pipe PP3 and a throttle valve TV. The configuration of the vacuum device 7 depends on the process conditions of the film formation process and the cleaning process. For example, the vacuum device 7 may be configured such that a mechanical booster pump is provided upstream of the exhaust gas and a dry pump is provided downstream.

[0020] A pipe heater 8 is attached to cover the exhaust pipe PP3. The pipe heater 8 controls the pipe temperature of the exhaust pipe PP3. The exhaust pipe PP3 is controlled to an appropriate temperature by the pipe heater 8 to prevent by-products from adhering to it.

[0021] A bypass pipe PP4 is connected to the exhaust pipe PP3 via a valve VB12 provided upstream of the exhaust pipe PP3 and a valve VB13 provided downstream of the exhaust pipe PP3. A water detection system 9 and a high vacuum device 10 are connected to the bypass pipe PP4.

[0022] The water detection system 9 is a system that detects water contained in exhaust gas. For example, the water detection system 9 may include an analyzer that uses the FT-IR (Fourier Transform Infrared Spectroscopy) method or an analyzer that uses the NDIR (Non Dispersive InfraRed) method.

[0023] For example, when the water detection system 9 analyzes the moisture content of the exhaust gas, the valves VB12 and VB13 are opened, which allows a portion of the exhaust gas to be introduced into the bypass pipe PP4.

[0024] The high vacuum device 10 is a vacuum device capable of reaching a higher ultimate vacuum (lower pressure) than the vacuum device 7. For example, the high vacuum device 10 is a turbomolecular pump. For example, the high vacuum device 10 can be used when it is desired to more efficiently evacuate gas (and water) from the chamber 2.

[0025] The detoxification device 11 is a device that removes substances (harmful substances) contained in the exhaust gas. The detoxification device 11 is connected to the gas exhaust port of the vacuum device 7 via a pipe PP5. The detoxification device 11 may be of a combustion type, a wet type, or a dry type.

[0026] The control unit 12 controls the entire semiconductor manufacturing apparatus 1. More specifically, the control unit 12 controls the susceptor 3, the heating unit 5, the plasma generation device 6, the vacuum device 7, the piping heater 8, the water detection system 9, the high vacuum device 10, and the abatement device 11.

[0027] The control unit 12 controls the throttle valve TV and the valves VB1 to VB13. The control unit 12 also controls the supply amount of each gas, thereby controlling the supply and exhaust of gas to the chamber 2.

[0028] The control unit 12 controls a gate valve (not shown), a semiconductor substrate transport mechanism, etc. In this way, the loading and unloading of semiconductor substrates into and out of the chamber 2 is controlled.

[0029] The control unit 12 controls the entire semiconductor manufacturing apparatus 1 to execute the film forming process and the cleaning process.

[0030] The valves VB1 to VB13 are, for example, air valves, and the control unit 12 controls the opening and closing of the valves.

[0031] 1.2 Film formation process Next, an example of a film formation process in the semiconductor manufacturing apparatus 1 will be described with reference to Fig. 2. Fig. 2 is a flowchart of the film formation process.

[0032] 2, first, the control unit 12 loads a semiconductor substrate (also referred to as a "wafer") into the chamber 2 (step S1). The semiconductor substrate is placed on the susceptor 3.

[0033] The control unit 12 starts the film formation process with the semiconductor substrate placed on the susceptor 3. Below, ALD using multiple source gases will be described using InGaZnO as an example. In the following description, the total number of source gases is N (N is an integer equal to or greater than 1). Each source gas is represented as the nth source gas using a variable n (n is an integer satisfying 1≦n≦N). For example, in the case of InGaZnO, an In-containing organic source, a Ga-containing organic source, and a Zn-containing organic source are used. Therefore, N=3. For example, the In-containing organic source is the first source gas (n=1). The Ga-containing organic source is the second source gas (n=2). The Zn-containing organic source is the third source gas (n=3). The order of the first to third source gases may be reversed.

[0034] The control unit 12 sets the variable n=1 (step S2).

[0035] The control unit 12 supplies the nth source gas to the chamber 2 (step S3). For example, when n=1, an organic source containing In is supplied. When n=2, an organic source containing Ga is supplied. When n=3, an organic source containing Zn is supplied. More specifically, the control unit 12 opens the valve VB1 and the valve VB2 corresponding to the nth source gas to supply the nth source gas to the chamber 2. At this time, the control unit 12 adjusts the throttle valve TV to control the pressure inside the chamber 2. The exhaust gas is exhausted to the vacuum device 7.

[0036] Next, the control unit 12 stops the supply of the nth source gas and exhausts the remaining source gas in the chamber 2 (step S4). More specifically, the control unit 12 closes the valve VB1 and the valve VB2 corresponding to the nth source gas to stop the supply of the nth source gas to the chamber 2. In this state, the remaining source gas in the chamber 2 is exhausted to the vacuum device 7.

[0037] Next, the control unit 12 supplies the oxidizing gas to the chamber 2 (step S5). More specifically, the control unit 12 opens the valves VB1 and VB3 to supply the oxidizing gas to the chamber 2. At this time, the control unit 12 adjusts the throttle valve TV to control the pressure inside the chamber 2. The exhaust gas is exhausted to the vacuum device 7.

[0038] Next, the control unit 12 stops the supply of the oxidizing gas and exhausts the residual oxidizing gas from the chamber 2 (step S6). More specifically, the control unit 12 closes the valves VB1 and VB3 to stop the supply of the oxidizing gas to the chamber 2. In this state, the residual oxidizing gas from the chamber 2 is exhausted to the vacuum device 7.

[0039] Next, the control unit 12 checks whether the variable n has reached the total number N of types of source gases (step S7).

[0040] If n=N is not satisfied (step S7_No), that is, if the variable n has not reached the total number N of source gas types, the control unit 12 increments the variable n to n=n+1 (step S8). Thereafter, the control unit 12 proceeds to step S3.

[0041] If n=N (Yes in step S7), that is, if the variable n reaches the total number N of source gas types, one film formation loop is completed. For example, a thin film of InGaZnO (for example, one to several molecular layers) for one film formation loop is formed on a semiconductor substrate.

[0042] Although the plurality of source gases are supplied the same number of times here, this is not limiting. For example, the number of times the first source gas is supplied may be different from the number of times the second source gas is supplied.

[0043] Next, the control unit 12 checks whether the number of film formation loops has reached a preset number (step S9), that is, whether the thickness of the InGaZnO film has reached a target thickness.

[0044] If the number of film formation loops has not reached the preset number of loops (step S9_No), the control unit 12 proceeds to step S1. On the other hand, if the number of film formation loops has reached the preset number of loops (step S9_Yes), the control unit 12 ends the film formation process.

[0045] The control unit 12 unloads the semiconductor substrate from the chamber 2 (step S10).

[0046] 1.3 Cleaning Process 1.3.1 Cleaning Process Overview First, an overview of the cleaning process will be described with reference to Fig. 3. Fig. 3 is a conceptual diagram of the cleaning process.

[0047] 3, for example, after the oxide film 100 deposition process, the oxide film 100 adheres to at least a part of the surface of the susceptor 3 and the inner wall of the chamber 2. A cleaning process is performed to remove the oxide film 100.

[0048] The cleaning process includes a reduction treatment process and an etching process. In the cleaning process, the control unit 12 repeatedly executes a cleaning loop including the reduction treatment process and the etching process. That is, the reduction treatment process and the etching process are repeatedly executed alternately.

[0049] The reduction treatment process is a process for reducing (desorbing oxygen from) the surface of the oxide film 100. More specifically, the plasma generator 6 generates H plasma to generate hydrogen radicals (H * , * denotes a radical). The plasma generator 6 supplies hydrogen radicals to the chamber 2. The hydrogen radicals combine with oxygen near the surface of the oxide film 100 to form water (HO) or OH. The water (or OH) is desorbed from the oxide film 100 and exhausted from the chamber 2. As a result, a modified layer 101 that has been modified by the reduction treatment (oxygen has been desorbed) is formed on the surface of the oxide film 100. In other words, the reduction treatment process is a process for forming the modified layer 101.

[0050] The etching process is a process for etching the modified layer 101. More specifically, the plasma generator 6 generates NF3 plasma to generate fluorine radicals (F * ) is generated. The plasma generator 6 supplies fluorine radicals to the chamber 2. The modified layer 101 is etched by the fluorine radicals. The reduction treatment process (formation of the modified layer 101) and the etching process are repeated until the oxide film 100 on at least a part of the surface of the susceptor 3 and the inner wall of the chamber 2 is removed.

[0051] 1.3.2 Elements of oxide film Next, an example of the constituent elements of the oxide film to which the cleaning process of this embodiment is applied will be described with reference to Fig. 4. Fig. 4 is a table showing the bond energy between each element and oxygen.

[0052] This embodiment is applicable to cleaning oxide films containing elements that have a relatively low bond energy with oxygen and are easily reduced by H2 plasma (hydrogen radicals).

[0053] 4, an oxide film containing Ga and an element having a lower bond energy with oxygen than Ga is easily reduced by H2 plasma. More specifically, an oxide film containing oxygen (O) and at least one of xenon (Xe), thallium (Tl), fluorine (F), silver (Ag), gold (Au), iodine (I), cadmium (Cd), bromine (Br), palladium (Pd), zinc (Zn), mercury (Hg), sodium (Na), rubidium (Rb), copper (Cu), cesium (Cs), bismuth (Bi), lithium (Li), indium (In), magnesium (Mg), manganese (Mn), nickel (Ni), and gallium (Ga) as constituent elements is easily reduced.

[0054] For example, InGaZnO is suitable as a film to which the present cleaning process is applied, since all of its constituent elements, In, Ga, and Zn, are easily reduced. Note that the oxide film to be cleaned is not limited to a conductive oxide film, and any oxide film containing an element with low oxygen bonding energy may be used.

[0055] 1.3.3 Cleaning process flow Next, an example of the cleaning process will be described with reference to FIGS. 5 to 7. FIGS. 5 and 6 are flowcharts of the cleaning process. In the example of FIGS. 5 and 6, a case will be described in which a loop of the reduction process including the reduction process and Ar purging is repeatedly performed in the reduction process. For example, even if the reduction process is performed for the same time period, repeating the reduction process and purging in short increments can more effectively remove water remaining in the chamber 2. This can prevent water from reattaching to the oxide film 100, allowing the reduction process of the oxide film to be performed more effectively. The reduction process may be performed one or more times.

[0056] FIG. 7 is a timing chart showing the process conditions for each step in FIGS. 5 and 6. In FIG. 7, the vertical axes of Ar, H2, NF3, and high-temperature H2 indicate the gas supply rate. However, the scale of the vertical axis differs depending on the gas. The vertical axis of plasma indicates whether the plasma is on or off in the plasma generator 6. The vertical axis of pressure indicates the pressure in the chamber 2. The vertical axis of chamber temperature indicates the measured temperature in the chamber 2. For example, the chamber temperature is the temperature measured by a thermocouple installed in the wall of the chamber 2 or the temperature measured by a thermometer installed in the susceptor 3. The vertical axis of exhaust pipe temperature is, for example, the temperature measured at the exhaust pipe PP3. Note that the vertical axis scales of the chamber temperature and the exhaust pipe temperature are different. The vertical axes of VB12 and VB13 indicate whether the valves VB12 and VB13 are open or closed. Note that some steps are omitted in the example of FIG. 7.

[0057] [S11] When performing a cleaning process after the film formation process, the control unit 12 first changes the temperature of the exhaust pipe PP3, as shown in FIG. 5. More specifically, the control unit 12 changes the temperature of the exhaust pipe PP3 (piping heater 8) from the set temperature for the film formation process to the set temperature for the cleaning process. In the example of FIG. 7, the temperature of the exhaust pipe PP3 is lowered. For example, if the temperature of the exhaust pipe PP3 is relatively high during the cleaning process, the exhaust gas containing the etched modified layer 101 may be decomposed by the heat of the exhaust pipe PP3, resulting in the formation of by-products. In order to prevent by-products from adhering to the exhaust pipe PP3, the temperature of the exhaust pipe PP3 during the cleaning process may be set lower than that during the film formation process. Note that if changing the temperature of the exhaust pipe PP3 is not necessary, this step may be omitted.

[0058] In the example of Fig. 7, Ar is supplied to the chamber 2. More specifically, the control unit 12 opens the valves VB6 and VB7. In this state, the control unit 12 supplies Ar to the chamber 2 via the plasma generator 6. Note that N2 may be used instead of Ar. In this case, the control unit 12 opens the valves VB1 and VB4.

[0059] For example, the control unit 12 sets the opening of the throttle valve TV to 100%. Therefore, the pressure in the chamber 2 is based on the flow rate of Ar.

[0060] [S12] As shown in FIG. 5, the control unit 12 changes the temperature inside the chamber. More specifically, the control unit 12 changes the set temperature of the temperature control mechanism (chiller) that adjusts the temperature of the heater inside the susceptor 3 and / or the inner wall of the chamber 2 from the set temperature for the film formation process to the set temperature for the cleaning process. In the example of FIG. 7, the temperature inside the chamber is lowered. The heat capacity of the susceptor 3 and the chamber 2 is greater than that of the exhaust pipe PP3. Therefore, the time required for temperature stabilization in step S12 may be longer than the time required for temperature stabilization in step S11. For example, the temperature stabilization in the chamber may take several tens of minutes to several hours. Note that if a change in the temperature inside the chamber is not required, this step may be omitted. Steps S11 and S12 may be performed simultaneously, or step S12 may be performed first.

[0061] In the example of Fig. 7, the flow rate of Ar is increased from step S11 in order to remove dust from the chamber 2. Note that N2 may be used instead of Ar. For example, the control unit 12 sets the opening of the throttle valve TV to 100%. Therefore, the pressure in the chamber 2 increases in accordance with the increase in the flow rate of Ar.

[0062] [S13] Steps S13 to S16 correspond to the reduction treatment process.

[0063] As shown in FIG. 5, the plasma generator 6 turns on the plasma. Step S13 is a step for stabilizing the plasma discharge. In the example of FIG. 7, the flow rate of Ar is reduced from the flow rate of Ar in step S12. The control unit 12 adjusts the flow rate of Ar to a flow rate suitable for plasma discharge. In this state, the plasma generator 6 turns on the plasma.

[0064] For example, the control unit 12 sets the opening of the throttle valve TV to 100%, so that the pressure in the chamber 2 decreases as the flow rate of Ar decreases.

[0065] [S14] As shown in FIG. 5, the plasma generator 6 generates H plasma. This performs a reduction process. Specifically, as shown in FIG. 7, the plasma generator 6 maintains the plasma ON state. In this state, the control unit 12 opens the valves VB6, VB7, and VB8 to supply Ar and H to the plasma generator 6. This causes the plasma generator 6 to generate H plasma. The plasma generator 6 generates hydrogen radicals from the H plasma. The plasma generator 6 supplies hydrogen radicals (i.e., hydrogen activated by the plasma) to the chamber 2. This performs a reduction process, forming a modified layer 101. Water generated in the chamber 2 by the reduction process is exhausted to the vacuum device 7 via the exhaust pipe PP3. At this time, the control unit 12 opens the valves VB12 and VB13. The control unit 12 uses the high-vacuum device 10 to more efficiently exhaust water from the chamber 2. Using the high-vacuum device 10 prevents water from reattaching to the oxide film 100 in the chamber 2. The control unit 12 may add a step after step S14, for example, to open the valves VB12 and VB13 while stopping the supply of Ar and H2.

[0066] The water detection system 9 detects water contained in the exhaust gas while the valves VB12 and VB13 are open. The control unit 12 may change the execution time of the reduction process, i.e., the time of step S14, based on the detected water level.

[0067] For example, the control unit 12 sets the opening of the throttle valve TV to 100%. Therefore, the pressure in the chamber 2 increases from step S13 as the supply of H2 starts.

[0068] After step S14 is completed, the plasma generator 6 stops the plasma discharge (turns the plasma off).

[0069] [S15] As shown in FIG. 5, the control unit 12 executes an Ar purge. This purges the water in the chamber 2. Specifically, as shown in FIG. 7, the control unit 12 closes the valves VB12 and VB13 of the bypass pipe PP4. In this state, for example, the control unit 12 increases the flow rate of Ar supplied to the chamber 2. In the example of FIG. 7, H2 continues to be supplied. For example, the control unit 12 sets the opening of the throttle valve TV to 100%. Therefore, the pressure in the chamber 2 increases as the flow rate of Ar increases. That is, the pressure in the chamber 2 in step S15 is higher than that in step S14.

[0070] The control unit 12 may connect (bypass) the plasma generator 6 to the exhaust pipe PP3 using the bypass pipe PP2 without turning off the plasma in the plasma generator 6. More specifically, the valve VB6 is closed and the valves VB10 and VB11 are opened. In this case, an Ar supply pipe may be connected to the valve VB1 so that Ar is supplied to the chamber 2 via VB1. Alternatively, the control unit 12 may open the valves VB1 and VB4 to perform N2 purging.

[0071] [S16] As shown in Fig. 5, the control unit 12 determines whether to terminate the reduction treatment process. For example, the determination by the control unit 12 is based on the water detection value by the water detection system 9 and the upper limit number of loops of the reduction treatment process. More specifically, for example, if the water detection value is equal to or greater than a set value and the number of loops of the reduction treatment process has not reached the upper limit, the control unit 12 determines to execute the loop of the reduction treatment process again. That is, the control unit 12 determines not to terminate the reduction treatment process (step S16_No). On the other hand, if the water detection value is less than the set value, or if the water detection value is equal to or greater than the set value but the number of loops of the reduction treatment process has reached the upper limit, the control unit 12 determines to terminate the reduction treatment process (step S16_Yes).

[0072] When the control unit 12 determines not to end the reduction treatment process (step S16_No), the control unit 12 proceeds to step S13. That is, the reduction treatment process loop is executed again. Note that when the plasma generator 6 and the exhaust pipe PP3 are bypassed, the plasma generator 6 maintains the plasma in the on state, so the control unit 12 proceeds to step S14.

[0073] When the control unit 12 determines that the reduction treatment process is to be ended (step S16_Yes), the control unit 12 proceeds to step S17. Note that, when the detected water value is equal to or greater than the set value but the number of loops of the reduction treatment process has reached the upper limit, the control unit 12 may proceed to the next step S17, or may display an alarm on the monitor screen and end the cleaning process, for example.

[0074] [S17] As shown in FIG. 5, the control unit 12 performs purging using high-temperature H2 and Ar. This removes water remaining in the chamber 2. Specifically, as shown in FIG. 7, the plasma generator 6 turns off the plasma. In this state, the control unit 12 opens valves VB6 and VB7 to supply Ar to the chamber 2. Furthermore, the control unit 12 opens valves VB1 and VB5 to supply high-temperature H2 to the chamber 2. In the example of FIG. 7, step S17 is further divided into three steps S17a to S17c.

[0075] The flow rates of Ar and high-temperature H2 in step S17a are relatively low. For example, the control unit 12 sets the opening of the throttle valve TV to 100%. Therefore, the pressure in the chamber 2 is based on the flow rates of Ar and high-temperature H2. The control unit 12 opens the valves VB12 and VB13. The control unit 12 uses the high-vacuum device 10 to more efficiently evacuate water from the chamber 2.

[0076] In step S17b, the control unit 12 increases the flow rates of Ar and high-temperature H2. As the flow rates of Ar and high-temperature H2 increase, the pressure in the chamber 2 also increases. By increasing the pressure in the chamber 2, water remaining in the chamber 2 can be more effectively removed. The control unit 12 closes the valves VB12 and VB13.

[0077] In step S17c, the control unit 12 reduces the flow rates of Ar and high-temperature H2. As the flow rates of Ar and high-temperature H2 decrease, the pressure in the chamber 2 also decreases. The control unit 12 opens the valves VB12 and VB13. The control unit 12 uses the high-vacuum device 10 to more efficiently evacuate water from the chamber 2.

[0078] In step S17, the control unit 12 may open the valve VB8 to further supply H2.

[0079] [S18] As shown in FIG. 5, the control unit 12 uses Ar to purge the chamber 2 and the plasma generator 6. This removes residual H2 from the chamber 2 and the plasma generator 6. For example, if NF3 plasma is generated while H2 remains, HF may be formed, potentially corroding pipes and the like. Therefore, the control unit 12 performs Ar purging to remove residual H2 from the chamber 2 and the plasma generator 6 before generating NF3 plasma. Specifically, as shown in FIG. 7, the control unit 12 closes valves VB1 and VB5 to stop the supply of high-temperature H2. The control unit 12 increases the flow rate of Ar. In this state, for example, the control unit 12 adjusts the opening of the throttle valve TV to increase the pressure in the chamber 2. This effectively removes residual H2 from the chamber 2 and the plasma generator 6.

[0080] [S19] Steps S19 to S22 correspond to the etching process.

[0081] As shown in Figure 6, the plasma generator 6 turns on the plasma. Like step S13, step S19 is a step for stabilizing the plasma discharge. Note that the pressure in the chamber 2 in step S19 is preferably higher than the pressure in the chamber 2 in step S13. For example, the reduction treatment is preferably performed at a relatively low pressure to prevent re-adhesion of water in the chamber 2, and the etching is preferably performed at a pressure higher than that of the reduction treatment process to diffuse (fill) the etching gas into the chamber 2.

[0082] 7, the control unit 12 reduces the flow rate of Ar to, for example, the same flow rate as in step S13 in order to stabilize the plasma discharge in the plasma generator 6. In this state, the plasma generator 6 turns on the plasma. The pressure in the chamber 2 is maintained at a relatively high pressure by controlling the throttle valve TV, as in step S18.

[0083] [S20] As shown in FIG. 6, the plasma generator 6 generates NF3 plasma. This performs etching. Specifically, as shown in FIG. 7, the plasma generator 6 maintains the plasma ON state. In this state, the control unit 12 opens the valves VB6, VB7, and VB9 to supply Ar and NF3 to the plasma generator 6. This causes the plasma generator 6 to generate NF3 plasma. The plasma generator 6 generates fluorine radicals from the NF3 plasma. The plasma generator 6 supplies fluorine radicals (i.e., halide gas activated by plasma) to the chamber 2. This performs etching of the modified layer 101. The exhaust gas from the etching is exhausted to the vacuum device 7 via the exhaust pipe PP3. The pressure in the chamber 2 is maintained at a relatively high pressure by controlling the throttle valve TV, as in step S18.

[0084] After step S20 is completed, the plasma generator 6 turns off the plasma.

[0085] [S21] As shown in Fig. 6, the control unit 12 executes an Ar purge. This removes F from the chamber 2 and the plasma generator 6. Specifically, as shown in Fig. 7, the control unit 12 closes the valve VB9 to stop the supply of NF3. In this state, the control unit 12 increases the flow rate of Ar supplied to the chamber 2, for example. For example, the control unit 12 sets the opening of the throttle valve TV to 100%. Therefore, the pressure in the chamber 2 is based on the flow rate of Ar.

[0086] [S22] As shown in FIG. 6, the control unit 12 checks whether the number of cleaning loops has reached a preset number.

[0087] If the number of cleaning loops has not reached the preset number (step S22_No), the control unit 12 proceeds to step S13. On the other hand, if the number of cleaning loops has reached the preset number (step S22_Yes), the control unit 12 proceeds to step S23.

[0088] The control unit 12 may change the times of the reduction treatment process (step S14) and the etching process (step S20) when repeating the cleaning loop. For example, in order to reduce damage to the chamber 2, the susceptor 3, etc. due to cleaning, the times of the reduction treatment process and the etching process may be shortened each time the loop is repeated.

[0089] [S23] As shown in FIG. 6, the control unit 12 performs purging using high-temperature H2 and Ar. This removes F remaining in the chamber 2. Specifically, as shown in FIG. 7, the plasma generation device 6 turns off the plasma. In this state, the control unit 12 opens valves VB6 and VB7 to supply Ar to the chamber 2. Furthermore, the control unit 12 opens valves VB1 and VB5 to supply high-temperature H2 to the chamber 2. In the example of FIG. 7, step S23 is further divided into three steps S23a to S23c. As in steps S17a to S17c, the flow rates of Ar and high-temperature H2 are varied in steps S23a to S23c. Note that in step S23, the control unit 12 closes valves VB12 and VB13.

[0090] In step S23, the control unit 12 may further open the valve VB8 to supply H2.

[0091] [S24] As shown in FIG. 6, the control unit 12 executes the formation of a coating film. The coating film is a film that protects the surface of the susceptor 3. For example, a silicon oxide film (SiO2) or alumina (Al2O3) can be used as the coating film. The semiconductor manufacturing apparatus 1 can have a configuration for forming the coating film. For example, the semiconductor manufacturing apparatus 1 may have a supply line for a source gas for the coating film, or may have a configuration for applying plasma to the chamber 2.

[0092] 1.4 Effects of this embodiment The configuration according to this embodiment makes it possible to provide a semiconductor manufacturing apparatus capable of removing oxide films by dry cleaning.

[0093] For example, in semiconductor manufacturing equipment (CVD equipment) that deposits conductive metal oxide films, such as InGaZnO, which are difficult to etch with halide gases, the chamber is opened to the atmosphere and manual wet cleaning is performed. When the chamber is opened to the atmosphere, the equipment downtime due to cleaning increases, which means the equipment's operating rate decreases.

[0094] In contrast, with the configuration according to this embodiment, the semiconductor manufacturing equipment can perform reduction treatment and etching in the cleaning process. The reduction treatment can remove oxygen from the surface of the oxide film. In other words, the oxide film can be modified. The modified layer can be removed by dry etching using a halide gas. Therefore, by repeating the reduction treatment process and the etching process in the cleaning process, dry cleaning of the oxide film can be performed. This allows the chamber to be cleaned without being exposed to the atmosphere. This reduces the downtime of the equipment. In other words, the availability rate of the equipment can be improved.

[0095] Furthermore, the configuration according to this embodiment can be applied to a semiconductor manufacturing apparatus that forms an oxide film containing Ga and an element that has a smaller bond energy with oxygen than Ga. This allows for effective reduction of the oxide film using hydrogen radicals.

[0096] The present embodiment is not limited to semiconductor manufacturing equipment that forms a conductive oxide film, but can also be applied to semiconductor manufacturing equipment that forms an oxide film containing Ga and an element that has a smaller bond energy with oxygen than Ga.

[0097] 2. Second embodiment Next, a second embodiment will be described. In the second embodiment, two examples of the configuration of the semiconductor manufacturing apparatus 1 will be shown. The following description will focus on the differences from the first embodiment.

[0098] 2.1 First Example An example of a semiconductor manufacturing apparatus will be described with reference to Fig. 8. Fig. 8 is a configuration diagram of a semiconductor manufacturing apparatus 1.

[0099] As shown in FIG. 8, a plasma generator 6 is connected upstream of a supply pipe P1. The plasma generator 6 is connected to a showerhead 4 via the supply pipe P1 and a valve VB1. A supply pipe P10 is also connected to the plasma generator 6. A source gas, an oxidizing gas, N2, high-temperature H2, Ar, H2, and NF3 are supplied to the plasma generator 6 via the supply pipe P10. More specifically, a source gas is supplied to the plasma generator 6 via the supply pipe P2, a valve VB2, and a supply pipe P10. An oxidizing gas is supplied to the plasma generator 6 via the supply pipe P3, a valve VB3, and a supply pipe P10. N2 is supplied to the plasma generator 6 via the supply pipe P4, a valve VB4, and a supply pipe P10. H2 is supplied to the plasma generator 6 via a heating unit 5, a supply pipe P5, a valve VB5, and a supply pipe P10. Ar is supplied to the plasma generator 6 via supply pipe P7, valve VB7, and supply pipe P10. H2 is supplied to the plasma generator 6 via supply pipe P8, valve VB8, and supply pipe P10. NF3 is supplied to the plasma generator 6 via supply pipe P9, valve VB9, and supply pipe P10. Each gas supplied to the plasma generator 6 is supplied to the chamber 2 via supply pipe P1, valve VB1, and showerhead 4.

[0100] Therefore, in this example, the source gas, the oxidizing gas, and the reducing gas (H2) and halide gas (NF3) activated by the plasma generator 6 are supplied to the chamber 2 (shower head 4) via one supply pipe P1.

[0101] In this example, the valves VB6, VB10, and VB11, the pipe PP1, and the bypass pipe PP2 present in the first embodiment are not present. Note that a bypass pipe PP2 may be provided to connect the plasma generator 6 and the exhaust pipe PP3. Also, the valve VB8 and the H2 supply pipe connected to the valve VB8 may be eliminated. The other configurations are the same as those of the first embodiment.

[0102] 2.2 Second Example An example of a semiconductor manufacturing apparatus will be described with reference to Fig. 9. Fig. 9 is a configuration diagram of a semiconductor manufacturing apparatus 1.

[0103] As shown in Fig. 9, the heating unit 5, which is provided upstream of the valve VB5 in Fig. 1 of the first embodiment, is provided upstream of the valve VB8. In this case, the valve VB5 and the H2 supply pipe connected to the valve VB5 may be omitted. The other configurations are the same as those of the first embodiment.

[0104] 2.3 Effects of this embodiment The configuration according to this embodiment provides the same effects as those of the first embodiment.

[0105] Furthermore, with the configuration according to the first example, cleaning gas can be supplied to the shower head 4. Therefore, the oxide film adhering to the inside of the shower head 4 can be removed.

[0106] Furthermore, with the configuration according to the second example, high-temperature H2 can be supplied to the plasma generator 6. Therefore, purging inside the plasma generator 6 can be performed more efficiently.

[0107] 3. Third embodiment Next, a third embodiment will be described. In the third embodiment, a cleaning process flow different from that of the first embodiment will be described. The following description will focus on the differences from the first embodiment.

[0108] 3.1 Cleaning process flow An example of the cleaning process will be described with reference to Figures 10 and 11. Figures 10 and 11 are flow charts of the cleaning process.

[0109] As shown in FIG. 10, in step S13, the plasma generator 6 turns on the plasma, as in the first embodiment.

[0110] [S30] As shown in FIG. 10, the plasma generator 6 starts discharging H2 plasma. This starts the reduction process. More specifically, the plasma generator 6 maintains the plasma in an ON state. In this state, the control unit 12 starts supplying H2 and Ar to the plasma generator 6 under the same conditions as in step S14 of the first embodiment. This causes the plasma generator 6 to start discharging H2 plasma. That is, the reduction process starts. At this time, the water detection system 9 starts detecting water contained in the exhaust gas.

[0111] [S31] As shown in Figure 10, the water detection system 9 monitors the water contained in the exhaust gas during the reduction process (during H2 plasma discharge). The control unit 12 determines whether to terminate the reduction process based on the detected water level. The reduction process (H2 plasma discharge) continues until the detected water level falls below a set value.

[0112] [S32] When the detected water level falls below the set value (step S31_Yes), the control unit 12 ends the reduction process. That is, the plasma generator 6 turns off the plasma. In this embodiment, the water detection system 9 functions as an endpoint detection system for the reduction process.

[0113] When the reduction process is completed, the control unit 12 proceeds to step S15. Then, when step S15 is completed, the control unit 12 proceeds to step S17. The subsequent steps are the same as those in the first embodiment.

[0114] 3.2 Effects of this embodiment The configuration according to this embodiment provides the same effects as those of the first embodiment.

[0115] Furthermore, with the configuration according to this embodiment, the water detection system 9 can be used as an endpoint detection system for the reduction treatment, thereby optimizing the time for the reduction treatment.

[0116] It should be noted that this embodiment may be applied to the configuration according to the second embodiment.

[0117] 4. Fourth embodiment Next, a fourth embodiment will be described. The fourth embodiment describes a cleaning process including multiple etching processes using different cleaning gases containing different halogen elements. The following description will focus on differences from the first to third embodiments.

[0118] 4.1 Configuration First, an example of the semiconductor manufacturing apparatus 1 will be described with reference to Fig. 12. Fig. 12 is a configuration diagram of the semiconductor manufacturing apparatus 1.

[0119] As shown in Fig. 12, Ar, H2, O2, and two cleaning gases A and B are supplied to the plasma generating device 6 of this embodiment. The other configurations are the same as those of the first embodiment shown in Fig. 1. The number of cleaning gases is not limited to two. There may be three or more types of cleaning gases.

[0120] More specifically, Ar is supplied to the plasma generator 6 via a supply pipe P7 and a valve VB7. A reducing gas, for example, H2, is supplied to the plasma generator 6 via a supply pipe P8 and a valve VB8. An oxidizing gas, for example, O2, is supplied to the plasma generator 6 via a supply pipe P21 and a valve VB21. A cleaning gas A is supplied to the plasma generator 6 via a supply pipe P22 and a valve VB22. A cleaning gas B is supplied to the plasma generator 6 via a supply pipe P23 and a valve VB23.

[0121] Cleaning gases A and B are halide gases each containing a different halogen element (F, Cl, Br, and I). For example, when cleaning gas A contains iodine (I) as a halogen element, cleaning gas B contains at least one of fluorine (F), chlorine (Cl), and bromine (Br) as a halogen element, excluding iodine (I). For example, a halide gas containing fluorine (F) is F2, HF, or SF6. For example, a halide gas containing chlorine (Cl) is BCl3, Cl2, or HCl. For example, a halide gas containing fluorine (F) and chlorine (Cl) is ClF3. For example, a halide gas containing bromine (Br) is HBr, Br2, or BBr3. For example, a halide gas containing iodine (I) is I2 or HI. Note that the combination of halide gases selected as cleaning gases A and B may be arbitrary. For example, cleaning gas A may contain iodine (I) and cleaning gas B may contain chlorine (Cl), or cleaning gas A may contain chlorine (Cl) and cleaning gas B may contain iodine (I).

[0122] In the cleaning process, the semiconductor manufacturing apparatus 1 of this embodiment executes a reduction treatment process, a first etching process using cleaning gas A, and a second etching process using cleaning gas B. Details of the first and second etching processes will be described later.

[0123] 4.2 Bond energies of In, Ga, and Zn with halogen elements Next, the bond energies of In, Ga, and Zn with halogen elements will be described with reference to Fig. 13. In, Ga, and Zn are constituent elements of the oxide film (InGaZnO) to which the cleaning process of this embodiment is applied. In other words, In, Ga, and Zn are elements to be etched. Fig. 13 is a table showing the bond energies of In, Ga, and Zn with halogen elements.

[0124] As shown in FIG. 13 , when comparing the bond energies of In, Ga, and Zn with halogen elements, the relationship is F>Cl>Br>I, regardless of In, Ga, or Zn. That is, iodine (I) has a lower bond energy with the element being etched than other halogen elements. Therefore, when InGaZnO is etched using a cleaning gas containing iodine (I) as the halogen element, the etching rate tends to be higher than when cleaning gases containing other halogen elements are used. Therefore, when InGaZnO is etched using a cleaning gas containing iodine (I) as the halogen element, the etching time can be shortened compared to when cleaning gases containing other halogen elements are used. However, because iodine (I) has a lower bond energy with the element being etched than other halogen elements, etching by-products tend to reattach in the chamber 2, exhaust pipe PP3, etc. Furthermore, when InGaZnO is etched using a cleaning gas containing fluorine (F) as the halogen element, the etching rate tends to be lower than when cleaning gases containing other halogen elements are used. However, since fluorine (F) has a higher bond energy with the element to be etched than other halogen elements, etching by-products are less likely to reattach in the chamber 2, exhaust pipe PP3, etc. Thus, etching characteristics (etching rate, by-products generated, possibility of by-product reattachment, etc.) differ depending on the halogen element.

[0125] 4.3 Cleaning Process Next, the cleaning process will be described. The cleaning process of this embodiment includes a reduction treatment process, a first etching process, and a second etching process. In the cleaning process, the control unit 12 repeatedly executes a cleaning loop including the reduction treatment process, the first etching process, and the second etching process.

[0126] The reduction treatment process is the same as in the first embodiment.

[0127] The first etching process is a process for etching the modified layer 101 using cleaning gas A. In the plasma generating device 6, radicals of halogen elements are generated using cleaning gas A.

[0128] The second etching process is a process of etching the modified layer 101 using cleaning gas B. In the plasma generating device 6, radicals of halogen elements are generated using cleaning gas B. The second etching process is performed after the first etching process.

[0129] In this embodiment, taking note of the fact that etching characteristics differ depending on the halogen element, halide gases containing different halogen elements are used as cleaning gases A and B. For example, when priority is given to shortening the etching time, a halide gas containing iodine (I) is selected as cleaning gas A. Then, for example, a halide gas containing chlorine (Cl) is selected as cleaning gas B. Furthermore, when priority is given to suppressing redeposition of etching by-products, for example, a halide gas containing chlorine (Cl) is selected as cleaning gas A. Then, for example, a halide gas containing iodine (I) is selected as cleaning gas B. For example, by using a halide gas containing iodine (I) in the second etching process, by-products redeposited on the exhaust pipe PP3 or the like can be removed.

[0130] In the present embodiment, a case where a halide gas containing iodine (I) is selected as the cleaning gas A and a halide gas containing chlorine (Cl) is selected as the cleaning gas B will be described below.

[0131] As in the first embodiment, a cleaning loop including a reduction treatment process, a first etching process, and a second etching process is repeatedly performed until the oxide film 100 on at least a part of the surface of the susceptor 3 and the inner wall of the chamber 2 is removed.

[0132] 4.4 Cleaning process flow Next, an example of a cleaning process will be described with reference to FIGS. 14 to 16. FIGS. 14 and 15 are flowcharts of the cleaning process. FIG. 16 is a timing chart showing the process conditions for each step in FIGS. 14 and 15. In FIG. 16, the vertical axes of Ar, H2, cleaning gas A, cleaning gas B, O2, and high-temperature H2 indicate the gas supply amount. However, the scale of the vertical axis differs depending on the gas. The vertical axis of plasma indicates whether the plasma is in the on state or off state in the plasma generating device 6. The vertical axis of pressure indicates the pressure in the chamber 2. The vertical axis of temperature in the chamber indicates the measured temperature in the chamber 2. Note that the vertical axes of the temperature in the chamber and the exhaust pipe temperature have different scales. The vertical axes of VB12 and VB13 indicate whether the valves VB12 and VB13 are open or closed. Note that some steps are omitted in the example of FIG. 16.

[0133] [S11]~[S18] As shown in Fig. 14, the flow from step S11 to step S18 is the same as that explained in the first embodiment using Fig. 5. Steps S13 to S16 correspond to the reduction treatment process.

[0134] [S40] Steps S40 to S45 correspond to the first etching process.

[0135] 15, after step S18 is completed, the plasma generator 6 turns on the plasma. Like step S13, step S40 is a step for stabilizing the plasma discharge. Note that the pressure in the chamber 2 in step S40 is preferably higher than the pressure in the chamber 2 in step S13. For example, etching is preferably performed at a higher pressure than the reduction treatment process in order to diffuse (fill) the etching gas into the chamber 2.

[0136] 16, the control unit 12 reduces the flow rate of Ar to, for example, the same flow rate as in step S13 in order to stabilize the plasma discharge in the plasma generator 6. In this state, the plasma generator 6 turns on the plasma. The pressure in the chamber 2 is maintained at a relatively high pressure by controlling the throttle valve TV, as in step S18.

[0137] [S41] As shown in FIG. 15, the plasma generator 6 generates plasma of the cleaning gas A. This performs etching. Specifically, as shown in FIG. 16, the plasma generator 6 maintains the plasma ON state. In this state, the control unit 12 opens the valves VB6, VB7, and VB22 to supply Ar and the cleaning gas A to the plasma generator 6. This causes the plasma generator 6 to generate plasma of the cleaning gas A. The plasma generator 6 generates halogen radicals from the plasma of the cleaning gas A. For example, if the cleaning gas A contains iodine (I), iodine (I) radicals are generated. The plasma generator 6 supplies halogen radicals (i.e., halide gas activated by the plasma) to the chamber 2. This performs etching of the modified layer 101. The exhaust gas from the etching is exhausted to the vacuum device 7 via the exhaust pipe PP3. The pressure in the chamber 2 is maintained at a relatively high pressure by controlling the throttle valve TV, as in step S18.

[0138] After step S41 is completed, the plasma generator 6 turns off the plasma.

[0139] [S42] As shown in Fig. 15, the control unit 12 executes Ar purge. As a result, the cleaning gas A remaining in the chamber 2 and the plasma generator 6 is exhausted. Specifically, as shown in Fig. 16, the control unit 12 closes the valve VB22 to stop the supply of the cleaning gas A. In this state, the control unit 12 increases the flow rate of Ar supplied to the chamber 2, for example. For example, the control unit 12 sets the opening of the throttle valve TV to 100%. Therefore, the pressure in the chamber 2 is based on the flow rate of Ar.

[0140] [S43] As shown in FIG. 15, the control unit 12 performs plasma purging with H2 to remove residues from the chamber 2. The plasma purging may be performed in a reducing atmosphere or an oxidizing atmosphere. For example, when the cleaning gas contains fluorine (F) or iodine (I), plasma purging in a reducing atmosphere is preferable. For example, in the case of plasma purging using H2, halogen elements are bonded with hydrogen (H) and removed as HF, HI, HCl, HBr, or the like. In this example, since cleaning gas A contains iodine (I), plasma purging with H2 is applied.

[0141] 16, step S43 includes two steps S43a and S43b. In step S43a, the plasma generator 6 turns off the plasma. At this time, the control unit 12 can control the flow rate of Ar and the pressure in the chamber 2 to the same extent as in the reduction treatment process of step S13.

[0142] Next, in step S43b, the control unit 12 further opens the valve VB8 to supply Ar and H2 to the plasma generator 6. As a result, the plasma generator 6 generates H2 plasma. The plasma generator 6 generates hydrogen radicals from the H2 plasma. The plasma generator 6 supplies the hydrogen radicals to the chamber 2. As a result, plasma purging is performed.

[0143] [S44] As shown in Fig. 15, the control unit 12 performs an Ar purge. Specifically, as shown in Fig. 16, for example, the control unit 12 performs an Ar purge under the same conditions as in step S15.

[0144] [S45] As shown in Fig. 15, the control unit 12 performs purging using high-temperature H2 and Ar. Specifically, as shown in Fig. 16, the plasma generation device 6 turns off the plasma. In this state, the control unit 12 opens valves VB6 and VB7 to supply Ar to the chamber 2. Furthermore, the control unit 12 opens valves VB1 and VB5 to supply high-temperature H2 to the chamber 2. In the example of Fig. 7, step S45 is further divided into three steps S45a to S45c.

[0145] The flow rates of Ar and high-temperature H2 in step S45a are relatively low. For example, the control unit 12 sets the opening of the throttle valve TV to 100%. Therefore, the pressure in the chamber 2 is based on the flow rates of Ar and high-temperature H2. Note that the control unit 12 may open the valves VB12 and VB13, as in step S17a.

[0146] In step S45b, the control unit 12 increases the flow rates of Ar and high-temperature H2. As the flow rates of Ar and high-temperature H2 increase, the pressure in the chamber 2 also increases.

[0147] In step S45c, the control unit 12 reduces the flow rates of Ar and high-temperature H2. As the flow rates of Ar and high-temperature H2 decrease, the pressure in the chamber 2 also decreases. Note that the control unit 12 may open the valves VB12 and VB13, similar to step S17c.

[0148] In step S45, the control unit 12 may open the valve VB8 to further supply H2.

[0149] [S46] Steps S46 to S51 correspond to the second etching process.

[0150] As shown in Fig. 15, after step S45 is completed, the plasma generator 6 turns on the plasma. As shown in Fig. 16, the processing conditions in step S46 are the same as those in step S40.

[0151] [S47] As shown in FIG. 15, the plasma generator 6 generates plasma of cleaning gas B. This performs etching. Specifically, as shown in FIG. 16, the plasma generator 6 maintains the plasma ON state. In this state, the control unit 12 opens valves VB6, VB7, and VB23 to supply Ar and cleaning gas B to the plasma generator 6. This causes the plasma generator 6 to generate plasma of cleaning gas B. The plasma generator 6 generates halogen radicals from the plasma of cleaning gas B. For example, if cleaning gas B contains chlorine (Cl), chlorine (Cl) radicals are generated. The plasma generator 6 supplies halogen radicals (i.e., halide gas activated by plasma) to the chamber 2. The pressure in the chamber 2 is maintained at a relatively high pressure by controlling the throttle valve TV, as in step S41.

[0152] After step S47 is completed, the plasma generator 6 turns off the plasma.

[0153] [S48] As shown in Fig. 15, the control unit 12 executes Ar purge. This causes the cleaning gas B remaining in the chamber 2 and the plasma generator 6 to be exhausted. Specifically, as shown in Fig. 16, the control unit 12 closes the valve VB23 to stop the supply of the cleaning gas B. In this state, the control unit 12 increases the flow rate of Ar supplied to the chamber 2, for example. For example, the control unit 12 sets the opening of the throttle valve TV to 100%. Therefore, the pressure in the chamber 2 is based on the flow rate of Ar.

[0154] [S49] 15, the control unit 12 performs O2 plasma purging to remove residues in the chamber 2. For example, if the residue removal in the first etching process (step S43) is performed in a reducing atmosphere, the residue removal in the second etching process can be performed in an oxidizing atmosphere to remove halogen elements that cannot be completely removed in a reducing atmosphere. For example, in the case of plasma purging using O2, fluorine (F) and chlorine (Cl) are removed as OF2 and ClO.

[0155] 16, step S49 includes two steps S49a and S49b. In step S49a, the plasma generator 6 turns off the plasma. At this time, the control unit 12 can control the flow rate of Ar and the pressure in the chamber 2 to the same extent as in the plasma purge in step S43.

[0156] Next, in step S49b, the control unit 12 further opens the valve VB21 to supply Ar and O2 to the plasma generator 6. As a result, the plasma generator 6 generates O2 plasma. The plasma generator 6 generates oxygen radicals from the O2 plasma. The plasma generator 6 supplies the oxygen radicals to the chamber 2. As a result, plasma purging is performed.

[0157] [S50] As shown in Fig. 15, the control unit 12 performs an Ar purge. Specifically, as shown in Fig. 16, for example, the control unit 12 performs an Ar purge under the same conditions as in step S44.

[0158] [S51] As shown in Fig. 15, the control unit 12 performs purging using high-temperature H2 and Ar. Specifically, as shown in Fig. 16, for example, the control unit 12 performs purging using high-temperature H2 and Ar under the same conditions as in step S45.

[0159] [S52] As shown in FIG. 15, the control unit 12 checks whether the number of cleaning loops has reached a preset number.

[0160] If the number of cleaning loops has not reached the preset number (step S52_No), the control unit 12 proceeds to step S13. On the other hand, if the number of cleaning loops has reached the preset number (step S52_Yes), the control unit 12 proceeds to step S53.

[0161] When repeating the cleaning loop, the control unit 12 may change the times of the reduction treatment process (step S14), the first etching process (step S41), and the second etching process (step S47).

[0162] [S53] 15, the control unit 12 executes the formation of the coating film. The conditions for forming the coating film are the same as those in step S24 of the first embodiment.

[0163] 4.5 Effects of this embodiment The configuration according to this embodiment provides the same effects as those of the first embodiment.

[0164] Furthermore, with the configuration according to this embodiment, multiple etching processes can be performed using different halide gases containing different halogen elements. Each halogen element has a different bond energy with the element to be etched. Therefore, etching characteristics such as the etching rate, the type of etching by-products, and the reattachment of the by-products vary depending on the halogen element contained in the cleaning gas. Therefore, by performing multiple etching processes using halide gases containing different halogen elements, the cleaning process can be performed more effectively.

[0165] 4.6 Modification of the fourth embodiment Next, a first modified example and a second modified example of the fourth embodiment will be described.

[0166] 4.6.1 First variant First, a first modified example of the fourth embodiment will be described. In the fourth embodiment, the reduction treatment process is the same as that described in FIG. 5 of the first embodiment, but is not limited to this. For example, the reduction treatment process may be the same as that described in FIG. 10 of the third embodiment.

[0167] 4.6.1 Second variant Next, a second modified example of the fourth embodiment will be described, in which a cleaning process (cleaning loop) includes three or more etching processes.

[0168] First, a case where the cleaning process includes three etching processes will be described. More specifically, three cleaning gases A, B, and C containing different halogen elements are supplied to the plasma generator 6. The halogen elements contained in the cleaning gases A, B, and C may be selected in ascending or descending order of their bond energy with the element to be etched. For example, iodine (I), bromine (Br), and chlorine (Cl) may be selected as the halogen elements contained in the cleaning gases A, B, and C, respectively. In the cleaning process, the semiconductor manufacturing apparatus 1 successively performs a first etching process using the cleaning gas A, a second etching process using the cleaning gas B, and a third etching process using the cleaning gas C.

[0169] Next, a case where the cleaning process includes four etching processes will be described. More specifically, four cleaning gases A, B, C, and D containing different halogen elements are supplied to the plasma generator 6. The halogen elements contained in the cleaning gases A, B, C, and D may be selected in ascending or descending order of their bond energy with the element to be etched. For example, iodine (I), bromine (Br), chlorine (Cl), and fluorine (F) may be selected as the halogen elements contained in the cleaning gases A, B, C, and D, respectively. In the cleaning process, the semiconductor manufacturing apparatus 1 successively performs a first etching process using the cleaning gas A, a second etching process using the cleaning gas B, a third etching process using the cleaning gas C, and a fourth etching process using the cleaning gas D.

[0170] 5. Fifth embodiment Next, a fifth embodiment will be described. In the fifth embodiment, two examples of the configuration of the semiconductor manufacturing apparatus 1 will be shown. The following description will focus on the differences from the first to fourth embodiments.

[0171] 5.1 First Example A first example of the fifth embodiment will be described with reference to Fig. 17. In the first example of the fifth embodiment, a case will be described in which the cleaning process described in the fourth embodiment is applied to the semiconductor manufacturing apparatus 1 described in the first example of the second embodiment with reference to Fig. 8. Fig. 17 is a configuration diagram of the semiconductor manufacturing apparatus 1.

[0172] 17, in this example, cleaning gas A, cleaning gas B, source gas, oxidizing gas, N2, high-temperature H2, Ar, and H2 are supplied to plasma generator 6. That is, in this example, the source gas, oxidizing gas, and reducing gas (H2) and halide gas (cleaning gases A and B) activated by plasma generator 6 are supplied to chamber 2 (shower head 4) via one supply pipe P1. The other configuration is the same as that of the first example of the second embodiment shown in FIG. 8.

[0173] 5.2 Second Example A second example of the fifth embodiment will be described with reference to Fig. 18. In the second example of the fifth embodiment, a case will be described in which the cleaning process described in the fourth embodiment is applied to the semiconductor manufacturing apparatus 1 described in the second example of the second embodiment with reference to Fig. 9. Fig. 18 is a configuration diagram of the semiconductor manufacturing apparatus 1.

[0174] 18, in this example, O2, cleaning gas A, cleaning gas B, Ar, and high-temperature H2 are supplied to a plasma generating device 6. Other configurations are similar to those in FIG. 9 of the second example of the second embodiment.

[0175] 5.3 Effects of this embodiment The configuration according to this embodiment provides the same effects as those of the first to fourth embodiments.

[0176] 6. Modifications, etc. The semiconductor manufacturing apparatus according to the above embodiment includes a chamber (2) used to form an oxide film, a susceptor (3) provided in the chamber and on which a substrate is placed, at least one supply pipe (P1) for supplying gas to the chamber, an exhaust pipe (PP3) for exhausting gas from the chamber, and a control unit (12) for controlling the supply of a first source gas (such as In), an oxidizing gas (O), a plasma-activated reducing gas (H), and a plasma-activated first halide gas (NF) to the chamber, and the exhaust from the chamber.

[0177] The embodiment is not limited to the above-described embodiment, and various modifications are possible.

[0178] In the above embodiment, the semiconductor manufacturing apparatus 1 is described as a CVD apparatus for forming a conductive metal oxide film, but the present invention is not limited to this. The semiconductor manufacturing apparatus 1 may be a film forming apparatus other than a CVD apparatus, or may be an etching apparatus.

[0179] The embodiments are merely examples, and the scope of the invention is not limited thereto. [Explanation of symbols]

[0180] 1...semiconductor manufacturing equipment, 2...chamber, 2e...exhaust port, 3...susceptor, 4...shower head, 5...heating unit, 6...plasma generator, 7...vacuum device, 8...piping heater, 9...water detection system, 10...high vacuum device, 11...detoxification device, 100...oxide film, 101...modified layer, P1 to P5, P7 to P10, P21 to P23...supply pipe, PP1 to PP5...piping, VB1 to VB13, VB21 to VB23...valve

Claims

1. a chamber used for forming an oxide film; a susceptor provided in the chamber and on which a substrate is placed; at least one supply line for supplying gas to the chamber; an exhaust pipe for exhausting gas from the chamber; a control unit that controls the supply of a first source gas, an oxidizing gas, a plasma-activated reducing gas, and a plasma-activated first halide gas to the chamber, and the exhaust of the gas from the chamber; Equipped with Semiconductor manufacturing equipment.

2. the first source gas includes at least one of Xe, Tl, F, Ag, Au, I, Cd, Br, Pd, Zn, Hg, Na, Rb, Cu, Cs, Bi, Li, In, Mg, Mn, Ni, and Ga; The semiconductor manufacturing apparatus according to claim 1 .

3. The control unit controls the supply of a second source gas, which is different from the first source gas, to the chamber. The semiconductor manufacturing apparatus according to claim 1 .

4. The first halide gas is NF ３ , F ２ , HF, SF ６ , BCl ３ , Cl ２ , HCl, ClF ３ ,Br ２ , HBr, I ２ and HI, The semiconductor manufacturing apparatus according to claim 1 .

5. The supply of the reducing gas and the supply of the first halide gas are alternately and repeatedly performed. The semiconductor manufacturing apparatus according to claim 1 .

6. a water detection system connected to the exhaust pipe for detecting water contained in the exhaust gas from the chamber; The semiconductor manufacturing apparatus according to claim 1 .

7. Further comprising a heating unit for heating hydrogen; supplying the heated hydrogen to the chamber; The semiconductor manufacturing apparatus according to claim 1 .

8. The control unit controls the supply of a second halide gas activated by plasma and containing a halogen element different from that of the first halide gas into the chamber. The semiconductor manufacturing apparatus according to claim 1 .

9. a loop including the supply of the reducing gas, the supply of the first halide gas, and the supply of the second halide gas is repeatedly executed; The semiconductor manufacturing apparatus according to claim 8 .

10. A substrate is carried into a chamber having an inner wall; After the substrate is loaded, a first source gas and an oxidizing gas are supplied to the chamber to form an oxide film on the substrate; The substrate on which the oxide film is formed is carried out of the chamber; After the substrate is removed, an activated reducing gas is supplied to the chamber; supplying an activated first halide gas into the chamber after supplying the reducing gas; A method for manufacturing a semiconductor device.

11. the supply of the reducing gas and the supply of the first halide gas are alternately and repeatedly performed; The method for manufacturing a semiconductor device according to claim 10.

12. After the supply of the reducing gas is started, water contained in the exhaust gas from the chamber is detected, If the detected amount of water is equal to or greater than a preset value, the supply of the reducing gas is resumed. The method for manufacturing a semiconductor device according to claim 10.

13. the oxide film adhering to the inner wall during the formation of the oxide film is reduced by the activated reducing gas. The method for manufacturing a semiconductor device according to claim 10.

14. the reduced oxide film is etched by the activated first halide gas; The method for manufacturing a semiconductor device according to claim 13.

15. The oxide film contains at least one of Xe, Tl, F, Ag, Au, I, Cd, Br, Pd, Zn, Hg, Na, Rb, Cu, Cs, Bi, Li, In, Mg, Mn, Ni, and Ga, and O. The method for manufacturing a semiconductor device according to claim 10.

16. The oxide film is InGaZnO. The method for manufacturing a semiconductor device according to claim 15.

17. The first halide gas is NF ３ , F ２ , HF, SF ６ , BCl ３ , Cl ２ , HCl, ClF ３ ,Br ２ , HBr, I ２ and HI, The method for manufacturing a semiconductor device according to claim 14.

18. After the supply of the reducing gas, heated hydrogen is supplied to the chamber. The method for manufacturing a semiconductor device according to claim 10.

19. supplying, into the chamber, a second halide gas that is activated and contains a halogen element different from that of the first halide gas, after the first halide gas has been supplied; The method for manufacturing a semiconductor device according to claim 10.

20. a loop including the supply of the reducing gas, the supply of the first halide gas, and the supply of the second halide gas is repeatedly executed; The method for manufacturing a semiconductor device according to claim 19.

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