JP2012134311A - Semiconductor device manufacturing method and substrate processing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To inhibit oxidation of an underlying electrode when a metal oxide film is formed by using a strongly oxidative oxygen-containing gas.SOLUTION: A step of forming a first metal oxide layer 510 immediately above an electrode 610 by performing: a step of supplying at least one type of metal content gas in a processing chamber and discharging the gas to form an absorption layer of the metal content gas on an electrode 610 and a step of subsequently supplying a first oxygen-containing gas in the processing chamber; and a step of forming a second metal oxide layer 560 on the first metal oxide layer 510 by performing: a step of supplying the metal content gas in the processing chamber and discharging the gas to form an absorption layer of the metal content gas on the first metal oxide layer 510 and a step of subsequently supplying a second oxygen-containing gas having an oxidation power stronger than that of the first oxygen-containing gas in the processing chamber; are sequentially performed in this order.

Description

  The present invention relates to a semiconductor device manufacturing method and a substrate processing apparatus.

  In order to promote high integration and high performance of a MOSFET (Metal-Oxide-Semiconductor Field Effect Transistor), a metal oxide film (High-k film) having a high dielectric constant such as an HfO film (hafnium oxide film) is used as a gate insulating film. And a high-k / metal gate structure in which the gate electrode is formed of a metal film such as a TiN film (titanium nitride film) has been studied.

  In a DRAM (Dynamic Random Access Memory), a MIM (Metal Insulator Metal) is formed by sandwiching a capacitor insulating film formed of a metal oxide film such as an HfO film from above and below with a capacitor electrode formed of a metal film such as a TiN film. ) Adoption of a capacitor having a structure is being studied.

  The metal oxide film constituting the gate insulating film and the capacitor insulating film can be formed by, for example, a CVD (Chemical Vapor Deposition) method or an ALD (Atomic Layer Deposition) method. That is, it can be formed by supplying a metal-containing gas and an oxygen-containing gas into a processing chamber containing a substrate.

However, when a metal oxide film is formed using O ₃ (ozone) gas or the like having a strong oxidizing power as an oxygen-containing gas, the underlying gate electrode and capacitor electrode (hereinafter also simply referred to as “electrode”) are oxidized by the oxygen-containing gas. As a result, a low dielectric constant layer is formed on the surface, leading to an increase in EOT (equivalent oxide film thickness). As a result, the electrical characteristics of the semiconductor device may be deteriorated.

  It is also conceivable to form the electrode using a metal such as Ru (ruthenium) so as to suppress oxidation by the oxygen-containing gas. However, Ru is an expensive metal and causes an increase in manufacturing cost. Further, a technique for forming a high-quality Ru film has not been established, and it is difficult to adopt Ru as an electrode material also from this aspect.

  The present invention provides a method for manufacturing a semiconductor device and a substrate processing apparatus capable of suppressing oxidation of an underlying electrode when a metal oxide film is formed using an oxygen-containing gas having strong oxidizing power. Objective.

  In one embodiment of the present invention, a substrate carrying-in step of carrying a substrate on which an electrode is formed into a processing chamber, a metal oxide film forming step of forming a metal oxide film directly on the electrode of the substrate, and the metal oxide film A substrate unloading step of unloading the formed substrate from the processing chamber, and in the metal oxide film forming step, supplying at least one metal-containing gas into the processing chamber; Supplying a first oxygen-containing gas, forming a first metal oxide layer on the electrode, supplying the metal-containing gas into the processing chamber, and And supplying a second oxygen-containing gas having a stronger oxidizing power than the first oxygen-containing gas into the processing chamber to form a second metal oxide layer on the first metal oxide layer. A semiconductor device for sequentially performing the second step. It is a method of manufacture.

  According to another aspect of the present invention, there is provided a processing chamber that houses a substrate on which an electrode is formed, a metal-containing gas supply system that supplies at least one metal-containing gas into the processing chamber, and a first oxygen in the processing chamber. A first oxygen-containing gas supply system for supplying a containing gas; and a second oxygen-containing gas supply system for supplying a second oxygen-containing gas having a stronger oxidizing power than the first oxygen-containing gas into the processing chamber. Performing an exhaust system for exhausting the atmosphere in the processing chamber, a process for supplying the metal-containing gas into the processing chamber, and a process for supplying the first oxygen-containing gas into the processing chamber, A first metal oxide layer is formed immediately above, a process of supplying the metal-containing gas into the processing chamber, and a process of supplying the second oxygen-containing gas into the processing chamber are performed, and the first Forming a second metal oxide layer on the metal oxide layer; A control unit for controlling the metal-containing gas supply system, the first oxygen-containing gas supply system, the second oxygen-containing gas supply system, and an exhaust system so as to form a metal oxide film, and The control unit is a substrate processing apparatus that continuously performs the process of forming the first metal oxide layer and the process of forming the second metal oxide layer in the same processing chamber.

  According to the present invention, when forming a metal oxide film using an oxygen-containing gas having strong oxidizing power, it is possible to suppress oxidation of the underlying electrode.

1 is a schematic configuration diagram of a substrate processing apparatus according to a first embodiment of the present invention. It is a longitudinal section showing a schematic structure of a processing furnace concerning a 1st embodiment of the present invention. It is a schematic block diagram of the processing furnace which concerns on the 1st Embodiment of this invention, and is a cross-sectional view in the AA line shown in FIG. It is a figure which shows the outline of the crystal structure of a HfO film | membrane, (A) has shown the monoclinic crystal structure, (B) has shown the tetragonal crystal structure, respectively. It is a schematic diagram shown about the relationship between a crystal structure and a dielectric constant. 1 is a schematic diagram of a capacitor structure of a DRAM according to a first embodiment of the present invention. It is a flowchart of the manufacturing process of the capacitor structure of DRAM which concerns on the 1st Embodiment of this invention. It is a flowchart which shows the formation process of the capacitor insulating film which concerns on the 1st Embodiment of this invention. FIG. 3 is a timing chart relating to gas supply in the capacitor insulating film forming step according to the first embodiment of the present invention. It is a schematic diagram of the capacitor structure of the DRAM according to the second embodiment of the present invention. It is a flowchart which shows the formation process of the capacitor insulating film which concerns on the 2nd Embodiment of this invention. It is a flowchart which shows the formation process of the capacitor insulating film which concerns on the 2nd Embodiment of this invention. FIG. 6 is a timing chart relating to gas supply in a capacitor insulating film forming process according to a second embodiment of the present invention. Is a graph showing the H 2 _O gas and the O ₃ gas HfO film formed using, and H _{2 O} film properties HfO film was formed using only gas. It is a graph showing the H ₂ O gas and _{O 3} HfAlO film formed by using a gas, and _{O 3} film properties HfAlO film formed by using only gas.

<First Embodiment of the Present Invention>
(1) Configuration of Substrate Processing Apparatus First, a configuration example of a substrate processing apparatus 101 according to the first embodiment of the present invention will be described with reference to FIG.

  FIG. 1 is a schematic configuration diagram of a substrate processing apparatus 101 according to the present embodiment. As shown in FIG. 1, the substrate processing apparatus 101 according to this embodiment includes a housing 111. In order to transport the wafer 200 as a substrate made of Si (silicon) or the like into or out of the casing 111, a cassette 110 as a wafer carrier (substrate storage container) that stores a plurality of wafers 200 is used. A cassette stage (substrate storage container delivery table) 114 is provided in front of the housing 111 (on the right side in the drawing). The cassette 110 is placed on the cassette stage 114 by an in-process transfer device (not shown), and is carried out of the casing 111 from the cassette stage 114.

  The cassette 110 is placed on the cassette stage 114 so that the wafer 200 in the cassette 110 is in a vertical posture and the wafer loading / unloading port of the cassette 110 faces upward by the in-process transfer device. The cassette stage 114 rotates the cassette 110 90 degrees in the vertical direction toward the rear of the casing 111 to bring the wafer 200 in the cassette 110 into a horizontal posture, and the wafer loading / unloading port of the cassette 110 is positioned in the rear of the casing 111. It is configured to be able to face.

  A cassette shelf (substrate storage container mounting shelf) 105 is installed at a substantially central portion in the front-rear direction in the housing 111. The cassette shelf 105 is configured to store a plurality of cassettes 110 in a plurality of rows and a plurality of rows. The cassette shelf 105 is provided with a transfer shelf 123 in which a cassette 110 to be transferred by a wafer transfer mechanism 125 described later is stored. Further, a preliminary cassette shelf 107 is provided above the cassette stage 114, and is configured to store the cassette 110 in a preliminary manner.

  A cassette transfer device (substrate container transfer device) 118 is provided between the cassette stage 114 and the cassette shelf 105. The cassette transport device 118 includes a cassette elevator (substrate storage container lifting mechanism) 118a that can be moved up and down while holding the cassette 110, and a cassette transport mechanism (substrate storage container transport mechanism) as a transport mechanism that can move horizontally while holding the cassette 110. 118b. The cassette 110 is transported between the cassette stage 114, the cassette shelf 105, the spare cassette shelf 107, and the transfer shelf 123 by the cooperative operation of the cassette elevator 118a and the cassette transport mechanism 118b.

  A wafer transfer mechanism (substrate transfer mechanism) 125 is provided behind the cassette shelf 105. The wafer transfer mechanism 125 includes a wafer transfer device (substrate transfer device) 125a that can rotate or linearly move the wafer 200 in the horizontal direction, and a wafer transfer device elevator (substrate transfer device) that moves the wafer transfer device 125a up and down. Elevating mechanism) 125b. The wafer transfer device 125a includes a tweezer (substrate transfer jig) 125c that holds the wafer 200 in a horizontal posture. The wafer 200 is picked up from the cassette 110 on the transfer shelf 123 by the cooperative operation of the wafer transfer device 125a and the wafer transfer device elevator 125b, and loaded into a boat (substrate holder) 217 described later (wafer charge). The wafer 200 is removed from the boat 217 (wafer discharge) and stored in the cassette 110 on the transfer shelf 123.

  A processing furnace 202 is provided above the rear portion of the casing 111. An opening (furnace port) is provided at the lower end of the processing furnace 202, and the opening is opened and closed by a furnace port shutter (furnace port opening / closing mechanism) 147. The configuration of the processing furnace 202 will be described later.

  Below the processing furnace 202, a boat elevator (substrate holder lifting mechanism) 115 is provided as a lifting mechanism that lifts and lowers the boat 217 and transports the boat 217 into and out of the processing furnace 202. The elevator 128 of the boat elevator 115 is provided with an arm 128 as a connecting tool. On the arm 128, a disc-shaped seal cap 219 as a lid that supports the boat 217 vertically and hermetically closes the lower end of the processing furnace 202 when the boat 217 is raised by the boat elevator 115 is in a horizontal posture. Is provided.

  The boat 217 includes a plurality of holding members, and a plurality of (for example, about 50 to 150) wafers 200 are aligned in the vertical direction in a horizontal posture and in a state where the centers thereof are aligned in multiple stages. Configured to hold. The detailed configuration of the boat 217 will be described later.

  Above the cassette shelf 105, a clean unit 134a having a supply fan and a dustproof filter is provided. The clean unit 134a is configured to circulate clean air, which is a cleaned atmosphere, inside the casing 111.

  Further, a clean unit (not shown) provided with a supply fan and a dustproof filter so as to supply clean air to the left end portion of the casing 111 opposite to the wafer transfer device elevator 125b and the boat elevator 115 side. Is installed. Clean air blown out from the clean unit (not shown) is configured to be sucked into an exhaust device (not shown) and exhausted to the outside of the casing 111 after circulating around the wafer transfer device 125a and the boat 217. ing.

(2) Operation of Substrate Processing Apparatus Next, the operation of the substrate processing apparatus 101 according to the present embodiment will be described.

  First, the cassette 110 is placed on the cassette stage 114 by an in-process transfer device (not shown) so that the wafer 200 is in a vertical posture and the wafer loading / unloading port of the cassette 110 faces upward. Thereafter, the cassette 110 is rotated 90 ° in the vertical direction toward the rear of the casing 111 by the cassette stage 114. As a result, the wafer 200 in the cassette 110 assumes a horizontal posture, and the wafer loading / unloading port of the cassette 110 faces rearward in the housing 111.

  The cassette 110 is automatically transported to the designated shelf position of the cassette shelf 105 or the spare cassette shelf 107 by the cassette transporting device 118, delivered, temporarily stored, and then stored in the cassette shelf 105 or the spare cassette shelf. The sample is transferred from 107 to the transfer shelf 123 or directly transferred to the transfer shelf 123.

  When the cassette 110 is transferred to the transfer shelf 123, the wafer 200 is picked up from the cassette 110 through the wafer loading / unloading port by the tweezer 125c of the wafer transfer device 125a, and the wafer transfer device 125a and the wafer transfer device elevator 125b are picked up. Are loaded (wafer charged) into the boat 217 behind the transfer shelf 123. The wafer transfer mechanism 125 that has transferred the wafer 200 to the boat 217 returns to the cassette 110 and loads the next wafer 200 into the boat 217.

When a predetermined number of wafers 200 are loaded into the boat 217, the lower end of the processing furnace 202 closed by the furnace port shutter 147 is opened. Subsequently, as the seal cap 219 is raised by the boat elevator 115, the boat 217 holding the wafers 200 is loaded into the processing furnace 202 (boat loading). After boat loading, arbitrary processing is performed on the wafer 200 in the processing furnace 202. Such processing will be described later. After the processing, the wafer 200 and the cassette 110 are stored in the casing 11 in a procedure reverse to the above procedure.
1 is paid out.

(3) Configuration of Processing Furnace Next, the configuration of the processing furnace 202 according to the present embodiment will be described with reference to FIGS. FIG. 2 is a longitudinal sectional view showing a schematic configuration of the processing furnace 202 according to the present embodiment. FIG. 3 is a diagram showing a schematic configuration of the processing furnace 202 according to the present embodiment, and is a cross-sectional view taken along the line AA shown in FIG.

(Processing room)
The processing furnace 202 according to the present embodiment includes a reaction tube 203 that configures an internal space of a processing chamber 201 that accommodates a plurality of wafers 200 stacked in a horizontal posture, and a manifold 209. The reaction tube 203 is made of a nonmetallic material having heat resistance such as SiO ₂ (quartz) or SiC (silicon carbide). The reaction tube 203 is configured such that the upper end is closed and the lower end is opened. The manifold 209 is made of, for example, a metal material such as SUS, and has a cylindrical shape with an open upper end and a lower end. The reaction tube 203 is supported vertically from the lower end side by the manifold 209. The reaction tube 203 and the manifold 209 are arranged concentrically with each other. The lower end (furnace port) of the manifold 209 is configured to be hermetically sealed by a seal cap 219 when the above-described boat elevator 115 is raised. Between the lower end of the manifold 209 and the seal cap 219, an O-ring 220 is provided as a sealing member that hermetically seals the inside of the processing chamber 201.

  A boat 217 as a substrate holder is inserted into the reaction tube 203 (inside the processing chamber 201) from below. The inner diameters of the reaction tube 203 and the manifold 209 are configured to be larger than the maximum outer diameter of the boat 217 loaded with the wafers 200.

  A boat 217 as a substrate holder is made of a heat-resistant material such as quartz or silicon carbide, and is configured to support a plurality of wafers 200 in a horizontal posture and aligned in a state where the centers are aligned with each other in multiple stages. ing. A heat insulating member 218 made of a heat resistant material such as quartz or silicon carbide is provided at the lower part of the boat 217 so that heat from a heater 207 described later is not easily transmitted to the seal cap 219 side. Yes. The heat insulating member 218 may be constituted by a plurality of heat insulating plates made of a heat resistant material such as quartz or silicon carbide, and a heat insulating plate holder that supports them in a horizontal posture in multiple stages. The rotation shaft 255 is provided so as to penetrate the center portion of the seal cap 219 while maintaining airtightness in the processing chamber 201. A rotation mechanism 267 that rotates the rotation shaft 255 is provided below the seal cap 219. By rotating the rotation shaft 255 by the rotation mechanism 267, the boat 217 on which a plurality of wafers 200 are mounted can be rotated while maintaining the airtightness in the processing chamber 201.

  A heater 207 as a heating unit is provided on the outer periphery of the reaction tube 203 concentrically with the reaction tube 203. The heater 207 has a cylindrical shape and is vertically installed by being supported by a heater base 210 as a holding plate. In the processing chamber 201, a temperature sensor 263 is installed as a temperature detector. The heater 207 is configured to adjust the energization state based on temperature information detected by the temperature sensor 263. Thereby, the inside of the processing chamber 201 is configured to be heated to a desired temperature distribution.

(nozzle)
The manifold 209 is provided with gas supply nozzles 233, 234 and 235. The gas supply nozzles 233, 234, and 235 are each configured in an L shape having a vertical portion and a horizontal portion. As shown in FIG. 3, the gas supply nozzles 233, 234, and 235 are respectively disposed along the circumferential direction of the processing chamber 201.

  The vertical portions of the gas supply nozzles 233, 234, and 235 are each configured to extend to the upper portion of the processing chamber 201 so that the downstream end reaches the vicinity of the upper end of the boat 217. A plurality of gas outlets 233a, 234a, and 235a are provided on the side surfaces of the vertical portions of the gas supply nozzles 233, 234, and 235, respectively. The gas outlets 233a, 234a, and 235a are provided at positions (height positions) corresponding to the respective wafers 200 along the stacking direction (vertical direction) of the wafers 200. Further, the opening diameters of the gas outlets 233a, 234a, 235a can be appropriately adjusted so as to optimize the flow rate distribution and velocity distribution of the reaction gas in the processing chamber 201, and may be the same from the lower part to the upper part. You may enlarge gradually from lower part to upper part. The horizontal portions of the gas supply nozzles 233, 234, and 235 are provided so as to penetrate the side wall of the manifold 209.

(Metal-containing gas supply system)
At the upstream end of the gas supply nozzle 233 protruding from the side wall of the manifold 209, a first metal-containing gas supply pipe 240a that supplies TMA (Tri-Methyl-aluminum: Al (CH ₃ ) ₃ ) gas as a metal-containing gas is provided. The downstream end is connected. Connected to the upstream end of the first metal-containing gas supply pipe 240a is a liquid source tank 260 that stores liquid TMA that is a source of TMA gas as a metal-containing gas, for example. Specifically, the upstream end of the first metal-containing gas supply pipe 240a is disposed in the liquid source tank 260 and above the liquid surface of the liquid TMA. The first metal-containing gas supply pipe 240a is provided with a valve 250a. A heater 281 is provided in the first metal-containing gas supply pipe 240a. The heater 281 is configured to heat the inside of the first metal-containing gas supply pipe 240a to, for example, 50 ° C. or more and 60 ° C. or less so that the vaporized TMA gas is not re-liquefied in the first metal-containing gas supply pipe 240a. ing.

  A downstream end of a first carrier gas supply pipe 239 a that supplies a carrier gas such as an inert gas into the liquid source tank 260 is connected to the upstream side of the liquid source tank 260. Specifically, the downstream end of the first carrier gas supply pipe 239a is immersed in the liquid TMA in the liquid source tank 260. The first carrier gas supply pipe 239a is provided with a carrier gas supply source (not shown) for supplying an inert gas, a mass flow controller 241a, and a valve 252a in order from the upstream side.

  By opening the valve 252a, the carrier gas is supplied into the liquid TMA in the liquid source tank 260 while the flow rate is adjusted by the mass flow controller 241a, and the liquid TMA is bubbled. By bubbling the liquid TMA, TMA gas is generated in the liquid raw material tank 260. Note that the flow rate of the carrier gas supplied into the liquid source tank 260 is controlled by the mass flow controller 241a, whereby the amount of TMA gas generated in the liquid source tank 260 is controlled. Then, by opening the valve 250a, the TMA gas as the metal-containing gas generated in the liquid source tank 260 is supplied into the processing chamber 201 through the first metal-containing gas supply pipe 240a and the gas supply nozzle 233. It is configured as follows.

  Mainly, a first carrier gas supply pipe 239a, a carrier gas supply source (not shown), a mass flow controller 241a, a valve 252a, a liquid raw material tank 260, a first metal-containing gas supply pipe 240a, a valve 250a, a heater 281, a gas supply nozzle 233, A TMA gas supply system is configured by the gas outlet 233a.

At the upstream end of the gas supply nozzle 234 protruding from the side wall of the manifold 209, downstream of the second metal-containing gas supply pipe 240 d for supplying TEMAH (tetrakisethylmethylaminohafnium, Hf (NEtMe) ₄ ) gas as a metal-containing gas. The ends are connected. Second
Connected to the upstream end of the metal-containing gas supply pipe 240d is a liquid source tank 261 for storing liquid TEMAH as a source of TEMAH gas as a metal-containing gas, for example. Specifically, the upstream end of the second metal-containing gas supply pipe 240d is disposed in the liquid source tank 261 and above the liquid level of the liquid TEMAH. A valve 250d is provided in the second metal-containing gas supply pipe 240d. A heater 282 is provided in the second metal-containing gas supply pipe 240d. The heater 282 is configured to heat the inside of the second metal-containing gas supply pipe 240d to, for example, about 130 ° C. so that the vaporized TEMAH gas is not re-liquefied in the second metal-containing gas supply pipe 240d.

  Connected to the upstream side of the liquid source tank 261 is a downstream end of a second carrier gas supply pipe 239 d that supplies a carrier gas such as an inert gas into the liquid source tank 261. Specifically, the downstream end of the second carrier gas supply pipe 239d is immersed in the liquid TEMAH in the liquid source tank 261. The second carrier gas supply pipe 239d is provided with a carrier gas supply source (not shown) for supplying an inert gas, a mass flow controller 241d, and a valve 252d in order from the upstream side.

  By opening the valve 252d, the carrier gas is supplied into the liquid TEMAH in the liquid source tank 261 while the flow rate is adjusted by the mass flow controller 241d, and the liquid TEMAH is bubbled. In this way, TEMAH gas is generated in the liquid source tank 261. Note that the flow rate of the carrier gas supplied into the liquid source tank 261 is controlled by the mass flow controller 241d, whereby the amount of TEMAH gas generated in the liquid source tank 261 is controlled. Then, by opening the valve 250d, the TEMAH gas as the metal-containing gas generated in the liquid raw material tank 261 is supplied into the processing chamber 201 through the second metal-containing gas supply pipe 240d and the gas supply nozzle 234. It is configured as follows.

  Mainly, a second carrier gas supply pipe 239d, a carrier gas supply source (not shown), a mass flow controller 241d, a valve 252d, a liquid source tank 261, a second metal-containing gas supply pipe 240d, a valve 250d, a heater 282, a gas supply nozzle 234, A TEMAH gas supply system is configured by the gas outlet 234a.

  A metal-containing gas supply system that supplies at least one type (here, two types) of metal-containing gas into the processing chamber 201 is mainly configured by the TMA gas supply system and the TEMAH gas supply system.

(First oxygen-containing gas supply system)
The downstream end of the first oxygen-containing gas supply pipe 240b is connected to the upstream end of the gas supply nozzle 235 protruding from the side wall of the manifold 209. The upstream end of the first oxygen-containing gas supply pipe 240b, the first oxygen-containing gas the H _{2 O} gas supply source for supplying the H _{2 O} gas as a (oxidizing agent) (water vapor) (not shown) is connected ing. In the first oxygen-containing gas supply pipe 240b, a mass flow controller 241b and a valve 250b are provided in this order from the upstream side. By opening the valve 250b, the H ₂ O gas is supplied into the processing chamber 201 through the first oxygen-containing gas supply pipe 240b and the gas supply nozzle 235. Note that the supply flow rate of the H ₂ O gas into the processing chamber 201 can be controlled by the mass flow controller 241b.

The first oxygen-containing gas is supplied into the processing chamber 201 mainly by the first oxygen-containing gas supply pipe 240b, the H ₂ O gas supply source (not shown), the mass flow controller 241b, the valve 250b, the gas supply nozzle 235, and the gas outlet 235a. An H ₂ O gas supply system is configured as a first oxygen-containing gas supply system for supplying oxygen.

(Second oxygen-containing gas supply system)
The downstream end of the second oxygen-containing gas supply pipe 240c is connected to the downstream side of the valve 250b provided in the first oxygen-containing gas supply pipe 240b. The upstream end of the second oxygen-containing gas supply pipe 240c, O _{3 (ozone)} for supplying gas O ₃ gas supply source of a second oxygen-containing gas (oxidizer) (not shown) is connected . The second oxygen-containing gas supply pipe 240c is provided with a mass flow controller 241c and a valve 250c in order from the upstream side. By opening the valve 250c, the O ₃ gas is supplied into the processing chamber 201 through the second oxygen-containing gas supply pipe 240c. Note that the supply flow rate of the O ₃ gas into the processing chamber 201 is configured to be controllable by the mass flow controller 241c.

A first oxygen-containing gas supply pipe 240c, an O ₃ gas supply source (not shown), a mass flow controller 241c, a valve 250c, a first oxygen-containing gas supply pipe 240b, and a gas supply nozzle 235 are mainly used in the processing chamber 201. An O ₃ gas supply system is configured as a second oxygen-containing gas supply system that supplies a second oxygen-containing gas having a stronger oxidizing power than the oxygen-containing gas.

(Inert gas supply system)
The downstream end of the inert gas supply pipe 240p is connected to the downstream side of the valve 250a provided in the first metal-containing gas supply pipe 240a. The inert gas supply pipe 240p is provided with an inert gas supply source (not shown) for supplying an inert gas such as N ₂ gas, a mass flow controller (not shown), and a valve 250p in order from the upstream side. Similarly, the downstream end of the inert gas supply pipe 240s is connected to the downstream side of the valve 250d provided in the second metal-containing gas supply pipe 240d. The inert gas supply pipe 240s is provided with an inert gas supply source (not shown), a mass flow controller (not shown), and a valve 250s that supply an inert gas such as N ₂ gas in order from the upstream side. Similarly, the downstream end of the inert gas supply pipe 240q is connected to the downstream side of the valve 250b provided in the first oxygen-containing gas supply pipe 240b and to the upstream side of the second oxygen-containing gas supply pipe 240c. ing. The inert gas supply pipe 240q is provided with an inert gas supply source (not shown), a mass flow controller (not shown), and a valve 250q that supply an inert gas such as N ₂ gas in order from the upstream side.

The inert gas supplied from the inert gas supply pipes 240p, 240q, and 240s functions as a purge gas for purging the inside of the processing chamber 201, TMA gas and TEMAH gas as the metal-containing gas, and the first oxygen-containing gas. It functions as a diluent gas for diluting H ₂ O gas, O ₃ gas as the second oxygen-containing gas, and the like. Further, the inert gas supplied from the inert gas supply pipes 240p, 240q, and 240s has a function of suppressing the residual gas or the like in the processing chamber 201 from flowing to the upstream side of the gas supply nozzles 233, 234, and 235. .

  Mainly, inert gas supply pipes 240p, 240q, 240s, an inert gas supply source (not shown), a mass flow controller (not shown), valves 250p, 250q, 250s, a first metal-containing gas supply pipe 240a, and a second metal-containing gas supply pipe An inert gas supply system is configured by 240d, the first oxygen-containing gas supply pipe 240b, the second oxygen-containing gas supply pipe 240c, and the gas supply nozzles 233, 234, and 235.

(Exhaust system)
The upstream end of the exhaust pipe 231 is connected to the side wall of the manifold 209. The exhaust pipe 231 includes, in order from the upstream side, a pressure sensor 245 as a pressure detector (pressure detector) that detects pressure, an APC (Auto Pressure Controller) valve 251 as a pressure regulator, and a vacuum pump as a vacuum exhaust device. 246 is provided. The APC valve 251 is an on-off valve that can be evacuated and stopped by opening and closing the valve and that can further adjust the opening of the valve. The inside of the processing chamber 201 can be set to a desired pressure by adjusting the opening degree of the opening / closing valve of the APC valve 251 based on pressure information from the pressure sensor 245 while operating the vacuum pump 246. Has been.

  An exhaust system that exhausts the atmosphere in the processing chamber 201 is mainly configured by the exhaust pipe 231, the pressure sensor 245, the APC valve 251, and the vacuum pump 246.

(controller)
The controller 280 as a control unit includes mass flow controllers 241a, 241b, 241c, 241d, valves 250a, 250b, 250c, 250d, 250p, 250q, 250s, 252a, 252d, a temperature sensor 263, a heater 207, a pressure sensor 245, and an APC valve. 251, a vacuum pump 246, a rotation mechanism 267, a boat elevator 115, and the like. The controller 280 adjusts the flow rate of the mass flow controllers 241a, 241b, 241c, 241d, opens / closes the valves 250a, 250b, 250c, 250d, 250p, 250q, 250s, 252a, 252d, adjusts the pressure of the APC valve 251, and the heater 207. The temperature adjustment operation, the start / stop of the vacuum pump 246, the rotation speed adjustment of the rotation mechanism 267, the control of the lifting operation of the boat elevator 115, and the like are performed.

(4) Manufacturing Process of DRAM Capacitor Structure Next, a manufacturing process of the DRAM capacitor structure on the wafer 200 will be described with reference to FIGS. 6 and 7 as one process of the manufacturing process of the semiconductor device according to the present embodiment. . FIG. 6 is a schematic diagram of the capacitor structure of the DRAM according to the present embodiment. FIG. 7 is a flowchart of the manufacturing process of the DRAM capacitor structure according to this embodiment.

  In order to form a DRAM capacitor structure, first, a TiN film (titanium nitride film) 610 that is a metal film is formed as a lower electrode on a wafer 200 as a substrate (lower electrode forming step). Then, a HfO film (hafnium nitride film) 600 that is a metal oxide film is formed as a capacitor insulating film on the formed TiN film 610 (metal oxide film forming step). In the present embodiment, the HfO film 600 is formed by laminating the first HfO layer 510 and the second HfO layer 560. Details thereof will be described later.

  Then, in order to control the crystal structure of the HfO film 600 or to make the HfO film 600 dense, the HfO film 600 is annealed (annealing process). Then, a TiN film 620 which is a metal film is formed as an upper electrode on the annealed HfO film 600 (upper electrode forming process), and the manufacturing process of the capacitor structure is completed.

(5) Capacitor Insulating Film Forming Step Next, a metal oxide film forming step as the above capacitor insulating film will be described.

  The capacitor insulating film can be formed by, for example, a CVD method or an ALD method. The CVD method is a method of forming a film by simultaneously supplying a plurality of types of gases (metal-containing gas and oxygen-containing gas) containing a plurality of elements constituting the film into a processing chamber. The ALD method is a method of forming a film by alternately supplying a plurality of types of gases (metal-containing gas and oxygen-containing gas) including a plurality of elements constituting the film. By controlling processing conditions such as supply flow rate, supply time, and plasma power during gas supply, the film thickness and film characteristics of the silicon oxide film (SiO film) and silicon nitride film (SiN film) formed on the wafer can be controlled. Can be controlled.

In the above-described CVD method or ALD method, for example, when an SiO film is formed, an SiN film is formed so that the composition ratio of the film becomes a stoichiometric composition of O / Si≈2. In this case, the gas supply conditions are generally controlled so that the composition ratio of the film is N / Si≈1.33 which is the stoichiometric composition. On the other hand, it is also possible to control the gas supply conditions so that the composition ratio of the film to be formed becomes a predetermined composition ratio different from the stoichiometric composition. That is, the gas supply conditions may be controlled so that at least one element among the plurality of elements constituting the film is excessive with respect to the stoichiometric composition than the other elements. In this manner, film formation can be performed while controlling the ratio of a plurality of elements constituting the film, that is, the composition ratio of the film.

However, when a capacitor insulating film is formed by CVD or ALD, if an O ₃ gas having a strong oxidizing power is used as the oxygen-containing gas, even the underlying electrode (lower electrode 610 in FIG. 6) is oxidized. There was a case. In addition, when an oxygen-containing gas having a weak oxidizing power is used, the metal oxide film is not sufficiently oxidized, and the dielectric constant of the capacitor insulating film may be lowered. Therefore, in the embodiment, when the capacitor insulating film is formed, the type of the oxygen-containing gas is switched during the film formation to solve these problems. That is, a gas having a relatively weak oxidizing power (first oxygen-containing gas) is used at the start of formation, and when the metal oxide film reaches a predetermined thickness, the gas is switched to a gas having a strong oxidizing power (second oxygen-containing gas). Therefore, it was decided to solve the above-mentioned problem.

  Hereinafter, a capacitor insulating film forming process according to the present embodiment to which the above-described knowledge is applied will be described with reference to FIGS. FIG. 8 is a flowchart showing in detail a capacitor insulating film forming process according to the present embodiment, and FIG. 9 is a timing chart relating to gas supply in the capacitor insulating film forming process according to the present embodiment. In this step, an HfO film having a stoichiometric composition is formed by an ALD method as a capacitor insulating film using the above-described substrate processing apparatus. In the following description, the configuration of each part constituting the substrate processing apparatus is controlled by the controller 280.

(Substrate carrying-in process S110)
First, a plurality of wafers 200 on which TiN films 610 as lower electrodes are formed in advance are loaded into the boat 217 (wafer charge). Then, the boat 217 holding the plurality of wafers 200 is lifted by the boat elevator 115 and accommodated in the processing chamber 201 (boat loading). In this state, the seal cap 219 is in a state of hermetically sealing the lower end of the manifold 209 via the O-ring 220. During wafer charging and boat loading, for example, it is preferable to open the valves 250p, 250q, and 250s and continue to supply an inert gas as a purge gas into the processing chamber 201.

(Depressurization / heating step S120)
Subsequently, the valves 250p, 250q, and 250s are closed, and the inside of the processing chamber 201 is evacuated by the vacuum pump 246 so that a desired processing pressure (degree of vacuum) is obtained. At this time, the opening degree of the APC valve 251 is feedback controlled based on the pressure information measured by the pressure sensor 245. In addition, the power supply to the heater 207 is feedback controlled based on the temperature information detected by the temperature sensor 263 so that the surface of the wafer 200 reaches a desired processing temperature. Then, the rotation mechanism 267 starts rotation of the boat 217 and the wafer 200. The temperature adjustment, the pressure adjustment, and the rotation of the wafer 200 are continued until the HfO film forming step S30 described later is completed.

(HfO film forming step S130)
Next, an HfO film forming step S130 for forming an HfO film (hafnium oxide film) 600 which is a metal oxide film as a capacitor insulating film is performed.

In the HfO film forming step S130, the first step (S131a to S131e) and the second step (S132a to S132e) are sequentially performed, so that the first metal oxide layer as the first metal oxide layer is formed directly on the TiN film 610. An HfO film 600 is formed by laminating one HfO layer 510 and a second HfO layer 560 as a second metal oxide layer.

In the first step, the TEMAH gas as the metal-containing gas and the H ₂ O gas as the first oxygen-containing gas are alternately supplied into the processing chamber 201 so as not to mix with each other, and the TiN film 610 is supplied. A first HfO layer 510 is formed immediately above the substrate. In the second step, the TEMAH gas as the metal-containing gas and the O ₃ gas as the second oxygen-containing gas having a stronger oxidizing power than the first oxygen-containing gas are alternately processed so as not to mix with each other. A second HfO layer 560 is formed on the first HfO layer 510 by supplying the inside of the chamber 201.

  First, the first step (S131a to S131e) will be described.

(TEMAH gas supply process S131a)
The valve 252d of the second carrier gas supply pipe 239d is opened, and an inert gas (for example, N ₂₎ as a carrier gas from the carrier gas supply source (not shown) into the liquid source tank 261 while controlling the flow rate by the mass flow controller 241d. Gas) supply. The flow rate of the inert gas is, for example, 5 slm. Then, liquid TEMAH is bubbled with an inert gas, and generation of TEMAH gas as a metal-containing gas in liquid source tank 261 is started. It should be noted that the generation of TEMAH gas is performed in parallel with the depressurization / temperature increase step S120, and it is preferable to stabilize the amount of TEMAH gas generated at the completion of the depressurization / temperature increase step S120 (preliminary vaporization).

  In a state where the production amount of the TEMAH gas is stable, the valve 250d of the second metal-containing gas supply pipe 240d is opened, and supply of the TEMAH gas into the processing chamber 201 via the gas supply nozzle 234 is started. The TEMAH gas supplied into the processing chamber 201 flows between the wafers 200 in parallel, and is then exhausted from the exhaust pipe 231. At this time, the opening degree of the APC valve 251 is adjusted to maintain the pressure in the processing chamber 201 within a range of 30 Pa to 500 Pa, for example, 100 Pa. When the predetermined time has elapsed, the valve 250d is closed, and the supply of TEMAH gas into the processing chamber 201 is stopped. The supply time of the TEMAH gas is, for example, in the range of 1 second to 120 seconds. During the supply of TEMAH gas, in order to promote the supply of TEMAH molecules to the surface of the TiN film 610, the APC valve 251 is closed to stop the exhaust, and the surface of the TiN film 610 is kept in a high-pressure atmosphere for a predetermined time (for example, 4 seconds or less). You may be exposed to.

At this time, the gas present in the processing chamber 201 is only an inert gas such as TEMAH gas and bubbling N ₂ gas, and there is no oxygen-containing gas such as H ₂ O gas or O ₃ gas. Therefore, the TEMAH gas causes a chemical adsorption (surface reaction) on the surface of the TiN film 610 without causing a gas phase reaction in the processing chamber 201, and an adsorption layer of TEMAH molecules having a thickness of less than one atomic layer to several atomic layers. Alternatively, an Hf layer is formed. The TEMAH molecule adsorption layer includes a continuous adsorption layer of TEMAH molecules and a discontinuous adsorption layer. The Hf layer includes a continuous layer composed of Hf and an Hf thin film formed by overlapping these layers. In the following, all of these are also referred to as Hf-containing layers.

  While supplying the TEMAH gas, the valves 250p and 250q are opened to supply the inert gas into the inert gas supply pipes 240p and 240q and the gas supply nozzles 233 and 235. Thereby, it can suppress that TEMAH gas etc. wrap around in the gas supply nozzles 233 and 235.

(Exhaust process S131b)
After closing the valve 250d and stopping the supply of the TEMAH gas into the processing chamber 201, the opening of the APC valve 251 is increased to exhaust the atmosphere in the processing chamber 201, and the processing chamber 20
The TEMAH gas and reaction products remaining in 1 are removed. At this time, the valves 250p, 250q, and 250s are opened, and the inside of the processing chamber 201 is purged by supplying an inert gas into the processing chamber 201. Thereby, the residual gas can be efficiently removed from the processing chamber 201. After a predetermined time elapses, the valves 250p, 250q, 250s are closed to stop supplying the inert gas. By carrying out the evacuation step S102, as a TEMAH gas supplied by TEMAH gas supply step S131, not mixed with one another and the _{H 2} O gas is supplied with _{H 2} O gas supply step S133 described later.

(H ₂ O gas supply step S131c)
Subsequently, H ₂ O gas as a first oxygen-containing gas is supplied into the processing chamber 201 to oxidize the Hf-containing layer formed immediately above the TiN film 610 to form an HfO layer. More specifically, the valve 250b of the first oxygen-containing gas supply pipe 240b is opened, and the processing chamber 201 from the H ₂ O gas supply source (not shown) through the gas supply nozzle 235 while controlling the flow rate by the mass flow controller 241b. The supply of H ₂ O gas into the inside is started. The H ₂ O gas supplied into the processing chamber 201 flows in parallel between the wafers 200 and is then exhausted from the exhaust pipe 231. At this time, the opening degree of the APC valve 251 is adjusted to maintain the pressure in the processing chamber 201 within a range of 10 Pa to 100 Pa, for example, 60 Pa. The supply amount of H ₂ O gas is, for example, a concentration of 200 g / m ³ and a flow rate of 0.1 g / min. When the predetermined time has elapsed, the valve 250b is closed, and the supply of H ₂ O gas into the processing chamber 201 is stopped. The supply time of the H ₂ O gas is set, for example, in the range of 10 seconds to 60 seconds.

The H ₂ O gas supplied to each laminated wafer 200 comes into contact with the Hf-containing layer on the TiN film 610 to oxidize it, and has a thickness of less than one atomic layer to several atomic layers on the TiN film 610. An HfO layer is formed. Note that the H ₂ O gas in contact with the TiN film 610 has a relatively weak oxidizing power, so that the oxidation of the underlying TiN film 610 can be suppressed.

While supplying the H ₂ O gas, the valves 250p and 250s are opened, and the inert gas is supplied into the inert gas supply pipes 240p and 240s and the gas supply nozzles 233 and 234. Thereby, it is possible to suppress the H ₂ O gas and the like from entering the gas supply nozzles 233 and 234.

(Exhaust process S131d)
After the valve 250b is closed and the supply of H ₂ O gas into the processing chamber 201 is stopped, the opening of the APC valve 251 is increased to exhaust the atmosphere in the processing chamber 201, and into the processing chamber 201 Residual H ₂ O gas and reaction products are excluded. At this time, the valves 250p, 250q, and 250s are opened, and the inside of the processing chamber 201 is purged by supplying an inert gas (for example, N ₂ gas) into the processing chamber 201. Thereby, the residual gas can be efficiently removed from the processing chamber 201. After a predetermined time has elapsed, the valves 250p, 250q, and 250s are closed. By carrying out the evacuation step S134, it and the _{H 2} O gas was fed with _{H 2} O gas supply step S133, so as not to mix with each other and TEMAH gas supplied in TEMAH gas supply step S131 in the next cycle.

(Predetermined number of execution steps S131e)
Thereafter, the TEMAH gas supply step S131a to the exhaust step S131d are set as one cycle, this cycle is performed a predetermined number of times, and an HfO layer having a thickness of less than one atomic layer to several atomic layers formed using H ₂ O gas is sequentially formed. By laminating, a first HfO layer 510 as a first metal oxide layer having a predetermined thickness is formed on the TiN film 610 as a lower electrode (see FIG. 6).

As described above, in the first step (S131a to S131e), H ₂ O gas having a relatively weak oxidizing power is used as the first oxygen-containing gas. Thereby, the underlying TiN film 610
Can be suppressed. However, a metal oxide film formed using H ₂ O gas is less oxidized than a metal oxide film having an equivalent film thickness formed using an oxygen-containing gas such as O ₃ gas having strong oxidizing power. This tends to be sufficient and the leakage current tends to increase. Therefore, it is preferable to adjust so that the film thickness of the first HfO layer 510 does not become too thick. For example, the thickness of the first HfO layer 510 is preferably 4 nm or less.

  If the film thickness of the first HfO layer 510 is too thin, a second oxygen-containing gas used in a second step (S132a to S132e) to be described later is supplied to the TiN film 610 through the first HfO layer 510. As a result, the TiN film 610 may be oxidized, leading to an increase in EOT. That is, in order for the first HfO layer 510 to function as an antioxidant film that suppresses the oxidation of the base (TiN film 610), for example, the thickness of the first HfO layer 510 is preferably set to 1 nm or more.

  Subsequently, the second step (S132a to S132e) will be described.

(TEMAH gas supply step S132a)
The TEMAH gas is supplied into the processing chamber 201 by the same processing procedure and processing conditions as the above-described TEMAH gas supply step S131a, and Hf containing a thickness of less than one atomic layer to several atomic layers is formed on the first HfO layer 510. Form a layer.

(Exhaust process S132b)
Subsequently, the atmosphere in the processing chamber 201 is exhausted by the same processing procedure and processing conditions as the above-described exhausting step S131b, and TEMAH gas, reaction products, and the like remaining in the processing chamber 201 are removed. By carrying out the evacuation step S132b, as a TEMAH gas supplied by TEMAH gas supply step S132a, not mixed with one another and the _{O 3} gas is supplied in the _{O 3} gas supply step S132c below.

(O ₃ gas supply step S132c)
Subsequently, O ₃ gas as a second oxygen-containing gas is supplied into the processing chamber 201 to oxidize the Hf-containing layer formed on the first HfO layer 510 to form an HfO layer. Specifically, the valve 250c of the second oxygen-containing gas supply pipe 240c is opened, and the flow rate is controlled by the mass flow controller 241c, while the inside of the processing chamber 201 passes through the gas supply nozzle 235 from the O ₃ gas supply source (not shown). The supply of O ₃ gas to is started. The O ₃ gas supplied into the processing chamber 201 flows between the wafers 200 in parallel, and is then exhausted from the exhaust pipe 231. At this time, the opening degree of the APC valve 251 is adjusted to maintain the pressure in the processing chamber 201 within a range of 30 Pa to 500 Pa, for example, 130 Pa. The supply amount of the O ₃ gas is, for example, a concentration of 250 g / m ³ and a flow rate of 15 slm. The supply time of the O ₃ gas is, for example, 180 seconds. When the predetermined time has elapsed, the valve 250c is closed and the supply of O ₃ gas into the processing chamber 201 is stopped. The supply time of the O ₃ gas is set, for example, within a range of 30 seconds to 300 seconds.

The O ₃ gas supplied to each stacked wafer 200 contacts and oxidizes the Hf-containing layer on the first HfO layer 510, and less than one atomic layer to several atoms on the first HfO layer 510. An HfO layer having a layer thickness is formed. Since the O ₃ gas has a relatively strong oxidizing power, the Hf-containing layer is more reliably oxidized. As a result, the second HfO layer 560 described later can be sufficiently oxidized to increase the dielectric constant.

In this embodiment, since the first HfO layer 510 is formed in advance, it is possible to prevent the O ₃ gas used in the second step from being directly supplied to the underlying TiN film 610. Thereby, the oxidation of the TiN film 610 can be suppressed. In addition, by setting the film thickness of the first HfO layer 510 to, for example, 1 nm or more, it is possible to more reliably avoid the O ₃ gas being supplied to the TiN film 610, and the oxidation of the TiN film 610 can be more effectively performed. Can be suppressed. Thus, the first HfO layer 510 functions as an antioxidant film.

While supplying the O ₃ gas, the valves 250p and 250s are opened, and the inert gas is supplied into the inert gas supply pipes 240p and 240s and the gas supply nozzles 233 and 234. Thus, it is possible to suppress the _{O 3} gas or the like from flowing into the gas supply nozzle 233 and 234.

(Exhaust process S132d)
Subsequently, the atmosphere in the processing chamber 201 is exhausted by the same processing procedure and processing conditions as in the above-described exhausting step S131d, and O ₃ gas, reaction products, and the like remaining in the processing chamber 201 are removed. By carrying out the evacuation step S132d, _{O 3} and _{O 3} gas supplied by the gas supplying step S132c, so as not to mix the TEMAH gas supplied in TEMAH gas supply step S132a of the next cycle to each other.

(Predetermined number of times execution step S132e)
Thereafter, the TEMAH gas supply step S132a to the exhaust step S132e are set as one cycle, this cycle is performed a predetermined number of times, and an HfO layer having a thickness of less than one atomic layer to several atomic layers formed using O ₃ gas is sequentially laminated. As a result, a second HfO layer 560 as a second metal oxide layer having a desired thickness is formed on the first HfO layer 510. As a result, an HfO film 600 as a metal oxide film in which the first HfO layer 510 and the second HfO layer 560 are laminated is formed on the TiN film 610 (see FIG. 6).

(Atmospheric pressure return step S140)
After the HfO film 600 having a predetermined thickness is formed, the opening degree of the APC valve 231a is reduced, the valves 250p, 250q, and 250s are opened, and the processing chamber 201 is maintained until the pressure in the processing chamber 201 becomes atmospheric pressure. An inert gas such as N ₂ gas is supplied into the inside. Further, the output of the heater 207 is lowered to lower the temperature in the processing chamber 201.

(Substrate unloading step S150)
Then, the boat 217 is unloaded from the processing chamber 201 (boat unloading) and the film-formed wafer 200 is detached from the boat 217 (wafer discharge) in the reverse order of the substrate loading step S110 described above. The step of forming the capacitor insulating film according to the embodiment is completed. At this time, it is preferable that the valves 250p, 250q, and 250s are opened and the purge gas is continuously supplied into the processing chamber 201.

(6) Effects according to the present embodiment According to the present embodiment, the following one or more effects are achieved.

(A) According to the present embodiment, in the first step, H ₂ O gas having relatively weak oxidizing power is used as the first oxygen-containing gas. That is, when forming the first HfO layer 510 as the first metal oxide layer, an oxygen-containing gas having a relatively weak oxidizing power is used. As a result, the oxidation of the TiN film 610 as a base can be suppressed. And it can avoid that a low dielectric constant layer is formed in the surface of the TiN film | membrane 610, the increase in EOT can be prevented, and the performance of a semiconductor device can be improved.

(B) According to the present embodiment, the first HfO layer 510 is formed in advance before performing the second step. As a result, the O ₃ gas used in the second step can be prevented from being directly supplied to the underlying TiN film 610, and oxidation of the TiN film 610 can be suppressed. Thereby, the increase in EOT can be prevented and the performance of the semiconductor device can be improved.

(C) According to this embodiment, by setting the film thickness of the first HfO layer 510 to, for example, 1 nm or more, it is possible to more reliably avoid the O ₃ gas being supplied to the TiN film 610. Thus, the oxidation of the TiN film 610 can be suppressed more effectively. Thereby, increase of EOT can be prevented and the performance of the semiconductor device can be improved.

(D) According to this embodiment, the temperature (film formation temperature) in the processing chamber 201 in the first step and the second step is set to 220 ° C. or lower, for example, 150 ° C. Thereby, it can be avoided that the oxidizing power of the H ₂ O gas and the O ₃ gas becomes excessively strong, and the oxidation of the TiN film 610 as a base can be suppressed. Thereby, the increase in EOT can be prevented and the performance of the semiconductor device can be improved.

(E) According to the present embodiment, in the second step, O ₃ gas having a stronger oxidizing power than H ₂ O gas is used as the second oxygen-containing gas. Thereby, the second HfO layer 560 constituting the upper layer of the HfO film 600 can be more reliably oxidized. Thereby, the dielectric constant of the entire HfO film 600 can be increased, the leakage current can be reduced, and the performance of the semiconductor device can be improved.

(F) According to the present embodiment, the film thickness of the first HfO layer 510 formed using the H ₂ O gas having relatively weak oxidizing power is set to a predetermined thickness or less, for example, 4 nm or less. Thereby, a decrease in the dielectric constant of the entire HfO film 600 can be suppressed, leakage current can be reduced, and the performance of the semiconductor device can be improved.

<Second Embodiment of the Present Invention>
In order to increase the dielectric constant of the HfO film 600, it is effective to make the crystal structure tetragonal. However, when an HfO film is formed, the crystal structure generally becomes monoclinic and the dielectric constant tends to decrease. 4A and 4B are diagrams schematically showing the crystal structure of the HfO film, where FIG. 4A shows a monoclinic crystal structure and FIG. 4B shows a tetragonal crystal structure. The tetragonal system has a smaller molecular volume than the monoclinic system, the internal polarizer density increases (that is, the charge density increases because the surface area decreases), and the dielectric constant increases. FIG. 5 is a schematic diagram showing the relationship between the crystal structure and the dielectric constant.

  In order to make the crystal structure of the HfO film tetragonal, the HfO film may be annealed at a high temperature. Note that the HfO film before annealing needs to be in an amorphous state. This is because the monoclinic system has a stable structure and is difficult to phase transition to the tetragonal system. In the amorphous state, the crystal structure to be grown can be selected relatively easily by controlling the annealing temperature. However, in such a method, it is necessary to perform annealing at a high temperature of about 1670 ° C., for example, and it has been difficult to realize such a temperature in a general heat treatment furnace.

  However, the above-described phase transition temperature can be lowered by adding (doping or laminating) another metal such as Al (aluminum) to the HfO film. That is, when a second element (for example, Al) different from the first element is added (doping or laminating) to the metal oxide layer containing the first element (for example, Hf), the phase transition depends on the composition ratio. The temperature can be lowered.

(1) Capacitor Insulating Film Forming Process A capacitor insulating film forming process to which the above knowledge is applied will be described below with reference to FIGS. FIG. 10 is a schematic diagram of a capacitor structure of the DRAM according to the present embodiment. FIG. 11 and FIG. 12 are flowcharts showing the capacitor insulating film forming process according to this embodiment. FIG. 13 is a timing chart relating to gas supply in the capacitor insulating film forming step according to the present embodiment. This embodiment is also implemented by the above-described substrate processing apparatus. Further, processes other than the capacitor insulating film forming process are the same as those in the above-described embodiment.

(Substrate carrying-in process S210)
A plurality of wafers 200 on which TiN films 610 as lower electrodes are formed in advance are loaded into the boat 217 and accommodated in the processing chamber 201 by the same procedure as the substrate carry-in step S110 of the above-described embodiment.

(Decompression / Temperature raising step S220)
The temperature and pressure in the processing chamber 201 are controlled by the same procedure as the decompression / temperature raising step S120 of the above-described embodiment, and the rotation of the wafer 200 is started.

(HfAlO film forming step S230)
Next, an HfAlO film forming step S230 for forming an HfAlO film 600A (see FIG. 10) that is a metal oxide film as a capacitor insulating film is performed.

  In the HfAlO film formation step S230, the first step (steps S231a to S233) and the second step (steps S234a to S236) are sequentially performed, so that the first metal oxide is directly above the TiN film 610. An HfAlO film 600A in which a first HfAlO layer 530A as a layer and a second HfAlO layer 580A as a second metal oxide layer are stacked is formed.

In the first step, the processing chamber 201 is alternately arranged so that the TEMAH gas as the metal-containing gas, the TMA gas as the metal-containing gas, and the H ₂ O gas as the first oxygen-containing gas are not mixed with each other. The first HfAlO layer 530A is formed immediately above the TiN film 610. Specifically, (1) a process in which TEMAH gas is supplied into the processing chamber 201 and exhausted and a process in which H ₂ O gas is supplied into the processing chamber 201 and exhausted are defined as one cycle. By performing the number of times, a step (S231a to S231e) of forming the lower layer side HfO layer 510A, (2) a step of supplying and exhausting TMA gas into the processing chamber 201, and H ₂ O gas in the processing chamber 201 The process of forming the lower layer side AlO layer 520A (S232a to S232e) by carrying out this cycle a predetermined number of times, with the step of supplying and exhausting the gas to one cycle, and performing this set a predetermined number of times (S233) Thus, the first HfAlO layer 530A is formed.

In the second step, the TEMAH gas as the metal-containing gas, the TMA gas as the metal-containing gas, and the O ₃ gas as the second oxygen-containing gas having a stronger oxidizing power than the first oxygen-containing gas, Are alternately supplied into the processing chamber 201 so as not to be mixed with each other, and a second HfAlO layer 580A is formed on the first HfAlO layer 530A. Specifically, (1) the process of supplying and exhausting TEMAH gas into the processing chamber 201 and the process of supplying and exhausting O ₃ gas into the processing chamber 201 are defined as a predetermined number of cycles. By performing, a step (S234a to S234e) of forming the upper HfO layer 560A on the first HfAlO layer 530A, (2) a step of supplying and exhausting TMA gas into the processing chamber 201, and O ₃ A step of forming the lower layer side AlO layer 570A on the upper layer side HfO layer 560A by carrying out this cycle a predetermined number of times, with the step of supplying and exhausting the gas into the processing chamber 201 (S235a to S235e) Are set a predetermined number of times (S236), thereby forming the second HfAlO layer 580A.

  First, the first step (steps S231a to S233) will be described.

(Formation process of lower layer side HfO layer 510A)
The TMAH gas supply process S231a, the exhaust process S231b, the H ₂ O gas supply process S231c, and the exhaust process S231d are performed as a predetermined number of cycles, whereby the lower layer side HfO layer 510A having a predetermined thickness is formed on the TiN film 610. (See FIG. 10). This process is performed according to the same processing procedure and processing conditions as the first process (S131a to S131e) of the first embodiment.

(Formation process of lower layer side AlO layer 520A)
Subsequently, the following steps S232a to S232e are performed to form a lower-layer side AlO layer 520A having a predetermined thickness on the lower-layer side HfO layer 510A (see FIG. 10).

(TMA gas supply process S232a)
The valve 252a of the first carrier gas supply pipe 239a is opened, and an inert gas (for example, N ₂₎ as a carrier gas from the carrier gas supply source (not shown) into the liquid source tank 261 while controlling the flow rate by the mass flow controller 241a. Gas) supply. The flow rate of the inert gas is 1 slm, for example. Then, liquid TMA is bubbled with an inert gas, and generation of TMA as a metal-containing gas in liquid source tank 261 is started. It should be noted that the generation of TMA gas is performed in parallel with the pressure reduction / temperature increase step S220, and it is preferable to stabilize the amount of TEMAH gas generated when the pressure reduction / temperature increase step S220 is completed (preliminary vaporization).

  In a state where the production amount of TMA gas is stable, the valve 250a of the first metal-containing gas supply pipe 240a is opened, and supply of TMA gas into the processing chamber 201 via the gas supply nozzle 233 is started. The TMA gas supplied into the processing chamber 201 flows in parallel between the wafers 200 and is then exhausted from the exhaust pipe 231. At this time, the opening degree of the APC valve 251 is adjusted to maintain the pressure in the processing chamber 201 within a range of 30 Pa to 500 Pa, for example, 60 Pa. When the predetermined time has elapsed, the valve 250d is closed and the supply of TMA gas into the processing chamber 201 is stopped. The supply time of the TMA gas is, for example, 10 seconds within a range of 1 second to 120 seconds. During the supply of TEMAH gas, in order to promote the supply of TMA molecules to the surface of the lower layer side HfO layer 510A, the APC valve 251 is closed to stop the exhaust, and for a predetermined time (for example, 10 seconds or less), the lower side HfO layer 510A The surface may be exposed to a high pressure atmosphere.

At this time, the gas present in the processing chamber 201 is only an inert gas such as TMA gas and bubbling N ₂ gas, and there is no oxygen-containing gas such as H ₂ O gas or O ₃ gas. Therefore, the TMA gas causes chemical adsorption (surface reaction) on the surface of the TiN film 610 without causing a gas phase reaction in the processing chamber 201, and an adsorption layer of TMA molecules having a thickness of less than one atomic layer to several atomic layers. Alternatively, an Al layer is formed. The TMA molecule adsorption layer includes a continuous adsorption layer of TMA molecules and a discontinuous adsorption layer. The Al layer includes not only a continuous layer composed of Al but also an Al thin film formed by overlapping these layers. In the following, all of these are also referred to as Al-containing layers.

  While supplying the TMA gas, the valves 250 s and 250 q are opened, and the inert gas is supplied into the inert gas supply pipes 240 s and 240 q and the gas supply nozzles 234 and 235. Thereby, it can suppress that TMA gas etc. wrap around in the gas supply nozzles 234 and 235.

(Exhaust process S232b)
Subsequently, TMA gas, reaction products, and the like remaining in the processing chamber 201 are removed by the same processing procedure and processing conditions as the exhaust process S131b of the first embodiment. By performing the exhaust process S232b, as shown in FIG. 13, the TMA gas supplied in the TMA gas supply process S232a and the O ₃ gas supplied in the H ₂ O gas supply process S232c described later are not mixed with each other. it can.

(H ₂ O gas supply step S232c)
Subsequently, H ₂ O gas as a first oxygen-containing gas is supplied into the processing chamber 201 to oxidize the Al-containing layer formed on the TiN film 610. Specifically, by the same procedure and processing conditions and the H _{2 O} gas supply step S131c of the first embodiment, it supplies the H _{2 O} gas as a first oxygen-containing gas into the processing chamber 201.

The H ₂ O gas supplied to each of the laminated wafers 200 comes into contact with the Al-containing layer on the lower layer side HfO layer 510A to oxidize it, and an AlO layer having a thickness of less than one atomic layer to several atomic layers ( An aluminum oxide layer) is formed. Note that the lower HfO layer 510A formed in steps S231a to S231e suppresses the contact between the TiN film 610 and the H ₂ O gas to some extent, so that the oxidation of the TiN film 610 is suppressed. Even if the TiN film 610 and the H ₂ O gas are in direct contact, the oxidation of the TiN film 610 is suppressed because the H ₂ O gas has a weak oxidizing power.

(Exhaust process S232d)
Subsequently, H ₂ O gas remaining in the processing chamber 201, reaction products, and the like are removed by the same processing procedure and processing conditions as the exhaust process S132d of the first embodiment. By carrying out the evacuation step S232d, mixed as shown in FIG. 13, and the _{H 2} O gas was fed with _{H 2} O gas supply step S203, the TMA gas supplied by TMA gas supply step S232a of the next cycle to each other You can avoid it.

(Predetermined number of steps S232e)
Thereafter, the TMA gas supply step S232a to the exhaust step S232d are set as one cycle, this cycle is performed a predetermined number of times, and an AlO layer having a thickness of less than one atomic layer to several atomic layers formed using H ₂ O gas is sequentially formed. By laminating, a lower layer side AlO layer 520A having a predetermined thickness is formed on the lower layer side HfO layer 510A (see FIG. 10).

(Predetermined number of execution steps S233)
Subsequently, the step of forming the lower layer side HfO layer 510A (S231a to S231e) and the step of forming the lower layer side AlO layer 520A (S232a to S232e) are set as one set, and this set is performed a predetermined number of times. A first HfAlO layer 530A is formed on the TiN film 610 as a first metal oxide layer in which HfO layers 510A and lower-layer side AlO layers 520A are alternately and sequentially stacked (see FIG. 10).

As described above, in the first step (steps S231a to S233), H ₂ O gas having a relatively weak oxidizing power is used as the first oxygen-containing gas. As a result, the oxidation of the TiN film 610 as a base can be suppressed. However, a metal oxide film formed using H ₂ O gas has a leakage current higher than that of a metal oxide film having an equivalent film thickness formed using an oxygen-containing gas such as O ₃ gas having strong oxidizing power. There is a tendency that EOT increases and EOT increases. Therefore, it is preferable to adjust so that the film thickness of the first HfAlO layer 530A does not become too thick. For example, the thickness of the first HfAlO layer 530A is preferably 4 nm or less.

If the thickness of the first HfAlO layer 530A is too thin, the second oxygen-containing gas used in the second step (S234a to S236) described later is supplied to the TiN film 610 via the first HfAlO layer 530A. As a result, the TiN film 610 may be oxidized. That is, in order for the first HfAlO layer 530A to function as an antioxidant film that suppresses the oxidation of the base (TiN film 610), for example, the thickness of the first HfAlO layer 530A is preferably set to 1 nm or more.

  Subsequently, the second step (S234a to S236) will be described.

(Formation process of upper layer side HfO layer 560A)
The TMAH gas supply process S234a, the exhaust process S234b, the O ₃ gas supply process S234c, and the exhaust process S234d are performed as a cycle, and this cycle is performed a predetermined number of times, thereby forming a lower-layer side HfO layer 510A having a predetermined thickness on the TiN film 610. Form. This process is performed in the same processing procedure and processing conditions as the second process (S132a to S132e) of the first embodiment.

(Formation process of upper layer side AlO layer 570A)
Subsequently, the following steps S235a to S235e are performed to form an upper AlO layer 570A having a predetermined thickness on the upper HfO layer 560A.

(TMA gas supply step S235a)
TMA gas is supplied into the processing chamber 201 by the same processing procedure and processing conditions as the TMA gas supply step S232a of the present embodiment, and Al having a thickness of less than one atomic layer to several atomic layers is formed on the upper HfO layer 560A. A containing layer is formed.

(Exhaust process S235b)
Subsequently, TMA gas, reaction products, and the like remaining in the processing chamber 201 are removed by the same processing procedure and processing conditions as in the exhaust process S232b of the present embodiment.

(O ₃ gas supply step S235c)
Subsequently, the upper layer side HfO layer 560A is supplied by supplying O ₃ gas as the second oxygen-containing gas into the processing chamber 201 by the same processing procedure and processing conditions as the O ₃ gas supply step S132c of the first embodiment. The Al-containing layer formed above is oxidized to form an AlO layer having a thickness of less than one atomic layer to several atomic layers.

(Exhaust process S235d)
Subsequently, O ₃ gas, reaction products, and the like remaining in the processing chamber 201 are removed by the same processing procedure and processing conditions as in the exhaust process S232d of the present embodiment.

(Predetermined number of steps S232e)
Thereafter, the TMA gas supply step S232a to the exhaust step S232d are set as one cycle, this cycle is performed a predetermined number of times, and an AlO layer having a thickness of less than one atomic layer to several atomic layers formed using O ₃ gas is sequentially laminated. As a result, an upper AlO layer 570A having a predetermined thickness is formed on the upper HfO layer 560A (see FIG. 10).

(Predetermined number of execution steps S233)
Subsequently, the process of forming the upper layer side HfO layer 560A (S234a to S234e) and the formation of the upper layer side AlO layer 570A (processes S235a to S235e) are performed as a set, and this set is performed a predetermined number of times, and the upper layer side HfO layer A second HfAlO layer 580A is formed on the first HfAlO layer 530A as a second metal oxide layer in which 560A and upper layer side AlO layers 570A are alternately and sequentially stacked. As a result, an HfAlO film 600A as a metal oxide film in which the first HfAlO layer 530A and the second HfAlO layer 580A are stacked is formed on the TiN film 610 (see FIG. 10).

(Atmospheric pressure return step S240)
After the HfAlO film 600A having a predetermined thickness is formed, the opening degree of the APC valve 231a is decreased, the valves 250p, 250q, and 250s are opened, and the processing chamber 201 is kept at atmospheric pressure until the pressure in the processing chamber 201 becomes atmospheric pressure. An inert gas such as N ₂ gas is supplied into the inside. Further, the output of the heater 207 is lowered to lower the temperature in the processing chamber 201.

(Substrate unloading step S250)
Then, the boat 217 is unloaded from the processing chamber 201 (boat unloading), and the deposited wafers 200 are detached from the boat 217 (wafer discharge) in the reverse order of the substrate loading step S210 described above. The step of forming the capacitor insulating film according to the embodiment is completed. At this time, it is preferable that the valves 250p, 250q, and 250s are opened and the purge gas is continuously supplied into the processing chamber 201.

(2) Effects according to the present embodiment According to the present embodiment, the same effects as those of the above-described embodiment can be obtained.

  Furthermore, according to the present embodiment, the annealing temperature for changing the crystal structure from amorphous to tetragonal system by adding Al in the HfO film is, for example, a predetermined range of 400 ° C. to 700 ° C. Can be greatly reduced to temperature. As an example, when the Al composition ratio is in the range of 1 to 10%, the above-described annealing temperature can be lowered to about 600 ° C. If the Al composition ratio is 8% or more, the HfAlO film 600A can be phase-transformed into a tetragonal crystal structure with a probability of almost 100%. When the Al composition ratio is 16% or more, the annealing temperature is about 700 ° C.

  Further, according to the present embodiment, the dielectric constant of the HfAlO film 600A can be significantly increased by causing the crystal structure of the HfAlO film 600A to phase change to a tetragonal system. Specifically, the relative dielectric constant (k) of the HfAlO film 600A is higher than the relative dielectric constant (k = 15 to 40) of the HfO film and the relative dielectric constant (k = 6 to 13) of the AlO film. Thus, for example, k = 40.

  Further, according to the present embodiment, the Al composition ratio in the HfAlO film 600A is the film thickness ratio between the lower layer side HfO layer 510A and the lower layer side AlO layer 520A, or the upper layer side HfO layer 560A and the upper layer side AlO layer 570A. It can be easily controlled by adjusting the film thickness ratio. That is, it can be easily controlled by adjusting the ratio of the number of cycles described above.

<Other Embodiments of the Present Invention>
As mentioned above, although embodiment of this invention was described concretely, this invention is not limited to the above-mentioned embodiment, It can change variously in the range which does not deviate from the summary.

For example, in the above-described embodiment, a gas obtained by vaporizing TEMAH, which is an Hf-containing gas, is used as the metal-containing gas. However, the present invention is not limited to this mode, and for example, Hf (O-tBu) ₄ , TDMAH ( Metal containing gas vaporized tetrakisdimethylaminohafnium, Hf (NMe ₂ ) ₄ ), TDEAH (tetrakisdiethylaminohafnium, Hf (NEt ₂ ) ₄ ), Hf (MMP) ₄ , hafnium tetrachloride (HfCl ₄ ), etc. It can also be used as a gas. In the above chemical formula, “Et” is C ₂ H ₅ , “Me” is CH ₃ , “O-tBu” is OC (CH ₃ ) ₃ , and “MMP” is OC (CH ₃ ) ₂ CH _2. OCH ₃ to represent each.

For example, in the above-described embodiment, H ₂ O gas is used as the first oxygen-containing gas. However, the present invention is not limited to such an embodiment, and for example, N ₂ O gas or the like may be used.

Further, for example, in the above-described embodiment, the O ₃ gas is used as the second oxygen-containing gas having strong oxidizing power. However, the present invention is not limited to such an embodiment, and for example, an oxygen-containing substance activated by plasma (For example, O ₂ gas or the like) may be used.

In the above-described embodiment, the case where the HfO film or the HfAlO film is formed as the metal oxide film has been described. However, the present invention is not limited to the embodiment. For example, the present invention can also be suitably applied when a ZrO film (zirconium oxide film) or a ZrAlO film (zirconium aluminum oxide film) is formed as the metal oxide film. When forming a ZrO film, for example, TEMAZ (tetraethylmethylaminozirconium: Zr [N (CH ₃ ) ₂ (C ₂ H ₅ ) ₂ ] ₄ ), TDMAZ (tetrakisdimethylaminozirconium: Zr [N (CH ₃ ) ₂ ] ₄ ), Zr (NEtMe) ₄ , Zr (O-tBu) ₄ , Zr (NMe ₂ ) ₄ , Zr (NEt ₂ ) ₄ , gas obtained by vaporizing Zr (MMP) ₄ , or the like may be used. it can. In addition, a TiO film (titanium oxide film), an NbO film (niobium oxide film), a TaO film (tantalum oxide film), a film doped with Al or the like, or a metal oxide film obtained by combining or mixing them is formed. Even in this case, the present invention can be preferably applied.

  In the above-described embodiment, the metal oxide film is formed immediately above the electrode, but the present invention is not limited to such an embodiment. For example, an insulating film or the like different from the above-described metal oxide film may be provided immediately above the electrode, and the metal oxide film may be formed immediately above this film.

  In the above-described embodiment, the example in which the metal oxide film is formed by laminating the first metal oxide layer and the second oxide layer one by one has been described. However, the present invention is limited to such an embodiment. Not. For example, the first metal oxide layer and the second metal oxide layer may be alternately and repeatedly stacked. In addition, if the first metal oxide layer is formed immediately above the electrode, the first metal oxide layer and the second metal oxide layer may be arbitrarily combined as the upper layer. For example, when the HfAlO layer is formed by alternately stacking HfO layers and AlO layers, the HfO layer is not limited to being formed first, but may be formed first from the AlO layer.

  Further, as a substrate processing apparatus for performing the manufacturing method according to the present embodiment, a vertical processing furnace has been described as an example, but the present invention can also be applied to, for example, a substrate processing apparatus having a single processing furnace. is there. Further, not only the metal oxide film but also a series of steps including the formation of the lower electrode and the upper electrode can be performed in the same processing furnace.

  Further, in the above-described embodiment, the case where a DRAM having an MIM structure capacitor is manufactured has been described as an example, but the present invention is not limited to such a form. For example, the present invention can be suitably applied to the case where other metal oxide films such as capacitor insulating films of trench type DRAMs and stacked type DRAMs, gate insulating films of MOSFETs and flash memories, and charge holding films are formed. .

Example 1
Example 1 of the present invention will be described below. FIG. 14 shows film characteristics of an HfO film (Example: ▲) formed using H ₂ O gas and O ₃ gas, and an HfO film (Comparative Example: ♦) formed using only H ₂ O gas. It is a graph which shows the evaluation result of. The horizontal axis of FIG. 14 shows the EOT (nm) of the formed HfO film, and the vertical axis shows the leakage current density (A / V) when a voltage of ± 1.5 V is applied between the upper and lower electrodes sandwiching the formed HfO film. cm ² ). Note that the HfO film according to this example is formed by the same method as in the first embodiment. The film forming temperatures are 150 ° C. and 220 ° C., respectively.

According to FIG. 14, the leakage current density of the HfO film (Example) formed using H ₂ O gas and O ₃ gas is H ₂ O regardless of whether the film formation temperature is 150 ° C. or 220 ° C. It can be seen that the leakage current density of the HfO film (comparative example) formed using only gas is significantly reduced. This is presumably because the use of not only H ₂ O gas but also O ₃ gas having strong oxidizing power promotes oxidation of the HfO film and increases the dielectric constant of the HfO film. FIG. 14 also shows that EOT can be reduced by lowering the film formation temperature from 220 ° C. to 150 ° C. This is presumably because the oxidation reaction of the H ₂ O gas and O ₃ gas is suppressed by lowering the film formation temperature, and the oxidation of the base (lower electrode) is suppressed.

(Example 2)
Next, a second embodiment of the present invention will be described. FIG. 15 shows the film characteristics of an HfAlO film formed using H ₂ O gas and O ₃ gas (Example: ▲) and an HfAlO film formed using only O ₃ gas (Comparative example: ●). It is a graph which shows an evaluation result. The horizontal axis in FIG. 15 shows the actual film thickness (nm) of the formed HfO film, and the vertical axis shows the EOT of the formed HfO film. Note that the HfO film according to this example is formed by the same method as in the second embodiment described above.

According to FIG. 15, the EOT of the HfAlO film (Example) formed using H ₂ O gas and O ₃ gas is compared with the EOT of the HfAlO film (Comparative Example) formed using only O ₃ gas. It can be seen that the thickness decreases by about 0.2 nm to 0.3 nm. This is a result of suppressing the oxidation of the base (lower electrode) by using the H ₂ O gas having a weak oxidizing power in the initial stage of film formation without using only the O ₃ gas having a strong oxidizing power. Conceivable.

<Preferred embodiment of the present invention>
Hereinafter, desirable aspects of the present invention will be additionally described.

[Appendix 1]
One embodiment of the present invention provides:
A substrate carrying-in step of carrying the substrate on which the electrode is formed into the processing chamber;
A metal oxide film forming step of forming a metal oxide film on the electrode of the substrate;
A substrate unloading step of unloading the substrate on which the metal oxide film has been formed from the processing chamber;
Have
In the metal oxide film forming step,
A step of supplying at least one metal-containing gas into the processing chamber and a step of supplying a first oxygen-containing gas into the processing chamber are performed, and a first metal oxide layer is formed immediately above the electrode. A first step of:
Supplying the metal-containing gas into the processing chamber; and supplying a second oxygen-containing gas having a stronger oxidizing power than the first oxygen-containing gas into the processing chamber; A second step of forming a second metal oxide layer on the metal oxide layer;
Is a method for manufacturing a semiconductor device in which the steps are performed in this order.

[Appendix 2]
Preferably,
In the first step,
Supplying the metal-containing gas into the processing chamber;
The step of supplying the first oxygen-containing gas into the processing chamber is defined as one cycle, and this cycle is performed a predetermined number of times.

[Appendix 3]
Also preferably,
In the second step,
Supplying the metal-containing gas into the processing chamber;
The step of supplying the second oxygen-containing gas into the processing chamber is defined as one cycle, and this cycle is performed a predetermined number of times.

[Appendix 4]
Also preferably,
In the metal oxide film forming step,
The first step and the second step are continuously performed in the same processing chamber.

[Appendix 5]
Also preferably,
In the metal oxide film forming step,
H ₂ O gas or N ₂ O gas is used as the first oxygen-containing gas,
O ₃ gas is used as the second oxygen-containing gas.

[Appendix 6]
Also preferably,
In the first step,
The first metal oxide layer is formed so that the film thickness is at least 1 nm or more.

[Appendix 7]
Another aspect of the present invention is:
A processing chamber for accommodating a substrate on which an electrode is formed;
A metal-containing gas supply system for supplying at least one metal-containing gas into the processing chamber;
A first oxygen-containing gas supply system for supplying a first oxygen-containing gas into the processing chamber;
A second oxygen-containing gas supply system for supplying a second oxygen-containing gas having a stronger oxidizing power than the first oxygen-containing gas into the processing chamber;
An exhaust system for exhausting the atmosphere in the processing chamber;
Performing a process of supplying the metal-containing gas into the processing chamber and a process of supplying the first oxygen-containing gas into the processing chamber, forming a first metal oxide layer directly on the electrode, A process of supplying the metal-containing gas into a processing chamber and a process of supplying the second oxygen-containing gas into the processing chamber are performed to form a second metal oxide layer on the first metal oxide layer And a control unit for controlling the metal-containing gas supply system, the first oxygen-containing gas supply system, the second oxygen-containing gas supply system, and the exhaust system so as to form a metal oxide film. It is a processing device.

[Appendix 8]
Preferably,
The controller is
In the process of forming the first metal oxide layer, the process of supplying the metal-containing gas into the process chamber and the process of supplying the first oxygen-containing gas into the process chamber are defined as one cycle. Is performed a predetermined number of times.

[Appendix 9]
Also preferably,
The controller is
In the process of forming the second metal oxide layer, the process of supplying the metal-containing gas into the process chamber and the process of supplying the second oxygen-containing gas into the process chamber are defined as one cycle. Is performed a predetermined number of times.

[Appendix 10]
Still another aspect of the present invention provides:
A processing chamber for accommodating a substrate on which an electrode is formed;
A metal-containing gas supply system for supplying at least one metal-containing gas into the processing chamber;
A first oxygen-containing gas supply system for supplying a first oxygen-containing gas into the processing chamber;
A second oxygen-containing gas supply system for supplying a second oxygen-containing gas having a stronger oxidizing power than the first oxygen-containing gas into the processing chamber;
An exhaust system for exhausting the atmosphere in the processing chamber;
A process of supplying the metal-containing gas into the processing chamber and a process of supplying the first oxygen-containing gas into the processing chamber are performed to form a first metal oxide layer on the electrode, and the processing A process of supplying the metal-containing gas into the chamber and a process of supplying the second oxygen-containing gas into the process chamber are performed to form a second metal oxide layer on the first metal oxide layer. A control unit for controlling the metal-containing gas supply system, the first oxygen-containing gas supply system, the second oxygen-containing gas supply system, and the exhaust system so as to form a metal oxide film,
The controller is
In the substrate processing apparatus, the process for forming the first metal oxide layer and the process for forming the second metal oxide layer are continuously performed in the same processing chamber.

[Appendix 11]
Preferably,
The controller is
In the process of forming the first metal oxide layer, the first metal oxide layer having a thickness of at least 1 nm is formed.

200 wafer (substrate)
201 treatment chamber 510 first HfO layer (first metal oxide layer)
560 Second HfO layer (second metal oxide layer)
530A first HfO layer (first metal oxide layer)
580A Second HfO layer (second metal oxide layer)
600 HfO film (metal oxide film)
610 Lower electrode (electrode)

Claims (3)

A substrate carrying-in step of carrying the substrate on which the electrode is formed into the processing chamber;
A metal oxide film forming step of forming a metal oxide film directly on the electrode of the substrate;
A substrate unloading step of unloading the substrate on which the metal oxide film has been formed from the processing chamber;
Have
In the metal oxide film forming step,
A step of supplying at least one metal-containing gas into the processing chamber and a step of supplying a first oxygen-containing gas into the processing chamber are performed to form a first metal oxide layer on the electrode. A first step;
Supplying the metal-containing gas into the processing chamber; and supplying a second oxygen-containing gas having a stronger oxidizing power than the first oxygen-containing gas into the processing chamber; A second step of forming a second metal oxide layer on the metal oxide layer;
Are performed in this order. A method for manufacturing a semiconductor device. In the metal oxide film forming step,
H ₂ O gas or N ₂ O gas is used as the first oxygen-containing gas,
The method for manufacturing a semiconductor device according to claim 1, wherein an O ₃ gas is used as the second oxygen-containing gas. A processing chamber for accommodating a substrate on which an electrode is formed;
A metal-containing gas supply system for supplying at least one metal-containing gas into the processing chamber;
A first oxygen-containing gas supply system for supplying a first oxygen-containing gas into the processing chamber;
A second oxygen-containing gas supply system for supplying a second oxygen-containing gas having a stronger oxidizing power than the first oxygen-containing gas into the processing chamber;
An exhaust system for exhausting the atmosphere in the processing chamber;
Performing a process of supplying the metal-containing gas into the processing chamber and a process of supplying the first oxygen-containing gas into the processing chamber, forming a first metal oxide layer directly on the electrode, A process of supplying the metal-containing gas into a processing chamber and a process of supplying the second oxygen-containing gas into the processing chamber are performed to form a second metal oxide layer on the first metal oxide layer And a control unit for controlling the metal-containing gas supply system, the first oxygen-containing gas supply system, the second oxygen-containing gas supply system, and the exhaust system so as to form a metal oxide film. ,
The controller is
A substrate processing apparatus, wherein the process for forming the first metal oxide layer and the process for forming the second metal oxide layer are continuously performed in the same processing chamber.