JP2012059834A - Method for manufacturing semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a semiconductor device capable of improving controllability of a composition ratio of a first metal element and a second metal element in a third metal oxide film during a formation of the third metal oxide film having the first metal element and the second metal element.SOLUTION: The method for manufacturing the semiconductor device comprises: a step for forming a first metal oxide film by performing at least one cycle comprising a step for supplying and exhausting a first raw material having a first metal element and a step for supplying and exhausting an oxidant; a step for forming a second metal oxide film by performing at least one cycle comprising a step for supplying and exhausting a second raw material having a second metal element and a step for supplying and exhausting an oxidant; and a step for forming a third metal oxide film by alternately performing their cycles by predetermined times. Raw materials that a film thickness formed per one cycle in the formation of the second metal oxide film is thinner than that in the formation of the first metal oxide film, is used for the first and the second raw materials.

Description

  The present invention relates to a method for manufacturing a semiconductor device including a step of forming a metal oxide film on a substrate.

  In order to advance the miniaturization of the DRAM while maintaining the capacitor capacity, for example, it is necessary to reduce the film thickness of the high dielectric constant insulating film used for the capacitor insulating film or increase the dielectric constant of the high dielectric constant insulating film. . The thinning of the high dielectric constant insulating film may lead to an increase in leakage current in the capacitor, an increase in power consumption in the device, and a decrease in memory retention capability. Therefore, the appearance of a high dielectric constant insulating film having a higher dielectric constant is demanded. In recent years, methods for increasing the dielectric constant by adding other elements to the high dielectric constant insulating film have been studied. For example, the dielectric constant can be increased by adding aluminum (Al) as another element in the hafnium oxide (HfO) film.

  The HfAlO film in which Al is added to the HfO film includes a step of forming an HfO film (first metal oxide film) containing Hf (first metal element) and an oxidation containing Al (second metal element). The step of forming an aluminum (AlO) film (second metal oxide film) and the step of alternately performing a predetermined number of times can be performed. The composition ratio between Hf and Al in the HfAlO film is determined by the film thicknesses of the HfO film and the AlO film formed in each process described above. However, depending on the target composition ratio, it may be difficult to freely control the composition ratio. For example, it has been difficult to perform a trace composition control that reduces the composition ratio of Al to Hf within several percent.

  Therefore, according to the present invention, when the third metal oxide film containing the first metal element and the second metal element is formed, the first metal element and the second metal element in the third metal oxide film are formed. It is an object to provide a method for manufacturing a semiconductor device capable of improving the controllability of the composition ratio.

  According to one embodiment of the present invention, the process of supplying and exhausting the first raw material containing the first metal element and the process of supplying and exhausting the oxidizing agent into the processing chamber containing the substrate are performed as one cycle. By performing the cycle at least once, a step of forming a first metal oxide film containing the first metal element on the substrate and supplying a second raw material containing the second metal element into the processing chamber The second metal oxide film containing the second metal element is formed on the substrate by performing this cycle at least once with the step of exhausting and the step of supplying and exhausting the oxidizing agent as one cycle. And a step of forming a third metal oxide film containing the first metal element and the second metal element on the substrate by alternately performing a predetermined number of times, the first material And each said metal oxide film as said 2nd raw material When formed in the same film formation mode, the film thickness formed per cycle in the step of forming the second metal oxide film is formed per cycle in the step of forming the first metal oxide film. A method of manufacturing a semiconductor device using a raw material that is smaller than the film thickness is provided.

  According to the method for manufacturing a semiconductor device of the present invention, when forming the third metal oxide film containing the first metal element and the second metal element, the first metal in the third metal oxide film is formed. The controllability of the composition ratio of the element and the second metal element can be improved.

It is a block diagram of the gas supply system which the substrate processing apparatus concerning one Embodiment of this invention has. It is a flowchart of the substrate processing process concerning one Embodiment of this invention. It is a section lineblock diagram at the time of wafer processing of a substrate processing device concerning one embodiment of the present invention. It is a section lineblock diagram at the time of wafer conveyance of a substrate processing device concerning one embodiment of the present invention. Examples of the timings of supplying each of a first raw material supply in an ALD saturation mode, an oxidant supply, a second raw material supply in an ALD saturation mode, and an oxidant supply alternately according to an embodiment of the present invention are performed a predetermined number of times. It is a sequence diagram as a timing chart. It is the schematic which shows the adsorption state of the raw material gas molecule to the wafer surface in ALD saturation mode. It is the cross-sectional schematic of the HfAlO film | membrane formed by laminating | stacking the HfO film | membrane with a film thickness of 1.11 ?, and the AlO film | membrane with a film thickness of 0.09? In order of HfO and AlO. It is the cross-sectional schematic of the HfAlO film | membrane formed by laminating | stacking the HfO film | membrane with a film thickness of 1.11 ?, and the AlO film | membrane with a film thickness of 0.09? In order of HfO, HfO, and AlO. It is a graph which shows the relationship (CVD mode) of the Hf raw material supply time per cycle and the film thickness of the HfO film | membrane formed per cycle. It is a graph which shows the relationship (ALD saturation mode) of the Hf raw material supply time per cycle and the film thickness of the HfO film | membrane formed per cycle. It is a graph which shows the relationship between the number of cycles and the film thickness of the AlO film | membrane formed in that case. It is a schematic block diagram of the vertical processing furnace of the vertical apparatus concerning other embodiment of this invention, (a) shows a processing furnace part with a longitudinal cross-section, (b) shows a processing furnace part (a). It is shown by the AA line sectional view.

  First, prior to the description of the embodiment of the present invention, knowledge obtained by the inventors will be described.

(Knowledge about trace composition control)
The composition ratio of the first metal element and the second metal element in the third metal oxide film is the film thickness of the first metal oxide film formed for each of the above steps, and the second metal It is determined by the thickness of the oxide film.

  For the formation of the first metal oxide film and the second metal oxide film, in addition to the CVD (Chemical Vapor Deposition) method, an ALD (Atomic Layer Deposition) method effective for accurately controlling the film thickness is used. Yes. In the case of using the ALD method, the step of forming the first metal oxide film includes a step (cycle) of alternately supplying the first raw material containing the first metal element and the oxidizing agent into the processing chamber containing the substrate. Do more than once. Further, in the step of forming the second metal oxide film, the step (cycle) of alternately supplying the second raw material containing the second metal element and the oxidizing agent into the processing chamber containing the substrate is performed one or more times. Then, by adjusting the number of executions of the cycle in the step of forming the first metal oxide film and the number of executions of the cycle in the step of forming the second metal oxide film, respectively, The thickness of the second metal oxide film is set to a predetermined thickness, and the composition of the third metal oxide film is controlled.

For example, a step of forming an HfO ₂ film (hafnium oxide film; hereinafter also referred to as an HfO film) containing Hf (hafnium) on the substrate, and an Al ₂ O ₃ film (aluminum oxide film; containing aluminum (Al)). The step of forming an AlO film) is alternately performed a predetermined number of times to form an HfAlO (hafnium aluminate) film on the substrate. Note that Hf is the first metal element, Al is the second metal element, HfO film is the first metal oxide film, AlO film is the second metal oxide film, and HfAlO film is the third metal oxide. Corresponds to the membrane. When the ALD method is used, in the step of forming the HfO film, one cycle is Hf source introduction into the processing chamber containing the substrate → Hf source purge → oxidant introduction → oxidant purge, and this cycle is performed once or more. Further, in the step of forming the AlO film, the Al source introduction into the processing chamber containing the substrate → Al source purge → oxidant introduction → oxidant purge is set as one cycle, and this cycle is performed once or more.

  If the thickness of the HfO film formed per cycle and the thickness of the AlO film formed per cycle are both 1 mm, the composition ratio of HfO and AlO in the HfAlO film is 1: 1. In order to achieve this, the number of cycles executed in the step of forming the HfO film and the number of cycles executed in the step of forming the AlO film may be the same. For example, the number of cycles executed in the step of forming the HfO film and the number of cycles executed in the step of forming the AlO film may both be set to one. Then, the process of forming the HfO film and the process of forming the AlO film are alternately performed 50 times each, that is, the process of forming the HfO film and the process of forming the AlO film are set as one set. 50 times, the HfOO film and the AlO film are alternately stacked with a thickness of about 1 mm each, so that the composition ratio of HfO and AlO is 1: 1 and the film thickness is 100 mm. A film can be formed.

  As described above, when the HfO film and the AlO film are alternately stacked with a thickness of about 1 mm, Hf and Al diffuse between the HfO film and the AlO film during the film formation. As a result, the composition ratio of the HfAlO film becomes uniform in the film thickness direction.

  However, the inventors have found that depending on the target composition ratio of the third metal oxide film, it may be difficult to control the composition ratio of the third metal oxide film. For example, HfAlO in which the thickness of the HfO film formed per cycle and the thickness of the AlO film formed per cycle are both 1 mm and the composition ratio of HfO and AlO is 4: 1. In the case of forming a film, the number of executions of the cycle in the step of forming the HfO film is four times, the number of executions of the cycle in the step of forming the AlO film is one, the HfO film having a thickness of 4 mm, and the film thickness is One AlO film is alternately laminated. However, when forming an HfAlO film in which the composition ratio of HfO and AlO is 19: 1, the number of cycles in the process of forming the HfO film increases, and it is difficult to maintain the target composition ratio. It becomes. That is, aiming at a low concentration of the AlO film leads to an increase in the number of cycles of the process of forming the HfO film, that is, an increase in the film thickness of the HfO film, and mutual diffusion of HfO and AlO between the HfO film and the AlO film. May become insufficient, and the composition ratio of HfO and AlO in the HfAlO film may become uneven in the film thickness direction. Such a problem arises when the composition ratio (ratio) of one element among a plurality of elements constituting the metal oxide film is controlled to be within a few percent, for example, 1 to 10%, that is, when a small amount of composition is controlled. , Especially manifest.

  The inventors have conducted intensive research on methods for solving the above-described problems. As a result, each film forming step for forming two or more types of metal oxide films on the substrate by the CVD method or the ALD method is alternately performed a predetermined number of times to form a metal oxide film having a predetermined composition containing two or more types of metal elements. When the thickness of each metal oxide film formed per cycle is close, that is, when the deposition rate of each metal oxide film is close, one metal element among a plurality of metal elements in the entire metal oxide film It was found difficult to control the composition of a trace amount so that the composition ratio is within a few percent.

On the other hand, as a result of earnest research, the inventors have used two or more kinds of raw materials having greatly different film formation rates and greatly changed the thicknesses of two or more kinds of metal oxide films formed per cycle. It was considered that the controllability of the composition ratio of the metal element in the third metal oxide film can be improved. That is, by using two or more kinds of raw materials having greatly different film formation rates, the composition ratio is smaller than the film thickness formed per cycle of the metal oxide film containing the metal element having the largest composition ratio. The film thickness formed per cycle of the metal oxide film containing the metal element is about 1/5 to 1/10. Thereby, the knowledge that it was possible to implement | achieve the above trace composition control was acquired.

  For example, when an HfAlO film having a composition ratio of HfO and AlO of approximately 10: 1 is formed, by using two or more kinds of raw materials having greatly different film formation rates, as shown in FIG. The film thickness of the HfO film (metal oxide film containing the metal element with the largest composition ratio) formed around 1.11 mm is the AlO film (metal element with a composition ratio smaller than Hf) formed per cycle. The thickness of the metal oxide film is 0.09 mm. The number of cycles executed in the step of forming the HfO film and the number of cycles executed in the step of forming the AlO film are both set to one, and these steps are alternately performed a predetermined number of times. As a result, a metal oxide film having a predetermined composition (HfO: AlO = 10: 1) is obtained, and HfO and AlO are diffused in the middle of the film formation, so that the composition of the HfAlO film is in both the in-plane direction and the film thickness direction. It becomes uniform. FIG. 7 shows a state before HfO and AlO are interdiffused for convenience.

  Further, when forming an HfAlO film having a composition ratio of HfO and AlO of approximately 20: 1, as shown in FIG. The film thickness of the HfO film (metal oxide film containing the metal element with the largest composition ratio) formed around 1.11 mm is the AlO film (metal element with a composition ratio smaller than Hf) formed per cycle. The thickness of the metal oxide film is 0.09 mm. Then, the number of executions of the cycle in the process of forming the HfO film is set to two, and the number of executions of the cycle in the process of forming the AlO film is set to one, and these processes are alternately performed a predetermined number of times. As a result, a metal oxide film having a predetermined composition (HfO: AlO = 20: 1) is obtained, and HfO and AlO are diffused during the film formation, so that the composition of the HfAlO film is in both the in-plane direction and the film thickness direction. It becomes uniform. FIG. 8 shows a state before HfO and AlO are interdiffused for convenience.

  The inventors have found that the above-described HfO film may be formed using either the CVD mode or the ALD saturation mode, and the AlO film is preferably formed using the ALD saturation mode. The CVD mode is a mode in which a film is formed by supplying a source gas with a processing temperature (substrate temperature) set to a temperature at which the source gas is self-decomposed. In addition, the ALD saturation mode is that the processing temperature (substrate temperature) is set to a temperature at which the source gas is not self-decomposed, and the amount of source gas molecules adsorbed on the substrate is saturated (adsorption of source gas molecules on the substrate). Is a mode in which a source gas is supplied until film formation occurs (see FIG. 6). In the CVD mode, a relatively high film formation rate can be obtained, so that the time required for forming a thin film can be shortened and the productivity of substrate processing can be improved. In the ALD saturation mode, an extremely thin thin film can be formed by utilizing the phenomenon that the adsorption of the source gas molecules on the substrate is saturated. In the ALD saturation mode, since the amount of raw material gas molecules adsorbed on the substrate is stable, the thickness of the thin film formed per cycle can be stabilized, and the number of cycles can be controlled by controlling the number of cycles. It becomes possible to adjust the film thickness of the thin film with good reproducibility.

  The present invention is based on the above findings found by the inventors.

<One Embodiment of the Present Invention>
An embodiment of the present invention will be described below with reference to the drawings.

(1) Configuration of Substrate Processing Apparatus First, the configuration of the substrate processing apparatus according to the present embodiment will be described with reference to FIGS. FIG. 3 is a cross-sectional configuration diagram of the substrate processing apparatus according to one embodiment of the present invention during wafer processing, and FIG. 4 is a cross-sectional configuration diagram of the substrate processing apparatus according to one embodiment of the present invention during wafer transfer. is there.

(Processing room)
As shown in FIGS. 3 and 4, the substrate processing apparatus according to this embodiment includes a processing container 202. The processing container 202 is configured as a flat sealed container having a circular cross section, for example. Moreover, the processing container 202 is comprised, for example with metal materials, such as aluminum (Al) and stainless steel (SUS). A processing chamber 201 for processing a wafer 200 such as a silicon wafer as a substrate is formed in the processing container 202.

A support table 203 that supports the wafer 200 is provided in the processing chamber 201. For example, quartz (SiO ₂ ), carbon, ceramics, silicon carbide (SiC), aluminum oxide (Al ₂ O ₃ ), or aluminum nitride (AlN) is formed on the upper surface of the support base 203 that the wafer 200 directly touches. A susceptor 217 is provided as a support plate. In addition, the support base 203 incorporates a heater 206 as a heating means (heating source) for heating the wafer 200. Note that the lower end portion of the support base 203 passes through the bottom portion of the processing container 202.

  Outside the processing chamber 201, an elevating mechanism 207b for elevating the support base 203 is provided. The wafer 200 supported on the susceptor 217 can be moved up and down by operating the lifting mechanism 207 b to raise and lower the support base 203. The support table 203 is lowered to the position shown in FIG. 4 (wafer transfer position) when the wafer 200 is transferred, and is raised to the position shown in FIG. 3 (wafer processing position) when the wafer 200 is processed. The periphery of the lower end portion of the support base 203 is covered with a bellows 203a, and the inside of the processing chamber 201 is kept airtight.

  In addition, on the bottom surface (floor surface) of the processing chamber 201, for example, three lift pins 208b are provided so as to rise in the vertical direction. In addition, the support base 203 (including the susceptor 217) is provided with through holes 208a through which the lift pins 208b pass, at positions corresponding to the lift pins 208b. When the support table 203 is lowered to the wafer transfer position, as shown in FIG. 4, the upper ends of the lift pins 208b protrude from the upper surface of the susceptor 217, and the lift pins 208b support the wafer 200 from below. Yes. When the support table 203 is raised to the wafer processing position, as shown in FIG. 3, the lift pins 208b are buried from the upper surface of the susceptor 217, and the susceptor 217 supports the wafer 200 from below. In addition, since the lift pins 208b are in direct contact with the wafer 200, it is desirable to form the lift pins 208b with a material such as quartz or alumina.

(Wafer transfer port)
On the inner wall side surface of the processing chamber 201 (processing container 202), a wafer transfer port 250 for transferring the wafer 200 into and out of the processing chamber 201 is provided. The wafer transfer port 250 is provided with a gate valve 251. By opening the gate valve 251, the processing chamber 201 and the transfer chamber (preliminary chamber) 271 communicate with each other. The transfer chamber 271 is formed in a transfer container (sealed container) 272, and a transfer robot 273 that transfers the wafer 200 is provided in the transfer chamber 271. The transfer robot 273 includes a transfer arm 273 a that supports the wafer 200 when the wafer 200 is transferred. By opening the gate valve 251 while the support table 203 is lowered to the wafer transfer position, the transfer robot 273 can transfer the wafer 200 between the processing chamber 201 and the transfer chamber 271. Yes. The wafer 200 transferred into the processing chamber 201 is temporarily placed on the lift pins 208b as described above. Note that a load lock chamber (not shown) is provided on the opposite side of the transfer chamber 271 from the side where the wafer transfer port 250 is provided, and the transfer robot 273 moves the wafer 200 between the load lock chamber and the transfer chamber 271. Can be transported. The load lock chamber functions as a spare chamber for temporarily storing unprocessed or processed wafers 200.

(Exhaust system)
An exhaust port 260 for exhausting the atmosphere in the processing chamber 201 is provided on the inner wall side surface of the processing chamber 201 (processing container 202) on the opposite side of the wafer transfer port 250. An exhaust pipe 261 is connected to the exhaust port 260 via an exhaust chamber 260a. The exhaust pipe 261 has a pressure regulator 262 such as an APC (Auto Pressure Controller) that controls the inside of the processing chamber 201 at a predetermined pressure. A raw material recovery trap 263 and a vacuum pump 264 are connected in series in this order. An exhaust system (exhaust line) is mainly configured by the exhaust port 260, the exhaust chamber 260a, the exhaust pipe 261, the pressure regulator 262, the raw material recovery trap 263, and the vacuum pump 264.

(Gas inlet)
A gas inlet 210 for supplying various gases into the processing chamber 201 is provided on the upper surface (ceiling wall) of a shower head 240 described later provided in the upper portion of the processing chamber 201. The configuration of the gas supply system connected to the gas inlet 210 will be described later.

(shower head)
A shower head 240 as a gas dispersion mechanism is provided between the gas inlet 210 and the processing chamber 201. The shower head 240 is a dispersion plate 240 a that disperses the gas introduced from the gas introduction port 210, and a shower plate that further uniformly disperses the gas that has passed through the dispersion plate 240 a and supplies it to the surface of the wafer 200 on the support table 203. 240b. The dispersion plate 240a and the shower plate 240b are provided with a plurality of vent holes. The dispersion plate 240 a is disposed so as to face the upper surface of the shower head 240 and the shower plate 240 b, and the shower plate 240 b is disposed so as to face the wafer 200 on the support table 203. Note that spaces are provided between the upper surface of the shower head 240 and the dispersion plate 240a, and between the dispersion plate 240a and the shower plate 240b, respectively, and the spaces are supplied from the gas inlet 210. Function as a first buffer space (dispersion chamber) 240c for dispersing the gas and a second buffer space 240d for diffusing the gas that has passed through the dispersion plate 240a.

(Exhaust duct)
A step portion 201a is provided on the side surface of the inner wall of the processing chamber 201 (processing vessel 202). The step portion 201a is configured to hold the conductance plate 204 in the vicinity of the wafer processing position. The conductance plate 204 is configured as a single donut-shaped (ring-shaped) disk in which a hole for accommodating the wafer 200 is provided in the inner periphery. A plurality of discharge ports 204 a arranged in the circumferential direction with a predetermined interval are provided on the outer periphery of the conductance plate 204. The discharge port 204 a is formed discontinuously so that the outer periphery of the conductance plate 204 can support the inner periphery of the conductance plate 204.

On the other hand, a lower plate 205 is locked to the outer peripheral portion of the support base 203. The lower plate 205 includes a ring-shaped concave portion 205b and a flange portion 205a provided integrally on the inner upper portion of the concave portion 205b. The recess 205 b is provided so as to close a gap between the outer peripheral portion of the support base 203 and the inner wall side surface of the processing chamber 201. A part of the bottom of the recess 205b near the exhaust port 260 is provided with a plate exhaust port 205c that exhausts (circulates) gas from the recess 205b to the exhaust port 260 side. The flange portion 205 a functions as a locking portion that locks on the upper outer periphery of the support base 203. When the flange portion 205 a is locked on the upper outer periphery of the support base 203, the lower plate 205 is moved up and down together with the support base 203 as the support base 203 is moved up and down.

  When the support table 203 is raised to the wafer processing position, the lower plate 205 is also raised to the wafer processing position. As a result, the conductance plate 204 held in the vicinity of the wafer processing position closes the upper surface portion of the recess 205b of the lower plate 205, and the exhaust duct 259 having the gas passage region inside the recess 205b is formed. . At this time, due to the exhaust duct 259 (the conductance plate 204 and the lower plate 205) and the support base 203, the inside of the processing chamber 201 is above the processing chamber above the exhaust duct 259 and the processing chamber below the exhaust duct 259. It will be partitioned into a lower part. The conductance plate 204 and the lower plate 205 are made of materials that can be kept at a high temperature, for example, high temperature and high load resistance, in consideration of etching reaction products deposited on the inner wall of the exhaust duct 259 (self cleaning). Preferably, it is made of quartz for use.

  Here, the flow of gas in the processing chamber 201 during wafer processing will be described. First, the gas supplied from the gas inlet 210 to the upper part of the shower head 240 enters the second buffer space 240d through the first buffer space (dispersion chamber) 240c through a large number of holes in the dispersion plate 240a, and further the shower. It passes through a large number of holes in the plate 240 b and is supplied into the processing chamber 201, and is uniformly supplied onto the wafer 200. The gas supplied onto the wafer 200 flows radially outward of the wafer 200 in the radial direction. Then, surplus gas after contacting the wafer 200 flows radially on the exhaust duct 259 located on the outer peripheral portion of the wafer 200, that is, on the conductance plate 204 toward the radially outer side of the wafer 200. Is discharged into the gas flow path region (in the recess 205b) in the exhaust duct 259. Thereafter, the gas flows through the exhaust duct 259 and is exhausted to the exhaust port 260 via the plate exhaust port 205c. By flowing the gas in this way, gas wraparound to the lower part of the processing chamber, that is, the back surface of the support base 203 or the bottom surface side of the processing chamber 201 is suppressed.

  Next, the configuration of the gas supply system connected to the gas inlet 210 described above will be described with reference to FIG. FIG. 1 is a configuration diagram of a gas supply system (gas supply line) included in a substrate processing apparatus according to an embodiment of the present invention.

(Liquid raw material supply system)
An organometallic liquid source (hereinafter also referred to as a Hf source) as a first source (hereinafter also referred to as a first liquid source) containing Hf (hafnium) as a first metal element is supplied to the outside of the processing chamber 201. The first liquid source supply source 220h, and the organometallic liquid source (hereinafter also referred to as Al source) as the second source (hereinafter also referred to as second liquid source) containing Al (aluminum) as the second metal element. And a second liquid raw material supply source 220a. The first liquid raw material supply source 220h and the second liquid raw material supply source 220a are respectively configured as tanks (sealed containers) capable of containing (filling) the liquid raw material.

Pressure gas supply pipes 237h and 237a are connected to the first liquid source supply source 220h and the second liquid source supply source 220a, respectively. A pressure gas supply source (not shown) is connected to upstream ends of the pressure gas supply pipes 237h and 237a. Further, the downstream ends of the pressurized gas supply pipes 237h and 237a communicate with spaces existing in the upper portions of the first liquid raw material supply source 220h and the second liquid raw material supply source 220a, respectively. Gas is supplied. As the pressurized gas, it is preferable to use a gas that does not react with the liquid material, for example an inert gas such as N ₂ gas is used.

  In addition, a first liquid source supply pipe 211h and a second liquid source supply pipe 211a are connected to the first liquid source supply source 220h and the second liquid source supply source 220a, respectively. Here, the upstream end portions of the first liquid source supply pipe 211h and the second liquid source supply pipe 211a are immersed in the liquid source accommodated in the first liquid source supply source 220h and the second liquid source supply source 220a, respectively. Has been. In addition, downstream end portions of the first liquid source supply pipe 211h and the second liquid source supply pipe 211a are connected to vaporizers 229h and 229a as vaporizers for vaporizing the liquid source, respectively. The first liquid source supply pipe 211h and the second liquid source supply pipe 211a are supplied with liquid flow rate controllers (LMFC) 221h and 221a as flow rate controllers for controlling the liquid supply flow rate of the liquid source and supply of the liquid source. Valves vh1 and va1 as opening / closing valves to be controlled are respectively provided. The valves vh1 and va1 are provided inside the vaporizers 229h and 229a, respectively.

  With the above configuration, the valves vh1 and va1 are opened and the pressurized gas is supplied from the pressurized gas supply pipes 237h and 237a, whereby the first liquid source supply source 220h and the second liquid source supply source 220a are supplied to the vaporizers 229h and 229a. The liquid raw material can be pumped (supplied). A first liquid source supply system (first liquid source supply line) is mainly configured by the first liquid source supply source 220h, the pressure gas supply pipe 237h, the first liquid source supply pipe 211h, the liquid flow rate controller 221h, and the valve vh1. The second liquid source supply system (second liquid source supply line) is mainly configured by the second liquid source supply source 220a, the pressurized gas supply pipe 237a, the second liquid source supply pipe 211a, the liquid flow rate controller 221a, and the valve va1. Is done.

(Vaporization Department)
The vaporizers 229h and 229a serving as vaporizers for vaporizing the liquid raw material are vaporized chambers 20h and 20a for generating the raw material gas by heating the liquid raw material with the heaters 23h and 23a and into the vaporizing chambers 20h and 20a. In the liquid source channels 21h and 21a, which are channels until the liquid source is discharged, the above-described valves vh1 and va1 for controlling the supply of the liquid source into the vaporization chambers 20h and 20a, and the vaporization chambers 20h and 20a. It has source gas supply ports 22h and 22a as outlets for supplying the generated source gas to a first source gas supply pipe 213h and a second source gas supply pipe 213a, which will be described later. The downstream end portions of the first liquid raw material supply pipe 211h and the second liquid raw material supply pipe 211a are connected to the upstream end portions of the liquid raw material channels 21h and 21a via valves vh1 and va1, respectively. The liquid source channels 21h and 21a are connected to downstream ends of carrier gas supply pipes 24h and 24a, respectively, and supply carrier gas into the vaporization chambers 20h and 20a via the liquid source channels 21h and 21a. Is configured to do. Carrier gas supply pipe 24h, the upstream end of the 24a, the _{N 2} gas supply source 230c for supplying _{N 2} gas as a carrier gas is connected. Carrier gas supply pipe 24h, the 24a, the flow rate controller (MFC) 225h as a flow rate controller for controlling the supply flow rate of _{N 2} gas, and 225a, and the valve vh2, va2 for controlling the supply of _{N 2} gas, respectively Is provided. A carrier gas supply system (carrier gas supply line) is mainly configured by the N ₂ gas supply source 230c, carrier gas supply pipes 24h and 24a, flow rate controllers 225h and 225a, and valves vh2 and va2. The vaporizers 229h and 229a are configured as a first vaporizer and a second vaporizer, respectively.

(Raw gas supply system)
The upstream side ends of the first source gas supply pipe 213h and the second source gas supply pipe 213a for supplying the source gas into the processing chamber 201 are respectively connected to the source gas supply ports 22h and 22a of the vaporizers 229h and 229a. It is connected. The downstream end portions of the first source gas supply pipe 213h and the second source gas supply pipe 213a are unified so as to join together to become the source gas supply pipe 213, and the source gas supply pipe 213 is connected to the gas inlet 210. ing. The first source gas supply pipe 213h and the second source gas supply pipe 213a are provided with valves vh3 and va3 for controlling the supply of the source gas into the processing chamber 201, respectively.

  With the above configuration, the raw material gas is generated by vaporizing the liquid raw material in the vaporizers 229h and 229a, and the raw material is supplied from the first raw material gas supply pipe 213h and the second raw material gas supply pipe 213a by opening the valves vh3 and va3. The source gas can be supplied into the processing chamber 201 through the gas supply pipe 213. The first source gas supply system (first source gas supply line) is mainly configured by the first source gas supply pipe 213h and the valve vh3, and the second source gas supply pipe 213a and the valve va3 mainly configure the second source gas supply system (first source gas supply line). A source gas supply system (second source gas supply line) is configured. The first liquid source supply system, the first vaporization unit, and the first source gas supply system constitute a first source supply system (Hf source supply system), and the second liquid source supply system, the second vaporization unit, the second source The source gas supply system constitutes a second source supply system (Al source supply system).

(Oxidant supply system)
Further, an oxygen gas supply source 230o for supplying oxygen (O ₂ ) gas is provided outside the processing chamber 201. The upstream end of the first oxygen gas supply pipe 211o is connected to the oxygen gas supply source 230o. The downstream end of the first oxygen gas supply pipe 211o is connected to an ozonizer 229o that generates a reaction gas (reactant), that is, ozone (O ₃ ) gas as an oxidant from oxygen gas by plasma. The first oxygen gas supply pipe 211o is provided with a flow rate controller (MFC) 221o as a flow rate controller for controlling the supply flow rate of oxygen gas.

  An upstream end of an ozone gas supply pipe 213o as an oxidant supply pipe is connected to an ozone gas supply port 22o as an outlet of the ozonizer 229o. The downstream end of the ozone gas supply pipe 213o is connected so as to join the source gas supply pipe 213. That is, the ozone gas supply pipe 213o is configured to supply ozone gas as an oxidizing agent (reactive gas) into the processing chamber 201. The ozone gas supply pipe 213o is provided with a valve vo3 that controls the supply of ozone gas into the processing chamber 201.

  The upstream end of the second oxygen gas supply pipe 212o is connected to the upstream side of the flow rate controller 221o of the first oxygen gas supply pipe 211o. The downstream end of the second oxygen gas supply pipe 212o is connected to the upstream side of the valve vo3 of the ozone gas supply pipe 213o. The second oxygen gas supply pipe 212o is provided with a flow rate controller (MFC) 222o as a flow rate controller for controlling the supply flow rate of oxygen gas.

  With the above configuration, it is possible to supply ozone gas into the processing chamber 201 by supplying oxygen gas to the ozonizer 229o to generate ozone gas and opening the valve vo3. Note that if the oxygen gas is supplied from the second oxygen gas supply pipe 212o during the supply of the ozone gas into the processing chamber 201, the ozone gas supplied into the processing chamber 201 is diluted with the oxygen gas to obtain an ozone gas concentration. Can be adjusted. Mainly, an oxygen gas supply source 230o, a first oxygen gas supply pipe 211o, an ozonizer 229o, a flow rate controller 221o, an ozone gas supply pipe 213o, a valve vo3, a second oxygen gas supply pipe 212o, and a flow rate controller 222o are used to supply an oxidant (oxidation). Agent supply line).

(Purge gas supply system)
Further, at the outside of the processing chamber 201, _{N 2} gas supply source 230p supplying _{N 2} gas as a purge gas is provided. The upstream end of the purge gas supply pipe 214 is connected to the N ₂ gas supply source 230p. The downstream end of the purge gas supply pipe 214 branches into three lines, that is, a first purge gas supply pipe 214h, a second purge gas supply pipe 214a, and a third purge gas supply pipe 214o. The downstream end portions of the first purge gas supply pipe 214h, the second purge gas supply pipe 214a, and the third purge gas supply pipe 214o are valves vh3 of the first source gas supply pipe 213h, the second source gas supply pipe 213a, and the ozone gas supply pipe 213o. , Va3
, Vo3, respectively. The first purge gas supply pipe 214h, the second purge gas supply pipe 214a, and the third purge gas supply pipe 214o include flow rate controllers (MFC) 224h, 224a, and 224o as flow rate controllers for controlling the supply flow rate of N ₂ gas. , Valves vh4, va4, vo4 for controlling the supply of N ₂ gas are provided, respectively. Mainly, N ₂ gas supply source 230p, purge gas supply pipe 214, first purge gas supply pipe 214h, second purge gas supply pipe 214a, third purge gas supply pipe 214o, flow rate controllers 224h, 224a, 224o, valves vh4, va4, vo4. Thus, a purge gas supply system (purge gas supply line) is configured.

(Vent system)
Further, a first vent pipe 215h, a second vent pipe 215a, and a third vent are provided upstream of the valves vh3, va3, and vo3 of the first source gas supply pipe 213h, the second source gas supply pipe 213a, and the ozone gas supply pipe 213o. The upstream ends of the pipes 215o are connected to each other. In addition, the downstream end portions of the first vent pipe 215h, the second vent pipe 215a, and the third vent pipe 215o are unified so as to be merged into a vent pipe 215. The vent pipe 215 is a raw material recovery trap 263 of the exhaust pipe 261. It is connected to the upstream side. The first vent pipe 215h, the second vent pipe 215a, and the third vent pipe 215o are provided with valves vh5, va5, and vo5 for controlling gas supply, respectively.

  With the above configuration, by closing the valves vh3, va3, vo3 and opening the valves vh5, va5, vo5, the gas flowing in the first source gas supply pipe 213h, the second source gas supply pipe 213a, and the ozone gas supply pipe 213o The processing chamber 201 can be bypassed without being supplied into the processing chamber 201, and exhausted out of the processing chamber 201.

  Further, upstream of the valves vh4, va4, vo4 of the first purge gas supply pipe 214h, the second purge gas supply pipe 214a, and the third purge gas supply pipe 214o and downstream of the flow rate controllers 224h, 224a, 224o, The fourth vent pipe 216h, the fifth vent pipe 216a, and the sixth vent pipe 216o are connected to each other. Further, the downstream end portions of the fourth vent pipe 216h, the fifth vent pipe 216a, and the sixth vent pipe 216o are unified so as to be a vent pipe 216. The vent pipe 216 is connected downstream of the raw material recovery trap 263 in the exhaust pipe 261 and upstream of the vacuum pump 264. The fourth vent pipe 216h, the fifth vent pipe 216a, and the sixth vent pipe 216o are provided with valves vh6, va6, and vo6 for controlling gas supply, respectively.

With the above configuration, N ₂ gas flowing in the first purge gas supply pipe 214h, the second purge gas supply pipe 214a, and the third purge gas supply pipe 214o by closing the valves vh4, va4, vo4 and opening the valves vh6, va6, vo6. Without being supplied into the processing chamber 201, the processing chamber 201 can be bypassed and exhausted out of the processing chamber 201. By closing the valves vh3, va3, vo3 and opening the valves vh5, va5, vo5, the gas flowing in the first source gas supply pipe 213h, the second source gas supply pipe 213a, and the ozone gas supply pipe 213o When the processing chamber 201 is bypassed without being supplied into the 201 and exhausted to the outside of the processing chamber 201, the first source gas supply pipe 213h and the second source gas are opened by opening the valves vh4, va4, and vo4. N ₂ gas is introduced into the supply pipe 213a and the ozone gas supply pipe 213o, and the inside of each raw material gas supply pipe is purged. Further, the valves vh6, va6, vo6 are set so as to perform the reverse operation of the valves vh4, va4, vo4, and when the N ₂ gas is not supplied into each source gas supply pipe, the processing chamber 201 is bypassed. N ₂ gas is exhausted. Mainly, the first vent pipe 215h, second vent pipe 215a, third vent pipe 215o, vent pipe 215, fourth vent pipe 216h, fifth vent pipe 216a, sixth vent pipe 216o, vent pipe 216, valve vh5 A vent system (vent line) is constituted by va5, vo5 and valves vh6, va6, vo6.

(controller)
Note that the substrate processing apparatus according to the present embodiment includes a controller 280 that controls the operation of each unit of the substrate processing apparatus. The controller 280 includes a gate valve 251, an elevating mechanism 207b, a transfer robot 273, a heater 206, a pressure regulator (APC) 262, a vaporizer 229h and 229a, an ozonizer 229o, a vacuum pump 264, valves vh1 to vh6, va1 to va6, and vo3. ˜vo6, liquid flow rate controllers 221h and 221a, flow rate controllers 225h, 225a, 224h, 224a, 221o, 222o, 224o and the like are controlled.

(2) Substrate Processing Step Next, as a step of manufacturing the semiconductor device (device) according to the embodiment of the present invention, a substrate processing step of forming a thin film on a wafer using the above-described substrate processing apparatus will be described. 2 and will be described with reference to FIG. FIG. 2 is a flowchart of a substrate processing process according to an embodiment of the present invention. Further, FIG. 5 illustrates the first raw material supply in the ALD saturation mode, the oxidant supply, the second raw material supply in the ALD saturation mode, and the oxidant supply alternately performed a predetermined number of times according to an embodiment of the present invention. It is a sequence diagram as a timing chart which illustrates the timing of supply of. In the present embodiment, two or more kinds of raw materials having greatly different film formation rates, that is, an Hf raw material is used as the first raw material (first liquid raw material), an Al raw material is used as the second raw material (second liquid raw material), An example of forming a hafnium aluminate (HfAlO) film as a third metal oxide film having a desired composition, for example, a composition in the range of HfO: AlO = 100: 1 to 10: 1, using ozone gas as an oxidant. Will be described. That is, of the plurality of metal elements (Hf, Al) constituting the HfAlO film, the first metal element having the largest composition ratio is Hf, and the first metal oxide film containing the first metal element is HfO. A second metal element having a composition ratio smaller than that (Hf) is Al, and a second metal oxide film containing the second metal element is an AlO film. In the following description, the operation of each part constituting the substrate processing apparatus is controlled by the controller 280.

(Substrate loading step (S1), Substrate placing step (S2))
First, the elevating mechanism 207b is operated to lower the support table 203 to the wafer transfer position shown in FIG. Then, the gate valve 251 is opened to allow the processing chamber 201 and the transfer chamber 271 to communicate with each other. Then, the wafer 200 to be processed is loaded from the transfer chamber 271 into the processing chamber 201 by the transfer robot 273 while being supported by the transfer arm 273a (S1). The wafer 200 carried into the processing chamber 201 is temporarily placed on lift pins 208b protruding from the upper surface of the susceptor 217. When the transfer arm 273a of the transfer robot 273 returns from the processing chamber 201 to the transfer chamber 271, the gate valve 251 is closed.

  Subsequently, the elevating mechanism 207b is operated to raise the support table 203 to the wafer processing position shown in FIG. As a result, the lift pins 208b are buried from the upper surface of the susceptor 217, and the wafer 200 is placed on the susceptor 217 (S2).

(Pressure adjustment step (S3), temperature rise step (S4))
Subsequently, the pressure regulator (APC) 262 controls the pressure in the processing chamber 201 to be a predetermined processing pressure (S3). Further, the power supplied to the heater 206 is adjusted, the temperature of the wafer 200 is increased, and control is performed so that the surface temperature of the wafer 200 becomes a predetermined processing temperature (S4).

In the substrate loading step (S1), the substrate placing step (S2), the pressure adjusting step (S3), the temperature raising step (S4), and the substrate unloading step (S15) described later, the vacuum pump 264 is operated. Meanwhile, the valves vh3, va3, and vo3 are closed and the valves vh4, va4, and vo4 are opened, so that the N ₂ gas always flows into the processing chamber 201. Thereby, adhesion of particles on the wafer 200 can be suppressed. The vacuum pump 264 is always operated at least from the substrate loading step (S1) to the substrate unloading step (S15) described later.

In parallel with the steps S1 to S4, a first source gas (Hf source gas) obtained by vaporizing the first liquid source (Hf source) is generated (preliminarily vaporized). That is, while the valve vh3 is closed, the valve vh2 is opened and the carrier gas is supplied to the carburetor 229h, the valve vh1 is opened, and the pressurized gas is supplied from the pressurized gas supply pipe 237h. The first liquid source is pumped (supplied) to the vaporizer 229h, and the first liquid source is vaporized in the vaporizer 229h to generate the first source gas. In this preliminary vaporization step, while the vacuum pump 264 is operated and the valve vh3 is closed, the valve vh5 is opened to bypass the process chamber 201 and supply the first source gas into the process chamber 201. Keep it. In the present embodiment, for example, Hf (MMP) ₄ is used as the first liquid source (Hf source).

At this time, a second raw material gas (Al raw material gas) obtained by vaporizing the second liquid raw material (Al raw material) is also generated (preliminarily vaporized). That is, while the valve va3 is closed, the valve va2 is opened and the carrier gas is supplied to the vaporizer 229a, the valve va1 is opened, and the pressurized gas is supplied from the pressurized gas supply pipe 237a. The second liquid source is pumped (supplied) to the vaporizer 229a, and the second liquid source is vaporized by the vaporizer 229a to generate a second source gas. In this preliminary vaporization step, while the vacuum pump 264 is operated, the valve va5 is opened while the valve va3 is closed, thereby bypassing the processing chamber 201 and exhausting it without supplying the second source gas into the processing chamber 201. Keep it. In the present embodiment, for example, Al (MMP) ₃ is used as the second liquid source (Al source).

  Further, at this time, it is preferable to generate ozone gas as an oxidizing agent (reactive gas). That is, oxygen gas is supplied from the oxygen gas supply source 230o to the ozonizer 229o, and ozone gas is generated in the ozonizer 229o. At this time, while operating the vacuum pump 264, the valve vo5 is opened while the valve vo3 is closed, thereby bypassing and exhausting the processing chamber 201 without supplying ozone gas into the processing chamber 201.

  It takes a predetermined time for the vaporizers 229h and 229a to generate the first source gas and the second source gas in a stable state, or to generate the ozone gas in a stable state using the ozonizer 229o. That is, the raw material gas and the ozone gas are supplied in an unstable state at the initial generation of the raw material gas and the ozone gas. For this reason, in this embodiment, the first source gas, the second source gas, and the ozone gas are generated in advance so that they can be stably supplied, and the valves vh3, vh5, va3, va5, vo3, and vo5 are opened and closed. By switching, the flow paths of the first source gas, the second source gas, and the ozone gas are switched. As a result, it is possible to quickly start or stop the stable supply of the first source gas, the second source gas, and the ozone gas into the processing chamber 201 by switching the valve, which is preferable.

<HfAlO film formation process>
(First raw material supply step (S5))
Subsequently, the valves vh4 and vh5 are closed, the valve vh3 is opened, and the supply of the first source gas into the processing chamber 201 is started. The first source gas is dispersed by the shower head 240 and is uniformly supplied onto the wafer 200 in the processing chamber 201. Excess first source gas flows through the exhaust duct 259 and is exhausted to the exhaust port 260. Note that when the first source gas is supplied into the processing chamber 201, the first source gas is prevented from entering the second source gas supply pipe 213a and the ozone gas supply pipe 213o. It is preferable to keep the valves va4 and vo4 open so as to promote the diffusion of the first source gas, and to always allow the N ₂ gas to flow into the processing chamber 201.

  When a predetermined time has elapsed after opening the valve vh3 and starting the supply of the first source gas, the valve vh3 is closed and the valves vh4 and vh5 are opened to stop the supply of the first source gas into the processing chamber 201. . At the same time, the valve vh1 is closed and the supply of the first liquid raw material to the vaporizer 229h is also stopped.

(Purge process (S6))
After the valve vh3 is closed and the supply of the first source gas into the processing chamber 201 is stopped, the valves vh4, va4, and vo4 are kept open, and the supply of N ₂ gas into the processing chamber 201 is continued. Do. The N ₂ gas is supplied into the processing chamber 201 through the shower head 240, flows in the exhaust duct 259, and is exhausted to the exhaust port 260. In this way, the inside of the processing chamber 201 is purged with N ₂ gas, and the first source gas remaining in the processing chamber 201 is removed.

(Oxidant supply step (S7))
When the purge in the processing chamber 201 is completed, the valves vo4 and vo5 are closed, the valve vo3 is opened, and supply of ozone gas as an oxidant into the processing chamber 201 is started. The ozone gas is dispersed by the shower head 240 and is uniformly supplied onto the wafer 200 in the processing chamber 201. Excess ozone gas and reaction byproducts flow through the exhaust duct 259 and are exhausted to the exhaust port 260. When ozone gas is supplied into the processing chamber 201, the ozone gas is prevented from entering the first source gas supply pipe 213h and the second source gas supply pipe 213a, and the ozone gas is diffused in the processing chamber 201. It is preferable to keep the valves vh4 and va4 open so that N ₂ gas always flows into the processing chamber 201.

  When a predetermined time has elapsed after opening the valve vo3 and starting the supply of ozone gas, the valve vo3 is closed, the valves vo4 and vo5 are opened, and the supply of the ozone gas into the processing chamber 201 is stopped.

(Purge process (S8))
After the valve vo3 is closed and the supply of ozone gas into the processing chamber 201 is stopped, the valves vh4, va4, and vo4 are kept open, and the supply of N ₂ gas into the processing chamber 201 is continued. The N ₂ gas is supplied into the processing chamber 201 through the shower head 240, flows in the exhaust duct 259, and is exhausted to the exhaust port 260. In this manner, the inside of the processing chamber 201 is purged with N ₂ gas, and ozone gas and reaction byproducts remaining in the processing chamber 201 are removed.

(Cycle step (S9))
Then, the steps S5 to S8 are set as one cycle, and this cycle is performed for a predetermined cycle, for example, one cycle, thereby forming a hafnium oxide (HfO) film as a first metal oxide film on the wafer 200.

At this time, the temperature of the wafer 200 is controlled to be a predetermined processing temperature, for example, 140 to 450 ° C., preferably 200 to 300 ° C. by the heater 206, and the pressure in the processing chamber 201 is predetermined by the pressure regulator 262. For example, 50 to 800 Pa, preferably 100 to 800 Pa. Further, the supply flow rate of Hf (MMP) ₄ as the first liquid source is controlled to be a predetermined supply flow rate, for example, 0.01 to 0.2 g / min by the liquid flow rate controller 221h. The supply flow rate of the _three gases is controlled by the flow rate controller 221o so as to be a predetermined supply flow rate, for example, 200 to 5000 sccm.

  At this time, the thickness of the HfO film formed per HfO film formation step is set to a thickness according to the composition of the HfAlO film. For example, in order to set the composition of the HfAlO film within the range of HfO: AlO = 100: 1 to 10: 1, the film thickness of the HfO film formed per HfO film formation step (steps S5 to S9) is set to The thickness of the AlO film formed per time is set to 0.1 mm.

(Second raw material supply step (S10))
Subsequently, the valves va4 and va5 are closed, the valve va3 is opened, and the supply of the second source gas into the processing chamber 201 is started. The second source gas is dispersed by the shower head 240 and is uniformly supplied onto the wafer 200 in the processing chamber 201. Excess second source gas flows in the exhaust duct 259 and is exhausted to the exhaust port 260. When supplying the second source gas into the processing chamber 201, the second source gas is prevented from entering the first source gas supply pipe 213h and the ozone gas supply pipe 213o. It is preferable to keep the valves vh4 and vo4 open so as to promote the diffusion of the second source gas, and to always allow the N ₂ gas to flow into the processing chamber 201.

  After the valve va3 is opened and the supply of the second source gas is started, when a predetermined time has elapsed, the valve va3 is closed, the valves va4 and va5 are opened, and the supply of the first source gas into the processing chamber 201 is stopped. . At the same time, the valve va1 is closed and the supply of the second liquid raw material to the vaporizer 229a is also stopped.

(Purge process (S11))
After the valve va3 is closed and the supply of the second source gas into the processing chamber 201 is stopped, the valves vh4, va4, and vo4 are kept open and the supply of N ₂ gas into the processing chamber 201 is continued. Do. The N ₂ gas is supplied into the processing chamber 201 through the shower head 240, flows in the exhaust duct 259, and is exhausted to the exhaust port 260. In this way, the inside of the processing chamber 201 is purged with N ₂ gas, and the second source gas remaining in the processing chamber 201 is removed.

(Oxidant supply step (S12))
When the purge in the processing chamber 201 is completed, the valves vo4 and vo5 are closed, the valve vo3 is opened, and supply of ozone gas as an oxidant into the processing chamber 201 is started. The ozone gas is dispersed by the shower head 240 and is uniformly supplied onto the wafer 200 in the processing chamber 201. Excess ozone gas and reaction byproducts flow through the exhaust duct 259 and are exhausted to the exhaust port 260. When ozone gas is supplied into the processing chamber 201, the ozone gas is prevented from entering the first source gas supply pipe 213h and the second source gas supply pipe 213a, and the ozone gas is diffused in the processing chamber 201. It is preferable to keep the valves vh4 and va4 open so that N ₂ gas always flows into the processing chamber 201.

  When a predetermined time has elapsed after opening the valve vo3 and starting the supply of ozone gas, the valve vo3 is closed, the valves vo4 and vo5 are opened, and the supply of the ozone gas into the processing chamber 201 is stopped.

(Purge process (S13))
After the valve vo3 is closed and the supply of ozone gas into the processing chamber 201 is stopped, the valves vh4, va4, and vo4 are kept open, and the supply of N ₂ gas into the processing chamber 201 is continued. The N ₂ gas is supplied into the processing chamber 201 through the shower head 240, flows in the exhaust duct 259, and is exhausted to the exhaust port 260. In this manner, the inside of the processing chamber 201 is purged with N ₂ gas, and ozone gas and reaction byproducts remaining in the processing chamber 201 are removed.

  Then, the steps S10 to S13 are set as one cycle, and this cycle is performed for one cycle, whereby an aluminum oxide (AlO) film as a second metal oxide film is formed on the hafnium oxide (HfO) film formed on the wafer 200. Form.

(Cycle step (S14))
Then, the steps S5 to S13 are set as one cycle, and this cycle is performed for a predetermined cycle, for example, one cycle, thereby forming a stacked structure of the HfO film and the AlO film on the wafer 200. That is, the HfO film forming process (steps S5 to S9) and the AlO film forming process (S10 to S13) are alternately performed a predetermined number of times, for example, once each, thereby forming a laminated structure of the HfO film and the AlO film on the wafer 200. Form. Then, Hf and Al diffuse between the HfO film and the AlO film during the film formation, so that a hafnium aluminate (HfAlO) film as a third metal oxide film is formed on the wafer 200. .

At this time, the temperature of the wafer 200 is controlled to be a predetermined processing temperature, for example, 140 to 450 ° C., preferably 200 to 300 ° C. by the heater 206, and the pressure in the processing chamber 201 is predetermined by the pressure regulator 262. For example, 50 to 800 Pa, preferably 100 to 800 Pa. That is, in the present embodiment, the temperature of the wafer 200 and the pressure in the processing chamber 201 in the AlO film forming process are controlled to be the same as the temperature of the wafer 200 and the pressure in the processing chamber 201 in the HfO film forming process, respectively. is doing. When priority is given to increasing the controllability of Al composition control (control that suppresses the amount of Al added to Hf to a small amount, for example, 10% or less), the temperature of the wafer 200 depends on the deposition rate of the AlO film. It is good to set it as the low temperature side which becomes low, for example, 140-200 degreeC. It is possible to change the temperature of the wafer 200 between the HfO film forming step and the AlO film forming step. In this case, considering that priority is given to controlling the trace composition of Al, the wafer temperature in the AlO film forming step is It is good to set it as 140-300 degreeC, Preferably it is 140-200 degreeC. Note that the pressure in the processing chamber 201 can also be changed between the HfO film forming step and the AlO film forming step. The supply flow rate of Al (MMP) ₃ as the second liquid source is controlled to be a predetermined supply flow rate, for example, 0.01 to 0.2 g / min by the liquid flow rate controller 221a, and O as the oxidant. The supply flow rate of the _three gases is controlled by the flow rate controller 221o so as to be a predetermined supply flow rate, for example, 200 to 5000 sccm.

  At this time, the film thickness of the AlO film formed per AlO film forming process is a film thickness according to the composition of the HfAlO film with reference to the film thickness of the HfO film formed per HfO film forming process. And For example, in order to set the composition of the HfAlO film within the range of HfO: AlO = 100: 1 to 10: 1, the film thickness of the HfO film formed per HfO film formation process is set to 1 to 10 mm, and AlO The film thickness of the AlO film formed per film forming step is 0.1 mm.

  In parallel with the AlO film forming step, the first source gas is generated (preliminary vaporization). In parallel with the next HfO film forming step, the second source gas is generated (preliminary vaporization).

As described above, the hafnium aluminate (HfAlO) film is formed on the wafer 200 by alternately performing the HfO film forming process from steps S5 to S9 and the AlO film forming process from steps S10 to S13 a predetermined number of times. To do. At this time, by controlling the film thickness of the HfO film formed per HfO film forming process and the film thickness of the AlO film formed per AlO film forming process, a plurality of HfAlO films are formed. The composition ratio of the metal element (Hf, Al) is freely controlled. In addition, by using two or more kinds of raw materials having greatly different film formation rates, the film thickness of the HfO film formed per HfO film formation process and the film thickness of the AlO film formed per AlO film formation process. And make a big difference. As a result, among the plurality of elements (Hf, Al) constituting the HfAlO film, a small amount composition control is performed so as to reduce the ratio of Al to Hf within, for example, several percent. Further, the composition of the HfAlO film can be made uniform both in the film thickness direction (depth direction) and in the wafer 200 in-plane direction.

(Substrate unloading step (S15))
Thereafter, the wafer 200 after the HfAlO film having a desired film thickness and composition is formed from the inside of the processing chamber 201 by a procedure reverse to the procedure shown in the substrate loading step (S1) and the substrate placing step (S2). It is carried out into the transfer chamber 271 and the substrate processing process according to this embodiment is completed. After that, annealing (heat treatment) is performed on the HfAlO film formed on the wafer 200, so that the mutual diffusion of Hf and Al between the HfO film and the AlO film is further promoted, and the composition of the HfAlO film is increased. Is more uniform both in the film thickness direction and in the wafer in-plane direction.

  Note that the HfO film forming step is performed in a CVD mode or an ALD saturation mode.

  When the HfO film forming process is performed in the CVD mode, the processing temperature (the temperature of the wafer 200) is controlled to a temperature at which the first source gas is self-decomposed, for example, 300 ° C. In this case, in the first raw material supply step (S5), the first raw material gas is self-decomposed, and an HfO film, which is a film containing about 1 to 5% Hf, is formed (deposited) on the wafer 200. In the oxidant supply step (S7), impurities such as C and H are removed from the HfO film of about 1 to 5 mm formed on the wafer 200 by ozone gas.

  When performing the HfO film formation step in the CVD mode, by performing one cycle of the above-described steps S5 to S8 and controlling the supply time of the first source gas in the first source supply step (S5), The film thickness of the HfO film to be formed can be adjusted. In the CVD mode, since a relatively high film formation rate can be obtained, the time required for the HfO film formation process can be shortened, and the productivity of the substrate processing can be improved. Note that the film thickness (deposition rate) of the HfO film formed per HfO film formation step is not limited to the supply time of the first source gas, but also the supply flow rate of the first source gas, the temperature of the wafer 200, and the processing. It is also possible to adjust by changing the pressure in the chamber 201 (partial pressure of the first source gas) or the like.

  When the HfO film forming process is performed in the ALD saturation mode, the processing temperature (the temperature of the wafer 200) is controlled to a temperature at which the first source gas does not self-decompose, for example, 200 ° C. In this case, the first source gas molecules are adsorbed on the wafer 200 in the first source supply step (S5). At this time, the first source gas is supplied until the adsorption amount of the first source gas molecules is saturated. This is shown in FIG. As shown in FIG. 6, in the first raw material supply step (S5), the adsorption amount of the first raw material gas molecules on the wafer 200 is saturated and the self-limit is effective (the first raw material gas molecules are further absorbed). The supply of the first source gas has been stopped since it has become impossible to do so. Thereafter, in the oxidant supply step (S7), the first source gas molecules adsorbed on the wafer 200 react with ozone gas, so that an HfO film having a saturation film thickness of about 1 mm on the wafer 200 is obtained. Is formed. At this time, impurities such as C and H to be mixed into the HfO film are desorbed by the ozone gas.

When the HfO film formation step is performed in the ALD saturation mode, an extremely thin HfO film can be formed by utilizing the phenomenon that the adsorption of the first source gas molecules on the wafer 200 is saturated. Further, as described above, since the supply of the first source gas is stopped after the adsorption amount of the first source gas molecules on the wafer 200 is saturated, the wafer at the end of the first source supply step (S5). It is possible to stabilize the amount of the first source gas molecules adsorbed on 200 and to stabilize the film thickness of the HfO film formed per cycle. And it becomes possible to adjust the film thickness of the HfO film | membrane formed with sufficient reproducibility by controlling the cycle number of the cycle comprised by the above-mentioned process S5-S8. For example, the film thickness of the HfO film can be improved with good reproducibility by performing the above-described cycle for 3 cycles, for example, 3 mm (= 1 cm / cycle × 3 cycles). The film thickness can be set to, for example, 4 mm (= 1 cm / cycle × 4 cycles) with good reproducibility.

  The AlO film forming step is performed in the ALD saturation mode.

  When the AlO film forming process is performed in the ALD saturation mode, the processing temperature (the temperature of the wafer 200) is controlled to a temperature at which the second source gas does not self-decompose, for example, 200 ° C. In this case, the second source gas molecules are adsorbed on the wafer 200 in the second source supply step (S10). At this time, the second source gas is supplied until the adsorption amount of the second source gas molecules is saturated. This is shown in FIG. As shown in FIG. 6, in the second raw material supply step (S10), the amount of adsorption of the second raw material gas molecules on the wafer 200 is saturated and the self-limit is effective (the second raw material gas molecules are further adsorbed). The supply of the second raw material gas has been stopped since it has become impossible to do so. After that, in the oxidant supply step (S12), the second raw material adsorbed on the wafer 200 reacts with ozone gas, so that AlO on the wafer 200 has an ALD saturation mode saturated film thickness of, for example, about 0.1 mm. A film is formed. At this time, impurities such as C and H to be mixed into the AlO film are desorbed by the ozone gas.

  When the AlO film forming step is performed in the ALD saturation mode, an extremely thin AlO film can be formed as described above. In addition, the thickness of the AlO film formed per cycle can be stabilized. In this embodiment, the example in which the cycle composed of the above-described steps S10 to S13 is performed only once has been described. However, the number of cycles in this cycle can also be controlled, thereby forming the cycle. It becomes possible to adjust the thickness of the AlO film with good reproducibility.

(3) Effects According to this Embodiment According to this embodiment, one or more effects described below are exhibited.

  According to this embodiment, a hafnium aluminate (HfAlO) film having a desired film thickness is formed by alternately performing the HfO film forming process and the AlO film forming process a predetermined number of times. Thereby, the controllability of the composition ratio of the HfAlO film can be improved. That is, by adjusting the thickness of the HfO film formed per HfO film formation process and the thickness of the AlO film formed per AlO film formation process, a plurality of metals constituting the HfAlO film is adjusted. It becomes possible to freely control the composition ratio of the elements (Hf, Al). The film thickness of the HfO film formed per HfO film forming process can be controlled by adjusting the number of times this cycle is performed with the above-described steps S5 to S8 as one cycle. The thickness of the AlO film formed per AlO film forming step can be controlled by adjusting the number of times this cycle is performed with the above-described steps S10 to S13 as one cycle.

According to the present embodiment, by using two or more kinds of raw materials having greatly different film formation rates, an HfO film formed per HfO film formation process and an AlO film formed per AlO film formation process are formed. By making the film thickness greatly different, it is possible to perform a trace composition control that reduces the ratio of Al to Hf, for example, within several percent of the plurality of elements (Hf, Al) constituting the HfAlO film. It becomes possible. For example, by using Hf (MMP) ₄ as the first liquid source (Hf source) and Al (MMP) ₃ as the second liquid source (Al source), the HfO film to be formed per HfO film formation step is used. While controlling the film thickness to be, for example, 1.0 to 10.0 mm, the film thickness of the AlO film formed per AlO film forming step is controlled to be, for example, 0.1 mm. As a result, it is possible to perform a trace composition control that reduces the Al composition ratio to Hf in the HfAlO film, for example, to 1 to 10% (HfO: AlO = 10: 1 to 100: 1).

  According to the present embodiment, the uniformity of the composition of the HfAlO film can be improved both in the film thickness direction (depth direction) of the HfAlO film and in the in-plane direction of the wafer 200. For example, even in the case where the above-described trace composition control is performed, the thickness of the AlO film formed per AlO film forming process is reduced to 0.1 mm to form the HO film forming process once. The film thickness of the HfO film can be set to a thickness that does not prevent interdiffusion of Hf and Al between the stacked HfO film and the AlO film, for example, a thickness of 1.0 to 10 mm. Thereby, mutual diffusion of Hf and Al between the laminated HfO film and the AlO film can be promoted, and the uniformity of the composition of the HfAlO film can be improved even in the film thickness direction (depth direction) of the HfAlO film. It can also be improved in the in-plane direction of the wafer 200, respectively.

  According to this embodiment, the AlO film containing Al, which is the metal element having the smaller composition ratio among the plurality of metal elements (Hf, Al) constituting the HfAlO film, is formed in the ALD saturation mode. In the ALD saturation mode, an extremely thin (for example, about 0.1 mm) AlO film can be formed by utilizing the phenomenon that the adsorption of the second source gas molecules on the wafer 200 is saturated. By making the thickness of the AlO film formed per AlO film forming process extremely thin, the above-described trace composition control can be easily realized. Further, since the supply of the second source gas is stopped after the adsorption amount of the second source gas on the wafer 200 is saturated, the second source material on the wafer 200 at the end of the second source gas supply step (S10). The amount of gas adsorption can be stabilized, and the film thickness of the AlO film formed per cycle can be stabilized. And it becomes possible to adjust the film thickness of the AlO film | membrane formed with sufficient reproducibility by controlling the cycle number of the cycle comprised by the above-mentioned process S10-S13. Then, the composition of the HfAlO film can be stabilized and the quality of the substrate processing can be improved.

  According to the present embodiment, the HfO film containing Hf, which is the metal element having the larger composition ratio among the plurality of metal elements (Hf, Al) constituting the HfAlO film, is formed in the CVD mode or the ALD saturation mode. . When the HfO film forming process is performed in the CVD mode, a relatively large film forming speed can be obtained, so that the time required for the HfO film forming process can be shortened and the substrate processing productivity can be improved. Further, when the HfO film forming process is performed in the ALD saturation mode, as described above, the supply of the first source gas is stopped after the adsorption amount of the first source gas on the wafer 200 is saturated. The adsorption amount of the first source gas onto the wafer 200 at the end of the supplying step (S5) can be stabilized, and the film thickness of the HfO film formed per cycle can be stabilized. And it becomes possible to adjust the film thickness of the HfO film | membrane formed with sufficient reproducibility by controlling the cycle number of the cycle comprised by the above-mentioned process S5-S8. Then, the composition of the HfAlO film can be stabilized and the quality of the substrate processing can be improved.

  According to the present embodiment, the temperature of the wafer 200 in the HfO film forming process and the temperature of the wafer 200 in the AlO film forming process can be set to the same temperature. That is, a cycle step (S9) in which steps S5 to S8 are defined as one cycle and this cycle is performed for a predetermined cycle, and steps S10 to S13 can be performed at the same temperature (for example, 250 to 300 ° C.). In such a case, it is possible to avoid the occurrence of temperature adjustment time (waiting time) during the substrate processing and to improve the substrate processing productivity.

According to this embodiment, the pressure in the processing chamber 201 in the HfO film forming step and the pressure in the processing chamber 201 in the AlO film forming step can be set to the same pressure. That is, a cycle step (S9) in which steps S5 to S8 are defined as one cycle and this cycle is performed for a predetermined cycle, and steps S10 to S13 can be performed at the same pressure (for example, 100 to 800 Pa). In such a case, it is possible to avoid the occurrence of pressure adjustment time (waiting time) during the substrate processing and improve the productivity of the substrate processing.

  According to the present embodiment, in the oxidant supply step (S7), impurities such as C and H are removed from the HfO film formed in the CVD mode by ozone gas, or mixed in the HfO film formed in the ALD saturation mode. Impurities such as C and H to be eliminated can be eliminated. Further, in the oxidant supply step (S12), impurities such as C and H which are to be mixed into the AlO film formed in the ALD saturation mode can be desorbed by ozone gas. As a result, the film quality of the HfAlO film can be improved.

<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, the case where the first metal element is Hf and the second metal element is Al has been described. However, the present invention is not limited to the above-described embodiment. That is, the first metal element is Zr (zirconium), Ti (titanium), Al (aluminum), La (lanthanum), Si (silicon), Nb (niobium), Sr (strontium), Ba (barium), Ta ( Tantalum) or Y (yttrium), and the second metal element is Hf (hafnium), Zr (zirconium), Ti (titanium), Al (aluminum), La (lanthanum), Si (silicon), Nb (Niobium), Sr (strontium), Ba (barium), Ta (tantalum), and Y (yttrium) are also suitably applicable. For example, the present invention can also be suitably applied to a case where the first metal element is Zr, the second metal element is Al, and a ZrAlO (zirconium aluminate) film is formed as the third metal oxide film.

  In the above-described embodiment, the example of controlling the composition ratio of the metal oxide film composed of two kinds of metal elements has been described. However, the present invention describes the composition of the metal oxide film composed of three or more kinds of metal elements. It can also be applied when controlling the ratio.

  Moreover, although the above-mentioned embodiment demonstrated the example which forms into a film using the single-wafer | sheet-fed apparatus which processes one board | substrate at a time as a substrate processing apparatus, this invention is not limited to the above-mentioned embodiment. For example, the film may be formed using a batch type vertical apparatus that processes a plurality of substrates at a time as the substrate processing apparatus. Hereinafter, this vertical apparatus will be described.

  FIG. 12 is a schematic configuration diagram of a vertical processing furnace of a vertical apparatus preferably used in the present embodiment. FIG. 12A shows a processing furnace 302 portion in a vertical cross section, and FIG. 12B shows a processing furnace 302. The portion is shown by a cross-sectional view along the line AA in FIG.

  As shown in FIG. 12A, the processing furnace 302 has a heater 307 as a heating means (heating mechanism). The heater 307 has a cylindrical shape and is vertically installed by being supported by a heater base (not shown) as a holding plate.

Inside the heater 307, a process tube 303 as a reaction tube is disposed concentrically with the heater 307. The process tube 303 is made of a heat-resistant material such as quartz (SiO ₂ ) or silicon carbide (SiC), and has a cylindrical shape with the upper end closed and the lower end opened. A processing chamber 301 is formed in a cylindrical hollow portion of the process tube 303 so that wafers 200 as substrates can be accommodated in a state of being aligned in multiple stages in a vertical posture in a horizontal posture by a boat 317 described later.

A manifold 309 is disposed below the process tube 303 concentrically with the process tube 303. The manifold 309 is made of, for example, stainless steel and is formed in a cylindrical shape with an upper end and a lower end opened. The manifold 309 is engaged with the process tube 303 and is provided to support the process tube 303. An O-ring 320a as a seal member is provided between the manifold 309 and the process tube 303. Since the manifold 309 is supported by the heater base, the process tube 303 is vertically installed. A reaction vessel is formed by the process tube 303 and the manifold 309.

  A first nozzle 333 a as a first gas introduction part and a second nozzle 333 b as a second gas introduction part are connected to the manifold 309 so as to penetrate the side wall of the manifold 309. Each of the first nozzle 333a and the second nozzle 333b has an L shape having a horizontal portion and a vertical portion, the horizontal portion is connected to the manifold 309, and the vertical portion is between the inner wall of the process tube 303 and the wafer 200. It is provided in an arc-shaped space so as to rise from the lower part of the process tube 303 along the inner wall above the process tube 303 in the loading direction of the wafer 200. A first gas supply hole 348a and a second gas supply hole 348b, which are supply holes for supplying gas, are provided on the side surfaces of the vertical portions of the first nozzle 333a and the second nozzle 333b, respectively. The first gas supply hole 348a and the second gas supply hole 348b have the same opening area from the lower part to the upper part, and are provided at the same opening pitch.

  The gas supply system connected to the first nozzle 333a and the second nozzle 333b is the same as in the above-described embodiment. However, the present embodiment is different from the above-described embodiment in that the source gas supply pipe 213 is connected to the first nozzle 333a and the ozone gas supply pipe 213o is connected to the second nozzle 333b. That is, in this embodiment, source gas (first source gas, second source gas) and ozone gas are supplied by separate nozzles. In addition, you may make it supply each raw material gas with a separate nozzle.

  The manifold 309 is provided with an exhaust pipe 331 that exhausts the atmosphere in the processing chamber 301. A vacuum pump 346 as an evacuation device is connected to the exhaust pipe 331 through a pressure sensor 345 as a pressure detector and an APC (Auto Pressure Controller) valve 342 as a pressure regulator. By adjusting the APC valve 342 based on the detected pressure information, the processing chamber 301 is configured to be evacuated so that the pressure in the processing chamber 301 becomes a predetermined pressure (degree of vacuum). Note that the APC valve 342 is configured to open and close the valve to evacuate / stop evacuation in the processing chamber 301, and to adjust the valve opening to adjust the pressure in the processing chamber 301. Open / close valve.

  Below the manifold 309, a seal cap 319 is provided as a furnace port lid that can airtightly close the lower end opening of the manifold 309. The seal cap 319 is brought into contact with the lower end of the manifold 309 from the lower side in the vertical direction. The seal cap 319 is made of a metal such as stainless steel and is formed in a disk shape. On the upper surface of the seal cap 319, an O-ring 320b is provided as a seal member that contacts the lower end of the manifold 309. On the opposite side of the seal cap 319 from the processing chamber 301, a rotation mechanism 367 for rotating a boat 317 described later is installed. A rotation shaft 355 of the rotation mechanism 367 passes through the seal cap 319 and is connected to the boat 317, and is configured to rotate the wafer 200 by rotating the boat 317. The seal cap 319 is configured to be moved up and down in a vertical direction by a boat elevator 315 as an elevating mechanism disposed outside the process tube 303, and thereby the boat 317 is carried into and out of the processing chamber 301. It is possible.

The boat 317 as a substrate holder is made of a heat-resistant material such as quartz or silicon carbide, and is configured to hold a plurality of wafers 200 in a horizontal posture and in a state where the centers are aligned with each other and held in multiple stages. Yes. A heat insulating member 318 made of a heat resistant material such as quartz or silicon carbide is provided at the lower part of the boat 317 so that heat from the heater 307 is not easily transmitted to the seal cap 319 side. A temperature sensor 363 as a temperature detector is installed in the process tube 303, and the temperature in the processing chamber 301 is adjusted by adjusting the power supply to the heater 307 based on the temperature information detected by the temperature sensor 363. Is configured to have a predetermined temperature distribution. The temperature sensor 363 is provided along the inner wall of the process tube 303, similarly to the first nozzle 333a and the second nozzle 333b.

  A controller 380 as a control unit (control means) includes an APC valve 342, a heater 307, a temperature sensor 363, a vacuum pump 346, a rotation mechanism 367, a boat elevator 315, valves vh1 to vh6, va1 to va6, vo3 to vo6, and a liquid flow rate. Operations of the controllers 221h and 221a, flow rate controllers 224h, 224a, 221o, 222o, 224o, 225h, 225a and the like are controlled.

  Next, a substrate processing step of forming a thin film on the wafer 200 as one step of the semiconductor device manufacturing process using the processing furnace 302 of the vertical apparatus according to the above configuration will be described. In the following description, the operation of each part constituting the vertical apparatus is controlled by the controller 380.

  A plurality of wafers 200 are loaded into the boat 317 (wafer charge). Then, as shown in FIG. 12A, the boat 317 holding the plurality of wafers 200 is lifted by the boat elevator 315 and loaded into the processing chamber 301 (boat loading). In this state, the seal cap 319 is in a state of sealing the lower end of the manifold 309 via the O-ring 320b.

  The inside of the processing chamber 301 is evacuated by a vacuum pump 346 so that the inside of the processing chamber 301 has a desired pressure (degree of vacuum). At this time, the pressure in the processing chamber 301 is measured by the pressure sensor 345, and the APC valve 342 is feedback-controlled based on the measured pressure. In addition, heating is performed by the heater 307 so that the inside of the processing chamber 301 has a desired temperature. At this time, feedback control of the power supply to the heater 307 is performed based on the temperature information detected by the temperature sensor 363 so that the inside of the processing chamber 301 has a desired temperature distribution. Then, the wafer 200 is rotated by rotating the boat 317 by the rotation mechanism 367.

  After that, for example, similarly to the above-described embodiment, by performing the step (S14) of alternately performing the HfO film forming step from steps S5 to S9 and the AlO film forming step from steps S10 to S13 a predetermined number of times. Then, a hafnium aluminate (HfAlO) film having a desired film thickness is formed on the wafer 200.

  Thereafter, the seal cap 319 is lowered by the boat elevator 315 to open the lower end of the manifold 309, and the wafer 200 after the HfAlO film having a desired film thickness is formed is held in the boat 317 in the state of the manifold 309. Unload from the lower end of the process tube 303 (boat unload). Thereafter, the processed wafer 200 is taken out from the boat 317 (wafer discharge).

  Examples of the present invention will be described below.

(HfO film formation by CVD mode)
First, Hf raw material introduction into the processing chamber containing the wafer → Hf raw material purge → oxidant introduction → oxidant purge was made one cycle, and this cycle was performed once or more to form an HfO film on the wafer. FIG. 9 shows the relationship between the Hf raw material supply time per cycle and the film thickness (deposition rate) of the HfO film formed per cycle. The horizontal axis in FIG. 9 indicates the Hf raw material supply time (sec) per cycle, and the vertical axis indicates the film thickness (Å / Cycle) of the HfO film formed per cycle. As the film forming conditions, the wafer temperature in each step is 450 ° C., the pressure in the processing chamber in each step is 100 Pa, Hf (MMP) ₄ is used as the Hf raw material, O ₃ is used as the oxidizing agent, and Hf (MMP) ₄ is used. The supply flow rate of 0.05 g / min, the supply flow rate of O ₃ gas was 2000 sccm, and the supply time of the Hf raw material was changed in the range of 14 to 30 seconds.

From this figure, when the wafer temperature is 450 ° C., if the Hf raw material supply time per cycle is 14 seconds, the film thickness of the HfO film formed per cycle is about 7.27 mm. If the Hf raw material supply time is 30 seconds, the film thickness of the HfO film formed per cycle is about 10.5 mm. Thus, in the film formation using Hf (MMP) ₄ at a wafer temperature of 450 ° C., the film thickness of the HfO film formed per cycle changes with the passage of the supply time of the Hf raw material. It turns out that it is CVD mode. It can be seen that at a wafer temperature of 450 ° C., the film thickness of the HfO film formed per cycle can be controlled in the range of at least 7.27 to 10.5 mm depending on the Hf raw material supply time per cycle.

(HfO film formation by ALD saturation mode)
Next, the wafer temperature and the pressure in the processing chamber are lowered, and Hf source introduction into the processing chamber containing the wafer → Hf source purge → oxidant introduction → oxidant purge is set as one cycle, and this cycle is performed once or more. Thus, an HfO film was formed on the wafer. FIG. 10 shows the relationship between the Hf raw material supply time per cycle and the film thickness of the HfO film formed per cycle. The horizontal axis in FIG. 10 indicates the Hf raw material supply time (sec) per cycle, and the vertical axis indicates the film thickness (Å / Cycle) of the HfO film formed per cycle. As the film forming conditions, the wafer temperature in each step is 250 ° C., the pressure in the processing chamber in each step is 100 Pa, Hf (MMP) ₄ is used as the Hf raw material, O ₃ gas is used as the oxidizing agent, and Hf (MMP) The supply flow rate of No. ₄ was 0.05 g / min, the supply flow rate of O ₃ gas was 2000 sccm, and the supply time of the Hf raw material was changed in the range of 2 to 30 seconds.

From this figure, when the wafer temperature is 250 ° C. and the processing chamber pressure is 100 Pa, the film thickness of the HfO film formed per cycle is always 1. It can be seen that it stabilizes to about 1 mm. Since the film thickness of the HfO film formed per cycle is constant regardless of the supply time of the Hf material, the film formation using Hf (MMP) ₄ at a wafer temperature of 250 ° C. and a processing chamber pressure of 100 Pa is performed. It can be seen that this is not the CVD mode but the ALD saturation mode. And it is possible to adjust the film thickness of the HfO film with good reproducibility by adjusting the number of executions of a cycle in which Hf raw material introduction → Hf raw material purge → oxidant introduction → oxidant purge is one cycle. I understand.

(AlO film formation by ALD saturation mode)
Al source film introduction into the processing chamber containing the wafer → Al source purge → oxidant introduction → oxidant purge was made one cycle, and this cycle was performed once or more to form an AlO film on the wafer. FIG. 11 shows the relationship between the number of cycles and the cumulative film thickness of the AlO film formed at that time. The horizontal axis in FIG. 11 indicates the number of cycles of the AlO film forming step, and the vertical axis indicates the accumulated film thickness (Å) of the AlO film. As film formation conditions, the wafer temperature in each step is 140 ° C., the processing chamber pressure in each step is 100 Pa, Al (MMP) ₃ is used as the Al source, O ₃ gas is used as the oxidizing agent, and Al (MMP) The supply flow rate of ₃ is 0.05 g / mi
n, the supply flow rate of O ₃ gas was 500 sccm, and the number of cycles of the Al raw material was changed in the range of 5 to 40 cycles.

  According to FIG. 11, the cumulative thickness of the AlO film when the number of cycles was 5 was 2.2 mm, and the cumulative thickness of the AlO film when the number of cycles was 40 cycles was 5.5 mm. Therefore, from this figure, when the wafer temperature is 140 ° C. and the processing chamber pressure is 100 Pa, the film thickness (deposition rate) of the AlO film formed per cycle is (5.5 mm−2.2 mm) / It can be seen that (40 cycles-5 cycles) = 0.09 Å / cycle. And it is possible to adjust the film thickness of the AlO film with good reproducibility by adjusting the number of executions of the cycle in which Al source introduction → Al source purge → oxidant introduction → oxidant purge is one cycle. I understand.

(Summary)
10 and 11, under the conditions that the wafer temperature in the HfO film formation step is 250 ° C., the wafer temperature in the AlO film formation step is 140 ° C., and the processing chamber pressure in each step is 100 Pa, (1) Hf raw material introduction (Introduction time 2 seconds) → Hf raw material purge → oxidizer introduction → oxidant purge is performed to form a HfO film having a thickness of 1.11 mm by executing one cycle, and (2) Al raw material introduction (introduction time 20 seconds) ) → Al raw material purge → oxidant introduction → oxidant purge is performed to form an AlO film having a thickness of 0.09 mm, and (1) and (2) are alternately performed a predetermined number of times. The HfAlO film can be formed by forming a HfAlO film (a film having a trace AlO composition) in which the composition ratio of HfO and AlO is 92.5: 7.5. It can be seen. In such a case, the composition ratio of AlO to the entire HfAlO film is 7.5%.

  10 and 11, under the conditions that the wafer temperature in the HfO film formation step is 250 ° C., the wafer temperature in the AlO film formation step is 140 ° C., and the processing chamber pressure in each step is 100 Pa, (1) Hf Raw material introduction (introduction time: 2 seconds) → Hf raw material purge → oxidant introduction → oxidant purge by performing 1 to 10 cycles to form a HfO film having a thickness of 1.11 to 11.1 mm, and (2) Al Raw material introduction (introduction time 20 seconds) → Al raw material purge → oxidant introduction → oxidation purge is performed by one cycle, and an AlO film having a film thickness of 0.09 mm is alternately formed a predetermined number of times to form an HfAlO film As a result, an HfAlO film (film with a trace AlO composition) in which the composition ratio of HfO and AlO is 99.2: 0.8 to 92.5: 7.5 is formed. You bet it can be seen that can be. In such a case, the composition ratio of AlO to the entire HfAlO film is 0.8 to 7.5%. Thus, the film thickness of the HfO film may be adjusted by the number of cycles of saturated ALD film formation.

  As described above, by forming the HfO film in the CVD mode or the ALD saturation mode and forming the AlO film in the ALD saturation mode, at least HfO: AlO = 99.2: 0.8 to 92.5: 7. 5 (the composition ratio of AlO with respect to the entire HfAlO film is 0.8 to 7.5%) is considered to be able to control the trace AlO composition.

<Preferred embodiment of the present invention>
Hereinafter, preferred embodiments of the present invention will be additionally described.

According to one aspect of the invention,
By carrying out this cycle at least once with the process of supplying and exhausting the first raw material containing the first metal element and the process of supplying and exhausting the oxidant as one cycle in the processing chamber containing the substrate, Forming a first metal oxide film containing the first metal element on the substrate;
By performing the cycle at least once with the step of supplying and exhausting the second raw material containing the second metal element and the step of supplying and exhausting the oxidizing agent into the processing chamber, Forming a second metal oxide film containing the second metal element on
Alternately performing a predetermined number of times to form a third metal oxide film containing the first metal element and the second metal element on the substrate,
When the metal oxide films are formed in the same film formation mode as the first material and the second material, the film thickness formed per cycle in the step of forming the second metal oxide film is Provided is a method for manufacturing a semiconductor device using a raw material that is smaller than the film thickness formed per cycle in the step of forming the first metal oxide film.

  Preferably, the film thickness formed per cycle in the step of forming the second metal oxide film is about 1/12 of the film thickness formed per cycle in the step of forming the first metal oxide film. About 1/5.

  Preferably, the first metal element is Hf (hafnium), Zr (zirconium), Ti (titanium), Al (aluminum), La (lanthanum), Si (silicon), Nb (niobium), Sr (strontium). , Ba (barium), Ta (tantalum), and Y (yttrium), and the second metal element is Hf (hafnium), Zr (zirconium), Ti (titanium), Al (aluminum), La (lanthanum) ), Si (silicon), Nb (niobium), Sr (strontium), Ba (barium), Ta (tantalum), or Y (yttrium).

  Preferably, the first metal element is hafnium, the first metal oxide film is a hafnium oxide film, the second metal element is aluminum, and the second metal oxide film is aluminum oxide. And the third metal oxide film is a hafnium aluminate film.

According to another aspect of the invention,
A processing chamber for accommodating the substrate;
A heater for heating the substrate in the processing chamber;
A first raw material supply system for supplying a first raw material containing a first metal element into the processing chamber;
A second raw material supply system for supplying a second raw material containing a second metal element into the processing chamber;
An oxidizing agent supply system for supplying an oxidizing agent into the processing chamber;
An exhaust system for exhausting the processing chamber;
By performing at least one cycle of the process of supplying and exhausting the first raw material and the process of supplying and exhausting the oxidant into the processing chamber containing the substrate, the cycle is performed on the substrate. Forming a first metal oxide film containing the first metal element, a process for supplying and exhausting the second raw material into the processing chamber, and a process for supplying and exhausting the oxidizing agent. By performing this cycle at least once as a cycle, the film forming process for forming the second metal oxide film containing the second metal element on the substrate is alternately performed a predetermined number of times. The first raw material supply system, the second raw material supply system, and the oxidant supply system so as to form a third metal oxide film containing the first metal element and the second metal element on the substrate. Controlling the heater and the exhaust system. A controller for, has,
The first raw material supply system and the second raw material supply system are configured to form the second metal oxide film when the metal oxide films are formed in the same film formation mode as the first raw material and the second raw material. A raw material is supplied such that the film thickness formed per cycle in the film forming process to be formed is smaller than the film thickness formed per cycle in the film forming process for forming the first metal oxide film. A configured substrate processing apparatus is provided.

200 wafer (substrate)
201 processing chamber 206 heater 280 controller

Claims (1)

By carrying out this cycle at least once with the process of supplying and exhausting the first raw material containing the first metal element and the process of supplying and exhausting the oxidant as one cycle in the processing chamber containing the substrate, Forming a first metal oxide film containing the first metal element on the substrate;
By performing the cycle at least once with the step of supplying and exhausting the second raw material containing the second metal element and the step of supplying and exhausting the oxidizing agent into the processing chamber, Forming a second metal oxide film containing the second metal element on
Alternately performing a predetermined number of times to form a third metal oxide film containing the first metal element and the second metal element on the substrate,
When the metal oxide films are formed in the same film formation mode as the first material and the second material, the film thickness formed per cycle in the step of forming the second metal oxide film is A method for manufacturing a semiconductor device, comprising using a raw material that is smaller than a film thickness formed per cycle in the step of forming a first metal oxide film.

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