Patent Publication Number: US-2015087140-A1

Title: Film forming method, film forming device, and film forming system

Description:
TECHNICAL FIELD 
     Exemplary embodiments of the present disclosure relate to a film forming method, and a film forming device, and a film forming system which may be used for performing the method, and more particularly, to film formation of a layer containing a dopant. 
     BACKGROUND 
     In manufacturing a semiconductor device, for example, a large scale integrated circuit (LSI), a process is performed to form a planar type, fin type, or wire type MOSFET (metal oxide semiconductor field effect transistor) on some regions of a processing target substrate (silicon substrate). In such a process, a film forming processing and various plasma treatments or doping processings are performed using an ion implantation device, a plasma film forming device, or a thermal CVD device in order to form p-type or n-type conductive regions such as, for example, a source region, a drain region and/or an extension region, in addition to a process of forming a fine circuit pattern by photolithography. 
     In the process of forming the MOSFET, a technology such as, for example, solid phase diffusion, ion beam implantation, or plasma doping, is usually used in the doping processings. The solid phase diffusion refers to a technology of forming a deposition film layer containing an element to be doped (dopant) on a processing target substrate through a CVD method, or diffusing a dopant by heating the processing target substrate within a gas atmosphere containing the dopant. The ion beam implantation refers to a technology of implanting a dopant to a processing target substrate using an ion beam having a relatively high energy. In addition, as described in Patent Document 1, the plasma doping refers to a technology of directly implanting a dopant to a processing target substrate by generating plasma of a gas containing the dopant and applying an RF bias to the processing target substrate. 
     Meanwhile, according to recent miniaturization of LSI semiconductors, three-dimensionally structured LSI semiconductor devices attract attention. For example, in the case of MOSFET, a fin type or nanowire type MOSFET is being developed. 
     PRIOR ART DOCUMENT 
     Patent Document 
     Patent Document 1: Japanese Patent Laid-Open Publication No. 2008-300687 
     SUMMARY OF THE INVENTION 
     Problem to be Solved 
     In the above-described solid phase diffusion method, heating is generally performed at a very high temperature. Thus, a diffusion layer in a semiconductor device/LSI substrate becomes very deeper than a desired depth (diffusion depth). As a result, it is difficult to cope with miniaturization of semiconductor elements which is recently strongly demanded. In addition, in the solid phase diffusion, an ion diffusion direction may not be controlled which may cause a dopant to be diffused in a longitudinal direction of a channel. Consequently, a source region and a drain region may be connected with each other. In addition, in the ion beam implantation and the plasma doping, irradiation amounts of ions on a three-dimensionally structured semiconductor substrate surface, i.e. a plurality of differently oriented uneven surfaces are different from each other. Therefore, it is difficult to perform uniform doping on the plurality of surfaces. 
     Accordingly, what is requested in the related art is to form a film including a dopant uniformly to follow a three-dimensionally structured semiconductor substrate surface. 
     Means to Solve the Problem 
     A film forming method according to an aspect of the present disclosure includes: (a) a step of supplying a first precursor gas of a semiconductor material into a processing vessel in which a processing target substrate is disposed, the first precursor gas being adsorbed onto the processing target substrate during the step; (b) a step of supplying a second precursor gas of a dopant material into the processing vessel, the second precursor gas being adsorbed onto the processing target substrate during the step; and (c) a step of generating plasma of a reaction gas within the processing vessel, a plasma treatment being performed during the step so as to modify a layer adsorbed onto the processing target substrate. In an exemplary embodiment, the plasma may be excited by microwaves. 
     The film forming method adsorbs the first precursor gas and the second precursor gas onto the processing target substrate by an atomic layer deposition (ALD) method and then, modifies an atom adsorption layer of a dopant adsorbed onto the processing target substrate by the plasma treatment. Thus, according to the present method, a film may be formed on a three-dimensionally structured surface, that is, a plurality of differently oriented surfaces uniformly and conformally. Meanwhile, the term, “conformally”, is used to express a situation in which doping is performed on a three-dimensionally structured surface uniformly without unevenness in concentration. 
     In an exemplary embodiment, the step of supplying the first precursor gas and the step of supplying second precursor gas may be separately performed. In this exemplary embodiment, the concentration of the dopant contained in the film formed on the processing target substrate may be adjusted based on a ratio of the number of times of performing the step of supplying the first precursor gas and the number of times of performing the step of supplying the second precursor gas. In an exemplary embodiment, the step of generating the plasma may include a step of performing a first plasma treatment and a step of performing a second plasma treatment. During the step of performing the first plasma treatment, the plasma treatment may be performed by the plasma of the reaction gas on a layer adsorbed onto the processing target substrate by the step of supplying the first precursor gas, and during the step of performing the second plasma treatment, the plasma treatment may be performed on a layer adsorbed onto the processing target substrate by the step of supplying the second precursor gas. 
     In an exemplary embodiment, each of the first precursor gas and the second precursor gas may further include hydrogen atoms and/or chlorine atoms, and during the step of performing the first plasma treatment and the step of performing the second plasma treatment, plasma of hydrogen gas which is a reaction gas may be excited. According to this exemplary embodiment, foreign matters other than the dopant may be removed from the layer adsorbed onto the processing target substrate by a reduction reaction using hydrogen. 
     In an exemplary embodiment, the step of supplying the first precursor gas and the step of supplying the second precursor gas may be performed simultaneously so that a mixture gas of the first precursor gas and the second precursor gas may be adsorbed onto the processing target substrate. In this exemplary embodiment, the concentration of the dopant contained in the film formed on the processing target substrate may be adjusted based on a ratio of the flow rate of the first precursor gas and the flow rate of the second precursor gas. In an exemplary embodiment, each of the first precursor gas and the second precursor gas may further include hydrogen atoms and/or chlorine atoms, and during the step of performing the first plasma treatment and the step of performing the second plasma treatment, plasma of hydrogen gas which is a reaction gas may be excited. According to this exemplary embodiment, foreign matters other than a desired dopant may be removed from the layer adsorbed onto the processing target substrate by a reduction reaction using hydrogen. 
     In addition, a film forming method according to an exemplary embodiment may further include a step of annealing the processing target substrate after a series of steps including the step in which the first precursor gas is adsorbed, the step in which the second precursor gas is adsorbed, and the step of generating the plasma are repeated one or more times. According to this exemplary embodiment, the film formed on the processing target substrate may be activated by annealing the processing target substrate. 
     In addition, a film forming method according to an exemplary embodiment may further include a step of forming a cap layer on a surface of the film formed on the processing target substrate prior to the step of annealing the processing target substrate. According to this exemplary embodiment, annealing may be performed while protecting the film formed through a series of the above-described steps, and as a result, the dopant contained in the film may be suppressed from being diffused outward from the film by the annealing. Therefore, reduction of the concentration of the dopant may be suppressed. 
     A film forming device according to another aspect of the present disclosure is provided with a processing vessel, a supply section, and a plasma generation section. A processing target substrate is disposed in the processing vessel. The supply section supplies a first precursor gas of a semiconductor material, and a second precursor gas of a dopant material into the processing vessel so that the first precursor gas and the second precursor gas are adsorbed onto the processing target substrate. The plasma generation section generates plasma of a reaction gas in the processing vessel so as to modify a layer adsorbed onto the processing target substrate by a plasma treatment. In an exemplary embodiment, the plasma generation section may use plasma excited by microwaves. 
     The film forming device may be intended to adsorb the first precursor gas and the second precursor gas onto the processing target substrate by an atomic layer deposition (ALD) method, and to modify a layer adsorbed onto the processing target substrate by the plasma treatment. According to the present film forming device, a film containing a dopant may be formed on a three-dimensionally structured semiconductor substrate surface uniformly and conformally. 
     A film forming device according to an exemplary embodiment may further include a control unit configured to control the supply section and the plasma generation section. 
     In an exemplary embodiment, the control unit may control: (a) the supply section to supply the first precursor gas into the processing vessel, (b) the plasma generation section to generate plasma of the reaction gas so as to perform a plasma treatment on a layer adsorbed onto the processing target substrate by supplying the first precursor gas, (c) the supply section to supply the second precursor gas into the processing vessel, and (d) the plasma generation section to generate plasma of the reaction gas so as to perform a plasma treatment on a layer adsorbed onto the processing target substrate by supplying the second gas. In this exemplary embodiment, the concentration of the dopant contained in the film formed on the processing target substrate may be adjusted based on a ratio of the number of times of supplying the first precursor gas and the number of times of supplying the second precursor gas. 
     In an exemplary embodiment, the supply section may supply a mixture gas of the first precursor gas and the second precursor gas into the processing vessel. The control unit may control the supply section to supply the mixture gas into the processing vessel, and control the plasma generation section to generate the plasma of the reaction gas so as to perform the plasma treatment on the layer adsorbed onto the processing target substrate by supplying the mixture gas. In this exemplary embodiment, the concentration of the dopant contained in the film formed on the processing target substrate may be adjusted based on a ratio of the flow rate of the first precursor gas and the flow rate of the second precursor gas. 
     In an exemplary embodiment, each of the first gas and the second gas may further include hydrogen atoms and/or chlorine atoms, and the plasma generation section may generate plasma of hydrogen gas which is the reaction gas. According to this exemplary embodiment, foreign matters other than the dopant may be removed from the layer adsorbed onto the processing target substrate by a reduction reaction using hydrogen. 
     A film forming system according to still another exemplary embodiment is a doping system using ALD film formation and is provided with a film forming device according to any one of the above-described aspects or exemplary embodiments and an annealing device configured to receive the processing target substrate processed by the film forming device, and anneal the processing target substrate. According to this film forming system, the film formed on the processing target substrate may be activated by annealing the processing target substrate. 
     A film forming system according to an exemplary embodiment may further include another ADD film forming device of a doping system. The another ALD film forming device may be connected with the film forming device through a vacuum conveyance system, and may receive the processing target substrate from the film forming device and form a cap layer on a surface of the processing target substrate. The annealing device may be connected to the separate film forming device and may anneal the processing target substrate conveyed from the separate film forming device. According to this exemplary embodiment, annealing may be performed while protecting the film formed on the processing target substrate, and as a result, the dopant contained in the film may be suppressed from escaping from the film. 
     Effect of the Invention 
     As described above, according to various aspects and exemplary embodiments of the present disclosure, a film containing a dopant may be formed to follow a three-dimensionally structured surface with a high uniformity. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a plan view schematically illustrating a film forming system according to a first exemplary embodiment. 
         FIG. 2  is a cross-sectional view illustrating a film forming device according to an exemplary embodiment. 
         FIG. 3  is a top side view schematically illustrating the film forming device of the exemplary embodiment. 
         FIG. 4  is a plan view illustrating the film forming device illustrated in  FIG. 3  in a state in which an upper part of a processing vessel is removed from the film forming device. 
         FIG. 5  is an enlarged cross-sectional view of a part of the film forming device illustrated in  FIG. 2 , in which a section taken by cutting a portion including the region R 1  in parallel to the axis X is illustrated. 
         FIG. 6  is a plan view illustrating an injection portion of the gas supply section  16 , an exhaust port of the exhaust section  18 , and an injection port of the gas supply section  20  of the film forming device illustrated in  FIG. 2  which are viewed from the lower side, i.e. from the mounting table side. 
         FIG. 7  is an exploded perspective view of a unit which defines the injection portion  16   a , the exhaust port  18   a , and the injection port  20   a.    
         FIG. 8  is a plan view of the unit illustrated in  FIG. 7  when viewed from the upper side. 
         FIG. 9  is an enlarged cross-sectional view of the film forming device illustrated in  FIG. 2 , in particular, a portion in which the plasma generation section is provided. 
         FIG. 10  is a plan view illustrating one antenna of a film forming device according to an exemplary embodiment, which is viewed from the upper side. 
         FIG. 11  is a cross-sectional view taken along line XI-XI in  FIG. 10 . 
         FIG. 12  is a perspective view illustrating an exemplary semiconductor device which may be manufactured using a film forming device of an exemplary embodiment. 
         FIG. 13  is a perspective view illustrating another exemplary semiconductor device which may be manufactured using a film forming device of an exemplary embodiment. 
         FIG. 14  is a flowchart illustrating a film forming method according to an exemplary embodiment. 
         FIG. 15  is a flowchart illustrating a film forming method according to another exemplary embodiment. 
         FIG. 16  is a cross-sectional view schematically illustrating a film forming device according to another exemplary embodiment. 
     
    
    
     DETAILED DESCRIPTION TO EXECUTE THE INVENTION 
     Hereinafter, various exemplary embodiments will be described in detail with reference to drawings. In each drawing, the same or corresponding portions will be denoted by the same symbols. 
     First, descriptions will be made on a film forming system of an exemplary embodiment provided with a film forming device of a doping system using ALD film formation according to an exemplary embodiment.  FIG. 1  is a plan view schematically illustrating a film forming system according to an exemplary embodiment. The film forming system  100  is provided with mounting tables  102   a  to  102   d , accommodation containers  104   a  to  104   d , a loader module LM, load lock chambers LL 1  and LL 2 , process modules PM 1 , PM 2  and PM 3 , and a transfer chamber  110 . 
     The mounting tables  102   a  to  102   d  are arranged along one edge of the loader module LM. Above the mounting tables  102   a  to  102   d , the accommodation containers  104   a  to  104   d  are placed, respectively. A processing target substrate W is accommodated in each of the accommodation containers  104   a  to  104   d.    
     A conveyance robot Rb 1  is installed in the loader module LM. The conveyance robot Rb 1  takes out a processing target substrate W accommodated in any one of the accommodation containers  104   a  to  104   d , and conveys the processing target substrate W to a load lock chamber LL 1  or LL 2 . 
     The load lock chambers LL 1  and LL 2  are installed along another edge of the loader module LM and form a preliminary decompression chamber. Each of the load lock chambers LL 1  and LL 2  is connected to the transfer chamber  110  through a gate valve. 
     The transfer chamber  110  is a chamber which may be decompressed, and another conveyance robot Rb 2  is installed in the chamber. To the transfer chamber  110 , the process modules PM 1  to PM 3  are connected through corresponding gate valves, respectively. The conveyance robot Rb 2  takes out processing target substrates W from a load lock chamber LL 1  or LL 2 , and sequentially conveys the processing target substrates W to the process module PM 1 , PM 2 , and PM 3 . Each of the process modules PM 1 , PM 2  and PM 3  of the film forming system  100  may be a film forming device of an exemplary embodiment, a separate film forming device, or an annealing device. 
     Hereinafter, descriptions will be made on a film forming device  10  of a doping system using ALD film formation according to an exemplary embodiment, in which the film forming device  10  may be used as a process module PM 1 . First, reference will be made to  FIGS. 2 to 4 .  FIG. 2  is a cross-sectional view of a film forming device according to an exemplary embodiment.  FIG. 3  is a top side view schematically illustrating the film forming device of the exemplary embodiment.  FIG. 2  illustrates a section cut along line II-II in  FIG. 3 .  FIG. 4  is a plan view illustrating the film forming device illustrated in  FIG. 3  in a state in which an upper part of a processing vessel is removed from the film forming device. The film forming device  10  illustrated in  FIGS. 2 to 4  is a so-called semi-batch type film forming device which performs film formation by the ALD method. The film forming device  10  is provided with a processing vessel  12 , a mounting table  14 , a gas supply section  16 , an exhaust section  18 , a gas supply section  20 , and a plasma generation section  22 . 
     The processing vessel  12  is a substantially cylindrical container extending in an axis X direction. The processing vessel  12  defines a processing chamber C therein. The inner surface of the processing vessel  12  may be made of a metal, for example, aluminum subjected to a plasma resistance treatment (e.g., alumite treatment or thermal spray treatment of Y 2 O 3 ). In an exemplary embodiment, as illustrated in  FIG. 2 , the processing vessel  12  includes a lower part  12   a  and an upper part  12   b . The lower part  12   a  has a top opened cylinder shape, and includes a side wall and a bottom wall which define the processing chamber C. The upper part  12   b  is a closure that defines the processing chamber C from the upper side. The upper part  12   b  is attached to the top portion of the lower part  12   a  to close the top opening of the lower part  12   a . An elastic sealing member may be installed between the lower part  12   a  and the upper part  12   b  to seal the processing chamber C. 
     The mounting table  14  is installed within the processing chamber C defined by the processing vessel  12 . The mounting table  14  has substantially a disc shape. The mounting table  14  is configured to be rotatable about the axis X. In an exemplary embodiment, the mounting table  14  is rotationally driven about the axis X by a driving mechanism  24 . The driving mechanism  24  includes a driving device  24   a  such as a motor and a rotation shaft  24   b , and is attached to the lower part  12   a  of the processing vessel  12 . The rotation shaft  24   b  extends to the inside of the processing chamber C to be centered on the axis X as a central axis thereof, and is rotated about the axis X by a driving force from the driving device  24   a . A central portion of the mounting table  14  is supported on the rotation shaft  24   b . As a result, the mounting table  14  is rotated about the axis X. In addition, an elastic sealing member such as, for example, an O-ring may be installed between the lower part  12   a  of the processing vessel  12  and the driving mechanism  24 . 
     As illustrated in  FIGS. 2 and 4 , one or more mounting regions  14   a  may be provided on the top surface of the mounting table  14 . In an exemplary embodiment, a plurality of mounting regions  14   a  is arranged around the axis X. Each mounting region  14   a  is formed as a recess having a diameter which is approximately equal to or slightly larger than the diameter of a processing target substrate W mounted thereon. In the processing chamber C, a heater  26  is installed below the mounting table  14  so as to heat the processing target substrate W mounted on a mounting region  14   a . The processing target substrate W is conveyed to the processing chamber C through a gate valve G provided in the processing vessel  12 , and mounted on the mounting region  14   a  by a conveyance robot. In addition, after having been subjected to a processing by the film forming device  10 , the processing target substrate W is taken out from the processing chamber C through the gate valve G by the conveyance robot. The processing chamber C includes a first region R 1  and a second region R 2  arranged around the axis X. Accordingly, a processing target substrate W mounted on a mounting region  14   a  sequentially passes through the first region R 1  and the second region R 2 , following the rotation of the mounting table  14 . 
     Hereinafter, reference will be made to  FIGS. 5 and 6  in addition to  FIGS. 3 and 4 .  FIG. 5  is an enlarged cross-sectional view of a part of the film forming device illustrated in  FIG. 2  in which a section taken by cutting a portion including the region R 1  in parallel to the axis X is illustrated.  FIG. 6  is a plan view illustrating an injection portion of the gas supply section  16 , an exhaust port of the exhaust section  18 , and an injection port of the gas supply section  20  of the film forming device illustrated in  FIG. 2  which are viewed from the lower side, i.e. from the mounting table side. As illustrated in  FIGS. 3 to 6 , an injection portion  16   a  of the gas supply section  16  is provided above a first region R 1  to face the top surface of the mounting table  14 . In other words, in the region included in the processing chamber C, a region facing the injection portion  16   a  becomes the first region R 1 . 
     As illustrated in  FIGS. 5 and 6 , the injection portion  16   a  is formed with a plurality of injection ports  16   h . The gas supply section  16  supplies a precursor gas to the first region R 1  from the plurality of injection ports  16   h . When the precursor gas is supplied to the first region R 1 , the precursor gas is chemically adsorbed onto a surface of a processing target substrate W which passes through the first region R 1 . 
     In an exemplary embodiment, the precursor gas supplied from the injection portion  16   a  to the first region R 1  includes a first precursor gas and a second precursor gas. The first precursor gas is a precursor gas of a semiconductor material. In an exemplary embodiment, the first precursor gas may include silicon as the semiconductor material, and may further include chlorine atoms and/or hydrogen atoms. The first precursor gas is, for example, dichlorosilane (DCS). The second precursor gas is a precursor gas of a dopant material. The second precursor gas may include arsenic or phosphor as an n-type dopant material. In addition, the second precursor gas may include chlorine atoms and/or hydrogen atoms. The second precursor gas is, for example, AsClH 2  gas. Or, the second precursor gas may include boron as a p-type dopant material, and may further include chlorine atoms and/or hydrogen atoms. The second precursor gas is, for example, B(CH 3 ) 2 H gas. In addition, the first precursor gas and the second precursor gas may be supplied from the injection portion  16   a  in a switching manner, or a mixture gas of the first and second precursor gases may be supplied. 
     In an exemplary embodiment, as illustrated in  FIG. 6 , the edges defining the injection portion  16   a  includes two edges  16   e  defining the injection portion  16   a  from the circumferential direction. The two edges  16   e  extend to approach each other as approaching the axis X. The two edges  16   e  may extend, for example, in a radial direction with respect to the axis X. That is, the injection portion  16   a  may have substantially a fan shape in a plan view. The plurality of injection ports  16   h  is provided between the two edges  16   e . Here, a speed of each position within the processing target substrate W following the rotation of the mounting table  14  is varied depending on a distance from the axis X. That is, the speed at a position is increased in proportion to the distance from the axis X to the position. In the present exemplary embodiment, the injection portion  16   a  is configured such that the processing target substrate W faces more injection ports  16   h  at a position spaced farther away from the axis X. Accordingly, variations in exposure time for respective positions on the processing target substrate W with respect to the precursor gases may be reduced. 
     As illustrated in  FIGS. 5 and 6 , an exhaust port  18   a  is provided around the injection portion  16   a , and the exhaust section  18  evacuates the first region R 1  from the exhaust port  18   a . The exhaust port  18   a  of the exhaust section  18  faces the top surface of the mounting table  14  and, as illustrated in  FIG. 6 , extends along a closed path surrounding the outer circumference of the injection portion  16   a . Thus, in the film forming device  10 , a narrow exhaust port  18   a  surrounds the injection portion  16   a.    
     In addition, as illustrated in  FIGS. 5 and 6 , an injection port  20   a  of the gas supply section  20  is provided around the exhaust port  18   a , and the gas supply section  20  injects a purge gas from the injection port  20   a . The injection port  20   a  of the gas supply section  20  faces the top surface of the mounting table  14 , and extends along a closed path that surrounds the outer circumference of the exhaust port  18   a . As for the purge gas supplied by the gas supply section  20 , for example, an inert gas such as, for example, Ar gas or N 2  gas, may be used. When the purge gas is sprayed on the processing target substrate W, the precursor gas chemically adsorbed excessively on the processing target substrate W is removed in such a manner that an amount excessively adsorbed in addition to an adsorption amount of the first element is removed. 
     In the film forming device  10 , by exhaust from the exhaust port  18   a  and injection of the purge gas from the injection port  20   a , the precursor gas supplied to the first region R 1  is suppressed from leaking to the outside of first region R 1 , and, for example, a reaction gas supplied in the second region R 2  as described below or radicals thereof are also suppressed from infiltrating into the first region R 1 . That is, the exhaust section  18  and the gas supply section  20  separate the first region R 1  and the second region R 2  from each other. In addition, the injection port  20   a  and the exhaust port  18   a  has a stripe shape in a plan view which extends along the closed path surrounding the outer circumference of the injection portion  16   a . Thus, the width of each of the injection port  20   a  and the exhaust port  18   a  is narrowed. Accordingly, the separation between the first region R 1  and the second region R 2  may be realized while securing an angular range of the second region R 2  extending in the circumferential direction with respect to the axis X. In an exemplary embodiment, the width W2 of the exhaust port  18   a  and the width W3 of the injection port  20   a  extending between the first region R 1  and second region R 2  (see  FIG. 6 ) is smaller than the diameter W1 of the mounting regions  14   a  (see  FIG. 4 ). 
     In an exemplary embodiment, the film forming device  10  may be provided with a unit U which defines the injection portion  16   a , the exhaust port  18   a , and the injection port  20   a . Hereinafter, reference will be made to  FIGS. 7 and 8 .  FIG. 7  is an exploded perspective view of the unit which defines the injection portion  16   a , the exhaust port  18   a , and the injection port  20   a .  FIG. 8  is a plan view of the unit illustrated in  FIG. 7  when viewed from the upper side. The top surface of the unit U is illustrated in  FIG. 8 , and the bottom surface of the unit U is illustrated in  FIG. 6 . As illustrated in  FIGS. 5 to 8 , the unit U includes a first member M 1 , a second member M 2 , a third member M 3 , and a fourth member M 4  in which the first to fourth members M 1  to M 4  are stacked in this order from the top. The unit U is attached to the processing vessel  12  to be abutted on the bottom surface of the upper part  12   b  of the processing vessel  12 , and the elastic sealing member  30  is provided between the bottom surface of the upper part  12   b  of the processing vessel  12  and the first member M 1 . The elastic sealing member  30  extends along the outer edge of the top surface of the first member M 1 . 
     Each of the first to fourth members M 1  to M 4  has substantially a fan shape in a plan view. The first member M 1  defines a recess at the bottom side thereof, in which the second to fourth members M 2  to M 4  are received. In addition, the second member M 2  defines a recess at the bottom side thereof, in which the third and fourth members M 3  and M 4  are received. The third member M 3  and the fourth member M 4  have plane sizes which are substantially equal to each other. 
     In the unit U, a gas supply path  16   p  is formed through the first to third members M 1  to M 3 . The gas supply path  16   p  is connected, at the upper end thereof, with a gas supply path  12   p  provided in the upper part  12   b  of the processing vessel  12 . A gas source  16   g  of the first precursor gas is connected to the gas supply path  12   p  through a valve  16   v  and a flow rate controller  17   c  such as a mass flow controller. In addition, the lower end of the gas supply path  16   p  is connected to a space  16   d  formed between the third member M 3  and the fourth member M 4 . The injection ports  16   h  of the injection portion  16   a  installed in the fourth member M 4  are connected to the space  16   d.    
     Between the upper part  12   b  of the processing vessel  12  and the first member M 1 , an elastic sealing member  32   a  such as, for example, an O-ring is provided to surround a connection portion between the gas supply path  12   p  and the gas supply path  16   p . By the elastic sealing member  32   a , the precursor gas supplied to the gas supply path  16   p  and the gas supply path  12   p  may be prevented from leaking out from the boundary between the upper part  12   b  of the processing vessel  12  and the first member M 1 . In addition, elastic sealing members  32   b  and  32   c  such as, for example, O-rings may be installed between the first member M 1  and the second member M 2 , and between the second member M 2  and the third member M 3 , respectively, to surround the gas supply path  16   p . By the elastic sealing members  32   b  and  32   c , the precursor gas supplied to the gas supply path  16   p  may be prevented from leaking out from the boundary between the first member M 1  and the second member M 2  and the boundary between the second member M 2  and the third member M 3 . Further, an elastic sealing member  32   d  is installed between the third member M 3  and the fourth member M 4  to surround the space  16   d . By the elastic sealing member  32   d , the precursor gas supplied to the space  16   d  may be prevented from leaking out from the boundary between the third member M 3  and the fourth member M 4 . 
     In addition, in the unit U, an exhaust path  18   q  is formed through the first and second members M 1  and M 2 . The exhaust path  18   q  is connected, at the upper end thereof, with an exhaust path  12   q  provided in the upper part  12   b  of the processing vessel  12 . The exhaust path  12   q  is connected to an exhaust device  34  such as, for example, a vacuum pump. In addition, the exhaust path  18   q  is connected, at the lower end thereof, to a space  18   d  provided between the bottom surface of the second member M 2  and the top surface of the third member M 3 . In addition, as described above, the second member M 2  defines a recess that accommodates the third member M 3  and the fourth member M 4 , and a gap  18   g  is provided between the inner surface of the second member M 2  that defines the recess and the lateral end surfaces of the third member M 3  and the fourth member M 4 . The space  18   d  is connected to the gap  18   g . The lower end of the gap  18   g  functions as the above-described exhaust port  18   a.    
     Between the upper part  12   b  of the processing vessel  12  and the first member M 1 , an elastic sealing member  36   a  such as, for example, an O-ring is installed to surround the connection portion between the exhaust path  18   q  and the exhaust path  12   q . By the elastic sealing member  36   a , the exhaust gas passing through the exhaust path  18   q  and the exhaust path  12   q  may be prevented from leaking out from the boundary between the upper part  12   b  of the processing vessel  12  and the first member M 1 . In addition, between the first member M 1  and the second member M 2 , an elastic sealing member  36   b  such as, for example, an O-ring is installed to surround the exhaust path  18   q . By the elastic sealing member  36   b , the gas passing through the exhaust path  18   q  may be prevented from leaking out from the boundary between the first member M 1  and the second member M 2 . 
     In the unit U, a gas supply path  20   r  is formed through the first member M 1 . The gas supply path  20   r  is connected, at the upper end thereof, with a gas supply path  12   r  provided in the upper part  12   b  of the processing vessel  12 . To the gas supply path  12   r , a gas source  20   g  of a purge gas is connected through a valve  20   v  and a flow rate controller  20   c  such as a mass flow controller. In addition, the lower end of the gas supply path  20   r  is connected to a space  20   d  provided between the bottom surface of the first member M 1  and the top surface of the second member M 2 . In addition, as described above, the first member M 1  defines the recess that accommodates the second to fourth members M 2  to M 4 , and a gap  20   p  is formed between the inner surface of the first member M 1  which defines the recess and the lateral surface of the second member M 2 . The gap  20   p  is connected to the space  20   d . In addition, the lower end of the gap  20   p  functions as the injection port  20   a  of the gas supply section  20 . Between the upper part  12   b  of the processing vessel  12  and the first member M 1 , an elastic sealing member  38  such as, for example, an O-ring is installed to surround a connection portion between the gas supply path  12   r  and the gas supply path  20   r . By the elastic sealing member  38 , the purge gas passing through the gas supply path  20   r  and the gas supply path  12   r  may be prevented from leaking out from the boundary between the upper part  12   b  and the first member M 1 . 
     Hereinafter,  FIGS. 2 to 4  will be referred to again, together with  FIG. 9 .  FIG. 9  is an enlarged cross-sectional view of the film forming device illustrated in  FIG. 2 , in particular, a portion in which the plasma generation section is provided. As illustrated in  FIGS. 2 to 4  and  FIG. 9 , the film forming device  10  is provided with a plasma generation section  22 . The plasma generation section  22  supplies a reaction gas to the second region R 2 , and supplies microwaves to the second region R 2 . Thus, plasma of the reaction gas is generated in the second region R 2  to perform a plasma treatment on a plasma gas layer adsorbed onto a processing target substrate W. In the second region R 2 , the precursor gas chemically adsorbed onto the processing target substrate W, i.e. the precursor gas layer may be modified by the plasma of the reaction gas. As for the reaction gas, for example, H 2  gas may be used. 
     The plasma generation section  22  may include one or more antennas  22   a  configured to supply microwaves to the second region R 2 . Each of the one or more antennas  22   a  may include a dielectric plate  40  and one or more waveguides  42 . In the exemplary embodiment illustrated in  FIGS. 2 to 4 , four antennas  22   a  are arranged around the axis X. Each antenna  22   a  includes a dielectric plate  40  provided above the second region R 2 , and a waveguide  42  provided on the dielectric plate  40 . 
     Here, reference is also made to  FIGS. 10 and 11 .  FIG. 10  is a plan view illustrating one antenna of a film forming device according to an exemplary embodiment, when viewed from the upper side.  FIG. 11  is a cross-sectional view taken along line XI-XI in  FIG. 10 . As illustrated in  FIGS. 9 to 11 , the dielectric plate  40  is a substantially plate-shaped member which is made of a dielectric material such as quartz. The dielectric plate  40  is installed to face the second region R 2  and supported by the upper part  12   b  of the processing vessel  12 . 
     Specifically, in the upper part  12   b  of the processing vessel  12 , an aperture AP is formed such that the dielectric plate  40  is exposed to the second region R 2 . A plane size of the upper portion of the aperture AP (a size in a plane intersecting the axis X) is larger than a plane size of the lower portion of the aperture AP (a size in the plane intersecting the axis X). Accordingly, a stepped surface  12   s  facing upward is formed in the upper part  12   b  defining the aperture AP. Meanwhile, the edge of the dielectric plate  40  functions as a supported portion  40   s  and abutted on the stepped surface  12   s . When the supported portion  40   s  is abutted on the stepped surface  12   s , the dielectric plate  40  is supported on the upper part  12   b . In addition, an elastic sealing member may be installed between the stepped surface  12   s  and the dielectric plate  40 . 
     The dielectric plate  40  supported by the upper part  12   b  as described above faces the mounting table  14  through the second region R 2 . In the bottom surface of the dielectric plate  40 , a portion exposed from the aperture AP of the upper part  12   b , that is, the portion facing the second region R 2 , functions as a dielectric window  40   w . The edges of the dielectric window  40   w  include two edges  40   e  which approach each other as approaching the axis X. Due to the shape of the dielectric window  40   w , that is, the shape in which the circumferential length increases in proportion to the distance from the axis X, variations in exposure time for respective positions on the processing target substrate W in relation to the plasma of the reaction gas may be reduced. In addition, in a plan view, the dielectric plate  40  including the dielectric window  40   w  and the supported portion  40   s  may be formed substantially in a fan shape, or in a polygonal shape so as to facilitate the machining thereof. 
     A waveguide  42  is installed on the dielectric plate  40 . The waveguide  42  is a rectangular waveguide, and an internal space  42   i  in which the microwaves propagate is provided on the dielectric plate  40  to extend substantially in a radial direction with respect to the axis X in the upper side of dielectric window  40   w . In an exemplary embodiment, the waveguide  42  may include a slot plate  42   a , an upper member  42   b , and an end member  42   c.    
     The slot plate  42   a  is a plate-shaped member made of a metal, and defines the internal space  42   i  of the waveguide  42  from the bottom side thereof. The slot plate  42   a  is in contact with the top surface of the dielectric plate  40  to cover the top surface of the dielectric plate  40 . The slot plate  42   a  includes a plurality of slot holes  42   s  in the portion defining the internal space  42   i.    
     On the slot plate  42   a , the upper member  42   b  made of a metal is installed to cover the slot plate  42   a . The upper member  42   b  defines the internal space  42   i  of the waveguide  42  from the top side thereof. The upper member  42   b  may be fastened to the upper part  12   b  of the processing vessel  12  to sandwich the slot plate  42   a  and the dielectric plate  40  between the upper member  42   b  and the upper part  12   b  of the processing vessel  12 . 
     The end member  42   c  is made of a metal, and installed on a longitudinal end portion of the waveguide  42 . That is, the end member  42   c  is attached to one ends of the slot plate  42   a  and the upper member  42   b  to close one end of the internal space  42   i . A microwave generator  48  is connected to the other end of the waveguide  42 . The microwave generator  48  may generate microwaves of, for example, about 2.45 GHz, and supply the microwaves to the waveguide  42 . The microwaves generated by the microwave generator  48  and propagated to the waveguide  42  are supplied to the dielectric plate  40  through the slot holes  42   s  of the slot plate  42   a , and supplied to the second region R 2  through the dielectric window  40   w . In an exemplary embodiment, the microwave generator  48  may be commonly shared by a plurality of waveguides  42 . In another exemplary embodiment, a plurality of microwave generators  48  may be connected to a plurality of waveguides  42 , respectively. When the intensity of the microwaves generated by the microwave generators  48  is adjusted using one or more microwave generator  48  connected to a plurality of antennas  22   a  as described above, the intensity of the microwaves imparted to the second region R 2  may be enhanced. 
     In addition, the plasma generation section  22  includes a gas supply section  22   b . The gas supply section  22   b  supplies a reaction gas to the second region R 2 . As described above, the reaction gas serves to modify a precursor gas layer chemically adsorbed onto a processing target substrate W, and may be, for example, H 2  gas. In an exemplary embodiment, the gas supply section  22   b  may include a gas supply path  50   a  and an injection port  50   b . The gas supply path  50   a  is formed in the upper part  12   b  of the processing vessel  12  to extend, for example, around the aperture AP. In addition, in the upper part  12   b  of the processing vessel  12 , the injection port  50   b  is formed to inject the reaction gas supplied to the gas supply path  50   a  toward the lower side of the dielectric window  40   w . In an exemplary embodiment, a plurality of injection ports  50   b  may be provided around the aperture AP. In addition, a gas source  50   g  of the reaction gas may is connected to the gas supply path  50   a  through a valve  50   v  and a flow rate controller  50   c  such as a mass flow controller. 
     According to the plasma generation section  22  configured as described above, the reaction gas is supplied to the second region R 2  by the gas supply section  22   b , and in addition, microwaves are supplied to the second region R 2  by the antenna  22   a . As a result, plasma of the reaction gas is generated in the second region R 2 . In other words, the second region R 2  is a region where the plasma of the reaction gas is generated. As illustrated in  FIG. 4 , the angular range of the second region R 2  extending in the circumferential direction with respect to the axis X is wider than the angular range of the first region R 1  extending in the circumferential direction. The precursor gas layer chemically adsorbed onto the processing target substrate W is modified by the plasma of the reaction gas generated in the second region R 2 . In addition, as illustrated in  FIG. 4 , in the lower part  12   a  of the processing vessel  12 , an exhaust port  22   h  is formed below the outer edge of the mounting table  14 . To the exhaust port  22   h , an exhaust device  52  illustrated in  FIG. 9  is connected. 
     Referring to  FIG. 2  again, the film forming device  10  may further include a control unit  60  configured to control respective elements of the film forming device  10 . The control unit  60  may be a computer which is provided with, for example, a central processing unit (CPU), a memory, and an input device. When the CPU is operated according to a program stored in the memory in the control unit  60 , each element of the film forming device  10  may be controlled. In an exemplary embodiment, the control unit  60  may transmit: a control signal to the driving device  24   a  so as to control the rotating speed of the mounting table  14 ; a control signal to the power source connected to the heater  26  so as to control the temperature of the processing target substrate W; a control signal to the valve  16   v  and the flow rate controller  16   c  so as to control the flow rate of the first precursor gas; a control signal to the valve  17   v  and the flow rate controller  17   c  so as to control the flow rate of the second precursor gas; a control signal to the exhaust device  34  connected to the exhaust port  18   a  so as to control the exhaust amount of the exhaust device  34 ; a control signal to the valve  20   b  and the flow rate controller  20   c  so as to control the flow rate of the purge gas; a control signal to the microwave generator  48  so as to control the microwave power; a control signal to the valve  50   v  and the flow rate controller  50   c  so as to control the flow rate of the reaction gas; and a control signal to the exhaust device  52  so as to control the exhaust amount of the exhaust device  52 . 
     The film forming device  10  may cause the first precursor gas to be chemically adsorbed onto the surface of the processing target substrate W in the first region R 1 , and modify the first precursor gas layer adsorbed onto the processing target substrate W by the plasma of the reaction gas in the second region R 2 . For example, in a case where the first precursor gas is DCS, the film forming device  10  may extract chlorine from the DCS layer chemically adsorbed onto the surface of the processing target substrate W by a reduction reaction by the plasma of hydrogen gas, and form a silicon atom film on the surface of the processing target substrate W. In addition, the film forming device  10  may cause the second precursor gas to be chemically adsorbed onto the surface of the processing target substrate W in the first region R 1 , and modify the second precursor gas layer adhered to the processing target substrate W by the plasma of the reaction gas in the second region R 2 . For example, in a case where the second precursor gas is AsClH 2  gas, the film forming device  10  may extract chlorine from the AsClH 2  gas layer chemically adsorbed onto the surface of the processing target substrate W by the reduction reaction by the plasma of the hydrogen gas, and form an As atom layer on the surface of the processing target substrate W. In addition, the pressure of the second region R 2  is preferably 1 Torr (133.3 Pa) or higher. For example, the pressure of the second region R 2  is preferably in a range of 1 Torr (133.3 Pa) to 50 Torr (6666 Pa), and more preferably, in a range of 1 Torr (133.3 Pa) to 10 Torr (1333 Pa. When the plasma of the hydrogen gas is excited under the pressure, a lot of hydrogen ions are produced, and the reduction action for extracting chlorine from the first precursor gas layer and the second precursor gas layer may be exhibited more suitably. 
     In addition, in the film forming device  10 , the gas to be supplied to the first region R 1  while the processing target substrate W passes through the first region R 1  by the rotation of the mounting table  14  may be selected from the first precursor gas and the second precursor gas. Accordingly, in the film forming device  10 , the concentration of a dopant in a film formed on the processing target substrate W may be adjusted by adjusting a ratio of the number of times of supplying the first precursor gas to the first region R 1  and the number of times of supplying the second precursor gas to the first region R 1 . 
     In addition, in another exemplary embodiment, the film forming device  10  may supply a mixture gas of the first precursor gas and the second precursor gas to the first region R 1 . In this exemplary embodiment, the concentration of the dopant in the film formed on the processing target substrate W may be adjusted by adjusting a ratio of the flow rate of the first precursor gas and the flow rate of the second precursor gas in the mixture gas. 
     Next, an example of a semiconductor/an LSI, for which film formation by the film forming device  10  may be properly used, will be described.  FIG. 12  is a perspective view illustrating an exemplary semiconductor device which may be manufactured using the film forming device of an exemplary embodiment. The semiconductor device D 10  illustrated in  FIG. 12  is a fin type MOS transistor. The semiconductor device D 10  includes a substrate D 12 , an insulation film D 14 , a fin D 16 , a gate insulation film D 18 , and a gate electrode D 20 . The insulation film D 14  is provided on the substrate D 12 . The fin D 16  has a substantially rectangular parallelepiped shape, and provided on the insulation film D 14 . The gate insulation film D 18  is provided to cover a side surface and a top surface of a portion of the fin D 16 . The gate electrode D 20  is provided on the gate insulation film D 18 . 
     In the semiconductor device D 10 , extension regions E 10  and E 12  containing a low-concentration dopant are formed on the fin D 16  at both sides of the insulation film D 18 . In addition, in the semiconductor device D 10 , a source region Sr 10  and a drain region Dr 10  containing a high-concentration dopant are additionally formed on the fin D 16  adjacent to the extension regions E 10  and E 12 . 
     The fin D 16  of the semiconductor device D 10  has a three-dimensional shape, i.e. a top surface and side surfaces, as illustrated in  FIG. 12 . Because the film forming device  10  may perform film formation based on the ALD method, the film formation may also be performed on the three-dimensional shape, that is, the top surface and side surfaces. Accordingly, according to the film forming device  10 , it is possible to form the extension regions, the source region, and the drain region on the side surfaces and top surface of the fin D 16  with a uniform film thickness. 
     In addition to the fin type MOS transistor, the film forming device  10  may also be properly used for manufacturing a semiconductor device D 30  illustrated in  FIG. 13 . The semiconductor device D 30  illustrated in  FIG. 13  is a nanowire type MOS transistor which includes a nanowire portion D 32  having a substantially columnar shape, instead of the fin D 16  of the above-described semiconductor device D 10 . In the semiconductor device D 30 , a gate insulation film D 18  is formed on the entire surface of a part of the nanowire portion D 32  in the longitudinal direction, and a gate electrode D 20  is formed to cover the gate insulation film D 18 . In the semiconductor device D 30 , extension regions E 10  and E 12  are also formed on the nanowire portion D 32  at both sides of the insulation film, and a source region and a drain region are formed next to the extension regions. According to the film forming device  10 , it is possible to form the extension regions, the source region Sr 10 , and the drain region Dr 10  over three-dimensional surfaces of the nanowire portion D 32  with a uniform film thickness. In addition, the film forming device  10  may also be used for forming an extension region, a source region, and a drain region of a planar-type MOS transistor. 
     Hereinafter, reference will be made to  FIG. 1  again. After the film formation is performed by the film forming device  10 , the process module PM 2  receives a processing target substrate W conveyed by the conveyance robot Rb 2 . The process module PM 2  forms a cap layer on a surface of the processing target substrate W. The cap layer may be, for example, a SiN film, and prevent a dopant from escaping from the film due to annealing to be described later. In an exemplary embodiment, the process module PM 2  may have the same configuration as the film forming device  10 . In such an exemplary embodiment, the process module PM 2  may supply a precursor gas of silicon, for example, BTBAS (bis-tertial-butyl amino silane), to the first region R 1 , and generate plasma of nitrogen gas (N 2  gas) or NH 3  gas in the second region R 2 . 
     The processing target substrate W provided with the cap layer by the process module PM 2  is conveyed to the process module PM 3  by the conveyance robot Rb 2 . The process module PM 3  is an annealing device of an exemplary embodiment. As for the annealing device, a lamp annealing device using ordinary lamp-heating or a microwave annealing device using microwaves may be used. The process module PM 3  performs an annealing processing on the processing target substrate W accommodated therein. As a result, the process module PM 3  activates the film formed on the processing target substrate W and including the dopant. In an exemplary embodiment, the process module PM 3  may heat the processing target substrate W for about one sec at a temperature of 1050° C. within a N 2  gas atmosphere. The heating time of the annealing processing, is considerably shorter than the time required for a heating processing used for conventional solid phase diffusion and is, for example, preferably 0.1 sec to 10 sec, and more preferably, 0.5 sec to 5 sec. Accordingly, excessive diffusion of the dopant may be suppressed. For example, the diffusion of the dopant in a longitudinal direction of a channel of a semiconductor/an LSI may be suppressed. 
     Hereinafter, an exemplary embodiment of a film forming method using the film forming system  100  will be described.  FIG. 14  is a flowchart illustrating a film forming method according to an exemplary embodiment. In the film forming method illustrated in  FIG. 14 , first, at step S 1 , a processing target substrate W is conveyed to the process module PM 1 , that is, the film forming device  10 . Then, in the film forming device  10 , film formation including steps S 2  to S 8  is performed. In addition, at steps S 2  to S 8 , the processing target substrate W is heated to 200° C. to 400° C. by the heater  26 . 
     (First Precursor Gas Adsorption Step: Step S 2 ) 
     In the film forming device  10 , first, the processing target substrate W is sent to the first region R 1  by the rotation of the mounting table  14 . While step S 2  is performed, the first precursor gas is supplied to the first region R 1 . Accordingly, at step S 2 , the first precursor gas is chemically adsorbed onto a surface of the processing target substrate W. In an exemplary embodiment, dichlorosilane (DCS) is supplied to the first region as the first precursor gas at a flow rate of 30 sccm. 
     (Purge Step: Step S 3 ) 
     Subsequently, following the rotation of the mounting table  14 , the processing target substrate W passes through an area under the injection port  20   a . At step S 3 , the first precursor gas excessively adsorbed onto the processing target substrate W is removed by the inert gas injected from the injection port  20   a . In an exemplary embodiment, the inert gas is Ar gas and its flow rate is 540 sccm. 
     (Plasma Treatment Step: Step S 4 ) 
     Subsequently, following the rotation of the mounting table  14 , the processing target substrate W reaches the second region R 2 . While step S 4  is performed, a reaction gas is supplied to the second region R 2  and microwaves as a plasma source are also supplied to the second region R 2 . In an exemplary embodiment, as for the reaction gas, hydrogen gas, i.e. H 2  gas is supplied to the second region R 2  at a flow rate of 60 sccm, and microwaves having a frequency of 2.45 GHz and a power of 3 kW are also supplied to the second region. As a result, plasma of the hydrogen gas is generated in the second region R 2 . In the second region R 2 , chlorine is extracted from the first precursor gas layer adsorbed onto the processing target substrate W by the reduction reaction by hydrogen ions in the plasma. As a result, a silicon atom layer is formed on the processing target substrate W. In addition, the pressure of the second region R 2  is preferably 1 Torr (133.3 Pa) or higher. For example, the pressure of the second region R 2  is preferably 1 Torr (133.3 Pa) to 50 Torr (6666 Pa), more preferably 1 Torr (133.3 Pa) to 10 Torr (1333 Pa). Under the high pressure, because a lot of hydrogen ions are generated, the reduction action for extracting the chlorine from the first precursor gas layer may be exhibited more properly. 
     (Second Precursor Gas Adsorption Step: Step S 5 ) 
     In the present method, after steps S 2  to S 4  are repeated one or more times, step S 5  is performed. At step S 5 , following the rotation of the mounting table  14 , the processing target substrate W reaches the first region R 1 , and at this time, the second precursor gas is supplied to the first region R 1 , and the second precursor gas is chemically adsorbed onto the surface of the processing target substrate W. In an exemplary embodiment, the second precursor gas is AsClH 2  gas, and is supplied to the first region R 1  at a flow rate of 30 sccm. 
     (Purge Step: Step S 6 ) 
     Subsequently, following the mounting table  14 , the processing target substrate W is passes through the area below the injection port  20   a . At step S 6 , the second precursor gas excessively adsorbed onto the processing target substrate W is removed by the inert gas injected from the injection port  20   a . In an exemplary embodiment, the inert gas is Ar gas, and its flow rate is 540 sccm. 
     (Plasma Treatment Step: Step S 7 ) 
     Subsequently, following the rotation of the mounting table  14 , the processing target substrate W reaches the second region R 2 . At step S 7 , a plasma treatment is performed on the processing target substrate W as at step S 4 . In an exemplary embodiment, hydrogen gas, i.e. H 2  gas is supplied to the second region R 2  as the reaction gas at a flow rate of 60 sccm, and microwaves having a frequency of 2.45 GHz and a power of 3 kW are also supplied to the second region. As a result, in the second region R 2  plasma of the hydrogen gas is generated. In the second region R 2 , chlorine is extracted from the second precursor gas layer adsorbed onto the processing target substrate W by the reduction reaction by hydrogen ions in the plasma. As a result, a dopant material layer is formed on the processing target substrate W. In the present exemplary embodiment, an As layer is formed. In addition, the pressure of the second region R 2  at step S 7  is preferably 1 Torr or higher like the pressure at step S 4 . 
     In the present method, after repeating steps S 5  to S 7  one or more times, at step S 8 , it is determined whether a series of steps (steps S 2  to S 7 ) are finished or not. In an exemplary embodiment, the number of times of repeating steps S 1  to S 7  is set in advance, and when the number of times of repeating steps S 1  to S 7  exceeds the predetermined number of times, the present method proceeds to step S 9 . 
     At step S 9 , the processing target substrate W is conveyed to the process module PM 2 . Then, at the next step S 10 , a cap layer is formed on the surface of the processing target substrate W in the process module PM 2 . In an exemplary embodiment, the cap layer may be formed by supplying BTBAS to the first region R 1  and generating plasma of NH 3  gas in the second region R 2  in the process module PM 2  which is a separate film forming device having the same configuration as the film forming device  10 . 
     At the next step S 11 , the processing target substrate W is conveyed from the process module PM 2  to the process module PM 3 . In the process module PM 3 , an annealing processing is performed on the processing target substrate W. As a result, the film formed on the processing target substrate W and containing a dopant is activated. In an exemplary embodiment, the processing target substrate W is heated for about 1 sec at a temperature of 1050° C. within a N 2  gas atmosphere. The heating is performed, for example, preferably for 0.1 sec to 10 sec, more preferably 0.5 sec to 5 sec. In the present method, the film containing the dopant may be activated by the annealing of such a short time, and excessive diffusion of the dopant may be suppressed. For example, it is possible to suppress the diffusion of the dopant in the longitudinal direction of a channel of a semiconductor device/LSI. In addition, as described above, since the film containing the dopant is formed on the surface of the processing target substrate W prior to the annealing processing, evaporation of the dopant may be suppressed. 
     Because the film forming method described in the foregoing is a film forming method based on an ALD method, a film containing a dopant may be formed to follow a three-dimensionally structured surface with a high uniformity. In addition, the concentration of the dopant in the film may be adjusted by adjusting a ratio of the number of times of performing step S 2  in which the first precursor gas is adsorbed onto a processing target substrate W and the number of times of performing step S 5  in which the second precursor gas is adsorbed onto the processing target substrate W. 
     Next, another exemplary embodiment of a film forming method using the film forming system  100  will be described with reference to  FIG. 15 .  FIG. 15  is a flowchart illustrating a film forming method according to another exemplary embodiment. The film forming method illustrated in  FIG. 15  is different from the film forming method illustrated in  FIG. 15  in that, at step S 22 , a mixture gas of the first precursor gas and the second precursor gas is supplied to the first region R 1  so that the mixture gas is adsorbed onto a processing target substrate W. In the film forming method illustrated in  FIG. 15 , the concentration of the dopant in the film formed on the processing target substrate W may be adjusted by adjusting a ratio of the flow rate of the first precursor gas and the flow rate of the second precursor gas in the mixture gas. 
     In the foregoing, various exemplary embodiments have been described. However, various modified embodiments may be made without being limited to the above-described exemplary embodiments. For example, the above-described film forming device  10  is a semi-batch type film forming device. However, as for a film forming device for forming a film containing a dopant, the film forming device illustrated in  FIG. 16  may also be used. 
     The film forming device  10 A illustrated in  FIG. 16  is a single wafer type film forming device which includes a processing head configured to supply a precursor gas. Specifically, the film forming device  10 A is provided with a processing vessel  12 A, a mounting table  14 A configured to hold a processing target substrate W within the processing vessel  12 A, and a plasma generation section  22 A configured to generate plasma of a reaction gas within the processing vessel  12 A. 
     The plasma generation section  22 A includes a microwave generator  202  configured to generate microwaves for plasma excitation, and a radial line slot antenna  204  configured to introduce the microwaves into the processing vessel  12 A. The microwave generator  202  is connected to a mode converter  208  configured to convert the mode of the microwaves through a waveguide  206 . The mode converter  208  is connected to a radial line slot antenna  204  through a coaxial waveguide  210  including an inner waveguide  210   a  and an outer waveguide  210   b . The microwaves generated by the microwave generator  202  are mode-converted in the mode converter  208  and then reach the radial line slot antenna  204 . The frequency of the microwaves generated by the microwave generator  202  is, for example, 2.45 GHz. 
     The radial line slot antenna  204  includes a dielectric window  212  configured to block an aperture  120   a  formed in the processing vessel  12 A, a slot plate  214  installed just above the dielectric window  34 , a cooling jacket  216  installed above the slot plate  214 , and a dielectric plate  218  disposed between the slot plate  214  and the cooling jacket  216 . The slot plate  214  has substantially a disc shape. In the slot plate  214 , a plurality of slot pairs, each of which includes two slots extending in orthogonal or crossing directions, is provided to be arranged in a radial direction and a circumferential direction of the slot plate  214 . 
     The dielectric window  212  is installed to face the processing target substrate W. The inner waveguide  210   a  is connected to the center of the slot plate  214 , and the outer waveguide  210   b  is connected to the cooling jacket  216 . The cooling jacket  216  also functions as a waveguide. Thus, the microwaves propagating between the inner waveguide  210   a  and the outer waveguide  210   b  penetrate the dielectric plate  218  and the dielectric window  212  while being reflected between the slot plate  214  and the cooling jacket  216 , thereby reaching the inside of the processing vessel  12 A. 
     A supply port  120   b  of a reaction gas is formed in a side wall of the processing vessel  12 A. A supply source  220  of the reaction gas is connected to the supply port  120   b . As for the reaction gas, hydrogen gas may be used as described above. In the film forming device  10 A, when the microwaves are irradiated to the reaction gas, plasma of the reaction gas is generated. 
     In the bottom portion of the processing vessel  12 A, an exhaust port  120   c  is formed so as to exhaust the gas within the processing vessel  12 A. A vacuum pump  224  is connected to the exhaust port  120   c  through a pressure regulator  222 . A temperature regulator  226  is connected to the mounting table  14 A so as to regulate the temperature of the mounting table  14 A. 
     The film forming device  10 A further includes a head portion  240  which is formed with injection ports  240   a  configured to inject the first precursor gas, the second precursor gas, and a purge gas. The head portion  240  is connected to a driving device  244  through a support  242 . The driving device  244  is disposed outside of the processing vessel  12 A. By the driving device  244 , the head portion  240  may be moved between a position where the head portion  240  faces the mounting table  14 A, and a retreat space  120   d  defined within the processing vessel  12 A. In addition, when the head portion  240  is positioned in the retreat space  120   d , a shutter  246  is moved to isolate the retreat space  120   d.    
     The support  242  defines a gas supply path configured to supply a gas to the injection ports  240   a , and a first precursor gas supply source  246 , a second precursor gas supply source  248 , and a purge gas supply source  250  are connected to the gas supply path of the support  242 . All the gas supply sources  246 ,  248  and  250  are flow rate-controllable gas supply sources. Accordingly, from the head portion  240 , the first precursor gas, the second precursor gas, and the purge gas may be selectively injected to the processing target substrate W. 
     In addition, the film forming device  10 A is provided with a control unit  256 . The control unit  256  is connected to the microwave generator  202 , the vacuum pump  224 , the temperature regulator  226 , the driving device  244 , and the supply sources  220 ,  246 ,  248 , and  250 . Thus, the control unit  256  may control each of the power of microwaves, the pressure within the processing vessel  12 A, the temperature of the mounting table  14 A, the movement of the head portion  240 , and the gas flow rate and supply timing of each of the reaction gas, the first precursor gas, the second precursor gas, and the purge gas. 
     A small space, to which the first precursor gas, the second precursor gas, and the purge gas are supplied, is defined between the head portion  240  of the film forming device  10 A and the mounting table  14 A. In addition, it is possible to always keep generated plasma of the reaction gas in the processing vessel  12 A. According to such a film forming device, the space configured to supply the precursor gas may be reduced in size, and because it is possible to always keep the generated plasma in the processing vessel  12 A, a high throughput may be realized. 
     In another exemplary embodiment, a single wafer type film forming device which does not include the head portion  240  may be used. In the single wafer type film forming device, the gases supplied to the processing vessel are switched in the order of the first precursor gas, the purge gas, the reaction gas, the second precursor gas, the purge gas, the reaction gas, and the purge gas so that a film containing a dopant as described above may be formed. 
     In addition, the above-described process module PM 3  performs annealing by heating a processing target substrate W. However, as for a process module for activating a film containing a dopant, a process module configured to irradiate microwaves to the processing target substrate W may be used. 
     In addition, as for the first precursor gas, a precursor gas of, for example, silane, disilane, methyl silane, dimethyl silane, chlorosilane (SiH 3 Cl), or trichlorosilane (SiHCl 3 ) may be used, instead of DCS. In addition, as for the second precursor gas, a mixture gas of B 2 H 6  and He, BF 3  gas, AsH 3  gas, AsH 4  gas, or PH 3  gas may be used. Further, when the precursor gas contains carbon, the reaction gas may include oxygen gas in addition to hydrogen gas. 
     In addition, although the above-described exemplary embodiments are mainly related to formation of a film containing silicon and a dopant, the film may contain other semiconductor materials or compound semiconductor materials such as III-V group compound semiconductors, instead of silicon. 
     A doping processing method of another exemplary embodiment is a method of doping a desired dopant to a processing target substrate. The method includes: (a) a step of supplying a first precursor gas of a semiconductor material into a chamber (processing vessel), in which a processing target substrate is disposed, so that the first precursor gas is adsorbed onto the processing target substrate, (b) a step of supplying a second precursor gas of the dopant material into the processing vessel so that the second precursor gas is adsorbed onto the processing target substrate, and (c) a step of performing a plasma treatment in an atmosphere gas so as to dope an atom adsorption layer adsorbed onto the processing target substrate within the processing vessel. In an exemplary embodiment, the plasma may be excited by microwaves. 
     This doping processing method causes the first precursor gas and the second precursor gas to be adsorbed onto the processing target substrate by the atomic layer deposition (ALD) method, and then dopes the dopant atom adsorption layer adsorbed onto the processing target substrate by the plasma treatment. Thus, according to the present method, it is possible to form a film containing a dopant on a three-dimensionally structured surface, that is, a plurality of differently oriented surfaces uniformly and conformally. The term “conformally” is used to express a situation in which doping is uniformly performed without unevenness in concentration on a three-dimensionally structured surface. 
     DESCRIPTION OF SYMBOLS 
       10 : film forming device,  12 : processing vessel,  14 : mounting table,  16 : gas supply section (first and second precursor gas supply section),  20 : gas supply section (purge gas supply section),  22 : plasma generation section,  60 : control unit,  100 : film forming system, PM 1 : process module (film forming device), PM 2 : process module (separate film forming device), PM 3 : process module (annealing device), W: processing target substrate