Abstract:
Disclosed are a substrate for electronic devices such as semiconductor devices and a method for processing the same, In the processing method, firstly a substrate for electronic devices is prepared and an insulating film (I) composed of a fluorocarbon (CF) is formed on the surface of the substrate. Then, fluorine (F) atoms exposed in the surface of the insulating film (I) are removed therefrom by bombarding the surface of the insulating film (I) with, for example, active species (KR + ) produced in a krypton (Kr) gas plasma. In this connection, the substrate is kept out of contact with moisture at least from immediately after the insulating film forming step until completion of the fluorine removing step.

Description:
FIELD OF THE INVENTION  
       [0001]     The present invention relates to a substrate for use in electronic devices such as a semiconductor device, a liquid crystal display, an organic EL device and the like, and a method for processing the substrate.  
       BACKGROUND OF THE INVENTION  
       [0002]     There has been proposed a multi-layered wiring structure as an approach for achieving a high integration of a semiconductor device. In order to obtain the multi-layered wiring structure, an n th  layer and an (n+1) th  layer are connected to each other through a conductive layer while thin films called interlayer insulating films are formed in areas other than the conductive layer. Although a SiO 2  oxide film has been widely used as a typical interlayer insulating film, there has been a demand to lower a relative dielectric constant of the interlayer insulating film to further accelerate the operation speed of the semiconductor device.  
         [0003]     In this regard, an insulating film (referred to as “CF insulating film,” hereinafter) made up of fluorine and carbon (fluorocarbon) has been gaining attention. By using this CF insulating film, the relative dielectric constant can be significantly reduced compared with a silicon oxide film.  
         [0004]     Forming of the CF insulating film is carried out, for example, in a plasma processing apparatus, by exciting, e.g., C 5 F 8  which is a source gas of fluorine and carbon and by depositing radicals generated thereby onto a substrate. At this time, a plasma gas used in generating plasma such as argon gas is converted into plasma by, e.g., microwave, and the source gas is excited by this plasma. (e.g., see Japanese Patent Laid-open Application No. H11-162960) However, as shown in  FIG. 10 , when forming the CF insulating film, fluorine atoms in the CF insulating film I are arranged at the surface side of the film and exposed at the surface of the film. The fluorine atoms have a high electronegativity and a characteristic of easily adsorbing water molecules. Consequently, if the fluorine atoms are left and exposed at the surface of the film, water molecules will be adsorbed to the fluorine atoms while the substrate is transferred, for example.  
         [0005]     Further, when the substrate is heated after the film is formed thereof, for example, the adsorbed water molecules are initiated to react with the fluorine atoms. The fluorine atoms that have been reacted with the water molecules gets released as a hydrogen fluoride gas from the CF insulating film I. Such hydrogen fluoride gas has a property of corroding and destroying the film. For example, the hydrogen fluoride gas may react with a barrier metal film formed between a conductive layer within a semiconductor device and the interlayer insulating film, to destroy and peel off the barrier metal film. This results in an improper multi-layered wiring structure of the semiconductor device, thereby significantly reducing the efficiency of manufacturing the semiconductor device.  
         [0006]     Further, the surface of the CF insulating film I may be degenerated by reacting with the water molecules, thereby deteriorating the leak characteristic of the CF insulating film. As a result, the insulating performance of the interlayer insulating film formed by the CF insulating film I decreases, thereby diminishing the performance of the semiconductor device.  
       SUMMARY OF THE INVENTION  
       [0007]     It is, therefore, an object of the present invention to provide a substrate for electronic device capable of suppressing fluorine atoms exposed at the surface of a CF insulating film from reacting with water molecules, and a method for processing the same.  
         [0008]     In order to achieve the above objects, a method of processing a substrate for electronic device in accordance with the present invention includes the steps of preparing a substrate for electronic device; forming an insulating film made up of fluorine and carbon onto a surface of the substrate; and releasing fluorine atoms exposed at the surface of the insulating film therefrom; wherein the substrate is kept out of contact with water molecules, at least, from immediately after the insulating film forming step until completion of the fluorine atom releasing step.  
         [0009]     With such a method, by releasing the fluorine atoms exposed at the surface of the insulating film from the insulating film before it could come in contact with water molecules, the reaction of the fluorine atoms with water molecules can be suppressed. Accordingly, since the hydrogen fluoride gas is not generated from the surface of the insulating film, other films are prevented from being damaged and peeled off by the hydrogen fluoride gas. Further, the surface of the insulating film is prevented from degeneration; thereby increasing a relative dielectric constant thereof is prevented as well.  
         [0010]     The releasing step of the fluorine atoms can be performed by making active species, generated in plasma of a rare gas or nitrogen gas, collide against the surface of the insulating film. In this way, the fluorine atoms at the surface of the insulating film are sputtered and released from the insulating film by the physical collisions of the active species.  
         [0011]     The fluorine atom releasing step may also be performed by exposing the substrate to plasma generated from a rare gas or nitrogen gas. In this way, with energy of the plasma itself, which is generated from a non-reactive gas such as a rare gas or nitrogen gas, and/or a photon energy getting released when the plasma is converted back to gas, the fluorine atoms at the surface of the insulating film can be released. The rare gas is selected from a group consisting of, for example, argon gas, xenon gas and krypton gas.  
         [0012]     It is preferred that the fluorine atom releasing step is performed within a plasma space having an electron temperature of less than 2 eV and an electron density of higher than 1×10 11  electrons/cm 3 . By exposing the substrate to such high density plasma space, the fluorine atoms can be efficiently released in a short period of time.  
         [0013]     The fluorine atom releasing step may be performed by irradiating electron beams or ultraviolet rays to the surface of the insulating film. In this way, the fluorine atoms at the surface of the insulating film can be released by the electron beams or the ultraviolet rays. Further, since the electron beams and the ultraviolet rays are penetrated even into the insulating film, fluorine atoms existing in an unstable state, due to an incomplete bonding with the insulating film, can also be released. As a result, the quality of the insulating film itself can also be improved.  
         [0014]     The substrate processing method may further include the step of forming a protective film on the insulating film to prevent water molecules from contacting with the surface of the insulating film. In this case, since water molecules are prevented from contacting with the insulating film because of the protective film, the reaction of the fluorine atoms with water molecules are more securely prevented.  
         [0015]     Another method of processing a substrate for electronic device in accordance with the present invention includes the steps of preparing a substrate for electronic device; forming an insulating film, made up of fluorine and carbon, onto a surface of the substrate; and forming a protective film on the insulating film for preventing water molecules from contacting with the surface of the insulating film.  
         [0016]     With such a method, water molecules are prevented from contacting with the surface of the insulating film because of the protective film, and it is prevented that the fluorine atoms exposed at the surface of the insulating film is reacted with water molecules. Consequently, other films are prevented from being damaged and peeled off which could result from generation of hydrogen fluoride gas. Further, it is also prevented that the surface of the insulating film is changed in quality to increase a relative dielectric constant of the insulating film.  
         [0017]     In this case, it is preferable that the substrate is kept out of contact with water molecules from immediately after the insulating film forming step until completion of the protective film forming step.  
         [0018]     Further, in order to achieve the above objects, a substrate for electronic device in accordance with the present invention is characterized in that an insulating film made up of fluorine and carbon is formed on the substrate and a protective film is formed on the insulating film to prevent water molecules from contacting with a surface of the insulating film.  
         [0019]     In accordance with the substrate for electronic device, the fluorine atoms at the surface of the insulating film are prevented from contacting water molecules and reacting therewith by the protective film. Consequently, no hydrogen fluorine gas is generated from the surface of the insulating film, so that the electronic device can be prevented from being damaged by the hydrogen fluoride gas. Further, it is prevented that the insulating film is degenerated to increase the relative dielectric constant thereof.  
         [0020]     The material for the protective film is selected from a group consisting of amorphous carbon, SiN, SiCN, SiC, SiCO and CN. By forming protective films with the material having a low relative dielectric constant, the relative dielectric constant of the whole films including the insulating film and the protective film can be maintained at low.  
         [0021]     It is preferred that the protective film has a thickness of less than 200 Å. In this way, the relative dielectric constant of the whole films including the protective film and the insulating film can be prevented from increasing. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0022]      FIG. 1  is a schematic view of a substrate processing system used in a processing method of a substrate for electronic device in accordance with the present invention.  
         [0023]      FIG. 2  is a cross sectional view of an insulating film forming apparatus in the system shown in  FIG. 1 .  
         [0024]      FIG. 3  is a top view of a source gas supply structure in the apparatus shown in  FIG. 2 .  
         [0025]      FIG. 4  is a cross sectional view of an insulating film processing apparatus in the system shown in  FIG. 1 .  
         [0026]      FIG. 5  is an exemplary diagram showing a state where fluorine atoms are released from the surface of a CF insulating film.  
         [0027]      FIG. 6  is a cross sectional view of an insulating film forming process apparatus having electronic beam irradiators.  
         [0028]      FIG. 7  is a schematic view of another substrate processing system used in the processing method of the substrate for electronic device in accordance with the present invention.  
         [0029]      FIG. 8  is a cross sectional view of an insulating film processing apparatus in the system shown in  FIG. 7 .  
         [0030]      FIG. 9  is an exemplary diagram showing a state where a protective film is formed on a CF insulating film.  
         [0031]      FIG. 10  is an exemplary diagram showing a state where fluorine atoms are exposed at the surface of the CF insulating film.  
         [0032]      FIG. 11A  is a graph showing a TDS measurement result for a substrate of a comparative example where no processing is conducted on the substrate after the CF insulating film is formed thereon.  
         [0033]      FIG. 11B  is a graph showing a TDS measurement result for a substrate of an example where the substrate is exposed to Ar plasma for 5 seconds after the CF insulating film is formed thereon.  
         [0034]      FIG. 11C  is a graph showing a TDS measurement result for a substrate of an example where the substrate is exposed to N 2  plasma for 5 seconds after the CF insulating film is formed. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0035]     Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.  
         [0036]     First, there will be described a substrate processing system used in a processing method of a substrate for electronic device in accordance with the present invention.  
         [0037]     As shown in  FIG. 1 , a substrate processing system  1  includes a cassette station  2  and a processing station  3  having a plurality of processing apparatuses  32  to  35 , the cassette station  2  and the processing station  3  being connected as a whole in the Y-direction (a horizontal direction in  FIG. 1 ). The cassette station  2  serves to transfer a plurality of substrates W (for example, in a state where they are accommodated in cassettes C) between the substrate processing system  1  and the outside thereof, and load and unload the substrates W to and from the respective cassettes C. Further, the processing station  3  is configured to process the substrates W one by one by using each of the processing apparatuses  32  to  35 .  
         [0038]     The cassette station  2  includes a cassette table  4  and a transfer chamber  5 . The cassette table  4  is configured to mount thereon two cassettes C arranged in the X-direction (a vertical direction in  FIG. 1 ). Provided within the transfer chamber  5  are a substrate transfer unit  6  constructed by a multi-joint robot and a pre-alignment stage  7 . The substrate transfer unit  6  is configured to transfer the substrates W between the cassettes C on the cassette table  4 , the pre-alignment stage  7 , and load-lock chambers  30 ,  31  of the processing station  3 , which will be described later.  
         [0039]     The processing station  3  includes a transfer path  8  formed at its middle portion and extending linearly in the Y-direction from the cassette station  2 . The transfer path  8  is covered with a casing  8   a  which is capable of enclosing the transfer path  8 . Since a gas supply line  21  communicating with a gas supply source  20  of a dry gas is connected with the casing  8   a , the dry gas can be supplied into the casing  8   a  from the gas supply source  20  through the gas supply line  21 . Further, a non-reactive gas such as a rare gas or nitrogen gas is employed as the dry gas. Connected with the casing  8   a  is a gas exhaust line  23  communicating with a negative pressure generator  22 , and the inside of the casing  8   a  can be depressurized by a gas exhaust through the gas exhaust line  23 . Accordingly, after replacing the atmosphere within the transfer path  8  with a specific dry air, the inner space of the transfer path  8  can be depressurized to a predetermined pressure. In other words, it is possible to maintain the inside of the transfer path  8  in an atmosphere free of moisture after eliminating moisture therefrom.  
         [0040]     Disposed at both sides of the transfer path  8  are the load-lock chambers  30 ,  31 , insulating film forming apparatuses  32 ,  33  and insulating film processing apparatuses  34 ,  35 . The load-lock chambers  30 ,  31  and the apparatuses  32  to  35  are connected to the transfer path  8  through respective gate valves  36 . The load-lock chambers  30 ,  31  are located adjacent to the transfer chamber  5  of the cassette station  2 , and the load-lock chambers  30 ,  31  are connected to the transfer chamber  5  through respective gate valves  37 . Accordingly, the substrates W within the transfer chamber  5  are transferred to the transfer path  8  via the load-lock chambers  30 ,  31 .  
         [0041]     Provided within the transfer path  8  are a transfer rail  38  and a substrate transfer device  39 , the transfer rail  38  extending in the Y-direction and the substrate transfer device  39  being capable of freely moving on the transfer rail  38 . The substrate transfer device  39  is constructed by a multi-joint robot and serves to transfer the substrates W between the load-lock chambers  30 ,  31 , the insulating film forming apparatuses  32 ,  33 , the insulating film processing apparatuses  34 ,  35  and the transfer path  8  through the corresponding gate valves  36 . With such constructions, the substrates W loaded into the transfer path  8  from the load-lock chambers  30 ,  31  can be selectively transferred to each of the apparatuses  32  to  35 , while maintaining the inside of the transfer path  8  in a dry atmosphere. In this way, a specific processing can be performed on the substrates W in each of the apparatuses  32  to  35 .  
         [0042]     Next, there will be described the configurations of the aforementioned insulating film forming apparatuses  32 ,  33  by taking the insulating film forming apparatus  32  as an example.  
         [0043]      FIG. 2  shows schematically a cross sectional view of the insulating film forming apparatus  32 . This insulating film forming apparatus  32  is a plasma CVD (chemical vapor deposition) apparatus for forming a CF insulating film made up of fluorine and carbon on the substrate W.  
         [0044]     As shown in  FIG. 2 , the insulating film forming apparatus  32  includes, for example, a processing chamber  50  of a cylindrical shape having a bottom wall with its top opened. The processing chamber  50  is formed of, e.g., aluminum alloy and grounded. A mounting table  51  for mounting the substrate W thereon is provided approximately at the middle portion of the bottom wall of the processing chamber  50 .  
         [0045]     An electrode plate  52  is embedded in the mounting table  51  and is connected to a bias high frequency power supply  53  of, e.g., 13.56 MHz which is provided at an outside of the processing chamber  50 . By applying a negative high voltage to the surface of the mounting table  51  from the high frequency power supply  53 , charged particles in plasma can be attracted thereto. Further, the electrode plate  52  is also connected to a DC power supply (not shown), which generates an electrostatic force on the surface of the mounting table  51  so that the substrate W can be electrostatically chucked onto the mounting table  51 .  
         [0046]     A heater  54  is provided within the mounting table  51 . The heater  54  is connected to a power supply  55  provided at an outside of the processing chamber  50  and generates heat with a power applied thereto from the power supply  55  to heat the mounting table  51  to a predetermined temperature. Provided within the mounting table  51  is, for example, a cooling jacket  56  through which a cooling medium flows. The cooling jacket  56  is in communication with a coolant supply unit  57  installed at an outside of the processing chamber  50 . The mounting table  51  can be cooled to a predetermined temperature by supplying the cooling medium of a predetermined temperature to the cooling jacket  56  from the coolant supply unit  57 .  
         [0047]     A dielectric window  61  made of quartz glass or the like is provided at the top opening of the processing chamber  50  through a sealing member  60  such as an  0 -ring for securing an airtight seal. By this dielectric window  61 , the processing chamber  50  is closed. Provided on the dielectric window  61  is a RLSA (Radial Line Slot Antenna) serving as a high frequency supply unit for supplying microwaves to generate plasma.  
         [0048]     The RLSA  62  includes an antenna main body  63  of a cylindrical shape with its bottom opened. Provided in the opening of the antenna main body  63  is a slot plate  64  of a disk shape having a plurality of slots. A phase delay plate  65  formed of a low loss dielectric material is provided on the slot plate  64  in the antenna main body  63 . A coaxial waveguide  67  communicating with a microwave oscillator  66  is connected with the top surface of the antenna main body  63 . The microwave oscillator  66  is installed at outside of the processing chamber  50  and can generate microwaves of a specific frequency, e.g., 2.45 GHz, to the RLSA  62 . The microwaves generated from the microwave oscillator  66  is compressed to have a shorter wavelength at the phase delay plate  65  after propagating through the RLSA  62 . Then, after generating circularly-polarized waves by the slot plate  64 , the microwaves are radiated into the processing chamber  50  through the dielectric window  61 .  
         [0049]     Provided at an upper portion of the processing chamber  50  are gas supply ports  70  for supplying a plasma generation gas. The gas supply ports  70  are formed at plural locations along the inner peripheral surface of the processing chamber  50 . Gas supply lines  72  communicating with a gas supply source  71  are connected at the respective gas supply ports  70 , the gas supply source  71  being installed at the outside of the processing chamber  50 . In this embodiment, an argon gas, a rare gas, is confined in the gas supply source  71 .  
         [0050]     A source gas supply structure  80  is provided between the mounting table  51  within the processing chamber  50  and the RLSA  62 . The supply structure  80  is formed in a disk shape, whose diameter is at least larger than that of the substrate W, and arranged so as to face both the mounting table  51  and the RLSA  62 . The inside of the processing chamber  50  is partitioned with the supply structure  80  into a plasma excitation region R 1  at the side of the RLSA  62  and a plasma diffusion region R 2  at the side of the mounting table  51 .  
         [0051]     As shown in  FIG. 3 , the source gas supply structure  80  has a series of source gas supply lines  81  disposed on the same plane approximately in a grid pattern. The gas supply lines  81  include annular-shaped lines  81   a  disposed at an outer peripheral portion of the supply structure  80  and grid-patterned lines  81   b  disposed orthogonally to each other at the inner side of the annular-shaped lines  81   a . As shown in  FIG. 2 , each of the gas supply lines  81  has a rectangular cross sectional shape.  
         [0052]     Further, as shown in  FIGS. 2 and 3 , the source gas supply structure  80  includes a plurality of openings  82  between the source gas supply lines  81 . As shown in  FIG. 2 , plasma generated in the plasma excitation region R 1  above the supply structure  80  is introduced into the plasma diffusion region R 2  below the supply structure  80  through the openings  82 .  
         [0053]     A planar dimension of each opening  82  is set to be shorter than the wavelength of the microwaves radiated from the RLSA  62 . By doing so, the microwaves radiated from the RLSA  62  are reflected at the source gas supply structure  80 , thereby suppressing the microwaves from entering the plasma diffusion region R 2 . By coating a passivation film on the surface of the supply structure  80 , i.e., the surface of the source gas supply lines, it is possible to prevent a sputtering of the supply structure  80  caused by charged particles in the plasma. In this way, the substrate W can be prevented from being contaminated by particles which otherwise would be sputtered.  
         [0054]     As shown in  FIG. 2 , source gas supply ports  83  are formed at the bottom surfaces of the supply lines  81  of the source gas supply structure  80 . These source gas supply ports  83  are disposed uniformly in the plane of the supply structure  80 . The source gas supply ports  83  may be disposed uniformly only in a region corresponding to the substrate W mounted on the mounting table  51 . A gas line  85  communicating with a source gas supply unit  84  disposed at the outside of the processing chamber  50  is connected to the source gas supply line  81 . The source gas supply unit  84  contains therein as a source gas, a gaseous mixture of fluorine and carbon, e.g., C 5 F 8  gas. The source gas supplied to the source gas supply lines  81  through the gas line  85  from the source gas supply unit  84  is injected into the below plasma diffusion region R 2  through the source gas supply ports  83 .  
         [0055]     Provided at the bottom portion of the processing chamber  50  are gas exhaust openings  90  for exhausting the atmosphere in the processing chamber  50 . Gas exhaust lines  92  communicating with a gas exhaust unit  91  such as a turbo molecular pump are connected to the respective gas exhaust openings  90 . The inside of the processing chamber  50  can be depressurized to a predetermined pressure by evacuating it through the exhaust openings  80 .  
         [0056]     The configurations of the insulating film forming apparatus  33  is same as those of the insulating film forming apparatus  32 , so descriptions thereon will be omitted.  
         [0057]     Next, there will be described the configurations of the aforementioned insulating film processing apparatuses  34 ,  35  by taking the insulating film processing apparatus  34  as an example.  
         [0058]      FIG. 4  shows schematically a cross sectional view of the insulating film processing apparatus  34 . The insulating film processing apparatus  34  is a plasma processing apparatus for processing an insulating film on a substrate W by generating plasma from a rare gas with a high frequency power and then by colliding active species in the plasma against the substrate W.  
         [0059]     As shown in  FIG. 4 , the insulating film processing apparatus  34  is formed of, e.g., an aluminum alloy and includes a processing chamber  100  of a cylindrical shape having a bottom wall with the top opened. A mounting table  101  is provided approximately at the middle wall of the bottom portion of the processing chamber  100 . An electrode plate  102  is embedded in the mounting table  101 , and is connected to a bias high frequency power supply  103  of, e.g., 13.56 MHz provided at an outside of the processing chamber  100 . A negative high voltage is applied to a surface of the mounting table  101  from the high frequency power supply  103 , so that positive ions, which are active species in plasma generated within the processing chamber  100 , are attracted toward the mounting table  101  to be made to collide at a high speed against the surface of the substrate W on the mounting table  101 . Further, the electrode plate  102  is also connected to a DC power source (not shown), which generates an electrostatic force on the surface of the mounting table  101 , so that the substrate W can be electrostatically chucked onto the mounting table  101 .  
         [0060]     A shower plate  111  is attached at the top opening of the processing chamber  100  through a sealing member  110  such as an  0 -ring for securing an airtight seal. The shower plate  111  is formed of, e.g., a dielectric material such as Al 2 O 3  or the like. The top opening of the processing chamber  100  is closed by the shower plate  111 . A RLSA  113  for supplying a microwave to generate plasma is provided at the upper side of the shower plate  111  with a cover plate  112  interposed therebetween.  
         [0061]     The shower plate  111  is formed, e.g., in a disk shape and disposed so as to face the mounting table  101 . At the shower plate  111 , a plurality of gas supply openings  114  are formed to extend vertically therethrough. A gas supply line  115  is horizontally extended through the shower plate  111  to the middle portion thereof from the side surface of the processing chamber  100 , and is opened at the top surface of the shower plate  111 . By a recess formed in the top surface of the shower plate  111 , a gas channel  116  is formed between the shower plate  111  and the cover plate  112 . The gas channel  116  is in communication with the gas supply line  115  and each of the gas supply openings  114 . Accordingly, the plasma gas supplied to the gas supply line  115  is delivered to the gas channel  116  through the gas supply line  115  and is supplied into the processing chamber  100  through each of the gas supply openings  114  from the gas channel  116 .  
         [0062]     The gas supply line  115  is in communication with a gas supply source  117  installed at an outside of the processing chamber  100 . Krypton gas, which is a rare gas, is contained in the gas supply source  117 . Accordingly, the krypton gas serving as a plasma excitation gas can be supplied into the processing chamber  100 .  
         [0063]     The cover plate  112  is attached to the top surface of the shower plate  111  through a sealing member  118  such as an  0 -ring. The cover plate  112  is formed of, e.g., a dielectric material such as Al 2 O 3  or the like.  
         [0064]     The RLSA  113  includes an antenna main body  120  of approximately cylindrical shape with its bottom opened. In the opened portion of the antenna main body  120 , a slot plate  121  is provided, and a phase delay plate  122  is provided on the slot plate  121 . A coaxial waveguide  124  communicating with a microwave oscillator  123  is connected at the antenna main body  120 . The microwave oscillator  123  is installed at the outside of the processing chamber  100  and generates microwaves of a specific frequency, e.g., 2.45 GHz, to the RLSA  113 . The microwaves generated from the microwave oscillator  123  are compressed to have a shorter wavelength at the phase delay plate  122  after propagating through the RLSA  113 . Then, after generating circularly-polarized waves by the slot plate  121 , the microwaves are radiated into the processing chamber  100  through the cover plate  112  and the shower plate  111 .  
         [0065]     Provided at the bottom portion of the processing chamber  100  are gas exhaust openings  130  for exhausting the atmosphere in the processing chamber  100 . Gas exhaust lines  132  communicating with a gas exhaust unit  131  such as a turbo molecular pump are connected to the respective gas exhaust openings  130 . The inside of the processing chamber  100  can be depressurized to a predetermined pressure by evacuating it through the gas exhaust openings  90 . From this depressurization, water molecules present in the processing chamber  100  can be removed, thereby keeping the inside of the processing chamber  100  in an atmosphere free of water moisture.  
         [0066]     As discussed above, the insulating film processing apparatus  34  is configured such that, unlike the insulating film forming apparatus  32  shown in  FIG. 2 , no source gas supply structure is disposed between the RLSA  113  and the mounting table  101 . Further, since the insulating film processing apparatus  35  has the same configurations as the insulating film processing apparatus  34 , descriptions therefor will be omitted.  
         [0067]     Next, there will be described a method for processing the substrate W using the substrate processing system  1  constructed as set forth above by taking as an example a case of processing a substrate for a semiconductor device of a multi-layered structure, which is an electric device.  
         [0068]     For example, a substrate W, having a conductive film formed thereon as a wiring layer in a different process apparatus, is accommodated in the cassette C, and the respective cassette C is mounted on the cassette table  4  of the substrate processing system  1 , as shown in  FIG. 1 . At this time, the atmosphere in the transfer path  8  of the substrate processing system  1  is replaced with a dry gas supplied from the gas supply line  21 , for example, and then depressurized to a predetermined pressure by a gas exhaust through the gas exhaust line  23 . By doing so, the inside of the transfer path  8  is maintained in a depressurized atmosphere with no moisture.  
         [0069]     Once the cassette C is mounted on the cassette table  4 , the substrate W is unloaded from the cassette C by the substrate transfer unit  6  and transferred to the pre-alignment stage  7 . The substrate W that has undergone position alignment at the stage  7  is transferred to, for example, the load-lock chamber  30  through the gate valve  37  by the substrate transfer unit  6 . The substrate W in the load-lock chamber  30  is transferred to the insulating film forming apparatus  32  through the transfer path  8  by the substrate transfer device  39 .  
         [0070]     The substrate W transferred to the insulating film forming apparatus  32  is, as shown in  FIG. 2 , electrostatically chucked on the mounting table  51  within the processing chamber  50 . At this time, the substrate W is maintained at a temperature of, e.g., 350° C. by heat from the heater  54 . Subsequently, the processing chamber  50  is exhausted by the gas exhaust unit  91  to be depressurized to a predetermined pressure, e.g., approximately 13.3 Pa (100 mTorr). With such depressurization, the inside of the processing chamber  50  is also maintained in a moisture-free atmosphere.  
         [0071]     Once the inside of the processing chamber  50  is depressurized, argon gas is supplied into the plasma excitation region R 1  through the gas supply port  70 . From the RLSA  62 , microwaves of, e.g., 2.45 GHz are radiated toward the plasma excitation region R 1  located just below the RLSA  62 . With such microwave radiation, the argon gas is converted into plasma in the plasma excitation region R 1 . At this time, the microwaves radiated from the RLSA  62  are reflected at the source gas supply structure  80  and remained in the plasma excitation region R 1 . As a result, a so-called high density plasma space is formed within the plasma excitation region R 1 .  
         [0072]     Meanwhile, a negative voltage is applied by the bias high frequency power supply  53  to the mounting table  51 . Therefore, the plasma generated within the plasma excitation region R 1  is diffused into the plasma diffusion region R 2  through the openings  82  of the source gas supply structure  80 . C 5 F 8  gas is supplied to the plasma diffusion region R 2  through the source gas supply ports  83  of the source gas supply structure  80 . The C 5 F 8  gas is activated by, e.g., the plasma diffused from the plasma excitation region R 1 , and with the active species of the C 5 F 8  gas, a CF insulating film made up of fluorine and carbon atoms is formed on the substrate W. At this time, the fluorine (F) atoms are exposed by being arranged at the surface of the CF insulating film I as shown in  FIG. 10 .  
         [0073]     Since the gas used in forming the CF insulating film does not include H atoms, it is prevented that the F atoms in the film are combined with H atoms to generate HF. Therefore, the CF insulating film has an exceptionally high quality.  
         [0074]     After the CF insulating film I of a predetermined thickness is formed on the substrate W, the microwave radiation and the supply of the source gas and the plasma gas are stopped and the substrate W on the mounting table  51  is unloaded from the processing chamber  50  by the substrate transfer device  39 . The substrate W unloaded from the insulating film forming apparatus  32  is transferred to the insulating film processing apparatus  34  through the transfer path  8 . In the meantime, since the inside of the transfer path  8  is maintained in a dry atmosphere, there is no case where moisture comes in contact with the surface of the CF insulating film I on the substrate W.  
         [0075]     The insulating film processing apparatus  34  is maintained in advance in a depressurized atmosphere of, e.g., 33.3 Pa (250 mTorr) by the gas exhaust through the gas exhaust openings  130 . Accordingly, even when the substrate W is loaded therein, the substrate W is kept under a dry atmosphere. The substrate W transferred to the insulating film processing apparatus  34  is electrostatically chucked on the mounting table  101  while temperature is adjusted to, e.g., 30° C. While the substrate W is held on the mounting table  101 , a negative high voltage is applied to the mounting table  101  by the bias high frequency power  103 . Meanwhile, krypton gas is supplied downwardly at, e.g., 50 cm 3 /min from the shower plate  111  and microwaves of 2.45 GHz are radiated at a power of, e.g., 500 W from the RLSA  113 . With such microwave radiation, the krypton gas is converted into plasma and krypton ions Kr + , which are active species in the plasma, are attracted by a negative potential of the mounting table  101 . From this, the krypton ions Kr +  are made to collide at a high speed with the surface of the substrate W on the mounting table  101 . As shown in  FIG. 5 , due to the collisions of the Kr + , the fluorine (F) atoms exposed at the surface of the insulating film I on the substrate are separated or released from the insulating film I.  
         [0076]     For example, after the microwaves are irradiated for 5 seconds and the sufficient fluorine atoms at the surface of the CF insulating film I on the substrate W are separated therefrom, the irradiation of the microwaves and the supply of the krypton gas are stopped. Then, the substrate W is unloaded from the insulating film processing apparatus  34  by the substrate transfer device  39 . The unloaded substrate W is transferred to the load-lock chamber  31  through the transfer path  8  and accommodated within the cassette C on the cassette table  4  by the substrate transfer unit  6 . Next, in a different processing apparatus, after the CF insulating film I on the substrate W is patterned by using a photolithographic method, conductive film and/or a protective film is formed in a predetermined pattern, thereby manufacturing a semiconductor device.  
         [0077]     In accordance with the aforementioned embodiments, after forming the CF insulating film I on the substrate W, the active species are made to collide to the surface of the CF insulating film I at a high speed while preventing the CF insulating film I from contacting with moisture, so that the fluorine atoms are separated or reflected from the surface of the CF insulating film I. As a result, the fluorine atoms exposed at the surface of the CF insulating film I are removed therefrom, so there is no case where the fluorine atoms react with water molecules. Accordingly, hydrogen fluoride gas is prevented from being released from the CF insulating film I, and, for example, films in other layers within the semiconductor device are prevented from bring damaged or peeled-off. Further, degrading of the surface of the CF insulating film I and increase in relative dielectric constant of the CF insulating film I are also avoided. Also, in the aforementioned embodiments, although the krypton gas is used as a gas for forming plasma in the insulating film processing apparatus  34 , another rare gas such as helium, xenon, or argon gas, or nitrogen gas may be used.  
         [0078]     In the above-described embodiments, by positively actively colliding the active species, generated in plasma of a rare gas or nitrogen gas, against the CF insulating film I, the fluorine atoms at the surface of the CF insulating film I are made to separate or release therefrom. Alternatively, the fluorine atoms may be released by exposing the substrate W having the CF insulating film I to the plasma formed from the rare gas or the nitrogen gas.  
         [0079]     In this case, for example, krypton gas, a rare gas, is supplied from the shower plate  111  in the insulating film processing apparatus  34  of  FIG. 4 . Further, with the microwaves supplied from the RLSA  113 , the krypton gas is converted into plasma and a high density plasma space having, for example, an electron temperature of less than 2 eV and an electron density of higher than 1×10 11  electrons/cm 3  is formed within the processing chamber  100 . By exposing the substrate W to the high density plasma space, the fluorine atoms exposed at the surface of the CF insulating film I on the substrate W are separated or released therefrom due to, for example, energy created by the krypton ions and/or a photon energy which gets released when the krypton ions are converted back to the krypton gas. In this case, since the krypton gas having high excitation energy is employed, the release of the fluorine atoms can be efficiently carried out in a short period of time. Further, in this embodiment, a rare gas other than the krypton gas such as xenon gas, or argon gas or nitrogen gas may be used as a gas for generating plasma.  
         [0080]     Instead of the release method of the fluorine atoms mentioned in the above embodiment, the fluorine atoms may be released by irradiating electron beams to the substrate W having the CF insulating film I formed thereon.  
         [0081]     In this case, an insulating film processing apparatus  150  shown in  FIG. 6  is employed instead of the insulating film processing apparatus  34  of  FIG. 4 , for example. This insulating film processing apparatus  150  includes a closable processing chamber  151 . A mounting table  152  is disposed at a bottom middle portion of the processing chamber  151 . At the upper portion of the processing chamber  151 , a plurality of electron beam radiators  153  are provided to face the mounting table  152 . These electron beam radiators  153  are arranged to uniformly irradiate electron beams to the surface of a substrate W mounted on the mounting table  152 . The electron beam radiators  153  are configured to irradiate the electron beams by applying a high voltage thereto with a high voltage power supply  154  installed at outside of the processing chamber  151 . Further, the amount of irradiation of the electron beams can be controlled by, for example, a controller  155  which controls the operation of the high voltage power supply  154 .  
         [0082]     Provided at the bottom portion of the processing chamber  151  are gas exhaust openings  156  for exhausting the atmosphere in the processing chamber  151 . Gas exhaust lines  158  communicating with a gas exhaust unit  157  such as a turbo molecular pump are connected at the respective gas exhaust openings  156 . By the gas exhaust through the exhaust openings  156 , the inside of the processing chamber  151  can be depressurized to a predetermined pressure, thereby maintaining the inside of the processing chamber  151  in a depressurized atmosphere with no moisture.  
         [0083]     Further, upon release of the fluorine atoms, the inside of the processing chamber  151  is maintained in a dry atmosphere in advance by the gas exhaust through the gas exhaust openings  156 , and then the substrate W is loaded into the processing chamber  151 . The loaded substrate W is mounted onto the mounting table  152 , and the electron beams are then irradiated to the CF insulating film I on the substrate W from the electron beam radiators  153 . Due to the energy of the electron beams, the fluorine atoms exposed at the surface of the CF insulating film I are separated from the carbon atoms and get released. In this case, by the irradiation of the electron beams of the high energy, the fluorine atoms can be efficiently released. Further, since the electron beams are penetrated even to the inside of the CF insulating film I, fluorine atoms existing in an unstable state due to an incomplete bonding thereof are released, thereby increasing the quality of the CF insulating film I itself.  
         [0084]     In this embodiment, although the electron beams are irradiated to the surface of the CF insulating film I, ultraviolet rays may be radiated instead. In this case, ultraviolet irradiators  160  are provided at the insulating film processing apparatus  150  instead of the electron beam irradiators  153 . In a case where the ultraviolet rays are irradiated to the CF insulating film I, the release of the fluorine atoms are efficiently performed by the ultraviolet rays of high energy. Also, the fluorine atoms existing in an unstable state within the CF insulating film I can be released as well.  
         [0085]     In the aforementioned embodiments, by releasing the fluorine atoms exposed at the surface of the CF insulating film I, reaction of the fluorine atoms with water molecules is prevented. Alternatively, by forming a protective film for preventing water molecules from contacting with the CF insulating film formed on the substrate W, the reaction of the fluorine atoms with water molecules can also be prevented.  
         [0086]     In this case, as shown in  FIG. 7 , there will be used a substrate processing system  1 ′ having insulating film processing apparatuses  170 ,  171  for forming the protective film instead of the insulating film processing apparatuses  34 ,  35  of the processing system  1 . As for the insulating film processing apparatuses  170 ,  171 , a plasma CVD apparatus which uses plasma to form films is employed.  
         [0087]     AS shown in  FIG. 8 , the insulating film processing apparatus  170  includes a first, a second, and a third gas supply source  202 ,  203 ,  204  and a source gas supply unit  215  in place of the gas supply sources  71  and the source gas supply unit  84  shown in  FIG. 2 , respectively. The other configurations of the insulating film processing apparatus  170  are substantially the same as those of the insulating film processing apparatus  32  shown in  FIG. 2 .  
         [0088]     In this embodiment, in order to form a protective film made up of SiN on the substrate W, for example, hydrogen gas, argon gas, and nitrogen gas are contained in the first gas supply source  202 , the second gas supply source  203 , and the third gas supply source  204 , respectively. Further, silane gas is provided as a source gas within the source gas supply unit  215 .  
         [0089]     Moreover, since the configurations of the insulating film processing apparatus  171  are identical to those of the insulating film processing apparatus  170 , descriptions therefor will be omitted.  
         [0090]     In the substrate processing system  1 ′ constructed as described above, the CF insulating film I is first formed on the surface of the substrate W by using the insulating film forming apparatus  32  or  33 , as in the aforementioned embodiment. Then, the substrate W is transferred into the insulating film processing apparatus  170  or  171 , e.g., the processing apparatus  170  through the transfer path  8  while preventing the substrate from contacting with moisture. The inside of the processing apparatus  170  is depressurized in advance by the gas exhaust through the gas exhaust openings  90  and maintained in a dry atmosphere. The substrate W transferred into the insulating film processing apparatus  170  is mounted on the mounting table  51 .  
         [0091]     The substrate W is maintained at a temperature of, e.g., about 350° C. by the heater  54  within the mounting table  51 . A gaseous mixture of argon, hydrogen and nitrogen gases is supplied into the plasma excitation region R 1  through the gas supply ports  70 . The RLSA  62  radiates microwaves of 2.45 GHz to the plasma excitation region R 1  located therebelow, so that the gaseous mixture in the plasma excitation region is converted into plasma.  
         [0092]     A negative voltage is applied to the mounting table  51  by the bias high frequency power supply  53 , and the plasma within the plasma excitation region R 1  is diffused into the plasma diffusion region R 2  through the source gas supply structure  80 . Silane gas is supplied in the plasma diffusion region R 2  through the source gas supply ports  83 , and the silane gas is activated by the plasma diffused from the plasma excitation region R 1 . With radicals of the silane gas and/or the nitrogen gas, SiN deposits and grows on the surface of the CF insulating film I of the substrate W. Accordingly, as shown in  FIG. 9 , a protective film D made up of a SiN film (silicon nitride film) having a thickness of less than 200 Å and preferably less than 100 Å, e.g., about 30 to 90 Å is formed on the CF insulating film I.  
         [0093]     According to this embodiment, the substrate W can be transferred to the insulating film processing apparatus  170  while keeping the substrate W out of contact with water molecules, and the protective film D made up of SiN can be formed on the CF insulating film I in the processing apparatus  170 . From this, the reaction of the fluorine atoms exposed at the surface of the CF insulating film I with water molecules can be prevented. As a result of this, since hydrogen fluoride gas is prevented from being released from the CF insulating film I, other films within the semiconductor device are prevented from being damaged and peeled off by the hydrogen fluoride gas. Further, the CF insulating film I itself is prevented from changing in quality, which can be caused by reacting with water molecules, and increase in a dielectric constant thereof is prevented. Also, since the protective film D made up of SiN is formed on the CF insulating film I to have a thickness of less than 200 Å, the insulation quality of the whole films including the CF insulating film I and the protective film D can be maintained.  
         [0094]     The materials for the protective film D is not limited to the SiN, and another material such as amorphous carbon, SiCN, SiC, SiCO or CN, which has a low dielectric constant, may be used. The amorphous carbon includes an amorphous carbon containing hydrogen atoms in the film. In case of using the material of amorphous carbon, SiCN, SiC, SiCO or CN, the protective film D can be made thicker because it has a lower dielectric constant than SiN. Forming of the protective film D can be therefore carried out in a simpler manner. For example, when the material of the protective film D is amorphous carbon, SiCN, SiC, SiCO or CN, it preferably has a thickness of 5 to 500 Å. Further, the insulating film processing apparatus for forming the protective film D may be another film forming apparatus such as the plasma CVD apparatus using an electron cyclotron resonance, a sputtering apparatus, an ICP plasma apparatus, or a CCP plasma apparatus.  
         [0095]     Also, the carbon atoms at the surface of the CF insulating film I on the substrate W may be nitrified after releasing the fluorine atoms from the CF insulating film I as in the aforementioned embodiments (FIGS.  1  to  6 ) . In this case, the surface of the CF insulating film serves as a protective film.  
         [0096]     Further, the protective film D of the substrate W may be formed on the CF insulating film I after releasing the fluorine atoms from the CF insulating film I as in the aforementioned embodiments (FIGS.  1  to  6 ). In this way, the reaction of the fluorine atoms at the surface of the CF insulating film I with water molecules can be prevented more certainly.  
         [0097]      FIGS. 11A  to  11 C show results of a test for confirming quality and condition of a CF insulating film processed in accordance with the previous embodiments (FIGS.  1  to  5 ).  FIG. 11A  illustrates a comparative example showing a TDS (thermal desorption spectroscopy) measurement result of a case where no processing is conducted after the CF insulating film is formed on a substrate;  FIG. 11B  illustrates an example showing a TDS measurement result of a case where a substrate is exposed to Ar plasma for 5 seconds after the CF insulating film is formed thereon; and  FIG. 11C  illustrates an example showing a TDS measurement result of a case where a substrate is exposed to N 2  plasma for 5 seconds after the CF insulating film is formed thereon.  
         [0098]     As can be seen from  FIGS. 11A  to  11 C, by exposing the CF insulating film to the plasma, degassing amount (especially, F) from the film is reduced. Although  FIGS. 11A  to  11 C show representative degas elements, reduction of other elements such as C, CF, CF 2 , and SiF 3  have been also observed actually due to the exposure to the plasma. This means that, when the substrate is subjected to an anneal processing after the CF insulating film is formed thereon, the degassing amount from the CF insulating film is small. Accordingly, occurrences of voids are prevented between the CF insulating film and a barrier layer, a wiring layer, a protective layer or the like, which is laminated thereon, and a good adhesivity is maintained therebetween.  
         [0099]     Further, although some embodiments of the present invention have been discussed above, the present invention is not limited threrto and may be variously modified. For example, although the substrate W having the CF insulating film I thereon is used in the semiconductor device in the aforementioned embodiments, it may be used in other electronics, for example, a liquid crystal display and an organic EL device.  
       INDUSTRIAL APPLICABILITY  
       [0100]     The present invention is useful in forming an insulating film of a good quality made up of fluorine and carbon at a surface of a substrate for electronic device in a field of manufacturing the electronic devices such as the semiconductor device, the liquid crystal display and the organic EL device.