Abstract:
A substrate processing method implemented in a substrate processing system that includes an etching apparatus that carries out plasma etching processing on a substrate and a vacuum-type substrate transferring apparatus to which the etching apparatus is connected is provided. A first step includes forming a protective film on a rear surface of the substrate before the plasma etching processing is carried out. The protective film prevents the rear surface of the substrate from being scratched by an electrostatic chuck that electrostatically attracts the substrate during the plasma etching processing. A second step includes electrostatically attracting the substrate to the electrostatic chuck such that the electrostatic chuck directly contacts the rear surface of the substrate and of carrying out the plasma etching processing on the substrate. A third step includes removing the protective film from the rear surface of the substrate after the plasma etching processing has been carried out.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present application is a division of application Ser. No. 11/674,799 filed on Feb. 14, 2007, which claims benefit of U.S. provisional application Ser. No. 60/783,842, filed on Mar. 21, 2006 and Japanese Patent Application No. 2006-062883 filed on Mar. 8, 2006. The entire contents of application Ser. No. 11/674,799 is incorporated hereinto by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to a substrate processing system, and in particular to a substrate processing system having an etching apparatus having therein an electrostatic chuck that electrostatically attracts a substrate. 
         [0004]    2. Description of the Related Art 
         [0005]    A substrate processing system for forming wiring grooves or via holes in a desired pattern using plasma on a front surface of a wafer as a substrate is comprised of a photoresist apparatus for forming a resist film in a desired pattern on the front surface of the wafer, an etching apparatus for subjecting the front surface of the wafer to etching processing such as RIE (reactive ion etching) processing, and a washing apparatus for removing the resist film. Here, the photoresist apparatus has a coater that coats a photosensitive resin onto the front surface of the wafer, a stepper that exposes the photosensitive resin, and a developer that removes uncured photosensitive resin from the front surface of the wafer. Moreover, the etching apparatus has a housing chamber that houses the wafer and in which plasma is produced, and an electrostatic chuck that is disposed in the housing chamber and electrostatically attracts the wafer thereto while the wafer is being subjected to the etching processing (see, for example, Japanese Laid-open Patent Publication (Kokai) No. 2005-347620). 
         [0006]    Using the stepper, the photosensitive resin on the front surface of the wafer is irradiated with UV light or the like in a desired pattern. In recent years, as the desired pattern has become finer, UV light of a shorter wavelength, for example a wavelength of 193 nm, has come to be used. If the wavelength is shorter, then the depth of focus is also reduced, and hence the tolerances on the flatness and the inclination of the wafer are reduced. Moreover, with such a stepper, a plurality of pin-like projections support a rear surface of the wafer, and hence the flatness and the inclination of the wafer are greatly affected by scratches, foreign matter etc. on the rear surface of the wafer. 
         [0007]    Furthermore, to realize a complex semiconductor device wiring structure or electrode structure on a wafer, the wafer must be subjected to etching processing in the substrate processing system repeatedly, and each time the etching processing is carried out, the wafer is electrostatically attracted to the electrostatic chuck. The surface of the electrostatic chuck is covered with yttria (Y 2 O 3 ), and hence the rear surface of the attracted wafer, which is made of silicon (Si), may be scratched. Moreover, foreign matter present on the surface of the electrostatic chuck may be transferred onto the rear surface of the wafer. 
         [0008]    However, although foreign matter attached to the rear surface of a wafer can be removed by wet washing using a washing liquid or the like, no method is known for effectively removing scratches from the rear surface of a wafer. There is thus a fear that it may become impossible to maintain the flatness of a wafer within the allowed tolerance due to such scratches on the rear surface of the wafer. It is thus necessary to prevent the rear surface of a wafer from being scratched when the wafer is attracted by the electrostatic chuck. 
       SUMMARY OF THE INVENTION 
       [0009]    It is an object of the present invention to provide a substrate processing system that enables scratching of the rear surface of a substrate to be prevented. 
         [0010]    To attain the above object, according to the present invention, there is provided a substrate processing system comprising: an etching apparatus that carries out plasma etching processing on a substrate, the etching apparatus having therein an electrostatic chuck that electrostatically attracts the substrate, the electrostatic chuck contacting a rear surface of the substrate; a vacuum-type substrate transferring apparatus to which the etching apparatus is connected; a protective film forming apparatus that forms a protective film on the rear surface of the substrate before the plasma etching processing is carried out; and a protective film removing apparatus that removes the protective film from the rear surface of the substrate after the plasma etching processing has been carried out. 
         [0011]    According to the above construction, a protective film is formed on the rear surface of the substrate before the plasma etching processing is carried out, and then the protective film is removed from the rear surface of the substrate after the plasma etching processing has been carried out. As a result, the electrostatic chuck contacts the protective film formed on the rear surface of the substrate. The rear surface of the substrate can thus be prevented from being scratched when the substrate is attracted to the electrostatic chuck. 
         [0012]    Preferably, the protective film forming apparatus forms the protective film through vapor deposition processing. 
         [0013]    According to the above construction, the protective film forming apparatus forms the protective film through vapor deposition processing. As a result, the protective film can be formed reliably. 
         [0014]    More preferably, the vapor deposition processing is CVD processing. 
         [0015]    According to the above construction, the protective film forming apparatus forms the protective film through CVD processing. The protective film forming apparatus is thus a vacuum-type processing apparatus. Here, the etching apparatus is also a vacuum-type processing apparatus, and hence the protective film forming apparatus and the etching apparatus can be connected together via the vacuum-type substrate transferring apparatus. As a result, the formation of the protective film and the plasma etching processing on the substrate can be carried out one after the other smoothly. 
         [0016]    Alternatively, the substrate processing system further comprises an atmospheric-type substrate transferring apparatus connected to the vacuum-type substrate transferring apparatus, wherein the protective film forming apparatus is connected to the atmospheric-type substrate transferring apparatus, and forms the protective film through coating processing. 
         [0017]    According to the above construction, the protective film forming apparatus forms the protective film through coating processing. As a result, the protective film can be formed easily. Moreover, foreign matter may be produced in the protective film forming apparatus during the coating processing, but because the protective film forming apparatus is connected to the atmospheric-type substrate transferring apparatus and hence is not connected to the vacuum-type substrate transferring apparatus directly, foreign matter produced in the protective film forming apparatus can be prevented from infiltrating into the etching apparatus via the vacuum-type substrate transferring apparatus. 
         [0018]    Preferably, the protective film removing apparatus removes the protective film through ashing processing. 
         [0019]    According to the above construction, the protective film removing apparatus removes the protective film through ashing processing. The protective film removing apparatus is thus a vacuum-type processing apparatus. Here, the etching apparatus is also a vacuum-type processing apparatus, and hence the etching apparatus and the protective film removing apparatus can be connected together via the vacuum-type substrate transferring apparatus. As a result, the plasma etching processing on the substrate and the removal of the protective film can be carried out one after the other smoothly. 
         [0020]    Alternatively, the substrate processing system further comprises an atmospheric-type substrate transferring apparatus connected to the vacuum-type substrate transferring apparatus, wherein the protective film removing apparatus is connected to the atmospheric-type substrate transferring apparatus, and removes the protective film through wet washing processing. 
         [0021]    According to the present invention, the protective film removing apparatus removes the protective film through wet washing processing. As a result, the protective film can be removed easily. Moreover, a washing liquid may be scattered from the protective film removing apparatus during the wet washing processing, but because the protective film removing apparatus is connected to the atmospheric-type substrate transferring apparatus and hence is not connected to the vacuum-type substrate transferring apparatus directly, washing liquid and the like can be prevented from infiltrating into the etching apparatus via the vacuum-type substrate transferring apparatus. 
         [0022]    The above and other objects, features, and advantages of the invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0023]      FIG. 1  is a plan view schematically showing the construction of a substrate processing system according to a first embodiment of the present invention; 
           [0024]      FIG. 2  is a sectional view schematically showing the construction of a processing module in which a CF-type protective film is formed on a rear surface of each wafer; 
           [0025]      FIG. 3  is a sectional view schematically showing the construction of a processing module in which each wafer is subjected to RIE processing; 
           [0026]      FIG. 4  is a plan view schematically showing the construction of a substrate processing system according to a second embodiment of the present invention; 
           [0027]      FIG. 5  is a sectional view schematically showing the construction of a coating unit that forms a protective film made of a photosensitive resin on the rear surface of each wafer; and 
           [0028]      FIG. 6  is a sectional view schematically showing the construction of a cleaning unit that removes the protective film made of the photosensitive resin from the rear surface of each wafer. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0029]    Embodiments of the present invention will be described below with reference to the drawings. 
         [0030]    First, a substrate processing system according to a first embodiment of the present invention will be described. 
         [0031]      FIG. 1  is a plan view schematically showing the construction of the substrate processing system according to the present embodiment. 
         [0032]    As shown in  FIG. 1 , the substrate processing system  10  is comprised of a transfer module  11  (vacuum-type substrate transferring apparatus) having a hexagonal plan view, four processing modules  12  to  15  that are arranged in a radial manner around the transfer module  11  and in which predetermined processing is carried out on semiconductor device wafers (hereinafter referred to merely as “wafers”) W (substrates), a loader module  16  as a rectangular common transfer chamber, and two load lock modules  17  and  18  that are each disposed between the transfer module  11  and the loader module  16  so as to link the transfer module  11  and the loader module  16  together. 
         [0033]    The internal pressure of the transfer module  11  and each of the processing modules  12  to  15  is held at vacuum. The transfer module  11  is connected to the processing modules  12  to  15  by vacuum gate valves  19  to  22  respectively. 
         [0034]    In the substrate processing system  10 , the internal pressure of the loader module  16  is held at atmospheric pressure, whereas the internal pressure of the transfer module  11  is held at vacuum. The load lock modules  17  and  18  are thus provided respectively with a vacuum gate valve  23  or  24  in a connecting part between that load lock module and the transfer module  11 , and an atmospheric door valve  25  or  26  in a connecting part between that load lock module and the loader module  16 , whereby the load lock modules  17  and  18  are each constructed as a preliminary vacuum transfer chamber whose internal pressure can be adjusted. Moreover, the load lock modules  17  and  18  have respectively therein a wafer mounting stage  27  or  28  for temporarily mounting a wafer W being transferred between the loader module  16  and the transfer module  11 . 
         [0035]    The transfer module  11  has disposed therein a frog leg-type transfer arm  29  that can bend/elongate and turn. The transfer arm  29  transfers the wafers W between the processing modules  12  to  15  and the load lock modules  17  and  18 . 
         [0036]    In addition to the lock modules  17  and  18 , the loader module  16  has connected thereto three FOUP mounting stages  31  on each of which is mounted a FOUP (Front Opening Unified Pod)  30 , which is a container housing twenty-five of the wafers W. 
         [0037]    The lock modules  17  and  18  are connected to a side wall of the loader module  16  in a longitudinal direction of the loader module  16 , disposed facing the three FOUP mounting stages  31  with the loader module  16  therebetween. 
         [0000]    A SCARA-type dual arm transfer arm mechanism  32  for transferring the wafers W is disposed inside the loader module  16 , and three loading ports  33  through which the wafers W are introduced into the loader module  16  are disposed in a side wall of the loader module  16  in correspondence with the FOUP mounting stages  31 . The transfer arm mechanism  32  removes a wafer W from a FOUP  30  mounted on a FOUP mounting stage  31  through the corresponding loading port  33 , and transfers the removed wafer W into and out of the lock modules  17  and  18 . 
         [0038]    In the substrate processing system  10 , of the processing modules  12  to  15 , the processing module  12  (protective film forming apparatus) forms a CF-type protective film, described below, on a rear surface of each wafer W, the processing module  13  (etching apparatus) subjects each wafer W to the RIE processing, and the processing module  14  (protective film removing apparatus) removes the protective film formed on the rear surface of each wafer W. In the substrate processing system  10 , each wafer W is transferred around in the order processing module  12 , processing module  13 , processing module  14 . 
         [0039]      FIG. 2  is a sectional view schematically showing the construction of the processing module in which the CF-type protective film is formed on the rear surface of each wafer. 
         [0040]    As shown in  FIG. 2 , the processing module  12  has a chamber  34  as a box-shaped housing chamber in which a wafer W is housed, a wafer attracting portion  36  that is disposed on a ceiling portion  35  of the chamber  34 , an electrode  38  that is disposed on a bottom portion  37  of the chamber  34  facing the wafer attracting portion  36  separated from the wafer attracting portion  36  by a predetermined gap, and an exhaust pipe  39  for exhausting gas out from the chamber  34 . 
         [0041]    The wafer attracting portion  36  is a cylindrical projecting object, and has a plurality of vacuum suction holes (not shown) provided in a bottom surface thereof. A wafer W transferred into the chamber  34  is attracted by vacuum suction by the vacuum suction holes in the wafer attracting portion  36 , and thus held on the bottom surface of the wafer attracting portion  36 . Moreover, the wafer attracting portion  36  has a cushioning film  40  made of a heat-resistant resin such as a polyimide on the bottom surface thereof. A front surface of the wafer W thus contacts the bottom surface of the wafer attracting portion  36  via the cushioning film  40 , and hence there is no destruction of the shape of wiring grooves or via holes formed on the front surface of the wafer W. Moreover, the wafer attracting portion  36  has a heater (not shown) built therein, so that a temperature of the wafer W is held at a predetermined temperature while a protective film is being formed on the rear surface of the wafer W. 
         [0042]    The electrode  38  is comprised of a table-shaped electrically conductive member, and has a plurality of gas jetting holes (not shown) in a surface thereof facing the wafer attracting portion  36  (the upper surface). Moreover, a radio frequency power source  41  is connected to the electrode  38  via a matcher  42 . The radio frequency power source  41  supplies predetermined radio frequency electrical power to the electrode  38 . The electrode  38  thus applies radio frequency electrical power into a processing space S between the wafer attracting portion  36  and the electrode  38 . The matcher  42  reduces reflection of the radio frequency electrical power from the electrode  38  so as to maximize the efficiency of the supply of the radio frequency electrical power into the electrode  38 . 
         [0043]    A transfer port  43  for the wafers W is provided in a side wall of the chamber  34  in a position at the height of a wafer W that is being attracted to the wafer attracting portion  36 . The gate valve  19 , which is for opening and closing the transfer port  43 , is provided in the transfer port  43 . 
         [0044]    In the processing module  12 , the protective film is formed on the rear surface of each wafer W by CVD (chemical vapor deposition) processing. Specifically, upon a depositable processing gas such as a CF-type gas is supplied into the processing space S from the gas jetting holes in the electrode  38 , and radio frequency electrical power being applied into the processing space S, radicals and ions are produced from the CF-type gas, and these radicals and so on become attached to and accumulate on the rear surface of the wafer W attracted to the wafer attracting portion  36 , thus forming a CF-type protective film. At this time, excess radicals and so on are exhausted to the outside by the exhaust pipe  39 . 
         [0045]    The protective film formed in the processing module  12  preferably has a thickness of not more than 10 μm, preferably approximately 1 μm. Note that the type of the protective film formed is not limited to being a CF-type protective film, but rather may alternatively be a protective film made of amorphous carbon. 
         [0046]      FIG. 3  is a sectional view schematically showing the construction of the processing module in which each wafer is subjected to the RIE processing. 
         [0047]    As shown in  FIG. 3 , the processing module  13  has a chamber  44  in which a wafer W is housed. A cylindrical susceptor  45  is disposed in the chamber  44  as a stage on which the wafer is mounted. 
         [0048]    In the processing module  13 , a side exhaust path  46  that acts as a flow path through which gas above the susceptor  45  is exhausted out of the chamber  44  is formed between an inner wall of the chamber  44  and a side face of the susceptor  45 . A baffle plate  47  is disposed part way along the side exhaust path  46 . 
         [0049]    The baffle plate  47  is a plate-shaped member having a large number of holes therein, and acts as a partitioning plate that partitions the chamber  44  into an upper portion and a lower portion. The upper portion  48  of the chamber  44  partitioned by the baffle plate  47  has disposed therein the susceptor  45  on which the wafer W is mounted, and has plasma produced therein. Hereinafter, the upper portion of the chamber  44  is referred to as the “reaction chamber”. Moreover, the lower portion (hereinafter referred to as the “manifold”)  51  of the chamber  44  has provided therein a roughing exhaust pipe  49  and a main exhaust pipe  50  that exhaust gas out from the chamber  44 . The roughing exhaust pipe  49  has a DP (dry pump) (not shown) connected thereto, and the main exhaust pipe  50  has a TMP (Turbo-Molecular Pump) (not shown) connected thereto. Moreover, the baffle plate  47  captures or reflects ions and radicals produced in a processing space S′, described below, in the reaction chamber  48 , thus preventing leakage of the ions and radicals into the manifold  51 . 
         [0050]    The roughing exhaust pipe  49 , the main exhaust pipe  50 , the DP, the TMP, and so on together constitute an exhausting apparatus. The roughing exhaust pipe  49  and the main exhaust pipe  50  exhaust gas in the reaction chamber  48  out of the chamber  44  via the manifold  51 . Specifically, the roughing exhaust pipe  49  reduces the pressure in the chamber  44  from atmospheric pressure down to a low vacuum state, and the main exhaust pipe  50  is operated in collaboration with the roughing exhaust pipe  49  to reduce the pressure in the chamber  44  from atmospheric pressure down to a high vacuum state (e.g. a pressure of not more than 133 Pa (1 Torr)), which is at a lower pressure than the low vacuum state. 
         [0051]    A lower radio frequency power source  52  is connected to the susceptor  45  via a matcher  53 . The lower radio frequency power source  52  supplies predetermined radio frequency electrical power to the susceptor  45 . The susceptor  45  thus acts as a lower electrode. The matcher  53  reduces reflection of the radio frequency electrical power from the susceptor  45  so as to maximize the efficiency of the supply of the radio frequency electrical power into the susceptor  45 . 
         [0052]    Provided in an upper portion of the susceptor  45  is a disk-shaped electrostatic chuck  55  made of an insulating material, for example yttria, alumina (Al 2 O 3 ) or silica (SiO 2 ), having an electrode plate  54  therein. When a wafer W is mounted on the susceptor  45 , the wafer W is disposed on the electrostatic chuck  55 . A DC power source  56  is electrically connected to the electrode plate  54 . Upon a negative DC voltage being applied to the electrode plate  54 , a positive potential is produced on the rear surface of the wafer W, and a negative potential is produced on the front surface of the wafer. A potential difference thus arises between the electrode plate  54  and the rear surface of the wafer W, and hence the wafer W is attracted to and held on an upper surface of the electrostatic chuck  55  through a Coulomb force or a Johnsen-Rahbek force due to the potential difference. 
         [0053]    Moreover, an annular focus ring  57  is provided on an upper portion of the susceptor  45  so as to surround the wafer W attracted to and held on the electrostatic chuck  55 . The focus ring  57  is exposed to the processing space S′, and focuses plasma in the processing space S′ toward the front surface of the wafer W, thus improving the efficiency of the RIE processing. 
         [0054]    An annular coolant chamber  72  that extends, for example, in a circumferential direction of the susceptor  45  is provided inside the susceptor  45 . A coolant, for example cooling water or a Galden (registered trademark) fluid, at a predetermined temperature is circulated through the coolant chamber  72  via coolant piping  58  from a chiller unit (not shown). A processing temperature of the wafer W attracted to and held on the electrostatic chuck  55  is controlled through the temperature of the coolant. 
         [0055]    A plurality of heat-transmitting gas supply holes  59  are provided in a portion of the electrostatic chuck  55  on which the wafer W is attracted and held (hereinafter referred to as the “attracting surface”). The heat-transmitting gas supply holes  59  are connected to a heat-transmitting gas supply unit (not shown) by a heat-transmitting gas supply line  60 . The heat-transmitting gas supply unit supplies helium gas as a heat-transmitting gas via the heat-transmitting gas supply holes  59  into a gap between the attracting surface of the electrostatic chuck  55  and the rear surface of the wafer W. The helium gas supplied into the gap between the attracting surface of the electrostatic chuck  55  and the rear surface of the wafer W transmits heat from the wafer W to the susceptor  45  via the electrostatic chuck  55 . 
         [0056]    A plurality of pusher pins  61  are provided in the attracting surface of the susceptor  45  as lifting pins that can be made to project out from the electrostatic chuck  55 . The pusher pins  61  are connected to a motor (not shown) by a ball screw (not shown), and can be made to project out from the attracting surface of the susceptor  45  through rotational motion of the motor, which is converted into linear motion by the ball screw. The pusher pins  61  are housed inside the susceptor  45  when a wafer W is being attracted to and held on the attracting surface of the susceptor  45  so that the wafer W can be subjected to the RIE processing, and are made to project out from the electrostatic chuck  55  so as to lift the wafer W up away from the susceptor  45  when the wafer W is to be transferred out from the chamber  44  after having been subjected to the RIE processing. 
         [0057]    A gas introducing shower head  62  is disposed in a ceiling portion of the chamber  44  (the reaction chamber  48 ) such as to face the susceptor  45 . An upper radio frequency power source  64  is connected to the gas introducing shower head  62  via a matcher  63 . The upper radio frequency power source  64  supplies predetermined radio frequency electrical power to the gas introducing shower head  62 . The gas introducing shower head  62  thus acts as an upper electrode. The matcher  63  has a similar function to the matcher  53 , described earlier. 
         [0058]    The gas introducing shower head  62  has a ceiling electrode plate  66  having a large number of gas holes  65  therein, and an electrode support  67  on which the ceiling electrode plate  66  is detachably supported. A buffer chamber  68  is provided inside the electrode support  67 . A processing gas introducing pipe  69  is connected to the buffer chamber  68 . A processing gas supplied from the processing gas introducing pipe  69  into the buffer chamber  68  is supplied by the gas introducing shower head  62  into the chamber  44  (the reaction chamber  48 ) via the gas holes  65 . 
         [0059]    A transfer port  70  for the wafers W is provided in a side wall of the chamber  44  in a position at the height of a wafer W that has been lifted up from the susceptor  45  by the pusher pins  61 . The gate valve  20 , which is for opening and closing the transfer port  70 , is provided in the transfer port  70 . 
         [0060]    Radio frequency electrical power is supplied to the susceptor  45  and the gas introducing shower head  62  in the chamber  44  of the processing module  13  as described above so as to apply radio frequency electrical power into the processing space S′ between the susceptor  45  and the gas introducing shower head  62 , whereupon the processing gas supplied into the processing space S′ from the gas introducing shower head  62  is turned into high-density plasma, whereby ions and radicals are produced; the wafer W is subjected to the RIE processing by the ions and so on. 
         [0061]    The processing module  14  has a similar construction to the processing module  13 . Description of the construction of the processing module  14  is thus omitted. 
         [0062]    In the processing module  14 , a wafer W that has been subjected to the RIE processing in the processing module  13  is transferred into the chamber  44  and supported by the pusher pins  61 , and then oxygen (O 2 ) gas is introduced into the processing space S′ from the gas introducing shower head  62 . At this time, the pusher pins  61  support the wafer W in a state lifted up from the susceptor  45 . There is thus a space below the rear surface of the wafer W. 
         [0063]    Upon radio frequency electrical power being supplied to the susceptor  45  and the gas introducing shower head  62  so as to apply radio frequency electrical power into the processing space S′ between the susceptor  45  and the gas introducing shower head  62 , plasma is produced from the oxygen gas in the processing space S′, whereby oxygen radicals are produced. At this time, the oxygen radicals go round into the space below the rear surface of the wafer W, and hence the oxygen radicals decompose the CF-type protective film on the rear surface of the wafer W and thus remove the CF-type protective film (ashing processing). 
         [0064]    Note that in the processing module  14 , the CF-type protective film is removed by oxygen radicals, but alternatively fluorine radicals may be produced in the processing space S′, the CF-type protective film on the rear surface of the wafer W being decomposed and thus removed by the fluorine radicals, or ozone gas may be supplied into the processing space S′, the CF-type protective film being decomposed and thus removed by the ozone gas. 
         [0065]    Returning to  FIG. 1 , the substrate processing system  10  further has a system controller (not shown) that controls operation of the component elements of the substrate processing system  10 , for example the transfer module  11 , the processing modules  12  to  15 , and the loader module  16 , and an operation panel  71  that is disposed at one end of the loader module  16  in the longitudinal direction of the loader module  16 . 
         [0066]    The operation panel  71  has a display section comprised of, for example, an LCD (liquid crystal display), for displaying the state of operation of the component elements of the substrate processing system  10 . 
         [0067]    According to the substrate processing system  10  described above, a CF-type protective film is formed through CVD processing on the rear surface of each wafer W before the RIE processing is carried out, and then the CF-type protective film is removed from the rear surface of the wafer W through ashing processing after the RIE processing has been carried out. As a result, the CF-type protective film can be formed reliably, and can be removed reliably. Moreover, in the processing module  13 , the electrostatic chuck  55  contacts the CF-type protective film formed on the rear surface of each wafer W. The rear surface of the wafer W can thus be prevented from being scratched when the wafer W is attracted to the electrostatic chuck  55 , and moreover the adhesion between the wafer W and the electrostatic chuck can be improved, and hence the controllability of the temperature of the wafer W can be improved. 
         [0068]    In the substrate processing system  10 , the CF-type protective film is formed through CVD processing in the processing module  12 , and hence the processing module  12  is a vacuum-type processing apparatus. Here, the processing module  13  in which each wafer W is subjected to the RIE processing is also a vacuum-type processing apparatus, and the transfer module  11  is a vacuum-type substrate transferring apparatus, and hence the processing module  12  and the processing module  13  can be connected together via the transfer module  11 . As a result, the formation of the CF-type protective film on the rear surface of each wafer W and the RIE processing on the wafer W can be carried out one after the other smoothly. 
         [0069]    Moreover, in the substrate processing system  10 , the protective film is removed through ashing processing in the processing module  14 , and hence the processing module  14  is a vacuum-type processing apparatus. Here, the processing module  13  is also a vacuum-type processing apparatus, and the transfer module  11  is a vacuum-type substrate transferring apparatus, and hence the processing module  13  and the processing module  14  can be connected together via the transfer module  11 . As a result, the RIE processing on each wafer W and the removal of the CF-type protective film can be carried out one after the other smoothly. 
         [0070]    Note that in the substrate processing system  10  described above, a CF-type protective film is formed through CVD processing in the processing module  12 , but the protective film is not limited to being a CF-type protective film. Moreover, the method of forming the protective film is not limited to being CVD processing, but rather any vapor deposition may be used, for example PVD (physical vapor deposition) processing. 
         [0071]    Next, a substrate processing system according to a second embodiment of the present invention will be described. 
         [0072]    In the present embodiment, the construction and operation are basically the same as in the first embodiment described above, only the protective film forming apparatus and the protective film removing apparatus differing to in the first embodiment. Description of features of the construction that are the same as in the first embodiment is thus omitted, only features of the operation that differ to in the first embodiment being described below. 
         [0073]      FIG. 4  is a plan view schematically showing the construction of the substrate processing system according to the present embodiment. 
         [0074]    As shown in  FIG. 4 , in the substrate processing system  80 , in addition to the lock modules  17  and  18  and the FOUP mounting stages  31 , the loader module  16  (atmospheric-type substrate transferring apparatus) has connected thereto, via a wafer inverting unit  83  that inverts each wafer W, a coating unit  81  (protective film forming apparatus) for forming a protective film made of a photosensitive resin on the rear surface of each wafer W, and further has connected thereto a cleaning unit  82  for removing the protective film from the rear surface of each wafer W. Specifically, the coating unit  81  is disposed at one end of the loader module  16  in the longitudinal direction of the loader module  16 , and the cleaning unit  82  is disposed alongside the three FOUP mounting stages  31 . In the substrate processing system  80 , each wafer W is transferred around in the order coating unit  81 , processing module  13 , cleaning unit  82 . 
         [0075]      FIG. 5  is a sectional view schematically showing the construction of a coating unit that forms the protective film made of the photosensitive resin on the rear surface of each wafer. 
         [0076]    As shown in  FIG. 5 , the coating unit  81  is comprised of a chamber  84  as a box-shaped housing chamber in which a wafer W is housed, a spinning chuck  86  disposed in a central portion of the chamber  84 , an annular cup  85  disposed such as to surround the spinning chuck  86 , and a coating liquid ejecting apparatus  87 . 
         [0077]    The spinning chuck  86  is comprised of a stage  88  on which the wafer W is mounted, and a shaft  89  that extends downwards from a lower portion of the stage  88 . The shaft  89  supports the stage  88  such that an upper surface of the stage  88  is horizontal. The stage  88  has a plurality of vacuum suction holes (not shown) provided in the upper surface thereof. The wafer W mounted on the stage  88  is attracted by vacuum suction to the upper surface of the stage  88  by the vacuum suction holes. The stage  88  also has a cushioning film (not shown) made of a resin on the upper surface thereof. Here, each wafer W is inverted by the wafer inverting unit  83  before being transferred into the chamber  84 . The front surface of the wafer W is thus attracted by vacuum suction to the upper surface of the stage  88  via the cushioning film, and hence there is no destruction of the shape of wiring grooves or via holes formed on the front surface of the wafer W. 
         [0078]    Moreover, the rear surface of the wafer W is exposed to the interior of the chamber  84 . The shaft  89  is rotated about a central axis of the shaft by a motor (not shown). The wafer W attracted by vacuum suction to the upper surface of the stage  88  thus rotates in a horizontal plane. Moreover, the shaft  89  can be raised and lowered by an air cylinder (not shown). 
         [0079]    The cup  85  is an annular vessel, and has in an upper portion thereof an opening  90  provided around the whole circumference thereof. When the wafer W attracted by vacuum suction to the stage  88  is lowered, a peripheral portion of the wafer W is housed in the opening  90 . The cup  85  also has an excess liquid discharge pipe  91  in a bottom portion thereof. 
         [0080]    The coating liquid ejecting apparatus  87  has a nozzle  92  disposed facing the wafer W attracted by vacuum suction to the upper surface of the stage  88 , a coating liquid supply pipe  93  that connects the nozzle  92  to a coating liquid supply apparatus (not shown) that supplies a coating liquid, a nozzle holder  94  to which the nozzle  92  is detachably attached, and a nozzle scanning arm  95  having the nozzle holder  94  on a distal end thereof. The nozzle scanning arm  95  is attached to an upper end of a vertical supporting member  97  that can be moved horizontally through a guide rail  96  that is installed on the bottom portion of the chamber  84 . The nozzle scanning arm  95  can thus be moved in a depth direction in  FIG. 5  together with the vertical supporting member  97 . 
         [0081]    A transfer port  98  for the wafers W is provided in a side wall of the chamber  84  in a position at the height of a wafer W that has been lifted up by the spinning chuck  86 . 
         [0082]    In the coating unit  81 , the nozzle  92  ejects the coating liquid, for example a photosensitive resin liquid, toward the rear surface of the wafer W, which rotates in a horizontal plane. Upon the ejected coating liquid reaching the rear surface of the wafer W, the coating liquid spreads out uniformly over the rear surface of the wafer W through centrifugal force. As a result, the photosensitive resin is coated uniformly over the rear surface of the wafer W (spin coating processing). At this time, excess photosensitive resin liquid is caught by the cup  85 , and discharged to the outside via the excess liquid discharge pipe  91 . 
         [0083]    The coating unit  81  also has a UV lamp (not shown) or the like that irradiates the rear surface of the wafer W with UV light, thus exposing and hence curing the photosensitive resin that has been coated onto the rear surface of the wafer W. As a result, a protective film is formed on the rear surface of the wafer W. 
         [0084]    An example of the photosensitive resin used in the coating unit  81  is a resin containing a cellulose derivative having carboxyl groups and having an acid value of 30 to 220 mgKOH/g. 
         [0085]    The coating liquid coated onto the rear surface of each wafer W in the coating unit  81  may alternatively be a thermosetting resin liquid, for example a polyimide-containing resin liquid. In this case, instead of the UV lamp, the coating unit  81  has a heater for heating the rear surface of the wafer W. 
         [0086]    The wafer W having the protective film formed on the rear surface thereof by the coating unit  81  is inverted by the wafer inverting unit  83  after being transferred out from the chamber  84 , and is then further transferred by the loader module  16 . 
         [0087]      FIG. 6  is a sectional view schematically showing the construction of a cleaning unit that removes the protective film made of the photosensitive resin from the rear surface of each wafer. 
         [0088]    As shown in  FIG. 6 , the cleaning unit  82  is comprised of a chamber  99  as a box-shaped housing chamber in which a wafer W is housed, a stage  101  that is disposed on a bottom portion  100  of the chamber  99 , a head  102  that is disposed facing the stage  101  separated from the stage  101  by a predetermined gap, and a discharge pipe  103  that discharges a washing liquid or the like, described below, out of the chamber  99 . 
         [0089]    The stage  101  is a cylindrical projecting object, and has a plurality of washing liquid jetting portions  104  in an upper surface thereof. A plurality of lifting pins  105  are disposed in the upper surface of the stage  101 . The lifting pins  105  contact the rear surface of a wafer W that has been transferred into the chamber  99 , and thus support the wafer W. The lifting pins  105  can be made to project out from the upper surface of the stage  101 , whereby the lifting pins  105  can move the wafer W in an up/down direction in  FIG. 6 . When the protective film on the rear surface of a wafer W is to be removed, the lifting pins  105  move the wafer W so that the wafer W is positioned at an intermediate point between the head  102  and the stage  101 , and when the wafer W is to be transferred in or out, the lifting pins  105  move the wafer W so that the wafer W is positioned at the height of a wafer W transfer port  106  provided in a side wall of the chamber  99 . Moreover, the head  102  is comprised of a substantially disk-shaped member, and has a plurality of washing liquid jetting portions  107  in a lower surface thereof. 
         [0090]    In the cleaning unit  82 , the washing liquid is jetted out from the washing liquid jetting portions  104  facing the rear surface of the wafer W supported by the lifting pins  105 , and moreover the washing liquid is jetted out from the washing liquid jetting portions  107  facing the front surface of the wafer W. Examples of the washing liquid are an alkaline aqueous solution, a hydrogen peroxide aqueous solution, and sulfuric acid solution. The washing liquid dissolves and thus removes a resist film formed on the front surface of the wafer W, and moreover dissolves and thus removes the protective film made of the photosensitive resin formed on the rear surface of the wafer W (wet washing processing). 
         [0091]    According to the substrate processing system  80  described above, a protective film made of a photosensitive resin is formed through spin coating processing (coating processing) on the rear surface of each wafer W before the RIE processing is carried out, and then the protective film is removed from the rear surface of the wafer W by being dissolved by a washing liquid after the RIE processing has been carried out. As a result, the protective film made of the photosensitive resin can be formed easily and reliably, and can be removed easily and reliably. Moreover, in the processing module  13 , the electrostatic chuck  55  contacts the protective film made of the photosensitive resin formed on the rear surface of each wafer W. The rear surface of the wafer W can thus be prevented from being scratched when the wafer W is attracted to the electrostatic chuck  55 , and moreover the adhesion between the wafer W and the electrostatic chuck can be improved, and hence the controllability of the temperature of the wafer W can be improved. 
         [0092]    In the substrate processing system  80 , foreign matter, for example fine particles due to photosensitive resin being scattered from the wafer W, may be produced during the spin coating processing in the coating unit  81 . However, the coating unit  81  is connected to the loader module  16  and hence is not connected to the transfer module  11  directly, and thus foreign matter produced in the coating unit  81  can be prevented from infiltrating into the processing module  13  used as the etching apparatus via the transfer module  11 . 
         [0093]    Moreover, in the substrate processing system  80 , when the protective film is dissolved and thus removed by the washing liquid in the cleaning unit  82 , the washing liquid may be scattered from the cleaning unit  82 . However, the cleaning unit  82  is connected to the loader module  16  and hence is not connected to the transfer module  11  directly, and thus the washing liquid and the like can be prevented from infiltrating into the processing module  13  via the transfer module  11 . 
         [0094]    Note that in the substrate processing system  80  described above, the protective film made of the photosensitive resin formed on the rear surface of each wafer W may alternatively be removed through ashing processing. In this case, the removal of the protective film is carried out in the processing module  14 . 
         [0095]    Moreover, the substrate processing system  80  need not have the wafer inverting unit  83 . In this case, the coating unit preferably has a nozzle that sprays the photosensitive resin liquid toward the rear surface of each wafer W from below the wafer W, which rotates in a horizontal plane. The photosensitive resin liquid is sticky, and hence becomes attached to the rear surface of the wafer W, and then spreads out uniformly over the rear surface of the wafer W through centrifugal force. 
         [0096]    Furthermore, instead of forming the protective film on the rear surface of each wafer W through spin coating processing as described above, the protective film may be formed by sticking a resin sheet onto the rear surface of each wafer W. 
         [0097]    Moreover, the substrates subjected to the etching processing in the substrate processing system according to each of the embodiments described above are not limited to being semiconductor wafers, but rather may be any of various substrates used in LCDs (liquid crystal displays), FPDs (flat panel displays) or the like, or photomasks, CD substrates, printed substrates, or the like. 
         [0098]    The above-described embodiments are merely exemplary of the present invention, and are not be construed to limit the scope of the present invention. 
         [0099]    The scope of the present invention is defined by the scope of the appended claims, and is not limited to only the specific descriptions in this specification. Furthermore, all modifications and changes belonging to equivalents of the claims are considered to fall within the scope of the present invention.