Abstract:
A substrate coated with a coating solution, for example, a resist solution is heated at a predetermined temperature, thereafter putted in a non-heated state, and then heated at a second predetermined temperature. Alternatively, a heating process in which a substrate coated with a resist solution is heated and a non-heated process in which the substrate is putted in a non-heated state are repeated a plurality of times. The adoption of the above treating methods can prevent the occurrence of transfer which is an index of ununiformity of film thickness of a resist solution and the like and change in line width of a circuit pattern, thus improving yield in substrate treatment.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention relates to a substrate treating method for drying a coating solution on a substrate by heating when predetermined treatment is performed for the substrate coated with the coating solution such as an LCD substrate, a semiconductor wafer or the like.  
         BACKGROUND OF THE INVENTION  
         [0002]    In the fabrication of a liquid-crystal display (LCD), for example, a circuit pattern is formed by so-called photolithography technology in which a rectangular glass LCD substrate (referred to as a substrate hereinafter) is coated with a coating solution such as a photo-resist solution to form a resist film and in which the resist film is exposed correspondingly to the circuit pattern and developed.  
           [0003]    In the process of coating a resist solution, in order to enhance the fixedness of the resist, the rectangular substrate is given hydrophobic treatment in an adhesion treating unit and cooled in a cooling unit, and then carried in a resist coating unit.  
           [0004]    In the resist coating unit, while the rectangular substrate is rotated in the state of being held on a spin chuck, a resist solution is supplied to the central portion of the surface of the substrate from a nozzle provided above the central portion and spread by centrifugal force due to the rotation of the substrate, whereby the entire surface of the substrate is coated with a resist film.  
           [0005]    After an excess resist at the periphery of the substrate is removed, the substrate coated with the resist solution is carried in a heating unit to undergo pre-baking treatment. In the heating unit, in order to prevent direct contact of a heating plate and the substrate, a so-called proximity type is often adopted in which the substrate received by lifting pins is mounted on securing pins of the heating plate and heated by heat radiated from the heating plate.  
           [0006]    Subsequently, the substrate is cooled in a cooling unit and carried to an aligner where a predetermined pattern is exposed. Thereafter, the substrate is developed and given post-baking treatment, thereby forming a predetermined resist pattern.  
           [0007]    In the above coating and developing unit, however, there are some cases where shapes of the lifting pins, securing pins, vacuum grooves, or the like are transferred to the substrate after the substrate coated with the resist solution receives pre-baking treatment and the like, or after the substrate is exposed and developed.  
           [0008]    The transfer of the lifting pins and the like is caused specifically by the film thickness of the resist solution coated on the substrate being changed correspondingly to the shapes of the lifting pins and the like after pre-baking treatment, and by the line width of the circuit pattern formed on the substrate being changed according to the shapes of the lifting pins and the like after exposure and development. Even when no transfer is found after pre-baking treatment, there are cases where transfer occurs after development.  
           [0009]    It is supposed that such transfer is caused by a sensitized resist solution being used recently and by the line width of a circuit pattern formed on an LCD substrate being 3 μm which is smaller than ever, but the cause thereof is not determined in detail. Hence, success is not achieved yet in preventing such transfer.  
           [0010]    As described above, however, such transfer of the lifting pins and the like corresponds to the ununiformity of the film thickness of the resist solution and a change in line width of the circuit pattern. Thus, it is requested to prevent to the utmost such transfer from occurring on the substrate in the coating and developing process of the LCD substrate.  
         SUMMARY OF THE INVENTION  
         [0011]    The present invention is made in view of the aforesaid disadvantage, and its object is to provide a substrate treating method capable of preventing transfer which is indexes of ununiformity of film thickness of a resist solution and change in line width of a circuit pattern.  
           [0012]    In order to solve the above disadvantage, according to the first aspect of the present invention, a substrate treating method for performing predetermined treatment for a substrate coated with a coating solution including the steps of (a) heating the substrate coated with the coating solution at a first predetermined temperature, (b) lowering the temperature of the substrate by positively cooling the substrate and/or by naturally releasing the heat thereof after the step (a), and (c) heating the substrate at a second predetermined temperature after the step (b) is provided.  
           [0013]    In the non-heated step (b) in the substrate treating method according to the first aspect, it is possible that the substrate is carried out of a heating unit, that is, the temperature of the substrate is lowered by natural heat release and/or that the substrate is positively cooled by a cooling unit.  
           [0014]    Further, preferably the first predetermined temperature in the heating step (a) is lower than the second predetermined temperature in the heating step (c). Therefore, when the heating step (a) and the heating step (c) are performed in the same treating unit, preferably a space between the substrate and a heating plate in the heating step (a) is larger than that in the heating step (c).  
           [0015]    According to the second aspect of the present invention, a substrate treating method for performing predetermined treatment for substrates coated with a coating solution including the steps of (a) heating the substrates coated with the coating solution one by one at a first predetermined temperature, (b) lowering the temperature of the substrates by positively cooling the substrates and/or by naturally releasing the heat thereof one by one after the step (a), (c) heating the substrates one by one at a second predetermined temperature after the step (b), (d) lowering the temperature of the substrates by positively cooling the substrates and/or by naturally releasing the heat thereof one by one after the step (c), and (e) heating the substrates one by one or plural substrates at a time at a third predetermined temperature after the step (d), is provided.  
           [0016]    In the non-heated step (b) and the non-heated step (d) in the substrate treating method according to the second aspect, it is possible that the substrate is carried out of the heating unit, that is, the temperature of the substrate is lowered by natural heat release and/or that the substrate is positively cooled by the cooling unit.  
           [0017]    Further, preferably the first predetermined temperature in the heating step (a) is lower than the second predetermined temperature in the heating step (c), and preferably the second predetermined temperature in the heating step (c) is lower than the third predetermined temperature in the heating step (e).  
           [0018]    Furthermore, in the heating step (e), similarly to the heating steps (a) and (c), the substrates may be heat-treated one by one, or the plural substrates may be concurrently heat-treated in one treating unit, for example, a heating furnace or the like in order to enhance throughput of treatment.  
           [0019]    According to the substrate treating method in accordance with the first and the second aspects, the heating step (a) can be performed before exposing the substrate, and the heating step (c) can be performed after exposing the substrate.  
           [0020]    Moreover, predetermined treatment for the substrate, for example, drying treatment while supplying gas, drying treatment under reduced pressure, gelling treatment of a coating film, exchanging treatment of a coating film solvent after coating the solvent, removing treatment for removing at least a part of a coating film, or the like may be performed before the heating step (a) or between the heating step (a) and the heating step (c).  
           [0021]    According to the third aspect of the present invention, a substrate treating method for performing predetermined treatment for a substrate coated with a coating solution including the steps of (a) heating the substrate coated with the coating solution, and (b) putting the substrate in a non-heated state after said step (a), with the steps (a) and (b) being repeated a plurality of times, is provided.  
           [0022]    In the non-heated step (b) in the substrate treating method according to the third aspect, it is possible that the substrate is carried out of the heating unit, that is, the temperature of the substrate is lowered by natural heat release and/or that the substrate is positively cooled by the cooling unit.  
           [0023]    With the repetition of the heating process and the non-heated process a plurality of times, it is preferable that the treating temperature in the heating process is set at higher temperature.  
           [0024]    Further, predetermined treatment for the substrate, for example, drying treatment while supplying gas, drying treatment under reduced pressure, gelling treatment of a coating film, exchanging treatment of a coating film solvent after coating the solvent, removing treatment for removing at least a part of a coating film, or the like may be performed before the heating step (a) or between the heating step (a) and the non-heated step (b).  
           [0025]    According to the first and the second aspects of the present invention, the substrate coated with the coating solution is heated at the first predetermined temperature, and after the above heating, through the non-heated step (b), the substrate is heated at the second predetermined temperature. According to the third aspect, the step of heating the substrate coated with the coating solution and the step of putting the substrate in a non-heated state are repeated a plurality of times, thus gradually releasing a solvent in the coating solution, promoting drying of the coating solution without exerting a bad influence on the coating film, and effectively preventing the occurrence of transfer on the substrate.  
           [0026]    Further, in the first and the second aspects, a heating temperature in the heating step (a) is made lower than that in the heating step (c), thus holding down abrupt vaporization of the solvent in the coating solution to provide a more appropriate dried state and more effectively preventing the occurrence of transfer. The above difference in temperature can be realized by providing a low-temperature heating unit and a high-temperature heating unit both of which are different in set temperature, and by setting a space between the substrate and a heating plate in the heating step (a) larger than that in the heating step (c). 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0027]    [0027]FIG. 1 is a plane view showing a coating and developing system of an LCD substrate to which the present invention is applied;  
         [0028]    [0028]FIG. 2 is a schematic plane view showing the entire configurations of a resist coating unit (COT) and an edge remover (ER);  
         [0029]    [0029]FIG. 3 is a schematic sectional view of a heating unit (HP);  
         [0030]    [0030]FIG. 4( a ) and FIG. 4( b ) are views showing the state that a substrate G is heated by the heating unit (HP) shown in FIG. 3;  
         [0031]    [0031]FIG. 5 is a plane view showing a part of a coating and developing system of an LCD substrate according to another embodiment;  
         [0032]    [0032]FIG. 6 is a schematic sectional view of a drying unit used in the system in FIG. 5;  
         [0033]    [0033]FIG. 7( a ) and FIG. 7( b ) are plane views respectively of the upper tier and the lower tier of a coating film forming system (SOD system) according to still another embodiment of the present invention;  
         [0034]    [0034]FIG. 8 is a side elevational view of the coating film forming system (SOD system) shown in FIG. 7;  
         [0035]    [0035]FIG. 9 is a side elevational view showing two treating unit groups, in each of which a plurality of treating units are multi-tiered, provided in the coating film forming system (SOD system) shown in FIG. 7;  
         [0036]    [0036]FIG. 10 is a sectional view schematically showing a low-viscosity coating unit (SCT);  
         [0037]    [0037]FIG. 11 is a sectional view schematically showing an aging unit (DAC);  
         [0038]    [0038]FIG. 12 is a sectional view schematically showing a solvent exchange unit (DSE);  
         [0039]    [0039]FIG. 13 is a plane view schematically showing a DCC treating unit; and  
         [0040]    [0040]FIG. 14 is a sectional view schematically showing the DCC treating unit shown in FIG. 13. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0041]    Preferred embodiments of the present invention will be described below based on examples of a substrate treating method applied to a substrate treating apparatus used for a resist treating system for forming a coating film such as a photo resist on a surface of a glass substrate G for a liquid-crystal display (LCD) (referred to as “a substrate G” hereinafter. Incidentally, it goes without saying that the present invention is not limited to a glass substrate but applicable to a plate-shaped substrate such as a semiconductor wafer.)  
         [0042]    Next, an embodiment of the present invention will be described in detail with reference to the attached drawings.  
         [0043]    [0043]FIG. 1 is a plane view showing a coating and developing system of an LCD substrate as an example of a substrate treating apparatus to which the present invention is applied.  
         [0044]    The coating and developing system includes a cassette station  1  for mounting a cassette C for housing a plurality of substrates G, a treatment section  2  provided with a plurality of treating units for performing a series of treatment including resist coating and developing for the substrate G, and an interface section  3  for sending and receiving the substrate G to/from an aligner (not shown), the cassette station  1  and the interface section  3  being arranged respectively at either end of the treatment section  2 .  
         [0045]    The cassette station  1  includes a carrier section  10  for carrying the substrate G between the cassette C and the treatment section  2 . In the cassette station  1 , the substrate G is carried in/out of the cassette C. The carrier section  10  includes a carrier mechanism  11  which is movable on a carrier path  10   a  provided along the direction of disposition of the cassettes C, and the substrate G is carried between the cassettes C and the treatment section  2  by means of the carrier mechanism  11 .  
         [0046]    The treatment section  2  is divided into a front section  2   a , a middle section  2   b , and a rear section  2   c , respectively having carrier paths  12 ,  13 , and  14  in the center thereof. Treating units are disposed at both sides of each of the carrier paths. Relay sections  15  and  16  are provided respectively between the front section  2   a  and the middle section  2   b , and between the middle section  2   b  and the rear section  2   c.    
         [0047]    The front section  2   a  includes a main carrier device  17  movable along a carrier path  12 . Two scrubbing units (SCR)  21   a  and  21   b  are disposed at one side of the carrier path  12 , and an ultraviolet-light irradiating and cooling unit (UV/COL)  25 , respectively vertically two-tiered heating units (HP)  26  and cooling units (COL)  27  are disposed at the other side of the carrier path  12 .  
         [0048]    The middle section  2   b  includes a main carrier device  18  movable along a carrier path  13 . On one side of the carrier path  13 , a resist coating unit (COT)  22  and an edge remover (ER)  23  for removing a resist at the peripheral portion of the substrate G are integrally provided, and on the other side thereof, two-tiered heating units (HP)  28 , a heating and cooling unit (HP/COL)  29  composed of a heating unit and a cooling unit vertically tiered, and an adhesion treating and cooling unit (AD/COL)  30  in which an adhesion treating unit and a cooling unit are vertically tiered are arranged.  
         [0049]    Further, the rear section  2   c  includes a main carrier device  19  movable along a carrier path  14 . On one side of the carrier path  14 , three developing units  24   a ,  24   b , and  24   c  are disposed, and on the other side thereof, vertically two-tiered heating units  31 , two heating and cooling units (HP/COL)  32  and  33  each composed of a heating unit and a cooling unit vertically tiered are disposed.  
         [0050]    The treatment section  2  has a structure in which only spinner-system units such as the scrubbing unit  21   a , the resist coating unit  22 , and the developing unit  24   a  are arranged on one side of each carrier path and only heat-system treating units such as the heating unit and the cooling unit are arranged on the other side thereof.  
         [0051]    A chemicals feed unit  34  is disposed at a portion on the side of the arrangement of spinner-system units of each of the relay sections  15  and  16 , and moreover a space  35  sufficient to take the main carrier device in and out is provided thereat.  
         [0052]    The main carrier device  17  has a function of sending and receiving the substrate G to/from an arm of the carrier mechanism  11 , carrying the substrate G in/out of respective treating units in the front section  2   a , and sending and receiving the substrate G to/from the relay section  15 . The main carrier device  18  has a function of sending and receiving the substrate G to/from the relay section  15 , carrying the substrate G in/out of respective treating units in the middle section  2   b , and sending and receiving the substrate G to/from the relay section  16 . The main carrier device  19  has a function of sending and receiving the substrate G to/from the relay section  16 , carrying the substrate G in/out of respective treating units in the rear section  2   c , and sending and receiving the substrate G to/from the interface section  3 . Incidentally, the relay sections  15  and  16  function also as cooling plates.  
         [0053]    The interface section  3  includes an extension  36  for temporarily holding the substrate when the substrate is sent and received to/from the treatment section  2 , two buffer stages  37  for placing a buffer cassette on both sides of the extension  36 , and a carrier mechanism  38  for carrying the substrate G in/out of the aligner (not shown). The carrier mechanism  38  has a carrier arm  39  movable on a carrier path  38   a  provided along the direction of disposition of the extension  36  and the buffer stages  37 . The substrate G is carried between the treatment section  2  and the aligner by means of the carrier arm  39 .  
         [0054]    The respective treating units are put together to be integrated as above, thereby saving space and promoting efficiency of treatment.  
         [0055]    In the coating and developing system structured as above, the substrate G in the cassette C is carried to the treatment section  2 . In the treatment section  2 , first in the front section  2   a , the substrate G is given surface reforming and cleaning treatment and thereafter cooling treatment in the ultraviolet-light irradiating and cooling unit (UV/COL)  25 , subsequently is scrubbed in the scrubbing units (SCR)  21   a  and  21   b , dried by heating in one of the heating units (HP)  26 , and then cooled in one of the cooling units (COL)  27 .  
         [0056]    Thereafter, the substrate G is carried to the middle section  2   b . In order to improve the fixedness of a resist, the substrate G is given hydrophobic treatment (HMDS treatment) in the adhesion treating unit (AD) in the upper tier of the unit  30 , cooled in the cooling unit (COL), and then coated with a resist in the resist coating unit (COT)  22 . Subsequently, an excess resist on the periphery of the substrate G is removed in the edge remover (ER)  23 . Then, the substrate G is pre-baked in one of the heating units (HP) in the middle section  2   b  and cooled in the cooling unit (COL) in the lower tier of the unit  29  or  30 . In the present embodiment, the above pre-baking treatment is performed at predetermined timing a plurality of times as described later.  
         [0057]    Later, the substrate G is carried from the relay section  16  to the aligner via the interface section  3  by means of the main carrier device  19  and a predetermined pattern is exposed in the aligner. The substrate G is brought in again via the interface section  3  and developed in any one of the developing units (DEV)  24   a ,  24   b , and  24   c  to thereby form a predetermined circuit pattern. The developed substrate G is given post-baking treatment in any one of the heating units (HP) in the rear section  2   c , cooled in the cooling unit (COL), and then housed in a predetermined cassette C on the cassette station  1  by means of the main carrier devices  19 ,  18 , and  17  and the carrier mechanism  11 .  
         [0058]    Next, the resist coating unit (COT)  22  and the edge remover (ER)  23  provided in the coating and developing system according to the present embodiment will be described. FIG. 2 is a schematic plane view showing the entire configurations of the resist coating unit (COT) and the edge remover (ER).  
         [0059]    As shown in FIG. 2, the resist coating unit (COT)  22  and the edge remover (ER)  23  are integrally provided side by side on the same stage. The substrate G coated with the resist in the resist coating unit (COT)  22  is carried to the edge remover (ER)  23  by means of a pair of carrier arms  41  movable along guide rails  42 . Incidentally, an opening  22   a  for carrying the substrate G in by the main carrier device  18  is formed in a face at the carrier path  13  side of the resist coating unit (COT)  22 , and an opening  23   a  for carrying the substrate G out by the main carrier device  18  is formed in a face at the carrier path  13  side of the edge remover (ER)  23 .  
         [0060]    The resist coating unit (COT)  22  includes a horizontally rotatable spin chuck  51  for adsorbing and holding the substrate G, a bottomed cylindrical rotating cup  52  enclosing an upper end portion of the spin chuck  51  and surrounding the substrate G adsorbed and held by the spin chuck  51 , the upper end portion of the rotating cup being opened, a lid body (not shown) being put on the upper end opening of the rotating cup  52 , a coater cup  53  fixedly disposed in such a manner to enclose the outer periphery of the rotating cup  52  for preventing a resist from being scattered when the resist is coated, and a hollow ring-shaped drain cup  54  disposed to surround the coater cup  53 . When a resist is dropped, as is described later, with the lid body being taken off from the rotating cup  52 , the substrate G together with the spin chuck  51  is rotated at low speed by means of a rotating mechanism not shown and concurrently the rotating cup  52  is rotated. When the resist is spread, with the rotating cup  52  being covered with the lid body not shown, the substrate G together with the spin chuck  51  is rotated at high speed by means of the rotating mechanism not shown and concurrently the rotating cup  52  is rotated.  
         [0061]    The resist coating unit (COT)  22  has an arm  55  provided with a jet head  56  for supplying a resist solution and a solvent to the substrate G at the front end thereof. The arm  55  can rotate on a shaft  55   a . When a resist is coated, the jet head  56  is located above the substrate G adsorbed by the spin chuck  51 , and when the substrate G is carried, the jet head  56  is placed at a stand-by position outside the drain cup  54  as shown in the drawing. The jet head  56  is provided with a resist nozzle  57  for discharging a resist solution and a solvent nozzle  58  for discharging a solvent such as a thinner. The resist nozzle  57  is connected to a resist feed element (not shown) through a resist feed pipe (not shown), and the solvent nozzle  58  is connected to a solvent feed element (not shown) through a solvent feed pipe (not shown).  
         [0062]    The edge remover (ER)  23  is provided with a mounting table  61 , on which the substrate G is mounted. Four remover heads  62  for removing an excess resist solution from the edges of four sides of the substrate G are provided on four sides of the substrate G respectively. Each remover head  62  has a nearly U-shaped cross-sectional face so as to discharge a thinner from the inside thereof and is moved along four sides of the substrate G by means of a moving mechanism (not shown). Thus, each remover head  62  can remove the excess resist adhering to the edges of four sides of the substrate G while moving along each side of the substrate G and discharging a thinner.  
         [0063]    As to the resist coating unit (COT)  22  and the edge remover (ER)  23  which are integrally structured as above, first in the resist coating unit (COT)  22 , the substrate G together with the spin chuck  51  and the rotating cup  52  is rotated, the arm  55  is rotated so that the jet head  56  is located above the center of the substrate G, and a thinner is supplied to the center of the surface of the substrate G from the solvent nozzle  58 .  
         [0064]    Subsequently, with the substrate G being rotated, a resist is dropped on the center of the substrate G from the resist nozzle  57  to spread over the substrate G. Then, the rotating cup  52  is covered with the lid body not shown, and the rotational frequency of the substrate G is increased to thereby adjust the thickness of a resist film.  
         [0065]    The substrate G thus resist-coated is carried from the spin chuck  51  to the edge remover (ER)  23  and mounted on the mounting table  61  by the carrier arm  41 . In the edge remover (ER)  23 , the four remover heads  62  move along the respective sides of the substrate G, and the excess resist adhering to the edges of four sides of the substrate G is removed by the discharged thinner.  
         [0066]    Next, the heating unit (HP) will be described with reference to FIGS.  3 ,  4 ( a ), and  4 ( b ). FIG. 3 is a schematic sectional view of the heating unit (HP), and FIGS.  4 ( a ) and  4 ( b ) are views showing the state that the substrate G is heated by the heating unit (HP) shown in FIG. 3.  
         [0067]    The heating unit (HP) ( 28 ,  29 ) has a cover  71  which can freely go up and down as shown in FIG. 3. A heating plate  72  for heating the substrate G is placed with the face thereof being horizontal under the cover  71 . A heater (not shown) is attached to the heating plate  72 , whereby the heating plate  72  can be set at a desired temperature.  
         [0068]    Provided on the surface of the heating plate  72  are a plurality of securing pins  73 , by which the substrate G is held. Namely, a proximity type is adopted, in which direct contact of the heating plate  72  and the substrate G is avoided and the substrate G is heated by heat radiated from the heating plate  72 . Thus, contamination of the substrate G caused by the heating plate  72  is prevented.  
         [0069]    A plurality of lifting pins  75  which go through a plurality of holes of the heating plate  72  are provided so as to freely go up and down. Lower portions of the lifting pins  75  are supported by a supporting member  76 . The supporting member  76  is structured to be raised and lowered by a raising and lowering mechanism  77 . Thus, when the supporting member  76  is raised by the raising and lowering mechanism  77 , the lifting pins  75  are raised to receive the carried substrate G, subsequently lowered to place the substrate G on the securing pins  73  of the heating plate  72 , and after heat treatment, raised again to lift the substrate G to a position for carrying the substrate G out.  
         [0070]    In the present embodiment, the substrate G which is already coated with the resist solution and given end face treatment undergoes a first heating process and a second heating process with a non-heated process therebetween in the heating unit (HP) ( 28 ,  29 ).  
         [0071]    In the first heating process, as shown in FIG. 4( a ), the substrate G is supported by the lifting pins  75  and heated at a relatively lower temperature with a distance between the substrate G and the heating plate  72  of d 1 =3 mm to 5 mm, for example, the substrate and the heating plate being relatively apart from each other. Heating conditions under this situation are, for example, a heating temperature (a first predetermined temperature) of 60° C. to 70° C. and a heating time of about 60 seconds.  
         [0072]    In the non-heated process after the above first heating process, the substrate G is taken out of the heating unit (HP), and thereafter the substrate G is left in a non-heated state and naturally cooled by natural heat release, or positively cooled by the cooling unit (COL) shown in FIG. 1. Specifically, the substrate G may be taken out of the heating unit (HP) ( 28 ,  29 ) and left as it is, being exposed to the air without positively being heated, or may be carried from the heating unit (HP) ( 28 ,  29 ) to the cooling unit (COL) and positively cooled at a predetermined temperature.  
         [0073]    In the second heating process after the above non-heated process, as shown in FIG. 4( b ), the substrate G is supported by the lifting pins  75  and heated at a relatively higher temperature with a distance between the substrate G and the heating plate  72  of d 2 =0.2 mm, the substrate and the heating plate being relatively close to each other. In this situation, the heating temperature (a second predetermined temperature) is 100° C. to 120° C. and the heating time is about 100 seconds.  
         [0074]    As described above, the substrate G coated with the resist solution is heated at 60° C. to 70° C. (the first predetermined temperature). After the above heating, the substrate G naturally releases heat in a non-heated state or cooled, and after the natural heat release or the cooling, heated at 100° C. to 120° C. (the second predetermined temperature). Therefore, the relatively large-sized rectangular LCD substrate G is heated, naturally releases heat or is cooled, and heated, whereby a solvent such as a thinner in the resist solution is gradually released. According to the results of experiments, drying of the resist can be promoted without exerting a bad influence on the resist, and the occurrence of transfer on the substrate G can be effectively prevented.  
         [0075]    It should be mentioned that the first and the second temperatures, heating times and the like are not limited to the above values. It is preferable, however, that the first heating temperature (the first predetermined temperature) is lower than the second heating temperature (the second predetermined temperature).  
         [0076]    Further, in the present embodiment, heating processes and non-heated processes may be repeated a plurality of times, for example, a heating process→a non-heated process→a heating process→a non-heated process . . . . Also in this case, the relatively large-sized rectangular LCD substrate G is repeatedly heated and naturally cooled by natural heat release or positively cooled, whereby a solvent such as a thinner in the resist solution is gradually released. Thus, drying of the resist can be promoted without exerting a bad influence on the resist, and the occurrence of transfer on the substrate G can be effectively prevented.  
         [0077]    Furthermore, from the viewpoint of preventing transfer after development, it is possible that the substrate G is cooled after the first heating process and that the second heating process is performed after exposure. Also in this case, drying of the resist can be promoted before development, and the occurrence of transfer after development can be effectively prevented.  
         [0078]    Next, another embodiment of the present invention will be described with reference to FIGS. 5 and 6. FIG. 5 is a plane view showing a part of a coating and developing system of an LCD substrate according to another embodiment, and FIG. 6 is a schematic sectional view of a drying unit.  
         [0079]    In this embodiment, as shown in FIG. 5, a drying unit  80  is disposed between the resist coating unit (COT)  22  and the edge remover (ER)  23 . Thus, the substrate G coated with the resist solution is carried to the drying unit  80  to be dried and thereafter given end face treatment by the edge remover (ER)  23 .  
         [0080]    As shown in FIG. 6, the drying unit  80  is provided with a shower head  82  for spouting gas such as inactive gas at the upper portion of a boxed-shaped body  81 . Inactive gas and the like are spouted downward from the entire lower face of the shower head  82 .  
         [0081]    An opening  84  for carrying a substrate in and an opening  85  for carrying a substrate out are respectively provided in the front face and the rear face of the box-shaped body  81 , and a portion cut off (not shown) for moving a carrier arm  41  is provided in a side wall thereof. The substrate G is sprayed with inactive gas and the like spouted from the shower head  82  while the substrate G which is brought in from the opening  84  by the carrier arm  41  moving along a guide rail  42  is moved in the box-shaped body  81  and then taken out of the opening  85 .  
         [0082]    By spraying inactive gas and the like on the substrate G while the substrate G is moved, drying of the resist solution coated on the substrate G is progressed and a solvent such as thinner in the resist solution is vaporized to a certain extent.  
         [0083]    As described above, by drying the resist solution on the substrate G by spraying inactive gas and the like in a non-heated state just after coating of the resist solution and before heat treatment in the heating unit (HP), the solvent such as thinner in the resist solution is vaporized to a certain extent, thus promoting drying of the resist without exerting a bad influence on the resist, and effectively preventing the occurrence of transfer on the substrate G.  
         [0084]    Since the solvent such as thinner in the resist solution is vaporized to a certain extent by spraying inactive gas and the like, the excess resist solution can be easily removed when the end face treatment of the substrate G is performed after the drying process.  
         [0085]    Incidentally, the spraying of inactive gas and the like does not necessarily need to be performed while the substrate G is moving, but may be performed while the substrate G is at a standstill. As to the spouting of inactive gas and the like from the shower head  82 , it is possible that inactive gas and the like are spouted from holes in a row instead of holes in the entire lower face.  
         [0086]    Moreover, in place of drying by spraying inactive gas and the like shown in FIG. 6, drying under reduced pressure is available. Specifically, it is possible that a gas exhaust pipe (not shown) having an exhaust pump (not shown) is connected to the box-shaped body  81  and thus gas in a treatment chamber in the box-shaped body  81  is exhausted by the exhaust pump. Also in this case, by pressure being reduced, a solvent such as thinner in a resist solution is vaporized to a certain extent, thus effectively preventing transfer marks of the lifting pins  75  and the like from being left on the substrate G.  
         [0087]    The coating and developing system of an LCD substrate according to another embodiment of the present invention is structured as above. Next, as still another embodiment of the present invention, an example in which the present invention is adopted to a coating film forming system (SOD system) for forming a layer insulating film on a semiconductor wafer will be described.  
         [0088]    [0088]FIG. 7( a ) is a plane view of the upper tier of an SOD system according to still another embodiment of the present invention, FIG. 7( b ) is a plane view of the lower tear of the SOD system, FIG. 8 is a side elevational view of the SOD system shown in FIG. 7, and FIG. 9 is a side elevational view of two units-tiered bodies provided in the SOD system shown in FIG. 7.  
         [0089]    The SOD system schematically includes a treatment section  101 , a side cabinet  102 , and a carrier station (CSB)  103 .  
         [0090]    As shown in FIG. 7( a ) and FIG. 8, the treatment section  101  includes a solvent exchange unit (DSE)  111 , disposed in the upper tier at the front side, for coating a solvent on a substrate W to thereby exchange a solvent on the coating film, a high-viscosity coating unit (SCT)  112  for coating a high-viscosity coating solution on the substrate W, and in addition, as shown in FIG. 7( b ) and FIG. 8, a low-viscosity coating unit (SCT)  113 , disposed in the lower tier at the front side, for coating a high-viscosity coating solution on the substrate W and a chemical chamber  114  storing chemicals and the like.  
         [0091]    As shown in FIGS.  7 ( a ) and  7 ( b ), treating unit groups  116  and  117  in each of which a plurality of treating units are vertically multi-tiered are provided in the central portion of the treatment section  101 , and a carrier mechanism  118  which goes up and down to carry the substrate W is arranged therebetween. As shown in FIG. 9, the left treating unit group  116  is composed of a low-temperature hot plate (LHP)  119 , two DCC treating units (Dielectric Oxygen Density Controlled Cure and Coolling-off)  120  for heating and cooling the substrate in low oxygen-density atmosphere to cure a coating film, and two aging units (DAC)  121  for gelatinizing the coating film, which are tiered in descending order. The right treating unit group  117  is composed of two high-temperature hot plates (OHP)  122 , a low-temperature hot plate (LHP)  123 , two cooling plates (CPL)  124 , a transfer section (TRS)  125 , and a cooling plate (CPL)  126 , which are tiered in descending order. Incidentally, the transfer section (TRS)  125  is structured to function also as a cooling plate.  
         [0092]    The side cabinet  102  includes a bubbler  127  for feeding chemicals and a trap (TRAP)  128  for cleaning exhaust gas in the upper tier thereof, and includes a power supply source  129 , a chemical chamber  130  for storing chemicals such as HMDS and ammonia, and a drain  131  for exhausting drainage in the lower tier thereof.  
         [0093]    Next, a case where a layer insulating film is formed by a sol-gel process in the SOD system structured as above will be described in detail.  
         [0094]    In the sol-gel process, a coating film is usually formed in the sequence of the cooling plates (CPL)  124  and  126 →the low-viscosity coating unit (SCT)  113 →the aging unit (DAC)  121 →the solvent exchange unit (DSE)  111 →the low-temperature hot plates (LHP)  119  and  123 →the high-temperature holt plate (OHP)  122 . Accordingly, when a layer insulating film is formed by the sol-gel process, the treatment section  101  is composed of the low-viscosity coating unit (SCT)  113 , the aging unit (DAC)  121 , the solvent exchange unit (DSE)  111  and the like as the principal section thereof.  
         [0095]    As shown in FIG. 10, the low-viscosity coating unit (SCT)  113  includes a fixed cup  142  with the upper portion thereof being opened and closed with a lid  141 , a rotating shaft  144  which is inserted from the bottom face of the fixed cup  142 , raised and lowered, and rotated by a drive element  143 , a vacuum chuck  145  which is a substrate holding element provided at the upper end of the rotating shaft  144 , and a coating solution nozzle  146  combined with the lid  141  for supplying a coating solution to the central portion of the substrate W. Solvent nozzles  262 , and  263  for supplying a solvent which is a cleaning agent for removing a coating film at the peripheral portion of the substrate W (edge rinse treatment) from a solvent supply source  261  are provided at the bottom face of the fixed cup  142  and at the lid  141  respectively. The main purpose of the solvent nozzle  263  provided at the lid  141  is to discharge a solvent toward the periphery of the front face side of the substrate W. The main purpose of the solvent nozzle  262  provided at the fixed cup  142  is to discharge a solvent toward the periphery of the rear face side of the substrate W to remove a coating solution reaching the rear side of the substrate W. A drain pipe  149  and an exhaust pipe  150  as well as a solvent vapor feed pipe  148  for supplying vapor of a solvent used in a coating solution, for example, ethylene glycol are connected to the fixed cup  142 . A coating solution and a solvent used in this unit is supplied from the chemical chamber  114 . In the chemical chamber  114 , chemicals other than chemicals such as ammonia and HMDS exerting a bad influence on treatment are stored. Incidentally, the high-viscosity coating unit (SCT)  112  is structured almost similarly to the low-viscosity coating unit (SCT)  113 .  
         [0096]    As shown in FIG. 11, the aging unit (DAC)  121  includes a heating plate  151  made of ceramics, for example, with a built-in heater  151   a , a lid  153  which is closely attached to the peripheral portion of the heating plate  151  via a sealing member  152  in such a manner to form a space S composing a treatment chamber above the heating plate  151  and which is detached from the heating plate  151 , a gas feed passage  154  feed ports of which are formed in the surface of the heating plate  151  in such a manner to enclose the substrate W placed on the heating plate  151 , an exhaust passage  155  an inlet port of which is formed at a central portion of the lid  153 , and three raising and lowering pins  156  for raising and lowering the substrate G between the heating plate  151  and a position above the heating plate  151 .  
         [0097]    As described later, in the aging unit (DAC)  121 , ammonia is vaporized by means of the bubbler  127  and a mass flow controller (not shown) in the side cabinet  102  and supplied to the treatment chamber S through the aforementioned gas feed passage  154 , and exhaust gas from the exhaust passage  155  is trapped by the drain tank  131  in the side cabinet  102 .  
         [0098]    As shown in FIG. 12, the solvent exchange unit (DSE)  111  includes a vacuum chuck  161  for rotating the substrate W while horizontally holding it, a rotating cup  162  disposed to surround the substrate W on the chuck  161  and having a drain port  163 , a fixed cup  164 , disposed outside the rotating cup  162 , to which a drain passage  165  and an exhaust passage  166  are connected, and a nozzle  167  for supplying a solvent to the substrate W. The reference numeral  168  in FIG. 12 is a drive element for rotating, raising and lowering a rotating shaft  161   a  of the chuck  161 , and the reference numeral  169  is a drive element for rotating the rotating cup  162 .  
         [0099]    An opening at the upper portion of the aforesaid fixed cup  162  is opened and closed with a lid  170  which can ascend and descend. The nozzle  167  has three replacement nozzles  167   a ,  167   b , and  167   c  for discharging ethanol, HMDS, and heptane, respectively. The replacement nozzles  167   a ,  167   b , and  167   c  are gripped and taken out of nozzle receiving elements  171   a ,  171   b , and  171   c  respectively, and carried to a position above the center of the substrate W. When HMDS is supplied to the replacement nozzle  167   b  of the nozzle  167 , the HMDS is directly supplied from an HMDS tank  130   a  of the side cabinet  102 . Exhaust gas mixed with liquid from the exhaust passage  166  is separated into gas and liquid by a mist trap  128  in the cabinet  102 , and drainage from the drain passage  165  is exhausted to the drain tank  131 .  
         [0100]    The side cabinet  102  is provided at a position adjacent to the treatment section  101 , but isolated from the treatment section  101 , and has the bubbler  127  for feeding chemicals and the mist trap (TRAP)  128  for separating gas-liquid mixture into gas and liquid and exhausting exhaust gas in the upper tier thereof and the power supply source  129 , the chemical chamber  130  for storing chemicals such as HMDS and ammonia, and the drain  131  for exhausting drainage in the lower tier thereof.  
         [0101]    Since the side cabinet  102  is structured as above, when ammonia is supplied to the aging unit (DAC)  121 , the ammonia is filled into the bubbler  127  from an ammonia tank  130   b , and the ammonia is bubbled by the bubbler  127  and vaporized to be supplied to the aging unit (DAC)  121 . When HMDS is supplied to the solvent exchange unit (DSE)  111 , the HMDS is directly supplied from the HMDS tank  130   a.    
         [0102]    Exhaust gas from the aging unit (DAC)  121  is trapped by the drain tank  131  in the side cabinet  102 . In addition, exhaust gas mixed with liquid from the solvent exchange unit (DSE)  111  is separated into gas and liquid by the mist trap  128  in the cabinet  102 , and drainage is exhausted to the drain tank  131 .  
         [0103]    As described above, the aging unit (DAC)  121  and the solvent exchange unit (DSE)  111 , each requiring ammonia and HMDS supplied from the side cabinet  102 , are disposed adjacent to the side cabinet  102 , thus shortening a chemicals feed system.  
         [0104]    After a coating solution is coated on the substrate W, it is preferable that the coating solution is immediately gelatinized (for example, within 10 seconds). Therefore, as shown in FIGS.  7  to  9 , the low-viscosity coating unit (SCT)  113  and the aging unit (DAC)  121  are arranged relatively close to each other. In addition, after the gel treatment, preferably exchange of solvents is immediately performed. Hence, the aging unit (DAC)  121  and the solvent exchange unit (DSE)  111  are arranged relatively close to each other.  
         [0105]    Next, treating operation in the case of forming a layer insulating film by the sol-gel process in the aforesaid SOD system will be described.  
         [0106]    First, the substrate W carried from the carrier station (CSB)  103  to the transfer section (TRS)  125  is carried to the cooling plates (CPL)  124  and  126  to be cooled by means of the carrier mechanism  118 . Thus, temperatures of substrates before coating can be made constant, thereby improving uniformity of film thickness and film quality.  
         [0107]    Subsequently, the substrate W is carried to the low-viscosity coating unit (SCT)  113  and delivered to the chuck  145  as shown in FIG. 10, and the rotating cup  142  is tightly closed by the lid  141 . The coating solution to be used here is that colloids or particles of TEOS are dispersed in an organic solvent and water and a small amount of hydrochloric acid are contained therein. While gas is exhausted from the exhaust pipe  150 , vapor of the organic solvent is supplied into the rotating cup  142  from the solvent vapor feed pipe  148 , and after the rotating cup  142  is filled with vapor of the organic solvent, exhaust is stopped, and the coating solution is dropped on the central portion of the substrate W from the nozzle  146 . Subsequently, the substrate W is rotated by the chuck  145 , and the coating solution spreads over the surface of the substrate W, thereby forming a coating film. In addition, a solvent is supplied to the peripheral portion of the substrate W from the nozzles  262  and  263  to remove the peripheral portion of the coating film on the substrate W. Due to the aforesaid removal of the coating film on the peripheral portion of the substrate W, the carrier mechanism  118  and the coating solution do not touch with each other when the coated substrate W is carried. Consequently, it is prevented that the carrier mechanism  118  is smudged with the coating solution and that the adherent coating solution is dried to become particles, which results in contamination of the inside of the unit. The reason why the coating treatment is performed with the rotating cup  142  filled with the vapor of the organic solvent is that vaporization of the solvent in the coating solution is prevented.  
         [0108]    The substrate W on which the coating film is thus formed is carried to the aging unit (DAC)  121 . As shown in FIG. 11, in the aging unit (DAC)  121 , the lid  153  is raised, and the substrate W is delivered to the raising and lowering pins  156  and brought close to the heating plate  151 . After the lid  153  is shut down, while gas is exhausted from the exhaust passage  155 , ammonia is supplied into the treatment chamber S from the bubbler  127  in the cabinet  102  through the gas feed passage  154 . At this time, the substrate W is heated at a temperature of 100° C., for example. Consequently, colloids contained in the coating film on the substrate W are gelatinized and linked in the form of a mesh of a net.  
         [0109]    Thereafter, the substrate W is carried to the solvent exchange unit (DSE)  111 . As shown in FIG. 12, in the solvent exchange unit (DSE)  111 , the substrate W is delivered to the vacuum chuck  161 , a moisture-soluble chemical, for example, ethanol is dropped on the central portion of the substrate W from the replacement nozzle  167   a  of the nozzle  167 , and the substrate W and the rotating cup  162  are rotated to spread the ethanol over the entire surface of the substrate W. Thus, the ethanol is dissolved into moisture in the coating film, and as a result, the moisture is exchanged for the ethanol.  
         [0110]    Subsequently, the lid  170  is taken off, and HMDS is dropped on the central portion of the substrate W in the same way as above, whereby hydroxide salt in the coating film is removed. Moreover, heptane is dropped on the substrate W, and a solvent in the coating film is exchanged for the heptane. The reason for using heptane is that the use of a solvent with small surface tension allows force applied to a porous structural body, that is, a net-shaped structural body of TEOS to reduce, thus preventing the structural body from being broken.  
         [0111]    As described above, as a preliminary process before heat treatment, treatment is performed for the substrate w, on which a coating film is already formed, in the aging unit (DAC)  121  and the solvent exchange unit (DSE)  111 . As a result, the coating film on the substrate W can be gelatinized and the solvent in the coating film can be exchanged without the organic solvent in the coating film necessary for forming a layer insulating film being dried.  
         [0112]    Although ammonia is used in the above aging unit (DAC)  121  and HMDS and heptane are used in the solvent exchange unit (DSE)  111 , the present invention is not limited to them.  
         [0113]    Thereafter, the substrate W is heat-treated at a relatively lower temperature in the low-temperature hot plates (LHP)  119  and  123  (a first heating process). Heating conditions under this situation are, for example, a heating temperature (a first predetermined temperature) of 60° C. to 90° C. and a heating time of about 60 seconds.  
         [0114]    In a non-heated process after the first heating process, after being carried out of the low-temperature hot plate (LHP), the substrate W is left in a non-heated state and naturally cooled by natural heat release or positively cooled by the cooling plates (CPL)  124  and  126 .  
         [0115]    In a second heating process after the non-heated process, the substrate W is heat-treated at a relatively higher temperature in the high-temperature hot plate (OHP)  122  to thereby finish a layer insulating film. In this situation, the heating temperature (a second predetermined temperature) is 150° C. to 340° C. and the heating time is about 60 seconds. The substrate W on which the layer insulating film is thus formed is returned to the carrier station (CSB)  103  via the transfer section (TCP)  125 .  
         [0116]    As described above, the substrate W coated with the coating solution is heated at 60° C. to 90° C. (the first predetermined temperature). After the above heating, the substrate W naturally releases heat in a non-heated state or cooled, and after natural cooling by the natural heat release or positive cooling, heated at 150° C. to 340° C. (the second predetermined temperature). By raising stepwise temperature in heat treatment as described above, the organic solvent in the coating solution is more gradually released, as compared with abrupt heating. According to the results of experiments, drying of the coating solution can be promoted without exerting a bad influence on the coating solution, and the occurrence of transfer on the substrate W can be effectively prevented.  
         [0117]    Further, if required, it is possible that after the above second heating process, the substrate W is left again in a non-heated state to be naturally cooled by natural heat release, or the substrate W is positively cooled by the cooling plates (CPL)  124  and  126 , and then a coating film formed on the surface of the substrate W is cured in the DCC treating unit which is described later. In this situation, the heating temperature (a third predetermined temperature) is 400° C. to 450° C. and the heating time is about 30 seconds. It is possible to use a heating furnace (not shown) which can heat a plurality of substrates W at the same time instead of the DCC treating unit.  
         [0118]    Incidentally, the first, the second, and the third predetermined temperatures, heating times and the like are not limited to the above values. It is preferable, however, that the first heating temperature (the first predetermined temperature) is lower than the second heating temperature (the second predetermined temperature), and that the second heating temperature (the second predetermined temperature) is lower than the third heating temperature (the third predetermined temperature).  
         [0119]    Further, in this embodiment, heating processes and non-heated processes may be repeated a plurality of times, for example, a heating process→a non-heated process→a heating process→a non-heated process . . . . Also in this case, the substrate W is repeatedly heated and naturally cooled by natural heat release or positively cooled, whereby the organic solvent in the coating solution is gradually released. Thus, drying of the coating solution can be promoted without exerting a bad influence on the coating solution, and the occurrence of transfer on the substrate can be effectively prevented.  
         [0120]    In the above embodiment, before heat treatment, the coating film on the substrate W is gelatinized and the solvent in the coating film is exchanged. But, depending on the heating temperature in the first heating process, the coating film on the substrate W can be gelatinized and the solvent in the coating film can be exchanged between the first heating process and the second heating process.  
         [0121]    Next, a case where a layer insulating film is formed by a silking method, a speed filming method, or a foxing method in the aforesaid SOD system will be described in detail.  
         [0122]    In the silking method, the speed filming method, or the foxing method, a coating film is formed in the sequence of the cooling plates (CPL)  124  and  126 →the first coating unit (SCT)  113  (coating of an adhesion promoter) the low-temperature hot plates (LHP)  119  and  123 →the cooling plates (CPL)  124  and  126 →the second coating unit (SCT)  112  (coating of the chemicals)→the low-temperature hot plates (LHP)  119  and  123 →the high-temperature hot plate (OHP)  122 →the DCC treating unit (DCC)  120 .  
         [0123]    Incidentally, in the foxing method, a coating film may be formed in the sequence of the cooling plates (CPL)  124  and  126 →the coating unit (SCT)  112 →the low-temperature hot plates (LHP)  119  and  123 →the high-temperature hot plate (OHP)  122 →the DCC treating unit (DCC)  120  without the coating of an adhesion promoter in the first coating unit (SCT)  113 .  
         [0124]    In the above units, the DCC treating unit  120  includes a heating chamber  181  and a cooling chamber  182  provided adjacent thereto as shown in FIGS. 13 and 14. Provided in the heating chamber  181  is a hot plate  183  capable of setting temperature at 200° C. to 470° C. The DCC treating unit  120  further includes a first gate shutter  184  which is opened and closed when the substrate W is sent and received to/from the main carrier mechanism  118  (FIG. 7 and FIG. 9), a second gate shutter  185  for opening and closing a space between the heating chamber  181  and the cooling chamber  182 , and a ring shutter  186  raised and lowered together with the second gate shutter  185  while surrounding the substrate w around the hot plate  183 . In the hot plate  183 , three lifting pins  187  for mounting, and raising and lowering the substrate W are provided to be free to go up and down. Incidentally, a shielding screen may be provided between the hot plate  183  and the ring shutter  186 .  
         [0125]    Below the heating chamber  181 , a raising and lowering mechanism  188  for raising and lowering the above three lifting pins  187 , a raising and lowering mechanism  189  for raising and lowering the ring shutter  186  together with the second gate shutter  185 , and a raising and lowering mechanism  190  for raising and lowering, and opening and closing the first gate shutter  184  are provided.  
         [0126]    Further, inactive gas such as N 2  is fed into the heating chamber  181  from a supply source not shown, and the inside of the heating chamber  181  is exhausted through an exhaust pipe  191 .  
         [0127]    Therefore, the inside of the heating chamber  181  is maintained in low oxygen-density atmosphere (for example, 50 ppm or less) by exhausting while supplying inactive gas.  
         [0128]    The heating chamber  181  and the cooling chamber  182  communicate with each other through a communicating port  192 , and a cooling plate  193  for placing and cooling the substrate W is structured to be horizontally movable along a guide rail  194  by means of a moving mechanism  195 . Thus, the cooling plate  193  can enter the heating chamber  181  through the communicating port  192 , receives the substrate W which is already heated by the hot plate  183  in the heating chamber  181  from the lifting pins  187 , then carries the substrate W into the cooling chamber  182 , and returns the substrate W on the lifting pins  187  after the substrate W is cooled.  
         [0129]    Incidentally, the set temperature of the cooling plate  193  is 15° C. to 25° C., for example, and the applicable temperature range of the substrate W to be cooled is 200° C. to 470° C., for example.  
         [0130]    The cooling chamber  182  is structured to be filled with inactive gas such as N 2  through a feed pipe  195  and exhausted to the outside through an exhaust pipe  197 . Thus, the inside of the cooling chamber  182  is maintained in low oxygen-density atmosphere (for example, 50 ppm or less) similarly to the heating chamber  181 .  
         [0131]    Next, treating operation for forming a layer insulating film by the silking method, the speed filming method, and the foxing method will be described.  
         [0132]    The substrate W carried from the carrier station (CSB)  103  to the transfer section (TRS)  125  is carried to the cooling plates (CPL)  124  and  126  to be cooled. As is the case with the sol-gel process, the temperature of the substrate W can be made constant by cooling before coating, thereby improving uniformity of film thickness and film quality.  
         [0133]    Subsequently, the substrate W is carried to the low-viscosity coating unit (SCT)  113  and coated with an adhesion promoter as a first coating solution by means of the aforesaid spin coating. The adhesiveness of a film is promoted by coating the adhesion promoter prior to the coating solution. Thereafter, the substrate W is appropriately heat-treated by the low-temperature hot plates (LHP)  119  and  123  and carried to the cooling plates (CPL)  124 ,  126 , where the temperature of the substrate W is controlled. Then, the substrate W is carried to the high-viscosity coating unit (SCT)  112  and coated with the coating solution for a layer insulating film as a second coating solution by means of the aforesaid spin coating.  
         [0134]    Thereafter, the substrate W is heat-treated at a relatively lower temperature in the low-temperature hot plates (LHP)  119  and  123  (a first heating process). In this situation, the heating temperature (a first predetermined temperature) is 60° C. to 90° C. and the heating time is about 30 seconds. In a non-heated process after the first heating process, after being carried out of the low-temperature hot plate (LHP), the substrate W is left in a non-heated state and naturally cooled by natural heat release or positively cooled by the cooling plates (CPL)  124  and  126 . In a second heating process after the non-heated process, the substrate W is heat-treated at a relatively higher temperature in the high-temperature hot plate (OHP)  122  (the second heating process). In this situation, the heating temperature (a second predetermined temperature) is 280° C. to 340° C. and the heating time is longer than the heating time in the first heating process, for example, about 90 seconds. Moreover, after the second heating process, a non-heated process similar to the above one is performed.  
         [0135]    As described above, heating processes and non-heated processes are repeated for the substrate W. With the repetition of processes, the heating temperature is raised, thus gradually releasing the organic solvent in the coating solution, promoting drying of the coating solution without exerting a bad influence on the coating solution, and effectively preventing the occurrence of transfer on the substrate W as is the case for the aforesaid sol-gel process.  
         [0136]    Further, in the silking method, the speed filming method, and the foxing method, curing treatment (a third heating process) is performed for the substrate W in the DCC treating unit  120 . Specifically, the first gate shutter  184  is opened, and the substrate W is carried onto the three lifting pins  187  in the heating chamber  181  from the main carrier mechanism  118  (FIGS. 7 and 9). The first gate shutter  184  is closed, the ring shutter  186  and the second gate shutter  185  are raised, and the substrate W is surrounded by the ring shutter  186 . At this time, the filling of inactive gas such as N 2  into the heating chamber  181  is started, whereby the inside of the heating chamber  181  is maintained in low oxygen-density atmosphere (for example, 50 ppm or less).  
         [0137]    Thereafter, the lifting pins  187  are lowered, whereby the substrate W is placed close to the hot plate  183  and heat-treated in the low oxygen-density atmosphere (for example, 50 ppm or less). The heating temperature is, for example, 200° C. to 470° C. (a third predetermined temperature). In addition, in-plane uniformity is favorable because of heating by the hot plate  183  instead of heating by a heating furnace.  
         [0138]    After heat treatment is completed, the ring shutter  186  and the second gate shutter  185  are lowered, and the lifting pins  187  are raised. At this time, feeding of inactive gas such as N 2  into the heating chamber  181  is stopped, and feeding of inactive gas such as N 2  into the cooling unit  182  is started, thereby maintaining the inside of the cooling chamber  182  in low oxygen-density atmosphere (for example, 50 ppm or less). Thereafter, the cooling plate  193  enters the heating chamber  181  to receive the substrate W from the lifting pins  187 , and the lifting pins  187  are lowered.  
         [0139]    Then, the cooling plate  193  is returned into the cooling treatment  182 , the second gate shutter  185  is raised, and the substrate W is cooled in low oxygen-density atmosphere (for example, 50 ppm or less). The cooling temperature at this time is, for example, 200° C. to 400° C., and the substrate W is cooled in low oxygen-density atmosphere, thereby effectively preventing oxidation of the film. After completing the cooling, feeding of inactive gas such as N 2  into the cooling chamber  182  is stopped.  
         [0140]    Thereafter, the second gate shutter  185  is lowered and the cooling plate  193  enters the heating chamber  181 . Subsequently, the lifting pins  187  are raised, and the substrate W is returned onto the lifting pins  187  from the cooling plate  193 . After carrying the substrate W out, the cooling plate  193  is returned into the cooling chamber  182  and the first gate shutter  184  is opened. Then, the substrate W is returned to the main carrier mechanism  118  (FIGS. 7 and 9). Thus, heating and cooling for curing the coating film are completed. Thereafter, the substrate W which finishes the layer insulating film is returned to the carrier station (CBS)  103  via the transfer section (TRS)  125  by means of the carrier mechanism  118 .  
         [0141]    Incidentally, the first, the second, and the third predetermined temperatures, heating times and the like are not limited to the above values. It is preferable, however, that the first heating temperature (the first predetermined temperature) is lower than the second heating temperature (the second predetermined temperature) and that the second heating temperature (the second predetermined temperature) is lower than the third heating temperature (the third predetermined temperature). The treatment is performed with the heat treatment temperature being raised stepwise up to the final heat treatment temperature. In addition, instead of the DCC treating unit, a heating furnace (not shown) which can heat a plurality of substrates W at the same time may be used.  
         [0142]    As described above, the aforesaid SOD system is provided with treating units accordant with various coating methods, that is, the sol-gel process, the silking method, the speed filming method, and the foxing method. Therefore, a coating film according to each of the various coating methods can be formed in one system.  
         [0143]    It should be mentioned that the present invention is not limited to the above embodiments, and various variations may be made.  
         [0144]    As described above, according to the present invention, the substrate coated with the coating solution is heated at the first predetermined temperature, and after the above heating, through the non-heated process, the substrate is heated at the second predetermined temperature, or the process of heating the substrate coated with the coating solution and the process of putting the substrate in the non-heated state are repeated, thus gradually releasing the solvent in the coating solution, promoting drying of the coating solution without exerting a bad influence on the coating film, and effectively preventing the occurrence of transfer on the substrate.  
         [0145]    Further, the heating temperature in the first heating process is made lower than that in the second heating process, thus holding down abrupt vaporization of the solvent in the coating solution to provide a more appropriate dried state and more effectively preventing the occurrence of transfer. The above difference in temperature can be realized by providing a low-temperature heating unit and a high-temperature heating unit both of which are different in set temperature, and by setting a space between the substrate and a heating plate in the first heating process larger than that in the second heating process.