Abstract:
A substrate processing apparatus comprising a substrate mounting table, a cup having an upper opening and surrounding the substrate mounting table, a lid for opening/closing the upper opening of the cup, a support arm for supporting the lid, a first lifting mechanism having a first piston for supporting the support arm directly or indirectly and a first cylinder for guiding the first piston in an up-and-down motion, a second lifting mechanism having a second piston for supporting the support arm directly or indirectly and a second cylinder for guiding the second piston in up-and -down motion, a driving circuit for supplying the pressurized fluid to the first and second cylinders, independently and exhausting the pressurized fluid from the first and second cylinders, independently, and a control mechanism for controlling operations of the driving circuit.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a substrate processing apparatus comprising a cup and a lid which define a processing space for processing a large substrate such as a glass substrate for a liquid crystal display (LCD). 
     In an LCD manufacturing process, similarly in a manufacturing process for a semiconductor device, a photolithographic technology is employed. In the LCD photolithographic process, a resist coating film is formed on a glass substrate, and then subjected to pattern exposure and development. Thereafter, a semiconductor layer, an insulating layer and an electrode layer formed on the substrate are selectively etched to form an ITO (Indium Tin Oxide) thin film and an electrode pattern. 
     A resist solution is coated on the LCD substrate by use of a so-called spin-coating method, for example, disclosed in U.S. Pat. No. 5,688,322. Operation using coating apparatus of this type is performed as follows: First, a lid is opened and a substrate is loaded into a cup. While the substrate is adsorbed and held by a spin chuck, a solvent and a resist solution are poured dropwise onto the surface of the substrate. After the lid is closed, the substrate is rotated by the spin chuck. Then, the lid is opened and the substrate is unloaded from the cup. Finally the lid is closed. 
     The lid is supported at one side by a support arm which is movable up and down by an air cylinder mechanism. In a conventionally employed apparatus, the maximum stroke amount required for lifting the lid from the cup, is equal to that of the cylinder. Therefore, the distance between the lid and the cup is short, with the result that a sufficient space cannot be ensured for cleaning the inside of the cup. To clean the inside of the cup, the lid and the support arm must be removed from the apparatus main body every time. However, it is inconvenient to remove them from the main apparatus. 
     In addition, because the lid and the support arm are large and heavy, it is difficult to handle them. When they are removed from and attached to the apparatus main body, they may possibly hit the cup and its accessories and destroy them. Furthermore, an excessive load is imposed on the air cylinder mechanism when the lid is lifted, so that machine trouble frequently takes place. Therefore the conventional apparatus is short in lift. On the other hand, when the lid is moved down, it takes too much time to exhaust the inner air from the cylinder, with the result that the throughput is low. 
     BRIEF SUMMARY OF THE INVENTION 
     An object of the present invention is to provide a substrate processing apparatus capable of opening and closing a lid during the substrate processing time and performing operation simple and securely without taking the apparatus apart during the maintenance operation time. 
     According to the present invention, there is provided a substrate processing apparatus comprising 
     a substrate mounting table; 
     a cup having an upper opening and surrounding the substrate mounting table; 
     a lid for opening/closing the upper opening of the cup; 
     a support arm for supporting the lid; 
     a first lifting mechanism having a first piston for supporting the support arm directly or indirectly and a first cylinder for guiding the first piston in an up-and-down motion; 
     a second lifting mechanism having a second piston for supporting the support arm directly or indirectly and a second cylinder for guiding the second piston in up-and -down motion; 
     a driving circuit for supplying the pressurized fluid to the first and second cylinders, independently and exhausting the pressurized fluid from the first and second cylinders, independently; and 
     a control mechanism for controlling operations of the driving circuit. 
     According to the present invention, there is provided a substrate processing apparatus comprising 
     a substrate mounting table; 
     a cup having an upper opening and surrounding the substrate mounting table; 
     a lid for opening/closing the upper opening of the cup; 
     a support arm for supporting the lid; 
     a cylinder mechanism having a piston for transmitting a driving force for moving the support arm up and down, to the support arm; 
     an upper pulley set at a position higher than an upper dead point of the piston of the cylinder mechanism 
     a lower pulley set at a position lower than the upper pulley; 
     an endless belt stretching between the upper and lower pulleys to one side of which said support arm is fastened; and 
     a weight fastened to the other side of the endless belt so as to keep a balance of the support arm and the lid. 
     Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter. 
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
     The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate presently preferred embodiments of the invention, and together with the general description given above and the detailed description of the preferred embodiments given below, serve to explain the principles of the invention. 
     FIG. 1 is a schematic plan layout showing an LCD substrate processing system; 
     FIG. 2 is a schematic front outlook showing an LCD substrate processing system; 
     FIG. 3 is a perspective view showing a coating section of the coating/peripheral coating film removing unit; 
     FIG. 4 is a schematic plan view of the coating/peripheral coating film removing unit; 
     FIG. 5 is a plan view showing a state of the apparatus from which a lid has been removed; 
     FIG. 6 is a perspective cross-sectional view showing a gist portion of the coating section; 
     FIG. 7 is a perspective cross-sectional view of a lid lifting cylinder mechanism of the substrate processing apparatus according to an embodiment of the present invention; 
     FIG. 8 is an exploded view showing a lid and a cup; 
     FIG. 9 is a magnified cross sectional view of a lid lifting cylinder mechanism (with the lid closed) during coating processing time; 
     FIG. 10 is a magnified cross sectional view of the lid lifting cylinder mechanism (with the lid open) during coating processing time; 
     FIG. 11 is a magnified cross sectional view of the lid lifting cylinder mechanism (with the lid lifted up to the uppermost limit) during the maintenance time; 
     FIG. 12 is a block circuit diagram of the substrate processing apparatus according to an embodiment of the present invention; 
     FIG. 13 is a longitudinal sectional view of a speed controller (SC); 
     FIG. 14 is a longitudinal sectional view of quick exhausting valve (QEV); 
     FIG. 15 is a circuit diagram of a pilot check valve (PCV); 
     FIG. 16 is a flow chart showing a substrate processing method; 
     FIG. 17 is a block circuit diagram showing how to open the lid in a substrate processing apparatus according to an embodiment of the present invention; 
     FIG. 18 is a block circuit diagram showing how to close the lid in a substrate processing apparatus according to an embodiment of the present invention; 
     FIG. 19 is a block circuit diagram showing how to allow the lid to step aside during the maintenance time in the substrate processing apparatus according to an embodiment of the present invention; 
     FIG. 20 is a block circuit diagram showing how to return the lid during the maintenance time in the substrate processing apparatus according to an embodiment of the present invention; 
     FIG. 21 is a plan view of a substrate processing apparatus according to another embodiment of the present invention; 
     FIG. 22 is a partial plan view of a substrate processing apparatus according to another embodiment of the present invention; 
     FIG. 23 is a partial plan view of a substrate processing apparatus according to another embodiment of the present invention; and 
     FIG. 24 is a partial plan view of a substrate processing apparatus according to another embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Now, various preferred embodiments of the present invention will be described with reference to the accompanying drawings. 
     As shown in FIGS. 1 and 2, a coating/developing processing system  1  has a loader/unloader section  2 , a first processing section  3 , a second processing section  4 , a third processing section  5 , and an interface section  6 . The processing system  1  has various processing mechanisms for coating a photoresist solution onto an LCD substrate G and developing the resist coating film. The processing system  1  is connected to a light-exposure apparatus  7  with an interface section  6  interposed between them. 
     The loader/unloader section  2  has a cassette table  10  and a transportation section  11 , each extending in an X-axis direction. On the cassette table  10 , at most four cassettes C 1 , C 2  are mounted side by side. Unprocessed LCD substrates G are stored in two cassettes C 1  and processed LCD substrates G are stored in the other two cassettes C 2 . For example, 25 LCD substrates G at maximum can be stored in each of the cassettes C 1  and C 2 . 
     In the transportation section  11 , a first sub arm mechanism  13  is provided. The first sub-arm mechanism  13  has a holder for loading/unloading the substrate G into the cassettes C 1  and C 2 , a back and forth moving mechanism for moving the holder back and forth, an X-axis moving mechanism for moving the holder in the X-axis direction, a Z-axis moving mechanism for moving the holder in the Z-axis direction, and a θ rotation mechanism for rotating the holder about the Z-axis in a swinging manner. 
     The first processing section  3  has a central transportation passage  15 A extending in the Y-axis direction, a first main arm mechanism  14 A movably provided along the transportation passage  15 A, and a plurality of units  16 ,  17 ,  18 ,  19 . Two wet-washing units  16  are arranged along one side of the transportation passage  15 A. The wet-wash unit  16  has a brush scrubber SCR for scrub-washing the surface of the substrate G with a rotating brush while poring a washing solution to the substrate G. Along the other side of the transportation passage  15 A, a heating unit  17 , a dry-washing unit  18  and a cooling unit  19  are arranged. The heating unit  17  has a two-stage (upper and lower stage) hot plate HP 1  for heating the substrate G. The dry washing unit  18  has an ultraviolet washing apparatus UV for washing the surface of the substrate G by irradiating ultraviolet rays to the substrate G. The cooling unit  19  has a cooling plate COL 1  for cooling the substrate G. A first main arm mechanism  14 A has a holder  14   a  for holding the substrate G, a back and forth moving mechanism for moving the holder  14   a  back and forth, an Y-axis moving mechanism for moving the holder  14   a  back and forth, a Z-axis moving mechanism for moving the holder  14   a  back and forth, and a θ-rotation mechanism for rotating the holder  14   a  about the Z-axis in a swinging mechanism. 
     The second processing section  4  has a central transportation passage  15 B extending in the Y-axis direction, a second main arm mechanism  14 B movably provided along the transportation passage  15 B, and a plurality of processing units  21 ,  24 ,  25 ,  26 . A resist coating/peripheral resist removing unit  21  is arranged along one of the sides of the transportation passage  15 B. The unit  21  has a coating apparatus CT for coating the resist solution onto the substrate G while spin-rotating the substrate G and a peripheral resist removing apparatus ER for removing a resist coating film from the peripheral portion of the substrate G. An adhesion/cooling unit  24 , a heating/cooling unit  25 , and a heating/heating unit  26  are arranged along the other side of the transportation passage  15 B. The adhesion/cooling unit  24  has an adhesion device AD for imparting hydrophobic properties onto the surface of the substrate G with HMDS vapor and a cooling plate COL  3  for cooling the substrate G. The heating/cooling unit  25  has a hot plate HP 2  for heating the substrate G and a cooling plate COL  3  for cooling the substrate G. The heating/heating unit  26  has a two-stage (upper and lower) hot plate HP 2  for heating the substrate G. 
     The third processing section  5  has a central transporting passage  15 C extending in the Y-axis direction, a third main arm mechanism  14 C movably provided along the transportation passage  15 C, and a plurality of processing units  28 ,  29 ,  30 ,  31 ,  32 ,  33 ,  34 . Three development units  28 ,  29 ,  30  are arranged along one side of the transportation passage  15 C. Each of the units  28 ,  29 ,  30  has a development apparatus DEV for developing a resist coating film by pouring a development solution onto the substrate G. Along the other side of the transportation passage  15 C, a titler  31 , a heating/heating unit  32 , heating/cooling units  33 ,  34  are arranged. The second and third main arm mechanisms  14 B,  14 C are substantially the same as the first main arm mechanism  14 A. A cooling unit  20  is provided between the first process section  3  and the second process section  4 . A cooling unit  27  is provided between the second process section  4  and the third process section  5 . The cooling units  20 ,  27  are used as a temporal stand-by position for the unprocessed substrate G. 
     The interface section  6  is provided between the third process section and the light exposure apparatus  7 . The interface section  6  has a transportation/stand-by portion  36  and a transfer section  37 . The transportation/stand-by portion  36  is equipped with the sub-arm mechanism  35  and two buffer cassettes BC. The second sub arm mechanism  35  is substantially the same as the first sub arm mechanism  13 . In each of the buffer cassette BC, the unprocessed substrates G are stored. The buffer cassette BC is used as a temporal stand-by position for the substrate G. The transfer section  37  has a transfer table (not shown). The substrate G is transferred between a transfer mechanism (not shown) of the light-exposure apparatus  7  and the second sub-arm mechanism  35  via the transfer table. 
     Now, referring to FIGS.  3 - 6 , the resist coating/peripheral coating film removing unit  21  will be explained. 
     As shown in FIGS. 4, the unit  21  has a resist coating apparatus  21 A (CT) and a peripheral coating film removing apparatus  21 B (ER). Two open/shut ports (not shown) are formed on a front wall of the unit  21 . The substrate G is loaded into the resist coating apparatus  21 A through one of the open/shut ports and unloaded from the peripheral coating film removing apparatus  21 B through the other open/shut port. A transportation mechanism  262  is formed between the resist coating apparatus  21 A and the peripheral coating film removing section  21 B. The substrate G is transported by the transportation mechanism  262  from the resist coating apparatus  21 A to the peripheral coating film removing apparatus  21 B. 
     As shown in FIGS. 3 and 6, the resist coating apparatus  21 A has a spin chuck  43 , a rotation cup C P, a drain cup  41 , a lid  42 , and a coating solution supply mechanism  150 . The spin chuck  43  has a rotating mechanism with a stepping motor  45 , a vacuum adsorption mechanism  48 A, and a liftable cylinder mechanism  48 B. A belt  46  is stretched between a driving pulley of the motor  45  and a follower pulley of the spin chuck shaft  47 . One end of the passage of the vacuum adsorption mechanism  48 A is opened at an upper surface of the spin chuck  43 . The other end of the passage communicates with suction side of a vacuum evacuation pump (not shown) via a labyrinth sealing portion. The rod of the liftable cylinder mechanism  48 B is connected to the spin chuck shaft  47 . 
     A rotation cap CP is provided so as to surround the spin chuck  43 . The rotation cap CP and the spin chuck  43  are synchronously rotated by a common motor  45 . The upper portion of the rotation cup CP is opened. The lid  42  is provided so as to cover the opening. The rotation cup CP has a size of 830 mm×650 mm, which is an enough volume to store the substrate G. A plurality of discharge holes are formed in the lower peripheral portion of the rotation cup CP. Liquid drops and mist are discharged from the rotation cup CP to a drain cup  41  through the discharge holes. 
     The drain cup  41  is formed so as to surround the rotation cup CP. A plurality of discharge ports  41 d are formed at the bottom of the drain cup  41 . Discharge solution is discharged from the drain cup  41  to a recover/regeneration apparatus (not shown) through the discharge ports  41 . Four exhaust ports  41   f  are formed at a side periphery portion of the drain cup  41 . Mist is discharged from the drain cup  41  to the recover/regeneration apparatus (not shown) through the exhaust ports  41   f . Note that each of the exhaust ports  41   f  communicates to a suction port of the vacuum evacuation pump (not shown) through the exhaust pipe  41   e.    
     A coating solution supply mechanism  150  has a horizontal arm  155 , a swinging mechanism  156 , a nozzle portion  157 , and a stand-by portion  158 . The proximal end of the horizontal arm  155  is rotatably supported by the vertically moving shaft of the swinging mechanism  156 . The nozzle portion  157  is fixed at a free end of the horizontal arm  155 . The nozzle portion  157  reciprocally moves by means of the swinging mechanism  156  between the stand-by portion  158  (home position) and a portion (operation position) above a rotation center of the spin chuck  43 . The nozzle portion  157  has two nozzles (not shown). One of the nozzles is used for supplying a resist solution. The other nozzle is used for supplying a solvent (thinner). 
     As shown in FIG. 4, the peripheral coating film removing section  21 B has a table  230  for adsorbing and holding the substrate G, four guide rails  232  formed around the table  230 , solvent discharge nozzles  234 , movably provided along the corresponding guide rails  232 , and scan-moving mechanisms  236  for moving the corresponding nozzles  234 . Furthermore, a plurality of approach sensors  238  are provided appropriately so as to prevent collision of the nozzles  234 . 
     As shown in FIG. 8, the rotation cup CP is covered with the lid  42 . The lid  42  is made of aluminium alloy and has a diameter of about 1100 mm. The total weight of the lid  42  and the support arm  61  is about 50 kg. A shaft  42   b  is threaded through the center of the lid  42 . A handle  42 a is provided at an upper end of the shaft  42   b . A rectification plate (not shown) described later is provided at a lower end of the shaft  42   b . The handle  42   a  is connected to the support arm  61  of a lifting mechanism  60  described later. 
     The peripheral portion of the cup  42  is slightly higher than the other portion thereof, thereby forming a peripheral stepped portion. A plurality of recesses  42   c  are formed at the lower surface of the peripheral stepped portion. On the other hand, a plurality of projections  41   c  are formed on the upper surface of the peripheral portion of the rotation cup CP. When the lid  42  is placed on the rotation cup CP, the recesses  42  are engaged with the corresponding projections  41   c , thereby fixing the lid  42  to the rotation cup CP. As a result, the lid  42  is tightly integrated to the rotation cup CP to form a processing space inside the cup. 
     The rectification plate (not shown) is attached to the lower portion of the lid  42 . Air is introduced into the processing space through air supply holes  42   d , spreads radically along the rectification plate, and flows out from the processing space to the drain cup  41  through the exhaust ports. The air flow plays a role in discharging liquid drops and mist of the resist solution from the processing space swiftly and smoothly. Since the air supply holes  42   d  play a role in preventing the inner pressure of the rotation cup CP from being reduced to an excessively negative value. The lid  42  can be therefore removed off easily from the rotation cup CP. 
     As shown in FIG. 6, the spin chuck  43  is moved down by the liftable cylinder mechanism  48 B to a position lower than the upper surface of the cup CP  41  during the coating time. On the other hand, when the substrate is transferred, the spin chuck  43  is moved up by the liftable cylinder mechanism  48 B to a position higher than the upper surface of the cup CP  41 . 
     Next, referring to FIGS.  3 - 15  and FIGS.  18 - 20 , the liftable mechanism  60  for ascending the lid  42  will be explained. 
     As shown in FIG. 4, the liftable mechanism  60  is arranged within the coating section  21 A at the longest distance from the peripheral coating film removing section (edge remover)  21 B. The liftable mechanism  60  has a support arm  61  and a guide post  62 . The support arm  61  extends horizontally from the guide post  62 . The lid  42  is supported by the support arm  61  at the one distal end of the support arm  61 . The support arm  61  has a pair of arm members  61   a  sandwiching the lid  42  and two ribs  61   b  for reinforcing the pair of arm members  61   a  by mutually connecting them. 
     As shown in FIG. 3, a pair of grooves  62   a  are formed vertically in parallel in the front surface of the guide post  62 . The arm members  61   a  are moved while being guided through the corresponding grooves  62   a . As shown in FIGS. 4 and 6, linear guides  63  are vertically formed on the corresponding inner walls of the guide post  62 . To each of the linear guides  63 , a corresponding proximal end portion of the arm member  61   a  is fixed via a rod-form projection  61   c.    
     As shown in FIG. 6, a cylinder mechanism  64  is provided at a lower portion of the support arm  61 . The cylinder mechanism  64  is passed through a bottom plate  44 . An upper half portion of the cylinder mechanism  64  is located within the guide post  62  and a lower half portion thereof is present outside the guide post  62 . 
     As shown in FIGS. 7,  18 - 20 , three shock absorbers  190 A,  190 B,  190 C are attached to the guide post  62  for the sake of security and damage protection. The first shock absorber  190 A is attached to the upper portion of the guide post  62  and plays a role in absorbing and mitigating shock due to the collision of the support arm  61  when it is lifted rapidly. The second shock absorber  190 B is attached to the lower portion of the guide post  62  and plays a role in absorbing and mitigating shock due to the collision of the lid  42  when it falls rapidly. The third shock absorber  190 C is attached to the tip of the horizontal arm  192  supported by the support post  193 . To the horizontal arm  192 , a slit guide  192   a  is formed. The arm  192  is fastened to the support post  193  by a fixing tool  194  through the slit guide  192   a . When the fixing tool  194  is loosened, the arm  192  is ready to slide, with the result that the third shock absorber  190 C can be loaded into and unloaded from the internal portion of the guide post  62 . The third shock absorber  190 C is loaded into the internal portion of the guide post  62  during the substrate processing time and unloaded from the internal portion of the guide post  62  during the maintenance operation. 
     Next, referring to FIGS.  7  and  9 - 11 , the cylinder mechanism of the cup lifter  60  will be explained more specifically. 
     The rod  65  can project and withdraw from the upper portion  65   a  of the cylinder mechanism  64 . The upper portion  65   a  of the rod  65  is connected to a lower portion of the support arm  61 . On the other hand, the lower portion of the rod  65  is connected to a piston  66 . 
     As shown in FIGS. 7 and 9, the cylinder mechanism  64  has a first cylinder  64   a  (upper side) and a second cylinder  64   b  (lower side). A partition plate  69  is formed between the first cylinder  64   a  and the second cylinder  64   b . The cylinder mechanism  64  is divided into an upper cylinder chamber A, B (first and second air chambers) and a lower cylinder chamber C, D (third and fourth air chambers) by the partition plate  69 . 
     In the first cylinder  64   a , a first piston  66  and a rod  65  are liftably provided. The inner space of the first cylinder  64   a  is divided into a first air chamber A (upper chamber) and a second air chamber B (upper chamber) by the first piston  66 . Note that the first piston  66  moves from a lower stepped portion  64   c  to an upper stepped portion  64   d  of the first cylinder  64   a . The stroke L 4  is 450 to 500 mm. Furthermore, the second piston  68  moves between a lower stepped portion  64   e  and an upper stepped portion  64   f  of the second cylinder  64   a . The stroke L 3  is 220 to 250 mm. 
     To detect the positions of the first and second pistons  66 ,  68 , respectively, three magnet sensors  121 ,  122 ,  123  are attached to the outer walls of the cylinders  64   a ,  64   b . The first sensor  121  is attached to the wall at a distance of L 4  from the lower stepped portion  64   c  (i.e., near the upper stepped portion  64   d ). The second sensor  122  is attached to the wall at a distance of L 3  from the lower stepped portion  64   c  of the first cylinder  64   a . The third sensor  123  is attached to the wall at a distance of L 3  from the lower stepped portion  64   e  of the second cylinder  64   b  (i.e., near the upper stepped portion  64   f ). 
     To each of the pistons  66 ,  68 , a permanent magnet (not shown) is buried. When the pistons  66 ,  68  face the magnet sensors  121 ,  122 ,  123  with the cylinder wall interposed therebetween, a magnet flux leaking from each of the permanent magnets is detected by the sensors  121 ,  122 ,  123  and the detection signal is sent to the controller  201 . 
     A pipe  71  is attached to the upper portion of the first cylinder  64   a  and a pipe  72  is attached to the lower portion of the first cylinder  64   a . These pipes  71  and  72  communicate with an air supply system  200  (see FIG. 12) described later. Air is introduced into and discharged from the first air chamber A and the second air chamber B by way of the flow passages  71   a  and  72   a , respectively. 
     In the second cylinder  64   b , a second piston  68  and a rod  67  are liftably provided. The inner space of the second cylinder  64   b  is divided into a third air chamber C (upper air chamber) and a fourth air chamber D (lower air chamber) by the second piston  68 . 
     A pipe  70  is attached to the upper portion of the second cylinder  64   b  and a pipe  73  is attached to the lower portion of the second cylinder  64   b . The pipes  70  and  73  communicate with the air supply system  200  (see FIG. 12) described later. Air is introduced into and discharged from the third air chamber C and the fourth air chamber D by way of flow passages  70   a  and  73   a , respectively. 
     A through-hole is formed at the center of the partition plate  69 . The second rod  67  goes into and out of the second air chamber B of the first cylinder  64   a  through the through-hole. A V seal  69   a  is provided between the second rod  67  and the partition plate  69 . The V seal protects air leakage between the second air chamber B and the third air chamber C. The V seal is low in frictional resistance, and therefore, the second rod  67  can slide smoothly through the through-hole of the partition plate  69 . 
     The second rod  67  is longer than the second cylinder  64   b , so that the tip portion of the rod  67  is always present within the second air chamber B. The second rod  67  and the piston  68  are mutually connected. Similarly, the first rod  65  is connected to the piston  66 . However, the second rod  67  is not connected to (that is, separated from) the first piston  66 . The second rod  67  can be sometimes in contact with the first piston  66 , as shown in FIGS. 9 and 10, and sometimes separated from the first piston  66 , as shown in FIG.  11 . 
     Next, referring to FIGS.  9 - 11 , we will explain how to operate the cylinder mechanism  64  when air is supplied. 
     As shown in FIG. 9, when air is not supplied to the flow passages  71   a ,  72   a ,  73   a , both first and second pistons  66 ,  68  are positioned at the lowest positions (lower dead center) of the first and second cylinders  64   a ,  64   b  while the upper end of the second rod  67  is in touch with the lower center portion of the first piston  66 . 
     When air of a pressure P 2  is supplied to the fourth air chamber D, as shown in FIG. 10, the second piston  68  is moved up and the second rod  67  comes into contact with the first piston  66  to push up the first piston  66 . At the same time, air of a pressure P 1  is supplied to the second air chamber B, thereby applying an ascendable force to the first piston  66 . By virtue of the ascendable force, the lid  42  is lifted up from a first position PS 1  (the position of the cup CP) to a second position PS 2  (position of the lid opened during the substrate processing time), as shown in FIG.  17 . 
     As shown in FIG. 11, when the pressure P 2  air is supplied to the second air chamber B, the first piston  66  is further moved up to the upper dead center of the first cylinder  64   a . As a result, the lid  42  is raised from the second position PS 2  to a third position PS 3  (position of the lid opened during the maintenance operation time). 
     In this case, the pressure P 1  air is supplied from the flow passage  72   a  to the second air chamber B and the pressure P 2  air is supplied from the pipe  73  to the fourth air chamber D. The pressures P 1  and P 2  have the relationship represented by the following inequality (1): 
     
       
         P 1 &lt;W&lt;P 2   (1) 
       
     
     where P 1  is a pressure of air to be supplied to the first cylinder  64   a  (second air chamber B), W is a pressure of air required for lifting the support arm  61  and the lid  42 , and P 2  is a pressure of air to be supplied to the second cylinder  64   b  (fourth air chamber D). 
     With this mechanism, an upwardly and vertically working driving force is applied to both first and second pistons  66 ,  68 . At this point, the second piston  68  is driven by the pressure P 2  air since the relationship “W&lt;P 2 ” represented by the inequality (1) is satisfied. Therefore, the support arm  61  and the lid  42  can be lifted up by means of the second piston  68  alone. 
     On the other hand, the upwardly and vertically working driving force is also applied to the first piston  66 . The driving force is produced due to the supply of the pressure P 1  air. In this case, the air pressure W is smaller than the air pressure W (P 1 &lt;W) as represented by the inequality (1). Therefore, the support arm  61  and the lid  42  cannot be lifted up by the first piston  66  alone. 
     As a result, the support arm  61  and the lid  42  are lifted up by a stroke L 3  of the second piston  68  by the cylinder mechanism  64  as a whole. The first and second pistons  66 ,  68  are moved upward by the same stroke L 3  while leaving the second rod  67  in contact with the first piston  66 . 
     As described, a load to lift up the support arm  61  and the lid  42  is imposed mainly on the second cylinder  64   b  (lower cylinder) has during general substrate processing time. In this case, the first piston  66  is pushed up by the second rod  67 . Note that driving force is also applied to the first piston  66  from the first cylinder  64   a , even if it works auxiliarily. Therefore, the speed for lifting up the support arm  61  and the lid  42  by the first and second cylinders  64   a ,  64   b  is faster than that by the second cylinder  64   b  alone. 
     Now, referring to FIGS. 11,  19 ,  20 , we will explain how to open and close the lid  42  during the maintenance operation time. 
     First, the pressure P 1  air is supplied from the flow passage  72   a  into the second air chamber B; at the same time, the pressure P 2  air is supplied from the flow passage  73   a  to the fourth air chamber D. As a result, the lid  42  is lifted up from the first position PS 1  to the second position PS 2 . 
     Then, the circuit of the air supply system  200  is switched. More specifically, while maintaining the pressure of the pressure P 2  air supplied from the flow passage  73   a , the pressure of the air supplied from the flow passage  72   a  is changed from P 1  to P 2 . By this switching operation, a sufficient magnitude of driving force to lift the support arm  61  and the lid  42  is applied to the first piston  66 . Consequently, the first piston  66  starts lifting up the support arm  61  and the lid  42  by itself. 
     Finally the first piston  66  is moved up to the upper dead point of the first cylinder  64   a  and then stopped, as shown in FIG.  11 . In this case, the support arm  61  is lifted up by the first piston  66  alone. However, since the pressure P 2  air alone is used as the driving source, the speed for lifting up the lid during the maintenance operation time is slower than that during the substrate processing time. However, the time period required for opening the lid  42  is short compared to the entire maintenance operation time. Therefore, it is acceptable even if the lid is lifted slower. 
     As described, the first rod  65  is much longer than the second rod  67 . Therefore, the support arm  61  can be lifted up to a sufficient level to ensure a space for the maintenance operation between the lid  42  and an upper frame of the coating apparatus  21 A. 
     Next, referring to FIGS.  12  and  9 - 11 , we will explain the air supply system  200  for supplying air to the cylinder mechanism  64 . 
     The air supply system  200  has a controller  201  for controlling operation of the various elements (fluid machines). When the cup lifter  60  is mistakenly operated, the controller  201  sends a signal to an alarm system  204  to ring the alarm  206 , thereby notifying that the abnormal operation takes place. At the same time, the controller  201  sends a signal for terminating the abnormal operation to a cup lifter driving portion. 
     A pipe  71  communicates with the first air chamber A positioned at the upper portion of the first cylinder  64 a. The pipe  71  communicates with a solenoid valve (SOLV)  94  by way of a speed controller (SC)  74 , a pipe  77 , a pilot check valve (PCV)  78 , a pipe  80 , a quick exhaust valve (QEV)  105 , a pipe  84 , a speed controller (SC)  88  and a pipe  96 . The solenoid valve (SOLV)  94  has a supply pipe  101  and an exhaust pipe  102 . The supply pipe  101  communicates with a supply port of the air supply source  202 . Furthermore, a pipe  97  of the solenoid valve (SOLV)  94  communicates with the fourth air chamber D positioned at the lower portion of the second cylinder  64   b.    
     The pipe  72  communicates with the second air chamber B positioned at the lower portion of the first cylinder  64 a. The pipe  92  communicates with a shuttle valve (SHV)  110  by way of a speed controller (SC)  75 , a pilot check valve (PVC)  79 B and a pipe  92 . The shuttle valve (SHV)  110  has a valve chamber  110   a  and a ball valve body  111 . Three pipes  86 ,  91  and  92  communicate with a valve chamber  110   a . The first pipe  86  communicates with a speed controller (SC)  87 . The speed controller (SC)  87  communicates with the solenoid valve (SOLV)  93  by way of a pipe  95 . The solenoid valve (SOLV)  93  has a supply pipe  99  and an exhaust pipe  100 . Furthermore, the solenoid valve (SOLV)  93  has a pipe  98  required for switching the supply line to the exhaust line. The end of the pipe  98  is opened to atmosphere. 
     The second pipe  91  communicates with an inlet side of the regulator (REG)  103 . A pipe  90  communicates to the outlet side of the regulator (REG)  103 . The pipe  90  merges with the pipe  85  in the middle way from the solenoid valve (SOLV)  94  to the fourth air chamber D positioned at the lower portion of the second cylinder  64   b . The third pipe  92  communicates with the second air chamber B positioned at the lower portion of the first cylinder  64   a  by way of the pilot check valve (PCV)  79 B, the speed controller (SC)  75  and the pipe  72 . 
     The pipe  70  communicates with the third air chamber C positioned at the upper portion of the second cylinder  64   b  and opened to air by way of a pipe not shown. On the other hand, the pipe  73  positioned at the lower portion of the second cylinder  64   b  communicates with the fourth air chamber D. The pipe  73  communicates with the solenoid valve (SOLV)  94  by way of a speed controller (SC)  76 , a pipe  104 , a pilot check valve (PCV)  79 A, a pipe  83 , a quick exhaust valve (QEV)  106 , a pipe  85 , a speed controller (SC)  89 , and a pipe  97 . 
     Next, referring to FIGS.  13 - 15 , various elements used in the circuit of the air supply system  200  will be explained. 
     The solenoid valves (SOLV)  93  and  94  are valves electrically driven and responsible for initiating and terminating supply and exhaust of the air and for switching the flowing direction of the air through the pipe back and forth. 
     As shown in FIG. 13, each of the speed controllers (SC)  74 ,  75 ,  76 ,  87 ,  88 ,  89  is a flow amount controller having a needle  166  between an inlet  77 , ( 92 ,  95 ,  96 ,  97 ,  104 ) and an outlet  71 , ( 72 ,  73 ,  84 ,  85 ,  86 ). The inlet  77  ( 92 ,  95 ,  96 ,  97 ,  104 ) of a main body ( 161 ) is crossed at a right angle with the outlet  71  ( 72 ,  73 ,  84 ,  85 ,  86 ). The needle  166  is attached to the main body  161  via a body ring  162 , a sheet ring  163 , a guide  164 , and a rock nut  165 . When the handle  167  is turned, the tip of the needle  166  touches on and off a U-shape packing  168 , so that a sectional area of the passage varies. 
     As shown in FIG. 14, each of the quick exhaust valves (QEV)  105 ,  106  includes a main body  171  having an inlet  84  ( 85 ), an outlet  80  ( 83 ), and an emergency exhaust port  81  ( 82 ), a flexible valve  172 , a first valve seat  173 , and a second valve seat  175 . When the quick exhaust valve (QEV) is used during the normal operation time, the flexible valve body  172  is in contact with the first and second valve seats  173 ,  175  while closing the emergency exhaust port  81  ( 82 ). The fluid therefore flows from the inlet  84  ( 85 ) to the outlet  80  ( 83 ). In the case where evacuation should be made efficiently in a short time, the flexible valve body  172  is separated from the first valve seat  173  to thereby open the emergency exhaust port  81  ( 82 ). Consequently, the fluid flows from the inlet  84  ( 85 ) toward the emergency exhaust port  81  ( 82 ). Since the emergency exhaust port  81  ( 82 ) has a diameter larger than a narrowed portion  174  of the outlet  80  ( 83 ), fluid can be discharged from the emergency port at high speed for a short time through the emergency outlet. 
     As shown in FIG. 15, each of the pilot check valves (PVC)  78 ,  79 B ( 79 A) has valve body  183  ( 184 ) serving as a security device in case of occurrence of abnormal pressure. A port  181   a  of the check valve  78  communicates with the first air chamber A. A port  182   a  of the other check valves  79 B ( 79 A) communicates with the second air chamber B (the fourth air chamber D). The valve bodies  183 ,  184  are slidably provided in order to open/close the inner passages  181   d ,  182   d , respectively. The flow passage  80  communicates with both a port  181   c  of the check valve  78  and a pilot pressure port  182   b  of the check valve  79 B. The flow passage  92  communicates with both a port  182   c  of the check valve  79 B and a pilot pressure port  181   b  of the check valve  78 . When supply of a pressurized fluid is shut out from the flow passages  80 ,  92  ( 83 ), the pilot check valves (PVC)  78 ,  79 B ( 79 A) of this type shut the inner flow passages  181   d ,  182   d , thereby preventing the pressurized fluids present in the first, second and fourth chambers A, B, D from flowing toward the flow passages  80 ,  92  ( 83 ). In this way, inner pressures of the first, second and fourth air chamber A, B, D are maintained as they are. 
     The shuttle valve (SHV)  110  is responsible for communicating one of two pipes  86 ,  91  at the input side with the pipe  92  at the output side. In the small chamber  110   a  of the shuttle valve (SHV)  110 , a shuttle  111  is movably set. Pipes  86  and  91  are respectively arranged at both sides of the small chamber  110   a  so as to face each other. The pipe  92  is connected to the middle of the small chamber  110   a . If air supplied from two pipes  86 ,  91  differs in pressure, the shuttle  111  is pushed from the pipe of a high-pressure side to the pipe of a low-pressure side, thereby allowing the communication between the high pressure pipe and the pipe  92 . As a result, the air flows from the high pressure side to the pipe  92 . As described, the shuttle valve (SHV)  110  is responsible for switching the flow passage by air pressure. 
     The regulator (REG)  83 , which is a kind of pressure reduction apparatus, plays a role in reducing the supplied air slightly and outputting the reduced air. 
     Next, referring to FIG. 16, a series of resist processing processes of the LCD substrate G will be explained. 
     A single substrate G is taken out form the cassette C 1  by a sub-transfer arm  13 . The substrate G is transferred from the sub transfer arm  13  to the first main transfer arm  14 A. The first main transfer arm  14 A transfers the substrate G from the brush washing unit  16 , the adhesion unit  24  and the cooling unit  25  subsequently. In individual units, predetermined treatment is applied to the substrate G. After a series of predetermined treatments is completed, the first main transfer arm  14 A transfers the substrate G to the second main transfer arm  14 B. Furthermore, the second main transfer arm  14 B transfers the substrate G to the unit  21 . When the second main transfer arm  14 B arrives in front of the resist coating section  21 A, a shutter (not shown) is open to load the substrate G into a resist coating section  21 A. 
     Subsequently, the lid  42  is opened by actuating the air cylinder mechanism  64  (Step  1 ). To open the lid  42 , the solenoid valve (SOLV)  94  is first actuated to communicate the flow passage of the pipe  101  with the flow passage of the pipe  97 . Since compressed air is supplied from an air supply source (air compressor)  202  to the pipe  101 , the compressed air is supplied to the speed controller (SC)  89  by way of the solenoid valve (SOLV)  94 . If the air supplied from the air compressor  202  has a pressure, for example, 4.5 kg/cm 2 , the compressed air of 4.5 kg/cm 2  is also supplied to the pipe  85 . Since the pipe  85  is branched off in the middle way toward the pipe  90 , the air is divided into an air flow heading for the quick exhaust valve (QEV)  106  and an air flow heading for the regulator (REG)  103 . 
     The compressed air heading for the quick exhaust valve (QEV)  106  is supplied to the fourth air chamber D of the second cylinder  64   b  by way of the quick exhaust valve  106 , the pipe  83 , the pilot check valve (PVC)  79 A, the pipe  104 , the speed controller (SC)  76  and the pipe  73 . Hence, the pressure of the air supplied to the air chamber D is 4.5 kg/cm 2 . This pressure serves as a force to lift up the second piston  68 . 
     On the other hand, the air flow heading for the regulator (REG)  103  flows into the regulator (REG)  103  by way of the pipe  90 . The air passing through the regulator (REG)  83  is reduced in pressure. For example, the air flowing from the pipe  90  at a pressure of 4.5 kg/cm 2  is reduced to 1.5 kg/cm 2  and flows out to the pipe  91 . The air flowing into the pipe  91  is sent to the shuttle valve (SHV)  110 . At this time, since no air is supplied into another input pipe  86  of the shuttle valve (SHV)  110  from the solenoid valve  93 , the air applied to the shuttle  111  is that supplied from the pipe  91 . The shuttle  111  is pushed by the air and moves within the small chamber  110   a . As a result, the pipe  91  communicates with the pipe  92  and the air flows into the pipe  92 . The air flowing into the pipe  92  is supplied into the second air chamber B positioned at the lower portion of the first cylinder mechanism  64 a by way of the speed controller (SC)  75  and the pipe  72 . Hence, the pressure of the air supplied to the second air chamber B is 1.5 kg/cm 2 . This pressure serves as a force to lift up the first piston  66 . 
     Note that the flow passage  70   a  is communicated with the third air chamber C (upper space of the second cylinder  64   b ) at the upstream and opened to air at the downstream by way of another flow passage (not shown). Furthermore, the flow passage  71   a  communicates with the first air chamber A (upper space of the first cylinder  64   a ) at the down stream and communicates with the solenoid valve (SOLV)  94  by way of the speed controller (SC)  74 , the pilot check valve (PCV)  78 , the quick exhaust. valve (QEV)  105  and the speed controller (SC)  88 . The pipe  96  is connected to the pipe  102  of the exhaust-side at the solenoid valve (SOLV)  94 . Since the airs of the first air chamber A and the third air chamber C are quickly exhausted by way of the aforementioned passage, the first and second pistons  66 ,  68  are swiftly lifted up. 
     Note that the inner flow passage  181   d  of the PCV  78  is opened by virtue of a pilot pressure of the pressurized fluid supplied through the flow passage  92 . 
     As described, the second piston  68  is driven by the air of a pressure of 4.5 kg/cm 2  and the first piston  66  is driven by the air of a pressure of 1.5 kg/cm 2 . The 4.5 kg/cm 2  air works to lift up the lid  42  in concert with the 1.5 kg/cm 2  air. 
     In this case, provided that the force due to the air of 4.5 kg/cm 2  in pressure for pushing up the second piston  68  is indicated by 4.5P, the force due to the air of 1.5 kg/cm 2  in pressure for pushing up the first piston  66  is indicated by 1.5P, and the pressure (force) required for lifting up the supply arm  61  and the lid  42  is indicated by W, the following relationship represented by inequality (1) is obtained 
     
       
         1.5P&lt;W&lt;4.5P  (1) 
       
     
     Therefore, the lid  42  stops after moved up by the stroke L 3  of the second piston  68 . In this case, the lid  42  moves up faster than the case of using the second cylinder  64   b  alone. Note that the second position PS 2  is a position which can provide a space between the lid  42  and the cup CP,  41 , sufficient for the holder  14   b  of the main arm mechanism to go in and out. 
     Note that when an instruction signal is sent from the controller  201  to each of machines provided in the circuit of the system  200 , operation of each of machines is interlocked upon receipt of the signal. Therefore, the lid  42  stops at the second position PS 2 . In addition, the lifting operation of the lid  42  is mechanically limited also by the presence of the shock absorber  190 C. Hence, the lid  42  cannot be moved up over the second position PS 2 . Before the loading/unloading operation is initiated, the output from the sensor is checked. In the case where abnormality is found, the controller  201  actuates an alarm system  204 ; at the same time, immediately terminates the air supply and the exhaust operation. when the abnormality takes place, the substrate under processing in other processing section is at least completed and the processing operation is continuously performed as much as possible. On the other hand, the unprocessed substrate is temporarily stored in a vacant space of the buffer cassette or processed in another processing apparatus in the case where the coating apparatus consists of a plurality of apparatuses. 
     When the cover  42  stops at the second position PS 2 , the spin chuck  43  is moved up to transfer the substrate G from the arm holder  14 b to the spin chuck  43 . The arm holder  14   b  is allowed to withdraw, and then, the shutter is closed. The spin chuck  43  is moved down while absorbing and holding the substrate G by the spin chuck  43  (Step S 2 ). 
     Air is supplied to the first air chamber A of the air cylinder mechanism  64  to move down the first piston  66 ; at the same time, air is supplied to the third air chamber C to move down the second piston  68 . Then, the cup is covered by the lid  42 , as shown in FIG. 18 (Step S 3 ). 
     Now, how to close the lid  42  will be explained. 
     First, operation of the solenoid valve (SOLV)  94  is switched. More specifically, the communication between the pipe  97  and the supply pipe  101  is changed to the communication between the pipe  97  and the exhaust pipe  102 . Since no air is supplied from the pipe  101 , the weight of the support arm  61  and the lid  42  is applied downwardly onto the second piston  68  via the first piston  66 . As a result, the first piston no longer supports the support arm  61  and the lid  42  and starts descending. Then, the air within the fourth air chamber D is sent to the quick exhaust valve (QEV)  106  by way of the pipe  73 , the speed controller (SC)  76 , the pipe  104 , the pilot check valve (PCV)  79 A, and the pipe  83 . The flow passage of the quick exhaust valve (QEV)  106  communicates with the pipe  82 , exhausting the air toward the pipe  82 . Since the pipe  82  is wide in diameter, air is swiftly exhausted from the fourth air chamber D, with the result that the second piston  68  moves down quickly. 
     At this time, the inner flow passage  182   d  of the PVC  79 A is opened by virtue of the pressurized fluid supplied through the flow passage  80 . 
     On the other hand, when the air supplied to the fourth air chamber D from the pipe  101  is terminated, the first piston  66  of the first cylinder  64   a  is no longer lifted up. The weight of the support arm  61  and the lid  42  is applied onto the first piston  66 . Hence, the air of the second air chamber B is introduced into the shuttle valve (SHV)  110  by way of the pipe  72 , the speed controller (SC)  75 , a pilot check valve (PCV)  79 B and the pipe  92 , and further introduced into the pipe  85  by way of the pipe  91 , the regulator (REG)  103 , and the pipe  90 . Since the air introduced into the pipe  85  is sent to the pipe  82  by way of the quick exhaust valve (QEV)  106  in the similar manner, with the result that evacuation is swiftly made through the pipe  82 . As a result, the first piston  66  moves down quickly. At this time, the inner flow passage  182   d  of the PVC  79 B is opened by virtue of the pressurized fluid supplied through the flow passage  80 . 
     When the support arm  61  moves down to the lowest position, the lower surface of the support arm  61  comes into contact with the shock absorber  190 B. The damper of the shock absorber  190 B is slightly and upwardly urged from the descending and stopping position. When the weight of the lid  42  and the support arm  61  is applied to the damper, the shock absorber attached to the lower portion of the damper is distorted. As a result, the descending speed of the lid  42  becomes slow and therefore the lid  42  is moved down slowly and fixed at the cup CP. Since the descending speed of the lid  42  is reduced as mentioned, the lid  42  does not damage the cup CP. 
     After the lid  42  is closed, the temperature of the substrate G placed within the closed cup CP is controlled (Step  4 ). After the temperature control is completed, the lid  42  is opened (Step S 5 ) and the arm  155  is rotated to position the nozzle  157  immediately above the center of the substrate G. While rotating the substrate G at low speed, a solvent is supplied (Step S 6 ) to the substrate G from the nozzle  157  (Step S 6 ). The lid  42  is closed (Step S 7 ) and the substrate G and the cup  41  are synchronously rotated to disperse the solvent over the surface of the substrate G (Step S 8 ). Since the substrate G and the cup are rotated synchronously, substantially no air flow is generated around the substrate G, the temperature of the solvent is equalized. 
     The lid  42  is opened (Step S 9 ), the nozzle  157  is set right above the center of the substrate G, and a resist solution is supplied to the substrate G from the nozzle  157  (Step S 10 ). Then, the lid  42  is closed (Step Sll), evacuation of the drain cup  41  is started. Simultaneously, the substrate G is rotated in synchronism with the cup CP to disperse the resist solution over the surface of the substrate G (Step S 12 ). 
     The lid is opened (Step S 13 ) and the spin chuck  43  is moved up to transfer the substrate G onto the transfer mechanism  262 . The transfer mechanism  262  unloads the substrate G from the resist coating section  21 A and transfers it toward the peripheral coating film removing section  21 B (Step S 14 ). After the transfer mechanism  262  is withdrawn, the spin chuck  43  is moved down and the lid  42  is closed (Step S 15 ). 
     In the peripheral coating film removing section  21 B, the table  230  is moved down to transfer the substrate G from the transfer mechanism  262  onto the table  230 . The transfer mechanism  262  is withdrawn and the table  230  is moved down. While moving the nozzles  234  along the corresponding sides of the substrate G, the resist coating film is removed from the peripheral portion of the substrate G. Then, the table  230  is moved up and the substrate G is taken up from the table  230  by the second main transfer arm mechanism  14 B to unload it from the unit  21 . 
     Thereafter, the substrate G is transferred to the baking unit  26  and the cooling unit  27  by the second and third main transfer arms  14 B and  14 C. Predetermined treatments are performed in the units  26 ,  27 . Furthermore, the substrate G is loaded by the third main transfer arm  14 C into the light-exposure apparatus  6  via the interface section  7  in order to patternexpose the resist coating film by the light exposure apparatus  6 . 
     After light exposure treatment, the substrate G is transported to the development unit  28  to develop the pattern-exposed resist film. Furthermore, the substrate G is rinsed with pure water and dried up with heat. The substrate G is further transported to the cooling unit  33  to cool it. The processed substrate G is transferred to the first to third main transfer arms  14 A,  14 B,  14 C and the sub transfer arm  13 . The substrate G is placed into the cassette C 2  of the loader section  2  by the sub transfer arm  13 . Finally, the cassette  2  storing the substrates G is unloaded from the system  1 . The processed substrate G is transported to another processing apparatus used in a next step. 
     Next, referring to FIGS. 11,  19 ,  20 , how to perform the maintenance operation of the aforementioned apparatus will be explained. 
     In the resist coating section  21 A, the resist solution is scattered and attached onto individual portions such as the cup CP  41  to stain them. Therefore, if the resist coating section  21 A is operated continuously for a long time, it may be better to clean every portion of the apparatus. At the time of maintenance operation, members must be removed from the main apparatus. The removing operation is disturbed by the lid  42 . It is therefore necessary to ensure a sufficient operational space at the upper portion of the main apparatus. 
     First, the shock absorber  190 C is removed from the guide post  62 . The solenoid valve (SOLV)  94  is actuated to communicate the pipe  101  with the pipe  97 . In this manner, the air of 4.5 kg/cm 2  in pressure is sent to the pipe  97  and the fourth air chamber D, and the air of 1.5 kg/cm 2  in pressure, which has been reduced by the regulator (REG)  103 , is sent to the second air chamber B. In this way, the lid  42  is moved up to the third position PS 3 . 
     Subsequently, the solenoid valve (SOLV)  93  is actuated to communicate the pipe  99  and the pipe  95  to thereby supply the air of 4.5 kg/cm 2  in pressure to the pipe  95 . The air is introduced into the shuttle valve (SHV)  110  by way of the speed controller (SC)  87  and the pipe  86 . Since the air as high a pressure as 4.5 kg/cm 2  is supplied from the pipe  86  to the shuttle valve (SHV)  110  where the air of 1.5 kg/cm 2  has been supplied from the pipe  91 , the shuttle  111  is pushed to a lower pressure side, i.e., the pipe  91  side within the shuttle valve (SHV)  110 , by the newly supplied air of 4.5 kg/cm 2 . As a result, the pipe  86  communicates with the pipe  92 . Consequently, the air of 4.5 kg/cm 2  flows into the pipe  92  and further goes into the second air chamber B by way of the speed controller (SC)  75  and the pipe  72 . Hence, a driving force working vertically and upwardly is applied to the piston  66  due to the air of 4.5 kg/cm 2 . 
     As mentioned above, since there is a relationship: 
     
       
         1.5P&lt;W&lt;4.5P 
       
     
     the lid  42  and the support arm  61  are lifted up by the force of the air. As shown in FIG. 19, the lid  42  is moved up to the third position PS 3  and maintained as it is. Note that the first piston  66  moves up independently of the second rod  67 , as shown in FIG.  11 . 
     As explained, the maintenance operation is performed while maintaining the lid  42  at the highest position to be attained. The lid  42  is moved down after completion of the maintenance operation. 
     Now, how to descend the lid  42  will be explained. 
     First, operation of the solenoid valve (SOLV)  93  is switched to communicate the pipe  95  with the pipe  100  of the exhaust side. Since no air is supplied from the pipe  99 , the driving force working vertically and upwardly is no longer applied to the first piston  66 . The weight of the lid  42  and the support arm  61  is applied downwardly. Due to this weight, the first piston  66  is moved down. The air of the second air chamber B therefore flows into the shuttle valve (SHV)  110  by way of the pipe  72 , the speed controller (SC)  75  and the pipe  92 . Since the shuttle  111  is placed at the pipe  91  side within the shuttle valve (SHV)  110 , the air flows into the pipe  86  and arrives at the solenoid valve (SOLV)  93  by way of the speed controller (SC)  87  and the pipe  95 . In the solenoid valve (SOLV)  93 , since the pipe  95  communicates with the exhaust pipe  100 , the air is exhausted through the exhaust pipe  100 . As a result, the first piston  66  moves down and the bottom of the piston  66  comes into contact with the second rod  67 . 
     Prior to this, the solenoid valve (SOLV)  94  plays a role in communicating the pipe  97  with the exhaust valve  102  in synchronism with the solenoid valve (SOLV)  93 . Therefore, the air supply from the pipe  101  to the fourth air chamber D, is stopped. Since the force driving the second piston  68  upwardly is no longer applied, the second piston  68  starts descending due to the force of the second piston  68  upon descending the first piston  66 . 
     As a result, the inner air of the fourth air chamber D flows into the pipe  73  and further introduced into the quick exhaust valve  106  by way of the speed controller (SC)  76 , the pipe  104 , the pilot check valve (PVC)  79 A and the pipe  83 . In the quick exhaust valve  106 , the pipe  83  communicates with the pipe  82 , so that the air flowing into the quick exhaust valve (QEV)  106  is introduced into the pipe  82  and swiftly exhausted through the pipe  82 . Since the air within the fourth air chamber D is swiftly exhausted through the pipe  82 , the lid  42  can be moved down quickly. 
     In case of the power supply is shut out and thereby the air supply is terminated, the air supply to the second air chamber B is still maintained by virtue of the PCV  79 B (that is, the air is shut in the second air chamber), so that the lid  42  is not moved down. 
     According to the aforementioned embodiment, it is possible to change the height of the lid  42  lifted during the substrate processing time and the maintenance operation time. Hence, the maintenance operation can be performed simply and securely without taking the apparatus apart. 
     According to he aforementioned embodiment, the lid  42  can be raised at high speed and thereby operated smoothly. 
     Furthermore, in the case of descending the lid  42 , the air is exhausted through the quick exhaust valves (QEV)  105 ,  106  at high speed, with the result that air can be exhausted from the air cylinder  64  quickly. Hence, the lid  42  can be moved down at high speed and closed securely. 
     In the aforementioned embodiment, the coating apparatus for coating resist on the LCD substrate has been explained. However, any apparatus can be used as long as it is a substrate processing apparatus with a lid. Hence, the present invention can be applied to other apparatuses including a developing apparatus. The present invention can be further applied to an apparatus for coating a resist solution onto the semiconductor wafer and developing the coated resist. 
     Furthermore, in the aforementioned embodiment, the cylinders  64   a ,  64   b  are moved by supplying air to the second air chamber B and the fourth air chamber D positioned at the lower portions of the cylinders  64   a ,  64   b , respectively. However, the cylinders  64   a ,  64   b  may be moved by applying a negative pressure simultaneously to the first air chamber A and the third air chamber C at the upper portions of the cylinders  64   a ,  64   b.    
     Furthermore, in the general manufacturing step mentioned above, the lid  42  may be moved up by use of the air supply in combination with the application of the negative pressure and moved down by use of natural exhaustion in combination with the application of the positive pressure. 
     Furthermore, the present invention is not limited to the aforementioned embodiments. The first lifting mechanism and the second lifting mechanism are arranged in parallel and the support arm  61  may be lifted by either the first lifting mechanism or the second lifting mechanism. In this case, an inner diameter of the cylinder of the first lifting mechanism may be set differently from that of the cylinder of the second lifting mechanism. 
     Next, referring to FIGS.  21 - 24 , the substrate processing apparatus according to another embodiment will be explained. Note that detailed explanation will be omitted for the portions of this embodiment overlapping with the aforementioned embodiment. 
     As shown in FIG. 21, an auxiliary lifting mechanism  300  is provided in parallel to the air cylinder mechanism  64  in the guide post  62 . The auxiliary lifting mechanism  300  has two pulleys in each of the upper and lower portions. More specifically, four pulleys,  344 ,  345 ,  346 , and  347  are provided in total. The second pulley  345  is arranged immediately bellow the first pulley  344 . The fourth pulley  347  is arranged immediately below the third pulley  346 . A belt  348  is stretched between the first and second pulleys and a belt  349  is stretched between the third and fourth pulleys. To one end of each of the two belts  348  and  349 , a root portion  61   c  of the support arm  61  is fastened by a fastening member  350 . 
     To the other end of each of the two belts  348 ,  349 , a weight  352  is attached. The weight  352  serves as a balancer to keep the balance between the weight of the support arm  61  and the lid  42 , When the support arm  61  is positioned at the lowest point, the weight  352  is positioned at the highest point. The weight  352  is liftably guided along the guide rails  353 ,  354 . When the support arm  61  is moved down, the weight  352  is raised. On the contrary, when the support arm  61  is lifted up, the weight  352  moves down. 
     Note that the upper pulleys  342 ,  344  are arranged at positions higher than the air cylinder mechanism  64 . The weight  352  may be heavier than the total weight of the lid  42  and the support arm  61 . 
     According to the present invention, it is possible to perform the maintenance operation simply and securely without taking the apparatus apart. In addition, according to the present invention, it is possible to move up and down the lid swiftly during the substrate processing time. 
     Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.