Abstract:
An apparatus for cleaning a whole substrate by ejecting a cleaning liquid from a nozzle while rotating the substrate, the apparatus comprising: two or more linear reciprocating driving sources capable of generating outputs independently of one another; a rotation shaft; two or more cam mechanisms for converting the outputs into rotating forces; two or more sets of rotation columns fixed to the rotation shaft rotatably about their respective axes to horizontally support the substrate and sandwich or release the side surface of the substrate in cooperation with one another along with their rotation; two or more transfer members capable of transferring the rotating force to the sets of rotation columns in conjunction with the cam mechanisms, respectively; and a stopper causing the rotation of the cam mechanisms to be related to the rotation of the rotation shaft.

Description:
TECHNICAL FIELD  
       [0001]     The present invention relates to an apparatus capable of cleaning the surface, the back surface and the outer peripheral surface of a substrate and can be preferably used for cleaning a precision substrate, such as a semiconductor substrate, a liquid crystal glass substrate, a mask substrate.  
       BACKGROUND ART  
       [0002]     As an apparatus for cleaning a substrate, there has been conventionally known an apparatus as illustrated in  FIG. 11  (for example, JP-A No. 8-299918). The apparatus  101  basically includes a table  102  for holding a substrate  150  by sucking the back surface thereof with a vacuum pump which is not illustrated, a motor  125  for rotating the table  102  with respect to the apparatus main body, and a cleaning-liquid ejecting nozzle which can be revolved above the table  102 .  
         [0003]     Further, a cleaning liquid is ejected from the ejection nozzle for cleaning the surface of the substrate  150 , while the ejection nozzle is reciprocated in the radial direction of the table  102  with respect to the substrate  150  being rotated along with the table  102 . During the cleaning, the substrate  150  is surrounded by a cover  110 , thereby preventing the cleaning liquid from scattering. When the back surface is cleaned, the evacuation is temporarily stopped, and an operator reverses the substrate  150  with his or her power using gloves, or extracts the substrate  150  on a carrying-out table  161 , reverses it with a reversing device (for example, JP-A No. 2003-7663), then introduces it into the apparatus main body on a carrying-in table  160  and performs the cleaning operation, again. When carrying out and carrying in, the cover  110  is pushed up to the upper withdrawal position with an air cylinder  131 .  
         [0004]     As another conventional apparatus for cleaning a substrate, there has been suggested an apparatus which holds a substrate at the peripheral edge of a table having a center concave portion, places a lower nozzle within the concave portion and supplies a cleaning liquid to the lower nozzle through a pipe passing through the rotation shaft of the table (JP-A No. 11-156314). This apparatus can clean the back surface of the substrate with the cleaning liquid ejected from the lower nozzle, thereby eliminating the necessity of reversing the substrate. Further, although JP-A No. 11-156314 describes no means for securing the substrate on the table, it can be perceived, from the configuration illustrated in the figure, that the peripheral edge of the substrate is held by the table at plural positions individually.  
         [0005]     Both the apparatuses employ, in order to dry the substrate after cleaning, a method of increasing the rotation speed to about three times the rotation speed during cleaning for throwing off the cleaning liquid or, in some cases, employ a method of ejecting an alcohol such as isopropyl alcohol (IPA) to the substrate for reducing the drying time.  
         [0006]     However, in performing cleaning, the conventional cleaning apparatus illustrated in  FIG. 11  requires a longer time period to reverse the substrate  150 , thereby reducing the cleaning efficiency. Further, since the apparatus temporarily stops the rotation of the substrate before reversing it, in the case where the substrate is a printed circuit board, a conductive material may be scattered due to the pressure of the cleaning liquid and adhered to the surface and the back surface of the substrate, thereby contaminating the substrate, during the stoppage of the substrate. In the case where the conductive material is made of a low-resistance material such as copper, even a small amount of such a conductive material adhered to the substrate may induce short-circuits between wirings, thus reducing the yield of products. Further, it is difficult to clean the outer peripheral surface of the substrate. The apparatus disclosed in JP-A No. 11-156314 holds the peripheral edge of the substrate with the table at plural positions individually, which makes it difficult to attach or detach the substrate to or from the table.  
         [0007]     Next, regarding drying, when the aspect ratios of wiring trenches (grooves) are larger, water marks or IPA may be left in the trenches, which may cause corrosion or contamination of the conductive material, thereby increasing the electric resistances. In some cases, secondary contaminations may occur due to robot hands and the like. This makes it necessary to provide sufficient measures for preventing combustion of the alcohol.  
       DISCLOSURE OF THE INVENTION  
       [0008]     Therefore, it is an object of the present invention to provide an apparatus capable of cleaning the outer peripheral surface of a substrate while rotating the substrate. It is another object to provide an apparatus capable of cleanly drying a substrate after cleaning of the substrate.  
         [0009]     In order to attain the objects, according to the present invention, there is provided an apparatus for cleaning a substrate by ejecting a cleaning liquid from a nozzle while rotating the substrate, wherein the cleaning apparatus comprises a main body, two or more linear reciprocating driving sources capable of generating outputs independently of one another, a rotation shaft rotatably mounted to the main body, two or more cam mechanisms, two or more sets of rotation columns, two or more transfer members and a stopper.  
         [0010]     The cam mechanisms are mounted to the main body such that they are rotatable about the rotation shaft and convert the aforementioned outputs into rotating forces. The rotation columns have respective axes parallel to the rotation shaft at positions radially spaced from the center of the rotation shaft and are fixed to the rotation shaft rotatably about their axes to horizontally support a substrate and sandwich or release the side surface of the substrate in cooperation with one another, along with rotation thereof. The transfer members have a rotation center which is concentric with the rotation shaft and transfer the aforementioned rotating forces to the sets of the rotation columns in conjunction with the cam mechanism. The stopper is secured to the rotation shaft and causes the rotation of the cam mechanism to be related to the rotation of the rotation shaft.  
         [0011]     The apparatus according to the present invention has effects as follows. At first, a substrate is supported by the rotation columns and is sandwiched by one set of rotation columns (which is referred to as a set A and another set is referred to as a set B), out of the plural sets of rotation columns, while the rotation shaft is rotated. Consequently, the substrate is rotated, thereby enabling cleaning the substrate by ejecting a cleaning liquid thereto. At this stage, it is possible to clean the whole substrate except for the portions of the outer peripheral surface of the substrate which are in contact with the set A of the rotation columns. During this time, the transfer members and the cam mechanisms are also rotated together with the rotation shaft along with the stopper and, also, the respective rotation columns are revolved about a center axis which passes through the rotation shaft.  
         [0012]     Next, an output is generated from a driving source to rotate the set B of rotation columns through one of the cam mechanisms and one of the transfer members along a transfer path from the driving source to the set B of the rotation columns. Namely, the cam mechanism converts the output of the driving source into a rotating force and the rotating force is transferred to the set B of rotation columns through the transfer member. Along therewith, the set B of rotation columns being revolved are rotated about their axes. This causes the substrate to be sandwiched by the set B of rotation columns as well as the set A of rotation columns.  
         [0013]     Thereafter, the direction of the output from another driving source is changed to rotate the set A of rotation columns about their axes. Consequently, the substrate is released from the set A. This enables cleaning the portions which have been contacted with the set A of rotation columns and thus have been left uncleaned.  
         [0014]     The aforementioned rotation columns may include a column having an upper surface, and a pin which is erected at a decentered position on the upper surface and is brought into contact with the side surface of the substrate or separated therefrom along with the rotation of the column, because the bottom surface of the substrate can be supported by the upper surfaces of the columns while the side surface of the substrate can be sandwiched by the pins or released therefrom without damaging the side surface. In this case, the respective sets of pins are placed, such that the pins constituting each set are placed at substantially even intervals in the circumferential direction and are placed at phase positions different from the other sets of pins. Consequently, the respective sets of pins can alternately sandwich or release the substrate. In this configuration of the rotation columns, it is preferable that the aforementioned upper surfaces are inclined and the aforementioned decentered positions are the highest positions on the upper surfaces. This causes the upper surfaces to be contacted with the bottom surface of the substrate in a point-to-point contact, which allows the cleaning liquid to easily pass between the upper surfaces and the bottom surface of the substrate, thereby further improving the cleaning effect.  
         [0015]     The means for transferring the rotating force from the transfer members may be gear transmission and belt transmission. It is desirable to employ gear transmission, namely it is desirable to form gear teeth on the outer peripheral surfaces of the aforementioned rotation columns and form gear teeth on the outer peripheral surfaces of the transfer members such that these gear teeth are engageble with each other.  
         [0016]     The aforementioned cam mechanisms may be combinations of a grooved cam having a groove inclined with respect to the rotation shaft which is mounted rotatably with respect to the main body and movably in the direction of the rotation shaft and a roller which rotates within the groove and is secured to the corresponding transfer member. Since the groove is inclined with respect to the rotation shaft, the movement of the grooved cam in the direction of the rotation shaft displaces the roller in the circumferential direction, thereby rotating the transfer member.  
         [0017]     The aforementioned stopper may be a disk member which is orthogonal to the rotation shaft and has concave portions which allow the grooved cams to move in the direction of the rotation shaft and cause the grooved cams to rotate together with the rotation shaft.  
         [0018]     It is preferable that a table is secured to the upper end of the aforementioned rotation shaft and the aforementioned rotation columns are hermetically secured to the rotation shaft through the table, because components under the table can be prevented from being wetted. Further, it is preferable that the table extends outwardly in the radial direction from the rotation columns and there is provided a cover which can be hermetically contacted with the upper surface of the extended portion of the table and can house the rotation columns. This can house the substrate within an extremely narrow sealed space. This enables rapidly drying the substrate while halting the substrate at the position, by combining depressurization means and means for introducing a gas inert to the substrate material. Further, such a hermetic sealing configuration using a table and rotation columns can be applied to cleaning apparatus having, under a table, power transfer mechanisms different from that of the present invention.  
         [0019]     Namely, in order to attain the aforementioned second object, a preferable substrate drying apparatus includes a table, plural supporting columns erected between the center of the table and the peripheral edge thereof for supporting a substrate (in the case where the aforementioned cleaning apparatus is a compound apparatus which also serves as the drying apparatus, the rotation columns form the supporting columns), a cover which can be hermetically contacted with the upper surface of the table to house the supporting columns and is movable in such a direction that it is separated from the table, and means for depressurizing the space surrounded by the cover which is contacted with the table and the table.  
         [0020]     The substrate cleaning apparatus according to the present invention can clean an entire substrate including its outer peripheral surface while rotating the substrate. This can alleviate adhesion of a conductive material scattered due to the pressure of the cleaning liquid to the substrate, thereby improving the cleanliness of the cleaned substrate. Further, the entire apparatus has a smaller size, since there is provided no reversing/transferring devices for cleaning the surface and the back surface of a substrate. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0021]      FIG. 1  is an axial cross-sectional view illustrating a cleaning apparatus according to a first embodiment.  
         [0022]      FIG. 2  is a plan view illustrating main bodies of the same cleaning apparatus.  
         [0023]      FIG. 3  is a front view illustrating a grooved cam in the same cleaning apparatus.  
         [0024]      FIGS. 4A and 4B  are a plan view and a front view illustrating the relationship between a grooved cam and a stopper in the same cleaning apparatus, respectively.  
         [0025]      FIGS. 5A and 5B  are a plan view and a rear view illustrating the relationship between another grooved cam and the stopper in the same cleaning apparatus, respectively.  
         [0026]      FIG. 6  is a plan view illustrating a transfer member in the same cleaning apparatus.  
         [0027]      FIG. 7  is a plan view illustrating another transfer member in the same cleaning apparatus.  
         [0028]      FIG. 8  is a view illustrating the timing of rotations of a set of rotation columns and another set of rotation columns.  
         [0029]      FIG. 9  is an axial cross-sectional view illustrating a cleaning apparatus according to a second embodiment.  
         [0030]      FIG. 10  is an enlarged view of the portion D in  FIG. 9 .  
         [0031]      FIG. 11  is an axial cross-sectional view illustrating main parts of a conventional cleaning apparatus.  
         [0032]      FIG. 12  is an axial cross-sectional view illustrating a modified example of the cleaning apparatus according to the first embodiment.  
         [0033]      FIG. 13  is an axial cross-sectional view illustrating a modified example of the cleaning apparatus according to the second embodiment. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0034]     Embodiments of the present invention will be described with reference to the drawings.  
       First Embodiment  
       [0035]      FIG. 1  is an axial cross-sectional view illustrating a cleaning apparatus according to a first embodiment and  FIG. 2  is a main-part plan view of the same.  
         [0036]     The cleaning apparatus  1  is configured to eject a cleaning liquid while rotating a semiconductor substrate  70  to clean the semiconductor substrate  70 . The cleaning apparatus  1  includes a main body  43  having a cylindrical portion, a driving motor  9  secured to the main body  43 , a hollow rotation shaft  4  mounted via upper and lower bearings  30  to the inner peripheral surface of the cylindrical portion of the main body  43 , three reciprocating air cylinders  51  secured through a cylinder base  46  to the main body  43  at even intervals in the circumferential direction, and three reciprocating air cylinders  52  similarly secured through a cylinder base  47 . The driving motor  9  rotates the rotation shaft  4  about its axis through a belt. A disk-shaped table  3  is fastened to the upper end of the rotation shaft  4  with bolts. A center shaft  5  is fitted within the rotation shaft  4  through upper and lower bearings  7 , and two cleaning-liquid supply pipes are passed through the center shaft  5 . The center shaft  5  is protruded upwardly from the table  3 , and two lower nozzles  6  connected to the respective supply pipes are mounted to the upper end of the center shaft  5 , and the lower end of the center shaft  5  is secured to the main body  43 .  
         [0037]     The two sets of air cylinders  51  and  52  include rods which reciprocate in the upward and downward directions along with blocks  56  and  57  provided at their tip ends and are connected to a control device, which is not illustrated, such that the cylinders constituting each set operate in synchronization with one another and generate outputs independently of the other set of cylinders. An annular grooved cam  37  surrounding the cylindrical portion of the main body  43  is mounted to the block  57  through a bearing  32 , while another annular grooved cam  36  is mounted to the block  56  through a bearing  31  such that it surrounds the grooved cam  37 . Namely, the grooved cams  36  and  37  are placed in a double ring shape in a non contact manner. As illustrated in a front view of  FIG. 3 , three upward protrusions  40  are formed on the peripheral edge portion of the grooved cam  36  at even intervals in the circumferential direction and, further, protrusions  41  are formed on the peripheral edge portion of the grooved cam  37  at positions deviated in phase by 60 degrees from the protrusion  40 . Further, grooves  38  and  39  are radially formed through the protrusions  40  and  41 , wherein the grooves  38  and  39  are inclined in an upward-and-leftward direction when viewed from the outside. The inclination of the groove  38  is smaller than the inclination of the groove  39 , in order to make the rotation stroke of a transfer member  26  which will be described later equal to the rotation stroke of a transfer member  27 . Above the grooved cams  36  and  37 , a disk-shaped stopper  23  having an outer diameter greater than that of the grooved cam  36  is protruded in the radial direction from the outer peripheral surface of the rotation shaft  4 . The stopper  23  is fastened to the rotation shaft  4  with bolts. The stopper  23  has cutouts  24  and holes  25  for receiving the protrusions  40  and  41  with slight clearance at the positions corresponding to the protrusions  40  and  41 , as illustrated in  FIGS. 4A, 4B ,  5 A and  5 B. This allows upward and downward movements of the grooved cams  36  and  37  and also prevents the rotations of the grooved cams  36  and  37  relative to the rotation shaft  4 .  
         [0038]     On the other hand, three rotation columns  10  are mounted to the peripheral edge of the table  3  at even intervals in the circumferential direction and, further, rotation columns  11  are mounted to the same periphery at positions deviated in phase by 60 degrees from the rotation columns  10 . The three rotation columns  10  have the same shape. This also applies to the rotation columns  11 . The rotation columns  10  and  11  are rotatably penetrated through the table  3  in the vertical direction. Further, the upper surfaces of the rotation columns  10  and  11  are inclined with moderate gradients, and round-bar-shaped pins  20  and  21  are upwardly protruded at substantially highest positions of the upper surfaces. Gears  12  and  13  are fitted and secured to the rotation columns  10  and  11  at their portions under the table  3 . These gears  12  and  13  are engaged with gear teeth  28  and  29  formed on the outer peripheral surfaces of the transfer members  26  and  27 , respectively. The transfer members  26  and  27  have substantially a disk shape having an axial hole at the center, as illustrated in plan views of  FIGS. 6 and 7 . The transfer member  26  is made of a resin having a low friction coefficient such as a fluororesin and is slidably fitted to the outer peripheral surface of the rotation shaft  4  at a position just under the table  3 . The transfer member  27  is similarly fitted to the rotation shaft  4  at a position lower than the transfer member  26 . Further, the transfer members  26  and  27  are provided with concave-shaped relieves  71  and  72 , in order to prevent the transfer members  26  and  27  from interacting with the gears  13  and  12  which are not to be engaged therewith. Further, near the lower surfaces of the transfer members  26  and  27 , rollers  16  and  17  are mounted through brackets such that they are rotatable within the grooves  38  and  39  of the grooved cams. Further, the reference character  73  in  FIG. 7  designates holes for inserting the brackets therethrough.  
         [0039]     Above the table, there is provided an upper nozzle (not illustrated). The upper nozzle is similar to an ejecting device  30  disclosed in WO2005-38893, for example, and is held at an end portion of an arm, wherein the other end of the arm is connected to a joint such that it is rotatable about a horizontal axis, and the joint is rotatably erected on the main body. Accordingly, the upper nozzle can be moved in the horizontal direction and also can be inclined and is capable of ejecting the cleaning liquid toward the upper surface and the side surfaces of the substrate.  
         [0040]     Further, as illustrated in an axial cross-sectional view of  FIG. 12 , the transfer members  26  and  27  can be engaged with the rotation shaft  4 , with ball-and-roller bearings  60  and  61  interposed therebetween.  
         [0041]     There will be described the operation for cleaning a circular substrate  70  using the cleaning apparatus  1 . In the following description, the terms “clockwise direction” and “counter clockwise direction” refer to “the clockwise direction in a plan view” and “the counter clockwise direction in a plan view”, respectively. The substrate  70  is placed on the upper surfaces of the rotation columns  10  and  11 , while the motor  9  is kept at an OFF state, the rotation of the table  3  is kept stopped and the pins  20  and  21  are kept withdrawn outwardly from the outer peripheral surface of the substrate  70 . Then, the block  56  is lowered. This causes the grooved cam  36  to be lowered along with the block  56 .  FIGS. 4A and 4B  illustrate a state where the grooved cam  36  has been lowered. While the grooved cam  36  tries to rotate in the direction of the groove  38  during the lowering due to the reaction force from the rollers  16 , the stopper  23  prevents the rotation of the cam  36  by means of the engagement between the protrusions  40  and the cutouts  24 . Accordingly, on the contrary, the rollers  16  are moved in the clockwise direction while rotating within the groove  38  during the lowering of the grooved cam  36  and, along therewith, the transfer member  26  is rotated in the same direction. This causes the three rotation columns  10  to be concurrently rotated in the counter clockwise direction, thereby causing the three pins  20  to sandwich the outer peripheral surface of the substrate  70  ( FIG. 8 ( a )). As a result, the substrate  70  is held by the set of the three rotation columns  10  in such a manner as to maintain the center of the table  3  and that of the substrate  70  coincident with each other.  
         [0042]     At this state, the motor  9  is driven to cause the substrate  70  to rotate together with the rotation shaft  4  and the table  3 , while a cleaning liquid is ejected from the upper and lower nozzles. Consequently, the substrate  70  is cleaned substantially over its entire surface, except the portions thereof which is in contact with the pins  20 . During this time, the transfer members  26  and  27  and the grooved cams  36  and  37  are accompanied by the stopper  23  and rotated together with the rotation shaft  4 , and the respective rotation columns  10  and  11  are also revolved about the center shaft  5 .  
         [0043]     Next, the block  57  is lowered by means of the cylinder  52 . Then, during lowering the block  56 , the grooved cam  37  is lowered from the ascent position of  FIG. 1  in the same way of lowering the grooved cam  36 , and the transfer member  27  is rotated in the clockwise direction along with the rotation of the rollers  17 . This causes the rotation columns  11  being revolved to be rotated in the counter clockwise direction, thereby causing the three pins  21  to sandwich the outer peripheral surface of the substrate  70 . As a result, the substrate  70  is held by the sets of rotation columns each set being constituted by three rotation columns, namely a total of six rotation columns, without stopping the rotation of the substrate  70  ( FIG. 8 ( b )).  
         [0044]     Thereafter, the block  56  is lifted by means of the cylinder  51  along with the grooved cam  36 . This causes the transfer member  26  to be rotated in the counter clockwise direction, thereby causing the rotation columns  10  being revolved to be concurrently rotated in the clockwise direction. Consequently, the three pins  20  are separated from the substrate  70  ( FIG. 8 ( c )), thereby allowing its portions which have been contacted with the pins  20  to be cleaned.  
         [0045]     The cylinders  51  and  52  can be either push-type cylinders or pull type cylinders. In any of the cases, it is preferable to use return springs in combination therewith, in order to enable lowering the blocks  56  and  57  even in the event of stoppage of air supply due to a power failure, air leakage and the like. Further, while the numbers of the cylinders  51  and  52 , the protrusions  40  and  41  and the rollers  16  and  17  provided therein are all three, in order to reduce the bending moments to reduce the distortions generated in the grooved cams, the rollers and the transfer members, the numbers of them are not limited. The rotation columns  10  and  11  can have horizontal upper surfaces, but it is preferable that their upper surfaces are inclined. When their upper surfaces are inclined, the substrate  70  is supported by the rotation columns  10  and  11 , in a point-to-point contact. This allows the cleaning liquid to easily pass between the bottom surface of the substrate  70  and the rotation columns  10  and  11 , thereby increasing the cleaning ability. It is not necessary that the geometrical center of the table  3  is coincident with the rotation center thereof and, in the case where they are not coincident with each other, it is possible to clean the entire surface including the geometrical center more evenly. In order to make the geometrical center incoincident with the rotation center, one of the three rotation columns  10  (and  11 ) can be engaged with the transfer member  26  (and  27 ) such that it precedes or delays from the other two rotation columns by a tooth or two teeth.  
       Second Embodiment  
       [0046]      FIG. 9  is an axial cross-sectional view illustrating a substrate cleaning apparatus according to a second embodiment.  FIG. 10  is an enlarged view of the portion D in  FIG. 9 . The cleaning apparatus according to the present embodiment enables drying a substrate without moving the substrate, after cleaning. The cleaning apparatus  2  can have the same configuration as that of the first embodiment, under the table  3 . Hereinafter, there will be described, in detail, differences from the first embodiment and portions which were not described in the first embodiment.  
         [0047]     In the present embodiment, a cup-shaped cover  80  capable of housing the rotation columns  10  and  11  is provided on the upper surface of the table  3  such that it is hermetically contacted with the upper surface. The cover  80  can be hoisted and lowered by means of a hoisting apparatus which is not illustrated. Ring seals  88  made of a rubber or a fluororesin are fitted around the outer peripheral surfaces of the rotation columns  10  and  11 . O-ring seals  89  are similarly fitted around the outer peripheral surfaces of bolts with which the table  3  is fastened to the rotation shaft  4 . Further, as illustrated in  FIG. 10 , a ring seal  90  made of a fluororesin is fitted within an axial hole  30  in the table  3 . The ring seal  90  has a dual-lip shape having lips protruding upwardly and downwardly from the inner peripheral surface thereof. These lips are intimately contacted with the outer peripheral surface of the center shaft  5  and are curved in such directions that they are gradually separated from each other with decreasing distance from the center shaft  5 . Accordingly, during both pressurizing and depressurizing, it is possible to prevent air from passing therethrough. Further, the ring seal  90  is made of a fluororesin and, thus, has excellent chemical resistance and is less prone to generate dust. Thus, the hermeticity of the table  3  is maintained. Further, the table  3  extends to protrude from the rotation columns  10  and  11  outwardly in the radial direction. Further, when the cover  80  is lowered, the lower end surface of the cover  80  comes into contact with the upper surface of the protruding portion with a rubber O-ring seal  87  interposed therebetween. The O-ring seal  87  is fitted in an annular-shaped concave portion  74  formed in the lower end surface of the cover  80 . The cover  80  is provided with switching valves  82  and  85  and an exhaust valve  86 . Accordingly, when the cover  80  is lowered to be contacted with the table  3 , air is prevented from flowing into and from the space S surrounded by the cover  80  and the table  3 .  
         [0048]     It is also possible to ensure the hermeticity at the portion where the table  3  and the center shaft  5  are fitted with each other, by using two or more seals, such as a seal with an upper lip (for pressurization) and a seal with a lower lip (for depressurization), instead of using the ring seal  90 . As illustrated in a longitudinal cross-sectional view of  FIG. 13 , an annular concave portion  75  can be formed in the upper surface of a table  3 ′, instead of the concave portion  74 , and an O-ring seal  87  can be fitted therein to enable hermetically contacting the upper surface of the table  3 ′ with the lower end surface of the cover  80 ′. Further, the enlarged view of the portion D in  FIG. 13  is similar to  FIG. 10 .  
         [0049]     With the aforementioned cleaning apparatus  2 , after the rotation of the table  3  is stopped and the cover  80  is lowered to seal the periphery of the substrate  70  with the cover  80  and the table  3 , the pressure can be reduced with a vacuum pump  81  through the switching valve  82  for drying the substrate  70 . By alternating the sets of the rotation columns  10  and  11  which support the substrate  70 , it is possible to dry the portions contacted with the columns  10  and  11  without moving the substrate  70 . Since the depressurization increases the vaporization speed of the cleaning liquid, the substrate  70  is dried at a room temperature. Furthermore, the space S to be depressurized is a small area surrounded by the upper surface of the table  3  and the cover  80  and, therefore, can be rapidly depressurized. This can prevent occurrence of water marks. Furthermore, there is no need for moving the substrate  70  after cleaning, thereby preventing contaminations which would occur during moving. Also, it is possible to introduce, through the switching valve  85 , a gas inert to the substrate material and the conductive material, such as nitrogen, and concurrently exhaust air through the exhaust valve  86  while adjusting the pressure with a regulator  84 , prior to the depressurization before cleaning, as required. Further, depressurization and drying can be performed after or during the substitution of the nitrogen to fill the trenches with the nitrogen, thereby enabling cleanly drying without oxidizing the conductive material.