Patent Publication Number: US-2007107253-A1

Title: Substrate drying device and substrate processing method

Description:
BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The present invention relates to a substrate drying device and a substrate processing method.  
      2. Description of Related Art  
      Hitherto, there has been adopted a technique of spraying a dry gas from an air knife to a substrate to dry a substrate surface while transferring the substrate in one direction at the time of drying the substrate in a step of cleaning a glass substrate for a liquid crystal display or a semiconductor wafer in a manufacturing process of a liquid crystal display device or a semiconductor device. Such technique is disclosed in, for example, Japanese Unexamined Patent Application Publication No. 10-180205 and 8-288250.  
      Referring to  FIGS. 7 and 8 , a conventional air knife drying system is described.  FIG. 7  is a top view of the conventional air knife drying system, and  FIG. 8  is a sectional view taken long the line II-II′ of  FIG. 7 . As shown in  FIGS. 7 and 8 , an air knife  1  is provided above the surface of a substrate  2  to spray a dry gas in an arrow  11  direction while transferring the substrate  2  in an arrow  10  direction. As a result, rinse water  3  on the substrate  2  is blown off by the dry gas sprayed from the air knife  1 , and the substrate  2  surface can be dried.  
      Such drying system has a problem in that after the rinse water  3  is brown off, a water droplet  4  of the rinse water tends to remain at the end of the substrate  2  surface. As a solution to this problem, in the conventional system, the air knife  1  is placed at an angle  12  with respect to the transfer direction of the substrate  2 , or the air knife  1  is placed at an angle  13  to the substrate  2  surface, for example. Alternatively, these countermeasures are taken in combination.  
      If this problem cannot be overcome with the above method of placing the air knife at the angle  12  or  13 , the problem should be solved by increasing an air pressure of the dry gas sprayed from the air knife  1 . However, if the air is sprayed from the air knife  1  at a too high pressure, the rinse water  3  is evaporated in the form of mist  5  in some cases, the mist  5  readheres to the substrate  2  to cause a strain. Accordingly, there is a limitation on improvements in drying efficiency by increasing a pressure of the air sprayed from the air knife  1 .  
     SUMMARY OF THE INVENTION  
      The present invention has been made with a view to solving such problems, and it is accordingly an object of the invention to provide a substrate drying device capable of securely removing a water droplet remaining on a substrate without increasing an air pressure.  
      A substrate drying device according to an aspect of the invention includes: a nozzle ejecting a fluid to a substrate to be processed, wherein the substrate is moved relative to the nozzle while the nozzle is spraying the fluid to dry the substrate, a parallel component to a surface of the substrate in an ejection direction of the fluid is inclined with respect to a moving direction in which the substrate moves relative to the nozzle, and an angle between the parallel component and the moving direction is changed at a changed portion in a predetermined position of the nozzles. Thus, it is possible to provide a substrate drying device capable of securely removing a water droplet remaining on a substrate without increasing an air pressure.  
      Here, an arrangement direction of the nozzles may be bent at the changed portion to change an angle between the arrangement direction of the nozzles and the moving direction to change the component of the ejection direction parallel to the surface of the substrate and the moving direction.  
      Further, the arrangement direction of the nozzles may be bent at the changed portion. Thus, it is possible to suppress a decrease in air pressure due to the change in ejection direction.  
      Further, the changed portion may be formed in a plurality of positions. The changed portion may be formed substantially throughout the nozzles. Thus, the air pressure may be decreased more evenly due to the change in ejection direction.  
      Furthermore, preferably, the substrate has a substantially rectangular shape, and in a state where the changed portion is formed above the substrate, and the nozzle is arranged above a side as a downstream side of the substrate in the moving direction and an adjacent side of the side on the downstream side, the fluid is sprayed such that an angle between the parallel component to a surface of the substrate in the ejection direction of the fluid from the nozzle above the side on the downstream side and the side on the downstream side of the substrate is smaller than an angle between the parallel component to a surface of the substrate in the ejection direction of the fluid from the nozzle above the adjacent side and the side on the downstream side of the substrate.  
      According to another aspect of the invention, a substrate processing method for moving a substrate to be processed with respect to a nozzle ejecting a fluid to process the substrate, includes: processing the substrate with a liquid; and spraying a fluid to the substrate from the nozzle and moving the nozzle and the substrate relative to each other to dry the substrate; the spraying the fluid includes: setting an angle between a parallel component to a surface of the substrate in an ejection direction of the fluid and a moving direction of the substrate relative to the nozzle; and drying the substrate by spraying the fluid from nozzle with a changing portion which is formed in a predetermined position of the nozzle and in which the angle between a parallel component and the moving direction is changed. It is accordingly possible to securely remove a water droplet remaining on a substrate without increasing an air pressure.  
      According to the present invention, it is possible to provide a substrate drying device and a substrate processing method capable of securely removing a water droplet remaining on a substrate without increasing an air pressure.  
      The above and other objects, features and advantages of the present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus are not to be considered as limiting the present invention. BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a top view of a substrate drying system according to a first embodiment of the present invention;  
       FIG. 2  is a sectional view of the substrate drying system according to the first embodiment of the present invention;  
       FIG. 3  is a top view of a substrate to be processed according to the first embodiment of the present invention;  
       FIG. 4  is a top view of a substrate drying system according to another embodiment of the present invention;  
       FIG. 5  is a top view of a substrate drying system according to another embodiment of the present invention;  
       FIG. 6  is a top view of a substrate drying system according to another embodiment of the present invention;  
       FIG. 7  is a top view of a conventional substrate drying system; and  
       FIG. 8  is a sectional view of the conventional substrate drying system. 
    
    
     PREFERRED EMBODIMENT OF THE INVENTION  
     First Embodiment  
      Hereinafter, an embodiment of the present invention is described below with reference to the accompanying drawings. The embodiment of the present invention is accomplished such that in a substrate drying device having an air knife drying system, an angle at which an air is sprayed from an air knife is changed, by which a dry gas is sprayed as in parallel to the substrate side as possible at the substrate end portion to thereby improve a drying efficiency to prevent a water droplet from remaining without draining off.  
       FIG. 1  is a top view of an air knife drying system in a substrate drying device according to the embodiment of the present invention. A substrate  120  to be dried has substantially square shape as shown in  FIG. 1 . In  FIG. 1 , the lower side and right side of the substrate  120  are referred to as a lower side  120   a  and a right side  120   b . The substrate  120  is transferred with a transport roller or the like in a moving direction A as indicated by the arrow of  FIG. 1 . That is, the dashed line of  FIG. 1  indicates the moving direction A of the substrate  120 . Accordingly, the substrate  120  is fed from the left side to the right side in  FIG. 1 . The moving direction A of the substrate  120  is parallel to the lower side  120   a  of the substrate  120 . Thus, the moving direction A is orthogonal to the right side  120   b  continuous from the lower side  120   a  of the substrate  120 . Here, the right side  120   b  of the substrate  120  is positioned on the downstream side in the moving direction A of the substrate  120 . That is, a dry gas is first sprayed from an air knife to the right side  120   b  on the downstream side of the substrate  120  in the moving direction A. Incidentally, the lower side  120   a  is an adjacent side of the right side  120   b  positioned on the downstream side in the moving direction A of the substrate  120 .  
      An air knife  110  is placed on the substrate  120  surface. A dry gas is sprayed from an air nozzle of the air knife  110  in the direction of an arrow B in  FIG. 1 . The dry gas can blow off rinse water  130  applied to the substrate  120  surface. That is, while the air knife  110  is spraying the dry gas, the substrate  120  is transferred across an area where the air knife  110  sprays the dry gas. Hence, the dry gas is successively sprayed from the right end to the left end of the substrate  120 . Then, the rinse water on the substrate  120  surface is brown away, and the entire surface of the substrate  120  can be dried. The rinse water  130  is, for example, pure water. Incidentally, the air knife  110  may be provided on both of upper and lower surfaces of the substrate  120 .  
      The air knife  110  of this embodiment has a long and narrow shape as shown in  FIG. 1 , and is a bar-like or band-like member, for example. Slit-like opening is formed on the lower side of the air knife  110 . This opening is air nozzle  112 . The air nozzle  112  is arranged along the direction in which the air knife extends. The air nozzle  112  is formed over a longitudinal direction of the air knife  110 . The dry gas is sprayed from the air nozzle  112  in the direction of the arrow B of  FIG. 1 . The air pressure is, for example, 0.8 MPa, but the air pressure may be 0.8 MPa or higher, or 0.8 MPa or lower. The air pressured needs to be high enough to blow off the rinse water  130 , and is desirably set to such a pressure as can prevent the rinse water  130  from evaporating as mist. The dry gas is an air or an inert gas such as nitrogen gas.  
       FIG. 2  is a sectional view taken along the line I-I′ of  FIG. 1 . The air knife  110  is placed such that the air ejection direction as indicated by the arrow B of  FIG. 2  is inclined at the angle M to the substrate  120  surface. The angle M is preferably as small as possible since the use efficiency and the drying efficiency of the dry gas can be improved.  
      As shown  FIG. 1 , the air knife  110  has a bending portion  111  as a changed portion around the center. The air knife  110  is bended by the angle G at the bending portion  111 . Accordingly, the air knife  110  takes a dog-leg shape. The air nozzle  112  is arranged along the dog-leg shape of the air knife  110 . Thus, the angle of the air nozzle  112  to the moving direction A of the substrate  120  is changed. The air nozzle  112  is provided in a dog-leg shape. The bending angle of the air nozzle  112  at the bending portion  111  is angle G. Here, a part of the nozzle  112  from the left end of the air knife  110  to the bending portion  111  are referred to as air nozzle  112   a , and a part of the nozzle  112  from the right end of the air knife to the bending portion  111  are referred to as air nozzle  112   b . The air nozzle  112   a  and the air nozzle  112   b  form an angle G therebetween. In other words, the air nozzle  112   a  and the air nozzle  112   b  that are inclined with each other cross at the bending portion  111 .  
      In the plane parallel to the substrate surface, the ejection direction B of the dry gas from the air nozzle  112  is vertical to the arrangement direction of the air nozzle  112 . Thus, a component of the dry gas ejection direction B parallel to the substrate surface is changed at the bending portion  111 . Accordingly, an angle between the component of the dry gas ejection direction B parallel to the substrate surface and the moving direction A is changed at the midpoint of the air nozzle  112  (bending portion  111 ). That is, the ejection direction B of the air nozzle  112   a  and the ejection direction B of the air nozzle  112   b  form the angle G. The bending portion  111  may be set in an arbitrary position of the air nozzle  112 .  
      Here, provided that an area where the air nozzle  112  sprays the dry gas is an ejection area, the ejection area shape corresponds to the shape of the air nozzle  112 . Accordingly, the ejection area on the substrate  120  surface, that is, a dry gas spraying area has a dog-leg shape similarly to the shape of the air nozzle  112 . The substrate  120  crosses the ejection area to thereby execute the drying process of the substrate  120 . The ejection area is formed throughout entire substrate in the direction parallel to the short side of the substrate  120 , that is, in the direction vertical to the moving direction A as substrate transferring direction. In other words, the ejection area is set to have the length larger than the substrate  120  width, that is, the length of the right side  120   b  if projected in the direction vertical to the substrate surface, that is, to the plane parallel to the substrate  120 .  
      As shown in  FIG. 1 , the air nozzle  112   a  of the air knife  110  is arranged at the angle C to the moving direction A of the substrate  120 . The air nozzle  112   b  of the air knife  110  is arranged at the angle D to the moving direction A of the substrate  120 . Incidentally, the angle C and the angle D as the angle between the moving direction A and the arrangement direction of the air nozzle  112  are 90° or smaller. Here, the angle G of the bending portion  111  is set such that the angle D is smaller than the angle C. As a result, the dry gas ejection direction B at ends  121  and  122  of the substrate  120  can be closer to the side of the substrate  120 . That is, an angle F between the lower side  120   a  of the substrate  120  and the ejection direction B of the dry gas from the air nozzle  112   a  above the lower side  120   a  can be made smaller, and an angle E between the right side  120   b  of the substrate and the ejection direction B of the dry gas from the air nozzle  112   b  above the right side  120   b  can be made smaller. If an angle between the ejection direction B of the dry gas from the air nozzle  112   a  and the right side  120   b  is an angle N, the bending portion  111  is provided, so the angle E is smaller than the angle N.  
      Detailed description thereof is described below. In the plane parallel to the substrate surface, the air knife  110  is inclined with respect to the moving direction A of the substrate  120 . Accordingly, the air nozzle  112   a  is provided on the upstream side of the air nozzle  112   b  in the moving direction A of the substrate  120 . The air nozzle  112   a  out of the air nozzle  112  is arranged on the upstream side in the moving direction A of the substrate  120 , and the air nozzle  112   b  is arranged on the downstream side in the moving direction A of the substrate. The bending portion  111  is formed, so an angle between the arrangement direction of the air nozzle  112  and the moving direction A of the substrate  120  is different between the upstream side and the downstream side of the bending portion  111 . As shown in  FIG. 1 , the angle of the upstream side, that is, the angle between the air nozzle  112   a  and the moving direction A is the angle C. The angle of the downstream side, that is, the angle between the air nozzle  112   b  and the moving direction A is the angle D. Here, a difference between the angle C and the angle D corresponds to the angle G.  
      The moving direction A is parallel to the lower side  120   a  of the substrate  120 , so the angle between the lower side  120   a  of the substrate  120  and the air nozzle  112   a  is the angle C. Further, the angle between the lower side  120   a  of the substrate  120  and the air nozzle  112   b  is the angle D.  
      Consider such a state that the air nozzle  112   a  is arranged above the lower side  120   a  of the substrate  120 , and the air nozzle  112   b  is arranged above the right side  120   b  continuous from the lower side  120   a  of the substrate  120  as shown in  FIG. 1 . That is, consider such a state that the air nozzle  112   a  is arranged across the lower side  120   a , and the air nozzle  112   b  is arranged across the right side  120   b  as the downstream side. In this state, the bending portion  111  is positioned above the substrate  120 .  
      An angle between the lower side  120   a  of the substrate  120  and the air nozzle  112   a  above the lower side  120   a  of the substrate  120  is an angle C. An angle between the lower side  120   a  with the air nozzle  112   a  and the air nozzle  112   b  arranged above the right side  120   b  is an angle D. Here, the angle G is set such that the angle C is smaller than the angle D. Thus, an angle F between the lower side  120   a  of the substrate  120  and the ejection direction B of the air nozzle  112   a  above the lower side  120   a  can be made smaller. As a result, at the substrate end  122  near the lower side  120   a , the component of the ejection direction B parallel to the substrate surface can get close to parallel to the lower side  120   a . Further, the angle E between the right side  120   b  of the substrate  120  and the ejection direction B of the air nozzle  112   b  above the right side  120   b  can be made smaller. Thus, at the substrate end  121  near the right side  120   b , the component of the ejection direction B parallel to the substrate surface can get close to parallel to the right side  120   b.    
      In the present invention, the bending portion  111  for changing the component of the ejection direction B parallel to the substrate surface is provided at the midpoint of the air nozzle  112 . Thus, a dry gas ejection direction adequate for not only the right side  120   b  as the downstream side of the substrate  120  but also the lower side  120   a  continuous from the right side  120   b  can be realized. Accordingly, it is possible to reliably dry the substrate  120 . In this way, the ejection direction at the substrate end gets close to parallel to the substrate side, by which the rinse water  130  at the substrate end can be efficiently dried.  
      The reason why the ejection direction B at the substrate ends  121  and  122  gets close to parallel to the sides  120   a  and  120   b  to thereby efficiency dry the rinse water  130  is described in brief. In some cases, in a step of rinsing the substrate  120  with the rinse water  130 , the rinse water  130  cannot sufficiently the substrate ends  121  and  122 . In this case, as shown in  FIG. 3 , the substrate ends  121  and  122  are exposed portion  123  not covered with the rinse water  130 . That is, the exposed portion  123  is dried and exposed to the atmosphere. Therefore, the exposed portion  123  is highly hydrophilic. As a result, the substrate ends  121  and 122  are hardly dried with the air knife  110 , and water droplets tend to remain there.  
      Further, on the downstream side of the substrate  120 , the rinse water  130  near the right side  120   b  is moved from the right side  120   b  to the substrate center by spraying the dry gas. That is, the dry gas is sprayed from the outer side to the inner side of the substrate  120  near the right side  120   b  on the downstream side in the moving direction A of the substrate  120 . Then, the substrate end  121  is highly hydrophilic for the above reason, so the substrate end near the right side  120   b  is more difficult to dry.  
      Moreover, also at the substrate end  122 , the dry gas is sprayed from the air nozzle  112   a  from the outer side to the inner side of the substrate  120 . Thus, as in the portion around the right side  120   b , the substrate end  122  is difficult to dry. That is, the substrate ends  122  and  121  around the lower side  120   a  and the right side  120   b  are less dried than the substrate ends around the upper side and the left side.  
      In the present invention, the bending portion  111  is formed, by which the component of the ejection direction B of the air nozzle  112   b  parallel to the substrate surface gets close to parallel to the right side  120   b . That is, the angle E is decreased. Hence, the rinse water  130  left around the substrate end  121  is moved along the right side  120   b  of the substrate  120 . Accordingly, it is possible to prevent the rinse water from moving to the substrate center from the substrate end  121 , and the substrate can be surely dried. Furthermore, the component of the ejection direction B of the air nozzle  112   a  parallel to the substrate surface gets close to parallel to the lower side  120   a . That is, the angle F is decreased. Thus, the rinse water  130  remaining around the substrate end  122  is moved along the lower side  120   a  of the substrate  120 . Accordingly, it is possible to prevent the rinse water  130  from moving from the substrate end  122  to the substrate center, and the substrate  120  can be surely dried. Thus, the substrate ends  121  and  122  where water droplets tend to remain can be efficiently dried.  
      Further, in the state as shown in  FIG. 1 , the angle D between the air nozzle  112   b  and the lower side  120   a  is smaller than  450 . Hence, the dry gas can be sprayed at the angle E that makes the ejection direction parallel to the right side  120   b . Further, the angle C between the air nozzle  112   a  and the lower side  120   a  is made larger than  450 . As a result, the dry gas can be sprayed at the angle F that is close to parallel to the lower side  120   a . The direction of the air nozzle  112  is changed in this way, so the dry gas ejection direction B around a corner portion where the lower side  120   a  crosses the right side  120   b  can get close to parallel to the lower side  120   a . That is, the ejection direction B at the substrate end  121  near the lower side  120   a  of the substrate  120  can get close to parallel to the lower side  120   a.    
      The air knife  110  is arranged/formed such that the angle D on the downstream side is smaller than the angle C on the upstream side, by which the angle E between the dry gas ejection direction B of the substrate  120  and the lower side  120   a  of the substrate  120 , and the angle F between the dry gas ejection direction B of the substrate  120  and the right side  120   b  can be decreased. Thus, the dry gas ejection angles at the substrate ends  121  and  122  are set to be close to parallel to the substrate side. Incidentally, the angle C preferably ranges from 45° to 60°.  
      Here, if the angle G of the bending portion  111  is too large, the angle D is too small. For example, if the angle D is 0°, the air knife  110  cannot pass through the entire substrate end  121 . The air knife  110  passes through only the substrate end  121  from the substrate end  122  side to the bending portion. In this case, the dry gas is not sufficiently sprayed in some portions of the substrate  120  surface. This is undesirable. Accordingly, as shown in  FIG. 1 , when the air nozzle  112   a  on the upstream side is moved above the lower side  120   a  of the substrate  120 , the air nozzle  112  is gradually closer to the upper side opposite to the lower side  120   a  of the substrate, from the upstream side to the downstream side. That is, the angle G is set such that the air nozzle  112  formed on the right side (downstream side) is positioned on the upper side.  
      Further, if the angle G is too large, the angle of the ejection direction B is abruptly changed around the bending portion  111 , and the air ejection pressure in the direction of an arrow H of  FIG. 1  is lowered. In this case, the rinse water  130  cannot be sufficiently drained off at the bending portion  111 . Thus, the angle G of the bending portion  111  is determined based on the relation between the angle C and the angle D, and is preferably 15° to 60°.  
      In this structure, the substrate  120  is transferred in the moving direction A of  FIG. 1  while the air knife  110  is spraying the dry gas to the substrate  120  surface in the arrow B direction. Furthermore, a parallel component to the surface of the substrate  120  in the dry gas ejection direction B is inclined with respect to a moving direction A. The angle between the parallel component and the moving direction A is changed at the changed portion in the predetermined position of the nozzle  110 . As a result, the rinse water  130  on the substrate  120  surface can be removed.  
      With the above structure, a drying process can be executed without increasing a dry gas pressure, and it is possible to suppress a splash of the rinse water  130  due to the application of the dry gas and suppress the generation of mist. Further, a consumed amount of dry gas can be reduced, and a running cost of the drying step can be saved. Accordingly, the substrate  120  can be efficiently dried.  
      As described above, according to the first embodiment of the present invention, it is possible to a substrate drying device and a substrate drying method that can preferably remove water droplets remaining on the substrate without increasing an air pressure.  
      Incidentally, in the above description, an example of spraying a gas from the air knife  110  is demonstrated, but it is possible to spray a volatile liquid, for example, to blow off the rinse water  130 . That is, a liquid and such other fluid may be used for drying the substrate  120  in place of the gas. Further, the pure water is used as the rinse water  130  in the above description, but the rinse water may be, for example, an etchant, a washing solution, a chemical solution, and other such liquids. The substrate moving direction is not limited to a direction parallel to the substrate side but may be inclined to the substrate side. Moreover, the air knife, not the substrate, may be moved.  
     Second Embodiment  
      Referring to  FIG. 4 , a second embodiment of the present invention is described. Hence explanations of portions similar to first embodiment are omitted. The air knife  110  of  FIG. 4  is curved with a predetermined radius of curvature in the bending portion  111 . Further, the air knife  110  is curved over the angle J in the bending portion  111 . Accordingly, the angle of the air nozzle  112  can be changed. Thus, a component of the ejection direction B parallel to the substrate surface is changed to decrease the angles E and F at the substrate ends  121  and  122 .  
      In the embodiment of  FIG. 4 , air nozzle  112   j  in the bending portion  111  is curved over the angle J. That is, instead of changing the angle at one point as shown in  FIG. 1 , the angle of the air knife  110  is changed in the range of the angle J as shown in  FIG. 4 . Thus, a decrease of the dry gas ejection pressure in the direction of an arrow H of  FIG. 1  can be dispersed evenly over the angle J. Thus, it is possible to suppress a decrease in air ejection pressure in the bending portion  111 . The angle J is set such that the angle D is smaller than the angle C in  FIG. 4 .  
     Third Embodiment  
      Referring to  FIG. 5 , a third embodiment of the present invention is described. Hence explanations of portions similar to first embodiment are omitted. The air knife  110  of  FIG. 5  changes its angle at two positions, bending portions  113  and  114 . That is, air nozzle  112   c  is arranged between the upstream-side air nozzle  112   a  and the downstream-side air nozzle  112   b . Here, provided that an angle between the air nozzle  112   c  and the moving direction A is K, the relation among the angles C, K, and D is C&gt;K&gt;D. That is, the air nozzle  112  is gradually closer to the upper side opposite to the lower side  120   a  of the substrate, from the upstream side to the downstream side. The air knife  110  of  FIG. 5  changes its angle at two positions, bending portions  113  and  114 , not at one position as shown in  FIG. 1 . Thus, the dry gas ejection direction B is changed at two positions, the bending portions  113  and  114 , and the decrease in air ejection pressure at the bending portions can be suppressed.  
      A feature of this embodiment is to change the angle of the air knife  110  at plural positions. The number of positions is not limited to two as shown in  FIG. 5 , but may be three or more. Thus, the angle of the air knife  110  is changed more largely than the case of changing the angle at one position. Further, the angles E and F can be more decreased. Further, plural bent (curved) portions  111  as shown in  FIG. 4  may be formed as changed portions. Alternatively, the bent portions and the curved portions may be both formed.  
     Fourth Embodiment  
      Referring to  FIG. 6 , a fourth embodiment of the present invention is described. Hence explanations of portions similar to first embodiment are omitted. The whole air knife  110  of  FIG. 6  is curved with a predetermined radius of curvature over the angle L. The whole air knife  110  is changed instead of changing the angle only in the bending portion  111  as shown in  FIG. 4 . Thus, the air ejection direction B is changed evenly throughout the air knife  110  in accordance with the curved form, and the decrease in air ejection pressure can be suppressed. The angle L is, for example, 90°. With this structure, the dry air ejection direction B can be made substantially parallel to the substrate sides at the substrate ends  121  and  122 .  
      As shown in  FIG. 6 , the end portion of the air nozzle  112  on the upper side of the substrate  120  is positioned at the substrate end. As a result, the dry gas can be sprayed to the end portions around the upper side of the substrate as well. Further, it is possible to spray the dry gas from the inner side to the outer side of the substrate, around the upper side of the substrate. Hence, moisture around the upper side of the substrate  120  can be efficiently dried.  
      Incidentally, in the modes described in the above embodiments, the air knife is provided with the bending portions to change the dry gas ejection direction. However, instead of changing the air knife itself, the ejection direction of the air nozzle of the air knife is changed to thereby obtain beneficial effects similar to the above embodiments. Further, this is effective for the drying step in a manufacturing process of a semiconductor or liquid crystal display device. Further, the present invention is applicable to removal of liquids such as an etchant as well as the rinse water.  
      From the invention thus described, it will be obvious that the embodiments of the invention may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended for inclusion within the scope of the following claims.