Processing cup and substrate processing apparatus

A substrate is surrounded by an inner cup and an outer cup. A distance between an upper surface of an inner cup lower portion and a lower surface of an inner cup upper portion of the inner cup is gradually reduced outward from an outer periphery of the substrate. A clearance is formed between the upper surface of the inner cup lower portion and the lower surface of the inner cup upper portion at outer peripheries of the inner cup lower portion and the inner cup upper portion. A collection space is formed between the upper surface of the inner cup lower portion and the lower surface of the inner cup upper portion. A scatter capturing space that allows a processing liquid that has passed through the clearance to scatter and captures the scattering processing liquid is formed by an outer cup. An upper portion and an outer periphery of the scatter capturing space are covered by a lower surface and an inner side surface of the outer cup, respectively. The processing liquid that has passed through the clearance is led to the inner side surface by the lower surface of the outer cup.

BACKGROUND OF THE INVENTION

(1) Field of the Invention

The present invention relates to a processing cup and a substrate processing apparatus including the processing cup.

(2) Description of Related Art

Rotary substrate processing apparatuses have been used to subject semiconductor wafers and substrates such as glass substrates for liquid crystal display devices, glass substrates for photomasks, and glass substrates for optical disks to processing using processing liquids such as development liquids, cleaning liquids, rinse liquids, or photoresist liquids.

In the rotary substrate processing apparatuses, spin holders horizontally support the substrates. The spin holders rotate the substrates while the processing liquids are dropped on the centers of upper surfaces of the substrates. Thus, the substrates are processed using the processing liquids. In such a substrate processing apparatus, a processing cup surrounds a spin holder to prevent part of a processing liquid from splashing to the vicinity of the substrate by a centrifugal force developed when the substrate is rotated (e.g., JP 2002-361155 A, JP 2007-287998 A, JP 2007-311775 A, JP 2009-38083 A and JP 2012-19025 A).

BRIEF SUMMARY OF THE INVENTION

In each substrate processing apparatus described in JP 2002-361155 A, JP 2007-287998 A, JP 2007-311775 A, JP 2009-38083 A and JP 2012-19025 A, the processing liquid that has splashed to the vicinity of the substrate may adhere to the substrate again by catching a returning air flow. For example, in a liquid processing apparatus described in JP 2007-287998 A, a gas collector is provided in the vicinity of the substrate such that such a returning air flow is trapped. It is described that this causes a re-adherence of the processing liquid that has splashed to the vicinity of the substrate to the substrate to be suppressed. However, the processing liquid that has splashed to the vicinity of the substrate cannot be reliably prevented from adhering to the substrate again.

An object of the present invention is to provide a processing cup and a substrate processing apparatus that can reliably prevent a processing liquid that has splashed outward from a substrate from adhering to the substrate again.

(1) According to an aspect of the present invention, a processing cup provided to surround a substrate when processing using a processing liquid is performed on the substrate held in a substantially horizontal attitude includes a first cup arranged to surround the substrate, and a second cup arranged to surround the first cup, wherein the first cup includes a first member having a first upper surface arranged to surround the substrate and a second member having a first lower surface arranged above the first upper surface of the first member to surround the substrate, the first and second members are configured such that a distance between the first upper surface and the first lower surface is gradually reduced outward from an outer periphery of the substrate and a clearance is formed between the first upper surface and the first lower surface at outer peripheries of the first and second members, a first collection space that collects a processing liquid is formed between the first upper surface and the first lower surface, and the second cup is configured to form a scatter capturing space that allows the scattering of the processing liquid that has passed through the clearance and captures the scattering processing liquid, and has a second lower surface covering an upper portion of the scatter capturing space and an inner side surface covering an outer periphery of the scatter capturing space, the second lower surface being formed to lead the processing liquid that has passed through the clearance to the inner side surface.

In this processing cup, the first and second members are arranged to surround the substrate. The distance between the first upper surface of the first member and the first lower surface of the second member is gradually reduced outward from the outer periphery of the substrate. The clearance is formed between the first upper surface and the first lower surface at the outer peripheries of the first and second members.

In this case, the distance between the first upper surface and the first lower surface is the largest at a position that is the closest to the substrate. Therefore, the processing liquid that has splashed outward from the substrate is collected in the first collection space formed between the first upper surface and the first lower surface. The collected processing liquid is led outward along the first upper surface and the first lower surface, thereby being gathered in the clearance at the outer peripheries and passing through the clearance.

The second cup is arranged to surround the first and the second members. The scatter capturing space is formed by the second cup. The upper portion and the outer periphery of the scatter capturing space are covered by the second lower surface and the inner side surface of the second cup, respectively. The processing liquid that has passed through the clearance of the first cup is captured at the inner side surface of the second cup after scattering in the scatter capturing space in the second cup. Further, part of the processing liquid that has passed through the clearance is led to the inner side surface of the second cup by the second lower surface.

This configuration causes the processing liquid that has once passed outward through the clearance of the first cup to be sufficiently captured in the scatter capturing space in the second cup, thereby not passing through the clearance again to return to the first collection space. As a result, the processing liquid that has splashed outward from the substrate can be reliably prevented from adhering to the substrate again.

(2) A second collection space that collects the processing liquid may be formed below the first member.

The processing liquid that splashes from the substrate may splash to below the first member. Even in this case, the processing liquid that has splashed to below the first member is collected in the second collection space. Thus, the processing liquid that has splashed outward from the substrate can be reliably prevented from adhering to the substrate again.

(3) The second cup may be configured to further form an acquisition space that acquires the processing liquid on a peripheral edge of the scatter capturing space.

Even if the processing liquid that has collided with the inner side surface of the second cup spreads upward or floats up, the processing liquid is acquired in the acquisition space. Thus, a sufficient amount of the processing liquid can be captured or acquired in the scatter capturing space and the acquisition space in the second cup.

(4) The first upper surface of the first member, the first lower surface of the second member and the clearance may be shaped to be rotationally-symmetric about a common axis.

In this case, the processing cup can be provided at the rotary substrate processing apparatus. When the processing using the processing liquid is performed on the substrate while the substrate is rotated, the processing liquid that has splashed in an every direction from the substrate can be reliably collected in the first collection space. Further, the processing liquid that has been collected in the first collection space and has passed through the clearance can be reliably captured in the scatter capturing space.

(5) The scatter capturing space may be shaped to be non-circular about the common axis. In this case, the scatter capturing space can be made larger than the circular scatter capturing space without increasing a size of the processing cup as a whole. Thus, even if processing using a large amount of the processing liquid is performed in the processing cup, the processing liquid that has splashed outward from the substrate can be reliably prevented from adhering to the substrate again.

(6) The scatter capturing space may be shaped to be rectangular in a cross section vertical to the common axis.

In this case, a capacity at four corners of the scatter capturing space increases. Thus, the scatter capturing space can be reliably made larger than the circular scatter capturing space without increasing the size of the processing cup as a whole. Therefore, even if the processing using a large amount of the processing liquid is performed in the processing cup, the processing liquid that has splashed outward from the substrate can be reliably prevented from adhering to the substrate again.

(7) The first upper surface of the first member may be formed to be inclined outward upward at a first angle with respect to an upper surface of the substrate. In this case, the processing liquid that has splashed outward from the substrate can be easily collected in the first collection space.

(8) The first angle may be not less than 5 degrees and not more than 20 degrees. In this case, the processing liquid that has splashed outward from the substrate can reliably pass through the clearance between the first upper surface of the first member and the first lower surface of the second member, and the processing liquid that has hit the first upper surface of the first member can be reliably prevented from rebounding on the substrate.

(9) The first lower surface of the second member may be formed to extend outward in parallel with an upper surface of the substrate or to be inclined downward at a second angle with respect to the upper surface of the substrate.

In this case, the processing liquid adhering to the first lower surface of the second member is led to the first collection space via the first lower surface by outward splashing force or gravity. Thus, the processing liquid that has splashed outward from the substrate can be easily collected in the first collection space.

(10) The second angle may be more than 0 degree and not more than 20 degrees. In this case, the processing liquid that has splashed outward from the substrate can reliably pass through the clearance between the first upper surface of the first member and the first lower surface of the second member, and the processing liquid that has hit the first lower surface of the second member can be reliably prevented from rebounding on the substrate.

(11) The second lower surface may be formed to extend outward in parallel with an upper surface of the substrate or to be inclined downward at a third angle with respect to the upper surface of the substrate.

In this case, the processing liquid that has passed through the clearance and has adhered to the second lower surface is led to the inner side surface via the second lower surface by the outward splashing force or gravity. Thus, the processing liquid that has passed through the clearance can be reliably captured in the scatter capturing space.

(12) The third angle may be more than 0 degree and not more than 20 degrees. In this case, the processing liquid that has passed through the clearance and has hit the second lower surface can be reliably prevented from rebounding to the first collection space.

(13) A maximal length of the scatter capturing space may be larger than a maximal length of the first collection space in a radial direction of the substrate.

In this case, a large amount of the processing liquid can be captured in the scatter capturing space. Therefore, even if a large amount of the processing liquid has passed through the clearance of the first cup, the processing liquid that has rebounded on the inner side surface of the second cup in a direction toward the first collection space can be reliably prevented from passing through the clearance again to return to the first collection space.

(14) The second cup may further have a second upper surface covering a lower portion of the scatter capturing space, a distance between the second lower surface and the second upper surface being gradually reduced outward from outer peripheries of the first lower surface and the first upper surface.

In this case, the processing liquid that has passed through the clearance of the first cup is reliably led to the inner side surface of the second cup by the second upper surface and the second lower surface. Thus, the processing liquid that has splashed outward from the substrate can be reliably prevented from adhering to the substrate again.

(15) The processing cup may further include a drain port that leads the processing liquid in the scatter capturing space to a drain system. In this case, the processing liquid that has been captured in the scatter capturing space can be reliably drained.

(16) According to another aspect of the present invention, a substrate processing apparatus that performs processing on a substrate includes a spin holder that rotates the substrate while holding the same in a substantially horizontal attitude, a first processing liquid supply system that supplies a processing liquid to a first surface of the substrate held by the spin holder, and the processing cup described above provided to surround the substrate held by the spin holder.

In this substrate processing apparatus, the substrate is held in a horizontal attitude and rotated by the spin holder. Further, the processing liquid is supplied to the first surface of the substrate by the first processing liquid supply system. The processing liquid that has splashed outward from the first surface of the substrate by the centrifugal force developed by the rotation of the substrate is collected in the first collection space formed between the first upper surface and the first lower surface. The collected processing liquid is led outward along the first upper surface and the first lower surface, thereby being gathered in the clearance at the outer peripheries and passing through the clearance.

The processing liquid that has passed through the clearance of the first cup is captured at the inner side surface of the second cup after scattering in the scatter capturing space in the second cup. Further, part of the processing liquid that has passed through the clearance is led to the inner side surface of the second cup by the second lower surface.

This configuration causes the processing liquid that has once passed outward through the clearance of the first cup to be sufficiently captured in the scatter capturing space in the second cup, thereby not passing through the clearance again to return to the first collection space. As a result, the processing liquid that has splashed outward from the substrate can be reliably prevented from adhering to the substrate again.

(17) The substrate processing apparatus may further include a second processing liquid supply system that supplies a processing liquid on a second surface that is opposite to the first surface of the substrate held by the spin holder, and a processing gas supply system that supplies a processing gas to the second surface of the substrate held by the spin holder.

In this case, outward force generated by the processing gas supplied to the second surface of the substrate by the processing gas supply system is added to the processing liquid that has been supplied to the second surface of the substrate by the second processing liquid supply system. The outward force is added to the centrifugal force developed by the rotation of the substrate, so that the processing liquid that has splashed outward from the second surface of the substrate is reliably captured in the scatter capturing space in the second cup. As a result, the processing liquid that has splashed outward from the substrate can be reliably prevented from adhering to the substrate again.

Other features, elements, characteristics, and advantages of the present invention will become more apparent from the following description of preferred embodiments of the present invention with reference to the attached drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

A rotary substrate processing apparatus including a processing cup according to an embodiment of the present invention will be described below with reference to the drawings.FIGS. 1 and 2are schematic cross sectional views of the rotary substrate processing apparatus including the processing cup according to the one embodiment of the present invention taken along one direction.FIG. 3is a schematic cross sectional view of the rotary substrate processing apparatus including the processing cup according to the one embodiment of the present invention taken along another direction.FIG. 4is a plan view of the rotary substrate processing apparatus ofFIGS. 1 to 3.FIG. 5is an enlarged cross sectional view of a section A of the processing cup ofFIG. 1. Note thatFIGS. 1 and 2are cross sectional views taken along the line B-B ofFIG. 4, andFIG. 3is a cross sectional view taken along the line C-C ofFIG. 4.

As shown inFIGS. 1 to 3, the substrate processing apparatus100has a spin holder1that holds a substrate W in a horizontal attitude while rotating the same. The spin holder1is attached to a tip end of a rotation shaft2of a motor3and is driven to rotate around a vertical axis.

An inner cup4for splash guarding is provided to surround the substrate W held by the spin holder1. An outer cup5for splash guarding and a cup support member13are provided to surround the inner cup4. The inner cup4, the outer cup5and the cup support member13are shaped to be rotationally-symmetric with respect to the rotation shaft2. This enables the inner cup4and the outer cup5to be provided at the rotary substrate processing apparatus100. The inner cup4and the outer cup5are provided not to be rotated around the rotation shaft2. A processing cup C is constituted by the inner cup4and the outer cup5.

The outer cup5is supported by the cup support member13. A cylinder10is connected to the inner cup4with a support frame11sandwiched therebetween. The inner cup4can be moved in a vertical direction by the operation of this cylinder10. As shown inFIG. 2, the upper end of the inner cup4can be moved to a position lower than the substrate W. Hereinafter, as shown inFIG. 1, a state where the inner cup4is moved to the highest position is referred to as a lifted state. As shown inFIG. 2, a state where the inner cup4is moved to the lowest position is referred to as a lowered state.

The inner cup4is constituted by an inner cup lower portion41and an inner cup upper portion42. Outer edges of the inner cup lower portion41and the inner cup upper portion42are shaped to be substantially circular in a cross section vertical to the rotation shaft2(hereinafter referred to as a horizontal cross section), and inner edges of the inner cup lower portion41and the inner cup upper portion42are shaped to be substantially circular in the horizontal cross section. That is, the inner cup lower portion41and the inner cup upper portion42are shaped to be substantially annular in the horizontal cross section. A circular opening42bis formed at the center of the inner cup upper portion42.

The inner cup lower portion41is arranged to surround a space below the substrate W in the lifted state. As shown inFIG. 2, when the inner cup4is in the lowered state, the substrate W is positioned above the opening42bof the inner cup upper portion42. The inner cup lower portion41has an upper surface41aand a side surface41b. The side surface41bis formed to extend downward from an outer edge of the upper surface41a.

The inner cup upper portion42is arranged to surround a space above the substrate W and to be positioned above the inner cup lower portion41. The inner cup upper portion42has a lower surface42a.

As shown inFIG. 5, the upper surface41aof the inner cup lower portion41is inclined obliquely upward toward an outer periphery. An inclination angle of the upper surface41aof the inner cup lower portion41with respect to a horizontal plane is θ1. In the present embodiment, the inclination angle θ1is not less than 5 degrees and not more than 20 degrees, for example. The lower surface42aof the inner cup upper portion42is inclined obliquely downward toward an outer periphery. The inclination angle of the lower surface42aof the inner cup upper portion42with respect to the horizontal plane is θ2. In the present embodiment, the inclination angle θ2is more than 0 degree and not more than 20 degrees, for example.

A space V1is formed between the upper surface41aof the inner cup lower portion41and the lower surface42aof the inner cup upper portion42. Further, a space V2is formed below the inner cup lower portion41. Hereinafter, the spaces V1, V2are referred to as collection spaces V1, V2.

A distance between the upper surface41aof the inner cup lower portion41and the lower surface42aof the inner cup upper portion42is gradually reduced outward from an outer periphery of the substrate W. A clearance S is formed between the upper surface41aof the inner cup lower portion41and the lower surface42aof the inner cup upper portion42at the outer peripheries of the upper surface41aof the inner cup lower portion41and the lower surface42aof the inner cup upper portion42. The inner cup lower portion41and the inner cup upper portion42may be configured to be independently movable in the vertical direction, respectively. In this case, a length of the clearance S in the vertical direction can be adjusted. The length of the clearance S in the vertical direction is from 1 mm to 5 mm, for example, and 2 mm in the present embodiment.

As shown inFIGS. 1 to 3, the outer cup5is constituted by an outer cup upper portion51, an outer cup side portion52, an outer cup intermediate portion53and an outer cup lower portion54. Outer edges of the outer cup upper portion51, the outer cup side portion52and the outer cup intermediate portion53are shaped to be substantially rectangular in the horizontal cross section, and inner edges of the outer cup upper portion51, the outer cup side portion52and the outer cup intermediate portion53are shaped to be substantially circular in the horizontal cross section. Outer and inner edges of the outer cup lower portion54are shaped to be substantially circular in the horizontal cross section. That is, the outer cup lower portion54is shaped to be substantially annular in the horizontal cross section. A circular opening51d(SeeFIG. 2) is formed at the center of the outer cup upper portion51. When the inner cup4is in the lifted state, the inner cup upper portion42is fitted into the opening51dof the outer cup upper portion51.

The outer cup upper portion51is arranged to surround the inner cup lower portion41and the inner cup upper portion42. The outer cup upper portion51has a lower surface51a. As shown inFIG. 5, the lower surface51aof the outer cup upper portion51is inclined obliquely downward toward an outer periphery. The inclination angle of the lower surface51aof the outer cup upper portion51with respect to the horizontal plane is θ3. In the present embodiment, the inclination angle θ3is more than 0 degree and not more than 20 degrees, for example.

A groove51bis formed at the outer edge of the outer cup upper portion51such that a space V4is formed on a peripheral edge of a space V3described below. Hereinafter, the space V4is referred to as the acquisition space V4. An upper engaging portion51c(seeFIG. 2) for engaging the inner cup upper portion42when the inner cup4is in the lifted state is formed at the inner edge of the outer cup upper portion51.

The outer cup intermediate portion53is arranged to surround the inner cup lower portion41or the inner cup upper portion42at a position lower than the substrate W. The outer cup intermediate portion53has an upper surface53a. The upper surface53aof the outer cup intermediate portion53is inclined obliquely upward toward an outer periphery. The inclination angle of the upper surface53aof the outer cup intermediate portion53with respect to the horizontal plane is θ4. In the present embodiment, the inclination angle θ4is not less than 5 degrees and not more than 20 degrees, for example. A distance between the upper surface53aof the outer cup intermediate portion53and the lower surface51aof the outer cup upper portion51is gradually reduced outward from the outer periphery of the substrate W. A lower engaging portion53bfor engaging the inner cup upper portion42when the inner cup4is in the lowered state is formed at the inner edge of the outer cup intermediate portion53.

The outer cup side portion52connects the outer edge of the outer cup upper portion51and the outer edge of the outer cup intermediate portion53, and is arranged to surround the inner cup lower portion41and the inner cup upper portion42. The outer cup side portion52has an inner side surface52a. The outer cup lower portion54extends downward from the lower engaging portion53bat the inner edge of the outer cup intermediate portion53and is arranged to surround the inner cup lower portion41or the inner cup upper portion42.

Hereinafter, a central portion of each lateral side in the substantially rectangular outer edge of the outer cup upper portion51is referred to as a lateral side central portion and a corner in the substantially rectangular outer edge of the outer cup upper portion51is referred to as a cup corner. Outside of the clearance S, the space V3is formed to be surrounded by the lower surface51aof the outer cup upper portion51, the inner side surface52aof the outer cup side portion52and the upper surface53aof the outer cup intermediate portion53. Hereinafter, the space V3is referred to as the scatter capturing space V3.

As described above, the outer edges of the inner cup lower portion41and the inner cup upper portion42are shaped to be substantially circular in the horizontal cross section, and the outer edges of the outer cup upper portion51, the outer cup side portion52and the outer cup intermediate portion53are shaped to be substantially rectangular in the horizontal cross section. Therefore, the scatter capturing space V3is shaped to be rectangular in the horizontal cross section. The scatter capturing space V3in the cup corner of theFIG. 3is larger than the scatter capturing space V3in the lateral side central portion ofFIG. 1. Further, in a radial direction of the substrate W, a maximal length of the scatter capturing space V3is larger than a maximal length of the collection space V1.

A drain port7is provided at the cup support member13. The drain port7is also used as an exhaust port. The drain port7is connected to a drain system P4in a factory. The drain system P4includes a drain equipment and an exhaust equipment. Processing liquid and processing gas used in the processing cup C is drained from the drain port7of the cup support member13to the drain system P4.

A current plate6is arranged below the spin holder1to surround the rotation shaft2and the motor3. The current plate6is fixed to an inner periphery of the cup support member13by a fixing member (not shown). This current plate6has an inclined surface inclined obliquely downward toward an outer periphery.

A processing liquid nozzle9that discharges the processing liquid on the substrate W is provided between a position above the substrate W and a waiting position outside of the outer cup5to be movable in the vertical direction. In the present embodiment, the processing liquid supplied from the processing liquid nozzle9is a development liquid, for example. The processing liquid may be a cleaning liquid, a rinse liquid (pure water, for example), a chemical liquid for forming an anti-reflection film on the substrate W or a resist liquid having a low viscosity. While the processing liquid preferably has a low viscosity (not more than 10 cP, for example), the invention is not limited to this.

The processing liquid nozzle9is connected to a processing liquid supply source P1through a processing liquid supply pipe T1. A valve v1is inserted into the processing liquid supply pipe T1. The valve v1is opened such that the processing liquid is supplied from the processing liquid supply source P1to the processing liquid nozzle9through the processing liquid supply pipe T1.

The substrate W is held in a horizontal attitude by the spin holder1while a surface to be processed is directed upward. In this state, the substrate W is rotated by the spin holder1and the processing liquid is discharged from the processing liquid nozzle9on the center of the surface to be processed of the substrate W. Thus, the processing liquid that has been discharged on the center of the surface to be processed of the substrate W is spread to the entire surface to be processed of the substrate W by a centrifugal force developed by the rotation of the substrate W.

In the substrate processing apparatus100, the processing liquid can be supplied to a surface that is opposite to the surface to be processed of the substrate W (hereinafter referred to as a back surface). A processing liquid nozzle8for discharging the processing liquid on the back surface of the substrate W is provided below the back surface of the substrate W. In the present embodiment, the processing liquid supplied from the processing liquid nozzle8is the cleaning liquid, for example.

The processing liquid nozzle8is connected to a processing liquid supply source P2through a processing liquid supply pipe T2. A valve v2is inserted into the processing liquid supply pipe T2. The valve v2is opened such that the processing liquid is supplied to the processing liquid nozzle8from the processing liquid supply source P2through the processing liquid supply pipe T2.

In this state, the substrate W is rotated by the spin holder1, and the processing liquid is discharged on the center of the back surface of the substrate W from the processing liquid nozzle8. Thus, the processing liquid that has been discharged on the center of the back surface of the substrate W is spread to the entire back surface of the substrate W by the centrifugal force developed by the rotation of the substrate W.

FIG. 6is a plan view of the spin holder1. As shown inFIG. 6, a plurality of (four in this example) openings H are formed in the spin holder1. The plurality of openings H are connected to a processing gas supply source P3through the rotation shaft2and a processing gas supply pipe T3inserted into the inside of the motor3ofFIGS. 1 to 3.

A valve v3is inserted into the processing gas supply pipe T3. The valve v3is opened such that the processing gas is supplied from the processing gas supply source P3to the back surface of the substrate W through the processing gas supply pipe T3and then the plurality of openings H. In the present embodiment, the processing gas supplied from the plurality of openings H is a nitrogen gas, for example. The processing gas may be another inert gas such as a helium gas, an argon gas or the like. The processing gas is supplied from the plurality of openings H to the back surface of the substrate W such that diffusion of the processing liquid that has been discharged on the back surface of the substrate W from the processing liquid nozzle8to the entire back surface of the substrate W is assisted.

The substrate processing apparatus100includes a controller12. The controller12controls a rotation speed of the motor3. Thus, the rotation speed of the substrate W held by the spin holder1is controlled. Further, the controller12controls the opening/closing of the valves v1to v3. This causes the time for supplying the processing liquid and the processing gas to be controlled. Further, the controller12controls the cylinder10. Thus, a position of the inner cup4in the vertical direction is adjusted between the lifted state and the lowered state.

(2) Processing of the Processing Liquid by the Processing Cup

FIG. 7is an enlarged cross sectional view of the section A of the processing cup C ofFIG. 1while the substrate W is rotated at a high speed. As shown inFIG. 7, when the substrate W is rotated at a higher rotation speed than a predetermined rotation speed, the processing liquid having a high kinetic energy that has been supplied on the surface to be processed of the substrate W splashes outward from the outer periphery of the substrate W with a range in the vertical direction from the surface to be processed of the substrate W. Similarly, the substrate W is rotated at the higher speed than the predetermined rotation speed of the substrate W such that the processing liquid that has been supplied to the back surface of the substrate W splashes outward from the outer periphery of the substrate W with the range in the vertical direction from the back surface of the substrate W.

The distance between the upper surface41aof the inner cup lower portion41and the lower surface42aof the inner cup upper portion42is the largest at a position that is the closest to the substrate W. Therefore, the processing liquid that has splashed outward from the substrate W is collected in the collection space V1formed between the upper surface41aof the inner cup lower portion41and the lower surface42aof the inner cup upper portion42. The collected processing liquid is led outward along the upper surface41aof the inner cup lower portion41and the lower surface42aof the inner cup upper portion42, thereby being gathered in the clearance S at the outer peripheries and passing through the clearance S.

Here, as shown inFIG. 5, because the upper surface41aof the inner cup lower portion41is inclined upward at the inclination angle θ1, the processing liquid that has splashed outward from the substrate W can be easily collected in the collection space V1. The inclination angle θ1is set to not less than 5 degrees and not more than 20 degrees such that the processing liquid that has splashed outward from the substrate W can reliably pass through the clearance S of the inner cup4. Further, the processing liquid that has hit the upper surface41aof the inner cup lower portion41can be reliably prevented from rebounding on the substrate W.

Similarly, because the lower surface42aof the inner cup upper portion42is inclined downward at the inclination angle θ2, the processing liquid adhering to the lower surface42aof the inner cup upper portion42is led to the collection space V1via the lower surface42aby the outward splashing force or gravity. Thus, the processing liquid that has splashed outward from the substrate W can be easily collected in the collection space V1. The inclination angle θ2is set to more than 0 degree and not more than 20 degrees such that the processing liquid that has splashed outward from the substrate W can reliably pass through the clearance S of the inner cup4. Further, the processing liquid that has hit the lower surface42aof the inner cup upper portion42can be reliably prevented from rebounding on the substrate W.

The processing liquid that has passed through the clearance S of the inner cup4is captured at the inner surface52aof the outer cup side portion52of the outer cup5after scattering in the scatter capturing space V3in the outer cup5. Further, the distance between the lower surface51aof the outer cup upper portion51and the upper surface53aof the outer cup intermediate portion53is gradually reduced outward from the outer peripheries of the lower surface42aof the inner cup upper portion42and the upper surface41aof the inner cup lower portion41. Thus, part of the processing liquid that has passed through the clearance S of the inner cup4is reliably led to the inner side surface52aof the outer cup side portion52by the lower surface51aof the outer cup upper portion51and the upper surface53aof the outer cup intermediate portion53.

Here, as shown inFIG. 5, because the lower surface51aof the outer cup upper portion51is inclined downward at the inclination angle θ3, the processing liquid that has passed through the clearance S of the inner cup4and has adhered to the lower surface51aof the outer cup upper portion51is led to the inner side surface52aof the outer cup side portion52via the lower surface51aby the outward splashing force or gravity. Thus, the processing liquid that has passed through the clearance S can be reliably captured in the scatter capturing space V3. The inclination angle θ3is set to more than 0 degree and not more than 20 degrees such that the processing liquid that has passed through the clearance S of the inner cup4and has hit the lower surface51aof the outer cup upper portion51can be reliably prevented from rebounding to the collection space V1.

If a plurality of blocks of the processing liquid collide and scatter in the scatter capturing space V3, a mist of the processing liquid may be generated. Even in such a case, the mist of the processing liquid is pushed back by an outward flow of the processing liquid passing through the clearance S. Thus, the mist of the processing liquid is prevented from passing through the clearance S again to return to the collection space V1between the upper surface41aof the inner cup lower portion41and the lower surface42aof the inner cup upper portion42.

When the inner cup4is in the lifted state, the inner cup upper portion42is engaged by the upper engaging portion51cof the outer cup upper portion51. Here, the inner cup upper portion42and the outer cup upper portion51are close to each other. Therefore, the mist of the processing liquid is prevented from being discharged from a clearance between the inner cup upper portion42and the outer cup upper portion51.

The processing liquid that has been captured in the scatter capturing space V3is drained from the drain port7to the drain system P4after falling on the bottom of the cup support member13ofFIG. 1by gravity. Thus, the processing liquid that has been captured in the scatter capturing space V3can be reliably drained.

The scatter capturing space V3in the cup corner of the processing cup C is larger than the scatter capturing space V3in the lateral side central portion. Thus, a size of the scatter capturing space V3can be reliably increased without increasing a size of the processing cup C as a whole. The processing liquid that has been discharged in the scatter capturing space V3in the lateral side central portion can be diffused to the scatter capturing space V3in the cup corner. Therefore, even if processing using a large amount of the processing liquid is performed in the processing cup C, the processing liquid that has splashed outward from the substrate W can be reliably prevented from adhering to the substrate W again.

Further, because the maximal length of the scatter capturing space V3is larger than the maximal length of the collection space V1in the radial direction of the substrate W, a large amount of the processing liquid can be captured in the scatter capturing space V3. Therefore, even if the large amount of the processing liquid has passed through the clearance S of the inner cup4, the processing liquid that has rebounded on the inner side surface52aof the outer cup side portion52in the direction toward the collection space V1can be reliably prevented from passing through the clearance S again to return to the collection space V1.

Further, the acquisition space V4is formed on a peripheral edge of the scatter capturing space V3. Thus, even if the processing liquid that has collided with the inner side surface52aof the outer cup side portion52is spread upward or floated up, the processing liquid is acquired in the acquisition space V4. Thus, a sufficient amount of the processing liquid can be captured or acquired in the scatter capturing space V3and the acquisition space V4in the outer cup5.

Further, the processing gas is supplied to the back surface of the substrate W from the plurality of openings H of the spin holder1ofFIG. 6. In this case, the outward force generated by the processing gas that has been supplied to the back surface of the substrate W from the processing gas supply source P3is added to the processing liquid that has been supplied to the back surface of the substrate W by the processing liquid nozzle8. The outward force is added to the centrifugal force developed by the rotation of the substrate W, whereby the processing liquid that has been supplied to the back surface of the substrate W splashes outward from the outer periphery of the substrate W with the range in the vertical direction from the back surface of the substrate W.

Here, a width of the processing liquid in the vertical direction when the processing gas is supplied is smaller than a width of the processing liquid in the vertical direction when the processing gas is not supplied. Thus, the processing liquid that has splashed outward from the outer periphery of the substrate W is reliably captured in the scatter capturing space V3in the outer cup5.

FIG. 8is an enlarged cross sectional view of the section A of the processing cup C ofFIG. 1while the substrate W is rotated at a low speed. As shown inFIG. 8, when the substrate W is rotated at a rotation speed lower than the predetermined rotation speed, the processing liquid having low kinetic energy that has been supplied to the surface to be processed of the substrate W falls downward from the outer periphery of the surface to be processed of the substrate W by gravity. Similarly, the substrate W is rotated at a rotation speed lower than the predetermined rotation speed such that the processing liquid that has been supplied to the back surface of the substrate W falls downward from the outer periphery of the back surface of the substrate W.

The processing liquid that has fallen downward from the outer periphery of the substrate W is collected in the collection space V2below the inner cup lower portion41. Thus, the processing liquid that has splashed outward from the substrate W can be prevented from adhering to the substrate W again. Further, because the processing liquid that has fallen downward from the outer periphery of the substrate W does not have high kinetic energy, the rebounded processing liquid is prevented from adhering to the substrate W again even if the plurality of blocks of the processing liquid collide and scatter in the collection space V2. The processing liquid that has been collected in the collection space V2is drained from the drain port7of the cup support member13to the drain system P4.

In the substrate processing apparatus100according to the present embodiment, the substrate W is rotated by the spin holder1. In this state, the processing liquid is supplied to the substrate W by the processing liquid nozzles8,9. The processing liquid that has splashed outward from the substrate W by the centrifugal force developed by the rotation of the substrate W is collected in the collection space V1. The collected processing liquid is led outward along the upper surface41aof the inner cup lower portion41and the lower surface42aof the inner cup upper portion42, thereby being gathered in the clearance S at the outer peripheries and passing through the clearance S.

The processing liquid that has passed through the clearance S of the inner cup4is captured at the inner side surface52aof the outer cup side surface52after scattering in the scatter capturing space V3in the outer cup5. Further, part of the processing liquid that has passed through the clearance S is led to the inner side surface52aof the outer cup side portion52by the lower surface51aof the outer cup upper portion51.

This configuration causes the processing liquid that has once passed outward through the clearance S of the inner cup4to be sufficiently captured in the scatter capturing space V3in the outer cup5, thereby not passing through the clearance S again to return to the collection space V1. As a result, the processing liquid that has splashed outward from the substrate W can be reliably prevented from adhering to the substrate W again.

(4) Other Embodiments

(4-1) While the lower surface42aof the inner cup upper portion42is inclined obliquely downward toward the outer periphery in the embodiment described above, the invention is not limited to this. The lower surface42aof the inner cup upper portion42may horizontally extend outward.

(4-2) While the lower surface51aof the outer cup upper portion51is inclined obliquely downward toward the outer periphery in the embodiment described above, the invention is not limited to this. The lower surface51aof the outer cup upper portion51may horizontally extend outward.

(4-3) While the scatter capturing space V3is shaped to be rectangular in the horizontal cross section in the embodiment described above, the invention is not limited to this. The scatter capturing space V3may be shaped to be non-circular such as polygonal, oval, elliptical or the like. If the size of the processing cup C may be increased, the scatter capturing space V3may be shaped to be circular in the horizontal cross section.

(4-4) While the plurality of openings H are formed at the spin holder1and the processing gas is supplied from the openings H of the spin holder1in the embodiment described above, the invention is not limited to this. Another nozzle for supplying the processing gas may be provided below the back surface of the substrate W and the processing gas may be supplied to the back surface of the substrate W from the nozzle for supplying the processing gas. In this case, the plurality of openings H do not have to be provided at the spin holder1.

(5) Correspondences between Constituent Elements in Claims and Parts in Preferred Embodiments

In the following paragraphs, non-limiting examples of correspondences between various elements recited in the claims below and those described above with respect to various preferred embodiments of the present invention are explained.

In the embodiment described above, the substrate W is an example of a substrate, the processing cup C is an example of a processing cup, the inner cup4is an example of a first cup, the outer cup5is an example of a second cup, the inner cup lower portion41is an example of a first member and the inner cup upper portion42is an example of a second member. The upper surface41ais an example of a first upper surface, the lower surface42ais an example of a first lower surface, the upper surface53ais an example of a second upper surface, the lower surface51ais an example of a second lower surface, the inner side surface52ais an example of an inner side surface and the drain port7is an example of a drain port.

The clearance S is an example of a clearance, the collection spaces V1, V2are examples of first and second collection spaces, respectively, the scatter capturing space V3is an example of a scatter capturing space, the acquisition space V4is an example of an acquisition space and the inclination angles θ1to θ3are examples of first to third angles, respectively. The substrate processing apparatus100is an example of a substrate processing apparatus, the spin holder1is an example of a spin holder, the processing liquid nozzles9,8are examples of first and second processing liquid supply systems, respectively, and the opening H is an example of a processing gas supply system.