Patent Publication Number: US-2006000704-A1

Title: Solution treatment apparatus and solution treatment method

Description:
TECHNICAL FIELD  
      The present invention relates to a solution treatment apparatus and a solution treatment method for applying solution treatment on a substrate.  
     BACKGROUND ART  
      The recent improvement in integration degree of semiconductor devices has promoted the utilization of a buried wiring method in which wiring is formed by burying metal in wiring trenches or connection holes formed in a semiconductor wafer (hereinafter, simply referred to as a “wafer”). This has given rise to a strong demand for the development of a deposition apparatus having a high burying speed. Currently, an electrolytic plating apparatus has been drawing attention as a deposition apparatus satisfying such a demand.  
      In the electrolytic plating apparatus, a wafer is immersed in a plating solution in a plating solution tank and a voltage is applied between anode electrodes and cathode electrodes that are in contact with a periphery portion of the wafer, thereby burying plating.  
      However, electricity is supplied from the periphery portion of the wafer in such an electrolytic plating apparatus, so that the wafer has a larger current density in the periphery portion than in a center portion, which poses a problem of low plating uniformity in a surface.  
      At present, as one method of solving the above-described problem, Japanese Patent Laid-Open Application No. 2000-87285 and Japanese Patent Laid-Open Application No. 2000-96282 disclose a method of controlling the current density by disposing a movable shielding plate in a plating solution tank and moving the shielding plate during a plating process.  
      In the above-described method, however, since the shielding plate changes the flow of the plating solution, uniformity of flow velocity distribution is deteriorated, which poses such a problem that plating uniformity in the surface cannot be effectively improved. Note that this problem is a problem resulting from the disposition of the shielding plate and thus is a problem also arising when the shielding plate is not moved during the plating process.  
     DISCLOSURE OF THE INVENTION  
      The present invention is made to solve the problems stated above. Therefore, the object thereof is to provide a solution treatment apparatus and a solution treatment method capable of effectively improving uniformity of solution treatment in a surface of a substrate.  
      A solution treatment apparatus according to an aspect of the present invention includes: a treatment solution tank configured to store a treatment solution in which a substrate is to be immersed; a first electrode in electrical contact with the substrate immersed in the treatment solution; a second electrode disposed in the treatment solution tank, a voltage being applied between the second electrode and the first electrode; a diaphragm disposed between the substrate and the second electrode; and a diaphragm position varying mechanism configured to partly vary a position of the diaphragm. The solution treatment apparatus according to this invention has the diaphragm position varying mechanism, so that the position of the diaphragm is partly variable. This enables effective improvement in uniformity of solution treatment in a surface of the substrate.  
      It is preferable that, in a state before the position of the diaphragm is partly varied, a portion of the diaphragm facing a center portion of the substrate is positioned closer to a substrate side than a portion of the diaphragm facing a periphery portion of the substrate. The use of such a diaphragm can facilitate effective improvement in uniformity of solution treatment in a surface of the substrate.  
      The diaphragm position adjusting mechanism preferably moves a portion of the diaphragm facing a center portion of the substrate. The movement of such a portion can facilitate partly changing the position of the diaphragm.  
      It is preferable to further provide a controller configured to control the diaphragm position varying mechanism. When the controller is provided, the diaphragm position adjusting mechanism can be automatically controlled.  
      It is preferable that the solution treatment apparatus further includes a sensor configured to partly measure a degree of solution treatment applied on the substrate, and that the controller controls the diaphragm position varying mechanism based on a result of the measurement by the sensor. The provision of the sensor and such control by the controller enable more effective improvement in uniformity of solution treatment in a surface of the substrate.  
      It is preferable that the solution treatment apparatus further includes a measurement substrate having a plurality of electrodes and an ammeter configured to measure a current passing through each of the electrodes, and that the controller controls the diaphragm position varying mechanism based on a result of the measurement by the ammeter. The provision of the measurement substrate and such control by the controller enable more effective improvement in uniformity of solution treatment in a surface of the substrate.  
      A solution treatment apparatus according to another aspect of the present invention includes: a treatment solution tank configured to store a treatment solution in which a substrate is to be immersed; a first electrode in electrical contact with the substrate immersed in the treatment solution; a second electrode disposed in the treatment solution tank, a voltage being applied between the first electrode and the second electrode; and a diaphragm disposed between the substrate and the second electrode, a portion of the diaphragm facing a center portion of the substrate being positioned closer to a substrate side than a portion of the diaphragm facing a periphery portion of the substrate. The solution treatment apparatus according to this invention has such a diaphragm, which enables effective improvement in uniformity of solution treatment in a surface of the substrate.  
      A solution treatment method according to still another aspect of the present invention includes: immersing a substrate in a treatment solution in a treatment solution tank and passing a current through the immersed substrate to apply solution treatment on the substrate; and partly measuring a degree of the solution treatment applied on the substrate while the solution treatment is being applied on the substrate, and partly varying a position of a diaphragm disposed in the treatment solution tank based on a result of the measurement, to adjust the degree of the solution treatment in the substrate. The solution treatment method of this invention thus adjusts the degree of the solution treatment, which enables effective improvement in uniformity of solution treatment in a surface of the substrate.  
      A solution treatment method according to yet another aspect of the present invention includes: immersing a measurement substrate having a plurality of electrodes in a treatment solution in a treatment solution tank and passing a current through each of the electrodes of the immersed measurement substrate to apply solution treatment on the measurement substrate while measuring the current passing through each of the electrodes; immersing a substrate in the treatment solution in the treatment solution tank and passing a current through the immersed substrate to apply solution treatment on the substrate; and partly varying a position of a diaphragm disposed in the treatment solution tank based on a result of the measurement while the solution treatment is being applied on the substrate, to adjust a degree of the solution treatment in the substrate. The solution treatment method according to this invention thus adjusts the degree of the solution treatment, which enables effective improvement in uniformity of solution treatment in a surface of the substrate. 
    
    
     BRIEF DESCRIPTION OF DRAWINGS  
       FIG. 1  is a schematic vertical sectional view of an electrolytic plating apparatus according to a first embodiment.  
       FIG. 2  is a schematic plane view of a diaphragm and a frame according to the first embodiment.  
       FIG. 3  is a schematic vertical sectional view of a wafer according to the first embodiment.  
       FIG. 4  is a flowchart showing the flow of a process executed in the electrolytic plating apparatus according to the first embodiment.  
       FIG. 5  is a flowchart showing the flow of a plating process according to the first embodiment.  
       FIG. 6A  and  FIG. 6B  are views schematically showing the state in the electrolytic plating apparatus according to the first embodiment.  
       FIG. 7  is a schematic plane view of a dummy wafer according to a second embodiment.  
       FIG. 8  is a view showing the state in a holder vessel when the dummy wafer according to the second embodiment is housed in the holder vessel.  
       FIG. 9  is a flowchart showing the flow of a process executed in an electrolytic plating apparatus according to the second embodiment.  
       FIG. 10  is a flowchart showing the flow of a plating process in the dummy wafer executed in the electrolytic plating apparatus according to the second embodiment.  
       FIG. 11A  to  FIG. 11C  are views schematically showing the state in the electrolytic plating apparatus according to the second embodiment.  
       FIG. 12  is a flowchart showing the flow of a process executed in an electrolytic plating apparatus according to a third embodiment.  
       FIG. 13  is a flowchart showing the flow of a plating process in a dummy wafer executed in the electrolytic plating apparatus according to the third embodiment.  
       FIG. 14  is a view schematically showing the state in the electrolytic plating apparatus according to the third embodiment. 
    
    
     BEST MODE FOR CARRYING OUT THE INVENTION  
     First Embodiment  
      An electrolytic plating apparatus according to a first embodiment will be hereinafter explained.  FIG. 1  is a schematic vertical sectional view of the electrolytic plating apparatus according to, this embodiment, and  FIG. 2  is a schematic plane view of a diaphragm and a frame according to this embodiment.  FIG. 3  is a schematic vertical sectional view of a wafer according to this embodiment.  
      As shown in  FIG. 1  and  FIG. 2 , an electrolytic plating apparatus  1  has a housing  2  made of synthetic resin or the like. An opening  2 A is formed on a sidewall of the housing  2 . A gate valve  3  that opens/closes when a wafer  100  is carried into and out of the electrolytic plating apparatus  1  is disposed on an outer side of the opening  2 A.  
      A holder  4  to hold the wafer  100  is disposed in the housing  2 . The wafer  100  is held by the holder  4  in a so-called facedown manner so that a surface to be plated of the wafer  100  faces downward.  
      The holder  4  has a holder vessel  5  in a substantially cylindrical shape for housing the wafer  100  in its inner space substantially horizontally. An opening  5 A in a substantially circular shape for allowing the surface to be plated of the wafer  100  to be in contact with a plating solution is formed on a bottom face of the holder vessel  5 . The opening  5 A is formed to have a diameter smaller than that of the wafer  100 .  
      An opening  5 B through which the wafer  100  is to be carried into or out of the holder vessel  5  is formed on a side face of the holder vessel  5 . A shutter  6  that can be freely opened/closed is disposed on an outer side of the opening  5 B. After the wafer  100  is carried in, the shutter  6  is closed to cover the opening  5 B, so that the entrance of the plating solution into the holder vessel  5  is prevented.  
      A motor  7  to rotate the holder vessel  5  in a substantially horizontal plane is connected to the holder vessel  5 . Note that the wafer  100  rotates with the holder vessel  5  when the holder vessel  5  rotates.  
      A holder vessel hoisting/lowering mechanism  8  to hoist/lower the holder vessel  5  is attached to the motor  7 . The holder vessel hoisting/lowering mechanism  8  is composed of a support beam  9  attached to the motor  7 , a guide rail  10  attached to an inner wall of the housing  2 , and an air cylinder  11  having an extendible/contractible rod  11 A and hoisting/lowering the support beam  9  along the guide rail  10 . The actuation of the air cylinder  11  causes the rod  11 A to extend/contract, so that the holder vessel  5  is hoisted/lowered along the guide rail  10 .  
      Specifically, the holder vessel  5  is hoisted/lowered by the holder vessel hoisting/lowering mechanism  8  among a transfer position (I) where the wafer  100  is transferred, a cleaning position (II) where plating applied on the wafer  100  is cleaned, a spin-dry position (III) where the plated wafer  100  is spin-dried for the removal of an unnecessary plating solution or water therefrom, and a plating position (IV) where the wafer  100  is plated. Incidentally, when the plating solution is filled in an inner tank  19  which will be described later, the transfer position (I), the cleaning position (II), and the spin-dry position (III) are positioned higher than the level of the plating solution, and the plating position (IV) is positioned lower than the level of the plating solution.  
      A seal member  12  that prevents later-described cathode electrodes  15  from coming into contact with the plating solution is disposed in the holder vessel  5 . A suction pad  13  for holding the wafer.  100  and placing the wafer.  100  on the seal member  12 , and a pressing member  14  for pressing the wafer  100  placed on the seal member  12  against the seal member  12  are further disposed in the holder vessel  5 .  
      The plural cathode electrodes  15  to be in electrical contact with the wafer  100  are disposed on the seal member  12 . The plural cathode electrodes  15  are provided, so that electricity is supplied from a plurality of places, resulting in uniform current passage through the wafer  100 . The cathode electrodes  15  are formed of a material excellent in electrical conductivity, for example, Au, Pt, or the like.  
      Hemispheric contacts  16  which are brought into contact with an outer periphery portion of the surface to be plated of the wafer  100  at, for example,  128  equally divided positions are protrudingly provided on the cathode electrodes  15 . By the hemispheric formation of the contacts  16 , each of the contacts  16  is in contact with the wafer  100  with a constant area.  
      The wafer  100  to be in contact with the contacts  16  includes an interlayer insulation film  101  in which wiring trenches  101 A are formed, as shown in  FIG. 3 . The interlayer insulation film  101  is preferably formed of a low dielectric constant material, for example, SiOF, SiOC, porous silica, or the like. Further, connection holes may be formed in the interlayer insulation film  101  in place of or in addition to the wiring trenches  101 A.  
      A barrier film  102  to inhibit the diffusion of the plating to the interlayer insulation film  101  is formed on the interlayer insulation film  101 . The barrier film  102  is preferably formed of, for example, TaN, TiN, or the like. Further, the barrier film  102  is formed on the interlayer insulation film  101  to have a thickness of about 30 nm.  
      A seed film  103  for allowing a current to pass through the wafer  100  is formed on the barrier film  101 . The seed film  103  is preferably formed of the same metal as the plating. Specifically, if the plating is, for example, Au, Ag, Pt, Cu, or the like, the seed film  103  is preferably formed of, for example, Au, Ag, Pt, Cu, or the like in conformity to the plating. Further, the seed film  103  is formed on the barrier film  102  to have a thickness of about 100 nm.  
      A plating solution tank  17  for storing the plating solution therein is disposed beneath the holder  4 . The plating solution tank  17  is constituted of an outer tank  18  and an inner tank  19  disposed inside the outer tank  18 . The outer tank  18  is intended for receiving the plating solution overflowing from the inner tank  19 . The outer tank  18  is formed in a substantially cylindrical shape with its top face opened and bottom face closed. A drainpipe  20  through which the plating solution is drained from the outer tank  18  is connected to a bottom portion of the outer tank  118 . The other end of the drainpipe  20  is connected to a not-shown reservoir tank in which the plating solution to be supplied to the inner tank  19  is stored. A valve  21  is disposed in the middle of the drainpipe  20 . When the valve  21  is opened, the plating solution overflowing from the inner tank  19  and flowing into the outer tank  18  is returned to the reservoir tank.  
      On an upper portion of the outer tank  18 , an exhaust member  22  having an exhaust port to suck the vaporized plating solution or the scattered plating solution and a washing nozzle  23  to clean the plating applied on the wafer  100  are disposed.  
      The inner tank  19  is intended for storing the plating solution in which the wafer  100  is to be immersed. Similarly to the outer tank  18 , the inner tank  19  is formed in a substantially cylindrical shape with its top face opened and bottom face closed. An anode electrode  24  is disposed on the bottom portion of the inner tank  19 , a voltage being applied between the cathode electrodes  15  and the anode electrode  24 . The anode electrode  24  is electrically connected to a not-shown external power source.  
      A diaphragm  25  that partitions the inside of the inner tank  19  to an upper region and a lower region is disposed above the anode electrode  24 . Here, the lower region and the upper region separated by the diaphragm  25  are called an anode region and a cathode region respectively. The diaphragm  25  is an ion conductive film. Specifically, the diaphragm  25  is mainly made of titanium oxide, polyvinylidene fluoride, and so on.  
      The diaphragm  25  is constituted of a plurality, six pieces in this embodiment, of diaphragm pieces arranged in a ring form. The diaphragm  25  is supported by a frame  26  formed of a transformable material, for example, polyethylene.  
      A periphery portion of the frame  26  is fixed to the inner tank  19 . An opening  26 A is formed on a center portion of the frame  26 , and a tip portion of a later-described supply pipe  35  is liquid-tightly connected to the opening  26 A. The center portion of the frame  26  is positioned closer to a wafer  100  side than the periphery portion of the frame  26 . Specifically, the frame  26  is formed in a dome shape in this embodiment. The frame  26  is formed in such a shape, so that a portion  25 A (hereinafter, referred to as a center facing portion  25 A) of the diaphragm  25  facing a center portion  100 A of the wafer  100  is positioned closer to the wafer  100  side than a portion  25 B (hereinafter, referred to as a periphery facing portion  25 B) of the diaphragm  25  facing a periphery portion  100 B of the wafer  100 .  
      A light-emitting element  27  to emit light at a predetermined angle to the wafer  100  and light-receiving elements  28  to detect the light reflected on the wafer  100  are provided in the inner tank  19 . The light-emitting element  27  is constituted of a light-emitting element  27 A to emit light at a predetermined angle to the center portion  100 A of the wafer  100  and a light-emitting element  27 B to emit light at a predetermined angle to the periphery portion  100 B of the wafer  100 . The plural light-receiving elements  28  are arranged in line. The light-emitting element  27  and the light-receiving elements  28  are disposed, so that the film thickness of the plating can be measured. To be more specific, as the plating of the wafer  100  progresses, the reflection position of the light emitted from the light-emitting element  27  shifts toward the light-emitting element  27  side. When the reflection position shifts toward the light-emitting element  27  side, the reflected light moves downward to cause the change in the light-receiving position. This change in the light-receiving position is detected by the light-receiving elements  28 , so that a later-described controller  39  can calculate the film thickness of the plating.  
      A supply pipe  29  through which the plating solution is supplied to the anode region and a drainpipe  30  through which the plating solution is drained from the anode region are connected to the bottom portion of the inner tank  19 . Valves  31 ,  32  that can be opened/closed freely and pumps  33 ,  34  capable of adjusting a flow rate of the plating solution are provided in the middle of the supply pipe  29  and the drain pipe  30  respectively. When the pump  33  is put into operation while the valve  31  is open, the plating solution in the reservoir tank is sent to the anode region at a predetermined flow rate. Further, when the pump  34  is put into operation while the valve  32  is open, the plating solution in the anode region is returned to the reservoir tank.  
      The supply pipe  35  through which the plating solution is supplied to the cathode region protrudes into the inner tank  19 . The other end of the supply pipe  35  is connected to the not-shown reservoir tank. A valve  36  that can be opened and closed freely and a pump  37  capable of adjusting the flow rate of the plating solution are provided in the middle of the supply pipe  35 . When the pump  37  is put into operation while the valve  36  is open, the plating solution in the reservoir tank is sent to the cathode region at a predetermined flow rate.  
      A supply pipe extending/contracting mechanism  38  that extends/contracts the supply pipe  35  in a thickness direction of the wafer  100  is attached to the supply pipe  35 . Here, the frame  26  supporting the diaphragm  25  is connected to the tip of the supply pipe  35 , so that the extension/contraction of the supply pipe  35  by the operation of the supply pipe extending/contracting mechanism  38  causes the center portion of the frame  26  and the center facing portion  25 A of the diaphragm  25  to vertically move.  
      The controller  39  that controls the operation of the supply pipe extending/contracting mechanism  38  is electrically connected to the supply pipe extending/contracting mechanism  38 . The controller  39  is electrically connected to the light-receiving elements  28  as well. The controller  39  controls the operation of the supply pipe extending/contracting mechanism  38  based on output signals from the light-receiving elements  28 . Specifically, the controller  39  calculates the film thickness of the center portion  100 A of the wafer  100  and the film thickness of the periphery portion  100 B thereof based on the output signals from the light-receiving elements  28  to judge whether or not the film thickness of the center potion  10 A is larger than the film thickness of the periphery portion  100 B. When judging that the film thickness of the center portion  100 A is larger than the film thickness of the periphery portion  100 B, it outputs to the supply pipe extending/contracting mechanism  38  a control signal causing the supply pipe  35  to contract. When judging that the film thickness of the center portion  100 A is smaller than the film thickness of the periphery portion  100 B, it outputs to the supply pipe extending/contracting mechanism  38  a control signal causing the supply pipe  35  to extend.  
      Hereinafter, the flow of a process executed in an electrolytic plating apparatus  1  will be explained with reference to  FIG. 4  to  FIG. 6B .  FIG. 4  is a flowchart showing the flow of a process executed in the electrolytic plating apparatus  1  according to this embodiment,  FIG. 5  is a flowchart showing the flow of a plating process according to this embodiment, and  FIG. 6A  and  FIG. 6B  are views schematically showing the state inside the electrolytic plating apparatus  1  according to this embodiment.  
      First, while the gate valve  3  is open, a not-shown carrier arm holding the wafer  100  extends into the holder vessel  5  positioned at the transfer position (I) to carry the wafer  100  into the electrolytic plating apparatus  1  (Step IA).  
      After the wafer  100  is carried into the electrolytic plating apparatus  1 , the wafer  100  is suction-held by the suction pad  13 . Subsequently, the suction pad  13  moves down to place the wafer  100  on the seal member  12 . Thereafter, the pressing member  14  moves down to press the wafer  100  against the seal member  12 . With this process, the wafer  100  is held by the holder  4  (Step  2 A).  
      After the wafer  100  is held by the holder  4 , the air cylinder  11  is actuated to lower the holder vessel  5  to the plating position (IV), so that the wafer  100  is immersed in the plating solution. After the holder vessel  5  is positioned at the plating position (IV), the wafer  100  is plated while the operation of the supply pipe extending/contracting mechanism  38  is being controlled (Step  3 A).  
      Specifically, a voltage is first applied between the anode electrode  24  and the cathode electrodes  15 . Further, the light-emitting element  27  is lighted, so that the light is emitted from the light-emitting element  27 . (Step  3 A 1 ). Thereafter, the controller  39  calculates the film thickness of the center portion  100 A of the wafer  100  and the film thickness of the periphery portion  100 B thereof based on the output signals from the light-receiving elements  28  to judge whether or not the film thickness of the center portion  100 A is larger than the film thickness of the periphery portion  100 B (Step  3 A 2 ). When it is judged that the film thickness of the center portion  100 A is larger than the film thickness of the periphery portion  100 B, the supply pipe  35  contracts as shown in  FIG. 6A  to lower the center facing portion  25 A (Step  3 A 3 ). On the other hand, when it is judged that the film thickness of the center portion  100 A is smaller than the film thickness of the periphery portion  100 B, the supply pipe  35  extends as shown in  FIG. 6B  to lift the center facing portion  25 A (Step  3 A 4 ). Thereafter, it is judged whether or not a predetermined period of time has passed from the start of the plating (Step  3 A 5 ). When it is judged that the predetermined period of time has not passed from the start of the plating, the processes from Step  3 A 2  to Step  3 A 4  are repeated. When it is judged that the predetermined period of time has passed from the start of the plating, the voltage application is stopped and the lighting of the light-emitting element  27  is stopped (Step  3 A 6 ). With this process, the plating of the wafer  100  is finished.  
      After the plating of the wafer  100  is finished, the air cylinder  11  is actuated to lift the holder vessel  5  to the spin-dry position (III). After the holder vessel  5  is positioned at the spin-dry position (III), the holder vessel  5  is rotated in a substantially horizontal plane by the drive of the motor  7  for spin dry (Step  4 A).  
      After the spin dry is finished, the air cylinder  11  is actuated to lift the holder vessel  5  to the cleaning position (II). After the holder vessel  5  is positioned at the cleaning position (II), the holder vessel  5  is rotated in a substantially horizontal plane by the drive of the motor  7  and pure water is sprayed to the wafer  100  from the washing nozzle  23  to clean the plating applied on the wafer  100  (Step  5 A).  
      After the cleaning of the plating is finished, the air cylinder  11  is actuated to lower the holder vessel  5  to the spin-dry position (III). After the holder vessel  5  is positioned at the spin-dry position (III), the holder vessel  5  is rotated in a substantially horizontal plane by the drive of the motor  7  spin dry (Step  6 A).  
      After the spin dry is finished, the air cylinder  11  is actuated to lift the holder vessel  5  to the transfer position (I). After the holder vessel  5  is positioned at the transfer position (I), the pressing member  14  moves up to release the pressing to the wafer  100 . Thereafter, the suction pad  13  moves up to have the wafer  100  apart from the seal member  12 . With this process, the holding of the wafer  100  by the holder  4  is released (Step  7 A).  
      After the holding of the wafer  100  is released, the shutter  6  and the gate valve  3  are opened, and the not-shown carrier arm extends into the holder vessel  5  to receive the wafer  100 . Thereafter, the carrier arm holding the wafer  100  contracts to carry the wafer  100  out of the electrolytic plating apparatus  1  (Step  8 A).  
      In this embodiment, the center facing portion  25 A is moved relative to the periphery portion  25 B during the plating process based on the film thicknesses of the plating applied on the center portion  10 A and the periphery portion  10 B, which enables effective improvement in plating uniformity in a surface. Specifically, the diaphragm  25  gives an influence to the current density due to its ion conductivity. To be more specific, as the distance from the wafer  100  to the diaphragm  25  decreases, the current density in the wafer  100  increases, and as the distance from the wafer  100  to the diaphragm  25  increases, the current density decreases. Therefore, when the center facing portion  25 A moves down to increase the distance between the center portion  100 A and the center facing portion  25 A, the current density of the center portion  100 A decreases, and when the center facing portion  25 A moves up to decrease the distance between the center portion  100 A and the center facing portion  25 A, the current density of the center portion  100 A increases. Here, in this embodiment, the center facing portion  25 A moves up or down based on the film thicknesses of the plating applied on the center portion  100 A and the periphery portion  100 B. Since a shielding plate is not provided, the plating solution in the cathode region flows smoothly. As a result, higher uniformity of the flow velocity distribution can be realized than that when the shielding plate is provided. Therefore, plating uniformity in a surface can be effectively improved.  
      In this embodiment, since the center facing portion  25 A is moved, partial change in the distance between the wafer  100  and the diaphragm  25  can be more easily made than when the periphery facing portion  25 B is moved.  
     Second Embodiment  
      Hereinafter, a second embodiment will be explained. Note that in this embodiment and a subsequent embodiment, the same contents as those in the previous embodiment(s) will be omitted in some cases. The explanation in this embodiment will be given on an example where, through the use of a dummy wafer, a current passing through a center portion and a current passing through a periphery portion are measured and a wafer is plated based on the currents.  FIG. 7  is a schematic plane view of a dummy wafer according to this embodiment, and  FIG. 8  is a view showing the state in a holder vessel when the dummy wafer according to this embodiment is housed in the holder vessel.  
      As shown in  FIG. 7  and  FIG. 8 , a dummy wafer  200  has a monitor electrode support plate  201  formed of, for example, synthetic resin or the like, and supporting later-described monitor electrodes  202 . A plurality of openings are formed in the monitor electrode support plate  201 , and the monitor electrodes  202  formed of, for example, Cu, Pt, or the like are buried in these openings.  
      The monitor electrodes  202  are buried in such a manner, for example, that the entire monitor electrodes  202  form a plurality of rings concentric with the monitor electrode support plate  201 . Note that, for example,  64  or  128  pieces of the monitor electrodes  202  are buried in a periphery portion of the monitor electrode support plate  201 .  
      Lead wires  203  for electrical contact between the monitor electrodes  202  and contacts  16  are connected to the monitor electrodes  202 . When the dummy wafer  200  is placed on the contacts  16 , the lead wires  203  come into contact with the contacts  16  to bring the monitor electrodes  202  and the contacts  16  in electrical contact with each other. Ammeters  204  to measure currents passing through the monitor electrodes  202  are provided in the middle of the lead wires  203 , and a controller  39  is electrically connected to the ammeters  204 .  
      The controller  39  controls the operation of a supply pipe extending/contracting mechanism  38  based on output signals from the ammeters  204 . Specifically, the controller  39  judges, based on the output signal from the ammeters  204 , whether or not a current passing through a center portion  200 A of the dummy wafer  200  is larger than a current passing through a periphery portion  200 B thereof. When judging that the current passing through the center portion  200 A is larger than the current passing through the periphery portion  200 B, it outputs to the supply pipe extending/contracting mechanism  38  a control signal causing a supply pipe  35  to contract. On the other hand, when judging that the current passing through the center portion  200 A is smaller than the current passing through the periphery portion  200 B, it outputs to the supply pipe extending/contracting mechanism  38  a control signal causing the supply pipe  35  to extend. Here, the control signal outputted when the dummy wafer  200  is plated is stored in the controller  39 , and the stored control signal is outputted when a wafer  100  is plated. Consequently, the control over the supply pipe extending/contracting mechanism  38  that is performed when the dummy wafer  200  is plated is reproduced when the wafer  100  is plated.  
      Hereinafter, the flow of a process executed in an electrolytic plating apparatus  1  will be explained with reference to  FIG. 9  to  FIG. 11 .  FIG. 9  is a flowchart showing the flow of a process executed in the electrolytic plating apparatus  1  according to this embodiment,  FIG. 10  is a flowchart showing the flow of the plating process in the dummy wafer  200  executed in the electrolytic plating apparatus  1  according to this embodiment, and  FIG. 11A  to  FIG. 11C  are views schematically showing the state in the electrolytic plating apparatus  1  according to this embodiment.  
      First, while a gate valve  3  is open, a not-shown carrier arm holding the dummy wafer  200  extends into a holder vessel  5  to carry the dummy wafer  200  into the electrolytic plating apparatus  1  (Step  1 B).  
      After the dummy wafer  200  is carried into the electrolytic plating apparatus  1 , the dummy wafer  200  is suction-held by a suction pad  13 . Subsequently, the suction pad  13  moves down to place the dummy wafer  200  on a seal member  12 . Thereafter, a pressing member  14  moves down to press the dummy wafer  200  against the seal member  12 . With this process, the dummy wafer  200  is held by a holder  4  (Step  2 B).  
      After the dummy wafer  200  is held by the holder  4 , the holder vessel  5  moves down to a plating position (IV), so that the dummy wafer  200  is immersed in a plating solution. After the holder vessel  5  is positioned at the plating position (IV), the dummy wafer  200  is plated while the operation of the supply pipe extending/contracting mechanism  38  is being controlled (Step  3 B).  
      Specifically, a voltage is first applied between an anode electrode  24  and cathode electrodes  15  (Step  3 B 1 ). Thereafter, the controller  39  judges whether or not the current passing through the center portion  200 A of the dummy wafer  200  is larger than the current passing through the periphery portion  200 B thereof based on the output signals from the ammeters  204  (Step  3 B 2 ). When it is judged that the current passing through the center portion  200 A is larger than the current passing through the periphery portion  200 B, the supply pipe  35  contracts as shown in  FIG. 1A  to lower a center facing portion  25 A (Step  3 B 3 ). On the other hand, when it is judged that the current passing through the center portion  200 A is smaller than the current passing through the periphery portion  200 B, the supply pipe  35  extends as shown in  FIG. 11B  to lift the center facing portion  25 A (Step  3 B 4 ). Thereafter, it is judged whether or not a predetermined period of time has passed from the start of the plating (Step  3 B 5 ). When it is judged that the predetermined period of time has not passed from the start of the plating, the processes from Step  3 B 2  to Step  3 B 5  are repeated. When it is judged that the predetermined period of time has passed from the start of the plating, the voltage application is stopped (Step  3 B 6 ). With this process, the plating of the dummy wafer  200  is finished.  
      After the plating of the dummy wafer  200  is finished, the holder vessel  5  moves up to a transfer position (I). After the holder vessel  5  is positioned at the transfer position (I), the pressing member  14  moves up to release the pressing to the dummy wafer  200 . Thereafter, the suction pad  13  moves up to have the dummy wafer  200  apart from the seal member  12 . With this process, the holding of the dummy wafer  200  by the holder  4  is released (Step  4 B)  
      After the holding of the dummy wafer  200  is released, the carrier arm receives the dummy wafer  200 . Thereafter, the carrier arm holding the dummy wafer  200  contracts to carry the dummy wafer  200  out of the housing  2  (Step  5 B).  
      After the dummy wafer  200  is carried out of the electrolytic plating apparatus  1 , a not-shown carrier arm holding the wafer  100  extends into the holder vessel  5  to carry the wafer  100  into the electrolytic plating apparatus  1  (Step  6 B).  
      After the wafer  100  is carried into the electrolytic plating apparatus  1 , the wafer  100  is suction-held by the suction pad  13 . Subsequently, the suction pad  13  moves down to place the wafer  100  on the seal member  12 . Thereafter, the pressing member  14  moves down to press the wafer  100  against the seal member  12 . With this process, the wafer  100  is held by the holder  4  (Step  7 B).  
      After the wafer  100  is held by the holder  4 , the holder vessel  5  moves down to the plating position (IV), so that the wafer  100  is immersed in the plating solution. After the holder vessel  5  is positioned at the plating position (IV), a voltage is applied between the anode electrode  24  and the cathode electrodes  15 , and the wafer  100  is plated while the movement of the center facing portion  25 A that was made when the dummy wafer  200  was plated is reproduced, as shown in  FIG. 11C  (Step  8 B).  
      After the plating of the wafer  100  is finished, the holder vessel  5  moves up to a spin-dry position (III). After the holder vessel  5  is positioned at the spin-dry position (III), the holder vessel  5  is rotated in a substantially horizontal plane for spin dry (Step  9 B).  
      After the spin dry is finished, the holder vessel  5  moves up to a cleaning position (II). After the holder vessel  5  is positioned at the cleaning position (II), the holder vessel  5  is rotated in a substantially horizontal plane and pure water is sprayed to the wafer  100  from a washing nozzle  23  to clean the plating applied on the wafer  100  (Step  10 B).  
      After the plating is cleaned, the holder vessel  5  moves down to the spin-dry position (III). After the holder vessel  5  is positioned at the spin-dry position (III), the holder vessel  5  is rotated in a substantially horizontal plane for spin dry (Step  1 B).  
      After the spin dry is finished, the holder vessel  5  moves up to the transfer position (I). After the holder vessel  5  is positioned at the transfer position (I), the pressing member  14  moves up to release the pressing to the wafer  100 . Thereafter, the suction pad  13  moves up to have the wafer  100  apart from the seal member  12 . With this process, the holding of the wafer  100  by the holder  4  is released (Step  12 B).  
      After the holding of the wafer  100  is released, the carrier arm receives the wafer  100 . Thereafter, the carrier arm holding the wafer  100  contracts to carry the wafer  100  out of the electrolytic plating apparatus  1  (Step  13 B).  
     Third Embodiment  
      Hereinafter, a third embodiment will be explained. The explanation in this embodiment will be given on an example where the positioning of a center facing portion is made through the use of a dummy wafer, and thereafter a wafer is plated with the center facing portion being fixed.  
      A controller  39  controls the operation of a supply pipe extending/contracting mechanism  38  based on output signals from ammeters  204 . Specifically, it is judged, based on the output signals from the ammeters  204 , whether or not the difference between a current passing through a center portion  200 A of a dummy wafer  200  and a current passing through a periphery portion  200 B thereof is within a predetermined range. When the difference between the current passing through the center portion  200 A and the current passing through the periphery portion  200 B is not within the predetermined range, it is judged whether or not the current passing through the center portion  200 A is larger than the current passing through the periphery portion  200 B. When the current passing through the center portion  200 A is larger than the current passing through the periphery portion  200 B, a control signal causing a supply pipe  35  to contract is outputted to the supply pipe extending/contracting mechanism  38 . On the other hand, when it is judged that the current passing through the center portion  200 A is smaller than the current passing through the periphery portion  200 B, a control signal causing the supply pipe  35  to extend is outputted to the supply pipe extending/contracting mechanism  38 . On the other hand, when the difference between the current passing through the center portion  200 A and the current passing through the periphery portion  200 B is within the predetermined range, a control signal causing the supply pipe  35  to stop is outputted to the supply pipe extending/contracting mechanism  38 .  
      Hereinafter, the flow of a process executed in an electrolytic plating apparatus  1  will be explained with reference to  FIG. 12  to  FIG. 14 .  FIG. 12  is a flowchart showing the flow of a process executed in the electrolytic plating apparatus  1  according to this embodiment,  FIG. 13  is a flowchart showing the flow of a plating process in the dummy wafer  200  executed in the electrolytic plating apparatus  1  according to this embodiment, and  FIG. 14  is a view schematically showing the state in the electrolytic plating apparatus  1  according to this embodiment.  
      First, while a gate valve  3  is open, a not-shown carrier arm holding the dummy wafer  200  extends into a holder vessel  5  to carry the dummy wafer  200  into the electrolytic plating apparatus  1  (step  1 C).  
      After the dummy wafer  200  is carried into the electrolytic plating apparatus  1 , the dummy wafer  200  is suction-held by a suction pad  13 . Subsequently, the suction pad  13  moves down to place the dummy wafer  200  on a seal member  12 . Thereafter, a pressing member  14  moves down to press the dummy wafer  200  against the seal member  12 . With this process, the dummy wafer  200  is held by a holder  4  (Step  2 C).  
      After the dummy wafer  200  is held by the holder  4 , the holder vessel  5  moves down to a plating position (IV), so that the dummy wafer  200  is immersed in a plating solution. After the holder vessel  5  is positioned at the plating position (IV), the dummy wafer  200  is plated while the operation of the supply pipe extending/contracting mechanism  38  is being controlled (Step  3 C).  
      Specifically, a voltage is first applied between an anode electrode  24  and cathode electrodes  15  (Step  3 C 1 ). Thereafter, the controller  39  judges, based on the output signals from the ammeters  204 , whether or not the difference between the current passing through the center portion  200 A of the dummy wafer  200  and the current passing through the periphery portion  200 B thereof is within the predetermined range (Step  3 C 2 ); When the difference between the current passing through the center portion  200 A and the current passing through the periphery portion  200 B is not within the predetermined range, it is judged whether or not the current passing through the center portion  200 A is larger than the current passing through the periphery portion  200 B (Step  3 C 3 ). When it is judged that the current passing through the center portion  200 A is larger than the current passing through the periphery portion  200 B, the supply pipe  35  contracts to lower a center facing portion  25 A (Step  3 C 4 ). On the other hand, when it is judged that the current passing through the center portion  200 A is smaller than the current passing through the periphery portion  200 B, the supply pipe  35  extends to lift the center facing portion  25 A (Step  3 C 5 ). Thereafter, the processes from Step  3 C 2  to Step  3 C 5  are repeated until the difference between the current passing through the center portion  200 A and the current passing through the periphery portion  200 B falls within the predetermined range. On the other hand, when the difference between the current passing through the center portion  200 A and the current passing through the periphery portion  200 B is within the predetermined range, the supply pipe  35  is stopped to stop the center facing portion  25 A (Step  3 C 6 ). After the center facing portion  25 A is stopped, the voltage application is stopped (Step  3 C 7 ). With this process, the plating of the dummy wafer  200  is finished.  
      After the plating of the dummy wafer  200  is finished, the holder vessel  5  moves up to a transfer position (I). After the holder vessel  5  is positioned at the transfer position (I), the pressing member  14  moves up to release the pressing to the dummy wafer  200 . Thereafter, the suction pad  13  moves up to have the dummy wafer  200  apart from the seal member  12 . With this process, the holding of the dummy wafer  200  by the holder  4  is released (Step  4   c ).  
      After the holding of the dummy wafer  200  is released, the carrier arm receives the dummy wafer  200 . Thereafter, the carrier arm holding the wafer  100  contracts to carry the dummy wafer  200  out of the electrolytic plating apparatus  1  (Step  5   c ).  
      After the dummy wafer  200  is carried out of the electrolytic plating apparatus  1 , a not-shown carrier arm holding a wafer  100  extends into the holder vessel  5  to carry the wafer  100  into the electrolytic plating apparatus  1  (Step  6   c ).  
      After the wafer  100  is carried into the electrolytic plating apparatus  1 , the wafer  100  is suction-held by the suction pad  13 . Subsequently, the suction pad  13  moves down to place the wafer  100  on the seal member  12 . Thereafter, the pressing member  14  moves down to press the wafer  100  against the seal member  12 . With this process, the wafer  100  is held by the holder  4  (Step  7 C).  
      After the wafer  100  is held by the holder  4 , the holder vessel  5  moves down to the plating position (IV), so that the wafer  100  is immersed in the plating solution. After the holder vessel  5  is positioned at the plating position (IV), the wafer  100  is plated while the center facing portion  25 A is fixed at an adjusted position as shown in  FIG. 14  (Step  8 C).  
      After the plating of the wafer  100  is finished, the holder vessel  5  moves up to a spin-dry position (III). After the holder vessel  5  is positioned at the spin-dry position (III), the holder vessel  5  is rotated in a substantially horizontal plane for spin dry (Step  9 C).  
      After the spin dry is finished, the holder vessel  5  moves up to a cleaning position (II). After the holder vessel  5  is positioned at the cleaning position (II), the holder vessel  5  is rotated in a substantially horizontal plane and pure water is sprayed to the wafer  100  from a washing nozzle  23  to clean the plating applied on the wafer  100  (Step  10   c ).  
      After the plating is cleaned, the holder vessel  5  moves down to the spin-dry position (III). After the holder vessel  5  is positioned at the spin-dry position (III), the holder vessel  5  is rotated in a substantially horizontal plane for spin dry (Step  11 C).  
      After the spin dry is finished, the holder vessel  5  moves up to the transfer position (I). After the holder vessel  5  is positioned at the transfer position (I), the pressing member  14  moves up to release the pressing to the wafer  100 . Thereafter, the suction pad  13  moves up to have the wafer  100  apart from the seal member  12 . With this process, the holding of the wafer  100  by the holder  4  is released (Step  12 C).  
      After the holding of the wafer  100  is released, the carrier arm receives the wafer  100 . Thereafter, the carrier arm holding the wafer  100  contracts to carry the wafer  100  out of the electrolytic plating apparatus. 1  (Step  13 C).  
      It should be noted that the present invention is not to be limited to the contents described in the above embodiments, and appropriate changes in the structure, the materials, the arrangement of each member, and so on may be made within a range not departing from the sprit of the present invention. In the first to third embodiments described above, the supply pipe  35  is extended/contracted to vertically move the center facing portion  25 A, but the vertical movement of the center facing portion  25 A may be made without the extension/contraction of the supply pipe  35 .  
      In the first to third embodiments described above, the periphery facing portion  25 B is not moved and the center facing portion  25 A is moved, but the periphery facing portion  25 B may be moved without moving the center facing portion  25 A. Further, the frame  26  whose center portion is positioned closer to the wafer  100  side than the periphery portion thereof is used, but a flat frame  26  may be used. Note that, when the flat frame  26  is used, the diaphragm  25  is flatly supported.  
      In the first to third embodiments described above, the controller  39  automatically controls the operation of the supply pipe extending/contracting mechanism  38 , but the supply pipe extending/contracting mechanism  38  may be manually controlled. Further, the wafer  100  is used, but a glass substrate may be used.  
     INDUSTRIAL APPLICABILITY  
      A solution treatment apparatus and a solution treatment method according to the present invention are usable in the semiconductor manufacturing industry.