Patent Publication Number: US-2023151507-A1

Title: Plating apparatus

Description:
TECHNICAL FIELD 
     The present invention relates to a plating apparatus. 
     BACKGROUND ART 
     Conventionally, there has been known what is called a cup type plating apparatus as a plating apparatus that can perform a plating process on a substrate (for example, see PTL 1). Such a plating apparatus includes a plating tank that accumulates a plating solution and includes an anode arranged therein, a substrate holder that is arranged above the anode and holds a substrate as a cathode, and a rotation mechanism that is arranged above the substrate holder and rotates the substrate holder. Further, such a rotation mechanism has a rotation shaft connected to the substrate holder and a bearing pivotally supporting this rotation shaft. 
     CITATION LIST 
     Patent Literature 
     PTL 1: Japanese Unexamined Patent Application Publication No. 2008-19496 
     SUMMARY OF INVENTION 
     Technical Problem 
     In the conventional plating apparatus as described above, in a case where particles, such as dirt, generated at the bearing of the rotation mechanism drop, the dropped particles possibly invade the plating tank. 
     The present invention has been made in view of the above, and one of the objects of the present invention is to provide a technique that ensures suppressed invasion of particles generated at a bearing of a rotation mechanism into a plating tank. 
     Solution to Problem 
     [Aspect 1] To achieve the above-described object, a plating apparatus according to one aspect of the present invention includes a plating tank, a substrate holder, a rotation mechanism, and a labyrinth seal member. The plating tank is configured to accumulate a plating solution and include an anode arranged inside the plating tank. The substrate holder is arranged above the anode and configured to hold a substrate as a cathode. The rotation mechanism is arranged above the substrate holder. The rotation mechanism includes a rotation shaft for connecting to the substrate holder and a bearing pivotally supporting the rotation shaft. The labyrinth seal member includes an inner labyrinth seal, an outer labyrinth seal, a delivery port, and a suction port. The inner labyrinth seal is arranged below the bearing to seal the bearing. The outer labyrinth seal is arranged outside in a radial direction of the rotation shaft with respect to the inner labyrinth seal. The delivery port is configured to supply air to an inner seal space formed inside in the radial direction with respect to the inner labyrinth seal. The suction port is configured to suction air in an outer seal space formed outside in the radial direction with respect to the inner labyrinth seal and inside in the radial direction with respect to the outer labyrinth seal. 
     With this aspect, even in a case where particles, such as dirt, generated at the bearing of the rotation mechanism drop into the inner seal space of the labyrinth seal member, together with the air supplied into the inner seal space, the particles can be made to pass through the inner labyrinth seal and be discharged into the outer seal space, and the particles discharged into the outer seal space can be suctioned from the suction port. This can suppress invasion of the particles generated at the bearing of the rotation mechanism into the plating tank, 
     [Aspect 2] In Aspect 1 described above, the labyrinth seal member further includes an upper plate and a lower plate arranged below the upper plate, the inner labyrinth seal and the outer labyrinth seal are arranged so as to be sandwiched between the upper plate and the lower plate, and the delivery port and the suction port are disposed in the upper plate. 
     [Aspect 3] In Aspect 2 described above, the rotation mechanism includes an outer cylindrical member arranged outside in the radial direction of the bearing, the outer cylindrical member is configured not to rotate even in a case where the rotation shaft rotates, and the upper plate is connected to a lower end of the outer cylindrical member, and the lower plate is connected to the rotation shaft. 
     With this aspect, since the outer cylindrical member does not rotate even when the rotation shaft rotates, the upper plate does not rotate either. Then, since the delivery port and the suction port are disposed in the upper plate that does not rotate, a structure of the labyrinth seal member can be simplified, compared with, for example, a case where the delivery port and the suction port are disposed in the lower plate. 
     [Aspect 4] In any one of Aspects 1 to 3 described above, the plating apparatus further includes a control module configured to perform control processing of supplying air from the delivery port and suctioning air from the suction port at least in a case where the rotation mechanism rotates the rotation shaft. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG.  1    is a perspective view illustrating an overall configuration of a plating apparatus of this embodiment. 
         FIG.  2    is a plan view illustrating the overall configuration of the plating apparatus of this embodiment. 
         FIG.  3    is a schematic diagram for describing a configuration of a plating module in the plating apparatus of this embodiment. 
         FIG.  4    is a schematic diagram for describing a configuration of a rotation mechanism and a labyrinth seal member of this embodiment. 
         FIG.  5 A  is an enlarged cross-sectional view of an A 2  part of  FIG.  4   . 
         FIG.  5 B  is an enlarged cross-sectional view of an A 3  part of  FIG.  4   . 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     The following will describe an embodiment of the present invention with reference to the drawings. Note that, in the following embodiment, identical reference signs are assigned for identical or corresponding configurations, and their descriptions may be appropriately omitted. Further, the drawings are schematically illustrated to facilitate understanding of the features of objects, and dimensional proportions and the like of each constituent element are not necessarily the same as the actual ones. Further, in some drawings, orthogonal coordinates of X-Y-Z are illustrated for reference. Of the orthogonal coordinates, the Z direction corresponds to an upper side, and the −Z direction corresponds to a lower side (direction in which gravity acts). 
       FIG.  1    is a perspective view illustrating the overall configuration of a plating apparatus  1000  of this embodiment.  FIG.  2    is a plan view illustrating the overall configuration of the plating apparatus  1000  of this embodiment. As illustrated in  FIGS.  1  and  2   , the plating apparatus  1000  includes load ports  100 , a transfer robot  110 , aligners  120 , pre-wet modules  200 , pre-soak modules  300 , plating modules  400 , cleaning modules  500 , spin rinse dryers  600 , a transfer device  700 , and a control module  800 . 
     The load port  100  is a module for loading a substrate housed in a cassette, such as a FOUP, (not illustrated) to the plating apparatus  1000  and unloading the substrate from the plating apparatus  1000  to the cassette. While the four load ports  100  are arranged in the horizontal direction in this embodiment, the number of load ports  100  and arrangement of the load ports  100  are arbitrary. The transfer robot  110  is a robot for transferring the substrate that is configured to grip or release the substrate between the load port  100 , the aligner  120 , and the transfer device  700 . The transfer robot  110  and the transfer device  700  can perform delivery and receipt of the substrate via a temporary placement table (not illustrated) to grip or release the substrate between the transfer robot  110  and the transfer device  700 . 
     The aligner  120  is a module for adjusting a position of an orientation flat, a notch, and the like of the substrate in a predetermined direction. While the two aligners  120  are disposed to be arranged in the horizontal direction in this embodiment, the number of aligners  120  and arrangement of the aligners  120  are arbitrary. The pre-wet module  200  wets a surface to be plated of the substrate before a plating process with a process liquid, such as pure water or deaerated water, to replace air inside a pattern formed on the surface of the substrate with the process liquid. The pre-wet module  200  is configured to perform a pre-wet process to facilitate supplying the plating solution to the inside of the pattern by replacing the process liquid inside the pattern with a plating solution during plating, While the two pre-wet modules  200  are disposed to be arranged in the vertical direction in this embodiment, the number of pre-wet modules  200  and arrangement of the pre-wet modules  200  are arbitrary. 
     For example, the pre-soak module  300  is configured to remove an oxidized film having a large electrical resistance present on a surface of a seed layer formed on the surface to be plated of the substrate before the plating process by etching with a process liquid, such as sulfuric acid and hydrochloric acid, and perform a pre-soak process that cleans or activates a surface of a plating base layer. While the two pre-soak modules  300  are disposed to be arranged in the vertical direction in this embodiment, the number of pre-soak modules  300  and arrangement of the pre-soak modules  300  are arbitrary. The plating module  400  performs the plating process on the substrate. There are two sets of the 12 plating modules  400  arranged by three in the vertical direction and by four in the horizontal direction, and the total 24 plating modules  400  are disposed in this embodiment, but the number of plating modules  400  and arrangement of the plating modules  400  are arbitrary. 
     The cleaning module  500  is configured to perform a cleaning process on the substrate to remove the plating solution or the like left on the substrate after the plating process. While the two cleaning modules  500  are disposed to be arranged in the vertical direction in this embodiment, the number of cleaning modules  500  and arrangement of the cleaning modules  500  are arbitrary. The spin rinse dryer  600  is a module for rotating the substrate after the cleaning process at high speed and drying the substrate. While the two spin rinse dryers  600  are disposed to be arranged in the vertical direction in this embodiment, the number of spin rinse dryers  600  and arrangement of the spin rinse dryers  600  are arbitrary. The transfer device  700  is a device for transferring the substrate between the plurality of modules inside the plating apparatus  1000 . The control module  800  is configured to control the plurality of modules in the plating apparatus  1000  and can be configured of, for example, a general computer including input/output interfaces with an operator or a dedicated computer. 
     An example of a sequence of the plating processes by the plating apparatus  1000  will be described. First, the substrate housed in the cassette is loaded on the load port  100 . Subsequently, the transfer robot  110  grips the substrate from the cassette at the load port  100  and transfers the substrate to the aligners  120 . The aligner  120  adjusts the position of the orientation flat, the notch, or the like of the substrate in the predetermined direction. The transfer robot  110  grips or releases the substrate whose direction is adjusted with the aligners  120  to the transfer device  700 . 
     The transfer device  700  transfers the substrate received from the transfer robot  110  to the pre-wet module  200 . The pre-wet module  200  performs the pre-wet process on the substrate. The transfer device  700  transfers the substrate on which the pre-wet process has been performed to the pre-soak module  300 . The pre-soak module  300  performs the pre-soak process on the substrate. The transfer device  700  transfers the substrate on which the pre-soak process has been performed to the plating module  400 . The plating module  400  performs the plating process on the substrate. 
     The transfer device  700  transfers the substrate on which the plating process has been performed to the cleaning module  500 . The cleaning module  500  performs the cleaning process on the substrate. The transfer device  700  transfers the substrate on which the cleaning process has been performed to the spin rinse dryer  600 . The spin rinse dryer  600  performs the drying process on the substrate. The transfer device  700  grips or releases the substrate on which the drying process has been performed to the transfer robot  110 . The transfer robot  110  transfers the substrate received from the transfer device  700  to the cassette at the load port  100 . Finally, the cassette housing the substrate is unloaded from the load port  100 . 
     Note that the configuration of the plating apparatus  1000  described in  FIG.  1    and  FIG.  2    is merely an example, and the configuration of the plating apparatus  1000  is not limited to the configuration in  FIG.  1    and  FIG.  2   . 
     Subsequently, the plating modules  400  will be described. Since the plurality of plating modules  400  included in the plating apparatus  1000  according to this embodiment have the identical configuration, one of the plating modules  400  will be described. 
       FIG.  3    is a schematic diagram for describing the configuration of the plating module  400  according to this embodiment. The plating apparatus  1000  according to this embodiment is a cup type plating apparatus. The plating module  400  mainly includes a plating tank  10 , a substrate holder  20 . a rotation mechanism  30 , an elevating mechanism  40 , and a labyrinth seal member  50 . Note that, in  FIG.  3   , cross sections of the plating tank  10 , the substrate holder  20 , and the rotation mechanism  30  are schematically illustrated. 
     The plating tank  10  according to this embodiment is configured of a container with a bottom having an opening on an upper side. Specifically, the plating tank  10  has a bottom portion  10   a  and an outer peripheral portion  10   b  extending upward from an outer peripheral edge of the bottom portion  10   a , and an upper portion of the outer peripheral portion  10   b  is open. Note that, although the shape of the outer peripheral portion  10   b  of the plating tank  10  is not particularly limited, the outer peripheral portion  10   b  according to this embodiment has a cylindrical shape as an example. 
     In an inside of the plating tank  10 , a plating solution Ps is accumulated. It is only necessary for the plating solution Ps to be a solution including an ion of a metallic element constituting a plating film, and a specific example of the plating solution Ps is not particularly limited. In this embodiment, a copper plating process is used as an example of the plating process, and a copper sulfate solution is used as an example of the plating solution Ps. Further, in this embodiment, a predetermined additive is included in the plating solution Ps. However, the configuration of the plating solution Ps is not limited to this, and the plating solution Ps can be configured not to include an additive. 
     In the inside of the plating solution Ps in the plating tank  10 . an anode  11  is arranged. The specific type of the anode  11  is not particularly limited, and a soluble anode or an insoluble anode can be used. In this embodiment, the insoluble anode is used as the anode  11 . The specific type of the insoluble anode is not particularly limited, and platinum, iridium oxide, and the like can be used. 
     The substrate holder  20  is a member for holding a substrate Wf as a cathode. Note that, a lower surface Wfa of the substrate Wf corresponds to a surface to be plated. The substrate holder  20  is connected to a rotation shaft  32  of the rotation mechanism  30 . 
     The rotation mechanism  30  is arranged above the substrate holder  20 . The rotation mechanism  30  is a mechanism for rotating the substrate holder  20 . Details of the rotation mechanism  30  will be described below. 
     The elevating mechanism  40  is supported by a spindle  45  extending in a vertical direction. The elevating mechanism  40  is a mechanism for moving up and down the substrate holder  20  and the rotation mechanism  30  in the vertical direction. As the elevating mechanism  40 . a known elevating mechanism, such as a linear motion type actuator, can be used. 
     When the plating process is performed, the rotation mechanism  30  rotates the substrate holder  20  while the elevating mechanism  40  moves the substrate holder  20  downward to immerse the substrate Wf in the plating solution Ps in the plating tank  10 . After the substrate Wf is immersed in the plating solution Ps, a current flows between the anode  11  and the substrate Wf by an energization device (not illustrated). This forms the plating film on the lower surface Wfa of the substrate Wf. 
     The operation of the plating module  400  is controlled by the control module  800 . The control module  800  includes a microcomputer, and the microcomputer includes a CPU (Central Processing Unit)  801  as a processor, a storage device  802  as a non-transitory storage medium, and the like. The control module  800  controls devices to be controlled of the plating module  400  by an operation of the CPU  801  based on a command of a program stored in the storage device  802 . Further, the control module  800  according to this embodiment also controls an air supply device  70  described later. 
       FIG.  4    is a schematic diagram for describing a configuration of the rotation mechanism  30  and the labyrinth seal member  50 . Specifically,  FIG.  4    illustrates an enlarged cross section of an A1 part of  FIG.  3   . With reference to  FIG.  3    and  FIG.  4   , the rotation mechanism  30  includes a rotation drive device  31 , the rotation shaft  32 , bearings  33 , and an outer cylindrical member  34 . 
     As illustrated in  FIG.  3   , the rotation shaft  32  has an upper end connected to the rotation drive device  31 , and the rotation shaft  32  has a lower end connected to the substrate holder  20 . The rotation drive device  31  is configured of a known rotation drive device, such as a motor, The rotation drive device  31  rotates the rotation shaft  32 , and thus the substrate holder  20  connected to the rotation shaft  32  rotates. 
     With reference to  FIG.  4   , although the specific configuration of the rotation shaft  32  is not particularly limited, the rotation shaft  32  according to this embodiment includes a large-diameter portion  32   a  having a relatively large diameter and a small-diameter portion  32   b  having a relatively small diameter, as an example. The small-diameter portion  32   b  is connected to a lower end of the large-diameter portion  32   a.    
     The bearings  33  are members for pivotally supporting the rotation shaft  32 . The bearings  33  according to this embodiment are arranged outside in a radial direction of the large-diameter portion  32   a  of the rotation shaft  32 . The outer cylindrical member  34  is arranged outside in a radial direction of the bearings  33  (radial direction of the rotation shaft  32 ). That is, the bearings  33  according to this embodiment are sandwiched between the rotation shaft  32  and the outer cylindrical member  34 . 
     The number of the bearings  33  according to this embodiment is plural as an example. Specifically, the rotation mechanism  30  has the bearing  33  arranged on an upper stage side and the bearing  33  arranged on a lower stage side. However, the number of the bearings  33  is not limited to this, and the number of the bearings  33  may be more than two pieces or may be one piece. Although the type of the bearing  33  is not particularly limited, a bearing (rolling bearing) is used as an example in this embodiment. 
       FIG.  5 A  is an enlarged cross-sectional view of an A2 part of  FIG.  4   , and  FIG.  5 B  is an enlarged cross-sectional view of an A3 part of  FIG.  4   . With reference to  FIG.  4   ,  FIG.  5 A  and  FIG.  5 B , the labyrinth seal member  50  includes an upper plate  51 , a lower plate  52 , an inner labyrinth seal  53 , and an outer labyrinth seal  54 . 
     The upper plate  51  is connected to a lower end of the outer cylindrical member  34 , Since the outer cylindrical member  34  does not rotate in a case where the rotation shaft  32  rotates, the upper plate  51  connected. to the outer cylindrical member  34  does not rotate either. The lower plate  52  is arranged below the upper plate  51  and connected to the small-diameter portion  32   b  of the rotation shaft  32 . In a case where the rotation shaft  32  rotates, the lower plate  52  rotates together with the rotation shaft  32 . The inner labyrinth seal  53  and the outer labyrinth seal  54  are arranged so as to be sandwiched between the upper plate  51  and the lower plate  52 . 
     The inner labyrinth seal  53  is arranged below the bearings  33  of the rotation mechanism  30  and disposed for sealing the bearings  33 . As illustrated in  FIG.  5 A  and  FIG.  5 B , the inner labyrinth seal  53  according to this embodiment includes an upper side seal member  53   a  connected to a lower surface of the upper plate  51  and a lower side seal member  53   b  connected to an upper surface of the lower plate  52 . By the upper side seal member  53   a  and the lower side seal member  53   b , a labyrinth seal structure is formed, in a region inside in the radial direction with respect to the inner labyrinth seal  53 , an inner seal space  60  is formed. 
     The outer labyrinth seal  54  is arranged outside in the radial direction with respect to the inner labyrinth seal  53 . Specifically, the outer labyrinth seal  54  includes an upper side seal member  54   a  connected to the lower surface of the upper plate  51  and a lower side seal member  54   b  connected to the upper surface of the lower plate  52 . By the upper side seal member  54   a  and the lower side seal member  54   b , a labyrinth seal structure is formed. With this, in a region outside in the radial direction with respect to the inner labyrinth seal  53  and inside in the radial direction with respect to the outer labyrinth seal  54 , an outer seal space  65  is formed. 
     Further, the labyrinth seal member  50  includes a delivery port  55  configured to supply air (Ar 1 ) to the inner seal space  60  and a suction port  56  configured to suction air (Ar 2 ) in the outer seal space  65 . Specifically, the delivery port  55  and the suction port  56  according to this embodiment are disposed in the upper plate  51 . 
     With this configuration, since the delivery port  55  and the suction port  56  are disposed in the upper plate  51  that does not rotate, a structure of the labyrinth seal member  50  can be simplified, compared with, for example, a case where the delivery port  55  and the suction port  56  are disposed in the lower plate  52  (which rotates together with the rotation shaft  32 ). 
     Note that, while one piece each of the delivery port  55  and the suction port  56  are disposed in this embodiment, the numbers of the delivery port  55  and the suction port  56  are not limited to this. To give another example, the number of the delivery port  55  may be plural. Similarly, the number of the suction port  56  may also be plural. 
     With reference to  FIG.  4   , the delivery port  55  is communicated with the air supply device  70  via a supply flow passage  71 . The air supply device  70  is a device for supplying the air (Ar 1 ) to the delivery port  55 . The air (Ar 1 ) supplied from the air supply device  70  flows through the supply flow passage  71 , and then, the air (Ar 1 ) is delivered out from the delivery port  55  and flows into the inner seal space  60 . Note that, in this embodiment, the air supply device  70  is not a part of the constituent elements of the plating apparatus  1000 . Specifically, in this embodiment, as the air supply device  70 , an air supply device included in plant equipment in which the plating apparatus  1000  is installed (that is, an existing air supply device in the plant equipment) is used. 
     The air (Ar 1 ) that has flowed into the inner seal space  60  can leak from a gap (minute gap) between the upper side seal member  53   a  and the lower side seal member  53   b  of the inner labyrinth seal  53  and flow into the outer seal space  65 . 
     Note that, in this embodiment, as an example of the air (Ar 1 ) supplied from the air supply device  70  to the delivery port  55 , clean air that does not include particles having a particle size of 0.1 μm or more is used. 
     The suction port  56  is communicated with an exhaust air flow passage  81 . In this embodiment, an upstream-side end portion in an air flow direction of the exhaust air flow passage  81  is communicated with the suction port  56 , and a downstream-side end portion of the exhaust air flow passage  81  is arranged at a predetermined position in an outside of the plating tank  10 . This allows the air (Ar 2 ) suctioned from the suction port  56  to pass through the exhaust air flow passage  81  and to be discharged to the predetermined position in the outside of the plating tank  10 . Note that this predetermined position is preferably a position other than an upper side of the plating solution Ps in the plating tank  10 . This is because, with this configuration, even in a case where the particles contained in the air that has passed through the exhaust air flow passage  81  drop, the invasion of the particles in the inside of the plating solution Ps in the plating tank  10  can be surely suppressed. Further, similarly to this embodiment, as long as the air is supplied from the air supply device  70  to the delivery port  55  even when an air exhausting device, such as an exhaust air pump, is not arranged in the exhaust air flow passage  81 , the air in the outer seal space  65  can be suctioned from the suction port  56  by utilizing a pressure difference between the outer seal space  65  and atmospheric air. 
     Further, the control module  800  according to this embodiment is configured to perform control processing of supplying the air to the delivery port  55  and suctioning the air from the suction port  56  at least in a case where the rotation mechanism  30  rotates the rotation shaft  32  (that is, in a case where the substrate holder  20  rotates). 
     Specifically, at least in a case where rotation of the rotation shaft  32  of the rotation mechanism  30  starts, the control module  800  according to this embodiment starts an air supply from the air supply device  70 . At least while the rotation of the rotation shaft  32  is being performed, the control module  800  continues the air supply from the air supply device  70 . With this, at least while the rotation shaft  32  of the rotation mechanism  30  is rotating, the air supply to the delivery port  55  is performed and an air suction from the suction port  56  is performed. 
     With this embodiment as described above, even in a case where the particles, such as dirt, generated at the bearings  33  of the rotation mechanism  30  drop into the inner seal space  60  of the labyrinth seal member  50 , together with the air supplied into the inner seal space  60 , the particles can be made to pass through the inner labyrinth seal  53  (made to pass through the minute gap of the inner labyrinth seal  53 ) and be discharged into the outer seal space  65 , and the particles discharged into the outer seal space  65  can be suctioned from the suction port  56 . This can suppress the invasion of the particles generated at the bearings  33  of the rotation mechanism  30  into the plating tank  10 . 
     Further, with this embodiment, an internal pressure of the inner seal space  60  can be made higher than an atmospheric pressure by supplying the air from the delivery port  55  to the inner seal space  60 . This can effectively suppress invasion of acidic vapor generated from the plating solution Ps in the plating tank  10  into the inner seal space  60 . As a result, corroding the hearings  33  of the rotation mechanism  30  by the acidic vapor can be effectively suppressed. 
     Although the embodiment of the present invention has been described in detail above, the present invention is not limited to such specific embodiment, and further various kinds of variants and modifications are possible within the scope of the gist of the present invention described in the claims. 
     For example, the labyrinth seal member  50  is not limited to that exemplified in  FIG.  4   . To give another example, for example, the plating apparatus  1000  may include a plurality of labyrinth seal members  50  as exemplified in  FIG.  4   . Specifically, in this case, the plurality of labyrinth seal members  50  may be arranged on a plurality of stages in an axial direction (in the vertical direction) of the rotation shaft  32 . 
     REFERENCE SIGNS LIST 
       10  . . . plating tank 
       11  . . . anode 
       20  . . . substrate holder 
       30  . . . rotation mechanism 
       32  . . . rotation shaft 
       33  . . . bearing 
       34  . . . outer cylindrical member 
       50  . . . labyrinth seal member 
       51  . . . upper plate 
       52  . . . lower plate 
       53  . . . inner labyrinth seal 
       54  . . . outer labyrinth seal 
       55  . . . delivery port 
       56  . . . suction port 
       60  . . . inner seal space 
       65  . . . outer seal space 
       70  . . . air supply device 
       400  . . . plating module 
       1000  . . . plating apparatus 
     Wf . . . substrate 
     Wfa . . . lower surface 
     Ps . . . plating solution 
     Ar 1 , Ar 2  . . . air