Patent Publication Number: US-2015068890-A1

Title: Substrate plating jig and plating device using same

Description:
TECHNICAL FIELD 
     The present invention relates to a plating jig and a plating device used for substrate plating processing, and more particularly to a plating jig for forming a plating film on a fine wiring groove, a hole, and a resist opening portion formed on a surface to be plated of a semiconductor wafer and the like or for forming a bump (projecting electrode) which electrically connects a semiconductor chip and a substrate to each other on a surface to be plated of a semiconductor wafer, and a plating device which uses the plating jig. 
     BACKGROUND ART 
     In general, an electrolytic plating method is roughly classified into a jet-type or cup-type plating method where plating is performed such that a substrate such as a semiconductor wafer or the like is horizontally placed with a surface to be plated of the substrate facing down, and a plating solution is jetted from below, and a dip-type plating method where plating is performed such that a substrate is vertically disposed in an erected manner in a plating bath, a plating solution is jetted into the plating bath from below the plating bath, the substrate is immersed in the plating solution in the plating bath while allowing the overflow of the plating solution from the plating bath. The reason why plating is performed with the substrate disposed in a vertically erected manner in the dip-type electrolytic plating method is that bubbles generated on the surface to be plated of the substrate can be easily removed and that it is possible to make it difficult for particles or the like adhere to the surface to be plated of the substrate. In this manner, with the use of the electrolytic plating method where plating is performed with the substrate disposed in a vertically erected manner, babbles which are formed by a vigorous reduction action at the time of performing high-speed plating can be easily removed. Accordingly, this electrolytic plating method is desirable. 
     An electrolytic plating device which adopts the above-mentioned conventional dip-type electrolytic plating method includes a substrate holder which holds a substrate such as a semiconductor wafer in a detachable manner in a state where outer peripheral edge surfaces and a back surface of the substrate are sealed and a front surface (a surface to be plated) is exposed, and the surface to be plated of the substrate is plated by immersing the substrate holder into a plating solution together with the substrate. 
     However, in such a conventional electrolytic plating method which adopts dip-type plating, the substrate is immersed while holding the substrate in a vertically erected state in the plating solution, and the plating solution is made to flow in the upward direction from a lower portion of the plating bath. Accordingly, the plating solution jetted into the plating bath is always supplied toward an upper portion from a lower portion of the surface to be plated of the substrate and hence, a flow speed of the plating solution becomes non-uniform between the upper portion and the lower portion of the surface to be plated of the substrate thus giving rise to a drawback that a delicate difference occurs in film thickness of plating depending on a place of the surface to be plated of the substrate. Further, non-uniformity of current density also becomes a factor which causes non uniformity of plating. 
     To overcome such drawbacks, patent literatures 1, 2 disclose a plating method and a plating device where a substrate holder which holds a substrate such as a semiconductor wafer is rotated in a plating bath by a drive unit so that non-uniformity in flow speed or non-uniformity in current density of a plating solution are eliminated whereby the uniformity of a plating film thickness is increased. 
     However, as in the case of a plating method such as the plating method disclosed in patent literature (PTL) 1 where a shaft is connected to the substrate holder in a state where the shaft from the drive unit arranged outside the plating bath penetrates a side wall of the plating bath, sealing treatment of a penetrating portion arises as a problem to be solved. To cope with this drawback, in the method disclosed in PTL 1, sealing treatment is not applied to the penetrating portion intentionally such that the shaft and the side wall of the plating bath are brought into a non-contact state from each other, and a plating solution flows out through a gap formed between the shaft and the side wall. Such constitution, however, requires the modification of the plating bath. On the other hand, in the plating method disclosed in PTL 2, a drive shaft is arranged at a predetermined angle and hence, the drive shaft does not penetrate a side wall of a plating bath. However, it is necessary to modify the plating bath itself eventually including the arrangement of an anode plate at a predetermined angle so as to make an anode plate face an object to be plated or the formation of a bottom portion of the plating bath along an angle of the shaft. 
     LIST OF RELATED ART 
     Patent Literature 
     PTL 1: JP-A-2004-300462 
     PTL 2: JP-A-2002-327291 
     SUMMARY OF INVENTION 
     Technical Problem 
     Accordingly, the present invention has been made to overcome such drawbacks of the conventional plating device, and it is an object of the present invention to provide a plating jig which includes a rotation drive unit for rotatably driving a substrate holder and is detachably mountable on a plating bath without modifying the plating bath, and a plating device which utilizes the plating jig. 
     Solution to Problem 
     The present invention has been made to overcome the above-mentioned drawbacks, and provides a plating jig which is characterized by including: a support portion formed in an engageable manner with a side wall of a plating bath; and a substrate holder mounted on the support portion in a vertically rotatable manner, wherein the plating jig further includes a rotary means for rotating the substrate holder. 
     The present invention also provides a plating device which is characterized in that the plating jig is engageable with the side wall of the plating bath, and a paddle which is movable in a reciprocating manner in the lateral direction is arranged between the substrate holder and an anode plate which faces the substrate holder in an opposed manner. 
     Advantageous Effects of Invention 
     According to the plating jig of the present invention, the plating jig can be easily mounted on the plating device by merely making the plating jig engage with the side wall of the plating bath, a plating solution flow is used as a rotary drive unit for rotating the substrate holder, or power of a drive part is transmitted to the substrate holder by way of a rotary shaft or a gear member. None of these provisions requires the modification of the plating bath. 
     Further, according to the plating device provided with the plating jig of the present invention which is also provided with the paddle for agitation between the substrate holder and the anode plate, a plating solution flow which flows along a surface to be plated of the substrate can be made uniform also by the agitation generated by the paddle in addition to the rotation of the plating jig and hence, it is possible to form a plating film having a more uniform film thickness. 
     In the case where the plating device provided with the plating jig of the present invention is also provided with a plating solution jetting port on a bottom portion of the plating bath disposed below the substrate holder, a rotational force can be generated more efficiently by providing a difference in strength of the plating solution flow between left and right sides of the substrate holder. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  An exploded perspective view of a plating jig of the present invention. 
         FIG. 2  A schematic constitutional view of a plating device on which the plating jig of the present invention is mounted. 
         FIG. 3  ( a ) A side view of an outer frame member of the plating jig of the present invention. 
       ( b ) A front view of the outer frame member of the plating jig of the present invention. 
         FIG. 4  ( a ) A side view of the outer frame member of the plating jig of the present invention. 
       ( b ) A front view of the outer frame member of the plating jig of the present invention. 
         FIG. 5  ( a ) A side view of the outer frame member of the plating jig of the present invention. 
       ( b ) A front view of the outer frame member of the plating jig of the present invention. 
         FIG. 6  ( a ) A view showing a different mode of a blade portion of the outer frame member of the plating jig of the present invention. 
       ( b ) A view showing a different mode of the blade portion of the outer frame member of the plating jig of the present invention. 
         FIG. 7  A schematic constitutional view of the plating device on which the plating jig of the present invention is mounted. 
         FIG. 8  A schematic constitutional view of the plating device on which the plating jig of the present invention is mounted. 
         FIG. 9  A partially enlarged cross-sectional view of a substrate holder in the plating jig of the present invention. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Hereinafter, embodiments of a plating jig of the present invention and a plating device which uses the plating jig are explained in detail by reference to drawings. The present invention is not particularly limited to the embodiments. 
       FIG. 1  is an exploded perspective view of the plating jig of the present invention, and  FIG. 2  is a schematic constitutional view of the plating device on which the plating jig of the present invention is mounted. In the drawings, symbol  1  indicates the plating device, symbol  2  indicates the plating jig, symbol  10  indicates a plating bath, symbol  11  indicates a side wall, symbol  12  indicates a jetting port, symbol  20  indicates an overflow tank, symbol  30  indicates a substrate holder, symbol  31  indicates a holding member, symbol  32  indicates a sealing member, symbol  33  indicates an outer frame member, symbol  34  indicates a shaft portion, symbol  35  indicates a fixing bolt, symbol  36  indicates a fixing bolt, symbol  37  indicates a fixing bolt, symbol  40  indicates a support portion, symbol  41  indicates a hole portion, symbol  50  indicates an anode plate, symbol  60  indicates a paddle, symbol  70  indicates a power source, symbol  71  indicates an electricity supply path, symbol  80  indicates a piping, symbol  81  indicates a pump, symbol  82  indicates a filter, symbol  311  indicates a base portion, symbol  312  indicates a substrate mounting surface, symbol  313  indicates a hole portion, symbol  314  indicates a first electricity supply member, symbol  321  indicates an opening portion, symbol  331  indicates connecting portions, symbol  332  indicates blade portions, and symbol W indicates a substrate respectively. 
     As shown in the drawings, the plating jig  2  of the present invention is constituted of: the support portion  40  which is formed in an engageable manner with the side wall of the plating bath; and the substrate holder  30  which is rotatably mounted on the support portion  40 . The respective portions are explained in detail by reference to  FIG. 1 . The support portion  40  is formed of a columnar-shaped member having an upper portion thereof formed into a hook shape such that the support portion  40  can be engaged with an upper end of the side wall of the plating bath, and the hole portion  41  into which the shaft portion  34  can be inserted is formed in a lower portion of the support portion  40 . The substrate holder  30  having a disc shape is held by the hole portion  41  by way of the shaft portion  34  in a vertically rotatable manner. 
     The substrate holder  30  is constituted of: the holding member  31 ; the sealing member  32 ; the outer frame member  33 ; the shaft portion  34 ; and the fixing bolts  35 ,  36 ,  37 . Among these components, with respect to the holding member  31 , on an upper surface of the base portion  311  formed in a disc shape, the substrate mounting surface  312  having a diameter smaller than a diameter of the base portion  311  is mounted in a projecting manner. The substrate mounting surface  312  has the substantially same shape and size as the substrate W to which plating is applied. A plurality of first electricity supply members  314  are mounted on the base portion  311  around the substrate mounting surface  312  in a projecting manner. Further, the hole portion  313  into which the shaft portion  34  can be inserted is formed in a center portion of the substrate mounting surface  312 . 
     The sealing member  32  is formed into an annular shape having the substantially same diameter as the holding member  31 , and the opening portion  321  of the sealing member  32  is formed with an inner diameter slightly smaller than an outer diameter of the substrate W. On a surface of the sealing member  32  which faces the holding member  31  in an opposed manner, an annular-shaped seal packing  322  and a second electricity supply member  323  (not shown in  FIG. 1 ) are mounted. At the time of assembling the substrate holder  30 , the substrate W is sandwiched between the sealing member  32  and the holding member  31  thus sealing the first electricity supply member  314  on the base portion  311  and supplying electricity to the substrate W. 
     The outer frame member  33  is constituted of two members consisting of semi-annular left and right members. The outer frame member  33  has an approximately U-shaped cross section. At the time of assembling the substrate holder  30 , the outer frame member  33  is fitted on outer peripheral edges of the holding member  31  and the sealing member  32 . To be more specific, two outer frame members  33  are mounted on the outer peripheral edges of the holding member  31  and the sealing member  32  from left and right sides, and the outer frame members  33  are fastened and fixed to each other at upper and lower connecting portions  331  using bolts or the like. In the plating jig  2  shown in  FIG. 1 , the plurality of blade portions  332  are formed on an outer peripheral surface of the outer frame member  33  in a projecting manner. However, as described later, when other rotary means is used, such blade portions  332  are not always necessary. 
     The substrate holder  30  is mounted on the support portion  40  such that the shaft portion  34  having a threaded portion is inserted into the hole portion  313  formed in the holding member  31  and the hole portion  41  formed in the support portion  40 , and the fixing bolts  35 ,  36 ,  37  are threadedly engaged with the threaded portion of the shat portion  34  thus fixing the substrate holder  30  to the support portion  40 . In this case, it is desirable to seal the fixing bolt  36  which are exposed to a plating solution by applying coating or the like to the fixing bolt  36  after the bolt  36  is fixed to the shaft portion  34 . Although the fixing bolt  37  is exposed to the plating solution in the same manner as the fixing bolt  36 , it is desirable to form recessed portions into which the fixing bolt  37  can be embedded on a back surface of the support portion  40  as shown in  FIG. 1 , and to mask an opening portion of the recessed portion using a vinyl chloride plate, a tape or the like. Further, it is also desirable that coating is applied to a portion of the shaft portion  34  which is exposed to the plating solution using Teflon (registered trademark), an epoxy-system resin or the like. 
     Further, a method of mounting the substrate holder  30  on the support portion  40  which differs from the above-mentioned method is explained hereinafter. Firstly, the support portion  40  is formed such that the support portion  40  is split into two parts as viewed from a front side, that is, left and right members, and the recessed portion in which the shaft portion  34  and the fixing bolt  37  can be embedded is formed on the left and right members respectively. Then, the shaft portion  34  on which the fixing bolt  37  is preliminarily mounted is arranged on either one of the left and right members of the support portion  40  having the split structure, and the other member of the support portion  40  is abutted and fixed to one member thus finishing the mounting of the substrate holder  30  on the support portion  40 . Due to such a mounting method, the whole length of the shaft portion  34  can be further shortened and, at the same time, as described above, it is unnecessary to seal the opening portion formed on a back side of the support portion  40 . 
     Next, a method of supplying electricity to the substrate W is explained. An electricity supply path  71  which is embedded into the support portion  40  or drawn into the inside of the support portion  40  from a back surface supplies electricity to the shaft portion  34  via an electricity supply brush (not shown in the drawing) from the external power source  70 . The shaft portion  34  is made of a conductive raw material such as a titanium material, a phosphor bronze material, a pure copper material or the like, and supplies electricity to the fixing bolt  35  which is also made of a conductive raw material. Then, electricity is supplied to the first electricity supply members  314  via an electricity supply paths (not shown in the drawing) which is embedded in the inside of the holding member  31  from the fixing bolts  35 ,  36  provided for fixing the holding member  31 . 
       FIG. 9  is a partially-enlarged view showing a conduction mode in a state where the substrate holder  30  is assembled while sandwiching the substrate W between the sealing member  32  and the holding member  31 . As shown in  FIG. 9 , on a surface of the sealing member  32  which faces the holding member  31  in an opposed manner, the annular seal packing  322  and the second electricity supply member  323  are mounted. The seal packing  322  has a U-shaped cross-sectional shape where a length of an upper and a length of lower side differ from each other. The second electricity supply member  323  is formed into a flat disc shape. A plurality of projecting contact points  324  are formed on an inner periphery of the second electricity supply member  323  in a projecting manner. At the time of assembling the substrate holder  30 , a flat plate portion of the second electricity supply member  323  is brought into contact with the first electricity supply member  314  mounted on the base portion  311 , and the projecting contact points  324  are brought into contact with a plated surface of the substrate W. Due to such a constitution, electricity can be supplied to the substrate W from the first electricity supply member  314  via the second electricity supply member  323 . The above-mentioned conducting method is desirable from a viewpoint that electricity can be surely supplied to the substrate W without exposing the first electricity supply member  314  and the second electricity supply member  323  into the plating solution due to the seal packing  322 . However, a method of supplying electricity to the plating jig of the present invention is not limited to the above-mentioned method. 
     Next, the rotary means for the substrate holder  30  is explained. As the rotary means for the substrate holder  30  in the plating jig  2  of the present invention, a method which makes use of the flow of plating solution by providing blade portions or recessed portions on an outer peripheral surface of the outer frame member or a method which rotates the substrate holder  30  by a drive part can be adopted.  FIG. 3(   a ) and  FIG. 3(   b ) show the constitution where blade portions  332  are formed on the outer peripheral surface of the outer frame member  33  in a projecting manner. As shown in the drawings, with respect to the rotary means of this embodiment, the plurality of blade portions  332  having a rectangular-plate shape are formed on the outer peripheral surface of the outer frame member  33  equidistantly. The blade portion  332  is formed on the outer peripheral surface in an approximately vertically erected manner, and a blade portion is arranged horizontally as viewed in a side view. The rotary means where the blade portions are mounted on the outer frame member  33  can generate a rotational force when a plaiting solution flow impinges on the blade portions  332  so that the substrate holder  30  can be rotated. 
       FIG. 4  ( a ) and  FIG. 4  ( b ) show blade portions  333  formed in a different mode. As shown in the drawings, the blade portions  333  are formed on an outer peripheral surface of the outer frame member  33  in an approximately vertically-erected manner. However, the blade portions  333  are not arranged horizontally but are arranged with an angle such that the blade portions  333  are inclined downwardly from a front side to a rear side. By giving such angle to the blade portions  333  in this manner, the rotary means can catch the flow of plating solution from a front side more effectively. Further, by forming the blade portion into an approximately U shape or an approximately V shape instead of a rectangular plate shape, as shown in  FIG. 6  ( a ) and  FIG. 6  ( b ), the rotary means can catch the flow of plating solution more easily. 
       FIG. 5  ( a ) and  FIG. 5  ( b ) show the rotary means where recessed portions  334  are formed on an outer peripheral surface of an outer frame member  33  in a recessed manner. As shown in the drawings, in this embodiment, the plurality of recessed portions  334  each having a rectangular shape are formed on the outer peripheral surface of the outer frame member  33  equidistantly. In this manner, by forming the recessed portions  334  on the outer peripheral surface of the outer frame member  33 , the recessed portions catch the flow of the plating solution in the same manner as the blade portions and can generate a rotational force so that the substrate holder  30  can be rotated. 
       FIG. 7  shows a first mode of rotating a substrate holder  30  by a drive part. As shown in  FIG. 7 , a rotational force is transmitted to a gear  93  mounted on a shaft portion  34  by way of a shaft  91  from a drive part  90  such as an electrically-operated motor. The gear  34  transmits a rotational force of the shaft  91  to the shaft portion  34  while converting the rotation of the shaft  91  into the rotation of the shaft portion  34 . Accordingly, the substrate holder  30  can be rotated. The drive part  90  may be directly mounted on the support portion  40 , or may be detachably mounted on a mounting portion  92 . An additional support portion may be provided outside a plating bath for supporting the drive part  90 . The transmission of a rotational force to the shaft portion  34  from the drive part  90  may be, besides the transmission using the combination of the shaft and the gear as in the case of this embodiment, the transmission using the combination of a plurality of gear members, or the transmission using a belt. 
       FIG. 8  shows a second mode of rotating a substrate holder  30  by a drive part. As shown in  FIG. 8 , a gear portion  94  is mounted on an upper portion of the substrate holder  30 , and a gear  95  having the same pitch as the gear portion  94  is mounted on an outer frame member of the substrate holder  30 . When a rotational force is transmitted to the gear portion  94  from the drive part  90 , the rotational force is transmitted to the gear  95  mounted on the outer frame member so that the substrate holder  30  can be rotated. The transmission of a rotational force to the gear portion  94  from the drive part  90  may be the transmission using the combination of the shaft and the gear as in the case of the first embodiment, the transmission using the combination of a plurality of gear members or the transmission using a belt. 
     The rotary means for the substrate holder  30  is not limited to either one of the above-mentioned methods, that is, the method which makes use of the flow of plating solution by forming the blade portions or the recessed portions on the outer peripheral surface of the outer frame member  33 , and the method which rotates the substrate holder  30  by the drive part, and the rotary means may be combination of these rotary means. That is, a rotational force may be imparted to the substrate holder  30  by forming the blade portions or the recessed portions on the outer peripheral surface of the outer frame member  33  and, at the same time, a rotational force may be imparted to the substrate holder  30  by using an external drive part. In this manner, with the use of two kinds of different rotational forces, the rotation of the substrate holder  30  can be made further stable thus suppressing the power consumption. 
     Next, a plating device which uses the plating jig  2  of the present invention is explained.  FIG. 2  is a schematic constitutional view of the plating device  1  on which the plating jig  2  of the present invention is mounted. As shown in  FIG. 2 , the plating device  1  of the present invention includes the plating bath  10 , and the overflow tank  20  arranged on an outer periphery of the plating bath  10 . The plating jig  2  is mounted on the side wall  11  of the plating bath  10 . In the inside of the plating bath  10 , the anode plate  50  is arranged at a position facing a plated surface of the substrate W held by the substrate holder  30  in an opposed manner. The paddle  60  may be arranged between the anode plate  50  and the substrate holder  30  as in the case of this embodiment. The paddle  60  can make the flow of plating solution along the plated surface of the substrate uniform by moving in a reciprocating manner parallel to the plated surface of the substrate W. Accordingly, a plating film having a further uniform film thickness can be formed by a synergistic effect brought about by the paddle  60  and the substrate holder  30  having the rotary means. From the above reasons, the provision of the paddle  60  is desirable. 
     A jetting port  12  to which the piping  80  is connected is formed in the bottom portion of the plating bath  10 , and a plating solution is supplied into the inside of the plating bath  10  through the jetting port  12 . When the jig which makes use of the flow of the plating solution by forming the blade portions or the recessed portions on the outer peripheral surface of the outer frame members shown in  FIG. 1  and  FIG. 3  to  FIG. 6  is utilized, it is desirable to arrange the jetting port  12  at a position where the flow of plating solution can effectively transmit a rotational force to the blade portions or the recessed portions of the outer frame member  33 . To be more specific, it is desirable to arrange the jetting port  12  below the substrate holder  30  and along the direction parallel to the substrate holder  30 . In this case, by providing the jetting port  12  to only one side of the plating bath  10  or by making jetting amounts of the plating solution from the jetting ports  12  different from each other between the left and right sides so as to make a strength of the flow of plating solution different between the left and right sides of the substrate holder  30 , a rotational force can be generated more efficiently. Accordingly, it is desirable to adopt such a constitution. 
     REFERENCE SIGNS LIST 
     
         
           1 : plating device 
           2 : plating jig 
           10 : plating bath 
           11 : side wall 
           12 : jetting port 
           20 : overflow tank 
           30 : substrate holder 
           31 : holding member 
           32 : sealing member 
           33 : outer frame member 
           34 : shaft portion 
           35 : fixing bolt 
           36 : fixing bold 
           37 : fixing bolt 
           40 : support portion 
           41 : hole portion 
           50 : anode plate 
           60 : paddle 
           70 : power source 
           71 : electricity supply path 
           80 : piping 
           81 : pump 
           82 : filter 
           90 : drive part 
           91 : shaft 
           92 : mounting portion 
           93 : gear 
           94 : gear portion 
           95 : outer frame member 
           311 : base portion 
           312 : substrate mounting surface 
           313 : hole portion 
           314 : first electricity supply member 
           321 : opening portion 
           322 : seal packing 
           323 : second electricity supply member 
           324 : projecting contact point 
           331 : connection portion 
           332 : blade portion 
           333 : blade portion 
           334 : recessed portion 
         W: substrate