JP2012107267A - Plating apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plating apparatus which forms a plating layer having a uniform thickness on each base material particle having an electroconductive surface in a high yield.SOLUTION: The plating apparatus includes: a plating tank 1j having a plating chamber which is equipped with a bottom surface on which base material particles revolve while being brought into contact with the bottom surface and a peripheral wall surface erected along the peripheral edge of the bottom surface, and accommodates a particle group 9 including the base material particles and a plating solution; a plating solution supply pipe 1e which has a supply port 1f opening at an upper part of the bottom surface of the plating chamber and supplies the plating solution from the supply port so that the plating solution may revolve along the peripheral wall surface of the plating chamber; a plating solution discharge pipe 1c having a discharge port 1d opening in the plating chamber; a cathode 1n which is brought into contact with base material particles being arranged on the bottom surface of the plating chamber 1m; an anode 1o arranged at a position immersed in the plating solution accommodated in the plating chamber; and a power source 1h connected to the cathode and the anode. The discharge port 1d of the plating solution discharge pipe is closed with a plating solution permeable member 4 through which the plating solution permeates but the base material particles do not permeate.

Description

  The present invention relates to a plating apparatus for base particles having conductivity on the surface.

  As an example of a technique for plating base material particles having conductivity on the surface, solder is coated on the surface of a core ball mainly composed of Cu and solder-coated Cu core ball (hereinafter abbreviated as Cu core ball). There is technology to form. In order to clarify the problems of the prior art, the plating technique of the present invention will be described using a Cu core ball as an example, but the present invention is not limited to the Cu core ball.

  In recent semiconductor packages such as BGA (Ball Grid Array) and CSP (Chip Scale Package) where high-density mounting is progressing due to multi-pitch and narrow pitch, small-diameter Cu core balls are adopted as bumps for input / output terminals. . Cu core ball does not melt at the time of reflow, so it can maintain a certain distance between the semiconductor element and the substrate, ensuring connection reliability against thermal cycle load caused by starting and stopping of semiconductor element can do.

  As a Cu core ball manufacturing technique, a barrel electroplating method is known in which a core ball is housed in a barrel having a large number of openings through which a plating solution can flow, and the barrel is placed in a plating bath and rotated to coat the solder. ing. However, particularly when a small-diameter Cu core ball having a diameter of 100 μm or less is manufactured, the core ball is not sufficiently stirred only by the rolling of the core ball accompanying the rotation of the barrel. As a result, the core balls are connected and agglomerated through the plating layer, or the surface of the plating layer is roughened, resulting in a problem that the thickness of the plating layer becomes partially non-uniform and the yield decreases. It was happening.

  An example of a technique for solving the problem of the barrel type electroplating method is described in Patent Document 1. In Patent Document 1, in order to obtain a sufficient and uniform plating layer in a short time, “the object to be plated is placed between the lower surface of the outer peripheral portion of the bottom-opened bowl-shaped resin dome with the upper end open and the upper surface of the outer peripheral portion of the resin bottom plate. A contact ring that is pressed during rotation and a porous ring through which the treatment liquid circulates are integrally combined to form a cell. `` Rotary plating device for small items, fixing the upper end of a vertical conductive drive shaft, pressing a contact brush on the shaft and connecting it to the negative pole, placing an anode basket in the dome, and covering the cell '' Is described. According to the rotary plating apparatus having such a configuration, the object to be plated accommodated in the cell is forcibly pressed against the contact ring by the action of the centrifugal force generated by the rotation of the cell, and the rotation and stop or deceleration of the cell. By repeating the above, it is described that the mixture is uniformly mixed, the plating solution on the surface of the object to be plated is renewed actively, and a plating layer having a uniform thickness can be formed.

  Another technical example for solving the problem of the barrel type electroplating method is described in Patent Document 2. In Patent Document 2, the purpose is to prevent deformation or the like of a workpiece having a particularly easy-to-bend property, and “a plating tank having an upper surface opening and a detachable lid for closing the upper surface opening of the plating tank are provided. And having a cathode on the bottom surface of the plating tank, an anode on the back surface of the detachable lid, and a nozzle for spraying a plating solution directed toward the inner surface of the peripheral wall on the peripheral wall along the bottom surface of the plating tank. A plating apparatus is described. And in patent document 2, by employ | adopting such a structure, the workpiece | work thrown in in the plating tank turns into the inside of a plating tank with the plating liquid injected from an injection nozzle, and a plating process is given accompanying the rotation. For this reason, it is described that there is no collision between workpieces that cause bending or deformation, and the plating process can be completed while all the workpieces retain their original shapes.

JP-A-8-239799 Japanese Utility Model Publication No. 7-6267

  The present invention has been made in view of the above prior art, and an object of the present invention is to provide a plating apparatus capable of forming a plating layer having a uniform thickness on a surface of conductive substrate particles with a high yield. Yes.

  A plating apparatus according to the present invention for solving the above-mentioned problems is a plating apparatus for base particles having conductivity on the surface, and is erected along the bottom surface that can be circulated while the base material particles are in contact with the periphery of the bottom surface. A plating tank having a plating chamber that can store a particle group including the base material particles and a plating solution, and a supply port that opens upward from the bottom surface of the plating chamber. A plating solution supply pipe for supplying a plating solution from the supply port so as to swirl along the wall surface; a plating solution discharge pipe having a discharge port opened to the plating chamber; and the base material disposed on the bottom surface of the plating chamber. A cathode in contact with the particles; an anode disposed at a position immersed in a plating solution housed in the plating chamber; and a power source connected to the cathode and the anode; The plating solution is permeated Particles are plating apparatus is closed by the plating liquid passage member which does not transmit.

  In such a plating apparatus, the bottom surface of the plating chamber has a circular shape, the peripheral wall surface of the plating chamber has a truncated cone shape with a diameter reduced toward the bottom surface of the plating chamber, and the plating solution discharge pipe has an axis of the truncated cone shape. It is preferable to be arranged coaxially with the core, and a more remarkable effect can be achieved by using a plating apparatus in which the discharge port is disposed below the supply port.

  Furthermore, it is preferable that the plating solution permeable member for closing the plating solution discharge port has a contact surface with which the base particle contacts, and the contact surface has at least an inclined surface that is not perpendicular to the axis of the plating solution discharge pipe.

  Such a plating apparatus has the following effects. That is, the plating solution supplied from the supply port of the plating solution supply pipe flows down toward the bottom surface while turning along the peripheral wall surface of the plating chamber. Then, when the plating chamber is filled with the plating solution, it is discharged from the plating solution discharge pipe through the discharge port opened to the plating chamber, and the plating chamber is always kept fresh by supplying new plating solution from the plating solution supply pipe. Filled with.

  The swirling and flowing plating solution that has reached the bottom surface of the plating chamber causes the particle group stored in the plating chamber to swirl while contacting the bottom surface of the plating chamber. The base material particles in contact with the cathode on the bottom surface are subjected to a plating treatment with an anode disposed at a position immersed in the plating solution, and a plating layer is formed on the surface of the base material particles. The particles are swirling on the bottom surface while rolling while contacting the bottom surface while being mixed with each other without being dispersed by the swirling flowing plating solution. Evenly, each of the parts touches the plating solution, and as a result, a plating layer having a uniform thickness is formed. In addition, the particle | grains which started the turning motion will continue a turning motion, repeating intermittent contact with the bottom face, without floating. Furthermore, since the substrate particles roll while being in contact with the bottom surface of the plating chamber due to the swirling flow of the plating solution, the substrate particles are more likely to come into contact with other substrate particles, and thus the substrate particles in contact with the cathode It is electrically connected with high frequency, and it is possible to perform a process close to continuous plating, and it is possible to efficiently form a plating layer on the base particles, and further, a plating layer formed by contact between the base particles Is smoothed to form a plating layer having a very smooth surface and a uniform thickness.

  Here, there is a possibility that the base material particles swirling around the bottom surface of the plating chamber ride on the flow of the plating solution toward the plating solution discharge pipe, leave the bottom surface, and flow out of the plating solution discharge tube together with the plating solution. However, the discharge port of the plating solution discharge pipe is blocked by a plating solution permeable member that allows the plating solution to permeate but does not allow the base material particles to penetrate. Therefore, the plating solution permeable member obstructs the discharge of the plating solution from the plating chamber. Without causing the base particles to flow out. The base material particles that have been prevented from flowing out by the plating solution permeable member are captured by the swirling flow along the peripheral wall surface of the plating chamber and transported again to the bottom surface of the plating chamber, where the plating process is performed. Thus, by providing the plating solution permeable member, the base material particles can be prevented from flowing out of the plating chamber, and the base material particles can be plated with a high yield.

  As described above, according to the plating apparatus according to the present invention, the object of the present invention is to provide a plating apparatus capable of forming a plating layer having a uniform thickness on a surface of conductive substrate particles with high yield. Can be achieved. In addition, the preferable aspect and effect of the said plating apparatus are demonstrated in detail below.

It is a figure which shows schematic structure of the plating apparatus of one embodiment concerning this invention. It is a top view of the plating apparatus of FIG. 1 and the plating apparatus of the preferable aspect. It is the elements on larger scale of the plating apparatus of FIG. 1, and the plating apparatus of the preferable aspect.

  Hereinafter, a plating apparatus according to the present invention will be described based on its embodiments with reference to the drawings. In the following embodiment, a description will be given of a plating apparatus that coats the surface of a spherical core ball mainly composed of Cu, which is a base particle, with a plating layer mainly composed of Sn, but the present invention is limited to this. Without forming the metal coating layer on the surface of the resin or ceramic particles or other conductive particles on the surface by electroless plating, for example, electroless plating or other conductive metal layer such as nickel It can also be applied to. Further, the present invention can be applied not only to spherical base particles such as a core ball, but also to, for example, needle-like base particles having a major axis and a minor axis, and amorphous base particles having no shape characteristics. Furthermore, each component of the plating apparatus described below can be used alone or in appropriate combination.

  As shown in the front view of FIG. 1 which is a schematic configuration of the plating apparatus and the plan view of FIG. 2A in which the sealing lid 1L of FIG. 1 is removed, the plating apparatus 1 includes a main body 1a, plating A plating solution circulation means 1b and a DC power supply circuit 1h, which are connected to the main body 1a via a solution supply pipe 1e and a plating solution discharge pipe 1c, are provided as a basic configuration.

  In the main body 1a, reference numeral 1j denotes a plating tank in which a plating chamber 1m having a circular bottom surface 1p and a frustoconical peripheral wall surface 1q having a diameter reduced toward the bottom surface 1p is formed. A plating tank 1j made of a resin or the like, which is a non-conductive insulator having corrosion resistance to the plating solution, is closely attached to a bowl-shaped container 1k having an upper opening and an upper surface of the container 1k so as to close the upper opening. And a sealed lid 1L. A space formed by the container 1k and the sealing lid 1L constitutes a plating chamber 1m, and a ball group (particle group) 9 including a large number of core balls 91 and a predetermined amount of plating solution L are stored in the plating chamber 1m. The The bottom surface and the peripheral wall surface constituting the plating chamber are not limited to the above configuration, and the bottom surface only needs to have a shape that allows the core ball to circulate while being in contact with the core ball, and the peripheral wall surface is the bottom surface. As long as the plating chamber can be formed together with the bottom surface, it is sufficient.

  The plating solution supply pipe 1e is horizontally connected at one end thereof to the plating tank 1j so that the axis of the plating solution extends along the tangential direction of the peripheral wall 1q of the plating chamber 1m, and the plating solution supply port 1f opens above the plating chamber 1m. One end of the plating solution discharge pipe 1c is connected to the plating tank 1j so that the plating solution discharge port 1d opens in the plating chamber 1m coaxially with the axial center of the plating chamber 1m at the center of the sealing lid 1L. Is connected to the plating solution circulating means 1b. By disposing the plating solution discharge pipe 1c coaxially with the axial center of the plating chamber 1m, the influence on the swirling flow a can be suppressed, and the swirling motion of the core ball 91 on the bottom surface 1p can be stabilized. In addition, the plating solution supply pipe 1e is connected to the plating solution supply port 1f by opening the plating solution supply port 1f so that one end thereof is not horizontal with respect to the plating tank 1j but at a certain angle so that the swirling flow a is formed. May be. Further, if the plating solution L overflowing from the plating chamber 1m is simply discharged, the plating solution discharge pipe 1c may be disposed on the outer periphery of the sealing lid 1L.

  The plating solution discharge pipe 1c of this embodiment is disposed so as to pass through the central portion of the sealing lid 1L and protrude into the plating chamber 1m, and the plating solution discharge port 1d is in the middle of the plating chamber 1m in the axial direction. In this embodiment, the plating solution discharge pipe 1c can be moved along the axial direction as indicated by an arrow d. According to the plating apparatus 1 provided with such a plating solution discharge pipe 1c, the plating solution discharge port 1d is close to the bottom surface 1p of the plating chamber 1m, so that the upward flow b of the plating solution L is discharged near the bottom surface 1p. The influence of the upward flow b on the swirling flow a is suppressed, and the swirling motion of the core ball 91 on the bottom surface 1p can be stabilized. The plating solution discharge pipe 1c may be a pipe having an outer wall that does not hinder the flow of the swirling flow a and an inner wall that does not hinder the flow of the upward flow b, but is preferably a cylindrical pipe.

  The plating solution circulation means 1b includes a plating solution storage tank, a plating solution circulation pump, a plating solution purification filter, a flow rate control valve, and the like (not shown). The plating solution L sent from the plating solution circulation means 1b is: It flows through the plating solution supply pipe 1e and is supplied from the plating solution supply port 1f to the plating chamber 1m, and forms a swirling flow a indicated by a broken line in FIGS. 1 and 2A to form the circumferential wall 1q of the plating chamber 1m. Down the river. Further, the flow rate and flow rate of the plating solution L supplied to the plating chamber 1m can be changed with time by adjusting the plating solution circulation pump and the flow rate control valve of the plating solution circulation means 1b. A plurality of the plating solution supply pipes 1e may be provided. In this case, the plating solution supply pipes may be arranged on the same circumference of the peripheral wall surface 1q of the plating chamber 1m so that, for example, a plurality of plating solution supply ports 1f are opened at a constant angular pitch, and the swirling flow a is formed. The plating solution supply pipe 1e may be arranged so that a plurality of plating solution supply ports 1f are opened along the flow of the plating solution L flowing down. With the above configuration, as shown in FIG. 1, the plating solution L spirally flows along the circumferential wall 1q inclined downward and flows down spirally to reach the bottom surface 1p of the plating chamber 1m. As shown in the figure, the flow increases, and is discharged from the plating solution discharge pipe 1c through the plating solution discharge port 1d and returns to the plating solution circulation means 1b.

  Here, the plating solution transmitting member which is one of the features of the present invention will be described with reference to FIG. 1 and FIG. 3A which is a partially enlarged sectional view of FIG. The plate-like plating solution transmitting member 3 fixed to the lower bottom surface of the plating solution discharge pipe 1c and closing the discharge port 1d transmits the plating solution L and does not transmit the core ball 91. It is formed by a mesh-like nonconductive filter having a small gap. The mesh shape of the filter can be square, hexagonal, polygonal, circular, or the like, and can be fixed directly to the plating solution discharge pipe 1c with an adhesive, or the plating solution can be discharged through a member. It may be fitted and fixed to the tube 1c. As shown in FIG. 3A, the plating solution permeable member 3 allows the plating solution to pass therethrough and smoothly discharges the plating solution L from the plating chamber 1m through the plating solution discharge pipe 1c. At the bottom surface, which is the contact surface 3a, the flow of the core ball 91a which is trapped by the rising plating solution flow b and flows out of the plating solution discharge pipe 1c is prevented. As the plating solution permeable member 3, a filter made of a metal, resin, ceramics or other material having a predetermined gap through which the core ball 91 does not pass can be used. In addition, if a honeycomb-shaped filter having voids arranged substantially linearly is used as the plating solution permeable member 3, the flow resistance when the plating solution passes through the plating solution permeable member 3 is reduced, and the plating solution can be smoothly discharged. This is preferable.

  The core ball 91a whose movement is prevented by the ball contact surface (bottom surface) 3a of the plating solution permeable member 3 is a flow in which the upward flow b of the plating solution collides with the ball contact surface 3a and changes its direction in the lateral direction ( It is pushed by the arrow c) and moves toward the peripheral wall 1q of the plating chamber 1m while being in contact with the contact surface 3a. The core ball 91b that has moved to the side of the peripheral wall surface 1q is captured by the swirling flow a of the plating solution L flowing along the peripheral wall surface 1q of the plating chamber 1m, is carried to the bottom surface 1p, and is again plated. Therefore, the ball contact surface 3a is a smooth surface or a surface on which a radial pattern is formed toward the outer periphery of the ball contact surface 3a so that the movement of the core ball 91a on the ball contact surface 3a is not hindered. It is preferable. The cross-sectional view of the ball contact surface 3a is not necessarily linear, and may be a curved cross-section that bulges toward the bottom.

  A preferred embodiment of the plating solution permeable member will be described with reference to FIGS. 3 (b) to (e), the plating solution transmitting members 4 to 7 have their ball contact surfaces 4a to 7a extending from the center 4b to 7b of the plating solution discharge port 1d toward the peripheral wall surface 1q in the horizontal plane. And it is common in the point which has the inclined surfaces 4c-7c which are not perpendicular | vertical to the axial center of a plating solution discharge pipe opposite to the surrounding wall surface 1q. First, the plating solution permeable member 4 will be described. In each figure, the same components as those in FIG. 3A are denoted by the same reference numerals, and detailed description thereof will be omitted.

  As shown in FIG. 3 (b), the plating liquid permeable member 4 of the first preferred embodiment has a substantially umbrella shape with a sharp tip at the center facing the bottom surface 1p side of the plating chamber 1m, and has a tip in a horizontal plane. The sharp portion is fixed to the bottom surface of the plating solution discharge pipe 1c with an adhesive so as to close the plating solution discharge port 1d at the center of the plating solution discharge port 1d. In the plating solution permeable member 4 of this aspect, a cone extending from the center 4b of the plating solution discharge port 1d toward the entire circumference of the peripheral wall surface 1q at an equal angle and facing the peripheral wall surface 1q in the bottom surface, that is, in a horizontal plane. The ball contact surface 4a having a shape is an inclined surface 4c whose entire surface is not perpendicular to the axis of the plating solution discharge pipe.

  The plating solution permeable member 4 having such an inclined surface 4c has the following preferable effects. That is, the core ball 91 a that is captured by the rising flow b of the plating solution and faces the plating solution discharge pipe 1 c is prevented from flowing at the contact surface 4 a of the plating solution transmitting member 4. The core ball 91 whose movement is blocked by the ball contact surface 4a is pushed by a flow (see arrow d in the drawing) in which the upward flow b of the plating solution collides with the inclined surface 4c and changes its direction along the inclination of the inclined surface 4c. While moving in the direction of the peripheral wall 1q of the plating chamber 1m while in contact with the inclined surface 4c, the movement of the core ball 91 at this time is quicker than in the case of using the plating transmission member 3 of FIG. Move. The core ball 91b that has moved to the side of the peripheral wall surface 1q is captured by the swirling flow a of the plating solution L flowing along the peripheral wall surface 1q of the plating chamber 1m, is carried to the bottom surface 1p, and is again plated. In the plating solution permeable member 4 of this aspect, since all of the ball contact surface 4a is configured to be the inclined surface 4c, the core ball 91a can be captured at any location on the ball contact surface 4a. The effect which it did can be show | played.

  The inclined surface is not limited to the inclined surface 4c of the plating solution permeable member 4 and the inclined surface 5c of the plating solution permeable member 5 shown in FIG. It may be an inclined surface constituted by a curved line, and there is no problem even if the flat surface 5d is formed at the center and the inclined surface 5c extends from the outer peripheral edge 5b of the flat surface 5d.

  In FIG. 1, reference numeral 1n denotes a disk-like cathode disposed at the bottom of the container 1k, and the upper surface of the cathode 1n is configured to be the bottom surface 1p of the plating chamber 1m. The cathode 1n connected to the negative electrode of the DC power supply circuit 1h is made of, for example, stainless steel, titanium, platinum-plated titanium, or the like. The ball group 9 is swung by the plating liquid L swirling in the plating chamber 1m while being in contact with the bottom surface 1p in a predetermined range in the radial direction from the outer peripheral end, as indicated by reference numeral C in the figure. The ball 91 rolls on the bottom surface 1p while being stirred.

  Although the cathode may be arranged so as to be in contact with only a part of the many core balls 91 arranged on the bottom surface 1p, the core ball 91 not in direct contact with the cathode is energized through the core ball 91 in contact with the cathode. Therefore, the potential of the core ball 91 at a position away from the cathode due to the contact resistance between the core balls 91 is lowered, the current density in the core ball 91 is lowered, and the plating efficiency may be lowered. Therefore, when viewed in a plan view, as shown in FIG. 2A, the cathode preferably has a sufficient contact area with the ball group 9, and is formed in a disk shape as in this embodiment. Is preferred. In this case, the container 1k itself may be formed of a cathode material, and the inner surface of the container 1k may be coated with a corrosion-resistant and insulating resin coating so that the bottom surface of the container 1k acts as the cathode 1n.

  On the other hand, as shown in FIGS. 1 and 2 (a), when all of the bottom surface 1p of the plating chamber 1m is constituted by the cathode 1n, the formation rate of the plating layer may be lowered. That is, since the ball group 9 swirls in a predetermined region C on the outer peripheral edge of the bottom surface 1p (the upper surface of the cathode 1n) with the plating solution L that swirls and flows, the central portion of the upper surface of the cathode 1n without the ball group 9 exists. This is also because the plating is deposited in vain. Therefore, as shown by reference numeral 2n in FIG. 2B and FIG. 2C, which is a cross-sectional view along the center line thereof, the cathode corresponds to the region in which the ball group 9 swivels and is located on the outer periphery of the bottom surface 2p. It is preferably provided in an annular shape, and the central portion 2z of the bottom surface 2p is preferably made of an electrically insulating material. In the case of FIGS. 2B and 2C, the central portion 2z is integrally formed with the container 1k. For example, the central portion 2z is formed separately from insulating ceramics and incorporated into the container 1k. You may do it.

  Furthermore, as shown in FIG. 2 (c), the cathode 2n is not only the first cathode 2y exposed so that its surface forms the same plane as the bottom surface 2p, but also its inner surface is the same as the peripheral wall 1q. You may equip the base end part of the container 1k with the 2nd cathode 2x exposed so that a surrounding surface may be formed. As shown in the figure, the cathodes 2x and 2y can be incorporated into the container 1k as a cathode 2n coupled at one end so as to have a cross-sectional cross section. By providing the second cathode 2x, the area of the cathode 2n with which the ball group 9 can contact can be increased, and a uniform plating layer can be formed on the core ball 91 while maintaining high plating efficiency. Is possible. In order to prevent the deposition of plating on the surface of the cathode 2n and increase the plating efficiency, the cathode 2n is included in the range C in which the ball group 9 swirls as shown in FIG. Is preferred. Further, the cathode 2n shown in FIG. 2 (b) is formed in a continuous annular shape in the circumferential direction, but if it is formed in a substantially annular shape even if there is a discontinuous portion in part. good.

  In FIG. 1, reference numeral 1o denotes an anode containing tin disposed on the outer peripheral surface of the plating solution discharge pipe 1c so as to face the cathode 1n. The anode 1o is fixed to the hermetic lid 1L via a support member such as stainless steel, titanium, platinum-plated titanium or the like so as to be positioned at a position where the anode 1o is immersed in the plating solution L that fills the plating chamber 1m. Connected to the positive electrode.

  The operation of the plating apparatus 1 will be described with reference to FIGS. 1 and 3 (a). First, it is a preparation process. In the preparation step, the sealing lid 1L is opened, a predetermined number of core balls 91 are placed on the bottom surface 1p of the plating chamber 1m (the top surface of the cathode 1n), and the plating solution L is stored in the plating solution storage tank of the plating solution circulation means 1b. To do. In addition, as the core ball 91, a pickled surface cleaned surface may be used, and if necessary, a surface in which a nickel plating layer is formed as a base layer may be used. The plating solution for solder plating is, for example, the trade name “DAIN TINSIL SBB 2” manufactured by Daiwa Kasei Co., Ltd. having a Sn—Ag—Cu based liquid composition, the product name “SOLDERON BP SAC5000” manufactured by Rohm & Haas, etc. Additives can be added to a known plating bath such as a borofluoride bath, for example, and used as appropriate. The particles constituting the ball group 9 are not limited to the core ball 91. For example, as a stirring accelerator for promoting the stirring of the ball group 9, for example, conductive dummy balls mainly made of solder or steel, resin, ceramics, etc. An appropriate amount of a non-conductive dummy ball as a main component may be added.

  After closing the sealing lid 1L and making the plating chamber 1m into a sealed space, the plating apparatus 1 is operated. The plating apparatus 1 operates the plating solution circulating means 1b to supply the plating solution L at a predetermined flow rate to the plating chamber 1m through the plating solution supply pipe 1e. When the plating chamber 1m is filled with the plating solution L, the plating solution L turns along the peripheral wall surface 1q of the plating chamber 1m and turns into a swirling flow a that flows spirally along the inclination of the peripheral wall surface 1q toward the bottom surface 1p. . In addition, since the flow of the plating solution L is unstable at the initial stage of the supply of the plating solution L, the core ball 91 may flow out of the plating chamber 1m due to the unstable flow of the plating solution L. Since the plating apparatus 1 is provided with the plating solution permeable member 3, the outflow at this initial stage can be prevented.

  The plating liquid L swirling down the plating chamber 1m along the circumferential wall surface 1q of the plating chamber 1m having a truncated cone shape which is reduced in diameter toward the bottom increases in swirling speed as it approaches the bottom surface 1p and reaches the bottom surface 1p. The swirl flow a of the plating solution L that has reached the bottom surface 1p causes the ball group 9 in contact with the bottom surface 1p to swivel while pressing against the bottom surface 1p. Here, since the core ball 91 included in the ball group 9 is in contact with the bottom surface 1p, that is, the upper surface of the cathode 1n connected to the negative electrode of the DC power supply circuit 1h, the core ball 91 is plated with the anode 1o, A plating layer is formed on the surface. Since the plating solution L that has reached the bottom surface 1p of the plating chamber 1m becomes an upward flow b at the center of the bottom surface 1p and is discharged from the plating solution discharge pipe 1c through the plating solution discharge port 1d and returns to the plating solution circulation means 1b. The fresh plating solution L is supplied to the plating chamber 1m, and the state of the plating solution L in the plating chamber 1m can always be kept constant. As a result, a plating layer having a uniform thickness is formed on the surface of the core ball 91. The

  Here, the plating solution permeable member 3 closing the discharge port 1d of the plating solution discharge pipe 1c transmits the plating solution L but does not transmit the core ball 91. Therefore, as shown in FIG. The plating solution L is smoothly discharged from the plating chamber 1m through the discharge pipe 1c, and the flow of the core ball 91a that is about to flow out of the plating solution discharge pipe 1c is blocked by the ball contact surface 3a. The core ball 91a blocked by the ball contact surface 3a is pushed by the plating solution flow c along the ball contact surface 3a and moves toward the peripheral wall surface 1q of the plating chamber 1m. The core ball 91b that has moved to the side of the peripheral wall surface 1q is captured by the swirling flow a of the plating solution L flowing along the peripheral wall surface 1q of the plating chamber 1m, and is carried to the bottom surface 1p to be plated. Thereby, the outflow from the plating chamber 1m of the thrown core ball 91 is suppressed, and the Cu core ball in which the core ball 91 is plated can be obtained with high yield.

  In addition, since the core ball 91 that rotates while contacting the bottom surface 1p of the plating chamber 1m rolls on the bottom surface 1p and collides so that the core balls 91 rub against each other, the core balls 91 hardly adhere to each other. Aggregation of the core ball 91 is prevented, and the chance of the surface of the core ball 91 touching the bottom surface 1p due to rolling becomes uniform, so that a plating layer having a uniform thickness is formed. Further, the core ball 91 is sufficiently rolled and collided so that the core balls 91 rub against each other, whereby another plated core layer 91 formed on a part of the surface of the core ball 91 is rolled. This prevents the plating layer from being selectively formed on a part of the surface by rubbing and spreading the surface to prevent the plating layer from being selectively formed. The surface is extremely smooth and has few voids inside the plating layer. A plating layer having a uniform thickness can be formed. The plating apparatus of the present invention is an apparatus suitable for forming a plating layer on a core ball having a small diameter of 100 μm or less. The small diameter Cu core ball manufactured by such an apparatus has a smooth plating layer and extremely high sphericity. Particularly suitable as a connecting member for flip chip.

DESCRIPTION OF SYMBOLS 1: Plating apparatus 1a: Main-body part 1b: Plating liquid circulation means 1c: Plating liquid discharge pipe 1d: Plating liquid discharge port 1e: Plating liquid supply pipe 1f: Plating liquid supply port 1h: DC power supply circuit 1j: Plating tank 1k: Container 1L: Sealing lid 1m: Plating chamber 1n (2n): Cathode 1o: Anode 1p (2p): Bottom 1q: Peripheral wall surface 3, 4, 5: Plating solution permeable member 3a, 4a, 5a: Contact surface 4c, 5c: Inclined Surface 9: Ball group (particle group)
91: Core ball (base particle)
a: swirl flow b: upward flow L: plating solution

Claims (4)

  A device for plating base material particles having conductivity on the surface, the base particle comprising a bottom surface capable of rotating while contacting with the base material particle, and a peripheral wall surface erected along the periphery of the bottom surface. A plating tank having a plating chamber capable of storing a group and a plating solution; a supply port that opens upward from the bottom surface of the plating chamber; and a plating solution from the supply port so as to turn along the peripheral wall surface of the plating chamber. A plating solution supply pipe for supplying the plating solution, a plating solution discharge pipe having a discharge opening that opens into the plating chamber, a cathode that contacts the base material particles disposed on the bottom surface of the plating chamber, and is accommodated in the plating chamber. An anode disposed at a position to be immersed in the plating solution, and the cathode and a power source connected to the anode, and the discharge port of the plating solution discharge pipe transmits the plating solution but does not transmit the substrate particles. Clogged with plating solution permeable member Plating apparatus.   The bottom surface of the plating chamber has a circular shape, and the peripheral wall surface of the plating chamber has a truncated cone shape with a diameter reduced toward the bottom surface of the plating chamber, and the plating solution discharge pipe is coaxial with the axis of the truncated cone shape. The plating apparatus according to claim 1, which is arranged.   The plating apparatus according to claim 2, wherein the discharge port is disposed below the supply port. The plating solution permeable member has a contact surface with which the substrate particles come into contact, and the contact surface has at least an inclined surface that is not perpendicular to the axis of the plating solution discharge pipe. The plating apparatus as described.

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