JP6607001B2 - Plating apparatus and plating method - Google Patents

Description

  The present invention relates to a plating apparatus and a plating method, and more particularly, to a plating apparatus and a plating method used when plating an object to be plated such as a chip-type electronic component.

  For example, in an electronic component such as a chip-type multilayer capacitor, Ni plating or Sn is applied to the surface of an external electrode included in the electronic component for the purpose of preventing solder erosion or improving mounting reliability by soldering. Plating is generally performed.

  When such an electronic component is subjected to plating such as Ni plating or Sn plating, it is often performed by a barrel plating method as disclosed in Patent Document 1.

  When performing barrel plating, the cathode terminal is disposed in the barrel so as to be in contact with the group of objects to be plated in the barrel so that the object to be plated becomes a cathode, and is immersed in a plating solution outside the barrel. The object to be plated is plated by arranging an anode terminal and applying current to both the electrodes to energize.

JP-A-10-212596

  However, in the above conventional barrel plating method, when the object to be plated is reduced in size, the object to be plated floats in the plating solution, or the barrel is provided with a lid for taking in and out the object to be plated, and the rotating shaft portion. In some cases, an object to be plated is sandwiched in the gap, and a good plating film cannot be formed.

  Furthermore, the plating film formed by the barrel plating method is formed by energization when the conductive medium and the object to be plated are in contact with each other. The plating film formed at various current densities with variations can be obtained. Since the films are stacked, the uniformity of the film thickness of the plating film is lowered, and the stress tends to increase as the plating film. And there exists a problem that the fall of the adhesiveness with the base | substrate of to-be-plated object and the mechanical strength of to-be-plated object may be caused.

  In the case of barrel plating, if the local high current density region exceeds the limit current density of the plating bath, the deposition efficiency of the plating metal is reduced and hydrogen gas is generated. It is necessary to perform plating while keeping the density low, and the amount of current that can be supplied to the entire system is restricted, which may hinder the improvement of production.

  The present invention solves the above-described problem, and a plating apparatus and a plating method capable of surely passing an object to be plated through a plating region and performing plating at a uniform current density. The purpose is to provide.

In order to solve the above problems, the plating method of the present invention is:
(A) a separation unit that separates a mixed fluid containing a plating solution and an object to be plated into the plating solution and an object concentrate that contains the object to be plated at a higher solid content concentration than before separation;
(B) a plating part that is located below the separation part and that performs electrolytic plating on the object to be plated when passing the object concentrate to be plated separated by the separation part;
A plating solution holding area for holding the plating solution;
An anode disposed so as to be at least partially immersed in the plating solution;
At least a part is surrounded by a partition wall that allows the plating solution to pass therethrough but does not allow the plating object to pass therethrough, and a plating object passage region that allows the plating object concentrate to pass from above to below,
A plating portion comprising: a cathode disposed in the plating object passage region so as to come into contact with the plating object passing through the plating object passage region;
(C) The object to be plated is attracted from the lower end of the plating object passage area by the suction force generated by flowing the plating solution separated in the separation part, and the object to be plated is concentrated. The object to be plated is dispersed in the flowing plating solution and supplied to the separation part, and the object to be plated is attracted and loosened.

Further, in the plating apparatus of the present invention, the cathode is disposed along the axial direction so as to pass through the center of the plating object passage region, and the partition wall is disposed concentrically with the cathode. Is preferred.

By the above-described configuration, it is possible to move the object to be plated, Ri smoothly good, it is possible to perform a stable plating.

  In addition, the cathode is disposed along the axial direction so as to pass through the center of the plating object passage region, and the cathode is disposed outside the plating object passage region so as to surround the plating object passage region. The anode is disposed concentrically with the cathode, and the plating object passes through a region between the outer peripheral surface of the cathode and the inner peripheral surface of the plating object passage region. Is preferred.

  With the above configuration, the uniformity of the current density distribution is increased due to the arrangement of the anode and the cathode, and it becomes possible to form a uniform and good plating film by reducing the variation in current density during plating. .

  Moreover, it is preferable that it is a liquid cyclone which has a shape where the said separation part tapers toward the said plating part located below.

  With the above configuration, the mixed fluid containing the plating solution and the object to be plated is surely separated into the plating solution and the object concentrate containing the object to be plated at a higher solid content concentration than before separation. It is possible to make the present invention more effective.

  Moreover, it is preferable that the horizontal cross-sectional area of the upper end part of the said plating part which is a connection part with the lower end part of the said separation part is larger than the horizontal cross-sectional area of the lower end part of the said separation part.

  By adopting the above configuration, it is possible to prevent the object concentrate from the separation part from being caught and smoothly flowing when moving to the object passage region of the plating part, and the separation part. It is possible to supply the stable plating object concentrate in which the plating object is uniformly deposited to the plating portion by suppressing the influence of the liquid flow on the plating passing area.

  Moreover, it is preferable that the said to-be-plated material attracting / relaxing part is an ejector or an injector configured to generate a suction force using the plating solution as a fluid.

  By adopting the above-described configuration, it becomes possible to efficiently attract the object to be plated from the area through which the object is to be plated, to the object to be plated / unraveling part, and to disperse it in the plating solution. It can be tightened.

Moreover, the plating apparatus of the present invention comprises:
The cathode has a tubular shape that penetrates the separation part and the central part of the plating part in the axial direction and reaches the object to be plated attracting and loosening part,
The plating solution separated by the separation portion passes through the inside of the tubular cathode from the top to the bottom, and is sucked from the lower end, thereby attracting from the lower end portion of the plating object passage region. It is preferable that the object to be plated concentrate is attracted.

  By adopting the above configuration, it is possible to reliably attract the concentrated object to be plated that has passed through the plating part to the attracting and unraveling part of the object and disperse it in the plating solution with a simple structure. It is possible to provide a plating apparatus capable of applying the above. In the case of this configuration, the region where the plating solution at the lower end of the cathode is discharged functions as an object to be plated attracting / relaxing portion.

Moreover, the plating method of the present invention comprises:
(A) separating the mixed fluid containing the plating solution and the object to be plated into the plating solution and the object to be plated containing the object to be plated at a higher solid content concentration than before separation;
(B) At least a part of the cylindrical object to be plated passing region in which the cathode is disposed along the axial direction in the center surrounded by a partition wall that allows the plating solution to pass but not the object to be plated; An object to be plated is made to pass through the object to be plated passing from above to below in a plating part having an anode arranged concentrically with the cathode on the outside of the diaphragm. Performing electrolytic plating on
(C) By the suction force generated by flowing the plating solution separated in the separating step , the object to be plated is attracted from the lower end of the object passage region, and the object to be plated is And a step of dispersing in the flowing plating solution.

  Moreover, in the plating method of this invention, it is preferable to perform the electroplating to the said to-be-plated object by repeating the process of said (a), (b), (c).

  By setting it as the said structure, the plating film of sufficient film thickness can be formed in a to-be-plated thing.

  Moreover, in the plating method of this invention, it is preferable to pass the said to-be-plated object through the said to-be-plated object passage area | region at the speed | rate of 0.1-30 cm / sec.

  With the above-described configuration, it is possible to ensure an appropriate plating time and perform highly reliable plating.

Since the plating method of the present invention includes the separation part, the plating part, and the object to be plated attracting / unraveling part configured as described above, the object to be plated is an area where the plating should be reliably performed. It is possible to perform good plating with a stable current density by passing through the plating portion. As a result, it is possible to reliably form a stable plating film in which the stress of the plating film is small and the plating film thickness variation is small.
The plating apparatus of the present invention may allow the object to be plated and the conductive medium to coexist when performing plating, and can also perform plating only with the object to be plated without coexisting the conductive medium. is there.

The plating method of the present invention includes (a) a step of separating a mixed fluid containing a plating solution and an object to be plated into a plating solution and an object to be plated containing the object to be plated at a high solid content concentration, (B) The plating solution of the plating part that allows the plating solution to pass through but does not pass the object of plating to pass through the plated object concentrate surrounded by the partition; and (c) the plating solution separated in the separating step A step of attracting the object to be plated from the lower end portion of the region to be plated and dispersing the object to be plated in the plating solution by the suction force generated by flowing the Since the electroplating is performed on the object to be plated by sequentially repeating the above, the object to be plated is passed through the plating portion, which is the area where the plating should be surely performed, and good plating is performed with a stable current density. Can be .

It is front sectional drawing which shows the structure of the plating apparatus concerning Embodiment 1 of this invention. It is a plane sectional view showing the plating apparatus concerning Embodiment 1 of the present invention. It is front sectional drawing which shows the principal part structure of the plating apparatus concerning Embodiment 1 of this invention. It is front sectional drawing which shows the structure of the plating apparatus concerning Embodiment 2 of this invention. It is a plane sectional view showing the plating apparatus concerning Embodiment 2 of the present invention. It is front sectional drawing which shows the principal part structure of the plating apparatus concerning Embodiment 2 of this invention.

  In the following, embodiments of the present invention will be shown to describe the features of the present invention in more detail.

[Embodiment 1]
In the first embodiment, a plating apparatus used when a multilayer ceramic capacitor, which is a typical chip-type electronic component, is an object to be plated and an external electrode formed on the surface is subjected to electrolytic plating will be described as an example.
FIG. 1 is a front sectional view showing a plating apparatus A according to Embodiment 1 of the present invention, and FIG. 2 is a plan sectional view. FIG. 3 is an enlarged front cross-sectional view showing the main configuration.

As shown in FIGS. 1-3, this plating apparatus A is
(A) The mixed fluid 10 containing the plating solution 11 and the object to be plated 12 is separated into the plating solution 11 and the object to be plated concentrate 13 containing the object to be plated 12 at a higher solid content concentration than before separation. Separation unit 1;
(B) A plating part provided with an anode 21 and a cathode 22, which is located below the separation part 1 and performs electroplating on the object to be plated 12 when passing the object concentrate 13 separated by the separation part 1. 2,
(C) Inducing the object to be plated after loosening the object to be plated 13 after plating and dispersing the object 12 to be plated contained in the object to be plated 13 in the plating solution 11 and supplying it to the separation unit 1・ Equipped with a loosening part 3.

  Further, the plating apparatus A includes a power source 31 for energizing the anode 21 and the cathode 22, and circulates and supplies the plating solution 11 separated by the separation unit 1 to the object to be plated attracting / relaxing unit 3. A circulation line 32, a plating solution tank 33 disposed in the circulation line 32, and a pump 34 provided on the downstream side of the plating solution tank 33 of the supply line 32.

  And as the separation part 1 of said (a), the liquid cyclone 1a which has a tapering shape toward the lower plating part 2 is used.

  The liquid cyclone 1a is provided with a supply port 50 through which the mixed fluid 10 of the plating solution 11 and the object to be plated 12 is swung along the inner wall, and a vortex finder 51 at the center of the upper portion and discharged at the upper portion thereof. A chamber 52 is provided, and a discharge port 53 to the outside is provided at a position off the central axis of the discharge chamber 52.

  By configuring the liquid cyclone 1a in this way, even if an air column is generated in the cyclone at the start of operation, the air column is disturbed in the upper discharge chamber, and the generated bubbles are discharged out of the system. It is possible to quickly eliminate the air column that is in the air. As a result, for example, when plating is performed using a plating bath containing a plating metal that is easily oxidized such as Sn, it is possible to prevent the plating metal from being oxidized by air and extend the life of the plating bath. become.

  Further, the plating part 2 of (b) includes a plating solution holding region 20 that holds the plating solution 11, an anode 21 that is disposed so that at least a part thereof is immersed in the plating solution 11, and at least a part thereof. The plating solution 11 is allowed to pass but the plating object 12 is not allowed to pass through, and is surrounded by the partition wall 25, and the plating object passage region 23 through which the plating object concentrate 13 passes from above to below, and the plating object passage region 23. A cathode 22 made of a rod-shaped electrode material is provided in the plating object passage region 23 so as to come into contact with the plating object 12 passing therethrough.

  The anode 21 is annular in plan view, and is disposed concentrically with the cathode 22 so as to surround the plating object passage region 23 at a predetermined interval from the plating object passage region 23. In this plating apparatus A, as described above, the region between the inner peripheral surface of the partition wall 25 and the outer peripheral surface of the cathode 22 that constitutes the plating object passage region 23 concentrically surrounded by the anode 21 is the surface to be coated. Since it is configured to be a region through which the plated product concentrate 13 (the material to be plated 12) passes, that is, the material to be plated passing region 23, a uniform plating film can be obtained by reducing variations in current density during plating. Can be formed.

Moreover, among the partition 25 which comprises the to-be-plated object passage area | region 23, the upper part of the to-be-plated object passage area | region 23 is comprised so that it may not have liquid permeability. Thus, by making the area | region which comprises the upper part of the to-be-plated object passage area | region 23 of the partition 25 not to have liquid permeability, the liquid cyclone 1a in the upper part of the to-be-plated object passage area | region 23 of The influence of the liquid flow is suppressed, and the plating object 12 contained in the plating object concentrate 13 can be stably passed through the plating object passage region 23 while being smoothly deposited.

  Furthermore, for the purpose of uniforming the surface current density distribution of the diaphragm in the area where the electrolytic plating is performed, the partition walls constituting the plating object passage area 23 so as to surround the upper part and the lower part of the plating object passage area 23 An upper mask member 24a and a lower mask member 24b are disposed outside the 25 with a predetermined interval.

  In addition, the object to be plated attracting / relaxing part 3 of (c) is to be plated from the lower end part of the object passing area 23 by the suction force generated by flowing the plating solution 11 separated by the separating part 1. The product concentrate 13 is attracted, and the product 12 contained in the product concentrate 13 can be dispersed in the plating solution 11 and supplied to the separation unit 1.

  And this to-be-plated object attracting / unwinding part 3 is set as the structure provided with the taper-shaped part 3a tapering toward the lower end following the to-be-plated object passage area | region 23, and the ejector 40. As shown in FIG. In addition, the lower end side of the tapered portion 3 a is connected to the throat portion 40 a of the ejector 40.

  That is, in this plating apparatus A, the plating solution 11 separated in the liquid cyclone 1a of the separation unit 1 is supplied from one end side of the ejector 40 through the plating solution tank 33 and the pump 34, and passes through the throat portion 40a at high speed. Due to the suction force generated by this, the object concentrate 13 is attracted from the lower end of the object passage region 23 through the tapered portion 3a and the throat part 40a of the ejector 40, and the object concentrate 13 is attracted. The object 12 to be plated is dispersed in the plating solution 11 and returned to the separation unit 1 via the circulation line 32.

  Moreover, in the plating apparatus A of this Embodiment 1, it passes through the to-be-plated object passage area | region 23 of the plating part 2 from the isolation | separation part 1, and the middle part of the to-be-plated material attracting / unraveling part 3 (area | region before the ejector 40) ) Is configured as a concentric space. Therefore, the object 12 to be plated is prevented from being caught by a structure or the like inside the apparatus on the way from the separation part 1 to the object to be plated attracting / unwinding part 3 through the plating part passing region 23. Thus, it can be moved smoothly, and stable electrolytic plating can be performed.

  In the region between the height position of the cathode 22 corresponding to the lower end of the upper mask member 24a and the height position corresponding to the upper end of the lower mask member 24b, the outer peripheral surface is made conductive. For the region above the height position corresponding to the lower end of the upper mask member 24a and the region below the height position corresponding to the upper end of the lower mask member 24b, the upper insulating material 22a and the lower insulation Since it is made to coat | cover with the material 22b, it becomes possible to equalize the current density in the area | region where plating is performed, and favorable plating can be performed reliably.

  Next, a method for plating the object to be plated 12 using the plating apparatus A of Embodiment 1 configured as described above will be described.

In the plating method of the present invention, the plating is
(A) a step of separating the mixed fluid 10 including the plating solution 11 and the workpiece 12 into the plating solution 11 and the plating object concentrate 13;
(B) a step of performing electroplating on the object to be plated 12 by passing the object-to-be-plated concentrate 13 from above to below the plating object passage region 23 of the plating unit 2;
(C) The attracting force generated by flowing the plating solution 11 attracts the object to be plated 13 from the lower end portion of the object passage region 23, loosens the object to be plated 12, and disperses in the plating solution 11. The steps of supplying the separation unit 1 to the separation unit 1 are repeated in order.

  First, the separation step (a) is a step of separating the mixed fluid 10 into a plating solution 11 and an object concentrate 13 in the separation unit 1, and the object 12 to be plated is separated by the liquid cyclone 1a. The material 12 is separated and moves downward from the lower part of the hydrocyclone 1a to the material passing region 23 of the plating unit 2 while being concentrated and deposited.

Further, in the plating step (b) described above, by passing the material to be plated 13 from the power supply 31 to the anode 21 and the cathode 22 and passing the material to be plated passing region 23 from the upper side to the lower side, The plating is performed.

  Then, in the step (c), the object 12 to be plated is unraveled in the object attracting / relaxing part 3, and the object to be plated 12 is separated in the liquid 11 to be plated. Returned to part 1.

  On the other hand, the plating solution 11 separated from the object to be plated 12 by the liquid cyclone 1 a of the separation unit 1 is recovered and returns to the plating solution tank 33 through the circulation line 32.

Then, the plating solution 11 that has returned to the plating solution tank 33 is supplied to the ejector 40 via the circulation line 32.
Then, the plating solution 11 is supplied from one end side of the ejector 40 and attracted from the lower end portion of the plating object passage region 23 by the suction force generated when passing through the throat portion 40a at high speed (deposits). ) 13 is attracted to the object to be plated attracting / relaxing part 3.

  The attracted object concentrate 13 is loosened by the shearing force of the spraying solution 11 and the object 12 contained in the object concentrate 13 is dispersed in the plating solution 11 in the circulation line. It returns to the said separation part via 32.

  In this way, by plating the plating object 12 using the plating apparatus A shown in FIGS. 1 to 3, the plating solution holding area 20 for holding the plating solution 11 and the plating solution tank 33. It is possible to sufficiently contact the fresh plating solution 11 circulating through the plating solution tank 33 while reliably circulating in the circulation system (closed system). As a result, stable plating can be performed to form a highly reliable plating film.

  The plating process will be described in more detail. The object to be plated 12 descending from the liquid cyclone 1a of the separation unit 1 is deposited in the object to be plated passing region 23, and plating is performed while gradually descending. In the upper part, the workpiece 12 is a fluidized bed in which the fluidized state is still maintained. At this time, among the partition walls 25 constituting the workpiece passage region 23 described above, a portion having no liquid permeability of the upper portion of the workpiece passage region 23 and a portion having the lower fluid permeability By making the boundary portion of the lower layer lower than the boundary portion between the deposited layer and the fluidized bed, plating can be performed with stable current density only on the object 12 that is stably deposited. This makes it possible to perform good plating.

Moreover, when plating is performed by the above-described method using the plating apparatus A according to the first embodiment,
(A) A configuration in which the anode 21 and the cathode 22 are arranged concentrically as described above,
(B) a configuration in which predetermined areas on the upper side and lower side of the plating object passage area are shielded by the mask members 24a and 24b;
(C) Only a predetermined region of the cathode 22, that is, a region corresponding to a region not shielded by the mask members 24 a and 24 b is made conductive, and another region, that is, a region shielded by the mask members 24 a and 24 b. Since the region corresponding to is covered with the upper insulating material 22a and the lower insulating material 22b, the object to be plated that passes through the object passing region 23 in a stable deposition state (the object to be plated is concentrated) In contrast, stable and good plating can be performed under conditions where the uniformity of the current density distribution is high.

  In addition, in the case of the plating apparatus A configured as in the first embodiment, in the analysis by simulation of the current density distribution of the surface layer of the object to be plated, the variation in the current density distribution is about 1/100 of that in the case of the rotary barrel plating. It has been confirmed that it can be improved. Note that the variation in the current density distribution is obtained by dividing the difference between the maximum value and the minimum value of the current by the average value of the current.

  Further, the plating can be performed more efficiently by making the distance between the surface of the partition wall 25 constituting the workpiece passing region 23 and the surface of the cathode in the central portion slightly larger than the deposition depth during plating of the plating bath characteristics. Will be able to do.

  Further, it has been confirmed that by performing plating by the method of Embodiment 1, the formed plating film is homogenized, the bending strength of the object to be plated is improved, and the occurrence of cracks is not recognized after the test.

  In addition, when the object to be plated is, for example, an ultra-small chip-type electronic component, it may float in the plating solution, and it may not be possible to perform good plating. In this case, the foam attached to the object to be plated is separated by the centrifugal force of the liquid cyclone, and the bubbles are discharged out of the system. Therefore, the object to be plated settles toward the object passing area without floating in the plating solution. . As a result, good plating can be reliably performed even when the object to be plated is small.

<Experimental example>
In the plating apparatus A having the configuration shown in FIGS. 1 to 3, the plating object passage region 23 of the plating unit 2 and the cylindrical partition wall 25 are made of a polyester mesh material. The inner diameter of the plating object passage region 23 was 20 mm.

Moreover, the height of the to-be-plated material passage area 23 was 200 mm, and the dimension in the height direction of the liquid-permeable mesh part was 150 mm, and the upper side 50 mm was constituted by a polypropylene pipe having no liquid permeability.
And the liquid cyclone 1a was connected as the isolation | separation part 1 on it.

Further, as the cathode 22, an elongated cylindrical (rod-shaped) titanium material was used as the cathode 22.
The cathode 22 covers the upper and lower portions with upper and lower insulating materials (insulating shrinkable tubes) 22a and 22b, and the surface between the upper insulated region and the lower insulated region is electrically conductive. The region having was made to function as a cathode terminal.

  Further, the anode 21 was disposed concentrically around the workpiece passage region 23 having the partition walls 25.

  Then, the plating solution holding region 20 was filled with the plating solution 11 to form a closed system. In addition, in the liquid cyclone 1a constituting the upper separation portion 1, the inner diameter of the charging solution 11 was 60 mm and the apex angle was 20 °.

  Moreover, the internal diameter of the connection part to the to-be-plated object passage area | region 23 of the plating part 2 of the liquid cyclone 1a was 18 mm slightly smaller than the internal diameter 20mm of the to-be-plated object passage area | region 23.

  The liquid cyclone 1a is provided with a supply port 50 through which the mixed fluid 10 of the plating solution 11 and the object to be plated 12 is swung along the inner wall, a vortex finder 51 in the center of the upper part, and a discharge chamber in the upper part. 52, and a configuration in which a discharge port 53 to the outside is provided at a position off the central axis of the discharge chamber 52 was used.

  The to-be-plated material attracting / unwinding portion 3 has a configuration including a tapered portion 3 a provided at the lower portion of the to-be-plated material passing region 23 and an ejector 40.

  That is, the plating solution 11 is supplied from one end side of the ejector 40, and the suction force generated by passing the throat portion 40a at a high speed causes the lower end portion of the plating object passage region 23 to pass through the tapered portion 3a. The plated product concentrate 13 was attracted, and the plated product 12 contained in the plated product concentrate 13 was dispersed in the plating solution 11 and returned to the separation unit 1 via a circulation line 32 described later.

  Then, in the plating apparatus A configured as described above, a chip-type multilayer ceramic capacitor having a length of 1.0 mm, a width of 0.5 mm, and a height of 0.5 mm is apparently 40 cc as the object to be plated 12, and the diameter is 0. 20 cc of a 7 mm metal sphere was introduced.

  Then, by operating the pump 34, the plating solution 11 is supplied to the ejector 40, and the throat portion 40 a is passed at a high speed, whereby the object 12 to be plated is removed from the lower end of the object passage region 23. The attracting / relaxing part 3 is attracted, a large shearing force is applied to disperse the object 12 to be plated in the plating solution 11, and the mixed fluid 10 containing the plating solution 11 and the object 12 is separated from the liquid cyclone 1 a of the separating part 1. It was circulated to.

  Then, while maintaining this circulation state, Ni plating was performed on the workpiece 12 by energizing the anode 21 and the cathode 22. Ni plating was performed using a general Watt bath under the conditions of a plating current of 5.0 A and 90 min.

After plating, the thickness of the Ni plating film formed on the workpiece 12 was measured with a fluorescent X-ray film thickness meter. As a result, the average value of the Ni plating film thickness was 4.2 μm and the film thickness variation CV was 5. It was as good as 3%. Film thickness variation CV is obtained by measuring the thickness of the plating film formed on the surface of the object to be plated with 30 fluorescent X-ray film thickness meters, obtaining the average value and standard deviation, and dividing the standard deviation by the average value. Asked.
Further, after the plating, no adhesion between the objects to be plated 12 and no adhesion between the media was observed.

  Further, using the same plating apparatus A, Sn plating was further applied to the object 12 to which Ni plating was applied. Sn plating was carried out using a commercially available Sn bath as the Sn plating solution under the conditions of a plating current of 3 A and 50 min.

  As a result of measuring the film thickness of the Sn plating film formed on the object 12 after plating, the average value of the film thickness of the Sn plating film was 3.9 μm and the film thickness variation CV was as good as 5.8%. .

  Further, after the plating, no adhesion between the objects to be plated 12 and no adhesion between the media was observed. This is considered to be due to the unraveling effect in the ejector 40.

  Further, using the same plating apparatus A, Ni plating and Sn plating were performed using a chip-type multilayer ceramic capacitor having a length of 0.4 mm, a width of 0.2 mm, and a height of 0.2 mm as an object to be plated 12.

  In performing the Ni plating, 40 cc of the object to be plated 12 and 20 cc of a Sn ball having a diameter of 0.3 mm are charged, and the Ni plating is performed using a general watt bath and under the conditions of a plating current of 8 A and 120 min. went.

  Moreover, the speed | rate which passes the to-be-plated object passage area | region 23 of the to-be-plated object 12 was 2 cm / sec. In addition, it is preferable that this speed shall be 0.1-30 cm / sec normally.

As a result of measuring the film thickness of the Ni plating film formed on the object 12 after plating, the average film thickness of the Ni plating film was 4.2 μm and the film thickness variation CV was as good as 6.5%. .
Further, after the plating, no adhesion between the objects to be plated 12 and no adhesion between the media was observed.

  Further, using the same plating apparatus A, Sn plating was further applied to the object 12 to which Ni plating was applied. Sn plating was carried out using a commercially available Sn bath as the Sn plating solution under the conditions of a plating current of 4 A and 90 min.

As a result of measuring the thickness of the Sn plating film formed on the object 12 after plating, the average value of the thickness of the Sn plating film was 4.4 μm, and the film thickness variation CV was as good as 5.4%. .
Further, after the plating, no adhesion between the objects to be plated 12 and no adhesion between the media was observed.

  From the above-mentioned results, it can be seen that the plating apparatus A and the plating method of the present invention are particularly meaningful when used for plating a fine object to be plated.

[Embodiment 2]
4 is a front sectional view showing a plating apparatus A according to Embodiment 2 of the present invention, and FIG. 5 is a plan sectional view. FIG. 6 is a front cross-sectional view showing an enlarged main part configuration.

  Similar to the plating apparatus A of the first embodiment, the plating apparatus B of the second embodiment compares the mixed fluid 10 containing the plating solution 11 and the object to be plated with the plating solution 11 and the object to be plated 12 before separation. A separation part 1 that is separated into a to-be-plated object concentrate 13 containing a high solid content concentration, and a to-be-plated object concentrate 13 that is positioned below the separation part 1 and separated by the separation part 1. A plating object 2 for electrolytically plating the plated object 12 and an object to be plated that is supplied to the separating part 1 by dispersing the plating object 12 contained in the plated object concentrate 13 after the plating is performed in the plating solution 11 It has an invitation / unwinding part 3.

And the plating apparatus B of this Embodiment 2 is
(A) A tubular cathode 22 configured to allow the plating solution 11 to pass through is used as the cathode;
(B) The tubular cathode 22 penetrates the center of the liquid cyclone 1a of the separation part 1 in the axial direction and penetrates the center of the plating object passage region 23 in the axial direction, so as to attract and loosen the plating object. Arranged to reach 3;
(C) The plating solution 11 that has passed through the inside of the tubular cathode 22 is ejected from the lower end side, thereby generating a suction force with a negative pressure around the periphery. In addition to attracting the product concentrate 13, the deposited object 12 can be dispersed by the shearing force of the plating solution 11 sprayed from the lower end of the cathode 22, so that the ejector used in the first embodiment is used. However, the configuration is different from that of the plating apparatus A of the first embodiment.
4-6, the part which attached | subjected the same code | symbol as FIGS. 1-3 has shown the part which is the same or corresponds.

Below, it demonstrates centering on a different point from the plating apparatus A of Embodiment 1. FIG.
In the plating apparatus B, a tubular cathode 22 is used as the cathode 22 as shown in FIGS. The tubular cathode 22 is disposed so as to penetrate the liquid cyclone 1 a of the separation part 1 and the plating object passage region 23 of the plating part 2 and reach the plating object attracting / relaxing part 3.
The tubular cathode 22 is tubular and is configured such that the plating solution 11 passes through the internal space 22c. The lower end of the cathode 22 is configured to function as the object to be plated attracting / relaxing portion 3. Yes.

  That is, the plating solution 11 separated by the separation unit 1 passes from the upper side to the lower side of the cathode 22 and is sprayed from the lower end, so that the plating force 11 is generated from the lower end portion of the plating object passage region 23. The to-be-plated thing concentrate 13 is comprised so that it may be attracted. In other words, in the plating apparatus B of the second embodiment, the lower end portion of the tubular cathode 22 uses the plating solution as a fluid and attracts the object concentrate 13 by the suction force generated by the flow of the plating solution. By functioning like an injector, it is configured to function as an object to be plated attracting / relaxing part 3. By configuring in this way, with a simple structure, a stable flow state of the object to be plated is ensured, variation in current density during plating is suppressed, and the object to be plated that has passed through the plating part is reliably attracted. Can be dispersed in the plating solution.

  The plating unit 2 includes a plating solution holding region 20 that holds the plating solution 11, an anode 21 that is disposed so that at least a part thereof is immersed in the plating solution 11, and at least a part of the plating solution 2. 11 is surrounded by a partition 25 that does not allow the object to be plated 12 to pass, and passes through the object to be plated passing region 23 through which the object to be plated concentrate 13 passes from the upper side to the lower side. A tubular cathode 22 arranged in the plating object passage region 23 so as to contact the object to be plated 12 and configured to allow the plating solution 11 to pass through the internal space 22c. Yes. That is, the plating part 2 has a tubular structure as the cathode 22, except that the lower end of the cathode 22 is disposed so as to reach the object to be plated attracting / relaxing part 3, A configuration similar to that of the first embodiment is provided.

Further, also in the plating apparatus B of the second embodiment, for the purpose of making the surface current density distribution of the partition wall 25 uniform, the plating object passage region is surrounded so as to surround the upper part and the lower part of the plating object passage region 23. An upper mask member 24 a and a lower mask member 24 b are disposed at a slight distance from the partition wall 25 constituting 23.

  Further, for the purpose of uniformizing the surface current density distribution of the cathode 22 in the region where plating is performed, as shown in FIGS. 4 to 6, from the height position corresponding to the lower end of the upper mask member 24 a of the cathode 22, The region between the positions corresponding to the upper end of the side mask member 24b has a conductive outer peripheral surface, and the region above the height position of the cathode 22 corresponding to the lower end of the upper mask member 24a and the lower side The regions below the height position corresponding to the upper end of the mask member 24b are covered with the upper insulating material 22a and the lower insulating material 22b, respectively.

  According to the plating apparatus B of the second embodiment configured as described above, the plating apparatus A of the first embodiment is used without requiring the ejector 40 used in the plating apparatus A of the first embodiment. As in the case, it is possible to stably perform high-quality plating on the object to be plated.

  In addition, using the plating apparatus B of the second embodiment, similarly to the experimental example of the first embodiment, a chip type multilayer ceramic capacitor having a length of 1.0 mm, a width of 0.5 mm, and a height of 0.5 mm is plated. As an object, an apparent amount of 40 cc and a metallic sphere having a diameter of 0.7 mm are apparently 20 cc. The same conditions as in the first embodiment, that is, a general watt bath, a plating current of 5.0 A, and a condition of 90 min. Then, electroplating was performed.

And after plating, as a result of measuring the film thickness of the Ni plating film formed on the object to be plated, the average value of the film thickness of the Ni plating film is 4.3 μm, and the film thickness variation CV is 5.3%. It was confirmed that good results similar to those in Embodiment 1 were obtained.
Also, there was no adhesion between the objects to be plated or between the media.

  Further, even when Ni plating and Sn plating were performed using a chip type multilayer ceramic capacitor having a length of 0.4 mm, a width of 0.2 mm, and a height of 0.2 mm as an object to be plated, the results in accordance with the case of Example 1 above It was confirmed that

  In the first and second embodiments, the case where the chip type multilayer ceramic capacitor is used as an object to be plated and the external electrodes are plated is described as an example. However, there are special restrictions on the type of object to be plated and the object to be plated. However, the present invention can also be applied to the case where the laminated coil component is plated and the surface conductor is plated.

  Further, the object to be plated is not limited to an electronic component, and may be a powder that can be subjected to electrolytic plating. For example, the object to be plated may be metal powder.

  In addition, the present invention is not limited to the above-described embodiment in other points, and various applications and modifications can be made within the scope of the present invention with respect to plating conditions and the like.

DESCRIPTION OF SYMBOLS 1 Separation part 1a Hydrocyclone 2 Plating part 3 To-be-plated object attraction / relaxation part 3a Tapered part below the to-be-plated object passing area 10 Mixed fluid containing plating solution and to-be-plated object 11 Plating solution 12 To-be-plated object 12a External Electrode 13 Plated object concentrate 20 Plating solution holding region 21 Anode 22 Cathode 22a Upper insulating material 22b Lower insulating material 22c Internal space 23 Plated material passing region 24a Upper mask member 24b Lower mask member 25 Bulkhead 31 Power supply 32 Circulation Line 33 Plating bath 34 Pump 40 Ejector 40a Throat section 50 Supply port 51 Vortex finder 52 Discharge chamber 53 Discharge port A, B Plating equipment

Claims (9)

(A) a separation unit that separates a mixed fluid containing a plating solution and an object to be plated into the plating solution and an object concentrate that contains the object to be plated at a higher solid content concentration than before separation;
(B) a plating part that is located below the separation part and that performs electrolytic plating on the object to be plated when passing the object concentrate to be plated separated by the separation part;
A plating solution holding area for holding the plating solution;
An anode disposed so as to be at least partially immersed in the plating solution;
At least a part is surrounded by a partition wall that allows the plating solution to pass therethrough but does not allow the plating object to pass therethrough, and a plating object passage region that allows the plating object concentrate to pass from above to below,
A plating portion comprising: a cathode disposed in the plating object passage region so as to come into contact with the plating object passing through the plating object passage region;
(C) The object to be plated is attracted from the lower end of the plating object passage area by the suction force generated by flowing the plating solution separated in the separation part, and the object to be plated is concentrated. A plating apparatus, comprising: a plating object attraction / relaxation part for dispersing the plating object contained in a body in the flowing plating solution and supplying the plating object to the separation part.   2. The plating according to claim 1, wherein the cathode is disposed along an axial direction so as to pass through a center of the plating object passing region, and the partition wall is disposed concentrically with the cathode. apparatus.   The cathode is disposed along the axial direction so as to pass through the center of the plating object passage area, and concentrically with the cathode so as to surround the plating object passage area outside the plating object passage area. The anode is disposed in a shape, and the plating object passes through a region between the outer peripheral surface of the cathode and the inner peripheral surface of the plating object passage region. The plating apparatus according to claim 1 or 2.   The plating apparatus according to claim 1, wherein the separation unit is a liquid cyclone having a tapered shape toward the plating unit located below.   The horizontal cross-sectional area of the upper end part of the plating part, which is a connection part with the lower end part of the separation part, is larger than the horizontal cross-sectional area of the lower end part of the separation part. The plating apparatus in any one of -4.   The said to-be-plated object attracting / unraveling part is an ejector or an injector comprised so that a suction force may be produced using the said plating solution as a fluid, The Claim 1 characterized by the above-mentioned. Plating equipment. The cathode has a tubular shape that penetrates the separation portion and the center of the plating portion in the axial direction and reaches the object to be plated attracting / unraveling portion,
The plating solution separated by the separation portion passes through the inside of the tubular cathode from the top to the bottom, and is sucked from the lower end, thereby attracting from the lower end portion of the plating object passage region. The plating apparatus according to claim 1, wherein the plating object concentrate is attracted. (A) separating the mixed fluid containing the plating solution and the object to be plated into the plating solution and the object to be plated containing the object to be plated at a higher solid content concentration than before separation;
(B) At least a part of the cylindrical object to be plated passing region in which the cathode is disposed along the axial direction in the center surrounded by a partition wall that allows the plating solution to pass but not the object to be plated; An object to be plated is made to pass through the object to be plated passing from above to below in a plating part provided with an anode arranged concentrically with the cathode outside the partition wall, so that the object to be plated is passed from above to below. Performing electrolytic plating on
(C) By the suction force generated by flowing the plating solution separated in the separating step , the object to be plated is attracted from the lower end of the object passage region, and the object to be plated is And a step of dispersing in the flowing plating solution.   9. The plating method according to claim 8, wherein electrolytic plating is performed on the object to be plated by repeating the steps (a), (b), and (c).

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