JP4358568B2 - Electroplating apparatus and electroplating method for electronic parts - Google Patents

Description

  The present invention relates to an electroplating apparatus and electroplating method for electronic components.

  As a conventional electroplating apparatus, there is one described in Japanese Patent Application Laid-Open No. 10-195698 (Patent Document 1). In this electroplating apparatus, a barrel whose upper end is open is inclined obliquely upward in a plating tank. A plating solution supply means is provided so that a part of the plating solution stored in the plating tank is poured into the barrel supported by the posture. In this electroplating apparatus, the barrel is rotated with a part of the barrel containing the object to be plated immersed in the plating solution in the plating tank, and the plating solution is injected into the barrel from the plating solution supply means. Thus, a plating film is formed on the object to be plated.

  Patent Document 1 also describes another embodiment of an electroplating apparatus, which is supported by a cylindrical barrel having a plurality of through holes for allowing a plating solution to flow through a wall surface in a plating tank. And a plating solution supply means for injecting a part of the plating solution stored in the plating tank into the barrel. In this electroplating apparatus, the barrel is rotated in the same manner as described above, and a plating solution is injected into the barrel to form a plating film on the object to be plated.

  Next, Japanese Patent Laid-Open No. 08-239799 (Patent Document 2) discloses a horizontal circular bottom plate fixed to the upper end of a vertical drive shaft, and an outer peripheral mounting flange fixed to the bottom plate and having an opening in the center. And a contact ring for energization for continuous or intermittent contact sandwiched between the bottom plate and the mounting flange, and a cover that forms a processing chamber that is lowered or cylindrically formed in the radial direction between the bottom plate and the bottom plate A porous window that is disposed in the vicinity of the contact ring and passes only the processing liquid, a supply pipe that supplies the processing liquid and the like to the processing chamber through the opening, a container that receives the processing liquid scattered from the porous window, and a container An electroplating apparatus is described that has a pump that feeds the accumulated processing solution to the supply pipe and an electrode that is inserted through the opening and contacts the plating solution. The plating process chamber is repeatedly rotated, decelerated, and stopped during the plating process. And covered Forming a plating film on the object.

JP-A-10-195698 Japanese Patent Laid-Open No. 08-239799

However, in the apparatus described in Patent Document 1, a cable having a so-called dangling tip, which is in contact with an object to be plated, is inserted into a barrel vessel supported in an inclined or horizontal position in a plating solution. At the same time, the material to be plated and the medium (hard steel particles such as stainless steel, zirconia, etc.) that facilitates crushing are added, and part or all of the barrel tank is immersed in the plating solution on which the anode is placed. This is a barrel plating method in which a plating film is formed by slowly rotating in one direction to capture the opportunity of contact energization between the workpiece and the dangula accompanying mixing and stirring of the media. Is suitable for forming a plating film on a relatively large workpiece.
However, while this barrel plating method can simplify the plating apparatus, in particular, a small object to be plated is light in weight and easily receives the buoyancy of the plating solution. Attempts have been made to put a large amount of media in a larger amount than the object to be plated, but because of the small size and small grains, excessive current density and generation of excessive parts are unavoidable, and in parts where the current density is excessive, Stable plating film could not be obtained due to plating aggregation due to excessive growth of plating precipitation and floating of the object to be plated, etc., and the media diameter that grows excessively with the progress of plating processing was selected or controlled A reduction in production efficiency and an increase in management man-hours are required, for example, a re-input of a certain particle size is required and a long time is required for the plating process.

  In addition, the apparatus described in Patent Document 2 is intended to form a plating film for small objects, while rotating a plating processing chamber in which a porous window for discharging a plating solution is integrally connected to form a cell. A plating film is formed by discharging the plating solution from the peripheral porous window where centrifugal force works while supplying the plating solution from the upper opening, but the concentration of the plating solution inside the plating device changes over time. In order to prevent this, the plating solution is supplied by a combination of an electric pump and a liquid level sensor. Therefore, complicated control is required, and the drive motor and shaft are located under the plating process chamber. Structures such as leakage and insulation have become complicated, and the plating apparatus has been fixed, so that it has poor versatility.

  In addition, electronic devices having a rectangular shape, a cylindrical shape, a cylindrical shape, and the like mounted on a circuit board, such as resistors, capacitors, inductors, etc., are being developed as electronic devices seen in recent portable information terminals are becoming lighter and thinner. Even in chip-type electronic components such as thermistors or fuses, the shape and outer dimensions are reduced in size and thickness in response to this, for example, nominal length x nominal width is 1.0 mm x 0.5 mm, Miniaturization is progressing with changes of 0.6 mm × 0.3 mm and 0.4 mm × 0.2 mm. In these chip-type electronic components, the requirements for the electrodes are stricter, the area occupied by the electrodes is relatively small, the plating film has a substantially uniform thickness, and the electrode land on the circuit board is good. Solderability is required.

  The present invention solves such a conventional problem, and even if the electronic components have extremely light and thin shapes and external dimensions, it is not necessary to insert media, and the structure of the plating apparatus is reduced in size and simplified. Electroplating apparatus and electroplating method for electronic components capable of ensuring a desired plating film in a short time and with a substantially uniform thickness The purpose is to provide.

In order to solve the above problems, in the present invention, in a plating tank provided with an anode, the plating drum is provided at the lower end of the drive shaft so as to be driven to rotate, and the plating drum is provided with a cathode ring on the inner wall. An insulating ring, a bottom insulating plate that seals a bottom of the insulating ring, and an upper insulating plate fixed to the upper side of the insulating ring, and the upper insulating plate is rotated when the plating drum is driven to rotate. Provided with an electroplating device for electronic parts, wherein a through hole is provided so that the plating solution flows from the inside of the plating drum to the outside and flows from the outside to the inside by the centrifugal force acting on Is done.
In the electroplating apparatus of the present invention, the plating drum is attached to the lower end of the drive shaft and immersed in the plating tank, and the drive shaft rotates only the plating drum. The plating drum can be replaced relatively easily in accordance with the specifications of the electronic component that is the object to be plated. Moreover, even if the shape and outer dimensions of the object to be plated are light, thin and small, the apparatus of the present invention can collect the object to be plated on the cathode ring by simply rotating the plating drum, and the plating solution can be insulated from the upper part. Since it can be convected from the hole in the plate into the plating drum, it is possible to relatively reliably form a plating film with a desired thickness and a uniform thickness on electronic components with light and thin shapes and external dimensions. become.

In the electronic component electroplating apparatus according to the present invention, the upper insulating through hole is composed of a first through hole and a second through hole, and the first through hole has a plating solution inside the cathode ring. At least one of the second through holes is provided at a position spaced apart from the cathode ring by a predetermined length so as to flow out of the plating drum concentrically, and the second through hole is disposed inside the plating drum inside the first through hole. Can flow in.
Here, referring to the relationship between the distance between the first through hole and the cathode ring and the current density on the inner peripheral surface of the cathode ring, the plating drum is driven to rotate when both are provided close to each other. When energized, the current density is locally increased on the inner peripheral surface of the cathode ring, and it is easy to cause a problem that excessive plating precipitates and blocks the through-hole. On the other hand, when both are provided with a moderate separation, the current density is substantially uniform on the inner peripheral surface of the cathode ring even if the plating drum is energized while being rotationally driven. It is possible to relatively reliably form a substantially uniform plating film with a desired thickness.
Therefore, in the electroplating apparatus of the present invention, the separation distance between the first through hole and the cathode ring is such that the current density on the inner peripheral surface of the cathode ring is substantially uniform when energized while rotating the plating drum. Is set to a length such that
In the electroplating apparatus having the above-described configuration, the current density excess in the vicinity of the first through hole from which the plating solution flows out and at the top of the inner periphery of the cathode ring is alleviated, and a stable current density is achieved on the inner peripheral surface of the cathode ring. Obtainable. In addition, even if the anode is attached to the outside of the plating drum, the first through hole for the plating solution outflow is provided at a position spaced apart by a predetermined length inside the cathode ring, so the vicinity of the first through hole The plating solution can be prevented from being excessively deposited on the plating tank. When the plating drum is rotated in the plating tank, the plating solution flows out from the first through hole and the plating solution flows from the second through hole. Thus, convection of the plating solution in the plating drum is promoted, and a decrease in the metal concentration of the plating solution in the plating drum, particularly in the vicinity of the cathode ring, can be suppressed.

In the electroplating apparatus of the present invention, the bottom insulating plate may be provided with a surface formed to be inclined downward toward the rotation center of the plating drum.
In the electroplating apparatus of the present invention, since the plating drum is controlled to rotate in both forward and reverse directions in a cycle of slow speed, constant speed, deceleration, and stop, when the plating drum rotates at a constant speed, The object is subjected to centrifugal force and gathers in the cathode ring and is energized in contact. However, in the process until the plating drum is decelerated and stopped, the object to be plated moves along the downward inclined surface as the centrifugal force decreases. Then, it moves in a direction away from the cathode ring, and at this time, stirring and mixing of the object to be plated is promoted. On the other hand, in the process from the slowing of the plating drum to the constant speed rotation, the object to be plated moves again to the cathode ring while being stirred and mixed as the centrifugal force increases. By such a stirring / mixing action of the object to be plated, the plating film hardly varies from object to object, and it becomes possible to form a substantially uniform plating film with a desired thickness for each object.

In the electroplating apparatus of the present invention, a backflow prevention valve may be provided so as to prevent backflow of the plating solution from the second through hole.
If the backflow prevention valve is provided in this way, the plating solution or the object to be plated flows out from the second through hole when the plating drum shifts from the normal rotation to the reverse rotation or when the plating drum shifts from the reverse rotation to the normal rotation. The possibility can be made extremely small.

  In the electroplating apparatus of the present invention, the diameter of the plating drum may be larger than the length of the plating drum in the rotation axis direction. According to this configuration, the plating drum can be reduced in size and simplified. That is, when the object to be plated is a small chip-type electronic component having a light, thin and small shape and external dimensions, the plating film is formed even if the length of the plating drum in the rotation axis direction is relatively short. In this respect, a sufficient effect can be obtained, and the electroplating apparatus can be reduced in size and simplified.

  In the electroplating apparatus of the present invention, a plating solution introduction through hole may be provided on the inner surface of the drive shaft so as to promote the circulation of the plating solution in the plating tank and the plating drum. According to such a configuration, it becomes possible to forcibly promote the convection / circulation of the plating solution according to the volume of the plating drum and the amount of the object to be plated.

  In the electroplating apparatus of the present invention, the upper insulating plate may share a through hole through which the plating solution flows into the plating drum and a through hole through which the plating solution flows out of the plating drum. It is also possible to form the cathode ring at a position separated from the inside of the cathode ring. With this configuration, it is possible to further reduce the size and simplify the plating drum in an electroplating apparatus that uses a small chip-type electronic component having a light, thin, small shape and external dimensions as an object to be plated.

In the present invention, a plating drum provided with at least a cathode ring attached to the inner wall of the insulating ring, a bottom insulating plate that seals the bottom of the insulating ring, and a through hole that allows a plating solution to enter and exit the inside of the cathode ring, A chip-type electronic component, which is an object to be plated, is accommodated, the plating drum is immersed in a plating tank provided with an anode, and is rotated while holding the plating drum so that the bottom insulating plate is substantially horizontal. The plating solution is convected in the plating tank and inside the cathode ring by the rotating centrifugal force of the plating drum, and chip-type electronic components are gathered in the cathode ring and contacted and energized, and the rotation speed is gradually reduced or reduced and stopped. There is provided an electroplating method for an electronic component characterized in that a desired plating film is formed by repeating agitation / mixing and discrete steps.
In the electroplating method of the present invention, the plating solution is convected by the rotating centrifugal force, the electronic parts as the objects to be plated are gathered on the cathode ring, and the rotating centrifugal force is increased or decreased by slowing or decelerating and stopping the rotation. Since the object to be plated is agitated / mixed and discretely repeated, the plating film can be formed in a substantially uniform and desired thickness without variation for each object to be plated.

In the electroplating method for an electronic component according to the present invention, the plating drum includes one cycle including a forward rotation and a reverse rotation. In each of the forward rotation step and the reverse rotation step, a slow speed, a constant speed rotation, It has a step of decelerating and stopping, and can be configured to energize during constant speed rotation.
According to the above configuration, since the anode is attached to the outside of the plating drum immersed in the plating solution, the objects to be plated are gathered and energized so as to cover the surface of the cathode ring by centrifugal force. By suppressing the excessive plating deposition and repeating forward and reverse, the mixing and stirring of the object to be plated proceed smoothly, so there is little variation in the thickness of the plating film, and the unevenness of the plating film surface is suppressed Is obtained.

In the electroplating method for an electronic component according to the invention, it is also possible to form a plating film without mixing media in an object to be plated in a plating drum.
According to the above configuration, since the plating current is efficiently used for plating deposition of only the object to be plated, there is little wasteful reduction of the plating material, and the plating material cost can be reduced. Also, by not using media, there is no need for media management or separation from the object to be plated, and it is possible to obtain an effect that the work of the plating process can be simplified.
In the electroplating method of the electronic component of the invention, at least a cathode ring attached to the inner wall of the insulating ring, a bottom insulating plate for sealing the bottom of the insulating ring, an upper insulating plate fixed on the upper side of the insulating ring, The upper insulating plate has a through-hole that allows the plating solution to enter and exit the plating drum. The chip-type electronic component, which is the object to be plated, is accommodated in the plating drum, and the plating drum is immersed in a plating tank provided with an anode. In addition, the plating drum is rotated while being held so that the bottom insulating plate is substantially horizontal, and the plating solution is convected in the plating tank and inside the plating drum by the rotational centrifugal force of the plating drum. , the plating drum are assembled chip-type electronic component on the cathode ring during constant speed rotation of the normal rotation process and the reverse rotation process in the rotational drive of the contact energized, and Electroplating method of an electronic component and forming a desired plated film by repeating the agitation and mixing by the slow or deceleration and stopping of the rotation discrete and are also provided.

  The present invention is a compact chip-type electronic component having a thin, short and small shape and external dimensions, in which a plating drum is immersed in a plating solution in a plating tank provided with an anode to obtain a centrifugal rotational force to perform plating deposition. Even so, it is not always necessary to insert media into the plating drum, and the structure of the plating apparatus itself can be reduced in size and simplified, so that it can be followed by degreasing, washing, or forming the required plating film in the plating process. Also, in other plating film formation processing, the plating drum can be easily transferred to other processing tanks, and is versatile, easy to maintain, and has a uniform thickness and a desired thickness in a relatively short time. The plating film can be formed.

An embodiment of the present invention will be described with reference to FIGS.
FIG. 1A is a perspective view in the process of manufacturing a chip-type electronic component such as a resistor, a capacitor, an inductor, or a thermistor, and includes a front electrode film 1a and a back electrode film 1c. The lower electrode film 1 made of the end face electrode film 1b and the like is formed. Moreover, FIG.1 (b) is the perspective view which showed the aspect which formed the plating film 2 in the to-be-plated object of Fig.1 (a). In the present invention, a chip-type electronic component that requires the plating film 2 to be further formed on the surface of the lower electrode film 1 as described above will be described as a “plated object”. The plated film 2 is intended to prevent, for example, elution of the lower electrode film 1, lower the resistance of the electrode portion, and improve solder bonding with the electrode land of the circuit board. One or more layers are formed. The plating film is formed by depositing, for example, a Cu-based, Ni-based, Sn-based, or Sn / Pb-based metal. Here, the “system” refers to a single or at least one or more metals. A material containing The apparatus and method of the present invention are not limited to rectangular chip-shaped electronic components having an insulating substrate as shown in the figure, and can be applied to, for example, electronic components having a cylindrical shape or a cylindrical shape. It is.

  2A and 2B are cross-sectional views schematically showing the electroplating apparatus 10 of the present invention. FIG. 3A is a plan view of the plating drum 20, and FIG. 3B is a cross-sectional view of the plating drum 20. In the electroplating apparatus 10 of the present invention, the drive motor 11 is supported and fixed above the plating tank 8 by the support arm 12, the drive shaft 15 extends downward from the drive motor 11, and the arm 18 is attached to the lower end of the drive shaft 15. The plating drum 20 is attached via the, and the plating drum 20 is supported so as to be immersed in the plating solution 7. Note that the drive motor 11 can be controlled so that the drive shaft 15 can be switched appropriately in both forward and reverse directions.

  Here, the drive shaft 15 is provided so as to be positioned at the center of the plating drum 20. The drive shaft 15 is provided with a sliding ring 16, and a brush terminal 17 is provided so as to contact the sliding ring 16, and a cord 13 extending to the cathode power source is connected to the brush terminal 17. On the other hand, an anode plate 6 is immersed in the plating tank 8, and a cord 5 extending to the cathode power source is connected to the anode plate 6.

As shown in FIGS. 3A and 3B, the plating drum 20 has an upper insulating plate 21 and a bottom insulating plate 23 fixed to the upper and lower openings of the insulating ring 22 by bolts and nuts 27, respectively. A metal cathode ring 24 is attached to the inner wall. Such tightening and fixing with the bolts and nuts 27 facilitates the introduction and removal of the object to be plated from the plating drum 20, and further facilitates disassembly and maintenance.
The plating drum 20 has an arm 18 attached to the upper insulating plate 21 with bolts and nuts 25, and the lower end of the drive shaft 15 is fixed to the arm 18. The insulating plate 21 and the bottom insulating plate 23 are supported so as to be substantially parallel. Due to such a configuration, the plating drum 20 is integrated with the drive motor 11 and the drive shaft 15 that rotationally drive the plating drum 20. Then, removal from the plating tank 8 or degreasing, cleaning, and movement for another plating film forming process following the formation of a predetermined plating film can be easily performed.
Bolts and nuts 25 used for fixing the arm 18 and the plating drum 20 are in contact with the cathode ring 24, whereby a cathode conductive path is formed. That is, as an electrical conduction path connecting the cathode power source to the cathode ring 24, the cord 13, the brush terminal 17, the sliding ring 16, the drive shaft 15, the arm 18, and the bolt / nut 25 can be energized in this order. It is comprised so that it may connect, and size reduction and simplification of an electroplating apparatus are achieved by forming the conductive path of such a cathode. In this case, a suitable insulation treatment is performed so as to insulate the surfaces of the fastening bolts / nuts 27, the arm 18, and the drive shaft 15 exposed to the plating solution.
The above is an example of forming the conductive path of the cathode, and the conductive path may be separately formed with a coated conductor. In addition, as for the shape of a plating drum, it is desirable to reduce the unevenness | corrugation of a surface so that a plating solution may not excessively ripple in a plating tank during rotation.

The bottom insulating plate 23 of the plating drum 20 is a non-porous plate so as to seal the bottom opening of the insulating ring 22. On the other hand, the upper insulating plate 21 is provided with a first through hole 21a at a position spaced a predetermined length from the upper end of the cathode ring 24 toward the drum rotation center side, and further, the drum rotation center than the first through hole 21a. A second through hole 21b is formed at a position spaced a predetermined length toward the side. The first through-hole 21 a is formed in at least one or more slits in a substantially concentric arrangement with the cathode ring 24, and the second through-hole 21 b is located substantially at the center of the upper insulating plate 21.
Note that a mesh net 26 may be provided on the inner surface side of the upper insulating plate 21 as shown in FIGS. This is effective when it is not necessary to increase the number of revolutions of the plating drum 20. Thus, even when the plating drum 20 is driven to rotate, the object to be plated 3 remains in the first through hole 21 a and the second through hole. Outflow from 21b can be prevented. The first through hole 21a can be formed in a circular shape or a polygonal shape. 3 (a) and 3 (b), the first through hole 21a is formed vertically, but the first through hole 21a may be formed obliquely toward the outer periphery. The efficiency of discharging the plating solution can be increased.
In the plating drum 20, as shown in FIG. 3B, a more compact plating drum can be obtained by forming the plating drum so that the diameter R of the plating drum is larger than the length L of the plating drum in the rotation axis direction. It is provided.

As described above, when the second through hole 21b is disposed near the rotation center of the plating drum 20 and the first through hole 21a is disposed near the outer periphery of the plating drum 20, when the plating drum 20 is driven to rotate, the plating solution Flows into the plating drum 20 from the second through hole 21b, flows out of the plating drum 20 from the first through hole 21a, and convection of the plating solution 10 is promoted between the plating tank 9 and the plating drum 20. By promoting the convection in this way, the metal concentration in the plating solution is maintained in the vicinity of the cathode ring 2 and maintained at a predetermined metal concentration. In the plating drum 20, the chip-type electronic component 3 which is an object to be plated is accommodated, and when the rotation drive is stopped, as shown in FIG. However, when the plating drum 20 is driven to rotate, the objects to be plated 3 receive the rotational centrifugal force and the flow of the plating solution, and gather to come into contact with the cathode ring 2.
Thus, the first through hole 21a functions as a discharge port for circulating the plating solution from the inside of the plating drum 20 to the plating tank 9, but the first through hole 21a, which is a discharge port for this plating solution, As described above, the current density does not increase in the vicinity of the upper end portion of the cathode ring 2 because it is spaced from the upper end portion of the cathode ring 2 toward the rotation center side of the drum by a predetermined length. 2, a substantially uniform current density can be obtained, and plating deposition in the vicinity of the first through hole 21 a that is a plating solution discharge port is extremely effectively suppressed.

  The plating tank 8 has a capacity capable of maintaining a suitable metal concentration and liquid temperature so as to withstand the required number of plating processes from the viewpoint of production efficiency in plating film formation, and is provided on both sides or around the plating drum. The anode plate 6 is disposed in the vicinity of the inner wall so as to be positioned, and may be configured as a single tank type, or a circulation type (not shown) so as to maintain a suitable metal concentration and liquid temperature. )).

A method of applying a plating film to an object to be plated by an electroplating apparatus having the basic configuration as described with reference to FIGS. 2 and 3 will be described.
The object 3 to be plated is put into the plating drum 20 suspended by the drive shaft 15 and the arm 18, and then the plating drum 20 is immersed in the plating tank 8.
Next, the drive motor 11 is operated and controlled in a cycle as shown in the timing chart of FIG. That is, one cycle is composed of a forward rotation section A and a reverse rotation section C, and in the forward rotation section A, the step e that slows down from the stop P reaches the constant speed rotation B, and the stop point P1 is reached by the step f that decelerates. It reaches. On the other hand, in the reverse rotation section C, the rotation starts in the reverse rotation direction, and similarly includes a slow speed step e ′, a constant speed rotation D, and a deceleration step f ′.
At the rotation stop points P, P1, and P2 of the plating drum, even if the object 3 is small and light in weight, it is discrete from the cathode ring 2 and de-energized as shown in FIG. It has become. This plating drum gradually gathers on the inner wall of the cathode ring 2 while the discrete workpieces 3 are agitated and mixed in the process of gradually increasing the rotational speed by obtaining the slow steps e and e ′. Contact is encouraged. During the section of constant speed rotation B, D, the objects to be plated 3 gather together so as to come into contact with the cathode ring 24 by the action of centrifugal force, contact energization is performed reliably, and the plating solution also acts by the centrifugal force. As a result of convection being promoted by and accepting the object 3 to be plated, a plating film is formed on the object 3 to be plated. Then, after the constant speed rotations B and D, the set of the objects to be plated 3 is released at the deceleration steps f and f ′, and the stirring / mixing is started.
Compared to the method of stirring / mixing and energization in Patent Document 1, the present invention forcibly performs set / energization, stirring / mixing, and discrete by including normal rotation and reverse rotation in one cycle. It is not always necessary to insert media such as technology.
Here, in the timing chart of FIG. 4, the chart is continuous with deceleration, stop, and slow speed. However, stirring / mixing and discrete acceleration are considered in consideration of the relationship between the rotational speed, the gradient of slowdown, and slow speed. Therefore, a predetermined length of stop time may be provided.

Next, aspects of the electroplating apparatus different from those in FIGS. 2 and 3 will be described with reference to FIGS. 5 to 9, the same components as those in FIGS. 2 and 3 are denoted by the same reference numerals, and further description thereof is omitted.
FIG. 5 shows a cross section of the plating drum. Here, the inclined surface 33a is provided on the outer peripheral portion of the bottom insulating plate 33 so as to be inclined downward toward the rotation center of the plating drum. . The inclined surface 33 a is formed by reducing the thickness of the central portion of the bottom insulating plate 33. If such an inclined surface 33a is provided, the object to be plated moves in the downward direction along the inclined surface 33a in the process of decelerating the plating drum 20 from the constant speed rotations B and D, thereby stirring, mixing, and discrete Will be promoted. On the contrary, in the slow speed step, the vicinity of the cathode ring 24 is narrower than the vicinity of the central portion of the bottom insulating plate 33, so that the density of the objects to be plated on the inner wall of the cathode ring 2 is more effectively promoted. Is.
In FIG. 5, the attachment mode of the insulating ring 22 and the cathode ring 24 is formed as shown in FIG. 6A. However, the shape and size of the object to be plated and the cathode ring 24 of the object to be plated are shown. The insulating ring 22 and the cathode ring 24 may be configured in the shapes shown in FIGS. 6B, 6C, and 6D in consideration of the gathering state of the current and the current density at that time.

Next, FIG. 7 is a view showing a backflow prevention valve 38 that covers the second through hole 21b of the upper insulating plate 21 so as to be freely opened and closed. This is to prevent the plating solution from flowing backward from the second through-hole 21b in the case of abrupt transition from normal rotation to reverse rotation, or from reverse rotation to normal rotation. This prevents it from flowing out of the plating drum. In the backflow prevention valve 38, a closing plate 38c is pivotally attached to a lower end of a shaft 38a provided so as to be movable up and down, and a spring 38b for energizing the closing plate 38c upward is mounted on the shaft 38a. When the rotation approaches the stop, the closing plate 38c acts so as to close the second through hole 21b. During the rotation, the plating solution is accompanied by the plating solution flowing out of the first through hole 21a. At this time, the pressure is obtained so as to supplement the plating solution, the closing plate 38c is opened, and the plating solution flows in.
FIGS. 8A to 8C are views showing a backflow prevention valve 39 in a mode different from that in FIG. In the backflow prevention valve 39, an introduction ring 39b is fixed inside an introduction cylinder 39a fixed to the second through hole 21b, and the introduction ring 39b includes a shaft insertion hole 39b-1 and a plating solution flow passage 39b-2. The shaft 39c is inserted into the shaft insertion hole 39b-1 so as to be movable up and down, a closing plate 39d is pivotally attached to the lower end of the shaft 39c, and a spring fixture 39e is fixed to the upper end of the shaft 39c. The upper and lower ends of the mounted spring 39f are in contact with the spring fixture 39e and the introduction ring 39b. Therefore, when no external force is applied to the closing plate 39d, that is, when the plating drum 20 stops rotating and the plating solution does not pass through the second through hole 21b, as shown in FIG. The spring 39f pushes the shaft 39c upward, and the closing plate 39d closes the lower end of the introduction tube 39a. Similarly, the closing plate 39d closes the second through hole 21b even when the plating drum 20 decelerates the rotation. On the other hand, when the plating drum 20 is rotating, the closing plate 38c is opened as shown in FIG. 8A by the pressure at which the plating solution flows into the plating drum 20 from the second through hole 21b. Is done.

  In the embodiment of FIG. 9, the upper insulating plate 21 is provided with a single hole 21c, that is, a shared through hole 21c. The shared through hole 21c is formed by the first through hole 21a and the second through hole in FIG. It has a function with the hole 21b, and the plating solution flows out and flows in through the common through hole 21c. The common through hole 21c is preferably stretched with a mesh net 28 as shown. The shared through-hole 21 c is provided at a position where the edge of the hole is separated from the upper end of the cathode ring 24 by a predetermined length. With the configuration as shown in FIG. 8, even when the rotational speed is low, a suitable plating film can be formed on a lighter, thinner, smaller and smaller chip-type electronic component using a compact plating drum.

  FIG. 10 illustrates only the drive shaft 15 and the arm 18 in the electroplating apparatus. Although not illustrated, a second through hole b21 is provided below the arm 18. In FIG. 10, the drive shaft 15 is provided with a pipe 15a for allowing the plating solution to pass through. The pipe 15a has a blowout port on the lower surface of the arm 18, and this blowout port is disposed opposite the second through hole 21b. Is provided. The pipe 15a is for introducing the plating solution sucked up from the plating tank 9 into the plating drum 20 through the second through hole 21b. According to this aspect, in consideration of the shape and dimensions of the object to be plated, if the plating solution is introduced into the plating drum 20 at an inflow rate that does not cause excessive dispersion of the object to be plated, the convection of the plating solution can be achieved. It can be effectively promoted. At this time, the portion exposed to the plating solution is covered with insulation.

  In the embodiment described above, the nominal length is 0.6 mm × the nominal width is 0.3 mm using the plating drum 20 including the upper insulating plate 21 and the bottom insulating plate 23 of FIGS. A chip-type resistor having a rectangular shape having a nominal resistance value of 10 kΩ is used as a sample of an object to be plated, and approximately 300,000 pieces of the object to be plated are accommodated without putting media in the plating drum 20. An example is shown in which an Sn plating film is formed on the exposed surface of the lower electrode film 1 (a) following the formation of the Ni plating film.

The plating deposition timing chart shows the results of observing the thickness of the deposited plating film using the same profile as in FIG. In addition, 20 samples are extracted from the samples in which the formation of each plating film is completed, and the results of measuring the plating film thickness are shown by cutting almost the center in the length direction of the sample.

  As shown in the results of the examples, without adding media, plating agglomeration did not occur, the plating film surface was dense, and a plating film with stable variations in plating film thickness was obtained. Further, in general, when the resistance value is high, it is necessary to supply a large current, and the plating time is also long. According to the results of the examples, the plating time is significantly longer than that of the conventional apparatus. As can be seen in the formation of the plating film of the resistor, the plating film can be formed in a short time with a substantially constant value of the plating current without depending on the constant of the rated resistance value. In the examples of the present invention, the objects to be plated having predetermined external dimensions are exemplified as samples in Tables 1 and 2, but the scope of the present invention is not particularly limited thereto.

(A) is the perspective view in the manufacture process of to-be-plated object, (b) is the perspective view which showed the aspect which formed the plating film in the to-be-plated object of (a). It is sectional drawing which showed typically the electroplating apparatus of this invention. (A) is a top view of a plating drum, (b) is sectional drawing of a plating drum. It is a timing chart at the time of rotating a plating drum. FIG. 4 is a partial cross-sectional view illustrating an electroplating apparatus of a mode different from those in FIGS. 2 and 3. FIG. 6 is a partial cross-sectional view illustrating different attachment states of an insulating ring and a cathode ring in the plating drum of FIG. 5. It is the figure which showed the backflow prevention valve which covers a 2nd through-hole so that opening and closing is possible. (A)-(c) is the figure which showed the backflow prevention valve of the aspect different from FIG. This is a mode in which a common through hole is provided in the upper insulating plate. Only the drive shaft and the arm in the electroplating apparatus of the aspect different from FIG.2 and FIG.3 are shown in figure.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 To-be-plated object 6 Anode 7 Plating solution 8 Plating tank 10 Electroplating apparatus 15 Drive shaft 18 Arm 20 Plating drum 21 Upper insulating plate 21a First through hole 21b Second through hole 21c Common through hole 22 Insulating ring 23 Bottom insulating plate 24 Cathode ring 38 Backflow prevention valve 39 Backflow prevention valve

Claims (11)

In the plating tank provided with the anode, the plating drum is provided at the lower end of the drive shaft so that the plating drum can be rotationally driven. The plating drum has an insulating ring with a cathode ring attached to the inner wall, and a bottom of the insulating ring. A bottom insulating plate to be sealed; and an upper insulating plate fixed to the upper side of the insulating ring. The plating solution is applied to the upper insulating plate by centrifugal force acting when the plating drum is driven to rotate. An electroplating apparatus for electronic parts, wherein a through hole is provided so as to flow out from the inside to the outside and to flow from the outside into the inside. The through hole of the upper insulating plate is composed of a first through hole and a second through hole, and the first through hole allows the plating solution to flow out of the plating drum concentrically inside the cathode ring. Wherein at least one of the second through holes is provided at a position spaced apart from the cathode ring by a predetermined length, and the plating solution flows into the plating drum inside the first through hole. The electroplating apparatus for electronic parts according to claim 1. 3. The electroplating apparatus for an electronic component according to claim 1, wherein the bottom insulating plate has a surface formed so as to be inclined downward toward the rotation center of the plating drum. The electroplating device for an electronic component according to claim 2, further comprising a backflow prevention valve so as to prevent the plating solution from flowing back from the second through hole. The electroplating apparatus for an electronic component according to any one of claims 1 to 4, wherein a diameter of the plating drum is larger than a length of the plating drum in a rotation axis direction. The inner surface of the drive shaft, electrons according to any of claims 1 to 5, characterized in that it comprises a plating liquid introduction holes to encourage circulation of the plating solution of the plating tank and the plating in the drum Electroplating equipment for parts. In the upper insulating plate, from the cathode ring, a through hole through which the plating solution flows into the plating drum and a through hole through which the plating solution flows out from the plating drum are shared by the same through hole. The electroplating apparatus for an electronic component according to claim 1, wherein the electroplating apparatus is also formed at a position spaced inward. At least a cathode ring attached to the inner wall of the insulating ring, a bottom insulating plate for sealing the bottom of the insulating ring, an upper insulating plate fixed to the upper side of the insulating ring, and the upper insulating plate to the inside of the plating drum A plating drum having a through-hole through which a plating solution can enter and exit is accommodated with a chip-type electronic component that is an object to be plated. The plating drum is immersed in a plating tank provided with an anode, and the bottom insulating plate is substantially horizontal. a plating drum is rotated while holding the so, the centrifugal force of the plating drum, causes convection of the plating solution in said plating drum interior and the plating bath, the chip-type electronic part on the cathode ring It is characterized by forming a desired plating film by collecting and energizing contact, and repeating stirring / mixing and discrete by slowing down or slowing down and stopping the rotation. Electroplating method of the electronic component to be. The plating drum is composed of one cycle including forward rotation and reverse rotation, and each of the forward rotation step and the reverse rotation step includes a step of slow speed, constant speed rotation, deceleration and stop, and a constant speed. The method of electroplating an electronic component according to claim 8, wherein energization is performed during high-speed rotation. The electroplating method for an electronic component according to claim 9, wherein a plating film is formed in the plating drum without mixing media in an object to be plated. At least a cathode ring attached to the inner wall of the insulating ring, a bottom insulating plate for sealing the bottom of the insulating ring, an upper insulating plate fixed to the upper side of the insulating ring, and the upper insulating plate to the inside of the plating drum A plating drum having a through-hole through which a plating solution can enter and exit is accommodated with a chip-type electronic component that is an object to be plated. The plating drum is immersed in a plating tank provided with an anode, and the bottom insulating plate is substantially horizontal. The plating drum is rotated while being held so that the plating solution is convected by the rotating centrifugal force of the plating drum in the plating tank and inside the plating drum, and the forward rotation in the rotation driving of the plating drum is performed. During the constant speed rotation of the process and the reverse rotation process, the chip-type electronic components are assembled on the cathode ring and contacted with electricity, and the rotation is slowed down, decelerated, and stopped. Electroplating method of an electronic component and forming a desired plated film by repeating the discrete and 拌 and mixing.

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