JP6916028B2 - Plating equipment for electronic components - Google Patents

Description

The present invention relates to, for example, a plating device for electronic components for plating electrodes of chip-type electronic components.

Small electronic components such as chip-type resistors are plated to form external electrodes in order to improve solderability to circuit boards and ensure electrical continuity. As a plating device for forming such an external electrode, for example, an object to be plated and a plating solution are put into a plating tank, and the plating tank is horizontally (forward and reverse) alternately, continuously or intermittently. There is a known device for plating by rotating the plate.

In such a plating apparatus, since the metal concentration in the plating tank gradually decreases due to the electrolytic reaction, the plating solution is configured to constantly circulate between the plating tank and the separately provided mother tank.

For example, in Patent Document 1, in order to prevent the object to be plated and the conductive medium from aggregating due to centrifugal force in the plating processing chamber configured to be rotatable, the rotation speed of the plating processing chamber changes. A method of performing plating while rotating continuously or intermittently in an embodiment is disclosed. Further, the plating apparatus of Patent Document 1 is provided with an annular plating extraction portion (porous ring) made of a porous material capable of extracting and discharging only the plating solution to the outside without passing the object to be plated. The extracted plating solution is configured to be circulated to the plating processing chamber via a circulation path.

Further, in Patent Document 2, a plating processing chamber for accommodating an object to be plated and the like has a rotating body having an opening at the top and a cathode provided at the outer peripheral portion, and a tubular member arranged at the center of the rotating body. , Equipped with an anode arranged inside the rotating body, overflows the tubular member, allows the plating solution to flow into the tubular member, and returns the inflowing plating solution from the opening to the plating processing chamber for plating. A plating apparatus that circulates a liquid is disclosed.

Japanese Unexamined Patent Publication No. 2006-045619 (Patent No. 4725051) Japanese Unexamined Patent Publication No. 2013-0533339 (Patent No. 5741944)

In the discharge method for circulation of the plating solution in Patent Document 1, an annular plating extraction portion made of a porous material, which is set on the base member (bottom) of the plating tank together with the cathode electrode, is a treatment liquid as described above. Has a structure that allows the material to pass through but does not pass through the object to be plated, and serves as a filter (porous ring filter).

However, in recent years, the miniaturization of electronic components that are the objects to be plated in plating equipment has been progressing, and in the case of porous filters with innumerable minute holes of several μm to several mm, the objects to be plated and energization A lot of media etc. are sandwiched. Therefore, the plating solution does not circulate in the plating apparatus, and there is a possibility that problems such as non-adhesion of plating may occur. In addition, there is a problem that the plated material once sandwiched between the filters falls off, and problems such as non-plating and abnormal plating frequently occur. Furthermore, it is assumed that the sandwiched plated material is gradually plated to close minute holes, making it difficult to circulate and discharge the plating solution itself, and the plating device does not function in a short time. ..

Further, like the plating apparatus of Patent Document 2, a configuration in which a plating solution overflows a tubular member provided in the center of a rotating body, flows into the tubular member, is discharged, and is returned to the plating processing chamber. Then, since the electronic component to be plated is small, it floats on the liquid surface due to buoyancy, and there is a problem that the electronic component is discharged together with the discharge of the plating solution.

The present invention has been made in view of the above-mentioned problems, and by efficiently discharging the plating solution from the plating tank, electrons that reduce plating defects such as thickness variation of the plating film formed on the chip-shaped electronic component. It is an object of the present invention to provide a plating apparatus for parts.

As one means for achieving such an object and solving the above-mentioned problems, for example, the following configuration is provided. That is, in the plating apparatus for electronic parts of the present invention, the object to be plated and the plating solution are stored in an internal space formed by a substantially conical lid portion and a substantially disk-shaped bottom portion having an outer peripheral side wall, and the plating solution is stored in the horizontal direction. A rotatable plating tank, an anode electrode arranged substantially in the center of the plating tank, a cathode electrode exposed on the inner peripheral side of the plating tank and forming a part of the outer peripheral side wall, and a lid. The portion is provided with an opening for discharging the plating solution, and the opening is provided with a tubular member that protrudes to the outside of the lid portion into a through hole provided in the lower portion of the inclined side surface of the lid portion. and wherein the Rukoto such Te.

For example, the opening is formed by inserting a tubular member projecting to the outside of the lid into a through hole provided in the lower portion of the inclined side surface of the lid and providing a net-like member covering the through hole. It is characterized by. For example, a plurality of the openings are provided at intervals in the circumferential direction of the lower portion of the lid portion . Further, for example, by changing the height of the outer peripheral side wall, the vertical position of the opening in the plating tank can be adjusted.

Further, for example, the tubular member is characterized in that it projects to the outside of the lid portion in a direction substantially perpendicular to the inclined side surface at a lower portion of the inclined side surface of the lid portion. Further, for example, the tubular member is characterized in that it can be pulled out from the through hole and replaced.

According to the present invention, by providing an opening at a position where the object to be plated does not come into direct contact with the object to be plated when the plating tank is rotated, it is possible to prevent the object to be plated from being pinched or left behind, and to circulate or discharge the plating solution and washing water. It is possible to perform a uniform plating process on the object to be plated without causing any trouble.

It is a perspective view which shows the structure by breaking a part of the plating apparatus of the electronic component which concerns on embodiment of this invention. It is sectional drawing which shows the detailed structure of the opening for discharging the plating solution provided in the lid part of the plating tank of the plating apparatus which concerns on this Embodiment example. It is a figure which shows the other structural example of the opening provided in the lid part of a plating tank. It is a figure which shows the arrangement example of the opening provided in the lid part of the plating tank of the plating apparatus which concerns on this Embodiment example. It is a figure which shows typically the circulation route of the plating solution and the like in the plating apparatus which concerns on this Embodiment example. It is a figure which shows the cross-sectional structure of the chip-like resistor which formed the plating layer on the external electrode.

Hereinafter, an example of an embodiment according to the present invention will be described in detail with reference to the accompanying drawings and the like. FIG. 1 is a perspective view showing a structure of a part of the plating apparatus for electronic components according to the present embodiment. The plating apparatus 10 shown in FIG. 1 is a rotary type in which an internal space composed of a lid portion 11 having a substantially conical outer shape and a bottom portion 13 arranged on the bottom surface side of the lid portion 11 is used as a plating tank 15. It is a plating device (dome type plating device).

The lid portion 11 has a protrusion 26 in which the peripheral edge portion (outermost outer peripheral portion) of the lowermost end of the inclined side surface projects in a brim shape in the outer peripheral direction, and the protrusion 26 is covered with an annular ring member 29. There is. Further, an opening 20 for discharging the plating solution and the like stored in the plating tank 15 is provided in the lower portion of the inclined side surface of the lid portion 11. The details of the opening 20 will be described later.

The bottom portion 13 is a disk-shaped bottom plate (base member) 18 having the same outer diameter as the outer diameter of the outermost outer peripheral portion of the lid portion 11, and is arranged along the outer peripheral edge portion on the upper surface side of the bottom plate 18 and is constant. A ring-shaped cathode electrode (cathode contact) 17 having the width of the above, and a spacer which is located above the cathode electrode 17 and below the protrusion 26 of the lid portion 11 and is an annular member having the same diameter as the cathode electrode 17. It is configured to have a ring 19. In the plating tank 15, the outer peripheral side wall 28 is formed by the outer peripheral edge portion of the bottom plate 18, the cathode electrode 17, the spacer ring 19, and the protrusion 26.

The ring member 29, the protrusion 26, the spacer ring 19, and the cathode electrode 17 are provided with a plurality of through holes in the circumferential direction thereof. Then, in a state where these are overlapped, the fixing member 27 is inserted into the through hole, and the male screw portion provided at the tip portion of the fixing member 27 and the female screw portion provided on the bottom plate 18 are screwed together. The lid portion 11 and the bottom portion 13 are fixed to each other. The internal space formed by the lid portion 11 and the bottom portion 13 serves as the plating tank 15.

The spacer ring 19 can be removed from the plating tank 15 by releasing the screwing by the fixing member 27. Therefore, by preparing spacer rings 19 having different thicknesses according to the charging conditions of the product (object to be plated) in the plating apparatus 10, the height of the outer peripheral side wall 28 described above can be changed, and as a result, the height of the outer peripheral side wall 28 can be changed. The volume of the plating tank 15, the position of the opening 20 (height from the bottom plate 18), and the like can be adjusted. Further, the drainage capacity of the plating tank 15 can also be adjusted by appropriately setting the size and number of the openings 20.

An anode electrode 16 to be immersed in the plating solution is arranged in the center of the plating tank 15, and water washing water is introduced to reach the center of the plating tank 15 through the upper opening 24 provided at the top of the lid 11. A pipe 21, a treatment liquid introduction pipe 22, and a liquid level sensor 23 for detecting the amount of plating liquid in the tank are provided. In the plating apparatus 10, as will be described later, the water washing water introduction pipe 21, the treatment liquid introduction pipe 22, and the like efficiently circulate and discharge various treatment liquids.

A rotation shaft 12 extending vertically downward is connected to the center portion on the lower surface side of the bottom portion 13, and the rotation shaft 12 is rotatably supported. Here, by applying a rotational force to the rotating shaft 12 with a motor or the like (not shown), the object to be plated 25 such as an electronic component and the plating tank 15 in which the plating solution (not shown) is stored are in the horizontal direction. Rotate to. Specifically, as shown by the white arrows in FIG. 1, the plating tank 15 repeatedly rotates and stops at a predetermined speed by rotating in the clockwise direction and the counterclockwise direction (forward and reverse directions). The rotating shaft 12 is connected from the negative side of the power source for electrolytic plating, and a conductive member 14 for energizing the cathode electrode 17 is in contact with the rotating shaft 12.

The plating tank 15 alternately repeats forward rotation and reverse rotation in the horizontal direction, the rotation is maintained, and as shown in FIG. 1, the object to be plated is pressed against the cathode electrode 17 by centrifugal force, and the anode is used only for a short time. processing Ki Tsu because is energized between electrode 16 and the cathode electrode 17 is performed.

The target of plating of electronic components by the plating apparatus according to the present embodiment is not limited to chip-type resistors, and for example, chip-type inductors, chip-type capacitors, composite components thereof, multiple resistors, etc. It can also be used for plating electronic components that have electrode terminals.

FIG. 2 is a cross-sectional view showing a detailed structure of an opening for discharging the plating solution, which is provided on the lid of the plating tank in the plating apparatus according to the present embodiment. As shown in FIG. 2, the opening 20 is a through hole provided in the lower part of the inclined side surface 11a of the lid portion 11 at a position where the object to be plated 25 does not come into direct contact when the plating tank 15 rotates in the horizontal direction. It consists of 33. Here, the hole diameter D of the opening 20 is set to, for example, 3 mm or more, but the present invention is not limited to this.

The liquid level (liquid level) of the plating solution 30 in the plating tank 15 is the plating tank when the plating tank 15 is stationary before the plating treatment or immediately after the completion of the plating treatment, and during the plating treatment or the cleaning treatment. When 15 is rotating, it is located in the vicinity of the upper opening 24 of the plating tank 15 (liquid level 31a in FIG. 2). At this time, the plating liquid 30 is discharged from the opening 20 to the outside of the plating tank 15, but since a new plating liquid is supplied to the plating tank 15 via the treatment liquid introduction pipe 22 by the circulation route described later, the liquid There is no change in the position of the surface 31a. On the other hand, at the stage where the plating treatment or the like is completed and dehydrated (discharged), the plating liquid 30 is discharged to the outside from the opening 20, and the supply of the plating liquid from the treatment liquid introduction pipe 22 is stopped. Lowers to the vicinity of the upper surface of the bottom plate 18 (liquid level 31b in FIG. 2).

In the example shown in FIG. 2, the opening 20 is composed of only the through hole 33 formed in the lid portion 11, but the opening portion 20 is not limited to this. For example, as shown in the opening 20a shown in FIG. 3A, a hollow pipe (tube) 35 having a hole diameter D of, for example, 3 mm, which is made of metal, fluororesin, or the like, is attached to the through hole 33 and is a part of the hollow pipe 35. May be configured such that H = 3 to 5 mm is projected to the outside of the lid portion 11. By doing so, when the plating tank 15 rotates, even if the object to be plated 25 comes into contact with the lower end of the through hole 33 and pops out, the object to be plated is captured by the hollow pipe 35 having a predetermined length, and moreover. Since the hollow pipe 35 is made of a material having a low friction coefficient and is inclined, the captured object to be plated is returned to the inside of the plating tank 15 again, so that the outside of the plating tank of the object to be plated is not reduced in drainage efficiency. It can effectively prevent the scattering to. Further, since the hollow pipe 35 is projected to the outside of the lid portion 11, it can be easily pulled out when the hollow pipe is replaced or the like.

On the other hand, the opening 20b shown in FIG. 3B has a configuration in which the through hole 33 is covered with a net-like member 37 inside the lid 11 with respect to the opening 20a shown in FIG. 3A. .. The net-like member 37 is made of, for example, a fluororesin, and has a mesh that allows the plating solution to easily pass through, but does not allow, for example, a minute object to be plated of 1 mm or less to pass through. As a result, even when the object to be plated 25 comes into contact with the opening of the through hole 33, the net-like member 37 prevents the object to be plated from entering the pipe 35, so that the object to be plated is scattered to the outside of the plating tank 15. Can be reliably prevented.

That is, by providing the lid portion 11 of the plating tank 15 with an opening portion 20b in which a net-like member 37 is stretched in the through hole 33 as shown in FIG. It is possible to prevent the soaring product and the like from leaking to the outside of the plating tank 15 together with the plating solution.

When the opening 20b shown in FIG. 3B is produced, a net-shaped member 37 having a size exceeding the hole diameter of the through hole 33 is prepared, and the net-shaped member 37 is placed on the outside of the through hole 33 (cover portion 11). The hollow pipe 35 is inserted into the through hole 33 together with the net-like member 37 while being in contact with the outside). By doing so, the net can be stretched so as to cover the entire through hole 33 without exposing the end portion of the net-like member 37 to the inside of the plating tank 15. Further, the net-like member 37 can be easily replaced by pulling out the hollow pipe 35 from the through hole 33.

FIG. 4 shows an example of arranging an opening provided in the lid when the plating tank of the plating apparatus according to the present embodiment is viewed in a plan view. FIG. 4A is an example in which a plurality of openings 20 are provided at equal intervals in the circumferential direction of the lower portion of the inclined side surface of the lid portion 11. Further, FIG. 4B shows an example in which a plurality of openings 20 are provided so as to be symmetrical with respect to the center line 41 in the circumferential direction of the lower portion of the inclined side surface of the lid portion 11. The hole shape of the opening 20 may be either circular or elliptical.

In the example shown in FIG. 4A, the six openings 20 are arranged at equal intervals, but for example, the number of openings is increased or decreased according to the size of the plating tank, the required amount of drainage, and the like, and these are arranged. It may be arranged at random intervals. Further, a plurality of lids may be prepared in which the hole diameter of the openings, the number of openings, and the spacing between the openings are appropriately changed according to the size of the plating target and the input amount.

FIG. 5 schematically shows a circulation route of a plating solution or the like in the plating apparatus according to the present embodiment. In the plating apparatus 10 shown in FIG. 5, when the plating solution is discharged from the opening 20 provided in the lid portion 11 as the plating tank 15 rotates, at the same time, a new plating solution in the plating solution mother tank 51 introduces the treatment liquid. It is supplied to the plating tank 15 via the tube 22. Further, the plating liquid discharged from the opening 20 is received by the container 50 that covers the entire outside of the plating tank 15, and reaches the plating liquid mother tank 51 via the treatment liquid outlet pipe 42.

When the treatment liquid is discharged due to the change of the plating type in the plating apparatus 10, the plating tank 15 is rotated at a high speed in a predetermined direction, and the plating liquid or the like is discharged from the opening 20 by utilizing the centrifugal force at that time to discharge the plating liquid or the like from the opening 20 to the container. Receive at 50.

In the water washing step of the plated product, water washing water is supplied from the water washing water tank 53 into the plating tank 15 via the water washing water introduction pipe 21, and the water washing water after washing is also discharged in the same manner as when the treatment liquid is discharged. Is rotated at high speed and the centrifugal force is used. Then, the water-washed water received in the container 50 is returned to the water-washed water tank 53 via the water-washed water outlet pipe 41.

Since the metal concentration in the plating tank 15 gradually decreases due to the electrolytic reaction in the plating process in the plating apparatus 10, the plating solution is constantly circulated between the plating tank 15 and the separately provided plating solution mother tank 51. Will be Therefore, if the treatment liquid and the washing water are not reliably circulated and discharged, various plating quality problems occur due to current abnormality during plating, mixing of each treatment liquid, and the like.

Next, the evaluation result of the plating quality of the chip resistor plated by using the plating apparatus according to the present embodiment will be described with reference to the examples. Here, the film thickness (μm) of the Ni (nickel) plating layer and the film thickness (μm) of the Sn (tin) plating layer were measured for Examples 1 to 5 of the lot quantity shown in Table 1. The film thickness of each plating layer was measured with the number of samples n = 20.

The Ni plating layer and the Sn plating layer are two plating layers constituting an external electrode in the chip resistor having a cross-sectional structure illustrated in FIG. 6, and usually, an end face electrode was formed in the manufacturing process of the chip resistor. After that, a Ni plating layer is formed, and Sn plating is performed on the Ni plating layer to form a Sn plating layer.

The plating solution used to form the plating layer of the chip resistor in the plating process is Ni plating: Watt bath and Sn plating: Neutral bath. The objects to be plated are a 0603 size resistor chip and a φ0.55 mm medium for energization.

In the prototype example using the conventional plating apparatus, it was confirmed that the object to be plated was caught in the plating tank (porous ring) and the number of residues after washing with water was about 20 to 30. On the other hand, in the prototype example of the chip resistor plated by using the plating apparatus according to the present embodiment (Examples 1 to 5 in Table 1), the number of objects to be plated was 0. rice field. Further, in the prototype example using the conventional plating apparatus, a large number of unplated products (non-plated products) which are considered to be caused by being caught in the porous ring were found, whereas the plating according to the embodiment of the present embodiment was performed. In the prototype using the device, there were no unplated products, and the difference between the maximum and minimum film thickness was small, so good results were obtained with regard to the variation in plating film thickness.

As described above, in the plating apparatus for electronic components according to the embodiment of the present embodiment, the object to be plated does not come into direct contact with the inclined side surface of the lid portion constituting the plating layer even if the plating layer rotates. By providing the opening, it is possible to prevent the object to be plated from being pinched or left behind, and it is possible to efficiently and surely discharge only the plating solution and the washing water. That is, even if the plating tank rotates in the horizontal direction and the objects to be plated move to the end of the plating tank due to centrifugal force and are pressed against the inner wall, an opening is provided at a position where the objects to be plated do not overlap with the objects to be plated. Therefore, a uniform plating process can be performed on the object without hindering the circulation and discharge of the plating solution and the like.

In addition, the height of the outer peripheral side wall can be adjusted by changing the thickness of the spacer ring that constitutes the bottom of the plating layer, so that the opening is vertical in the plating tank according to the conditions for loading the object to be plated. The position in the direction and the volume of the plating tank can be adjusted quickly.

Further, the plating apparatus for electronic components according to the embodiment of the present embodiment provided with the above-mentioned opening does not require a strong structure and mounting unlike the conventional porous filter ring, and the configuration of the plating apparatus is simplified. Not only can the treatment liquid be circulated and discharged efficiently, and the simple configuration can reliably prevent the occurrence of abnormal plating quality.

Further, when the opening is provided with a net-like member in the through hole inside the lid of the plating tank, regular maintenance such as net replacement can be performed easily and easily in a short time.

10 Plating device 11 Cover 12 Rotating shaft 13 Bottom 14 Conductive member 15 Plating tank 16 Anode electrode 17 Cathode electrode 18 Bottom plate (base member)
19 Spacer ring 20, 20a, 20b Opening 21 Water wash water introduction pipe 22 Treatment liquid introduction pipe 23 Liquid level sensor 24 Upper opening 25 Plated object 26 Projection 27 Fixing member 28 Outer peripheral side wall 29 Ring member 30 Plating liquid 31 Liquid level (Liquid level)
33 Through hole 35 Hollow pipe 37 Net-shaped member 41 Water wash water outlet pipe 42 Treatment liquid outlet pipe 50 Container 51 Plating liquid mother tank 53 Water wash water tank

Claims (6)

A plating tank that can rotate in the horizontal direction by storing the object to be plated and the plating solution in the internal space formed by the substantially conical lid and the substantially disk-shaped bottom having the outer peripheral side wall.
An anode electrode arranged substantially in the center of the plating tank and
A cathode electrode exposed on the inner peripheral side of the plating tank and forming a part of the outer peripheral side wall,
An opening provided in the lid for discharging the plating solution and
Equipped with a,
The opening, in a through hole provided on the inclined side surface lower portion of the lid, the plating apparatus for an electronic component, characterized in Rukoto such by inserting the tubular member protruding to the outside of the lid portion. The opening is characterized in that a tubular member projecting to the outside of the lid is inserted into a through hole provided in the lower portion of the inclined side surface of the lid, and a net-like member is provided to cover the through hole. The electronic component plating apparatus according to claim 1. The plating apparatus for an electronic component according to claim 1 or 2 , wherein a plurality of the openings are provided at intervals in the circumferential direction of the lower portion of the lid portion. The plating of an electronic component according to any one of claims 1 to 3, wherein the vertical position of the opening in the plating tank can be adjusted by changing the height of the outer peripheral side wall. Device. The method according to any one of claims 1 to 4, wherein the tubular member projects outward of the lid portion in a direction substantially perpendicular to the inclined side surface at a lower portion of the inclined side surface of the lid portion. Electronic component plating equipment. The electronic component plating apparatus according to any one of claims 1 to 5, wherein the tubular member can be pulled out from the through hole and replaced.

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