JP2008038240A - Method of plating chip-shaped electronic component - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plating method by which a plating film having optional and uniform thickness is formed on an external electrode of a chip-shaped electronic component. <P>SOLUTION: An anode 29 is arranged in a plating solution spray nozzle 25, the surface of the chip-shaped electronic component 11 is held by a holding means 20 to allow at least one external electrode 14 on the surface of the electronic component to face the nozzle in a state that the lower half of the surface of the electronic component is masked from the plating solution, a cathode probe 26 is brought into contact with a part of the external electrode of the electronic component and the plating solution is sprayed to the external electrode from the nozzle while applying voltage between the anode and the probe to plate the external electrode. After that, the cathode probe is brought into contact with the different position on the surface of external electrode to plate the surface of the external electrode again. As a result, the occurrence of unapplied part of the plating film in the vicinity of the contact position of the cathode probe in the surface of the external electrode of the chip-shaped electronic component is prevented to form the plating film having the optional and uniform thickness. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for plating a chip-shaped electronic component that forms a plating film on an external electrode of a chip-shaped electronic component used in various electronic devices, and more specifically, forms a plating film having an arbitrary uniform thickness on the external electrode. The present invention relates to a plating method.

  Barrel plating is generally used as a method for forming a plating film on the external electrode of a chip-shaped electronic component. In the above barrel plating method, a large amount of chip-like electronic components are inserted into the plating barrel together with conductive dummy particles, and the plating barrel is rotated while being immersed in the plating solution in the plating tank, and the inside of the plating barrel is agitated. On the other hand, a predetermined voltage is applied between the anode disposed in the plating tank and the cathode disposed in the plating barrel, and the chip is connected to the cathode via the conductive dummy particles. A plating film is formed on the surface of the external electrode of the electronic component.

  On the other hand, as a technique for forming a plating film at an arbitrary thickness on the surface of a metal substrate, for example, as disclosed in Patent Document 1, a plating method in which a plating solution is sprayed from a nozzle onto a metal substrate has been proposed. . Specifically, as shown in FIG. 4, the anode 129 is disposed in the plating solution spray nozzle 125, and the surface 111 to be plated is connected to the cathode 128 </ b> B, and a voltage is applied between the anode 129 and the cathode 111. In this state, the plating solution 123 is continuously sprayed.

Japanese Patent Application Laid-Open No. 09-263389

In recent years, various electronic devices have been increasingly miniaturized and thinned, and micro-sized chip-like electronic components used in these electronic devices, specifically 0.4 mm long × 0.2 mm wide (× height) A chip-shaped electronic component of 0402 size (0.2 mm or less) or an array type chip-shaped electronic component in which a plurality of elements are integrated has been proposed.
However, in the barrel plating method shown in the background art, when a plurality of external electrodes are provided at different positions on the surface of the electronic component such as an array type chip-shaped electronic component, the position and size of the external electrode In addition, there is a problem that a difference in the thickness of the plating film is likely to occur due to the connection resistance between the internal electrode and the external electrode of the electronic component element.
Further, for example, in the plating method in which a plating solution is sprayed as described in Patent Document 1, there is a problem that a difference in thickness of the plating film tends to occur concentrically with the front surface of the plating solution spray nozzle on the surface to be plated. It was.

  The object of the present invention is to solve the above-mentioned problems, and even in a chip-shaped electronic component having a plurality of external electrodes at different positions on the surface of a minute chip-shaped electronic component or electronic component, An object of the present invention is to provide a method for plating a chip-shaped electronic component capable of forming a plating film having an arbitrary uniform thickness.

In order to achieve the above object, the plating method for chip-shaped electronic components of the present invention comprises
(1) An anode is disposed in the plating solution spray nozzle, and an arbitrary position on the surface of the chip-shaped electronic component is held by the holding means so that the spray nozzle faces the at least one external electrode on the surface of the chip-shaped electronic component. Holding and contacting a cathode probe to an arbitrary position of the surface of the external electrode of the chip-shaped electronic component, and applying the voltage between the anode of the spray nozzle and the cathode probe, the spray nozzle and the chip-shaped electron Plating is performed by spraying a plating solution on the external electrode so that the plating solution is continuous with the external electrode of the component, and a cathode probe is brought into contact with a position different from the above on the surface of the external electrode of the chip-shaped electronic component. And then plating again. (... Hereinafter referred to as the first problem solving means of the present invention.)

One of the main forms of the plating method is
(2) Re-plating while holding a different position on the surface of the chip-shaped electronic component. (... Hereinafter referred to as the second problem solving means of the present invention.)

One of the other main forms of the plating method is
(3) Plating in a masked state so as to surround the contact position of the cathode probe. (... Hereinafter referred to as the third problem solving means of the present invention.)

One of the other forms of the plating method is as follows:
(4) The plating is performed with the holding means masking the periphery of the contact position of the cathode probe. (... Hereinafter referred to as the fourth problem solving means of the present invention.)

One of the other forms of the plating method is as follows:
(5) The plating solution is sprayed with a nozzle having an opening area larger than the exposed area of one external electrode of the chip-shaped electronic component. (... Hereinafter referred to as the fifth problem solving means of the present invention.)

  The operation of the first problem solving means is as follows. That is, an anode is disposed in the plating solution spray nozzle, and an arbitrary position on the surface of the chip-shaped electronic component is held by the holding means so that the spray nozzle is opposed to at least one external electrode on the surface of the chip-shaped electronic component. The spray nozzle and the chip-shaped electronic component while contacting a cathode probe at an arbitrary position on the surface of the external electrode of the chip-shaped electronic component and applying a voltage between the anode of the spray nozzle and the cathode probe The plating solution is sprayed onto the external electrode so that the plating solution is continuous with the external electrode, and then the cathode probe is brought into contact with a position different from the surface of the external electrode of the chip-like electronic component. Since plating is performed again, an unattached portion of the plating film is generated near the contact position of the previous cathode probe on the surface of the external electrode of the chip-shaped electronic component. That the can be prevented.

  The operation of the second problem solving means is as follows. That is, since the position different from the above on the surface of the chip-shaped electronic component is held and plating is performed again, an unattached portion of the plating film is generated in the vicinity of the previous holding position on the surface of the external electrode of the chip-shaped electronic component. Can be prevented.

  The operation of the third problem solving means is as follows. That is, since plating is performed in a masked state so as to surround the contact position of the cathode probe, it is possible to prevent a plating film from being directly formed on the cathode probe and thereby reducing the plating efficiency.

  The operation of the fourth problem solving means is as follows. That is, since plating is performed in a state where the periphery of the contact position of the cathode probe is masked by the holding means, the chip-like electronic component can be held without providing a separate holding means in addition to the masking means. Since an arbitrary region of the surface of the external electrode of the chip-shaped electronic component is covered with the masking means, a plating film having a uniform thickness can be formed even using a plating solution spray nozzle having a relatively small opening area.

  The operation of the fifth problem solving means is as follows. That is, since the plating solution is sprayed with a nozzle having an opening area larger than the area of one external electrode of the chip-like electronic component, it is possible to prevent the thickness of the plating film from locally increasing on the external electrode.

According to the chip-shaped electronic component plating method of the present invention, it is possible to prevent the occurrence of a non-deposited portion of the plating film in the vicinity of the contact position of the previous cathode probe on the surface of the external electrode of the chip-shaped electronic component. A plating film having a uniform thickness can be formed.
The above object and other objects, structural features, and operational effects of the present invention will become apparent from the following description and the accompanying drawings.

  Hereinafter, a first embodiment of a plating method for chip-shaped electronic components of the present invention will be described with reference to FIGS. 1 and 2. FIG. 1 is a conceptual diagram showing the overall structure of a plating apparatus 10 used in the plating method of the first embodiment. FIG. 2 is an enlarged cross-sectional view of a main part showing a region A surrounded by a chain line in FIG. 1 for explaining the plating method of the first embodiment using the plating apparatus 10. ) Shows a state in which a plated film is formed on the surface of the external electrode that holds the lower half of the surface of the chip-shaped electronic component and is exposed to the upper half, and FIG. 2B shows the chip-shaped electronic component 11 thereafter. This shows a state in which the plating film 15 is formed on the surface of the external electrode 14 that holds the upper half of the surface and is exposed to the lower half.

  As shown in FIG. 1, an example of the plating apparatus 10 used in the chip-like electronic component plating method of the present embodiment includes a box-shaped plating chamber 21, a tank 22 for storing a plating solution 23, and a cathode in the plating chamber 21. And a power supply 28 for applying a voltage between the anode and the anode. More specifically, inside the plating chamber 21 are a holding means 20 for holding the chip-shaped electronic component 11 and a pair of plating solution spray nozzles 25 for spraying the plating solution 23 to the chip-shaped electronic component 11. Is arranged. A tank 22 is disposed below the plating solution outlet of the plating chamber 21. The plating solution 23 in the tank 22 is stirred by the stirring means 22A if necessary, and the plating solution 23 is sprayed in the plating chamber 21 via the plating solution supply means 24 having a pipe 24A and a pump 24B. Sprayed from the nozzle 25 toward the chip-shaped electronic component. Next, as shown in FIG. 2, the holding means 20 for holding an arbitrary position on the surface of the chip-shaped electronic component 11 includes the external electrodes on both end surfaces and both side surfaces of the chip-shaped electronic component 11 in the length direction. It has a holding part 20A that covers an arbitrary area including a part and a support part 20B that supports the lower surface of the chip-shaped electronic component 11, and has an outer periphery excluding an end at a position facing the lower surface. A cathode probe 26 covered with the protection means 20C is disposed. One end of the cathode probe 26 is in contact with the surface of the external electrode 14 of the chip-like electronic component 11 held by the holding means 20, and the other end of the cathode probe 26 is a power source capable of adjusting the applied voltage. 28 cathode-side output terminals. An anode 29 is disposed inside the plating solution spray nozzle 25 so as to be exposed to the flow path of the plating solution 23, and the anode 29 is connected to the anode side output terminal of the power source 28.

The plating method of the first embodiment in which the plating film 15 is formed on the external electrode 14 of the chip-like electronic component 11 using the plating apparatus 10 as described above is a plating solution spray as shown in FIG. An anode 29 is disposed in the nozzle 25, the spray nozzle 25 faces the at least one external electrode 14 on the surface of the chip-shaped electronic component 11, and the lower half of the surface of the chip-shaped electronic component 11 is placed on the lower half. The cathode probe 26 is brought into contact with a part of the area masked from the plating solution 23 on the surface of the external electrode 14 of the chip-like electronic component 11 in a state masked from the plating solution 23, and While applying a voltage between the anode 29 of the spray nozzle 25 and the cathode probe 26, the spray nozzle 25 and the external electrode 14 of the chip-shaped electronic component 11 are applied. The plating solution 23 between the upper half exposed surfaces of plated by spraying the plating solution 23 to the external electrode 14 so as to be continuous.
Next, as shown in FIG. 2B, the upper half of the surface of the chip-shaped electronic component 11 different from the upper half is held in a masked state, and the surface of the external electrode 14 of the chip-shaped electronic component 11 is masked. The cathode probe 26 is brought into contact with a part of the masked region at a position different from the above, and the spray nozzle 25 and the tip shape are applied while applying a voltage between the anode 29 and the cathode probe 26 of the spray nozzle 25. Plating is performed again by spraying the plating solution 23 onto the external electrode 14 so that the plating solution 23 is continuous with the exposed surface of the lower half of the external electrode 14 of the electronic component 11.

  Further, in the present embodiment, as described above, plating is performed again while holding a position different from the above on the surface of the chip-shaped electronic component 11.

  Further, in the present embodiment, as described above, the plating is performed in a state of being masked from the plating solution 23 so as to surround the contact position of the cathode probe 26.

  In the present embodiment, as described above, plating is performed with the holding means 20 masking the periphery of the contact position of the cathode probe 26.

  In the present embodiment, the plating solution 23 is sprayed by the nozzle 25 having an opening area larger than the exposed area of one external electrode 14 of the chip-shaped electronic component 11. In the present embodiment, the upper half or the lower half of the surface of the external electrode 14 of the chip-shaped electronic component 11 that is not covered with the holding means 20 is exposed. For this reason, in the plating method of this embodiment, it is preferable that the opening area of the nozzle 25 is more than 1/2 of the area of the external electrode of the chip-shaped electronic component 11.

  Further, in the present embodiment, the flow rate of the plating solution 23 is 60 m / min. On the exposed surface of the external electrode 14 of the chip-shaped electronic component 11. It is preferable to spray the plating solution 23 as described above, whereby metal ions can be sufficiently supplied to the electrode interface, and concentration polarization of the plating solution can be suppressed.

  As the chip-like electronic component, an internal electrode 13 is disposed in a body 12 made of ceramic such as a dielectric material, a magnetic material, and other insulators, and is laminated and integrated by firing. However, the present invention is not limited to this, and the electrode is provided only on the surface of the element body without the internal electrode. A ceramic powder-containing resin composite material may be used instead of the ceramic body.

  The external electrode 14 of the chip-shaped electronic component 11 is generally provided when the element body 12 is formed, or is formed by baking so as to be connected to the internal electrode after the element body 12 is formed. However, the present invention is not limited to this and may be provided by other methods.

  In addition, the external electrodes 14 of the chip-shaped electronic component 11 are generally provided in the vicinity of both end surfaces in the axial direction of the element body 12 and the end surfaces on the upper surface, the lower surface, and the both side surfaces in contact therewith. However, the present invention is not limited to this, and may be provided at an arbitrary position on the surface of the chip-shaped electronic component 11.

  The pair of external electrodes 14 of the chip-shaped electronic component 11 is provided in the embodiment, but the present invention is not limited to this, and chip-shaped electronic components such as an array-type chip-shaped electronic component are not limited thereto. Three or more parts may be provided on the surface of the component.

  The plating film formed on the surface of the external electrode 14 of the chip-shaped electronic component 11 is generally a plating film made of a metal or alloy such as Ag, Cu, Ni, or Sn, but is not limited thereto. Instead, various other metals or alloys may be used.

  Further, as the plating film 15 formed on the surface of the external electrode 14 of the chip-shaped electronic component 11, any one type of plating film of the above metals or alloys is sequentially formed as a single layer or a plurality of types of plating films. You may overlap and form.

  The plating solution spray nozzle 25 has an anode 29 disposed therein, and the opening area of the nozzle is preferably larger than the exposed area of at least one external electrode of the chip-shaped electronic component facing the nozzle 25. Thereby, it is possible to prevent the plating film from being thickly formed only on a part of the exposed area of the surface of the external electrode 14 of the chip-shaped electronic component 11.

  The anode 29 preferably has a surface exposed to the flow path of the plating solution 23 in the nozzle 25.

  In the embodiment, the holding of the chip-shaped electronic component is to hold each part including the external electrodes on the peripheral side surface of the chip-shaped electronic component 11 and support the lower surface by the holding means 20. It is not limited, and the chip-like electronic component may be sandwiched between two opposing surfaces.

  The position where the chip-shaped electronic component 11 is held may be any position on the surface of the chip-shaped electronic component. In addition, when the holding position covers a part of the surface of the external electrode 14 in the surface of the chip-shaped electronic component, it is preferable to perform plating again while changing the holding position.

  The position where the cathode probe 26 contacts the surface of the external electrode 14 of the chip-shaped electronic component 11 may be any position on the surface of the external electrode 14, and the contact position of the cathode probe 26 is varied. Plating again is preferable.

  Masking is preferably performed on the surface of the external electrode 14 so as to surround the contact position of the cathode probe 26 so that the plating solution 23 is not in direct contact.

  In addition, it is preferable that the holding means is used in combination as a means for masking around the contact position of the cathode probe.

Next, the Example based on 1st Embodiment of the plating method of the chip-shaped electronic component of this invention using the said plating apparatus 10 is demonstrated. In this example, a so-called 1005 chip multilayer ceramic capacitor having a length of 1.0 mm, a width of 0.5 mm, and a height of 0.5 mm was used as the chip-shaped electronic component 11. The chip-shaped multilayer ceramic capacitor is opposed to the element body 12 made of a barium titanate-based high dielectric constant ceramic material so that the end portions of the internal electrodes 13 made of Ni are alternately exposed on both end faces of the element body 12. And both end surfaces and upper, lower, and both side surfaces in contact with the end surfaces so as to connect the ends of the plurality of internal electrodes 13 exposed at one and the other end surfaces of the element body 12, respectively. A pair of external electrodes 14 made of Ni is provided in the vicinity of each of the end faces. The wraparound dimension of the external electrodes 14 formed on the upper surface, the lower surface, and both side surfaces of the element body 12 is 0.25 mm from the end surface, and the area of each external electrode 14 is about 0.75 mm ^2. ing. Ni was used as the anode 29, a plating solution for Ni plating was used as the plating solution, and the plating solution spray nozzle 25 had a circular opening with a diameter of 0.7 mm. The voltage of the power source was adjusted so that the current density of the plating solution 23 continuous between the cathode probe 26 and the anode was 100 A / dm ² . The holding position and the contact position of the cathode probe were changed on the way, and then plating was performed again. A current was applied for a total of 7 seconds to form a Ni plating film 15 having a thickness of 1 μm.
Next, after the surface of the chip-shaped electronic component 11 is washed with pure water for 1 minute, Ag is used as the anode 29, and a plating solution for Ag plating is used as the plating solution. The voltage of the power source was adjusted such that the current density of the plating solution 23 continuous between the cathode probe 26 and the anode was 100 A / dm ² . In the middle, the holding position and the contact position of the cathode probe were made different, then plating was performed again, and a current was applied for a total of 4 seconds to form an Ag plating film having a thickness of 2 μm on the Ni plating film.
The Ni / Ag plating film obtained above was able to form a plating film for obtaining solder crease resistance and solder wet resistance.

  Next, a second embodiment of the chip-shaped electronic component plating method of the present invention will be described with reference to FIG. FIG. 3 is an enlarged cross-sectional view of a main part for explaining a plating method according to the second embodiment of the present invention. FIG. 3A shows a chip-shaped electronic component 31 that is first sandwiched by holding means 40 on the upper surface and the lower surface. First, the cathode probe 46 is brought into contact with the lower surface of the surface of the external electrode 34 of the chip-shaped electronic component 31, and the exposed surface of the external electrode 34 is plated except in the vicinity of the contact position of the cathode probe 46. FIG. 3B shows a state in which the film 35 is formed. Thereafter, the cathode probe 46 is brought into contact with the upper surface of the surface of the external electrode 34 of the chip-shaped electronic component 31, and the vicinity of the contact position of the cathode probe 46 is excluded. 2 shows a state in which a plating film 35 is formed on the surface of the external electrode 34 that is exposed.

The difference between the plating apparatus 30 used in the present embodiment and the plating apparatus 10 used in the first embodiment is that the holding means 40 that holds the chip-shaped electronic component 31 and the surface of the chip-shaped electronic component 31 are different. This is the arrangement and structure of the cathode probe 46 in contact with the external electrode.
Although the entire structure of the plating apparatus 30 used in this embodiment is not shown, the chip-shaped electronic component 31 is held on the upper and lower surfaces of the surface of the chip-shaped electronic component 31 where the external electrode 34 is not formed. It is held by being clamped by means 40.
The plating apparatus 30 used in the present embodiment has a cathode probe 46 and its masking means 47 provided independently of the holding means 40.
Further, the plating solution spray nozzle of the plating apparatus 30 used in the present embodiment has a larger opening than the nozzle used in the example of the first embodiment, and has a circular shape with a diameter of 1.0 mm.
Since other configurations and operational effects are the same as those of the plating apparatus 10 used in the first embodiment, the description thereof is omitted.

The present invention is not limited to the first and second embodiments, and some or all of the means of the respective embodiments can be used in combination.
In the above-described embodiment, the chip-shaped multilayer ceramic capacitors are plated one by one. However, the present invention is not limited to this, and a large number of chip-shaped electronic components can be simultaneously processed.

In the above embodiment, the chip-shaped multilayer ceramic capacitor is shown as the chip-shaped electronic component. However, the present invention is not limited to this, and is applicable to a chip-type thermistor, a chip-shaped inductor, and other various chip-shaped electronic components. Can do.
In the above embodiment, a single-element chip-shaped electronic component having a pair of external electrodes is shown as the chip-shaped electronic component. However, the present invention is not limited to this, and a plurality of electronic component elements are provided. The present invention can also be applied to a multi-terminal chip electronic component such as an array type chip electronic component or a composite chip electronic component including a plurality of types of electronic component elements.
In the above embodiment, a rectangular chip-shaped electronic component is shown as the chip-shaped electronic component. However, the present invention is not limited to this, and a winding inductor using a drum-shaped core, and other various shapes. It can be applied to chip-shaped electronic components.

  The present invention is suitable for forming a plating film on an external electrode of a chip-shaped electronic component used in various small and thin electronic devices.

It is a conceptual diagram for demonstrating the whole structure of the plating apparatus used for 1st Embodiment of the plating method of the chip-shaped electronic component of this invention. It is a principal part expanded sectional view which shows the area | region of A enclosed with the dashed-dotted line in FIG. 1 for demonstrating the plating method of the said 1st Embodiment. It is a principal part expanded sectional view for demonstrating the plating method of the 2nd Embodiment of this invention. It is sectional drawing which shows an example of background art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10: Plating apparatus 11: Chip-shaped electronic component 12: Element body 13: Internal electrode 14: External electrode 15: Plating film 20: Holding means 21: Plating chamber 22: Tank 23: Plating solution 24: Plating solution supply means 25: Nozzle 26: Cathode probe 28: Power source 29: Anode 30: Plating device 31: Chip-shaped electronic component 32: Element body 33: Internal electrode 34: External electrode 35: Plating film 40: Holding means 43: Plating solution 45: Nozzle 46: Cathode Probe 47: Masking means 49: Anode

Claims (5)

  An anode is disposed in the plating solution spray nozzle, and an arbitrary position on the surface of the chip-like electronic component is held by the holding means so that the spray nozzle faces the at least one external electrode on the surface of the chip-like electronic component, A cathode probe is brought into contact with an arbitrary position on the surface of the external electrode of the chip-shaped electronic component, and a voltage is applied between the anode of the spray nozzle and the cathode probe, and the outside of the spray nozzle and the chip-shaped electronic component. Plating is performed by spraying a plating solution onto the external electrode so that the plating solution is continuous with the electrode, and further, the cathode probe is brought into contact with a different position on the surface of the external electrode of the chip-like electronic component to perform plating again. A method for plating a chip-like electronic component, comprising:   The method for plating a chip-shaped electronic component according to claim 1, wherein the plating is performed again while holding a position different from the position on the surface of the chip-shaped electronic component.   2. The chip-shaped electronic component plating method according to claim 1, wherein plating is performed in a masked state so as to surround a contact position of the cathode probe.   The plating method for a chip-shaped electronic component according to any one of claims 1 to 3, wherein plating is performed in a state where the periphery of the contact position of the cathode probe is masked by the holding means.   The plating method for a chip-shaped electronic component according to any one of claims 1 to 3, wherein the plating solution is sprayed with a nozzle having an opening area larger than an exposed area of one external electrode of the chip-shaped electronic component. .

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