JP2006028571A - Method for plating electronic component and method for manufacturing electronic component - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for plating electronic components for applying good plating at a good yield to the electronic components by suppressing and preventing occurrence of an adhesion defect of the cohesion of the electronic components to each other, and degradation in uniformity of plating films even when the plating is applied to the small-sized electronic components, and a method for manufacturing the electronic components using the method for plating electronic components. <P>SOLUTION: The electronic component (laminated ceramic capacitors) 10 has an approximately rectangular parallelepipe shape of 0.6 mm in length (L), 0.3 mm in width (W) and 0.3 mm in height (T), and in this case, as media 11 for current passage, the media of approximately spherical shapes having a diameter of 0.9 to 1.1 times of the shortest side size of the electronic component are used. Also, the plating is performed by further adding approximately spherical insulative granule (medium for agitation) 12 for loosening thereto. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a plating method used when plating an electronic component. Specifically, the electronic component and a current-carrying medium housed in a container equipped with a plating electrode are immersed in a plating solution, and the plating electrode is used. The present invention relates to a plating method for an electronic component in which the electronic component is plated by energization, and a method for manufacturing an electronic component using the same.

  One of typical chip-type electronic components is a multilayer ceramic capacitor as shown in FIG. This multilayer ceramic capacitor 60 is arranged such that a plurality of internal electrodes 53a, 53b are opposed to each other via a ceramic layer 52, and both ends of a ceramic element 51 with one end side alternately drawn to different end faces. On the side, a pair of external electrodes 54a and 54b are disposed so as to be electrically connected to the internal electrodes 53a and 53b. The external electrodes 54a and 54b are formed, for example, by applying, drying and baking a conductive paste containing Ag powder as a conductive component, and Ag electrodes are soldered on the surfaces of the external electrodes 54a and 54b. An Ni plating film 55 for preventing the above and an Sn plating film 56 for improving the solderability are formed.

  And, as a method of forming a plating film on the external electrode, there is a container plating method in which an electronic component and a current-carrying medium are put in a container equipped with a plating electrode, and plating is performed by vibrating the container while energizing the electrode. It is known (see Patent Document 1).

  In addition, the electronic component and the energizing medium are housed in a container equipped with a plating electrode, and vibration is applied to the electronic component by energizing the plating electrode while immersing the container in the plating solution and applying vibration. A plating method is also used (see Patent Documents 2 and 3).

  By the way, the plating method disclosed in Patent Document 1 solves problems such as plating growing on the plating electrode (cathode) in a dendritic manner, resulting in a decrease in plating efficiency and a variation in plating film thickness. Therefore, a medium having a diameter of 0.8 to 1.3 times the maximum dimension of the minimum projected area of the electronic component that is the object to be plated is used as the energization medium.

  Moreover, in the vibration plating method of Patent Document 2, a current-carrying medium having a diameter of 0.93 to 1.8 times the longest side dimension of an electronic component that is an object to be plated is used.

  Furthermore, in the vibration plating method of Patent Document 3, while preventing the occurrence of cracks and chips in the electronic component, the surface hardness is set so that the aggregation of the electronic component can be suppressed and plating can be performed reliably. There has been proposed a method using an insulating particle whose surface is covered with an insulating rubber or resin whose surface hardness is lower than that of an electronic component. Patent Document 3 discloses that the diameter of the insulating particles is not less than 5 times the minimum dimension of the outer shape of the electronic component and not more than 10 times the maximum dimension.

However, in the case of the above conventional plating method, for example, when trying to plate a small electronic component having a length of 0.6 mm or less, a width of 0.3 mm or less, and a height of 0.3 mm or less, If the size of the electronic component is small, the electronic components are aggregated during plating, and the electronic components are joined together, so-called sticking failure occurs, or the uniformity of the formed plating film is reduced. There is a problem.
JP-A-9-137296 JP 2002-129395 A JP 2003-73898 A

  The invention of the present application solves the above-mentioned problems, and even when plating is performed on small electronic components, the occurrence of sticking defects in which the electronic components are joined together and the uniformity of the plating film is reduced. It is an object of the present invention to provide a method for plating an electronic component capable of suppressing and preventing the above-described plating and performing good plating with a high yield and a method for manufacturing an electronic component using the plating method.

In order to solve the above problems, the plating method of the electronic component of the present invention (Claim 1)
In the plating method of an electronic component in which an electronic component housed in a container equipped with an electrode for plating and a current-carrying medium are immersed in a plating solution and the electronic component is plated by energizing the electrode for plating.
When the electronic component is an electronic component having a substantially rectangular parallelepiped shape having a length of 0.6 mm or less, a width of 0.3 mm or less, and a height of 0.3 mm or less,
As the energization medium, a substantially spherical energization medium having a diameter of 0.9 to 1.1 times the shortest side dimension of the electronic component is used.

  According to a second aspect of the present invention, there is provided a method for plating an electronic component, further comprising adding a substantially spherical insulating particle for unraveling to the container to perform plating.

  The electronic component plating method according to claim 3 is characterized in that the electronic component is plated by energizing the plating electrode while applying vibration to the container.

  Moreover, the manufacturing method of the electronic component of the present invention (Claim 4) includes a step of forming a plating film on the surface of the electrode disposed in the electronic component by the plating method according to any one of Claims 1 to 3. It is characterized by having.

  In the method of plating an electronic component according to the present invention (Claim 1), the electronic component is an electronic component having a substantially rectangular parallelepiped shape having a length of 0.6 mm or less, a width of 0.3 mm or less, and a height of 0.3 mm or less. In addition, as the energization medium, a substantially spherical energization medium having a diameter of 0.9 to 1.1 times the shortest side dimension of the electronic component is used. It is possible to suppress and prevent the occurrence of the above and the deterioration of the uniformity of the plating film, and to perform good plating with a high yield.

That is, by using a substantially spherical energization medium 0.9 to 1.1 times the shortest side dimension of the electronic component, even when the electronic component is small as described above, the energization medium and the electronic medium It becomes possible to ensure a sufficient contact probability between the parts. As a result, the plating distribution ratio to the electronic component (the ratio of the amount plated on the electronic component to the total plating amount on the electronic component, plating electrode, and energizing medium) is increased, and the plating film with the target film thickness It is possible to reduce the current density required to form the film, to suppress the sticking failure, and to increase the contact probability between the current-carrying media and the electronic component, thereby making the plating film uniform. Therefore, it is possible to efficiently plate fine electronic components having a length of 0.6 mm or less, a width of 0.3 mm or less, and a height of 0.3 mm or less.
Note that, as the energization medium, a substantially spherical energization medium having a diameter of 0.9 to 1.1 times the shortest side dimension of the electronic component is used because the diameter of the energization medium is the shortest of the electronic component. If the side dimension is less than 0.9 times, the electronic component element will be raised on the energizing medium, and plating will be performed at a high current density, and the occurrence rate of sticking defects in which the electronic components are joined together will be increased. Further, when it exceeds 1.1 times, the current density required for obtaining the target film thickness increases, and the occurrence rate of sticking defects that cause electronic components to be joined increases.
In the method of plating an electronic component according to the first aspect of the present invention, the plating is usually performed while stirring, swinging, vibrating, and the like in a state where the electronic component accommodated in the container and the energizing medium are immersed in the plating solution. However, in the invention of claim 1 of the present application, there are no particular restrictions on the method of giving agitation, oscillation, vibration, etc., and their modes.

  Further, as in the method for plating electronic parts according to claim 2, when plating is performed by further adding substantially spherical insulating particles for agitation (stirring medium) in the container, the aggregation of electronic parts ( Assembly) and agglomeration (aggregation) of electronic parts and current-carrying media, and it is more certain that sticking defects will occur, and the uniformity of the plating film will be reduced. It is possible to suppress and prevent electronic parts from being plated with good yield.

  Further, when the electronic component is plated by energizing the plating electrode while applying vibration to the container as in the method for plating an electronic component of claim 3, the electronic component is small as described above. Even if it is, it is possible to ensure a sufficient contact probability between the current-carrying medium and the electronic component, and increase the plating distribution ratio to the electronic component, so that a plating film with a target film thickness is obtained. It is possible to reduce the current density required to form the film and suppress the occurrence of sticking defects, and to improve the uniformity of the plating film, with a length of 0.6 mm or less and a width of 0 It is possible to efficiently and surely apply plating to minute electronic parts having a height of 3 mm or less and a height of 0.3 mm or less.

Moreover, the manufacturing method of the electronic component of the present invention (Claim 4) is such that a plating film is formed on the surface of the electrode disposed in the electronic component by the plating method according to any one of Claims 1 to 3. Therefore, for example, when Ni plating or Sn plating is applied to the external electrode formed on the surface of the electronic component, the occurrence of sticking defects that cause the electronic components to come together, and the uniformity of the plating film It is possible to suppress and prevent the occurrence of a decrease and to perform good plating with a high yield.
As a result, it is possible to efficiently manufacture a small and highly reliable electronic component.

  The features of the present invention will be described in more detail below with reference to examples of the present invention.

  In this example (Example 1), as shown in FIGS. 1A and 1B, the dimensions are length (L) 0.6 mm, width (W) 0.3 mm, and height (T) 0. The outer electrodes 4a and 4b (the Ni plating film 5 is formed on the surface) of the multilayer ceramic capacitor 10 having a substantially rectangular parallelepiped shape of 3 mm are subjected to Sn plating, and the Sn plating film 6 is formed on the surface of the Ni plating film 5. An example of forming the case will be described.

  As shown in FIGS. 1A and 1B, a multilayer ceramic capacitor (electronic component) 10 which is an object to be plated in Example 1 includes a plurality of internal electrodes 3a and 3b in a ceramic layer in a ceramic element 1. 2 and the internal electrodes 3a and 3b facing each other through the ceramic layer 2 are alternately drawn out to the end face on the opposite side of the ceramic element 1, and the external electrodes 4a and 4b formed on the end face It has the structure connected to.

  In Example 1, as shown in FIG. 1 (a), the multilayer ceramic capacitor 10 to be plated is a surface of external electrodes 4a and 4b formed by applying and baking a conductive paste. In this state, Ni plating 5 is applied.

Moreover, FIG. 2 is a figure which shows an example of the plating apparatus used in implementing the plating method of the plating electronic component concerning one Example of this invention.
This plating apparatus 20 accommodates a multilayer ceramic capacitor (electronic component) 10, an energizing medium 11 that functions as an energizing medium, and a loosening insulating granular material (agitating medium) 12, at least a part of which is a plating solution. A container 13 made of a material (for example, a wire mesh) that passes through, a driving means 14 for applying vibration to the container 13, a container whose lower end side holds the container 13, and whose upper end side is connected to the driving means 14 A holding member 15, a cathode (cathode electrode) 17 disposed on the bottom 16 of the container 13, an anode electrode 18, and a plating tank (Sn plating tank) 19 for containing a plating solution are provided.

Next, a method of performing Sn plating on the external electrodes 4a and 4b of the multilayer ceramic capacitor 10 using the above-described plating apparatus will be described.
First, 300,000 multilayer ceramic capacitors 10 having a length (L) of 0.6 mm, a width (W) of 0.3 mm, and a height (T) of 0.3 mm, and a diameter of 0.22 to 0.55 mm. 50 cc of energizing media 11 and 80 insulating particles 12 for loosening having a diameter of 7.5 mm are mixed and put into a container 13 equipped with a cathode electrode 17, and this is put into an Sn plating tank 19. Immerse.

In addition, as the energizing medium 11, a steel ball was used, and as shown in Table 1, the diameter was changed in the range of 0.22 to 0.55 mm.
In addition, as the loosening insulating particles (stirring medium) 12, a sphere made of iron whose surface was covered with an insulating material such as rubber was used.
The energizing medium is not limited to a steel ball, and various kinds of energizing media that are used as energizing media in a plating method in which an electronic component housed in a container and an energizing medium are immersed in a plating solution and are energized. It is possible to use a material made of these materials.

  Then, vibration is applied from the driving means 14 to vibrate the container 13, while stirring the multilayer ceramic capacitor 10, the energizing medium 11, and the loosening insulating particles 12 in the container 13, and the cathode electrode 17 of the container 13. Was applied to the external electrodes 4a and 4b of the multilayer ceramic capacitor 10 by Sn plating. In Example 1, the current density was changed so that an Sn plating film having a target plating film thickness of 3.5 μm was formed in 200 minutes.

And about the multilayer ceramic capacitor obtained by performing Sn plating as mentioned above, while investigating Sn plating film thickness, it investigated the incidence rate of the sticking defect which multilayer ceramic capacitors (electronic parts) join together. It was.
The results are shown in Table 1.

  In Table 1, the “sample number” column and the “ratio of the current-carrying media diameter to the electronic component shortest side dimension” marked with * are outside the scope of the present invention.

  As shown in Table 1, as the energization media, those having a diameter in the range of 0.9 to 1.1 times the shortest side dimension of the electronic component, such as sample numbers 6, 7, and 8, that is, the diameter is 0 It was confirmed that when the energization medium 11 in the range of .27 to 0.33 mm was used, the sticking failure rate was 0.05% or less.

  This is because by using a current-carrying medium whose diameter is in the range of 0.9 to 1.1 times the shortest side dimension of the electronic component, the agitation becomes good and the probability of contact with the electronic component increases, leading to the electronic component. As a result of the increase in the plating distribution ratio and the decrease in the current density for obtaining the target film thickness, it is considered that the occurrence rate of the sticking failure in which the electronic components are brought together is suppressed.

  On the other hand, when a medium whose diameter exceeds 1.1 times the shortest side dimension of the electronic component is used as the energization medium as in sample numbers 1 to 5, the current density necessary to obtain the target film thickness is It has been confirmed that the incidence of sticking defects in which electronic components are brought into contact with each other increases.

  In addition, even when a medium having a diameter of less than 0.9 times the shortest side dimension of the electronic component is used as in the case of sample numbers 9 and 10, there is no sticking failure in which the electronic components are brought together. It was confirmed that the incidence was high. This is considered to be due to the fact that the diameter of the current-carrying medium becomes too small, the electronic component element is raised on the current-carrying medium, and Sn plating is performed at a high current density.

  In this example (Example 2), using the same plating apparatus as in Example 1, the dimensions were length (L) 0.4 mm, width (W) 0.2 mm, and height (T). The outer electrode of the multilayer ceramic capacitor having a substantially rectangular parallelepiped shape of 0.2 mm was subjected to Sn plating.

  In addition, in performing Sn plating, 500,000 multilayer ceramic capacitors having a length (L) of 0.4 mm, a width (W) of 0.2 mm, and a height (T) of 0.2 mm and a diameter of 0.14 to 50cc of 0.40mm current-carrying medium and 80 insulating particles for loosening with a diameter of 7.5mm are mixed and put into a container equipped with a cathode, and this is immersed in a Sn plating tank and plated. did. The specific procedure of the plating method was the same as in Example 1 above.

And about the multilayer ceramic capacitor obtained by performing Sn plating as mentioned above, while investigating Sn plating film thickness, the incidence rate of the sticking defect which electronic components join together was investigated.
The results are shown in Table 2.

  In Table 2, the “sample number” column and the “ratio of the current-carrying medium diameter to the electronic component shortest side dimension” marked with * are outside the scope of the present invention.

  As shown in Table 2, the current-carrying medium 11 has a diameter in the range of 0.9 to 1.1 times the shortest side dimension of the electronic component, such as sample numbers 15, 16, and 17, that is, the diameter is It was confirmed that when the energization medium in the range of 0.18 to 0.22 mm was used, the sticking failure rate was 0.05% or less.

  As described in the case of Example 1 above, the use of a current-carrying medium having a diameter in the range of 0.9 to 1.1 times the shortest side dimension of the electronic component makes stirring good. Increasing the probability of contact with electronic components, increasing the plating distribution ratio to electronic components, and reducing the current density to obtain the target film thickness, resulting in sticking defects that cause electronic components to join together It is thought that the rate was suppressed.

  On the other hand, when a medium having a diameter exceeding 1.1 times the shortest side dimension of the electronic component is used as the energization medium as in sample numbers 11 to 14, the current density necessary to obtain the target film thickness is Increasingly, the occurrence rate of sticking defects in which electronic components are brought together increases.

  Further, even when a medium having a diameter of less than 0.9 times the shortest side dimension of the electronic component is used as in the case of sample numbers 18 and 19, there is no sticking failure in which the electronic components are brought together. Incidence increased. This is because, as described in the case of the first embodiment, the diameter of the current-carrying medium becomes too small, the electronic component element is raised on the current-carrying medium, and Sn plating is performed at a high current density. It is thought to be due to.

  In Examples 1 and 2, an example in which a Ni plated film is formed on the surface of an external electrode of a multilayer ceramic capacitor (ceramic element) is a component to be plated, and Sn plating is applied on the Ni plated film. As described above, there are no particular restrictions on the type of metal to be plated (Ni in Examples 1 and 2) and the type of metal to be plated (Sn in Examples 1 and 2). The present invention can be widely applied to the case where the plating is performed under various conditions such as the case where Ni plating is performed on the Ag electrode and the case where solder plating is performed on the Ni plating film.

  In the above embodiment, the case where the external electrode of the multilayer ceramic capacitor is plated has been described as an example. However, the present invention is not limited to the multilayer ceramic capacitor, but other electronic components (for example, chip resistor, chip coil, chip LC component). It can also be applied to the case of plating a chip thermistor, chip ferrite, etc.).

  In Examples 1 and 2, the electronic component (multilayer ceramic capacitor), which is the object to be plated, is plated with the energizing media and the loosening insulating particles (stirring media) in the container. However, it is also possible to perform plating without adding the insulating particles for agitation (stirring medium), and in this case, the same effects as those in Examples 1 and 2 can be obtained. it can.

  Further, in the above-described Examples 1 and 2, the case where an electronic component (multilayer ceramic capacitor) that is an object to be plated and a current-carrying medium are plated in a container having an upper surface opened has been described as an example. There is no special restriction in the configuration of the plating apparatus for carrying out the plating method of the electronic component of the invention, and the barrel plating method in which the component to be plated and the current-carrying medium are placed in a rotatable barrel and plating is performed while rotating the barrel. It is possible to apply the present invention also when using.

  The present invention is not limited to the above embodiment in other points, and various applications and modifications can be made within the scope of the invention.

When plating the surface of an electronic component having a substantially rectangular parallelepiped shape having a length of 0.6 mm or less, a width of 0.3 mm or less, and a height of 0.3 mm or less as in the method for plating an electronic component of the present invention, energization is performed. By using a substantially spherical energizing medium with a diameter in the range of 0.9 to 1.1 times the shortest side dimension of the electronic component, the electronic components will not stick together and the plating film uniformity will be reduced. It is possible to suppress and prevent the occurrence of the above and to perform good plating with a high yield, and it is possible to efficiently manufacture highly reliable small electronic components.
Therefore, the present invention can be widely used in, for example, a manufacturing process of a small electronic component having an external electrode provided with a plating film.

It is a figure which shows the electronic component (multilayer ceramic capacitor) plated by the plating method of the electronic component concerning Example 1 of this invention, (a) is sectional drawing, (b) is a perspective view. It is a figure which shows an example of the plating apparatus used in implementing the plating method of the plating electronic component concerning one Example of this invention. It is sectional drawing which shows the structure of the electronic component (multilayer ceramic capacitor) plated by the conventional plating method.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Ceramic element 2 Ceramic layer 3a, 3b Internal electrode 4a, 4b External electrode 5 Ni plating film 6 Sn plating film 10 Multilayer ceramic capacitor (electronic component)
11 Current-carrying media (metal ball media)
12 Stirring media (insulating granules for loosening)
DESCRIPTION OF SYMBOLS 13 Container 14 Drive means 15 Container holding member 16 Bottom of container 17 Electrode for cathode 18 Electrode for anode 19 Plating tank (Sn plating tank)
20 Plating equipment

Claims (4)

In the plating method of an electronic component in which an electronic component housed in a container equipped with an electrode for plating and a current-carrying medium are immersed in a plating solution and the electronic component is plated by energizing the electrode for plating.
When the electronic component is an electronic component having a substantially rectangular parallelepiped shape having a length of 0.6 mm or less, a width of 0.3 mm or less, and a height of 0.3 mm or less,
A plating method for an electronic component, wherein a substantially spherical energization medium having a diameter of 0.9 to 1.1 times the shortest side dimension of the electronic component is used as the energization medium.   The method for plating an electronic component according to claim 1, wherein plating is performed by further adding substantially spherical insulating particles for loosening into the container.   3. The electronic component plating method according to claim 1, wherein the electronic component is plated by energizing the plating electrode while applying vibration to the container.   A method for manufacturing an electronic component, comprising the step of forming a plating film on a surface of an electrode disposed on the electronic component by the plating method according to claim 1.

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