JP3078795B1 - Wiring board plating method and plating jig used therefor - Google Patents

Abstract

A method of forming a plating layer on a terminal or the like of a ceramic wiring board having a common conductor layer on a side surface by electrolytic plating without causing a decrease in holding power of the wiring board. Reduce waste of plated metal. SOLUTION: A wiring board 100 is formed by a plating jig 1.
In order to maintain the electrical conductivity and establish electrical continuity with the common conductor layer 105 for electrolytic plating, the plating jig 1
And elastic holding part 11 for elastically holding
In addition to the holding portion, a conductive portion 21 having a spring property and elastically contacting the common conductor layer 105 is provided. Holder 1
1 to elastically hold the wiring board 100,
1 is elastically brought into contact with the common conductor layer 105 to establish conduction for electrolytic plating.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for plating a wiring board, and more particularly, to exposing terminals and the like of a ceramic wiring board (IC package) used for mounting (sealing) electronic components such as semiconductor elements. The present invention relates to a method for forming a plating layer on a metal layer (wiring layer) by electrolytic plating (electroplating).

[0002]

2. Description of the Related Art A metal layer including terminals for connecting semiconductor elements and terminals for external connection in a wiring board of this kind is made of a high melting point metal such as tungsten or molybdenum, and is a ceramic green sheet on which the same metal paste is printed. Laminated,
It is formed by pressing and simultaneous firing. Metal layers such as each terminal and wiring layer can be brazed,
In order to prevent oxidation (corrosion), a nickel plating layer is usually formed, and a gold plating layer is further formed thereon.

In order to form such a plating layer by electrolytic plating (hereinafter simply referred to as plating), a plating jig 1 as shown in FIGS. That is, the plating jig 1 has a ladder shape, and from the bases 3 on both sides thereof, a holding conductive portion having a spring property for holding and conducting the wiring board 100.
(Arms) 31 are provided corresponding to the number of wiring boards 100 to be set (three in FIG. 4). At the time of plating, the wiring board 100 is elastically held by the holding conductive portions 31. Then, the plating jig 1 holding the wiring board in this manner is hung on a plating hanger 111 connected to a cathode, immersed in a plating solution 120 in a plating tank 115 and applied, so that the terminals 103 and the like are applied. Then, a plating layer is formed.

In the wiring board (hereinafter also simply referred to as a board) 100 shown in FIG.
Further, a common conductor layer (metal layer) 105 is formed so as to be continuous with the internal wiring layer 03 and an internal wiring layer (not shown).
Incidentally, the substrate 10 on which the plating layer was formed as described above was used.
A value of 0 means that each wiring is made independent by removing the common conductor layer 105 by polishing (grinding) or the like in a later step.

By the way, in order to achieve stable conduction with such a plating jig (hereinafter simply referred to as a jig) 1, it is necessary that reliable contact between the holding conductive portion 31 and the common conductor layer 105 be obtained. It is. For this reason, in the above-mentioned conventional jig 1, a metal wire (metal rod) having a thickness larger than necessary is used for the holding conductive portion 31 only from the point of conduction.

[0006]

However, if the holding conductive portion 31 is thick as in the conventional jig 1 as described above, the useless plating metal attached to the holding conductive portion 31 increases. Therefore, in particular, plating of a noble metal such as gold plating causes an increase in the cost of the wiring board.
On the other hand, if the holding / conducting portion 31 is formed of a thin metal wire, the holding force is reduced, leading to instability of conduction, making it impossible to supply a stable voltage and current, and further causing a risk of uneven plating and plating failure. Will be higher. In the electroplating, in order to eliminate waste of plating, the holding conductive portion 31 is located at a position near the tip thereof in contact with the common conductor layer 105 and in the vicinity thereof (hereinafter also referred to as a contact portion) 32.
Except for the above, the coating may be covered with the insulating layer 35 so as not to be plated. However, there is still a problem that the holding conductive portion 31 is large and the plating metal is wasted much.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and it is possible to reduce the waste of plating metal to be deposited without lowering the holding force of a wiring substrate to be plated in electrolytic plating. It is in.

[0008]

In order to achieve the above object, a method of plating a wiring board according to the present invention is to form a plating layer on a terminal or the like of a ceramic wiring board having a common conductor layer on a side face by electrolytic plating. In the forming method, when the wiring board is held by a plating jig and conduction is established for the electrolytic plating with the common conductor layer, the plating jig includes an insulating property and a spring for elastically holding the wiring board. Holding part having a property, separately from the holding part, a conductive part having a spring property that elastically contacts the common conductor layer is provided,
The wiring portion may be elastically held by the holding portion, and the conductive portion may be elastically contacted with the common conductor layer to establish conduction for electrolytic plating. Here, the common conductor layer refers to a conductor layer (metal layer) that is formed so as to be commonly conductive when forming a plating layer on each terminal or the like of the wiring board by electrolytic plating.

In the present invention, the holding portion and the conducting portion of the plating jig are provided separately as in the above-mentioned means. Therefore, the holding portion is made thick and the entire surface is insulated, while the conducting portion is made thin. Since the insulation treatment can be performed except for the contact portion, without lowering the holding power of the wiring board,
Moreover, waste of the plated metal to be deposited can be reduced. Therefore, according to the present invention, it is possible to reduce waste of precious metals such as gold plating without causing plating defects.

[0010] In the present invention, an insulating layer is formed on the surface of the conductive portion except for a portion in contact with the common conductor layer and the vicinity thereof, and useless plating metal adhered to the conductive portion is reduced as much as possible. It is preferable to do so. In such an aspect of the invention, it is preferable that the holding portion is formed of a metal wire and an insulating layer on the surface, and the conduction portion is formed of a metal wire thinner than the metal wire of the holding portion.

The present invention also includes a plating jig used in the above method. That is, the wiring board is held for forming a plating layer by electrolytic plating on terminals of a ceramic wiring board having a common conductor layer on the side surface, and the common conductor layer and the conduction for electrolytic plating are taken. A holding part having an insulating property and a spring property for elastically holding the wiring board, and a spring property for elastically contacting the common conductor layer separately from the holding part. And a conductive portion having the same.

In the plating jig of the present invention, it is preferable that the conductive portion has an insulating layer formed on the surface except for a portion in contact with the common conductor layer and the vicinity thereof. Further, in such a plating jig, it is preferable that the holding portion is formed of a metal wire and a surface insulating layer, and the conduction portion is formed of a metal wire thinner than the metal wire of the holding portion.

[0013]

1 to 3 show an embodiment of the present invention.
This will be described in detail with reference to FIG. FIG. 1 shows a wiring board 100 which is an object to be plated by a plating jig 1 according to the present invention.
FIG. 4 is a perspective view of a main part in a state in which the device is held and is electrically connected to the common conductor layer 105 on the side surface. The wiring board 100 in the figure is formed in a substantially square plate shape.
On one main surface, terminals 103 and die attach portions connected to electrodes of the IC chip to be mounted are formed, and on four side surfaces, a common conductor layer 105 is formed. It is connected.

The plating jig 1 according to the present embodiment, like the conventional plating jig 1, has a ladder formed by connecting bases 3 formed of square bars arranged on both sides substantially in parallel with each other at a proper position by a connecting portion 5. For example, it is formed of a stainless alloy,
It is formed to hold a plurality of wiring boards 100. However, the base 3 and the connecting portion 5 are coated with a resin on the surface to form an insulating layer 6.

In this embodiment, in order to hold one wiring board 100, two pairs of holding portions made of a metal wire (for example, a stainless steel wire) 10 and having an appropriate spring property are provided substantially vertically from the left and right bases 3. Numerals 11 extend substantially parallel to each other, and the vicinity of the distal end is bent outward to form a curved shape. In this manner, the side portions of the wiring substrate 100 can be elastically sandwiched by the curved portions 12 of the pair of holding portions 11 opposed to each other in the upper and lower directions. However, the entire surface of the holding unit 11 is coated with a resin, and the insulating layer 15 is formed on the surface. An outwardly inclined portion 16 is provided at the end of the curved portion 12 at the tip of the holding portion 11,
In holding (mounting) the wiring board 100, it serves as a guide when the wiring board 100 is pushed toward the jig 1.

On the other hand, a metal wire (stainless-alloy wire) thinner than the holding portion 11 is provided substantially at the center of the upper and lower holding portions 11 corresponding to the wiring board 100, like the holding portion 11, from the base (metal) 3. A conductive portion 21 extending substantially vertically and parallel is formed in a protruding shape. However, the leading end of the conducting portion 21 is curved so as to project inward, opposite to the holding portion 11.
In the state where the wiring board 100 is held by the upper and lower holding parts 11 as shown in FIGS. It is formed so as to elastically contact the common conductor layer 105. In the present embodiment, the surface of the conductive portion 21 is coated with resin in the same manner as the base 3 and the like except for the curved portion 22 at the distal end, and the insulating portion 25 is provided.

When a plating layer is formed on the terminals 103 of the wiring board 100 using the plating jig 1 of the present embodiment, a predetermined number of wiring boards 10
2 is pressed between the holding portion 11 and the curved portions 12 and 22 of the conducting portion 21 in the free state shown by the two-dot chain line in FIGS. Then
The holding portion 11 and the conducting portion 21 are bent outward and expanded by their spring properties, and the side surface of the wiring board 100 is fitted into the curved portion 12 of the holding portion 11 and held (mounted) on the jig 1. At the same time, the curved portion 22 of the conductive portion 21 elastically contacts the common conductor layer 105 of the wiring board 100. In this way, the wiring board 100 is held in conduction with the plating jig 1.

Thereafter, the jig 1 in that state is hooked on a hanger connected to the cathode in the same manner as in the prior art, and is suspended and dipped in a plating solution in a plating tank and applied. A plating layer is formed on the metal layer exposed such as the common conductor layer 105 and the conduction of the common conductor layer 105 is maintained.

In such a plating step, the jig 1
Since the holding portion 11 for holding the wiring board 100 is made of the thick metal wire 10, the wiring board 100 can be stably held, and since the holding portion 11 is insulated, the plating metal does not adhere. . Further, since the curved portion 22 of the conductive portion 21 is thin and only the metal is exposed only in the curved portion 22 which is in contact with the common conductor layer 105, the plating metal is not applied to a portion other than the wiring board 100 in the conventional art. It can be reduced compared to the plating process. Thus, the waste of the plated metal can be reduced as much as possible, including the case of plating a noble metal such as gold.

In the plating jig 1 of the present embodiment, the holding parts 11 for holding one wiring board 100 are provided in two pairs, so that the holding stability is excellent. It is sufficient that 100 can be held, and the number and arrangement may be appropriately determined. Further, the holding portion 11 has the insulating layer 15 formed on the surface of the metal wire 10. However, the holding portion 11 only needs to have a spring property and an insulating property. Therefore, the material of the entire holding portion 11 is formed of a nonmetal such as plastic. You may. Further, the shape of the holding portion 11 is only required to be able to hold the wiring board, and is not limited to the above-described embodiment.

The conductive portion is formed of the common conductor layer 1 as in this embodiment.
It is preferable to coat an insulating material such as a resin except for a portion that comes into contact with the part 05. In this case, it is preferable to reduce the surface area of the exposed metal in order to reduce the waste of the plated metal, as long as it does not hinder the conduction. Further, in the above description, the conductive portions 11 corresponding to one wiring board 100 are provided as a pair of left and right so as to be in contact with the common conductor layer 105 on both opposing side surfaces of the wiring board 100. Not necessarily. It suffices that conduction with the common conductor layer of the wiring board is maintained. Therefore, for example, when all of the common conductor layers 105 of the wiring board 100 in the above-described embodiment are continuous, it is possible to provide one conduction portion. . The plating jig of the present invention may be embodied by appropriately changing the design according to the number of wiring boards to be held, the size of the wiring boards, and the like.

The pattern (planar shape) of the common conductor layer of the wiring board is a portion where the conductive portion of the plating jig contacts (a portion near the center of the side surface of the substrate illustrated in FIG. 1) in order to ensure conduction. Is preferably as wide as possible. On the other hand, the portion of the common conductor layer where the conductive portion does not contact is preferably made as narrow as possible in order to reduce the waste of the plating metal to be deposited. Even when the common conductor layers are provided on the four side surfaces of the wiring board, it is preferable that the common conductor layers are not provided independently, but are connected to each other inside the wiring board, for example, near the corners of the side surfaces.
Further, the present invention is not limited to the above-described wiring board, and is applicable to electrolytic plating of wiring boards such as various IC packages having a common conductor layer.

[0023]

As is apparent from the above description, the present invention has the following effects. That is, since the holding portion and the conducting portion of the plating jig are provided separately, the holding portion is thickened and the entire surface is insulated, while the conducting portion is thinned and the insulating portion is removed except for the contact portion. You can keep
It is possible to reduce the waste of the plating metal to be deposited without lowering the holding power of the wiring board. As described above, according to the present invention, it is possible to reduce the waste of noble metal such as gold plating without causing plating failure, and therefore, it is expected that the manufacturing cost of the wiring board is reduced.

[Brief description of the drawings]

FIG. 1 is an explanatory view of an embodiment of a plating method according to the present invention, and is a perspective view of a main part in a state where a wiring board is held by a plating jig.

FIG. 2 is an enlarged view seen from above in FIG.

FIG. 3 is an enlarged central plan sectional view of the wiring board in FIG. 1;

FIG. 4 is an explanatory view illustrating a conventional plating method, in which a wiring board is attached to a plating jig, hung and hung on a hanger, and immersed in a plating tank.

FIG. 5 is a perspective view of a main part in FIG. 5;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Plating jig 10 Metal wire forming a holding portion 11 Holding portion 15 Insulating layer of holding portion 21 Conducting portion (metal wire) 22 Contact portion of contact portion with common conductor layer and its vicinity 23 Insulating layer of conducting portion 100 Ceramic Wiring board 105 common conductor layer

Claims (6)

(57) [Claims] In a method of forming a plating layer on a terminal or the like of a ceramic wiring board having a common conductor layer on a side surface by electrolytic plating, the wiring board is held by a plating jig, and the common conductor layer and the common conductor layer are connected to each other. In order to establish conduction for plating, the plating jig has an insulating and spring-like holding portion for elastically holding the wiring board, and aside from the holding portion, the common conductive layer has an elasticity. A conductive portion having a spring property is provided so as to be in contact therewith, and the wiring portion is elastically held by the holding portion, while the conductive portion is elastically brought into contact with the common conductor layer for electrolytic plating. A plating method for a wiring board, wherein the plating is conducted. 2. The method for plating a wiring board according to claim 1, wherein the conductive portion is formed by forming an insulating layer on the surface except for a portion in contact with the common conductor layer and the vicinity thereof. 3. The holding part according to claim 1, wherein the holding part comprises a metal wire and a surface insulating layer, and the conduction part is formed by a metal wire thinner than the metal wire of the holding part. The plating method of the wiring board to be performed. 4. A method for forming a plating layer on a terminal of a ceramic wiring board having a common conductor layer on a side surface by electrolytic plating to hold a wiring board, and conducting the electroconductive plating with the common conductor layer. A jig for plating, which is used for removing the wiring board, and a holding portion having an insulating property and a spring property for holding the wiring board elastically; A plating jig provided with a conductive portion having a spring property in contact therewith. 5. The jig for plating a wiring board according to claim 4, wherein the conductive portion is formed by forming an insulating layer on the surface except for a portion in contact with the common conductor layer and the vicinity thereof. 6. The holding part according to claim 4, wherein the holding part comprises a metal wire and a surface insulating layer, and the conducting part is formed of a metal wire thinner than the metal wire of the holding part. Jig for plating.