JP3273187B2 - Manufacturing method of wiring board - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a wiring board, and more particularly to a method for electrolytically plating a large number of external connection terminals provided on a wiring board using a rectangular insulating substrate having a plurality of layers.

[0002]

2. Description of the Related Art A ceramic package 1 having many lead pins (external connection terminals) 2, such as a pin grid array type ceramic package shown in FIGS. 1A and 1B, has a large number of lead pins in a manufacturing process. 2
Need to be plated with a metal such as nickel (Ni) or gold (Au). In this plating step, it is necessary to conduct all the many lead pins 2 which are insulated from each other.

Conventionally, as a means for establishing conduction in common with a large number of lead pins 2, a lead-out wiring layer 4 extending from each of the lead pins 2 through the inside of the ceramic substrate 3 to the surface of the side surface 5 of the ceramic substrate 3 is formed. A common conductor layer 6 is formed on the surface of the side surface 5 of the ceramic substrate 3 by using a printed wiring method or the like, and the lead-out wiring layer 4 exposed on the surface of the side surface 5 is commonly connected by the common conductor layer 6.

With such a configuration, as shown in FIG.
By connecting the common conductor layer 6 to a predetermined potential by the conducting arm 7, it is possible to keep all of the many lead pins 2 at the same potential, so that the surface of the insulated lead pin 2 can be easily electroplated. To form a plated metal layer. Further, after the completion of the plating step, by removing the common conductor layer 6, a large number of lead pins 2 can be insulated from each other again.

[0005]

However, since the common conductor layer 6 needs to be connected by a conductive arm,
In order to ensure conduction between the conduction arm and the common conductor layer 6, it was necessary to make the width of the common conductor layer 6 wider (see FIGS. 3A and 3B). However, when the width of the common conductor layer 6 is increased in this manner, a large amount of plating metal is deposited on the surface of the common conductor layer 6, so that the waste of the plating metal increases and the manufacturing cost increases. .

The present invention has been devised in view of the above-mentioned drawbacks, and has as its object to reduce the waste of plated metal while ensuring the conduction between the common conductor layer 6 and the conduction arm 7 and to reduce the manufacturing cost. It is an object of the present invention to provide a method of manufacturing a wiring board which can reduce the number of wiring boards.

[0007]

According to a first aspect of the present invention, there is provided a method of manufacturing a wiring board, comprising a plurality of external connection terminals provided on a surface of a rectangular insulating substrate. Forming a lead-out wiring layer leading to each side of the rectangular insulating substrate from each of the plurality of external connection terminals; and forming a common conductor layer having a partially wide portion on each side of the rectangular insulating substrate. Attaching and electrically connecting the lead-out wiring layer, energizing a wide portion of the common conductor layer,
A method of manufacturing a wiring board, comprising: a step of forming a plated metal layer on the surfaces of the plurality of external connection terminals by an electrolytic plating method; and a step of polishing each side surface of the rectangular insulating substrate to remove a common conductor. Is the gist.

According to the present invention, the vicinity of the portion to be energized in the common conductor layer is widened, so that the connection with the conductive arm or the like can be ensured. Furthermore, since the width of the portion of the common conductor layer that is not connected to the conductive arm is reduced, the amount of plating metal deposited on the common conductor layer can be reduced, and the waste of plating metal can be minimized.

When there are a plurality of conductive arms for connecting to the common conductor layer on each side surface for more securely holding the wiring board, at least one of the plurality of conductive arms is connected to the common conductor layer. Therefore, it is sufficient that only the portion of the common conductor layer that is connected to at least one of the plurality of conductive arms be widened.

Further, in order to make the common conductor layers formed on the respective side surfaces conductive with each other, a connection conductor layer extending to each adjacent side surface inside each corner of the rectangular insulating substrate is formed. The continuity between them can be further ensured.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. First, a raw material powder of aluminum oxide, silica, calcia, magnesia, or the like is formed into a slurry by adding and mixing an appropriate organic solvent and a solvent, and is formed into a sheet by using a doctor blade method, a calendar roll method, or the like. Thereby, a ceramic green sheet (ceramic green sheet) is obtained. Thereafter, the ceramic green sheets are subjected to a suitable punching process to form a rectangular shape, thereby obtaining a predetermined number of rectangular ceramic green sheets.

The thus obtained rectangular ceramic green sheet 23 includes, for example, a wiring metallization layer 28 which becomes a desired signal wiring layer after firing, and a signal wiring formed on a different insulating layer after firing, as shown in FIG. In addition to forming a via 29 serving as a via conductor for connecting layers and the like to each other,
After the firing, a derived metallized layer 24 to be the derived wiring layer 14 is formed. A part of the derived metallization layer 24 is led to each side surface 25 of the ceramic green sheet 23. Further, the connection metallization layer 20 led out to the side surface 25 adjacent to each corner of the upper surface of the ceramic green sheet 23 becomes a connection wiring layer after firing, and is formed on each side surface 15 of the rectangular insulating substrate 13 described later. Conductive layer 16
Function to conduct each other.

Next, the ceramic green sheet 23 and a predetermined number of other ceramic green sheets are stacked one above the other to form a ceramic green sheet laminate 30. Each side surface 35 of the ceramic green sheet laminate 30
Then, a side metallization layer 26 is formed (see FIG. 5). The side metallization layer 26 includes a wide portion 26a having a width wider than the others at substantially the center in the longitudinal direction.

The wiring metallization layer 28, the via 29,
Derived metallization layer 24 and side metallization layer 26
Are, for example, tungsten (W), molybdenum (M
o), made of a high melting point metal powder such as manganese (Mn),
A metal paste obtained by adding and mixing an appropriate organic solvent, solvent and the like to the high melting point metal powder is formed by employing a conventionally well-known screen printing method.

Next, the ceramic green sheet laminate 3
0 is fired at about 1600 ° C. in a reducing atmosphere, and the ceramic green sheets are sintered and integrated to form an insulating substrate 11. At this time, the wiring metallization layer is a signal wiring layer, the via is a via conductor, the derived metallization layer is the derived wiring layer 14, the side metallization layer 26 is the common conductor layer 16, the connection metallization layer 2
0 becomes a connection wiring layer. Note that the common conductor layer 16 has a wide portion 16a wider than other portions at substantially the center in the longitudinal direction. Further, the lead pin 12 is brazed to a brazing pad formed on the surface of the insulating substrate 11 via a brazing material such as silver brazing to form a wiring board 11 (FIG. 6A).
reference).

Next, as shown in FIG. 6B, the conductive arm 17 is brought into contact with the wide portion 16a, and a plating metal layer is deposited on the surfaces of the lead pins 12 and other predetermined portions. In this plating step, specifically, the wiring board 11 is immersed in a plating solution, and the conductive arm 17 is connected to the common conductor layer 16.
This is performed by applying a constant power to the lead pins 12 and the like via the.

In this case, each of the lead pins 12 is connected to the common conductor layer 1 by the lead-out wiring layer 14 and the connection wiring layer.
6, the common conductor layer 1
When power is applied to the lead 6, power for electrolytic plating can be applied to all the lead pins 12, and a plating metal layer can be formed on the exposed outer surfaces of many lead pins 12 at once. Examples of the plating metal include nickel and gold, but other metals may be used.

In the above-mentioned plating step, a plating metal is also deposited on the surface of the common conductor layer 16. However, since the width of the common conductor layer 16 other than the wide portion 16 a is narrow, unnecessary plating is performed. Metal layering can be minimized. The width of the common conductor layer 16 other than the wide portion 16a is determined by the printing accuracy or the like when the common conductor layer 16 (side metallization layer 26) is formed in order to ensure conduction with the derived wiring layer exposed on the side surface 15. May be determined in consideration of
The range of 4 mm to 1.0 mm is preferable, and in the present embodiment, it is 0.7 mm.

Further, since the conduction arm 17 is brought into contact with the wide portion 16a of the common conductor layer 16, conduction between the two can be ensured. As the width of the wide portion becomes wider, the contact with the conducting arm 17 becomes easier. However, it does not make sense to make the width wider than a certain value, and the plated metal may be wasted. An appropriate width should be selected in consideration of the shape, size, and the like. 1.0mm ~
A range of 2.0 mm is preferable, and in this embodiment, 1.6 m
m.

Further, the width of the wide portion and other portions is
It is preferably at least 0.2 mm. If the amount is less than that, the effect of reducing the waste of the plating metal becomes small.

Then, the side surface 15 of the rectangular insulating substrate 13 is polished by a mechanical polishing device such as a grinder.
By removing the common conductor layer 16, each lead pin 2
And the lead-out wiring layer 14 are electrically independent, and the wiring board is completed. An electronic component such as a semiconductor element is mounted on such a wiring board. Although not described in detail in the above embodiment, a conventionally known structure necessary for mounting a semiconductor element or the like can be provided.

The rectangular insulating substrate 11 is made of an electrically insulating material such as a sintered body of aluminum oxide, a sintered body of mullite, a sintered body of aluminum nitride, and a sintered body of silicon carbide.
The lead pins 12 are made of Kovar (Fe-Ni-Co).
Alloys) and 42 alloys (Fe-Ni alloys). A predetermined pin shape is obtained by employing a conventionally known metal working method such as a rolling method or a punching method for an ingot (lumps) such as Kovar metal. Formed.

In the above embodiment, the common conductor layer 16 having the shape shown in FIG. 6 is formed. However, the present invention is not limited to this shape. For example, the shape shown in FIGS. Good. That is, the rectangular insulating substrate 31 shown in FIG.
Have wide portions 36 a protruding on both sides of the common conductor layer 36. The rectangular insulating substrate 41 shown in FIG. 7B has wide portions 46a protruding on both sides of the common conductor 46, and the wide portions 46a are substantially oval. FIG.
The rectangular insulating substrate 51 shown in (c) includes two wide portions 56 a protruding on one side of the common conductor layer 56. This ensures contact with the two conductive arms. 7 (a) to 7 (c), only the main parts are shown, and the lead pins and the like are omitted.

A plurality of conductive arms may be provided for each side surface. The more conductive arms, the easier and more reliable the holding of the wiring board. In this case, at least one of the plurality of conductive arms may correspond to the wide portion. That is, it is not necessary to provide a wide portion in a portion corresponding to all the conductive arms.

In order to facilitate the holding of the wiring board, a conductive arm is brought into contact with a common conductor layer on one set of two sides of the four sides of the rectangular insulating substrate, and the conductive arm is It is good to hold a wiring board. In this case, the wide portion may be provided only on the common conductor layer on the two sides that are in contact with the conductive arm. However, when sandwiched by the conductive arm, the side (side) provided with the wide portion is confirmed. Therefore, it is necessary to attach the wiring board to the conduction arm. Therefore, even when the conductive arm is brought into contact with the common conductor layer on the side surface of one set of two opposing sides of the four sides of the rectangular insulating substrate, and the wiring substrate is sandwiched between the conductive arms, even if
A wide portion may be provided on the side, that is, on the common conductor layer on all side surfaces. According to such a configuration, it is not necessary to check the direction of the wiring board when attaching the wiring board to the conductive arm, so that the work of attaching the wiring board to the conductive arm becomes easy.

It should be noted that the present invention is not limited to the above-described embodiment, and various changes can be made without departing from the gist of the present invention. In particular, various shapes can be considered for the shape of the wide portion of the common conductor layer. Further, the form of the wide portion may be appropriately changed for each side surface.

[0027]

According to the method of manufacturing a wiring board of the present invention,
While ensuring conduction between the common conductor layer and the conduction arm,
The plating metal deposited on the common conductor layer can be minimized, and the manufacturing cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a diagram showing a conventional method for manufacturing a wiring board;
(A) is a perspective view of a main part, and (b) is a cross section of the main part.

FIG. 2 is a cross-sectional view of a main part showing a conventional method of manufacturing a wiring board, showing a state where a common conductor layer 6 and a conductive arm 7 are connected.

FIG. 3 is a diagram showing a conventional method for manufacturing a wiring board;
(A) is a perspective view of a main part, and (b) is a cross section of the main part.

FIG. 4 is a diagram illustrating a method for manufacturing a wiring board according to an embodiment of the present invention, and is a plan view of a ceramic green sheet.

FIG. 5 is a diagram illustrating a method for manufacturing a wiring board according to an embodiment of the present invention, and is a diagram illustrating a ceramic green sheet laminate 30.

6A and 6B are diagrams illustrating a method for manufacturing a wiring board according to an embodiment of the present invention, wherein FIG. 6A is a perspective view of a main part, and FIG.

FIG. 7 is a view showing a modification of the method of manufacturing a wiring board according to the embodiment of the present invention, wherein (a) to (c) show different forms of the common conductor layer.

[Explanation of symbols]

 1, 11: Wiring board 2, 12: Lead pin 3, 13: Rectangular insulating substrate 4, 14: Derived wiring layer 5, 15: Side surface 6, 16 ,: Common conductor layer 16a: Wide portion 7, 17: Conductive arm

Claims (1)

(57) [Claims] 1. A method for manufacturing a wiring board, comprising a plurality of external connection terminals provided on a surface of a rectangular insulating substrate, wherein each side surface of the rectangular insulating substrate is formed from each of the plurality of external connection terminals. Forming a lead-out wiring layer to be led out, and applying a common conductor layer having a partially wide portion to each side surface of the rectangular insulating substrate, and electrically connecting the lead-out wiring layer; Energizing a wide portion of the common conductor layer to form a plated metal layer on the surfaces of the plurality of external connection terminals by electrolytic plating, and polishing each side surface of the rectangular insulating substrate to remove the common conductor. And a method for manufacturing a wiring board.