JPH03252193A - Wiring board - Google Patents

Abstract

PURPOSE:To prevent disturbance of mounting components other than electrodes and to prevent a decrease in disturbance removing effect by forming a through hole formed at a board or a first electrode on the inner surface of a hole, forming a dielectric on the upper surface of the electrode, and forming a second electrode on the dielectric. CONSTITUTION:A square or round through hole 20 is formed at a board 12, and a first electrode 13 made of a conductive material such as Cu, Ag, etc., is formed on the inner surface of the hole 20 and on the board 11 at upper and lower hole edges. The edges of the hole 20 are formed in smooth taper shape, and the electrode 13 is provided thereon. Further, dielectric 14 containing such as lead oxide, strontium is formed on the electrode 13 to provide a necessary designing capacitor capacity. Further, a second electrode 15 is so formed thereon as to hole the dielectric 14, and a capacitor 16 is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a wiring board with a built-in capacitor.

Conventional technology As shown in Figure 3, the conventional wiring board 1 with a built-in capacitor is
A first layer electrode 3 made of a conductive material such as Cu or Ag is formed on the surface of the substrate 2 through a film thickness printing process and a baking process, and furthermore, in order to have a designed capacitance on the top surface of the electrode 3. , the dielectric 4 is formed through a thick film printing process, a firing process, and the like. Then, electrodes 5 are formed through a thick film printing process, a firing process, etc. so as to sandwich the dielectric 4, and a capacitor 6 is constituted by these electrodes 3, 5 and the dielectric 4.

Furthermore, the upper surface of the electrode 5 is coated with an overcoat material 7 such as epoxy, phenolic resin, or glass for the purpose of protection against heat stress during soldering of the capacitor 6, stress caused by temperature, humidity, etc. in the market. is being carried out.

Problems to be Solved by the Invention In the wiring board 1 with a built-in capacitor as shown in FIG. When high-density mounting of components 9. IC, etc.) is required, this becomes a factor that impedes the mounting. Also, capacitor 6
As shown in Figure 3, in the case of a grounded capacitor for eliminating interference at the power supply terminal of high-frequency equipment, etc., the distance between the electrode 10 of the power supply terminal and the capacitor 6 is long, and the wiring becomes long, reducing the interference elimination effect by half. It turns out. SUMMARY OF THE INVENTION An object of the present invention is to solve these problems and prevent the mounting of other components from being obstructed and the interference elimination effect from decreasing.

Means for Solving the Problems In order to achieve this object, the present invention forms a first electrode on the inner surface of a through hole or hole provided in a substrate, and coats a dielectric material on the upper surface of the first electrode. A second electrode is formed on this dielectric.

By having a configuration that exceeds the functions, the first. Since the capacitor made of the second electrode and the dielectric material is formed in the thick part of the substrate, there is no spread in the lateral direction.

For this reason, input/output terminals and chip components to wiring boards.

Even when high-density mounting of various electronic components such as ICs is required, electronic components can be mounted at high density. In addition, for components with input/output terminals or lead wires, the second electrode of the capacitor can be used as the land for soldering the lead wires, which not only allows for even higher density mounting, but also allows for the soldering of the lead wires to the second electrode of the capacitor. In comparison, since it is a capacitor without a wiring part, it is possible to construct a high-performance capacitor with low ESR (high frequency resistance) and small variations, so that the interference elimination effect is not reduced.

EXAMPLE An example of the present invention will be described below with reference to the drawings. In FIGS. 1A and 1B, a substrate 12 such as a ceramic substrate or a printed circuit board is provided with a through hole 20 having a corner or a round shape. And this through hole 20
The inner surface and the upper and lower hole edges of the substrate 12 are coated with Cu and Ag.
The first electrode 13 made of a conductive material such as, for example, is formed by a thick film printing and baking method, or a mesoki method. Note that the upper and lower edges of the through hole 20 are gently tapered, and the first electrode 13 is provided thereon. Further, on the upper surface of the first electrode 13, a dielectric material 14 containing lead oxide, strontium, etc. is disposed on the upper surface of the first electrode 13 to provide the necessary design capacitance.
is formed by thick film printing and firing process. Further, a second electrode 15 is formed on the dielectric 14 so as to sandwich the dielectric 14 therebetween by a thick film printing and firing method, a plating method, or the like. With this process and structure, the capacitor 16
is formed. In addition, there are areas where an overcoat 17 of epoxy, phenolic resin glass, etc. is required for the purpose of protecting the wiring board 11 containing the capacitor 16 from heat stress caused by solder dipping, temperature, humidity, etc. in the market. coated with.

Since the capacitor 16 of the present invention can be formed into a capacitor in the form of a through-hole, as shown in FIG. can be directly soldered to the second electrode 15 of the capacitor 16.

Next, FIG. 2 (al, (b)) shows another embodiment of the present invention.
Explain with reference to. A long and narrow groove-shaped through hole 20 is formed in the substrate 12.
A first electrode 13 is formed on the right inner surface of this groove-shaped through hole 20, and the upper surface portion of the substrate 12 of this first electrode 13 serves as a land for connecting other components. A second electrode 15 is formed on the left inner surface of the groove-shaped through hole 20, and the upper surface of the substrate 12 is also a land. However, in this case, the first electrode 13 and the second electrode 15 are independent with no electrical connection.

By filling this elongated groove-shaped through hole 20 with the dielectric material 14 of the capacitor, the first electrode 13 and the second electrode
A capacitor 16 is configured between electrodes 15.

In this case as well, the upper and lower edges of the through hole 20 are gently tapered, and the first and second holes are formed on the upper and lower edges of the through hole 20. Second electrode 13.1
5 is formed.

Further, in the above embodiment, the through hole 20 that penetrates the substrate 12 is formed, but this hole is made halfway through the substrate, and the first through hole 20 is formed here. A second electrode 13.15 may also be provided.

Effects of the Invention As described above, since the present invention forms the capacitor in the thick part of the board, high-density mounting of various electronic parts such as input/output terminals, chip parts, and ICs on the board is not hindered. Become. In particular, for input/output terminals and components with lead wires, the land can be used as the land for soldering the lead wires, and the electrodes in the through holes or holes can also be used. This also makes it possible to achieve high-density mounting. Therefore, the ESR (high frequency resistance) is small, and the interference elimination effect is not reduced.

[Brief explanation of drawings]

FIGS. 1(a) and (bl) are a cross-sectional view and a bottom view of a wiring board according to an embodiment of the present invention, and FIGS. 2(a) and (b) are a cross-sectional view and a plan view of another embodiment of the present invention. , FIG. 3 (al, (bl is a sectional view and bottom view of a conventional example. 11... Wiring board, 12... Board, 1
3...First electrode, 14...Dielectric material,
15... Second electrode, 16... Capacitor, 17... Overcoat, 20...
・Through hole.

Claims (2)

[Claims] (1) forming a first electrode on the inner surface of a through hole or hole provided in the substrate; forming a dielectric on the upper surface of the first electrode;
A wiring board characterized in that a second electrode is formed on the dielectric. (2) Forming electrically independent first and second electrodes in a through hole provided in the wiring board or on the inner surface of the hole,
A wiring board in which the through hole or the hole is filled with a dielectric material.