JPH0388392A - Multilayer printed wiring board - Google Patents

Abstract

PURPOSE:To reduce wiring pattern by performing electrical connection using a jumper wire crossing the other wiring pattern in a region crossing one wiring pattern which actually crosses the main surface of the main body of a wiring board. CONSTITUTION:The title item has a multi layer printed wiring board main unit 1, wiring patterns 1a and 1b which are formed in a form actually crossing on the main surface of this multi-layer printed wiring board main body 1, and a jumper wire 3. Then, the jumper wire 3 is bonded through a bonding pad 4 which is provided at the edge part of the wiring pattern 1a which is provided sandwiching one wiring pattern 1b, thus performing electrical connection between the wiring patterns 1a. In this case, since no through-holes are used for connecting the wiring patterns 1a and 1b at the crossing region, the inner-layer wiring pattern layer can be used for other signals, thus achieving high-density wiring and miniaturization of the multilayer printed wiring board 1.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a multilayer printed wiring board, and more particularly to a multilayer printed wiring board with an improved electrical connection method between wiring patterns.

(Prior Art) As is well known, multilayer printed wiring boards, which are formed by laminating and integrating signal wiring pattern layers, power supply wiring pattern layers, grounding wiring pattern layers, etc., are widely used in various electronic devices. It is put into practical use.

Incidentally, this type of multilayer printed wiring board has a configuration in which electrical connections between wiring pattern layers are made by through-hole connections, via-hole connections, or the like. In the case of a multilayer printed wiring board in which the required wiring patterns are formed in a substantially intersecting manner on the main surface of the board, for example, the main parts are shown in a cross-sectional view as shown in FIG. 3, and in a planar view as shown in FIG. The configuration is as shown. That is, among the wiring patterns la and lb formed in a substantially intersecting shape on the main surface of the multilayer printed wiring board main body 1, one wiring pattern la is as follows.
A configuration is adopted in which electrical connection is made via a conductor layer 2a formed on the inner wall surface of the through hole 2 provided with the other wiring pattern ib in between and an inner layer wiring pattern le. In other words, by taking advantage of the fact that the wiring density of the inner wiring pattern layer is generally lower than that of the outer wiring pattern layer, through-hole connections are made to substantially intersect on the main surface of the board body 1. It functions as a multilayer printed wiring board with a similar wiring pattern.

(Problem to be Solved by the Invention Ja) However, in the case of the multilayer printed wiring board having the above configuration or structure, the following practical disadvantages are recognized. That is,
Among the wiring patterns la and 1b formed in a substantially intersecting manner on the main surface of the multilayer printed wiring board body 1, one wiring pattern la or wiring pattern tb is formed by adhering to the inner wall surface of the through hole 2, and a conductor layer 2a; Inner layer wiring pattern l
In order to create a configuration in which electrical connections are made through C, it is inevitable that the number of wiring pattern layers will increase, which not only increases the thickness of the multilayer printed wiring board itself and increases the cost, but also makes the wiring pattern itself longer and has different characteristics. There is a problem.

In addition, there are many places where the wiring patterns la and lb are formed in a substantially intersecting manner, and through-hole connections are often used, which limits the area in which the inner layer wiring patterns le can be formed, forcing further multilayering. The manufacturing process is also complicated.

The present invention has been made in response to the above-mentioned circumstances, and is a multilayer printed wiring board having wiring patterns formed substantially intersecting on the main surface of the board, without using through holes or inner layer wiring patterns. The present invention provides a multilayer printed wiring board on which a cross wiring pattern is formed.

[Structure of the Invention] (Means for Solving the Problems) The present invention provides a single printed wiring board on which a required wiring pattern is formed in a substantially intersecting manner at least on the main surface of a main body of a multilayer printed wiring board. The two wires are electrically connected by jumper wiring by wire bonding in the region where one of the wiring patterns that substantially intersect on the main surface of the substrate body intersects with each other.

(Function) According to the present invention, one wiring pattern that substantially intersects on the main surface of the board body is configured to straddle another wiring pattern in the area where it intersects, and to be electrically connected by jumper wiring. Therefore, the wiring pattern can be shortened and lead time can be shortened.

In addition, since the inner layer wiring pattern can be used as another signal wiring pattern, the number of wiring pattern layers can be reduced or multilayer printed wiring pattern can be used! It is possible to make the lji board thinner, and there is no need to provide through-hole connection lands on the main surface of the board.
It is also possible to increase the density of the wiring pattern on the main surface of the substrate.

(Example) Hereinafter, the present invention will be described in detail with reference to FIGS. 1 and 2 showing essential parts of a multilayer printed wiring board according to the present invention. FIG. 1 is a sectional view of the main part, and FIG. 2 is a plan view of the main part. In the figure, 1 is a multilayer printed wiring board body, la and lb are wiring patterns formed to substantially intersect on the main surface of the multilayer printed wiring board body 1, and 3 is one wiring pattern 1.
This is a jumper wiring that straddles the wiring pattern la and electrically connects the wiring pattern la by wire bonding. Thus, the jumper wiring 3 is bonded via the bonding pad 4 provided at the end of the wiring pattern la, which is disposed facing each other with one wiring pattern tb interposed therebetween, thereby establishing an electrical connection between the wiring patterns la. ing. Also, 5 is the jumper arrangement! 1[3 from the outside world and electrically insulatively, ld is an inner wiring pattern layer for signals, and le is a wiring pattern formed on the main surface of the other substrate body 1.

Next, an example of manufacturing the multilayer printed wiring board according to the present invention will be described. First, a surface copper foil-clad laminate having the required inner wiring pattern layer is obtained by conventional means. Next, the copper foil layer of the surface copper foil-clad laminate is selectively etched to form a desired wiring pattern. In other words,
A desired wiring pattern having intersecting regions is formed on the main surface of the laminate by selective etching.

After that, if necessary, a solder resist layer is formed by a printing method on the main surface of the laminate on which the wiring pattern has been formed, and then
It is separated on both sides with one wiring pattern in between.
Bonding butts are provided in regions where the pair of wiring patterns face each other, and jumper wiring is performed between the pair of wiring patterns facing each other by wire bonding. After making the necessary electrical connections, if necessary, the jumper wiring area is covered and protected with, for example, a solder resist, thereby obtaining a desired multilayer printed wiring board.

[Effects of the Invention] As described above, the multilayer printed wiring board according to the present invention, in which the required wiring patterns are formed and provided in a manner that substantially intersects on the main surface of the board, has a structure in which the wiring patterns are connected in the intersecting regions. Since no through holes are used in the structure, the inner wiring pattern layer can be used for other signals. In other words, it is possible to easily increase the density of wiring and reduce the size of multilayer printed wiring boards. In addition, since there is no need to connect wiring patterns on the main surface of the board with inner layer wiring patterns, it is possible to reduce the number of inner layer wiring patterns or use them as other signal wiring patterns, increasing the capacity of multilayer printed wiring boards. obtain. Furthermore, since connections between wiring patterns on the main surface of the board are made by jumper wiring instead of using inner layer wiring patterns and through-holes, there is no need to form connection lands on the main surface of the board, and the wiring pattern can be formed on the main surface of the board. It can be used as an area to increase wiring density.

[Brief explanation of drawings]

FIG. 1 and FIG.
3 and 4 show the main part structure of a conventional multilayer printed wiring board, with FIG. 3 being a sectional view and FIG. 84 being a plan view. 1......Multilayer printed wiring board main body la, l
b...Cross wiring pattern 2 on the main surface of the board...
...Through hole 2a...Through hole conductor layer 3...
...Jumper wiring 4...Bonding butt 5...
・・・Resist layer

Claims (1)

[Claims] A multilayer printed wiring board in which a required wiring pattern is formed so as to substantially intersect at least on the main surface of the board, and wire bonding is performed in an area where one of the wiring patterns that substantially intersects on the main surface of the board intersects. A multilayer printed wiring board characterized by being electrically connected by jumper wiring.