JPH01173776A - Wiring board structure - Google Patents

Abstract

PURPOSE:To microminiaturize an electronic apparatus and to form the apparatus into a extremely small thickness by a method wherein a plurality of wiring boards are adhered and connected to each other through insulating adhesive. CONSTITUTION:Electrical joints 7' of wiring boards 1a and 1b are an insulating adhesive material 2 having a moisture resistance and the boards are adhered and connected to each other through the insulating adhesive materials. By such a constitution, a wiring board structure, wherein the restriction of the height of a hybrid IC and the restriction of its mounting density are significantly improved, can be obtained.

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a wiring board structure formed by laminating a wiring board made by printing and firing a conductive material or a resistive material on an alumina substrate or the like. .

Conventional technology In recent years, the demand for smaller, lighter, thinner, and more sophisticated electronic devices has been increasing, and with this, the issue of how to increase the density and reliability of the circuits in these electronic devices has become an extremely important issue. It is becoming.

Under these circumstances, various mounting technologies have recently been studied in order to increase the density and reliability of electronic circuits.
In particular, a conventional mounting method that has been commonly used is to create a circuit block by integrating the circuit elements that make up the target electronic circuit block, and then mount this circuit block on a mother printed wiring board. There is a method of constructing an electronic circuit.

Devices adopting such a concept of functional blocks have been adopted in many electronic devices because they have excellent effects in reducing the size and density of electronic circuits as well as increasing reliability.

DESCRIPTION OF THE PREFERRED EMBODIMENTS A hybrid IC using an alumina substrate or the like will be described below as an example of a conventional mounting method with reference to the drawings.

In a hybrid IC wiring board using this alumina substrate, wiring conductors including through holes are usually formed by printing and firing a conductive material such as silver palladium. Next, a resistor material is printed and fired to form a resistor, and glass is further printed and fired as a protective film. After adjusting the resistance value of the resistor by laser trimming or the like, electronic components are attached and terminals are connected to complete the product. Figure 4 (a) shows the completed hybrid ICs, with a (a) showing a vertical mounting type and an (a) a vertical mounting type. In the figure, ld and le are wiring boards, 3b and 3c are terminals, and 4 is an electronic component.

Problems to be Solved by the InventionHowever, although the above-mentioned hybrid ICs have been widely adopted in recent years as they meet the concept of functional blocks, there is a strong demand for ultra-miniaturization or ultra-thinness these days. In the field of electronic equipment, miniaturization of modules is still insufficient.

In other words, although the areal density of the motherboard improves in Figure 4A, it is not suitable for devices that are constrained in the height direction, and in Figure 4A, the mounting density is insufficient. It has the disadvantage of being

In view of the above-mentioned problems, the present invention provides an electronic circuit form (wiring board structure) that enables ultra-thinness and ultra-high density.

Means for Solving the Problems In order to solve the above problems, the wiring board structure of the present invention is such that a plurality of wiring boards are tightly connected to each other through an insulating adhesive having moisture resistance. be.

Effects The present invention can provide a wiring board structure that obtains an electronic circuit form that enables ultra-miniaturization and ultra-thinness of electronic equipment by having the above-described configuration.

EXAMPLES Hereinafter, examples of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view of the main parts of an embodiment of the wiring board structure of the present invention, in which 1a and 1b are wiring boards, and 2 is a moisture-resistant insulating adhesive provided between the wiring boards. (adhesive sheet), 7' is a connecting portion for electrically connecting the wiring boards to each other or to other printed wiring boards. FIG. 3 is a pattern diagram of a main part of a wiring board for explaining one embodiment of the present invention. Reference numeral 7 in the figure represents a through hole, which allows the substrate to be divided later along the dividing line shown in FIG. 8 to form an electrical connection portion 7' as shown in FIG. Reference numeral 5 in FIG. 1 shows a resistor formed by printing, and FIG. 6 shows a check land for trimming and checking the resistance of the resistor 5. As shown in Figure 3, after mounting electronic components on a wiring board on which conductor wiring including printed resistors is formed, multiple pieces are glued together with an insulating adhesive interposed as shown in Figure 1.
Then, as shown in FIG. 2, terminals 3a for external connection are attached to complete the wiring board structure. Note that the adhesive sheet 2 interposed between the wiring boards is melted by the flow heat when the terminals 3a are attached, so that the wiring boards can be closely connected to each other.

Here, explanation has been given by taking as an example a sheet-like adhesive material to be interposed, but it goes without saying that a sheet-like adhesive material may also be applied to one side of the wiring board. By interposing these adhesive layers, it is possible to overcome the drawback that the overlapping surfaces of the wiring boards tend to absorb moisture, and improve the moisture resistance, that is, the migration resistance.

Effects of the Invention As is clear from the above explanation, the present invention is extremely useful in that it can provide a wiring board structure that can significantly improve the height restrictions and packaging density restrictions of hybrid ICs, which were conventional drawbacks. You can say that.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a main part showing an embodiment of the wiring board structure of the present invention, FIG. 2 is a sectional view of a main part showing an embodiment of the invention, and FIG. A pattern diagram of a main part of a wiring board for explanation, and FIG. 4A is a sectional view of a main part of a conventional hybrid IC. 1a to 1e...Wiring board, 2...Adhesive sheet, 3a to 3c...Terminal, 4...
・Electronic components, 5...Printed resistors, 6...
Checkland. Name of agent: Patent attorney Toshio Nakao and one other person Figure 1 IcL, Ie----m已! ,! [Figure 4
, 36.3C-satin finish) (teno

Claims (1)

[Claims] A wiring board structure formed by stacking and connecting a plurality of printed wiring boards coated with a conductive material, wherein the overlapping surfaces of the printed wiring boards coated with a conductive material are substantially smooth surfaces, and the overlapping surface has a substantially smooth surface. A wiring board structure characterized in that the entire surface is closely connected via a moisture-resistant insulating adhesive.