JPH0590483A - Substrate for electronic circuit module and electronic circuit module using the same - Google Patents

Abstract

(57) [Summary] [Purpose] The reliability of electrical connection to the mother board is improved, and the pitch of the connection terminals is highly narrowed to achieve miniaturization, and high performance for the mother board. An object of the present invention is to provide an electronic circuit module that enables dense mounting. In an electronic circuit module substrate having a flat plate-shaped main body and a terminal forming portion integrally formed in a peripheral portion of a back surface of the main body in a bulging shape with a constant height, A wiring pattern is formed on each of the flat portions, and terminals that communicate with the wiring patterns are formed on the terminal forming portion.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic circuit module substrate and an electronic circuit module using the same, and in surface mounting on a mother substrate, the electrical reliability in the mounted state is dramatically improved. The present invention relates to a device which can be improved and at the same time achieves a narrower pitch of the terminal portion, which enables higher density mounting of electronic components.

[0002]

2. Description of the Related Art Among conventional electronic circuit modules, hybrid ICs, for example, have recently been increasing in surface mounting type using so-called reflow soldering. It has a structure like. That is, as shown in FIG. 6, a wiring pattern (not shown) is formed on the surface of a material substrate 1 made of glass epoxy or ceramic, and an electronic component 2 such as an IC or a resistor is mounted on this wiring pattern. On the other hand, lead legs 4 made of phosphor bronze or iron are connected to the terminal portions 3 formed at the edge of the material substrate 1 by inserting or soldering. Then, if desired, the whole or a part of the material substrate is covered with a protective film formed by powder coating.

The hybrid IC thus formed is
Surface mounting is performed by a user on a mother board by a so-called solder reflow method using cream solder. In this case, as can be easily understood from FIG. 6, since the lead legs 4 are interposed between the material substrate 1 and the mother substrate, the wiring pattern on the material substrate and the wiring pattern on the mother substrate are separated from each other. There is a problem that the reliability of electrical connection cannot be sufficiently achieved. In particular, the above-mentioned poor electrical connection occurs when the above-mentioned lead legs 4 and the substrate material 1 are not sufficiently connected, or when some of the lead legs 4 are bent and deformed. You can.

Furthermore, the lead legs 4 cannot be made thinner than a predetermined value, and because of the convenience of inserting and connecting the lead legs 4 to the material substrate 1 by an automatic machine, the respective lead legs 4 can be formed. In the case where the distance between them cannot be set to a predetermined value or less and, consequently, a large number of terminals are required, the material substrate itself must be relatively large, which is required on the mother substrate including such hybrid IC. It also becomes a cause of hindering high density mounting of electronic components. Further, as described above, a step for attaching the separately formed lead legs to the material substrate 1 is also necessary, which also causes an increase in cost of the hybrid IC itself.

The present invention was devised under the circumstances described above, and the reliability of electronic connection to a mother substrate can be dramatically improved, and at the same time, the pitch of terminals can be narrowed. It is an object of the present invention to provide a module for an electronic circuit which has been achieved and can achieve reliability when mounted on a mother board and higher density mounting.

[0006]

In order to achieve the above object, the present invention takes the following technical means. That is, the electronic circuit module substrate according to claim 1 of the present application has a flat plate-shaped main body and a terminal formation portion integrally formed in a peripheral portion of the back surface of the main body in a bulged shape with a certain height,
Wiring patterns connected to each other by through holes are formed on the front surface and the back surface of the main body portion, and a plurality of terminals communicating with the wiring pattern are formed on the surface of the terminal formation portion. It is characterized by being.

According to the electronic circuit module of claim 2 of the present application, on the wiring pattern on the front surface and the back surface of the main body portion in the electronic circuit module substrate having the above-mentioned structure,
It is formed by mounting a predetermined electronic component.

[0008]

The substrate for electronic circuit module of the present invention is different from the material substrate used in the conventional hybrid IC and the like, and the terminal forming portion is integrally formed on the back side in a bulge shape with a certain height. Has a three-dimensional structure. That is, this electronic circuit module substrate has a terminal forming portion that bulges at a constant height in the back surface direction at the peripheral portion of the back surface of the flat plate-shaped main body. In this terminal forming portion, a terminal portion connected to a terminal pattern to be formed in the central portion of the back surface of the main body portion is integrally patterned.

Therefore, since the terminal forming portion is formed so as to bulge out at a constant height from the back surface of the main body portion, the terminal portion patterned on this portion is a circuit of the flat mother board. The pattern can be reliably contacted. Since the terminal portion on the module substrate directly contacts the circuit pattern on the mother substrate to establish electrical conduction between them, there is no need to use separately formed lead legs as in the conventional case, and the module is as much as that. The reliability of the electrical connection between the circuit in the board and the circuit on the mother board is achieved.

In addition, in the present invention, the terminal portion can be patterned by a method similar to that of the wiring pattern formed on the substrate, so that the pitch between terminals can be made extremely small. Thus, the electronic circuit module substrate of the present invention or the electronic circuit module using the same, which achieves the narrow pitch, can be remarkably reduced in size as compared with the conventional hybrid IC having the same number of terminals. it can. This means that when the electronic circuit module of the present invention is mounted on the mother board, higher density mounting on the mother board is achieved.

In addition, in the electronic circuit module substrate of the present invention, the bulging terminal forming portion to be integrally formed on the back surface of the flat plate-shaped main portion is formed only in the peripheral portion thereof. , The central flat part of the back surface of this main body is
Since it can still be used as a region for forming a wiring pattern, and therefore electronic components can be mounted on the front surface and the back surface of the main body, high density of electronic components inside the electronic circuit module itself of the present invention can be obtained. It can be installed.

Further, the bulging terminal forming portion to be provided on the back surface of the flat plate-shaped main body is provided around the electronic components mounted on the back surface of the main body when the electronic circuit module board is mounted on the mother board. Since it will function as a protective wall to cover up, even when the IC chip is directly bonded to the wiring pattern on the back surface of the main body, there is no problem even if the means for protecting the directly mounted IC is simple. This also contributes to the cost reduction of electronic circuit module production. Furthermore, conventional hybrid IC
As described above, the step of attaching the separately formed lead legs to the substrate is not necessary, which also greatly contributes to the cost reduction of the electronic circuit module manufacturing.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described.
A specific description will be given with reference to the drawings. 1 is a perspective view schematically showing an embodiment of an electronic circuit module 11 of the present invention, and FIG. 2 is an enlarged sectional view taken along line II-II of FIG.

The substrate 12 used in the construction of the electronic circuit module 11 has a three-dimensional shape formed by, for example, three-dimensional resin injection molding. That is, as shown in FIG. 1 and FIG. 2, the terminal forming portion 14 that bulges at a constant height in the rear surface direction is integrally formed on the peripheral portion on the rear surface side of the flat plate-shaped main body portion 13 having a rectangular shape in plan view. Have been formed in the same way. That is, when viewed from the back surface side, the substrate 12 has a form like a shallow box having an open top. However, the cross-sectional shape of the terminal forming portion 14 has a rounded top for the convenience of forming the terminal pattern by a photosensitizing method, as described in detail later.

The surface side of the main body 13 is flat, and a wiring pattern 16 suitable for mounting the soldering components 15 ... Is formed on the surface side. On the other hand, the wiring pattern 17 is also formed on the central flat surface surrounded by the bulging terminal formation portion 14 on the back surface of the main body portion 13. The wiring pattern 16 on the front surface side and the wiring pattern 17 on the back surface side are electrically connected by a through hole 18 penetrating the main body portion 13. Then, the main body 13 is formed on the surface of the terminal forming portion 14.
Terminal part 1 electrically connected to the back side wiring pattern 17 of
9 is patterned.

Since the cream solder can be printed on the plane surface of the main body 13 because it is flat, the reflow solder can be used for soldering parts 15 ..., such as small chip resistors. Can be installed by the method of. On the other hand, since the back surface of the main body 13 has an uneven surface, it is impossible to mount components by cream solder printing, but the semiconductor chip 20 or the like is directly bonded to the wiring pattern 17, and the semiconductor chip 2 is used.
It is possible to wire bond between 0 and a predetermined lead of the wiring pattern 17.

Various methods are conceivable as a method of patterning the wiring pattern 17 or the terminal portion 19 on the three-dimensional back surface side of the substrate 12. The first is the terminal portion 19 and the back surface side wiring pattern 1
This is a method of resin insert molding the metal punched frame forming 7 However,
This method is disadvantageous in terms of cost because it is necessary to accurately manufacture the metal frame to be finally formed of the above pattern in advance.

The second method is a method utilizing a so-called three-dimensional injection molding method. In this method, as shown in FIG. 3, first, a resin that is adjusted so that a surface after molding is plated is used, and a concavo-convex shape is formed so that only a portion corresponding to a three-dimensional wiring pattern to be formed is exposed at the outermost periphery. A resin prepared by injection molding the above-mentioned base material 21 and then filling the concave portion of the base material obtained by the first molding as described above so that plating does not occur after molding. Insert molding is performed using. As a result, as shown in FIG. 4, a material substrate having an exposed surface in a pattern, which can be plated corresponding to the wiring pattern to be formed, is completed. And then
When this material substrate is subjected to electroless copper plating, the conductor pattern 22 made of copper is formed only on the surface pattern that can be plated.

The third method is a method of forming a pattern by a photographic exposure method. This will be described in detail. First, a base material 21 having an overall shape as shown in FIG. 1 or 2 is injection-molded by using a resin adjusted so that the surface after molding is easily plated. Then, after applying a plating resist to a predetermined part, the plating resist is partially removed in a pattern shape corresponding to the wiring pattern to be formed by a so-called photo-additive method, and in this state, electroless copper plating is applied to the base material. Apply. And finally, the plating resist remaining on the surface is removed by chemicals.

By the way, an electronic circuit module substrate of this type which is to be surface-mounted on a mother substrate has a temperature of 200.degree.
Heat resistance that can sufficiently withstand repeated temperature rise is required, but as a resin material that satisfies such requirements, polyether sulfone (PES), polyphenylene sulfide (PPS), liquid crystal polymer (LCD), etc. are suitable. is there. Such a material is not only excellent in heat resistance but also excellent in workability by injection molding as described above.

The electronic circuit module 11 having the above configuration
On the front surface of the terminal forming portion 14 that bulges at a constant height on the back surface of the substrate main body 13, a plurality of terminal portions 19 that are electrically connected to the wiring patterns 16 and 17 formed on the front and back surfaces of the main body portion 13 are provided. Since the integrated pattern is formed, the terminal portion 19 is directly connected to the mother board. Since the terminal forming portion 14 is formed so as to bulge to a constant height, all of the terminal portions 19 formed on this surface can surely come into contact with the flat mother board. Will be able to, therefore, the substrate 1
The reliability of the electrical connection between the second wiring and the wiring of the mother substrate is significantly improved as compared with the conventional one. In addition, the terminal portion 1
Since 9 is formed by pattern formation, it is possible to make the pitch interval of the plurality of terminal portions 19 extremely small. Therefore, miniaturization of the electronic circuit module 11 itself can be achieved, and high-density mounting on the mother board can be achieved.

In addition, unlike the conventional hybrid IC, since it is not necessary to separately form the lead legs for connecting to the mother substrate and to connect the lead legs to the substrate, an effect of cost reduction due to the reduction of man-hours can be expected. be able to.

Further, as can be seen from FIG. 2, the main body 1
The space on the back surface of 3 is surrounded by the bulging terminal forming portion 14 formed so as to surround the peripheral portion of the main body portion on the back surface side in a state where the module 11 is mounted on the mother board. Therefore, the main body 13
Even when the semiconductor chip 20 is directly bonded to the back surface side of and the wiring pattern 17 and the semiconductor chip 20 are connected by wire bonding, the resin sealing means 23 for protecting the semiconductor chip 20 or the wire bonding portion is simplified. This also contributes to cost reduction for forming an electronic circuit module.

As shown in FIG. 5, the above electronic circuit module substrate is assembled into a plurality of columns and a plurality of rows at the same time, and at the same time, a plurality of electronic components are attached at the same time. If the manufacturing method of dividing along the dividing V groove 24 to obtain each unit substrate is adopted, the manufacturing efficiency is very good.

Of course, the present invention is not limited to the above embodiment. In particular, in the substrate, the terminal formation portion which is to be bulged and formed on the back surface thereof does not necessarily have to be provided over the entire circumference of the back surface of the main body portion, and may be partially formed. However, it goes without saying that this bulged terminal forming portion is also a portion that directly contacts the mother substrate to ensure stable support of the entire circuit module, and therefore should be formed in consideration of this fact.

[Brief description of drawings]

FIG. 1 is an overall perspective view schematically showing an embodiment of an electronic circuit module of the present invention.

FIG. 2 is an enlarged sectional view taken along line II-II of FIG.

[Figure 3]

FIG. 4 is an explanatory diagram of an example of a method of forming a terminal pattern on a terminal forming portion.

FIG. 5 is an explanatory view of an example of a method of manufacturing an electronic circuit module substrate of the present invention.

FIG. 6 is an explanatory diagram of a conventional example.

[Explanation of symbols]

 11 Electronic Circuit Module 12 Substrate for Electronic Circuit Module 13 Main Part 14 Terminal Forming Part 15 Electronic Component 16, 17 Wiring Pattern 18 Through Hole 19 Terminal Part

Claims (2)

[Claims] 1. A flat plate-shaped main body, and a terminal forming portion integrally formed on the peripheral portion of the back surface of the main body in a bulging shape with a constant height. The electronic circuit module is characterized in that a wiring pattern interconnected with each other through a through hole is formed, and a plurality of terminals communicating with the wiring pattern are formed on the surface of the terminal formation portion. Substrate. 2. The electronic circuit module according to claim 1, wherein electronic components are mounted on the wiring patterns formed on the front surface and the back surface of the main body in a predetermined manner.