JP3174957B2 - Electronic circuit module substrate and electronic circuit module using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a substrate for an electronic circuit module and an electronic circuit module using the same. The present invention relates to a device that can be improved and achieves a narrower pitch of a terminal portion, thereby enabling higher-density mounting of electronic components.

[0002]

2. Description of the Related Art Among conventional electronic circuit modules, for example, hybrid ICs, for example, surface-mount type ICs using so-called reflow soldering have been increasing recently. The configuration is as follows. 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 the wiring pattern. On the other hand, a lead leg 4 made of phosphor bronze or iron is connected to the terminal portion 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.

[0003] The hybrid IC thus formed is
A user performs surface mounting 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, the lead foot 4 is interposed between the material substrate 1 and the mother substrate, so that the wiring pattern on the material substrate and the wiring pattern on the mother substrate are interposed. There is a problem that the reliability of the electrical connection cannot be sufficiently achieved. In particular, when the connection between the lead foot 4 and the substrate material 1 is not sufficiently established, or when some of the lead feet 4 are bent and deformed, the above-described electrical connection failure occurs. Can.

Further, the lead legs 4 cannot be made thinner than a predetermined thickness, and the lead legs 4 are inserted into and connected to the material substrate 1 by an automatic machine. In the case where the distance between the substrates cannot be reduced to a predetermined value or less and a large number of terminals are required, the material substrate itself has to be relatively large, and the material substrate itself has to be formed on a mother substrate including such a hybrid IC. In addition, this may hinder the increase in the density of electronic component mounting. Further, as described above, a step for attaching the separately formed lead foot to the material substrate 1 is also required, which also causes an increase in the cost of the hybrid IC itself.

The present invention has been made in view of the above circumstances, and it is possible to dramatically improve the reliability of electronic connection to a mother board, and to simultaneously reduce the pitch of terminals. It is an object of the present invention to provide an electronic circuit module which can achieve high reliability when mounted on a motherboard and higher density mounting.

[0006]

In order to achieve the above object, the present invention employs the following technical means. In other words, the electronic circuit module substrate according to claim 1 of the present application is formed integrally with a flat plate-shaped main portion having a flat surface up to the outer edge, and with a constant height bulging shape on the peripheral portion of the back surface of the main portion. And, while having a terminal forming portion reaching the top while the inner surface and the outer surface are rounded , these plate-shaped main portion and the terminal forming portion are integrally formed of resin,
Wiring patterns connected to each other by through holes are formed on the front surface of the main body portion and the flat portion on the back surface, and the surface of the terminal forming portion is connected to the wiring pattern and connected to the terminal forming portion. A plurality of terminals that can reach the mother substrate up to the top are patterned.

The electronic circuit module according to a second aspect of the present invention provides a circuit board for an electronic circuit module having the above-described structure, in which the wiring pattern on the front surface and the back surface of the main part is
It is formed by mounting predetermined electronic components.

[0008]

The electronic circuit module substrate of the present invention differs from the material substrate used for the conventional hybrid IC and the like in that the terminal forming portion is integrally formed on the rear surface side in a swelling manner at a constant height. Has a three-dimensional structure. That is, the electronic circuit module substrate has a terminal forming portion that swells at a constant height in the back surface direction on the periphery of the back surface of the flat main body. In the terminal forming portion, a terminal portion connected to a terminal pattern to be formed in the center of the back surface of the main portion is integrally formed in a pattern.

Therefore, since the terminal forming portion is formed so as to protrude from the back surface of the main portion at a constant height, the terminal portion patterned on this portion is formed on a circuit board of a flat mother board. The pattern can be reliably contacted. Since the terminal portions on the module substrate directly contact the circuit patterns on the mother substrate to achieve electrical continuity therebetween, there is no need to use separately formed lead legs as in the related art, and the module Reliability of the electrical connection between the circuit on the board and the circuit on the mother board is achieved.

In addition, in the present invention, the terminal portion can be formed by the same method as the wiring pattern formed on the substrate, so that the pitch between the terminals can be made extremely small. Thus, the electronic circuit module substrate of the present invention or the electronic circuit module using the same, in which the pitch can be narrowed, can be significantly 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 a motherboard, higher-density mounting on the motherboard is achieved.

In addition, in the electronic circuit module substrate of the present invention, the bulge-shaped terminal forming portion to be integrally formed on the back surface of the flat main portion is formed only at the peripheral portion thereof. , A flat central part on the back side of this main part,
Since it can still be used as a region where a wiring pattern is to be formed, and thus it is possible to mount electronic components on the front and back surfaces of the main part, the high density of electronic components inside the electronic circuit module itself of the present invention is achieved. It can be installed.

Further, when the electronic circuit module substrate is mounted on the motherboard, the bulge-shaped terminal forming portion to be provided on the back surface of the flat main body portion surrounds the electronic component mounted on the back surface of the main body portion. Since it functions as a protective wall for covering and hiding, even when the IC chip is directly bonded to the wiring pattern on the back surface of the main body, the protection means of the directly mounted IC may be simplified. This also contributes to a reduction in the cost of manufacturing an electronic circuit module. Furthermore, conventional hybrid ICs
As described above, since the step of attaching the separately formed lead foot to the substrate is not required, this also greatly contributes to a reduction in the cost of manufacturing the electronic circuit module.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below.
This will be specifically described with reference to the drawings. FIG. 1 is a perspective view schematically showing an embodiment of the electronic circuit module 11 of the present invention, and FIG. 2 is an enlarged sectional view taken along line II-II in FIG.

The substrate 12 used for the configuration of the electronic circuit module 11 has, for example, a three-dimensional form formed by three-dimensional resin injection molding. That is, as shown in FIGS. 1 and 2, the terminal forming portion 14 swelling at a constant height in the back surface direction is integrally formed on the peripheral portion on the back surface side of the flat main body 13 having a rectangular shape in a plan view. Is formed. That is, the substrate 12 is flat until the surface of the main portion reaches the outer edge, and the terminal forming portion 14 is formed on the peripheral portion on the rear surface side. It is shaped like a shallow box. However, the cross-sectional shape of the terminal forming portion 14 is, as described in detail later,
For the convenience of forming a terminal pattern by a photographic method, the top is rounded.

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

Since the planar surface of the main body 13 is flat up to the outer edge of the substrate, the planar area of the substrate is fully utilized, and a small chip resistor or the like is used. The soldering parts 15 can be mounted by a reflow soldering method. On the other hand, since the rear surface of the main body 13 has an uneven surface, it is impossible to mount components by cream solder printing. However, the semiconductor chip 20 and the like are directly bonded to the wiring pattern 17 and It is possible to perform wire bonding between predetermined leads of the wiring pattern 17.

By the way, as a method of forming the wiring pattern 17 or the terminal portion 19 on the three-dimensional back side of the substrate 12, various methods can be considered. The first is that the terminal portion 19 and the back side wiring pattern 1
This is a method of performing resin insert molding on a metal stamped and formed frame that constitutes No. 7. However,
This method is disadvantageous in terms of cost, for example, it is necessary to accurately prepare a metal frame to be finally formed with the above pattern.

The second method is a method utilizing a so-called three-dimensional injection molding method. In this method, first, as shown in FIG. 3, a resin adjusted so that plating is applied to the surface after molding is used, and the uneven surface is formed so that only a portion corresponding to a three-dimensional wiring pattern to be formed is exposed to the outermost periphery. Injection molding of the base material 21, and then, as described above, a resin adjusted so as to fill the recesses of the base material obtained by the first molding so that plating does not occur after the formation. Is used to perform insert molding. Then, as shown in FIG. 4, a material substrate having a pattern-like exposed surface, which can be plated in correspondence with 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 method. More specifically, first, a base material 21 having an overall shape as shown in FIG. 1 or FIG. 2 is injection-molded using a resin adjusted so that plating is easily applied to the surface after molding. Then, after applying a plating resist to a predetermined portion, the plating resist is partially removed in a pattern shape corresponding to a wiring pattern to be formed by a so-called photo-additive method, and in this state, the base material is subjected to electroless copper plating. Is applied. Finally, the plating resist remaining on the surface is removed by a chemical.

An electronic circuit module substrate of this type to be surface-mounted on a mother substrate has a temperature of 200 ° C.
Although heat resistance that can sufficiently withstand repeated temperature rise is required, resin materials satisfying such requirements include polyethersulfone (PES), polyphenylene sulfide (PPS), and liquid crystal polymer (LCD). is there. Such a material is not only excellent in heat resistance but also excellent in workability by the injection molding as described above.

Electronic circuit module 11 having the above configuration
A plurality of terminal portions 19 electrically connected to the wiring patterns 16 and 17 formed on the front surface and the back surface of the main portion 13 are provided on the surface of the terminal forming portion 14 bulging at a certain height on the back surface of the substrate main portion 13. Since the terminal pattern 19 is formed as an integral pattern, the terminal 19 is directly connected to the motherboard. Since the terminal forming portion 14 is formed to bulge at a certain height, all of the terminal portions 19 formed on this surface can surely come into contact with the flat motherboard. And thus the substrate 1
The reliability of the electrical connection between the wiring of No. 2 and the wiring of the mother board is remarkably improved as compared with the related art. The terminal 1
Since 9 is formed by pattern formation, the pitch interval between the plurality of terminal portions 19 can be made extremely small. Therefore, downsizing of the electronic circuit module 11 itself can be achieved, and high-density mounting on the motherboard is achieved.

In addition, unlike the conventional hybrid IC, it is not necessary to separately form a lead leg for connecting to the mother substrate and connect it to the substrate, so that an effect of cost reduction by reducing the number of steps can be expected. be able to.

Further, as can be seen from FIG.
The space on the back surface of 3 is surrounded by a bulged terminal forming portion 14 formed so as to surround the peripheral portion of the main body portion on the back surface side when the module 11 is mounted on the motherboard. Therefore, if the main body 13
In the case where the semiconductor chip 20 is directly bonded to the back surface of the semiconductor chip 20 and the wiring between the semiconductor chip 20 and the wiring pattern 17 is 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 the electronic circuit module.

As shown in FIG. 5, the electronic circuit module substrate is assembled in a plurality of rows and a plurality of rows to form a plurality of the boards at the same time. If a manufacturing method of obtaining each unit substrate by dividing along the dividing V-groove 24 is adopted, the manufacturing efficiency is very good.

Of course, the present invention is not limited to the embodiment described above. In particular, in the substrate, the terminal forming portion to be formed on the back surface of the substrate does not necessarily need to be provided over the entire back surface of the main portion, and may be formed partially. However, since the swelling terminal forming portion is also a portion for directly contacting the mother board to stably support the entire circuit module, it is needless to say that the swelling terminal forming portion should be formed in consideration of this fact.

[Brief description of the drawings]

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

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

FIG. 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 diagram of an example of a method for manufacturing an electronic circuit module substrate according to the present invention.

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

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Electronic circuit module 12 Substrate for electronic circuit modules 13 Main part 14 Terminal formation part 15 Electronic component 16, 17 Wiring pattern 18 Through hole 19 Terminal part

Continuation of the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01L 25/00-25/18 H01L 23/12

Claims (2)

(57) [Claims] 1. A plate-shaped main body portion having a flat surface up to the outer edge and are integrally formed at a constant height bulging shape to the peripheral portion of the back surface of the main body portion, and top with a round inner surface and an outer surface The flat main portion and the terminal forming portion are integrally formed of resin, and the front surface of the main portion and the flat portion on the back surface are connected to each other by through holes. A wiring pattern is formed, and a plurality of terminals that are in contact with the wiring pattern and reach the top of the terminal forming portion and are capable of contacting the mother board are formed on the surface of the terminal forming portion. Characteristic substrate for electronic circuit modules. 2. An electronic circuit module according to claim 1, wherein a predetermined electronic component is mounted on a wiring pattern formed on a front surface and a back surface of said main part.