JPH0548262A - Composite hybrid integrated circuit - Google Patents

Abstract

PURPOSE:To protect a soldered part of an electronic component mounted on a metal insulating board by suppressing heat transfer to the board when a composite hybrid integrated circuit in which an IC module having the board and a mother printed circuit board of a copper-plated laminated board are assembled and soldered therebetween by a dip soldering method, is dip soldered. CONSTITUTION:Tongue-like insertion legs 4b aligned to locally protrude from an edge of a metal insulating board 4 are provided at the end of the board 4, and terminal lands 4a to be externally connected to the legs are distributed to be formed. The legs are inserted into an insertion hole 1a of a mother printed circuit board 1, and soldered to be connected therebetween by a dip soldering method.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite type hybrid integrated circuit constructed by incorporating an IC module using a metal insulating substrate into another mother board printed wiring board, and more particularly between a metal insulating substrate and a mother board printed wiring board. The structure of the soldering part.

[0002]

2. Description of the Related Art As the above-mentioned hybrid hybrid integrated circuit, a structure as shown in FIG. 9 has been conventionally practiced.
In the figure, 1 is a mother board printed wiring board that employs a copper clad laminated board based on a paper epoxy resin laminated board, 2 is an electronic component mounted on the printed wiring board 1, and 3 is a metal insulating board 4 having high heat conductivity. A power IC module in which an electronic component 5 such as a power chip is mounted on (an insulating film is laminated on a metal base having high heat conductivity such as aluminum, and a conductor pattern of a copper foil is formed thereon). The IC module 3 is incorporated in the motherboard printed wiring board 1 as follows. That is, an insertion hole 1a corresponding to the cross-sectional dimension of the metal insulating substrate 4 is opened in a part of the board surface of the motherboard printed wiring board 1, and the tip of the metal insulating substrate 4 of the IC module 3 is inserted into this insertion hole. The motherboard printed wiring board 1 is inserted and connected so as to project to the back surface side, and then the terminal lands 1b and 4a of the conductor pattern formed on each board are soldered. In addition,
The solder joint is shown at 6. Further, when soldering between the mother board printed wiring board 1 and the metal insulating board 4, the board is dipped in a solder bath in a solder bath with the back surface of the mother board printed wiring board 1 facing downward for soldering. The dip soldering method is generally adopted.

[0003]

By the way, when the metal insulating substrate 4 having a high heat conductivity and the mother board printed wiring board 1 are combined and dip-soldered between them as described above, the heat of the molten solder contained in the solder bath is reduced. Heats the soldered portion of the electronic component 5 mounted on the IC module 3 while passing through the metal insulating substrate 4 having high heat conductivity. Moreover, in the structure in which the front end of the metal insulating substrate 4 penetrates the insertion hole 1a over the entire width and projects to the back surface side of the motherboard printed wiring board 1 as shown in FIG. 9, the liquid contact area with the molten solder is large. Therefore, the amount of heat transferred to the metal insulating substrate 4 also increases. On the other hand, eutectic solder (melting point 183 ° C.) is generally used for soldering between the metal insulating substrate 3 and the electronic component 5. On the other hand, the molten solder contained in the solder bath for dip soldering is heated to a high temperature of about 250 ° C. Therefore, the soldering portion of the electronic component 5 mounted on the metal insulating substrate 4 is remelted by the heat transmitted through the metal insulating substrate 4 and the mounting position of the electronic component is displaced, or the soldering strength is reduced. In the worst case, the electronic component 5 often comes off from the substrate.

Therefore, conventionally, the metal insulating substrate 4 of the IC module 3 and the electronic component 5 are assembled by soldering with a high melting point solder, and the space between the metal insulating substrate 4 and the mother board printed wiring board 1 is assembled. A method of preventing solder remelting of mounted components by using a low melting point solder has been proposed. However, in such a method, there is a case where the high melting point solder cannot be used due to the restriction of the heat resistant temperature of the electronic component 5, and an alternative measure is desired.

The present invention has been made in view of the above points, and an object thereof is to improve the shape of an end portion of a metal insulating substrate to be inserted into an insertion hole of a mother board printed wiring board so that it is melted during dip soldering. (EN) Provided is a composite hybrid integrated circuit, in which the amount of heat transferred from the solder to the metal insulating substrate can be minimized to safely protect the soldered part of the mounted electronic component, especially the structure of the soldered part. ..

[0006]

SUMMARY OF THE INVENTION According to the present invention, the above object is to provide a tongue-shaped insertion leg portion at the end of a metal insulating substrate, which locally projects from the edge of the substrate and is arranged in the leg portion. This is achieved by allocating and forming terminal lands for external connection, and inserting the insertion legs into the insertion holes of the motherboard printed wiring board for soldering.

Further, in the above-mentioned structure, heat having low thermal conductivity is included in at least the surface area of the metal base of the metal insulating substrate, including the insertion leg, which is immersed in the solder bath during dip soldering. It is preferable to deposit an insulating film. For this heat insulating film, a heat insulating material such as a solder resist or a silk resist, or a heat-resistant adhesive tape that can be removed after soldering can be used.

Further, instead of partially depositing the heat insulating film on the metal insulating substrate as described above, is a metal insulating substrate formed by forming an insulating layer on both surfaces of the metal base? Alternatively, it is also possible to employ a metal insulating substrate which is a double-sided printed wiring board in which an insulating layer and a conductor pattern are formed on both sides of a metal base.

[0009]

According to the above construction, when the IC module and the mother board printed wiring board are dip-soldered, only the tongue-shaped insertion leg portion protruding from the edge of the metal insulating substrate is soldered. It is only immersed in the high-temperature molten solder contained in the bath, and since this insertion leg is narrower than the entire width of the metal insulating substrate, the amount of heat transferred from the solder bath to the metal insulating substrate is the area of this leg. Will be limited by. In this case, the mother board printed wiring board is a copper clad laminated board having a low heat conductivity, and the influence of heat transferred to the metal insulating board via the copper clad laminated board is negligible.
This can prevent the soldering part of the electronic component mounted on the metal insulating substrate from being heated to a high temperature and remelting the solder.

In addition, a heat insulating film is deposited on the metal base of the metal insulating substrate, including the above-mentioned insertion leg, at least in the surface area of the portion to be immersed in the molten solder during dip soldering. As a result, since this heat insulating film acts as a heat transfer resistance, the amount of heat transferred to the metal insulating substrate, that is, the temperature rise of the soldered portion of the mounted electronic component can be further suppressed.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. Embodiment 1 FIG. 1 shows a basic embodiment corresponding to claim 1 of the present invention, in which an end portion of a metal insulating substrate 4 of an IC module 3 inserted into an insertion hole 1a of a motherboard printed wiring board 1 is shown. Is a plurality of categories (3 categories in the example shown)
A tongue-shaped insertion leg portion 4b is locally formed so as to protrude locally from the edge of the board, and is distributed to each leg portion 4b and the terminal land for external connection is drawn out from the conductor pattern on the surface. 4a is formed. Then, in order to assemble the IC module 3 into the motherboard printed wiring board 1, the insertion leg portion 4b protrudingly formed at the end portion of the metal insulating substrate 4 is used.
Is inserted into the insertion hole 1a of the mother board printed wiring board 1 to connect them, and in this temporary assembled state, the mother board printed wiring board 1 is formed by the dip soldering method as in the conventional method.
The terminal lands are soldered to each other between and the metal insulating substrate 4.

With the above construction, when the assembly of the mother board printed wiring board 1 and the IC module 3 is immersed in the molten solder 8 contained in the solder bath 7 as shown in FIG. Regarding the metal insulating board 4, the insertion leg portion 4 of the metal insulating board 4 which penetrates the insertion hole 1a of the motherboard printed wiring board 1 and projects to the back surface side.
Only b comes into contact with the molten solder 8. Moreover,
The individual insertion leg portions 4b are narrower than the entire width of the metal insulating substrate 4, and therefore the heat from the solder bath is limited by the heat transfer area of the narrow leg portions 4b as indicated by the dotted arrow, and a small amount of heat is generated. Only heat is transferred to the metal insulating substrate 4. On the other hand, the entire area of the mother board printed wiring board 1 is immersed in the molten solder 8. However, since the mother board printed wiring board 1 employs a copper clad laminated board having a low heat conductivity, it is possible to interpose the metal through the board. The heat transferred to the insulating substrate 4 is extremely small and has almost no effect on the electronic components of the metal insulating substrate 4.

Embodiment 2 FIG. 2 is an application embodiment of Embodiment 1 shown in FIG. 1, in which the insertion hole 1a formed in the mother board printed wiring board 1 is formed at the end of the metal insulating substrate 4 so as to project therefrom. Dispersion openings are provided corresponding to the respective embedded legs 4a. With this configuration, the motherboard printed wiring board 1
Since the temporary assembly posture in which the IC module 3 is inserted and connected to the insertion hole 1a is more stable as compared with the first embodiment, and an unnecessary blank portion does not occur in the insertion hole 1a, the dip soldering shown in FIG. At this time, even if the molten solder 8 is slightly wavy, it is possible to prevent the high temperature molten solder 8 from coming into contact with the main body of the metal insulating substrate 4 through the insertion hole.

Embodiment 3 FIG. 3 shows a further different embodiment of the present invention. In particular, the depth of the groove between the inserting leg portions 4b protruding in a line from the edge of the metal insulating substrate 4 is different. ,
The metal insulating substrate 4 is formed so as to be deeper than the end faces at the left and right ends by a dimension d. By increasing the depth of the groove between the insertion legs 4b as described above, even if the liquid surface of the molten solder 8 is slightly wavy during the dip soldering shown in FIG. It is possible to prevent an increase in the liquid contact area between the substrate 4 and the molten solder, and to minimize the amount of heat transfer from the solder bath to the metal insulating substrate 4.

Embodiment 4 FIG. 5 shows an embodiment corresponding to claims 2 to 4 of the present invention, which is a further improvement of the above-mentioned embodiments. In this embodiment, with respect to the metal base of the metal insulating substrate 4, at least the surface area of the portion to be immersed in the molten solder at the time of dip soldering (the portion shown by hatching), that is, the insertion leg portion 4b is included. A thermal insulation film 9 having a low thermal conductivity is applied to the edge region of the substrate. By applying such a heat insulating film 9, the heat insulating film 9 acts as a heat transfer resistance during dip soldering, so that heat transfer from the high temperature molten solder to the metal insulating substrate 4 can be effectively suppressed. You can The heat insulating film 9 may be applied using a solder resist, a silk resist, or the like, or a heat resistant insulating adhesive tape may be attached so that it can be removed after soldering.

Embodiment 5: FIG. 6 shows an embodiment corresponding to claim 5 of the present invention. That is, in this embodiment, an insulating layer 11 made of the same material is previously formed on both surfaces of the metal base 10 without depositing a heat insulating film on the metal insulating substrate 4 as in the embodiment described with reference to FIG. The manufactured metal insulating substrate 4 is adopted, and the tongue-shaped insertion leg portion 4b similar to that of the first embodiment is formed at the end portion of the metal insulating substrate 4. With this configuration, the same effect as that of the above-described fourth embodiment can be obtained.

FIG. 7 shows a solder joint between a mother board printed wiring board 1 as a single-sided printed wiring board and an IC module 3 in which an electronic component 5 is mounted on a metal insulating substrate 4 also as a single-sided printed wiring board. 1 shows an assembled structure of a composite hybrid integrated circuit configured. In the figure, 13 is a soldering portion by the above-mentioned dip soldering, 14 is a solder resist, and 15 is a soldering portion in which the electronic component 5 and the conductor pattern 16 of the metal insulating substrate 4 in the IC module 3 are joined. , 17 are copper foils of the motherboard printed wiring board 1.

Further, FIG. 8 employs a metal insulating substrate 4 which is a double-sided printed wiring board in which an insulating layer 11 and a conductor pattern 16 are formed on both sides of a metal base 10 as a circuit board of the IC module 3, and the IC module 3 is used. 1 shows an assembled structure of a composite type hybrid integrated circuit which is combined with a mother board printed wiring board 1 and solder-bonded between them.

[0019]

Since the hybrid hybrid integrated circuit of the present invention is constructed as described above, it has the following effects. (1) A tongue-shaped insertion leg portion is provided at an end portion of the metal insulating substrate so as to locally project from an edge of the substrate, and a terminal land for external connection is distributed to the insertion leg portion and formed.
Minimize the heat transfer from the high temperature solder bath to the metal insulating substrate even when the dip soldering method is adopted by inserting the insertion leg into the insertion hole of the motherboard printed wiring board and soldering it As a result, it is possible to prevent re-melting of the electronic components mounted on the metal insulating substrate and the accompanying reduction in soldering strength, thereby significantly improving the reliability of the product.

(2) Further, in the above construction, a heat insulating film having a low heat conductivity is applied to at least a surface area of a portion of the metal base of the metal insulating substrate which is immersed in a solder bath during dip soldering. This makes it possible to more effectively suppress heat transfer from the solder bath to the metal insulating substrate during dip soldering.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of a composite type hybrid integrated circuit according to a first embodiment of the present invention.

FIG. 2 is an exploded perspective view of a composite type hybrid integrated circuit according to a second embodiment of the present invention.

FIG. 3 is an outline view of a metal insulating substrate according to a third embodiment of the present invention.

[Fig. 4] Soldering state diagram between the motherboard printed wiring board and the metal insulating substrate

5A and 5B are structural views of a metal insulating substrate according to Example 4 of the present invention, in which FIG. 5A is a plan view and FIG. 5B is a side view.

FIG. 6 is an external perspective view of a metal insulating substrate according to a fifth embodiment of the present invention.

FIG. 7 is a sectional view showing the structure of a composite type hybrid integrated circuit assembled by using a metal insulating substrate of a single-sided printed wiring board.

FIG. 8 is a sectional view showing the structure of a composite type hybrid integrated circuit assembled using a metal insulating substrate of a double-sided printed wiring board.

FIG. 9 is a perspective view of a conventional hybrid hybrid integrated circuit.

[Explanation of symbols]

 1 Mother Board Printed Wiring Board 1a Insertion Hole 3 IC Module 4 Metal Insulation Board 4a Terminal Land 4b Insertion Leg 5 Electronic Component 8 Molten Solder

Claims (6)

[Claims] 1. A composite hybrid integrated circuit in which a module in which electronic components are mounted on a metal insulating substrate is incorporated into a mother board printed wiring board of a copper clad laminated substrate, and terminal lands for external connection are arranged in a horizontal row. Insert the ends of the lined metal insulating boards into the insertion holes provided on the motherboard printed wiring board to connect them, and connect the terminals between the ends of the metal insulating boards protruding to the back side of the motherboard printed wiring board and the motherboard printed wiring board. In the case where the lands are soldered to each other, a tongue-shaped insertion leg portion is provided at the end portion of the metal insulating substrate so as to locally project from the substrate edge, and the external connection terminal land is provided on the insertion leg portion. A composite hybrid integrated circuit, which is formed separately, and in which the insertion leg portion is inserted into an insertion hole of a motherboard printed wiring board and soldered. 2. The composite hybrid integrated circuit according to claim 1, wherein at least a surface area of a portion of the metal base of the metal insulating substrate, including the insertion leg portion, is immersed in a solder bath at the time of dip soldering. A hybrid hybrid integrated circuit characterized by being coated with a heat insulating film having low thermal conductivity. 3. The composite hybrid integrated circuit according to claim 2, wherein the heat insulating film is a solder resist or a silk resist. 4. The composite hybrid integrated circuit according to claim 2, wherein the heat transfer resistance film is a heat-resistant adhesive tape which can be removed after soldering. 5. The composite hybrid integrated circuit according to claim 1, wherein an insulating layer is formed on both surfaces of the metal base of the metal insulating substrate. 6. The composite hybrid integrated circuit according to claim 1, wherein the metal insulating substrate is a double-sided printed wiring board on which insulating layers and conductor patterns are formed on both surfaces.