JPH04266054A - Preparation of a mounting board for electronic components - Google Patents

Abstract

PURPOSE:To provide a preparation method which is capable of easily producing a high quality mounting board for electronic components by confining in a defined area the outflow of a brazing medium from each juncture between an inner lead element and an outer lead element. CONSTITUTION:An outflow prevention dam 30 is formed at a predetermined position on each outer lead element 20b to prevent the outflow of a brazing medium 40. Each of leads 20 is constituted by jointing the defined outer end of an inner lead element 20a and the inner end of each outer lead element 20b together.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a board for mounting electronic components, in which each lead is formed by an inner lead member and an outer lead member which are formed separately.

0002

2. Description of the Related Art Various types of electronic component mounting boards for electrically connecting electronic components such as semiconductor chips with the outside have been devised to date. Among them, there is a type in which a large number of leads protrude from an insulating base material on which the electronic component is mounted to electrically connect the electronic component to the outside, and a special type is as shown in Figure 4. In some cases, the lead 20 shown in FIG. 1 is constructed by an inner lead member 20a and an outer lead member 20b which are formed separately.

[0003] Such electronic component mounting substrates are manufactured by mounting electronic components on an insulating base material and then sealing the entire electronic component with so-called molding resin with the outer lead member protruding. This is an on-board device.

By the way, in the electronic component mounting board as described above, each lead is composed of an inner lead member and an outer lead member which are formed separately.
In the manufacturing process, it is necessary to electrically and physically integrate both lead members.

Therefore, conventionally, in the manufacturing process of this type of electronic component mounting board, in order to form each lead, each predetermined outer end of an inner lead member and each predetermined inner end of an outer lead member are connected. The manufacturing process includes electrically and physically integrating both lead members by joining the ends with an electrically conductive brazing material such as solder.

[0006]

[Problems to be Solved by the Invention] However, when the leads 20 are integrated through the manufacturing process as described above, as shown in FIG. The solder material 40 may flow out, and the thickness of the lead 20 may become uneven due to the flowed brazing material 40. If this happens, as shown in FIG. 5, when these are sealed with mold resin, the uneven thickness of the leads 20 will interfere with the mold, resulting in a gap between the upper and lower molds. This may cause the resin to flow out from the gap when the mold resin is injected into the mold.

Therefore, when forming the leads 20 by joining the inner lead member 20a and the outer lead member 20b, which are formed separately, according to the conventional manufacturing process as described above, the upper and lower molds are In order to prevent gaps between the leads 20 and 20,
This method requires complicated work such as making the thickness uniform, and has the drawback that it is difficult to easily obtain a high-quality substrate for mounting electronic components.

[0008] The present invention was devised in view of the above, and its purpose is to reduce the amount of brazing filler metal flowing out from each joint between the inner lead member and the outer lead member. It is an object of the present invention to provide a manufacturing method that can easily obtain a high quality electronic component mounting board.

[0009]

[Means for Solving the Problems] In order to solve the above-mentioned problems, the means taken by the present invention are described with reference numerals used in the embodiments shown below. Lead member 20a and outer lead member 20
b are integrally joined with a brazing material 40 such as solder to form a large number of leads 20, and the insulating base material 10 is integrated with each lead 20 protruding outward from both sides of these leads 20. 1. A method of manufacturing a board 100 for mounting an electronic component, which is formed using a method of manufacturing a board 100 for mounting an electronic component, characterized in that the manufacturing method includes the following steps. (B) Forming outflow prevention dams 30 for preventing outflow of the brazing material 40 at each predetermined position of the outer lead member 20b; (B) At each predetermined outer end of the inner lead member 20a and the outer lead member 20b. and each predetermined inner end of the lead 20 is bonded to each predetermined inner end with the brazing material 40 to form each lead 20.
It is.

That is, the feature of the manufacturing method according to the present invention is that the inner lead member 20a and the outer lead member 20
Before the step of joining b with the brazing material 40, the brazing material 4
The present invention includes a step of forming an outflow prevention dam 30 on the outer lead member 20b to limit the outflow range of zero.

The outflow prevention dam 30 may be formed by forming the outflow prevention dam 30 into a frame shape by punching or the like on the outer lead member 20b using an adhesive, or by a printing method or a stamping method. Any method may be used. The material is not particularly limited as long as it can withstand the heat generated when the brazing filler metal 40 is melted. From the viewpoint of easy removal, polyimide that can be peeled off and polycarbonate that can be dissolved in an organic solvent are suitable. Furthermore, the shape of the outflow prevention dam 30 is not particularly limited, and may be frame-shaped as shown in the embodiment or formed only on the upper surface of the outer lead member 20b. Any shape, as long as it has a dam effect to prevent the outflow of
It may be a material.

0012

Effect of the Invention By adopting the above-described measures, the manufacturing method according to the present invention operates as follows. That is,
By forming the outflow prevention dams 30 in advance at each predetermined position of the outer lead member 20b, the outflow of the brazing material 40 is prevented from occurring at the end face of the outflow prevention dam 30 when the inner lead member 20a and the outer lead member 20b are joined. Since this is prevented, no trouble occurs in the subsequent manufacturing process.

[0013]

Embodiment Next, a method of manufacturing a board for mounting electronic components according to the present invention will be explained according to an embodiment shown in the drawings.

FIGS. 1 and 2 show an electronic component mounting board 100 formed using the manufacturing method according to the present invention. First, to explain the structure of this electronic component mounting board 100, the inner lead member 20a is attached to the insulating base material 1.
An outer lead member 2 protrudes outward from the inner lead member 20a and is formed separately from the inner lead member 20a.
0b are connected by a dam bar 21, and a frame-shaped outflow prevention dam 30 is attached to a predetermined position thereof. Each predetermined outer end of the inner lead member 20a and each predetermined inner end of the outer lead member 20b are connected to a brazing material 4 such as solder.
0.

Next, a method of manufacturing this electronic component mounting board 100 will be explained. First, the insulating base material 10 is formed by thermocompression bonding prepreg to both sides of the inner lead member 20a made of copper material so that the inner lead member 20a protrudes outward, using a conventional manufacturing method. A conductor circuit (not shown) is formed on 10 by etching or the like.

Next, an outflow prevention dam 30 is formed on the outer lead member 20b, which is made of copper and connected by the dam bar 21. Here, the outflow prevention dam 30 is formed as a rectangular frame with a height of 0.2 mm using a tape material made of polyimide so that it can be housed in a mold when it is later sealed with a mold resin. Ru.

Next, each predetermined outer end of the inner lead member 20a is positioned at each predetermined inner end of the outer lead member 20b, and a brazing material 40 that is an electrical conductor such as solder is applied.
The outer lead member 20b and the inner lead member 20
a to form electrically and physically integrated leads 20. At this time, the outflow of the brazing material 40 from the joint is prevented by the outflow prevention dam 30.

Finally, the unnecessary outflow prevention dam 30 is peeled off and removed, and the dam bar 21 is cut by punching to obtain the electronic component mounting board 100. In this case, as shown in FIG. 3, the outflow prevention dam 30 is provided at a position that fits within the mold resin to be sealed, so the outflow prevention dam 30 does not necessarily need to be removed.

As shown in FIG. 3, the electronic component mounting substrate 100 formed in this manner is sealed with a molding resin after mounting electronic components thereon, and becomes an electronic component mounting device.

[0020]

As described in detail above, according to the manufacturing method of the present invention, by forming leakage prevention dams in advance at each predetermined position of the outer lead member, the inner lead member and the outer lead member can be easily separated. When bonding with the solder metal, the leakage of the filler metal is prevented by the end face of the leakage prevention dam, and there is no problem in the subsequent manufacturing process, making it easy to manufacture high-quality boards for mounting electronic components. .

[Brief explanation of the drawing]

FIG. 1 is a plan view showing an example of an electronic component mounting board manufactured by a manufacturing method according to the present invention.

FIG. 2 is a sectional view taken along line AA in FIG. 1;

FIG. 3 is a cross-sectional view of an electronic component mounting apparatus constructed using the electronic component mounting board shown in FIG. 1;

FIG. 4 is a cross-sectional view of the electronic component mounting board showing a state in which the brazing material has flowed out.

FIG. 5 is a cross-sectional view of the electronic component mounting board with the brazing material still flowing out and housed in the mold.

[Explanation of symbols]

10 Insulating base material 20 Lead 20a Inner lead member 20b Outer lead member 21 Dam Bar 30 Runoff prevention dam 40 Brazing filler metal (solder) 100 Board for mounting electronic components

Claims (1)

[Claims] Claim 1: A plurality of leads are formed by integrally joining an inner lead member and an outer lead member, which are formed separately, with a brazing material such as solder, and each lead is provided on both sides of these leads. 1. A method of manufacturing a substrate for mounting an electronic component, which has an insulating base material integrally formed so as to protrude in the direction, the method of manufacturing a substrate for mounting an electronic component, the manufacturing method comprising the following steps: . (b) Forming outflow prevention dams for preventing the outflow of the brazing material at each predetermined position of the outer lead member; (b) At each predetermined outer end of the inner lead member and each predetermined inner part of the outer lead member. A step of forming each lead by joining the ends with the brazing material.