JPH09219485A - Manufacture of substrate for loading electronic component - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the manufacture of a substrate, in which a bent stepped section is bent and formed accurately to a lead and the deformation of a frame section for fixing the lead can be inhibited and which is used for loading an electronic component. SOLUTION: When bent stepped sections 12 are formed to a large number of leads 10, in which joining end sections 11 are joined around a substrate 2, the joining end sections 11 of the leads 10 are connected to the lands 22 of through-holes 20 shaped to the substrate 2. The leading-out sections 13 of the leads are arranged between the plane section 310 of a top force 31 and the plane section 320 of a bottom force 32. Pushing load is applied to the substrate 2 by a punch 30, the leads 10 are deformed along the side face of the substrate 2, and the bent stepped sections 12 are formed. It is preferable that the above-mentioned pushing load is applied under the state, in which a reinforcing resin is bonded and covered so as to cover the surfaces of the joining end sections 11.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for manufacturing an electronic component mounting substrate, and more particularly to a method for forming a bent step portion on a lead.

[0002]

2. Description of the Related Art Conventionally, as a substrate for mounting an electronic component, for example, as shown in FIG. 13, there is one in which a large number of leads 10 are bonded to the periphery of a substrate 2 (JP-A-5-121626, JP-A-5-12626). No. 275599). This lead 1
Reference numeral 0 denotes a joint end portion 11 that is joined to a predetermined position of the conductor circuit 29 of the substrate 2, a bent step portion 12 that is bent in a V shape along the side surface of the substrate 2, and is projected to the outside of the substrate 2. And a drawer portion 13. The substrate 2 is sealed with a sealing resin 6 after mounting the electronic component 8. The reason why the bent step portion 12 is provided on the lead 1 is that the amounts of the sealing resin 6 above and below the substrate 2 are made substantially the same.

Incidentally, in manufacturing the above-mentioned electronic component mounting substrate 7, it has been conventionally done, for example, in Japanese Patent Laid-Open No. 5-275.
There is a method disclosed in Japanese Patent No. 599. That is, first, as shown in FIG. 14, the joining end portion 11 of the lead 10 is joined to a predetermined position of the conductor circuit 29 of the substrate 2. Next, as shown in FIG. 15, in order to form the bending step portion 12, the lead 10 is formed.
The lead-out portion 13 and the portion where the bent step portion 12 is to be formed are arranged between the upper die 91 and the lower die 92.

The lower die 92 has a recess 920 for pressing the bending step 12 from below, while the upper die 91 has a bending step 1
2 has a convex portion 910 that receives the upper surface. Next, lower mold 9
The bending step portion 12 is formed between the joining end portion 11 and the lead portion 13 by pressing the upper part 2 against the upper mold 91. Then, as shown in FIG. 13, the electronic component 8 is mounted on the mounting portion 25 of the substrate 2. Next, the electronic component 8 and the conductor circuit 29
A wire 81 is connected between Next, these are sealed with a sealing resin 6 to obtain the electronic component mounting substrate 7.

[0005]

By the way, in recent years, it is necessary to reduce the length C of the bending step portion 12 of the lead 10 while the miniaturization of the electronic component mounting substrate is required. However, in the conventional method of manufacturing a board for mounting electronic components, the bending step portion 12 is formed by the convex portion 910 of the upper die 91 and the concave portion 92 of the lower die 92.
It was formed by 0 and. Therefore, in reducing the length C of the bending step portion 12, the convex portion 910 and the concave portion 92 are
Although 0 must be formed accurately, there is a limit to the accuracy of the shapes of both.

The shape of the bent step portion of the lead is determined by the fitting state of the convex portion 910 of the upper die 91 and the concave portion 920 of the lower die 92. Therefore, it is necessary to fit them correctly. However, there is a limit to the accuracy with which they can be fitted together.
Therefore, in the above-mentioned conventional method, it is difficult to accurately bend and form the bending step portion 12. In addition, the bending step portion 12 may be deformed by bending, because the frame portion integrally fixing the large number of leads 10 is pulled inward and the frame portion is deformed (see FIG. 7).

In view of the above conventional problems, the present invention is a method for manufacturing a board for mounting electronic parts, in which a bent step portion can be accurately bent and formed on a lead and deformation of a frame portion for fixing the lead can be suppressed. Is to provide.

[0008]

According to a first aspect of the present invention, there is provided a substrate on which a conductor circuit is provided, and a large number of leads whose joint ends are joined to the periphery of the substrate, wherein the leads are side surfaces of the substrate. In manufacturing an electronic component mounting board provided with a bent step portion bent in a V shape along a line and a lead-out portion protruding to the outside of the board, first, in a conductor circuit of the board, a lead frame is formed. The lead ends of all of the leads are placed between the flat surface of the upper mold and the flat surface of the lower mold, and then punched on the substrate. A method for manufacturing an electronic component mounting substrate, characterized in that the lead is deformed along a side surface of the substrate by applying a pressing load to form the bent step portion.

In the above-mentioned method of manufacturing the electronic component mounting board, the lead-out portion joined to the lower surface of the board is arranged between the flat portions of the upper die and the lower die. In this state,
When a pressing load is applied to the substrate from above, it bends in a convex shape at the end of the lower mold and in a concave shape at the end of the side surface of the substrate, and a bending step is formed between the two bending points.

The bending step of the lead can accurately control the bending condition of the lead by the moving distance of the punch and the pressing force applied to the lead. For example, when a copper lead is used, as shown in FIG. 9, the pressing load at the yield point of the copper lead is 588 N / mm ² (60 kgf /
mm ² ). Therefore, by applying a pressing load larger than this yield point to the lead, it is possible to give the lead permanent set.

Then, as shown in FIG. 9, when the elongation percentage of copper is within the range of approximately 1.5% to 12%, the lead can be permanently strained without being broken. The rate of elongation of the lead is directly proportional to the downward movement distance of the punch. Therefore, the bending condition of the lead can be accurately controlled by the moving distance of the punch.

When the punch is pressed, the lead lead-out portion is held between the upper die and the lower die. Therefore, the pressing force of the punch is absorbed by the lead wire and the upper die and the lower die that hold the lead wire, and does not affect the frame portion that fixes one end of the lead portion. Therefore,
The frame portion for fixing the leads is not deformed.

Further, due to the pressing load of the punch, a bent step portion is formed outward from the side end portion of the substrate.
Therefore, the distance between the side end portion of the substrate and the lead-out portion can be shortened, and the electronic component mounting substrate can be miniaturized.

Further, the upper die and the lower die are provided with flat portions which are easy to form. Therefore, the upper mold and the lower mold can be manufactured at low cost. Further, in the upper mold and the lower mold, since the leads are arranged between the flat portions of both, it is not necessary to consider the fitted state of the both as in the conventional case. Therefore, the bent step portion can be formed easily and inexpensively.

Next, as described in claim 2, after joining the joining end portion of the lead to the conductor circuit of the substrate, a reinforcing resin is applied to the substrate so as to cover the surface of the joining end portion. It is preferable to apply an adhesive coating and then apply the pressing load to the substrate. As a result, the joining ends of the leads are securely joined to the substrate, and the leads are not removed from the substrate when pressed by the punch.

The above-mentioned reinforcing resin is characterized in that it has few ionic impurities, does not contaminate electronic parts, has heat resistance to temperatures of 200 to 250 ° C., and does not soften when electronic parts are mounted. preferable. As the reinforcing resin, for example, high-purity epoxy resin or polyimide resin is used.

Next, as described in claim 3, between the inner surface of the lower mold and the outer surface of the substrate, 1.0 to 1.
It is preferable that a space of 5 mm is provided. As a result, the lower die is bent in a convex shape and the side edge of the substrate is bent in a concave shape. A bent step portion that is linearly inclined along the side surface of the substrate is formed between the lower mold and the substrate. Therefore, the leads are uniformly extended over the entire bending step, and there is no risk of the leads being cut.

On the other hand, if the space between the inner surface of the lower die and the outer surface of the substrate is less than 1.0 mm, the leads may be broken during pressing. On the contrary, the space is 1.5m
When it exceeds m, the bent step portion protrudes outside the molding die for the sealing resin, so that the sealing resin may not be molded.

The step x of the bent step portion is preferably about half the thickness of the electronic component mounting board. Thus, when the front and back surfaces of the electronic component mounting board are covered with the sealing resin, the lead wire of the lead can be projected from the center of the sealing resin. Further, the sealing resin can be coated on both sides of the electronic component mounting substrate to a uniform thickness.

Next, as described in claim 4, the conductor circuit is, for example, a land of a through hole provided in the substrate. Further, the conductor circuit may be a wiring pattern formed on the surface of the substrate or a terminal.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION

First Exemplary Embodiment A method for manufacturing an electronic component mounting substrate according to an exemplary embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 8, the electronic component mounting board 7 manufactured according to this example includes a board 2 provided with a conductor circuit and a large number of leads 10 having joint ends 11 connected to the periphery of the board 2. The lead 10 is provided with a bent step portion 12 that is bent in a V shape along the side surface of the substrate 2 and a lead portion 13 that is projected to the outside of the substrate 2.

The conductor circuit provided on the substrate 2 includes a metal plating film 23 provided inside the through hole 20, a land 22 provided at the upper and lower peripheral edges of the through hole 20, and a through hole 20 to a mounting portion 25. The wiring pattern 21 extends in the direction. The electronic component 8 is mounted on the mounting portion 25. A wire 81 connects the electronic component 8 and the wiring pattern 21. The substrate 2 is covered with a sealing resin 6 so as to seal the electronic component 8.

Next, a method of manufacturing the electronic component mounting board 7 will be described. First, as shown in FIG. 1, a through hole 20 is formed in a substrate 2 made of glass epoxy resin,
A metal plating film 23 (Ni / Au) is formed inside thereof, and lands 22 are formed by Ni / Au plating on the peripheral edges of the upper and lower openings. Also, on the surface of the substrate 2, copper foil and Ni
/ Au plating film for wiring pattern 21 and mounting portion 25
To form Next, as shown in FIG. 1, a thermosetting epoxy resin adhesive 40 is placed on the peripheral edge of the upper surface of the substrate 2.

Further, as shown in FIG.
A lead frame 1 having a large number of leads 10 provided therein is prepared. A fixing hole 199 is formed in the frame portion 19. Next, as shown in FIGS. 2 and 3, the joint end portion 11 of the lead 10 is placed on the land 22 provided on the surface 26 of the substrate 2. At this time, the bonding end portion 11 of the lead 10 is bonded to the surface of the substrate 2 by the adhesive 40,
Fixed.

Next, as shown in FIGS. 4 and 5, the solder 4 melted from below the through hole 20 is filled with the molten solder 4.
Supply within. Then, the solder 4 is used to join the joining end 11 of the lead located above the through hole 20 and the land 22.

Next, as shown in FIG. 6, an upper die 31 and a lower die 32 for forming a bent step portion on the lead 10 and a punch 30 arranged so as to be vertically movable inside the upper die 31 are prepared. To do. The upper die 31 and the lower die 32 are provided with flat portions 310 and 320 for arranging the lead portion 13 of the lead 10. The punch 30 is provided with a flat surface portion 300 for pressing the substrate 2.

Next, the lead portions 13 of all the leads 10 are arranged between the flat portions 310 and 320 of the upper die 31 and the lower die 32. At this time, the inner surface 320 of the lower mold 32
A space A corresponding to the length B of the bent step portion 12 of the lead 10 is provided between and the outer surface 200 of the substrate 2. This space A is 1.0 mm.

Next, the punch 30 is moved downward by 0.7 mm while applying a pressing load of 60 kgf / mm ² by the flat surface portion 300 of the punch 30 to the back surface 27 opposite to the surface 26 to which the lead 10 is bonded, with respect to the substrate 2. Press to move.
As a result, the substrate 2 is pushed downward, and the leads 10 bonded to the lower surface of the substrate 2 bend in a concave shape at the side end 29 of the substrate 2 and in a convex shape at the end 329 of the lower mold 32, As shown in FIG. 7, two bending points 121 and 12
Form 2

A bent step portion 12 which is bent along the side surface of the substrate 2 is formed between the bent points. The step x of the bent step portion 12 is 0.2 mm, which is approximately half the thickness of the electronic component mounting substrate of 0.4 mm (excluding the sealing resin). As a result, the electronic component mounting substrate 7 shown in FIG. 7 is obtained. After that, as shown in FIG. 8, the electronic component 8 is mounted on the mounting portion 25, and the wire 81 connects the electronic component 8 and the wiring pattern 21. Next, electronic parts 8
The entire surface of the substrate 2 is covered with a sealing resin 6 so as to seal the substrate.

Next, the operation and effect of this embodiment will be described.
In the method of manufacturing the electronic component mounting board, as shown in FIG. 6, the bending degree of the lead 10 can be accurately controlled by the moving distance of the punch 30 and the pressing force applied to the lead 10.

When the punch 30 presses, the lead lead-out portion 13 is sandwiched by the upper die 31 and the lower die 32. Therefore, the pressing force of the punch 30 is applied to the lead wire 13 and the upper die 31 and the lower die 32 that sandwich the lead wire 13.
The frame portion 19 for fixing the lead-out portion 13 is not deformed by being absorbed by.

Further, due to the pressing load of the punch 30,
The step portion 12 is bent outward from the side end 29 of the substrate 2.
Is formed. Therefore, the length B of the bent step portion 12 of the substrate 2 can be shortened, and the electronic component mounting substrate 7 can be downsized.

Further, the upper die 31 and the lower die 32 are provided with flat portions 310 and 320 which are easy to form. for that reason,
The upper mold and the lower mold can be manufactured at low cost. Further, since the lead 10 is arranged between the flat portions 310 and 320 of the upper die 31 and the lower die 32, it is not necessary to consider the fitted state of the two as in the conventional case. Therefore, the bending step 1
2 can be easily formed at low cost.

Embodiment 2 In the electronic component mounting substrate of this embodiment, as shown in FIG. 12, the surface of the joint end portion 11 of the lead 10 is covered with the reinforcing resin 5, as shown in FIG. Different from 1. As the reinforcing resin 5, high-purity epoxy resin or polyimide resin is used.

In manufacturing the electronic component mounting substrate, first, as shown in FIG. 10, the lead 10 is bonded to the substrate 2 with the adhesive 40 as in the first embodiment.
Further, the solder 4 supplied into the through hole 20 joins the joining end 11 of the lead 10 to the land 22 provided on the surface 26 of the substrate 2. Then, as shown in FIG. 10, the reinforcing resin 5 is formed so as to cover the surface of the joint end 11 of the lead 10.
Is coated on the substrate 2 with adhesive.

Then, as shown in FIG. 11, the lead portion 13 of the lead 10 is arranged between the flat portions 310 and 320 of the upper die 31 and the lower die 32, and the lead 10 is attached to the substrate 2.
The punch 30 is attached to the back surface 27 opposite to the front surface 26 where the
The punch 30 is moved downward by 0.7 mm while applying a pressing load of 60 kgf / mm ² by the flat surface portion 300. As a result, the bending step portion 12 is formed between the side surface end portion 29 of the substrate 2 and the end portion 329 of the lower die 32.

In this example, the joining end portion 1 of the lead 10 is
In the state where the reinforcing resin 5 is adhesively coated on the substrate 2 so as to cover the surface of 1, the pressing load is applied. for that reason,
The joining end 11 is reliably joined to the substrate 2. Therefore, the lead 10 is not removed from the substrate 2 when pressed by the punch 30. Therefore, the conduction between the through hole 20 and the lead 10 can be reliably ensured. Other,
Also in this example, the same effect as in the first embodiment can be obtained.

[0038]

According to the present invention, there is provided a method for manufacturing an electronic component mounting substrate, which is capable of accurately forming a bending step portion on a lead and suppressing deformation of a frame portion for fixing the lead. be able to.

[Brief description of drawings]

FIG. 1 is a sectional view of a substrate according to a first embodiment.

FIG. 2 is a cross-sectional view of the substrate to which the leads are bonded according to the first embodiment.

FIG. 3 is a plan view of the substrate to which the leads are bonded according to the first embodiment.

FIG. 4 is a cross-sectional view of the substrate in which the land of the through hole and the joint end portion of the lead are joined by solder in the first embodiment.

FIG. 5 is a partial plan view of the substrate in which the land of the through hole and the joining end portion of the lead are joined by solder in the first embodiment.

FIG. 6 is an explanatory view showing a method of forming a bent step portion on a lead by pressing a punch in the first embodiment.

FIG. 7 is a cross-sectional view of the electronic component mounting board according to the first embodiment.

FIG. 8 is a cross-sectional view of an electronic component mounting board in which an electronic component is sealed with a sealing resin according to the first embodiment.

FIG. 9 is a diagram showing the relationship between the pressing load on copper and the elongation rate of copper.

FIG. 10 is a cross-sectional view of a substrate in which a joining end portion is covered with a reinforcing resin before being pressed by a punch in the second embodiment.

FIG. 11 is an explanatory view showing a method of forming a bent step portion on a lead by pressing a punch in the second embodiment.

FIG. 12 is a cross-sectional view of an electronic component mounting board in which an electronic component is sealed with a sealing resin according to the second embodiment.

FIG. 13 is a cross-sectional view of an electronic component mounting board in which an electronic component is sealed with a sealing resin in a conventional example.

FIG. 14 is a cross-sectional explanatory view of a substrate to which leads are joined in a conventional example.

FIG. 15 is an explanatory view showing a method of forming a bent step portion on a lead by pressing a punch in a conventional example.

[Explanation of symbols]

 1. . . Lead frame, 10. . . Lead, 11. . . Junction end, 12. . . Bending step, 13. . . Drawer, 19. . . Frame part, 2. . . Substrate, 20. . . Through hole, 22. . . Land, 25. . . Mounting part, 30. . . Punch, 31. . . Upper mold, 32. . . Lower mold, 300, 310, 320. . . Plane part, 4. . . Solder, 40. . . Adhesive, 5. . . Reinforcing resin, 6. . . Sealing resin, 7. . . Electronic component mounting board,

Claims (4)

[Claims] 1. A substrate comprising a conductor circuit and a large number of leads having joint ends joined to the periphery of the substrate,
In manufacturing an electronic component mounting board, the lead is provided with a bent step portion bent in a "V" shape along the side surface of the board and a lead-out portion protruding to the outside of the board. Join the joint ends of many leads provided on the lead frame to the conductor circuit of the board, and then arrange the lead-out portions of all the leads between the upper die flat portion and the lower die flat portion. Then, a pressing load is applied to the substrate by a punch to deform the leads along the side surface of the substrate to form the bent step portion, and a method for manufacturing an electronic component mounting substrate. 2. The method according to claim 1, wherein after joining the joining end portion of the lead to the conductor circuit of the substrate, a reinforcing resin is adhesively coated on the substrate so as to cover the surface of the joining end portion, and thereafter. A method for manufacturing a board for mounting electronic parts, wherein the pressing load is applied to the board. 3. The method according to claim 1, wherein the distance between the inner surface of the lower mold and the outer surface of the substrate is 1.0 to 1.5 m.
A method for manufacturing an electronic component mounting substrate, characterized in that a space of m is provided. 4. The method according to claim 1, wherein
The method for manufacturing an electronic component mounting substrate, wherein the conductor circuit is a land of a through hole provided in the substrate.