JPH08288647A - Manufacture of printed wiring board, and printed wiring board - Google Patents

Abstract

PURPOSE: To provide a manufacturing method of a metal base printed wiring board of low cost having no possibility of warp generation, and a printed wiring board having high reliability of lead soldering. CONSTITUTION: A large circuit board 10A wherein a specific circuit is formed in each division divided in a lattice type, and a plurality of individual metal segment plates 20 equal to the plan visual form of individual segment circuit boards 10 are formed. On the back of the large circuit board 10A, the individual metal segment plates 20 is heated, pressed and stuck via prepreg 4, corresponding to each of the divisions. After a specific electronic component 5 is surface- mounted on each of the individual segment circuit boards 10, the large circuit board 10A is cut and isolated along lines of the lattice. Hence printed wiring boards wherein the individual segment circuit boards 10 and the individual metal segment plates 20 are stacked as a dual layer is formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printed wiring board manufacturing method and a printed wiring board. In electronic devices such as communication devices in recent years, there is a tendency to mount a power supply module for each line (circuit unit). On the other hand, increasing the output of the device,
With the demand for miniaturization and high integration, power supply modules mount electronic components such as transformers, capacitors, and semiconductor components on a printed wiring board equipped with a metal base and radiate heat from these electronic components from the metal base. I am letting you.

[0002]

2. Description of the Related Art A conventional printed wiring board having a metal base is shown in FIG. In the figure, 2 is a metal plate such as aluminum. Reference numeral 3 is a circuit board such as a resin laminated board or a ceramic board provided with pads, patterns, and vias on the surface layer and the inner layer. Lead pads 7 are formed in an array on the surfaces of the opposite side edges of the circuit board 3 along the side edges.

A prepreg 4 is sandwiched between the circuit board 3 and the metal plate 2 and heated and pressed, and the circuit board 3 and the metal plate 2 are laminated and laminated to form a metal base printed wiring board 1. 8
Is an input / output lead made of copper-based metal having a cross-sectional area of, for example, about 1 mm ² . Reference numeral 9 denotes a molded lead holder including a prismatic main body having a length substantially equal to the width of the metal base printed wiring board 1 and a pair of U-shaped legs provided at both ends of the main body. .

A large number of input / output leads 8 are insert-molded and arranged in a line so as to vertically penetrate the main body of the lead holder 9. The protrusion provided on the bottom surface of the leg portion of the lead holder is fitted into the hole of the printed wiring board to be positioned, the leg portion is seated on the end portion of the metal base printed wiring board 1, and the pair of lead holders 9 are attached to the printed wiring board. 1 is crosslinked to the opposite side edges.

When the lead holders 9 are bridged to the printed wiring board 1 as described above, the arrangement pitch is such that the joint surface of the input / output leads 8 comes into contact with the surface of the corresponding lead pad 7.

On the front side of the printed wiring board 1, a transformer,
The electronic parts 5 such as capacitors and semiconductor parts are reflow-soldered and surface-mounted, and at the same time, the joint surface of the input / output lead 8 is reflow-soldered to the surface of the lead pad 7.

As shown in FIG. 11, in the printed wiring board 1 on which the electronic components 5 are surface-mounted as described above, the end portions of the leg portions of the lead holder 9 are brought into contact with the surface of the mother board 100,
The tips of the respective input / output leads 8 are inserted into the corresponding through holes and soldered to be mounted on the motherboard 100.

A printed wiring board provided with such a metal base is required to have a low cost like other printed wiring boards.

[0009]

Therefore, a multi-cavity manufacturing method as shown in FIG. 12 has been attempted. FIG.
In 2, 3A is a large circuit board,
The surface of 3A is divided into areas having the same shape as the desired circuit board, and a predetermined circuit is formed in each area.

Reference numeral 2A is a large metal plate having the same shape as that of the large circuit board 3A, and V-grooves 6 are provided in a lattice pattern on the back surface side so as to be divided into a rectangular shape in accordance with a desired circuit board shape. . Large metal plate
2A is attached to the back side of the large-sized circuit board 3A via the prepreg 4 (heated and pressed to be attached), and then electronic components are surface-mounted on the divided areas of the large-sized circuit board 3A. Then, it was decided to bend it along the V-groove 6 to separate it into individual printed wiring boards.

However, in such a manufacturing method, since the metal material has malleability, even if the large metal plate 2A is bent at the V groove 6 portion, only the bottom portion of the groove 6 extends and bends easily. Does not separate.

Therefore, such a multi-cavity manufacturing method has a problem that it takes a lot of time for the manufacturing work and the cost is high. On the other hand, since the expansion coefficient of the metal plate is larger than the expansion coefficient of the circuit board, a prepreg is sandwiched between the circuit board and the metal plate to heat and press the circuit board and the metal plate together, and then when cooled to room temperature. There was a risk that the printed wiring board would warp. The warped printed wiring board has a problem that it hinders subsequent electronic component mounting work and input / output lead mounting work.

Further, a large metal plate is adhered (heated and pressed to adhere) to the back side of the large circuit board via a prepreg,
If a large warp occurs during cooling to room temperature, a large cutting stress may be applied to the prepreg and the prepreg may be damaged, resulting in delamination between the circuit board and the metal plate.

On the other hand, about 230
When the electronic component is reflow-soldered by heating at a temperature of ℃, a warp occurs due to the expansion coefficient of the metal plate being larger than that of the circuit board.

Therefore, as shown in FIG. 13, a gap is created between the bonding pad of the input / output lead 8 arranged in the central portion of the lead holder 9 and the lead pad 7, and the input / output lead 8 and the lead pad are connected. There was a risk that the reliability of reflow soldering with No. 7 would deteriorate.

Further, in the case of a printed wiring board for a power supply module, a wide range of power supply patterns are required on the surface layer, and this power supply pattern has a problem in that high density mounting of components is hindered.

The present invention has been made in view of the above circumstances, and provides a method of manufacturing a printed wiring board which is free from warpage in a printed wiring board having a metal base and which is low in cost. It is an object.

Another object of the present invention is to provide a printed wiring board provided with a metal base which promotes high density mounting of components. Furthermore, a printed wiring board provided with a metal base having input / output leads with high reliability of soldering is provided.

[0019]

In order to achieve the above object, the present invention, as illustrated in FIG. 1, partitions the surface into a grid pattern to set the areas of the individual circuit boards 10, and A large circuit board (10A) in which a predetermined circuit is formed in the compartment and a plurality of individual metal plates (20) having the same planar view shape as the individual circuit board (10) are provided.

On the back side of the large-sized circuit board 10A, the individual metal plates 20 are heated and pressed through the prepreg 4 and attached to the individual circuit boards 10 corresponding to the respective sections.
A printed wiring board in which a large-sized circuit board 10A is separated and cut along a grid line after a predetermined electronic component 5 is surface-mounted thereon, and individual circuit boards 10 and individual metal plates 20 are stacked. Shall be provided.

In addition, the large-sized circuit board 10A has a lattice-shaped V groove 6
The area of the individual circuit board 10 is set by setting
It is assumed that 10A is bent along the V groove 6 and fractured to separate it into individual metal base printed wiring boards.

As illustrated in FIG. 2, a plurality of individual circuit boards 10 on which a predetermined circuit is formed and a plurality of individual circuit boards 10 and a lattice-shaped slit 21 on the front surface side or the rear surface side are provided.
Large metal plate 20A divided into areas equal to the plan view shape of
Are provided.

Corresponding to each section on the surface of the large-sized metal plate 20A, the individual circuit boards 10 are heated and pressed through the prepregs 4 to be adhered to each other, and the predetermined circuit boards 10 are attached to the individual circuit boards 10. After mounting the electronic component 5 on the surface, irradiating the bottom of the slit with a laser to separate and cut the large metal plate to provide a printed wiring board in which the individual circuit board 10 and the individual metal plate 20 are laminated. And

As illustrated in FIG. 3, a plurality of substrate strips 30.
The circuit board 30 divided into -1 is laminated on the metal plate 40 in multiple layers, and the pattern between the board strips 30-1 has the electronic component 5 or the bonding wire 15 bridged between the board strips 30-1. The printed wiring board is electrically connected to the printed wiring board through the wiring board.

As illustrated in FIG. 4, a metal plate 40 having a groove 41 on the upper surface side, a covered electric wire 50 inserted and fixed in the groove 41 so that both ends bend upward, and a terminal of the groove 41 A circuit board (30) having through holes (31) facing each other and laminated on the front surface side of a metal plate (40) is provided.

In the covered electric wire 50, the end portion where the core material 51 is exposed is inserted and soldered into the through hole 31, and the through hole 31 is provided with the power source pattern 31A provided on the circuit board 30.
The printed wiring board is provided at the terminal of.

As illustrated in FIG. 5, a circuit board 30 having a metal plate 40 having a stepped hole 43 and a through hole 35 opposed to the stepped hole 43 and being laminated on the front surface side of the metal plate 40. And is inserted into the stepped hole 43 via an insulator, and the tip is a through hole 35.
And a pin-shaped input / output lead 60 to be inserted and soldered in.

The through hole 35 is provided at the end of the input / output pattern 35A provided on the circuit board 30. As illustrated in FIG. 6, a metal plate 40 having screw holes 45 and screw holes 45
Circuit board 30 having counterbored holes 44 facing each other and laminated on the surface of metal plate 40, and lead lands formed around the front surface of counterbored holes 44 and connected to terminals of input / output pattern 37A. 37, an input / output lead 70 formed of a pin-shaped lead portion 71 and a head portion 72 provided at one end of the lead portion 71, and a base portion of the lead portion 71 and screwed into a screw hole 45 of a metal plate 40. And an insulator screw 73 for

The input / output lead 70 has a structure in which the lower surface of the head 72 is in close contact with the lead land 37 and soldered. Figure 7
As illustrated in FIG. 3, the circuit board 30 laminated on the front surface side of the metal plate 40, and the hole 77 penetrating the circuit board 30 and the metal plate 40.
A lead land 37 formed around the surface of the circuit board 30 in the hole 77 and connected to the end of the input / output pattern 37A; a pin-shaped lead portion 75A; and a collar 75B provided near one end of the lead portion 75A. And an insulating bush 76 fixed to the end surface of the collar 75B opposite to the lead portion 75A and press-fitted into the hole 77.

The input / output lead 75 is configured such that the outer peripheral portion of the end surface of the collar 75B is in close contact with the lead land 37 and soldered. A metal plate having a side wall 40A-1 as illustrated in FIG.
40A, the circuit board 30A made of a film or ceramics laminated on the surface side of the metal plate 40A including the surface of the side wall 40A-1, and the input / output pattern 38A formed on the surface of the circuit board 30A. , Side wall surface 30A of circuit board 30A-
1 has lead pads 38 arranged in an array, and an input / output lead 80 vertically provided on the metal plate 40 by soldering one end of the lead pads 38 to each other.

As illustrated in FIG. 9, the circuit board 30 is laminated on the surface of the metal plate 40, the lead pads 7 are formed on the surface of the circuit board 30 along the side edges, and the circuit board is formed.
Insulation consisting of a prismatic main body with a length approximately equal to the width of 30 and a pair of U-shaped legs provided at both ends of the main body, with through holes vertically penetrating the main body being arranged. And a lead holder 90 composed of a body.

Further, the through-hole 91 with the through-hole 91 being penetrated
The pin-shaped input / output lead 8 is fixed to the lead holder 90 by the adhesive 92 filled in the lead holder 90, and the joining surface at the tip abuts the lead pad 7 and is soldered.

The lead holder 90 is mounted so that the legs are seated on both ends of the circuit board 30 so as to bridge the circuit board 30, and the input / output lead 8 and the lead holder 90 are bonded and fixed. The adhesive 92 has a softening point of the lead pad 7
The temperature is lower than the reflow temperature of the solder that joins the I / O lead 8 with the input / output lead 8.

[0034]

According to the method of the present invention, the individual metal plates are laminated on the back side of the large-sized circuit board or the individual circuits are attached to the front side of the large-sized metal plate which is easily separated. This is a multi-cavity method in which the bonding area between the metal plate and the circuit board is reduced in a state before the boards are attached in multiple layers and separated into printed wiring boards having individual metal bases.

Since the bonding area between the metal plate and the circuit board is small as described above, the prepreg is sandwiched between the circuit board and the metal plate to heat and press to bond them, and then the printed circuit board is cooled even at room temperature. Almost no warp occurs.

Therefore, the electronic component mounting work or the input / output lead mounting work is not hindered. on the other hand,
Since the method of the present invention is a multi-cavity manufacturing method, the printed wiring board provided with the obtained metal base is inexpensive.

The circuit board made up of a plurality of board strips is particularly applied to a printed wiring board having a large metal base to suppress the occurrence of warpage. A metal-based printed wiring board with a covered wire for power supply circuit wired in the groove of the metal plate can shorten the length of the power supply pattern provided on the surface layer, so that the mounting area for components is substantially large. Become. Therefore, high-density mounting is promoted.

In the printed wiring board having the input / output lead structure according to claims 6 to 9, the input / output leads are connected to the input / output pattern of the printed wiring board in a state where they are individually separated. This is a structure in which the input / output pattern is soldered to the input / output pattern regardless of the presence or absence of warpage.

Therefore, the reliability of the soldering of the input / output leads is high. 11. The printed wiring having the input / output lead structure according to claim 10, wherein the softening point of the adhesive that bonds and fixes the input / output lead and the lead holder is lower than the reflow temperature of the solder that joins the lead pad and the input / output lead. When the plate is heated when the input / output lead is reflowed to the lead pad, the adhesive that bonds and fixes the input / output lead and the lead holder is softened, and the input / output lead can move in the axial direction. In this state, the suction force of the reflow solder is applied, so that the input / output leads shift in the through holes of the lead holder and descend toward the lead pads, and the joint surfaces of the input / output leads are soldered to the lead pads. .

Therefore, even if the printed wiring board is warped by being heated during the reflow soldering, or even if the printed wiring board is originally warped, the bonding surfaces of all the input / output leads are the lead pads. Be sure to solder.

Therefore, the reliability of the soldering of the input / output leads is high.

[0042]

The present invention will be described in detail with reference to the drawings. The same reference numerals indicate the same objects throughout the drawings.

FIG. 1 is a diagram showing an embodiment of the method of the present invention.
Is a perspective view, (B) is a sectional view, FIG. 2 is a view showing steps of another embodiment of the method of the present invention, FIG. 3 is a view of one embodiment of the printed wiring board of the present invention, and FIG. 4 is a power supply circuit. FIG.

FIG. 5 is a diagram of an embodiment of the lead, FIG. 6 is a diagram of the invention of claim 7, (A) is a diagram before mounting, and (B) is a diagram after mounting. 7 is a diagram of the invention of claim 8, (A) is a diagram before mounting, (B) is a diagram after mounting, FIG. 8 is a perspective view of the invention of claim 9, and FIG. It is sectional drawing of the invention of Claim 10.

In FIG. 1, reference numeral 10A denotes a V-shaped groove 6 cut in a lattice shape to partition the surface into a shape equal to the shape of the desired individual circuit board 10 in plan view, and a pad, a pattern, a beer, etc. in each partition. Is a large-sized circuit board made of a resin laminated board or a ceramics board provided with a predetermined circuit.

Reference numeral 20 is an individual metal plate made of metal such as aluminum and having a rectangular plate shape which is equal to the planar view shape of the individual circuit board 10. The individual metal plate 20 is attached to the rear surface of the large-sized circuit board 10A by heating and pressing it through the prepreg 4 corresponding to each section. Thereafter, a predetermined electronic component 5 is reflow-soldered and surface-mounted on each individual circuit board 10.

Then, the large-sized circuit board 10A is bent and broken along the V groove 6, the individual circuit board 10 is laminated on the individual metal plate 20, and the electronic component 5 is placed on the surface of the individual circuit board 10. Separate into printed wiring boards with mounted metal base.

When the V-groove 6 is not provided, the large circuit board 10A is separated and cut along the lines of the lattice by using a cutter or the like. The above-described multi-cavity manufacturing method has high circuit forming work efficiency of a circuit board and surface mounting work efficiency of parts, and is mass-produced, and a printed wiring board provided with the obtained metal base is inexpensive.

Further, the large circuit board and the large metal plate are not laminated to each other, but the individual metal plate 20 divided into small pieces is adhered to the large circuit board 10A to reduce the joint area. There is. Therefore, the prepreg is sandwiched between the circuit board and the metal plate, heated and pressed to bond, cooled, and at room temperature, the printed wiring board hardly warps.

Therefore, the electronic component mounting work or the input / output lead mounting work is not hindered. In FIG. 2, reference numeral 10 is an individual circuit board in which large-sized circuit boards are provided with lattice-shaped V grooves and are divided into predetermined shapes, predetermined circuits are formed in the respective divisions, and then bent along the V grooves. Is.

Reference numeral 20A is a large metal plate 20A having slits 21 in the form of a grid on the surface side, and the surface of which is divided into a plurality of regions having the same shape as the individual circuit board 10 in plan view. And Figure 2
As shown in (A) of Fig. 4, the individual circuit board 10 is attached to the surface of the large metal plate 20A in accordance with each section by the prepreg 4.
Apply heat by pressing through. Therefore,
Gap 11 between the arranged individual circuit boards 10 and large metal plate 20A
It coincides with the slit 21 provided in.

After that, as shown in FIG. 2B, predetermined electronic components 5 are surface-mounted by reflow soldering on the individual circuit boards 10. Next, the bottom of the slit 21 is irradiated with a laser to separate and cut the large metal plate 20A,
As shown in (C), the individual metal plate 20 and the individual circuit board 10
Is a multi-layered printed circuit board, and a printed wiring board is provided with a metal base on which the electronic components 5 are surface-mounted on the individual circuit board 10.

Such a manufacturing method has substantially the same effect as the manufacturing method shown in FIG. In the metal-based printed wiring board shown in FIG. 3B, the circuit board 30 divided into a plurality of board strips 30-1 is laminated on the metal plate 40.

Then, the patterns between the board strips 30-1 are electrically connected to each other via the electronic component 5 or the bonding wire 15 bridging between the board strips 30-1. The printed wiring board having such a structure is applied to a printed wiring board having a large metal base, and has an effect of suppressing warpage.

Such a large printed wiring board is shown in FIG.
It is manufactured through the process as shown in (A). That is, after forming a predetermined circuit on the circuit board 30,
Cut along the grid-like separation line 26 with a cutter, etc.
Separate to -1. The strips 30-1 of the substrate are attached to the surface of the metal plate 40 by heating and pressing them through the prepreg 4.

After that, the electronic component 5 is surface-mounted, and then the pattern between the board strips 30-1 is connected by the bonding wire 15. In FIG. 4, reference numeral 50 denotes a coated electric wire in which a core material 51 is coated with a coating 52 and has a predetermined length so as to be a circuit element that constitutes a power supply circuit of a printed wiring board. At both ends of the coated electric wire 50, the coating 52 is peeled off to leave the core 51 bare.

The covered electric wire 50 is the metal plate 40 of the printed wiring board.
Both ends are inserted so as to bend upward in a groove 41 provided on the upper surface side, and are fixed in the groove 41 by an adhesive 42 filled in the groove 41.

Through holes are provided at positions corresponding to the ends of the grooves 41.
The circuit board 30 having 31 is laminated on the front surface side of the metal plate 40 with the prepreg 4 interposed therebetween. Core material 51 of coated electric wire 50
The terminal of is projected into the through hole 31 and is soldered (solder 32) to the through hole 31.

The through hole 31 is formed on the circuit board 30.
It is provided on the terminal of the power supply pattern 31A provided on the.
As described above, in the printed wiring board in which the covered electric wire 50 for the power supply circuit is wired in the metal plate 40, the length of the power supply pattern provided on the surface layer can be shortened, so that the mounting area of the component is substantially large. This has the effect of promoting high-density mounting.

The lead structure of a printed wiring board having a metal base will be described below with reference to the drawings. As shown in FIG. 5, the circuit board 30 is laminated on the front surface side of the metal plate 40 via the prepreg 4 to form a printed wiring board.

Through holes 35 are formed along the side edges of the circuit board 30.
Are arrayed. Each through hole 35 is provided in the terminal of the input / output pattern 35A. Reference numeral 43 denotes a stepped hole that vertically penetrates the metal plate 40, which serves as a large diameter portion 43B and an elongated small diameter portion 43A. The stepped holes 43 are arranged and formed in the metal plate 40 so that the large-diameter portion 43B coincides with the lower side of the through hole 35.

Reference numeral 60 is a pin-shaped input / output lead having a collar 61. Reference numeral 66 is an insulating ring made of, for example, heat-resistant synthetic resin, which is press-fitted into the large-diameter portion 43B, and has a hole through which the tip of the input / output lead 60 penetrates in the central portion.

Reference numeral 65 is an insulating sleeve which is made of, for example, rubber and is inserted and attached to the small diameter portion 43A of the stepped hole 43. The insulating sleeve 65 has an axis through which the input / output lead 60 passes. The input / output lead 60 is inserted into the shaft center hole of the insulating sleeve 65 and the hole of the insulating ring 66, and the collar 61 is brought into contact with the lower end surface of the insulating sleeve 65.

The tip of the input / output lead 60 has a through hole.
It projects into 35. The tip of the input / output lead 60 is soldered (solder 36) to the through hole 35. Needless to say, the pin portion of the input / output lead 60 on the side opposite to the printed wiring board is made to project long below the printed wiring board so that it can be inserted and soldered into the through hole of the motherboard 100.

Since the printed wiring board having the above-mentioned input / output lead structure connects the input / output leads to the input / output pattern of the printed wiring board in a state of being separated from each other, it does not matter whether the printed wiring board is warped or not. No input / output pattern
I / O lead 60 can be soldered to 35A.
Therefore, the reliability of the soldering of the input / output leads is high.

Another embodiment is shown in FIG. As shown in FIG. 6A, the circuit board 30 is laminated on the surface side of the metal plate 40 via the prepreg 4 to form a printed wiring board.

Counterbore holes 44 are formed along the side edges of the circuit board 30, and lead lands 37 are provided on the front surface side of each counterbore hole 44. Each lead land 37 is provided at the terminal of the input / output pattern 37A.

Reference numeral 45 is a screw hole provided in the metal plate 40 so as to coincide with the axial center of the counterbore hole 44. Reference numeral 70 denotes an input / output lead composed of a pin-shaped lead portion 71 and a head portion 72 provided at one end of the lead portion 71, and the outer dimensions of the head portion 72 are counterbore holes 44.
Is sufficiently larger than the diameter dimension of.

Reference numeral 73 designates a head part fitted into the counterbore hole 44, and a screw part provided below the head part and screwed into the screw hole 45 on the outer peripheral surface.
73A is an insulating screw threaded with, for example, heat-resistant synthetic resin.

The input / output lead 70 is insert-molded so that the root portion of the lead portion 71 penetrates the shaft center of the insulator screw 73. As shown in FIG. 6 (B), the input / output lead 70 is screwed so that it penetrates, and the insulator screw 73 is attached to the metal plate.
It is screwed into the screw hole 45 of 40 and the lower end face of the head 72 is attached to the circuit board.
The input / output leads 70 are erected on the printed wiring board by being crimped to the surface of 30, that is, the lead land 37.

The head 72 of the input / output lead 70 is soldered (solder 36) to the lead land 37. Incidentally, it goes without saying that the lead portion 71 of the input / output lead 70 is projected long below the metal base printed wiring board so that it can be inserted and soldered into the through hole of the motherboard.

In FIG. 7, 75 is a pin-shaped lead portion 75.
An input / output lead consisting of A and a collar 75B provided near one end of the lead portion 75A. Tsuba 75B on the side opposite to the lead 75A
An insulating bush 76 having an outer diameter smaller than the outer diameter of the collar 75B is fixed to the end surface of the with an adhesive or the like. The length of the insulating bush 76 is substantially equal to the thickness of the metal base printed wiring board.

On the other hand, in the metal base printed wiring board in which the circuit board 30 is laminated on the front surface side of the metal plate 40 via the prepreg 4, the holes 77 into which the insulating bushes 76 are fitted are arranged along the side edges. Has been formed.

Lead lands 37 are provided on the periphery of each hole 77 on the circuit board 30 side. Each lead land 37 is provided at the terminal of the input / output pattern 37A. The insulating bush 76 is fitted in the hole 77, and the end face of the collar 75B is pressure-bonded to the surface of the circuit board 30, that is, the lead land 37, so that the input / output lead 75 is set up on the printed wiring board.

The flange 75B of the input / output lead 75 is soldered (solder 36) to the lead land 37. The printed wiring board shown in FIG. 8 is a metal plate having a side wall 40A-1.
A circuit board 30A made of a film (for example, polyimide resin) or ceramics, in which a predetermined circuit is provided on the surface side of the metal plate 40A including the surface of the side wall 40A-1 using the adhesive 4A, is laminated to the 40A. It was done.

The side wall surface 30A-1 of the circuit board 30A is connected to the input / output pattern 38A formed on the surface of the circuit board 30A.
The lead pads 38 are formed in an array. Reference numeral 80 is an input / output lead that is formed in a comb-tooth shape and arranged at an equal pitch on a lead frame 81 indicated by a chain line.

The input / output lead 80 has a step near the tip. The step portion is engaged with the corner of the printed wiring board, that is, the connecting surface between the lead pad 38 and the input / output pattern 38A,
The side surface of the tip of the input / output lead 80 is brought into close contact with the lead pad 38, and in that state, the input / output lead 80 and the lead pad 38 are
And are soldered.

The lead frame 81 is separated after soldering. The printed wiring board with the above-mentioned input / output lead structure, regardless of whether or not the printed wiring board is warped,
The input / output lead 80 can be soldered to the lead pad 38. Therefore, the reliability of the soldering of the input / output leads is high.

As shown in FIG. 9, the metal base printed wiring board in which the circuit board 30 is laminated on the front surface side of the metal plate 40 through the prepreg 4 has lead pads 7 along the side edges. Are arrayed.

Reference numeral 8 is an input / output lead made of a copper-based metal having a cross-sectional area of, for example, about 1 mm ^{2. The} lower end of the input / output lead is bent at a right angle to provide a bonding surface for seating on the lead pad 7. Reference numeral 90 denotes a molded lead holder including a prismatic main body 95 having a length substantially equal to the width of the printed wiring board, and a pair of U-shaped leg portions 96 provided at both ends of the main body 95. .

The through holes 91 are arranged at equal pitches so as to vertically penetrate the main body 95 of the lead holder 90, the input / output leads 8 are passed through the respective through holes 91, and the adhesive filled in the through holes 91. The input / output lead 8 is fixed to the lead holder 90 by 92.

The softening point of the adhesive 92 is determined by the solder reflow temperature for reflow soldering the joint surface and the lead pad 7 (atmosphere temperature 230 ° C. in the heating furnace for inserting the printed wiring board for reflow soldering). Is low enough,
For example, 150 ℃.

The projection 96A provided on the bottom surface of the leg portion 96 of the lead holder 90 is fitted into the hole of the printed wiring board to be positioned, and the leg portion 96 is seated on the end portion of the printed wiring board, so that the lead holder 90 is fixed. The metal base printed wiring board is bridged to the side edge.

In this state, the joint surface of each input / output lead 8 is in contact with the corresponding lead pad 7.
Then, by reflow soldering, the input / output leads 8 are joined to the lead pads 7.

Since the metal base printed wiring board is originally warped or warped by heating for reflow soldering, the input / output leads 8 in the central portion are joined because of the above-mentioned structure. Even if the surfaces are not in contact with the opposing lead pads 7, the adhesive 92 that fixes the input / output lead and the lead holder to each other is softened, and the input / output lead can move in the axial direction. In this state, the suction force of the reflow solder 39 is applied, so that the input / output leads are displaced in the through holes 91 of the lead holder and descend toward the lead pads, and the joint surfaces of the input / output leads are soldered to the lead pads. To be done.

Therefore, the reliability of the soldering of the input / output leads is high.

[0087]

Since the present invention is constituted as described above, it has the following effects.

The printed wiring board provided with the metal base obtained by the method of the present invention is less likely to warp.
Therefore, the surface mounting work of components and the soldering work of the input / output leads are facilitated.

Further, since a large number of printed wiring boards can be easily manufactured at the same time, the printed wiring boards are inexpensive. A printed wiring board provided with a metal base in which a circuit board is an assembly of a plurality of board strips is applied to a large-sized printed wiring board, and the occurrence of warpage is suppressed.

In a printed wiring board having a metal base in which a coated electric wire for a power supply circuit is laid in the groove of the metal plate, the length of the power supply pattern provided on the surface layer can be shortened. The area is substantially increased, which is effective in promoting high-density mounting of components.

In the printed wiring board having the input / output lead structure according to claims 6 to 9, the input / output pattern can be soldered to the input / output pattern regardless of whether or not the printed wiring board is warped. The reliability of lead soldering is improved.

A printed wiring board equipped with a metal base having a softening point of an adhesive for bonding and fixing the input / output lead and the lead holder lower than the melting point of the solder for joining the lead pad and the input / output lead is The input / output pattern can be soldered to the input / output pattern regardless of whether or not the printed wiring board is warped, and the reliability of the soldering of the input / output lead is improved.

[Brief description of drawings]

FIG. 1 is a diagram of an embodiment of the method of the present invention, in which (A) is a perspective view,
(B) is a sectional view.

FIG. 2 is a diagram showing steps of another embodiment of the method of the present invention.

FIG. 3 is a diagram of an embodiment of a printed wiring board according to the present invention.

FIG. 4 is a diagram showing a power supply circuit.

FIG. 5 is a diagram of an example of a lead.

FIG. 6 is a diagram of the invention of claim 7, (A) a diagram before mounting, and (B)
Is a diagram after mounting.

FIG. 7 is a diagram of the invention of claim 8, (A) a diagram before mounting, (B)
Is a diagram after mounting.

FIG. 8 is a perspective view of the invention of claim 9;

FIG. 9 is a sectional view of the invention of claim 10;

FIG. 10 is a view of a conventional printed wiring board, (A) is a sectional view, and (B) is a perspective view.

FIG. 11 is a mounting view of a printed wiring board.

FIG. 12 is a diagram illustrating a conventional manufacturing method.

FIG. 13 is a cross-sectional view of a conventional lead portion.

[Explanation of symbols]

 1 Printed wiring board 2,40,40A Metal plate 2A, 20A Large metal plate 3,30,30A Circuit board 3A, 10A Large circuit board 4 Prepreg 4A Adhesive 5 Electronic component 7,38 Lead pad 8,60, 70,75,80 I / O lead 9,90 Lead holder 10 pieces Circuit board 11 Gap 15 Bonding wire 21 Slit 30-1 Board strip 31,35 Through hole 31A Power supply pattern 35A, 37A, 38A I / O pattern 37 For lead Land 43 Stepped hole 45 Screw hole 50 Insulated wire 65 Insulation sleeve 66 Insulation ring 73 Insulator screw 76 Insulation bush 81 Lead frame 90 Lead holder 92 Adhesive 100 Motherboard

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Kinko Sandai 1015 Kamiodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa 1015 Uedota, Fujitsu Limited (72) Inventor Shigeru Goto 1015, Uedaka, Nakahara-ku, Kawasaki, Kanagawa

Claims (10)

[Claims] 1. A large-sized circuit board in which a surface of the circuit board is divided into grid areas to set regions of individual circuit boards, and a predetermined circuit is formed in each area. A plurality of equal individual metal plates are provided, and on the back surface side of the large-sized circuit board, corresponding to each section,
The individual metal plates are heated and pressed through a prepreg to be adhered to each other, and after predetermined electronic components are surface-mounted on each individual circuit board, the large circuit board is attached along the grid lines. Cut it apart,
A method of manufacturing a printed wiring board, comprising: providing a printed wiring board in which the individual circuit board and the individual metal plate are laminated. 2. The large-sized circuit board is provided with lattice-shaped V-grooves to set a region of the individual circuit board, and the large-sized circuit board is bent along the V-grooves to be broken and separated. The method for manufacturing a printed wiring board according to claim 1. 3. A plurality of individual circuit boards, each having a predetermined circuit formed therein, and a front surface side or a rear surface side of the circuit board, which are divided into regions having a shape in plan view of the individual circuit boards by lattice slits. A large metal plate is provided, and the individual circuit boards are adhered by heating and pressing the individual circuit boards through prepregs corresponding to the respective sections on the front surface side of the large metal plate. After surface-mounting a predetermined electronic component on a board, the bottom of the slit is irradiated with a laser to separate and cut the large metal plate, and the individual circuit board and the individual metal plate are laminated. A method of manufacturing a printed wiring board, comprising providing a printed wiring board. 4. An electronic component or a circuit board in which a circuit board divided into a plurality of board strips is laminated on a front surface side of a metal plate, and a pattern between the board strips is cross-linked between the board strips. A printed wiring board, which is electrically connected via a bonding wire. 5. A metal plate having a groove on the upper surface side, a covered electric wire inserted and fixed in the groove so that both ends bend upward, and a through hole facing the end of the groove, A circuit board laminated on the front surface side of a metal plate, wherein the covered electric wire is obtained by inserting and soldering a terminal portion where a core material is bare into the through hole, and the through hole is A printed wiring board, which is provided at a terminal of a power supply pattern provided on a circuit board. 6. A circuit board having a metal plate having a stepped hole, a through hole facing the stepped hole, and being laminated on the surface side of the metal plate, and the stepped via an insulator. A pin-shaped input / output lead which is inserted into the mounting hole and whose tip is inserted and soldered into the through hole; the through hole is provided at the end of the input / output pattern provided on the circuit board. A printed wiring board characterized by the above. 7. A metal plate having a screw hole, a counterbore hole facing the screw hole, and a circuit board laminated on the front surface side of the metal plate, and a circuit board on the front surface side of the counterbore hole. An input / output lead formed around the lead and connected to the end of the input / output pattern, a pin-shaped lead portion and a head provided at one end of the lead portion, and a lead portion fitted to the root portion of the lead portion. And an insulator screw that is screwed into a screw hole of the metal plate, and the input / output lead is soldered to the lead land with the lower surface of the head in close contact with the lead land. A printed wiring board characterized by being a thing. 8. A circuit board laminated on the surface side of a metal plate, a hole penetrating the circuit board and the metal plate, and an input / output pattern formed around the hole on the surface side of the circuit board. An input / output lead consisting of a lead land to be connected to the terminal, a pin-shaped lead portion, and a flange provided near one end of the lead portion, and fixed to an end surface of the flange opposite to the lead portion, An insulating bush press-fitted into the hole, wherein the input / output lead is soldered in a state where an outer peripheral portion of an end surface of the collar is in close contact with the lead land. 9. A metal plate having a side wall, a circuit board made of a film or ceramics, which is fixed in multiple layers on the surface of the metal plate including the surface of the side wall, and an input / output pattern formed on the surface of the circuit board. Input / output vertically arranged on the metal plate with lead pads arrayed on the side wall surface of the circuit board and soldered so that the side surface of one end is in close contact with the lead pad. A printed wiring board having leads. 10. A circuit board laminated on the surface of a metal plate, lead pads arranged along the side edges on the surface of the circuit board, and a length of the circuit board substantially equal to the width of the circuit board. A lead holder composed of a prismatic main body, and a pair of legs provided in a U shape at both ends of the main body, the lead holder being made of an insulator in which through holes vertically penetrating the main body are arranged. A pin-shaped input / output lead that is fixed to the lead holder by an adhesive filled in the through hole in a state of penetrating the through hole, and a joining surface at the tip abuts on the lead pad and is soldered. The lead holder is mounted so that the legs are seated on both ends of the circuit board so as to bridge the circuit board, and the input / output leads and the lead holder are bonded and fixed to each other. The softening point of the adhesive is Printed circuit board, characterized in that less than the solder reflow temperature for bonding the lead.