JP2015170633A - Manufacturing method of composite wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a composite wiring board having high production efficiency.SOLUTION: By cooling a metal frame 30G after disposing a printed wiring board 10 in an opening 30 in a state where the metal frame 30G is heated to a heating temperature at which the printed wiring board 10 becomes disposable in the thermally expanded opening 30, a side wall of the printed wiring board 10 and a side wall of the opening 30 of the metal frame 30G are joined. Therefore, since steps of filling and curing of an adhesive agent become unnecessary, production efficiency is enhanced and joining of the printed wiring boards 10 to the metal frame 30G at a low price becomes possible.

Description

The present invention relates to a method for manufacturing a composite wiring board in which a wiring board is fixed using a metal frame.

When mounting electronic components on a wiring board, or other processing, etc., considering the work efficiency, it is generally not a single wiring board but a composite in which the same wiring board is housed in a single wiring board housing kit. The above processing and the like are performed collectively on the wiring board. Patent Document 1 discloses a multi-piece wiring board accommodation kit including a plurality of piece wiring boards and a frame having an accommodation hole for accommodating the piece wiring boards.

JP 2011-23657 A

However, in the multi-piece wiring board housing kit of Patent Document 1, an adhesive is injected and bonded between the piece wiring board and the housing hole of the frame at the connection location, and an adhesive that bonds different materials is used. This is necessary, and a process for filling and curing the adhesive is required separately, so that the production efficiency is deteriorated. Furthermore, since the wiring boards are individually fixed in the receiving holes, the positional deviation between the wiring boards is increased, and a decrease in yield in the subsequent process is expected.

An object of the present invention is to provide a method of manufacturing a composite wiring board with high production efficiency.

The method for manufacturing a composite wiring board of the present invention comprises preparing a wiring board,
Providing a metal frame having an opening and having a larger coefficient of thermal expansion in the surface direction than the wiring board;
Placing the wiring board in the opening in a state where the metal frame is heated to a heating temperature at which the wiring board can be placed in the thermally expanded opening;
It is a technical feature that includes cooling the metal frame to join the side wall of the wiring board and the side wall of the opening of the metal frame.

In the method for manufacturing a composite wiring board of the present invention, after the wiring board is disposed in the opening in a state where the metal frame is heated to a heating temperature (for example, 120 ° C.) at which the wiring board can be disposed in the thermally expanded opening. By cooling the metal frame, the side wall of the wiring board and the side wall of the opening of the metal frame are joined. This eliminates the need for an adhesive filling / curing step and reduces the number of processing steps as compared with a bonding method using an adhesive, thereby increasing the production efficiency and allowing the wiring board to be bonded to the metal frame at a low cost. Moreover, since a wiring board should just be arrange | positioned in the thermally expanded opening, the jig | tool for joining can be simplified.

The top view of the printed wiring board for multi-piece taking. The perspective view of the printed wiring board cut out to the piece. The perspective view of the printed wiring board processed with a laser. The top view of the state by which the printed wiring board was joined to the metal frame. The top view of the state which has arrange | positioned the printed wiring board in the opening of the metal frame at the time of thermal expansion for joining. The graph which shows the relationship between heating temperature and the elongation of the principal surface direction at the time of a heating as a reference example. The partial cross section figure of a composite wiring board. The top view of the printed wiring board removed from the composite wiring board. Sectional drawing of the printed wiring board of 1st Embodiment. Sectional drawing of the printed wiring board of 1st Embodiment with which the electronic component was mounted.

[First embodiment]
In the composite wiring board 100 of the present embodiment, in order to prevent warping of the printed wiring board 10 during reflowing for mounting electronic components, a plurality of printed wiring boards 10 that perform reflowing are fixed using a metal frame. It is composed.

FIG. 9 is a cross-sectional view of the printed wiring board 10 according to the first embodiment before mounting electronic components.
In the printed wiring board 10, interlayer insulating layers 50A, 50C, 50E, 50G, and 50I are laminated on the upper surface (first surface) F side of the core insulating layer 50M disposed in the center, and the lower surface (second surface) S side. Interlayer insulating layers 50B, 50D, 50F, 50H, and 50J are laminated. The conductor circuit 58Ma on the first surface F and the conductor circuit 58Mb on the second surface S of the core insulating layer 50M are connected via a via conductor 60M. The core material is disposed in the core insulating layer 50M, and the core material is similarly disposed in the interlayer insulating layers 50A, 50C, 50E, 50G, and 50I and the interlayer insulating layers 50B, 50D, 50F, 50H, and 50J.

In the interlayer insulating layer 50A stacked on the first surface F side of the core insulating layer 50M, a via conductor 60A for connecting the conductor circuit 58A on the interlayer insulating layer 50A to the conductor circuit 58Ma of the core insulating layer 50M is provided. Is formed. Via conductor 60C for connecting conductor circuit 58C on interlayer insulating layer 50C to conductor circuit 58A on interlayer insulating layer 50A is formed in interlayer insulating layer 50C laminated on interlayer insulating layer 50A. Yes. Via conductor 60E for connecting conductor circuit 58E on interlayer insulating layer 50E to conductor circuit 58C on interlayer insulating layer 50C is formed in interlayer insulating layer 50E laminated on interlayer insulating layer 50C. Yes. A via conductor 60G for connecting the conductor circuit 58G on the interlayer insulating layer 50G to the conductor circuit 58E on the interlayer insulating layer 50E is formed in the interlayer insulating layer 50G laminated on the interlayer insulating layer 50E. Yes. Via conductor 60I for connecting conductor circuit 58I on interlayer insulating layer 50I to conductor circuit 58G on interlayer insulating layer 50G is formed in interlayer insulating layer 50I stacked on interlayer insulating layer 50G. Yes. A solder resist layer 62F is formed on the interlayer insulating layer 50I, and a conductor circuit 58I exposed from the opening 64F of the solder resist layer constitutes a pad 66F.

In the interlayer insulating layer 50B stacked on the second surface S side of the core insulating layer 50M, a via conductor 60B for connecting the conductor circuit 58B on the interlayer insulating layer 50B to the conductor circuit 58Mb of the core insulating layer 50M is provided. Is formed. A via conductor 60D for connecting the conductor circuit 58D on the interlayer insulation layer 50D to the conductor circuit 58B on the interlayer insulation layer 50B is formed on the interlayer insulation layer 50D laminated on the interlayer insulation layer 50B. Yes. Via conductor 60F for connecting conductor circuit 58F on interlayer insulating layer 50F to conductor circuit 58D on interlayer insulating layer 50D is formed in interlayer insulating layer 50F stacked on interlayer insulating layer 50D. Yes. Via conductor 60H for connecting conductor circuit 58H on interlayer insulating layer 50H to conductor circuit 58F on interlayer insulating layer 50F is formed in interlayer insulating layer 50H laminated on interlayer insulating layer 50F. Yes. Via conductor 60J for connecting conductor circuit 58J on interlayer insulating layer 50J to conductor circuit 58H on interlayer insulating layer 50H is formed in interlayer insulating layer 50J laminated on interlayer insulating layer 50H. Yes. A solder resist layer 62S is formed on the interlayer insulating layer 50J, and the conductor circuit 58J exposed from the opening 64S of the solder resist layer constitutes a pad 66S. Through holes 52 penetrating through the interlayer insulating layers 50I, 50G, 50E, 50C, 50A, 50M, 50B, 50D, 50F, 50H, and 50J are formed.

FIG. 10 is a cross-sectional view of the printed wiring board 10 on which the electronic component 11 is mounted.
The electronic component 11 is mounted on the first surface F side of the printed wiring board 10 via solder 68 provided on the pad 66F. The electronic component 11 is mounted on the second surface S side of the printed wiring board 10 via the solder 68 provided on the pad 66S.

FIG. 1 is a plan view of a multi-piece printed wiring board 10G in which 8 × 4 printed wiring boards 10 are manufactured, and FIG. 2 is a perspective view of the printed wiring board 10 cut into individual pieces. FIG. 9 shows a part of the X1-X1 cross section in FIG.
As shown in FIG. 1, a plurality of printed wiring boards 10 are manufactured inside a frame portion 18 on the outer periphery of the multi-piece printed wiring board 10G. As shown in FIG. 2, the printed wiring board 10 is formed so that two support pieces 12 </ b> V are opposed to the longitudinal side wall 14 </ b> V of one side of the rectangular main body 20 with the main body 20 interposed therebetween. Two support pieces 12H are formed on the side wall 14H on one side so as to be opposed to each other with the main body 20 interposed therebetween. The support piece 12V and the support piece 12H have the same shape and are composed of a rectangular base portion (bridge portion) 12b and a trapezoidal portion 12a whose width widens toward the tip side.

In the first embodiment, when the printed wiring board 10 is cut out from the multiple printed wiring board 10G, as shown in FIG. 3A, the printed wiring board 10 is cut with a laser along the outer shape of the printed wiring board 10, Cut into individual pieces as shown in FIG.

4A is a plan view showing a state in which the metal frame 30G is thermally expanded for joining, and FIG. 4B shows a state in which the printed wiring board 10 is joined to the metal frame 30G. It is a top view. FIG. 5 is a plan view showing a state in which the printed wiring board 10 is disposed in the opening 30 of the metal frame 30G at the time of thermal expansion for bonding.
In the present embodiment, the composite wiring board 100 includes a metal frame 30 </ b> G for joining the four printed wiring boards 10. The metal frame 30G is a frame having a larger coefficient of thermal expansion in the principal surface direction (the direction along the first surface F and the second surface S) than the printed wiring board 10, and for example, an aluminum frame is employed. . The thermal expansion coefficient in the main surface direction of the aluminum metal frame 30G is 23 ppm / ° C., the thermal expansion coefficient in the main surface direction of the resin printed wiring board 10 is 16 ppm / ° C., and the thermal expansion coefficient of the metal frame 30G is printed. It is larger than the thermal expansion coefficient of the wiring board 10. By adjusting the thickness of the metal frame 30G to be thinner than that of the printed wiring board 10, it is adjusted so as to suppress the warpage of the printed wiring board 10 due to the difference in thermal expansion coefficient. Although aluminum is used as the material of the metal frame 30G, copper, stainless steel, or the like can be used as long as it has a coefficient of thermal expansion greater than that of the printed wiring board 10.

As shown in FIG. 4A, the metal frame 30G is provided with four accommodating openings 30 for accommodating the printed wiring board 10, and positioning holes 38 are formed at the four corners. A vertical wall 34V corresponding to the longitudinal side wall 14V of the printed wiring board 10 and a horizontal wall 34H corresponding to the short side wall 14H of the printed wiring board 10 are formed in the accommodating opening 30. The vertical wall 34V includes Four slits 32V corresponding to the four support pieces 12V of the printed wiring board 10 are formed, and four slits 32H corresponding to the four support pieces 12H of the printed wiring board 10 are formed on the horizontal wall 34H. Yes. The vertical wall 34V is formed so that a predetermined clearance is interposed between the longitudinal side wall 14V joined to the slit 32V by the support piece 12V, and the horizontal wall 34H is joined to the slit 32H by the support piece 12H. It is formed so that the same degree of clearance is interposed between the short side wall 14H.

As shown in FIG. 5, the slit 32V and the slit 32H have the same shape, and with respect to the support pieces 12V and 12H of the printed wiring board 10, a base 32b corresponding to the base 12b and a trapezoid 32a corresponding to the trapezoid 12a. Consists of. In the slits 32V and 32H, the base 32b and the trapezoidal portion 32a expand in the main surface direction from the base 12b and the trapezoidal portion 12a together with the thermal expansion of the opening 30 during the thermal expansion for bonding shown in FIG. It is formed to be smaller than 12a.

At the time of joining the metal frame 30G and each printed wiring board 10, the metal frame 30G is heated to a heating temperature at which the printed wiring board 10 can be disposed in the thermally expanded opening 30 (hereinafter, referred to as a joining heating temperature). Then, as shown in FIG. 5, the printed wiring boards 10 are arranged in the openings 30 so that the support pieces 12 </ b> V and 12 </ b> H corresponding to the thermally expanded slits 32 </ b> V and 32 </ b> H are positioned. Thereafter, the contracted slits 32V and 32H and the support pieces 12V and 12H are joined by cooling the metal frame 30G to room temperature. As a result, as shown in FIG. 4B, each printed wiring board 10 is accommodated and fixed in the accommodating opening 30, and each printed wiring board 10 is joined to the metal frame 30G for reflow. The plate 100 is completed. In addition, as a heating means for heating the metal frame 30G, for example, a known heating means such as a hot plate can be employed. Further, as a cooling means for cooling the metal frame 30G, not only air cooling but also known cooling means such as water cooling can be employed.

FIG. 6 is a graph showing the relationship between the heating temperature ΔT (actual temperature−initial temperature: ° C.) and the elongation in the main surface direction during heating for a rectangular metal frame formed with a side of 102 mm as a reference example. It is.
As can be seen from FIG. 6, when the heating temperature exceeds 120 ° C., the difference between the elongation in the main surface direction of the metal frame and the elongation in the main surface direction of the resin substrate corresponding to the printed wiring board 10 increases. For this reason, the said heating temperature for joining is at least 120 degreeC or more, Comprising: Since joining force is not insufficient at the time of reflow, it sets so that the temperature at the time of reflow may be exceeded. In this embodiment, for example, assuming that the solder reflow temperature is 210 ° C., the bonding heating temperature is set to 240 ° C.

In the composite wiring board 100 of the first embodiment, the printed wiring board 10 is placed in the opening 30 in a state in which the metal frame 30G is heated to a bonding heating temperature at which the printed wiring board 10 can be disposed in the thermally expanded opening 30. After the arrangement, the metal frame 30G is cooled to join the side wall of the printed wiring board 10 and the side wall of the opening 30 of the metal frame 30G. This eliminates the need for an adhesive filling / curing step and reduces the number of processing steps relative to the bonding method using an adhesive, thereby increasing the production efficiency and allowing the printed wiring board 10 to be bonded to the metal frame 30G at a low cost. . Moreover, since the printed wiring board 10 should just be arrange | positioned in the opening 30 thermally expanded, the jig | tool for joining can be simplified. In addition, you may use an adhesive agent together in a joining location. In this case, the joint strength between the printed wiring board 10 and the metal frame 30G can be further improved by using the adhesive together.

FIG. 7 shows a part of the X2-X2 cross section of the printed wiring board 10 of FIG.
The metal frame 30G has a thickness t1: 750 μm. The printed wiring board 10 has a thickness t2 of 780 μm. That is, the thickness of the metal frame 30G is thinner than that of the printed wiring board 10. Further, as shown in FIG. 7, the printed wiring board 10 is joined to the metal frame 30G so that the center plane C2 in the thickness direction coincides with the center plane C1 in the thickness direction of the metal frame 30G. For this reason, the metal frame 30G is recessed from the first surface F of the printed wiring board 10, and the metal frame 30G is recessed from the second surface S of the printed wiring board 10. Thereby, the metal frame 30G does not interfere when the electronic components of the printed wiring board 10 are mounted.

As described above, in a state where each printed wiring board 10 is bonded to the metal frame 30G, solder printing is performed, the electronic component 11 or the like is placed, and the electronic component 11 or the like is mounted in a reflow furnace. The slits 32V and 32H of the metal frame 30G are slightly smaller than the support pieces 12V and 12H of the printed wiring board 10 disposed in the opening 30 that has been thermally expanded at a temperature exceeding the temperature during reflow (heating temperature during mounting). Therefore, the printed wiring board 10 is not detached from the metal frame 30G due to heating during reflow.

FIG. 8 is a plan view showing a state in which the printed wiring board 10 is removed from the composite wiring board 100.
After mounting the electronic parts, as shown in FIG. 8, the rectangular main body 20 is cut off from the support pieces 12H and 12V of the printed wiring board 10 and supported by the slits 32H and 32V of the opening 30 for accommodating the metal frame 30G. The main body portion 20 of the printed wiring board 10 is separated with the pieces 12H and 12V remaining.

The printed wiring board 10 of the first modified example of the first embodiment is configured as shown in FIG. 9, the core material is disposed in the core insulating layer 50M, the interlayer insulating layers 50A, 50C, 50E, 50G, 50I, the interlayer insulating No core material is disposed on the layers 50B, 50D, 50F, 50H, and 50J. For this reason, although the printed wiring board 10 is likely to be warped, the metal wiring 30G does not warp the printed wiring board 10 even during reflow.

The present invention is not limited to the above-described embodiment. For example, the present invention may be embodied as follows, and other detailed configurations may be appropriately changed within the scope of the gist of the present invention. It is.
(1) In the above embodiment, the metal frame 30G is not limited to the four openings 30, and a plurality of openings 30 can be formed according to the number of printed wiring boards 10 to be joined.

(2) In the above embodiment, it is preferable that the frame portion made of the metal frame 30G has higher rigidity than the piece portion made of the printed wiring board 10 at the solder reflow temperature.

10 Printed wiring board 12V, 12H Support piece 30G Metal frame 30 Opening 32V, 32H Slit 100 Composite wiring board

Claims (4)

Preparing a wiring board;
Providing a metal frame having an opening and having a larger coefficient of thermal expansion in the surface direction than the wiring board;
Placing the wiring board in the opening in a state where the metal frame is heated to a heating temperature at which the wiring board can be placed in the thermally expanded opening;
A method of manufacturing a composite wiring board, comprising: cooling the metal frame to join the side wall of the wiring board and the side wall of the opening of the metal frame. It is a manufacturing method of the composite wiring board according to claim 1,
Furthermore, mounting the component on the surface of the wiring board in a state where the wiring board and the metal frame are joined, the heating temperature is set higher than the heating temperature at the time of mounting. A method for manufacturing a composite wiring board according to claim 1 or 2,
The wiring board is arranged such that the surface of the metal frame does not protrude from the surface of the wiring board and the back surface of the metal frame does not protrude from the back surface of the wiring board. A method of manufacturing a composite wiring board according to claim 3,
The wiring board is arranged so that a center line in the thickness direction of the wiring board and a center line in the thickness direction of the metal frame coincide with each other.

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