JP7390800B2 - Printed circuit board manufacturing method - Google Patents

Description

The present invention relates to a method of manufacturing a printed circuit board .

In electronic devices, a printed circuit board with electronic components mounted thereon is housed in a housing. One of the mounting structures for printed circuit boards is a mounting structure in which a sub printed circuit board (sub board) is mounted almost perpendicularly to a main printed circuit board (main board). An example of a patent document disclosing such a three-dimensional printed circuit board is, for example, Patent Document 1.

The main board is provided with a main board electrode and a slit into which the sub board is inserted. The main substrate electrode is arranged around the slit. The sub-board is provided with a sub-board electrode electrically connected to the main board electrode. The sub-substrate electrode is arranged at the end of the sub-substrate. The sub-board is inserted into the slit in such a manner that the end of the sub-board protrudes from the slit of the main board. Thereafter, the corresponding sub-board electrodes and main board electrodes are joined by solder.

Japanese Patent Application Publication No. 2008-198814

With a printed circuit board using the conventional mounting structure, when inserting the sub-board into the slit of the main board, the sub-board electrode provided at the end of the sub-board rubs against the wall of the slit, causing damage to the sub-board electrode. may be received. For this reason, when the sub-board electrode and the main board electrode are joined by soldering, it is assumed that the soldering is not performed well, and the reliability of the soldered joint is adversely affected.

The present invention has been made to solve the above problems, and its purpose is to provide a method for manufacturing a printed circuit board that can improve the reliability of the joint.

The method for manufacturing a printed circuit board according to the present invention includes the following steps. A slit forming region in which a slit extending in a first direction is formed is defined, and a first conductor extending in a second direction intersecting the first direction is arranged so as to cross the slit forming region. Prepare the board. A slit penetrating the first substrate is formed in the slit formation region to divide the first conductor into two, and the divided first conductor is formed as a first electrode. A second conductor extending in a third direction and a covering portion extending in a strip shape in a fourth direction intersecting the third direction and covering the second conductor in two are disposed, and a fourth conductor is disposed. A second substrate sheet is prepared in which a dicing area is defined in such a manner that the second conductor and the covering portion are divided into two. By cutting the dicing area, the second conductor, the covering portion, and the second substrate sheet are divided into two and separated as two second substrates. One or more first electronic components are mounted on the first substrate. One or more second electronic components are mounted on the second substrate. The second substrate is inserted into the slit of the first substrate. The bonding material is sprayed while the second substrate is inserted into the slit of the first substrate. In the step of separating the second substrate sheet as a second substrate, in each of the two separated second substrates, the bisected second conductor is used as a second electrode, and the covering portion is separated in the second substrate. The second electrode extends in the third direction starting from the side where the second electrode is covered. In the step of inserting the second substrate into the slit of the first substrate, the side of the second substrate where a portion of the second electrode is covered by the covering portion is inserted into the slit of the first substrate. In the step of spraying the bonding material, the first electrode and the second electrode are bonded by the bonding material.

According to the method for manufacturing a printed circuit board according to the present invention, when the second board is inserted into the slit of the first board, a part of the second electrode is covered by the covering part. Thereby, it is possible to manufacture a printed circuit board in which the second electrode is prevented from being damaged and the reliability of bonding by the bonding material is improved.

1 is a perspective view showing a three-dimensional printed circuit board according to Embodiment 1. FIG. FIG. 3 is a plan view showing a main board of the three-dimensional printed circuit board in the same embodiment. FIG. 3 is a plan view showing a sub-board of the three-dimensional printed circuit board in the same embodiment. FIG. 2 is a partial cross-sectional view taken along the cross-sectional line IV-IV shown in FIG. 1 in the same embodiment. FIG. 3 is a plan view showing one step in the method for manufacturing a three-dimensional printed circuit board in the same embodiment. FIG. 7 is a plan view showing another step in the method for manufacturing a three-dimensional printed circuit board in the same embodiment. FIG. 7 is a partial cross-sectional view showing a step performed after the step shown in FIG. 6 in the same embodiment. FIG. 8 is a partial cross-sectional view showing a step performed after the steps shown in FIGS. 5 and 7 in the same embodiment. FIG. 9 is a perspective view showing a step performed after the step shown in FIG. 8 in the same embodiment. FIG. 7 is a plan view showing one step of a method for manufacturing a three-dimensional printed circuit board according to a comparative example. 11 is a partial cross-sectional view showing a step performed after the step shown in FIG. 10. FIG. 12 is a partial cross-sectional view showing a step performed after the step shown in FIG. 11. FIG. 13 is a partial cross-sectional view showing a step performed after the step shown in FIG. 12. FIG. FIG. 3 is a diagram for explaining an example of an effect in the same embodiment. FIG. 7 is a plan view showing a sub-board in a three-dimensional printed circuit board according to a modified example of the same embodiment. FIG. 7 is a partial cross-sectional view of a three-dimensional printed circuit board according to another modification of the same embodiment. FIG. 7 is a partial cross-sectional view showing a three-dimensional printed circuit board according to a second embodiment. FIG. 3 is a plan view showing one step in the method for manufacturing a three-dimensional printed circuit board in the same embodiment. 19 is a partial cross-sectional view showing a step performed after the step shown in FIG. 18 in the same embodiment. FIG. FIG. 20 is a partial cross-sectional view showing a step performed after the step shown in FIG. 19 in the same embodiment. FIG. 7 is a partial cross-sectional view for explaining a problem with a three-dimensional printed circuit board according to a comparative example. FIG. 3 is a partial cross-sectional view for explaining the effects of the three-dimensional printed circuit board in the same embodiment. FIG. 7 is a perspective view showing a three-dimensional printed circuit board according to a third embodiment. FIG. 3 is a plan view showing one step in the method for manufacturing a three-dimensional printed circuit board in the same embodiment. 25 is a partially enlarged plan view of the main board in the process shown in FIG. 24 in the same embodiment. FIG. FIG. 26 is a partially enlarged plan view of the main board in a step performed after the step shown in FIG. 25 in the same embodiment. FIG. 27 is a partially enlarged plan view of the main board in a step performed after the step shown in FIG. 26 in the same embodiment. FIG. 28 is a partially enlarged plan view of the main board in a step performed after the step shown in FIG. 27 in the same embodiment. FIG. 29 is a perspective view showing a step performed after the step shown in FIG. 28 in the same embodiment. FIG. 2 is a first partially enlarged plan view of the three-dimensional printed circuit board for explaining the effects in the same embodiment. FIG. 7 is a second partially enlarged plan view of the three-dimensional printed circuit board for explaining the effects in the same embodiment.

Embodiment 1.
A three-dimensional printed circuit board and the like according to the first embodiment will be explained. Note that for convenience of explanation, XYZ coordinate axes are used. As shown in FIG. 1, the three-dimensional printed circuit board 1 includes a main board 3 as a first board and a sub board 21 as a second board. The main board 3 is arranged parallel to the XY plane, and the sub board 21 is arranged parallel to the ZX plane.

For each of the main board 3 and sub-board 21, a glass cloth/glass non-woven fabric composite epoxy resin copper-clad laminate (CEM-3: Composite Epoxy Material-3), which is a laminated board using pre-greg, is applied as a printed circuit board. has been done. Pregreg is a sheet-like reinforced plastic molding material made by impregnating a fibrous reinforcing base material such as glass cloth or carbon fiber with a thermosetting resin such as an epoxy resin to bring it into a semi-cured state.

One or more first electronic components 61 are mounted on the main board 3 by soldering. The first electronic component 61 includes, for example, an IC (Integrated Circuit), a capacitor, a resistor, a coil, and the like. On the main board 3, the first electronic component 61 and the like constitute, for example, an inverter circuit. An inverter circuit is a power supply circuit that generates alternating current with different frequencies from direct current or alternating current.

One or more second electronic components 63 are mounted on the sub-board 21 by soldering. The second electronic component 63 includes, for example, an IC, a capacitor, a resistor, a coil, and the like. In the sub-board 21, the second electronic component 63 and the like constitute, for example, a control circuit that controls the operation of the main board 3.

As shown in FIG. 2, the main board 3 has a main surface 3a and a main surface 3b that face each other. A slit 5 extending in the X direction as the first direction is provided in the main board 3 so as to penetrate through the main board 3. A plurality of main substrate electrodes 7 as first electrodes are formed on the main surface 3b of the main substrate 3. The main substrate electrode 7 is formed to extend from the slit 5 in the Y direction, which is a second direction intersecting the X direction. In the slit 5, the end face of the main substrate electrode 7 is exposed.

As shown in FIG. 3, the sub-board 21 includes a main body portion 21a and an insertion portion 21b. The insertion portion 21b is inserted into the slit 5 of the main board 3. The insertion portion 21b has opposing main insertion surfaces 21ba and 21bb. A plurality of sub-substrate electrodes 23 as second electrodes are formed on each of the main insertion surfaces 21ba and 21bb. The sub-board electrode 23 is formed to extend from the tip of the main insertion surfaces 21ba and 21bb in the Z direction (main body portion 21a) as the third direction.

The insertion portion 21b is formed with a solder resist processing portion 25 as a covering portion that covers the portion of the sub-substrate electrode 23 located on the tip end side of each of the insertion main surfaces 21ba and 21bb. The solder resist processing section 25 starts from the tip of the main insertion surfaces 21ba and 21bb and extends in a direction away from the tip (Z direction) (see FIG. 4). As will be described later, the solder resist processing section 25 is formed by, for example, a photolithography method.

As shown in FIG. 4, in the three-dimensional printed circuit board 1, the insertion portion 21b of the sub-board 21 is inserted into the slit 5 of the main board 3, and the corresponding main board electrode 7 and sub-board electrode 23 are connected to each other. are bonded using solder 31 as a bonding material. The solder 31 joins the portion of the sub-board electrode 23 that is not covered by the solder resist processing section 25 and the main board electrode 7 . As a result, the main board 3 and the sub-board 21 are physically and electrically connected, and a single printed circuit board is configured in which the control circuit of the sub-board 21 controls the inverter circuit of the main board 3. The three-dimensional printed circuit board 1 according to the first embodiment is configured as described above.

Next, an example of a method for manufacturing the three-dimensional printed circuit board 1 described above will be described. As shown in FIG. 5, the main board 3 is prepared. The main substrate 3 is formed, for example, by processing a base material (not shown) into an external shape using a cutting blade of a router. A slit forming area (see the two-dot chain line) is defined in the main substrate 3 in which a slit extending in the X direction as the first direction is formed. First conductors 6 extending in the Y direction, which is the second direction, are arranged so as to cross the slit forming region. The first conductor 6 becomes the main substrate electrode 7. Next, the first conductor 6 is divided into two by forming, for example, a slit 5 that penetrates the main substrate 3 in the slit formation region using a cutting blade (not shown). The first conductor 6 divided into two becomes the main substrate electrode 7. In this way, the main board 3 shown in FIG. 2 is obtained.

Next, as shown in FIG. 6, a sub-substrate sheet 27 that will become the sub-substrate 21 as a second substrate is prepared. A second conductor 22 serving as a sub-substrate electrode 23 is formed on the sub-substrate sheet 27 . The second conductors 22 extend in the Z direction, which is the third direction, and are spaced apart from each other in the X direction, which is the fourth direction. The sub-substrate sheet 27 is obtained by processing a base material (not shown) on which the second conductor 22 is previously formed using, for example, a cutting blade of a router.

Next, resist ink (not shown) is applied so as to cover the sub-substrate sheet 27. Next, the resist ink is semi-cured and a desired photolithography process is performed. As a result, the solder resist treated portion 25 as a covering portion is formed so as to extend in a band shape in the X direction in such a manner that the second conductor 22 is divided into two. Furthermore, a dicing region 28 extending in the X direction is defined in such a manner as to divide the second conductor 22 and the solder resist processing section 25 into two.

Next, as shown in FIGS. 6 and 7, by cutting the dicing area 28 with the cutting blade 51, the second conductor 22, the solder resist processing section 25, and the sub-substrate sheet 27 are divided into two, and the two sub-substrates are separated. Separate as 21. On one of the two sub-substrates 21 , one portion of the second conductor 22 divided into two is formed as a plurality of sub-substrate electrodes 23 . On the other sub-substrate 21 of the two sub-substrates 21, the other portion of the second conductor 22 divided into two is formed as a plurality of sub-substrate electrodes 23. Next, the first electronic component 61 is mounted on the main board 3 by, for example, soldering. Further, the second electronic component 63 is mounted on the sub-board 21 by, for example, soldering (see FIG. 1).

Next, as shown in FIG. 8, the insertion portion 21b of the sub-board 21 is inserted into the slit 5 formed in the main board 3. At this time, a solder resist processing part 25 is formed on the tip side of the insertion part 21b so as to cover the sub-board electrode 23, thereby preventing the sub-board electrode 23 from directly contacting the slit 5. be done.

Next, as shown in FIG. 9, with the insertion portion 21b of the sub-board 21 inserted into the slit 5 of the main board 3, the main board is conveyed in the X direction by a conveyor (not shown), for example. Electrode 7 and sub-substrate electrode 23 are immersed in jet 53 of molten solder. As a result, the three-dimensional printed circuit board 1 shown in FIGS. 1 and 4 is manufactured.

In the three-dimensional printed circuit board 1 described above, the solder resist processing section 25 is formed to cover the sub-board electrode 23. Thereby, when inserting the insertion portion 21b of the sub-board 21 into the slit 5 of the main board 3, it is possible to prevent the sub-board electrode 23 from rubbing against the slit 5. This will be explained in comparison with a three-dimensional printed circuit board according to a comparative example.

As shown in FIG. 10, in the three-dimensional printed circuit board 101 according to the comparative example, first, a sub-board sheet 127 that becomes the sub-board 121 is prepared. The second conductors 122 are arranged on the sub-substrate sheet 127 so as to be spaced apart from each other in the X direction and extend in the Y direction. No solder resist processing portion is formed on the sub-substrate sheet 127.

Next, as shown in FIGS. 10 and 11, the second conductor 122 and the sub-substrate sheet 127 are divided into two by cutting the dicing region 128 with the cutting blade 51, and the two sub-substrates 121 are separated. One of the second conductors divided into two is formed as a plurality of sub-substrate electrodes 123 on one sub-substrate 121 . The other of the two divided second conductors is formed as a plurality of sub-substrate electrodes 123 on the other sub-substrate 121 .

Next, as shown in FIG. 12, the insertion portion 121b of the sub-board 121 is inserted into the slit 105 formed in the main board 103. Thereafter, the sub-board 121 is inserted into the slit 105 of the main board 103 and exposed to a jet of molten solder. In this way, as shown in FIG. 13, a three-dimensional printed circuit board 101 is manufactured in which the corresponding main board electrodes 107 and sub-board electrodes 123 are joined by solder 131.

In the three-dimensional printed circuit board 101 according to the comparative example, when the insertion part 121b of the sub-board 121 is inserted into the slit 105, the sub-board electrode 123 is exposed in the insertion part 121b. Therefore, it is assumed that the exposed sub-substrate electrode 123 comes into direct contact with the slit 105, and the sub-substrate electrode 123 is damaged (see inside the circle W1 in FIG. 12).

If the sub-board electrode 123 is immersed in a jet of molten solder in a damaged state, the main board electrode 107 and the sub-board electrode 123 may not be properly bonded. As a result, the reliability of the joint may be reduced.

In contrast to the three-dimensional printed circuit board according to the comparative example, in the three-dimensional printed circuit board 1 described above, as shown in FIG. A solder resist processing portion 25 is formed to cover a portion of the sub-substrate electrode 23 located on the tip side.

Therefore, as shown in FIG. 8, when inserting the insertion portion 21b of the sub-board 21 into the slit 5 of the main board 3, the sub-board electrode 23 is prevented from rubbing against the slit 5, and the sub-board electrode 23 is prevented from rubbing against the slit 5. It is possible to prevent the electrode 23 from being damaged. Thereby, the corresponding main board electrode 7 and sub-board electrode 23 can be bonded well by being immersed in the jet of molten solder.

Furthermore, by adjusting the thickness of the solder resist treated portion 25 (for example, about 40 to 60 μm), the molten solder can be supported from below by the solder resist treated portion 25 when immersed in a jet of molten solder. become. Thereby, it is possible to prevent the solder 31 from falling off from the sub-board electrode 23 and from creating a portion where the solder 31 is not bonded.

Furthermore, in contrast to the three-dimensional printed circuit board according to the comparative example, in the three-dimensional printed circuit board 1 described above, the solder resist treatment portion 25 is formed, so that the sub-board electrode 23 is not exposed to the jet of molten solder. This allows the solder 31 to be bonded for a longer period of time, thereby improving the reliability of the joints formed by the solder 31. This will be explained.

In the step of immersing in the molten solder jet 53, the main board electrode 7 and the sub-board electrode 23 are sequentially dipped while being conveyed by a conveyor of a solder flow tank that stores molten solder. At this time, the amount of solder (fillet volume) that joins the corresponding main board electrode 7 and sub-board electrode 23 is determined by the amount of solder that adheres to the main board electrode 7 and sub-board electrode 23. The amount of solder is determined by the relationship between the surface tension of the solder on the main substrate electrode 7 and the sub-substrate electrode 23 and gravity.

If the temperatures of the main board electrode 7 and the sub-board electrode 23 are high when immersed in molten solder, the temperatures of the molten solder on the main board electrode 7 and the sub-board electrode 23 will also become high. . In this case, the viscosity of the molten solder decreases, and the rate at which the molten solder spreads while wetting each of the main substrate electrode 7 and the sub-substrate electrode 23 due to capillarity increases. Therefore, the fillet volume of the solder 31 that joins the corresponding main substrate electrode 7 and sub-substrate electrode 23 can be increased.

On the other hand, when the temperatures of the main board electrode 7 and the sub-board electrode 23 are low, the temperatures of the molten solder on the main board electrode 7 and the sub-board electrode 23 are also low. In this case, the viscosity of the molten solder increases, and the speed at which the molten solder spreads while wetting each of the main board electrode 7 and the sub-board electrode 23 due to capillary action becomes slow. Therefore, the fillet volume of the solder 31 that joins the corresponding main substrate electrode 7 and sub-substrate electrode 23 becomes small.

After the solder 31 has been bonded, the three-dimensional printed circuit board 1 is assembled into a product. When a product is in operation, depending on the usage environment, the three-dimensional printed circuit board may be exposed to a high temperature environment or a low temperature environment (temperature cycling). Therefore, stress caused by the difference in thermal expansion coefficients between the main board 3 and the sub-board electrode 21 repeatedly acts on the portion of the solder 31 that joins the main board electrode 7 and the sub-board electrode 23. As a result, thermal strain may occur in the solder 31, which may eventually lead to fatigue failure.

At this time, when the fillet volume of the solder 31 is large, the mechanical strength is stronger than when the fillet volume of the solder 31 is small. As a result, when the fillet volume of the solder 31 is large, the time required for the solder 31 portion to break is longer than when the fillet volume of the solder 31 is small.

Here, the following conditions are applied to the three-dimensional printed circuit board 1 according to the embodiment (example) and the three-dimensional printed circuit board according to the comparative example (comparative example) shown in FIG. Suppose. The area of the exposed sub-substrate electrode 23 (length L x depth) is the same as the area of the exposed sub-substrate electrode 123 (length L x depth). The speed at which the three-dimensional printed circuit board 1 is transported is the same as the speed at which the three-dimensional printed circuit board according to the comparative example is transported. The molten solder jet conditions for the three-dimensional printed circuit board 1 and the molten solder jet conditions for the three-dimensional printed circuit board according to the comparative example are set to be the same jet conditions.

FIG. 14 shows how a three-dimensional printed circuit board is immersed in a jet of molten solder in the order of state A, state B, state C, and state D in chronological order. As shown in FIG. 14, first, in the comparative example, from state A to state B, the three-dimensional printed circuit board is immersed in a jet of molten solder, and the heat of the molten solder is conducted to the printed circuit board. After state C, the three-dimensional printed circuit board is not immersed in the jet of molten solder, and the heat of the molten solder is not conducted to the printed circuit board.

On the other hand, in the embodiment, from state A to state C, the three-dimensional printed circuit board is immersed in a jet of molten solder, and the heat of the molten solder is conducted to the printed circuit board. As a result, more heat from the molten solder is conducted to the three-dimensional printed circuit board than in the three-dimensional printed circuit board according to the comparative example.

This increases the temperature of each of the main board electrode 7 and the sub-board electrode 23, and as described above, increases the fillet volume of the solder 31 that joins the corresponding main board electrode 7 and sub-board electrode 23. Can be done. As a result, the mechanical strength of the joint between the main board electrode 7 and the sub-board electrode 23 can be increased, and the reliability of the joint by the solder 31 can be improved.

(Modified example)
In the three-dimensional printed circuit board 1 described above, as shown in FIG. 4, the solder resist processing portion 25 covering the sub-board electrode 23 is formed in a direction away from the tip of the main insertion surfaces 21ba and 21bb, starting from the tip. The explanation has been given by taking as an example the case where it extends in the Z direction).

As shown in FIG. 15, the solder resist processing section 25 includes, for example, a solder resist processing section further extending in the Z direction so as to cover a portion located between adjacent sub-substrate electrodes 23. Section 25 may also be applied. In this case, when leaving the jet of molten solder, the molten solder is likely to break, and it is possible to prevent the adjacent sub-board electrodes 23 from being joined by solder. That is, soldering defects such as bridging can be reduced.

Further, as shown in FIG. 16, a solder resist processing section 26 may be provided to cover the end surface 21bc of the insertion section 21b. In this case, it is possible to effectively prevent the sub-substrate electrode 23 from being damaged when the sub-substrate 21 is inserted into the slit 5.

Further, as a method for forming the solder resist processing portion 25, in addition to a method of forming by photolithography, a direct imaging method, a screen printing method, or the like may be applied. The direct imaging method is a method of applying resist ink to the entire surface of a substrate and selectively curing it using a laser beam or the like to selectively perform resist processing. The screen printing method is a method in which resist treatment is selectively performed by selectively curing resist ink printed on a substrate through a screen by irradiation with light. Even with solder resist treated portions formed using these methods, the same effects as in the case of resist treated portions formed by photolithography can be obtained.

In the three-dimensional printed circuit board described above, CEM-3 was used as an example of the main board 3 and the sub-board 21 for explanation. As the main substrate 3 and the sub-board 21, for example, a heat-resistant glass cloth base epoxy resin copper-clad laminate (FR-4: Flame retardant-4) may be used. FR-4 is a heat-resistant glass cloth-based epoxy resin copper-clad laminate made of glass fiber cloth impregnated with epoxy resin.

Further, a paper phenol substrate may be used as the main substrate 3 and the sub-substrate 21. A paper phenolic substrate is a substrate formed by impregnating insulating paper with phenolic resin. Furthermore, as the main board 3 and the sub-board 21, a ceramic board or the like formed by simultaneously firing a wiring conductor and a ceramic base material may be used. Even when these substrates are applied, the same effects as in the case of CEM-3 can be obtained.

Further, the main substrate 3 and the sub-substrate 21 may be made of different materials, for example, CEM-3 may be used as the sub-substrate 21 and FR-4 may be used as the main substrate 3. Even when such a substrate is applied, the same effects as in the case of CEM-3 can be obtained.

Embodiment 2.
A three-dimensional printed circuit board and the like according to the second embodiment will be explained. As shown in FIG. 17, in the three-dimensional printed circuit board 1, the sub-board electrode 23 starts from a position separated by a distance D from the tip of the main insertion surface 21ba, 21bb of the insertion part 21b, and starts at a position separated from the tip of the main insertion surface 21ba, 21bb of the insertion part 21b. It extends toward the side (Z direction). The distance D is, for example, about 0.1 mm to 0.5 mm.

The solder resist processing portion 25 is formed to extend in the Z direction starting from the tips of the main insertion surfaces 21ba and 21bb, and to cover the sub-substrate electrode 23 portion. That is, the solder resist processing portion 25 covers the sub-substrate electrode 23 in an overhanging manner upward from the tip side of the main insertion surfaces 21ba and 21bb. The rest of the structure is the same as that of the three-dimensional printed circuit board shown in FIGS. 1 and 4, so the same members are designated by the same reference numerals and the description thereof will not be repeated unless necessary. shall be.

Next, an example of a method for manufacturing the three-dimensional printed circuit board 1 described above will be described. As shown in FIG. 18, a sub-substrate sheet 27 is prepared. The sub-substrate sheet 27 is formed with a first portion 22a of the second conductor and a second portion 22b of the second conductor, each of which becomes the sub-substrate electrode 23. Each of the second conductor first part 22a and the second conductor second part 22b extends in the Z direction as the third direction. The second conductor second portion 22b and the second conductor first portion 22a are spaced apart from each other in the Z direction.

Each of the second conductor first part 22a and the second conductor second part 22b in the region located between the second conductor first part 22a and the second conductor second part 22b is A dicing region 28 is defined in a strip shape at a distance in the direction.

Next, the solder resist processing portion 25 is formed, for example, by photolithography. The solder resist processing section 25 covers a part of each of the second conductor first part 22a and the second conductor second part 22b, and also covers the second conductor second part 22b and the second conductor first part 22a. It is formed to cover the area located between. The strip-shaped solder resist processing section 25 is formed to extend in the X direction.

Next, as shown in FIGS. 18 and 19, by cutting the dicing area 28 with the cutting blade 51 along the A substrate 21 is formed. On one of the two sub-substrates 21 , the second conductor first portion 22 a becomes the sub-substrate electrode 23 . On the other sub-substrate 21 of the two sub-substrates 21, the second conductor second portion 22b becomes the sub-substrate electrode 23. At this time, since the dicing region 28 is separated from each of the second conductor first part 22a and the second conductor second part 22b, cutting waste such as the second conductor first part 22a is not generated. do not have. Next, the first electronic component 61 is mounted on the main board 3 by, for example, soldering. Further, a second electronic component 63 is mounted on the sub-board 21 by, for example, soldering (see, for example, FIG. 1).

Next, as shown in FIG. 20, the insertion portion 21b of the sub-board 21 is inserted into the slit 5 formed in the main board 3. At this time, a solder resist processing part 25 is formed on the tip side of the insertion part 21b so as to cover the sub-board electrode 23, thereby preventing the sub-board electrode 23 from directly contacting the slit 5. be done. Thereafter, the three-dimensional printed circuit board 1 shown in FIG. 17 is manufactured through steps similar to those shown in FIG.

In the three-dimensional printed circuit board 1 described above, the solder resist processing section 25 is formed to cover the sub-board electrode 23. As a result, the corresponding main board electrodes 7 and sub-board electrodes 23 can be bonded well in the same way as described for the three-dimensional printed circuit board 1 described above. Further, it is possible to prevent the occurrence of a portion where no bonding with the solder 31 is performed. Furthermore, the fillet volume of the solder 31 that joins the corresponding main board electrode 7 and sub-board electrode 23 can be increased, and the reliability of the joint by the solder 31 can be improved.

The three-dimensional printed circuit board 1 described above further provides the following effects. First, in the sub-board sheet 27 that becomes the sub-board 21 of the three-dimensional printed circuit board 1, the dicing area 28 is defined apart from each of the first part 22a of the second conductor 22b and the second part 22b of the second conductor. ing. Therefore, when cutting the dicing region 28 with the cutting blade 51, the cutting blade 51 does not come into contact with the first part 22a of the second conductor or the second part 22b of the second conductor. Thereby, it is also possible to prevent solder bonding defects caused by cutting waste from the first portion 22a of the second conductor or the second portion 22b of the second conductor.

Further, when the solder adhering to the main substrate electrode 7 and the sub-substrate electrode 23 solidifies, the sub-substrate electrode 23 can be prevented from peeling off from the sub-substrate 21. This will be explained in comparison with the three-dimensional printed circuit board according to the comparative example described above.

After the three-dimensional printed circuit board 101 is immersed in the jet of molten solder, the solder 131 adhering to the main board electrode 107 and the sub-board electrode 123 will solidify. When the solder 131 solidifies, the solder 131 contracts. Therefore, as shown in FIG. 21, it is assumed that the sub-substrate electrode 123 will peel off from the sub-substrate 121 as the solder 131 shrinks.

In contrast to the three-dimensional printed circuit board 101 according to the comparative example, in the three-dimensional printed circuit board 1 described above, the solder resist processing section 25 is continuous from the main insertion surfaces 21ba and 21bb to a part of the sub-board electrode 23. It is formed to cover. Thereby, as shown in FIG. 22, even if the solder 31 contracts when the solder 31 solidifies, the sub-substrate electrode 23 can be prevented from peeling off from the sub-substrate 21.

Further, in the three-dimensional printed circuit board 1 described above, the sub-board electrode 23 starts from a position separated by a distance D from the tip of the main insertion surfaces 21ba and 21bb of the insertion part 21b, and moves toward the main body part 21a. It has been extended. Therefore, at the tip of the insertion portion 21b, the solder resist processing portion 25 is formed to directly cover the insertion main surfaces 21ba and 21bb.

Therefore, compared to a structure in which the sub-board electrode 23 is formed starting from the tips of the main insertion surfaces 21ba and 21bb and is covered with the solder resist processing part 25, the thickness of the tip of the insertion part 21b of the sub-board 21 is smaller. Become thin. Thereby, even if the width of the slit is narrow, the insertion portion 21b of the sub-board 21 can be easily inserted into the slit 5. As a result, it is possible to contribute to the efficient manufacture of the three-dimensional printed circuit board 1.

(Modified example)
In the three-dimensional printed circuit board 1 described above, a case has been described in which the outer shape of the sub-board sheet 27 is processed by cutting using a router. In addition to this, the sub-substrate sheet 27 may be punched, for example, by applying press processing using a mold.

Embodiment 3.
A three-dimensional printed circuit board and the like according to the third embodiment will be explained. As shown in FIG. 23, in the three-dimensional printed circuit board 1, a sub-board 21 is attached to the slit 5 of the main board 3. A castellation electrode portion 11 is provided in the slit 5 .

The castellation electrode portion 11 is formed so as to retreat from the sub-substrate 21 in the Y direction. The rest of the structure is the same as that of the three-dimensional printed circuit board shown in FIGS. 1 and 4, so the same members are designated by the same reference numerals and the description thereof will not be repeated unless necessary. shall be.

Next, an example of a method for manufacturing the three-dimensional printed circuit board 1 described above will be described. As shown in FIG. 24, the main board 3 is prepared. The main substrate is formed, for example, by processing a base material (not shown) into an external shape using a cutting blade of a router. As shown in FIGS. 24 and 25, a first conductor 6 that becomes the main board electrode 7 is arranged on the main board 3. As shown in FIGS.

Next, oval openings are formed in each portion of the first conductor 6. First, as shown in FIG. 25, a center line CL where the center of the opening is located is defined along the longitudinal direction (X direction) of the area where the slit is to be formed on the main board 3, and the width of the slit is and the length R based on the amount of retreat from the slit.

Next, as shown in FIG. 26, oval openings 9a and 9b are formed in each of the first conductors 6 by sliding the cutting blade 51 of the router along the defined center line CL. be done. Next, as shown in FIG. 27, through-holes 10a and 10b, each of which has an inner wall surface of openings 9a and 9b covered with a conductive layer (not shown), are formed by plating. The through holes 10a and 10b become castellation electrode parts.

Next, as shown in FIG. 28, slits 5 are formed in the main substrate 3 by, for example, press processing using a mold. At this time, it is desirable that the amount of retreat BL from the slit 5 is 0.5 mm or less. In this way, the castellation electrode section 11 is formed. On the other hand, the sub-substrate 21 (see FIG. 23) is formed through steps similar to those shown in FIGS. 6 and 7, for example.

Next, as shown in FIG. 29, the insertion part 21b of the sub-board 21 is inserted into the slit 5 of the main board 3 in which the castellation electrode part 11 is formed. Thereafter, the three-dimensional printed circuit board 1 shown in FIG. 23 is manufactured through steps similar to those shown in FIG.

In the three-dimensional printed circuit board 1 described above, the solder resist processing portion 25 is formed to cover the sub-board electrode 23, so that the corresponding main board electrode 7 and the sub-board electrode 23 are bonded well. be able to. Further, it is possible to prevent the occurrence of a portion where no bonding with the solder 31 is performed.

The three-dimensional printed circuit board 1 described above further provides the following effects. In the three-dimensional printed circuit board 1, a castellation electrode portion 11 is formed in the slit 5. Therefore, as shown in FIG. 29, when inserting the insertion part 21b of the sub-board into the slit 5, the insertion part 21b of the sub-board is inserted into the slit 5 as shown in FIG. In addition, the sub-board 21 hardly contacts the main board electrode 7. Thereby, the corresponding main substrate electrode 7 and sub-substrate electrode 23 can be bonded even better. Furthermore, it is possible to reliably prevent the occurrence of portions where the solder 31 is not bonded.

Furthermore, when immersed in a jet of molten solder, the molten solder flows into the castellation electrode portion 11 retreated from the sub-board 21 by capillary action. Therefore, the fillet volume of the solder that joins the corresponding main substrate electrode 7 and sub-substrate electrode 23 can be further increased. Thereby, the reliability of the joint made by the solder 31 can be further improved.

(Modified example)
In the three-dimensional printed circuit board 1 described above, a case has been described in which the oval openings 9a and 9b are formed in the main board 3 using the cutting blade 51. In addition, the same effect can be obtained by forming the oval openings 9a and 9b in the main substrate 3, for example, by press working with a mold.

Note that the three-dimensional printed circuit boards described in each embodiment can be combined in various ways as necessary.

The embodiment disclosed this time is an example and is not limited thereto. The present invention is defined not by the scope described above, but by the scope of the claims, and is intended to include all changes within the meaning and range equivalent to the scope of the claims.

INDUSTRIAL APPLICATION This invention is effectively utilized for a three-dimensional printed circuit board.

1 printed circuit board, 3 main board, 3a, 3b main surface, 5 slit, 6 first conductor, 7 main board electrode, 9a, 9b opening, 10a, 10b through hole, 11 castellation electrode section, 21 sub board , 21a main body part, 21b insertion part, 21ba, 21bb insertion main surface, 21bc insertion end surface, 22 second conductor, 22a first part of second conductor, 22b second part of second conductor, 23 sub-board electrode, 25 , 26 solder resist processing section, 27 sub-substrate sheet, 28 dicing area, 31 solder, 51 cutting blade, 53 jet solder, 61 first electronic component, 63 second electronic component.

Claims (4)

A slit forming region in which a slit extending in a first direction is formed is defined, and a first conductor extending in a second direction intersecting the first direction is arranged so as to cross the slit forming region. a step of preparing a first substrate;
forming the slit penetrating the first substrate in the slit formation region, dividing the first conductor into two, and forming the divided first conductor as a first electrode;
A second conductor extending in a third direction, and a covering portion extending in a strip shape in a fourth direction intersecting the third direction and covering the second conductor so as to divide the second conductor into two are disposed, and preparing a second substrate sheet that extends in the fourth direction and defines a dicing area in a manner that bisects the second conductor and the covering portion;
dividing the second conductor, the covering portion, and the second substrate sheet into two by cutting the dicing area, and separating them as two second substrates;
mounting one or more first electronic components on the first substrate;
mounting one or more second electronic components on the second substrate;
inserting the second substrate into the slit of the first substrate;
spraying a bonding material while the second substrate is inserted into the slit of the first substrate,
In the step of separating the second substrate sheet as the second substrate, in each of the two separated second substrates, the bisected second conductor is used as a second electrode, and the covering portion is extending in the third direction starting from the separated side of the second substrate and covering a part of the second electrode;
In the step of inserting the second substrate into the slit of the first substrate, the second substrate has a side where a portion of the second electrode is covered by the covering portion is inserted into the slit of the first substrate. inserted,
In the method of manufacturing a printed circuit board, in the step of spraying the bonding material, the first electrode and the second electrode are bonded by the bonding material. In the step of separating the second substrate sheet as the second substrate, in each of the two separated second substrates, the second electrode is connected to the third electrode starting from the separated side of the second substrate. The method of manufacturing a printed circuit board according to claim 1 , wherein the printed circuit board extends in the direction. In the step of preparing the second substrate sheet,
The second conductor is
a first portion of a second conductor extending in the third direction;
a second part of the second conductor extending in the third direction and spaced apart from the first part of the second conductor in the third direction;
The covering portion is arranged to include a portion covering a region between the first portion of the second conductor and the second portion of the second conductor,
The dicing region is configured to separate the first part of the second conductor and the second part of the second conductor in the region between the first part of the second conductor and the second part of the second conductor. is defined in a portion separated by a distance in the third direction,
In the step of separating the second substrate sheet as the second substrate,
Of the two separated second substrates, one of the second substrates includes:
The first part of the second conductor is a first part of a second electrode,
The first portion of the second electrode extends in the third direction from a position spaced apart from the separated side of the second substrate in the third direction,
Of the two separated second substrates, the other second substrate includes:
The second part of the second conductor is a second part of a second electrode,
The printed circuit board according to claim 1 , wherein the second portion of the second electrode extends in the third direction from a position spaced apart in the third direction from the separated side of the second substrate. manufacturing method. The step of forming the slit includes:
forming a first opening and a second opening in the first conductor so as to be separated from each other in the second direction and to penetrate through the first substrate;
forming a conductive film so as to cover side wall surfaces of each of the first opening and the second opening;
By forming the slit in such a manner that a side wall portion of the first opening is left so as to recede from the slit, and a side wall portion of the second opening is left so as to recede from the slit, the slit can be removed from the slit. a step of using a receded side wall portion of the first opening and a side wall portion of the second opening as a castellation electrode portion;
Manufacturing a printed circuit board according to claim 1 , wherein in the step of inserting the second board into the slit of the first board, the second board is inserted into the slit in which the castellation electrode portion is formed. Method.

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