JP4144318B2 - Board connection method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a printed circuit board and the flexible board to board connection methods of joining by alkanes connection.
[0002]
[Prior art]
Conventionally, alkanes are applied to at least one of the printed wiring terminals formed on the surface of the printed circuit board and the copper foil formed on the surface of the flexible circuit board, and the flexible circuit board is heated and pressure-bonded to the printed circuit board. There is a substrate connection method in which a flexible substrate is bonded to the flexible substrate (see, for example, Patent Document 1).
[0003]
[Patent Document 1]
JP 2001-345553 A
[0004]
[Problems to be solved by the invention]
By the way, in the method of joining a printed circuit board and a flexible board by alkane connection, since the joining strength between the printed circuit board and the flexible board is extremely large, after joining the printed circuit board and the flexible board by alkane connection, It is difficult to remove from the printed circuit board.
[0005]
However, this has the advantage that the bonding strength is high, but if a failure occurs in the flexible substrate after joining the printed circuit board and the flexible substrate, not only the defective flexible substrate is discarded, but also the failure. In this respect, the printed circuit board which has nothing to do has to be discarded, and in this respect, repairability and economic efficiency are poor.
[0006]
The present invention has been made in view of the above circumstances, and its purpose is to improve repairability and economic efficiency in the case where a failure occurs in the flexible substrate after joining the printed circuit board and the flexible substrate by alkane connection. and to provide a substrate connection methods that can.
[0007]
[Means for Solving the Problems]
According to the substrate connection method described in claim 1, when a printed circuit board and the flexible board are bonded by alkanes connection, even if the defective flexible substrate occurred after bonding the print substrate and the flexible substrate The resin of the original flexible board is removed so that the conductor of the original flexible board is exposed, and alkanes are applied to at least one of the conductor of the original flexible board and the conductor of the new flexible board. By pressing and pressing a flexible substrate to the original flexible substrate, the printed circuit board and the new flexible substrate can be joined by alkane connection via the original flexible substrate . Thereby, it is possible to reuse a printed circuit board that has nothing to do with a defect without discarding it, and it is possible to improve repairability and economy.
[0008]
According to the substrate connection method described in claim 2, since the original flexible substrate is cut halfway before at least the new flexible substrate is heated and pressure-bonded to the original flexible substrate, the electrical flexibility of the original flexible substrate can be reduced. A physically unnecessary portion can be removed.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
(First embodiment)
A first embodiment of the present invention will be described below with reference to FIGS. First, in FIG. 2, a printed circuit board 1 has a base plate 2 made of, for example, a glass epoxy base material, and a set of printed wiring terminals 3 made of, for example, copper foil is formed on the surface thereof. A set of preliminary printed wiring terminals 4 having the same shape as the set of printed wiring terminals 3 is formed. In this case, the printed circuit board 1 may be one in which the base plate 2 is composed of a composite material plate or a ceramic substrate having a resin as a base material, and a printed wiring terminal 3 made of a gold foil, a silver foil, or a gold-plated conductor. Alternatively, a preliminary printed wiring terminal 4 may be formed. A thin solder layer (not shown) called a solder leveler is formed on the surface of each of the printed wiring terminals 3 and the spare printed wiring terminals 4. In this case, the solder forming the solder layer is a eutectic solder, and its melting point is about 183 ° C.
[0013]
The flexible substrate 5 is composed of a film 6 made of a thermoplastic resin called PEN (polyethylene naphthalate), for example, and is formed to be extremely thin as compared with the printed circuit board 1, and its melting point is about 270 to 280. ° C. For example, a set of copper foils 7 (conductors in the present invention) is formed on the surface of the flexible substrate 5. In this case, the flexible substrate 5 may be composed of a film 6 made of a thermoplastic resin called PET (polyethylene terephthalate), PEEK (polyether ether ketone) or PPS (polyphenylene sulfide), Also, a gold paste may be formed.
[0014]
Next, a method of joining the printed board 1 and the flexible board 5 by alkane connection will be described. In this case, the printed circuit board 1 and the flexible printed circuit board 5 are joined to each other by an alkane connection by sequentially performing an alkane coating process and a temperature rising and pressing process.
[0015]
First, in the alkane coating process, alkanes 8 are coated on the surface of the solder layer of the printed wiring terminal 3 of the printed circuit board 1 (see (b) in FIG. 2). In this case, instead of applying the alkanes 8 to the surface of the solder layer of the printed wiring terminal 3 of the printed circuit board 1, the alkanes 8 may be applied to the surface of the copper foil 7 of the flexible substrate 5, that is, the printed circuit board. The alkanes 8 may be applied to at least one of the surface of the solder layer of one printed wiring terminal 3 and the surface of the copper foil 7 of the flexible substrate 5.
[0016]
As a method of applying the alkanes 8, it may be applied using a brush-like or roller-like applying means, or may be applied using a spray. Further, the alkanes 8 can be used as long as they are not saturated but may be any suitable saturated hydrocarbon, and may contain impurities that are harmless to the junction. Further, it is desirable that the boiling point of the alkane as the main component of the alkanes 8 is in an appropriate range lower than the melting point of the thermoplastic resin forming the film of the flexible substrate 5.
[0017]
Next, in the temperature rising and pressing step, the flexible substrate 5 is heated and pressure bonded to the printed circuit board 1 with the printed wiring terminals 3 of the printed circuit board 1 and the copper foil 7 of the flexible circuit board 5 facing each other (in FIG. 2 (c )reference). In addition, as a method of temperature rising and pressure bonding, a heat tool such as a metal block heated and heated may be pressed against the flexible substrate 5 or may be ultrasonically heated in a state where the flexible substrate 5 is pressed against the printed circuit board 1. Also good.
[0018]
In this way, the printed circuit board 1 and the flexible substrate 5 can be joined by alkane connection. In this case, when the flexible substrate 5 is welded to the printed circuit board 1, the bonding strength between the printed circuit board 1 and the flexible circuit board 5 is extremely high.
[0019]
Now, let us consider a case where a defect occurs in the flexible substrate 1 after the printed circuit board 1 and the flexible substrate 5 are joined together by alkane connection in this way. In this case, first, the original flexible substrate 5 is cut halfway (see (d) in FIG. 3), and the electrically and physically unnecessary portions of the original flexible substrate 5 are removed. Even if the original flexible substrate 5 is left as it is, there is no need to cut the original flexible substrate 5 in the middle if there is no electrical or physical adverse effect.
[0020]
Next, a new flexible substrate 9 having the same structure as that of the flexible substrate 5 to be used first is prepared, and the alkane coating process described above is performed again, and alkanes are formed on the surface of the solder layer of the preliminary printed wiring terminal 4 of the printed circuit board 1. 8 is applied (see (e) in FIG. 3). Also in this case, instead of applying the alkanes 8 to the surface of the solder layer of the preliminary printed wiring terminal 4 of the printed circuit board 1, the alkanes 8 are formed on the surface of the pair of copper foils 10 formed on the new flexible substrate 9. May be applied.
[0021]
Then, the temperature increasing and crimping step described above is performed again, and the new flexible substrate 9 is attached to the printed circuit board 1 with the preliminary printed wiring terminals 4 of the printed circuit board 1 and the copper foil 10 of the new flexible circuit board 9 facing each other. The temperature is increased by pressure bonding (see (f) in FIG. 3).
[0022]
In this way, even if a failure occurs in the flexible substrate 5 after the printed circuit board 1 and the flexible substrate 5 are joined by the alkane connection, the printed circuit board 1 that has nothing to do with the failure is reused and printed. The board | substrate 1 and the new flexible board | substrate 9 can be joined by alkane connection. By the way, in the above-described configuration, a configuration in which one set of preliminary printed wiring terminals 4 is formed on the printed circuit board 1 is explained. The structure in which the terminal 4 is formed may be sufficient.
[0023]
As described above, according to the first embodiment, when the printed circuit board 1 and the flexible circuit board 5 are joined by the alkane connection, the printed circuit board 1 on which the preliminary printed wiring terminals 4 are formed is used. Even when a failure occurs in the flexible substrate 5 after joining the flexible substrate 5 to the flexible substrate 5, for example, an alkane is applied to the surface of the solder layer of the preliminary printed wiring terminal 4 of the printed circuit board 1, and a new flexible substrate 9 is formed. Can be joined to the printed circuit board 1 by alkane connection. Thereby, the printed circuit board 1 which has nothing to do with defects can be reused without being discarded, and repairability and economic efficiency can be improved.
[0024]
(Second embodiment)
Next, a second embodiment of the present invention will be described with reference to FIGS. The description of the same parts as those in the first embodiment will be omitted, and different parts will be described. In the first embodiment described above, the preliminary printed wiring terminals 4 are formed on the printed circuit board 1, whereas in the second embodiment, the preliminary copper foil is formed on the flexible substrate. It is.
[0025]
That is, in FIG. 4, a printed wiring terminal 12 is formed on the surface of the printed circuit board 11, and a solder layer 13 is formed on the surface of the printed wiring terminal 12. On the other hand, a copper foil 15 is formed on the front surface (lower surface in FIG. 4) of the flexible substrate 14, and a spare copper foil 16 (referred to in the present invention) on the back surface (upper surface in FIG. 4). A spare conductor) is formed, and a solder layer 17 is formed on the surface of the spare copper foil 16. The copper foil 15 and the spare copper foil 16 are electrically connected by a via 18.
[0026]
In this case, in the alkane coating process, alkanes 19 are coated on the surface of the solder layer 13 of the printed wiring terminal 12 of the printed circuit board 11 (see FIG. 4B). Also in this case, instead of applying the alkanes 19 to the surface of the solder layer 13 of the printed wiring terminal 12 of the printed circuit board 11, the alkanes 19 may be applied to the surface of the copper foil 15 of the flexible substrate 14.
[0027]
Next, in the temperature rising and pressing step, the flexible substrate 14 is heated and pressure bonded to the printed circuit board 11 with the printed wiring terminals 12 of the printed circuit board 11 and the copper foil 15 of the flexible circuit board 14 facing each other (in FIG. )reference). At this time, when a pressure is applied by a jig (illustrated), the film made of the thermoplastic resin of the flexible substrate 14 and the spare copper foil 16 are deformed.
[0028]
Now, also here, consider a case where a defect occurs in the flexible substrate 14 after the printed circuit board 11 and the flexible substrate 14 are joined together by alkane connection. Also in this case, first, the original flexible substrate 14 is cut halfway (see (d) in FIG. 5), and the electrically and physically unnecessary portions of the original flexible substrate 14 are removed.
[0029]
Next, a new flexible substrate 20 having the same structure as the flexible substrate 14 to be used first is prepared, and the alkane coating process described above is performed again. In this case, the solder layer 17 of the spare copper foil 16 of the flexible substrate 14 is formed. Alkanes 19 are applied to the surface (see (e) in FIG. 5). Also in this case, instead of applying alkanes 19 to the surface of the solder layer 17 of the spare copper foil 16 of the flexible substrate 14, the alkanes 19 are applied to the surface of the copper foil 21 formed on the new flexible substrate 20. May be.
[0030]
Then, the temperature increasing / compression bonding process described above is performed again, and the new flexible substrate 20 is replaced with the original flexible substrate 14 with the spare copper foil 16 of the original flexible substrate 14 and the copper foil 21 of the new flexible substrate 20 facing each other. The temperature is crimped to the flexible substrate 14 (see (f) in FIG. 5).
[0031]
In this way, even if a failure occurs in the flexible substrate 14 after the printed circuit board 11 and the flexible substrate 14 are joined by the alkane connection, the printed circuit board 11 that has nothing to do with the failure is reused and printed. The substrate 11 and the new flexible substrate 20 can be joined by alkane connection via the original flexible substrate 14. By the way, also in this case, the structure by which the 2 or more spare copper foil 16 is formed in the flexible substrate 14 may be sufficient. In addition, every time when a defect occurs in the flexible substrate joined by the alkane connection, the flexible substrate may be stacked in multiple stages by joining the new flexible substrate and the flexible substrate in which the defect has occurred by the alkane connection. good.
[0032]
As described above, according to the second embodiment, when the printed circuit board 11 and the flexible circuit board 14 are joined by the alkane connection, the flexible circuit board 14 on which the spare copper foil 16 is formed is used. Even if a failure occurs in the flexible substrate 14 after joining the flexible substrate 14, for example, an alkane is applied to the surface of the solder layer 17 of the spare copper foil 16 of the original flexible substrate 14 to create a new flexible substrate. The printed circuit board 11 and the new flexible circuit board 20 can be joined to each other by the alkane connection via the original flexible circuit board 14 by temperature-pressing and compressing 20 to the original flexible circuit board 14. As a result, in the same manner as that described in the first embodiment, the printed circuit board 11 that has nothing to do with a defect can be reused without being discarded, and repairability and economic efficiency can be improved. .
[0033]
(Third embodiment)
Next, a third embodiment of the present invention will be described with reference to FIGS. The description of the same parts as those of the second embodiment will be omitted, and different parts will be described. In the second embodiment described above, the solder layer 13 is formed on the surface of the printed wiring terminal 12 of the printed circuit board 11 and the solder layer 17 is formed on the surface of the spare copper foil 16 of the flexible substrate 14. In contrast, in the third embodiment, a solder layer is formed on the surface of the copper foil of the flexible substrate.
[0034]
That is, in FIG. 6, a printed wiring terminal 32 is formed on the surface of the printed board 31. On the other hand, a copper foil 34 is formed on the surface of the flexible substrate 33 (the lower surface in FIG. 6), and a solder layer 35 is formed on the surface of the copper foil 34.
[0035]
In this case, in the alkane coating process, alkanes 36 are coated on the surface of the printed wiring terminal 32 of the printed board 31 (see (b) in FIG. 6). Also in this case, instead of applying the alkanes 36 to the surface of the printed wiring terminal 32 of the printed board 31, the alkanes 36 may be applied to the surface of the solder layer 35 of the copper foil 34 of the flexible substrate 33.
[0036]
Next, in the temperature rising and pressing step, the flexible substrate 33 is heated and pressure bonded to the printed circuit board 31 with the printed wiring terminals 32 of the printed circuit board 31 and the copper foil 34 of the flexible printed circuit board 33 facing each other (in FIG. )reference). Also at this time, the film made of the thermoplastic resin of the flexible substrate 33 is deformed by applying pressure by a jig (illustrated).
[0037]
Now, also here, consider a case where a defect occurs in the flexible substrate 33 after the printed circuit board 31 and the flexible substrate 33 are joined together by an alkane connection. Also in this case, first, the original flexible substrate 33 is cut halfway (see FIG. 7D), and the electrically and physically unnecessary portions of the original flexible substrate 33 are removed.
[0038]
Next, in this case, the thermoplastic resin of the flexible substrate 33 is removed so that the copper foil 34 of the flexible substrate 33 is exposed (see (e) in FIG. 7). As a method for removing the thermoplastic resin from the flexible substrate 33, a heated blade or the like may be used.
[0039]
Next, a new flexible substrate 37 having the same structure as the flexible substrate 33 to be used previously is prepared, and the alkane coating process described above is performed again. In this case, the alkanes 36 are formed on the surface of the copper foil 34 of the flexible substrate 33. Is applied (see (f) in FIG. 7). Also in this case, instead of applying the alkanes 36 to the surface of the copper foil 34 of the flexible substrate 33, the alkane is applied to the surface of the solder layer 39 formed on the surface of the copper foil 38 formed on the new flexible substrate 37. Class 36 may be applied.
[0040]
Then, the temperature increasing and pressing step described above is performed again, and the new flexible substrate 37 is placed in the original flexible substrate 37 with the copper foil 34 of the original flexible substrate 33 and the copper foil 38 of the new flexible substrate 37 facing each other. The substrate 33 is heated and pressed (see (g) in FIG. 8).
[0041]
In this way, even if a failure occurs in the flexible substrate 33 after the printed circuit board 31 and the flexible substrate 33 are joined by the alkane connection, the printed circuit board 31 that has nothing to do with the failure is reused and printed. The substrate 31 and the new flexible substrate 37 can be joined by alkane connection via the original flexible substrate 33. Also, in this case, every time a failure occurs in the flexible substrate joined by the alkane connection, the flexible substrate is stacked in multiple stages by joining the new flexible substrate and the defective flexible substrate by the alkane connection. It may be.
[0042]
As described above, according to the third embodiment, when the printed circuit board 31 and the flexible circuit board 33 are bonded by the alkane connection, a defect occurs in the flexible circuit board 33 after the printed circuit board 31 and the flexible circuit board 33 are bonded. Even in this case, the resin of the flexible substrate 33 is removed so that the copper foil 34 of the flexible substrate 33 is exposed, and, for example, an alkane is applied to the surface of the copper foil 34 of the flexible substrate 33 to form a new flexible substrate. By temperature-pressing and bonding 37 to the original flexible board 33, the printed board 31 and the new flexible board 37 can be joined to each other via the original flexible board 33 by alkane connection. As a result, in the same manner as described in the first and second embodiments described above, the printed circuit board 31 that has nothing to do with the defect can be reused without being discarded. Can be increased.
[0043]
(Other examples)
The present invention is not limited to the embodiments described above, and can be modified or expanded as follows.
The printed board may be a multilayer board manufactured by a batch multilayer press method.
[Brief description of the drawings]
FIG. 1 is a diagram schematically showing a first embodiment of the present invention. FIG. 2 is a schematic diagram showing a process. FIG. 3 is a diagram corresponding to FIG. 2. FIG. 4 is a schematic diagram showing a process of a second embodiment of the invention. [FIG. 5] FIG. 4 equivalent diagram [FIG. 6] Schematic diagram showing the steps of the third embodiment of the present invention [FIG. 7] FIG. 6 equivalent diagram [FIG. 8] FIG.
In the drawings, 1 is a printed board, 3 is a printed wiring terminal, 4 is a preliminary printed wiring terminal, 5 is a flexible board, 7 is a copper foil (conductor), 8 is an alkane, 9 is a new flexible board, and 10 is a copper foil. (Conductor), 11 is a printed board, 12 is a printed wiring terminal, 14 is a flexible board, 15 is a copper foil (conductor), 16 is a spare copper foil (spare conductor), 19 is an alkane, 20 is a new flexible board, 21 is a copper foil (conductor), 31 is a printed board, 32 is a printed wiring terminal, 33 is a flexible board, 34 is a copper foil (conductor), 36 is an alkane, 37 is a new flexible board, 38 is a copper foil (conductor) ).

Claims (2)

Applying alkanes to at least one of the printed wiring terminal of the printed circuit board and the conductor of the flexible circuit board, temperature-bonding the flexible circuit board to the printed circuit board, and joining the printed circuit board and the flexible circuit board,
When the error occurs when the flexible substrate after bonding the print substrate and the flexible substrate, the original resin of the flexible substrate is removed so that the conductor of the original flexible substrate is exposed, the original flexible board conductors And alkanes are applied to at least one of the conductors of the new flexible board, the new flexible board is heated and pressure-bonded to the original flexible board, and the printed board and the new flexible board are passed through the original flexible board. A substrate connection method comprising bonding. In the board | substrate connection method described in Claim 1,
A substrate connection method comprising cutting an original flexible substrate halfway before at least temperature-bonding a new flexible substrate to the original flexible substrate.

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