TWI620481B - Method for manufacturing flexible printed circuit board and intermediate product for manufacturing flexible printed circuit board - Google Patents

Abstract

The present invention provides a method of manufacturing a flexible printed circuit board and an intermediate product thereof, which can reduce damage to a cathode roller and can easily share the same continuous production line with a single-sided circuit board or a double-sided circuit board; the flexible printing The manufacturing method of the circuit board (P) includes a substrate forming step, a connecting step, and a fixing step, and in the substrate forming step, forming a substrate (10) provided with a thin plate-like protruding portion (44), the thin plate-shaped protruding portion (44) The thickness is smaller than the other portions of the substrate (10) and the conductor layer (42) is provided on the surface, and the thin plate-like protrusions (44) are different from one end side and the other end side in the longitudinal direction of the substrate (10). The surface is connected to the substrate (10); in the connecting step, the conductor layer (42) of the thin plate-like protrusion (44) provided on one end side of the substrate (10) is disposed on the other substrate (10) The conductor layers (42) of the thin plate-like protrusions (44) on the other end side are in contact to form a connection portion; in the fixing step, the connection is made by the connection members (60) respectively disposed on one side and the other side of the connection portion. Partially fixed.

Description

Method for manufacturing flexible printed circuit board and intermediate product for manufacturing flexible printed circuit board

The present invention relates to a method of manufacturing a flexible printed circuit board and an intermediate product for manufacturing a flexible printed circuit board.

In recent years, with the miniaturization and high performance of electronic devices, there has been an increasing demand for higher density of flexible printed circuits (hereinafter referred to as "circuit boards"). The flexible circuit board comprises a single-sided circuit board, a double-sided circuit board, and a multi-layer circuit board, wherein the single-sided circuit board and the double-sided circuit board are mainly manufactured by a roll-to-roll continuous manufacturing method. The multilayer circuit board is mainly manufactured by a short sheet-like cutting manufacturing method in which the cut sheets are bonded and moved. It can be seen that the production line for manufacturing the single-sided circuit board and the double-sided circuit board is different from the production line for manufacturing the multilayer circuit board.

Further, in the double-sided circuit board which can be manufactured by the continuous manufacturing method, when a plating method is used for the connection between the layers, a continuous plating line can be used, so that a plating film having a small thickness deviation and uniformity can be formed (within ±10%) . On the other hand, in the case of a multilayer circuit board, In the short-cut manufacturing method, the thickness deviation of the plating film is large (±30% or more) under the influence of variations in electric field concentration.

In addition, single-sided boards and double-sided boards can be manufactured using the same production line. However, the multi-layer circuit board is manufactured in a different production line from the above by the short-cut manufacturing method, and therefore, when the accepted order includes a single-sided circuit board or a double-sided circuit board and a multi-layer circuit board, it is necessary to frequently Switching production lines leads to increased costs. Therefore, it has been demanded to develop a method of manufacturing a multilayer circuit board which can be manufactured using the same continuous production line as a single-sided circuit board or a double-sided circuit board.

As a technique capable of manufacturing a multilayer circuit board in the above-described continuous production line, there are, for example, the techniques disclosed in Patent Documents 1 to 5. Among them, in the methods disclosed in Patent Documents 1 to 4, a plurality of short-form substrates are electrically connected by a connecting member having a conductive portion.

Further, in the method disclosed in Patent Document 5, the patterned substrates are connected to each other by a conductive tape.

[Previous Technical Literature]

[Patent Literature]

Patent Document 1: Japanese Gazette, License No. 4838155

Patent Document 2: Japanese Gazette, License No. 5029086

Patent Document 3: Japanese Gazette, Special Open 2007-294597

Patent Document 4: Japanese Gazette, Special Open 2009-277810

Patent Document 5: Japanese Gazette, Charter No. 5151313

However, when the substrates are electrically connected to each other by a connecting member having a conductive portion as shown in Patent Documents 1 to 4, the substrates are connected to each other. The thickness becomes larger. Therefore, it is difficult to wind up into a roll shape, and it is difficult to manufacture by a continuous manufacturing method. In addition, since the substrates are connected to each other using the connecting member, damage to the cathode roller in the plating line may be caused. In addition, the uniformity of the plating film may be damaged due to the presence of the connecting member. In addition, since the connection member is present, the unevenness is generated in the connection body of the substrate. Therefore, the lamination property of the dry film (photoresist layer) when the pattern is formed on the surface layer is lowered.

Further, in Patent Document 5, since the thickness at the end portion where the substrates are connected to each other is increased, the same problem as described above is basically caused.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a method for manufacturing a flexible printed circuit board and an intermediate product for manufacturing the same, in which a method for manufacturing the flexible printed circuit board can be reduced The damage caused by the cathode roll can easily be shared with the single continuous circuit board or the double-sided circuit board, and the pattern formation of the surface layer can be improved.

In order to solve the above problems, in a method of manufacturing a flexible printed circuit board according to a first aspect of the present invention, a plurality of substrates are connected to each other to form a flexible printed circuit board, wherein a plurality of laminates are laminated in the substrate, and A conductor layer is respectively disposed on one side surface and the other side surface of the substrate, and the manufacturing method of the flexible printed circuit board is characterized by comprising a substrate forming step, a connecting step, and a fixing step, in the substrate shape In the forming step, a substrate provided with a thin plate-like protruding portion is formed, wherein the thin plate-shaped protruding portion has a thickness smaller than other portions of the substrate and a conductor layer is provided on the surface, and the thin plate-shaped protruding portion is oriented in the longitudinal direction of the substrate One end side and the other end side are connected to the mutually different surfaces, and are disposed on the substrate; in the connecting step, the conductor layer provided on the one end side of the substrate is disposed on the other end of the other substrate The conductor layers of the thin plate-like projecting portions are in contact with each other to form a connecting portion. In the fixing step, the connecting portions are fixed by connecting members respectively disposed on one surface side and the other surface side of the connecting portion.

Further, in another aspect of the invention, it is preferable that the conductor layer and the conductor layer of the one side surface of the substrate are connected to the thin plate-like protrusion and the conductor layer and the conductor layer on the other side surface of the substrate. The connecting thin plate-like protrusions have two connecting portions between the corresponding thin plate-like protrusions of the other substrate in the width direction perpendicular to the longitudinal direction of the substrate, and the two connecting portions are different through two The connection is such that the conductor layers on the thin plate-like projections are connected in an X-shape in the width direction.

Furthermore, in another aspect of the invention, it is preferable that a gap portion is provided between two thin plate-like protruding portions arranged along a width direction of the substrate, and the gap portion is set to be lower. The gap portion of the degree, that is, when the thin plate-like projections are bent to protrude from different surfaces of the substrate in the joining step, the thin plate-like projections do not interfere with each other.

Further, in other aspects of the invention, it is preferred that the laminate comprises a double-sided laminate and a single-sided laminate, wherein The double-sided laminate is provided with a conductor layer on each surface of the substrate, the single-sided laminate is provided with a conductor layer on one surface of the substrate, and the one-side laminate is in the one end side and the other end side in the longitudinal direction A thin plate-like projection is provided on at least one end side, and a single-sided laminate is fixed on one side surface and the other side surface of the double-sided laminate by an adhesive layer, respectively.

Furthermore, in another aspect of the invention, it is preferred that the adhesive layer is disposed to have a length greater than a length of the substrate of the double-sided laminate; and further, the adhesive layer is set to have a length smaller than a single side. The length of the portion of the sheet-like projection is present in the laminate, but is greater than the length of the portion of the single-sided laminate where the sheet-like projection is not present.

Further, a second aspect of the present invention provides an intermediate product for manufacturing a flexible printed circuit board in which a plurality of substrates are connected to each other to manufacture a flexible printed circuit board, wherein the substrate is laminated a plurality of laminates, and a conductor layer is respectively disposed on one side surface and the other side surface of the substrate, wherein the intermediate product is characterized by: a thin plate-like protrusion provided on the substrate and having a thickness smaller than that of the substrate a portion in which a conductor layer is provided on a surface of the thin plate-like projecting portion, and the thin plate-like projecting portion is provided on the substrate in a state in which one end side and the other end side in the longitudinal direction of the substrate are connected to mutually different surfaces; a portion formed by contacting a conductor layer of a thin plate-like protruding portion provided on one end side of the substrate with a conductor layer of a thin plate-like protruding portion provided on the other end side of the other substrate; and connecting members respectively disposed at the connection One side and the other side of the portion are fixed and the connecting portion is fixed.

According to the present invention, damage to the cathode roller can be reduced, and the same continuous production line can be shared with the single-sided circuit board or the double-sided circuit board, and the pattern formation property of the surface layer can be improved.

10‧‧‧Rectangular substrate

20‧‧‧Double-sided laminate (corresponding to laminate)

21‧‧‧Substrate

22‧‧‧Conductor layer

23‧‧‧ circuit pattern

30‧‧‧ adhesive layer

40‧‧‧Single-sided laminate (corresponding to laminate)

41‧‧‧Substrate

42‧‧‧Conductor layer

44‧‧‧ Lengthwise convex part (corresponding to thin plate-like protrusion)

45‧‧‧ Length direction recess

46‧‧‧ circuit pattern

50‧‧‧Interlayer connection through hole

60‧‧‧Connecting parts

61‧‧‧Insulating film layer

62‧‧‧Conductor layer

63‧‧‧ adhesive layer

70‧‧‧ intermediates

80‧‧‧Electrical film

90‧‧‧Electroplated film

100‧‧‧Rectangular Shape Substrate

110‧‧‧Double-sided laminate

111‧‧‧Substrate

112‧‧‧Conductor layer

120‧‧‧bonding layer

130‧‧‧Single-sided laminate

131‧‧‧Substrate

132‧‧‧Conductor layer

140‧‧‧Interlayer connection through hole

150‧‧‧Connecting parts

151‧‧‧Adhesive layer

152‧‧‧ conductor layer

160‧‧‧Electrical film

170‧‧‧Electroplated film

180‧‧‧ circuit pattern

200‧‧‧Soft printed circuit board

P‧‧‧Soft printed circuit board

Fig. 1 is a side sectional view showing the configuration of a rectangular substrate for manufacturing a flexible printed circuit board according to an embodiment of the present invention.

Fig. 2 is a top plan view showing the constitution of the rectangular substrate of Fig. 1.

Fig. 3 is a top view showing a state in which a portion corresponding to a recess in the longitudinal direction is cut out from a rectangular sheet as a raw material of a single-sided laminate to form a single-sided laminate.

Fig. 4 is a top view showing a state in which a rectangular sheet as a single-sided laminate raw material is cut in a crank shape to form a single-sided laminate.

5 is a side cross-sectional view showing a state in which rectangular substrates adjacent in the longitudinal direction are arranged such that conductor layers of each other overlap each other.

Fig. 6 is a top view showing a state in which a rectangular substrate adjacent in the longitudinal direction is placed so as to overlap each other with a conductor layer, and a jig used when the longitudinal direction convex portion is pressed.

Fig. 7 is a side sectional view showing a state in which the upper and lower positions of the longitudinal direction convex portions are interchanged.

Fig. 8 is a top view showing a state in which the upper and lower positions of the longitudinal direction convex portions are interchanged.

Fig. 9 is a side sectional view showing the configuration of the vicinity of the portion A and the vicinity of the portion B in Fig. 8.

Fig. 10 is a side cross-sectional view showing a state in which a connecting member is disposed on a portion where the longitudinal direction convex portions are connected to each other, and the connecting member is pressure-bonded after being disposed.

Fig. 11 is a side sectional view showing a state in which the adhesive is melted and flows out to fill the gap after the connection member in Fig. 10 is disposed.

Figure 12 is a top plan view showing the arrangement state of the connecting member of Figure 10.

Figure 13 is a side cross-sectional view showing a state in which a conductive film is formed on the intermediate product of Figure 10.

Fig. 14 is a side sectional view showing a state after a plating film is formed on the electroconductive film of Fig. 13.

Fig. 15 is a side sectional view showing a state in which a circuit pattern is formed after the plating film of Fig. 14 is formed.

Fig. 16 is a side sectional view showing a state in which the intermediate product in which the circuit pattern of Fig. 15 is formed is cut.

Fig. 17 is a side sectional view showing the configuration of a rectangular substrate according to a modification of the present invention.

Figure 18 is a top plan view showing the constitution of the rectangular substrate of Figure 17.

Fig. 19 is a top plan view showing the configuration of a rectangular substrate according to a modification of the present invention.

Fig. 20 is a side sectional view showing the configuration of a conventional rectangular-shaped substrate.

Fig. 21 is a side cross-sectional view showing a state in which the rectangular-shaped substrate of Fig. 20 is connected by a connecting member using a conventional manufacturing method.

Fig. 22 is a side cross-sectional view showing a state in which a conductive film is formed on a member after the substrate of Fig. 21 is connected to a conventional manufacturing method.

Fig. 23 is a view showing a conventional manufacturing method, and is shown in Fig. 22 A side cross-sectional view showing a state in which a plating film is formed on a member after the conductive film.

Fig. 24 is a side cross-sectional view showing a state in which a circuit pattern is formed on a member after the plating film of Fig. 23 is formed, relating to a conventional manufacturing method.

Fig. 25 is a side cross-sectional view showing a state in which a member after forming the circuit pattern of Fig. 24 is cut, in a conventional manufacturing method.

Fig. 26 is a bottom view showing the configuration of a conventional connecting member.

Hereinafter, a method of manufacturing the flexible printed circuit board P according to an embodiment of the present invention will be described. In the following description, the method of manufacturing the flexible printed circuit board P will be described, and the intermediate printed product 70 obtained in the flexible printed circuit board P and its manufacturing process will also be described.

In the following description, the XYZ axis is used for convenience of understanding, and the right side of FIG. 1 is set to the X1 side and the left side is set to the X2 side. In addition, the upper side of FIG. 1 is set to the Z1 side, and the lower side is set to the Z2 side. In addition, the upper side of FIG. 2 is set to the Y1 side, and the lower side is set to the Y2 side. Further, the X direction corresponds to the longitudinal direction of the rectangular substrate 10, and the Y direction corresponds to the width direction of the rectangular substrate 10.

1 is a side cross-sectional view showing the configuration of a rectangular substrate 10 for manufacturing a flexible printed circuit board P. In addition, FIG. 2 is a top view showing the configuration of the rectangular substrate 10.

In manufacturing the flexible printed circuit board P of the present embodiment, a rectangular substrate 10 (corresponding to the substrate) as shown in FIGS. 1 and 2 is first formed (corresponding to the substrate forming step). The rectangular substrate 10 has a double-sided laminate 20 (corresponding to a laminate) and a single-sided laminate 40 (corresponding to a laminate). The double-sided laminate 20 is provided with a conductor layer 22 on both sides of a substrate 21 having flexibility and electrical insulation. The conductor layer 22 is, for example, a metal foil such as a copper foil. However, the material of the conductor layer 22 may be any other material as long as it has conductivity. Further, the base material 21 is formed of, for example, a polyimide film, but the material of the base material 21 may be any other material as long as it has flexibility and insulation properties.

As shown in FIG. 1, a circuit pattern 23 is formed on each of the conductor layers 22 by a photofabrication method such as etching. Then, after the circuit pattern 23 is formed, the adhesive layer 30 is laminated on each of the conductor layers 22, respectively. The adhesive layer 30 may be included in the structure of the double-sided laminate 20, or may be included in the structure of the single-sided laminate 40, and may be other than the double-sided laminate 20 and the single-sided laminate 40. structure.

After the adhesive layer 30 is laminated on the upper and lower sides of the double-sided laminate 20, the single-sided laminate 40 is further laminated on the upper and lower sides, respectively, whereby the individual single-sided laminates 40 are bonded by the adhesive layer 30. On the double-sided laminate 20. Each of the single-sided laminates 40 has a base material 41 having a flexibility and electrical insulation, and a conductor layer 42 provided on one side of the base material 41. Further, the structure of the base material 41 is the same as that of the above-described base material 21, and the configuration of the conductor layer 42 is the same as that of the above-described conductor layer 22.

Thereby, a plurality of layers having a total of four conductor layers 22, 42 are formed. The structure, that is, the rectangular substrate 10. Next, the rectangular substrate 10 is subjected to, for example, NC drilling processing or the like to form the interlayer connection via 50. After the subsequent plating treatment, the interlayer connection via 50 becomes electrically conductive.

The interlayer connection via 50 may be a direct through hole penetrating the rectangular substrate 10, or may be a conformal via formed using a carbon dioxide laser or the like, using a UV-YAG laser. A through hole or a non-through hole such as a direct via formed may be a combination thereof. Further, the interlayer connection via 50 may also be a buried via formed on the double-sided laminate 20, but in this case, the buried via must be formed before the adhesive layer 30 is laminated.

Here, as shown in FIG. 1, in the rectangular substrate 10, the upper side single-sided laminated board 40 and the lower side single-sided laminated board 40 are respectively provided with the longitudinal direction convex part 44 and the longitudinal direction recessed part 45. The longitudinal direction convex portion 44 and the longitudinal direction concave portion 45 are formed by cutting the longitudinal end portion of the single-sided laminate 40, and are transmitted through one side in the width direction (Y direction) of the single-sided laminate 40 (Y1 side). It is formed by cutting so as to protrude from the other side (Y2 side) in the width direction. Further, the longitudinal direction convex portion 44 is provided to have a thickness smaller than that of the other portion of the rectangular substrate 10, and the longitudinal direction convex portion 44 corresponds to the thin plate-like protruding portion.

The lengthwise convex portion 44 and the longitudinal direction concave portion 45 are preferably formed in a stage before the single-sided laminate 40 is laminated. In this case, as shown in FIG. 3, a portion corresponding to the longitudinal direction concave portion 45 can be cut out from the rectangular sheet S which is a material of the single-sided laminate 40, thereby forming the single-sided laminate 40. Figure 3 is a view showing the cutting of the concave portion 45 corresponding to the longitudinal direction from the sheet S. A top view of the portion when forming the single-sided laminate 40.

However, as shown in FIG. 4, a sheet which is a raw material of the one-side laminate 40 may be cut in a crank shape. 4 is a top view showing a state in which the sheet S is cut in a crank shape to form a single-sided laminate 40. In the case where the cutting is performed as shown in FIG. 4, the waste of the sheet can be reduced, so that the cost can be further reduced.

Further, as described below, a predetermined gap exists in the width direction (Y direction) between the longitudinal direction convex portion 44 on the upper surface side and the longitudinal direction convex portion 44 on the lower surface side. Therefore, the longitudinal direction convex portion 44 on the upper surface side and the longitudinal direction convex portion 44 on the lower surface side are curved in the direction in which the vertical direction is different, and the longitudinal direction convex portion adjacent in the width direction (Y direction) can be configured. 44 will not interfere with each other.

Here, in the case where the longitudinal direction convex portion 44 and the longitudinal direction concave portion 45 are formed in the stage before the single-sided laminate 40 is laminated, it is preferable to adjoin the width direction (Y direction) in consideration of an error or the like at the time of lamination. There is a gap portion of 1 mm or more between the longitudinal direction convex portions 44. Further, in the case of performing cutting in a crank shape, the predetermined gap may be a gap portion corresponding to the width of the tool used for cutting.

Further, the longitudinal direction convex portion 44 and the longitudinal direction concave portion 45 may be formed after the single-sided laminate 40 is laminated on the double-sided laminate 20 and the adhesive layer 30. In this case, since the cutting is performed after lamination, it is not necessary to consider the misalignment error at the time of lamination at the time of cutting.

Further, in the present embodiment, the double-sided laminate 20 and the adhesive layer 30 are provided such that their length is smaller than one end side of the single-sided laminate 40 and another The length between the end portions of the longitudinal direction convex portions 44 on one end side is larger than the length between the one end side of the one-side laminate 40 and the end portion of the longitudinal direction concave portion 45 on the other end side. Therefore, as shown in FIG. 2, the adhesive layer 30 is exposed in the longitudinal direction concave portion 45. In addition, the adhesive layer 30 may be bonded to the connecting member 60 to be described later. In this case, when wet etching or the like is performed, it is possible to prevent the chemical solution or the like from entering the gap portion.

In addition, as shown in FIG. 1, the length of the substrate 21 of the double-sided laminate 20 is set to be smaller than the length of the conductor layer 22 and the adhesive layer 30. Thereby, the upper single-sided laminate 40 is easily bent toward the lower side, and similarly, the lower single-sided laminate 40 is easily bent toward the upper side. Thereby, the conductor layers 42 are easily brought into contact with each other (connected) as described below. However, it is also possible to differ from the configuration of FIG. 1 in that the length of the substrate 21 is set to be larger than the length of the conductor layer 22 and the adhesive layer 30.

Next, as shown in FIGS. 5 and 6, the rectangular substrates 10 adjacent in the longitudinal direction (X direction) are disposed such that their conductor layers 42 overlap each other. That is, the state in which the portions in the vicinity of the end portions of the longitudinal direction convex portions 44 are overlapped with each other is disposed. In this case, the conductor layer 42 on the lower surface side (Z2 side) of the rectangular substrate 10 on the one end side (X1 side) is in contact with the conductor layer 42 on the upper surface side (Z1 side) of the rectangular substrate 10 on the other end side (X2 side) (connection) ). In FIGS. 5 and 6, a portion where the conductor layers 42 are connected to each other is shown as a portion A. At this time, in the Y2 side A portion in the width direction (Y direction) of the rectangular substrate 10, the conductor layers 42 provided on the longitudinal direction convex portion 44 are in contact with each other (connected).

On the other hand, in the Y1 side B portion in the width direction (Y direction) of the rectangular substrate 10, the conductor layer is provided on the longitudinal direction convex portion 44. 42 are in contact with each other, but in a state in which the substrates 41 are in contact with each other. Further, in a state in which the base materials 41 are in contact with each other, the base materials 41 may be opposed to each other without being separated by a slight gap.

Next, as shown in FIG. 6, the rod-shaped jig J is used to change the opposing state of the longitudinal direction convex portion 44 in the B portion on the Y1 side. For example, in the configuration shown in Fig. 6, the jig J is lowered from the top to the bottom. Then, in the portion where the longitudinal direction convex portions 44 overlap each other, the respective longitudinal direction convex portions 44 are gradually curved as the pressing jig J is pressed, and the length in the X direction of each of the longitudinal direction convex portions 44 is gradually shortened.

When the lengthwise convex portion 44 is largely bent and the length of the longitudinal direction convex portion 44 in the X direction is greatly shortened, the longitudinal convex portion 44 on the lower side and the upper longitudinal convex portion 44 are not in contact with each other. At this time, the jig J is kept in a state of being in contact with the longitudinal convex portion 44 on the upper side. Therefore, the pressed state of the lower longitudinal direction convex portion 44 is released, and is positioned above the upper longitudinal direction convex portion 44 by the elastic restoring force. Thereby, the upper and lower positions of the overlapping longitudinal direction convex portions 44 are exchanged before and after the pressing by the jig J is completed. Further, after the vertical position of the longitudinal direction convex portion 44 is exchanged, the jig J can be further pressed to disengage the jig J from the longitudinal direction convex portion 44 that is in contact therewith, and the jig J can be returned upward.

Fig. 7 is a side cross-sectional view showing a state in which the upper and lower positions of the longitudinal direction convex portion 44 are interchanged. In addition, FIG. 8 is a top view showing a state in which the upper and lower positions of the longitudinal direction convex portion 44 are interchanged. Compared with the top view shown in FIG. 6, in the top view shown in FIG. 8, the portion surrounded by the broken line B is In the middle, the upper and lower positions of the longitudinal direction convex portion 44 are interchanged. However, in the portion surrounded by the broken line A portion, since the pressing is not performed by the jig J, the vertical position of the longitudinal direction convex portion 44 is not interchanged.

Thereby, when the vertical position of the longitudinal direction convex portion 44 in the vicinity of the broken line B portion is interchanged, the state in which the base materials 41 are in contact with each other before the interchange becomes the state in which the conductor layers 42 are in contact with each other after the interchange. Figure 9 is a side cross-sectional view showing the configuration of the vicinity of the portion A and the vicinity of the portion B in Figure 8, wherein (A) is a cross-sectional view taken along line AA, and (B) is a section taken along line BB. Figure. As shown in FIG. 9, after the upper and lower positions of the longitudinal direction convex portion 44 are interchanged, the conductor layers 42 in the broken line B portion are also in contact with each other. Further, as shown in the configuration of FIGS. 6-9, the conductor layer 42 is connected to the conductor-like layer 42 on one side surface of the substrate 10, and the conductor layer 42 and the conductor on the other side surface of the substrate 10. The thin plate-like projecting portion 44 to which the layer 42 is connected has two connecting portions between the width direction of the substrate 10 perpendicular to the longitudinal direction and the corresponding thin plate-like protruding portion 44 of the other substrate 10, and the two connections are transmitted through The two different connections in the portion are such that the conductor layers 42 on the thin plate-like projections 44 are connected in an X-shape in the width direction (Y direction).

As shown in FIG. 10, in this state, the connecting member 60 is disposed on the upper and lower sides of the contact portion of the conductor layer 42 of the longitudinal direction convex portion 44, respectively. The connecting member 60 has an insulating film layer 61, a conductor layer 62, and an adhesive layer 63, wherein the conductor layer 62 is located on a side of the insulating film layer 61 that is not in contact with the longitudinal direction convex portion 44 of the single-sided laminate 40. The adhesive layer 63 is on the surface of the insulating film layer 61 opposite to the conductor layer 62.

Pressurizing after the above connecting member 60 is disposed, thereby The connecting member 60 is crimped onto a portion where the conductor layers 42 are connected to each other. It is preferable that the pressure bonding is performed at a predetermined pressure while being heated to a predetermined temperature. Then, as shown in FIG. 11, the adhesive which constitutes the adhesive layer 63 is melted and flows out to fill the gap.

Further, as shown in FIG. 11, the gap includes a gap between the connecting member 60 and the longitudinal direction convex portion 44, a gap between the double-sided laminate 20 and the connecting member 60, and a longitudinal direction convex portion 44 and a double-sided layer. A gap between the pressure plates 20 and the like. The rectangular substrate 10 is connected to each other through the above-mentioned adhesive (adhesive layer 63) to form an intermediate product 70. The intermediate product 70 thus formed can be wound into a roll shape so that it can be used in a roll-to-roll process.

In addition, FIG. 12 is a top view showing an arrangement state of the connecting member 60, in which a portion indicated by a chain double-dashed line is the connecting member 60. The non-contact surface of the connecting member 60 that is not in contact with the conductor layer 42 may be formed as a conductor. In this case, when the plating film 90 is formed, the surface side in contact with the cathode roller as the feeding portion is a conductor, and thus it is possible to reduce the adverse effect on the production line.

Further, in the present embodiment, the intermediate product 70 is not limited to the components shown in Fig. 11, and includes the components shown in Figs. 12 to 15 which are obtained through the subsequent steps of Fig. 11.

Next, the intermediate product 70 is moved into a roll-to-roll production line, and a conductive film 80 is formed on the intermediate product 70 by a continuous manufacturing method. Fig. 13 is a side sectional view showing a state in which the electroconductive thin film 80 is formed on the intermediate product 70 of Fig. 11. At this time, it is preferable to form by direct plating treatment. The conductive film 80 is formed, but the conductive film 80 may be formed by other methods such as electroless plating. Further, not only the conductive film 80 is formed on the surface of the rectangular substrate 10, but also the conductive film 80 is formed in the interlayer connection via 50, and the conductive film 80 is also formed on the connection member 60.

Next, a plating film 90 is formed on the electroconductive film 80. Fig. 14 is a side sectional view showing a state in which the plating film 90 is formed on the electroconductive film 80 of Fig. 13. The plated film 90 can be formed in a roll-to-roll manner using, for example, a clamp-powered plating apparatus.

Next, a circuit pattern 46 is formed on the rectangular substrate 10 by metal surface lithography such as etching. Fig. 15 is a side sectional view showing a state in which the circuit pattern 46 is formed after the plating film 90 shown in Fig. 14 is formed. Further, in Fig. 15, the portion corresponding to the circuit pattern 46 is indicated by the concave shape of the conductor layer 42, but the electroplated film 90 which is actually unnecessary is also removed.

Next, the intermediate product 70 after the formation of the circuit pattern 46 is cut. Fig. 16 is a side sectional view showing a state in which the intermediate product 70 in which the circuit pattern 46 is formed is cut. In this cutting, the cutting is performed so as to cut off the longitudinal direction convex portion 44 and the longitudinal direction concave portion 45. After the above-described steps, the flexible printed circuit board P is formed.

<About Comparative Example>

As a comparative example of the flexible printed circuit board P of the above-described embodiment, a conventional method of manufacturing a flexible printed circuit board will be briefly described with reference to FIGS. 20 to 25.

First, as shown in FIG. 20, a double-sided laminate 110 having a conductor layer 112 provided on both sides of a substrate 111 is prepared, wherein the substrate 111 is a polycrystalline substrate. A flexible film and an insulating member such as an amine film, and the conductor layer 112 is a metal foil such as a copper foil. Then, a pattern is formed on the conductor layers 112 on both sides, and then the adhesive layer 120 is laminated, and then the single-sided laminate 130 in which the conductor layer 132 is provided only on one side of the substrate 131 is laminated, thereby forming a four-layer conductor layer. Then, the interlayer connection via 140 is formed by NC drilling. Thereby, the rectangular shaped substrate 100 corresponding to the rectangular substrate 10 of FIG. 1 is formed.

Next, as shown in FIG. 21, the rectangular shaped substrate 100 is connected by the connecting member 150. This step corresponds to FIG. 10 or FIG. 11 of the present embodiment. Then, a conductive film 160 is formed as shown in FIG. This step corresponds to FIG. 13 of the present embodiment. Next, a plating film 170 is formed as shown in FIG. 23, and this step corresponds to FIG. 14 of the present embodiment. Next, as shown in FIG. 24, the circuit pattern 180 is formed by conventional metal surface lithography. This step corresponds to FIG. 15 of the present embodiment. Next, as shown in FIG. 25, the flexible printed circuit board 200 is obtained by cutting away the connection portion of the rectangular substrate 100. In addition, this step corresponds to FIG. 16 of the present embodiment.

In addition, as shown in FIG. 26, the connecting member 150 has an adhesive layer 151 and a conductor layer 152. Therefore, in the comparative example, when the substrates 100 are connected to each other, two contact points are formed. In addition, since the adhesive layer 151 is formed on the connecting member 150, the area of the conductor layer 152 is restricted, resulting in an increase in the connection resistance.

<About efficacy>

According to the above-described manufacturing method of the flexible printed circuit board P and its intermediate product 70, the rectangular substrate 10 is provided with a longitudinal direction convex portion 44 having a thickness smaller than that of the other portion of the rectangular substrate 10. In addition, with the rectangular substrate 10 In the same manner, the conductor layer 42 is also provided in the longitudinal direction convex portion 44, and the lengthwise convex portion 44 and the other end side (X2 side) of the one end side (X1 side) in the longitudinal direction of the rectangular substrate 10 are also long. The direction convex portions 44 are provided to be respectively connected to different surfaces on the upper and lower sides of the rectangular substrate 10. Further, the longitudinal direction convex portion 44 of the rectangular substrate 10 on the one end side (X1 side) in the longitudinal direction and the longitudinal direction convex portion 44 of the rectangular substrate 10 on the other end side (X2 side) are disposed so as to be connected to each other by the conductor layer 42 to form The connecting portion is then fixed by the connecting member 60.

Therefore, as compared with the comparative example of FIGS. 21 to 24 described above, it is clear that the thickness of the portion where the longitudinal direction convex portions 44 are connected to each other (the conductor layers 42 are different from each other) is much smaller than the total thickness of the two rectangular substrates 10 to be joined. Thereby, damage to the cathode roller caused by the joint portion can be greatly reduced. Further, by reducing the thickness of the joint portion, the intermediate product 70 in which the joint member 60 is present is easily wound into a roll shape. Therefore, the flexible printed circuit board P can be easily manufactured by the continuous manufacturing method. Thereby, since the flexible printed circuit board P can be manufactured by moving the intermediate product 70 in a continuous process of roll-to-roll, it is possible to use a single-sided circuit board which is currently provided with a conductor layer on only one side, or in a double A production line having the same production line as that used for a double-sided circuit board having a conductor layer is used to manufacture a multilayer circuit board. Therefore, the production cost can be reduced.

Further, as described above, by manufacturing the flexible printed circuit board P by the continuous processing of the roll-to-roll method, labor saving and efficiency can be improved, and the quality is also stabilized, so that the yield can be improved. Thereby, the cost can be further reduced.

Further, in the present embodiment, by connecting the connecting member 60 to the portion where the longitudinal direction convex portions 44 are connected to each other (the conductor layers 42 are connected to each other), the thickness of the portion where the connecting member 60 is present can be greatly reduced. Thereby, the conductive film 80 or the plating film 90 can be made uniform as compared with the case where the thickness at the portion where the connecting member 60 is present is large.

Further, as described above, by crimping the connecting member 60 to the portion where the longitudinal direction convex portions 44 are connected to each other (the conductor layers 42 are connected to each other), the thickness at the portion where the connecting member 60 exists can be greatly reduced, and the intermediate product can be reduced. Concavity and convexity existing on 70. Thereby, it is possible to suppress a decrease in the lamination property of the dry film (photoresist layer) when the pattern is formed on the surface layer of the intermediate product 70.

Further, in the present embodiment, since the conductor layers 42 in the longitudinal direction convex portions 44 are directly in contact with each other, the connection resistance can be greatly reduced as compared with the comparative example of FIGS. 21 and 26, thereby facilitating uniformity. A plating film 90 is formed on the ground.

Further, in the present embodiment, a pair of longitudinal direction convex portions 44 are provided in the width direction of the rectangular substrate 10, and one longitudinal direction convex portion 44 is connected to the one-side laminate 40 (conductor layer 42) on the upper surface side, and the other The longitudinal direction convex portion 44 is connected to the single-sided laminate 40 (conductor layer 42) on the lower surface side. Since the pair of longitudinal direction convex portions 44 are provided in this manner, the upper surface side conductor layer 42 of the rectangular substrate 10 and the upper surface side conductor layer 42 and the lower surface side conductor layer 42 of the other rectangular substrate 10 adjacent thereto are electrically connected, and similarly, rectangular The lower side conductor layer 42 of the substrate 10 is electrically connected to the upper side conductor layer 42 and the lower side conductor layer 42 of the other rectangular substrate 10 adjacent thereto. Therefore, the voltages on the upper and lower sides can be made uniform, so that the conductive film 80 or the conductive film 80 can be The plating film 90 and the like become uniform.

Further, in the present embodiment, a gap portion is provided between the two longitudinal direction convex portions 44 which are arranged along the width direction (Y direction) of the rectangular substrate 10. In addition, the gap portion is set to a gap portion of a degree in which the longitudinal direction convex portions 44 are bent in the direction in which the longitudinal direction convex portions 44 are bent in the upper and lower directions, and the longitudinal direction convex portions 44 are brought into contact with each other as shown in FIGS. 7 to 9 . The longitudinal direction convex portions 44 do not interfere with each other. Therefore, the work of bringing the longitudinal direction convex portions 44 into contact with each other (the conductor layers 42) is easy, and the operability at the time of manufacturing the flexible printed circuit board P can be improved.

In addition, in the present embodiment, the laminate constituting the rectangular substrate 10 includes the double-sided laminate 20 and the single-sided laminate 40, and the double-sided laminate 20 and the single-sided laminate 40 are fixed by the adhesive layer 30, Here, the double-sided laminate 20 is provided with a conductor layer 22 on both sides of the substrate 21, and the single-sided laminate 40 is provided with the conductor layer 42 only on one side of the substrate 41, and on one end side (X1 side) and the other end The side (X2 side) is provided with a longitudinal direction convex portion 44. Therefore, a multilayer structure having a total of four conductor layers 22 and 42 can be realized.

Further, in the present embodiment, the adhesive layer 30 is provided to have a length greater than the length of the substrate 21 of the double-sided laminate 20. Moreover, the adhesive layer 30 is set to have a length smaller than a length of a portion of the one-side laminate 40 in which the longitudinal direction convex portion 44 exists, but is larger than a portion of the single-sided laminate 40 in which the longitudinal direction convex portion 44 is not present (punching) The length of the portion of the recess 45 in the longitudinal direction. Therefore, in the crimping step of the connecting member 60, the thickness of the connecting portion is reduced, so that the filling property of the dry film becomes good. Further, in the wet process, since the adhesive layer 30 is provided, it is possible to prevent the penetration of the chemical liquid.

<Modification>

Although an embodiment of the present invention has been described above, the present invention can be variously modified in addition to the above. This will be described below.

In the above embodiment, the flexible printed circuit board P and the rectangular substrate 10 which are multilayer structures in which the four conductor layers 22 and 42 are collectively described are described. However, the flexible printed circuit board P and the rectangular substrate 10 are not limited to a multilayer structure in which a total of four conductor layers are provided. For example, the flexible printed circuit board P and the rectangular substrate 10 may be a multilayer structure having a three-layer conductor layer in combination with a double-sided laminate and a single-sided laminate, or may be a multilayer structure having five or more conductor layers.

Further, in the above-described embodiment, the pair of longitudinal direction convex portions 44 are provided in the width direction (Y direction) of the rectangular substrate 10. However, the present invention is not limited to providing a pair of longitudinal direction convex portions 44 in the width direction (Y direction). For example, as shown in FIGS. 17 and 18, only one longitudinal direction convex portion 44 may be provided in the width direction (Y direction). In this case, the rectangular substrate is configured such that one (a total of two) longitudinal convex portions 44 are provided at one end side and the other end side in the longitudinal direction (X direction). In the case of such a configuration, the thickness of the portion where the longitudinal direction convex portions 44 are connected to each other (the conductor layers 42) can be made much smaller than the total thickness of the two rectangular substrates 10 to be connected, so that the connection portion can be greatly reduced. Damage caused by the cathode roller.

Further, in the above embodiment, a pair of longitudinal direction convex portions 44 are provided in the width direction (Y direction), and each of the rectangular substrates 10 is provided. The configuration in which a total of four longitudinal direction convex portions 44 are provided has been described. However, the number of the longitudinal direction convex portions 44 may be more than four. For example, in the configuration shown in Fig. 19, three longitudinal direction convex portions 44 are provided in the width direction (Y direction), so that a total of six longitudinal direction convex portions 44 are provided on each rectangular substrate 10.

Claims (5)

A manufacturing method of a flexible printed circuit board in which a plurality of substrates are connected to each other to manufacture a flexible printed circuit board, wherein a plurality of laminates are laminated in the substrate, and on one side of the substrate A conductor layer is respectively disposed on the surface and the other side surface, and the manufacturing method of the flexible printed circuit board includes a substrate forming step, a connecting step, and a fixing step, and in the substrate forming step, forming a thin plate shape a substrate of the protrusion, wherein the thin plate-like protrusion has a thickness smaller than other portions of the substrate and a conductor layer is provided on the surface, and the thin plate-like protrusion is on one end side in the longitudinal direction of the substrate And a state in which the other end side is connected to the mutually different surfaces, and is disposed on the substrate; in the connecting step, the conductor layer of the thin plate-like protrusion provided on one end side of the substrate is disposed on The conductor layer of the thin plate-like protrusion on the other end side of the other substrate is in contact to form a connecting portion; in the fixing step, by respectively The connecting portion is fixed to a connecting member on one side and the other side of the connecting portion; wherein the conductor layer is connected to the conductor layer of one side surface of the substrate The thin plate-like protrusion connected to the conductor layer on the other side surface of the substrate is corresponding to the other of the substrates in the width direction of the substrate perpendicular to the length direction There are two connecting portions between the thin plate-like protrusions, and the thin portions are made by two different connecting manners of the two connecting portions. The conductor layers on the plate-like projections are connected in an X-shape in the width direction. The method of manufacturing a flexible printed circuit board according to claim 1, wherein a gap portion is provided between the two thin plate-like protrusions arranged along the width direction of the substrate; The portion is set to a gap portion of a degree that the thin plate-like projections do not interfere with each other when the thin plate-like projections are bent to protrude from different surfaces of the substrate in the connecting step . The method of manufacturing a flexible printed circuit board according to claim 1 or 2, wherein the laminate comprises a double-sided laminate and a single-sided laminate, wherein the double-sided laminate is in each of the substrates Conductive layers are respectively provided on the surface, the single-sided laminate is provided with a conductor layer on one surface of the substrate, and at least one end side of the one-side side and the other end side of the one-side laminate in the longitudinal direction is provided There is the thin plate-like projection on which the one-side laminate is fixed by the adhesive layer on one side surface and the other side surface of the double-sided laminate, respectively. The method of manufacturing a flexible printed circuit board according to claim 3, wherein the adhesive layer is set to have a length greater than a length of the substrate of the double-sided laminate; Further, the adhesive layer is disposed to have a length smaller than a length of a portion of the single-sided laminate in which the thin plate-like protrusion exists, but larger than the thin plate-like protrusion not present in the single-sided laminate The length of the part. An intermediate product for manufacturing a flexible printed circuit board in which a plurality of substrates are connected to each other to manufacture the flexible printed circuit board, wherein a plurality of laminates are laminated in the substrate And a conductor layer is respectively disposed on one side surface and the other side surface of the substrate, wherein the intermediate product is characterized by: a thin plate-like protrusion disposed on the substrate and having a thickness smaller than the substrate The other portion is provided with a conductor layer on the surface of the thin plate-like protrusion, and the thin plate-like protrusion is connected to the mutually different surfaces at one end side and the other end side in the longitudinal direction of the substrate. a state of being disposed on the substrate; a connecting portion that transmits the conductor layer of the thin plate-like protruding portion provided on one end side of the substrate and the thin plate plate disposed at the other end side of the other substrate Forming the conductor layers of the protrusions in contact; and connecting members respectively disposed on one side and the other side of the connecting portion, and fixing the connecting portions; And the thin plate-like protrusion and the conductor layer of the conductor layer connected to the conductor layer on one side surface of the substrate are connected to the thin plate-like protrusion of the conductor layer on the other side surface of the substrate, There are two connecting portions between the thin plate-like protrusions corresponding to the other substrate in the width direction of the substrate perpendicular to the longitudinal direction, and Two different connections of the two connecting portions are such that the conductor layers on the thin plate-like projections are connected in an X-shape in the width direction.