JP2010212398A - Method of manufacturing flexible printed board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To sufficiently curve a part on which an electronic component is mounted in a flexible printed board. <P>SOLUTION: A method of manufacturing a flexible printed board is equipped with steps of: forming a peeling layer 52 on one surface 51 of a temporary base material 50; forming a metal layer on a surface of the peeling layer, a step of arranging a driving circuit 34 on one surface of the temporary base material and connecting the driving circuit with the metal layer; applying a material so as to cover the one surface of the temporary base material to form a flexible base material; and removing the temporary base material and the peeling layer. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

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

  2. Description of the Related Art Conventionally, a technique for configuring a flexible printed circuit board by mounting an electronic component such as an IC chip on the upper surface of a flexible base material is known (see, for example, Patent Document 1).

Japanese Patent Laid-Open No. 06-216532

However, the flexible printed circuit board disclosed in Patent Document 1 has a problem that a portion where an electronic component is mounted is difficult to bend because its thickness is larger than that of other portions.
In view of the above circumstances, an object of the present invention is to solve the problem of sufficiently bending a portion on which an electronic component is mounted in a flexible printed board.

In order to solve the above problems, a method for producing a flexible printed board according to the present invention includes a step of forming a release layer on one surface of a temporary base material, and a step of forming a metal layer on the surface of the release layer. a step of on one side of the temporary substrate the electronic component with disposing an electronic component connected to the metal layer, after the step of connecting the electronic component to the metal layer covers the one surface of the temporary substrate The method includes a step of forming a flexible base material that houses at least a part of the electronic component, and a step of removing the temporary base material and the release layer after the step of forming the base material.

  According to this manufacturing method, it is possible to manufacture a flexible printed circuit board in which at least a part of the electronic component is built in (stored in the base material) in the flexible base material. And in the flexible printed circuit board manufactured by this manufacturing method, since at least a part of the electronic component is built in the flexible base material, the thickness of the portion where the electronic component is arranged in the flexible printed circuit board is This is smaller than the aspect in which the electronic component is mounted on the upper surface of the flexible base material. Therefore, the flexible printed circuit board manufactured by this manufacturing method can greatly bend the portion where the electronic component is arranged, compared to the flexible printed circuit board on which the electronic component is mounted on the upper surface of the flexible base material. There is an advantage.

  As a specific aspect of the method for producing a flexible printed circuit board according to the present invention, in the step of forming the metal layer, a first metal layer (for example, FIG. A first layer 36a) shown in FIG. 4 and a second metal layer (for example, the wiring 38 shown in FIG. 4) arranged away from the first metal layer are formed, and the temporary substrate and the release layer are removed. Thereafter, the method further includes a step of covering the first metal layer with a third metal layer (for example, the metal layer 36b shown in FIG. 5) and covering the second metal layer with an insulating material.

  In the step of forming the flexible substrate, the flexible substrate is preferably formed such that the upper surface of the electronic component is exposed from the flexible substrate. According to this aspect, there is an advantage that the heat dissipation amount of the electronic component can be increased as compared with the aspect in which the electronic component is covered (wrapped) with the base material.

  In the step of forming the flexible substrate, the flexible substrate may be formed so as to cover the upper surface of the electronic component. According to this aspect, there is an advantage that damage to the electronic component can be suppressed even when an external impact is applied to the flexible printed circuit board.

Further, as a manufacturing method of a flexible printed circuit board according to the present invention, forming a metal layer on one surface of the temporary substrate, a flexible substrate which will covering one surface and metal layer of the temporary substrate Forming the recess, forming the recess by partially removing the flexible base material, exposing the inner part of the recess in the metal layer, housing the electronic component in the recess, and A step of connecting the electronic component and the metal layer; a step of housing the electronic component in the recess and connecting the metal component to the metal layer; and then filling the recess with a flexible material; and After the step of filling, it is possible to adopt a mode including a step of removing the temporary base material. Even with this manufacturing method, it is possible to manufacture a flexible printed board in which at least a part of an electronic component is built in a flexible base material.

Furthermore, as a method for producing a flexible printed board according to the present invention, a step of forming a metal layer on one surface of a flexible first base material (for example, the base material 70 shown in FIG. 10), and the first base material forming a second substrate of the flexible Let covering one surface and metal layer (e.g., substrate 32 shown in FIG. 10), to form a recess of the second substrate is partially removed The step of exposing the portion of the metal layer that overlaps the recess, the step of accommodating the electronic component in the recess, the step of connecting the electronic component and the metal layer, the step of accommodating the electronic component in the recess and connecting to the metal layer Then, after the step of filling the concave portion with the flexible material and the step of filling the concave portion with the flexible material, the portion of the metal layer connected to the wiring of the other substrate is the first base material. And an exposing step. Even with this manufacturing method, it is possible to manufacture a flexible printed board in which at least a part of an electronic component is built in a flexible base material.

  The above-described aspect further includes a step of partially removing the thickness direction of the first base material. Further, in the step of forming the metal layer, on one surface of the first base material, a first metal layer (for example, the first layer 36a shown in FIG. 10) for connecting to the wiring of the other substrate, A step of forming a second metal layer (for example, the wiring 38 shown in FIG. 10) disposed apart from the metal layer and exposing a portion of the metal layer connected to the wiring of another substrate from the first base material. The first metal layer is exposed from the first substrate.

  In the step of filling the recess with the flexible material, the upper surface of the electronic component is preferably exposed from the flexible material filled in the recess. According to this aspect, there is an advantage that the heat dissipation amount of the electronic component can be increased as compared with the aspect in which the electronic component is covered (wrapped) with the base material.

  Further, in the step of filling the recess with the flexible material, the upper surface of the electronic component can be covered with the flexible material filled in the recess. According to this aspect, there is an advantage that damage to the electronic component can be suppressed even when an external impact is applied to the flexible printed circuit board.

1 is a plan view of an electro-optical device according to a first embodiment of the invention. FIG. 3 is a cross-sectional view of the electro-optical device according to the embodiment. It is a figure which shows a mode when a flexible printed circuit board is connected. It is a figure which shows the 1st manufacturing method which concerns on the same embodiment. It is a figure which shows the 1st manufacturing method which concerns on the same embodiment. It is a figure showing the 2nd manufacturing method concerning the embodiment. It is a figure showing the 2nd manufacturing method concerning the embodiment. It is a figure showing the 2nd manufacturing method concerning the embodiment. FIG. 6 is a cross-sectional view of an electro-optical device according to a second embodiment of the invention. It is a figure which shows the manufacturing method of the flexible printed circuit board concerning the embodiment. It is a figure which shows the manufacturing method of the flexible printed circuit board concerning the embodiment. FIG. 10 is a cross-sectional view of an electro-optical device according to a modified example of the invention. FIG. 10 is a cross-sectional view of an electro-optical device according to a modified example of the invention. FIG. 10 is a cross-sectional view of an electro-optical device according to a modified example of the invention. It is sectional drawing which shows a comparative structure.

<A: First Embodiment>
<A-1: Configuration>
FIG. 1 is a plan view of an electro-optical device 10 according to the first embodiment of the present invention. 2 is a cross-sectional view taken along line AA in FIG. The electro-optical device 10 is a device that is employed in various electronic devices as a means for displaying an image, and includes a display panel 20 and a flexible printed board 30.

  The display panel 20 includes a first substrate 22 and a second substrate 24 disposed to face the first substrate 22. The second substrate 24 is bonded to the first substrate 22 via a sealing agent 26 applied to the periphery thereof, and a liquid crystal Lq is sealed between the two substrates. A common electrode common to each electro-optical element P is formed on the surface of the second substrate 24 facing the first substrate 22. On the surface of the first substrate 22 facing the second substrate 24, pixel electrodes, thin film transistors, signal lines 11 and the like of each electro-optical element P are formed. In the present embodiment, each electro-optical element P includes a pixel electrode and a common electrode, and a liquid crystal Lq interposed therebetween.

  Driving signals for driving each electro-optical element P (for example, a selection signal for selecting each electro-optical element P, a data signal for designating the gradation of each electro-optical element P, etc.) are supplied to each. The plurality of signal lines 11 are formed on the first substrate 22. Each signal line 11 extends toward the periphery of the first substrate 22. A flexible printed circuit board 30 is disposed in a region of the surface of the first substrate 22 that protrudes from the periphery of the second substrate 24.

  The flexible printed circuit board 30 includes a flexible (bendable) base material 32, a drive circuit 34 built in the base material 32, and an electrode 36 connected to the drive circuit 34. The drive circuit 34 is an IC chip and is a means for outputting a drive signal. In the present embodiment, the thickness of the drive circuit 34 is set to 100 μm or less. For this reason, the drive circuit 34 has a certain degree of flexibility.

  The drive circuit 34 is accommodated in the recess D of the base material 32, and the upper surface E is exposed from the base material 32. Furthermore, the upper surface E of the drive circuit 34 and the upper surface F of the base material 32 are continuously flat. Further, as shown in FIG. 2, the drive circuit 34 is connected to the electrode 36 via the first bump (protruding spherical electrode) B1, and is connected to the wiring 38 via the second bump B2. The wiring 38 is covered with a solder resist 39 made of an insulating material. Further, the drive circuit 34 is arranged so that a part thereof overlaps the surface of the display panel 20. More specifically, the drive circuit 34 is arranged so that a part thereof overlaps with the signal line 11 formed on the surface of the first substrate 22 of the display panel 20 when viewed from the vertical direction of the flexible printed circuit board 30. Yes.

  As shown in FIG. 2, the electrode 36 is formed on the lower surface G opposite to the upper surface F of the base material 32 and is disposed so as to face the signal line 11, with the anisotropic conductive film 40 interposed therebetween. Connected to the signal line 11. In the present embodiment, the electrode 36 includes a first layer 36a formed of a metal such as copper, and a metal layer 36b that covers the first layer 36a and is formed of a metal such as gold. An anisotropic conductive film 40 is interposed between the metal layer 36b and the signal line 11 to connect them. The anisotropic conductive film 40 is an adhesive made by mixing conductive particles such as nickel and solder with an adhesive resin.

  As shown in FIG. 3, when the flexible printed circuit board 30 and the display panel 20 are connected, a flexible substrate with an anisotropic conductive film 40 interposed between the metal layer 36b and the signal line 11 is used. A region of the surface F of the material 32 that overlaps the first substrate 22 (signal line 11) as viewed from the vertical direction of the base material 32 is pressed in the Z direction by a bonding tool 400 for applying heat and pressure. Thereby, the conductive particles interposed between the metal layer 36 b and the signal line 11 are crushed, and the crushed conductive particles connect the metal layer 36 b and the signal line 11. As described above, the drive circuit 34 is connected to the signal line 11 through the electrode 36. The drive signal output from the drive circuit 34 is supplied to the signal line 11 via the electrode 36.

  In the present embodiment, the flexible printed circuit board 30 is disposed so that a part of the drive circuit 34 overlaps the surface (the signal line 11) of the first substrate 22 when viewed from the vertical direction of the circuit board 30. As shown in FIG. 5, a part of the drive circuit 34 overlaps the pressing surface Pr of the bonding tool 400 when viewed from the vertical direction of the substrate 30. However, in the present embodiment, the drive circuit 34 is built in the base material 32, and the upper surface E of the drive circuit 34 and the upper surface F of the base material 32 are continuously flat surfaces. Even if a portion of the bonding tool is disposed so as to overlap the surface of the first substrate 22, the pressing surface Pr of the bonding tool is in close contact with the region of the surface F of the base material 32 that overlaps the first substrate 22. Therefore, since the said area | region is pressed uniformly by the bonding tool 400, sufficient adhesiveness can be acquired. Then, by arranging a part of the drive circuit 34 so as to overlap the surface of the first substrate 22 (the signal line 11), the resistance value of the current path from the drive circuit 34 to the signal line 11 via the electrode 36 is reduced. There is an advantage that it can be reduced.

  FIG. 15 is a cross-sectional view (corresponding to FIG. 2) of an aspect in which the drive circuit 34 is mounted on the upper surface F of the flexible base material 32 (hereinafter referred to as “comparative”). In the configuration shown in FIG. 15, the portion of the flexible printed circuit board 30 on which the drive circuit 34 is mounted has a problem that it is difficult to bend because the thickness thereof is larger than the other portions. On the other hand, according to this embodiment, since the drive circuit 34 is built in the flexible base material 32, the drive circuit 34 does not protrude from the surface F of the base material 32. Therefore, the thickness of the portion of the flexible printed board 30 where the drive circuit 34 is disposed is smaller than the configuration shown in FIG. For this reason, there exists an advantage that the part in which the drive circuit 34 is arrange | positioned among the flexible printed circuit boards 30 can be largely bent compared with the structure of FIG. That is, according to the present embodiment, the portion of the flexible printed circuit board on which the drive circuit 34 is mounted is greatly bent, and the resistance value of the path from the drive circuit 34 to the signal line 11 formed on another substrate is set. There is an advantage that both can be achieved.

<A-2: Manufacturing method>
Next, a method for manufacturing the flexible printed circuit board 30 according to this embodiment will be described. Initially, the 1st manufacturing method of the flexible printed circuit board 30 which concerns on this embodiment is demonstrated, referring FIG. 4 and FIG.

(1) 1st manufacturing method First, the peeling layer 52 is formed in the one surface 51 of the temporary base material 50 (process P1 of FIG. 4). More specifically, after applying a fluororesin such as polytetrafluoroethylene, tetrafluoroethylene, hexafluoroethylene copolymer or the like on the surface 51 of the temporary base material 50 made of polyimide, heat treatment is performed so that the fluorine The resin is cured. Thereby, the peeling layer 52 is formed on the surface 51 of the temporary base material 50.

  Next, a metal layer is formed on the surface of the release layer 52 (step P2 in FIG. 4). More specifically, the first layer 36 a of the electrode 36 and the wiring 38 made of a metal common to the first layer 36 a are formed on the surface of the release layer 52. As described above, the first layer 36 a (electrode 36) is a metal layer for connecting to the signal line 11 formed on the surface of the first substrate 22 of the display panel 20. The wiring 38 is a metal layer formed at a position away from the first layer 36a. The first layer 36a and the wiring 38 are made of copper.

  In addition, the method of forming a metal layer on the surface of the peeling layer 52 is arbitrary, For example, an additive method, a subtract method, etc. can be utilized. In addition, when a metal layer is laminated (bonded) on the surface of the release layer 52, the fluororesin that is the material of the release layer 52 is not completely cured (half-cured) and the fluororesin is adhesive. It is preferable that the metal layer is bonded in a state of having, and then the fluororesin is completely cured. Moreover, it can also be set as the aspect of preparing the base material which uses a fluororesin as a material instead of the temporary base material 50 which consists of polyimides, and forming a metal layer directly on the one surface of the said base material.

  Next, an electronic component (drive circuit 34) is disposed on one surface 51 of the temporary base material 50, and the electronic component is connected to a metal layer formed on the surface of the release layer 52. More specifically, it is as follows. First, the drive circuit 34 in which the first bump B1 for connecting to the first layer 36a and the second bump B2 for connecting to the wiring 38 are provided on one surface (lower surface) H is the first bump B1. And the surface (upper surface) E opposite to the second bump B2 is disposed at a predetermined position in a state of being vacuum-sucked to the pressing surface I of the bonding tool 500 (step P3 in FIG. 4). The predetermined position means a position where the first bump B1 faces the first layer 36a on the peeling layer 52 and the second bump B2 faces the wiring 38 on the peeling layer 52. Subsequently, the first bump B1 is brought into contact with the first layer 36a and the second bump B2 is moved by moving the driving circuit 34 vacuum-adsorbed to the bonding tool 500 to the positive side in the Z direction shown in FIG. It is made to contact with the wiring 38 (process P4 of FIG. 4). Then, the upper surface E of the drive circuit 34 is pressed to the positive side in the Z direction shown in FIG. 4 by the bonding tool 500 (process P5 in FIG. 4). As a result, the first bump B1 is pressure-bonded to the first layer 36a and the two are joined. Similarly, the second bump B2 is pressure-bonded to the wiring 38 and joined together.

  The thickness of the drive circuit 34 (the size in the Z direction shown in FIG. 4) is set to 100 μm or less. However, when the flexible printed circuit board 30 is bent, the drive circuit 34 is bent without being broken. The thickness is preferably 50 μm or less. In order to facilitate handling of the drive circuit 34 when connecting the drive circuit 34 to the metal layer, the thickness of the drive circuit 34 is preferably 20 μm or more.

Next, the flexible base material 32 that covers one surface 51 of the temporary base material 50 and accommodates at least a part of the drive circuit 34 is formed (step P6 in FIG. 5). More specifically, it is as follows. First, a liquid polyimide precursor is applied on the surfaces of the release layer 52 and the metal layers (36a, 38) so as to cover one surface 51 of the temporary substrate 50. At this time, the side surface of the drive circuit 34 is covered with the polyimide precursor over the entire circumference, while the upper surface E is exposed without being covered with the polyimide precursor. After apply | coating a polyimide precursor, heat processing are performed and the said polyimide precursor is hardened. Thereby, the flexible base material 32 made of polyimide is formed. The drive circuit 34 is accommodated in the recess D of the flexible base material 32, and the upper surface E of the drive circuit 34 and the upper surface F of the base material 32 are continuously flat.

  In addition, the application | coating method of a polyimide precursor is arbitrary and should just be able to apply | coat with uniform thickness. For example, a casting method, a roller transfer method, a dispensing method, or the like can be used.

  Next, the temporary base material 50 and the peeling layer 52 are removed (process P7 in FIG. 5). Since the release layer 52 is formed of a material from which the metal layer is easily peeled off, it is easy to peel off the temporary substrate 50 and the release layer 52 from the metal layer. After removing the temporary base material 50 and the release layer 52, the exposed first layer 36a is covered with the metal layer 36b, and the wiring 38 is covered with the solder resist 39 (step P8 in FIG. 5). The above is the first manufacturing method of the flexible printed circuit board 30 according to the present embodiment.

(2) Second Manufacturing Method Next, a second manufacturing method of the flexible printed circuit board 30 according to the present embodiment will be described with reference to FIGS. First, a metal layer is formed on one surface 51 of the temporary base material 50 (step Q1 in FIG. 6). More specifically, the first layer 36 a and the wiring 38 are formed on the surface 51 of the temporary base material 50 made of polyimide. The method for forming the metal layer on the surface 51 of the temporary substrate 50 is arbitrary, and for example, an additive method, a subtract method, or the like can be used.

Next, the flexible base material 32 that covers the surface 51 of the temporary base material 50 and the metal layer is formed (step Q2 in FIG. 6). More specifically, after applying a liquid polyimide precursor on the surface 51 of the temporary substrate 50 and the surface of the metal layer, the polyimide precursor is cured by heat treatment to cure the polyimide precursor. The base material 32 is formed. In addition, the application | coating method of a polyimide precursor is arbitrary and should just be able to apply | coat with uniform thickness.

  Next, the base material 32 is partially removed to form the recess 54, and the portion of the metal layer inside the recess 54 is exposed. More specifically, it is as follows. First, a region other than the region where the concave portion 54 is formed on the surface 55 opposite to the metal layer of the substrate 32 is covered with the etching resist 60 (step Q3 in FIG. 6). Subsequently, the region of the surface 55 of the base material 32 that is not covered with the etching resist 60 is etched to form the concave portion 54, and the portion of the metal layer inside the concave portion 54 is exposed (step of FIG. 6). Q4). Thereafter, the etching resist 60 is removed (step Q5 in FIG. 6).

  Next, the drive circuit 34 is accommodated in the recess 54 and connected to the metal layer. More specifically, it is as follows. First, the drive circuit 34 is disposed at a predetermined position with the upper surface E being vacuum-sucked by the pressing surface I of the bonding tool 500 (step Q6 in FIG. 7). Subsequently, the first bump B1 is brought into contact with the first layer 36a and the second bump B2 is moved by moving the driving circuit 34 vacuum-adsorbed to the bonding tool 500 to the positive side in the Z direction shown in FIG. The wiring 38 is brought into contact (step Q7 in FIG. 7). Then, the upper surface E of the drive circuit 34 is pressed to the positive side in the Z direction shown in FIG. 4 by the bonding tool 500 (step Q8 in FIG. 7). Accordingly, the first bump B1 is bonded to the first layer 36a, and the second bump B2 is bonded to the wiring 38. In addition, as for the thickness (size in the Z direction) of the base material 32, the position in the Z direction of the upper surface E of the drive circuit 34 in the state connected to the metal layer is the same as the position in the Z direction of the upper surface F of the base material 32. Is set to such a value.

  Next, the recess 54 is filled with a flexible material (step Q9 in FIG. 7). More specifically, it is as follows. First, the concave portion 54 is filled with a liquid polyimide precursor. At this time, the side surface of the drive circuit 34 is covered with the polyimide precursor, while the upper surface E is exposed without being covered with the polyimide precursor. After apply | coating a polyimide precursor, heat processing are performed and the said polyimide precursor is hardened. Thereby, the polyimide filled in the concave portion 54 is integrated with the base material 32, and the drive circuit 34 is accommodated in the concave portion D of the base material 32. The upper surface E of the drive circuit 34 and the upper surface F of the base material 32 are continuously flat.

  Next, the temporary base material 50 is removed to expose the metal layer (step Q10 in FIG. 8). Thereafter, the first layer 36a is covered with the metal layer 36b, and the wiring 38 is covered with the solder resist 39 (step Q11 in FIG. 8). The above is the 2nd manufacturing method of the flexible printed circuit board 30 concerning this embodiment.

  In the second manufacturing method described above, the metal layer is directly formed on one surface 51 of the temporary base material 50. However, the present invention is not limited to this, and the temporary base material is similar to the first manufacturing method described above. Alternatively, the peeling layer 52 may be formed on one surface 51 of the metal 50 and the metal layer may be formed on the peeling layer 52. According to this aspect, there is an advantage that it is easy to remove the temporary base material 50 in the process Q10.

<B: Second Embodiment>
<B-1: Configuration>
Next, an electro-optical device 10 according to a second embodiment of the invention will be described. FIG. 9 is a cross-sectional view (corresponding to FIG. 2) of the electro-optical device 10 according to the present embodiment. As shown in FIG. 9, the wiring 38 formed on the lower surface G of the flexible base material 32 is not covered with the solder resist 39 but covered with the flexible second base material 70. Different from the first embodiment described above. In the present embodiment, the second base material 70 is formed of the same material as that of the flexible base material 32. Since the other configuration is the same as that of the first embodiment, the description of the overlapping parts is omitted.

<B-2: Manufacturing method>
Next, a method for manufacturing the flexible printed circuit board 30 according to the second embodiment will be described with reference to FIGS. 10 and 11. First, a metal layer is formed on one surface 71 of the flexible second base material 70 (step R1 in FIG. 10). More specifically, the first layer 36a and the wiring 38 are formed on the surface 71 of the second base material 70 made of polyimide.

Then, the flexible base material 32 which covers the surface 71 of the 2nd base material 70 and a metal layer is formed (process R2 of FIG. 10). More specifically, after applying a liquid polyimide precursor on the surface 71 of the second base material 70 and the surface of the metal layer, heat treatment is performed to cure the polyimide precursor. Thereby, the flexible base material 32 made of polyimide is formed.

  Next, the base material 32 is partially removed to form a recess 54 for accommodating the drive circuit 34, and a portion of the metal layer that overlaps the recess 54 is exposed. More specifically, it is as follows. First, a region other than the region where the concave portion 54 is formed on the surface 55 opposite to the metal layer of the substrate 32 is covered with the etching resist 60 (step R3 in FIG. 10). Subsequently, a region of the surface 55 of the base material 32 that is not covered with the etching resist 60 is etched to form a recess 54, and a portion of the metal layer inside the recess 54 is exposed (step of FIG. 10). R4). Next, the thickness direction (Z direction in FIG. 10) of the second base material 70 is partially etched to reduce the thickness of the second base material 70 (step R5 in FIG. 10). The thickness of the 2nd base material 70 should just be a value (5-20 micrometers) of the grade which can hold | maintain the metal layer formed in the surface 71. FIG.

  In the present embodiment, since the base material 32 and the second base material 70 are formed of a common material (polyimide), the process R4 and the process R5 can be performed simultaneously. Further, step R5 can be omitted. After step R5 in FIG. 10 is completed, the etching resist 60 is removed (step R6 in FIG. 10).

  Next, the drive circuit 34 is accommodated in the recess 54 and connected to the metal layer (step R7 in FIG. 11). Since this content is the same as the process Q6-the process Q8 in the 2nd manufacturing method of 1st Embodiment, detailed description is abbreviate | omitted.

  Subsequently, the concave portion 54 is filled with a flexible material (step R8 in FIG. 11). Since this content is the same as that of process Q9 in the 2nd manufacturing method of 1st Embodiment, detailed description is abbreviate | omitted.

  Next, the part connected to the wiring of another board | substrate among metal layers is exposed from the 2nd base material 70 (process R9 of FIG. 11). More specifically, the first layer 36 a is exposed from the second base material 70 by partially etching the second base material 70. The above is the manufacturing method of the flexible printed circuit board 30 according to the present embodiment.

<C: Modification>
The present invention is not limited to the above-described embodiments, and for example, the following modifications are possible. Also, two or more of the modifications shown below can be combined.

(1) Modification 1
In each of the above-described embodiments, a mode in which the upper surface E of the drive circuit 34 incorporated in the flexible base material 32 is exposed from the base material 32 is illustrated, but the present invention is not limited to this. As shown in FIG. 4, the upper surface E of the drive circuit 34 may be covered with the base material 32. According to the mode of FIG. 12, there is an advantage that damage to the drive circuit 34 can be suppressed even when an external impact is applied to the flexible printed circuit board 30. On the other hand, in each of the above-described embodiments, since the upper surface E of the drive circuit 34 is exposed from the base material 32, the heat of the drive circuit 34 can easily escape to the outside. Therefore, there is an advantage that the amount of heat radiation from the drive circuit 34 to the outside can be increased as compared with the aspect in which the upper surface E of the drive circuit 34 is covered with the base material 32.

  For example, as illustrated in FIG. 13, the position of the upper surface E of the drive circuit 34 may be lower than the position of the upper surface F of the substrate 32. Furthermore, as shown in FIG. 14, the position of the upper surface E of the drive circuit 34 may be higher than the position of the upper surface F of the substrate 32. In short, it is sufficient that at least a part of the drive circuit 34 in the thickness direction is accommodated in the base material 32. The thickness (size in the Z direction) of the portion of the flexible printed circuit board 30 on which the drive circuit 34 is mounted is determined by accommodating at least a part of the drive circuit 34 in the thickness direction inside the base material 32. Compared to the proportionality shown in FIG. Therefore, the specific effect that the portion of the flexible printed board 30 on which the drive circuit 34 is mounted can be sufficiently curved as compared with the comparative example shown in FIG.

(2) Modification 2
In each of the above-described embodiments, the mode in which the flexible printed circuit board 30 is connected to the display panel 20 is illustrated. However, the substrate to which the flexible printed circuit board 30 is connected is not limited to the display panel 20, and wiring is formed on the surface. Any substrate may be used. For example, the flexible printed circuit board 30 may be connected to a PCB (Printed Circuit Board). In short, as a form of the present invention, it comprises an electronic component built in a flexible base material, a flexible printed board including an electrode connected to the electronic component, and a substrate on which a wiring is formed, The flexible printed board may be an electronic device having a configuration in which at least a part of the electronic component is disposed so as to overlap the surface of the board, and the electrode and the wiring are connected. Moreover, the kind of electronic component is arbitrary. The electronic component may be, for example, an IC chip or a circuit element such as a capacitor.

(3) Modification 3
In each of the above-described embodiments, a mode in which the drive circuit 34 is built in the base material 32 is illustrated. However, for example, the drive circuit 34 is mounted on the display panel 20 (COG mounting), so A control circuit that outputs data to the drive circuit 34 may be built in the base material 32. In this aspect, the control circuit that outputs the synchronization signal and the gradation data to the drive circuit 34 corresponds to the “electronic component”. Alternatively, the driving circuit 34 and the control circuit may be mounted on the display panel 20, and a power supply circuit that supplies a power supply potential to the driving circuit 34 and the control circuit may be built in the base material 32. In this aspect, the power supply circuit that supplies the power supply potential to the drive circuit 34 and the control circuit corresponds to the “electronic component”.

DESCRIPTION OF SYMBOLS 10 ... Electro-optical device, 11 ... Signal line, 20 ... Display panel, 22 ... 1st board | substrate, 24 ... 2nd board | substrate, 26 ... Sealing material, 30 ... Flexible printed circuit board, 32 ... Base 34, drive circuit, 36, electrode, 38, wiring, 39, solder resist, 40, anisotropic conductive film, 50, temporary substrate, 52, release layer, 54, recess , 60... Etching resist, 70... Second substrate, 400, 500... Bonding tool, B.

Claims (10)

Forming a release layer on one surface of the temporary substrate;
Forming a metal layer on the surface of the release layer;
Arranging an electronic component on the one surface of the temporary base and connecting the electronic component to the metal layer;
After the step of connecting the electronic component to the metal layer, forming a flexible base material that covers the one surface of the temporary base material and accommodates at least a part of the electronic component ;
After the step of forming the substrate, the step of removing the temporary substrate and the release layer,
A method for producing a flexible printed circuit board. In the step of forming the metal layer, on the surface of the release layer, a first metal layer for connecting to wiring of another substrate and a second metal layer disposed apart from the first metal layer And formed,
After the step of removing the temporary base material and the release layer, the method further comprises a step of covering the first metal layer with a third metal layer and covering the second metal layer with an insulating material.
The manufacturing method of the flexible printed circuit board of Claim 1. In the step of forming the flexible substrate, the flexible substrate is formed such that an upper surface of the electronic component is exposed from the flexible substrate.
The manufacturing method of the flexible printed circuit board of Claim 1 or Claim 2. In the step of forming the flexible substrate, the flexible substrate is formed so as to cover an upper surface of the electronic component.
The manufacturing method of the flexible printed circuit board of Claim 1 or Claim 2. Forming a metal layer on one surface of the temporary substrate;
And forming the one surface and the metal layer covering it flexible base material of the temporary substrate,
Removing the base material partially to form a recess, and exposing a portion of the metal layer inside the recess; and
Storing the electronic component in the recess, and connecting the electronic component and the metal layer;
Filling the recess with a material having flexibility after accommodating the electronic component in the recess and connecting to the metal layer;
A step of removing the temporary base material after the step of filling the concave portion with a material having flexibility,
A method for producing a flexible printed circuit board. Forming a metal layer on one surface of the flexible first substrate;
Forming a second substrate of the flexible covering the one surface and the metal layer of the first substrate,
Removing the second base material partially to form a recess, and exposing a portion of the metal layer that overlaps the recess;
Storing the electronic component in the recess, and connecting the electronic component and the metal layer;
Filling the recess with a material having flexibility after accommodating the electronic component in the recess and connecting to the metal layer;
After the step of filling the concave portion with a flexible material, the step of exposing the portion of the metal layer connected to the wiring of another substrate from the first base material,
A method for producing a flexible printed circuit board. Further comprising the step of partially removing the thickness direction of the first substrate.
The manufacturing method of the flexible printed circuit board of Claim 6. In the step of forming the metal layer, the first metal layer for connecting to the wiring of the other substrate and the first metal layer are disposed on one surface of the first base material apart from each other. Two metal layers are formed,
In the step of exposing a portion of the metal layer connected to the wiring of another substrate from the first base material, the first metal layer is exposed from the first base material,
The manufacturing method of the flexible printed circuit board of Claim 6 or Claim 7. In the step of filling the concave portion with a flexible material, the upper surface of the electronic component is exposed from the flexible material filled in the concave portion.
The manufacturing method of the flexible printed circuit board in any one of Claims 6-8. In the step of filling the concave portion with a flexible material, the upper surface of the electronic component is covered with the flexible material filled in the concave portion.
The manufacturing method of the flexible printed circuit board in any one of Claims 6-8.

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