Manufacturing method of circuit-embedded substrate

Abstract

To provide a manufacturing method for a circuit embedded board, in which a yield can be improved by increasing positioning accuracy between a circuit and an electrode pad.SOLUTION: A manufacturing method includes the steps of: preparing a film; disposing two electrode pads along a first direction on the film; embedding, in the film, a circuit formed of a conductive wire and having a function part in an arbitrary pattern, two wiring parts drawn out from both ends thereof, and two end parts extending in the first direction from the wiring parts so as to partially overlap with the electrode pads, using an ultrasonic welder; and connecting the electrode pads and the conductive wire thereon. Each end of the two end parts is disposed on the same side with respect to the two electrode pads in plan view. The ultrasonic welder includes a horn that embeds the conductive wire in the film by melting a contact surface of the film with the conductive wire with ultrasonic vibration, and the conductive wire drawn out through the inside. The two end parts have a length that absorbs displacement between the electrode pad and the circuit in the first direction.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing a circuit-embedded substrate. [Background technology]

[0002] A film heater or the like is known in which a single thin metal wire is embedded in a film in an arbitrary pattern (see, for example, Patent Document 1). Referring to Fig. 12, such a film heater 100 includes a film 200, a rectangular first electrode pad 500 and a second electrode pad 600 arranged parallel to each other and spaced apart along the Y direction on the periphery of the film 200, and a circuit 400 made of a single thin metal wire 300 embedded in the film 200. The circuit 400 has a heater section 450 having an arbitrary pattern, a first wiring section 430 and a second wiring section 440 drawn out from both ends of the heater section 450, and a first end section 410 and a second end section 420 extending from the first wiring section 430 and the second wiring section 440 in the opposite direction from the heater section 450 (the +X direction in the figure) and overlapping with a first electrode pad 500 and a second electrode pad 600, respectively. The circuit 400 is embedded by applying ultrasonic vibrations using an ultrasonic welding machine to melt the contact surface between the film 200 and the thin metal wires 300. For example, the circuit 400 can be embedded in the film 200 in the following order: first end section 410, first wiring section 430, heater section 450, second wiring section 440, and second end section 420.

[0003] The first end 410 and the second end 420 straddle the first electrode pad 500 and the second electrode pad 600, respectively, in the X direction. The upper surfaces of the first electrode pad 500 and the second electrode pad 600 are electrically connected to the thin metal wires 300 that contact the upper surfaces of the first end 410 and the second end 420. When a voltage is applied to the first electrode pad 500 and the second electrode pad 600, a current is generated in the circuit 400, and the heater section 450 generates heat. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2022-066706 Summary of the Invention [Problem to be solved by the invention]

[0005] In the conventional manufacturing method of the film heater 100, the electrode pads 500, 600 are first placed on the film 200, and the corners of the film 200 are then placed against a jig (not shown). Then, the thin metal wires 300 are embedded in the film 200 so that the first end 410 and the second end 420 overlap the electrode pads 500, 600. Because the placement of the electrode pads 500, 600 and the embedding of the thin metal wires 300 are separate processes, the following misalignments occur: (1) misalignment of the electrode pads, (2) misalignment of the embedded thin metal wires, and (3) misalignment of the electrode pads and the embedded thin metal wires. In this manufacturing method, if the placement locations of the electrode pads 500, 600 are misaligned in the +Y direction in FIG. 13(a), for example, the embedded position of the thin metal wires 300 will be relatively misaligned in the -Y direction in FIG. 13(a). In other words, in the conventional manufacturing method, it is difficult to align the electrode pads 500, 600 with the circuit 400, and therefore there is a problem that it is difficult to increase the yield rate.

[0006] The present invention has been made to solve the above-mentioned problems, and aims to provide a method for manufacturing a circuit-embedded substrate that can improve the yield rate by increasing the alignment accuracy between the circuit and the electrode pads. [Means for solving the problem]

[0007] The first invention to achieve the above object is: a preparation step of preparing a film; an arrangement step of arranging first electrode pads and second electrode pads parallel to each other at intervals along a first direction on a peripheral edge portion of a first main surface of the film; a circuit forming process for forming a circuit having: a functional section arranged on a first main surface of the film, the functional section being made of conductive wires with insulating coating of thin metal wires and having an arbitrary pattern; a first wiring section drawn out from one of both ends of the functional section to the outside of the functional section; a second wiring section drawn out from the other of both ends of the functional section to the outside of the functional section; a first end section extending from the first wiring section in a first direction so as to overlap the first electrode pads and the second electrode pads; and a second end section extending from the second wiring section along the first end section so as to overlap the first electrode pads and the second electrode pads; and a first connecting step of removing the insulating coating of the conductive wire located on the first electrode pad and electrically connecting the exposed thin metal wire and the first electrode pad; a second connecting step of removing the insulating coating of the conductive wire located on the second electrode pad and electrically connecting the exposed thin metal wire to the second electrode pad; one end of the first end portion connected to the first wiring portion and one end of the second end portion connected to the second wiring portion are arranged on the same side of the first electrode pad and the second electrode pad in a plan view; The ultrasonic welding machine has a horn that applies ultrasonic vibrations to melt the contact surface of the film with the conductive wire and embed the conductive wire in the first main surface of the film, and a conductive wire that passes through the inside of the horn and is continuously drawn out from the tip of the horn onto the first main surface of the film, In this method for manufacturing a circuit-embedded substrate, the first end and the second end have a length that can absorb misalignment in a first direction between the first electrode pads and the second electrode pads and the circuit.

[0008] The second invention to achieve the above object is: a preparation step of preparing a film; an arrangement step of arranging first electrode pads and second electrode pads parallel to each other at intervals along a first direction on a peripheral edge portion of a first main surface of the film; a circuit forming process for forming a circuit having: a functional section arranged on a first main surface of the film, the functional section being made of conductive wires with insulating coating of thin metal wires and having an arbitrary pattern; a first wiring section drawn out from one of both ends of the functional section to the outside of the functional section; a second wiring section drawn out from the other of both ends of the functional section to the outside of the functional section; a first end section extending from the first wiring section in a first direction so as to overlap the first electrode pads and the second electrode pads; and a second end section extending from the second wiring section along the first end section so as to overlap the first electrode pads and the second electrode pads; and a first connecting step of removing the insulating coating of the conductive wire located on the first electrode pad and electrically connecting the exposed thin metal wire and the first electrode pad; a second connecting step of removing the insulating coating of the conductive wire located on the second electrode pad and electrically connecting the exposed thin metal wire to the second electrode pad; one end of the first end portion connected to the first wiring portion and one end of the second end portion connected to the second wiring portion are disposed at positions sandwiching the first electrode pad and the second electrode pad in a plan view; The ultrasonic welding machine has a horn that applies ultrasonic vibrations to melt the contact surface of the film with the conductive wire and embed the conductive wire in the first main surface of the film, and a conductive wire that passes through the inside of the horn and is continuously drawn out from the tip of the horn onto the first main surface of the film, In this method for manufacturing a circuit-embedded substrate, the first end and the second end have a length that can absorb misalignment in a first direction between the first electrode pads and the second electrode pads and the circuit.

[0009] According to the manufacturing methods of the first and second aspects of the present invention, even if the embedded positions of the first and second electrode pads and the first end and second end are misaligned in the first direction relative to each other, the first end and second end each have a length that absorbs the misalignment in the first direction between the two electrode pads and the circuit, so that the first end and second end each have a portion that overlaps with the two electrode pads. This improves the alignment accuracy between the circuit and the two electrode pads, thereby improving the yield rate.

[0010] The third invention to achieve the above object is: a preparation step of preparing a film; an arrangement step of arranging a first electrode pad, a second electrode pad, a third electrode pad, and a fourth electrode pad in parallel to one another at intervals along a first direction on a peripheral edge portion of a first main surface of the film; a first circuit formation step of embedding the first functional section, the first wiring section, the second wiring section, and portions of the first end and second end that do not overlap with the first electrode pads, the second electrode pads, the third electrode pads, and the fourth electrode pads into the first main surface of the film using an ultrasonic welding machine to form a first circuit having: a first functional section arranged on the first main surface of the film, the first conductive line being an insulating-coated thin metal wire and having an arbitrary pattern; a first wiring section drawn out from one of both ends of the first functional section to the outside of the first functional section; a second wiring section drawn out from the other of both ends of the first functional section to the outside of the first functional section; a first end portion extending from the first wiring section in a first direction to partially overlap with the first, second, third, and fourth electrode pads; and a second end portion extending from the second wiring section along the first end portion to partially overlap with the first, second, third, and fourth electrode pads; a second circuit forming step of embedding the second functional section, the third wiring section, the fourth wiring section, and portions of the third end and fourth end that do not overlap with the first electrode pads, the second electrode pads, the third electrode pads, and the fourth electrode pads in the first main surface of the film using an ultrasonic welding machine to form a second circuit having: a second functional section arranged on the first main surface of the film, the second functional section being made of second conductive wires with an insulating coating of thin metal wires and having an arbitrary pattern; a third wiring section drawn out from one of both ends of the second functional section to the outside of the second functional section; a fourth wiring section drawn out from the other of both ends of the second functional section to the outside of the second functional section; a third end portion extending from the third wiring section in the first direction to partially overlap with the first, second, third, and fourth electrode pads; and a fourth end portion extending from the fourth wiring section along the third end to partially overlap with the first, second, third, and fourth electrode pads; a first connecting step of removing the insulating coating of the first conductive wire located on the first electrode pad and electrically connecting the exposed thin metal wire and the first electrode pad; a second connecting step of removing the insulating coating of the first conductive wire located on the second electrode pad and electrically connecting the exposed thin metal wire to the second electrode pad; a third connecting step of removing the insulating coating of the second conductive wire located on the third electrode pad and electrically connecting the exposed thin metal wire and the third electrode pad; a fourth connecting step of removing the insulating coating of the second conductive wire located on the fourth electrode pad and electrically connecting the exposed thin metal wire and the fourth electrode pad; one end of the first end connected to the first wiring portion, one end of the second end connected to the second wiring portion, one end of the third end connected to the third wiring portion, and one end of the fourth end connected to the fourth wiring portion are arranged on the same side of the first electrode pad, the second electrode pad, the third electrode pad, and the fourth electrode pad in a plan view; In the first circuit forming step, the ultrasonic welding machine has a horn that applies ultrasonic vibrations to melt the contact surface of the film with the first conductive wire and embed the first conductive wire in the first main surface of the film, and the first conductive wire passes through the inside of the horn and is continuously drawn out from the tip of the horn onto the first main surface of the film, In the second circuit forming step, the ultrasonic welding machine has a horn that applies ultrasonic vibrations to melt the contact surface of the film with the second conductive wire and embed the second conductive wire in the first main surface of the film, and the second conductive wire passes through the inside of the horn and is continuously drawn out from the tip of the horn onto the first main surface of the film, A method for manufacturing a circuit-embedded substrate, wherein the first end, second end, third end, and fourth end have lengths that absorb misalignment in a first direction between the first electrode pad, second electrode pad, third electrode pad, and fourth electrode pad and the first circuit and second circuit.

[0011] The fourth invention to achieve the above object is: a preparation step of preparing a film; an arrangement step of arranging a first electrode pad, a second electrode pad, a third electrode pad, and a fourth electrode pad in parallel to one another at intervals along a first direction on a peripheral edge portion of a first main surface of the film; a first circuit formation step of embedding the first functional section, the first wiring section, the second wiring section, and portions of the first end and second end that do not overlap with the first electrode pads, the second electrode pads, the third electrode pads, and the fourth electrode pads into the first main surface of the film using an ultrasonic welding machine to form a first circuit having: a first functional section arranged on the first main surface of the film, the first conductive line being an insulating-coated thin metal wire and having an arbitrary pattern; a first wiring section drawn out from one of both ends of the first functional section to the outside of the first functional section; a second wiring section drawn out from the other of both ends of the first functional section to the outside of the first functional section; a first end portion extending from the first wiring section in a first direction to partially overlap with the first, second, third, and fourth electrode pads; and a second end portion extending from the second wiring section along the first end portion to partially overlap with the first, second, third, and fourth electrode pads; a second circuit forming step of embedding the second functional section, the third wiring section, the fourth wiring section, and portions of the third end and fourth end that do not overlap with the first electrode pads, the second electrode pads, the third electrode pads, and the fourth electrode pads in the first main surface of the film using an ultrasonic welding machine to form a second circuit having: a second functional section arranged on the first main surface of the film, the second functional section being made of second conductive wires with an insulating coating of thin metal wires and having an arbitrary pattern; a third wiring section drawn out from one of both ends of the second functional section to the outside of the second functional section; a fourth wiring section drawn out from the other of both ends of the second functional section to the outside of the second functional section; a third end portion extending from the third wiring section in the first direction to partially overlap with the first, second, third, and fourth electrode pads; and a fourth end portion extending from the fourth wiring section along the third end to partially overlap with the first, second, third, and fourth electrode pads; a first connecting step of removing the insulating coating of the first conductive wire located on the first electrode pad and electrically connecting the exposed thin metal wire and the first electrode pad; a second connecting step of removing the insulating coating of the first conductive wire located on the second electrode pad and electrically connecting the exposed thin metal wire to the second electrode pad; a third connecting step of removing the insulating coating of the second conductive wire located on the third electrode pad and electrically connecting the exposed thin metal wire and the third electrode pad; a fourth connecting step of removing the insulating coating of the second conductive wire located on the fourth electrode pad and electrically connecting the exposed thin metal wire and the fourth electrode pad; one end of the first end portion connected to the first wiring portion and one end of the second end portion connected to the second wiring portion are arranged on the same side with respect to the first electrode pad, the second electrode pad, the third electrode pad, and the fourth electrode pad in a plan view; one end of the third end portion connected to the third wiring portion and one end of the fourth end portion connected to the fourth wiring portion are arranged on the same side with respect to the first electrode pad, the second electrode pad, the third electrode pad, and the fourth electrode pad in a plan view; one end of each of the third end and the fourth end and one end of each of the first end and the second end are arranged at positions sandwiching the first electrode pad, the second electrode pad, the third electrode pad, and the fourth electrode pad in a plan view; In the first circuit forming step, the ultrasonic welding machine has a horn that applies ultrasonic vibrations to melt the contact surface of the film with the first conductive wire and embed the first conductive wire in the first main surface of the film, and the first conductive wire passes through the inside of the horn and is continuously drawn out from the tip of the horn onto the first main surface of the film, In the second circuit forming step, the ultrasonic welding machine has a horn that applies ultrasonic vibrations to melt the contact surface of the film with the second conductive wire and embed the second conductive wire in the first main surface of the film, and the second conductive wire passes through the inside of the horn and is continuously drawn out from the tip of the horn onto the first main surface of the film, A method for manufacturing a circuit-embedded substrate, wherein the first end, second end, third end, and fourth end have lengths that absorb misalignment in a first direction between the first electrode pad, second electrode pad, third electrode pad, and fourth electrode pad and the first circuit and second circuit.

[0012] According to the manufacturing methods of the third and fourth aspects of the present invention, even if the embedding positions of the four electrode pads and the four end portions are shifted relative to each other in the first direction, the first end portion, the second end portion, the third end portion, and the fourth end portion each have a length that absorbs the positional shift in the first direction between the first circuit and the second circuit and the four electrode pads, and therefore the four end portions each have portions that overlap with the four electrode pads. Therefore, the alignment accuracy between the first circuit and the second circuit and the four electrode pads is improved, and the yield rate can be improved. [Effects of the Invention]

[0013] According to the method for manufacturing a circuit-embedded substrate of the present invention, it is possible to improve the accuracy of alignment between the circuit and the electrode pads, thereby improving the yield rate. [Brief explanation of the drawings]

[0014] [Figure 1] 1A and 1B are schematic perspective views showing a first embodiment of a method for manufacturing a circuit-embedded substrate. [Figure 2] 1A is a partially enlarged view showing an example of a first end portion and a second end portion, and FIG. [Figure 3] FIG. 10 is an enlarged view showing a state in which the electrode pad is misaligned in the +X direction. [Figure 4] FIG. 10 is an enlarged view showing a state in which the electrode pad is misaligned in the −X direction. [Figure 5] FIG. [Figure 6] FIG. 10 is a schematic perspective view showing a second embodiment of the method for manufacturing a circuit-embedded substrate. [Figure 7] 1A is a partially enlarged view showing another example of the first end portion and the second end portion, and FIG. [Figure 8] FIG. 10 is an enlarged view showing a state in which the electrode pad is misaligned in the +X direction. [Figure 9] FIG. 10 is an enlarged view showing a state in which the electrode pad is misaligned in the −X direction. [Figure 10] FIG. 10 is a schematic perspective view showing a third embodiment of the method for manufacturing a circuit-embedded substrate. [Figure 11] FIG. 10 is a schematic perspective view showing a fourth embodiment of the method for manufacturing a circuit-embedded substrate. [Figure 12] (a) Schematic plan view showing a conventional film heater. (b) AA cross-sectional view of (a). DETAILED DESCRIPTION OF THE INVENTION

[0015] First Embodiment (Overview of embedded circuit board) Referring to FIG. 1(f), the circuit-embedded substrate 1 of the first embodiment includes a film 2, a circuit 4 consisting of conductive wires 3 arranged on a first main surface 2a of the film 2, a first electrode pad 6, and a second electrode pad 7. The circuit 4 has a functional section 45, a first wiring section 43, a second wiring section 44, a first end section 41, and a second end section 42. The functional section 45 has an arbitrary pattern. The first wiring section 43 is drawn out from one end section 45a of the functional section 45. The second wiring section 44 is drawn out from the other end section 45b of the functional section 45. The first end section 41 extends from the first wiring section 43 in the +X direction (first direction) so as to partially overlap the first electrode pad 6 and the second electrode pad 7. The second end section 42 extends from the second wiring section 44 along the first end section so as to partially overlap the first electrode pad 6 and the second electrode pad 7. 2(a), one end 41a of the first end 41 connected to the first wiring portion 43 and one end 42a of the second end 42 connected to the second wiring portion 44 are arranged on the same side of the first electrode pad 6 and the second electrode pad 7 in a plan view. In other words, the ends 41a and 42a of the first end 41 and the second end 42 are both arranged in a position in the -X direction from the two electrode pads 6 and 7 in a plan view. The boundary between the other end 45b of the functional section 45 and the second wiring section 44 does not have to be clear as in FIG. 1(f), or may be clear as in one end 45a of the functional section 45.

[0016] The functional section 45, the first wiring section 43, and the second wiring section 44 are embedded in the first main surface 2a of the film 2. Referring to FIG. 2, the portions of the first end 41 and the second end 42 that overlap the electrode pads 6, 7 are not embedded in the first main surface 2a, but the other portions are embedded. More specifically, the portions embedded in the film 2 are, for example, L as shown in FIG. 2(b). d The portions that are not embedded in the film 2 are the portions that contact the upper surfaces of the electrode pads 6 and 7, and the portions that are in contact with the upper surfaces of the electrode pads 6 and 7 and the embedded portions (L d ) is a diagonal portion between the conductive wire 3 and the electrode pads 6 and 7. The conductive wire 3 needs to straddle the two electrode pads 6 and 7, but it is difficult to embed it up to the edge of the electrode pads 6 and 7 and straddle the electrode pads 6 and 7, so a diagonal portion (a portion where the conductive wire 3 is not embedded in the film 2) as shown in Figure 2(b) is created.

[0017] In this embodiment, the functional portion 45 is a heat-generating portion, and the circuit-embedded substrate 1 is a film heater. For example, applying a positive voltage to the first electrode pad 6 and a negative voltage to the second electrode pad 7 generates a current in the circuit 4 formed by the conductive wires 3, causing the functional portion 45 to heat up. The functional portion 45 has two ends 45a, 45b connected to the first wiring portion 43 and the second wiring portion 44, respectively, and has a loop-shaped pattern. More specifically, the functional portion 45 has a pattern shape that extends from the connection portion 45a with the first wiring portion 43 in the +X direction, then extends in the +Y direction, the -X direction, and the -Y direction to reach the connection portion 45b with the second wiring portion 44. In this way, the functional portion 45 has the connection portions 45a, 45b with the first wiring portion 43 and the second wiring portion 44, and has an arbitrary pattern that extends from the connection portions 45a, 45b in the XY plane.

[0018] The film 2 can have any shape, and in this embodiment, it is rectangular. The film 2 can be transparent, opaque, or colored transparent. Examples of materials that can be used for the film 2 include thermoplastic resins such as ethylene-based resins, propylene-based resins, polyolefin-based resins, thermoplastic polyester-based resins, polyamide-based resins, polyvinyl chloride, polycarbonate, and ABS resin. The film 2 may contain two or more of these. The film 2 can be appropriately added with inorganic fine powders or organic fillers, dispersants, antioxidants, compatibilizers, UV stabilizers, antiblocking agents, antistatic agents, and the like. The thickness of the film 2 is, for example, 0.05 mm to 1 mm.

[0019] 5, the conductive wire 3 is formed by covering a thin metal wire 33 with an insulating covering layer 34. The thin metal wire 33 can be made of a conductive material such as copper, iron, gold, copper-nickel, nickel-chromium, or iron-nickel-chromium. From the viewpoints of electrical resistance, durability, and cost, it is preferable to use copper or a copper alloy made by combining copper with zinc, lead, tin, silver, aluminum, nickel, beryllium, zirconium, or a combination of two or more elements. The diameter of the thin metal wire 33 is, for example, 0.01 mm to 0.5 mm.

[0020] The insulating coating layer 34 is made of insulating resin, such as polyester, polyethylene, polyurethane, polyvinyl chloride, polyamide, polyimide, polyesterimide, polyamideimide, fluororesin, etc. The diameter of the conductive wire 3 is, for example, 0.05 mm to 0.3 mm.

[0021] The two electrode pads 6 and 7 can be made of conductive materials such as copper, phosphor bronze, brass, Corson alloy, nickel, and molybdenum. These materials may be used as the base material and plated with nickel, tin, gold, silver, copper, or the like. The electrode pads 6 and 7 each have a size of, for example, 5 mm x 10 mm and a thickness of, for example, 0.1 mm. In this embodiment, the electrode pads 6 and 7 are rectangular, but are not limited to this and may be polygonal, circular, elliptical, or L-shaped.

[0022] (Method for manufacturing circuit-embedded board) An embodiment of a method for manufacturing such a circuit-embedded substrate 1 will be described with reference to FIG. The manufacturing method of the circuit-embedded substrate 1 includes a preparation step (not shown) of preparing the film 2, an arrangement step (Fig. 1(a)) of arranging the first electrode pads 6 and the second electrode pads 7 on the peripheral portion of the first main surface 2a of the film 2, a circuit formation step (Figs. 1(b) to 1(e)) of forming the circuit 4 using an ultrasonic welder 8, and first and second connection steps (Fig. 1(f)) of electrically connecting the first end 41 and the second end 42 of the circuit 4 to the electrode pads 6 and 7, respectively.

[0023] In the preparation step, the film 2 may be fixed on a stage (not shown). A jig (not shown) may also be used to facilitate alignment of the film 2. In the placement step, the first electrode pad 6 and the second electrode pad 7 are placed on the periphery of the first main surface 2a of the film 2. In other words, they are placed side by side in the X direction (first direction) along one side of the film 2 that is parallel to the X direction. The two electrode pads 6, 7 are rectangular and are placed parallel to each other with a gap in between along the X direction. The two electrode pads 6, 7 each serve as a terminal portion of the circuit-embedded substrate 1. The two electrode pads 6, 7 can be fixed on the first main surface 2a using, for example, an adhesive or the like.

[0024] 1(b), ultrasonic welding machine 8 used in the circuit formation process includes an oscillator (not shown) that generates ultrasonic vibrations, a horn 81 that propagates the ultrasonic vibrations from the oscillator, and conductive wires 3. By applying ultrasonic vibrations, horn 81 melts the contact surface of film 2 with conductive wires 3 and can embed conductive wires 3 in first main surface 2a of film 2. Conductive wires 3 pass through the inside of horn 81 and are continuously drawn out from tip 81a of horn 81 onto first main surface 2a of film 2.

[0025] 1(b), in the circuit formation process, first, a predetermined length of conductive wire 3 is drawn out from horn 81 and embedded in first main surface 2a of film 2, and then the conductive wire 3 is extended over first electrode pad 6 and second electrode pad 7 in the −X direction (first direction), and the end of the extended portion is embedded in first main surface 2a of film 2, thereby forming first end 41. At this time, the conductive wire 3 overlapping first electrode pad 6 and second electrode pad 7 is not embedded in first main surface 2a, and comes into contact with the upper surfaces of first electrode pad 6 and second electrode pad 7. 1(c)-(d), the conductive wires 3 are extracted by a predetermined length from the buried end of the first end portion 41 in the +Y direction and embedded in the first main surface 2a to form a first wiring portion 43. Next, the conductive wires 3 are extracted by a predetermined length from the buried end 43a of the first wiring portion 43 and embedded in the first main surface 2a in an arbitrary pattern extending in the XY plane to form a functional portion 45. The buried end 43a of the first wiring portion 43 becomes the starting end of the functional portion 45. In other words, the end 43a of the first wiring portion 43 becomes one 45a of both ends of the functional portion 45 (see FIG. 1(d)). Next, as shown in FIG. 1(e), a predetermined length of the conductive wire 3 is pulled out from the horn 81 and embedded in the first principal surface 2a, extending from the terminal end 45b of the functional portion 45 in the -Y direction. This forms the second wiring portion 44. The terminal end of the functional portion 45 is the starting end of the second wiring portion 44, which becomes the other end 45b of the functional portion 45. A predetermined length of the conductive wire 3 is pulled out from the embedded terminal end 44a of the second wiring portion 44 and embedded in the first principal surface 2a along the first end 41. The embedded end of the conductive wire 3 straddles the first electrode pad 6 and the second electrode pad 7, and the end of the bridge is embedded in the first principal surface 2a of the film 2, forming the second end 42. At this time, the conductive wire 3 overlapping the first electrode pad 6 and the second electrode pad 7 is not embedded in the first principal surface 2a but contacts the upper surfaces of the first electrode pad 6 and the second electrode pad 7. After forming the second end 42, the conductive wire 3 is cut at the embedded end of the second end 42. The cutting can be performed using, for example, a cutter or nippers. Finally, in the first and second connection steps, as shown by point P in FIG. 1(f), the two electrode pads 6, 7 are electrically connected to the conductive wires 3 located above (in contact with) the two electrode pads 6, 7, respectively. For the connection, known metal joining techniques such as welding (resistance welding, ultrasonic welding, laser welding, etc.), soldering, brazing, etc. can be used. By these connection methods, the insulating coating layers 34 of the first end 41 and the second end 42 are melted by heat to expose the thin metal wires 33, and the exposed thin metal wires 33 can be electrically connected to the upper surfaces of the electrode pads 6, 7. The first and second connection steps may be performed separately, but are preferably performed simultaneously to improve production efficiency. In this manner, the circuit-embedded substrate 1 can be obtained.

[0026] Referring to FIG. 2(a), the first end 41 and the second end 42 each have a length L 41 and L 42 As shown in FIG. 2(b), the first end 41 straddles the electrode pads 6 and 7, and both ends of the first end 41 are embedded in the film 2. Since the electrode pads 6 and 7 cannot be disposed in the locations where the conductive wires 3 are to be embedded, the embedding length is set to L d Then, the allowable length of misalignment of each electrode pad 6, 7 is L 41 -2L d In other words, this length L 41 -2L d is the substantial length of the first end 41 that absorbs the positional deviation in the X direction (first direction) between the electrode pads 6, 7 and the circuit 4. 42 Regarding the second electrode pad 7, since it cannot be disposed beyond one end 41a of the first end 41 in the -X direction, the substantial allowable length of misalignment is L 41 -2L d is. 2 shows a state in which there is no misalignment between the first electrode pads 6 and the second electrode pads 7 and the first end 41 and the second end 42. As shown in FIG.

[0027] For example, the widths W6 and W7 of the electrode pads 6 and 7 are 5 mm, and the spacing S between the electrode pads 6 and 7 is P When the length L of the first end 41 is 2 mm, 41 is 22 mm, and the length L of the second end 42 42 can be 27 mm, and the distance between the conductive wires S W can be 5 mm.

[0028] As shown in FIG. 3, even when the positions of the electrode pads 6 and 7 are shifted by d in the +X direction, the first end 41 and the second end 42 each have a length L 41 ,L 42Therefore, it is possible to absorb the positional deviation of the electrode pads 6 and 7. Strictly speaking, the positional deviation of the first electrode pad 6 is calculated by subtracting the embedded length L from the d The value after subtracting (dL d ) In FIG. 3, for the sake of convenience, only the first electrode pad 6 after displacement is shown by a solid line. Furthermore, as shown in FIG. 4, even when the positions of the electrode pads 6 and 7 are shifted by d in the −X direction, the first end 41 and the second end 42 each have a length L that is greater than d. 41 ,L 42 4, it is possible to absorb the positional deviation of the electrode pads 6 and 7. For convenience, only the second electrode pad 7 after the positional deviation is shown by a solid line in FIG.

[0029] In this way, the first end 41 and the second end 42 each have a length L 41 ,L 42 By having this, even if the positions of the electrode pads 6, 7 relative to the film 2 are shifted by d in the X direction, the first end 41 and the second end 42 will overlap the electrode pads 6, 7. Therefore, the embedding positions of the first end 41 and the second end 42 do not need to take into account the positional shift of the electrode pads 6, 7. In other words, the first end 41 and the second end 42 can be embedded in the same positions every time the circuit-embedded substrate 1 is manufactured. Since it is possible to align the first end 41 and the second end 42 with the electrode pads 6, 7 without considering the positional shift of the electrode pads 6, 7, the yield rate can be improved.

[0030] Second Embodiment (Overview of embedded circuit board) Referring to FIG. 6(f), the circuit-embedded board 1 of the second embodiment includes a film 2, a circuit 4 consisting of conductive lines 3 arranged on a first main surface 2a of the film 2, a first electrode pad 6, and a second electrode pad 7. The differences from the first embodiment are the pattern shape of the functional section 45 and the positions of one end 41a of the first end 41 and one end 42a of the second end 42. The rest of the configuration is the same as that described in the first embodiment, so a description thereof will be omitted. The following description will focus on the differences from the first embodiment. In the second embodiment, the pattern shape of the functional section 45 is a meandering shape. Note that the boundary between one end 45a of the functional section 45 and the first wiring section 43 and the boundary between the other end 45b of the functional section 45 and the second wiring section 44 may not be clear as shown in Fig. 6(d) or may be clear with the ends 45a, 45b as boundaries.

[0031] (Method for manufacturing circuit-embedded board) An embodiment of a method for manufacturing such a circuit-embedded substrate 1 will be described with reference to FIG. The method for manufacturing the circuit-embedded substrate 1 includes a preparation step (not shown) of preparing the film 2, an arrangement step (FIG. 6(a)) of arranging the first electrode pads 6 and the second electrode pads 7 on the peripheral portion of the first main surface 2a of the film 2, a circuit formation step (FIGS. 6(b) to 6(e)) of forming the circuit 4 using an ultrasonic welder 8, and first and second connection steps (FIG. 6(f)) of electrically connecting the first end 41 and the second end 42 of the circuit 4 to the electrode pads 6, 7, respectively. Note that the preparation step, the arrangement step, part of the circuit formation step (FIG. 6(b)), and the first and second connection steps (FIG. 6(f)) are the same as those in the first embodiment, so their explanations will be omitted and the explanation will begin with FIG. 6(c).

[0032] As shown in FIGS. 6(c) and 6(d), the conductive wire 3 is extracted by a predetermined length from the buried termination 41a of the first end 41 in the +Y direction and embedded in the first main surface 2a to form the first wiring portion 43. Next, the conductive wire 3 is extracted by a predetermined length from the buried termination 43a of the first wiring portion 43 and embedded in the first main surface 2a in a meandering shape extending in the XY plane to form the functional portion 45. The buried termination 43a of the first wiring portion 43 becomes the starting end of the functional portion 45. In other words, the termination 43a of the first wiring portion 43 becomes one 45a of both ends of the functional portion 45 (see FIG. 6(d)). 6(d), a predetermined length of the conductive wire 3 is drawn out from the horn 81, and the conductive wire 3 extends in the -Y direction from the end 45b of the functional portion 45 and is embedded in the first main surface 2a to form the second wiring portion 44. The end of the functional portion 45 is the starting end of the second wiring portion 44, which becomes the other end 45b of the functional portion 45. 6(e), the conductive wire 3 is pulled out by a predetermined length from the buried terminal end 44a of the second wiring portion 44, and is buried in the first main surface 2a along the first end 41, spanning over the first electrode pad 6 and the second electrode pad 7, and the spanning end is buried in the first main surface 2a of the film 2, thereby forming the second end 42. At this time, the conductive wire 3 overlapping the first electrode pad 6 and the second electrode pad 7 is not buried in the first main surface 2a, but is in contact with the upper surfaces of the first electrode pad 6 and the second electrode pad 7. After the second end 42 is formed, the conductive wire 3 is cut at the buried terminal end of the second end 42.

[0033] 7(a), one end 41a of the first end 41 connected to the first wiring portion 43 and one end 42a of the second end 42 connected to the second wiring portion 44 are disposed at positions sandwiching the first electrode pad 6 and the second electrode pad 7 in a planar view. In other words, one end 41a of the first end 41 is disposed in a position in the +X direction relative to the electrode pads 6 and 7 in a planar view, and one end 42a of the second end 42 is disposed in a position in the −X direction relative to the electrode pads 6 and 7 in a planar view.

[0034] The first end 41 and the second end 42 each have a length L 41 and L 42 (L 41 <L 42 7(b), the first end 41 straddles the electrode pads 6 and 7, and both ends of the first end 41 are embedded in the film 2. Since the electrode pads 6 and 7 cannot be disposed in the locations where the conductive wires 3 are to be embedded, the embedding length is set to L d Then, the allowable length of misalignment of each electrode pad 6, 7 is L 41 -2L d In other words, this length L 41 -2L d is the substantial length of the first end 41 that absorbs the positional deviation in the X direction (first direction) between the electrode pads 6, 7 and the circuit 4. 42 Regarding the second electrode pad 7, since it cannot be disposed beyond the other end 41b of the first end 41 in the -X direction, the substantial allowable length of misalignment is L 41 -2Ld is. 7 shows a state in which there is no misalignment between the first electrode pads 6 and the second electrode pads 7 and the first end 41 and the second end 42. As shown in FIG.

[0035] For example, the widths W6 and W7 of the electrode pads 6 and 7 are 5 mm, and the spacing S between the electrode pads 6 and 7 is P When the length L of the first end 41 is 2 mm, 41 is 22 mm, and the length L of the second end 42 42 can be 27 mm, and the distance between the conductive wires S W can be 5 mm.

[0036] As shown in FIG. 8, even when the positions of the electrode pads 6 and 7 are shifted by d in the +X direction, the first end 41 and the second end 42 each have a length L 41 ,L 42 8, it is possible to absorb the positional deviation of the electrode pads 6, 7. For convenience, only the first electrode pad 6 after the positional deviation is shown by a solid line in FIG. 9, even when the positions of the electrode pads 6 and 7 are shifted by d in the −X direction, the first end 41 and the second end 42 each have a length L 41 ,L 42 , it is possible to absorb the positional deviation of the electrode pads 6 and 7. In this case, strictly speaking, the positional deviation of the second electrode pad 7 is the difference between d and the embedded length L d The value after subtracting (dL d 9, for the sake of convenience, only the second electrode pad 7 after displacement is shown by a solid line.

[0037] In this way, the first end 41 and the second end 42 each have a length L 41 ,L 42By having this, even if the positions of the electrode pads 6, 7 relative to the film 2 are shifted by d in the X direction, the first end 41 and the second end 42 will overlap the electrode pads 6, 7. Therefore, the embedding positions of the first end 41 and the second end 42 do not need to take into account the positional shift of the electrode pads 6, 7. In other words, the first end 41 and the second end 42 can be embedded in the same positions every time the circuit-embedded substrate 1 is manufactured. Since it is possible to align the first end 41 and the second end 42 with the electrode pads 6, 7 without considering the positional shift of the electrode pads 6, 7, the yield rate can be improved.

[0038] <Third embodiment> (Overview of embedded circuit board) Referring to Figure 10(f), the circuit-embedded substrate 1 of the third embodiment includes a film 2, a first circuit 4 consisting of a first conductive wire 31, a second circuit 5 consisting of a second conductive wire 32, a first electrode pad 6, a second electrode pad 7, a third electrode pad 9, and a fourth electrode pad 10, all of which are arranged on a first main surface 2a of the film 2. The first circuit 4 has a first functional portion 45, a first wiring portion 43, a second wiring portion 44, a first end portion 41, and a second end portion 42. The first functional portion 45 has an arbitrary pattern. The first wiring portion 43 is drawn out from one end 45a of the first functional portion 45. The second wiring portion 44 is drawn out from the other end 45b of the first functional portion 45. The first end portion 41 extends from the first wiring portion 43 in the +X direction (first direction) so as to partially overlap the four electrode pads 6, 7, 9, and 10. The second end portion 42 extends from the second wiring portion 44 along the first end portion 41 so as to partially overlap the four electrode pads 6, 7, 9, and 10. The second circuit 5 has a second functional portion 55, a third wiring portion 53, a fourth wiring portion 54, a third end portion 51, and a fourth end portion 52. The second functional portion 55 has an arbitrary pattern. The third wiring portion 53 is drawn out from one end 55a of the second functional portion 55. The fourth wiring portion 54 is drawn out from the other end 55b of the functional portion 55. The third end portion 51 extends from the third wiring portion 53 in the +X direction (first direction) so as to partially overlap the four electrode pads 6, 7, 9, and 10. The fourth end portion 52 extends from the fourth wiring portion 54 along the third end portion 51 so as to partially overlap the four electrode pads 6, 7, 9, and 10. One end 41a of the first end 41 connected to the first wiring portion 43, one end 42a of the second end 42 connected to the second wiring portion 44, one end 51a of the third end 51 connected to the third wiring portion 53, and one end 52a of the fourth end 52 connected to the fourth wiring portion 54 are arranged on the same side of the four electrode pads 6, 7, 9, and 10 in a planar view. In other words, the ends 41a, 42a, 51a, and 52a of the four end portions 41, 42, 51, and 52 are all arranged in the -X direction from the four electrode pads 6, 7, 9, and 10 in a planar view. The boundary between the other end 55b of the second functional section 55 and the fourth wiring section 54 does not have to be clear as in Figure 10(e), or it may be clear as in one end 55a of the second functional section 55.

[0039] (Method for manufacturing circuit-embedded board) An embodiment of a method for manufacturing such a circuit-embedded substrate 1 will be described with reference to FIG. The manufacturing method of the circuit-embedded substrate 1 includes a preparation step (not shown) of preparing the film 2, an arrangement step (FIG. 10(a)) of arranging the first electrode pad 6, the second electrode pad 7, the third electrode pad 9, and the fourth electrode pad 10 on the peripheral portion of the first main surface 2a of the film 2, a first circuit formation step (FIGS. 10(b) to 10(c)) of forming the first circuit 4 using an ultrasonic welder 8, a second circuit formation step (FIGS. 10(d) to 10(e)) of forming the second circuit 5 using the ultrasonic welder 8, and first to fourth connection steps (FIG. 10(f)) of electrically connecting the first end 41, the second end 42, the third end 51, and the fourth end 52 to the four electrode pads 6, 7, 9, and 10, respectively. The preparation process, arrangement process, first circuit formation process (FIGS. 10(b) to 10(c)), and first to fourth connection processes (FIG. 10(f)) are the same as those in the first embodiment, so their explanations will be omitted and only the second circuit formation process (FIGS. 10(d) to 10(e)) will be explained.

[0040] First, the second conductive wire 32 is drawn out from the horn 81 by a predetermined length and embedded in the first main surface 2a of the film 2, and then straddles over the four electrode pads 6, 7, 9, and 10 in the −X direction (first direction). The straddled end is then embedded in the first main surface 2a of the film 2, thereby forming the third end 51. The third end 51 is formed parallel to the first end 41 and the second end 42. Next, the second conductive wires 32 are pulled out a predetermined length from the buried end of the third end 51 in the +Y direction and embedded in the first main surface 2a to form a third wiring portion 53. Next, the second conductive wires 32 are pulled out a predetermined length from the buried end 53a of the third wiring portion 53 and embedded in the first main surface 2a in an arbitrary pattern extending in the XY plane to form a second functional portion 55. The buried end 53a of the third wiring portion 53 becomes the starting end of the second functional portion 55. In other words, the end 53a of the third wiring portion 53 becomes one of both ends 55a of the second functional portion 55 (see FIG. 10(e)). 10(e), the second conductive wire 32 is pulled out a predetermined length from the horn 81, and extends from the end 55b of the second functional portion 55 in the -Y direction and embedded in the first main surface 2a to form the fourth wiring portion 54. The end of the second functional portion 55 is the starting end of the fourth wiring portion 54, and becomes the other end 55b of the second functional portion 55. The second conductive wire 32 is pulled out a predetermined length from the embedded end 54a of the fourth wiring portion 54, and embedded in the first main surface 2a along the third end 51, and extends over the four electrode pads 6, 7, 9, and 10 in the +X direction. The end of the spanning portion is embedded in the first main surface 2a of the film 2 to form the fourth end 52.

[0041] In the third embodiment, as in the first embodiment, one ends 41a, 42a, 51a, 52a of the four end portions 41, 42, 51, 52 are arranged on the same side of the four electrode pads 6, 7, 9, 10 in a plan view. Therefore, the same effects as in the first embodiment are achieved. That is, the four end portions 41, 42, 51, 52 can be embedded in the same positions every time a circuit-embedded substrate 1 is manufactured. Since it is possible to align the four end portions 41, 42, 51, 52 with the four electrode pads 6, 7, 9, 10 without considering misalignment of the four electrode pads 6, 7, 9, 10, the yield rate can be improved.

[0042] <Fourth embodiment> (Overview of embedded circuit board) 11(f), the circuit-embedded substrate 1 of the fourth embodiment includes a film 2, a first circuit 4 consisting of a first conductive wire 31, a second circuit 5 consisting of a second conductive wire 32, a first electrode pad 6, a second electrode pad 7, a third electrode pad 9, and a fourth electrode pad 10, all of which are arranged on a first main surface 2a of the film 2. The fourth embodiment differs from the third embodiment in the positions of ends 41a and 42a of the two end portions 41 and 42, respectively, and ends 51a and 52a of the two end portions 51 and 52, respectively. The remaining configuration is the same as that described in the third embodiment, and therefore a description thereof will be omitted. The following description will focus on the differences from the third embodiment.

[0043] 11(c), one end 41a of the first end 41 connected to the first wiring portion 43 and one end 42a of the second end 42 connected to the second wiring portion 44 are located in the +X direction from the four electrode pads 6, 7, 9, and 10 in a plan view. Referring to FIG. 11(f), one end 51a of the third end 51 connected to the third wiring portion 53 and one end 52a of the fourth end 52 connected to the fourth wiring portion 54 are located in the −X direction from the four electrode pads 6, 7, 9, and 10 in a plan view. In other words, the one ends 41a and 42a of the first end 41 and the second end 42 and the one ends 51a and 52a of the third end 51 and the fourth end 52 are located at positions sandwiching the four electrode pads 6, 7, 9, and 10.

[0044] (Method for manufacturing circuit-embedded board) An embodiment of a method for manufacturing such a circuit-embedded substrate 1 will be described with reference to FIG. The manufacturing method of the circuit-embedded substrate 1 includes an arrangement step (FIG. 11(a)) of arranging the first electrode pad 6, the second electrode pad 7, the third electrode pad 9, and the fourth electrode pad 10 on the peripheral portion of the first main surface 2a of the film 2, a first circuit formation step (FIGS. 11(b) to 11(c)) of forming the first circuit 4 using an ultrasonic welder 8, a second circuit formation step (FIGS. 11(d) to 11(e)) of forming the second circuit 5 using the ultrasonic welder 8, and first to fourth connection steps (FIG. 11(f)) of electrically connecting the first end 41, the second end 42, the third end 51, and the fourth end 52 to the four electrode pads 6, 7, 9, and 10, respectively. The preparation process, arrangement process, second circuit formation process (FIGS. 11(d) to 11(e)), and first to fourth connection processes (FIG. 11(f)) are the same as those in the third embodiment, so their explanations will be omitted and only the first circuit formation process (FIGS. 11(b) to 11(c)) will be explained.

[0045] First, the first conductive wire 31 is pulled out from the horn 81 by a predetermined length and embedded in the first main surface 2a of the film 2, and then straddles the four electrode pads 6, 7, 9, and 10 in the +X direction (first direction), and the end of the straddle is embedded in the first main surface 2a of the film 2 to form the first end portion 41. Next, the first conductive wire 31 is pulled out a predetermined length from the buried terminal end 43a of the first end portion 41 in the +Y direction and embedded in the first main surface 2a to form the first wiring portion 43. Next, the first conductive wire 31 is pulled out a predetermined length from the buried terminal end 43a of the first wiring portion 43 and embedded in the first main surface 2a in an arbitrary pattern extending in the XY plane to form the first functional portion 45. The buried terminal end 43a of the first wiring portion 43 becomes the starting end of the first functional portion 45. In other words, the terminal end 43a of the first wiring portion 43 becomes one end 45a of the first functional portion 45 (see FIG. 11(b)). Next, as shown in FIG. 11(c), a predetermined length of the first conductive wire 31 is pulled out from the horn 81, and the first conductive wire 31 extends from the terminal end 45b of the first functional portion 45 in the -Y direction and is embedded in the first main surface 2a to form the second wiring portion 44. The terminal end of the first functional portion 45 is the starting end of the second wiring portion 44, which becomes the other end 45b of the first functional portion 45. The first conductive wire 31 is pulled out a predetermined length from the embedded terminal end 44a of the second wiring portion 44, and is embedded in the first main surface 2a along the first end 41, spanning over the four electrode pads 6, 7, 9, and 10 in the -X direction. The end of the spanning portion is embedded in the first main surface 2a of the film 2 to form the second end 42. The second end 42 is formed parallel to the first end 41.

[0046] In the fourth embodiment, similarly to the second embodiment, one ends 41a, 42a of the two end portions 41, 42 are disposed on the same side (+X) of the four electrode pads 6, 7, 9, 10 in a plan view. Furthermore, one ends 51a, 52a of the two end portions 51, 52 are disposed on the same side (-X) of the four electrode pads 6, 7, 9, 10 in a plan view. In other words, the two sets of one ends (41a, 42a and 51a, 52a) are disposed at positions sandwiching the four electrode pads 6, 7, 9, 10 in a plan view. Therefore, the same effects as the second embodiment can be achieved. That is, the four end portions 41, 42, 51, 52 can be embedded in the same positions every time the circuit-embedded substrate 1 is manufactured. Since it is possible to align the four end portions 41, 42, 51, 52 with the four electrode pads 6, 7, 9, 10 without taking into consideration misalignment of the four electrode pads 6, 7, 9, 10, it is possible to improve the yield rate. [Explanation of symbols]

[0047] 1: Circuit embedded board 2: Film 2a: 1st principal surface 3: Conductive wire 31: First conductive wire 32: Second conductive wire 33: Fine metal wire 34: Insulating coating layer 4:(1st) circuit 41:First end 42:Second end 43: 1st wiring section 44: 2nd wiring section 45: (1st) Functional section 5: 2nd circuit 51:Third end 52: 4th end 53: 3rd wiring section 54: 4th wiring section 55: Second functional section 6: First electrode pad 7: Second electrode pad 8: Ultrasonic welding machine 81: Horn 9: Third electrode pad 10: 4th electrode pad 100: Film heater 200:Film 300: Fine metal wire 400: Circuit 410: First end 420:Second end 430: 1st wiring section 440: 2nd wiring section 450: Heater section 500: First electrode pad 600: Second electrode pad 700: Adhesive layer

Claims

1. a preparation step of preparing a film; an arrangement step of arranging first electrode pads and second electrode pads parallel to each other at intervals along a first direction on a peripheral edge portion of the first main surface of the film; a circuit forming process for forming a circuit including: a functional section disposed on the first main surface of the film, the functional section being made of conductive wires with an insulation coating of thin metal wires and having an arbitrary pattern; a first wiring section drawn out from one of both ends of the functional section to the outside of the functional section; a second wiring section drawn out from the other of both ends of the functional section to the outside of the functional section; a first end section extending from the first wiring section in the first direction to partially overlap the first electrode pads and the second electrode pads; and a second end section extending from the second wiring section along the first end section to partially overlap the first electrode pads and the second electrode pads; and a first connecting step of removing the insulating coating of the conductive wire located on the first electrode pad and electrically connecting the exposed thin metal wire and the first electrode pad; a second connecting step of removing the insulating coating of the conductive wire located on the second electrode pad and electrically connecting the exposed thin metal wire and the second electrode pad, one end of the first end portion connected to the first wiring portion and one end of the second end portion connected to the second wiring portion are disposed on the same side with respect to the first electrode pad and the second electrode pad in a plan view, the ultrasonic welding machine includes a horn that applies ultrasonic vibrations to melt a contact surface of the film with the conductive wire and embed the conductive wire in the first main surface of the film, and the conductive wire passes through the inside of the horn and is continuously drawn out from a tip of the horn onto the first main surface of the film, The first end and the second end have a length that absorbs misalignment in the first direction between the first electrode pad and the second electrode pad and the circuit.

2. a preparation step of preparing a film; an arrangement step of arranging first electrode pads and second electrode pads parallel to each other at intervals along a first direction on a peripheral edge portion of the first main surface of the film; a circuit forming process for forming a circuit including: a functional section disposed on the first main surface of the film, the functional section being made of conductive wires with an insulation coating of thin metal wires and having an arbitrary pattern; a first wiring section drawn out from one of both ends of the functional section to the outside of the functional section; a second wiring section drawn out from the other of both ends of the functional section to the outside of the functional section; a first end section extending from the first wiring section in the first direction to partially overlap the first electrode pads and the second electrode pads; and a second end section extending from the second wiring section along the first end section to partially overlap the first electrode pads and the second electrode pads; and a first connecting step of removing the insulating coating of the conductive wire located on the first electrode pad and electrically connecting the exposed thin metal wire and the first electrode pad; a second connecting step of removing the insulating coating of the conductive wire located on the second electrode pad and electrically connecting the exposed thin metal wire and the second electrode pad, one end of the first end portion connected to the first wiring portion and one end of the second end portion connected to the second wiring portion are disposed at positions sandwiching the first electrode pad and the second electrode pad in a plan view, the ultrasonic welding machine includes a horn that applies ultrasonic vibrations to melt a contact surface of the film with the conductive wire and embed the conductive wire in the first main surface of the film, and the conductive wire passes through the inside of the horn and is continuously drawn out from a tip of the horn onto the first main surface of the film, The first end and the second end have a length that absorbs misalignment in the first direction between the first electrode pad and the second electrode pad and the circuit.

3. a preparation step of preparing a film; an arrangement step of arranging a first electrode pad, a second electrode pad, a third electrode pad, and a fourth electrode pad in parallel to one another at intervals along a first direction on a peripheral edge portion of the first main surface of the film; a first circuit forming step of embedding, in the first main surface of the film using an ultrasonic welding machine, the first circuit including: a first functional unit arranged on the first main surface of the film, the first conductive line being made of an insulatingly coated thin metal wire and having an arbitrary pattern; a first wiring unit drawn from one of both ends of the first functional unit to the outside of the first functional unit; a second wiring unit drawn from the other of both ends of the first functional unit to the outside of the first functional unit; a first end portion extending from the first wiring unit in the first direction to partially overlap with the first electrode pad, the second electrode pad, the third electrode pad, and the fourth electrode pad; and a second end portion extending from the second wiring unit along the first end portion to partially overlap with the first electrode pad, the second electrode pad, the third electrode pad, and the fourth electrode pad; a second circuit forming step of embedding, in the first main surface of the film, the second functional unit, the third wiring unit, the fourth wiring unit, and portions of the third end and fourth end that do not overlap with the first electrode pads, the second electrode pads, the third electrode pads, and the fourth electrode pads, in the first main surface of the film using the ultrasonic welding machine to form a second circuit having a second functional unit arranged on the first main surface of the film, the second functional unit being made of a second conductive wire having an arbitrary pattern and made of an insulating-coated thin metal wire; a third wiring unit drawn from one of both ends of the second functional unit to the outside of the second functional unit; a fourth wiring unit drawn from the other of both ends of the second functional unit to the outside of the second functional unit; a third end portion extending from the third wiring unit in the first direction to partially overlap with the first electrode pads, the second electrode pads, the third electrode pads, and the fourth electrode pads; a first connecting step of removing the insulating coating of the first conductive wire located on the first electrode pad and electrically connecting the exposed thin metal wire and the first electrode pad; a second connecting step of removing the insulating coating of the first conductive wire located on the second electrode pad and electrically connecting the exposed thin metal wire and the second electrode pad; a third connection step of removing the insulating coating of the second conductive wire located on the third electrode pad and electrically connecting the exposed thin metal wire and the third electrode pad; a fourth connecting step of removing the insulating coating of the second conductive wire located on the fourth electrode pad and electrically connecting the exposed thin metal wire and the fourth electrode pad; one end of the first end portion connected to the first wiring portion, one end of the second end portion connected to the second wiring portion, one end of the third end portion connected to the third wiring portion, and one end of the fourth end portion connected to the fourth wiring portion are arranged on the same side with respect to the first electrode pad, the second electrode pad, the third electrode pad, and the fourth electrode pad in a plan view; In the first circuit forming step, the ultrasonic welding machine has a horn that applies ultrasonic vibrations to melt a contact surface of the film with the first conductive wire and embed the first conductive wire in the first main surface of the film, and the first conductive wire passes through the inside of the horn and is continuously drawn out from a tip of the horn onto the first main surface of the film, In the second circuit forming step, the ultrasonic welding machine has the horn that applies ultrasonic vibrations to melt a contact surface of the film with the second conductive wire and embed the second conductive wire in the first main surface of the film, and the second conductive wire passes through the inside of the horn and is continuously drawn out from a tip of the horn onto the first main surface of the film, a first end portion, a second end portion, a third end portion, and a fourth end portion each having a length that absorbs misalignment in the first direction between the first electrode pad, the second electrode pad, the third electrode pad, and the fourth electrode pad and the first circuit and the second circuit;

4. a preparation step of preparing a film; an arrangement step of arranging a first electrode pad, a second electrode pad, a third electrode pad, and a fourth electrode pad in parallel to one another at intervals along a first direction on a peripheral edge portion of the first main surface of the film; a first circuit forming step of embedding, in the first main surface of the film using an ultrasonic welding machine, the first circuit including: a first functional unit arranged on the first main surface of the film, the first conductive line being made of an insulatingly coated thin metal wire and having an arbitrary pattern; a first wiring unit drawn from one of both ends of the first functional unit to the outside of the first functional unit; a second wiring unit drawn from the other of both ends of the first functional unit to the outside of the first functional unit; a first end portion extending from the first wiring unit in the first direction to partially overlap with the first electrode pad, the second electrode pad, the third electrode pad, and the fourth electrode pad; and a second end portion extending from the second wiring unit along the first end portion to partially overlap with the first electrode pad, the second electrode pad, the third electrode pad, and the fourth electrode pad; a second circuit forming step of embedding, in the first main surface of the film, the second functional unit, the third wiring unit, the fourth wiring unit, and portions of the third end and fourth end that do not overlap with the first electrode pads, the second electrode pads, the third electrode pads, and the fourth electrode pads, in the first main surface of the film using the ultrasonic welding machine to form a second circuit having a second functional unit arranged on the first main surface of the film, the second functional unit being made of a second conductive wire having an arbitrary pattern and made of an insulating-coated thin metal wire; a third wiring unit drawn from one of both ends of the second functional unit to the outside of the second functional unit; a fourth wiring unit drawn from the other of both ends of the second functional unit to the outside of the second functional unit; a third end portion extending from the third wiring unit in the first direction to partially overlap with the first electrode pads, the second electrode pads, the third electrode pads, and the fourth electrode pads; a first connecting step of removing the insulating coating of the first conductive wire located on the first electrode pad and electrically connecting the exposed thin metal wire and the first electrode pad; a second connecting step of removing the insulating coating of the first conductive wire located on the second electrode pad and electrically connecting the exposed thin metal wire and the second electrode pad; a third connection step of removing the insulating coating of the second conductive wire located on the third electrode pad and electrically connecting the exposed thin metal wire and the third electrode pad; a fourth connecting step of removing the insulating coating of the second conductive wire located on the fourth electrode pad and electrically connecting the exposed thin metal wire and the fourth electrode pad; one end of the first end portion connected to the first wiring portion and one end of the second end portion connected to the second wiring portion are arranged on the same side with respect to the first electrode pad, the second electrode pad, the third electrode pad, and the fourth electrode pad in a plan view; one end of the third end portion connected to the third wiring portion and one end of the fourth end portion connected to the fourth wiring portion are arranged on the same side with respect to the first electrode pad, the second electrode pad, the third electrode pad, and the fourth electrode pad in a plan view; the one end of each of the third end portion and the fourth end portion and the one end of each of the first end portion and the second end portion are disposed at positions sandwiching the first electrode pad, the second electrode pad, the third electrode pad, and the fourth electrode pad in a plan view, In the first circuit forming step, the ultrasonic welding machine has a horn that applies ultrasonic vibrations to melt a contact surface of the film with the first conductive wire and embed the first conductive wire in the first main surface of the film, and the first conductive wire passes through the inside of the horn and is continuously drawn out from a tip of the horn onto the first main surface of the film, In the second circuit forming step, the ultrasonic welding machine has the horn that applies ultrasonic vibrations to melt a contact surface of the film with the second conductive wire and embed the second conductive wire in the first main surface of the film, and the second conductive wire passes through the inside of the horn and is continuously drawn out from a tip of the horn onto the first main surface of the film, a first end portion, a second end portion, a third end portion, and a fourth end portion each having a length that absorbs misalignment in the first direction between the first electrode pad, the second electrode pad, the third electrode pad, and the fourth electrode pad and the first circuit and the second circuit;

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