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 one thin metal wire and having a function part in an arbitrary pattern, two wiring parts drawn out from both ends thereof, and two end parts extending opposite to the function part from the wiring parts, partially overlapping with the electrode pads, and forming two displacement absorption regions, using an ultrasonic welder; and connecting the electrode pads and the thin metal wire thereon. The ultrasonic welder includes a horn that embeds the thin metal wire in the film by melting a contact surface of the film with the thin metal wire with ultrasonic vibration, and the thin metal wire drawn out through the inside. The two displacement absorption regions include an end part with a curved shape and have the width that absorbs the 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 in which a single thin metal wire is embedded in a film in an arbitrary pattern is known (see, for example, Patent Document 1). Referring to Fig. 10, 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 in the film 200 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. 10(a), for example, the embedded position of the thin metal wires 300 will be relatively misaligned in the -Y direction in FIG. 10(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 including a functional section having an arbitrary pattern and made of one thin metal wire arranged on the first main surface, a first wiring section drawn out from one of both ends of the functional section, a second wiring section drawn out from the other of both ends of the functional section, and first and second wiring sections extending from the first and second wiring sections to opposite sides of the functional section, respectively, and partially overlapping the first and second electrode pads, respectively, to form a first end portion constituting a first misalignment absorption region and a second end portion constituting a second misalignment absorption region, by embedding the functional section, the first wiring section, the second wiring section, and portions of the first end portion and the second end portion that do not overlap the first and second electrode pads in the first main surface of the film using an ultrasonic welding machine; a connecting step of electrically connecting the first electrode pads and the second electrode pads to the thin metal wires located on the first electrode pads and the second electrode pads, respectively; The ultrasonic welding machine has a horn that applies ultrasonic vibrations to melt the contact surface of the film with the thin metal wire and embed the thin metal wire in the first main surface of the film, and the thin metal 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 misalignment absorption region and the second misalignment absorption region are composed of first and second curved end portions, and each have a width that absorbs misalignment in a first direction between the first electrode pad and the second electrode pad and the circuit.

[0008] According to this manufacturing method, even if the embedded positions of the first and second electrode pads and the first and second ends are misaligned in the first direction relative to each other, the first and second ends have portions that overlap with the first and second electrode pads, respectively, because the first and second ends are curved and have widths that absorb the misalignment in the first direction between the first and second electrode pads and the circuit. This improves the alignment accuracy between the electrode pads and the circuit, thereby improving the yield rate.

[0009] A second invention is a method for manufacturing a circuit-embedded substrate according to the first invention, wherein the bent shape is a zigzag shape or a U-shape in plan view. [Effects of the Invention]

[0010] 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]

[0011] [Figure 1] 1A and 1B are schematic perspective views showing an embodiment of a method for manufacturing a circuit-embedded substrate. [Figure 2] FIG. 4 is a partially enlarged view showing an example of a first end portion and a second end portion. [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 a partially enlarged view showing another example of the first end portion and the second end portion. [Figure 5] FIG. 10 is an enlarged view showing a state in which the electrode pad is misaligned in the +X direction. [Figure 6] FIG. 6 is an enlarged view showing a state in which the electrode pad is further displaced in the +X direction from FIG. 5; [Figure 7] FIG. 10 is an enlarged view showing a state in which the electrode pad is misaligned in the −X direction. [Figure 8] FIG. 10 is an enlarged view showing a state in which an electrode pad is misaligned in the +X direction in a conventional film heater. [Figure 9] FIG. 10 is an enlarged view showing a state in which an electrode pad is misaligned in the −X direction in a conventional film heater. [Figure 10] (a) Schematic plan view showing a conventional film heater. (b) AA cross-sectional view of (a). DETAILED DESCRIPTION OF THE INVENTION

[0012] (Overview of embedded circuit board) 1(f), the circuit-embedded substrate 1 includes a film 2, a circuit 4 formed of a single thin metal wire 3 disposed on a first main surface 2a of the film 2, a first electrode pad 5, and a second electrode pad 6. The circuit 4 includes a 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 functional portion 45 has an arbitrary pattern. The first wiring portion 43 is drawn out from one end 45a of the functional portion 45. The second wiring portion 44 is drawn out from the other end 45b of the functional portion 45. The first end portion 41 extends from the first wiring portion 43 toward the opposite side of the functional portion 45 (in the -Y direction) and overlaps the first electrode pad 5. The second end portion 42 extends from the second wiring portion 44 toward the opposite side of the functional portion 45 (in the -Y direction) and overlaps the second electrode pad 6. In this embodiment, the first end portion 41 and the second end portion 42 have a zigzag shape (an example of a bent shape) in a plan view.

[0013] The functional portion 45, the first wiring portion 43, and the second wiring portion 44 are embedded in the first main surface 2a of the film 2. The portions of the first end portion 41 and the second end portion 42 that overlap the electrode pads 5, 6 are not embedded in the first main surface 2a, but the other portions are embedded. In other words, the thin metal wires 3 located above the electrode pads 5, 6 are not embedded in the first main surface 2a, but the thin metal wires 3 that are not located above the electrode pads 5, 6 are embedded.

[0014] 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 5 and a negative voltage to the second electrode pad 6 generates a current in the circuit 4 made of the thin metal 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, the -Y direction, and the +X 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.

[0015] 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.

[0016] The thin metal wires 3 can be made of conductive materials such as copper, iron, gold, copper-nickel, nickel-chromium, and 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 thereof. The diameter of the thin metal wires 3 is, for example, 0.01 mm to 0.5 mm. By making the diameter as small as possible, for example, 0.01 mm to 0.2 mm, the thin metal wires 3 can be made less noticeable.

[0017] The circuit 4 may be formed of a conductive wire consisting of thin metal wires 3 and an insulating coating layer covering the wires. The insulating coating layer is made of an insulating resin, such as polyester, polyethylene, polyurethane, polyvinyl chloride, polyamide, polyimide, polyesterimide, polyamideimide, or fluororesin. The diameter of the conductive wire is, for example, 0.05 mm to 0.3 mm.

[0018] The two electrode pads 5 and 6 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 5 and 6 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 5 and 6 are rectangular, but are not limited to this and may be polygonal, circular, elliptical, or L-shaped.

[0019] (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 5 and the second electrode pads 6 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 7, and a connection step (FIG. 1(f)) of electrically connecting the first end 41 and the second end 42 of the circuit 4 to the electrode pads 5, 6.

[0020] 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 5 and the second electrode pad 6 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 5 and 6 are rectangular and are placed parallel to each other with a gap in between along the X direction. The two electrode pads 5 and 6 each serve as a terminal portion of the circuit-embedded substrate 1. The two electrode pads 5 and 6 can be fixed on the first main surface 2a using, for example, an adhesive or the like.

[0021] 1(b), ultrasonic welding machine 7 used in the circuit formation process includes an oscillator (not shown) that generates ultrasonic vibrations, a horn 71 that propagates the ultrasonic vibrations from the oscillator, and thin metal wires 3. By applying ultrasonic vibrations, horn 71 melts the contact surface of film 2 with thin metal wires 3 and can embed thin metal wires 3 into first main surface 2a of film 2. Thin metal wires 3 pass through the inside of horn 71 and are continuously drawn out from tip 71a of horn 71 onto first main surface 2a of film 2.

[0022] 1(b), in the circuit formation process, first, a predetermined length of thin metal wire 3 is pulled out from horn 71 and embedded in first main surface 2a of film 2, and the thin metal wire 3 straddles first electrode pad 5 in a zigzag pattern to form first end 41. At this time, the bent portion of the zigzag pattern is embedded in first main surface 2a, and the thin metal wire 3 overlapping first electrode pad 5 is not embedded in first main surface 2a but comes into contact with the upper surface of first electrode pad 5. Next, as shown in FIG. 1(c), the fine metal wires 3 are pulled out a predetermined length from the buried end of the first end portion 41 toward the +Y direction and embedded in the first main surface 2a to form a first wiring portion 43. Next, the fine metal wires 3 are pulled out 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)). 1(d), a predetermined length of the thin metal wire 3 is drawn out from the horn 71, and the thin metal wire 3 is extended in the -Y direction from the end 45b of the functional portion 45 and embedded in the first main surface 2a to form the second wiring portion 44. The end 45b of the functional portion 45 is the starting end of the second wiring portion 44 and is the other of the two ends of the functional portion 45. 1(e), the thin metal wire 3 is pulled out by a predetermined length from the buried end 44a of the second wiring portion 44 and buried in the first main surface 2a, and the second end 42 is formed by spanning the second electrode pad 6 in a zigzag pattern. At this time, the bent portion of the zigzag pattern is buried in the first main surface 2a, and the thin metal wire 3 overlapping the second electrode pad 6 is not buried in the first main surface 2a but is in contact with the upper surface of the second electrode pad 6. After the second end 42 is formed, the thin metal wire 3 is cut at the buried end of the second end 42. For example, a cutter or nippers can be used as the cutting method. Finally, in the connection step, as shown by point P in FIG. 1(f), the two electrode pads 5, 6 are electrically connected to the thin metal wires 3 located on (in contact with) the two electrode pads 5, 6. For the connection, known metal joining techniques such as welding (resistance welding, ultrasonic welding, laser welding, etc.), soldering, brazing, etc. may be used. Note that the electrode pads 5, 6 and the thin metal wires 3 may be electrically connected at multiple points. In this manner, the circuit-embedded substrate 1 can be obtained.

[0023] (First embodiment of misalignment absorbing region) 2, the first end 41 and the second end 42 respectively constitute a first misalignment absorbing region 41a and a second misalignment absorbing region 42a. The first misalignment absorbing region 41a and the second misalignment absorbing region 42a are indicated by dashed lines in the figure. FIG. 2 shows a state in which there is no misalignment between the first electrode pad 5 and the second electrode pad 6 and the first end 41 and the second end 42. The first positional deviation absorbing region 41a has a width W 41 The second misalignment absorbing region 42a has a width W 42 These widths W 41 ,W 42 is set equal to the width of the zigzag shape of the end portions 41 and 42 and larger than the widths W5 and W6 of the two electrode pads 5 and 6. Naturally, the width W 41 ,W 42 If the value is increased, the allowable positional deviation of the electrode pads 5 and 6 in the X direction also increases. For example, when the widths W5 and W6 of the electrode pads 5 and 6 are 5 mm and the spacing S between the electrode pads 5 and 6 is 10 mm, the width W 41 ,W 42 may be 15 mm each.

[0024] As shown in FIG. 3, even if the positions of the electrode pads 5 and 6 are shifted by d in the +X direction, the positional deviation absorbing regions 41a and 42a each have a width W 41 ,W 42 Since the misalignment absorbing regions 41a and 42a have a width W 41 ,W 42 By virtue of this, even if the positions of the electrode pads 5, 6 relative to the film 2 are shifted by d in the X direction, the ends 41, 42 will overlap the electrode pads 5, 6. Therefore, the embedding positions of the ends 41, 42 do not need to take into account the positional shift of the electrode pads 5, 6. In other words, the ends 41, 42 can be embedded in the same positions every time the circuit-embedded substrate 1 is manufactured. In this way, it is possible to align the ends 41 and 42 with the electrode pads 5 and 6 without taking into consideration misalignment of the electrode pads 5 and 6, thereby improving the yield rate.

[0025] (Second embodiment of misalignment absorbing region) 4, the bent shapes of the first end 41 and the second end 42 may be U-shaped in a plan view. The first end 41 and the second end 42 constitute a first positional deviation absorbing region 41a and a second positional deviation absorbing region 42a, respectively. FIG. 4 shows a state in which there is no positional deviation between the first end 41 and the second end 42 and the first electrode pad 5 and the second electrode pad 6.

[0026] The first positional deviation absorbing region 41a has a width W 41 The second misalignment absorbing region 42a has a width W 42 These widths W 41 ,W 42 is equal to the width of the U-shape of the end portions 41 and 42, and satisfies the following formulas (1) and (2), respectively: where S5 and S6 are the distances between the two thin metal wires 3 that straddle each electrode pad 5 and 6 in the Y direction. W 41 =(2×W3)+S5 (1) W 42 =(2×W3)+S6 (2) When the thin metal wire 3 and the electrode pads 5 and 6 are ultrasonically welded together, the widths W of the first positional deviation absorbing region 41a and the second positional deviation absorbing region 42a are set to be equal to or smaller than the widths W of the first positional deviation absorbing region 41a and the second positional deviation absorbing region 42a. 41 ,W 42 The widths W5 and W6 of the two electrode pads 5 and 6 can be set equal to each other. When soldering the thin metal wire 3 to the electrode pads 5 and 6, the thin metal wire 3 needs to be fixed by arranging solder on both sides of the thin metal wire 3 (in other words, arranging solder at positions that sandwich the thin metal wire 3). Therefore, W5 (W6) > W 41 (W 42 ) With respect to the widths W5 and W6 of the electrode pads 5 and 6, the width (diameter) W3 of the thin metal wire 3 and the intervals S5 and S6 are set to values ​​that satisfy the following formulas (3) and (4), respectively. W5=2W3+S5 (3) W6=2W3+S6 (4) That is, once the widths W5 and W6 of the electrode pads 5 and 6 and the width (diameter) W3 of the thin metal wire 3 are determined, the intervals S5 and S6 can be calculated from the above formulas (3) and (4). For example, when the electrode pads 5 and 6 have a width W5 (= width W6) of 5 mm and the thin metal wire 3 has a width (diameter) W3 of 0.5 mm, the interval S5 (= S6) is 5 - 1 = 4 mm.

[0027] In this way, by forming the first misalignment absorption region 41a and the second misalignment absorption region 42a in a U-shape with intervals S5 and S6 therebetween, even if the electrode pads 5 and 6 are each misaligned by d (=W5 / 2=W6 / 2) in the +X direction, as shown in Fig. 5, for example, there will be a portion where the thin metal wire 3 overlaps the electrode pads 5 and 6 (a portion where the thin metal wire 3 straddles the electrode pads 5 and 6). In other words, the accuracy of aligning the electrode pads 5 and 6 with the ends 41 and 42 improves, thereby improving the yield rate.

[0028] 6 and 7, even if the electrode pads 5 and 6 are misaligned by d+d / 2 in each of the ±X directions, there will be overlapping portions between the thin metal wire 3 and the electrode pads 5 and 6 as long as the shapes of the first end 41 and the second end 42 satisfy the above formulas (3) and (4). In FIGS. 6 and 7, one thin metal wire 3 overlaps the edge of each of the electrode pads 5 and 6. As can be seen from FIGS. 6 and 7, the allowable range of misalignment of the electrode pads 5 and 6 in the X direction is d+d / 2. Here, d=W5 / 2 (=W6 / 2), so W5 / 2+W5 / 4=3W5 / 4 (=3W6 / 4).

[0029] 8 and 9, the first end 410 and the second end 420 of the conventional film heater 100 are straight. In FIGS. 8 and 9, the electrode pads 500 and 600 are misaligned in the X direction, but there are portions where the thin metal wire 300 and the electrode pads 500 and 600 overlap. The amount of misalignment of the electrode pads 500 and 600 in FIGS. 8 and 9 is half the width (W 500 / 2,W 600That is, the allowable range of positional deviation of the electrode pads 500 and 600 in the X direction is half the width of the electrode pads 500 and 600 (W 500 / 2,W 600 / 2).

[0030] In this way, by changing the shape of the first end 41 and the second end 42 from the conventional straight line to a U-shape that satisfies the above formulas (3) and (4), the tolerance for positional deviation in the X direction of the electrode pads 5, 6 increases by 1.5 times. In other words, it becomes easier to align the first end 41 and the second end 42 with the electrode pads 5, 6, thereby improving the yield rate.

[0031] In the above two embodiments, the embedded position of the thin metal wire 3 is not shifted, and the electrode pads 5, 6 are shifted, but the manufacturing method of the present invention can achieve the same effects as the above embodiments even in a configuration where the electrode pads 5, 6 are not shifted, and the embedded position of the thin metal wire 3 is shifted. Also, in a configuration where both the positions of the electrode pads 5, 6 and the embedded position of the thin metal wire 3 are shifted, the manufacturing method of the present invention can achieve the same effects as the above embodiments. [Explanation of symbols]

[0032] 1: Circuit embedded board 2: Film 2a: 1st principal surface 3: Fine metal wire 4: Circuit 41:First end 41a: First position deviation absorbing region 42:Second end 42a: Second position deviation absorbing region 43: 1st wiring section 44: 2nd wiring section 45: Functional section 5: First electrode pad 6: Second electrode pad 7: Ultrasonic welding machine 71: Horn 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 thin metal wire disposed on the first main surface; a functional unit having an arbitrary pattern; a first wiring portion drawn out from one of both ends of the functional portion; a second wiring portion drawn out from the other of the two ends of the functional portion; a circuit extending from the first wiring portion and the second wiring portion to a side opposite to the functional portion, partially overlapping the first electrode pad and the second electrode pad, respectively, and having a first end portion constituting a first misalignment absorbing region and having a first bent portion, and a second end portion constituting a second misalignment absorbing region and having a second bent portion; a circuit forming process in which the functional section, the first wiring section, the second wiring section, and portions of the first end section and the second end section that do not overlap with the first electrode pads and the second electrode pads are embedded in the first main surface of the film using an ultrasonic welding machine; a connecting step of electrically connecting the first electrode pads and the second electrode pads to the thin metal wires located on the first electrode pads and the second electrode pads, respectively; the ultrasonic welding machine includes a horn that applies ultrasonic vibrations to melt a contact surface of the film with the thin metal wire and embed the thin metal wire in the first main surface of the film, and the thin metal 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 misalignment absorption region and the second misalignment absorption region are respectively composed of the first end and the second end in a bent shape connected by the first bent portion and the second bent portion, and each have a width that absorbs misalignment in the first direction between the first electrode pad and the second electrode pad and the circuit, the first bent portion and the second bent portion are embedded in the first main surface, and thin metal wires overlapping the first electrode pad and the second electrode pad contact upper surfaces of the first electrode pad and the second electrode pad, respectively. A method for manufacturing a circuit-embedded substrate.

2. The method for manufacturing a circuit-embedded substrate according to claim 1 , wherein the bent shape is a zigzag shape or a U-shape in plan view.

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