Method for manufacturing circuit embedded board

Abstract

[Problem] To provide a method for manufacturing a circuit-embedded substrate capable of improving yield by improving alignment accuracy between a circuit and an electrode pad. [Solution] The method comprises: a film preparation step; arranging two electrode pads on the thin film along the first direction; a step for embedding the thin film using an ultrasonic welding machine to form a circuit comprising a single thin metal wire and having a functional part having an arbitrary pattern, two wiring parts drawn from both ends of the functional part, and two end parts extending from the wiring parts to the opposite side from the functional part and partially overlapping the electrode pads to constitute two positional shift absorbing regions; and a step for connecting the electrode pad and the thin metal wire on the electrode pad, the ultrasonic welding machine having: a welding head for embedding the thin metal wire into the thin film by melting a contact surface of the thin film with the thin metal wire by ultrasonic vibration; and a fine metal wire led out through the inside thereof, and the positional shift absorbing region is composed of a curved end portion and has a width that absorbs positional shift between the electrode pad and the circuit in the first direction.

Description

Technical Field

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

[0002] A thin film heater in which a single metal thin wire is embedded in a thin film in an arbitrary pattern is known (for example, see Patent Document 1). Figure 10 Such a thin film heater 100 comprises: a thin film 200; a quadrilateral first electrode pad 500 and a second electrode pad 600, which are arranged parallel to each other at intervals along the Y direction at the periphery of the thin film 200; and a circuit 400, which is composed of a metal thin wire 300 embedded in the thin film 200.

[0003] Circuit 400 includes a heater portion 450 having an arbitrary pattern; first and second wiring portions 430 and 440 extending from opposite ends of heater portion 450; and first and second end portions 410 and 420 extending from first and second wiring portions 430 and 440 respectively toward the side opposite to heater portion 450 (the +X direction in the figure) and overlapping first and second electrode pads 500 and 600, respectively. Circuit 400 is embedded by applying ultrasonic vibrations using an ultrasonic welding machine to melt the contact surface of film 200 with metal wires 300. For example, the circuit can be embedded sequentially from first end portion 410, followed by first wiring portion 430, heater portion 450, second wiring portion 440, and second end portion 420.

[0004] The first end portion 410 and the second end portion 420 extend across 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 metal thin wire 300, which is in contact with the upper surfaces of the first end portion 410 and the second end portion 420. When a voltage is applied to the first electrode pad 500 and the second electrode pad 600, a current flows through the circuit 400, causing the heater portion 450 to generate heat.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Publication No. 2022-066706 Summary of the Invention

[0008] Technical problem to be solved by the invention

[0009] In the existing method for manufacturing the thin film heater 100, the electrode pads 500 and 600 are first arranged on the thin film 200, and the film 200 is set so that the corners thereof touch a jig (not shown). Thereafter, the metal wire 300 is embedded into the thin film 200 in such a manner that the first end 410 and the second end 420 overlap with the electrode pads 500 and 600. Since the arrangement of the electrode pads 500 and 600 and the embedding of the metal wire 300 are different processes, the following positional offsets will occur. That is, (1) positional offset of the electrode pads, (2) positional offset of the embedding of the metal wires, and (3) positional offset of the embedding of the electrode pads and the metal wires. In this manufacturing method, for example, if the arrangement position of the electrode pads 500 and 600 is toward Figure 10 The +Y direction of (a) is offset, and the embedded position of the metal thin wire 300 is relatively Figure 10 That is, in the conventional manufacturing method, since it is difficult to align the electrode pads 500 and 600 with the circuit 400 , there is a problem that it is difficult to increase the yield.

[0010] The present invention has been made to solve the above-mentioned technical problems, and an object of the present invention is to provide a method for manufacturing a circuit-embedded substrate capable of improving the yield rate by enhancing the alignment accuracy between the circuit and the electrode pad.

[0011] Technical solutions to technical problems

[0012] A first invention to achieve the above-mentioned object is a method for manufacturing a circuit-embedded substrate, comprising:

[0013] Preparation process, preparing the film;

[0014] an arranging step of arranging the first electrode pad and the second electrode pad in parallel with each other at a distance from each other along the first direction on the peripheral portion of the first main surface of the film;

[0015] A circuit forming process, using an ultrasonic welding machine to embed the functional portion, the first wiring portion and the second wiring portion, and the portions of the first end portion and the second end portion that do not overlap with the first electrode pad and the second electrode pad into the first main surface of the film to form a circuit, the circuit being composed of a metal fine wire arranged on the first main surface and having: a functional portion having an arbitrary pattern; a first wiring portion extending from one of the two ends of the functional portion; a second wiring portion extending from the other of the two ends of the functional portion; and a first end portion and a second end portion extending from the first wiring portion and the second wiring portion to the side opposite to the functional portion, respectively, and partially overlapping with the first electrode pad and the second electrode pad, respectively, the first end portion constituting a first position shift absorbing region, and the second end portion constituting a second position shift absorbing region; and

[0016] The connecting step is to electrically connect the first electrode pad and the second electrode pad to the metal thin wire located on the first electrode pad and the second electrode pad respectively.

[0017] The ultrasonic welding machine comprises: a welding head, which melts the contact surface of the film and the metal wire by applying ultrasonic vibration and embeds the metal wire into the first main surface of the film; and a metal wire, which passes through the interior of the welding head and is continuously led out from the front end of the welding head to the first main surface of the film.

[0018] The first and second positional deviation absorbing regions are formed by first and second ends of the bent shape and have widths sufficient to absorb positional deviations between the first and second electrode pads and the circuit in the first direction.

[0019] According to this manufacturing method, even if the first and second electrode pads are offset relative to the first and second end portions in the first direction, the first and second end portions are curved and have widths sufficient to accommodate the positional offset between the first and second electrode pads and the circuit in the first direction. Therefore, the first and second end portions each have overlapping portions with the first and second electrode pads. This improves the alignment accuracy between the electrode pads and the circuit, thereby increasing the yield rate.

[0020] In the circuit-embedded substrate manufacturing method according to the second invention, in the first invention, the curved shape is a zigzag shape or a U-shape in a plan view.

[0021] Effects of the Invention

[0022] According to the method for manufacturing a circuit embedded substrate of the present invention, the alignment accuracy between the circuit and the electrode pad can be improved, thereby achieving an improvement in the yield rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a schematic perspective view showing one embodiment of a method for manufacturing a circuit-embedded substrate.

[0024] Figure 2 It is a partially enlarged view showing an example of the first end portion and the second end portion.

[0025] Figure 3 This is an enlarged view showing a state where the electrode pad is positionally shifted in the +X direction.

[0026] Figure 4 It is a partially enlarged view showing another example of the first end portion and the second end portion.

[0027] Figure 5 This is an enlarged view showing a state where the electrode pad is positionally shifted in the +X direction.

[0028] Figure 6 The electrode pads are shown from Figure 5 This is an enlarged view showing a state where the position is further shifted in the +X direction.

[0029] Figure 7 This is an enlarged view showing a state where the electrode pad is positionally displaced in the -X direction.

[0030] Figure 8 This is an enlarged view showing a state in which an electrode pad is positionally displaced in the +X direction in a conventional thin film heater.

[0031] Figure 9 This is an enlarged view showing a state in which an electrode pad is positionally displaced in the -X direction in a conventional thin film heater.

[0032] Figure 10 (a) is a schematic plan view showing a conventional thin film heater. Figure 10 (b) is Figure 10 (a) AA cross-sectional view. DETAILED DESCRIPTION

[0033] (Overview of circuit-embedded substrates)

[0034] Reference Figure 1 (f), the circuit is embedded (buried) in a substrate 1 having a thin film 2, a circuit 4 consisting of a thin metal wire 3 arranged on the first main surface 2a of the thin film 2, a first electrode pad 5, and a second electrode pad 6. The circuit 4 has 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 extended from one end 45a of the functional portion 45. The second wiring portion 44 is extended from the other end 45b of the functional portion 45. The first end portion 41 extends from the first wiring portion 43 to the side opposite to the functional portion 45 (-Y direction) and overlaps with the first electrode pad 5. The second end portion 42 extends from the second wiring portion 44 to the side opposite to the functional portion 45 (-Y direction) and overlaps with the second electrode pad 6.

[0035] In the present embodiment, the first end portion 41 and the second end portion 42 have a sawtooth shape (an example of a curved shape) in a plan view.

[0036] The functional portion 45, first wiring portion 43, and second wiring portion 44 are embedded in the first principal surface 2a of the film 2. The portions of the first end portion 41 and second end portion 42 that overlap with the electrode pads 5 and 6 are not embedded in the first principal surface 2a, while the remaining portions are embedded in the first principal surface 2a. In other words, the thin metal wires 3 located above the electrode pads 5 and 6 are not embedded in the first principal surface 2a, while the thin metal wires 3 not located above the electrode pads 5 and 6 are embedded in the first principal surface 2a.

[0037] In this embodiment, the functional portion 45 is a heating portion, and the circuit embedded in the substrate 1 is a thin film heater. For example, by applying a positive voltage to the first electrode pad 5 and a negative voltage to the second electrode pad 6, a current is generated in the circuit 4 formed by the metal thin wire 3, and the functional portion 45 generates heat. The functional portion 45 has two ends 45a and 45b connected to the first wiring portion 43 and the second wiring portion 44, respectively, and has a ring-shaped pattern shape. More specifically, the functional portion 45 has the following pattern shape: after extending from the connection portion 45a with the first wiring portion 43 in the +X direction, it extends in the +Y direction, the -X direction, and the -Y direction, and then extends in the +X direction to reach the connection portion 45b with the second wiring portion 44. In this way, the functional portion 45 has connection portions 45a and 45b with the first wiring portion 43 and the second wiring portion 44, and has an arbitrary pattern extending from the connection portions 45a and 45b in the XY plane.

[0038] The film 2 can be formed into any shape, and in this embodiment, is rectangular. The film 2 can be made of a transparent, opaque, or colored transparent film. As the material of the film 2, for example, thermoplastic resins such as ethylene resins, propylene resins, polyolefin resins, thermoplastic polyester resins, polyamide resins, polyvinyl chloride, polycarbonate, and ABS resin can be used. It can also contain two or more of these. Inorganic fine powders or organic fillers, dispersants, antioxidants, compatibilizers, ultraviolet stabilizers, anti-blocking agents, antistatic agents, etc. can be appropriately added to the film 2. The thickness of the film 2 is, for example, 0.05 mm to 1 mm.

[0039] The metal wire 3 can be made of a conductive material such as copper, iron, gold, copper-nickel, nickel-chromium, or iron-nickel-chromium. From the perspectives of electrical resistance, durability, and cost, copper or a copper alloy obtained by combining copper with zinc, lead, tin, silver, aluminum, nickel, beryllium, zirconium, or the like, alone or in combination, is preferred. The diameter of the metal wire 3 is, for example, 0.01 mm to 0.5 mm. If the diameter is minimized, for example, 0.01 mm to 0.2 mm, the metal wire 3 can be made less conspicuous.

[0040] It should be noted that circuit 4 can also be formed by a conductive wire composed of a thin metal wire 3 and an insulating coating. The insulating coating is 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.

[0041] The two electrode pads 5 and 6 can be made of a conductive material such as copper, phosphor bronze, brass, Corson alloy, nickel, or molybdenum. Alternatively, a base material made from these materials and plated with nickel, tin, gold, silver, copper, or the like can be used. The electrode pads 5 and 6 are, for example, 5 mm x 10 mm in size and 0.1 mm in thickness.

[0042] It should be noted that, although the electrode pads 5 and 6 are quadrilateral in this embodiment, they are not limited thereto and may be, for example, polygonal shapes other than quadrilaterals, circular shapes, elliptical shapes, L-shaped shapes, etc.

[0043] (Method for manufacturing circuit-embedded substrate)

[0044] Reference Figure 1 An embodiment of a method for manufacturing such a circuit-embedded substrate 1 will be described.

[0045] The method for manufacturing the circuit embedded substrate 1 comprises: a preparation step (not shown) of preparing the film 2; a placement step ( Figure 1 (a)), the first electrode pad 5 and the second electrode pad 6 are arranged on the peripheral portion of the first main surface 2a of the film 2; circuit forming step ( Figure 1 (b)~ Figure 1 (e)), forming the circuit 4 using an ultrasonic welding machine 7; and a connection step ( Figure 1 (f) ), the first end 41 and the second end 42 of the circuit 4 are electrically connected to the electrode pads 5 and 6 .

[0046] In the preparation step, it is best to fix the film 2 on a workbench (not shown). In addition, a clamp (not shown) can also be used to facilitate the alignment of the film 2. In the arrangement step, the first electrode pad 5 and the second electrode pad 6 are arranged on the peripheral portion of the first main surface 2a of the film 2. In other words, they are arranged side by side in the X direction along a side of the film 2 parallel to the X direction (first direction). The two electrode pads 5 and 6 are square in shape and are arranged parallel to each other at a distance along the X direction. The two electrode pads 5 and 6 respectively become the terminal portions of the circuit embedded substrate 1. The two electrode pads 5 and 6 can be fixed to the first main surface 2a using, for example, an adhesive.

[0047] Reference Figure 1(b) The ultrasonic welding machine 7 used in the circuit formation step includes an oscillator (not shown) that generates ultrasonic vibrations; a horn 71 that transmits the ultrasonic vibrations from the oscillator; and a thin metal wire 3. The horn 71 applies ultrasonic vibrations to melt the contact surface of the film 2 with the thin metal wire 3 and embed the thin metal wire 3 into the first principal surface 2a of the film 2. The thin metal wire 3 passes through the interior of the horn 71 and is continuously drawn out from the front end 71a of the horn 71 onto the first principal surface 2a of the film 2.

[0048] In the circuit forming process, first, Figure 1 As shown in (b), while the metal wire 3 is led out from the welding head 71 to a predetermined length, the metal wire 3 is embedded in the first main surface 2a of the film 2 and straddles the first electrode pad 5 in a zigzag shape to form a first end portion 41. At this time, the zigzag-shaped bent portion is embedded in the first main surface 2a, and the metal wire 3 overlapping the first electrode pad 5 is not embedded in the first main surface 2a but contacts the upper surface of the first electrode pad 5.

[0049] Then, if Figure 1 As shown in (c), the metal wire 3 is led out to a predetermined length from the embedded terminal of the first end portion 41 toward the +Y direction, and the metal wire 3 is embedded in the first main surface 2a to form a first wiring portion 43. Next, the metal wire 3 is led out to a predetermined length from the embedded terminal 43a of the first wiring portion 43, and the metal wire 3 is embedded in the first main surface 2a in an arbitrary pattern extending in the XY plane to form a functional portion 45. The embedded terminal 43a of the first wiring portion 43 becomes the starting end of the functional portion 45. In other words, the terminal 43a of the first wiring portion 43 becomes one of the two ends 45a of the functional portion 45 (refer to Figure 1 (d)).

[0050] Then, if Figure 1 As shown in (d), while a predetermined length of the thin metal wire 3 is drawn out from the welding head 71, the thin metal wire 3 is extended from the terminal end 45b of the functional portion 45 in the -Y direction and embedded in the first main surface 2a to form the second wiring portion 44. The terminal 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.

[0051] Then, if Figure 1As shown in (e), the metal wire 3 is led out to a predetermined length from the embedded terminal 44a of the second wiring portion 44, while being embedded in the first main surface 2a and crossing over the second electrode pad 6 in a zigzag shape to form the second end portion 42. At this time, the zigzag-shaped bent portion is embedded in the first main surface 2a, and the metal wire 3 overlapping the second electrode pad 6 is not embedded in the first main surface 2a but contacts the upper surface of the second electrode pad 6. After the second end portion 42 is formed, the metal wire 3 is cut at the embedded terminal of the second end portion 42. As a cutting method, for example, a cutter or pliers can be used.

[0052] Finally, in the connection process, Figure 1 As shown at point P in (f), the two electrode pads 5 and 6 are electrically connected to the metal wire 3 located above (in contact with the upper surface) the two electrode pads 5 and 6. The connection can be made using welding (resistance welding, ultrasonic welding, laser welding, etc.), soldering, brazing, etc., which are well-known metal joining techniques. It should be noted that the electrode pads 5 and 6 can be electrically connected to the metal wire 3 at multiple locations.

[0053] In this way, the circuit-embedded substrate 1 can be obtained.

[0054] (First embodiment of the positional deviation absorbing region)

[0055] Reference Figure 2 The first end portion 41 and the second end portion 42 constitute a first positional misalignment absorbing region 41a and a second positional misalignment absorbing region 42a, respectively. The first positional misalignment absorbing region 41a and the second positional misalignment absorbing region 42a are regions indicated by dotted lines in the figure. Figure 2 The diagram shows a state in which there is no positional deviation between the first electrode pad 5 and the second electrode pad 6 and the first end portion 41 and the second end portion 42 .

[0056] The first positional deviation absorbing region 41a has a width W 41 The second position deviation absorbing region 42a has a width W 42 These widths W 41 、W 42 The width of the zigzag shape of the end portions 41 and 42 is equal to the width W5 and W6 of the two electrode pads 5 and 6. Of course, if the width W of the position deviation absorbing regions 41a and 42a is increased, 41 、W 42 , the size of the allowable positional deviation of the electrode pads 5 and 6 in the X direction will also increase.

[0057] For example, when the widths W5 and W6 of the electrode pads 5 and 6 are 5 mm respectively and the interval S between the electrode pads 5 and 6 is 10 mm, the width W 41 、W42 Can be 15mm respectively.

[0058] like Figure 3 As shown, for example, even when the electrode pads 5 and 6 are arranged to be shifted by d in the +X direction, the position shift absorbing regions 41a and 42a each have a width W greater than d. 41 、W 42 , so it is also possible to absorb the positional deviation of the electrode pads 5 and 6. The positional deviation absorbing regions 41a and 42a each have a width W 41 、W 42 Even if the positions of electrode pads 5 and 6 relative to film 2 are offset by d in the X direction, ends 41 and 42 still overlap with electrode pads 5 and 6. Therefore, the embedding positions of ends 41 and 42 do not need to take into account the positional offset of electrode pads 5 and 6. In other words, each time the circuit-embedded substrate 1 is manufactured, ends 41 and 42 can be embedded in the same position each time.

[0059] In this manner, since the end portions 41 and 42 can be aligned with the electrode pads 5 and 6 without taking into account the positional deviation of the electrode pads 5 and 6 , the yield rate can be improved.

[0060] (Second embodiment of the positional deviation absorbing region)

[0061] Reference Figure 4 The curved shape of the first end portion 41 and the second end portion 42 may be U-shaped in a plan view. The first end portion 41 and the second end portion 42 constitute a first positional deviation absorbing region 41 a and a second positional deviation absorbing region 42 a , respectively. Figure 4 The diagram shows a state in which there is no positional deviation between the first electrode pad 5 and the second electrode pad 6 and the first end portion 41 and the second end portion 42 .

[0062] The first positional deviation absorbing region 41a has a width W 41 The second position deviation absorbing region 42a has a width W 42 These widths W 41 、W 42 The width of the U-shaped ends 41 and 42 is equal to each other, and the following equations (1) and (2) are satisfied respectively. Here, S5 and S6 are the intervals between two metal thin wires 3 that span the electrode pads 5 and 6 in the Y direction, respectively.

[0063] W 41 = (2 × W3) + S5… (1)

[0064] W 42 = (2 × W3) + S6… (2)

[0065] Furthermore, when ultrasonically welding the metal thin wire 3 and the electrode pads 5 and 6, the width W of each of the first positional deviation absorbing region 41a and the second positional deviation absorbing region 42a can be set to 41 、W 42 The widths W5 and W6 of the two electrode pads 5 and 6 are set to be equal. It should be noted that when soldering the metal wire 3 and the electrode pads 5 and 6, it is necessary to place the solder on both sides of the metal wire 3 (in other words, place the solder at a position sandwiching the metal wire 3) to fix the metal wire 3, so W5 (W6)>W 41 (W 42 ).

[0066] The width (diameter) W3 and the intervals S5 and S6 of the metal thin wires 3 are set to values ​​satisfying the following equations (3) and (4), respectively, with respect to the widths W5 and W6 of the electrode pads 5 and 6 .

[0067] W5=2W3+S5…(3)

[0068] W6=2W3+S6…(4)

[0069] That is, if the widths W5 and W6 of the electrode pads 5 and 6 and the width (diameter) W3 of the metal wire 3 are determined, the spacings S5 and S6 are calculated using the above equations (3) and (4). For example, when using electrode pads 5 and 6 with a width W5 (= width W6) of 5 mm and a metal wire 3 with a width (diameter) W3 of 0.5 mm, the spacing S5 (= S6) is 5-1 = 4 mm.

[0070] In this way, the first positional deviation absorbing region 41a and the second positional deviation absorbing region 42a are formed in a U-shape by separating the intervals S5 and S6. For example, Figure 5 As shown, even when electrode pads 5 and 6 are offset in the +X direction by d (= W5 / 2 = W6 / 2), there are still portions where thin metal wires 3 overlap with electrode pads 5 and 6 (portions where thin metal wires 3 cross electrode pads 5 and 6). This means that the alignment accuracy between electrode pads 5 and 6 and end portions 41 and 42 is improved, thereby improving the yield rate.

[0071] In addition, if Figure 6 and Figure 7 As shown, even if the electrode pads 5 and 6 are offset by d+d / 2 in the ±X direction, as long as the shapes of the first end 41 and the second end 42 satisfy the above equations (3) and (4), there will be overlapped portions of the metal wire 3 and the electrode pads 5 and 6. Figure 6 and Figure 7 In the figure, a metal thin wire 3 overlaps with the edge of the electrode pads 5 and 6. Figure 6 and Figure 7 It can be seen that the allowable range of positional deviation of the electrode pads 5 and 6 in the X direction is d+d / 2. Here, since d=W5 / 2 (=W6 / 2), W5 / 2+W5 / 4=3W5 / 4 (=3W6 / 4).

[0072] On the other hand, refer to Figure 8 and Figure 9 , the first end portion 410 and the second end portion 420 of the conventional thin film heater 100 are straight lines. Figure 8 and Figure 9 In FIG, although the electrode pads 500 and 600 are offset in the X direction, there are portions where the metal thin wires 300 and the electrode pads 500 and 600 overlap. Figure 8 and Figure 9 The offset of the electrode pads 500 and 600 is half the width of the electrode pads 500 and 600 (W 500 / 2,W 600 / 2). That 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).

[0073] By changing the shape of first end portion 41 and second end portion 42 from the conventional straight line to a U-shape satisfying equations (3) and (4), the allowable range of positional deviation of electrode pads 5 and 6 in the X direction is increased by 1.5 times. This means that alignment of first end portion 41 and second end portion 42 with electrode pads 5 and 6 is facilitated, thereby improving the yield rate.

[0074] It should be noted that although the above two embodiments are methods in which the embedded position of the metal thin wire 3 is not shifted while the position of the electrode pads 5 and 6 is shifted, even if, on the contrary, the electrode pads 5 and 6 are not shifted while the embedded position of the metal thin wire 3 is shifted, the manufacturing method of the present invention can achieve the same effects as the above embodiments. In addition, even if the positions of the electrode pads 5 and 6 and the embedded position of the metal thin wire 3 are both shifted, the manufacturing method of the present invention can achieve the same effects as the above embodiments.

[0075] Description of Reference Numerals

[0076] 1: Circuit embedded in substrate; 2: Film; 2a: First main surface; 3: Metal wire; 4: Circuit; 41: First end portion; 41a: First position offset absorption region; 42: Second end portion; 42a: Second position offset absorption region; 43: First wiring portion; 44: Second wiring portion; 45: Functional portion; 5: First electrode pad; 6: Second electrode pad; 7: Ultrasonic welding machine; 71: Welding head; 100: Thin film heater; 200: Thin film; 300: Metal wire; 400: Circuit; 410: First end portion; 420: Second end portion; 430: First wiring portion; 440: Second wiring portion; 450: Heater portion; 500: First electrode pad; 600: Second electrode pad; 700: Adhesive layer.

Claims

1. A method for manufacturing a circuit-embedded substrate, comprising: Preparation process, preparing the film; an arranging step of arranging the first electrode pad and the second electrode pad in parallel with each other at a distance from each other along a first direction on a peripheral portion of the first main surface of the film; A circuit forming process, using an ultrasonic welding machine to embed the functional part, the first wiring part and the second wiring part, and the parts of the first end part and the second end part that do not overlap with the first electrode pad and the second electrode pad into the first main surface of the film to form a circuit, the circuit being composed of a metal thin wire arranged on the first main surface and having: the functional part having an arbitrary pattern; the first wiring part being led out from one of the two ends of the functional part; the second wiring part being led out from the other of the two ends of the functional part; and the first end part and the second end part respectively extending from the first wiring part and the second wiring part to the side opposite to the functional part and respectively partially overlapping with the first electrode pad and the second electrode pad, the first end part constituting a first position deviation absorption region, and the second end part constituting a second position deviation absorption region; and a connecting step of electrically connecting the first electrode pad and the second electrode pad to the metal thin wire located on the first electrode pad and the second electrode pad, respectively; The ultrasonic welding machine has: a welding head that applies ultrasonic vibration to melt the contact surface of the film with the metal thin wire and embeds the metal thin wire into the first main surface of the film; and The metal thin wire passes through the interior of the welding head and is continuously led out from the front end of the welding head to the first main surface of the film. The first and second positional misalignment absorbing regions are formed by the first and second curved ends and have widths sufficient to absorb positional misalignment between the first and second electrode pads and the circuit in the first direction.

2. The method for manufacturing a circuit-embedded substrate according to claim 1, wherein: The curved shape is a sawtooth shape or a U shape when viewed from above.

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