JP4936457B2 - Bump structure and manufacturing method thereof - Google Patents

Abstract

A bump structure (30) is provided with a section (32), which is formed of a conductive material and is held by a circuit board (40) by penetrating the circuit board (40) in the thickness direction, and a protruding section (31) which protrudes outward from at least one surface of the circuit board (40). The protruding section (31) is provided with a base section (33), which is positioned on the front surface side of the circuit board (40) and has a prescribed diameter or width and a prescribed height, and a leading end section (34), which is formed on a base section (33) on the side opposite to the circuit board (40) and has maximum diameteror width larger than the prescribed diameter or width. Since the section (32) is held by being embedded in the circuit board (40), bonding strength between the bump structure (30) and the circuit board (40) is improved compared with that in conventional constitution wherein such holding section is formed on the conductor pattern of the circuit board.

Description

  The present invention relates to a bump structure including a columnar protruding piece projecting in a direction orthogonal to the one surface on at least one surface side of a substrate, and a manufacturing method thereof.

  Conventionally, as this type of bump structure 30, as shown in FIG. 7 (e), the base end of the protruding piece 31 is so thick that the head 34 on the front end side is thicker than the neck 33 on the base end side of the protruding piece 31. What was formed in the thickness from which the side differs from the front end side is known. The bump structure 30 is generally formed on a conductor pattern 42 formed on the surface of the substrate 40, and is supported with respect to the substrate 40 by being bonded to the conductor pattern 42.

  Below, the manufacturing method of the bump structure 30 of FIG.7 (e) is demonstrated. As shown in FIG. 7A, a resist 51 is formed on the back surface (lower surface in FIG. 7A) side of the substrate 40 (back surface resist forming step). In this example, the conductor patterns 42 are formed on both surfaces of the substrate 40, and the conductor patterns 42 provided on both surfaces of the substrate 40 are electrically connected to each other by forming an electric circuit in the through holes 41 penetrating the substrate. is doing. Here, an opening 57 for energization that exposes a part of the conductor pattern 42 is formed in the resist 51. Thereafter, as shown in FIG. 7B, a resist 52 is formed on the front surface of the substrate 40 (front-side resist forming step). As the resist 52, a positive photosensitive resist that can be patterned into a desired shape by exposure and development is used. That is, if light is irradiated after laminating a mask 59 having an opening 58 as shown in FIG. 7B on the resist 52, only a portion of the resist 52 irradiated with light from the opening 58 of the mask 59 is exposed. It can be removed by subsequent development. In the front resist formation step, a neck molding hole 53 is formed in the resist 52 so as to open in a circular shape and expose a part of the conductor pattern 42. Here, a resist having a thickness larger than that of the resist 51 on the back side is used as the resist 52 on the front side.

After the front side resist formation step, by performing electroplating in a state where the conductor pattern 42 is energized through the above-described energization opening 57, the conductor pattern 42 exposed through the neck molding hole 53 as shown in FIG. Metal material 30 'is deposited (projection piece formation process). In the projecting piece forming step, as shown in FIG. 7 (d), the neck portion forming hole 53 is filled with a metal material 30 'to form the neck portion 33 of the projecting piece 31, and the electroplating is continued to form the neck portion forming hole. A head portion 34 of the protruding piece 31 is formed outside 53. In the subsequent resist stripping step, the resist 52 is removed as shown in FIG. 7E (see, for example, Patent Document 1).
JP-A-6-310514

  By the way, in recent years, as described above, there is a demand for improving the bonding strength with the substrate 40 for the bump structure 30 having the protruding pieces 31 having different thicknesses at the neck 33 and the head 34. For example, it is considered to use the bump structure 30 as a connector for connecting circuit boards to each other, and there is a demand for improving the coupling strength when the connector is put to practical use. Specifically, in a connector having a header and a socket that can be attached to and detached from each other, the bump structure 30 is adopted as a header contact provided in the header, and the head 34 of the protruding piece 31 is attached to the socket contact provided in the socket. By locking, the header and the socket can be mechanically coupled and electrically connected. In this case, an excessive external force can be applied to the bump structure 30 when the header and the socket are attached / detached. Therefore, it is desired to improve the bonding strength between the bump structure 30 and the substrate 40 that supports the bump structure 30.

  The present invention has been made in view of the above reasons, and an object of the present invention is to provide a bump structure having improved bond strength with a substrate as compared with the conventional structure and a method for manufacturing the same.

The invention according to claim 1 is a columnar bump structure made of a conductive material, and a support piece supported by the substrate by penetrating the substrate in the thickness direction, and protruding from the support piece on at least one surface side of the substrate and a projecting piece which, projecting pieces are formed in a different thickness and the proximal end side and distal end side so that the distal end side of the head from the neck of the proximal side becomes thick, the support piece, the inner peripheral It is provided in a through-hole with through-hole plating on the surface and is connected to the through-hole plating. The through-hole plating has flange portions protruding on both sides in the thickness direction of the substrate. It is characterized by sandwiching .

  According to this invention, the bump structure includes a support piece supported by the substrate by penetrating the substrate in the thickness direction and a protruding piece protruding from the support piece on at least one surface side of the substrate. The support piece is embedded in the substrate, and the bonding strength with the substrate is improved as compared with the conventional configuration formed on the conductor pattern formed on the surface of the substrate.

  The invention of claim 2 is characterized in that, in the invention of claim 1, the protruding pieces are respectively formed on both sides in the thickness direction of the substrate.

  According to the present invention, since the protrusions are provided on both sides in the thickness direction of the substrates, when this bump structure is used for a connector for connecting circuit substrates, for example, the circuit substrates provided on both sides of the substrates are mechanically connected to each other. It can be coupled and electrically connected.

  Invention of Claim 3 is a manufacturing method of the bump structure of Claim 1 or Claim 2, Comprising: It has a through hole penetrating in the thickness direction, and the inner peripheral surface of the through hole is made of the conductive material. Forming a first resist having a neck molding hole for exposing a through hole on a surface of the substrate on which the protruding piece is to be formed, using the substrate on which the underlying layer is formed; and resist After the forming process, plating is performed and the support material is formed by filling the through hole with the conductive material, and after the support piece forming process, plating is performed and the neck portion molding hole is filled with the conductive material. Forming the neck portion, and further continuing the plating to form the head portion outside the neck molding hole, and the resist stripping process for stripping the resist after the projecting piece forming step. Characterized by a step.

  According to this invention, in the protruding piece forming step, the portion filled in the neck forming hole of the first resist becomes the neck portion of the protruding piece, and the portion formed outside the neck forming hole is the head of the protruding piece. Therefore, the neck can be formed in a desired shape according to the thickness dimension of the first resist and the design of the opening shape of the neck forming hole.

  According to a fourth aspect of the present invention, in the third aspect of the present invention, in the resist forming step, a second resist having a head molding hole larger than the neck molding hole is disposed in the neck molding hole. The first resist is stacked so as to fit.

  According to the present invention, in the protruding piece forming step, the head formed outside the neck molding hole is accommodated in the head molding hole, so that the spread of the head is regulated by the opening shape of the head molding hole. Is done. Therefore, the head can be formed in a desired shape according to the design of the opening shape of the head molding hole.

  According to the present invention, since the support piece, which is a part of the bump structure, is embedded in the substrate, the bonding strength with the substrate is higher than that of the conventional configuration formed on the conductor pattern formed on the surface of the substrate. There is an effect of improving.

  The bump structure shown in each of the following embodiments is used for a connector that mechanically couples and electrically connects a pair of circuit boards arranged so that at least a part of the surface faces each other. is there. Hereinafter, the configuration and function of the connector will be described.

  As shown in FIG. 2, this connector includes a header 1 provided on a first circuit board and a socket 2 provided on a second circuit board (not shown). The header 1 has a header contact 3 made of a conductive material and a header body 4 made of an insulating material and supporting the header contact 3, and the socket 2 is made of a conductive material and can be electrically connected to the header contact 3. And a socket body 6 made of an insulating material and supporting the socket contact 5. A bump structure shown in each of the following embodiments is used as the header contact 3. Here, an example is shown in which the header body 4 is formed integrally with the first circuit board (that is, the first circuit board also serves as the header body 4). However, the header 1 is different from the first circuit board. You may have the header body 4 formed in the body. In the following description, it is assumed that the thickness direction of the circuit board is the front-rear direction, and the second circuit board provided with the socket 2 is arranged on the front side of the first circuit board provided with the header 1.

  As shown in FIG. 2A, the header contact 3 includes a columnar protruding piece 7 that protrudes forward on the front side of the header body 4. The protruding piece 7 is formed in a so-called mushroom shape in which the distal end head portion 9 is thicker than the proximal end neck portion 8. As shown in FIG. 2 (a), the socket contact 5 has a thickness dimension equal to or smaller than the height dimension of the neck portion 8, and has both longitudinal end portions so as to leave a gap larger than the height dimension of the head portion 9 behind. A connection piece 17 supported by the socket body 6 is provided. The connecting piece 17 includes a pair of spring pieces 20 that form a slit 21 having a width dimension equal to or smaller than the thickness of the neck portion 8 between the connecting pieces 17. The connecting piece 17 is formed with introduction holes 22 that are continuous with the slit 21 at both ends in the longitudinal direction of the slit 21 and have dimensions that allow the head 9 to be inserted and removed. The pair of spring pieces 20 have flexibility in the width direction of the slit 21 and elastically contact the neck portion 8 when the protruding piece 7 is inserted into the slit 21 through the introduction hole 22. A plurality of header contacts 3 and socket contacts 5 (22 in the illustrated example) are provided, and are arranged at positions corresponding to each other. In addition, the socket contact 5 has a terminal piece 18 for soldering that protrudes from both end surfaces in the width direction of the socket body 6 and the connection piece 17 in an integrated manner.

  Further, around the area where the header contact 3 is provided in the header body 4, a cylindrical guide protrusion 12 protruding forward on the front side of the header body 4 is provided in the same manner as the protrusion piece 7. The guide protrusion 12 has a base end side small diameter portion 13 formed thicker than the neck portion 8 of the protrusion piece 7 and a distal end side large diameter portion 14 formed thicker than the small diameter portion 13. In the socket body 6, at a position corresponding to the guide protrusion 12 of the header body 4, a guide receiving portion 24 through which a guide long hole 23 is provided is provided. The guide long hole 23 has a width 27 that is equal to or greater than the thickness (diameter) of the small-diameter portion 13 of the guide protrusion 12 and less than the thickness (diameter) of the large-diameter portion 14, and the guide protrusion 12. And an inlet 28 having a width dimension equal to or larger than the thickness (diameter) of the large-diameter portion 14. Here, the guide long hole 23 is arranged such that the guide protrusion 12 is inserted into the large diameter portion 14 in a state where the protrusion piece 7 of the header 1 is inserted into the introduction hole 22 of the socket 2.

  A method of attaching / detaching the header 1 to / from the socket 2 in the connector having the above-described configuration will be described.

  In this connector, the header 1 is attached to and detached from the socket 2 using the guide protrusion 12 and the guide receiving portion 24 as a guide. That is, when the header 1 and the socket 2 are overlapped in the thickness direction of the circuit board in a state where the guide protrusion 12 is aligned with the introduction port 28 of the guide long hole 23, the guide is guided from the introduction port 28 of the guide long hole 23. The protrusion 12 is inserted into the guide long hole 23, and at this time, the protrusion piece 7 is inserted into one introduction hole 22. Further, from this state, if the header 1 is moved relative to the socket 2 so that the guide protrusion 12 moves to the locking portion 27 in the guide slot 23, as shown in FIG. In addition, the small-diameter portion 13 of the guide protrusion 12 can be inserted into the engaging portion 27 of the guide long hole 23. At this time, the protrusion piece 7 is in the state where the neck portion 8 is inserted into the slit 21. .

  In a state where the neck portion 8 of the protruding piece 7 is inserted into the slit 21, the head portion 9 of the protruding piece 7 engages with both sides (spring pieces 20) of the connecting piece 17 so that the protruding piece 7 comes out of the slit 21. The header 1 and the socket 2 are mechanically coupled to each other. Furthermore, the large-diameter portion 14 of the guide projection 12 is engaged with both sides of the guide long hole 23 in the guide receiving portion 24 so that the guide protrusion 12 is prevented from being detached from the guide long hole 23, thereby the header 1 and the socket 2. The mechanical coupling between the two is assisted. In addition, since the spring pieces 20 on both sides of the slit 21 are in elastic contact with the neck portion 8, contact pressure between the header contact 3 and the socket contact 5 is ensured. Further, the header 1 can be moved relative to the socket 2 so that the guide protrusion 12 moves from the state where the neck portion 8 of the protrusion piece 7 is inserted into the slit 21 to the inside of the guide slot 23 to the introduction port 28. In this case, the engagement between the protruding piece 7 and the connecting piece 17 is released, and the header 1 can be detached from the socket 2.

  According to the connector described above, both the mechanical coupling and the electrical connection between the header 1 and the socket 2 can be performed by the protruding piece 7 of the header contact 3 and the connection piece 17 of the socket contact 5. . Here, the spring pieces 20 on both sides of the slit 21 in the connecting piece 17 are elastically contacted with the neck portion 8 to ensure contact pressure, and the elasticity of the spring piece 20 is set to the length dimension of the spring piece 20 along the surface of the circuit board. Therefore, a desired contact pressure can be ensured regardless of the height dimensions of the header 1 and the socket 2. Therefore, the height of the header 1 and the socket 2 can be reduced.

(Embodiment 1)
The bump structure 30 of the present embodiment is used as the header contact 3 (see FIG. 2) in the above-described connector, and the header body 4 (see FIG. 2) in the above-described connector as shown in FIG. It is supported by the board | substrate 40 which comprises.

  The bump structure 30 is formed in a columnar shape from a conductive material, and has a columnar protruding piece 31 that protrudes in a direction orthogonal to the one surface on the one surface (upper surface in FIG. 1) side of the substrate 40. And a support piece 32 penetrating the substrate 40 in the thickness direction. The protruding piece 31 is a portion that becomes the protruding piece 7 of the header contact 3 described above, and is a head 34 (the head of the protruding piece 7) on the distal side of the base 33 (corresponding to the neck 8 of the protruding piece 7). It is formed in a so-called mushroom shape in which the portion 9) is thicker. In the present embodiment, the support piece 32 is formed in a cylindrical shape. Here, the support piece 32 is filled in a through hole 41 that penetrates the substrate 40 in the thickness direction and has an inner peripheral surface formed with a through hole plating 35 as a base layer. The through-hole plating 35 is formed in a cylindrical shape from a conductive material, and flange portions 36 projecting on both sides in the thickness direction of the substrate 40 extend around the through-hole 41 along the surface of the substrate 40. . In the present embodiment, an example is shown in which the head 34 of the protruding piece 31 is formed in a tapered shape with a diameter decreasing toward the distal end side.

  Here, the protruding piece 31 and the support piece 32 are arranged on a straight line along the thickness direction of the substrate 40. In the present embodiment, the central axis of the protruding piece 31 and the central axis of the support piece 32 are arranged on the same straight line. Furthermore, the protruding piece 31 and the support piece 32 are formed integrally from the same conductive material. In this embodiment, copper is adopted as the material of the protruding piece 31 and the support piece 32. Copper is also used as the material for the through-hole plating 35.

  According to the configuration described above, the bump structure 30 is supported by being embedded in the substrate 40 so that the support piece 32 that is a part of the bump structure 30 penetrates the substrate 40. Compared to the conventional bump structure 30 formed on the conductive pattern, there is an advantage that the bonding strength with the substrate 40 is improved. Thereby, for example, when the bump structure 30 is used as the header contact 3 of the connector described above, the bonding strength of the header contact 3 to the header body 4 is improved. Further, since the support piece 32 is filled in the through-hole 41 having the through-hole plating 35 formed on the inner peripheral surface, the support piece 32 is bonded to the through-hole plating 35 made of a conductive material. The bonding strength with the substrate 40 is improved as compared with the case of directly bonding to the substrate 40 made of. Further, the through-hole plating 35 has flange portions 36 protruding on both sides in the thickness direction of the substrate 40, and the substrate 40 is sandwiched between both flange portions 36, so that the through-hole plating 35 and the bumps are arranged in the thickness direction of the substrate 40. The structure 30 does not move.

  By the way, when the bump structure 30 is used as the header contact 3, a conductor pattern (not shown) and a terminal portion for external connection (not shown) are provided on the back surface (the lower surface in FIG. 1) of the substrate 40 that becomes the header body 4. ) Is formed. The protruding piece 31 is electrically connected to the conductor pattern on the back side of the substrate 40 using the through-hole plating 35 penetrating the substrate 40 and the support piece 32 as electric paths. That is, the support piece 32 not only improves the bonding strength of the bump structure 30 to the substrate 40, but also functions as an electric circuit between both surfaces in the thickness direction of the substrate 40 together with the through-hole plating 35. It is possible to realize an electric circuit having a smaller electric resistance than the case.

  Next, a method for manufacturing the bump structure 30 of this embodiment will be described with reference to FIG.

  As shown in FIG. 3A, a through hole 41 penetrating in the thickness direction is formed in the substrate 40, and plating (for example, electroless copper plating) is performed on the through hole 41, whereby the inner periphery of the through hole 41 is formed. Through-hole plating 35 serving as a base layer is formed on the surface (through-hole forming step). Thereafter, a first resist 52 is formed on the front surface of the substrate 40, and a third resist 51 is formed on the back surface of the substrate 40 (resist forming step). In the resist formation step, a neck forming hole opened in a circular shape that exposes the through-hole plating 35 on the first resist 52 formed on the surface of the substrate 40 on the side on which the protruding piece 31 is formed, using photolithography technology. 53 is formed. Specifically, a positive photosensitive resist that can be patterned into a desired shape by exposure and development is used as the first resist 52. Then, a mask (not shown) having an opening is stacked on the first resist 52 and irradiated with light (exposure), and only the portion of the first resist 52 irradiated with light from the opening of the mask is exposed. Is removed by subsequent development to form a neck molding hole 53. Here, a resist having a thickness larger than that of the third resist 51 is used as the first resist 52.

  After the resist formation step, a metal material (copper in this case) is deposited on the surface of the through-hole plating 35 by performing copper electrolytic plating in a state where the through-hole plating 35 is energized (support piece forming step). In the support piece forming step, the support piece 32 is formed by growing plating and filling the through hole 41 with a metal material. Then, by continuing the conductive deplating, the plating is also grown outside the through hole 41 (projection piece forming step). In the protruding piece forming step, as shown in FIG. 3B, the neck portion 33 of the protruding piece 31 is formed by filling the neck molding hole 53 in the first resist 52 with a metal material, and copper electrolytic plating is continued. The head 34 of the protruding piece 31 is formed outside the neck molding hole 53. That is, by performing copper electrolytic plating until the metal material overflows from the opening surface of the neck molding hole 53, the portion filled in the neck molding hole 53 of the metal material becomes the neck 33, and the portion overflowing from the neck molding hole 53 Becomes the head 34. Energization of the through-hole plating 35 at the time of copper electrolytic plating is performed through a conductor pattern (not shown) formed on the back surface of the substrate 40. Then, in the subsequent resist stripping step, the resists 51 and 52 are removed.

  That is, according to the manufacturing method, the height dimension of the neck portion 33 orthogonal to the surface of the substrate 40 can be set by the thickness dimension of the first resist 52, and the diameter of the neck portion 33 can be determined by the diameter of the neck molding hole 53. Can be set.

  By the way, in this embodiment, although the bump structure 30 used as the header contact 3 in the connector mentioned above was illustrated, it is not restricted to this example, For example, it is used as the guide protrusion 12 (refer FIG. 2) in the connector mentioned above. The present invention can also be applied to the bump structure 30. When the bump structure 30 is used for the guide protrusion 12, the neck portion 33 of the protruding piece 31 described above constitutes the small diameter portion 13 and the head portion 34 constitutes the large diameter portion 14. In addition, the bump structure 30 is not limited to a cylindrical shape, and may have various shapes such as a quadrangular prism shape and a polygonal column shape.

(Embodiment 2)
As shown in FIG. 4, the bump structure 30 of the present embodiment is different from the bump structure 30 of the first embodiment in that the protruding pieces 31 are formed on both sides in the thickness direction of the substrate 40, respectively. . Here, both protruding pieces 31 formed in the thickness direction of the substrate 40 have a common shape.

  According to this configuration, for example, when the bump structure 30 is used as the header contact 3 in the connector described above, the socket 2 can be connected to both sides of the header body 4 (substrate 40) in the thickness direction.

  In manufacturing the bump structure 30 of the present embodiment, in the resist formation step, the first resist is also applied to the third resist 51 formed on the back surface of the substrate 40 as shown in FIG. As in the case of 52, the neck molding hole 54 having a circular shape that exposes the through-hole plating 35 is formed by using a photolithography technique. Further, here, the third resist 51 and the first resist 52 having the same thickness are used. In the subsequent protruding piece forming step, a metal material is deposited on the surface of the through-hole plating 35 from the neck molding holes 53 and 54 in both the first and second resists 51 and 52 as shown in FIG. The protruding pieces 31 are formed on both sides of the substrate 40 in the thickness direction.

  Other configurations and functions are the same as those of the first embodiment.

(Embodiment 3)
In the present embodiment, a method for manufacturing the bump structure 30 in which the shape of the head 34 of the protruding piece 31 is stable will be described.

  In this manufacturing method, in the resist forming step, the second resist 56 having a head molding hole 55 larger than the neck molding hole 53 is accommodated in the head molding hole 55 as shown in FIG. Thus, the first resist 52 is laminated. In the protruding piece forming step, copper electrolytic plating is performed so that the metal material does not overflow from the opening surface of the head molding hole 55. The second resist 56 is stripped together with the first and third resists 51 and 52 in the resist stripping step.

  According to this manufacturing method, in the protruding piece forming step, the portion of the metal material overflowing from the opening surface of the neck molding hole 53 is accommodated in the head molding hole 55. Thus, the spread of the head 34 along the surface of the substrate 40 can be restricted. Therefore, the head 34 can be formed in a desired shape according to the design of the opening shape of the head molding hole 55, and the shape of the head 34 is stabilized. In short, the shape of the outer peripheral edge of the head 34 in the plane along the surface of the substrate 40 can be defined by the opening shape of the head molding hole 55, and the outer peripheral edge of the head 34 is the head molding hole 55. Even if the inner surface is reached, the outer peripheral edge of the head 34 can have a desired thickness by continuing the copper electrolytic plating.

  Moreover, according to the manufacturing method of this embodiment, instead of the bump structure 30 used for the connector described above, for example, the cross-sectional shape of the neck 33 of the protruding piece 31 is a perfect circle, and the cross-sectional shape of the head 34 is an ellipse. Thus, the bump structure 30 that can be mechanically coupled and electrically connected to a metal plate (not shown) provided with an elliptical through hole having the same shape as the head 34 can be configured. it can. That is, if the protruding piece 31 of the bump structure 30 is inserted into the through hole of the metal plate and the metal plate is rotated by 90 degrees in a plane along the surface of the substrate 40, the head 34 of the bump structure 30 is made of metal. The bump structure 30 and the metal plate are mechanically coupled and electrically connected to each other around the perforation hole in the plate. The manufacturing method of the present embodiment is particularly useful when the cross-sectional shape different from the neck portion 33 is adopted for the head portion 34 as described above.

  Other configurations and functions are the same as those of the first embodiment.

It is a schematic sectional drawing which shows the structure of Embodiment 1 of this invention. The connector using a bump structure same as the above is shown, (a) is a perspective view of a non-bonding state, and (b) is a perspective view of a connection state. It is a schematic sectional drawing which shows the manufacturing method of a bump structure same as the above. It is a schematic sectional drawing which shows the structure of Embodiment 2 of this invention. It is a schematic sectional drawing which shows the manufacturing method of a bump structure same as the above. It is a schematic sectional drawing which shows the manufacturing method of the bump structure in Embodiment 3 of this invention. It is a schematic sectional drawing which shows the example of the manufacturing method of the conventional bump structure.

Explanation of symbols

30 Bump structure 31 Projection piece 32 Support piece 33 Neck 34 Head 35 Through-hole plating (underlayer)
40 Substrate 41 Through-hole 52 First resist 53 Neck forming hole 55 Head forming hole 56 Second resist

Claims (4)

A columnar bump structure made of a conductive material, comprising a support piece supported by the substrate by penetrating the substrate in the thickness direction, and a protruding piece protruding from the support piece on at least one surface side of the substrate,
The projecting piece is formed in different thicknesses on the proximal side and the distal side so that the head on the distal side is thicker than the neck on the proximal side ,
The support piece is provided in a through hole in which through hole plating is formed on the inner peripheral surface, and is combined with the through hole plating.
The through-hole plating has a flange portion protruding on both sides in the thickness direction of the substrate, and the bump structure characterized in that the substrate is sandwiched between both flange portions .   The bump structure according to claim 1, wherein the protruding pieces are formed on both sides of the substrate in the thickness direction.   3. The method for manufacturing a bump structure according to claim 1 or 2, wherein a base layer made of the conductive material is formed on an inner peripheral surface of the through hole having a through hole penetrating in a thickness direction. Using the substrate, a resist forming step of forming a first resist having a neck molding hole that exposes a through hole on the surface of the substrate on the side where the protruding piece is to be formed, and plating is performed after the resist forming step. A support piece forming step of forming the support piece by filling the through hole with the conductive material, and plating is performed after the support piece forming step, and the neck portion is formed by filling the neck portion molding hole with the conductive material. In addition, it has a protruding piece forming step for forming the head outside the neck molding hole by continuing plating, and a resist peeling step for removing the resist after the protruding piece forming step. Method for manufacturing a bump structure characterized.   In the resist forming step, the second resist having a head molding hole larger than the neck molding hole is laminated on the first resist so that the neck molding hole is accommodated in the head molding hole. A method for manufacturing a bump structure according to claim 3.

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