JP2014130969A - Wiring board and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve connection reliability by improving bonding strength at a connection interface between a via and wiring.SOLUTION: A wiring board 1 comprises: a resin substrate 10; front wiring 11 formed to be buried on one surface (surface 10a) side of the resin substrate 10; a conductive via 12 which penetrates the resin substrate 10 and is formed integrally with the front wiring 11; rear wiring 13 which is formed on the other surface (rear surface 10b) side of the resin substrate 10 and is connected to the conductive via 12; and a metal connection layer 14 forming an interface between the conductive via 12 and the rear wiring 13.

Description

  The present invention relates to a wiring board on which electronic components are surface-mounted and a manufacturing method thereof.

  Conventionally, for example, a wiring board disclosed in Patent Document 1 is known as a type of wiring board on which electronic components are surface-mounted. In this wiring board, a pattern is transferred to one or both surfaces of a resin base material by a mold to form a wiring groove, a through hole reaching the wiring groove is formed in the resin base material, and a conductive material is formed in the wiring groove. And wirings and vias formed by filling the through holes.

JP 2001-244609 A

  However, in the prior art wiring board disclosed in Patent Document 1, for example, when a wiring is formed on the surface of the resin base and connected to a via exposed from the resin base, the connection interface between the via and the wiring Since the surface becomes flush with the surface of the resin base material, there is a problem that both are easy to peel off when a force causing cracks in the surface direction is applied.

  An object of the present invention is to provide a wiring board capable of solving the above-described problems caused by the prior art, improving the coupling force at the connection interface between the via and the wiring, and improving the connection reliability, and the manufacturing method thereof. And

  A wiring board according to the present invention includes a resin base material, a surface wiring pattern embedded and formed on one surface side of the resin base material, and a conductive via penetrating the resin base material and integrally formed with the surface wiring pattern. And a back surface wiring pattern formed on the other surface side of the resin base material and connected to the conductive via, and a metal connection layer that forms an interface between the conductive via and the back surface wiring pattern. To do.

  According to the wiring board according to the present invention, since the metal connection layer forming the interface between the conductive via and the back surface wiring pattern is provided, a chemical bonding force is added to the connection interface between the conductive via and the back surface wiring, Connection reliability can be improved.

  In one embodiment of the present invention, the metal connection layer is made of an intermetallic compound.

  In another embodiment of the present invention, the metal connection layer is made of solder.

  In still another embodiment of the present invention, the metal connection layer has a concave or convex cross-sectional shape with respect to the other surface of the resin base material.

  In the method for manufacturing a wiring board according to the present invention, a circuit pattern including a through hole is formed by imprinting on one surface side of a resin base material, and the circuit pattern is filled with a conductive paste, and the resin base material is filled with the circuit pattern. Forming a surface wiring pattern embedded on the one surface side including the conductive via corresponding to the through hole; forming a metal connection layer on the conductive via on the other surface side of the resin base; and A backside wiring pattern is formed on the other surface side of the material to be connected in a state where the conductive via and the metal connection layer form an interface.

  According to the method for manufacturing a wiring board according to the present invention, it is possible to manufacture a wiring board having the same effects as the above-described wiring board.

  According to the present invention, the coupling force at the connection interface between the via and the wiring can be improved, and the connection reliability can be improved.

It is sectional drawing which shows the structure of the wiring board which concerns on the 1st Embodiment of this invention. It is a flowchart which shows the manufacturing process of the wiring board. It is sectional drawing which shows the same wiring board in order of a manufacturing process. It is sectional drawing which shows the structure of the wiring board which concerns on the 2nd Embodiment of this invention. It is sectional drawing which shows the same wiring board in order of a manufacturing process. It is sectional drawing which shows the structure of the wiring board which concerns on the 3rd Embodiment of this invention. It is sectional drawing which shows the same wiring board in order of a manufacturing process. It is sectional drawing which shows the structure of the wiring board which concerns on the 4th Embodiment of this invention. It is sectional drawing which shows the same wiring board in order of a manufacturing process. It is sectional drawing which shows the structure of the wiring board which concerns on the 5th Embodiment of this invention. It is sectional drawing which shows the same wiring board in order of a manufacturing process. It is sectional drawing which shows the structure of the wiring board which concerns on the 6th Embodiment of this invention. It is sectional drawing which shows the same wiring board in order of a manufacturing process. It is sectional drawing which shows the structure of the wiring board which concerns on other embodiment of this invention. It is a flowchart which shows the manufacturing process of the same wiring board. It is sectional drawing which shows the same wiring board in order of a manufacturing process.

  Hereinafter, a wiring board and a manufacturing method thereof according to embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[First Embodiment]
FIG. 1 is a cross-sectional view showing the structure of a wiring board according to the first embodiment of the present invention. The wiring substrate 1 according to the first embodiment includes a resin base material 10 and a surface wiring 11 embedded and formed on one surface (surface 10a) side of the resin base material 10. Further, the wiring substrate 1 is formed on the other surface (back surface 10b) side of the resin base material 10 and is connected to the conductive via 12 through the resin base material 10 and integrally formed with the surface wiring 11. The backside wiring 13 is provided. Further, the wiring substrate 1 includes a metal connection layer 14 that forms an interface between the conductive via 12 and the back surface wiring 13.

  The resin substrate 10 is made of, for example, a resin film having a thickness of about 25 μm. As the resin film, it is possible to use a resin film made of thermoplastic or thermosetting polyimide, semi-cured polyimide, polyethylene terephthalate (PET), semi-cured epoxy, polyolefin, other olefin resin, liquid crystal polymer, or the like. it can.

  The surface wiring 11 and the conductive via 12 are made of a conductive material filled in an imprint-type uneven circuit pattern including the through hole 9 formed in the resin base material 10. As the conductive material, for example, a metal such as copper, gold, silver, or platinum, carbon, or the like is used.

  When a conductive paste is used as the conductive material, the conductive paste includes, for example, at least one kind of low electrical resistance metal particles selected from nickel, gold, silver, zinc, aluminum, iron, tungsten, etc., bismuth, And at least one kind of low melting point metal particles selected from indium, lead and the like.

  The conductive paste is made of a paste in which tin is contained as a component in these metal particles and a binder component mainly composed of epoxy, acrylic, urethane, or the like is mixed. The conductive paste thus configured can form an alloy by melting the contained tin and the low melting point metal at 200 ° C. or less, and particularly can form an intermetallic compound with copper, silver, or the like. With possible characteristics.

  The conductive paste can also be constituted by a nanopaste in which fillers such as gold, silver, copper, nickel, etc. having a nanometer particle diameter are mixed with the binder component as described above. In addition, the conductive paste can also be configured by a paste in which metal particles such as nickel are mixed with the binder component as described above. In this case, the conductive paste has a characteristic that electrical connection is made when the metal particles come into contact with each other.

  For the surface wiring 11 and the conductive via 12 of the wiring substrate 1 according to the first embodiment, for example, a seed layer (not shown) is formed by electroless plating on the uneven transfer pattern transferred to the resin base material 10. Further, the conductive material is filled by electrolytic plating. The seed layer may be formed by sputtering or the like, and the surface wiring 11 and the conductive via 12 may be filled by screen printing or the like.

  The back surface wiring 13 is formed by patterning using the conductive material by a full additive method, a semi-additive method, screen printing, ink jet, or the like. The metal connection layer 14 forms a bonding layer corresponding to the interface between the conductive via 12 and the back surface wiring 13. The metal connection layer 14 is formed in order to ensure the bonding between the conductive material filled in the transfer pattern of the resin base material 10 and the conductive material of the patterned back surface wiring 13.

  As the material of the metal connection layer 14, an intermetallic compound, solder, or the like is used, and any material can be used as long as it has adhesion to the conductive material and can be electrically joined. Specific examples of the material include an insert material, a brazing material, and solder. Insert materials and brazing materials include copper (Cu), silver (Ag), nickel (Ni), titanium (Ti), zirconium (Zr), hafnium (Hf), chromium (Cr), niobium (Nb), vanadium ( Cu), Ag, Ni-based alloys and the like including V).

  As the solder, a multi-component solder containing tin (Sn), gold (Au), lead (Pb), zinc (Zn), indium (In), bismuth (Bi), Cu, and the like is typically given. Bonding by the metal connection layer 14 is performed by bonding by intermolecular force due to wetting and spreading, bonding by solid phase diffusion and liquid phase diffusion, chemical bonding by generation of an intermetallic compound, or the like. The metal connection layer 14 is formed by plating, screen printing, ink jet, or the like.

  In addition, since the conductive via 12 is filled and formed with the through hole 9 formed in the resin base material 10 opened, the conductive via 12 can be adjusted from the surface of the resin base material 10 on the back surface wiring 13 side by appropriately adjusting the filling conditions. The flange-shaped end portion 12a having a diameter larger than the diameter of the through hole 9 is protruded. Since the end 12a protrudes like a bowl, a so-called anchor effect can be achieved.

  According to the wiring board 1 configured as described above, the metal connection layer 14 that forms the interface between the conductive via 12 and the back surface wiring 13 is provided. A strong coupling force is added. In addition, since the joint portion between the conductive via 12 and the back surface wiring 13 is not flush with the surface of the resin base material 10, even if a force that causes a crack in the surface direction of the resin base material 10 is applied, A structure in which the back surface wiring 13 is difficult to peel off is realized.

  Further, since the surface wiring 11 and the conductive via 12 are integrally formed, and the surface wiring 11 is embedded in the resin base material 10, the separation between the surface wiring 11 and the conductive via 12 hardly occurs structurally. The height can be reduced. Thereby, according to the wiring board 1 which concerns on 1st Embodiment, connection reliability can be improved.

Next, a method for manufacturing a wiring board according to the first embodiment will be described.
FIG. 2 is a flowchart showing the manufacturing process of the wiring board. FIG. 3 is a cross-sectional view showing the wiring board in the order of the manufacturing process.
First, as shown to Fig.3 (a), the imprint type | mold 20 in which the uneven | corrugated circuit-shaped pattern 21 was formed, for example, and the resin base material 10 which consists of a thermoplastic polyimide resin film are prepared (step S100).

  The imprint mold 20 is, for example, a silicon having a pattern 21 having a minimum line / space (L / S) of 5 μm / 5 μm, a wiring height of 5 μm, and a pillar having a diameter of 20 μm and a diameter of φ10 μm formed on a land of diameter of 30 μm. It consists of a mold. The pitch and material of the pattern 21 are selected as necessary. The imprint mold 20 may be formed of nickel, copper, diamond-like carbon (DLC), or the like in addition to the above silicon, or may be subjected to easy release treatment by coating the surface with a fluorine resin or the like. .

  Next, as shown in FIG. 3 (b), the pattern 21 of the imprint mold 20 is opposed to the resin base material 10, pressed against the resin base material 10 while being heated to a predetermined temperature, and configured by the pattern 21. The transferred pattern 15 is transferred to the resin base material 10 (step S102). At this time, the resin base material 10 and the imprint mold 20 are preferably heated to a temperature at which the resin material constituting the resin base material 10 becomes soft (for example, about 280 ° C.), and then a predetermined pressure (for example, 5 MPa). To transfer the transfer pattern 15. In addition, when the resin base material 10 consists of a thermoplastic resin as mentioned above, it is desirable for the predetermined temperature to be a temperature equal to or higher than the glass transition point.

  Then, as shown in FIG. 3C, the resin material is cooled below the softening temperature, the imprint mold 20 is released from the resin base material 10, and the concave circuit pattern 16 is formed on the resin base material 10. Form (step S104). When the circuit pattern 16 is formed, as shown in FIG. 3D, a seed layer (not shown) is formed by electroless plating in the circuit pattern 16 from the surface 10a side of the resin base material 10, for example, according to predetermined filling conditions. Then, the conductive material 17 is filled by electrolytic plating (step S106). The conductive material 17 may be filled in the circuit pattern 16 by other ink jet or screen printing.

  At this time, since the through hole 9 of the circuit pattern 16 is in an open state on the back surface 10b side of the resin base material 10, a part of the filled conductive material 17 protrudes in a bowl shape from the back surface 10b due to filling conditions. Become. The protruding conductive material 17 has a diameter larger than the hole diameter of the through hole 9. Thereafter, as shown in FIG. 3E, excess conductive material 17 on the surface 10a side of the resin base material 10 is removed by polishing, etching, or the like (step S108). As a result, the front surface wiring 11 is formed in a flat (flat) state with the front surface 10a of the resin base material 10, and the conductive vias 12 integrated with the front surface wiring 11 are in a state where the end portion 12a protrudes from the back surface 10b. Form (step S110).

  In addition, the process of the said step S108 is abbreviate | omitted by optimizing the filling conditions of the electrically conductive material 17 in the said step S106, so that the excess electrically conductive material 17 may not be formed on the surface 10a of the resin base material 10. FIG. Is possible. Thereafter, as shown in FIG. 3 (f), a metal connection made of the above-described material is formed on the flange-shaped end portion 12a of the conductive via 12 protruding on the back surface 10b side of the resin base material 10 by plating, screen printing, inkjet, or the like. Layer 14 is formed (step S112).

  When the metal connection layer 14 is formed, as shown in FIG. 3G, the back surface wiring 13 is patterned and formed on the back surface 10b of the resin base material 10 by the full additive method, the semi-additive method, or the like (step S114). . Finally, although not shown in the figure, in order to securely bond the conductive via 12 (end portion 12a) and the backside wiring 13 through the metal connection layer 14, heat treatment or heat pressure treatment is performed (step S116). The wiring board 1 according to the first embodiment is manufactured.

In the processing in step S116, for example, when the metal connection layer 14 is made of Sn-Bi solder and the conductive via 12 and the backside wiring 13 are made of Cu, the solder is melted at a heating temperature of about 150 ° C. Therefore, the metal connection layer 14 made of the intermetallic compound of _Cu 3 Sn and _Cu 6 Sn ₅ is generated between the conductive via 12 and the backside interconnect 13, the bonding strength of the conductive vias 12 and the back surface wiring 13 is improved.

  As described above, in the wiring board 1 according to the first embodiment, the connection interface between the conductive via 12 and the back surface wiring 13 is not flat with the back surface 10b of the resin base material 10, and the connection interface is formed by the metal connection layer 14. Since it is configured and a chemical bonding force is further applied, the conductive via 12 and the back surface wiring 13 are difficult to peel off, and the connection reliability can be improved.

[Second Embodiment]
FIG. 4 is a cross-sectional view showing the structure of a wiring board according to the second embodiment of the present invention. FIG. 5 is a cross-sectional view showing the wiring board in the order of the manufacturing process. As shown in FIG. 4, the wiring substrate 2 according to the second embodiment has the same basic configuration as the wiring substrate 1 according to the first embodiment, but is electrically conductive on the back surface 10 b side of the resin base material 10. The difference is that the shape of the end 12b of the via 12 is different.

  The wiring board 2 is manufactured as follows. That is, as in the manufacturing process described above, as shown in FIG. 5A, an imprint mold 20 and a resin base material 10 are prepared, and as shown in FIG. 5B, a pattern 21 of the imprint mold 20 is prepared. 5 is transferred to the resin substrate 10, and the imprint mold 20 is released to form the circuit pattern 16 as shown in FIG. 5C.

  And as shown in FIG.5 (d), the filling conditions are changed in the circuit pattern 16, and it fills with the electrically-conductive material 17, and as shown in FIG.5 (e), the surplus by the surface 10a side of the resin base material 10 is shown. The conductive material 17 is removed. As a result, the end 12b of the conductive via 12 continuing from the formed surface wiring 11 is in a state of projecting in a curved shape from the back surface 10b side of the resin base material 10 with the same diameter as or smaller than the diameter of the through hole 9. .

  Thereafter, as shown in FIG. 5 (f), a metal connection layer 14 is formed on the curved end portion 12b of the protruding conductive via 12, and as shown in FIG. 5 (g), the back surface of the resin base material 10 is formed. The back surface wiring 13 is formed on 10b, heat processing etc. are performed, and the wiring board 2 which concerns on 2nd Embodiment is manufactured. Including the portion of the metal connection layer 14 to be formed, the end 12 b of the conductive via 12 may have a diameter larger than the hole diameter of the through hole 9.

  Even with the wiring substrate 2 according to the second embodiment having such a configuration, the connection interface between the conductive via 12 and the back surface wiring 13 does not become flat with the back surface 10 b of the resin base material 10. And since the metal connection layer 14 is formed, there can exist an effect similar to the wiring board 1 which concerns on 1st Embodiment.

[Third Embodiment]
FIG. 6 is a cross-sectional view showing the structure of a wiring board according to the third embodiment of the present invention. FIG. 7 is a cross-sectional view showing a wiring board in the order of manufacturing steps. As shown in FIG. 6, the basic configuration of the wiring board 3 according to the third embodiment is the same as that of the wiring boards 1 and 2 according to the first and second embodiments. The difference is that the shape of the end 12c of the conductive via 12 on the back surface 10b side is different.

  The wiring board 3 is manufactured as follows. That is, similarly to the above-described manufacturing process, an imprint mold 20 and a resin base material 10 are prepared as shown in FIG. 7A, and a pattern 21 of the imprint mold 20 is prepared as shown in FIG. 7 is transferred to the resin base material 10, and the imprint mold 20 is released to form a circuit pattern 16 as shown in FIG. 7C.

  Then, as shown in FIG. 7 (d), the filling conditions are changed in the circuit pattern 16 to fill the conductive material 17, and as shown in FIG. 7 (e), surplus on the surface 10a side of the resin base material 10 is filled. The conductive material 17 is removed. Thereby, the end 12b of the conductive via 12 continuing from the formed surface wiring 11 has a diameter smaller than the hole diameter of the through hole 9 and a part thereof protrudes in a sharp curved shape from the back surface 10b side of the resin base material 10 It becomes.

  Specifically, when the back surface 10b of the resin base material 10 is used as the reference surface, the end portion 12c protrudes outward from the reference surface, and the skirt end portion of the skirt portion continuing from the protruding top portion is from the reference surface. Is also formed in a shape retracted inward (that is, on the surface 10a side). Thereafter, as shown in FIG. 7 (f), the metal connection layer 14 is formed on the projecting top and the bottom of the end 12 c of the conductive via 12. Since the metal connection layer 14 is formed in a state along the end 12c, the metal connection layer 14 is formed with a portion that protrudes or retracts from the reference surface.

  Then, as illustrated in FIG. 7G, the back surface wiring 13 is formed on the back surface 10 b of the resin base material 10, and heat treatment or the like is performed to manufacture the wiring substrate 3 according to the third embodiment. Even with the wiring substrate 3 according to the third embodiment having such a configuration, the connection interface between the conductive via 12 and the back surface wiring 13 does not become flat with the back surface 10 b of the resin base material 10. And since the metal connection layer 14 is formed, there can exist an effect similar to the wiring boards 1 and 2 which concern on 1st and 2nd embodiment.

[Fourth Embodiment]
FIG. 8 is a cross-sectional view showing the structure of a wiring board according to the fourth embodiment of the present invention. FIG. 9 is a cross-sectional view showing the wiring board in the order of the manufacturing process. As shown in FIG. 8, the basic configuration of the wiring board 4 according to the fourth embodiment is the same as that of the wiring boards 1 to 3 according to the first to third embodiments. The difference is that the end 12d of the conductive via 12 on the back surface 10b side does not protrude outward from the back surface 10b.

  The wiring board 4 is manufactured as follows. That is, as in the manufacturing process described above, as shown in FIG. 9A, an imprint mold 20 and a resin base material 10 are prepared, and as shown in FIG. 9B, a pattern 21 of the imprint mold 20 is prepared. 9 is transferred to the resin substrate 10, and the imprint mold 20 is released to form the circuit pattern 16 as shown in FIG. 9C.

  Then, as shown in FIG. 9D, the conductive material 17 is changed so that the conductive material 17 stops in the through hole 9 by changing the filling condition in the circuit pattern 16, that is, the conductive material 17 does not protrude from the back surface 10b. 17 and the excess conductive material 17 on the surface 10a side of the resin base material 10 is removed as shown in FIG.

  Thereby, the end 12d of the conductive via 12 continuing from the formed front surface wiring 11 is a convex type that does not protrude from the back surface 10b side of the resin base material 10 with a diameter equal to or smaller than the diameter of the through hole 9. A curved surface is formed inside the through hole 9. Thereafter, as shown in FIG. 9 (f), a metal connection layer 14 is formed on the end 12d of the conductive via 12 in the through hole 9, and as shown in FIG. 9 (g), the back surface of the resin base material 10 is formed. The back surface wiring 13 is formed on 10b, heat processing etc. are performed, and the wiring board 4 which concerns on 4th Embodiment is manufactured.

  A part of the back surface wiring 13 enters the inside of the through hole 9 from the back surface 10 b and is joined to the conductive via 12 through the metal connection layer 14. Also with the wiring substrate 4 according to the fourth embodiment having such a configuration, the connection interface between the conductive via 12 and the back surface wiring 13 is not flat with the back surface 10b of the resin base material 10, and the metal connection layer 14 is formed. Therefore, the same effects as the wiring boards 1 to 3 according to the first to third embodiments can be obtained.

[Fifth Embodiment]
FIG. 10 is a cross-sectional view showing the structure of a wiring board according to the fifth embodiment of the present invention. FIG. 11 is a cross-sectional view showing a wiring board in the order of manufacturing steps. As shown in FIG. 10, the wiring board 5 according to the fifth embodiment has the same basic configuration as the wiring board 4 according to the fourth embodiment, but is electrically conductive on the back surface 10 b side of the resin base material 10. The difference is that the shape of the end 12e of the via 12 is different.

  The wiring board 5 is manufactured as follows. That is, similarly to the above-described manufacturing process, an imprint mold 20 and a resin base material 10 are prepared as shown in FIG. 11A, and a pattern 21 of the imprint mold 20 is prepared as shown in FIG. As shown in FIG. 11C, the imprint mold 20 is released to form the circuit pattern 16.

  And as shown in FIG.11 (d), the filling conditions are changed in the circuit pattern 16, and it fills with the electrically conductive material 17, and as shown in FIG.11 (e), the surplus by the surface 10a side of the resin base material 10 is shown. In addition to removing the conductive material 17, a predetermined amount of the conductive material 17 on the back surface 10 b side is removed so as to be recessed in the through hole 9 by etching or sandblast island. Thereby, the end 12e of the conductive via 12 continuing from the formed surface wiring 11 has the same diameter as the through hole 9 and has a concave curved shape that does not protrude from the back surface 10b side of the resin substrate 10. It will be in the state formed inside.

  Thereafter, as shown in FIG. 11 (f), a metal connection layer 14 is formed on the end portion 12 e of the conductive via 12 in the through hole 9, and as shown in FIG. 11 (g), the back surface of the resin base material 10. The back surface wiring 13 is formed on 10b, heat processing etc. are performed, and the wiring board 5 which concerns on 5th Embodiment is manufactured.

  Also in this case, the back surface wiring 13 partially enters the through hole 9 from the back surface 10b and is joined to the conductive via 12 via the metal connection layer 14, so that the wiring substrate 5 according to the fifth embodiment However, the connection interface between the conductive via 12 and the back surface wiring 13 is not flat with the back surface 10b of the resin base material 10, and the metal connection layer 14 is formed, and the same operation as that of the wiring substrate 4 according to the fourth embodiment. There is an effect.

[Sixth Embodiment]
FIG. 12 is a cross-sectional view showing the structure of the wiring board according to the sixth embodiment of the present invention. FIG. 13 is a cross-sectional view showing a wiring board in the order of manufacturing steps. As shown in FIG. 12, the wiring board 6 according to the sixth embodiment has the same basic configuration as the wiring board 5 according to the fifth embodiment, but the conductive property on the back surface 10 b side of the resin base material 10. The difference is that the shape of the end portion 12f of the via 12 is different.

  The wiring board 6 is manufactured as follows. That is, as in the manufacturing process described above, as shown in FIG. 13A, an imprint mold 20 and a resin base material 10 are prepared, and as shown in FIG. 13B, a pattern 21 of the imprint mold 20 is prepared. As shown in FIG. 13C, the imprint mold 20 is released to form the circuit pattern 16.

  And as shown in FIG.13 (d), the filling conditions are changed in the circuit pattern 16, and it fills with the electrically conductive material 17, and as shown in FIG.13 (e), the surplus by the surface 10a side of the resin base material 10 is shown. In addition to removing the conductive material 17, a predetermined amount of the conductive material 17 on the back surface 10 b side is removed so as to be recessed flat in the through hole 9. As a result, the end 12f of the conductive via 12 continuing from the formed surface wiring 11 has the same diameter as the through hole 9 and does not protrude from the back surface 10b side of the resin base material 10 so that the inside of the through hole 9 It will be in the state formed.

  Thereafter, as shown in FIG. 13 (f), a metal connection layer 14 is formed on the end portion 12f of the conductive via 12 in the through hole 9, and as shown in FIG. 13 (g), the back surface of the resin base material 10 is formed. The back surface wiring 13 is formed on 10b, heat processing etc. are performed, and the wiring board 6 which concerns on 6th Embodiment is manufactured.

  Also in this case, the back surface wiring 13 partially enters the through hole 9 from the back surface 10b and is joined to the conductive via 12 via the metal connection layer 14, so that the wiring substrate 6 according to the sixth embodiment However, the connection interface between the conductive via 12 and the back surface wiring 13 is not flat with the back surface 10b of the resin base material 10, and the metal connection layer 14 is formed, and the same operation as that of the wiring substrate 5 according to the fifth embodiment is achieved. There is an effect.

[Other Embodiments]
In addition, the wiring board according to the present invention may have the following configuration.
FIG. 14 is a cross-sectional view showing the structure of a wiring board according to another embodiment of the present invention. FIG. 15 is a flowchart showing a manufacturing process of the wiring board. FIG. 16 is a cross-sectional view showing a wiring board in the order of manufacturing steps.

  The wiring board according to the present embodiment can be manufactured by similarly applying various materials and various processes in the above-described embodiments. This wiring board includes a resin base material, a surface wiring pattern embedded in one surface of the resin base material, a conductive via penetrating the resin base material and integrally formed with the surface wiring pattern, and a resin base material. A backside wiring pattern formed on the other surface side and connected to the conductive via, a metal connection layer that forms an interface between the conductive via and the backside wiring pattern, and a predetermined position on the front side wiring pattern and the backside wiring pattern, respectively. And a solder ball provided on the concave portion.

  Specifically, as shown in FIG. 14, the wiring substrate 7 includes a resin base material 10, a surface wiring 11 embedded and formed on the surface 10 a side of the resin base material 10, and a surface penetrating the resin base material 10. The conductive via 12 formed integrally with the wiring 11, the back surface wiring 13 formed on the back surface 10b side of the resin substrate 10 and connected to the conductive via 12, and the metal connection forming the interface between the conductive via 12 and the back surface wiring 13 Although the point provided with the layer 14 is the same as that of the wiring boards 1-6 which concern on the said embodiment, the following points differ.

  That is, the wiring board 7 includes a solder resist 8 formed on the front surface 10a and the back surface 10b of the resin base material 10 so as to expose predetermined portions of the front surface wiring 11 and the back surface wiring 13. In addition, the wiring board 7 includes recesses 11a and 13a formed on the front surface wiring 11 and the back surface wiring 13 at locations exposed by the solder resist 8, and further solder balls formed on the recesses 11a and 13a. 19 is provided.

  In the wiring board 7 configured in this manner, since the solder balls 19 are provided on the recessed portions 11a and 13a of the respective wirings 11 and 13, compared with the case where the solder balls are formed on the planar wiring, The contact area between the wirings 11 and 13 and the solder ball 19 can be increased. Further, the connection interface between each of the wirings 11 and 13 and the solder ball 19 is not a planar shape but a three-dimensional curved surface shape.

  Further, the mounting height of the solder balls 19 can be suppressed by the amount of the recesses of the recess portions 11a and 13a, and the lateral expansion of the solder balls 19 is also suppressed, so that the diameter of the solder balls 19 can be reduced. Therefore, the connection reliability between the wirings 11 and 13 and the solder balls 19 can be improved, and the overall height of the wiring board 7 can be reduced.

  The wiring board 7 according to this embodiment is manufactured as follows. That is, similarly to the manufacturing process described in the above-described embodiment, as shown in FIG. 16A, an imprint mold 20 and a resin base material 10 are prepared, and as shown in FIG. The transfer pattern 15 constituted by the pattern 21 of the mold 20 is transferred to the resin substrate 10, and the imprint mold 20 is released to form the circuit pattern 16 as shown in FIG.

  Then, as shown in FIG. 16 (d), the conductive material 17 is filled in the circuit pattern 16 according to the filling conditions, and as shown in FIG. 16 (e), the surplus conductive material on the surface 10a side of the resin base material 10 is filled. 17 is removed, and a predetermined amount of the conductive material 17 on the back surface 10 b side is removed so as to be recessed flat in the through hole 9.

  As a result, the end 12g of the conductive via 12 continuing from the formed surface wiring 11 has the same diameter as the through hole 9 and does not protrude from the back surface 10b side of the resin base material 10 so that the inside of the through hole 9 It will be in the state formed. Thereafter, a metal connection layer 14 is formed on the end portion 12g of the conductive via 12 in the through hole 9, and a back surface wiring 13 is formed on the back surface 10b of the resin substrate 10 as shown in FIG. And heat treatment.

  Then, as shown in FIGS. 15 and 16 (g), openings 8a and 8b are respectively formed on the front surface 10a and the back surface 10b of the resin base material 10 so that the predetermined portions of the front surface wiring 11 and the back surface wiring 13 are exposed. A solder resist 8 having a predetermined pattern is formed (step S118).

  When the solder resist 8 is formed, as shown in FIGS. 15 and 16 (h), the recesses 11a and 13a are selectively formed on the front surface wiring 11 and the back surface wiring 13 in the openings 8a and 8b by etching or sandblasting. Is formed (step S120). Finally, although not shown, solder is filled in the formed recesses 11a and 13a to form solder balls 19 (step S122), and the wiring board 7 according to this embodiment is manufactured. Accordingly, the same operational effects as those of the wiring substrates 1 to 6 according to the above-described embodiment can be obtained, and the overall height of the substrate when the solder balls 19 are formed can be reduced.

DESCRIPTION OF SYMBOLS 1-7 Wiring board 8 Solder resist 8a, 8b Opening 9 Through hole 10 Resin base material 11 Front surface wiring 11a, 13a Recessed part 12 Conductive via 13 Back surface wiring 14 Metal connection layer 15 Transfer pattern 16 Circuit pattern 17 Conductive material 19 Solder ball 20 Imprint type

Claims (5)

A resin substrate;
A surface wiring pattern embedded and formed on one surface side of the resin substrate;
Conductive vias penetrating the resin substrate and integrally formed with the surface wiring pattern;
A backside wiring pattern formed on the other surface side of the resin base material and connected to the conductive via;
A wiring board comprising: a metal connection layer that forms an interface between the conductive via and the backside wiring pattern.   The wiring board according to claim 1, wherein the metal connection layer is made of an intermetallic compound.   The wiring board according to claim 1, wherein the metal connection layer is made of solder.   The wiring board according to claim 1, wherein the metal connection layer has a concave or convex cross-sectional shape with respect to the other surface of the resin base material. Form a circuit pattern including through-holes on one side of the resin substrate by imprinting,
Filling the circuit pattern with a conductive paste to form a surface wiring pattern embedded on the one surface side including conductive vias corresponding to the through holes in the resin base material,
Forming a metal connection layer on the conductive via on the other side of the resin substrate;
A method of manufacturing a wiring board, comprising: forming a backside wiring pattern connected to the other surface side of the resin base material in a state where the conductive via and the metal connection layer form an interface.

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