JP2014130919A - Multi-layer printed wiring board and manufacturing method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively inhibit flow of a conductive paste during the lamination thereby improving the reliability of interlayer connection.SOLUTION: In a multi-layer printed wiring board 100, first and second printed wiring base materials 10, 20, in which first and second conductor circuit layers 11, 12 are respectively formed, are laminated through an adhesive layer 9. The first conductor circuit layer 11 of the first printed wiring base material 10 and the second conductor circuit layer 12 of the second printed wiring base material 20 are connected with each other through a via 14 which penetrates through a first insulation base material 19 and the adhesion layer 9 in a lamination direction. An insulation layer 15 functioning as an outflow prevention part that prevents a conductive member forming the via 14 from flowing out to the adhesive layer 9 is provided on a surface 10b of the first insulation base material 19. When heating press is performed on the first and second printed wiring base materials 10, 20, the insulation layer 15 prevents the conductive member forming the via 14 from flowing out and dispersing to the adhesive layer 9. Thus, the connection reliability of interlayer connection is improved.

Description

  The present invention relates to a multilayer printed wiring board in which conductor circuit layers are interlayer-connected and a manufacturing method thereof.

  In a multilayer printed wiring board in which conductor circuit layers are connected between layers, the layers are connected by, for example, IVH (Interstitial Via Hole).

  In the multilayer printed wiring board disclosed in Patent Document 1 below, a plurality of insulating base materials on which conductor circuits are formed are multilayered by bonding with an interlayer adhesive, and a conductive paste is filled in via holes formed in each insulating base material Thus, the interlayer conduction is obtained.

JP 2012-79768 A

  In the multilayer printed wiring board disclosed in Patent Document 1, a process of heating and press-bonding an adhesive provided between a plurality of insulating base materials when forming a laminate (hereinafter also referred to as a curing process). Is used). At that time, if the fluidity of the adhesive that connects the resin insulating bases is increased, the pressure applied to the conductive paste via formed in the IVH from the adhesive is weakened, and the conductive paste may spread. . When the conductive paste forming the via spreads, the connection reliability of the via is lowered.

  The present invention provides a multilayer printed wiring board and a method for manufacturing the same, which can solve the problems caused by the prior art described above, can effectively suppress the flow of the conductive paste during lamination, and can improve the reliability of interlayer connection. The purpose is to provide.

  In the multilayer printed wiring board according to the present invention, a plurality of printed wiring base materials in which a conductor circuit layer is formed on an insulating base material are stacked via an adhesive layer, and vias penetrating the insulating base material and the adhesive layer are provided in the stacking direction. A multilayer printed wiring board in which the conductor circuit layers are connected to each other via a conductive member outflow prevention portion on a contact surface between the insulating base and the adhesive layer.

  According to the multilayer printed wiring board according to the present invention, the conductor circuit layer is formed on one surface of the insulating substrate of the printed wiring substrate, and the adhesive layer is formed on the other surface. In addition, an outflow prevention portion for preventing outflow of the conductive member constituting the via is formed on the other surface of the insulating base material. For this reason, when a plurality of printed wiring bases are heated and pressed, the conductive member constituting the via is prevented from flowing out and diffusing into the adhesive layer by the outflow preventing portion. As a result, the conductive member does not approach other circuits of the printed wiring substrate, and the connection reliability of the interlayer connection can be improved.

  In one embodiment of the present invention, the outflow prevention part is formed of an insulating resin material. In another embodiment of the present invention, the outflow prevention part is formed of a metal material.

  In the method for manufacturing a multilayer printed wiring board according to the present invention, a plurality of printed wiring base materials in which a conductor circuit layer is formed on an insulating base material are stacked through an adhesive layer, and the insulating base material and the adhesive layer are penetrated in the stacking direction. A method of manufacturing a multilayer printed wiring board in which the conductor circuit layers are connected to each other through vias, wherein the conductor circuit layer is formed on a first surface of a first insulating base material, and the first insulating base material is formed. An outflow prevention portion is formed at a position corresponding to the conductor circuit layer on the second surface opposite to the first surface, and the outflow prevention portion is formed from the second surface of the first insulating base. Forming a via hole penetrating to reach the conductor circuit layer, filling the via hole of the outflow prevention part and the first insulating base material with a conductive member, and forming the via of the first insulating base material; Forming the adhesive layer on the second surface, the front side of the first insulating substrate; Laminating the second insulating base material via an adhesive layer, characterized in.

  According to the method for manufacturing a multilayer printed wiring board according to the present invention, the conductor circuit layer is formed on one surface of the insulating substrate of the printed wiring substrate, and the adhesive layer is formed on the other surface. In addition, since the outflow prevention part that prevents the outflow of the conductive member constituting the via is formed on the other surface of the insulating base material, as described above, when a plurality of printed wiring base materials are heated and pressed The conductive member constituting the via is prevented from flowing out and diffusing into the adhesive layer by the outflow preventing portion. As a result, a multilayer printed wiring board capable of improving the reliability of interlayer connection can be manufactured.

  According to the present invention, the flow of the conductive paste can be effectively suppressed at the time of lamination, and the reliability of interlayer connection can be improved.

It is sectional drawing which shows the structure of the multilayer printed wiring board which concerns on the 1st Embodiment of this invention. It is sectional drawing which shows the manufacturing process order of the multilayer printed wiring board. It is sectional drawing which shows the structure of the multilayer printed wiring board of the comparative example. It is sectional drawing which shows the structure of the multilayer printed wiring board which concerns on the 2nd Embodiment of this invention. It is sectional drawing which shows the manufacturing process order of the multilayer printed wiring board. It is sectional drawing which shows the structure of the multilayer printed wiring board which concerns on the 3rd Embodiment of this invention. It is sectional drawing which shows the manufacturing process order of the multilayer printed wiring board.

  Hereinafter, a multilayer printed wiring board and a method for manufacturing the same 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 multilayer printed wiring board 100 according to the first embodiment of the present invention. The multilayer printed wiring board 100 according to the first embodiment is formed by laminating a first printed wiring substrate 10 and a second printed wiring substrate 20. The first printed wiring board 10 includes a first insulating base 19, a first conductor circuit layer 11 formed on one surface 10 a of the first insulating base 19, and the other of the first insulating base 19. And an adhesive layer 9 formed on the surface 10b side. The first printed wiring board 10 includes vias 14 that are filled in via holes 13 that are formed through the first insulating base 19 in the stacking direction.

  The second printed wiring board 20 includes a second insulating base 29 and a second conductor circuit layer 12 formed on one surface 20 a of the second insulating base 29. The first and second conductor circuit layers 11 and 12 are electrically connected to each other through vias 14.

  An insulating layer 15 is formed on the surface 10 b of the first insulating base 19 so as to surround the periphery of the via 14. The insulating layer 15 is formed of, for example, a resin material and extends along the surface 10 b of the first insulating base material 19, and is formed to penetrate with the same diameter as the first insulating base material 19 to form a part of the via hole 13. ing. The insulating layer 15 has a function of preventing the conductive paste constituting the via 14 from flowing out and diffusing into the adhesive layer 9.

  The first and second insulating base materials 19 and 29 are made of, for example, a resin film having a thickness of about 25 μm. As the resin film, for example, a resin film made of thermoplastic polyimide, polyolefin, liquid crystal polymer, or the like, or a resin film made of a thermosetting epoxy resin can be used.

  The via 14 is made of a conductive material such as a conductive paste filled in the via hole 13. The conductive paste is, for example, one or more types of low electrical resistance metal particles selected from nickel, gold, silver, zinc, aluminum, iron, tungsten, etc., and one or more types of low selected from bismuth, indium, lead, etc. Metal particles having a melting point. 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.

  In the conductive paste thus configured, for example, the contained tin and the low melting point metal can be melted at 200 ° C. or less to form an alloy, and particularly an intermetallic compound can be formed with copper or silver. It has the characteristics that can be done. Note that the conductive paste can also be formed of a nanopaste in which fillers such as gold, silver, copper, and nickel having a nanometer particle size are mixed with the binder component as described above. In addition, the conductive paste can also be composed of 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 metal particles come into contact with each other.

  As a method for filling the conductive paste, a printing method, a spin coating method, a spray coating method, a dispensing method, a laminating method, a method using these methods together, and the like can be used.

  The first and second conductor circuit layers 11 and 12 have a thickness 10 that is patterned on the surfaces 10a and 20a of the first and second insulating bases 19 and 29 by a method such as photolithography, printing, or inkjet. It consists of a conductor layer (conductive member) such as copper of about 20 μm.

[Production method]
The multilayer printed wiring board 100 configured as described above is manufactured, for example, as follows. FIG. 2 is a cross-sectional view showing the multilayer printed wiring board in the order of the manufacturing process.

  First, the 1st insulating base material 19 with which conductor layers, such as copper foil, were formed on the surface 10a is prepared. As the 1st insulating base material 19 in which the conductor layer was formed, a single-sided copper clad laminated board (single-sided CCL) etc. can be used, for example. Next, a mask material is deposited on the conductor layer and exposed to light and developed to be processed into a desired pattern. Then, etching is performed to remove the mask material on the first conductor circuit layer 11 to form a patterned first conductor circuit layer 11 as shown in FIG.

  Next, as illustrated in FIG. 2A, the insulating layer 15 is formed on the surface 10 b of the first insulating base 19 at a place where a via corresponding to the first conductor circuit layer 11 is to be formed. About the film thickness of the insulating layer 15, it sets to the film thickness which can suppress the flow to the contact bonding layer of an electrically conductive paste at the time of adhesion | attachment. Moreover, the film thickness of the insulating layer 15 is set to be thinner than the thickness of the adhesive layer after bonding so that the bonding can be ensured. As a method for forming the insulating layer 15, for example, there are a method in which a resin is attached by photolithography using a photosensitive resin or an inkjet method, and is formed by heat or photocuring.

  Then, as shown in FIG. 2B, an adhesive layer 9 made of a polyimide adhesive film or the like is formed on the surface 10b opposite to the surface 10a on the first conductor circuit layer 11 formation side. The adhesive layer 9 may be composed of an adhesive film with a mask.

  Thereafter, as shown in FIG. 2C, for example, after the first insulating base 19 is inverted, the laser beam is irradiated from the laser irradiation device toward the first conductor circuit layer 11 on the surface of the first insulating base 19. Irradiation is performed on the adhesive layer 9 on the 10b side. As a result, a via hole 13 that penetrates the adhesive layer 9 and the insulating layer 15 and reaches the first conductor circuit layer 11 is formed in the first insulating base material 19. Thereafter, the smear is removed by a desmear process for removing the resin (smear) remaining on the inner wall of the via hole 13.

  Next, as shown in FIG. 2D, the via hole 13 is made of various solders, ACF, silver paste, a mixture of these pastes, or a paste material mixed with a small amount of different metals, as described above. Fill with conductive paste. Thereby, the via 14 in a state of filling the via hole 13 is formed.

  Then, as shown in FIG. 2 (e), the first printed wiring board 10 is separately formed on the surface 10b opposite to the surface 10a on the first conductor circuit layer 11 forming side of the first insulating base 19. The second printed wiring board 20 on which the second conductor circuit layer 12 is formed is placed so that the second conductor circuit layer 12 faces the end of the via 14 and heated and pressed. Thereby, as shown in FIG. 1, the multilayer printed wiring board 100 by which the 1st and 2nd printed wiring base materials 10 and 20 were laminated | stacked through the contact bonding layer 9 can be manufactured.

[effect]
Such a multilayer printed wiring board 100 has the following characteristics. FIG. 3 is a cross-sectional view showing the structure of the multilayer printed wiring board 101 of the comparative example. As shown in FIG. 3, in the multilayer printed wiring board 101 of the comparative example, the first conductor circuit layer 11 is formed on one surface 10a of the first insulating base material 19, and the adhesive layer 9 is formed on the other surface 10b. Is formed. A via hole 13 reaching the first conductor circuit layer 11 is formed in the first insulating base material 19, and a via 14 is formed by a conductive paste filled in the via hole 13.

  The surface 10 b of the first conductor circuit layer 11 is not formed with a configuration that suppresses the outflow of the conductive paste that forms the via 14. When the first printed wiring board 10 and the second printed wiring board 20 are heated and pressed in such a state, when the fluidity of the adhesive layer 9 is increased, the adhesive paste is applied from the adhesive layer 9 to the conductive paste of the via 14. There is a problem that the pressure is weakened and the conductive paste spreads. As shown by the symbol A in FIG. 3, when the conductive paste forming the via 14 spreads and the interval with another conductor circuit layer 11 ′ is narrowed, a defect such as migration occurs, and the connection reliability of the via 14 is improved. It drops significantly.

  On the other hand, as shown in FIG. 1, the multilayer printed wiring board 100 according to the first embodiment includes a first conductor circuit layer 11 on one surface 10 a of the first insulating base 19 of the first printed wiring base 10. And an adhesive layer 9 is formed on the other surface 10b. In addition, an insulating layer 15 is formed on the surface 10 b of the first insulating base 19 to prevent the conductive paste constituting the via 14 from flowing out.

  In the multilayer printed wiring board 100 according to the first embodiment, when the first printed wiring substrate 10 and the second printed wiring substrate 20 are heated and pressed, the conductive paste constituting the via 14 is formed by the insulating layer 15. Outflow / diffusion to the adhesive layer 9 is prevented. As a result, the conductive paste does not approach other circuits of the second printed wiring substrate 20, and the connection reliability of the interlayer connection can be improved. As described above, the multilayer printed wiring board 100 having the insulating layer 15 functioning as the outflow prevention unit can prevent the conductive paste from flowing out by heating and pressure bonding, and can obtain a substrate with high connection reliability.

[Second Embodiment]
FIG. 4 is a cross-sectional view showing the structure of a multilayer printed wiring board 200 according to the second embodiment of the present invention. The multilayer printed wiring board 200 according to the second embodiment has basically the same configuration as the multilayer printed wiring board 100 according to the first embodiment, but the material constituting the outflow prevention portion of the via 14 is the same. This is different from the first embodiment.

  In the present embodiment, the metal layer 16 is formed in order to prevent the conductive paste constituting the via 14 from flowing out. The thickness of the metal layer 16 is smaller than the thickness of the adhesive layer 9 after adhesion so that the flow of the conductive paste to the adhesive layer 9 can be suppressed and the adhesion can be ensured at the time of adhesion. Set as follows. Even with such a structure, the metal layer 16 is prevented from flowing out and diffusing into the adhesive layer 9 of the conductive paste constituting the via 14, and the first and second printed wiring substrates 10, 20 And the connection reliability of the interlayer connection between the second conductor circuit layers 11 and 12 can be improved.

[Production method]
The multilayer printed wiring board 200 configured in this way is manufactured, for example, as follows. FIG. 5 is a cross-sectional view showing the multilayer printed wiring board in the order of the manufacturing process.

  First, the 1st insulating base material 19 with which conductor layers, such as copper foil, were formed on the surfaces 10a and 10b is prepared. As the 1st insulating base material 19 in which the conductor layer was formed, a double-sided copper clad laminated board (double-sided CCL) etc. can be used, for example. Next, a mask material is deposited on the conductor layer on the surface 10a, and is processed by exposure / development so as to form a desired pattern. Etching is then performed to remove the mask material on the first conductor circuit layer 11 to form a patterned first conductor circuit layer 11 as shown in FIG.

  Next, as shown in FIG. 5A, a mask material is deposited on the conductor layer on the surface 10b, and is processed by exposure / development to obtain a desired pattern. Then, etching is performed to remove the mask material on the metal layer 16, and the metal layer 16 is formed at a location corresponding to the first conductor circuit layer 11 as shown in FIG.

  The manufacturing method of the multilayer printed wiring board shown in FIGS. 5B to 5E is the same as the manufacturing method of the first embodiment shown in FIGS. 2B to 2E. Therefore, the description is omitted here. Thereby, the multilayer printed wiring board 200 according to the second embodiment as shown in FIG. 4 can be manufactured.

[effect]
As shown in FIG. 4, in the multilayer printed wiring board 200 according to the second embodiment, the first conductor circuit layer 11 is formed on one surface 10 a of the first insulating base 19 of the first printed wiring base 10. The adhesive layer 9 is formed on the other surface 10b. Further, a metal layer 16 that prevents the conductive paste constituting the via 14 from flowing out is formed on the surface 10 b of the first insulating base material 19.

  Even in the multilayer printed wiring board 200 according to the second embodiment, when the first printed wiring substrate 10 and the second printed wiring substrate 20 are heated and pressed, the conductive paste constituting the via 14 is formed by the metal layer 16. Outflow / diffusion to the adhesive layer 9 is prevented. As a result, the conductive paste does not approach other circuits of the second printed wiring substrate 20, and the connection reliability of the interlayer connection can be improved. As described above, the multilayer printed wiring board 200 having the metal layer 16 functioning as the outflow prevention portion can prevent the conductive paste from flowing out by heating and pressure bonding, and can obtain a substrate with high connection reliability.

[Third Embodiment]
FIG. 6 is a cross-sectional view showing the structure of a multilayer printed wiring board 300 according to the third embodiment of the present invention. The multilayer printed wiring board 300 according to the third embodiment has basically the same configuration as the multilayer printed wiring boards 100 and 200 according to the first and second embodiments, but the outflow prevention portion of the via 14 Is different from the first and second embodiments.

  In the present embodiment, the adhesive layer 17 is formed as an outflow prevention portion that prevents the conductive paste constituting the via 14 from flowing out. The thickness of the adhesive layer 17 is not limited as long as the flow of the conductive paste to the adhesive layer 9 can be suppressed during adhesion, and may be a thickness that contacts the second conductor circuit layer 12 after adhesion. . Even with such a structure, the adhesive layer 17 prevents the conductive paste constituting the via 14 from flowing out and diffusing into the adhesive layer 9, and the first and second printed wiring substrates 10, 20 have the first. And the connection reliability of the interlayer connection between the second conductor circuit layers 11 and 12 can be improved.

[Production method]
The multilayer printed wiring board 300 configured as described above is manufactured, for example, as follows. FIG. 7 is a cross-sectional view showing the multilayer printed wiring board in the order of the manufacturing process.

  First, the 1st insulating base material 19 with which conductor layers, such as copper foil, were formed on the surface 10a is prepared. As the 1st insulating base material 19 in which the conductor layer was formed, a single-sided copper clad laminated board (single-sided CCL) etc. can be used, for example. Next, a mask material is deposited on the conductor layer and exposed to light and developed to be processed into a desired pattern. Etching is then performed to remove the mask material on the first conductor circuit layer 11 to form a patterned first conductor circuit layer 11 as shown in FIG.

  Next, as shown in FIG. 7A, the adhesive layer 17 is formed on the surface 10 b of the first insulating base material 19 at a place where a via corresponding to the first conductor circuit layer 11 is to be formed. The material of the adhesive layer 17 may be any material that can suppress the flow of the conductive paste during adhesion, and a material having a higher melting point than the material used for the adhesive layer 9 can be used.

  Then, as shown in FIG. 7B, an adhesive layer 9 made of a polyimide-based adhesive film or the like is formed on the surface 10b opposite to the surface 10a on the first conductor circuit layer 11 formation side. The adhesive layer 9 may be composed of an adhesive film with a mask.

  The manufacturing method of the multilayer printed wiring board shown in FIGS. 7C to 7D is the same as the manufacturing method of the first embodiment shown in FIGS. 2C to 2D. Therefore, the description is omitted here.

  Then, as shown in FIG. 7 (e), the first printed wiring board 10 is separately formed on the surface 10b opposite to the surface 10a on the first conductor circuit layer 11 forming side of the first insulating base 19; The second printed wiring board 20 on which the second conductor circuit layer 12 is formed is placed so that the second conductor circuit layer 12 faces the end of the via 14 and heated and pressed. At this time, since the adhesive layer 9 has a lower melting point than the adhesive layer 17, the fluidity at the time of pressure bonding is high. Therefore, the adhesive layer 9 under the adhesive layer 17 is all removed by flowing, and the adhesive layer 17 and the second conductor circuit layer 12 come into contact with each other. Even in this case, since the adhesive layer 17 has adhesiveness, the first printed wiring substrate 10 and the second printed wiring substrate 20 are securely bonded. Thereby, the multilayer printed wiring board 300 according to the third embodiment as shown in FIG. 6 can be manufactured.

[effect]
Even in the multilayer printed wiring board 300 according to the third embodiment, when the first printed wiring substrate 10 and the second printed wiring substrate 20 are heated and pressed, the conductive paste constituting the via 14 is formed by the adhesive layer 17. Outflow / diffusion to the adhesive layer 9 is prevented. As a result, the conductive paste does not approach other circuits of the second printed wiring substrate 20, and the connection reliability of the interlayer connection can be improved. Further, the first printed wiring substrate 10 and the second printed wiring substrate 20 are securely bonded by the adhesive layers 9 and 17. Thus, the multilayer printed wiring board 300 having the adhesive layer 17 functioning as an outflow prevention part can prevent outflow due to heating / compression of the conductive paste, and can obtain a substrate with high connection reliability.

  DESCRIPTION OF SYMBOLS 9 ... Adhesion layer, 10 ... 1st printed wiring base material, 11 ... 1st conductor circuit layer, 12 ... 2nd conductor circuit layer, 13 ... Via hole, 14 ... Via, DESCRIPTION OF SYMBOLS 15 ... Insulating layer, 16 ... Metal layer, 17 ... Adhesive layer, 19 ... 1st insulating base material, 20 ... 2nd printed wiring base material, 29 ... 2nd insulating base Material: 100, 200, 300: Multilayer printed wiring board.

Claims (4)

A plurality of printed wiring substrates, in which a conductor circuit layer is formed on an insulating substrate, are stacked via an adhesive layer, and the conductor circuit layers are connected to each other via vias penetrating the insulating substrate and the adhesive layer in the stacking direction. Multi-layer printed wiring board,
A multilayer printed wiring board comprising a conductive member outflow prevention portion on a contact surface between the insulating base and the adhesive layer. The multilayer printed wiring board according to claim 1, wherein the outflow prevention portion is formed of an insulating resin material. The multilayer printed wiring board according to claim 1, wherein the outflow prevention portion is formed of a metal material. A plurality of printed wiring substrates, in which a conductor circuit layer is formed on an insulating substrate, are stacked via an adhesive layer, and the conductor circuit layers are connected to each other via vias penetrating the insulating substrate and the adhesive layer in the stacking direction. A method for producing a multilayer printed wiring board, comprising:
Forming the conductor circuit layer on the first surface of the first insulating substrate;
Forming an outflow prevention portion at a position corresponding to the conductor circuit layer on the second surface opposite to the first surface of the first insulating base;
From the second surface of the first insulating base material, a via hole that penetrates the outflow prevention portion and reaches the conductor circuit layer is formed,
By forming a via by filling a conductive member into the via hole of the outflow prevention part and the first insulating substrate,
Forming the adhesive layer on the second surface of the first insulating substrate;
The method for producing a multilayer printed wiring board, wherein the first insulating base material is laminated on the second insulating base material through the adhesive layer.

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