JP2012074519A - Multilayer printed board and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve reliability of electric connection between conductive layers.SOLUTION: A first conductive layer 3 formed on one surface 2a of a first insulation layer 2 is electrically connected to a second conductive layer 4 formed on the other surface 2b through a first interlayer connection part 7 formed by filling a conductive material 6 in a first via hole 5. A second insulation layer 2 is laminated on a surface of the first insulation layer 2 where the second conductive layer 4 is formed, and a third conductive layer 9 is formed on a surface of the second insulation layer 2, which is opposite to the first insulation layer 2. A second interlayer connection part 12 is formed by filling a conductive paste 11 in a second via hole 10 and a recessed part 7a formed in the first interlayer connection part 7, and the first to third conductive layers 3, 4, and 9 are electrically connected with each other through the first and second interlayer connection parts 7 and 12.

Description

  The present invention relates to a multilayer printed wiring board in which wiring patterns formed on a plurality of stacked insulating layers are electrically connected by interlayer connection and a method for manufacturing the same.

  Conventionally, in a multilayer printed wiring board, in order to electrically connect each wiring pattern insulated by an insulating layer, interlayer connection is made through a via hole penetrating the insulating layer and having a conductive material provided therein. In this interlayer connection structure, a method of filling a via hole formed in an insulating layer with copper plating or conductive paste as a conductive material is used. In particular, the interlayer connection method using the conductive paste is excellent in that the environmental load is small and the manufacturing method is simple.

  In this interlayer connection structure, a via hole is formed in an insulating layer by laser light, and a land portion of a circuit wiring by a metal foil and an interlayer connection portion by a plating layer are located on one side of the via hole, and a conductive paste is placed in the via hole. Is filled, and the interlayer connection portion by the conductive paste in the via hole and the interlayer connection portion such as the land portion of the circuit wiring of the other layer are further connected.

  As multilayer printed wiring boards having such an interlayer connection structure, there are those disclosed in Patent Documents 1 to 3.

  Patent Document 1 describes a flex-rigid board using a conductive paste as an interlayer connection material.

  Patent Document 2 discloses a multilayer in which via holes are formed with a laser beam in an insulating layer stacked on a conductive paste filled in a through hole for electrically connecting an inner layer wiring pattern, and the via holes are plated and interlayer connected. A printed wiring board is described.

  In Patent Document 3, a protruding portion of an interlayer conductive portion provided on one substrate is inserted into a recess formed in an interlayer conductive portion provided with metal plating in a via hole provided on the other substrate. Thus, there is described a multilayer wiring board which is electrically connected.

  In the multilayer printed wiring board as described above, various interlayer connection methods are used.

Japanese Patent No. 3744383 JP 2007-235165 A JP 2007-299943 A

  Accordingly, the present invention provides a novel interlayer connection method, and uses a cured conductive paste and an uncured conductive paste to improve the reliability of electrical connection between wiring patterns. It is an object of the present invention to provide a wiring board and a method for producing the multilayer printed wiring board.

  In the method for manufacturing a multilayer printed wiring board according to the present invention, a first via hole is formed in a first insulating layer, and a conductive material is filled in the first via hole and cured to form a first interlayer connection portion. Then, the first and second conductive layers formed on both surfaces of the first insulating layer are electrically connected by the first interlayer connection portion. Next, with the second insulating layer having the third conductive layer formed on one surface and the other surface facing the first insulating layer, the first interlayer connection portion of the first insulating layer is exposed. A second via hole is formed on the first insulating layer and the second conductive layer is formed on the first insulating layer and the third conductive layer is formed on the first interlayer connecting portion of the second insulating layer. A recess is formed in the surface on the insulating layer side of 2, and a conductive paste is filled in the recess in the second via hole and the first interlayer connection portion. Next, the second insulating layer and the conductive paste are heated and pressurized with respect to the first insulating layer and the first interlayer connection portion so that the first insulating layer and the second insulating layer are integrated and the conductive material is added. The adhesive paste is cured to form a second interlayer connection portion that electrically connects the first to third conductive layers together with the first interlayer connection portion.

  In the multilayer printed wiring board according to the present invention, the first conductive layer formed on one surface of the first insulating layer and the second conductive layer formed on the other surface are the first insulating layer. The first via hole penetrating therethrough is electrically connected by a first interlayer connecting portion formed by filling a conductive material, and is laminated on the surface of the first insulating layer on which the second conductive layer is formed. A third conductive layer is formed on a surface of the second insulating layer opposite to the first insulating layer, and the second via hole and the first interlayer connecting portion formed on the first interlayer connecting portion are formed. A second interlayer connection portion in which a conductive paste is filled in a recess formed on the second insulating layer side is formed, and the first to third conductive layers are electrically connected by the first and second interlayer connection portions. It is characterized by being connected.

  In the present invention, the first interlayer connection portion formed by filling the first via hole provided in the first insulating layer with the first conductive paste, and the second insulation provided on the first insulating layer. Filling the second via hole formed on the first interlayer connection portion of the layer and the concave portion formed on the second insulating layer side of the first interlayer connection portion with the second conductive paste, the first insulating layer When the second insulating layer and the second insulating layer are integrated by heating and pressing, the second conductive paste is pushed into the concave portion of the first interlayer connection portion and cured, so that the first interlayer connection portion and the second insulating layer are cured. Adhesiveness with the interlayer connection portion can be increased, and electrical connection reliability can be increased.

It is sectional drawing of the multilayer printed wiring board of 1st Embodiment manufactured by the manufacturing method of the multilayer printed wiring board to which this invention is applied. It is sectional drawing explaining the manufacturing method of the multilayer printed wiring board to which this invention is applied, (A) is sectional drawing of the 1st insulating layer in which the copper foil was provided in both surfaces and the 1st through-hole was formed. (B) is a cross-sectional view showing a state in which the first through-hole is filled with the first conductive paste, and (C) shows a state in which the first and second wiring patterns are formed. It is sectional drawing, (D) is sectional drawing which shows the state which laminated | stacked the 2nd insulating layer, (E) is sectional drawing which shows the state which formed the 2nd through hole. It is sectional drawing of the multilayer printed wiring board of 2nd Embodiment manufactured by the manufacturing method of the multilayer printed wiring board to which this invention is applied. It is sectional drawing of the flexible rigid wiring board manufactured by the manufacturing method of the flexible rigid wiring board to which this invention is applied. It is a manufacturing method of a buildup part, and is sectional drawing which shows the state which electrically connected the 1st and 2nd wiring pattern in the 1st insulating layer by the 1st interlayer connection part. It is sectional drawing which shows the state which laminated | stacked the 2nd and 3rd insulating layer on the 1st insulating layer. It is sectional drawing which shows the state which formed the 2nd via hole in the 2nd insulating layer. It is sectional drawing which shows the state which filled the 2nd conductive paste in the 2nd via hole. It is sectional drawing which shows the state after an external shape process. It is sectional drawing which shows the positional relationship of a core part and a buildup part.

  Hereinafter, a method for producing a multilayer printed wiring board to which the present invention is applied will be described in detail with reference to the drawings. As a first embodiment, a method of manufacturing a multilayer printed wiring board 1 (hereinafter, multilayer printed wiring board 1) composed of two layers to which the present invention is applied will be described. Prior to the description of the method for manufacturing the multilayer printed wiring board 1, the multilayer printed wiring board 1 manufactured by this manufacturing method will be described.

  As shown in FIG. 1, the multilayer printed wiring board 1 has a first wiring pattern 3 serving as a first conductive layer formed on one surface 2a of the first insulating layer 2, and a second wiring 2b formed on the other surface 2b. A conductive material in which the second wiring pattern 4 serving as a conductive layer is formed, and the land portion 3 a of the first wiring pattern 3 and the land portion 4 a of the second wiring pattern 4 are filled in the first via hole 5. The first conductive paste 6 is electrically connected by a first interlayer connection portion 7 formed by curing. In the multilayer printed wiring board 1, the second insulating layer 8 is laminated on the other surface 2 b of the first insulating layer 2, and the second insulating layer 8 is opposite to the first insulating layer 2. A third wiring pattern 9 serving as a third conductive layer is formed on the surface 8a, and the land portion 4a of the second wiring pattern 4 and the third wiring pattern 9 are connected to the first interlayer of the second insulating layer 8. The second via hole 10 formed on the connecting portion 7 is electrically connected by the second interlayer connecting portion 12 formed by filling the second conductive paste 11. In the multilayer printed wiring board 1, a recess 7 a is formed on the second interlayer connection portion 12 side of the first interlayer connection portion 7, and the second interlayer connection portion 12 is formed in the recess 7 a. The conductive paste 11 is filled.

  The multilayer printed wiring board 1 can be manufactured as follows.

  First, as shown in FIG. 2A, a first insulating layer 2 having a copper foil 20 provided on both sides is prepared. The first insulating layer 2 is excellent in heat resistance, mechanical strength, and electrical characteristics, and a double-sided copper-clad plate such as polyimide, epoxy resin, phenol resin, or BT resin can be used.

  Next, as shown in FIG. 2A, laser light L1 is irradiated from the other surface 2b side of the first insulating layer 2 on which the copper foil 20 forming the second wiring pattern 4 is formed. A first via hole 5 is formed. The first via hole 5 is formed at a position where the land portion 3 a of the first wiring pattern 3 and the land portion 4 a of the second wiring pattern 4 are electrically connected. At this time, the laser beam L1 is irradiated so that the copper foil 20 formed on the one surface 2a does not penetrate.

  Next, the inside of the first via hole 5 is subjected to a desmear process, and the first conductive paste 6 made of a conductive material is filled in the first via hole 5 in a vacuum as shown in FIG.

  The first conductive paste 6 is a material in which metal particles of a high melting point metal and a low melting point metal are mixed in a thermoplastic resin and alloyed by a subsequent heat treatment. For example, the refractory metal includes at least copper, and is a particle of copper alone or an alloy particle including copper and one or more metals of gold, silver, zinc, and nickel. The surfaces of these metal particles may be coated with gold, silver, zinc, nickel, or an alloy thereof by plating or the like. The average particle diameter of these metal particles is preferably 6 to 10 μm, for example 8 μm. The low melting point metal is Sn or metal alloy (for example, solder) containing Sn that diffuses at a low temperature. As the solder, Sn-Cu solder, Sn-Ag solder, Sn-Ag-Cu solder, any one or more of In, Zn, and Bi may be added to these solders, and further mixed as appropriate. . The binder resin of the first conductive paste 6 is a thermoplastic resin. For example, thermoplastic resins such as polyester, polyolefin, polyacryl, polyamide, polyamideimide, polyetherimide, polyphenylene ether, polyphenylene sulfide, and polyvinyl butyral can be used.

  As the filling method of the first conductive paste 6, a method such as printing such as screen printing or ink jet printing can be used. Moreover, the method of using a peelable film as a mask material and filling by squeeze can also be used.

  Further, the conductive material is not limited to the first conductive paste 6 but may be filled plating using copper or the like.

  Next, the first insulating layer 2 is hot-pressed to melt and cure the first conductive paste 6 to form the first interlayer connection portion 7, and the land portion 3 a of the first wiring pattern 3 and A portion to be the land portion 4a of the second wiring pattern 4 is connected.

  Next, as shown in FIG. 2C, a dry film of an etching resist is pasted on the copper foils 20 on the front and back surfaces for forming the first and second wiring patterns 3 and 4, and exposure to a predetermined circuit pattern is performed. Then, the first and second wiring patterns 3 and 4 are formed by etching. Thereby, the land portion 3 a of the first wiring pattern and the land portion 4 a of the second wiring pattern 4 are electrically connected via the first interlayer connection portion 7.

  Next, as shown in FIG. 2D, the second insulating layer 8 in which the copper foil 22 to be the third wiring pattern 9 is provided on one surface 8a is used, and the other surface 8b is used as the first insulating material. The first insulating layer 2 is placed on the layer 2 side. The second insulating layer 8 is a single-sided copper-clad plate formed of, for example, an epoxy resin and a curing agent, and for example, a B-stage state is used under conditions of 100 ° C. to 250 ° C. for 10 minutes or less. As the resin constituting the second insulating layer 8, polyethylene terephthalate, polyimide, phenol resin, BT resin, or the like can be used in addition to the epoxy resin. The second insulating layer 8 is not cured in the lamination step shown in FIG. 2D, and is in a B stage state.

  Next, as shown in FIG. 2E, the second via hole 10 is formed in the second insulating layer 8 and the copper foil 22 by laser light L2 using a carbon dioxide laser, YAG laser, excimer laser, or the like. At this time, the second via hole 10 is formed on the first interlayer connection portion 7 and the recess 7 a is formed in the first interlayer connection portion 7. Thus, the second via hole 10 and the recess 7a are formed by the laser beam L2, and the binder resin on the surface of the first conductive paste 6 is evaporated. Thereby, the first conductive paste 6 can easily form a metal bond with the second conductive paste 11 filled in the recess 7a. Further, since the surface of the first conductive paste 6 irradiated with the laser beam L2 is remelted to form an alloy layer having a high melting point, a concave portion 7a having a high thermal shock resistance can be formed.

  As another method, the second via hole 10 is formed in the second insulating layer 8 by opening the position where the second via hole 10 of the copper foil 22 is formed by etching and then irradiating the laser beam L2. You may make it do. Similarly to the first via hole 5, the surface of the second insulating layer 8 is also slightly cured in the second via hole 10 by the heat of the laser beam L2. Thereby, it is possible to prevent the second conductive paste 11 filled in the second via hole 10 from entering the second insulating layer 8 in a later step. Then, desmear processing is performed in the second via hole 10.

  Next, as shown in FIG. 1, the second conductive paste 11 is filled in the third wiring pattern 9, the second via hole 10, and the recess 7 a of the first interlayer connection portion 7. The second conductive paste 11 is the same as the first conductive paste 6 that constitutes the first interlayer connection portion 7 described above. The filling method of the second conductive paste 11 is also the same as that of the first conductive paste 6 described above. Note that the first conductive paste 6 and the second conductive paste 11 may be of different types.

Next, the first insulating layer 2 and the second insulating layer 8 are integrated. As a method of integration, the second insulating layer 8 is heated and pressed against the first insulating layer 2 at a predetermined temperature and pressure, and the first insulating layer 2 and the second insulating layer 8 are bonded together. And integrate. The integration conditions are, for example, a temperature of 170 ° C. to 250 ° C. and a pressure of ² to 6 MPa / cm ² for 10 minutes or more. When integrated, the second insulating layer 8 is compressed, so that the second conductive paste 11 filled in the second via hole 10 is pushed into the recess 7 a of the first interlayer connection portion 7. Cure in state. As a result, the second interlayer connection portion 12 is formed, and the second conductive paste 11 of the second interlayer connection portion 12 and the first conductive paste 6 of the first interlayer connection portion 7 are firmly formed without a gap. Bonding results in the formation of a metal bond, improving the electrical and mechanical strength between the layers.

  As shown in FIG. 1, the multilayer printed wiring board 1 in which the first wiring pattern 3 to the third wiring pattern 9 are electrically connected via the first and second interlayer connection portions 7 and 12. Can be manufactured.

  In the manufacturing method of the multilayer printed wiring board 1 as described above, the second insulating layer 8 filled with the second conductive paste 11 in the second via hole 10 is not cured, and the first insulating layer 2 is not cured. The first insulating layer 2 and the second insulating layer 8 are integrated by heating and pressurizing, whereby the second insulating layer 8 is compressed and the second via hole 10 is filled. The second conductive paste 11 is pushed into the recess 7 a of the first interlayer connection 7. Thereby, in the manufacturing method of the multilayer printed wiring board 1, the 2nd conductive paste 11 of the 2nd interlayer connection part 12 couple | bonds firmly with the 1st conductive paste 6 of the 1st interlayer connection part 7 without gap. In addition, a metal bond is formed, and interlayer connection strength can be improved. Therefore, the obtained multilayer printed wiring board 1 improves the reliability of electrical connection of the first wiring pattern 3 to the third wiring pattern 9.

  Further, in this method of manufacturing the multilayer printed wiring board 1, the conductor thickness can be reduced as compared with the plating, and the etch factor increases when the conductor thickness is thin, so that a fine pattern is easily formed.

  Furthermore, since this multilayer printed wiring board 1 manufacturing method is a dry process, the multilayer printed wiring board 1 can be manufactured without using water resources.

  Next, as a second embodiment, a double-sided multilayer printed wiring board 30 (hereinafter simply referred to as a multilayer printed wiring board 30) will be described as shown in FIG. In addition, about the structure similar to the multilayer printed wiring board 1 mentioned above, the same code | symbol is attached | subjected and detailed description is abbreviate | omitted.

  This multilayer printed wiring board 30 has a first wiring pattern 3 formed on one surface 2a of the first insulating layer 2 and a second wiring pattern 4 formed on the other surface 2b. 3 lands 3 a and the land 4 a of the second wiring pattern 4 are electrically connected by the first interlayer connection 7.

  The multilayer printed wiring board 30 includes a second insulating layer 8 formed on the second insulating layer 8 by laminating a second insulating layer 8 and a third wiring pattern 9 on the other surface 2 b of the first insulating layer 2. The first wiring pattern 3 to the third wiring pattern 9 are electrically connected by the interlayer connection portion 12. In this multilayer printed wiring board 30 as well, as in the multilayer printed wiring board 1 described above, the second conductive paste for forming the second interlayer connection portion 12 in the recess 7 a formed in the first interlayer connection portion 7. 11 is pushed in, the first interlayer connection 7 and the second interlayer connection 12 are firmly bonded without a gap, a metal bond is formed, and the interlayer connection strength is improved.

  The multilayer printed wiring board 30 has a multilayer structure in which a third insulating layer 31 and a copper foil 32 are laminated on one surface 2 a of the first insulating layer 2.

  As the third insulating layer 31, as with the second insulating layer 8, a single-sided copper-clad plate made of epoxy resin, polyethylene terephthalate, polyimide, phenol resin, BT resin, or the like can be used. The third insulating layer 31 protects the first wiring pattern 3 formed on one surface 2 a of the first insulating layer 2.

  The method for manufacturing the multilayer printed wiring board 30 includes a method for forming the first to third wiring patterns 3, 4, 9, a method for forming the first and second interlayer connection portions 7, 12, and the first insulating layer 2. And the second insulating layer 8 are integrated in the same manner as the multilayer printed wiring board 1 described above.

  The third insulating layer 31 faces the one surface 2 a of the first insulating layer 2, and together with the second insulating layer 8 or separately from the second insulating layer 8, the first insulating layer 31 is formed at a predetermined temperature and pressure. The insulating layer 2 is heated and pressed to be integrated with the first insulating layer 2 and the second insulating layer 8.

  Also in this multilayer printed wiring board 30, like the multilayer printed wiring board 1 described above, the first interlayer connection 7 and the second interlayer connection 12 are firmly bonded without a gap, and a metal bond is formed, Since the interlayer connection strength is high, the reliability of the electrical connection of the first wiring pattern 3 to the third wiring pattern 9 is high.

  Next, a flex-rigid printed wiring board 40 as shown in FIG. 4 will be described as a third embodiment. The flex-rigid printed wiring board 40 is formed with a first rigid portion 41, a second rigid portion 42, and a flexible flex portion 43.

  The 1st and 2nd rigid parts 41 and 42 consist of the structure where the 1st buildup part 51 and the 2nd buildup part 52 were laminated | stacked on both surfaces 53a and 53b of the flexible core part 53. As shown in FIG. The flex part 43 includes only the core part 53.

  The first build-up portion 51 has a first wiring pattern 62 formed on one surface 61a of the first insulating layer 61 and a second wiring pattern 63 formed on the other surface 61b. The first conductive paste 65 made of a conductive material filling the first via hole 64 formed in the first insulating layer 61 with the land portion 62a of the pattern 62 and the land portion 63a of the second wiring pattern 63 is cured. The first interlayer connection portion 66 formed in this way is electrically connected. In the first buildup part 51, the second insulating layer 67 is laminated on the other surface 61 b of the first insulating layer 61. The second insulating layer 67 is filled with a second conductive paste 69 filled in a second via hole 68 formed so as to face the first interlayer connection 66, and the second wiring pattern 63 and the core are filled. A second interlayer connection portion 70 that electrically connects the third wiring pattern 71 formed in the portion 53 is formed.

  Further, the first buildup portion 51 is formed in the third insulating layer 72 by laminating the third insulating layer 72 and the fourth wiring pattern 73 on one surface 61 a of the first insulating layer 61. By the third interlayer connection portion 75 made of the third conductive paste 74, the inner wiring pattern such as the first wiring pattern 62 and the second wiring pattern 63 and the fourth wiring pattern 73 are electrically connected. ing.

  The second buildup unit 52 is stacked on the core unit 53 so as to face the first buildup unit 51 through the core unit 53. Similar to the first buildup unit 51, the second buildup unit 52 includes fifth and sixth wiring patterns 77 and 78 formed on both surfaces 76 a and 76 b of the fourth insulating layer 76. They are electrically connected by a fourth interlayer connection portion 80 made of a conductive paste 79. A fifth insulating layer 81 is stacked on the other surface 76 b of the fourth insulating layer 76. In the fifth insulating layer 81, a fifth interlayer connection portion 83 made of the fifth conductive paste 82 is formed at a position facing the fourth interlayer connection portion 80. In the second buildup portion 52, the fourth and fifth wiring patterns 77 and 78 and the first surface formed on the outermost surface of the core portion 53 by the fourth interlayer connection portion 80 and the fifth interlayer connection portion 83. 7 wiring patterns 84 are electrically connected. A sixth insulating layer 85 and an eighth wiring pattern 86 are stacked on one surface 76 a of the fourth insulating layer 76, and the sixth interlayer connection portion 88 made of the sixth conductive paste 87 causes the Eight wiring patterns 86 and the wiring patterns formed in the inner layer are electrically connected.

  The core portion 53 of the first rigid portion 41 has a ninth wiring pattern 91 and a tenth wiring pattern 92 formed on a seventh insulating layer 90 made of a flexible flexible substrate. They are electrically connected by an eighth interlayer connection portion 94 made of paste 93. Further, an eighth insulating layer 95 and a third wiring pattern 71 serving as a cover lay are formed on one surface of the seventh insulating layer 90, and a ninth interlayer connection made of the ninth conductive paste 96 is formed. The third wiring pattern 71 is electrically connected to the ninth wiring pattern 91 and the tenth wiring pattern 92 by the portion 97 and the eighth interlayer connection portion 94. On the other surface of the seventh insulating layer 90, a ninth insulating layer 98 and a seventh wiring pattern 84 to be a cover lay are formed, and a tenth interlayer connection portion 100 made of a tenth conductive paste 99 is formed. The eighth wiring pattern 84 is electrically connected to the ninth wiring pattern 91 and the tenth wiring pattern 92 by the eighth interlayer connection portion 93.

  Similar to the first rigid portion 41, the second rigid portion 42 has a first buildup portion 51 laminated on one surface 53 a of the core portion 53, and a second buildup portion 52 on the other surface 53 b. Are stacked. The same reference numerals as those of the first rigid portion 41 are given and detailed description thereof is omitted.

  The flex part 43 has the same configuration as the core part 53 of the first rigid part 41.

  The flex-rigid printed wiring board 40 can be manufactured as follows. First, the manufacturing method of the 1st and 2nd buildup parts 51 and 52 is demonstrated. As shown in FIGS. 5 to 9, the first and second buildup parts 51 and 52 manufacture a multilayer printed wiring board having a three-layer structure, as in the multilayer printed wiring board 30 described above. Since the first buildup unit 51 and the second buildup unit 52 can be manufactured in the same manner, the first buildup unit 51 will be described, and the manufacturing method of the second buildup unit 52 will be omitted. To do.

  First, as shown in FIG. 5, the first wiring pattern 62 and the second wiring pattern 63 are formed by the first interlayer connection portion 66 made of the first conductive paste 65 formed in the first insulating layer 61. Connect electrically.

  Next, as shown in FIG. 6, the third insulating layer 61 is provided with a second insulating layer 67 on the other surface 61b of the first insulating layer 61 and a copper foil 72a on one surface 61a. A single-sided copper-clad plate to be 72 is placed. In the process shown in FIG. 6, the second insulating layer 67 and the third insulating layer 72 are in a B-stage state.

  Next, as shown in FIG. 7, the second via hole 68 and the second interlayer connection portion 66 in the second insulating layer 67 are opposed to the first interlayer connection portion 66 by laser light. A recess 66a is formed on the insulating layer 67 side. Thus, by forming the second via hole 68 with the laser beam, the recess 66a is formed and the binder resin on the surface of the first conductive paste 65 is evaporated. Thereby, the first conductive paste 65 easily forms a metal bond with the second conductive paste 69 filled in the recess 66a. Further, since the surface of the first conductive paste 65 irradiated with the laser light is remelted to form an alloy phase having a high melting point, a recess 66a having a high thermal shock resistance can be formed.

  Next, as shown in FIG. 8, a second conductive paste 69 is filled in the second via hole 68 and the recess 66a.

  Next, as shown in FIG. 9, the second conductive paste 69 and the second and third insulating layers 67 and 72 are uncured, and a router process is performed to a predetermined size. Thereby, the multilayer printed wiring board which consists of the 1st insulating layer 61 thru | or the 3rd insulating layer 72 of the 1st rigid part 41 and the 2nd rigid part 42 can be manufactured. In this step, not only the router processing but also the outer shape processing may be performed by a mold.

  Similarly, the fourth insulating layer 76 to the sixth insulating layer 85 of the first rigid portion 41 and the second rigid portion 42 are laminated, and the fourth interlayer connecting portion 80 and the fifth interlayer connecting portion 83 A multilayer printed wiring board in which the fifth wiring pattern 77 and the sixth wiring pattern 78 are electrically connected is manufactured.

  The core part 53 is manufactured in a separate process from the first buildup part 51 and the second buildup part 52. The core portion 53 electrically connects the ninth wiring pattern 91 and the tenth wiring pattern 92 formed on both surfaces of the seventh insulating layer 90 through the eighth interlayer connection portion 93. Next, an eighth insulating layer 95 is stacked on one surface of the seventh insulating layer 90, a third wiring pattern 71 is formed on the eighth insulating layer 95, and a ninth wiring layer is formed on the other surface. The insulating layer 98 is laminated, and the seventh wiring pattern 84 is formed on the ninth insulating layer 98 to manufacture the core portion 53.

  Next, as shown in FIG. 10, the first and second buildup parts 51 and 52 manufactured as described above are integrated with the core part 53.

  First, as shown in FIG. 10, the third wiring pattern 71 formed on the outermost surfaces 53 a and 53 b of the core portion 53 and the second conductive paste 69 forming the second interlayer connection portion 70 face each other. The second insulating layer 67 is formed on the eighth insulating layer 95 so that the fifth conductive paste 82 forming the seventh wiring pattern 84 and the fifth interlayer connecting portion 83 are opposed to each other. A fifth insulating layer 81 is stacked over the insulating layer 98.

  And the 1st and 2nd buildup parts 51 and 52 are heat-pressed with respect to the core part 53 with predetermined | prescribed temperature and pressurization, and the core part 53 and the 1st and 2nd buildup parts 51 and 52 are made. Integrate. When integrated, the second and fifth insulating layers 67 and 81, the second conductive paste 69, and the fifth conductive paste 82 are in an uncured state. The recess 66a of the first interlayer connection 66 and the fifth conductive paste 82 are pushed into the recess 80a of the fourth interlayer connection 80 and hardened. Thus, the second interlayer connection 70 and the fifth interlayer connection 83 are formed, and the first interlayer connection 66 and the second interlayer connection 70 are connected to the fourth interlayer connection 80 and the fifth interlayer connection 70. The interlayer connection portion 83 is firmly bonded without a gap, a metal bond is formed, and the interlayer connection strength is improved.

  Next, a fourth wiring pattern 73 is formed on the third insulating layer 72 of the first buildup portion 51, and an eighth wiring pattern is formed on the sixth insulating layer 85 of the second buildup portion 52. 86 is formed.

  In the manufacturing method of the flex-rigid printed wiring board 40 as described above, the first and second buildup portions 51 and 52 are formed in the concave portions 66a of the first interlayer connection portion 66 as in the multilayer printed wiring board 1 described above. In addition, since the second conductive paste 69 and the fifth conductive paste 82 are pushed into the recess 80a of the fourth interlayer connection 80, the first interlayer connection 66, the second interlayer connection 70, the second The fourth interlayer connection portion 80 and the fifth interlayer connection portion 83 can be firmly bonded without a gap and can be metal-bonded, and the interlayer connection strength can be improved. Therefore, in the obtained flex-rigid printed wiring board 40, the reliability of electrical connection of the first wiring pattern 62 to the tenth wiring pattern 92 is improved.

  In the manufacturing method of the flex-rigid printed wiring board 40, the first and second build-up parts 51 and 52 and the core part 53 can be produced in separate processes, so that the manufacturing lead time is shortened by about half. can do.

  In general, when a flex-rigid printed wiring board is manufactured by a build-up method, it is necessary to perform a window cutting process at a position where the flex portion 43 serving as a cable portion is located for each layer. In the method of manufacturing the printed wiring board 40, since the layers of the multilayer structure of the first and second buildup parts 51 and 52 are combined in advance, when the two parts of the core part 53 are integrated, each process is performed once. I can do it.

  Further, since the manufacturing method of the flex-rigid printed wiring board 40 is a dry process, the second insulating layer 67 and the fifth insulating layer 81 of the first and second buildup portions 51 and 52 are in the B stage state. Even so, the flex-rigid printed wiring board 40 can be manufactured without any problem.

  DESCRIPTION OF SYMBOLS 1 Multilayer printed wiring board, 2 1st insulating layer, 1st wiring pattern, 4 2nd wiring pattern, 5 1st via hole, 6 1st conductive paste, 7 1st interlayer connection part, 7a Recess, 8 2nd insulating layer, 9 3rd wiring pattern, 10 2nd via hole, 11 2nd conductive paste, 12 2nd interlayer connection part

Claims (18)

A first via hole is formed in the first insulating layer, a conductive material is filled in the first via hole, and cured to form a first interlayer connection portion, which is formed on both surfaces of the first insulating layer. Electrically connecting the first and second conductive layers at the first interlayer connection,
The surface of the first insulating layer on which the first interlayer connection portion is exposed, with the second insulating layer having the third conductive layer formed on one surface and the other surface facing the first insulating layer. Laminated to
A second via hole penetrating the second insulating layer and the third conductive layer is formed on the first interlayer connection portion of the second insulating layer, and the first interlayer connection portion Forming a recess in the surface on the second insulating layer side;
Filling the concave portion of the second via hole and the first interlayer connection portion with a conductive paste,
The second insulating layer and the conductive paste are heated and pressurized with respect to the first insulating layer and the first interlayer connection portion to integrate the first insulating layer and the second insulating layer. A multilayer printed wiring board comprising: curing the conductive paste to form the second interlayer connection portion that electrically connects the first to third conductive layers together with the first interlayer connection portion. Manufacturing method.   2. The method for manufacturing a multilayer printed wiring board according to claim 1, wherein the second insulating layer is in a B-stage state before being heated. The method for producing a multilayer printed wiring board according to claim 1, wherein the conductive paste contains tin as metal particles.   The method for producing a multilayer printed wiring board according to any one of claims 1 to 3, wherein the first insulating layer is polyimide and the second insulating layer is glass epoxy. A first conductive layer formed on one surface of the first insulating layer and a second conductive layer formed on the other surface are electrically connected in the first via hole penetrating the first insulating layer. Electrically connected by a first interlayer connection formed by filling the material,
A third conductive layer is formed on a surface of the first insulating layer opposite to the first insulating layer of the second insulating layer laminated on the surface on which the second conductive layer is formed; Second interlayer connection in which conductive paste is filled in a second via hole formed on the first interlayer connection and a recess formed on the second insulating layer side of the first interlayer connection Part is formed,
The multilayer printed wiring board, wherein the first to third conductive layers are electrically connected by the first and second interlayer connection portions.   The multilayer printed wiring board according to claim 5, wherein the conductive paste contains tin as metal particles.   The multilayer printed wiring board according to claim 5 or 6, wherein the first insulating layer is polyimide, and the second insulating layer is glass epoxy. In the manufacturing method of the multilayer printed wiring board in which the build-up part is laminated on the core part,
The build-up unit includes a first conductive layer formed on one surface of the first insulating layer and a second conductive layer formed on the other surface that penetrates the first insulating layer. Electrically connected by a first interlayer connection portion formed by filling a conductive material in the via hole of the first via layer, and the second insulating layer laminated on the surface on which the second conductive layer is formed. The conductive layer is filled with the second via hole formed on the first interlayer connection and the recess formed on the second insulation layer side of the first interlayer connection. A second interlayer connection is formed exposed from the second insulating layer;
The core part has a third conductive layer formed on the outermost surface of the core part,
The build-up part is laminated on the outermost surface of the core part so that the third conductive layer and the second interlayer connection part face each other, and the build-up part is heated and pressed against the core part. A method for producing a multilayer printed wiring board, which is integrated and electrically connects the first to third conductive layers by the first and second interlayer connection portions. The build-up portion forms the first via hole in the first insulating layer, fills the first via hole with the conductive material, and cures to form the first interlayer connection portion. Electrically connecting the first and second conductive layers provided on both sides of the first insulating layer at the first interlayer connection;
Laminating the second insulating layer on the surface of the first insulating layer where the first interlayer connection is exposed;
The second via hole penetrating the second insulating layer is formed on the first interlayer connection portion, and a recess is formed on the surface of the first interlayer connection portion on the second insulating layer side. ,
9. The method for producing a multilayer printed wiring board according to claim 8, wherein a conductive paste is filled in the second via hole and in the concave portion of the first interlayer connection portion.   The method for producing a multilayer printed wiring board according to claim 8 or 9, wherein the conductive paste contains tin as metal particles.   The method for manufacturing a multilayer printed wiring board according to any one of claims 8 to 10, wherein the build-up part is laminated on a part of the core part.   The core portion includes a plurality of build-up portions stacked on one surface, and a flexible portion where the build-up portions are not stacked is provided between the build-up portions. The manufacturing method of the multilayer printed wiring board of any one of Claim 8 thru | or 12.   The method for manufacturing a multilayer printed wiring board according to any one of claims 8 to 12, wherein the build-up part is laminated on both surfaces of the core part. In the multilayer printed wiring board in which the build-up part is laminated on the core part,
The build-up unit includes a first conductive layer formed on one surface of the first insulating layer and a second conductive layer formed on the other surface through the first insulating layer. The first interlayer connection portion formed by filling a conductive material in one via hole and electrically connected, and laminated on the surface of the first insulating layer on which the second conductive layer is formed The second insulating layer is filled with the conductive paste in the second via hole formed on the first interlayer connection and the recess formed on the second insulating layer side of the first interlayer connection. A second interlayer connection is formed,
The core portion has a third conductive layer formed on the outermost surface,
The build-up part is laminated and integrated on the outermost surface of the core part so that the third conductive layer and the conductive paste face each other, and the first to second interlayer connection parts make the first to A multilayer printed wiring board, wherein the third conductive layer is electrically connected.   The multilayer printed wiring board according to claim 14, wherein the conductive paste contains tin as metal particles.   The multilayer printed wiring board according to claim 14 or 15, wherein the build-up part is laminated on a part of the core part.   The core portion includes a plurality of build-up portions stacked on one surface, and a flexible portion where the build-up portions are not stacked is provided between the build-up portions. The multilayer printed wiring board according to any one of claims 14 to 16.   The multilayer printed wiring board according to any one of claims 14 to 17, wherein the build-up is laminated on both surfaces of the core portion.

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