JP2017168737A - Multilayer wiring board and manufacturing method of multilayer wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multilayer wiring board in which adhesion of a wiring layer of a via part is high.SOLUTION: A multilayer wiring board 1 is a multilayer wiring board in which a plurality of wiring layers 12, 22, and 32 and insulation layers 11, 21, and 31 are alternately laminated. The multilayer wiring board includes: at least one of via parts 3 connecting two or more wiring layers of a plurality of wiring layers, and a projection part 14 that is provided to at least one via part, and is made of an insulation material projected toward the wiring layer of the other end side of two or more wiring layers from the wiring layer 12 of one end side of two ore more wiring layers to be connected. A tip part of the projection part reaches to the wiring layer of the other end side of two or more wiring layers to be connected. In a conductive metal film 15 covering an external surface of the projection part, two or more wiring layers to be connected are conducted.SELECTED DRAWING: Figure 2

Description

  The present application relates to a multilayer wiring board and a method for manufacturing the multilayer wiring board.

  In a conventional multilayer wiring board, when two or more wiring layers are connected, a wiring layer located on one end side of the two or more wiring layers (for example, a lower wiring layer) is connected to an insulating layer between the wiring layers. ) To the wiring layer (for example, the upper wiring layer) located on the other end side, and a via portion is formed by inserting a metal into the hole to connect the wiring layers.

  FIG. 11 shows a cross-sectional view of a multilayer wiring board 101 made of a plurality of wiring layers (112, 122, 132) and insulating layers (111, 121, 131) manufactured by a conventional method. In the conventional multilayer wiring board 101, when a plurality of wiring layers are continuously connected to the same position, a hole 116 of a via portion 103 (stack via) is formed. As shown in FIG. 11, the hole 116 is formed so as to expand from the wiring layer 112 on one end side toward the wiring layer 132 on the other end side. That is, the hole 116 is narrowed according to the direction (direction of arrow A in FIG. 11) from the wiring layer 132 on the other end side to the wiring layer 112 on the one end side. Then, by inserting the metal 115 into the hole 116, each wiring layer is conducted. However, since the area of the joint portion 117 between the wiring layer 112 and the via portion 103 is narrow, for example, when stress is concentrated on the joint portion 117, the via portion 103 may be separated from the wiring layer 112.

JP-A-2-288395 JP 2001-345556 A JP 2002-26522 A

  In view of the above problems, an object of the present invention is to provide a multilayer wiring board having high adhesion between a wiring layer and a via portion.

  According to one embodiment, a multilayer wiring board in which a plurality of wiring layers and insulating layers are alternately stacked, and among the plurality of wiring layers, at least one via portion that connects two or more wiring layers; Provided in at least one via portion and projecting from the wiring layer on one end of the two or more wiring layers connected to the wiring layer on the other end of the two or more wiring layers A protrusion made of an insulating material, and the top of the protrusion reaches the wiring layer on the other end of the two or more connected wiring layers, and the conductive surface coated on the outer surface of the protrusion. Provided is a multilayer wiring board in which each of two or more wiring layers to be connected is conductive with a conductive metal film.

  According to another aspect, there is provided a method for manufacturing a multilayer wiring board including a via portion, wherein the first wiring layer is formed on the first insulating layer and connected to the via portion. Protruding parts made of an insulating material and having a bottom surface narrower than the land part are formed on the part, and a conductive metal film is formed on the outer surface of the projecting part and the land part to conduct to the first wiring layer. Form at least one set of an insulating layer and a wiring layer on one wiring layer, and further form a conductive metal film on the surface of the conductive metal film for each wiring layer to be electrically connected to each other. A method for manufacturing a multilayer wiring board is provided.

  The disclosed multilayer wiring board includes a protrusion having a top reaching the wiring layer on the other end side of two or more connected wiring layers, and each conductive metal film of the connected wiring layer is provided on the protrusion. Overlap. For this reason, for example, a bonding area between the conductive metal film of the wiring layer and the via portion is secured, the adhesion between the wiring layer and the via portion is increased, and there is an effect that peeling of the via portion is prevented.

It is a top view which shows the multilayer wiring board of an indication. (A) is a perspective view which shows the via part of a multilayer wiring board, (b) is sectional drawing along the II-II line of (a). It is a flowchart which shows the method of manufacturing a multilayer wiring board. (A) is a perspective view which shows a part of multilayer multilayer board | substrate to disclose in process S1 shown in FIG. 3, (b) is sectional drawing along the IV-IV line of (a). (A) is a perspective view which shows a part of multilayer multilayer board | substrate to disclose in process S2 shown in FIG. 3, (b) is sectional drawing along the VV line of (a). (A) is a perspective view which shows a part of disclosed multilayer wiring board in process S3 shown in FIG. 3, (b) is sectional drawing along the VI-VI line of (a). (A) is a perspective view which shows a part of multilayer multilayer board | substrate to disclose in process S4 shown in FIG. 3, (b) is sectional drawing along the VII-VII line of (a). (A) is a perspective view which shows a part of multilayer multilayer board | substrate to disclose in process S5 shown in FIG. 3, (b) is sectional drawing along the VIII-VIII line of (a). (A) is a perspective view which shows a part of multilayer multilayer board | substrate to disclose in process S6 shown in FIG. 3, (b) is sectional drawing along the IX-IX line of (a). It is sectional drawing of the multilayer wiring board which has a four-layer wiring layer and an insulating layer. It is sectional drawing which shows the conventional multilayer wiring board.

  Hereinafter, embodiments of the present application will be described in detail based on specific examples with reference to the accompanying drawings. In the following embodiments, the same or similar elements are denoted by common reference numerals, and these drawings are appropriately changed in scale for easy understanding.

  FIG. 1 is a plan view showing a multilayer wiring board 1 having three wiring layers and three insulating layers. Among the three wiring layers of the multilayer wiring board 1, a plurality of wiring layers 32 are arranged on a third wiring layer 32. Pads 2a to 2l are arranged. In the multilayer wiring board 1, the pads 2 d to 2 f are directly connected to the pads 2 j to 2 l by wirings 32 b provided on the third wiring layer 32 (wiring layer on the other end side), respectively. On the other hand, the pads 2a to 2c are temporarily connected to the first wiring layer 12 on the opposite side of the third wiring layer 32 of the multilayer wiring board 1 through the via portions 3a to 3f (an example of the wiring layer on one end side). Or it connects with the 2nd wiring layer 22 located between the 1st wiring layer 12 and the 3rd wiring layer 32, and connects with the pads 2g-2i. For example, the pad 2a is connected to the wiring 22b (shown by a one-dot chain line) of the second wiring layer 22 of which the via portions 3a and 3d are intermediate layers and the wiring 12b (shown by a dotted line) of the first wiring layer 12. By doing so, it is connected to the pads 2g and 2i. Thus, by using the via portions 3a to 3i, the pads 2a to 2l can be connected without crossing each other.

  FIG. 2 is an enlarged view showing only a portion of a via portion 3a (hereinafter simply referred to as a via portion 3) provided in the multilayer wiring board 1 of the present embodiment. The perspective view which expands and shows, (b) is sectional drawing along the II-II line of (a).

  As shown in FIGS. 2A and 2B, the multilayer wiring board 1 includes three wiring layers (a first wiring layer 12, a second wiring layer 22, and a third wiring layer 32) and three insulating layers. This is a multilayer wiring board in which layers (first insulating layer 11, second insulating layer 21, and third insulating layer 31) are alternately stacked. Although not shown, the third wiring layer 32 shown in FIGS. 2A and 2B is connected to the pad 2a, the second wiring layer 22 is connected to the pad 2g, and the first wiring layer 12 is the pad 2i. Connect to.

  As shown in FIG. 2B, the first wiring layer 12, the second wiring layer 22, and the third wiring layer 32 of the multilayer wiring board 1 are connected by the via portion 3. The via portion 3 is a protrusion that is provided on the first wiring layer 12 of the multilayer wiring board 1 so as to project from the first wiring layer side to the third wiring layer side (in the direction of arrow B in FIG. 2B). Part 14. The protrusion 14 is made of an insulating material, and the top 14a of the protrusion 14 is formed so as to reach the third wiring layer 32 of the connected wiring layers. The outer surface of the protrusion 14 is covered with a conductive metal film 15, and the conductive metal film 15 is connected to the land portion 12a of the first wiring layer. The conductive metal film 15 is overlaid with the conductive metal film 22 a of the second wiring layer 22. Further, the conductive metal film 32 a of the third wiring layer 32 overlaps with the top portion 14 a of the protrusion 14. The conductive metal film 15 of the via part 3 is connected to the land part 12 a of the first wiring layer 12 on the bottom side of the via part 3, and the land part 12 a is connected to the wiring 12 b of the first wiring layer 12. The conductive metal film 22a of the second wiring layer 22 is connected to the wiring 22b, and the conductive metal film 32a of the third wiring layer 32 is connected to the wiring 32b. Thereby, the 1st wiring layer 12, the 2nd wiring layer 22, and the 3rd wiring layer 32 conduct. In addition, by providing the protruding portion 14, the area of the joint portion 14b between the protruding portion 14 and the land portion 12a is secured. Furthermore, since the conductive metal film 15 overlaps the land portion 12a, a bonding area between the via portion 3 and the land portion 12a is ensured, and adhesion between the first wiring layer 12 and the via portion 3 is improved. Further, the conductive metal film 22 a of the second wiring layer 22 covers a part of the conductive metal film 15 of the first wiring layer 12, so that the junction area between the second wiring layer 22 and the via part 3 is covered. Is secured. Furthermore, since the conductive metal film 32a of the third wiring layer 32 covers a part of the conductive metal film 22a of the second wiring layer 22, the bonding area between the third wiring layer 32 and the via portion 3 is increased. Secured. Therefore, the adhesion between the wiring layer and the via part 3 is improved.

  Furthermore, since the respective conductive metal films 15, 22a, 32a of each wiring layer overlap so as to include the top part 14a of the protrusion 14, the conductive metal films 15, 22a, 32a cause the protrusion 14 to be the first wiring. It is pressed to the layer 12 side. Thereby, the adhesion between the first wiring layer 12 and the via part 3 is improved.

  As shown in FIG. 2B, the projecting portion 14 has an area of a cross section of the projecting portion 14 from the first wiring layer 12 toward the third wiring layer 32 (in the direction of arrow B in FIG. 2B). Is formed so as to be small. In the present embodiment, the conductive metal film 15 is formed by applying and baking a metal ink containing silver, copper, or the like. By forming the protrusions 14 in a tapered manner, the side portions of the protrusions 14 are inclined, and the metal ink sprayed when forming the conductive metal film 15 is likely to adhere to the outer surface of the protrusions 14. The metal ink may be a metal other than silver / copper as long as it is a conductive metal.

  Further, as shown in FIG. 2B, the projecting portion 14 has a cross-sectional area of the projecting portion 14 from the first wiring layer 12 toward the third wiring layer 32 (in the direction of arrow B in FIG. 2B). Has a stepped shape. Thereby, the metal ink at the time of forming the conductive metal film 15 is likely to adhere to the outer surface of the protrusion 14. In the present embodiment, one step is formed for each layer, but a plurality of steps may be formed for each layer.

  The protruding portion 14 has a bottom surface that is narrower than the land portion 12a of the first wiring layer 12 on which the protruding portion 14 protrudes. Further, when the conductive metal film 15 is formed around the land portion 12a, a predetermined thickness T1 is set so that the ink-like conductive metal film 15 (metal ink) does not spread beyond the land portion 12a. A blocking portion 13 having the following is provided. The thickness T1 of the blocking portion 13 is larger than the thickness T2 of the first wiring layer 12.

  The first insulating layer 11 of the multilayer wiring board 1 of the present embodiment is formed to be thicker than the other insulating layers 21 and 31, and serves as a substrate for the multilayer wiring board 1.

  Next, the manufacturing method of the multilayer wiring board 1 of this embodiment is demonstrated using FIGS. FIG. 3 is a flowchart showing the procedure of the method for manufacturing the multilayer wiring board 1. 4 to 9 are a perspective view and a sectional view showing a part of the multilayer wiring board 1 in each step shown in FIG.

  In this embodiment, the multilayer wiring board 1 is manufactured by an ink jet printing method. First, in step S1, as shown in FIG. 4, a wiring pattern is formed on the first wiring layer 12 on the first insulating layer 11 which is a substrate. As the wiring pattern, the first wiring layer 12 is formed with a land portion 12a having a predetermined area at a position where the via portion 3 is provided and a wiring 12b connected to the land portion 12a.

In step S2, a blocking portion 13 is formed on the outer peripheral portion of the land portion 12a of the first wiring layer 12, as shown in FIG. The blocking portion 13 is formed with a thickness T1 larger than the thickness T2 of the first wiring layer 12 by an ink jet printing method. By providing the blocking portion 13, it is possible to prevent the metal ink from flowing out from the land portion 12 a when the metal ink that becomes the conductive metal film 15 is applied to the outer surface of the protruding portion 14. The blocking portion 13 is made of an insulating material, and is formed using, for example, an immediately curable resin material. For example, when a resin that is cured by UV irradiation is used as the immediate curing resin material, the applied resin is irradiated with 1000 mJ / cm ^{2 with} a high-pressure mercury lamp and cured.

  In step S3, as shown in FIG. 6, the protrusion 14 is formed near the center of the land 12a. The protrusion 14 is made of an insulating material, and is formed by applying an immediately curable resin material by, for example, an ink jet printing method. The protrusion 14 is formed so that the top 14a of the protrusion 14 reaches the upper third wiring layer 32, in other words, the height H1 of the top 14a of the protrusion 14 from the land 12a (see FIG. 2). Ink jet printing and curing are repeated as necessary so that the height is higher than the upper surface of the third wiring layer 32. As shown in FIG. 6, the protrusion 14 is formed such that the area of the cross section decreases as it goes from the first wiring layer 12 to the third wiring layer 32, that is, the protrusion 14 is tapered. To do. Further, as shown in FIG. 6, when forming the protrusion 14, a step shape may be formed on the outer surface of the protrusion 14 so that the area of the cross section is reduced for each layer.

  The area of the cross section of the protrusion 14 is determined by the desired wiring density. As an example, it is a conventional via portion, where the joint portion (joint portion 117 in FIG. 11) with the lowermost wiring layer (wiring layer on one end side) is φ200 μm, the taper angle of the side portion of the protrusion is 70 °, In consideration of the fact that the insulating film thickness between layers is 20 μm and the joint portion of the wiring layer on the other end side causes printing misalignment, it is assumed that a via portion having a three-layer structure with a hole diameter +200 μm (radius +100 μm) is replaced. To do. In the conventional multilayer wiring board, a via portion of about φ630 μm is formed in the wiring layer on the other end side. If this is replaced with the projection shape which is the projection portion of the present embodiment, the projection portion 14 can be formed with about φ430 μm in the wiring layer 112 on one end side of the multilayer wiring board even when the same printing deviation amount is taken into consideration. It becomes. Therefore, the bonding area in the wiring layer on the one end side can be increased by about 4.6 times compared with the conventional one, thereby ensuring good adhesion.

  In step S4, as shown in FIG. 7, a metal ink is applied and baked on the outer surface of the protrusion 14 by an ink jet printing method to form the conductive metal film 15 of the via 3. When the metal ink is ejected, the metal ink adheres to the outer surface of the protrusion 14 and flows from the vicinity of the bottom of the protrusion 14 onto the land portion 12a. Thereby, the conductive metal film 15 that connects the first wiring layer 12 to the other second wiring layer 22 and the third wiring layer 32 is integrally formed. The metal ink is blocked by the blocking portion 13 formed in the step S2, thereby preventing leakage from spreading to an undesired portion, that is, the outside of the land portion 12a.

  The firing for metallizing the metal ink is performed in accordance with the metallization conditions of the metal ink. For example, baking is performed at about 150 ° C. for about 1 hour.

  In step S5, as shown in FIG. 8, the second insulating layer 21 is formed on the first wiring layer 12 by an ink jet printing method. The formation of the second insulating layer 21 is performed except for the via portion 3 so that the conductive metal film 22a of the second wiring layer 22 and the conductive metal film 15 of the via portion 3 can conduct.

  In step S6, as shown in FIG. 9, the conductive metal film 22a of the second wiring layer 22 and the wiring 22b connected thereto are formed by the ink jet printing method.

  In step S7, if the number of formed wiring layers does not reach the desired number of wiring layers, that is, if the wiring layer formed in step S6 is not the last wiring layer (“No” in step S7), the insulating layer (Step S5) and wiring layer formation (step S6) are repeated. When the desired number of wiring layers is reached, that is, when the formed wiring layer is the last wiring layer (“Yes” in step 7), the manufacturing of the wiring layer and the insulating layer to be connected is completed. In the present embodiment, a third insulating layer 31 and a third wiring layer 32 are further formed to complete the multilayer wiring board 1 shown in FIG.

  In the present embodiment, the multilayer wiring board 1 having three wiring layers and three insulating layers has been described. However, the via portion 4 includes four wiring layers (first wiring layer 12, first wiring layer) as shown in FIG. Second wiring layer 22, third wiring layer 32, fourth wiring layer 42) and four insulating layers (first insulating layer 11, second insulating layer 21, third insulating layer 31, fourth wiring layer 42) The insulating layer 41) may be applied to the multilayer wiring board 2 arranged alternately.

  The present application has been described in detail with particular reference to preferred embodiments thereof. For easy understanding of the present application, specific forms of the present application are appended below.

(Appendix 1) A multilayer wiring board in which a plurality of wiring layers and insulating layers are alternately laminated,
Among the plurality of wiring layers, at least one via portion connecting two or more wiring layers;
The one or more wiring layers provided in the at least one via portion and connected to one end of the wiring layer project from the wiring layer on the other end side of the two or more wiring layers. A projection made of an insulating material provided,
The top of the protrusion reaches the wiring layer on the other end side of the two or more wiring layers to be connected and is connected with the conductive metal film coated on the outer surface of the protrusion. A multilayer wiring board in which each of two or more wiring layers conducts.
(Supplementary note 2) The multilayer wiring according to supplementary note 1, wherein the protrusion is formed so that a cross-sectional area of the protrusion decreases from the wiring layer on the one end side toward the wiring layer on the other end side. Board.
(Supplementary note 3) The supplementary note 1 or 2, wherein the protruding portion has a step shape in which an area of a cross section of the protruding portion decreases from the wiring layer on the one end side toward the wiring layer on the other end side. Multilayer wiring board.
(Appendix 4) The conductive metal film of the interconnect layer other than the interconnect layer on one end side of the two or more interconnect layers to be connected is formed so as to cover the top of the protrusion, The multilayer wiring board in any one.

(Additional remark 5) It is a manufacturing method of a multilayer wiring board provided with a via part, Comprising: The 1st wiring layer is formed in the 1st insulating layer, and the land part of the 1st wiring layer connected with the via part A protrusion made of an insulating material and having a bottom surface narrower than the land, and a conductive metal film is formed on the outer surface of the protrusion and the land to conduct to the first wiring layer, At least one set of an insulating layer and a wiring layer is formed on the first wiring layer, and a conductive metal film is further formed on the surface of the conductive metal film for each wiring layer to be conducted. The manufacturing method of a multilayer wiring board which aims at electrical conduction.
(Appendix 6) In appendix 5, including forming a blocking portion having a predetermined height on the outer periphery of the land portion before applying a conductive metal film to the outer surface of the protrusion portion. The manufacturing method of the multilayer wiring board as described.

DESCRIPTION OF SYMBOLS 1, 1a Multilayer wiring board 2a-2l Pad 3, 3a-3f, 4 Via part 11 1st insulating layer (board | substrate)
DESCRIPTION OF SYMBOLS 12 1st wiring layer 12a Land part 12b, 22b, 32b Wiring 13 Blocking part 14 Protrusion part 14a Top part 14b Joining part 15, 22a, 32a Conductive metal film 21 2nd insulating layer 22 2nd wiring layer 31 Third insulating layer 32 Third wiring layer 41 Fourth insulating layer 42 Fourth wiring layer

Claims (6)

A multilayer wiring board in which a plurality of wiring layers and insulating layers are alternately laminated,
Among the plurality of wiring layers, at least one via portion connecting two or more wiring layers;
The one or more wiring layers provided in the at least one via portion and connected to one end of the wiring layer project from the wiring layer on the other end side of the two or more wiring layers. A projection made of an insulating material provided,
The top of the protrusion reaches the wiring layer on the other end side of the two or more wiring layers to be connected and is connected with the conductive metal film coated on the outer surface of the protrusion. A multilayer wiring board in which each of two or more wiring layers conducts.   2. The multilayer wiring board according to claim 1, wherein the projecting portion is formed so that an area of a cross section of the projecting portion decreases from the wiring layer on the one end side toward the wiring layer on the other end side.   3. The multilayer wiring board according to claim 1, wherein the protruding portion has a stepped shape in which a cross-sectional area of the protruding portion decreases from the wiring layer on the one end side toward the wiring layer on the other end side.   4. The conductive metal film of a wiring layer other than the wiring layer on one end side of the two or more wiring layers to be connected is formed so as to cover a top portion of the protruding portion. A multilayer wiring board according to the item. A method of manufacturing a multilayer wiring board having a via portion,
Forming a first wiring layer on the first insulating layer;
The land portion of the first wiring layer connected to the via portion is made of an insulating material and has a protruding portion having a bottom surface narrower than the land portion,
Forming a conductive metal film on the outer surface of the protrusion and the land, and conducting to the first wiring layer,
Forming at least one set of an insulating layer and a wiring layer on the first wiring layer;
A method of manufacturing a multilayer wiring board, wherein a conductive metal film is further formed on the surface of the conductive metal film for each wiring layer to be conducted to achieve conduction with each wiring layer.   The multilayer according to claim 5, further comprising: forming a blocking portion having a predetermined height on the outer periphery of the land portion before applying a conductive metal film to the outer surface of the protruding portion. A method for manufacturing a wiring board.

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