JPH11289165A - Multilayer wiring board and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a multilayer wiring board wherein, comprising via connection of high reliability, high-density mounting and high density-wiring are allowed, and for simplifying the process. SOLUTION: A bump is provide at a first conductor layer, and a conductor layer 1b is laminated/allocated on a bump formation surface through an insulator layer 3. This is pressurized so that the tip end part of the bump is press- fitted/inserted into the insulator layer 3 for connection to the conductor layer 1b, thus forming a double-sided conductor layer core laminating plate. The double surface conductor layer of a core laminating body is patterned for wiring to form a core wiring board, and insulator layers 5a and 5b are formed on at least one main surface, forming connection via to the wiring pattern of the core wiring board. On the insulator layers 5a and 5b surfaces comprising it, conductive plating layers 6a and 6b are formed, which are patterned for wiring.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multilayer wiring board and a method of manufacturing the same, and more particularly to a multilayer wiring board capable of mounting and increasing the density of wiring patterns, and a method of easily manufacturing a multilayer wiring board.

[0002]

2. Description of the Related Art A multilayer wiring type wiring board has been widely put into practical use from the viewpoints of increasing the density, reducing the size, and increasing the functionality of a wiring circuit. In general, this type of multilayer wiring board is manufactured using a laminate made by laminating copper foil on both sides of an insulator layer as a raw material.

That is, through holes are drilled one by one at predetermined positions (predetermined positions) of the copper foil-clad laminate using, for example, an NC drilling machine, and the inner wall surfaces of the drilled holes are plated or the like. And electrically connect the copper foils on both sides. Thereafter, the copper foil on both sides is subjected to, for example, photoetching treatment and wiring patterning to obtain a double-sided wiring board.

In the case of a multilayer wiring board, (a) a glass-resin prepreg layer is interposed between the double-sided wiring boards, or (b) a double-sided wiring board is used as a core wiring board, It is manufactured by laminating a copper foil on the surface of a core wiring substrate via a glass / resin prepreg layer and laminating and integrating the copper foil.

[0005] Here, the manufacturing method of (b) laminating copper foil is also called a so-called build-up method, and specifically, it is performed as follows. First, a through hole connection type core wiring board is prepared, and an insulating resin is applied to the main surface of the core wiring board, or an insulating resin film is laminated and integrated to form an insulator layer.

After that, for connection to the wiring pattern of the core wiring board, a via is formed in the formed insulator layer, and then a conductive layer is formed on the surface of the insulator layer including the formed via inner wall surface by, for example, Cu plating. The film is coated. Next, the formed conductive film is subjected to, for example, a photo aging process, and wiring patterning for via connection to the wiring pattern of the core wiring substrate is performed. Formation of this insulator layer,
A required multilayer wiring board is manufactured by repeating via formation (perforation), covering of a conductor layer, and wiring patterning.

[0007]

However, the following inconveniences are recognized in the manufacture of a multilayer wiring board by the build-up method and the multilayer wiring board as a product. In other words, the wiring board in which the inner wall surface of the through hole is made conductive and electrically connected is used as a core, and an insulator layer is formed on the surface of the core wiring board, so that the through hole connection portion (hole / cavity) is left as it is. Or a concave surface due to inflow or depression of the insulating resin layer.

Therefore, when laminating a wiring pattern on the surface of the core wiring substrate via an insulating layer, the exposed portion of the insulating resin filling the through-hole connection portion of the core wiring substrate is polished and removed, or the through-hole is removed. A step of filling the hole forming the connection portion with an insulating resin or the like and making it flush with the surface of the core wiring board is required. In other words, the build-up method is expected to simplify the process and reduce the cost, but actually tends to complicate the process and increase the cost.

The present invention has been made in view of the above circumstances, and not only has a highly reliable via connection, but also has a multilayer wiring board capable of high-density mounting and high-density wiring, and a simplified process. It is an object of the present invention to provide a method of manufacturing a multilayer wiring board which can easily achieve the above.

[0010]

According to a first aspect of the present invention, there is provided a core wiring board which is connected through holes by conductive bumps into which an interlayer insulating layer is press-fitted and inserted, and at least one principal surface of the core wiring board is insulated. A multi-layer wiring board having a wiring pattern laminated and formed via a body layer and via-connected to a wiring pattern of a core wiring board, wherein the multi-layered wiring pattern has a plurality of layers. It is a wiring board.

According to a second aspect of the present invention, a step of providing a first conductive bump at a predetermined position on a first conductive layer;
Laminating and arranging a second conductive layer on the conductive bump forming surface via a first insulator layer, and pressing the laminated body so that the tip end of the first conductive bump is in contact with the first conductive bump. Forming a double-sided conductor-layered core laminate by press-fitting and inserting the above-mentioned insulator layer to the opposing second conductor layer; and wiring-patterning the double-sided conductor layers of the core laminate, respectively. Forming a core wiring board, forming an insulating layer on at least one main surface of the core wiring board, forming a via for connection to a wiring pattern of the core wiring board, forming the via A step of forming a conductive plating layer on an insulator layer surface including a portion, and a step of wiring-patterning the formed conductive plating layer.

In the first and second aspects of the present invention, the resin forming the insulator of the core wiring board and the interlayer insulator with the wiring pattern to be laminated is, for example, an epoxy resin, a phenol resin, a polyimide resin, a polycarbonate resin,
Hot melt adhesive, polyvinyl butyral resin, nitrile rubber, phenoxy resin, vinyl acetate resin, polyamide resin, polyamide imide resin, liquid crystal polymer, polyetheretherketone resin, polyetherimide resin, etc. Resin solution, or sheet (or film) in which the resin is combined with glass crusader, mat, synthetic fiber, cloth, etc.
One. And these resin-based sheets
For example, the thickness is about 50 to 150 μm, preferably about 80 to 120 μm.

In the first and second aspects of the present invention, the wiring pattern of the core wiring board is made of a conductive layer such as a copper foil, an aluminum foil, a nickel foil, a gold foil or a silver foil having a thickness of about 10 to 20 μm. And copper foil is suitable from the viewpoint of economy and workability.

In the configuration of the core wiring board,
The conductive bumps, which are press-fitted into the interlayer insulator and whose leading ends contact the surfaces to be connected of the wiring pattern facing each other and form electrical connection parts, are made of, for example, conductive powder such as Ag powder and binder such as epoxy resin. It is a conductive composition prepared with the components. The conductive bumps are produced by screen printing or the like of the conductive composition to form projections having a substantially constant height and shape, and drying and curing the projections.

In the first and second aspects of the present invention, the interlayer insulator for the core wiring board and the laminated wiring pattern is:
It is formed by application and drying of the resin solution, thermocompression bonding of the resin sheet, and the like. Here, the thickness of the interlayer insulator depends on the kind of the insulating resin, the capacity of the wiring, and the like, but is generally about 30 to 120 μm. In order to electrically connect vias between the wiring patterns to be laminated, a hole is formed at a predetermined position of the interlayer insulator. The hole is formed by, for example, laser processing.

According to the first and second aspects of the present invention, the wiring pattern laminated on the core wiring board surface has a thickness of, for example, 10%.
A conductive plating layer having a thickness of about 20 μm, for example, a wiring pattern of a copper plating layer, an aluminum plating layer, a nickel plating layer, a gold plating layer, or the like. Here, the plating layer may be formed by, for example, a combination of chemical plating and electroplating, or may have a configuration in which different types of metal layers are stacked. Further, the patterning of these conductor layers is generally a so-called photo-etching process, but may be a method by laser irradiation.

According to the first and second aspects of the present invention, since the core wiring substrate having the through hole connection portion formed in a filling manner is used, the insulating layer is laminated and coated for the laminated wiring on the surface of the core wiring substrate. In this case, even if other processing is not separately performed, there is no possibility of causing a partial concave surface or a change in thickness. In other words, highly reliable insulating properties and wiring patterns can be easily secured, and the conductive bumps can be miniaturized. A mounting type multilayer wiring board is provided.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, FIGS. 1A to 1C and FIG.
Embodiments will be described with reference to (a) to (e).

FIGS. 1A to 1C are cross-sectional views schematically showing an embodiment of a manufacturing example of a core wiring board used in this embodiment in the order of steps.

First, a copper foil 1a having a thickness of 18 μm is prepared, and an epoxy resin-based silver paste is printed and dried and solidified at a predetermined position on one main surface of the copper foil 1a to obtain a bottom diameter of 250 μm and a height of 150 μm.
An approximately conical conductive bump 2 'is formed. Thereafter, as shown in FIG. 1A, an 18 μm thick copper foil 1 b is laminated on the conical conductive bump 2 ′ forming surface via a glass epoxy resin prepreg 3 having a thickness of about 60 to 120 μm. .
Next, the laminate was integrated by applying heat and pressure, and the double-sided copper foil 1
a, 1b upholstered core laminate 4 'is produced. In this heat-pressing step, the tip of the conical conductive bump 2 ′ is press-fitted and inserted with a glass-epoxy resin prepreg 3, as shown in FIG.
As shown in FIG. 7, a double-sided copper-clad core laminate 4 ′ in which an electrical connection portion 2 is formed in contact with the opposed copper foil 1 b surface is manufactured.

Next, an etching resist (trade name, UV etching resist AS-400 made by Taiyo Ink KK) is printed on the copper foil 1a, 1b surface of the core laminate 4 'in a pattern by a screen printing method. Develop and provide an etching resist layer. Thereafter, the exposed copper foils 1a and 1b are selectively removed by etching using a cupric chloride bath, and then the etching resist layer is removed. As shown in FIG. A core wiring board 4 having required wiring patterns 1a 'and 1b' is manufactured.

FIGS. 2A to 2E show an embodiment of a manufacturing example of a multilayer wiring board in which wiring pattern layers are stacked and arranged on the surface of the core wiring board 4 by via connection using a build-up method.
It is sectional drawing which shows typically in a process order.

First, as shown in FIG. 2A, the thickness of each of the wiring patterns 1a 'and 1b'
An epoxy resin film having a thickness of about 50 to 100 μm is laminated, and this is thermocompression-bonded to integrally form the insulator layers 5a and 5b. The insulating layers 5a and 5b are coated with a resin solution, dried and dried.
A method in which the film is cured to form a film having a substantially uniform thickness may be employed.

Next, the insulator layers 5a, 5b corresponding to the via connections to the wiring patterns 1a ', 1b' of the core wiring board 4 will be described.
Laser processing is performed on the region 5b to open via connection portions 5a 'and 5b' as shown in FIG. 2B. Then, dipped in a chemical copper plating solution, as shown in FIG.
Insulator layers 5a, 5b including via connection parts 5a ', 5b' (openings)
After forming a copper plating layer on the surface, immerse it further in an electrolytic copper plating solution, grow and build up an electrolytic copper plating layer on the copper plating layer, and form a copper plating layer 6a, about 5 to 15 μm thick. 6b were each formed.

Next, an etching resist (trade name, UV etching resist AS-400 manufactured by Taiyo Ink KK) is printed in a pattern on the copper plating layers 6a and 6b formed by the screen printing method, and is exposed and developed. An etching resist layer is provided. Thereafter, the exposed copper plating layers 6a and 6b are selectively removed by etching using a cupric chloride bath, and then the etching resist layer is removed.
As shown in (1), a multilayer wiring board 7 having required wiring patterns 6a 'and 6b' on both sides is manufactured.

Further, in order to arrange a multilayer wiring pattern in a stacked manner, as shown in FIG. 2E, the multilayer wiring board 7 has a thickness of 50 μm on the surface on which the wiring patterns 6a ′ and 6b ′ are formed.
An epoxy resin film having a thickness of about 100 μm is laminated, and this is thermocompression-bonded to integrally form insulator layers 8a and 8b. Thereafter, by forming a via connection portion with respect to the insulator layers 8a and 8b, forming a copper plating layer, and patterning the copper plating layer according to the above, a target multilayer wiring board can be manufactured.

The multilayer wiring board having the through-hole connection 2 and the via connection 6a ', 6b' constructed by the above-mentioned build-up method is cut in the thickness direction, and each wiring pattern 1a ', 1b', 6 is cut.
connection state between a 'and 6b', connection portions 2, 6a 'and 6b'
Observation of the positional deviation and deformation state of each indicated that a good connection state and positioning were secured, and the resistance of each connection part was 2 mΩ on average.

Further, the wiring patterns 1a ', 1b', 6a ',
In order to evaluate the reliability of the joints 2, 6a ', 6b' between 6b ', one cycle of a hot oil test (one cycle of immersion in oil at 260 ° C for 10 seconds, immersion in oil at 20 ° C for 20 seconds) As a result, no defect was observed even after 100 times.

The present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, a paste containing copper powder (trade name, manufactured by DD Paste Tatsuta Electric Cable KK) or the like can be used as a conductive composition for forming a conductive bump, and a polyimide resin-based bonding film or the like can be used as an interlayer insulator. .

[0030]

According to the first and second aspects of the present invention, when laminating and covering an insulator layer for laminating wiring on the surface of a core wiring substrate, a partial concave surface can be obtained without performing another processing separately. The possibility of inconvenience such as change of thickness and change in thickness is also eliminated. In other words, the dense and reliable insulating properties and wiring patterns are easily secured as a whole, and the miniaturization of the conductive bumps is possible. A high-density wiring or a high-density mounting type multilayer wiring board is provided. In addition, since the process of flattening the core wiring substrate and the like are omitted, the manufacturing process is simplified, and productivity and yield can be improved.

[Brief description of the drawings]

FIGS. 1A, 1B, and 1C are cross-sectional views schematically illustrating a manufacturing example of a core wiring board used for a multilayer wiring board according to an embodiment in the order of steps.

FIGS. 2 (a), (b), (c), (d), and (e) are cross-sectional views schematically showing an example of manufacturing a multilayer wiring board according to an example in the order of steps.

[Explanation of symbols]

 1a, 1b: Copper foil 1a ', 1b', 6a ', 6b': Wiring pattern 2: Through hole connection of core wiring board 2 ': Conductive bump 3, 5a, 5b, 8a, 8b: Insulation Body layer 4 Core wiring board 5a ', 5b' Via connection opening 6a, 6b Copper plating layer 7 Multilayer wiring board

Claims (2)

[Claims] 1. A core wiring board connected through holes by conductive bumps into which an interlayer insulating layer is press-fitted and inserted, and a core laminated and formed on at least one principal surface of the core wiring board via an insulating layer. What is claimed is: 1. A multilayer wiring board, comprising: a wiring pattern connected to a wiring pattern of the wiring board via-connected to the wiring pattern, wherein the multilayered wiring pattern has a plurality of layers. A step of providing a first conductive bump at a predetermined position of the first conductive layer; and a step of forming a second conductive bump on the first conductive bump forming surface via a first insulator layer. Stacking and arranging a body layer, and pressing the stack to form a tip of the first conductive bump,
A step of press-fitting and inserting the first insulator layer to connect to the opposing second conductor layer to form a double-sided conductor layer-clad core laminate; wiring the double-sided conductor layers of the core laminate respectively Patterning to form a core wiring board; forming an insulating layer on at least one main surface of the core wiring board; forming a via for connection to a wiring pattern of the core wiring board; A method for manufacturing a multilayer wiring board, comprising: a step of forming a conductive plating layer on a surface of an insulator layer including a shaping portion; and a step of wiring-patterning the formed conductive plating layer.