JP2003168872A - Wiring board and electronic apparatus using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wiring board whose connection reliability of a wiring conductor to a through conductor is superior. <P>SOLUTION: The wiring board 5 is formed in such a way that a plurality of insulating layers 1 in which a glass fiber substrate is impregnated with a modified polyphenylene ether resin and a plurality of wiring conductors 2 composed of a metal foil are laminated alternately, and that the wiring conductors 2 situated in upper parts and lower parts by sandwiching the insulating layers 1 are electrically connected by through conductors 4 formed so as to be filled with a conductor. The content of the modified polyphenylene ether resin in the insulating layers 1 is 40 to 45 wt.%, and the through conductors 4 are arranged and installed in such a way that four to 12 pieces are distributed in the range within a radius of 500 μm. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has a structure in which a plurality of insulating layers and wiring conductors are alternately laminated, and wiring conductors located above and below the insulating layer are electrically connected by a through conductor provided in the insulating layer. And a electronic device using the same.

[0002]

2. Description of the Related Art Conventionally, as a wiring board used for mounting electronic parts such as semiconductor elements and resistors, a wiring consisting of an insulating layer made of a glass fiber base material and a modified polyphenylene ether resin and a metal foil such as a copper foil. A printed circuit board is known in which a plurality of conductors are alternately laminated. Such a printed circuit board is manufactured by etching a copper foil adhered to the surface of an insulating layer to form a wiring conductor, and laminating and pressing a plurality of insulating layers having the wiring conductor formed thereon to form a multilayer structure. There is.

However, since the surface of this printed circuit board becomes uneven due to the step between the wiring conductor portion and the non-wiring conductor portion on the surface of the insulating layer, the content of the modified polyphenylene ether resin is increased to 50 to 80% by weight. When an insulating sheet with a slight degree of plasticity is used as an insulating layer, when the wiring conductor is applied to the insulating sheet, the portion of the insulating sheet that abuts the wiring conductor is plastically deformed according to the thickness of the wiring conductor. Thus, the wiring conductor is embedded in the insulating sheet so that no unevenness is formed on the surface of the wiring board. The upper and lower wiring conductors of the printed circuit board are connected to each other through the through conductors formed in the insulating layer.

In such a wiring board, a through hole is formed by a laser in an insulating sheet in which a modified polyphenylene ether resin is impregnated in a glass fiber base material, and then a conductor made of metal powder and a thermosetting resin is provided in the through hole. The paste is filled by screen printing (press-fitting) to form a through conductor, while the transfer sheet base made of a heat-resistant resin is coated with copper foil and etched into a predetermined pattern to form a transfer sheet base. A wiring conductor is formed on the wiring conductor, and then the transfer sheet base material on which the wiring conductor is formed is press-contacted to the insulating sheet on which the penetration conductor is formed, so that the wiring conductor is transfer-embedded in the insulating sheet and connected to the penetration conductor. In addition, after peeling the transfer sheet base material from the insulating sheet, a plurality of insulating sheets having wiring conductors embedded therein are laminated, and the modified polyphenylene ether resin is applied by hot pressing. It is fabricated by integrating reduction.

[0005]

However, since the above wiring board has a large amount of the modified polyphenylene ether resin contained in the insulating layer of 50 to 80% by weight,
When the insulating layers are laminated and hot pressed, the heat of the hot pressing causes the modified polyphenylene ether resin to largely flow to the glass fiber substrate, and at the same time, the wiring conductor on the surface of the insulating layer is deformed or moved. , As a result, a position shift occurs between the through conductor and the wiring conductor connected to it,
There was a problem that a disconnection would occur.

The present invention has been completed in view of the above problems of the prior art, and an object thereof is to prevent positional deviation between a through conductor and a wiring conductor connected thereto when laminating and hot pressing. And a wiring board excellent in connection reliability and an electronic device using the same.

[0007]

A wiring board according to the present invention comprises an insulating layer in which a glass fiber base material is impregnated with a modified polyphenylene ether resin and a wiring conductor made of a metal foil, which are alternately laminated in plural layers. In the wiring board electrically connected by the through conductor formed by filling the through holes provided in the insulating layer between the wiring conductors located above and below the insulating layer, the insulating layer has a modified polyphenylene ether resin content of It is 40 to 45% by weight, and 4 to 12 through conductors are arranged so as to be distributed within a radius of 500 μm.

Further, the electronic device of the present invention is characterized in that an electronic component is mounted on the surface of the above-mentioned wiring board, and an electrode of this electronic component is electrically connected to a wiring conductor or a through conductor. It is a thing.

According to the wiring board of the present invention, since the content of the modified polyphenylene ether resin in the insulating layer is reduced to 40 to 45%, when the insulating layers are laminated and hot pressed,
The modified polyphenylene ether resin does not flow significantly against the glass fiber substrate due to the heat of the heat press,
Further, since the through conductors are arranged so as to be distributed in a range of 4 to 12 within a radius of 500 μm, the flow of the modified polyphenylene ether resin can be further suppressed by the anchor effect of the through conductor, and as a result, the insulating layer Deformation or movement of the wiring conductor on the surface does not occur, and there is no displacement between the through conductor and the wiring conductor connected to it, and excellent connection reliability without disconnection between the through conductor and the wiring conductor. It can be a wiring board.

According to the electronic device of the present invention, since the electronic component is mounted on the surface of the wiring board and the electrode of the electronic component is electrically connected to the wiring conductor or the through conductor, the through conductor is formed. And the wiring conductor connected to the wiring conductor can be reliably joined, and as a result, an electronic device having excellent connection reliability without disconnection between the through conductor and the wiring conductor can be provided.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a wiring board of the present invention and an electronic device using the same will be described in detail with reference to the accompanying drawings. FIG. 1 is a sectional view showing an example of an embodiment of an electronic device in which an electronic component such as a semiconductor element is mounted on a wiring board of the present invention, and FIG. 2 is formed on an insulating layer of the wiring board of the present invention. It is a top view which shows an example of the distribution state of the formed penetration conductor. In these figures, 1 is an insulating layer, 2 is a wiring conductor,
Reference numeral 3 is a through hole, and 4 is a through conductor, and these mainly constitute the wiring board 5 of the present invention. Reference numeral 6 denotes an electronic component, which mainly comprises the wiring board 5, the electronic component 6, and the electronic device of the present invention.

The insulating layer 1 has a thickness of 50 to 150 μm, has a function of supporting the wiring conductors 2 and maintaining insulation between the wiring conductors 2 positioned above and below, and a modified polyphenylene ether is added to the glass fiber base material. It is made by impregnating a resin.
If the thickness of the insulating layer 1 is less than 50 μm, the wiring board 5
Of the wiring board 5 tends to bend and warp easily, and when it exceeds 150 μm, the wiring board 5 becomes unnecessarily thick and it is difficult to reduce the weight. Therefore, the thickness of the insulating layer 1 is preferably 50 to 150 μm.

In the present invention, it is important that the content of the modified polyphenylene ether resin in the insulating layer 1 is 40 to 45% by weight. By reducing the content of the modified polyphenylene ether resin in the insulating layer 1 to 40 to 45%, when the insulating layer 1 is laminated and hot-pressed, the modified polyphenylene ether is added to the glass fiber substrate by the heat of the hot-pressing. The resin does not flow largely, and deformation and movement of the wiring conductor 2 on the surface of the insulating layer 1 described later and displacement of the through conductor 4 and the wiring conductor 2 connected thereto are suppressed, and the through conductor 4 and the wiring conductor are prevented. It is possible to improve the connection reliability with 2. If the content of the modified polyphenylene ether resin is less than 40% by weight, the glass fiber substrate is not sufficiently impregnated with the modified polyphenylene ether resin and voids are generated in the insulating layer 1, which causes a rapid reflow when mounting the electronic component 6. The heat history tends to cause swelling or peeling of the insulating layer 1. On the other hand, when it exceeds 45% by weight, the modified polyphenylene ether resin flows when the insulating layer 1 is laminated and hot pressed, and the surface of the insulating layer 1 The wiring conductor 2 of
There is a tendency that a positional shift occurs between the through conductor 4 and the wiring conductor 2 connected to the through conductor 4, causing disconnection. Therefore, it is important that the content of the modified polyphenylene ether resin in the insulating layer 1 is 40 to 45% by weight. In addition,
A crosslinking agent such as triallyl isocyanurate may be added to increase the crosslinking density of the modified polyphenylene ether resin.

A wiring conductor 2 is deposited / embedded on the surface of each insulating layer 1. The wiring conductor 2 has a function as a part of a conductive path that electrically connects each electrode of the electronic component 6 such as a semiconductor element mounted on the wiring board 4 to an external electric circuit board (not shown), Width 20-200μm, thickness 5-50
The thickness is μm and is made of a metal foil such as copper or aluminum / nickel / silver / gold. Particularly, from the viewpoint of workability and low cost, it is preferably made of a copper foil. If the width of the wiring conductor 2 is less than 20 μm, the wiring conductor 2 tends to be deformed or broken, and if it exceeds 200 μm, high density wiring cannot be formed. In addition, the thickness of the wiring conductor 2 is 5 μm
When it is less than 50 μm, the strength of the wiring conductor 2 is lowered and deformation or disconnection tends to occur.
Implantation tends to be difficult. Therefore, the wiring conductor 2 preferably has a width of 20 to 200 μm and a thickness of 5 to 50 μm.

Further, each insulating layer 1 is provided with a plurality of penetrating conductors 4 from its upper surface to its lower surface. These penetrating conductors 4 have a function of electrically connecting the wiring conductors 2 located above and below the insulating layer 1 and have a diameter of 30 to 100 μm.
m, which is formed by embedding a conductor made of a metal powder such as copper or silver-tin alloy and a triazine-based thermosetting resin in the through hole 3 provided in the insulating layer 1. If the diameter of the through hole 3 is less than 30 μm, its processing tends to be difficult, and if it exceeds 100 μm, high-density wiring cannot be formed. Therefore, it is preferable that the through hole 3 has a diameter of 30 to 100 μm.

Since the content of the modified polyphenylene ether resin in the insulating layer 1 is reduced to 40 to 45% by weight as described above, when the insulating layer 1 is laminated and hot pressed, the modified polyphenylene ether resin is Since the glass fiber base material is efficiently impregnated / compressed and cured, the metal powders of the through conductors 4 formed in the insulating layer 1 can be firmly connected to each other, and as a result, even if a long-term heat history is applied, The through conductor 4 having excellent connection reliability can be obtained.

It is important that such through conductors 4 are arranged so as to be distributed in a range of 4 to 12 within a radius of 500 μm. Put the through conductor 4 within a radius of 500 μm from 4 to 12
By arranging them so as to be distributed individually, the flow of the modified polyphenylene ether resin can be further suppressed by the anchor effect of the through conductors 4, and as a result, the wiring conductor 2 on the surface of the insulating layer 1 is deformed or moved. In addition, the through conductor 4 and the wiring conductor 2 connected to the through conductor 4 are not displaced from each other, and the wiring board 5 is excellent in connection reliability without disconnection between the through conductor 4 and the wiring conductor 2. it can. If the number of through conductors 4 is less than four within a radius of 500 μm from each of them, the anchor effect of the through conductors 4 is reduced, and the wiring conductors 2 on the surface of the insulating layer 1 are stacked when the insulating layers 1 are laminated and hot pressed. Of the through conductor 4 and the wiring conductor 2 connected to the through conductor 4 are displaced, and disconnection tends to occur. Therefore, the through conductor 4 is
It is important to dispose 4 to 12 distributions within a radius of 500 μm.

Such a wiring board 5 is manufactured by the method described below. First, an insulating sheet is manufactured by impregnating a glass fiber base material with a modified polyphenylene ether resin so that its content is 40 to 45% by weight and drying. Then, a through hole 3 having a diameter of 30 to 100 μm is formed at a predetermined position of the insulating sheet by using a conventionally known method such as a carbon dioxide laser or a YAG laser. At this time, the through holes 3 are arranged so that 4 to 12 through holes 3 are distributed within a radius of 500 μm. Then, the through-hole 3 is filled with a conductor paste containing a metal powder such as tin or copper and a thermosetting resin such as a triazine resin by a screen printing method (press-fitting) by using a conventionally known screen printing method. The through conductor 4 is formed by. After that, a separately prepared transfer sheet made of a heat-resistant resin such as polyethylene terephthalate (PET) resin, which has a wiring conductor 2 made of copper foil formed on a surface thereof in a predetermined pattern, is used as an insulating sheet, and a predetermined through conductor 4 is provided. And the wiring conductor 2 are aligned and overlapped so as to be connected to each other, and these are pressed at a temperature of 100 to 150 ° C. for several minutes by using a heat press machine to press the transfer sheet into contact with the insulating sheet, and thus the wiring conductor. 2 is transferred and embedded in an insulating sheet. Then, the transfer sheet is peeled off from the insulating sheet, a plurality of insulating sheets having the wiring conductors 2 embedded therein are stacked on top of each other, and hot-pressed at a temperature of 150 to 200 ° C. for several hours using a heat press machine. The wiring board 5 is manufactured.

Thus, according to the wiring board 5 of the present invention,
Since the content of the heat-modified polyphenylene ether resin in the insulating layer 1 is reduced to 40 to 45%, the flow of the modified polyphenylene ether resin can be suppressed when the insulating layer 1 is laminated and hot pressed, and the surface of the insulating layer 1 can be suppressed. The wiring conductor 2 can be prevented from being deformed, and the penetrating conductor 4 and the wiring conductor 2 connected thereto can be prevented.
And the position of the through conductor 4 is
Since 4 to 12 penetrating conductors 4 are arranged so as to be distributed within a range of 500 μm, the penetrating conductor 4 and the wiring conductor 2 connected thereto can be reliably joined by the anchor effect of the penetrating conductor 4. As a result, it is possible to obtain a wiring board having excellent connection reliability without breakage of the through conductor 4 and the wiring conductor 2.

Furthermore, a part of the wiring conductor 2 formed on the surface of one outermost layer of the insulating layer 1 is connected to each electrode of the electronic component 6 through the conductor bump 11 for mounting the electronic component 6 for mounting. A part of the wiring conductor 2 forming the electrode 2a and formed on the surface of the other outermost layer of the insulating layer 1 is connected to each electrode of the external electric circuit board (not shown) via the conductor bump 11. A mounting electrode 2b for external connection is formed.

The surfaces of the mounting electrodes 2a and 2b have good wettability with the conductor bumps 11 such as solder and corrosion resistance in order to prevent their oxidation and corrosion and to make a good connection with the conductor bumps 11. An excellent plating layer of nickel-gold or the like is deposited.

The outermost insulating layer 1 and the mounting electrodes 2a and 2b are covered with a solder-resistant resin layer 12 having an opening exposing the central portion thereof. The solder-resistant resin layer 12 is
From an insulating material having a thickness of 10 to 50 μm, for example, a mixture of a photosensitive resin such as an acrylic modified epoxy resin and a photoinitiator containing 30 to 70% by weight of an inorganic powder filler such as silica or talc. Negative, adjacent mounting electrode 2
It has a function of preventing electrical short-circuiting between the a and 2b due to the conductor bump 11 and improving the bonding strength between the mounting electrodes 2a and 2b and the insulating layer 1.

Such a solder-resistant resin layer 12 is formed by applying an uncured resin film composed of a photosensitive resin, a photoinitiator, and an inorganic powder filler to the surface of the outermost insulating layer 1, or a thermosetting resin. An uncured resin varnish consisting of an inorganic powder filler and an inorganic powder filler is applied to the surface of the outermost insulating layer 1 and dried, and then an opening is formed by exposure and development.
It is formed by UV curing and heat curing.

Thus, according to the electronic device of the present invention, the electronic component 6 is mounted on the surface of the wiring board 5 and the electrodes of the electronic component 6 are electrically connected to the wiring conductor 2 or the through conductor 4. , The through conductor 4 and the wiring conductor 2 connected to the through conductor 4 can be reliably joined, and as a result, the through conductor 4
It is possible to provide an electronic device having excellent connection reliability without disconnection between the wiring conductor 2 and the wiring conductor 2.

The present invention is not limited to the above-mentioned embodiments, and various modifications can be made without departing from the scope of the present invention. Although the case where the layers are laminated is shown as an example, the number of layers may be five or more.

[0026]

According to the wiring board of the present invention, the content of the modified polyphenylene ether resin in the insulating layer is reduced to 40 to 45%. The modified polyphenylene ether resin does not largely flow to the glass fiber base material due to heat, and the through conductor is 4 to 12 within a radius of 500 μm.
Since they are arranged so as to be distributed, the flow of the modified polyphenylene ether resin can be further suppressed by the anchor effect of the penetrating conductor, and as a result, the wiring conductor on the surface of the insulating layer may be deformed or moved, or There is no displacement between the conductor and the wiring conductor connected thereto, and a wiring board having excellent connection reliability without disconnection between the through conductor and the wiring conductor can be provided.

According to the electronic device of the present invention, since the electronic component is mounted on the surface of the wiring board and the electrode of the electronic component is electrically connected to the wiring conductor or the through conductor, the through conductor is formed. And the wiring conductor connected to the wiring conductor can be reliably joined, and as a result, an electronic device having excellent connection reliability without disconnection between the through conductor and the wiring conductor can be provided.

[0028]

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an example of an embodiment of an electronic device in which an electronic component such as a semiconductor element is mounted on a wiring board of the present invention.

FIG. 2 is a plan view showing an example of a distribution state of through conductors formed in an insulating layer of the wiring board of the present invention.

[Explanation of symbols]

1 ... Insulating layer 2 ... Wiring conductor 3 ... through holes 4 ... Penetration conductor 5 ··· Wiring board 6 ... Electronic parts

Claims (2)

[Claims] 1. A wiring conductor, wherein a plurality of insulating layers made of a glass fiber base material impregnated with a modified polyphenylene ether resin and a wiring conductor made of a metal foil are alternately laminated, and the wiring conductors are positioned above and below the insulating layer. In a wiring board which is electrically connected to each other by a through conductor formed by filling a through hole provided in the insulating layer with a conductor, the insulating layer has a modified polyphenylene ether resin content of 40 to 45% by weight. The wiring board is characterized in that 4 to 12 of the through conductors are arranged in a range of a radius of 500 μm or less. 2. An electronic device in which an electronic component is mounted on the surface of the wiring board according to claim 1, and an electrode of the electronic component is electrically connected to the wiring conductor or the through conductor. .