JP2003078068A - Wiring board and electronic device using the same - Google Patents

Abstract

(57) Abstract: Provided is a high-density wiring board in which signal transmission loss hardly occurs and desired electrical characteristics can be obtained even when an electrode pad interval is reduced. SOLUTION: A mounting portion 7a of an electronic component 7 provided in a predetermined region on a main surface of an insulating substrate 1 formed by laminating a plurality of insulating layers 1b, and connection of the electronic component 7 to a peripheral side in the mounting portion 7a. Electrode pads 4 arranged in a plurality of rows corresponding to the terminals at substantially equal intervals, and are formed by being attached from the mounting portion 7a to the peripheral side of the insulating substrate 1 and connected to each electrode pad 4 and mounted on the mounting portion 7a. And a lead line 5 drawn out from the center side electrode pad 4b between the first row of electrode pads 4a arranged on the most peripheral side, the lead line 5 is located at the center of the mounting portion 7a. In the region between the electrode pad 4b on the side and the electrode pad 4 in the adjacent row and in the region outside the electrode pad 4a in the first row, they are connected to the lower layer wiring conductor 2a via the through conductor 3a and are drawn out.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a single chip package (SCP) and a multi-chip package (MC).
The present invention relates to a wiring board as a package for housing electronic components for high-density wiring such as P) and an electronic device using the same.

[0002]

2. Description of the Related Art Today's electronic devices are required to be small, thin, lightweight, high-performance, high-performance, high-quality and highly reliable, as represented by mobile communication devices. Electronic devices mounted on equipment are also required to be smaller and have higher density. Therefore, wiring boards that make up electronic devices are also required to be smaller, thinner, and have multiple terminals.To achieve this, the width of conductor layers such as signal conductor layers must be narrowed and the distance between them must be narrowed. In addition, higher density wiring is achieved by further increasing the number of conductor layers and the diameter of the through conductor connecting the conductor layers.

A wiring board manufactured by adopting a build-up method is known as a wiring board capable of such high-density wiring. The build-up method, for example, on a composite insulating substrate by impregnating a reinforcing material such as glass cloth or aramid non-woven fabric with a thermosetting resin typified by an epoxy resin having heat resistance and chemical resistance, After the wiring conductor is sandwiched in between, an adhesive made of a thermosetting resin such as epoxy resin is applied to form an insulating layer, and after the insulating layer is heat-cured,
A laser is used to form a through hole with a diameter of approximately 30 to 200 μm in the insulating layer above the wiring conductor, after which the surface of the insulating layer is chemically roughened, and the through hole is formed using electroless copper plating and electrolytic copper plating. A conductor film is formed on the wiring conductors on the side surface and the bottom surface of the through hole to form a through conductor, and a wiring conductor to be connected to the through conductor is formed on the surface of the insulating layer, and further, an insulating layer and a through conductor / wiring conductor are formed. This is a method of manufacturing a wiring board by repeating the above procedure a plurality of times.

In such a wiring board, each electrode formed on the lower surface of the electronic component is solder-bumped on the electrode pad formed on the through conductor leading to the mounting portion of the electronic component such as a semiconductor element on the surface thereof. An electronic device is obtained by connecting through a conductive bonding material such as.

However, as the density of electronic parts increases and the number of electrodes thereof increases, it is becoming difficult to form the through conductors leading to the mounting parts of the electronic parts on the surface of the wiring board. Therefore, the through conductor is formed so that its surface is led out to the outside of the electronic component mounting portion on the surface of the wiring board, and the electrode pad formed in the electronic component mounting portion and the through conductor are connected by a lead wire. Is being done.

However, in such a wiring board as well, with the increase in the density and the number of terminals of electronic parts, the electrode pads connected thereto also have a multi-point grid pattern in which they are arranged in a plurality of rows at equal intervals. However, there is a problem that it is difficult to connect the lead lines to all the electrode pads. This is the lead wire for the electrode pad located on the center side among the electrode pads formed in the multi-point grid pattern,
This is to lead out to the outside of the electronic component mounting part through the gaps between the electrode pads located on the outer side, and as the number of arrayed electrode pads increases, many lead wires can pass through the gaps between the outermost electrode pads. It is due to disappearance.

In order to solve such a problem, Japanese Patent Laid-Open No.
In 2001-127192, it is proposed to thin only the portion of the lead line of the electrode pad located on the center side, which is formed in the gap between the electrode pads.

[0008]

[Problems to be Solved by the Invention]
In the wiring board described in the publication No. 01-127192, the density of electronic components and the increase in the number of terminals are further advanced, and when the lead wire is made finer and finer, the electric resistance of the lead wire increases and the signal However, there is a problem in that the desired electrical characteristics cannot be obtained due to the increased transmission loss.
On the contrary, if the wiring width is widened by giving priority to the electrical characteristics,
As described above, there is a problem in that the number of lead lines that can be passed between the electrode pads is reduced and wiring becomes impossible.

The present invention has been completed in view of the above problems in the prior art, and an object of the present invention is not to reduce the lead-out line width of the electrode pad even if the number of electrode pads is increased. An object is to provide a wiring board having a high-density wiring pattern with low transmission loss and an electronic device using the same.

[0010]

A wiring board of the present invention comprises a mounting portion for electronic parts provided in a predetermined region on a main surface of an insulating substrate formed by laminating a plurality of insulating layers, and a periphery inside the mounting portion. Electrode pads arranged in a plurality of rows at approximately equal intervals corresponding to the connection terminals of the electronic component on the side, and formed by being attached from the mounting portion toward the peripheral side of the insulating substrate, connected to each electrode pad, and mounted A lead-out line extending from the electrode pad on the center side of the mounting portion through the first row of electrode pads arranged on the most peripheral side, wherein the lead-out line extends from the electrode pad on the center side of the mounting portion. It is characterized in that it is connected to the wiring conductor in the lower layer and led out through the through conductor in the area between the electrode pad in the adjacent row and the area outside the electrode pad in the first row, respectively.

Further, the wiring board of the present invention is characterized in that, in the above structure, the width of the wiring conductor in the lower layer is set to be equal to or more than the width of the lead wire on the peripheral side of the insulating board from the electrode pad in the first row. is there.

Further, in the electronic device of the present invention, an electronic component is mounted on the mounting portion of the wiring board, and each connection terminal of this electronic component and each corresponding electrode pad are electrically connected. It is characterized by that.

According to the wiring board of the present invention, the lead wire is penetrated between the electrode pad on the central side of the mounting portion of the electronic component and the electrode pad of the adjacent row and in the area outside the electrode pad of the first row. Since it is connected to the wiring conductor in the lower layer via a conductor and is drawn out, even if the number of electrode pads increases, the number of lead lines does not decrease and wiring becomes impossible, and a wiring board that enables high-density wiring is provided. be able to.

Further, according to the wiring board of the present invention, the width of the wiring conductor in the lower layer is set to be equal to or more than the width of the lead wire on the peripheral side of the insulating substrate from the electrode pad in the first row. The electrical resistance of the lead wire can be greatly reduced as compared with the case where the lead wire is thinned so as to pass through the gap between the electrode pads, and as a result, a wiring board with a small signal transmission loss can be obtained.

Further, according to the electronic device of the present invention, an electronic component is mounted on the mounting portion of the wiring board, and each connection terminal of the electronic component and each corresponding electrode pad are electrically connected. Therefore, it is possible to provide an electronic component having a high-density wiring and excellent signal transmission characteristics.

[0016]

DETAILED DESCRIPTION OF THE INVENTION The present invention will now be described in detail with reference to the accompanying drawings. FIG. 1 is a sectional view showing an example of an embodiment in which the present invention is applied to a wiring board for mounting a semiconductor element and an electronic device mounting a semiconductor element on the wiring board, and FIG. 2 is a portion of the wiring board. It is a top view. In these drawings, 1 is an insulating substrate, 2 is a wiring conductor, 3a is a penetrating conductor, 4 is an electrode pad, and 5 is a lead wire. These mainly constitute the wiring substrate 6 of the present invention. The electronic device 8 of the present invention is obtained by mounting the semiconductor element 7 as an electronic component on the.

The insulating substrate 1 has a function as a supporting member for supporting the electronic component 7 and has a length and width of about 5 to 50 mm. In this example, the insulating substrate 1 has a plate-like core body insulating layer 1a. , A plurality of insulating layers 1b adhered to the upper and lower surfaces thereof.

The core insulating layer 1a has a function of imparting strength to the insulating substrate 1 and preventing warping, and a glass cloth in which glass fibers are woven lengthwise and widthwise is thermosettable with epoxy resin or bismaleimide triazine resin. A wiring conductor 2 is formed by impregnating a resin, and a wiring conductor 2 made of a thin film of copper, nickel, gold or the like is adhered and formed on the upper and lower surfaces thereof. Further, the core insulating layer 1a has a diameter of 0.1 to 1.0 m from the upper surface to the lower surface.
has a plurality of through holes 11 of about m, and
A through-hole conductor 12 made of a copper film is adhered to the inner wall of the through-hole 11, and the wiring conductors 2 on the upper and lower surfaces are electrically connected via the through-hole conductor 12.

The core insulating layer 1a is manufactured by thermosetting a sheet in which glass cloth is impregnated with an uncured thermosetting resin, and then drilling the sheet from the upper surface to the lower surface. . The wiring conductor 2 has a thickness of 3 to 50 μm on the entire upper and lower surfaces of the uncured sheet for the core insulating layer 1a.
A copper film having a thickness of m is deposited, and the copper film is etched after curing the sheet to form a predetermined pattern. Further, the through-hole conductor 12 is formed by forming the through-hole 11 in the core insulating layer 1a by using a drill or the like, and then plating the inner peripheral wall of the through-hole 11 with copper having a thickness of about 3 to 50 μm by a known plating method. It is formed by depositing a film.

Further, the core insulating layer 1a is filled with a resin column 13 made of a thermosetting resin such as an epoxy resin or a bismaleimide triazine resin inside the through hole 11. The resin column 13 is for closing the through hole 11 so that the insulating layer 1b can be formed directly above and directly below the through hole 11, and an uncured paste-like thermosetting resin is placed inside the through hole 11. It is formed by filling by a screen printing method, thermally curing it, and polishing the upper and lower surfaces thereof to be substantially flat. The insulating layer 1b is laminated on the upper and lower surfaces of the core insulating layer 1a including the resin columns 13.

The insulating layers 1b laminated on the upper and lower surfaces of the core insulating layer 1a are made of a thermosetting resin such as an epoxy resin or a bismaleimide triazine resin, and each has a thickness of 10 to 80.
It is about μm, and the diameter is 20 from the upper surface to the lower surface of each layer.
It has a through hole 3 of ˜100 μm. These insulating layers 1
b is to provide an insulation interval for wiring the wiring conductors 2 at high density. Then, the upper wiring conductor 2
By electrically connecting the wiring conductor 2 and the lower layer wiring conductor 2 through the through conductor 3a formed of a copper film formed on the inner wall of the through hole 3, a high-density wiring can be three-dimensionally formed.

Such an insulating layer 1b is formed by a conventionally known doctor blade method, and the uncured thermosetting resin film to be the insulating layer 1b is attached to the core conductor insulating layer 1a. To the upper and lower surfaces, heat-curing the same, and forming the through holes 3 by laser processing such as carbon dioxide laser, UV laser, excimer laser, etc., and further forming the wiring conductors 2 on the insulating layer 1b and the inside of the through holes 3. Through conductor 3a
After forming, the upper insulating layer 1b is sequentially stacked in the same manner to be laminated.

The insulating layer 1b is obtained by kneading, for example, a mixture of an epoxy resin, a thermoplastic resin, an elastomer, and an inorganic insulating filler to which a solvent is added to obtain a liquid varnish, and the liquid varnish is polyethylene terephthalate (PET).
The composition is applied on a release sheet and dried at a temperature of 60 to 100 ° C to form a film.

The wiring conductor 2 and the through conductor 3a are
The surface of the insulating layer 1b and the inside of the through hole 3 are immersed in a roughening solution such as an aqueous solution of permanganate to roughen, and then immersed in an aqueous solution of a palladium catalyst for electroless plating to expose the surface of the insulating layer 1b and the through hole. 3 Palladium catalyst is attached to the inside, and after that, about 30 is added to the electroless copper plating solution consisting of copper sulfate, Rossell salt, formalin, EDTA sodium salt, stabilizer, etc.
Immerse for a minute to deposit electroless copper plating of about 1 to 2 μm, then deposit a plating resistant resin layer on the electroless copper plating, and expose and develop the pattern shape of the wiring conductor 2 to electrolytic copper plating. Forming an opening for deposition,
After electrolytic copper plating is applied to the openings by immersing in an electrolytic copper plating solution containing sulfuric acid, copper sulfate pentahydrate, chlorine, brightener, etc. for several hours while applying a current of several A / dm ² .
Strip the anti-plating resin layer with sodium hydroxide, and
The electroless copper plating exposed by peeling off the plating resistant resin layer is removed by etching with a sulfuric acid-based aqueous solution such as sulfuric acid / hydrogen peroxide solution, and then the electroless copper plating layer is removed.

The thickness of the wiring conductor 2 and the through conductor 3a is 3 μm from the viewpoint of transmitting a high speed signal.
It is preferable that the wiring conductor 2 and the penetrating conductor 3a are adhered to the insulating layer 1b by applying no large stress to the wiring conductor 2 and the penetrating conductor 3a when the wiring conductor 2 and the penetrating conductor 3a are adhered to the insulating layer 1b. In order to make it difficult to peel from 1b, it is preferable to set it to 50 μm or less.

Then, a part of the wiring conductor 2 formed on the electronic component mounting portion 7a on the outermost surface of one side of the insulating layer 1b has a conductor bump 9 made of, for example, lead-tin on each electrode of the electronic component 7. A part of the wiring conductor 2 which forms the electrode pad 4 and the lead wire 5 for connection of the electronic component to be joined via the outermost layer of the insulating layer 1b is formed on the surface of the external electric circuit board. Each electrode (not shown) is connected via a conductor bump 9 made of, for example, lead-tin.

The exposed surfaces of the electrode pads 4 and the lead lines 5 have good wettability with solder and corrosion resistance in order to prevent their oxidation and corrosion and to improve the connection with the conductor bumps 9. Excellent plating layer of nickel, gold, etc. is deposited.

The electrode pad 4 formed on the electronic component mounting portion 7a has a diameter of about 50 to 300 μm.
The lead lines 5 are arranged in a plurality of rows at equal intervals, and the lead lines 5 have a width of about 20 to 100 μm and are formed by deposition from the electrode pads 4 toward the peripheral side of the insulating substrate 1. ing.

The lead wire 5 is led out from the electrode pad 4b on the center side of the mounting portion 7a through the first row of electrode pads 4a arranged on the most peripheral side, and at the center side of the mounting portion 7a. Between the electrode pad 4b and the electrode pad 4a, 4b in the adjacent row and in the region outside the electrode pad 4a in the first row are respectively connected to the wiring conductor 2a in the lower layer via the penetrating conductor 3 and are drawn out. . This is also important in the present invention.

According to the wiring board 6 of the present invention, the lead wire 5 is drawn from the electrode pad 4b on the center side of the mounting portion 7a through the first row of electrode pads 4a arranged on the most peripheral side, and the mounting portion is also formed. Electrode pad 4b on the central side of 7a
From the electrode pad 4a, 4b in the adjacent column and in the area outside the electrode pad 4a in the first column, the electrode pad is connected to the wiring conductor 2a in the lower layer via the penetrating conductor 3 and is drawn out. Wiring does not become impossible even if the number of 4 is increased, and the wiring board 6 capable of high-density wiring can be obtained. In addition, since it is not necessary to make the width of the lead wire 5 finer or thinner between the electrode pads 4a of the first row, the electrical resistance of the lead wire 5 does not increase and the signal transmission characteristics do not deteriorate.

Further, in the wiring board 6 of the present invention, it is preferable that the width of the wiring conductor 2a in the lower layer is equal to or larger than the width of the lead wire 5 on the peripheral side of the insulating substrate 1 from the electrode pad 4a in the first row. By setting the width of the wiring conductor 2a in the lower layer to be equal to or larger than the width of the lead wire 5 on the peripheral side of the insulating substrate 1 from the electrode pad 4a of the first row, the lead wire 5 is formed on the surface of the wiring substrate 1 in the first row of electrode pads 4a. The electrical resistance of the lead wire 5 can be greatly reduced as compared with the case where the lead wire 5 is drawn out by thinning it so as to pass through the gap between them, and as a result, the wiring board 6 with a smaller signal transmission loss can be obtained.

In the lead wire 5, as shown in the partial plan view of FIG. 2, the portion other than the lower layer wiring conductor 2a is formed on the surface of the insulating base 1. In this example, the lower layer wiring conductor 2a is formed by separating the lead wire 5 formed on the surface of the insulating substrate 1 from the single insulating layer 1b, but depending on the number of electrode pads 4. Is
The lower-layer wiring conductor 2a may be formed by separating the lead wire 5 formed on the surface of the insulating substrate 1 from the two or more insulating layers 1b. Further, the wiring conductor 2a in the lower layer is connected to the plurality of insulating layers 1b.
It may be formed on top.

The penetrating conductor 3a connecting the electrode pad 4, the lead wire 5, the lower layer wiring conductor 2a, and the lead wire 5 to the lower layer wiring conductor 2a forms the wiring conductor 2 and the penetrating conductor 3a on the insulating layer 1b. When performing, it may be formed in a predetermined position in advance.

Then, a part of the lead wire 5 formed outside the mounting portion 7a of the lead wire 5 is formed on the insulating layer 1b as a through conductor 3.
a. The wiring conductor 2, and the through-hole conductor 12 formed in the core insulating layer 1a, and the electrode pad for connection with the external electric circuit formed on the other surface of the wiring board 6 via the wiring conductor 2 electrically. By connecting, the wiring board 6 of the present invention is formed.

Thus, according to the wiring board 6 of the present invention,
Due to the above-mentioned configuration, even if the number of electrode pads 4 increases, wiring is not impossible, and the wiring board 6 capable of high-density wiring can be obtained. In addition, since it is not necessary to make the width of the lead wire 7 finer or thinner between the electrode pads 4a of the first row, the wiring is such that the electric resistance of the lead wire 7 does not increase and the signal transmission characteristic does not deteriorate. It can be the substrate 6.

The wiring board 6 of the present invention is not limited to the above-mentioned embodiment, and various modifications can be made without departing from the gist of the present invention. Layer 1b is laminated on the upper and lower surfaces of the core insulating layer 1a,
The wiring conductor 2 was formed on the insulating layer 1b.
b may be laminated only on one surface of the core insulating layer 1a. Further, in the above-mentioned example, the insulating substrate 1 is formed by laminating the insulating layer 1b on the core insulating layer 1a, but the insulating substrate 1 may be composed of only the core insulating layer 1a.

Next, the electronic device 8 of the present invention includes the wiring board 6
The electronic component 7 is mounted on the mounting portion 7a of the electronic component 7, and the electrodes of the electronic component 7 and the corresponding electrode pads 4 are electrically connected via the conductor bumps 9.

The conductor bump 9 is formed on the electrode pad 4 by a conductive material such as lead-tin, tin-zinc, tin-silver-bismuth alloy. Such a conductor bump 9 is formed by the method described below. First, a solder resist layer 14 having openings on the electrode pads 4 is applied to the surface of the wiring board 6 by using a conventionally known screen printing method. The solder resist layer 14 has a thickness of 10 to 50 μm, and contains a mixture of a photosensitive resin such as an acrylic modified epoxy resin and an initiator and 30 to 70% by weight of an inorganic powder filler such as silica or talc. It is made of an insulating material and has a function of preventing adjacent electrode pads 4 from being electrically short-circuited by the conductor bumps 9 and improving the bonding strength between the electrode pads 4 and the insulating substrate 1. Next, when the conductor bump 9 is, for example, a solder made of lead-tin, a solder paste made of lead-tin is screen-printed on the exposed electrode pad 4 of the solder resist layer 14 and passed through a reflow oven. As a result, it is fixedly formed on the electrode pad 4 in a hemispherical shape. The surface of the electrode pad 4 exposed on the surface of the wiring board 6 is coated with a metal such as nickel and gold having excellent conductivity and corrosion resistance to a thickness of 1 to 20 μm by plating. Oxidation and corrosion of the pad 4 can be effectively prevented, and the connection between the electrode pad 4 and the conductor bump 4 can be made good.

Thereafter, each electrode of the electronic component 7 is bonded to the electrode pad 4 via the conductor bump 9 to mount the electronic component 7, and the wiring board 6 and the electronic component 7 are bonded and fixed with the underfill material 15. Further, by sealing the electronic component 7 with a lid or potting resin (not shown), an electronic device 8 is formed, and the electrode pad on the opposite side of the mounting portion 7a of the electronic component 7 of the wiring board 6 from the external electric circuit board is formed. By electrically connecting to a wiring conductor (not shown), the electronic device 8 of the present invention is mounted on the external electric circuit board.

The solder resist layer 14 is formed by applying an uncured resin film made of a photosensitive resin, a photoinitiator and an inorganic powder filler, or an uncured resin varnish made of a thermosetting resin and an inorganic powder filler, or After laminating the uncured resin film, an opening is formed by exposure and development, and UV curing and heat curing are performed to apply the film.

Thus, according to the electronic device 8 of the present invention,
The electronic component 7 is mounted on the mounting portion 7a of the wiring board 6 described above,
Since each connection terminal of the electronic component 7 and each corresponding electrode pad 4 are electrically connected, it is possible to provide an electronic device having a high density of wiring and excellent signal transmission characteristics.

Needless to say, the wiring board and the electronic device of the present invention are not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the present invention.

[0043]

According to the wiring board of the present invention, the lead wire is provided between the electrode pad on the central side of the mounting portion of the electronic component and the electrode pad of the adjacent row and in the area outside the electrode pad of the first row. Since the wiring conductors are connected to the lower-layer wiring conductors via the through conductors and drawn out, wiring is not impossible even if the number of electrode pads is increased, and a wiring board capable of high-density wiring can be obtained.

Further, according to the wiring board of the present invention, the width of the wiring conductor in the lower layer is set to be equal to or more than the width of the lead wire on the peripheral side of the insulating substrate from the electrode pad in the first row. The electrical resistance of the lead wire can be greatly reduced as compared with the case where the lead wire is thinned so as to pass through the gap between the electrode pads, and as a result, a wiring board with a small signal transmission loss can be obtained.

Further, according to the electronic device of the present invention, an electronic component is mounted on the mounting portion of the wiring board, and each connection terminal of the electronic component and each electrode pad corresponding thereto are electrically connected. Therefore, it is possible to provide an electronic component having a high-density wiring and excellent signal transmission characteristics.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an example of an embodiment of a wiring board and an electronic device of the present invention.

FIG. 2 is a partial plan view of the wiring board of the present invention.

[Explanation of symbols]

1 ... Insulating substrate 1a --- Insulation layer for core 1b ... ・ ・ ・ Insulating layer 2 ・ ・ ・ ・ ・ ・ Wiring conductor 2a ... ・ ・ ・ Wiring conductor in the lower layer 3 ・ ・ ・ ・ ・ ・ Through hole 3a ... Penetration conductor 4 ... Electrode pad 4a ... the first row of electrode pads 4b ..... the electrode pad on the center side 5 ・ ・ ・ ・ ・ ・ Leader line 6 ・ ・ ・ ・ ・ ・ Wiring board 7 ・ ・ ・ ・ ・ ・ Electronic parts 7a ... Electronic component mounting part 8 ... Electronic device

Claims (3)

[Claims] 1. A mounting portion for an electronic component provided in a predetermined area on a main surface of an insulating substrate formed by laminating a plurality of insulating layers, and a connection terminal of the electronic component on a peripheral side in the mounting portion. And electrode pads arranged in a plurality of rows at substantially equal intervals, and are formed by being adhered from the mounting portion toward the peripheral side of the insulating substrate,
A wiring board connected to each of the electrode pads and extending from the electrode pad on the center side of the mounting portion through the first row of electrode pads arranged on the most peripheral side, The lead-out line is connected to the wiring conductor of the lower layer through the through conductors between the electrode pad on the center side of the mounting portion and the electrode pad of the adjacent column and in the region outside the electrode pad of the first column, respectively. A wiring board that is pulled out. 2. The wiring board according to claim 1, wherein the width of the wiring conductor in the lower layer is equal to or larger than the width of the lead line on the peripheral side of the insulating substrate from the electrode pad in the first row. 3. An electronic component is mounted on the mounting portion of the wiring board according to claim 1 or 2, and each connection terminal of the electronic component is electrically connected to each corresponding electrode pad. An electronic device characterized in that