JP2000013029A - High density wiring board, manufacturing method thereof, and electronic device using the same - Google Patents

Abstract

[PROBLEMS] To reduce the connection resistance of a bump on a high-density wiring board and to increase the wiring density by reducing a via hole for forming a bump. A high-density wiring board having a multilayer wiring structure in which a plurality of wiring boards are electrically connected to each other to form a single wiring board, and a semiconductor device such as a semiconductor package is mounted on the high-density wiring board. The wiring board includes a wiring pattern formed on the insulating film and a connection land electrically connected to the other wiring board, and a via hole for connecting to the other wiring board is formed on the insulating film immediately below the connection land. In the via hole, an interlayer connection protrusion formed of a linear protrusion of a conductor electrically connecting the connection lands of each wiring board is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a high-density wiring board,
The present invention relates to a technique which is effective when applied to an electronic device and a method for manufacturing a high-density wiring board using the same.

[0002]

2. Description of the Related Art In recent years, a high-density wiring board with multilayer wiring has been demanded in order to meet demands for thinner, higher density, and lower cost printed wiring boards.

As a conventional high-density wiring board, for example,
There is one using conductive via paste bumps, which was announced at the Circuit Packaging Society of 1996.

As shown in FIG. 12, a via hole is formed in a thermoplastic polyimide adhesive 5p and a polyimide film substrate 1p with copper circuit wiring, and a conductive via paste 4p and a connection land 2p are formed. This is a polyimide film multilayer wiring substrate 120 in which a plurality of films are collectively multilayered by hot melt.

[0005] This polyimide film multilayer wiring board 12
0 is manufactured using a copper / thermoplastic polyimide adhesive layer 5p.
A circuit wiring pattern is formed by a subtractive method on a four-layer polyimide film composed of (not shown) / polyimide film substrate 1p / thermoplastic polyimide adhesive layer 5p.

Next, using an excimer laser, a hole diameter of 120 mm is used.
A μm blind via is processed, and a conductive via paste 4p (conductive polyimide paste) is screen-printed and filled. Thus, a wiring board having the connection lands 2 on the blind via holes in which the bumps made of the conductive via paste are formed is formed.

[0007] The wiring substrate thus formed is aligned with another wiring substrate having connection lands 2p on the polyimide film substrate 1p, and 25 mm is pressed by a vacuum press.
Pressurize at a temperature around 0 ° C. As a result, the thermoplastic polyimide adhesive layer 5p of each film is hot-melt bonded to form the high-density wiring board 120 of multilayer wiring.

[0008]

SUMMARY OF THE INVENTION As a result of studying the above prior art, the present inventor has found the following problems.

In the conventional high-density wiring board, there is a problem that the connection resistance of the bump formed of the conductive via paste is 10 mΩ, which is a considerably high value.

Further, since the via holes for forming the bumps are formed by printing and filling the via holes with a conductive resin,
There is a problem with fillability and vias with a diameter of 0.3 mm are the smallest. As described above, since the via hole cannot be made small, there is a limit to an increase in the area in which the wiring can be formed, and there is a problem that the wiring density does not increase.

Further, since the bonding strength between the bump and the connection land by the conductive via paste is not large, there has been a problem that the connection resistance increases due to temperature cycling, high temperature storage and the like, and the reliability is low.

Accordingly, the present invention has been made to solve the above problems, and an object of the present invention is to provide a technique capable of reducing the connection resistance of a bump in a high-density wiring board.

Another object of the present invention is to provide a technique capable of increasing the wiring density by reducing the size of a via hole for forming a bump.

Another object of the present invention is to provide a technique capable of preventing an increase in connection resistance of a wiring board due to a temperature cycle, a high-temperature storage, or the like.

The above and other objects and novel features of the present invention will become apparent from the description of the present specification and the accompanying drawings.

[0016]

SUMMARY OF THE INVENTION Among the inventions disclosed in the present application, the outline of a representative one will be briefly described.
It is as follows.

In a high-density wiring board having a multilayer wiring structure in which a plurality of wiring boards are electrically connected to each other to form one wiring board, and a semiconductor device such as a semiconductor package is mounted, the plurality of wiring boards may be connected to each other. The board includes a wiring pattern formed on the insulating film and a connection land electrically connected to another wiring board, and a via hole for connecting to another wiring board is formed in the insulating film immediately below the connection land. And an inter-layer connection protrusion made of a conductor linear protrusion electrically connecting the connection lands of the respective wiring boards is provided in the via hole.

In an electronic device formed by mounting a semiconductor device on a wiring board, the wiring board may include a wiring pattern formed on an insulating film and a connection land electrically connected to another wiring board. A via hole for connecting to another wiring board is provided in the insulating film immediately below the connection land, and an interlayer connection comprising a conductor linear projection electrically connecting the connection land via the via hole. A high-density wiring board having a multilayer wiring structure having projections and electrically connecting a plurality of wiring boards to one wiring board is used.

Further, in a method of manufacturing a high-density wiring board having a multilayer wiring structure in which a plurality of wiring boards are electrically connected to each other to form a single wiring board, and on which a semiconductor device such as a semiconductor package is mounted. A first step of bonding a wiring material to an insulating film, a second step of forming a via hole in the insulating film for connecting to another wiring board, and patterning the wiring material to form a wiring pattern and other parts. Forming a connection land electrically connected to the wiring substrate, and forming an interlayer connection protrusion made of a linear protrusion of a conductor electrically connected to the connection land in the via hole. And a fifth step of electrically connecting the interlayer connection projections to connection lands of another wiring board, thereby manufacturing a high-density wiring board having a multilayer wiring structure.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the high-density wiring board of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram for explaining the configuration of a high-density wiring board according to one embodiment of the present invention.
FIG. 1 is a plan view of a high-density wiring board viewed from above, and FIG.
(B) is sectional drawing cut | disconnected by the AA shown in FIG. In the present embodiment, a wiring board having a two-layer structure will be described.

As shown in FIG. 1B, the high-density wiring board of this embodiment has a configuration in which an upper wiring board 1 and a lower wiring board 1 'are heat-pressed.

The upper wiring board 1 and the lower wiring board 1 'are each provided with a connection land 2 and a via hole 3 immediately below the connection land 2, and a metal electrically connected to the connection land 2 in the via hole 3. A wire bump 4 is provided.

As shown in FIG. 1, the electrical connection between the upper wiring board 1 and the lower wiring board 1 'is made by connecting the connection lands 2 and the metal wire bumps 4 using the alignment holes 6 provided in each wiring board. Connecting. Further, by providing an interlayer adhesive (insulating adhesive material) 5 between the upper wiring substrate 1 and the lower wiring substrate 1 ', each wiring is insulated and each layer is fixedly connected. The interlayer adhesive 5 uses, for example, an insulating resin such as a polyimide resin or an epoxy resin.

The wiring boards 1, 1 'of each wiring layer shown in FIG.
Examples of the material (insulating film) include, for example, a thermoplastic resin having a heat resistance temperature of 230 ° C. or more, such as a polyimide resin, a liquid crystal polymer, a fluororesin, a polycarbonate resin, an acrylic butadiene styrene resin (ABS), and a polyethylene terephthalate resin (PET). Alternatively, a thermosetting insulating resin film such as a glass fiber-filled epoxy resin may be used.

The above liquid crystal polymer is a main chain type, side chain type, or composite type thermotropic polymer liquid crystal polymer. A polymer having a liquid crystal transition temperature of 200 ° C. or more, or a liquid crystal polymer having a liquid crystal transition temperature of about 120 ° C. It consists of multiple layers coated on a liquid crystal polymer having a transition temperature of 200 ° C. or higher.

The metal wire bumps 4 are made of, for example, a linear conductor such as a gold wire, a gold-plated copper wire, a solder-plated copper wire, or a solder wire, and the conductor is used for interlayer connection using a technique such as wire bonding. It is formed so as to have a projection (stud bump).

The electrical connection between the connection lands 2 of the wiring board of the other layer connected to the metal wire bumps 4 is made by diffusion of metal, solder connection by molten solder wire, diffusion connection by formation of an intermetallic compound, or the like. And so on.

Next, a method for manufacturing the high-density wiring board according to the above-described embodiment will be described.

In the manufacture of the high-density wiring board of this embodiment, as shown in FIG. 2A, first, an insulating resin film 11 with a conductor layer 10 is used, and as shown in FIG. A via hole 3 is formed on the insulating resin surface opposite to the conductor layer 10, and as shown in FIG. 2C, a resist is applied to the conductor layer 10, and exposure, development, etching, and a series of photolithography processes are performed. Then, a wiring pattern 13 is formed. FIG. 1 shows the connection land 2 as a part of the wiring pattern 13.

Thereafter, as shown in FIG. 2D, a metal wire bump 4 is formed on the connection land 2 in the via hole 3. The length of the metal wire bump 4 is
It is formed to be slightly longer than the thickness of.

On the other hand, as shown in FIG. 2E, after the same manufacturing process, another wiring board 1 'is formed by applying an interlayer adhesive 5 on the wiring pattern, and as shown in FIG. 2F. After the plurality of sheets are overlapped and aligned so that the metal wire bumps 4 can be connected to the connection lands 2 on the other layer to which the connection is made, the connection heat is applied by a pressure heating joint method in a connection temperature range of 200 to 350 ° C. By pressing, a multilayer high-density wiring board is formed as shown in FIG.

At the time of this heating and melting, the interlayer adhesive 5 at the connection portion between the projecting portion of the metal wire bump 4 and the connection land 2 is removed by moving so as to fill the via hole 3. Protrusion and connection land 2
Are electrically connected without being insulated.

In particular, in order to prevent thermal damage to the insulating resin film as the wiring board material, a temperature of 230 ° C.
When connecting at the following temperatures, the connection method is selected so that the heat resistant temperature after connection has a heat resistant temperature that can withstand a reflow temperature of 230 ° C. in a solder paste printing reflow method generally used for mounting a semiconductor package. There is a need. For example, a connection method is selected that utilizes the fact that the melting point of the bonding interface becomes higher than the temperature at the time of connection due to the formation of an alloy by metal diffusion.

On the other hand, the adhesive layer also preferably has a viscoelastic coefficient of 1.5 MPa or more at a temperature of 230 ° C. in order to withstand the solder paste printing reflow method at 230 ° C. This is a value experimentally obtained as a viscoelastic coefficient that can withstand the evaporation pressure of moisture contained in the wiring board at a reflow temperature of 230 ° C.

The metal wire bumps 4 are connected to the connection lands 2.
When forming on the connection land 2, or when connecting to the connection land 2 of another layer, a metal part is connected to the connection land 2 side as necessary so that the metal wire bumps 4 can be satisfactorily bonded by ultrasonic wire bonding or the like. May be performed.

By forming the metal wire bumps 4 having a small diameter in the via hole 3, a space for filling the interlayer adhesive 5 in the via hole 3 is formed. Since the agent 5 can be filled into the via hole 3, the wiring density can be increased.

The high-density wiring board may be a memory circuit of an electronic device, such as a RIMM (Rambus Interface Memory Module) shown in FIG.
It is used as a substrate for each circuit such as a control circuit. 3, reference numeral 30 denotes a high-density wiring board of the present embodiment, and 31 denotes a semiconductor package. This makes it possible to further reduce the size of the electronic device.

Next, the case where the metal wire bumps 4 and the connection lands 2 are connected at a low temperature of 230 ° C. or less in the high-density wiring according to the embodiment of the present invention will be specifically described with reference to FIGS. Here, gold wires are used for the metal wire bumps 4, tin-plated copper is used for the connection lands 2, and they are connected at a low temperature by a gold-tin bonding method.

FIG. 4 is an enlarged sectional view for explaining formation of the metal wire bumps 4 and the connection lands 2. FIG.
FIG. 5 is an enlarged cross-sectional view for explaining connection between a formed metal wire bump 4 and a connection land 2.

As shown in FIG. 4, a metal wire bump 4 is formed of a gold wire by a wire bonding method, and a connection land 2 to be connected is tin-plated on a copper wiring by electroplating or electroless tin plating. 7 are formed on the connection land surface and the via hole bottom surface. At this time, a gold wire having a diameter of, for example, about 10 to 50 μm is used.
Has a thickness of about 0.4 to 1.0 μm.

Then, the projections of the gold wires of the metal wire bumps 4 and the tin plating layers of the connection lands 2 were connected at a first eutectic melting point of 217 ° C. (10% by weight of gold-tin alloy) as shown in FIG. I do. At this time, the interface after the connection at the first eutectic melting point by the low-temperature gold-tin bonding method (hereinafter, referred to as a bonding interface) becomes a bonding interface 50 having a heat resistant temperature of 230 ° C. or higher due to the action of the diffusion metal.

This low-temperature gold-tin bonding method is based on Mamorumita, Kum
akura Toyohiko: New Design fora leadframe Used fo
r High-Speed Transmission and High Power LSI packa
ge, IEEE / ECTC Proceeding, P.458, (1992) and Mamoru Mita: Ultra-small multi-pin TAB-BGA for structural reform of LSI package, electronics packaging technology, 11,
(4), page 45, (1995).

FIG. 6 is a diagram showing an equilibrium state of the above-described gold-tin alloy. The equilibrium state in FIG. 6 is shown as a joining temperature ° C at each weight% of gold.

As shown in FIG. 6, the equilibrium state of the gold-tin alloy is 217 ° C. in the composition of 10% by weight of gold-tin alloy.
Has the first eutectic melting point. On the other hand, the conventionally known second eutectic melting point has a composition of about 90% by weight of gold-tin alloy, and this eutectic melting point is as high as about 300 ° C. This second eutectic melting point is a method that has been widely used for sealing semiconductor ceramic packages, but when used for connection of an insulating material of a wiring board made of an organic material, the organic material is thermally degraded. Cannot be adopted.

On the other hand, when the connection is made at the first eutectic melting point, since the heat-resistant temperature of the normal heat-resistant resin is 250 ° C., the insulating resin of the wiring board is not thermally damaged. In this bonding method, the bonding temperature is about 250 ° C., but the bonding interface after bonding has a heat resistant temperature of 300 ° C. This is because gold diffuses into the layer formed at the first eutectic melting point of 217 ° C. in the composition of 10% by weight of gold-tin alloy and further within a short bonding time, or in the case of copper foil wiring, Copper diffuses and the heat-resistant temperature rises.

This is because the strength characteristics of the gold-tin joints of the composite lead frame are as follows: Mamoru Mita, Masaharu Takashiro, Kenji Yamaguchi, Hiroki Tanaka:
Study on connection of LSI lead frame materials (Part 3
Report) Journal of the Japan Welding Society, 15, (1), P.174, (199)
7).

Therefore, the composition of the bonding layer in the low-temperature gold-tin bonding shown in FIG. 5 is such that the bonding interface 50 is composed of 10 to 40% by weight of gold-tin alloy, The extruded fillet portion 51 around the bonding interface is a 5-20% by weight gold-tin alloy.

On the other hand, the formation of the metal wire bumps 4 by wire bonding of a gold wire shown in FIG.
Ultrasonic wire bonding is performed directly on the copper wiring in the via hole 3 (bottom of the via hole) plated with the tin plating 7 having a thickness of 0 μm. The temperature of the wire bonding is from normal temperature to 200 ° C. to prevent oxidation of tin. For this reason, although not shown directly, the bonding interface between the tin plating 7 of the via-hole bottom plating layer and the metal wire bump 4 also becomes gold 10 to 40% by weight-tin alloy from the bonding temperature.

Also, by heating and melting the insulating layer itself or the adhesive layer applied to the insulating layer, the via holes 3 around the metal-bonded projections are filled and sealed as in the case of metal bonding, and finally integrated. Be transformed into At this point, the via hole 3 completely disappears. The metal joining and the insulating resin can be performed almost simultaneously by the same joining machine. The metal bonding between the metal wire bumps 4 and the connection lands 2 and the bonding between the layers and the filling of the via holes by melting at the bonding interface of the insulating resin film or the upper wiring substrate 1 having the insulating resin film coated with the interlayer adhesive 5 are simultaneously performed. Alternatively, the metal bonding may be performed first, or the metal bonding may be performed later.

This is because the metal wire bumps 4 and the connection lands 2 have already been aligned, and even if the insulating resin flows, it cannot enter between the bonding interfaces thereof, or the flowing resin is pressed and pressed to form the metal bonding. Is performed. Therefore, the adhesive layer may be applied so as to fill the via holes of the upper wiring substrate 1, cover the metal wire bumps 4, or cover the entire surface of the lower wiring substrate 1 '.

The above-described electrical connection between the metal wire bumps 4 and the connection lands 2 and the adhesion of the interlayer adhesive 5 can be performed on two or more layers at the same time. FIG. 7 shows an outline of a joining machine used for this connection and bonding.

As shown in FIG. 7, the joining machine comprises a heating tool 19 and a stage 20, between which a plurality of aligned wiring boards 21 are placed. The temperature on the stage side is set to 200 ° C., and the temperature on the heating tool side is set to 250 ° C. Pressurization is in the range of 10 to 50 kgf / cm ² , and an optimum pressure is selected according to the thickness and material of the wiring board.

The bonding time is usually 10 for a two-layer structure.
It takes about 30 seconds for a five-layer structure.

Next, the connection resistance of the metal wire bumps 4 in the high-density wiring board of this embodiment will be described.

FIG. 8 is a diagram showing a method for measuring the connection resistance of the metal wire bumps 4 on the high-density wiring board of the present embodiment.

Although only 12 metal wire bumps 4 are shown in the high-density wiring board of this embodiment shown in FIG. 1A, a plurality of metal wire bumps 4 are further connected in series in an actual wiring board. Is done. Therefore, in the present embodiment, as shown in FIG. 8, the probe 80 is brought into contact with both ends of the metal wire bumps 4 connected in series to
Measure the connection resistance by the terminal method. The conductor resistance up to the probe 80 is canceled in advance by a value obtained by short-circuiting the probe tip.

Therefore, the measured value is the sum of the resistance of the wiring pattern and the resistance of the metal wire bump 4. Since the wiring resistance of the copper wiring is very small, the measured value indicates the connection resistance value of the bump. For example, the reliability test standard for semiconductors (ED4701-B1) specified by the Japan Electronics Machinery Association.
11) Temperature cycle test (-55 ° C / 125 ° C)
, The bump resistance after 1000 cycles is 3 mΩ (milliohm) per bump. This is a connection resistance value that is 1/10 lower than that of a bump made of a normal copper paste.

Therefore, as shown in this embodiment, the use of the metal wire bumps 4 makes it possible to reduce the connection resistance of the bumps on the high-density wiring board.

Further, the diameter of the metal wire bump 4 can be made smaller than that of the bump made of the conductive via paste, so that the via hole can be made smaller and the wiring density can be increased.

An example of a method for manufacturing a high-density wiring board according to the present embodiment of the present invention will be described below.

Example 1 FIG. 9 is a view for explaining a method of manufacturing a high-density wiring board of Example 1.

The method for manufacturing the high-density wiring board according to the first embodiment is as follows.
First, a 70 mm width × 50 μm with a conductor layer 10 made of a high-purity rolled copper foil (99.995% by weight copper) having a thickness of 18 μm.
An insulating resin film 11 made of a thick polyimide tape is prepared for 100 m.

Next, as shown in FIG. 9, first, a wiring 90 and a connection land 2a for forming a wire bump of 0.2 mmφ are formed by photochemical etching.

Subsequently, a via hole 3 having a diameter of 0.1 mm is formed in the land 2a for forming a wire bump on the back surface of the copper foil by using a carbon dioxide gas laser.

Subsequently, electroless tin plating is formed to a thickness of 0.6 μm on the bottom surface side of the via hole of the connection land 2a, the wiring, and the entire surface of the connection land 2a.

Subsequently, a gold metal wire bump 4 is formed using a 35 μmφ gold wire. The height of the gold bump is 60 μm, which is 10 μm higher than the thickness of the polyimide,
The upper wiring board 1 is completed.

Next, another polyimide tape with copper foil is prepared, and a bump connecting land 2b of 0.2 mmφ to which a wire bump is connected is formed by photochemical etching in the same manner. Subsequently, electroless tin plating is formed on the surface of the connection land 2b to a thickness of 0.6 μm to form a lower wiring board. All of the materials used have the same material, thickness and width as those of the upper wiring board 1, and tin plating is applied in the same manner.

Subsequently, the entire surface of the lower wiring board 1 'is coated with an interlayer connecting agent 5 made of a high-purity uncured bisphenol-based epoxy adhesive resin by a roller coating method. The coating thickness is 10 μm.

Thereafter, the two wiring boards thus prepared are aligned using the position holes 6 (not shown), and a two-layer high-density bonding is performed by a low-temperature gold-tin bonding method using a bonding machine shown in FIG. Manufacture a wiring board.

The bonding temperature in the low-temperature gold-tin bonding is 250 ° C.
At this temperature, the uncured bisphenol-based epoxy adhesive resin is in a fluid state, and the gold-tin bonding has already been performed at 217 ° C. In such a case, the metal bonding is performed earlier than the flow of the epoxy adhesive layer of the insulating resin film. After the completion of the gold-tin bonding, the uncured bisphenol-based epoxy adhesive resin flows so as to fill the via holes, and the bonding is completed.

The joining time is 10 seconds (net time of pressurizing and heating by a press). In this joining, the joining machine shown in FIG. 7 was used, but a vacuum press joining machine may be used. In this case, although evacuation time is required, there is an effect that air between the wiring boards is quickly released, and bonding can be performed more reliably. Under these bonding conditions, the semiconductor reliability test standard (ED4
701-B111) (-55 ° C)
/ 125 ° C), the bump resistance after 1000 cycles was 2.8 mΩ per bump.

(Embodiment 2) In Embodiment 1 described above,
The wiring was formed not by lamination of the copper foil but by an electrolytic copper plating method. In this method, first, chromium having a thickness of 30 angstroms is formed on the entire surface of the polyimide by vapor deposition, and a further 5 angstroms having a thickness of 500 angstroms is formed thereon.
After N (99.999%) copper was formed by vapor deposition, copper having a thickness of 18 μm was formed by electroplating.

In this embodiment, a semiconductor reliability test standard (ED4701) specified by the Japan Electronic Machinery Manufacturers Association.
-B111) (-55 ° C / 12
(5 ° C.), the bump resistance after 1000 cycles was 2.3 mΩ per bump. This copper plating material allows the thickness of the copper wiring to be reduced, and is suitable for high-density wiring board applications requiring fine wiring.

Example 3 In Example 1, a liquid crystal polymer was used as the insulating resin film instead of polyimide.
Using. The liquid crystal polymer is a main chain type thermotropic polymer liquid crystal polymer having a liquid crystal transition temperature of 250 ° C. or higher.

Since the liquid crystal polymer 12 can be transferred to liquid crystal at 250 ° C. and flow-bonded, it is a self-adhesive insulating resin film that does not require an adhesive layer. The joining operation was performed at a press temperature of 270 ° C. The joining time is also 10
Seconds. The via hole 3 was completely filled by the flow of the liquid crystal polymer by the bonding. As a result, as shown in FIG. 10, the periphery of the gold wire bump is completely buried with the liquid crystal polymer, and a short circuit between wires due to ion migration when a voltage is applied can be prevented, so that a more reliable wiring board can be obtained. .

(Embodiment 4) In the first embodiment, not only the lower wiring board 1 'but also the upper layer wiring board 1 on the metal wire bump 4 side as shown in FIG. 5 is coated on the entire surface. The other conditions are the same as in the first embodiment. In this case as well, the via hole 3 is completely filled with the adhesive by bonding. This can prevent a short circuit between wirings due to ion migration at the time of applying a voltage.

Example 5 In Example 1, a tin wire was used for the metal wire bump 4 instead of a gold wire. Since the melting point of tin is 232 ° C., the connection temperature was 250 ° C.
This bonding is not a tin-tin bonding but a tin-tin bonding, and the bonding is performed by molten tin. The formation of the wire bump of the tin wire is the same as the gold wire, and is an ultrasonic wire bonder.

In this embodiment, a semiconductor reliability test standard (ED4701) specified by the Japan Electronic Machinery Manufacturers Association.
-B111) (-55 ° C / 12
(5 ° C.), the bump resistance after 1000 cycles was 3.5 mΩ per bump.

(Example 6) In Example 1, the plating of the wiring board was gold plating having a thickness of 0.5 µm. In this configuration, the bonding is performed by diffusion of gold, so the bonding temperature was 250 ° C. and the time was 10 minutes.

(Embodiment 7) In the embodiment 1, in the gold-tin bonding using tin plating, a short circuit between the wirings due to tin plating whiskers may rarely occur. In order to prevent this, the plating on the wiring board side was a 5% by weight lead-tin alloy. Normally, whisker generation in tin plating is prevented by heat treatment after tin plating, plating addition elements, and the like. Use of lead makes it possible to prevent whiskers.

(Embodiment 8) In Embodiment 1, a metal wire bump 4 was used in which a copper wire was plated with gold by 1.0 μm. In this case the purity of the copper wire is important and the purity is 99.999
9% by weight was used. This is because it is known that heavy copper of 5N or more softens and softens at room temperature and can be used as a substitute for a gold wire as a semiconductor bonding wire. This copper wire is produced, for example, by purifying 99.99% by weight of oxygen-free copper by a zone melting method. The connection temperature time is the same as in the first embodiment. The connection resistance after the temperature cycle test was not different from the gold wire.

(Embodiment 9) In Embodiment 1, the diameter of the via hole 3 opened by the carbon dioxide laser was set to 0.07 mm.
φ, and a gold wire having a diameter of 25 μm was used. In this case, the connection land 2 was 0.15 mm. As a result, the wiring density can be improved by 1.5 times as compared with the conventional connection land 2 having a diameter of 0.2 mmφ.

As described above, by using the metal wire bumps 4 instead of the conventional conductive via paste, the connection resistance of the bumps on the high-density wiring board can be reduced.

Further, since the diameter of the metal wire bump 4 can be smaller than that of the conductive via paste, the via hole can be reduced to 0.2 mm or less.
The wiring density can be increased by making it smaller, and the wiring board can be made smaller.

The invention made by the present inventor is described below.
Although specifically described based on the embodiment, the present invention
It is needless to say that the present invention is not limited to the above-described embodiment, but can be variously modified without departing from the scope of the invention.

[0087]

Advantageous effects obtained by typical ones of the inventions disclosed in the present application will be briefly described.
It is as follows.

By using the metal wire bumps 4 instead of the conventional conductive via paste, the connection resistance of the bumps on the high-density wiring board can be reduced.

Further, since the diameter of the metal wire bump 4 can be made smaller than that of the conductive via paste, the via hole can be made 0.2 mm or less.
It is possible to increase the wiring density by reducing the size.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining a configuration of a high-density wiring board according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating a method for manufacturing a high-density wiring board according to the embodiment;

FIG. 3 is a diagram for explaining a configuration of a RIMM.

FIG. 4 is an enlarged cross-sectional view for explaining formation of metal wire bumps 4 and connection lands 2;

FIG. 5 shows formed metal wire bumps 4 and connection lands 2
FIG. 4 is an enlarged cross-sectional view for explaining the connection of FIG.

FIG. 6 is a diagram showing an equilibrium state of gold-tin bonding.

FIG. 7 is a diagram showing an outline of a joining machine.

FIG. 8 is a diagram showing a method for measuring the connection resistance of the metal wire bump 4 in the high-density wiring board of the present embodiment.

FIG. 9 is a diagram for explaining the method for manufacturing the high-density wiring board according to the first embodiment.

FIG. 10 is a diagram for explaining disappearance of via holes when a liquid crystal polymer is used for a wiring board.

FIG. 11 is a view for explaining application of an interlayer adhesive to upper and lower wiring boards.

FIG. 12 is a cross-sectional view illustrating a conventional high-density wiring board.

[Explanation of symbols]

 1, 1 'wiring board 2, 2a, 2b connection land 3 via hole 4 metal wire bump 5 interlayer adhesive 6 alignment hole

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5E317 AA24 BB02 BB03 BB11 BB12 BB13 BB14 BB15 CC08 CC13 CC25 CC31 CD32 GG14 5E346 AA02 AA05 AA12 AA15 AA16 AA22 AA43 BB01 BB15 BB16 BB20 CC04 CC08 CC40 CC33 DD02 EE02 EE41 FF33 FF35 FF36 FF41 GG01 GG15 GG17 GG22 GG28 HH25 HH26

Claims (15)

[Claims] 1. A high-density wiring board having a multi-layer wiring structure in which a plurality of wiring boards are electrically connected to each other to form a single wiring board, and on which a semiconductor device such as a semiconductor package is mounted. The wiring board includes a wiring pattern formed on the insulating film and a connection land electrically connected to another wiring board, and a via hole for connecting to another wiring board is provided directly under the connection land. A high-density wiring board provided on a film, wherein an interlayer connection projection made of a conductor linear projection electrically connecting the connection lands of each of the wiring boards is provided in the via hole. 2. The high-density wiring board according to claim 1, wherein the interlayer connection protrusion is a gold wire, a gold-plated copper wire, or a solder wire formed by wire bonding or the like. High density wiring board. 3. The high-density wiring board according to claim 1, wherein the interlayer connection projections are gold-plated with a diameter of 10 to 50 μm, and the connection lands are tin-plated with a thickness of 0.4 to 1.0 μm. A high-density wiring substrate, wherein the connection between the interlayer connection protrusion and the connection land is made by low-temperature gold-tin connection at a first eutectic point of 217 ° C. 4. The high-density wiring board according to claim 3, wherein the composition of the bonding layer in the connection between the interlayer connection protrusion and the connection land is such that the bonding interface is gold 10-4.
A high-density wiring board comprising: 0% by weight-tin alloy; and a fillet portion around the bonding interface is 5-20% by weight of gold-tin alloy. 5. The high-density wiring board according to claim 1, except for an electrical connection portion between the plurality of wiring boards in the high-density wiring board, which is filled with an insulating adhesive material for insulatingly bonding the wiring boards. A high-density wiring board characterized by being made. 6. The high-density wiring board according to claim 1, wherein said insulating film is made of polyimide resin, liquid crystal polymer, fluororesin, polycarbonate resin, acrylic butadiene styrene resin (ABS), polyethylene terephthalate resin (PET) or the like. A high-density wiring board characterized by being formed of a thermoplastic resin having a heat resistance temperature of 230 ° C. or higher, or a thermosetting resin such as a glass fiber-filled epoxy resin. 7. The high-density wiring board according to claim 6, wherein the liquid crystal polymer has a crystal transition temperature of 200 ° C. or higher and is a main chain type, side chain type or composite type thermotropic polymer liquid crystal polymer. A high-density wiring board, characterized in that it is a multilayer liquid crystal polymer in which a liquid crystal polymer having a liquid crystal transition temperature of about 120 ° C. is coated on a liquid crystal polymer having a liquid crystal transition temperature of 200 ° C. or more. 8. An electronic device formed by mounting a semiconductor device such as a semiconductor package on a wiring board, wherein the wiring board is electrically connected to a wiring pattern formed on an insulating film and another wiring board. A connection land, and a via hole for connection with another wiring board is provided in an insulating film immediately below the connection land, and a linear projection of a conductor electrically connecting the connection land via the via hole is provided. An electronic device, comprising: a high-density wiring board having a multilayer wiring structure in which a plurality of wiring boards are electrically connected to each other to form a single wiring board. 9. A method for manufacturing a high-density wiring board having a multilayer wiring structure in which a plurality of wiring boards are electrically connected to each other to form a single wiring board, and on which a semiconductor device such as a semiconductor package is mounted. 1st joining wiring material to insulating film
And a second step of forming a via hole in the insulating film for connection to another wiring board; and a connection for patterning the wiring material to electrically connect the wiring pattern to another wiring board. A third step of forming a land, a fourth step of forming an interlayer connection projection made of a linear projection of a conductor electrically connected to the connection land in the via hole, and connecting the interlayer connection projection to another. A fifth step of electrically connecting to connection lands of the wiring board, and manufacturing a high-density wiring board having a multilayer wiring structure. 10. The method for manufacturing a high-density wiring board according to claim 9, wherein the fifth step is to connect the interlayer connection projections and the connection lands on a plurality of wiring boards simultaneously by heating and melting. A method for manufacturing a high-density wiring board, comprising: 11. The method of manufacturing a high-density wiring board according to claim 9, wherein the electrical connection of the connection lands in the fourth step and the fifth step is performed by heating and melting the interlayer connection protrusions. A high-density wiring board, the connection being made by diffusion connection, solder connection by molten solder wire, or diffusion connection by formation of a metal compound. 12. The method for manufacturing a high-density wiring board according to claim 9, wherein a gold wire is used for forming the interlayer connection projection and a liquid crystal polymer is used for the insulating film. Before step 4, a metallizing process is performed on the connection land inside the via hole to enable ultrasonic wire bonding, and tin is placed on a connection land of another wiring board to which the other of the interlayer connection protrusions is connected. Plating, tin / lead-based solder plating, or tin / silver-based alloy solder plating, or the like, is performed by metallizing treatment capable of diffusing with gold or by soldering, and using an ultrasonic wire bonder in the fourth step. A protrusion for connecting a gold wire between layers is formed on the connection land inside the via hole, and in the fifth step, the gold wire and the connection land of another wiring board are connected via the via hole. Pressurizing and heating, diffusion of the gold wire and the metal of the connection land subjected to the metallization treatment, electrical connection by heating and melting, melting of the liquid crystal polymer itself, via holes around the more connected gold wire A method for manufacturing a high-density wiring board, characterized by filling the substrate. 13. The method of manufacturing a high-density wiring board according to claim 9, wherein, when the insulating film is made of a material other than a liquid crystal polymer, the wiring pattern of the wiring board to be connected before the fifth step. A step of applying an insulating adhesive material that insulates and bonds between the respective wiring boards on the connection lands and the connection lands, and heating and melting the insulating material together with the interlayer connection protrusions in the fifth step to perform connection. A method for manufacturing a high-density wiring board. 14. The method for manufacturing a high-density wiring board according to claim 13, wherein the heating and melting in the step 5 is performed at 200 ° C. to 350 ° C. so that the melted insulating adhesive material is filled in the via holes. A method for manufacturing a high-density wiring board. 15. The method for manufacturing a high-density wiring board according to claim 13, wherein the connection of the interlayer connection projection, the connection land, and the insulating adhesive material in the step 5 is performed by using the interlayer connection projection and the insulating connection material. The connection of the connection land first,
A method for manufacturing a high-density wiring board, wherein the connection between the interlayer connection protrusion and the connection land is performed later or simultaneously.