JP4403005B2 - Wiring board and manufacturing method thereof - Google Patents

Description

  The present invention relates to a wiring board, and more particularly to a wiring board using metal bumps as interlayer connection means and a manufacturing method thereof.

For example, Japanese Patent Application No. 11-289277 (Japanese Patent Application Laid-Open No. 2001-111189) and Japanese Patent Application No. 11-289277 disclose a multilayer wiring board using a bump made of a metal such as copper as an interlayer connection means. Various proposals were made by 2003-132793.
In many of the technologies, an etching barrier layer (thickness, for example, 1 μm) made of nickel, for example, is provided on one surface of a metal layer (thickness, for example, 100 μm) made of, for example, copper for forming bumps (protrusions). A metal plate having a three-layer structure in which a metal layer (for example, 18 μm in thickness) made of, for example, copper for forming a wiring film is provided on the surface of the barrier layer (the surface on the side of the anti-bump forming metal layer).

Then, a metal bump is formed by selectively etching the bump-forming metal layer, and then the etching barrier layer is removed using the metal bump as a mask, and then the bump-side surface of the metal plate is formed. The resin film and protective sheet for forming the interlayer insulating film are applied, the resin film and the protective sheet are laminated by pressurization and heating, and then the laminated surface is polished until the top surface of the metal bump is exposed. .
After the polishing, the protective sheet is peeled off, and a metal layer (thickness, for example, 18 μm) made of, for example, copper for forming a wiring film is laminated on the polished surface by pressurizing and heating. The top surface of each metal bump is connected to the metal layer.

Thereafter, the wiring films are formed by selectively etching each wiring film forming metal layer (the wiring film forming metal layer constituting the metal plate having the three-layer structure and the laminated wiring film forming metal layer). Form. As a result, a two-layer wiring board in which interlayer insulation is provided by the resin film and the wiring films are interlayer-connected by metal bumps can be obtained.
This wiring board may be used alone for mounting an IC or the like, or may be stacked with another wiring board to be multilayered and used for mounting an IC or the like.
Japanese Patent Application No. 11-289277 (Japanese Patent Laid-Open No. 2001-111189) Japanese Patent Application No. 2003-132793

However, the conventional technique has a problem that it is difficult to sufficiently increase the reliability of the connection between the metal bump and the metal layer for forming a wiring film in contact with the top surface of the metal bump.
This is because a resin film for forming an interlayer insulation film and a protective sheet are laminated on the surface of the metal bump forming side of the metal plate having a three-layer structure on which the metal bumps are formed, and then the laminated side surface is polished. Because it is necessary to expose the metal bumps by the above, there may be a residue of organic matter on the resin film or protective sheet on the top surface of the metal bumps, so that there is no defect whose connectivity does not satisfy the reliability by the load test Because there is no.

In particular, by polishing, fine scratches (grooves) due to abrasive grains are formed on the top surface of the metal bump, and the resin film or protective sheet residue enters the bottom portion of the scratch and remains on the top surface of the metal bump. This is a factor that deteriorates the reliability of the connection. Such poor bump connectivity may occur at a rate of, for example, 50 bumps per 50 million bumps (50 PPM).
However, in the case where one wiring board unit has, for example, 10,000 bumps, even if there is one metal bump defect in one wiring board, the wiring board becomes defective. The worst unit is 50%. That is, even with a low defect rate of 50 bumps per 1 million bumps, the product yield of the wiring board is very bad at 50% in the worst case. Of course, other defects may also occur, and the overall yield may be lower than 50%. Of course, it is possible to improve by providing a process for removing the residue. Specific examples of the process include plasma cleaning and a desmear process using a strong oxidizing agent. However, these processes adversely affect the insulating resin and are poor in productivity, and are a major cause of hindering cost reduction of products.

Therefore, reducing the connection failure rate of metal bumps is indispensable for improving the yield of the wiring board. However, according to the above prior art, there is a limitation in reducing the connection failure rate of metal bumps. It was difficult to increase the yield of the substrate.
The present invention has been made to solve such problems, and the reliability of the connection between the top surface of the metal bump of the wiring board using the metal bump as an interlayer connection means and the wiring layer connected thereto. The purpose is to increase the yield of the wiring board, and further to improve the connection reliability between the layers, to lower the dielectric constant of the interlayer insulating film, and to improve the electrical characteristics such as high frequency characteristics. To do.

  The wiring board according to claim 1 is composed of one metal layer, and is composed of a wiring film having a metal bump protruding on at least a part of one surface and a metal layer different from the metal layer, at least a part of which is the above A wiring board having at least a wiring film connected to a top surface of a metal bump, wherein the top surface of the metal bump and the wiring film connected to the metal bump are connected by direct metal bonding between metals. Features.

According to a second aspect of the present invention, there is provided a method of manufacturing a wiring board, comprising: preparing one metal layer and another metal layer having a metal bump formed at a predetermined position on one surface; and a top surface of the metal bump; The two metal layers are laminated by connecting one surface of the metal layer by direct metal bonding between the metals, and then a resin is formed between the two metal layers, and then the two metal layers are bonded to each other. A wiring film is formed by selective etching simultaneously or differently.
According to a third aspect of the present invention, there is provided a method for manufacturing a wiring board according to the second aspect, wherein the resin formed between the two metal layers is a foamable resin.

According to a fourth aspect of the present invention, there is provided a method of manufacturing a wiring board, comprising: preparing one metal layer and another metal layer having a metal bump formed at a predetermined position on one surface; and the top surface of the metal bump; The two metal layers are laminated by connecting one surface of the metal layer by direct metal bonding between the metals, and then a resin is formed between the metal layers, and the two metal layers are selected simultaneously or differently. Etching is performed to form a wiring film, and then the resin between the metal layers is removed.
According to a fifth aspect of the present invention, there is provided a core substrate having a wiring film formed on both surfaces of an insulating layer, and having an interlayer connecting portion for connecting the wiring films on both surfaces to the insulating layer, and at least one of each surface of the core substrate. And a metal bump projectingly formed on the surface of the wiring film.

  The method of manufacturing a wiring board according to claim 6 includes: a core substrate having wiring layers formed on both sides of the insulating layer, and having an interlayer connection portion connecting the wiring layers on both sides of the insulating layer; A method of manufacturing a wiring board having a metal bump protrudingly formed on a surface of at least a part of a wiring film, wherein a carrier layer is adhered to one surface of a metal layer for bump formation, and the metal layer is selectively Two bump arrangement bodies in which metal bumps are formed by etching are prepared, and the two bump arrangement bodies are opposed to the surfaces on which the metal bumps are formed on each surface of the core substrate. The top surface of each metal bump and the wiring film on each surface of the core substrate are connected by direct metal bonding between the metals, and then the carrier layer is peeled off and removed. And

  According to a seventh aspect of the present invention, there is provided a wiring board comprising: a wiring film formed on both surfaces of an insulating layer; A wiring board is formed on both surfaces of the base wiring board with the bumps protruding and the insulating layer, and the insulating film has an interlayer connection portion for connecting the wiring films on both surfaces. Two laminated core substrates connected to the wiring film on one side of the base wiring board via the metal bumps and laminated on both surfaces of the base wiring board, and the top surface of the metal bumps, The connection with the wiring film of the laminated core substrate is made by direct metal bonding between metals.

The wiring board according to an eighth aspect is the wiring board according to the seventh aspect, wherein the base wiring board and each of the laminated core boards are insulated by air.
According to a ninth aspect of the present invention, there is provided a core substrate having a wiring film formed on both surfaces of an insulating layer, and having an interlayer connecting portion for connecting the wiring films on both surfaces to the insulating layer, and at least one of each surface of the core substrate. A wiring film connected to the surface of the wiring film through a metal bump projectingly formed, and the top surface of the metal bump and the wiring film are connected by direct metal bonding between the metals. It is characterized by that.

  The wiring board according to claim 10 is provided with two core substrates each having a wiring film formed on both surfaces of the insulating layer and having an interlayer connection portion connecting the wiring films on both surfaces of the insulating layer, and an interlayer connecting metal on the insulating layer. A bump penetrating body in which bumps are penetrated, and between the wiring film on one side of one of the core substrates and the wiring film on one side of the other core substrate, Wiring of the core substrate on the top and bottom surfaces of the metal bump for interlayer connection is made by integrating the two core substrates and the bump penetration body by being connected via the metal bump for interlayer connection of the bump penetration body. The connection with the membrane is characterized by direct metal bonding between metals.

  The method for manufacturing a wiring board according to claim 11 includes: a wiring film formed on both surfaces of the insulating layer; and the insulating layer between two core substrates having an interlayer connection portion connecting the wiring films on both surfaces to the insulating layer. A bump penetrating body in which metal bumps for interlayer connection are penetrated is connected to the wiring film on one surface of one of the core substrates and the wiring film on one surface of the other core substrate. Between the wiring film on one side of one core board and the wiring film on one side of the other core board, the parts to be connected are positioned so as to be connected by the metal bumps for interlayer connection. Are connected by direct metal bonding between the metal via the metal bumps for interlayer connection of the bump penetrating body, and the two core substrates and the bump penetrating body are laminated and integrated. To do.

  The wiring board according to claim 12 is provided with two core substrates each having a wiring film formed on both surfaces of an insulating layer, and having an interlayer connection portion connecting the wiring films on both surfaces of the insulating layer, and an interlayer connecting metal on the insulating layer. A bump penetrating body in which bumps are penetrated is formed between the wiring film on one surface of one of the core substrates and the wiring film on one side of the other core substrate. The body is formed by integrating the two core substrates and the bump penetrating body by being connected via the interlayer connection metal bumps of the body, and another bump is provided on at least one core substrate side of the body. One or a plurality of laminated bodies in which another core substrate is laminated through the penetrating body so that the metal bumps for interlayer connection of the bump penetrating body serve as interlayer connecting means, and the metal bumps of the bump penetrating body are formed. Integrated by connecting the top and bottom surfaces to the wiring film on the core substrate Characterized in that the connection between the top and bottom surfaces and the wiring layer of the core substrate of the interlayer connection metal bumps is being made by direct metal bonding of metal each other.

  The wiring board according to claim 13 is provided with two core substrates each having a wiring film formed on both sides of the insulating layer, and having an interlayer connecting portion connecting the wiring films on both sides of the insulating layer, and an interlayer connecting metal on the insulating layer. A bump penetrating body in which bumps are penetrated is prepared, and the wiring film on one surface of one of the two core substrates is connected to the wiring film on one surface of the other core substrate. Between the ones to be connected by the metal bumps for interlayer connection, the wiring film on one surface of the one core substrate and the wiring film on the other core substrate Are connected by direct metal bonding between the metal via the metal bumps for interlayer connection of the bump penetrating body, so that the two core substrates and the bump penetrating body are integrated, and the integrated The mother body is the one that has become On the other side of the core substrate, another core substrate is connected via another bump penetrating body, and the top and bottom surfaces of the metal bumps for interlayer connection of the bump penetrating body and the wiring film of the core substrate are connected to each other. It is characterized by repeating one or more times to form a layer connecting means by direct metal bonding.

The method for manufacturing a wiring board according to claim 14 is provided on both sides of an insulating layer different from the insulating layer on one or both sides of one bump penetrating body in which an interlayer connecting metal bump is formed through the insulating layer. One or a plurality of pairs of a core substrate having an interlayer connection portion for connecting the wiring films on both sides to the insulating layer and a bump penetrating body different from the bump penetrating body are arranged on the insulating layer. Then, the metal bumps for interlayer connection of the bump penetration bodies and the wiring films of the core substrates to be connected to each other are aligned so that the metal for interlayer connection of the bump penetration bodies is overlaid. By connecting the bumps and the wiring films of each core substrate to be connected to each other by direct metal bonding between the metals, the one bump penetrating body, the core substrate on one side or the therapy side, and another One or more sets of bump penetrations Characterized by the integration of the mating.
A wiring board according to a fifteenth aspect is characterized in that, in the wiring board according to the eighth, ninth, tenth or twelfth aspect, the inner space is sealed by being closed at a peripheral portion.

According to the wiring board of claim 1, the top surface of the metal bump and the wiring film connected to the metal bump are connected by direct metal bonding between the metals, so that the conventional technology as described in the background art section is used. As described in the section of the problem to be solved by the invention, a resin film or a protective film for forming an interlayer insulating film is interposed as a residue between the top surface of the metal bump and the wiring film, and connected. There is no room for the fear that sexual defects will occur.
Therefore, the reliability of the connection between the top surface of the metal bump and the wiring layer connected thereto can be increased, and the yield of the wiring board can be increased.

According to the method for manufacturing a wiring board of claim 2, two metal layers are laminated by connecting a top surface of a metal bump of one metal layer and another metal layer by direct metal bonding between the metals, 2. A wiring board in which a foamable resin is formed between two metal layers, and then the two metal layers are selectively etched simultaneously or differently. Can be obtained.
In addition, since the interlayer insulation is performed with the resin, there is no possibility that foreign matter (dust such as metal powder) enters between the layers, resulting in an insulation failure or a short-circuit failure between the wiring films.
Furthermore, since the resin that insulates the interlayer is a foamable resin and contains a large amount of air, the dielectric constant of the interlayer insulating part is made smaller than that in the case of using an ordinary resin film, and the electronic equipment using the wiring board is used. Parasitic capacitance parasitic on the electronic circuit can be made smaller than before, and circuit characteristics such as high-frequency characteristics can be improved compared to the conventional one.

  According to the method for manufacturing a wiring board of claim 3, two metal layers are laminated by connecting a top surface of a metal bump of one metal layer and another metal layer by direct metal bonding between the metals, Forming a foamable resin between the two metal layers, and then forming the wiring film by selectively etching the two metal layers simultaneously or differently, so that the metal layers are insulated by the foamable resin. The wiring board according to claim 1 can be obtained.

According to the wiring board of claim 4, one metal layer and another metal layer in which metal bumps are formed at predetermined locations on one surface are prepared, the top surface of the metal bumps, and the one metal The two metal layers are laminated by connecting one surface of the layer by direct metal bonding between the metals, and then a resin is formed between the metal layers, and the two metal layers are selectively or simultaneously selected. Etching is performed to form a wiring film, and then the resin between the metal layers is removed, so that the wiring board according to claim 1 in which the layers are insulated by air can be obtained.
According to the wiring board of claim 5, a core substrate having an interlayer connection portion for connecting between the wiring films on both surfaces of the insulating layer having the wiring films formed on both surfaces, and at least a part of each surface of the core substrate. Since it has metal bumps formed on the surface of the wiring film so as to protrude, another wiring board having the metal bump as an interlayer connection means is laminated on each of both surfaces of the core board to form a multilayered wiring board base (starting) Member).

According to the method for manufacturing a wiring board according to claim 6, the top surface of each metal bump and the wiring film on each surface of the core board are connected by direct metal bonding between the metals, and then the carrier layer is peeled off. Therefore, the wiring board according to claim 5 can be obtained.
According to the wiring board of claim 7, since the connection between the top surface of the metal bump of the base wiring board and the wiring film of the two laminated core boards is made by direct metal bonding between the metals, more multilayers are provided. In addition, it is possible to obtain a wiring board having a high yield and a high reliability of interlayer connection.
According to the wiring board of claim 8, in the wiring board of claim 7, since the base wiring board and each of the laminated core boards are insulated by air, the dielectric constant of the interlayer insulating portion is reduced. Thus, the parasitic capacitance parasitic to the electronic circuit of the electronic equipment using the wiring board can be reduced, and the circuit characteristics such as the high frequency characteristics can be improved.

According to the wiring board of claim 9, the wiring board has a wiring film connected via a metal bump projectingly formed on the surface of at least a part of each surface of the core board, and the top surface of the metal bump Since the wiring film is connected to each other by direct metal bonding between the metals, the wiring film is more multilayered with the wiring film connected to the core substrate via the metal bumps on both sides of the core substrate, and the reliability of interlayer connection is increased. A wiring board with high performance and high yield can be obtained.
According to the wiring board of claim 10, the metal bump for interlayer connection in which the wiring film on one surface of one core board and the one wiring film on the other core board are provided through the bump penetration body. The two core substrates and the bump penetrating body are integrated with each other, and the top and bottom surfaces of the interlayer connection metal bumps are connected to the wiring film of the core substrate by direct metal bonding between the metals. Therefore, it is possible to obtain a wiring board having a higher number of layers, a high reliability of interlayer connection, and a high yield.

  According to the method for manufacturing a wiring board according to claim 11, the bump penetrating body is provided between the two core boards, the wiring film on one surface of one of the core boards, and the wiring on one side of the other core board. The layers to be connected to each other are interposed so as to be connected to each other by the metal bumps for interlayer connection, and the wiring film on one surface of one core substrate and the other core substrate The wiring film is connected to one wiring film by direct metal bonding between the metals via the interlayer connection metal bumps of the bump penetrating body, so that the two core substrates and the bump penetrating body are laminated. Since they are integrated, the wiring board according to claim 10 can be obtained.

According to the wiring board of claim 12, the wiring board of claim 10 is used as a base body, and another core board is provided on the side of at least one core board via another bump penetrating body. Since one or more laminated bodies are laminated so that the metal bumps for connection serve as interlayer connection means, the top and bottom surfaces of the metal bumps of the bump penetration body are integrated by connecting the wiring film of the core substrate. Further, it is possible to provide a multilayered wiring board having a larger number of layers than the wiring board according to the tenth aspect.
And, since the connection between the top and bottom surfaces of each of the above-mentioned metal bumps for interlayer connection and the wiring film of each of the core substrates is made by direct metal bonding between the metals, the reliability of the interlayer connection is high and the yield is high. A high wiring board can be obtained.

According to the method for manufacturing a wiring board according to claim 13, after the manufacturing method for the wiring board according to claim 11 is completed, another bump is formed on the side of at least one core substrate of the mother body. Interlayer connection means by connecting another core substrate via the penetrating body, and connecting the top and bottom surfaces of the metal bumps for interlayer connection of the bump penetrating body and the wiring film of the core substrate by direct metal bonding between the metals. Since the stacking is repeated one or more times, the multilayered wiring board according to claim 12 can be provided.
According to the method for manufacturing a wiring board of claim 14, a member necessary for the wiring board of claim 12, that is, a bump penetrating body, and a set of the bump penetrating body and the core substrate on one side or both sides thereof are combined. Alternatively, after preparing and aligning, each metal bump of each bump penetrating body and the wiring film of the core substrate to be connected to each other are connected by direct metal bonding between the metals, and then each member is once Therefore, a multi-layered wiring board having a larger number of layers than the wiring board of claim 10 can be provided with a low number of steps.
According to the wiring board of the fifteenth aspect, it is possible to completely avoid the short circuit, the deterioration of the insulating property, and the possibility of the electric discharge caused by the foreign matter between the layers generated when air is used as the insulating means.

In the present invention, in various types of wiring boards in which interlayer connection is made by metal bumps, the connection between the metal bumps and the wiring film connected to the top surface thereof is made by direct metal bonding between the metals. It is what. The interlayer insulation may be performed with ordinary resin, but the interlayer insulation may be performed with air or a foamable resin containing air.
This is because the dielectric constant of the interlayer insulating portion can be reduced to reduce the parasitic capacitance parasitic to the electronic circuit of the electronic equipment using the wiring board, thereby improving the circuit characteristics and performance. This effect is greater when the interlayer insulation is performed by air than when the interlayer insulation is performed by the foaming resin. However, even if the foaming resin is used, the parasitic capacitance is reduced and the circuit characteristics are reduced. This is because, for example, the high frequency characteristics can be remarkably improved. Further, when a foamable resin containing air is used for interlayer insulation, the resin can also function as a support for the wiring film. However, when the wiring films facing each other are air, that is, when interlayer insulation is performed with air, it can be said that a support for the wiring film needs to be provided outside the wiring film.

  In addition, when the interlayer insulation is made of foaming resin, there is almost no possibility of foreign matter (dust etc.) entering between the layers, but when the interlayer insulation is performed with air, the foreign matter (dust etc.) or moisture between the layers However, there is a slight possibility that it will enter. Therefore, when the interlayer insulation is performed with air as described above, if the peripheral edge portion of each wiring board is closed, the possibility that foreign matter may enter from the outside can be completely eliminated. It is also effective to dispose reinforcing bumps in the periphery or at appropriate locations in order to physically maintain the shape of the wiring films facing each other separately from the metal bumps for interlayer connection.

Hereinafter, the present invention will be described in detail according to illustrated embodiments.
FIGS. 1A to 1D are cross-sectional views showing a method of manufacturing a wiring board according to a first embodiment of the present invention in the order of steps.
(A) First, as shown in FIG. 1A, a metal plate 2 on which metal bumps 8, 8,... Made of copper, for example, and a metal layer 10 for wiring layer formation made of copper, for example, are prepared. Then, the metal layer 10 is made to face the surface of the metal plate 2 on the side where the metal bumps 8 are formed.
In the metal plate 2, a wiring layer forming metal layer 10 is laminated on one surface of a copper layer for forming metal bumps 8, 8,... Via an etching barrier layer 6 forming metal layer made of nickel, for example. Are formed by selective etching of the copper layer for forming the metal bump 8 of the three-layer structure metal plate, and then the metal bump 8, 8,... Is used as a mask. The etching barrier layers 6 are formed by selectively etching the metal layer for forming the etching barrier layer 6 to form the etching barrier layers 6, 6,.

(B) Next, as shown in FIG. 1 (B), the wiring layer is formed on the top surface of each metal bump 8 of the metal plate 2 by using a hot platen and heating and pressing in a vacuum atmosphere using a vacuum press. The metal layer 10 is pressed and the bumps are slightly crushed to directly bond the copper and copper, and the wiring layer forming metal layer 10 is laminated on the metal plate 2.
At the time of lamination, only a small amount of decompressed air is interposed between the wiring layer forming metal layers 4 and 10, and no interlayer insulating resin is interposed.
(C) Next, as shown in FIG. 1C, insulative resin 12 is injected in a state where the outside of the wiring layer forming metal layers 4 and 10 is held by a strong mold.

  Note that epoxy, PPS, urethane, silicone, fluorine, polyimide, or the like can be used as the resin that becomes the interlayer insulating film. However, as the insulating resin, it is simple and optimal to use a self-foaming urethane resin, for example. This is because, compared to the case of using ordinary resin film without foaming, the dielectric constant of the interlayer insulation is made smaller and the parasitic capacitance parasitic to the electronic circuit of the electronic equipment using the wiring board is made smaller than before. This is because the circuit characteristics and performance can be improved as compared with the prior art.

It is easy to fill the urethane resin to every corner of the space between the wiring films together with the curing reaction.
In addition, it can be said that it is preferable to make the bubbles into closed cells having no air permeability because moisture does not penetrate into the wiring board. However, if the peripheral portion of the circuit board is sealed, an open cell structure may be used. In such a case, there is an advantage that a flexible interlayer insulating layer can be obtained.
In addition, the foaming resin is not limited to urethane resin, but thermosetting resin such as epoxy resin kneaded with foaming agent, silicone resin, fluorine resin, unsaturated polyester resin, PEEK resin, PEI resin, PES resin, PPS resin, etc. It is also possible to apply this thermoplastic resin.

(D) Next, as shown in FIG. 1D, wiring films 14, 14,..., 16, 16,... Are formed by selective etching of the wiring layer forming metal layers 4 and 10. To do. Thereby, one wiring board 18 is formed.
In the wiring board 18 shown in FIG. 1 (D), the top surface of the metal bump 8 and the wiring film 10 connected thereto are connected by direct metal bonding between the metals, so as described in the background art section. The problem described in the section of the problem to be solved by the invention that has occurred in the conventional technology, that is, a resin film for forming an interlayer insulating film, a protective film, etc. between the top surface of the metal bump and the wiring film There is no room for the problem of remaining organic matter and the possibility of poor connectivity.
Therefore, the reliability of the connection between the top surface of the metal bump and the wiring layer connected thereto can be increased, and the yield of the wiring board can be increased.

When interlayer insulation is performed by the foamable resin 12, since the resin contains air, the dielectric of the interlayer insulation portion is more than that when a normal resin film having no foam is used as the interlayer insulation means. By reducing the rate, the parasitic capacitance parasitic on the electronic circuit of the wiring board and the electronic equipment using the wiring substrate can be made smaller than before, and the circuit characteristics and performance can be improved than before.
In the first embodiment, after the wiring films 14 and 16 are formed by selective etching of the wiring layer forming metal layers 4 and 10, a coverlay layer that also serves as a support for the wiring film is provided outside. After that, the resin 12 is removed, and layer indirect insulation between the wiring films 14, 14,... And the wiring films 16, 16,. In this case, examples of substances that can withstand the etching solution for the metal film and that are relatively easy to remove include paraffin and polyethylene, and can be melted and removed at a low temperature.

By doing so, since the interlayer insulation is performed by air, the dielectric constant of the interlayer insulation portion is made to be higher than that in the case of using an ordinary resin film as the interlayer insulation means and further in the case of using the foamable resin. The parasitic capacitance parasitic to the electronic circuit of the electronic device using the wiring board can be made smaller than before, and the performance such as circuit characteristics such as high frequency characteristics can be improved compared to the conventional one.
In this case, the low molecular compound or the resin 12 is merely a carrier and is finally removed, so that it is not particularly meaningful to be a foamable resin.

2A to 2D are cross-sectional views showing a method of manufacturing a wiring board according to a second embodiment of the present invention in the order of steps.
(A) As shown in FIG. 2A, a laminate 20 is prepared in which a carrier film 26 made of, for example, resin is bonded to one surface of a bump forming metal layer 22 made of, for example, copper by an adhesive 24.

(B) Next, as shown in FIG. 2B, the bump forming metal layer 22 is selectively etched to form metal bumps 28, 28,. 30 and 30 are bump arrangement bodies on which metal bumps 28, 28,... Are formed.
(C) Next, as shown in FIG. 2 (C), the bump arrangement bodies 30 and 30 shown in FIG. 2 (B) are provided on both sides of the wiring board 18 shown in FIG. 1 (D). The metal bumps 28, 28,... Are arranged one by one in a direction facing the wiring board 18, and the top surfaces of the metal bumps 28, 28,. It is connected to the wiring film of the substrate 18 by direct copper-copper bonding.

(D) Thereafter, as shown in FIG. 2 (D), the carrier film 26 of each bump arranging body 30, 30 is removed. As a result, a wiring substrate 32 in which the top surfaces of the metal bumps 28, 28,... Are connected to the wiring films on both surfaces of the wiring substrate 18 is formed.
This wiring board 32 is used as a core board in the wiring board having a multi-layer structure according to the third embodiment described below.

3A and 3B are cross-sectional views showing a method of manufacturing a wiring board according to a third embodiment of the present invention in the order of steps.
(A) As shown in FIG. 2D, a wiring board 32 as a core board and wiring boards 18 and 18 as double-sided wiring boards laminated thereon are prepared, and the wiring boards are provided on both sides of the wiring board 32. 18 and 18 are positioned and face each other.
(B) Next, as shown in FIG. 3B, the wiring boards 18 and 18 are placed on both sides of the wiring board 32 by reducing the pressure and pressure, and the metal bumps 28, 28,. .. Between the wiring films 14, 14,..., 16, 16,... Of the wiring substrate 32 and the wiring films 14, 14,. The wiring board 32 and the wiring boards 18 and 18 are laminated and integrated by interlayer connection so as to be directly connected by copper-copper bonding. Reference numeral 40 denotes a four-layer wiring board constituted by the integration.

The wiring board 40 shown in FIG. 3B becomes a wiring board that uses air as an insulating means between the wiring board 32 and the double-sided wiring boards 18 and 18 as they are.
In such a wiring board 40, the connection between the metal bumps 28, 28,... And the wiring films 14, 14,. Because it is made by direct copper-copper bonding, a resin film or protective film for forming an interlayer insulating film is interposed as a residue between the metal bump top surface and the wiring film, which has occurred in the prior art, and connectivity There is no room for occurrence of the risk of failure.

Therefore, the reliability of the connection between the top surface of the metal bump and the wiring layer connected thereto can be increased, and the yield of the wiring board can be increased.
In addition, since the wiring board 32 and the wiring boards 18 and 18 are insulated by air, the dielectric constant of the interlayer insulating portion is reduced to reduce the parasitic capacitance that is parasitic on the electronic circuit of electronic equipment using the wiring board. The circuit characteristics and performance can be improved by reducing the size.

FIG. 4 is a cross-sectional view showing a fourth embodiment of the present invention.
In the present embodiment 44, the peripheral portion of the wiring board 40 shown in FIG. 3 is closed with a sealing material 42 made of, for example, resin or the like, and therefore, dust or dirt from the outside is formed between the wiring board 32 and the wiring boards 18 and 18. This prevents foreign matter such as moisture from entering. Further, the closing method can be achieved by a method of pressing the peripheral edge with a mold.
According to such a wiring board 44, it is possible to completely avoid the possibility of a short circuit due to a foreign matter between layers and a decrease in insulation caused when air is used as an insulating means.
As described above, the technique for blocking the peripheral portion of the wiring board with the sealing material 42 made of, for example, resin or the like so that foreign matter such as dust and moisture does not enter from outside is provided between the wiring boards stacked on each other or the wiring board. It can be applied to all types of wiring boards in which the wiring layers are insulated by air.

FIG. 5 is a cross-sectional view showing a fifth embodiment of the present invention.
In the present embodiment 48, an insulating resin is provided between the metal bumps 28, 28,... Of the wiring board 40 forming the core substrate shown in FIG. For example, foamable resin 12 is injected and foamed by means such as heating.
Note that urethane, epoxy, PPS, urethane, silicone, fluorine, polyimide resin, or the like can be used as the resin that becomes the interlayer insulating film. For example, it is easy to form a foamable resin 46 made of urethane. This is the same as in the first embodiment.

6A to 6F are cross-sectional views showing a method of manufacturing a wiring board according to a sixth embodiment of the present invention in the order of steps.
(A) As shown in FIG. 6A, a laminate in which a wiring film forming metal layer 50 made of, for example, copper is bonded to one surface of a bump forming metal layer 22 made of, for example, copper via, for example, an etching barrier layer. A body 60 is prepared.
(B) Next, as shown in FIG. 6B, the bump forming metal layer 50 is selectively etched to form metal bumps 28, 28,. 65 is a bump-disposed metal layer on which metal bumps 28, 28,... Are formed.
(C) Next, as shown in FIG. 6C, the bump-disposed metal layers 65 shown in FIG. 2B are disposed on both sides of the wiring board 18 shown in FIG. Are arranged one by one in the direction facing the wiring board 28 side, and the top surfaces of the respective metal bumps 28, 28... Are directly applied to the wiring films 16, 16,.・ Connect by copper bonding.

(D) Next, paraffin 68 having a melting point of, for example, about 80 ° C. is injected into the space between the bump forming metal layers 50 and 50, and after the paraffin 68 is solidified, as shown in FIG. Wiring films 52, 52,... Are formed by selective etching of the wiring layer forming metal layers 50, 50 of the stacked bodies 60, 60.
(E) Thereafter, as shown in FIG. 6 (E), for example, a polyimide with an adhesive in which both surfaces on which the wiring films 52 and 52 are formed are opened at predetermined positions (72 indicates this opening), for example. The cover lay 70 made of is crimped.
(F) Next, heating is performed as shown in FIG. 6F to dissolve and remove the paraffin, thereby completing the wiring board 80.

FIGS. 7A and 7B are cross-sectional views showing a method of manufacturing a wiring board according to a seventh embodiment of the present invention in the order of steps.
(A) As shown in FIG. 7A, two wiring boards (core boards) 18 and one bump penetrating body 90 shown in FIG. 1D are prepared, and the two wiring boards 18 and 18 are prepared. Are arranged opposite to each other, and a bump penetrating body 90 is interposed between the wiring films 14, 14... On one surface of one wiring substrate 18 and the wiring film 16 on one surface of the other wiring substrate 18. , 16,... Are aligned so that metal bumps 94, 94,.
The bump penetrating body 90 is formed by penetrating metal bumps 94, 94,... In the insulating layer 92, and can be manufactured, for example, by the steps shown in FIGS. This manufacturing method will be described in detail later.

(B) Next, by reducing the pressure and heating, as shown in FIG. 7B, the top surfaces of the respective metal bumps 94, 94... Are turned into the wiring films 14, 14,. The bottom surfaces of the metal bumps 94, 94,... Are connected to the wiring films 16, 16,. The wiring board 96 is completed by laminating and integrating the substrates 18 and 18 and the bump penetrating body 90 interposed therebetween.
In this case, the wiring boards 18 and 18 and the bump penetrating body 90 are insulated by air. In that case, the peripheral edge may be closed as in the fourth embodiment shown in FIG.
As shown in FIG. 8, a resin 98 may be interposed between the wiring boards 18 and 18 and the bump penetrating body 90. A foamable resin may be used as the resin 98. Since these effects have already been described, description thereof will be omitted.

9A and 9B are cross-sectional views showing a method of manufacturing a wiring board according to an eighth embodiment of the present invention in the order of steps. In this embodiment, a wiring board 96 shown in FIG. 7B is used as a base, and wiring boards 18 and 18 as core boards are laminated on both surfaces via bump penetrating bodies 90 and 90, respectively.
(A) One wiring board 96 shown in FIG. 7B, two bump penetrating bodies 90, and two wiring boards 18 shown in FIG. 1D are prepared. The wiring board 18 is arranged opposite to each other through the bump penetrating body 90, and the bumps are provided between the wiring films of the wiring board 96 and the wiring films 14 and 16 of the wiring board 18 to be electrically connected thereto. The wiring board 96, the bump penetrating bodies 90 and 90, and the wiring boards 18 and 18 are aligned so that each metal bump 94 of the penetrating body 90 is located. FIG. 9A shows a state where the alignment is performed.

(B) Next, as shown in FIG. 9B, the wiring films on both surfaces of the wiring board 96 and each bump penetrating body are formed by a hot platen and heating and pressing in a vacuum atmosphere using a vacuum press. The bottom surfaces of the metal bumps 94, 94,... 90, 90, the top surface of the metal bumps 94, and the wiring films 14, 14,. .. Are integrated by pressing the metal bumps 94 by direct metal bonding to each other so that the top and bottom of each metal bump 94 are slightly crushed. A portion formed by the bump penetration body 90 and the wiring board 18 of the integrated wiring board corresponds to a laminated body as defined in claim 12.
In this integration, only a slight amount of decompressed air is present between the top and bottom surfaces of the metal bump 94 and the wiring film, and no interlayer insulating resin is present at all. First to seventh embodiments Is the same as

By the way, the wiring board shown in FIG. 9B has one wiring board 96 as a base, and a set of the bump penetrating body 90 and the wiring board 18 is arranged on each side of the wiring board 96. One set of the bump penetrating body 90 and the wiring board 18 may be disposed only on one side, or a plurality of pairs of the bump penetrating body 90 and the wiring board 18 may be disposed on one side or both sides. Further, it is possible to increase the number of layers.
Then, as shown in FIGS. 9A and 9B, first, one wiring board 96 is formed, and then a set of the bump penetrating body 90 and the wiring board 18 is disposed on each side of the wiring board 96 as a base. However, it may be laminated, but instead, one bump penetrating body 90 and one or a plurality of sets of the bump penetrating body 90 and the wiring substrate 18 disposed on one side or both sides thereof are disposed, The metal bumps 94 and the wiring films may be connected by direct copper / copper bonding between the metals. If it does in this way, it can unify all at once by one process, and can aim at reduction of a man-hour.

In each aspect of the present embodiment, the wiring boards 18 and 18 and the bump penetrating bodies 90 and 90 and the wiring board 96 and the bump penetrating bodies 90 and 90 are insulated by air. Become. In that case, the peripheral edge may be closed as in the fourth embodiment shown in FIG.
Similarly to the wiring board 96 shown in FIG. 8, a resin 98 may be interposed between the wiring boards 18 and 18 and the bump penetration body 90 and between the wiring board 96 and the bump penetration body 90. Alternatively, a foamable resin may be used as the resin 98.

10A to 10E are cross-sectional views showing the method of manufacturing the bump penetrating body 90 in the order of steps.
(A) For manufacturing the bump penetrating body 90, a bump penetrating body manufacturing die 148 shown in FIG. 10A is used. This mold 148 is obtained by fixing a mask film 152 for forming interlayer connection bumps on the surface of a mold substrate 150 having a flat upper main surface, and reference numerals 154, 154,. 94, 94,... Are interlayer connection bump forming holes formed by plating.

The mold substrate 150 is preferably formed of a metal such as stainless steel so that electrolytic plating is possible. When using a metal, the surface chromate treatment (treatment with CrO ₃₎ Then good.
The mask film 152 may be organic or inorganic. However, the processability of forming the mask film with high accuracy, the firm fixability to the mold substrate 150 so that it can be used repeatedly (semi-permanently), and easy wear. It can be said that metal is preferable because it requires hardness that is not broken. And, in order to obtain releasability from copper to be plated, the surface is preferably coated with Teflon (registered trademark) or the like.

(B) Next, as shown in FIG. 10B, interlayer connection bumps 94, 94,... Are formed on the surface of the mold substrate 150 on the side where the mask film 152 is formed by electroplating. In this case, the interlayer connection bumps 94, 94,... Need to be formed so as to protrude from the surface of the mask film 152 to a thickness that is more than the thickness of the interlayer insulating film 92 of the bump penetration body 90. It is.
(C) Next, as shown in FIG. 10 (C), an insulating sheet 156 to be an interlayer insulating film of the bump penetrating body 90 to be formed is made to face the mold substrate 150.
(D) Next, as shown in FIG. 10D, the insulating sheet 122 is laminated on the mold substrate 150 so as to penetrate the interlayer connection bumps 94, 94,. Thereby, the bump penetrating body 90 is formed on the mold 148.

(E) Thereafter, as shown in FIG. 10 (E), the bump penetration body 90 is separated from the mold 148.
According to this example, the mold 148 shown in FIGS. 10A to 10D is repeatedly used for manufacturing the penetrating body 90.
Therefore, according to this example, the bump penetrating body can be easily manufactured sequentially by repeatedly using one of the molds, and the manufacturing cost can be significantly reduced.
In this example, the formed bump penetrating body 90 has a structure in which interlayer connection bumps 94, 94,... Protrude from the lower surface of the interlayer insulating film 92. For example, there may be a flush (flat) aspect or a concave aspect. The bump penetration body and the manufacturing method thereof have been proposed as an interlayer member for manufacturing a multilayer wiring board and a manufacturing method thereof according to Japanese Patent Application No. 2004-93693.
Thus, the present invention can be implemented in various modes.

  The present invention can be applied to a wiring board using metal bumps as interlayer connection means and a manufacturing method thereof in general.

(A)-(D) are sectional drawings which show the manufacturing method of the wiring board which shows the 1st Example of this invention in order of a process. (A)-(D) are sectional drawings which show the manufacturing method of the wiring board which shows the 2nd Example of this invention in order of a process. (A), (B) is sectional drawing which shows the manufacturing method of the wiring board which shows the 3rd Example of this invention in order of a process. It is sectional drawing which shows the 4th Example of this invention. It is sectional drawing which shows the 5th Example of this invention. (A)-(F) is sectional drawing which shows the manufacturing method of the wiring board which shows the 6th Example of this invention in order of a process. (A), (B) is sectional drawing which shows the manufacturing method of the wiring board which shows the 7th Example of this invention in order of a process. It is sectional drawing of the wiring board manufactured by filling resin after completion | finish of the process shown to FIG. 7 (B). (A), (B) is sectional drawing which shows the manufacturing method of the wiring board which shows the 8th Example of this invention in order of a process. (A)-(E) is sectional drawing which shows the manufacturing method of the bump penetration body used in the 7th Example shown in FIG. 7 in order of a process.

Explanation of symbols

2 ... metal plate, 4 ... metal layer for forming a wiring film (copper),
6 ... Etching barrier layer (nickel), 8 ... Metal bump (copper),
10 ... Metal layer for forming a wiring film (copper), 12 ... Interlayer insulating film (foamable resin),
18 ... wiring board (core board), 20 ... member,
22 ... Metal bump forming metal layer, 24 ... Adhesive layer,
26 ... carrier layer (carrier), 28 ... metal bump (copper),
30 ... Bump arrangement body, 32 ... Wiring board, 40 ... Wiring board,
42 ... occlusion material, 44 ... wiring board,
46 ... interlayer insulating film (foamable resin), 65 ... bump-disposed metal layer,
68 ... foaming resin, 70 ... coverlay, 80 ... wiring board,
90 ... Bump penetrating body, 92 ... Insulating layer, 94 ... Metal bump.

Claims (1)

A wiring board is formed on both surfaces of the insulating layer, and a core substrate having an interlayer connection portion for connecting the wiring films on both surfaces to the insulating layer, and a protrusion formed on the surface of at least a part of the wiring film on both surfaces of the core substrate A method of manufacturing a wiring board having a metal bump,
Two bump arrangement bodies in which metal bumps are formed by bonding a carrier layer to one surface of a bump forming metal layer and selectively etching the metal layer,
The two bump arrangement bodies are arranged so that the surfaces on which the metal bumps are formed face each surface of the core substrate,
The top surface of each metal bump and the wiring film on each surface of the core substrate are connected by direct metal bonding between the metals,
Thereafter, the carrier layer is peeled off and removed.

Images