JP4491219B2 - Wiring board and manufacturing method thereof - Google Patents

Description

  The present invention relates to a wiring board capable of forming a fine wiring film with high integration and high reliability, and a method for manufacturing the same.

  The applicant company of the present application has developed various techniques for manufacturing a multilayer wiring board, and many of the developed techniques are techniques using metal bumps as interlayer connection means. As a specific example of the technology, an etching barrier layer (thickness, for example, 1 μm) made of nickel, for example, is formed on one main surface of a bump forming copper layer (thickness, for example, 100 μm) by, for example, plating. A wiring circuit board forming member in which a copper foil (thickness, for example, 18 μm) for forming a conductor circuit is formed on the main surface of the etching barrier layer is used as a base, and the surface is finely processed, for example, for interlayer connection by appropriately processing it. A wiring board having bumps which are protrusions is obtained. Regarding this, for example, Japanese Patent Application No. 2000-230142 (Japanese Patent Application Laid-Open No. 2002-43506) and Japanese Patent Application No. 2000-334332 (Japanese Patent Application Laid-Open No. 2002-141629) are obtained. ), And Japanese Patent Application No. 2002-66410 (Japanese Patent Application Laid-Open No. 2002-43506).

Of course, we are also developing other types of wiring boards that utilize such bumps. And, the wiring film of the wiring board, whether utilizing the bumps or not having the bumps, is conventionally a metal layer such as a copper foil on the surface of, for example, an interlayer insulating film and an interlayer connection metal bump. Was formed by a method of patterning by selectively etching the metal layer.
JP 2002-43506 A (Japanese Patent Application No. 2000-230142) JP 2002-141629 A (Japanese Patent Application No. 2000-334332) JP 2002-43506 A (Japanese Patent Application No. 2002-66410)

By the way, according to the above-described conventional technique, there is a problem that it is difficult to form a wiring film more finely and to achieve higher integration while ensuring reliability. That is, with the high integration of ICs, LSIs, etc., with the increasing functionality and miniaturization of various electronic devices using ICs, LSIs, etc., the wiring board is becoming finer and highly integrated. In the conventional technology described above, miniaturization and high integration are approaching the limits.
This is because side etching occurs according to the wiring film forming method of patterning by selectively etching a metal layer such as a copper foil. In particular, it is necessary that the wiring film has no excessive parasitic resistance, and soldering is performed on the surface. However, since the metal constituting the wiring film is partially eaten by the solder, the portion to be eaten is anticipated. Therefore, it is necessary to make the film thicker to a certain extent, and there is a restriction on making it thin because mechanical strength is required to some extent. For this reason, a thickness of at least 5 μm or more is required, but the larger the thickness, the larger the side etching amount. Therefore, the side etching restricts the interval between the wiring films from being narrowed. In turn, this is a major factor that hinders the improvement of the formation density of the wiring film.

In the case of a multilayer wiring board using the metal bump as an interlayer connection means, the metal bump is formed by pressurization and heating for laminating a metal film for wiring film formation on the surface on which the metal bump and the interlayer insulating film are formed. A considerable pressure is applied to the connection portion between the wiring film and the metal film for forming the wiring film, and the pressure causes the underlying side (insulating layer) of the wiring film or the metal film for forming the wiring film to be considerably depressed, and the wiring film or the wiring Since the phenomenon that the metal film for film formation is deformed occurs, the reliability tends to be insufficient.
In addition, when a multilayer wiring technique using bumps as interlayer connection means is applied to a glass substrate as in a liquid crystal device, for example, there is a possibility that the glass substrate may be destroyed by pressurization for lamination. There was also.

  In addition, since the metal bumps shrink due to the pressurization and heating for the above-mentioned lamination, the metal bumps must be formed higher than the final height because of the shrinkage allowance. It is a factor that hinders integration. That is, in the current technology, if the rolling reduction [(bump height before lamination−bump height after lamination) × 100 / bump height before lamination] is not 30% or more, the electrical property between the metal bump and the wiring film The reality is that the necessary reliability of dynamic connectivity cannot be sufficiently secured. By the way, the metal bump is formed by selectively etching a metal layer such as a copper foil for forming the metal bump. Therefore, forming the metal bump higher than the final height is reduced by the amount of side etching. Therefore, the formation of the metal bumps with a high degree of reduction has been a factor limiting the increase in the formation density of the metal bumps.

  The present invention has been made to solve such a problem, and it is possible to further miniaturize the wiring film of the wiring board, regardless of whether it is a type using metal bumps as interlayer connection means. The purpose of this is to achieve high integration with high reliability.

The wiring substrate according to claim 1, wherein a pattern thin film formed in a predetermined pattern by nanometer-scale metal particles or metal oxide particles having an average particle diameter of 1 to 100 nm on at least one surface of the substrate is a base film. And a metal film is plated on the mother film, and a wiring film is formed by the metal plating film and the mother film.
According to a second aspect of the present invention, there is provided a method of manufacturing a wiring board, wherein nanometer-scale metal particles or metal oxide particles having an average particle diameter of 1 to 100 nm are formed in a predetermined pattern on a surface of the substrate on which a wiring film is to be formed. Forming a pattern thin film by the process, fusing the pattern thin film on the underlying surface, plating the metal on the pattern thin film using the pattern thin film as a base film, and the pattern And a plating process for forming a wiring film made of a thin film.

  In the wiring board according to claim 3, a plurality of metal bumps for interlayer connection are selectively formed on the surface of the wiring film or the metal film for forming the wiring film through a thin metal layer made of an etching stop metal layer made of a different material. An interlayer insulating film is formed where the metal bumps on the surface of the wiring film or the metal film for forming the wiring film are not formed, and the wiring film or at least the top surface of the metal bump is in contact with the interlayer insulating film. In a wiring board on which a metal film for forming a wiring film is formed, the connection between the top surface of each metal bump and the surface of the metal film for forming a wiring film is a nanometer-scale metal having an average particle diameter of 1 to 100 nm. It is formed through a thin film made of particles or metal oxide particles.

  According to a fourth aspect of the present invention, there is provided a wiring board manufacturing method comprising a wiring film forming metal film, an etching stop metal layer formed on the surface thereof, and a bump forming metal layer formed on the surface of the etching stop metal layer. A metal plate having a three-layer structure is prepared, and a plurality of metal bumps are formed by selectively etching the bump forming metal film using the etching stop metal layer as an etching stopper, and the etching is performed using the metal bumps as a mask. The stop metal layer is etched, and an interlayer insulating film is formed without covering the top surface of each metal bump where there is no metal bump on the metal bump side surface of the metal plate. A method of manufacturing a wiring board for forming a metal film for forming a wiring film in contact with at least a top surface of the metal bump, wherein the method is in contact with the top surface of the metal bump. Before forming a metal film for forming a wiring film on the top surface of the metal bump, a step of forming a thin film made of nanometer-scale metal particles or metal oxide particles having an average particle diameter of 1 to 100 nm on the top surface of the metal bump. It is characterized by that.

  The wiring board according to claim 5 has metal bumps selectively connected to the surface of the wiring film or the metal film for forming the wiring film on both surfaces of the core board on which the wiring film is formed on both surfaces. A plurality of substrates formed with a plurality of thin metal layers made of an etching stop metal layer and having an interlayer insulating film formed where no metal bumps are formed on the surface of the wiring film or the metal film for wiring film formation Are arranged in a state where the top surfaces of the respective metal bumps are connected to the both-side wiring films of the core substrate, the top surfaces of the respective metal bumps and the surface of the metal film for forming the wiring film. The connection is made through a thin film of nanometer-scale metal particles or metal oxide particles having an average particle diameter of 1 to 100 nm.

  The method for manufacturing a wiring board according to claim 6 is characterized in that metal bumps for interlayer connection are selectively formed on both surfaces of the core board on which wiring films are formed on both sides, on the surface of the wiring film or the metal film for wiring film formation. A plurality of thin metal layers made of etching stop metal layers made of different materials are formed, and an interlayer insulating film is formed where no metal bump is formed on the surface of the wiring film or wiring film forming metal film. In the method of manufacturing a wiring board in which a plurality of substrates are arranged in a state in which the top surfaces of the respective metal bumps are connected to the wiring films on both sides of the core substrate, the top surfaces of the respective metal bumps and the wiring film forming Prior to connection with the surface of the metal film, nanometer-scale metal particles having an average particle diameter of 1 to 100 nm on the top surface of each of the metal bumps or the surface of the metal film for forming the wiring film Metal oxidation It characterized by having a step of forming a thin film by the particles.

  The wiring board according to claim 7 is provided with a liquid crystal display element between a pair of transparent substrates arranged in parallel at a predetermined interval, and the wiring film formed on the surface of one of the transparent substrates A liquid crystal display body portion having a portion extending outside the liquid crystal display element, and the another substrate on which a wiring film is formed on the surface, the liquid crystal display element of the wiring film of the liquid crystal display body portion A wiring board in which a wiring film on the surface of the other substrate is connected to a portion extending outside the wiring board, wherein the wiring film of the liquid crystal display main body portion is separated from a portion extending outside the liquid crystal display element. The connection with the wiring film on the surface of the substrate is made through a thin film made of nanometer-scale metal particles or metal oxide particles having an average particle diameter of 1 to 100 nm.

  The wiring board manufacturing method according to claim 8 is the wiring board manufacturing method according to claim 7, wherein a portion of the wiring film of the liquid crystal display body portion extending outside the liquid crystal display element and a surface of the other substrate are formed. Prior to connection with the wiring film, any of the wiring film of the liquid crystal display main body portion that extends to the outside of the liquid crystal display element and the wiring film on the surface of the other substrate that is connected to each other is connected. On the other hand, the method has a step of forming a thin film of nanometer-scale metal particles or metal oxide particles having an average particle diameter of 1 to 100 nm.

According to the wiring substrate of claim 1, the pattern thin film formed in a predetermined pattern with nanometer-scale metal particles or metal oxide particles having an average particle diameter of 1 to 100 nm is fused as a mother film, Such a base film can be formed by using a very fine and delicate drawing technique by, for example, a so-called ink jet method, dispenser, screen printing, or the like. A wiring film having a necessary thickness can be formed by plating the base film with a metal.
Therefore, a wiring film made of a mother film and a plating film can be formed without side etching, and the wiring film can be miniaturized and highly integrated.

  According to the method for manufacturing a wiring board according to claim 2, a pattern thin film formed in a predetermined pattern is formed with nanometer-scale metal particles or metal oxide particles having an average particle diameter of 1 to 100 nm, and the pattern thin film The pattern thin film is formed by using an extremely fine and delicate drawing technique by an ink jet method, a dispenser or screen printing, etc. Since it is possible to form a wiring film by plating a metal on the base film, it is possible to form a wiring film consisting of a mother film and a plating film without side etching, and to refine the wiring film High integration can be achieved.

According to the wiring substrate of claim 3, the average particle diameter is 1 to 100 nm between the top surface of the metal bump and the wiring film or the wiring film forming metal film electrically connected to the metal bump. Since a thin film made of nanometer-scale metal particles or metal oxide particles is interposed, good electrical connection can be obtained even if the metal bumps and the wiring film or the metal film for forming the wiring film are pressurized and the heating conditions are weakened.
Therefore, since the pressure for laminating the metal film for wiring film formation on the surface on which the metal bump and the interlayer insulating film are formed can be weakened, the metal bump and the wiring film or the metal film for wiring film formation can be reduced. The pressure applied to the connecting portion can be reduced.

Therefore, the underlying side (insulating layer) of the wiring film or the metal film for forming the wiring film is recessed by the pressure for the lamination, and the possibility that the wiring film or the metal film for forming the wiring film is deformed is reduced. Can increase the sex.
Moreover, even if the multilayer wiring technique using bumps as interlayer connection means is applied to a glass substrate such as a liquid crystal device, the glass substrate is not likely to be destroyed by the pressure for lamination. Therefore, the application range of the multilayer wiring technique using bumps as interlayer connection means can be widened.

As described above, even if the applied pressure is lowered, a good electrical connection between the metal bump and the wiring film connected thereto or the metal film for forming the wiring film can be obtained. As a result, the height of the metal bumps selectively formed by etching can be reduced by reducing the reduction allowance, and the side etching amount can be reduced.
Therefore, the metal bumps can be miniaturized and the arrangement density can be increased.

According to the method for manufacturing a wiring board of claim 4, before forming the metal film for forming a wiring film in contact with the top surface of the metal bump, the average particle diameter is 1 to 100 nm on the top surface of the metal bump. Since it has the process of forming the thin film by the nanometer scale metal particle thru | or metal oxide particle, the wiring board of Claim 3 can be obtained.
According to the wiring board of claim 5, in a wiring board of a type in which wiring boards having metal bumps are laminated on both surfaces of the core substrate, nanometer-scale metal particles or metal oxide particles having an average particle diameter of 1 to 100 nm. Therefore, the same effect as that obtained by the wiring board according to claim 3 can be obtained.

According to the method for manufacturing a wiring board of claim 6, prior to the connection between the top surface of each of the metal bumps and the surface of the metal film for forming the wiring film, the top surface of each of the metal bumps and the wiring film forming Since it has the process of forming the thin film by the nanometer scale metal particle thru | or metal oxide particle whose average particle diameter is 1-100 nm in any one of the surface of a metal film, the wiring board of Claim 5 can be obtained. it can.
According to the wiring substrate of claim 7, in the wiring substrate in which the wiring films of the liquid crystal display main body portion and the pair of substrates constituting the wiring substrate are connected to each other, the average particle size is 1 to Since a thin film made of nanometer-scale metal particles or metal oxide particles of 100 nm is interposed, the same effects as those obtained by the wiring board according to claims 3 and 5 can be obtained. The technical effect of the wiring board can be enjoyed by the liquid crystal display device.

  According to the method for manufacturing a wiring board according to claim 8, the wiring film of the liquid crystal display main body portion and the connection between the wiring film of a substrate different from the pair of substrates constituting the liquid crystal display main body portion connected thereto. Prior to the step, a thin film made of nanometer-scale metal particles or metal oxide particles having an average particle diameter of 1 to 100 nm is formed on either the top surface of each metal bump or the surface of the metal film for wiring film formation. Since it has the process of forming, the wiring board of Claim 7 can be obtained.

In summary, in the present invention, it is indispensable to form a thin film made of nanometer-scale metal particles or metal oxide particles. Such a thin film has a very fine metal or metal oxide of nanometer scale. Since it is formed by bonding of product particles, it can be formed finely and can be formed into a fine pattern, which can contribute to the miniaturization and high integration of the wiring film.
In addition, in a thin film made of extremely fine metal or metal oxide particles of nanometer scale, the fine particles are fused and bonded together at a relatively low temperature, so that an infinite number of dense electric currents can be obtained. The conductive path is formed with high density in both the horizontal and vertical directions. Therefore, the electrical conductivity is very good.
Therefore, for example, if it is interposed between a metal bump and a wiring film or a metal film for forming a wiring film, the electrical connectivity between them can be improved, and the pressure and heating conditions required for lamination can be reduced. is there.

In the present invention, it is essential to form a thin film of nanometer-scale metal particles or metal oxide particles having an average particle diameter of 1 to 100 nm. Specific examples of the nanometer-scale particles include gold, Fine particles of at least one kind of metal such as silver, copper, platinum, palladium, rhodium, nickel, etc., fine particles of alloys of two or more kinds of metals, or fine particles of oxides of these metals, such as Ag ₂ O Is mentioned.
These nanometer-scale metal particles are mixed with a water medium or an organic solvent such as xylene, toluene, or olefin, and a dispersant to form an ink (liquid or paste).
Further, particles of metal oxide such as Ag ₂ O are mixed with an alcohol-based solvent such as xylene, toluene or benzene, an olefin-based solvent or a ketone-based solvent, and an amine-based reducing agent, for example. Thus, an ink (liquid or paste) is formed. In order for nanometer-scale particles of metal oxides such as Ag ₂ O to become a wiring film, they are reduced by applied heat and returned to single metal particles or reduced by the action of the applied heat and a reducing agent. This is a case of returning to a single particle, and oxygen is removed at the stage of becoming a wiring film and is no longer a metal oxide.

Metal particles or metal oxide particles mixed with a solvent and a dispersing agent or a reducing agent into an ink form are printed on a substrate by, for example, an ink jet type ink ejection device (kind of ink jet printer), a dispenser, or screen printing. By drawing on the surface of the substrate and other surfaces on which the wiring film is to be formed, a predetermined pattern is formed.
In addition, the manufacturing technique of the wiring board which has the bump of this invention as an interlayer connection means is applicable also to the wiring board which uses a transparent member, for example, a glass plate etc. as a board | substrate. This is because the pressurization and heating conditions necessary for the connection between the bump and the wiring film connected to it can be relaxed by utilizing a thin film made of nanometer-scale metal particles or metal oxide particles. This is because the force applied to the glass substrate is weakened by lowering the applied pressure at the time, and thus the possibility of the breakage can be reduced.

Hereinafter, the present invention will be described in detail according to illustrated embodiments.
1A to 1C are cross-sectional views showing a first embodiment of a method for manufacturing a wiring board according to the present invention in order of steps (A) to (C).
(A) A metal plate 2 is prepared as shown in FIG. The metal plate 2 is made of, for example, copper via an etching stop metal layer 6 made of nickel, for example, on one surface of a wiring film made of copper (or a metal film for forming a wiring film: shown by a two-dot chain line in FIG. 1). The bump 8 is formed, and the top surface of the bump 8 is exposed to the interlayer insulating film 10 made of resin such as epoxy resin on the portion where the bump 8 is not formed on the surface where the bump 8 is formed. It is formed as follows. In the present embodiment, the surface of the interlayer insulating film 10 and the top surface of the bump 8 are formed flat so as to be located on the same plane.

  In addition, the manufacturing method of this metal plate 2 is manufactured by the method described in the section of background art, for example. That is, an etching barrier layer (thickness, for example, 1 μm) made of nickel, for example, is formed on one main surface of a copper layer for bump formation (thickness, for example, 100 μm) by, for example, plating, and further on the main surface of the etching barrier layer. Using a wiring circuit board forming member on which a copper foil (thickness, for example, 18 μm) for forming a conductive circuit is used as a base, by processing it appropriately, bumps that are fine projections for interlayer connection, for example, are formed on the surface Further, it can be obtained by forming an interlayer insulating film. In this regard, for example, Japanese Patent Application No. 2000-230142 (Japanese Patent Application Laid-Open No. 2002-43506), Japanese Patent Application No. 2000-334332 (Japanese Patent Application Laid-Open No. 2002-141629), Japanese Patent Application No. 2002-66410 (: Japanese Patent Application Laid-Open No. 2002-43506). The technical proposal has been made by an application such as No. Gazette) and will not be described in further detail.

(B) Next, as shown in FIG. 1B, nanometer-scale metal particles having an average particle diameter of 1 to 100 nm on the surface of the metal plate 2 on the side where the interlayer insulating film 10 and the bumps 8 are formed. A thin film 12 made of metal oxide particles that is easily reduced by heating is formed into a predetermined pattern by, for example, an ink jet type ink jetting apparatus. The thin film 12 can be formed as thin as, for example, 30 μm or less, and the arrangement density can be made extremely high.
The thin film 12 is formed by ejecting nanometer-scale particles in the form of ink. When the particles are metal particles, the metal particles are water or an alcohol solvent, an aromatic solvent, an olefin solvent or the like. It is mixed with a ketone solvent and a dispersant to form an ink (liquid or paste).

In the case of particles of metal oxide such as Ag ₂ O, for example, alcohol-based, aromatic-based, olefin-based, or ketone-based solvents, and amine-based or amino compounds such as aniline, diphenylamine, phenylamine, It is mixed with a reducing agent such as anilidine to form an ink (liquid or paste).
After the ejection of the thin film 12 by, for example, an ink jet method, the thin film 12 is fused to the base by heat treatment at a temperature of 150 to 250 ° C. At this time, when the particles are metal oxide particles, the particles are reduced to metal particles by this treatment, and the particles are bonded to each other to form an infinite number of conductive paths, and the thin film 12 functions as a wiring film. Make it possible.
Since the formation of the thin film 12 is common to the embodiments described below, detailed description thereof will be omitted and will be omitted.

(C) Next, the surface of the metal plate 2 on the side where the interlayer insulating film 10 and the bumps 8 are formed is immersed in an electroless plating bath to form a plating film 14 on the surface of the thin film 12. Then, the wiring film 16 thickened to a predetermined thickness by plating is obtained. FIG. 1C shows a state in which the wiring film 6 is formed, which corresponds to the first embodiment of the wiring board of the present invention.
Examples of the metal to be electrolessly plated include copper, nickel, silver, gold, and tin.

The significance of the present embodiment will be described. An ink-like material in which nanometer-scale metal particles or metal oxide particles are mixed with a solvent, a dispersant, or a reducing agent is ejected by an ink jet method or the like to form a thin film 12 having a predetermined pattern. However, it is difficult to form a sufficiently thick film or it takes time. However, as in this embodiment, first, the thin film 12 is formed, and then an electroless material such as copper is formed. By plating, the necessary thickness can be secured, the parasitic resistance can be made as small as necessary, and the mechanical strength can be made as strong as necessary. Even if the wiring film made of the thin film 12 is soldered and a part of the metal constituting the thin film 12 is eroded by the solder, the wiring film can be left so that its function can be sufficiently exerted. It is. There is a great significance of this embodiment. Incidentally, if the thin film 12 is too thin, it can happen that it cannot function as a wiring film by being eroded by the solder.
Such a technique for forming a wiring film is not limited to a wiring board using the bumps 8 as interlayer connection means, but can be applied to general wiring boards.

2A and 2B are cross-sectional views showing a second embodiment of the wiring board of the present invention in the order of steps.
(A) A metal plate 2 having the same structure as shown in FIG. 1 (A) is prepared, and the average particle size is 1 on the top surface of the metal bump 8 on the surface on the interlayer insulating film 10 and bump 8 formation side. Ink jetting in which metal particles or metal oxide particles are dispersed in a solvent by a thin film 12 of nanometer scale metal particles or metal oxide particles having a diameter of ˜100 nm, for example, by an ink jet type ink jetting apparatus, and the solvent of the ink thereafter Is formed by drying at a temperature of 150 ° C. or lower.
Thereafter, the metal plate 18 to be laminated is made to face the surface of the metal plate 2 on the side where the interlayer insulating film 10 and the bump 8 are formed. FIG. 2A shows a state where the metal plate 18 is faced.

(B) Next, as shown in FIG. 2B, the metal plate 18 is laminated on the metal plate 2 by pressing and heating. In this case, the heating temperature is, for example, 150 to 250 ° C. At this temperature, the metal particles of the thin film 12 (including those in which the metal oxide particles are converted into metal particles by reduction) are bonded to each other vertically and horizontally. Innumerable fine conductive paths extending in the direction are formed, innumerable conductive paths are also formed in the vertical direction, and are also coupled to the base of the thin film 12. Thereby, the thin film 12 is fused to the base in a state of functioning as a wiring film.
2B corresponds to a second embodiment of the wiring board of the present invention.
Thereafter, the metal layer 4 and the metal plate 18 are selectively made into wiring films by etching.

3A to 3C are cross-sectional views showing a third embodiment of the method for manufacturing a wiring board of the present invention in the order of steps. In the present embodiment, the present invention is applied to a core substrate based on another metal plate laminated on both sides thereof.
(A) As shown in FIG. 3A, a core substrate 30 is prepared, and a thin film 12 made of nanometer-scale metal particles or metal oxide particles is formed on the wiring film 34 by using, for example, an ink jet ink jetting apparatus. The ink is formed by jetting ink in which particles or metal oxide particles are dissolved in a solvent and the like, and then drying at a temperature of 150 ° C. or lower that volatilizes the solvent of the ink.
Reference numeral 32 denotes an insulating base of the core substrate 30, 34 denotes a wiring film formed on both surfaces of the insulating base 32, and 36 denotes an interlayer connection through-hole conductive film formed so as to penetrate the insulating base 32.

(B) Next, as shown in FIG. 3 (B), metal plates 40 and 40 substantially the same as those shown in FIG. 1 (A) are provided on both surfaces of the core substrate 30, and each bump 46 corresponds to it. The core substrate 30 is aligned so that it is aligned with the wiring film 34 of the core substrate 30. Incidentally, 42 is a metal layer, 44 is a metal layer for etching stop made of nickel, 46 is a metal bump, and 48 is an interlayer insulating film (pre-flag).
(C) Next, as shown in FIG. 3C, the metal plates 40 and 40 are laminated on the core substrate 30 by pressing and heating and integrated. The heating temperature is, for example, 150 to 250 ° C. At this temperature, the metal particles of the thin film 12 (including those in which the metal oxide particles are converted into metal particles by reduction) are bonded to each other vertically and horizontally. Innumerable fine conductive paths are formed, and innumerable conductive paths are formed in the vertical direction, and are also coupled to the base of the thin film 12. Thus, the thin film 12 is fused to the base in a state of functioning as a wiring film, which is the same as in the second embodiment.
3C corresponds to a third embodiment of the wiring board of the present invention.

At that time, since such a thin film 38 is formed by bonding of extremely fine metal or metal oxide particles of nanometer scale, it can be formed finely and finely and can be formed in a fine pattern. As a result, it can contribute to the miniaturization and high integration of the wiring film, but not only that, but also the pressure and heating conditions necessary for the lamination can be reduced.
In other words, in a thin film made of extremely fine metal or metal oxide particles on the nanometer scale, an infinite number of dense electrical conduction paths are formed at a high density due to the bonding between the fine particles. The properties are extremely good. Therefore, for example, if it is interposed between a metal bump and a wiring film or a metal film for forming a wiring film, the electrical connectivity between them can be improved, and the pressure and heating conditions required for lamination can be reduced. .

4A and 4B are sectional views showing a fourth embodiment of the method for manufacturing a wiring board of the present invention in the order of steps. In the present embodiment, a technique using a thin film made of nanometer-scale metal particles or metal oxide particles is applied to a wiring board on which chip-shaped electronic components are mounted.
(A) First, a wiring board 50 on which chip-shaped electronic components are mounted is prepared. Then, a thin film 56 made of nanometer-scale metal particles or metal oxide particles is formed on the wiring film 54. FIG. 4A shows a state in which the thin film 56 is formed. Incidentally, 52 is an insulating base of the wiring substrate 50, 54 is a wiring film formed on both surfaces of the insulating base 52, and 56 is a solder resist covering a portion of the surface of the insulating base 52 where the wiring film 54 is not formed.

(B) Thereafter, as shown in FIG. 4B, the electrodes of the electronic components 60 and 60 are connected to the wiring film 54 on which the thin film 56 is formed. As described above, since the thin film 56 is formed by bonding of extremely fine metal or metal oxide particles of nanometer scale, it can be formed finely and precisely. Therefore, the wiring film can be formed in a fine pattern, which can contribute to miniaturization and high integration of the wiring film.

5A and 5B are sectional views showing a fifth embodiment of the method for manufacturing a wiring board of the present invention in the order of steps. In this embodiment, the technique of the first, second or third embodiment is applied to a liquid crystal display device in which a liquid crystal display main body portion and a wiring board are connected thereto.
(A) A liquid crystal display main body portion 70 of the liquid crystal display device and a wiring board 84 connected to the wiring films are prepared.
In FIG. 5, reference numeral 72 denotes one transparent substrate, for example, a glass substrate, and reference numeral 74 denotes a transparent substrate, for example, a glass substrate, which is arranged in parallel with the substrate 72 at a predetermined interval. A liquid crystal 76 is sealed between. Reference numeral 78 denotes a sealing seal. Reference numeral 80 denotes a transparent wiring film made of ITO or the like formed on the surface of the substrate 72. The transparent wiring film 78 is formed of a film of aluminum, chromium, titanium, copper, or the like, has a multilayer structure, and even if the liquid crystal display portion 70 is wired with metal, the occupation ratio is small. A voltage is applied by a transparent electrode at a pixel where there is no pixel.

In the wiring board 84, a wiring film 88 is formed on the surface of the substrate 86, and an electrode of the IC chip 90 is connected to the inner end portion of the wiring film 88 via a solder bump 100, and the IC chip 90 is connected to the wiring board 84. Has been implemented. The mounting may be performed by using an illegal conductive film or by wire bonding without using the solder bump 100.
A thin film 102 made of nanometer-scale metal particles or metal oxide particles is formed on the surface of the outer end portion of the wiring film 88 of the wiring board 84. The method of forming the thin film 102 is the same as that of the thin films 12, 38, and 56. That is, a metal or metal oxide particle is mixed with a solvent or the like to form an ink, and further, a drying process is performed to volatilize the solvent at a temperature of 150 ° C. or lower.
Then, the wiring board 84 is placed on the liquid crystal display body portion 70 so that the outer end portion of the wiring film 88 of the wiring board 84 on which the thin film 102 is formed faces the outer end portion of the wiring film 80 of the liquid crystal display body portion 70. Let us face you. FIG. 5A shows a state in which the wiring board 84 faces the liquid crystal display main body portion 70.

(B) Next, as shown in FIG. 5B, the outer end portion of the wiring film 88 of the wiring board 84 on which the thin film 102 of the wiring board 84 is formed and the outer side of the wiring film 80 of the liquid crystal display main body portion 70. The ends are connected by pressurization and heating (150 to 250 ° C.).
As described above, since the thin film 102 is formed by bonding of extremely fine metal or metal oxide particles of nanometer scale, it can be formed finely and precisely. Therefore, the wiring film can be formed in a fine pattern, which can contribute to miniaturization and high integration of the wiring film.
Therefore, the present invention can be applied to a liquid crystal display device including the liquid crystal display main body portion 70 and the wiring board 84 on which the IC 90 and the like are mounted.

  The present invention can be applied to a wiring board capable of forming a fine wiring film with high integration and high reliability, and a manufacturing method thereof.

(A)-(C) are sectional drawings which show the 1st Example of the manufacturing method of this invention wiring board in order of a process. (A), (B) is sectional drawing which shows the 2nd Example of the manufacturing method of this invention wiring board in order of a process. (A)-(C) are sectional drawings which show the 3rd Example of the manufacturing method of this invention wiring board in order of a process. (A), (B) is sectional drawing which shows the 4th Example of the manufacturing method of this invention wiring board in order of a process. (A), (B) is sectional drawing which shows the 5th Example of the manufacturing method of this invention wiring board in order of a process.

Explanation of symbols

2 ... wiring board, 4 ... metal foil, 6 ... nickel foil, 8 ... metal bump,
10 ... interlayer insulating film,
12: A thin film made of nanometer-scale metal or metal oxide particles,
14 ... Metal plating film, 16 ... Wiring film consisting of thin film and metal plating film,
18 ... Metal plates to be laminated, 30 ... Core substrate, 34 ... Wiring film,
38 ... A thin film made of nanometer-scale metal or metal oxide particles,
40 ... metal plate with metal bumps, 50 ... wiring board, 54 ... wiring film,
56 ... Thin film made of nanometer-scale metal or metal oxide particles,
60: Chip-shaped electronic component. 70 ... Liquid crystal display body part,
72, 74 ... Transparent substrate (glass substrate),
76 ... Liquid crystal, 80, 82 ... Wiring film, 84 ... Wiring board, 86 ... Substrate,
88 ... wiring film, 90 ... IC,
102: A thin film made of nanometer-scale metal or metal oxide particles.

Claims (6)

A plurality of metal bumps for interlayer connection are selectively formed on the surface of the wiring film or wiring film forming metal film via a thin metal layer made of an etching stop metal layer made of a different material, and the wiring film or wiring An interlayer insulating film is formed on the surface of the metal film for film formation where no metal bump is formed, and a wiring film or a metal film for wiring film formation that is in contact with at least the top surface of the metal bump is formed on the interlayer insulating film In the printed wiring board,
The connection between the top surface of each of the metal bumps and the surface of the metal film for forming the wiring film is made through a thin film made of nanometer-scale metal particles or metal oxide particles having an average particle diameter of 1 to 100 nm. A wiring board characterized by: A metal plate having a three-layer structure comprising a metal film for wiring film formation, a metal layer for etching stop formed on the surface thereof, and a metal layer for bump formation formed on the surface of the metal layer for etching stop is prepared. A plurality of metal bumps are formed by selectively etching the bump forming metal film using the metal layer for etching stop as an etching stopper, and the metal layer for etching stop is etched using the metal bump as a mask. An interlayer insulating film is formed in a state where there is no metal bump on the surface of the metal bump side so as not to cover the top surface of each metal bump, and then the wiring film is in contact with at least the top surface of the metal bump on the interlayer insulating film A method of manufacturing a wiring board for forming a forming metal film,
Before forming the metal film for forming a wiring film in contact with the top surface of the metal bump, the top surface of the metal bump is formed of nanometer-scale metal particles or metal oxide particles having an average particle diameter of 1 to 100 nm. A method of manufacturing a wiring board comprising a step of forming a thin film. On both surfaces of the core substrate on which the wiring film is formed on both sides, a metal bump for interlayer connection is selectively formed on the surface of the wiring film or the metal film for forming the wiring film. A plurality of substrates, each having an interlayer insulating film formed on the surface of the wiring film or the metal film for forming a wiring film, where no metal bumps are formed, are formed on the top of each metal bump. In the wiring board arranged in a state where the surface is connected to the wiring films on both sides of the core board,
The connection between the top surface of each of the metal bumps and the surface of the metal film for forming the wiring film is made through a thin film made of nanometer-scale metal particles or metal oxide particles having an average particle diameter of 1 to 100 nm. A wiring board characterized by: On both surfaces of the core substrate on which the wiring film is formed on both sides, a metal bump for interlayer connection is selectively formed on the surface of the wiring film or the metal film for forming the wiring film. A plurality of substrates, each having an interlayer insulating film formed on the surface of the wiring film or the metal film for forming a wiring film, where no metal bumps are formed, are formed on the top of each metal bump. In the method of manufacturing a wiring board arranged with the surface being connected to the wiring films on both sides of the core substrate,
Prior to the connection between the top surface of each metal bump and the surface of the metal film for forming a wiring film, an average particle diameter is applied to either the top surface of each metal bump or the surface of the metal film for forming a wiring film. A method for producing a wiring board, comprising: forming a thin film of nanometer-scale metal particles or metal oxide particles having a thickness of 1 to 100 nm. A liquid crystal display element is provided between a pair of transparent substrates arranged in parallel at a predetermined interval, and a wiring film formed on the surface of one of the transparent substrates extends to the outside of the liquid crystal display element. A liquid crystal display body portion having a portion;
A substrate different from each of the transparent substrates constituting the liquid crystal display main body portion where the wiring film is formed on the surface;
Consists of
A wiring board in which the wiring film on the surface of the other substrate is connected to a portion of the wiring film of the liquid crystal display main body portion that extends to the outside of the liquid crystal display element,
Nanometer-scale metal particles having an average particle diameter of 1 to 100 nm as a connection between a portion of the wiring film of the liquid crystal display body portion extending outside the liquid crystal display element and a wiring film on the surface of the other substrate A wiring board characterized by being made through a thin film of metal oxide particles. A liquid crystal display device having a liquid crystal display element provided between a pair of substrates arranged in parallel at a predetermined interval, and a wiring film formed on the surface of one of the substrates has a portion extending to the outside of the liquid crystal display device A portion extending from the liquid crystal display element of the wiring film of the liquid crystal display main body portion, comprising a display main body portion and a substrate different from the pair of substrates on which a wiring film is formed on the surface In the method of manufacturing a wiring board in which the wiring film on the surface of the other substrate is connected,
Prior to the connection between the portion of the wiring film of the liquid crystal display body portion extending outside the liquid crystal display element and the wiring film on the surface of the other substrate, the liquid crystal display body portion connected to each other. Any one of a portion of the wiring film extending to the outside of the liquid crystal display element and a wiring film on the surface of the other substrate has nanometer-scale metal particles or metal oxidation having an average particle diameter of 1 to 100 nm. A method of manufacturing a wiring board comprising a step of forming a thin film of physical particles.

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