JP2005026491A - Method for manufacturing wiring board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a highly reliable and compact wiring board with a projecting bump with a high yield. <P>SOLUTION: A wiring material plate 11 having a copper foil 9 adhered to one main surface and a wiring pattern 8 adhered to the other main surface of an insulator layer 10 with the foil 9 and the pattern 8 electrically connected by a conductor 12 which penetrates through the insulator layer 10 is manufactured. A plating resist layer 12 is provided on the surface of the pattern 8 of the plate 11 by providing an opening part 12a for forming a predetermined connecting bump. A connecting bump 14 is grown at the opening part 12a of the layer 12 by processing an electrolytic plating with the foil 9 of the plate 11 as a power supplying body. A wiring pattern 16 is formed by removing the layer 12 and etching by providing an etching resist layer 15 on the pattern 8 formed surface and the foil 9 surface. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing a wiring board, and more particularly to a method for manufacturing a wiring board with bumps used for mounting.
[0002]
[Prior art]
As electronic devices become shorter, smaller, and thinner, wiring boards that form electrical circuits are required to have high reliability as well as high-density wiring, shorter, smaller, and thinner thicknesses. In response to such demands, multilayer wiring boards have been developed. For example, a multilayer wiring board having a structure in which a polyimide resin or the like is used as an interlayer insulator and a wiring pattern layer is internally provided, while a bump bump for connecting a terminal of an electronic component is formed and provided on the main wiring pattern surface. Is in practical use. In addition, each wiring pattern layer of this multilayer wiring board is electrically connected by a conductor penetrating an interlayer insulator interposed therebetween.
[0003]
And this type of multilayer wiring board is generally manufactured by the following means. First, a copper foil-bonded sheet is prepared by bonding a copper foil to both main surfaces of a polyimide resin film or the like via an adhesive layer. Next, after drilling a predetermined area of this copper foil-bonded sheet and providing via through holes for interlayer connection, the inner wall surface of the through hole is made into a plated conductor, or filled with a conductive composition to connect the interlayer. A conductor is formed and arranged. Thereafter, a photo-etching process is performed on the copper foils on both sides to form a wiring pattern, thereby obtaining a wiring board in which the wiring patterns are connected. And the multilayer wiring board of 3 layers or more is manufactured by repeating the process according to the above (patent document 1).
[0004]
The following configuration is also known as means for simplifying the configuration of the interlayer connection. That is, a protruding conductor (mountain bump) made of a conductive composition, a conductive metal, or the like is formed on a predetermined region surface of the first copper foil. Next, a thermoplastic resin layer and a second copper foil are sequentially laminated and arranged on the forming surface of the protruding conductor of the copper foil. Then, this laminated body was heated and pressurized to be joined and integrated, and a double-sided copper foil bonded plate in which the double-sided copper foil was electrically connected by a protruding conductor having a thermoplastic resin layer inserted therethrough was produced. The double-sided copper foil on the foil-clad plate is etched to form a wiring pattern (Patent Document 1).
[0005]
The manufactured wiring board is used in a mounting circuit device in order to make the electronic circuit compact. For mounting circuit devices, electronic components such as bare chips, BGAs (ball grid arrays), CSPs (chip size packages), and resistor chips are positioned, mounted and arranged on at least one main surface wiring pattern forming surface, Solder must be melted by reflow processing or the like to mount and connect the mounted electronic components. In other words, a bump bump for connection made of nickel or the like is mounted in advance and formed on the wiring pattern surface of the mounting part, corresponding to the terminal bump of the electronic component to be mounted and mounted, and the terminal is connected to this bump bump The bumps are aligned to ensure electrical connection in a state of being separated from each other. On the other hand, in order to reduce the minute stress applied to the connection part between the bumps and protect the mounting electronic component from external humidity and impact, a liquid material called an underfill material is injected and filled between the mounted surfaces. (Patent Document 2).
[0006]
By the way, the formation of the protruding bumps on the wiring board surface is usually performed by the following means. For example, as shown in a plan view in FIG. 2, a wiring pattern 2 forming protruding bumps (connection bumps) 1 a, 1 b, 1 c, 1 d, and 1 e is extended as a power feeding portion 3 to the peripheral portion of the substrate, Electrolytic plating is performed in the order of steps as schematically shown in FIGS. 3A, 3B, 3C, and 3D so that the protruding bumps 1a, 1b, 1c, (1d, 1e are omitted) are formed. Sheng, growing.
[0007]
That is, as shown in a sectional view of the main part in FIG. 3A, a wiring base plate 6 in which wiring patterns 2 connected by conductive bumps 5 penetrating both main surfaces of the insulator layer 4 are disposed. Are prepared, and a plating resist layer 7 is provided on the surfaces where both the wiring patterns 2 are disposed, except for the outside of the line c that is cut and separated in the final outer shape processing. Here, as shown in FIG. 3B, the plating resist layer 7 is selectively opened in the region of the wiring pattern 2 where the bumps 1a, 1b,. (7a) Processed.
[0008]
Next, the wiring base plate 6 provided with the plating resist layer 7 is immersed in an electrolytic nickel plating solution containing nickel sulfate or the like as a main component, and a voltage is applied between the insoluble counter electrode and the power feeding unit 3. As shown in cross section in FIG. 3 (c), nickel-based protruding bumps 1a, 1b,... Are grown and formed. Thereafter, the plating resist layer 7 is removed, and an outer shape process (cutting separation line c) is performed to attach the protruding bumps 1a, 1b,... Shown in FIG. A wiring board is obtained. In addition, as a means for connecting the wiring pattern layers, it is also known that an insulating layer with copper foil is drilled in advance on one side, the copper foil is used as one electroplating electrode, and the inside of the drill is filled with plating metal. Yes.
[0009]
[Patent Document 1]
JP-A-8-264939 (see [0003] [0010])
[0010]
[Patent Document 2]
Japanese Patent Laid-Open No. 11-307586 (see [0002] [0005] [0010] [0014])
[0011]
[Problems to be solved by the invention]
However, the manufacturing process of the wiring board has the following disadvantages. That is, when the bumps 1a, 1b, 1c, and 1d for mounting and mounting the electronic components are built up and grown by electrolytic plating, the power feeding portion 3 corresponding to the same plane is extended. As described above, extending the power feeding portion 3 to the peripheral portion on the same main surface not only complicates the wiring patterning but also restricts the wiring pattern formation region on the main surface, thereby increasing the wiring density. Inhibits compactification.
[0012]
In addition, when the electroplating is advanced by each of the power supply portions 3 corresponding to the protruding bumps 1a, 1b,..., A uniform and uniform voltage is applied to each power supply portion 3 in order to perform uniform electrolytic plating growth. It is also practically difficult to apply, and there is a risk of variations in electrolytic plating. In other words, it is difficult to form the protruding bumps 1a, 1b,... Having a predetermined size and shape as a whole, and there is a concern about a decrease in reliability and the occurrence of defective products, and there are practical problems in terms of yield and productivity. is there.
[0013]
SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a manufacturing method capable of obtaining a highly reliable wiring board with protruding bumps with high yield and high yield.
[0014]
[Means for Solving the Problems]
In the present invention, a copper foil is attached to one main surface of an interlayer insulator layer, a wiring pattern is provided on the other main surface, and the copper foil and the wiring pattern are electrically connected with a conductor penetrating the interlayer insulator layer. Manufacturing a connected wiring base plate;
Providing a plating resist layer by opening a required connection bump forming portion on the wiring pattern surface of the wiring base plate;
A process of subjecting the wiring pattern to electrolytic plating through a conductor penetrating the interlayer insulator layer using the copper foil of the wiring base plate as a common feeding portion, and growing connection bumps in the opening of the plating resist layer; ,
Removing the plating resist layer, providing an etching resist layer on the wiring pattern forming surface and the copper foil surface, etching the copper foil, and patterning the copper foil;
A method for manufacturing a wiring board, comprising:
[0015]
That is, in the invention according to this application, (1) the copper foil on one side of the insulator layer is used as a common power feeding part, and the other side wiring pattern surface connected by the conductive bump penetrating the insulator layer is selected. It is essential to grow bumps by typical electrolytic plating, and (2) after the growth and formation of bumps, patterning the copper foil functioning as a common power feeding portion. By adopting such a configuration, it is possible to easily achieve shortening, lightening and thinning and high-density wiring, and wiring boards with protruding bumps that can reliably achieve reliable mounting and mounting when mounting electronic components. Can be provided in mass production.
[0016]
In the present invention, examples of the interlayer insulator include phenoxy resin, polyether sulfone resin, polysulfone resin, polyphenylene sulfone resin, polyphenylene sulfide resin, polyphenyl ether resin, polyether imide resin, thermoplastic polyimide resin, and liquid crystal polymer. And thermoplastic resins such as polytetrafluoroethylene resin, or thermosetting resins such as epoxy resin, bismaleimide triazine resin, polyimide resin, and polyester resin held in a semi-cured state. This is because the selection of the liquid crystal polymer is particularly suitable for high-frequency transmission and the like because the heat resistance and the stability of the dielectric constant are utilized. The selection of the liquid crystal polymer is advantageous because it has excellent heat resistance, electrical insulation characteristics, dimensional stability, and the like. The liquid crystal polymer is a multiaxially oriented thermoplastic polymer represented by, for example, xidar (trade name, manufactured by Dartco) or Vectra (trade name, manufactured by Clanese). Vectran A type (melting point 285 ° C.), Vectran C type (melting point 325 ° C.), BIAC film (melting point 325 ° C.) and the like are commercially available.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the invention will be described with reference to FIGS. FIG. 1A to FIG. 1G are main-part cross-sectional views schematically showing an embodiment of a method for manufacturing a wiring board with protruding bumps according to an embodiment. First, a copper foil having a thickness of 9 to 35 μm is prepared, and a metal mask having a hole having a diameter of 0.1 to 0.3 mm is positioned and arranged on one main surface side of the copper foil, for example, at a predetermined portion of a stainless steel sheet. Print the conductive paste. After the printed conductive paste is dried, printing is repeated a plurality of times by a method of printing again at the same position using the same metal mask to form a substantially conical or pyramidal chevron bump.
[0018]
Thereafter, a liquid crystal polymer film having a thickness of 25 to 100 μm, for example, a BIAC film having a melting point of 335 ° C. and a copper foil having a thickness of 9 to 35 μm are laminated on the mountain-shaped bump-shaped surface side of the copper foil to form a laminate. . Subsequently, a backing plate is arrange | positioned to both the copper foil surfaces of this laminated body, and it pressurizes and integrates by about 4-8 Mpa as a resin pressure, and manufactures a double-sided copper foil bonding board. In the above pressurization and integration, the chevron bump is inserted through a thermoplastic resin film (interlayer insulator) exhibiting compositional deformability, and its tip reaches the opposing copper foil surface and is crushed. Electrically contact and connect with a resistance of 0.01Ω or less. In addition, the thickness of the thermoplastic resin layer is generally about 25 to 100 μm, although it varies depending on the number of wiring pattern layers to be installed, the thickness of the wiring board, specifications, and the like.
[0019]
The copper foil on one main surface side of the produced double-sided copper foil-clad plate is subjected to photoetching using, for example, an etching solution such as cupric chloride aqueous solution, iron chloride aqueous solution, sulfuric acid-hydrogen peroxide aqueous solution, etc. As shown in (a), a required wiring pattern 8 is formed to produce a copper foil 9-clad plate (wiring base plate) 11 of a single-sided wiring pattern. Here, the wiring pattern 8 is interlayer-connected by a chevron bump 12 that penetrates the thermoplastic resin film 10.
[0020]
Next, as shown in FIG. 1B, a plating resist layer 13 is provided on the wiring pattern 8 forming surface and the copper foil 9 surface of the wiring base plate 11, and a predetermined position of the plating resist layer 13, in other words, Corresponding portions are selectively perforated 13a on the surface of the wiring pattern 8 that requires the formation of the protruding bumps for connection, so that the surface of the wiring pattern 8 is selectively exposed. In other words, as shown in FIG. 1C, the copper foil 9 on the other main surface side is exposed, and the wiring base plate 11 is provided with the plating resist layer 13 on the wiring pattern 8 surface side.
[0021]
Thereafter, for example, the substrate is immersed in a nickel-based electrolytic plating solution to perform required electrolytic plating. Here, the copper foil 9 is used as one electrode, an insoluble electrode (anode) is immersed in the electrolytic plating solution as a counter electrode, and a plating current is supplied from the power source 20. In addition, the plating solution temperature, current density, and the like are appropriately selected according to the shape, size, number, and the like of the bumps 14 that are grown and formed by electroplating.
[0022]
Next, as shown in FIG. 1 (d), after removing the plating resist layer 13, the entire surface from which the plating resist layer 13 has been removed and a common electrolytic plating electrode as shown in FIG. 1 (e). The etching resist 15 is patterned on the surface of the copper foil 9 of the other main surface that functions as the above. Thereafter, a selective etching process using an etching solution is performed, and the copper foil 9 on the other main surface is formed into a wiring pattern 16 as shown in FIG.
[0023]
After the wiring patterning is completed, the etching resist layer 15 is removed to obtain a wiring board with protruding bumps 14 for connection as shown in FIG. 1 (g) with good yield. In addition, after removing the etching resist 15 layer, if necessary, a solder resist process or an outer shape process is performed.
[0024]
In the method of manufacturing the wiring board, the copper foil 9 on the other main surface side is used as a common electrode in forming the connection bump 14 in the electronic component mounting region on one main surface side by electrolytic plating. Then, wiring patterning 16 is performed after the electrolytic plating process. That is, since it is not necessary to pattern a plurality of power supply portions corresponding to the plurality of connection bumps 14 on the plated surface side, it is possible to reduce the complexity of the manufacturing process and eliminate the need for a power supply portion forming surface. Along with this, it is possible to liberalize the wiring pattern and to form a high-density wiring pattern (compact wiring board such as an interposer).
[0025]
In mounting and mounting the mounting electronic component, for example, a BGA type semiconductor device is positioned and arranged. That is, the terminal bumps of the BGA type semiconductor device are positioned and arranged through the solder layer so as to correspond to the protruding bumps 14 of the wiring board, and the semiconductor device is heated to a temperature at which the solder melts in this state, while the semiconductor device is placed on the wiring board side. Mounting is performed by pressure bonding to the substrate. The solder layer may be disposed on at least one of the terminal bump surface of the semiconductor device and the projecting bump surface 14 of the wiring board. Here, the electronic component to be mounted may be a CSP type semiconductor device, a QFP semiconductor device, or a chip resistor instead of the BGA type semiconductor device.
[0026]
The present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the invention. For example, the number of built-in wiring patterns may be a three-layered form or a multilayered form of five or more layers, and the interlayer insulator may be a thermoplastic resin layer, a multilayered thermoplastic resin, a semi-cured thermosetting resin, or A combination of these may also be used.
[0027]
【The invention's effect】
According to the present invention, in forming a bump for connection on the wiring pattern surface of the wiring board on which the mounting electronic component is mounted and mounted by the electrolytic plating process, it is pasted on the other main surface in the state of the wiring base plate. The applied copper foil is used as a common plating electrode. Then, after functioning as a plating electrode, the wiring is panned and used to form a wiring circuit. Therefore, the wiring board surface is used more effectively, and a high-density wiring or a compact wiring board can be easily provided. In addition, when mounting and mounting electronic components, the shape and dimensions of the bumps can be easily controlled. For example, underfill material can be easily injected and filled, and reliable mounting, connection and moisture resistance can be achieved. Etc. can also be given.
[Brief description of the drawings]
FIGS. 1A to 1G are main part cross-sectional views schematically showing a manufacturing mode of a wiring board according to an embodiment in order of processes.
FIG. 2 is a wiring pattern diagram for forming protruding bumps by electrolytic plating in a conventional method for manufacturing a wiring board.
FIGS. 3A to 3D are main part cross-sectional views schematically showing a conventional embodiment of manufacturing a wiring board in the order of steps;
[Explanation of symbols]
8, 16: Wiring pattern 9: Copper foil 10: Insulator layer 11: Wiring base plate 12: Mountain-shaped bump 13: Plating resist layer 13a: Plating resist layer opening 14: Protruding bump (connection bump)
15: Etching resist layer 16: Wiring pattern

Claims (2)

A wiring in which a copper foil is attached to one main surface of an interlayer insulator layer, a wiring pattern is provided on the other main surface, and the copper foil and the wiring pattern are electrically connected by a conductor penetrating the interlayer insulator layer Manufacturing the base plate;
Providing a plating resist layer by opening a required connection bump forming portion on the wiring pattern surface of the wiring base plate;
A process of subjecting the wiring pattern to electrolytic plating through a conductor penetrating the interlayer insulator layer using the copper foil of the wiring base plate as a common feeding portion, and growing connection bumps in the opening of the plating resist layer; ,
Removing the plating resist layer, providing an etching resist layer on the wiring pattern forming surface and the copper foil surface, etching the copper foil, and patterning the copper foil;
A method of manufacturing a wiring board, comprising: 2. The method of manufacturing a wiring board according to claim 1, wherein the interlayer insulator layer is a thermoplastic liquid crystal polymer.

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