JP5483046B2 - Printed wiring board and manufacturing method thereof - Google Patents

Description

  The present invention relates to a printed wiring board and a manufacturing method thereof. In particular, among printed wiring boards on which electronic component elements and semiconductor elements are mounted, a module substrate on which elements such as electronic component elements and semiconductor elements are once mounted on a printed wiring board at a high density and then mounted on a motherboard. The present invention also relates to a substrate such as a base substrate for a chip electronic component on which an element such as an electronic component element or a semiconductor element is mounted, and a manufacturing method thereof.

Conventionally, a module substrate and a base substrate for chip electronic components use a double-sided copper-clad laminate in which two copper foils are bonded together with an insulating material. For connection to the outside, it is common to provide an end face electrode having a through hole cut in addition to the bottom face electrode.
In addition, in order to manufacture a printed wiring board having an end face electrode particularly when the above-described element is resin-coated, the entrance of the hole is tented so that the coating resin does not flow out of the hole of the through-hole, or, for example, Patent Document As shown in FIG. 1, the through holes were filled with resin.
JP 2002-50714 A

  However, when the through hole is cut to form the end face electrode, the plated film of the through hole is damaged by the cutting blade, or when the plating strength is weak, the end face electrode is peeled off from the printed wiring board during reflow. There's a problem.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a printed wiring board that drastically solves the above problems and that improves the connection strength of the end face electrodes during manufacture and mounting.

In order to solve the above problems, the present invention provides an insulating layer, a copper foil processed into a circuit pattern provided on one side of the insulating layer, and a thickness processed into a circuit pattern provided on the other side of the insulating layer. A copper plate having a thickness of 50 to 500 μm, and an interlayer conductive portion that electrically connects the copper foil and the copper plate through a hole that penetrates the insulating layer and reaches the copper plate, and the interlayer conductive portion is the insulating layer. After filling the hole penetrating with plating or a conductive paste, or providing plating on the wall surface of the hole penetrating the insulating layer, the remaining central portion is filled with a conductive or insulating resin to form a circuit pattern. The end face electrode is divided at the copper plate processed into a copper plate, and the end face of the copper plate is flush with the end face of the insulating layer, and forms an end face electrode that is electrically connected to the copper foil through the interlayer conductive portion. Printed wiring board It is intended to provide.
Further, the present invention provides a printed wiring board in which the interlayer conductive portion is formed by filling a hole that penetrates the copper foil and the subsequent insulating layer and reaches the copper plate.
Further, the present invention provides a printed wiring board in which an interlayer conductive portion is formed by filling a through hole with a hole filling resin after through hole plating.

The printed wiring board of the present invention can provide a printed wiring board with improved connection strength of the end face electrodes at the time of manufacture and mounting.

The copper foil described in the present invention is made of a copper sheet having a thickness of about 1 μm to 20 μm and can be easily deformed. Generally, it consists of copper foil used for the circuit pattern of a printed wiring board. If the thickness is less than 1 μm, handling tends to be difficult, and if the thickness is more than 20 μm, the thickness of the entire printed wiring board increases, and it tends to be unsuitable for high-speed circuits. Also, direct drilling with a laser becomes more difficult.
Further, the copper foil can be replaced with a metal foil made of aluminum, brass, nickel, iron or the like alone, alloy or composite foil. In some cases, a plating or vapor deposition layer of nickel, aluminum, silver, gold or the like is provided on the surface. Further, as long as there is no problem with the adhesion to the base, the copper foil itself may be a plating film or a vapor deposition film.

The copper plate described in the present invention is preferably made of a copper sheet having a thickness of about 50 μm to 500 μm, preferably about 70 μm to 200 μm, and having a large deflection deformation strength. If the thickness is less than 50 μm, the flexural strength of the printed wiring board is reduced and the cross-sectional height of the copper board is reduced, so that the fillet function as an end face electrode of the printed wiring board is likely to be lowered. Also, the heat dissipation characteristics of the printed wiring board are likely to decrease. If the thickness is greater than 500 μm, the thickness and weight of the entire printed wiring board increase and etching processing for electrode formation tends to be difficult.
The copper plate can be replaced with a metal plate made of aluminum, brass, nickel, iron or the like alone, alloy or composite foil. In some cases, a plating or vapor deposition layer of nickel, aluminum, silver, gold or the like is provided on the surface.

The insulating layer described in the present invention is an insulating sheet-like substance, and a resin-impregnated base material that is impregnated with a resin composition in a reinforcing base material such as a prepreg and cured by heating or the like can be used. In particular, when the thickness of the copper plate used in the present invention is relatively thin and easily deforms, it is necessary to reinforce the reinforcing base of the insulating layer and increase the bending strength of the insulating layer.
As the above resin composition, a thermosetting resin having good heat resistance and chemical resistance is usually used as a base, and phenol resin, epoxy resin, polyimide resin, unsaturated polyester resin, polyphenylene oxide resin, fluorine Inorganic powder fillers such as talc, clay, silica, alumina, calcium carbonate, aluminum hydroxide, antimony trioxide, antimony pentoxide, etc. A fiber filler such as glass fiber, asbestos fiber, pulp fiber, synthetic fiber or ceramic fiber is added. In addition, the resin composition may be blended with a thermoplastic resin in consideration of dielectric properties, impact resistance, film processability, and the like. Further, various additives and fillers such as an organic solvent, a flame retardant, a curing agent, a curing accelerator, thermoplastic particles, a colorant, an ultraviolet light impermeant, an antioxidant and a reducing agent are added as necessary.
Examples of the reinforcing substrate include inorganic fibers such as glass and asbestos, polyester, polyamide, polyacryl, polyvinyl alcohol, polyimide, organic fibers such as fluorine resin, natural fibers such as cotton, nonwoven fabric, paper, mats, etc. Is used.
As the adhesive, for example, an epoxy resin, a polyamide resin, a resin-based adhesive such as an acrylic resin or a polyimide resin, an adhesive film, or an adhesive sheet can be used. When the copper plate used in the present invention is thick and strong against deformation, it may be flexible and tough even after curing. The distinction between the adhesive film and the adhesive sheet is the same as the adhesive film, while the thinner one is the adhesive film and the thicker one is the adhesive sheet. In addition to the resin, an insulating inorganic powder filler or fibrous filler may be added as necessary. It is preferable for the dimensional accuracy to add a filler, and the insulating property is also kept good.
The thickness of the adhesive may be about 5 to 20 μm, the thickness of the adhesive film may be about 10 to 50 μm, and the thickness of the adhesive sheet may be about 30 to 500 μm.

  Hereinafter, the present invention will be described based on embodiments shown in the drawings.

FIG. 1 is a schematic sectional view of a printed wiring board according to the present invention.
The printed wiring board of the present invention has a laminated structure in which an insulating layer 3 is provided between a copper foil 1 and a copper plate 2, and the copper foil 1 is processed to form a circuit pattern. 2 is processed to form a circuit pattern.
In other words, a structure of a laminate of a copper foil 1 processed into a circuit pattern provided on one side of the insulating layer 3 and a copper plate 2 processed into a circuit pattern provided on the other side of the insulating layer 3 is taken. Yes.
And the interlayer conduction | electrical_connection part 4 which electrically connected the said copper foil and the said copper plate through the hole which penetrated the insulating layer 3 is provided.
The structure of the interlayer conductive portion 4 is filled with plating or a conductive paste, or after the plating is provided on the hole wall surface, the remaining central portion is filled with a conductive or insulating resin. When there is no copper foil or copper plate at the entrance or exit of the interlayer conductive part 4, when filling with conductive paste or insulating resin, polish it to the same height as the entrance and exit, and apply a plating layer (cover plating) to the surface of the printed wiring board. ) Facilitates subsequent wiring processing and device mounting. Further, when the interlayer conductive portion 4 is formed by filled plating, a plating condition that does not cause a depression on the upper surface of the interlayer conductive portion 4 is selected as much as possible, or if the surface is polished so as to have flatness, Easy wire bonding connection.
The printed wiring board of the present invention is used after mounting an electronic component element, a semiconductor element, or the like, or after coating the element with a resin as necessary. When the cutting is performed at the copper plate 2, the portion can be used as an end face electrode of the printed wiring board.

FIG. 2 shows an example of cutting the printed wiring board of the present invention. FIG. 2A shows a state before cutting, and FIG. 2B shows a state after cutting.
In FIG. 2A, a semiconductor element 5 and a wiring wire 9 extending from the semiconductor element 5 are connected to the copper foil 1 of the printed wiring board of the present invention. The semiconductor element 5 and the wiring wire 9 are sealed. It shows that it is sealed with resin 7. Further, the copper foil 1 is electrically connected to the copper plate 2 on the back surface of the insulating layer 3 through an interlayer conductive portion 4 penetrating the insulating layer 3.
FIG. 2B shows that each printed wiring board with a semiconductor element is cut at the copper plate 2 by a dicing cutter 8 or the like. Since the cut copper board 2 of the printed wiring board with semiconductor elements is thick, it has the function of an end face electrode not only at the bottom face but also at the end face including the cut face.

  FIG. 3 shows an example of a method for producing a printed wiring board according to the present invention. FIG. 3A shows a state before lamination, FIG. 3B shows a case where a through hole 10 is provided, and FIG. 3C shows a case where an interlayer conductive portion 4 is provided in the hole 10 and then FIG. ) Shows a state after the copper foil 1 and the copper plate 2 are processed into a circuit pattern.

FIG. 3A shows a state in which the copper foil 1 and the copper plate 2 are overlapped with each other through an insulating layer 3 of prepreg or adhesive. Lamination is performed in this state. A single-sided copper-clad plate coated with an adhesive can be laminated on the copper plate 2.
FIG. 3B shows a state in which conformal processing is performed in which a window is opened in the copper foil 1 by etching and a hole 10 penetrating the insulating layer is formed by laser processing. In addition, since the heat radiation of the copper plate 2 is better than that of the copper foil 1, it is difficult to perform laser processing. Therefore, depending on the type of the copper foil 1 and the laser processing conditions, the copper plate 1 and the insulating layer 3 that penetrates the copper foil 1 directly by the laser A reaching hole 10 can also be provided. As the laser, CO ₂ and CO, have a solid laser gas laser or a YAG or the like of an excimer like. Since a CO ₂ laser can easily obtain a large output, it is suitable for processing IVH of φ50 μm or more. When processing a fine IVH of φ50 μm or less, a YAG laser with a shorter wavelength and good condensing property is suitable.
FIG. 3C shows a state in which, after the desmear process, the substrate is filled 11, the hole 10 is filled with plating, the interlayer conductive portion 4 is provided, and the copper foil 1 and the copper plate 2 are electrically connected. .
FIG. 3D shows a state after the circuit pattern processing is performed on the metal of the copper foil 1 portion and the metal of the copper plate 2 portion by etching or the like.
Thereafter, an insulating resist, noble metal plating, or the like is provided on the copper foil 1 and the copper plate 2 as necessary to complete the printed wiring board.

  This method is a method in which man-hours are reduced as compared with the following method.

  FIG. 4 shows another example of the method for manufacturing a printed wiring board according to the present invention. 4 (a) shows a state before lamination, FIG. 4 (b) shows a case where the through hole 12 is provided with the interlayer conductive portion 4, and FIG. 4 (c) shows that the through hole 12 is filled. These show the state after processing the circuit pattern of the copper foil 1 and the copper plate 2.

FIG. 4A shows a state in which the copper foil 1 and the copper plate 2 are overlapped with each other through the insulating layer 3 of prepreg or adhesive, as in FIG. Lamination is performed in this state. A single-sided copper-clad plate coated with an adhesive can be laminated on the copper plate 2.
FIG. 4B shows a state in which through-hole plating 13 is performed after the through-hole 12 is provided by a drill or the like. By means of through-hole plating 13, the interlayer conductive portion 4 can be provided in the through-hole 12.
4C, the through hole 12 is filled with a hole filling resin 14 such as an epoxy resin, and the surface of the insulating resin is polished so that the surface of the substrate becomes flat, and then lid plating 15 is provided on both surfaces of the substrate. Indicates the state. The hole filling resin 14 may be a resin alone, a resin mixed with conductive particles, or a resin mixed with palladium active particles for electroless plating.
FIG. 4D shows a state after the circuit pattern processing is performed on the metal of the copper foil 1 part and the metal of the copper plate 2 part by etching or the like.
Thereafter, an insulating resist, noble metal plating, or the like is provided on the copper foil 1 and the copper plate 2 as necessary to complete the printed wiring board.

  In this method, the surface of the upper surface of the interlayer conductive portion 4 is likely to be flat, and the device mounting and wire bonding connection are likely to be facilitated.

  FIG. 5 shows another example of the method for producing a printed wiring board according to the present invention. 5A shows a state after processing the circuit pattern of the copper plate 2, FIG. 5B shows a state after providing the hole 10, and FIG. 5C shows a state after providing the interlayer conductive portion 4. (D) has shown the state after carrying out the circuit pattern process of the copper foil 1 and the copper plate 2. FIG.

FIG. 5A shows a state in which the copper foil 1 and the copper plate 2 having a circuit pattern processed by punching or etching are overlapped with each other through an insulating layer 3 of prepreg or adhesive. Lamination is performed in this state. Moreover, the single-sided copper-clad board which apply | coated the adhesive agent to the copper plate 2 can also be laminated | stacked.
FIG. 5B shows a state in which a window is formed in the copper foil 1 by etching and conformal processing is performed by laser processing to provide a hole 10 that penetrates the insulating layer 3 and reaches the copper plate 2. Moreover, since the heat radiation of the copper plate 2 is better than that of the copper foil 1, the copper plate 2 is harder to be laser-processed than the copper foil 1, so that depending on the type of the copper foil 1 and the conditions of the laser processing, the copper foil 1 is directly followed by laser. A hole 10 penetrating the insulating layer 3 can also be provided.
FIG. 5C shows a state in which the substrate is next subjected to filled plating 11, the hole 10 is filled with plating, the copper foil 1 and the copper plate 2 are electrically connected, and the interlayer conductive portion 4 is provided.
FIG. 5D shows a state after the circuit pattern processing is performed on the metal of the copper foil 1 portion and the metal of the copper plate 2 portion by etching or the like.
Thereafter, an insulating resist, noble metal plating, or the like is provided on the copper foil 1 and the copper plate 2 as necessary to complete the printed wiring board.

In this method, processing that penetrates the thick copper plate is performed with the copper plate alone and then pasted with other members, so that thick copper plates can be used, and the flex strength as a printed wiring board Can be applied with this copper plate. Therefore, the insulating layer can be made thin and the depth of the hole of the filled plating can be made shallow, so that the dent on the upper surface of the hole of the filled plating can be reduced. Moreover, the etching work time after becoming a laminated body can be shortened.

Hereinafter, the present invention will be described based on examples.
First, the copper foil is a copper foil for outer layer wiring having a thickness of 18 μm (Mitsui Metal Mining Co., Ltd., trade name: MT18S5DH).
In addition, a copper plate having a thickness of 105 μm is provided with irregularities having a surface roughness of 3 to 5 μm by CZ treatment (trade name: MEC etch bond CZ-8100, manufactured by MEC Co., Ltd.). . The roughened surfaces were bonded to each other at a temperature of 185 ° C. via a prepreg having a thickness of 70 μm (manufactured by Hitachi Chemical Co., Ltd., trade name: GEA-679FG).
Next, a conformal mask for laser drilling was formed on the copper foil. Next, the CO ₂ laser (manufactured by Hitachi Via Mechanics Co., Ltd., laser processing conditions: frequency 1000 Hz, pulse width 15 μsec, number of cycles 4 times) is irradiated to the conformal mask portion where the copper foil is removed and the resin is exposed. Then, by removing the resin by combustion decomposition, a hole having a diameter of 80 μm that penetrates the copper foil and the subsequent insulating layer and reaches the copper plate was provided.
Next, the desmear treatment in the hole was performed with a permanganate solution.
Next, after applying a catalyst core using a palladium colloid catalyst (made by Hitachi Chemical Co., Ltd., trade name: HS201B) on the metal foil and inside the hole, an electroless plating solution (made by Hitachi Chemical Co., Ltd., trade name) : CUST2000) is used to form a base electroless plating layer having a thickness of 2 μm. Next, an electrolytic plating layer with an electrolytic filled plating solution was formed so that the thickness of the upper surface was 20 μm and the inside of the hole was filled with plating.
Next, the copper layers on both sides were processed into wiring by etching using an etching solution mainly composed of 50 g / l sulfuric acid and 50 g / l hydrogen peroxide. Next, a resist is formed on the surface according to the specifications, and then a nickel plating film with a thickness of 5 μm, a palladium plating film with a thickness of 0.2 μm, and a gold plating film with a thickness of 0.4 μm are sequentially formed on the copper wiring. A printed wiring board was formed.

First, in the same manner as in Example 1, a 18 μm thick copper foil and a 70 μm thick copper foil having a roughened bonding surface were combined with a 70 μm thick prepreg (manufactured by Hitachi Chemical Co., Ltd., trade name: GEA-). 679FG) at a temperature of 185 ° C.
Next, after a through hole having a diameter of 150 μm was provided by a drill, desmear treatment was performed in the same manner as in Example 1, and then through-hole plating was performed. The through-hole plating was 20 μm in electrolytic plating.
Next, a hole filling ink (trade name: IR-10F, manufactured by Yamaei Chemical Co., Ltd.) was filled in the through hole. The ink filling up the surface was dry-cured and then used buffol (# 600, # 800 manufactured by Jablo Industries), and mechanical polishing on the substrate surface was performed at a polishing current of 1.2A. After polishing, copper lid plating was provided. The copper lid plating was electrolytic plating so that the thickness was 12 μm.
Thereafter, as in Example 1, the double-sided copper layer was processed into wiring and precious metal plated to produce a printed wiring board.

First, a wiring pattern was processed by punching a copper plate having a thickness of 175 μm having a roughened bonding surface in the same manner as in Example 1. This copper plate and a 18 μm thick copper foil having a roughened bonding surface were pressure laminated at a temperature of 170 ° C. via a 50 μm thick adhesive sheet (trade name: AD-7006, manufactured by Risho Kogyo Co., Ltd.). . Thereafter, similarly to Example 1, filled plating and double-sided copper layer were processed into wiring and precious metal plating was performed to produce a printed wiring board.

The schematic sectional drawing of the printed wiring board of this invention is shown. The example which cuts the printed wiring board of this invention is shown. The manufacturing method of the printed wiring board of the present invention is shown. The manufacturing method of another printed wiring board of this invention is shown. The manufacturing method of another printed wiring board of this invention is shown.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Copper foil, 2 ... Copper plate, 3 ... Insulating layer, 4 ... Interlayer conduction | electrical_connection part, 5 ... Semiconductor element, 6 ... Wiring wire, 7 ... Sealing resin, 8 ... Dicing cutter, 9 ... Wiring wire, 10 ... Hole, DESCRIPTION OF SYMBOLS 11 ... Filled plating, 12 ... Through-hole, 13 ... Through-hole plating, 14 ... Hole filling resin, 15 ... Lid plating.

Claims (3)

An insulating layer;
Copper foil processed into a circuit pattern provided on one side of this insulating layer,
A copper plate having a thickness of 50 to 500 μm processed into a circuit pattern provided on the other surface of the insulating layer;
An interlayer conductive portion that penetrates the insulating layer and electrically connects the copper foil and the copper plate through a hole reaching the copper plate;
After the interlayer conductive portion fills a hole penetrating the insulating layer with plating or a conductive paste, or after plating is provided on a hole wall surface penetrating the insulating layer, the remaining central portion is made of a conductive or insulating resin. Formed by filling with,
Divided at the copper plate processed into a circuit pattern, the end face by the division of the copper plate is flush with the end face of the insulating layer, and the end face electrode electrically connected to the copper foil through the interlayer conductive portion Printed wiring board to be formed.   The printed wiring board according to claim 1, wherein the interlayer conductive portion is formed by filling a hole reaching the copper plate through the copper foil and the subsequent insulating layer.   3. The printed wiring board according to claim 1, wherein the interlayer conductive portion is formed by filling the through hole with a hole filling resin after performing through hole plating on the through hole.

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