JPH09321435A - Manufacture of multilayer printed-wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To dispense with the work to remove metal pieces at the time when metal films are respectively formed on through holes by a method wherein the upper part of a film body is covered with a masking material in such a way as to mask nuclei for plating adhered to the film body. SOLUTION: An organic substrate 1 formed with conductor circuits 4 is laminated on an electronic component housing hole 2. Then, through holes 3 are formed in places other than the hole 2 provided in a multilayer board 15 constituted integrally by laminating and bonding together the circuits 4. Then, the hole 2 is covered with a film body 8 in such a way that the holes 3 are exposed and nuclei 6 for plating the holes 3 are imparted on the film body 8. Then, the upper part of the film body 8 is covered with a masking material 10 in such a way as to mask these nuclei 6 for plating and a plating is applied to the holes 3 to form respectively metal films 9 on the holes 3. Then, the film body 8 and the material 10, which remain on the board 15, are removed and the hole 2 is made to expose.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pin grid array (PG) for mounting electronic parts such as semiconductor chips.
A), a method of manufacturing a multilayer printed wiring board used for a device for mounting electronic components such as a ball grid array (BGA) and a chip carrier.

[0002]

2. Description of the Related Art In recent years, electronic parts such as semiconductor chips and chip parts have been reduced in size and weight. Along with this, the density of multilayer printed wiring boards for mounting electronic components has been increasing. Conventionally, ceramic substrates were used as substrates on which semiconductor chips were mounted.However, ceramic substrates were expensive, so organic substrates that could be densified and realized at low prices were used. Multilayer printed wiring boards have been used. In addition, the substrate on which the semiconductor chip is mounted is provided with a storage hole for storing the semiconductor chip and a conductor circuit having a gold film on the surface for bonding or connecting (bonding) with the mounted semiconductor chip. General.

A conventional method for manufacturing a multilayer printed wiring board for mounting a semiconductor chip is, for example, Japanese Patent Laid-Open No. 5 (1999) -53187.
There is one shown in -343849. This method
As shown in FIG. 3, a plurality of organic substrates 1 each having a conductor circuit 4 formed thereon are formed with an adhesive material 7 while forming a concave electronic component housing hole 2 in which the conductor circuit 4 is exposed at a predetermined position. 3 (a) !, and then adhered (integrated) to form a multilayer board 15, through holes 3 are formed [FIG. 3 (b)], and then the surface of the multilayer board 15 and electronic parts. A pretreatment for plating is applied to the storage hole 2 and the through hole 3 to form a nucleus 6 for plating [FIG. 3 (c)], and then a dry film is attached as a film body 8 on the entire surface of the multilayer board 15.
The film body 8 (dry film) is exposed and the film body 8 (dry film) in the portion facing the through hole 3 is developed and removed, and the film body 8 (dry film) is left in other portions [FIG. (D)] Next, plating is performed in the through holes 3 to form a metal film 9,
Next, the film body 8 (dry film) is removed, and then the plating nuclei 6 remaining on the surface of the multilayer board 15 and the electronic component housing holes 2 are removed by soft etching [FIG.
(E)] A method for producing a multilayer printed wiring board.

However, in the above method, after removing the film body 8 (dry film) in the step of FIG. 3 (e), the plating nucleus 6 remaining on the surface of the electronic component housing hole 2 is soft-etched. Although it is removed, it is difficult to completely remove it. Therefore, the plating core 6 often remains, and when this core 6 remains, a post-process is performed to form a gold film on the conductor circuit 4 exposed in the electronic component housing hole 2. However, when electrolytic nickel plating or electrolytic gold plating is applied, abnormal deposition of plated metal occurs between the conductor circuits 4 and short circuits often occur.

Therefore, after covering the electronic component accommodating hole with a film body so as to expose the through hole and sealing it,
The present inventors have studied a manufacturing method of solving the above-mentioned problem by providing a through-hole with a nucleus for plating so as not to attach the nucleus for plating to the conductor circuit in the electronic component storage hole, It is proposed as Japanese Patent Application No. 7-334550. In this manufacturing method, as shown in FIG. 4 (a), a plurality of organic substrates 1 are laminated and adhered while forming an electronic component storage hole 2 in which a conductor circuit 4 is exposed at a predetermined position, and are laminated and bonded. 15 and then, as shown in FIG. 4B, a through hole 3 is formed in a portion other than the electronic component accommodating hole 2 of the multilayer board 15, and then the through hole 3 is formed as shown in FIG. 4C.
The electronic component storage hole 2 so that the film body 8 is exposed.
And then through hole 3 as shown in FIG. 4 (d).
The core 6 for plating is applied to, and then the metal film 9 is formed on the through hole 3 by plating as shown in FIG. 4 (e), and then the film body 8 is removed to produce a multilayer printed wiring board. is there. However, in this manufacturing method, since the plating nucleus 6 is attached to the film body 8 at the stage of providing the plating nucleus 6 to the through hole 3 shown in FIG. When the metal film 9 is formed on the through hole 3 by the above, the plated metal piece 11 is deposited on the film body 8 as shown in FIG. 4E, and the removal of the plated metal piece 11 is a troublesome work. It was found that there is a new problem that is required. If the plated metal piece 11 remains, a problem that a desired conductor circuit cannot be obtained and a problem that it becomes difficult to remove the film body 8 in the next step occur.

[0006]

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 plurality of organic substrates forming a conductor circuit with a conductor. While forming the electronic component storage hole where the circuit is exposed at a predetermined position, stacking and adhering to form a multilayer board, then forming a through hole in a portion other than the electronic component storage hole of this multilayer board, and then forming a through hole. After covering the electronic component storage hole with a film body so as to expose it and sealing it, add a nucleus for plating to the through hole, then plate the through hole, then remove the film body, then store the electronic component A method for manufacturing a multilayer printed wiring board, comprising forming a metal layer by electroplating on a conductor circuit in a hole to produce a multilayer printed wiring board, wherein a film is formed when a metal film is formed in a through hole. Plated metal strip does not precipitate on and therefore, is to provide a method for manufacturing a multilayer printed wiring board becomes unnecessary work of removing the plated metal strip.

[0007]

According to a first aspect of the present invention, there is provided a method for manufacturing a multilayer printed wiring board, wherein a plurality of organic substrates, each having a conductor circuit formed therein, are used to store an electronic component in which the conductor circuit is exposed. Layers are laminated and bonded while forming holes at predetermined positions, then through holes are formed in the parts other than the electronic component storage holes of this multilayer plate, and the through holes are plated to form a multilayer printed wiring board. The method for producing a multilayer printed wiring board to be produced is characterized by including the following steps (1) to (6). (1) A step of covering the electronic component accommodating hole with a film body so as to expose the through hole in the multilayer board having the through hole formed (2) Pretreatment of the through hole is performed to form a nucleus for plating Step (3) Step of covering the film body with a masking material so as to mask the nucleus for plating adhered to the film body (4) Step of plating and forming a metal film in the through hole (5) Film The step of removing the body and the masking material (6) The step of forming a metal layer by electrolytic plating on the conductor circuit in the electronic component housing hole. The method for producing a multilayer printed wiring board according to the invention according to claim 2 is the method according to claim 1. In the manufacturing method, the film body is a photosensitive dry film.

According to a third aspect of the present invention, there is provided a method for producing a multilayer printed wiring board according to the first or second aspect, wherein the masking material is a photosensitive dry film.

According to a fourth aspect of the present invention, there is provided a method for producing a multilayer printed wiring board according to the first or second aspect, wherein the masking material is a masking film for plating.

According to a fifth aspect of the present invention, there is provided a method for producing a multilayer printed wiring board according to the first or second aspect, wherein the masking material is a liquid resist.

A method for manufacturing a multilayer printed wiring board according to a sixth aspect of the present invention is the method according to any one of the first to fifth aspects, wherein the plating method in the step (4) is direct plating. It is a law.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described with reference to the drawings.

Step (1) As shown in FIG. 1 (a), a plurality of organic substrates 1 having conductor circuits 4 formed therein are provided with electronic component housing holes 2 in which conductor circuits 4 are exposed at predetermined positions. Laminate while forming. The organic substrate 1 forming the bottom surface 5 of the electronic component storage hole 2 is shown in FIG.
In (a), one having no opening is used, but an opening is formed in the organic substrate 1 forming the bottom surface 5,
An opening may be provided on the bottom surface 5 of the electronic component storage hole 2 when stacked. As the organic substrate 1 forming the conductor circuit 4, an epoxy resin glass cloth base material copper clad laminate, a polyimide resin glass cloth base material copper clad laminate, or the like is used.
An epoxy resin film, a polyimide resin film, an epoxy resin glass cloth base material prepreg, a polyimide resin glass cloth base material prepreg, or the like is used as the adhesive material 7 for laminating the organic base materials 1 and adhering them. Further, in the present invention, a plurality of organic substrates 1 on which the conductor circuits 4 are formed are laminated and adhered, but an organic substrate having no conductor circuits 4 may be laminated simultaneously if necessary.

Next, as shown in FIG. 1 (b), through holes 3 are formed in portions other than the electronic component housing holes 2 of the multilayer board 15 which are laminated, adhered and integrated. The method of forming the through hole 3 is not particularly limited, and can be formed by, for example, drilling. Next, as shown in FIG. 1C, the electronic component housing hole 2 is covered with a film body 8 such as a dry film so that the through hole 3 is exposed with respect to the multilayer plate 15 in which the through hole 3 is formed. When a dry film having photosensitivity is used as the film body 8, it is desirable that the through hole 3 is exposed and the electronic component storage hole 2 can be easily covered with the film body 8. However, polypropylene is used as the film body 8. A general film such as a film may be used without any problem. When a general film is used as the film body 8, for example, one having a predetermined shape in advance is used to expose the through hole 3 and cover the electronic component storage hole 2 by using an adhesive or the like. It may be attached to the plate 15. As the film body 8,
When using a photosensitive dry film, see Fig. 1 (c).
As shown in FIG. 3, the dry film is exposed and developed to remove the dry film in the portion facing the through hole 3 and leave the dry film in the portion covering the electronic component housing hole 2 as it is. As a result, the electronic component storage hole 2 is sealed by the film body 8 (dry film) and is protected from the outside. In this case, the dry film in the portion facing the through hole 3 may be removed, and the dry film in the portion covering the electronic component storage hole 2 may remain, and the dry film in other portions may be used as necessary. You can choose to remove it or leave it. The “portion facing the through hole 3” refers to not only the portion that exactly corresponds to the through hole 3 but also the periphery of the through hole 3 that is a portion that forms a so-called land.

Step (2) As shown in FIG. 1 (d), a plating pretreatment liquid is used to provide a through hole 3 with a conductive material or a nucleus 6 for plating such as palladium. In the case of a so-called direct plating method in which a metal film is formed by direct electrolytic plating without performing electroless plating, a conductive material such as colloidal carbon, organic palladium colloid, or palladium tin alloy colloid is provided as a nucleus 6 for plating. However, in this case, activation treatment may be performed as necessary. When the plating nuclei 6 are provided in the through holes 3 in this way, as shown in FIG. 1D, the plating nuclei are also formed on the surface of the film body 8 which covers the electronic component housing holes 2. 6 is attached.

Regarding Step (3) In this step, as shown in FIG.
To mask the plating nuclei 6 attached to the surface of
The film body 8 is covered with a masking material 10. The material of the masking material 10 is not particularly limited as long as it can withstand the next plating step, and examples thereof include a photosensitive dry film, a plating masking film, and a liquid resist. The method of covering with the masking material 10 is not particularly limited, and may be determined according to the type of the selected masking material 10. The multilayer plate 15 may be thinly plated before the film body 8 is covered with the masking material 10. Because, in the present invention, the film body 8 and the masking material 10 are removed in a later step, but the removal of the film body 8 and the masking material 10 is not difficult if the metal film is formed by thin plating and has a thickness of several μm or less. Because. By performing the step (3), the plating nucleus 6 on the film body 8 is covered with the masking material 10 and is not exposed on the surface of the film body 8.

Step (4) In this step, as shown in FIG. 2 (f), the through hole 3 is plated to form a metal film 9. The plating method at this time is not particularly limited, and, for example, a method of forming a metal film having a desired film thickness by electrolytic plating after performing thin plating by electroless plating or forming the metal film 9 by direct electrolytic plating. The so-called direct plating method may be used. The material of the metal film 9 is also not particularly limited, and examples thereof include copper, nickel, gold and the like.

Step (5) In this step, the film body 8 and the masking material 10 remaining on the multilayer board 15 after the above step (4) are removed, and as shown in FIG. The electronic component storage hole 2 is exposed. Note that, along with the removal of the film body 8 and the masking material 10, the plating core 6 attached to the surface of the film body 8 is also removed. The method of removing the film body 8 and the masking material 10 is not particularly limited and may be a method suitable for the material used. For example, in the case of an alkali peeling type dry film, it can be peeled using an alkaline solution.

Step (6): A metal layer is formed by electrolytic plating on the conductor circuit 4 exposed in the electronic component housing hole 2 (not shown). The material of the metal layer is not particularly limited, but copper, nickel, gold and the like can be exemplified, and finally it is preferable to provide a metal layer of gold on the surface from the viewpoint of bonding property. It is also possible to first form a base metal layer of nickel or the like by electrolytic plating, and then form a gold metal layer thereon by electrolytic plating.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described based on embodiments with reference to the drawings.

A polyimide resin glass cloth base material prepreg used as the adhesive material 7 and three organic substrates 1 having conductor circuits 4 formed on a polyimide resin glass cloth base material copper clad laminate were prepared. The organic substrate 1 and the adhesive material 7 excluding the organic substrate 1 arranged at the bottom are provided with a quadrangular cutout portion for forming the electronic component housing hole 2, and the organic substrate 1 and the adhesive material 7 are attached. As shown in FIG. 1 (a), a multilayer board 15 is formed by laminating, then heating, pressing and adhering to form an integrated electronic component housing hole 2 in which the conductor circuit 4 is exposed at the step portion, and an integrated multi-layer board 15. Obtained.

Next, as shown in FIG. 1 (b), through holes 3 were formed by drilling in the parts other than the electronic component housing holes 2 of the multilayer board 15. Then, an alkali peeling dry film (product number 411Y-50 manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) is attached to both surfaces of the multilayer plate 15 using a laminator to cover the electronic component storage hole 2 and the through hole 3, and then, As shown in FIG. 1 (c), the dry film is exposed and developed to remove the dry film in the portion facing the through hole 3 and leave the dry film in the portion covering the electronic component storage hole 2 as it is. A film body 8 was formed to cover the electronic component storage hole 2. The development of the dry film was performed using an aqueous sodium carbonate solution.

Next, as shown in FIG. 1 (d), colloidal palladium is attached to the through holes 3 using a plating pretreatment liquid, and then palladium is activated to remove the organic polymer covering the palladium. To form a film of the nucleus 6 for plating. In this case, the plating core 6 was also attached to the surface of the film body 8.

Next, an alkaline peeling type dry film (product number 411Y-50 manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) is used as a masking material 10 so as to mask the plating core 6 attached to the surface of the film body 8. This dry film was attached to both surfaces of the multilayer board 15 using a laminator, and then exposed and developed to cover the surface of the film body 8 with the masking material 10 as shown in FIG. 2 (e).

Then, as shown in FIG. 2 (f), the through-hole 3 is electrolytically copper-plated using a plating solution containing copper sulfate to form a metal film 9 of copper having a thickness of 20 μm.
Was formed. Then, the remaining dry film (the film body 8 and the masking material 10) was peeled off using an aqueous sodium hydroxide solution to expose the electronic component housing hole 2 as shown in FIG. 2 (g). At this time, the film body 8 and the masking material 10 could be completely removed.

Then, a nickel film of 5 μm is deposited on the metal film 9 formed in the conductor circuit 4 and the through hole 3 exposed in the electronic component housing hole 2 by electrolytic nickel plating using a Watts bath. A 2 μm thick gold film was deposited by electrolytic gold plating to obtain a multilayer printed wiring board (not shown). In the multilayer printed wiring board thus obtained, there was no abnormal deposition of nickel or gold between the conductor circuits 4 exposed in the electronic component housing hole 2, and therefore no short circuit failure occurred.

[0027]

According to the method for manufacturing a multilayer printed wiring board of the present invention according to claims 1 to 6, a plurality of organic substrates forming a conductor circuit are placed in an electronic component housing in which the conductor circuit is exposed. While forming holes at predetermined positions, they are laminated and adhered to form a multilayer board. Then, through holes are formed in the multilayer board at locations other than the electronic parts storage holes, and then the through holes are exposed to expose the electronic parts storage holes. After covering with a film body and sealing it, a nucleus for plating is applied to the through hole, plating is then applied to the through hole, and then the film body is removed, and then a metal by electrolytic plating is applied on the conductor circuit in the electronic component storage hole. Layers are formed to produce a multilayer printed wiring board, but when forming a metal film on the through holes, a masking material covers the top of the film body so that the plating cores are not exposed on the film body. Since it is, therefore plating metal strips on the film body is not precipitated. Therefore, according to the method for manufacturing a multilayer printed wiring board of the present invention according to claims 1 to 6, the troublesome work of removing the plated metal piece on the film body after forming the metal film in the through hole is unnecessary. Since the film body can be easily removed, the manufacturing efficiency is improved.

[Brief description of drawings]

FIG. 1 is a cross-sectional view schematically illustrating a method for manufacturing a multilayer printed wiring board according to the present invention.

FIG. 2 is a cross-sectional view schematically illustrating a method for manufacturing a multilayer printed wiring board according to the present invention with respect to steps subsequent to FIG. 1;

FIG. 3 is a cross-sectional view for explaining a model of a conventional method for manufacturing a multilayer printed wiring board.

FIG. 4 is a model cross-sectional view for explaining an improved example of the method for manufacturing the conventional multilayer printed wiring board shown in FIG.

[Explanation of symbols]

 1 Organic Substrate 2 Electronic Component Storage Hole 3 Through Hole 4 Conductor Circuit 5 Bottom Surface 6 Core for Plating 7 Adhesive Material 8 Film Body 9 Metal Film 10 Masking Material 11 Plated Metal Piece 15 Multilayer Board

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Hiroki Tamiya 1048, Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Works Co., Ltd.

Claims (6)

[Claims] 1. A multi-layer board is obtained by stacking and adhering a plurality of organic substrates forming a conductor circuit while forming an electronic component storage hole in which the conductor circuit is exposed at a predetermined position, and then forming a multilayer board. In the method for manufacturing a multilayer printed wiring board, a through hole is formed in a portion other than the electronic component housing hole of the multilayer board, and the through hole is plated to manufacture the multilayer printed wiring board. A method for manufacturing a multilayer printed wiring board, comprising the steps up to. (1) A step of covering the electronic component accommodating hole with a film body so as to expose the through hole in the multilayer board having the through hole formed (2) Pretreatment of the through hole is performed to form a nucleus for plating Step (3) Step of covering the film body with a masking material so as to mask the nucleus for plating adhered to the film body (4) Step of plating and forming a metal film in the through hole (5) Film Step of removing body and masking material (6) Step of forming a metal layer by electrolytic plating on the conductor circuit in the electronic component storage hole 2. The method for producing a multilayer printed wiring board according to claim 1, wherein the film body is a photosensitive dry film. 3. The method for manufacturing a multilayer printed wiring board according to claim 1, wherein the masking material is a photosensitive dry film. 4. The method for producing a multilayer printed wiring board according to claim 1, wherein the masking material is a plating masking film. 5. The method for manufacturing a multilayer printed wiring board according to claim 1, wherein the masking material is a liquid resist. 6. The method for manufacturing a multilayer printed wiring board according to claim 1, wherein the plating method in the step (4) is a direct plating method.