JPH11251704A - Wiring board and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a hole as a blind through hole, by forming, in a conductor layer, a hole for conducting current between outer layer conductors on both faces with its inner wall being exposed, and blocking one end face section of the through hole by a thin insulating film, thereby forming a hollow non- through hole. SOLUTION: A specified through hole 3 is formed at a specified place in an insulating substrate 1 using a copper foil 2 which is substrate material. On an inner wall of the through hole 3 and on both faces of the copper clad laminate, a conductor layer 4 is formed by electroless plating, vapor deposition or the like. After that, the conductor layer 4 is etched to form a conductor circuit constituted of a desired upper outer layer surface conductor 6, a desired lower outer layer surface conductor 8, and a conductor layer 7 in the through hole 3 for making an electric conduction between the outer surface conductors on both faces of the insulating substrate 1. Then, a thin insulating film 9 is so formed on the upper outer layer surface conductor 6 and one end face of the through hole 3 as to block one opening of the through hole 3 and thereby a hollow non-through hole 5 is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a wiring board for mounting electronic components and a method of manufacturing the same.

[0002]

2. Description of the Related Art In the case of a wiring board having a through-hole such as a conventional through-hole, the flux, solder, solder paste, etc., when mounting electronic components on the wiring board are used. Adhesives for protecting the electronic component elements, electronic components, and the like, and molding resin as a coating material flow out through the through holes of the wiring board to the opposite side of the wiring board, resulting in poor quality. Therefore, in order to prevent the outflow, the inside of the through hole of the wiring board is filled with a filling material and cured to close the through hole. The filling state of this through hole is to fill the entire inside of the through hole with an insulating filling material,
Holes, such as through-holes, in which the inside of the cylinder is closed and hardened with a filling material are covered with a conductor layer on the inner wall of the holes, making it difficult to solder, and cannot be used as end electrodes for connection to other wiring boards.

Conventionally, a wiring board for mounting electronic parts such as an IC flat package, a semiconductor circuit element, a light emitting element, and a light receiving element has conventionally been manufactured by wire bonding mounting or surface mounting of a chip part in the process of manufacturing chip parts. After the mounting, the element and the bonding wire are molded and covered with a coating material such as a mold resin to protect the element. In this process, the molding resin is connected to the connection lands on the opposite side of the mounting surface of the electronic components, through the through holes such as through holes in the wiring board, to the through holes that require soldering, or to the outside of the wiring board And adheres to the end surface electrode or the like to cause poor quality. Therefore,
Prior to the step of covering with a mold resin or the like, a step of masking a through hole such as a through hole of a wiring board with a heat-resistant adhesive tape is required.

In particular, in order to make an electronic component comprising an electronic component element such as a semiconductor circuit element, a light emitting element, and a light receiving element into a chip part for mounting with a surface, an electrode for connecting to a counterpart wiring board is required. In many cases, an end face electrode is set on the end face of the chip component as this electrode. The end face electrode is formed by dicing and cutting the through-hole hole in half near the center of the hole. I have to. The through-hole for forming the end face electrode is formed by covering the electronic component element and the bonding wire with the mold resin, then dicing and cutting, and the wall surface of the through-hole is used as a soldering allowance. Insulating fillers cannot be filled and cured.

[0005] A conventional method of manufacturing a wiring board on which electronic components are mounted is a process of making a hole in an insulating base material or a double-sided copper-clad laminate, and forming a hole on the surface of the base material or the laminate and the inner wall of the through hole. Step of forming a copper plating layer, then applying an etching resist by silk screen printing or photographic method and then etching to form a conductor circuit, exposed surface conductors and inner walls of through holes and non-through holes A wiring board is manufactured in a step of performing Ni-Au plating or Ni-Ag plating.
Then, after the step of masking predetermined through-hole holes with a heat-resistant adhesive tape, the step of mounting and mounting electronic components on a wiring board, the step of covering electronic component elements and bonding wires, and the step of applying a masking tape. The step of dicing and cutting around the center of the predetermined through-hole is used as a chip component for mounting with a surface.

Further, conventionally, the process of masking a through-hole for forming an end surface electrode with a heat-resistant tape is inefficient and the adhesion quality of the heat-resistant tape is unstable. Since the through-hole hole is closed by the inner layer conductor of the plate, a so-called blind through-hole hole structure is supported, and the manufacturing cost is considerably high.

[0007]

As described in the prior art, when an electronic component is mounted and mounted on a wiring board or covered with a mold resin, flux, solder, solder paste, adhesive, mold resin, etc. The coating material, such as a surface treatment agent, flows out from the through hole of the wiring board to the opposite side of the wiring board, resulting in poor quality. Further, a masking tape attaching operation is required to prevent the outflow of the substance. Therefore, it is necessary to form a non-through hole that does not flow out.

However, in order to form a chip component or a module substrate composed of an electronic component element, an end face electrode to be connected to another wiring board is required, and the inner wall of the end face electrode has a solderability. It is a condition that it is formed of a good conductor layer and is exposed on the end face of the wiring board or chip component. In other words, while providing a wiring board having an end surface electrode in which the inner wall of the hole is exposed in the conductor layer while being a non-through hole, such a wiring board has good work efficiency and is a blind through-hole with low manufacturing cost. It is an object of the present invention to provide a method of manufacturing as. And
The wiring board or chip component, in which the inner wall of the non-through hole is formed of a conductive layer having good solderability and the end surface conductor layer exposed on the end surface of the wiring board or chip component is used as a soldering allowance for soldering, and It is a second object to provide a manufacturing method.

[0009]

According to the present invention, there is provided a wiring board for mounting an electronic component or an electronic component element, comprising: an insulating substrate or a copper-clad laminate;
Solder provided with a hole penetrating the insulating base material or the copper-clad laminate, outer conductors on both surfaces of the insulating base material or the copper-clad laminate, and inner walls of the holes for conducting the outer conductors on the two surfaces exposed. A conductive layer having good adherence, and an electronic component mounting side of the conduction hole, that is, a heat-resistant good and thin insulating film formed from a photocurable photosensitive film that closes one end surface of the conduction hole. It is possible to provide a wiring board having a non-through hole in which the inside of the insulating film becomes hollow. The wiring board of the present invention may be a single-sided board or a multi-layered wiring board, and the non-through holes can be provided in a lower portion for mounting a component or for covering an electronic component, and in a predetermined position as an end surface electrode.

Further, in an end surface wiring board and a chip component in which a substantially central portion of the non-through hole is precisely cut to form a semi-cylindrical shape or a conduction groove of a U-shaped groove, the wiring board or the chip component is exposed on the substrate end surface. A conductive groove having a semi-cylindrical shape or a U-shaped groove, a conductive layer formed on the inner peripheral surface of the conductive groove and having good solderability and conducting the outer layer conductors on both sides of the wiring board; A conductive thin film on both surfaces of the wiring board in contact with the conductive groove of the groove, and a heat-resistant and thin insulating film formed from a photocurable photosensitive film that covers one of the conductive grooves, that is, a groove end surface on the electronic component mounting side; And a chip component having an end surface conductor layer having good solderability of the end surface electrode composed of the above. The conductor layer on the inner peripheral surface of the conductive groove, which covers one of the groove end surfaces by the insulating film formed by the present invention, is an end surface terminal for securing a soldering allowance, and therefore, high quality in solderability is desired.

Further, in an electronic component mounted on a surface outer layer conductor of a wiring board with a surface, that is, in a chip component, a semi-cylindrical shape or a U-shape formed by exposing to an end surface of an insulating base material serving as a base material of the wiring board. A conductive groove of the groove, a conductive layer having good solderability formed on the inner peripheral surface of the conductive groove, a double-sided outer layer conductor of the wiring board in contact with the conductive groove of the semi-cylindrical shape or the U-shaped groove, and the conductive groove In other words, it is possible to provide a chip component having a thin insulating film for closing the groove end surface on the electronic component mounting surface side and an end surface conductor layer having good solderability of the end surface electrode and having an end surface terminal of the electronic component.

Such a wiring board and a chip component are
It can be manufactured by the following steps. A) Step of drilling holes in copper-clad laminate (shown in FIG. 4A) B) Step of forming a conductor layer on the surface of the copper-clad laminate and the inner wall of the hole (shown in FIG. 4B) C) Step of forming an etching resist and removing unnecessary metal conductors to form a conductor circuit (shown in FIG. 4C). D) One predetermined outer surface conductor and one of the through holes. Step of forming a heat-resistant insulating film with a photocurable photosensitive film that covers the end face (shown in FIG. 4D) E) Next, if necessary, a predetermined exposed outer layer surface A wiring board is formed in the step of forming a foreign metal plating layer on the conductor and the conductor layer on the inner wall of the hole. F) A step of mounting and mounting an electronic component on the wiring board formed by the above steps (shown in FIG. 4F). G) A step of coating the electronic component with a coating material if necessary (FIG. 4). (G).) H) Thereafter, a step of cutting a substantially central portion of the non-through hole in which the end surface of the one hole is closed to form a semi-cylindrical conductive groove (shown in FIGS. 2 and 3). According to such a process, a chip component having an end surface electrode on one end surface of which is closed by a semi-cylindrical conductive groove on the end surface of the wiring board. The step of forming a foreign metal plating layer in the step E) may be performed before the step of forming an insulating film in the step D).

In some cases, it is possible to carry out the step of cutting the substantially central portion of the non-through hole, which is the step H), before the steps F) and G), but thereafter mounting and mounting the electronic components on the wiring board. There is a danger that flux, solder, solder paste, adhesive, coating material, surface treatment agent, etc. may flow out from the end surface electrode portion of the wiring board cut into a small size during the work or the coating work.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. First, a description will be given of a method of manufacturing a chip component by mounting a surface on a wiring board and the surface of the wiring board by the process shown in FIG. As shown in FIG. 4A, a double-sided copper-clad laminate MCL-E-67 (trade name, manufactured by Hitachi Chemical Co., Ltd.), in which 18 μm or A predetermined through hole 3 is formed at a desired position by a drill using a substrate material having a total thickness of 0.3 mm with a copper foil 2 of 35 μm. The substrate of the wiring substrate is a glass epoxy substrate, a phenol substrate, a synthetic resin substrate, a Teflon-containing substrate, a polyimide resin substrate, a BT resin (bismaleimide-triazine resin) substrate, a modified B
Either a T resin base or an insulating base such as ceramic may be used. Next, as shown in FIG. 4B, the conductor layer 4 is coated on both surfaces of the copper-clad laminate and the inner wall of the through-hole 3 by electroless plating, electrolytic plating, or vapor deposition to a thickness of 10 μm to 25 μm.
μm is formed. In this embodiment, copper plating is used. Then, as shown in FIG. 4C, an etching resist having a desired pattern is formed at a predetermined location by a silk screen printing method or a photolithography method in which a photosensitive film is laminated, exposed and developed, and then unnecessary. The conductive metal conductor is dissolved and removed by etching, and then the etching resist film is peeled off, and the desired upper outer surface conductor 6, lower outer surface conductor 8, and outer surface conductors on both surfaces of the insulating base material 1 are electrically connected. To form a conductor circuit composed of the conductor layer 7 inside the through-hole to be conducted.

Thereafter, as shown in FIG. 4D, one predetermined outer layer surface conductor, that is, the upper outer layer surface conductor 6 on which the chip component is mounted and mounted, and one hole end face of the through hole 3, ie, the chip component. Photocurable photosensitive film SR-2300G or SR-3000 so as to cover the end face of the hole on the mounting side
(Both trade names, manufactured by Hitachi Chemical Co., Ltd.) using a vacuum laminator, and laminated by 250 mj / cm ²
Exposure is performed at an exposure amount of up to 700 mj / cm ² , developed, dried, post-exposed, and heat-cured at 140 ° C. to 170 ° C. for 40 minutes to 90 minutes to obtain a thin insulating film 9 having a thickness of 50 μm to 80 μm and having good heat resistance. Is formed to form a non-through hole 5 for closing one end face of the conduction hole with the insulating film 9.

Next, in the case where the electronic component element or electronic component is wire-bonded to a wiring board, or when required for high quality solderability, Ni-Au is added to the outer layer surface conductor and the conductor layer on the inner wall of the hole. Plating, Ni-Ag plating, Ni-S
The step of forming a metal plating layer different from a normal metal conductor layer such as n-plating or solder plating is performed after the step of forming a conductor circuit shown in FIG.
After the step of forming the insulating film shown by, a predetermined foreign metal plating layer as shown above can be formed. In particular, the photosensitive film SR-3000 (trade name, manufactured by Hitachi Chemical Co., Ltd.) is suitable for a photo-additive method with good plating resistance in which metal plating is performed after forming a predetermined insulating film 9.

FIG. 4 shows the wiring board 10 formed by the above process.
As shown in (f), the electronic component element 40 is mounted and fixed on a predetermined portion of the wiring board 10 with an adhesive 42, and the electronic component element 4
0 and the connection lands of the wiring board 10 are electrically connected by the bonding wires 41 by the wire bonding method. If the electronic component element 40 has the shape of a surface-mounted component, it is mounted on the surface by reflow soldering and is electrically connected to the connection lands of the wiring board 10. In addition, the work of mounting and mounting the electronic component elements 40 and the electronic components on the separately divided wiring board 10 reduces the work efficiency, and the work is performed on the opposite side of the wiring board in the next covering step. Since the coating material 43 easily flows out, the individual wiring boards 10 are repeatedly formed in the non-through holes 5 formed in the step of FIG. Often rubs.

Then, if necessary, as shown in FIG. 4 (g), an insulating material, a molding resin, or the like for protecting the mounted electronic component element 40, the electronic component, the bonding wire 41, and the like. It is covered with a covering material 43 such as a covering resin. The component mounting process shown in FIG.
In the step (g) of coating with the coating material, no through-hole is formed in the wiring board 10, and conduction is performed to conduct the double-sided outer layer conductors disposed below the electronic component element 40, the adhesive 42, and the coating material 43. All of the holes and the conductive holes for forming the end face electrodes to be connected to other wiring boards are non-through holes for closing one end face of the conductive holes, that is, the hole end face of the mounting surface of the electronic component element 40 with the insulating film 9. Since it is 5, flux, solder, solder paste, adhesive, coating material, surface treatment agent and the like do not flow out to the opposite surface side of the wiring board.

Thereafter, as shown in FIG. 4 (g), a substantially central portion (X-Y) of the non-through hole 5 in which the end surface of one of the holes for the end surface electrode is closed with the insulating film 9 is superposed on a semiconductor element or the like. The conductive grooves such as semi-cylindrical shapes and U-shaped grooves are formed as end electrodes by cutting with dicing cut, which is a method of precision cutting, which is used as a soldering allowance for module wiring boards and chip components. The cutting method is not limited to the dicing cut, but may be V-cut cutting, saw-tooth cutting, or laser light cutting.

FIG. 1 shows a state in which an end face electrode is formed as a wiring board in the above-mentioned manufacturing process. After the step of forming an insulating film that closes one end face of the through conduction hole shown in FIG. 4D, the non-through hole 5 in which one end face of the hole serving as the end face electrode is closed with the insulating film 9. Almost in the center (X-
Y) is ultra-precisely cut with a cutting width of 0.05 mm to 0.20 mm to form a semi-cylindrical shape or a U-shaped conductive groove as an end surface electrode on the end surface of the wiring board. The configuration of the end surface electrode is a semi-cylindrical or U-shaped conductive groove 15 formed on the end surface of the insulating substrate 1 and a conductor layer 7 inside a hole formed on the inner peripheral surface of the conductive groove 15. An outer layer surface conductor on both sides of the upper outer layer surface conductor 6 and the lower outer layer surface conductor 8 in contact with the conductive groove 15;
This is a wiring board having an end face electrode 20 including a thin insulating film 9 having good heat resistance and covering one end face of the conductive groove 15.

FIG. 3 is a perspective view of the end face electrode 20. One of the conductive grooves 15 having a semi-cylindrical shape or a U-shaped groove exposed to the end face of the insulating substrate 1, that is, the conductive groove end face on the electronic component element or electronic component mounting surface side is covered with the insulating film 9. The conductor layer 7 inside the hole formed on the inner peripheral surface of the conduction groove 15 connected to the wiring board by soldering must have good solderability in order to provide a soldering allowance.

The electronic component and the electronic component element 40 shown in FIG.
4g on the wiring board and the step of coating the mounted electronic component, the electronic component element 40, the bonding wire 41, and the like with the coating material 43 in FIG. A substantially central portion (X-Y) of the non-through hole 5 in which one end face is closed by the insulating film 9 is ultra-precisely cut to produce a chip component 30 as shown in FIG. The end surface electrode of the chip component 30 has a semi-cylindrical or U-shaped conductive groove 15 formed on the end surface of the insulating base material 1 and a conductive layer inside a hole formed on the inner peripheral surface of the conductive groove 15. 7, an outer surface conductor on both sides in contact with the conductive groove 15, and an insulating film 9 having good heat resistance for covering one groove end face of the conductive groove 15
And a chip component 30 having an end electrode terminal composed of: The conductor layer 7 inside the hole formed on the inner peripheral surface of the conductive groove 15 may be formed with a Ni-Au plating layer on a normal copper plating layer in order to improve solderability. A Ni-Au plating layer is often formed on a wiring board for bonding connection.

[0023]

(1) An electronic component or an electronic component element is mounted and mounted on a wiring board by forming a non-through hole having a blind through-hole hole structure in which one end face of a conduction hole is closed with an insulating film. Flux, solder, solder paste, adhesive, coating material, surface treatment agent, etc. leaks to the opposite side of the wiring board during the process and the process of coating the mounted component with a coating material such as an insulating material or mold resin Is gone. (2) A substantially central portion of a non-through hole in which one end surface of the conduction hole is closed with an insulating film is cut, and a conduction groove of a semi-cylindrical shape or a U-shaped groove is formed on an end surface electrode of a wiring board or a chip component. The conductive layer on the inner peripheral surface of the conductive groove is not contaminated with an insulating material such as the adhesive or the coating material described in (1) above, so that it has good solderability. Furthermore, there is no need for a conventional work of filling a filling material into a through-hole and a masking tape work, so that work efficiency is improved, manufacturing costs are reduced, and a wiring board, a chip component, and a method for manufacturing the same with high connection reliability are provided. Can be.

[Brief description of the drawings]

FIG. 1 is a sectional view of a wiring board having end electrodes according to the present invention.

FIG. 2 is a sectional view of a chip component having a terminal according to the present invention.

FIG. 3 is a perspective view of an end face electrode portion of the present invention.

FIG. 4 is a sectional view of a manufacturing process of the wiring board and the chip component of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Insulating base material 2 ... Copper foil 3 ... Through-hole 4 ... Conductor layer
DESCRIPTION OF SYMBOLS 5 ... Non-through-hole 6 ... Upper outer layer surface conductor 7 ... Conductor layer inside a hole 8 ... Lower outer layer surface conductor 9 ... Insulating film 10 ... Wiring board 15 ... Conduction groove 20 ... End face electrode 30 ... Chip component 40 ... Electronic component element 41 ... bonding wire 42 ... adhesive 43 ... coating material

Claims (3)

[Claims] In a wiring board, an insulating base material, a hole penetrating the insulating base material, outer conductors on both sides in contact with the through hole, and a conductor provided on an inner wall of the hole for conducting the outer conductor on both sides. A wiring board having a non-through hole comprising a layer and an insulating film for closing one end face of the conduction hole. 2. A wiring board formed by cutting a substantially central portion of a non-through hole according to claim 1, wherein the conductive groove is exposed on an end face of the substrate and a conductive layer formed on an inner peripheral surface of the conductive groove. A wiring board, comprising: an end surface electrode comprising: a double-sided outer layer conductor in contact with the conductive groove; and an insulating film for closing one groove end surface of the conductive groove. 3. A method for manufacturing a wiring board, comprising the following steps. A) Step of drilling holes in the copper-clad laminate B) Step of forming a conductor layer on the surface of the copper-clad laminate and the inner walls of the holes C) Forming an etching resist, removing unnecessary metal conductors, and forming conductor circuits D) a step of forming a predetermined one outer layer conductor and an insulating film that closes one hole end face of the through hole E) If necessary, the exposed outer layer conductor and the conductor layer on the inner wall of the hole are different from each other. Forming a metal plating layer