JP2004079605A - Multilayer wiring substrate with built-in component, and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To receive no damage on components even when a through hole exposing a part of the component is formed by laser drilling in an insulating film covering the component when a multilayer wiring substrate with the built-in component is manufactured in the multi-layer wiring substrate with the built-in component and its manufacturing method. <P>SOLUTION: The multilayer wiring substrate with the built-in component is provided with an insulating layer 5 covering on the substrate 1 including passive components 3 such as a resistor, a coil and a capacitor mounted on the substrate 1 and forming a conductive paste film 4A at a via hole opposite position on the upper face, and the passive component 3 forming the conductive paste film 4A; and one or more leader via holes 5A formed on the insulating layer 5 existing just above the conductive paste film 4A. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a component-embedded multilayer wiring circuit board capable of incorporating passive components such as resistors, coils, and capacitors at a high density, and a method of manufacturing the same.
[0002]
[Prior art]
In general, when passive components such as resistors, coils, and capacitors are built in a multilayer wiring circuit board, the connection between those passive components and other parts is performed only on the circuit formed on the same surface of the board. Is done.
[0003]
In order to increase the density of a circuit board, it is necessary to shorten the length of wiring lead-out from the component as much as possible. For that purpose, the connection between the component and other parts is performed in the thickness direction of the substrate. It is necessary.
[0004]
At present, it is common to use laser drilling to form via holes for drawing wiring in the insulating film covering the component, but in this case, the upper surface of the component is often damaged by the laser. This is a major factor in lowering the production yield of the component built-in multilayer wiring circuit board.
[0005]
[Problems to be solved by the invention]
In the present invention, when manufacturing a multilayer wiring circuit board with a built-in component, even if a through hole for exposing a part of the component by laser drilling is formed in an insulating film covering the component, the component is not damaged. To try.
[0006]
[Means for Solving the Problems]
In the component-embedded multilayer wiring circuit board and the method of manufacturing the same according to the present invention, a conductive paste film (for example, conductive paste film 4A) is mounted on a substrate (for example, circuit board 1) at a position facing a via hole on the upper surface. A passive component (for example, passive component 3) such as a formed resistor, a coil, and a capacitor; an insulating layer (for example, insulating layer 5) covering the substrate including the passive component on which the conductive paste film is formed; Basically, one or more via holes (for example, via holes 5A) are formed in the insulating layer immediately above the conductive paste film for drawing out wiring.
[0007]
By taking the above means, when pulling out wiring from the components of the multilayer wiring circuit board incorporating passive components such as resistors, coils, capacitors, etc., in order to minimize the distance, laser drilling on the insulating film just above the components The surface of the component is not damaged even if a via hole is formed by the method described above, and an electrode made of a metal thin film having a thickness of 1 [μm] or less, which is usually damaged by a laser. Even if the component is formed on the surface of the component, it is easy to connect the electrode and the via conductor, and therefore the density and manufacturing yield of the multilayer wiring circuit board with a built-in component are dramatically improved, and the Manufacturing costs are reduced.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is a cutaway side view showing an essential part of a multilayer wiring circuit board with a built-in component for explaining a principle embodiment of the present invention. In the drawing, 1 is a circuit board, 2 is a wiring, and 3 is a built-in. 4 denotes a conductive paste, 4A denotes a conductive paste film, 5 denotes an insulating layer, and 5A denotes via holes.
[0009]
An outline of a process for manufacturing the illustrated multilayer wiring circuit board with a built-in component will be described.
(1) The passive component 3 is mounted on the circuit board 1 having the wiring 2, and the conductive paste 4 is applied on the upper surface of the passive component 3 to a thickness of about 10 μm to 20 μm to form the conductive paste film 4 </ b> A. To form
[0010]
(2) After forming the insulating layer 5 on the entire surface, drilling is performed using a CO ₂ laser to form a via hole 5A.
[0011]
In this case, the conductive paste film 4A is exposed at the bottom of the via hole 5A and is irradiated with the laser beam. However, since the surface of the passive component 3 is not directly irradiated, it is fatally damaged. Never.
[0012]
By employing the above-described process, a via hole can be formed immediately above the component mounted on the component-embedded multilayer wiring circuit board, and the wiring can be drawn out at the shortest distance, thereby causing damage to the component. In addition, even if the conductive paste film 4A receives laser irradiation, there is no possibility that its function is deteriorated.
[0013]
FIG. 2 to FIG. 5 are cutaway side views of a main part of a multilayer wiring circuit board with a built-in component at a key step for explaining a specific embodiment of the present invention. explain.
[0014]
2A. (1) Prepare a circuit board 11 and a component 12 on which components are to be mounted. The component 12 is a thin film resistor having a resistance value of 50 [Ω]. A Ni alloy resistor 12B having a thickness of 2 [μm] is formed on a polyimide film support 12A having a thickness of 5 [μm]. It has a structure in which a Cu electrode 12C of 0.5 [μm] and 1 [mm] □ is formed.
[0015]
In general, the production of the resistance value of a thin film resistor depends on the distance between the electrodes. Therefore, it is necessary to maintain a high patterning accuracy by reducing the thickness of the electrodes as much as possible.
[0016]
2B, the component 12 is fixed to the circuit board 12 using, for example, a thermosetting adhesive 13 which is an epoxy resin.
[0017]
3 (A) (3) A conductive paste film 14 having a thickness of 30 [μm] and a diameter of 400 [μm] is formed on the surface of the electrode 12C by applying the screen printing method.
[0018]
As the conductive paste in this case, a Cu powder in a thermosetting epoxy resin is used.
[% By weight] A dispersed one is used.
(4) After the conductive paste film 14 is formed by printing as described above, temporary heat curing is performed at a temperature of 100 ° C. for a time of 10 minutes to fix the conductive paste film 14 so as not to flow in a later step. .
[0019]
3 (B) (5) The insulating layer 15 and the Cu foil 16 are formed on the entire surface by applying the vacuum hot pressing method.
[0020]
During the vacuum hot pressing, the insulating layer 15 and the conductive paste film 14 were simultaneously cured by maintaining the temperature of 170 ° C. or more for 30 minutes or more.
[0021]
In this case, the constituent material of the insulating layer 15 is a material obtained by impregnating an uncured thermosetting epoxy resin into a glass cloth, the thickness is 100 [μm], and the Cu foil 16 has a thickness of 18 μm. [Μm] was used.
[0022]
Referring to FIG. 4A, (6) the Cu foil 16 is etched to a diameter of 300 [μ] by applying a resist process in the lithography technique and a wet etching method.
m] is formed.
[0023]
4 (B) (7) Through the opening 16A formed in the Cu foil 16, the diameter of the insulating layer 15 on the surface side is 100 [μm] and the diameter of the bottom is formed by carbon dioxide laser drilling. A via hole 15A of 70 [μm] is formed.
[0024]
In this case, if the conductive paste film 14 does not exist, the Cu electrode 12C exposed on the bottom surface of the via hole 15A is damaged by the energy of the carbon dioxide gas laser. Only the cured conductive paste film 14 is present at the bottom.
[0025]
Referring to FIG. 5 (8), after forming the via hole 15A, a wiring pattern 17 that is conductively connected to the Cu electrode 12C via the conductive paste film 14 is formed by using standard steps of electroless plating, electrolytic plating, and etching. .
[0026]
(9) After the wiring pattern 17 was formed, the resistance value of the component 12 was measured using the wiring pattern 17, and it was confirmed that the resistance value was 50 [Ω] as before mounting.
[0027]
The present invention can be embodied in many forms including the above-described embodiment, and will be exemplified below as additional notes.
[0028]
(Appendix 1)
Passive components such as resistors, coils, capacitors, etc., with a conductive paste film formed on the upper surface facing the via hole on the substrate,
An insulating layer covering the substrate including the passive component on which the conductive paste film is formed, and one or more wiring vias formed on the insulating layer immediately above the conductive paste film; A multilayer wiring circuit board with a built-in component, comprising: a hole;
[0029]
(Appendix 2)
The built-in component according to (Supplementary Note 1), wherein the wiring of the passive component is drawn out from the via hole formed immediately above the conductive paste film in the passive component via the conductive paste film. Multilayer wiring circuit board.
[0030]
(Appendix 3)
2. The multilayer wiring circuit board with a built-in component according to claim 1, wherein the passive component is a capacitor having a metal electrode having a thickness of 1 [μm] or less formed on both surfaces of an insulating film.
[0031]
(Appendix 4)
Mounting passive components such as resistors, coils, and capacitors on the board;
Forming a conductive paste film by applying a conductive paste to a via-hole facing region on the upper surface of the passive component;
Forming an insulating layer covering the entire surface including the passive component on which the conductive paste film is formed;
Forming a via hole by laser drilling an insulating layer immediately above the conductive paste film in the passive component.
[0032]
(Appendix 5)
The method for manufacturing a multilayer wiring circuit board with a built-in component according to (Appendix 4), wherein the conductive paste film is cured by the energy of the laser drill when the via hole is formed by laser drilling.
[0033]
【The invention's effect】
In the component-embedded multilayer wiring circuit board and the method of manufacturing the same according to the present invention, a conductive paste film is provided at a position facing a via hole on the upper surface of a passive component such as a resistor, a coil or a capacitor mounted on the board. Is formed on the substrate, including the passive component on which the conductive paste film is formed, and the insulating layer immediately above the conductive paste film is covered with an insulating layer. Is formed.
[0034]
By taking the above configuration, when drawing out wiring from the components of a multilayer wiring circuit board incorporating passive components such as resistors, coils, capacitors, etc., in order to minimize the distance, laser drilling is performed on the insulating film located directly above the components. The surface of the component is not damaged even if a via hole is formed by the method described above, and an electrode made of a metal thin film having a thickness of 1 [μm] or less, which is usually damaged by a laser. Even if the component is formed on the surface of the component, it is easy to connect the electrode and the via conductor, and therefore the density and manufacturing yield of the multilayer wiring circuit board with a built-in component are dramatically improved, and the Manufacturing costs are reduced.
[Brief description of the drawings]
FIG. 1 is a cutaway side view showing a main part of a multilayer wiring circuit board with a built-in component for explaining Embodiment 1 of the present invention.
FIG. 2 is a cutaway side view of a main part of the multilayer wiring circuit board with a built-in component at a key point in a process for explaining a specific embodiment of the present invention.
FIG. 3 is a cutaway side view of a main part of a multilayer wiring circuit board with a built-in component at a key step for explaining a specific embodiment of the present invention.
FIG. 4 is a cutaway side view of an essential part of a multilayer wiring circuit board with a built-in component in a process essential point for explaining a specific embodiment of the present invention.
FIG. 5 is a cutaway side view of a main part of the multilayer wiring circuit board with a built-in component at a key step in the process for explaining a specific embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Circuit board 2 Wiring 3 Built-in component 4 Conductive paste 4A Conductive paste film 5 Insulating layer 5A Via hole

Claims (3)

Passive components such as resistors, coils, capacitors, etc., with a conductive paste film formed on the upper surface facing the via hole on the substrate,
An insulating layer covering the substrate including the passive component on which the conductive paste film is formed, and one or more wiring vias formed on the insulating layer immediately above the conductive paste film; A multilayer wiring circuit board with a built-in component, comprising: a hole; 2. The component built-in multilayer according to claim 1, wherein a wiring of said passive component is drawn out from a via hole formed immediately above said conductive paste film in said passive component via said conductive paste film. Printed circuit board. Mounting passive components such as resistors, coils, and capacitors on the board;
Forming a conductive paste film by applying a conductive paste to a via-hole facing region on the upper surface of the passive component;
Forming an insulating layer covering the entire surface including the passive component on which the conductive paste film is formed;
Forming a via hole by laser drilling an insulating layer immediately above the conductive paste film in the passive component.

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