JP2004221330A - Electronic circuit board and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electronic circuit board that is highly dense, compact and small in thickness. <P>SOLUTION: The electronic circuit board 10 is provided with a plurality of small electronic circuit boards Pa an Pb having different electrical characteristics that are united on a fixing base 1, and a wiring layer such as a part mounting land 8 or the like is formed on the upper surface of their outermost layer. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an electronic circuit board, and more particularly to an electronic circuit board having a structure in which a plurality of different kinds of small electronic circuit boards are integrated, and a method of manufacturing the same.
[0002]
[Prior art]
First, the structure of a conventional electronic circuit board will be described.
[0003]
2. Description of the Related Art Conventionally, in the case of an electronic device in which electronic circuits such as RF (radio frequency), baseband, and power supply are mixed, an electronic circuit board is configured for each electronic circuit block and connected with a flexible substrate or connected to a base. It is configured by a method such as mounting them on a circuit board. When configuring on a single board, the optimum permittivity of the board required for each electronic circuit block is different, so when designing the board, it is necessary to take into account the thickness of the insulating layer and the width of the wiring. In order to supplement the required electrical characteristics, new components were mounted.
[0004]
[Problems to be solved by the invention]
However, conventional electronic circuit boards are limited in thickness and component mounting area on the outermost layer surface like portable electronic devices, and in recent years, portable electronic devices have become increasingly smaller, thinner and lighter. Is no longer able to satisfy the requirements for
[0005]
The present invention has been made in view of such a conventional problem, and an object of the present invention is to integrate a plurality of different types of small electronic circuit boards and to stack the same wiring layer to achieve individual It is an object of the present invention to enhance the function of a small electronic circuit board or individual electronic circuit blocks, and at the same time, to realize a small and thin electronic circuit board.
[0006]
It is another object of the present invention to apply a thin film forming technique generally used in a semiconductor device manufacturing process to realize a fine wiring and a built-in passive element which cannot be found in a conventional electronic circuit board.
[0007]
[Means for Solving the Problems]
Therefore, the electronic circuit board of the present invention solves the above-mentioned problem by a structure in which a plurality of small electronic circuit boards having different electric characteristics are integrated. Forming a wiring layer such as a component mounting land on the upper surface of these small electronic circuit boards, the wiring layer may be formed using a thin film forming technique, and further, a passive element is incorporated using the thin film forming technique. But it is good.
[0008]
Further, the method of manufacturing an electronic circuit board according to the present invention is a step of arranging small electronic circuit boards manufactured for electronic circuits having different requirements on a plane of a common fixed base such that one side thereof is on the same plane. And filling and curing an electrically insulating resin between and around the arranged plurality of small electronic circuit boards to integrate them, and then forming the integrated plurality of small electronic circuit boards. The above problem has been solved by adopting a manufacturing process including a step of forming a wiring layer by a thin film forming technique and a step of forming an insulating layer by leaving a component mounting land on the insulating layer as necessary. .
[0009]
Therefore, according to the present invention, it is possible to integrate small electronic circuit boards having different electrical characteristics, to mount the electronic circuit boards at a higher density within a certain thickness, and to realize a smaller and thinner electronic device. can do.
[0010]
Further, by forming a wiring layer above the integrated small electronic circuit board by a thin film forming technique, fine wiring not available in the conventional printed wiring board can be realized.
[0011]
Further, by incorporating passive elements, further miniaturization can be realized, the wiring length can be shortened, and the electrical characteristics can be improved.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the configuration and structure of an electronic circuit board according to an embodiment of the present invention will be described with reference to the drawings.
[0013]
FIG. 1 is a sectional view showing a manufacturing process of an integrated substrate which is a semi-finished product of an electronic circuit board according to an embodiment of the present invention, and FIG. 2 is a manufacturing process of obtaining an electronic circuit board of the present invention from a wiring process following FIG. FIG.
[0014]
First, a method for manufacturing an electronic circuit board according to an embodiment of the present invention will be described with reference to FIG.
[0015]
As shown in FIG. 1A, a small electronic circuit board Pa (hereinafter simply referred to as “board Pa”) having different circuit characteristics and a small electronic circuit board Pb (hereinafter simply referred to as “board Pb”) having different circuit characteristics are provided on the plane of the fixed base 1. "). In the illustrated example, for simplification of the drawing, these substrates Pa and Pb are shown as three-layer substrates, but are generally used multilayer substrates such as a two-layer substrate and a four-layer substrate. It should be added in advance that this may be possible.
[0016]
And here, different types of substrates are assumed to have different electrical characteristics such as dielectric constant, but are not limited to organic substrates, and the materials of the substrates are not limited, such as ceramic substrates, metal substrates, and silicon substrates. Absent. Further, the present invention is not limited to the size, and the substrates may have different numbers of layers and different thicknesses. Further, it may be an electronic circuit board for each function of an electronic circuit such as an RF circuit, a baseband, and a power supply.
[0017]
Although only two types of substrates Pa and Pb are shown in the drawing, two or more types of a plurality of small electronic circuit substrates may of course be arranged.
[0018]
The material of the fixed base 1 is, for example, glass, silicon, or the like, and it is important that the surface be flat.
[0019]
Next, as shown in FIG. B, an electrically insulating resin (hereinafter, simply referred to as “resin”) 2 such as an epoxy resin is printed between and around the substrate Pa and the substrate Pb by a printing method. Filling using such as. In this case, in order to reduce the size, it is desirable that the amount of the resin 2 is as small as possible. However, the filling range is not particularly limited, and unnecessary portions may be removed by cutting later.
[0020]
Next, as shown in FIG. 7C, after the resin 2 is cured to integrate the substrates Pa and Pb, the integrated substrates Pa and Pb are peeled off from the fixed base 1. The peeled surface 3 has the same plane on one side of the plurality of substrates Pa and Pb.
[0021]
Thus, the integrated substrate 4 of the plurality of substrates Pa and Pb is obtained. It should be noted that the orientation of the integrated substrate 4 shown in FIG. C is drawn with the peeled surface 3 facing upward.
[0022]
Next, a process of forming a wiring layer on the upper surface of the peeled surface 3 (hereinafter, referred to as “substrate surface 3”) of the integrated substrate 4 will be described with reference to FIG.
[0023]
First, as shown in FIG. 2A, a photosensitive insulating layer 5 is formed on the coplanar substrate surface 3. The insulating layer 5 was formed by applying, for example, liquid benzocyclobutene (BCB) by spin coating. However, the method for forming the insulating layer 5 is not limited to the spin coating method, and a dry film, curtain coating, spin coating printing, or the like can also be used.
[0024]
Next, a via hole 6 is formed in the insulating layer 5 as shown in FIG. In the present invention, since the photosensitive BCB is used, the via hole 6 is formed by exposing and developing using a mask pattern (not shown).
[0025]
Subsequently, as shown in FIG. 5C, an electrode layer 7 of, for example, copper (Cu) is formed on the entire surface of the insulating layer 5 and the via hole 6 by a sputtering method and a plating method, and this electrode layer 7 is In the next step shown in (1), component mounting lands, wiring (hereinafter simply referred to as “component mounting lands”) and the like are patterned to form component mounting lands 8.
[0026]
Next, in the step of FIG. E, a solder resist layer 9 is formed and protected on the outermost layer except for the component mounting lands 8.
[0027]
As described above, it is possible to obtain the electronic circuit board 10 of the present invention having a structure in which a plurality of boards Pa and Pb having different electrical characteristics, in which the component mounting lands 8 and the connection wiring are provided on the outermost layer through the steps described above, are integrated. . The thickness of a conventional substrate having a built-in LCR (coil, capacitor, resistor) is about 1 mm, whereas that of the thin film substrate of the present invention is about 0.05 mm.
[0028]
The steps A to C shown in FIG. 1 and the steps A to E shown in FIG. 2 can be repeated as necessary, and the layers can be freely stacked. Alternatively, layers can be stacked. In the above embodiment, the thin film forming technique is used in the manufacturing process. However, the present invention is not limited to the use of such a thin film forming technique, but uses a conventional electronic circuit board manufacturing process. It does not matter.
[0029]
Further, in the present invention, a passive element (not shown) is simultaneously formed on the layer formed by the thin film forming technique, for example, in the component mounting land 8 in the above embodiment, and an insulating layer or a solder resist layer is formed. May be formed and embedded in the electronic circuit board 10.
[0030]
As described above, the different types of substrates Pa and Pb are integrated, and a more miniaturized electronic circuit board 10 capable of high-density mounting can be manufactured.
[0031]
【The invention's effect】
As is clear from the above description, according to the present invention,
1. 1. Small electronic circuit boards having different electrical characteristics can be integrated. 2. It can be mounted at a higher density within a certain thickness. 3. Passive elements can be built into an electronic circuit board which is an integrated board. As a result, higher-density mounting can be performed, and downsizing and thinning of electronic devices can be realized. 5. By forming a wiring layer using a thin film forming technique, it becomes possible to make fine wiring that is not present in conventional printed wiring boards. The wiring length can be shortened, and various excellent effects can be obtained, such as improvement in electrical characteristics, particularly, high-frequency characteristics.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view illustrating a process of manufacturing an integrated substrate which is a semi-finished product of an electronic circuit board according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view showing a manufacturing process for obtaining the electronic circuit board of the present invention from the wiring process following FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Fixed base, 2 ... (electric insulation) resin, 3 ... Release surface, 4 ... Integrated board (semi-finished product), 5 ... Insulation layer, 6 ... Via hole, 7 ... Electrode layer, 8 ... Component mounting land, 9: solder resist layer, 10: electronic circuit board of one embodiment of the present invention, Pa, Pb (small electronic circuit) board

Claims (7)

An electronic circuit board having a structure in which a plurality of small electronic circuit boards having different electrical characteristics are integrated. The electronic circuit board according to claim 1, wherein a wiring layer is formed on an upper surface of the plurality of small electronic circuit boards. 3. The electronic circuit board according to claim 2, wherein the wiring layer is formed by using a thin film forming technique. 4. The electronic circuit board according to claim 3, wherein a passive element is incorporated by using the thin film forming technique. A step of arranging the small electronic circuit boards manufactured for each of the electronic circuits with different requirements on a plane of a common fixed base such that one side thereof is on the same plane,
A step of filling an electric insulating resin between and around the plurality of arranged small electronic circuit boards, and curing and integrating them,
Forming a wiring layer on the integrated plurality of small electronic circuit boards by a thin film forming technique. 6. The method for manufacturing an electronic circuit board according to claim 5, comprising a step of forming an insulating layer on the wiring layer while leaving the component mounting lands. 6. The method according to claim 5, wherein when the wiring layer is formed by a thin film forming technique, a passive element is formed inside the wiring layer.

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