JP2001144390A - Solid circuit board and manufacturing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solid circuit board which can be manufactured with high producibility and a manufacturing method for manufacturing it and provide a solid circuit board, where the problem of rupture of a wiring layer caused when a manufacturing method of high producibility is adopted is resolved, and a manufacturing method for manufacturing it. SOLUTION: In manufacturing a solid circuit board, where a resin substrate 1 having a solid surface 3 is formed on the surface by pressing a resin board 5 and a copper foil 6 with heating dies 7, 8, the copper foil 6 is stuck to the formed solid surface 3, and the copper foil 6 is processed to a wiring layer 4 of a specified pattern, a copper foil, whose flexibility and elongation property are improved by heat treatment is used as the copper foil 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a three-dimensional circuit board and a method of manufacturing the same, and more particularly to a three-dimensional circuit board which can be manufactured with high productivity and has no break in a wiring layer, and a method of manufacturing the same.

[0002]

2. Description of the Related Art As a conventional method of manufacturing a three-dimensional circuit board,
For example, gluing a copper foil to a resin substrate having a three-dimensional shape,
There are a method of manufacturing a three-dimensional circuit board by removing the adhered copper foil by etching according to a circuit pattern, and a method of manufacturing a three-dimensional circuit board by forming a circuit pattern on a resin substrate having a three-dimensional shape by plating.

[0003]

However, according to the conventional method of manufacturing a three-dimensional circuit board, when a copper foil is bonded, it takes a long time to apply and solidify the adhesive, so that the productivity is poor, and the circuit is not good. In the case of plating a pattern, the plating time is long, which also results in poor productivity.

Accordingly, it is an object of the present invention to provide a three-dimensional circuit board that can be manufactured with high productivity and a manufacturing method for manufacturing the same. It is another object of the present invention to provide a three-dimensional circuit board in which breakage of a wiring layer caused when a manufacturing method with high productivity is adopted and a manufacturing method for manufacturing the same.

[0005]

In order to achieve the above object, the present invention provides a resin substrate having a three-dimensional surface formed on a surface thereof and a metal foil integrally attached to the three-dimensional surface of the resin substrate. A three-dimensional circuit board comprising a wiring layer having a predetermined pattern, wherein the wiring layer is made of a metal foil having improved flexibility and elongation characteristics by heat treatment. Things.

In order to achieve the above object, the present invention provides a method of manufacturing a three-dimensional circuit board having a wiring pattern of a predetermined pattern formed on a three-dimensional surface formed on a surface of a resin substrate.
Preparing a resin material to prepare a resin substrate, preparing a heat-treated copper foil by subjecting the copper foil to heat treatment under predetermined heat treatment conditions, disposing the heat-treated copper foil on the resin substrate The three-dimensional surface is formed on the resin substrate by pressing with a heating mold, and the heat-treated copper foil adhered to the three-dimensional surface of the resin substrate is attached to the three-dimensional surface. An object of the present invention is to provide a method for manufacturing a three-dimensional circuit board, wherein a predetermined patterning process is performed on a foil to form the wiring layer.

A copper foil is preferable as the metal foil, and a thermosetting resin such as an epoxy resin mixed with a filler such as glass fiber is preferable as a constituent material of the resin substrate. It is a preferred embodiment to increase the adhesive strength to the resin by roughening the surface of the metal foil in contact with the resin.

The present invention is characterized in that the copper foil constituting the wiring layer is annealed by heat treatment to improve the flexibility and elongation characteristics, thereby improving the shapeability of the copper foil when forming a resin substrate. As a result, the copper foil can respond to the flow of the resin when molding the resin substrate vertically and horizontally, and can be stuck to the three-dimensional surface formed on the resin substrate without difficulty. .

When a copper foil is used, the heat treatment temperature for obtaining the above effects is preferably set to 150 to 600 ° C. If the temperature is lower than 150 ° C., it is difficult to give sufficient elongation properties to the copper foil. Conversely, if the temperature exceeds 600 ° C., the tensile strength decreases due to the coarsening of the crystal grains of the copper foil,
The elongation decreases and it becomes difficult to use for use.

[0010] The copper foil which has been subjected to the heat treatment at a temperature in the range of 150 to 600 ° C has a content of 20 to 40% as compared with the copper foil which has not been subjected to the heat treatment.
Copper foil with improved elongation characteristics and reduced Vickers hardness (a measure of flexibility) of the copper foil surface by 10 to 30% is provided, and thus, the shapeability is improved by this. Is flexible and completely in close contact with the three-dimensional surface of the resin substrate.

The heat treatment is performed, for example, after raising the copper foil to a predetermined temperature at a rate of 2 to 5 ° C./min,
This is done by holding at that temperature for a minute and cooling at a rate of 2-10 ° C / min. Under these conditions, the heat treatment temperature of the copper foil is more preferably from 250 to 500C, and still more preferably from 300 to 400C.

As the form of the resin molded into the shape of the resin substrate by the heating mold, a granular or powdery resin may be used as it is, but the use of a resin molded in a solid form is more preferred. As an example of the latter, for example, it is conceivable to use an uncured thermosetting resin in the form of granules or powder in the form of a paste, and then form this into a plate. In this case, a resin plate is used. Molding can be performed with a smaller pressing force than usual, and the effect of reducing the burden on the copper foil can be obtained. The resin is preliminarily formed into a predetermined shape and then supplied to a heating mold press.

It is possible to pre-form the copper foil into a shape corresponding to a three-dimensional surface. This form is particularly advantageous when the height difference in the three-dimensional plane is so large that it exceeds the elongation and shapeability of the heat-treated copper foil. Preforming of copper foil,
Relieves the load of excessive elongation on copper foil during three-dimensional molding.

[0014]

Next, an embodiment of a three-dimensional circuit board and a method of manufacturing the same according to the present invention will be described. FIG.
This shows the configuration of a three-dimensional circuit board, where 1 is a resin board, 2
Is a concave portion formed on the surface of the resin substrate 1;
2 shows a three-dimensional plane.

Reference numeral 4 denotes a wiring layer formed on the three-dimensional surface 2,
This wiring layer 4 is made of heat-treated copper foil,
As a result, it is formed in a state where it is not broken in the following manufacturing process and does not allow excessive stress inside.

FIG. 2 shows a procedure for manufacturing the three-dimensional circuit board of FIG. Reference numeral 5 in (a) denotes a resin plate obtained by preforming a granular uncured epoxy resin containing a filler.
Is pressed together with the copper foil 6 by the heating dies 7 and 8 in the next step (b) to be cured and formed. The molding conditions of the heating molds 7 and 8 are as follows: temperature 180 ° C., pressure 7MP.
On the other hand, as the copper foil 6, a copper foil having a thickness of 18 μm which was heat-annealed at 350 ° C. for 80 minutes was used.

(C) shows the structure of the molded article. A three-dimensional surface 3 including a concave portion 2 is formed on the surface of the resin substrate 1 formed from the resin plate 5, and a copper foil 6 is integrally attached to the surface of the three-dimensional surface 3. I have. (D) shows a photo-etching process for the copper foil 6, in which a photoresist 9 is applied to the surface of the copper foil 6, exposure, development, etching and the like are performed, whereby a predetermined pattern as shown in (e) is obtained. Wiring layer 4 is formed.

FIG. 3A shows a completed structure in which a laminated plating film 10 of Ni (lower) and Au (upper) is formed on the wiring layer 4 by electroless plating. As a result of checking the wiring layer 4 before forming the plating film 10, no breakage occurred in the wiring layer 4 including the corner portion, and there was no problem in the finished product. The depth d ₁ of the recess 2 in this embodiment is 1 mm, and the angle of the inclined portion 2 ′ of the recess 2 is 4 mm.
5 ゜.

FIG. 3B shows a comparative example. In the manufacturing procedure of FIG. 2, a state before plating of a three-dimensional circuit board manufactured by using a normal electrolytic copper foil which is not heat-treated as the copper foil 6 and making the other parts the same is shown, where d ₂ =
It was confirmed that the copper foil 6 was torn due to the depth of 1 mm and the stretching force applied from the molds 7 and 8, and the broken portion 11 of the wiring layer 4 caused by this was spattered at the corner C. Was.
From the comparison between FIGS. 3A and 3B, the effect of the present invention of heat-treating the copper foil 6 is clear.

FIG. 4A shows another embodiment of the present invention, in which the depth d ₃ of the concave portion 2 is set to 2 mm, and the angle of the inclined portion 2 ′ of the concave portion 2 is set to 45 °. This is an example. FIG. 4B shows an example of use of the three-dimensional circuit board. On the surface of the wiring layer 4, a laminated plating film 10 of Ni and Au with Ni as a base is formed, and a semiconductor chip 12 is mounted on a central portion of the wiring layer 4. A predetermined portion between the electrode 13 of the semiconductor chip 12 and the wiring layer 4 is a bonding wire 1
4 and are entirely covered with a resin sealing material 15 to form a predetermined semiconductor package.

FIG. 5 shows a procedure for manufacturing the three-dimensional circuit board of FIG. The procedure is the same as that of FIG. 2 except that the molding shape of the resin substrate 1 is different, and the description is omitted. A three-dimensional circuit board was manufactured by using the same copper foil 6 and resin plate 5 as in FIG. 2 and setting the pressing conditions by the heating dies 7 and 8 to be the same as those in FIG.

Despite the fact that d ₃ of the recess 2 was set as deep as 2 mm, no breakage occurred in the wiring layer 4. In the comparative example, breaks frequently occurred at the corners.

FIG. 6 shows the state of occurrence of breakage in the comparative example. In the corner portion C, many breakage portions 11 were observed. In the case of a three-dimensional circuit board using an electrolytic copper foil without heat treatment, it has been confirmed that breakage occurs when the depth d ₃ of the concave portion 2 is 0.3 mm, and the breakage does not occur even at 2 mm. The effect is significant.

FIG. 7 shows an example in which a large number of three-dimensional surfaces are formed by a single molding, and the copper foil is adhered to the three-dimensional surface at a time. The feature is that a shape corresponding to a three-dimensional surface (not shown) to be formed is given.

It is suitable when the height difference on the three-dimensional surface is large, the stretching force applied to the copper foil 6 at the time of molding is relaxed, and the elongation and the shaping of the heat-treated copper foil 6 can be applied to the three-dimensional surface within an allowable range. Good pasting becomes possible. Reference numeral 16 denotes a hole-formed portion previously formed into a product shape by punching or photoetching, and 17 denotes a copper foil adhered on the back surface of the finished product to form a ground layer or the like. It is configured.

FIG. 8 shows still another configuration example of the three-dimensional circuit board obtained by the present invention. In FIG. 4, a plurality of three-dimensional surfaces 3 are formed on the resin substrate 1 by forming a plurality of heating dies 7 and 8, and a predetermined photo-etching is performed on the copper foil 6 formed on each of the three-dimensional surfaces 3 to perform wiring. After forming a layer, a through hole is formed at a predetermined position of the wiring layer 4, and a through hole 18 is formed by applying an electroless plating having a thickness of 0.05 μm to the inner surface of the through hole. 1
9 and cut pieces are used as individual three-dimensional circuit boards.

[0027]

As described above, according to the three-dimensional circuit board and the method of manufacturing the same according to the present invention, the resin is pressed by the heating die and the copper foil is attached to the three-dimensional surface of the molded resin substrate. It is superior in productivity to those that bond copper foil to a conventional three-dimensional resin substrate or form a circuit pattern of plating, and as a metal foil, improves flexibility and elongation characteristics by heat treatment. In addition, since the copper foil having improved shapeability is used, the copper foil is not broken when the resin substrate is formed. Therefore, according to the present invention, it is possible to provide a three-dimensional circuit board having high productivity and having no break in the wiring layer.

[Brief description of the drawings]

FIGS. 1A and 1B are explanatory views showing an embodiment of a three-dimensional circuit board according to the present invention, wherein FIG. 1A is a plan view and FIG.
FIG.

FIG. 2 is an explanatory view showing a manufacturing procedure for manufacturing the three-dimensional circuit board of FIG. 1;

3A and 3B are cross-sectional views of a three-dimensional circuit board, wherein FIG. 3A shows a three-dimensional circuit board based on the present invention, and FIG. 3B shows a three-dimensional circuit board of a comparative example.

FIGS. 4A and 4B are explanatory views showing another embodiment of the three-dimensional circuit board according to the present invention, wherein FIG. 4A is a perspective view, FIG. The configuration is shown.

FIG. 5 is an explanatory view showing a manufacturing procedure for manufacturing the three-dimensional circuit board of FIG. 4;

FIG. 6 is an explanatory view showing a state in which a wiring layer in a three-dimensional circuit board according to a comparative example is broken.

FIG. 7 is an explanatory view showing another embodiment of the method of manufacturing a three-dimensional circuit board according to the present invention.

FIG. 8 is an explanatory view showing another embodiment of the three-dimensional circuit board according to the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 resin substrate 2 recess 3 solid surface 4 wiring layer 5 resin plate 6 copper foil 7, 8 heating mold 9 photoresist 10 plating film

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hideyuki Sagawa 5-1-1 Hidakacho, Hitachi City, Ibaraki Prefecture Power Systems Research Laboratory, Hitachi Cable, Ltd. (72) Inventor Hideki Asano 5 Hidakacho, Hitachi City, Ibaraki Prefecture 1-1 1-1, Hitachi Cable, Ltd. Power Systems Research Laboratory (72) Inventor Naotake Ebinuma 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Pref. Hitachi Manufacturing Co., Ltd. (72) Inventor Shozo Nakamura Kanagawa 292 Yoshida-cho, Totsuka-ku, Yokohama-shi F-term in Hitachi, Ltd. Production Technology Laboratory (Reference) 4E351 AA01 BB01 BB30 BB33 BB38 BB50 CC22 CC31 DD04 DD06 DD19 EE10 GG20 5E338 AA05 AA16 BB63 BB75 CC01 CD05 EE27 EE31 5E339 AB02 AC02 BD11 BE11 CC01 CD01 CE16 CF16 CF17 DD02 EE05 FF02 FF03

Claims (6)

[Claims] 1. A three-dimensional circuit board comprising a resin substrate having a three-dimensional surface formed on a surface thereof, and a wiring pattern having a predetermined pattern formed by a metal foil integrally attached to the three-dimensional surface of the resin substrate. The three-dimensional circuit board, wherein the wiring layer is formed of a metal foil having improved flexibility and elongation characteristics by heat treatment. 2. The three-dimensional circuit board according to claim 1, wherein the metal foil is made of a copper foil, and the resin substrate is made of a thermosetting resin mixed with a filler. 3. A method of manufacturing a three-dimensional circuit board in which a wiring pattern having a predetermined pattern is formed on a three-dimensional surface formed on a surface of a resin substrate, wherein a resin material is preformed to prepare a resin substrate. Preparing a heat-treated copper foil by performing heat treatment under heat treatment conditions, forming the three-dimensional surface on the resin substrate by arranging the heat-treated copper foil on the resin substrate and pressing with a heating mold; Affixing the heat-treated copper foil to the three-dimensional surface, and applying a predetermined patterning to the heat-treated copper foil attached to the three-dimensional surface of the resin substrate to form the wiring layer. A method for manufacturing a three-dimensional circuit board. 4. The step of preparing the heat-treated copper foil is performed by annealing at a temperature of 150 to 600 ° C., and the size of crystal grains after annealing is 5 μm to 15 μm.
m and a twin structure, the elongation is 20% or more, and the Vickers hardness of the surface of the copper foil is H
4. The method for manufacturing a three-dimensional circuit board according to claim 3, wherein the value is v45 or less. 5. The method for manufacturing a three-dimensional circuit board according to claim 3, wherein in the step of preparing the resin substrate, a granular or powdery resin powder is compression-molded. 6. The heat-treated copper foil according to claim 3, wherein the step of attaching the heat-treated copper foil gives a three-dimensional shape corresponding to the three-dimensional surface to the heat-treated copper foil before forming the three-dimensional surface. 4. The method for manufacturing a three-dimensional circuit board according to claim 3.