JP2002374070A - Printed board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a printed board technique, which can substantially house a mounting component in a printed board and which is suitable for a thin-film device. SOLUTION: Two or more printed boards 2, 3, each having a through-hole 6 of a space 4 for housing a component are superposed and adhered to at least one board. Bonding is preferably executed with an adhesive sheet 5. Since the component can be housed and mounted in this space 4, a substantially flat board can be obtained, readily reduced in the thickness, and suitably used for a thin device. The number of components to be mounted can be increased.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a multilayer printed circuit board and a method for manufacturing the same. More specifically, the present invention relates to a multilayer printed circuit board that can be made almost flat without mounting a component so much when mounted.

[0002]

2. Description of the Related Art When parts such as ICs and capacitors are mounted on a conventional printed circuit board, parts of the parts inevitably protrude and do not become flat, are difficult to assemble. There are problems such as being unsuitable as a substrate. Therefore, a printed circuit board from which components do not protrude has been demanded. As such a board, a board in which a component mounting portion of a printed circuit board is cut by post-processing to form a concave portion and a component is mounted therein is conceivable. However, even with such a method, the connection between the component and the circuit is limited to the surface of the substrate, and cannot be internally connected. There is a problem that a circuit cannot be formed inside the substrate of the mounting portion.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a printed circuit board which can substantially accommodate mounted components inside the printed circuit board and is suitable for thin devices and a method of manufacturing the same.

[0004]

The inventor of the present invention has previously formed circuits on two or more printed boards, provided at least one of them with a space for accommodating components, and then bonded these printed boards. By doing so, the inventors have found that the above object can be achieved, and have reached the present invention. That is,
According to the present invention, two or more printed circuit boards on which circuits are formed are adhered, and at least one of them has a multilayer printed circuit board having a through portion which is a space in which components are stored, and a circuit is formed on each of them. And a method of manufacturing a multilayer printed circuit board, characterized in that two or more printed circuit boards each having a penetrating portion which is a space for accommodating components are superposed and bonded to at least one of them.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings.
FIG. 1 is a diagram showing a cross section of each element constituting the multilayer printed board of the present invention, and FIG. 2 is a diagram showing a cross section of the multilayer printed board of the present invention. In FIG. 1, reference numeral 2 denotes a lower printed board A, and reference numeral 3 denotes an upper printed board B. Necessary circuits are formed on both the printed boards A and B. Circuits are usually formed on both sides of each substrate, but need not be. These printed boards A and B may be prepared by a conventional method. The circuit may be subjected to a surface treatment on these substrates. Also, a solder resist may be applied. Reference numeral 6 denotes a through hole which is a conduction portion between the printed boards A and B, and reference numeral 8 denotes a through hole for conduction with components. The printed board B is provided with a through portion 4 which is a space for mounting and housing components in advance. The shape and size of the penetrating portion 4 may be appropriately determined according to the component to be mounted. In addition, the number may be set to a required number according to the number of mounted components.

Next, the printed circuit board A and the printed circuit board B are bonded so that conduction is not hindered. Usually, this is performed using an adhesive sheet. The adhesive sheet is a double-sided adhesive sheet, and can be adhered to the surface to be adhered by sandwiching the adhesive sheet and heat-pressing. Reference numeral 5 denotes an adhesive sheet, which is temporarily bonded to a printed board. Usually, it is temporarily bonded to the printed circuit board B provided with the through-hole. Since the adhesive sheet has tackiness as described above, temporary bonding is easy.
At this time, the conductive portions 6 of the printed boards A and B of the adhesive sheet
The portions corresponding to are subjected to processing such as drilling so as not to hinder conduction. Next, a portion corresponding to the space 4 is opened. This perforation may be performed before the temporary bonding as in the perforation of the conduction portion 6. In this case, it may be temporarily bonded to the printed circuit board A. Then, the other printed circuit board is positioned and superimposed and temporarily bonded, completely bonded by hot pressing, and processed into a product shape to obtain the multilayer printed circuit board of the present invention.

In FIG. 1, a through portion is formed only on the substrate B. However, if the position is shifted, a through portion can be provided on both the substrates A and B to mount components. In this case, the adhesive sheet may be temporarily bonded to either of the substrates A and B. The above is the case where the adhesive sheet is used, but the adhesive sheet is not necessarily used, and the bonding may be performed with a normal adhesive. In short, it is sufficient to bond the portions corresponding to the conductive portion 6 and the through portion 7 by masking or the like so that the adhesive is not applied.

Although the example shown in FIG. 1 is a case where two substrates are overlapped, three or more substrates may be overlapped. In this case, usually, all the substrates are temporarily bonded and then completely bonded. Also, since the substrate located in the middle is closed by the upper and lower substrates, the components need to be mounted before bonding. FIG. 2 shows an example in which three components are stacked, a through portion is provided in an intermediate substrate, and a component 7 is mounted. Further, if necessary, after the components are mounted, the outer penetrating portion 4 may be covered with an ink resin paste, a metal paste, a film, or the like.

[0009]

The multilayer printed circuit board of the present invention and the method of manufacturing the same have the following excellent effects. 1. Since the components can be mounted in the space in the printed board, the board can be made almost flat, and it is easy to reduce the thickness, and it can be suitably used for thin devices. In some cases, it is possible to mount all the components inside the board so that the components do not appear outside. 2. The number of mounted components can be increased. 3. Since the printed circuit boards to be superimposed are ones whose circuits have been completed in advance, laser processing and copper plating are not required, and the process is simplified. 4. Since the printed boards to be stacked are separately formed and bonded, partial conduction can be achieved. 5. If the penetrating portion is closed with an ink resin paste or the like, noise or the like may be prevented in some cases.

[Brief description of the drawings]

FIG. 1 is a diagram showing a cross section of each element constituting a multilayer printed board of the present invention.

FIG. 2 is a diagram showing a cross section of a multilayer printed circuit board according to the present invention.

[Explanation of symbols]

 2 Printed circuit board A 3 Printed circuit board B 4 Space part 5 Adhesive sheet 6 Conducting part

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5E346 AA06 AA12 AA15 AA22 AA32 AA43 AA51 CC02 DD02 FF01 FF45 GG15 GG28 HH24

Claims (3)

[Claims] 1. A multilayer printed circuit board having two or more printed circuit boards on which circuits are formed, and having at least one through-hole as a space in which components are stored. 2. A multi-layer print wherein a circuit is formed on each of them, and at least one of them has two or more printed circuit boards having a penetrating portion which is a space for accommodating parts superimposed and bonded. Substrate manufacturing method. 3. An adhesive sheet having a hole for ensuring conduction between the two or more printed circuit boards is temporarily bonded to one surface between the substrates, and then the through-hole is attached to the adhesive sheet. Or a temporary bonding of an adhesive sheet having a hole for securing conduction between the two and a hole corresponding to the penetrating portion, and laminating and bonding these substrates. A method for manufacturing a multilayer printed circuit board according to claim 2.