JPH0645763A - Printed wiring board - Google Patents

Abstract

PURPOSE:To obtain a printed wiring board mounted with electronic parts high in mounting density by a method wherein semiconductor chips are built in holes provided inside the board. CONSTITUTION:A printed wiring board is composed of two outer boards 2 and an inner board 1 sandwiched in between the two outer boards 2 and equipped with circuit wiring layers 3 each provided onto the surface of the wiring board and between the boards. A hole 7 is provided to the inner board 1 at a prescribed position, and a pad and a wiring used for mounting an IC chip 6 are formed on the circuit wiring layer 3 exposed at the hole 7. The IC chip 6 is mounted on the circuit wiring layer 3 through the intermediary of bumps 5. Electronic parts 4 are formed on the surfaces of the printed wiring board at prescribed positions. As mentioned above, an IC is mounted inside the hole 7 provided to the inner board 1, so that elements mounted on a printed wiring board can be enhanced in number per unit area.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printed wiring board, and more particularly to a printed wiring board capable of high-density mounting.

[0002]

2. Description of the Related Art As shown in FIG. 3, a conventional printed wiring board includes an inner layer substrate 1 and an outer layer substrate 2 made of an insulating material such as glass epoxy or a polyimide material, and a circuit wiring layer 3 mainly made of copper material. It is configured. On the circuit wiring layer 3 formed on the outer side of the outer layer substrate 2, that is, on the surface of the printed wiring board, pads for mounting electronic components 4 and circuits for electrically connecting the electronic components 4 are formed. There is. Further, the circuit wiring layer 3 formed between the inner layer substrate 1 and the outer layer substrate 2 is provided with circuits that cannot be formed on the surface of the printed wiring board.

In this conventional printed wiring board, the electronic components are mounted only on the surface. Therefore, in order to increase the mounting density, the electronic components can be downsized and the mounting technique for the multi-pin narrow-pitch components. There is a problem that it is difficult to dramatically increase the packaging density at present.

An object of the present invention is to provide a printed wiring board having a high mounting density of electronic components.

[0004]

DISCLOSURE OF THE INVENTION The present invention provides a printed wiring board on which a plurality of electronic components are mounted on at least one of the front surface and the back surface, and a hole is provided inside the printed wiring board. Built-in semiconductor chip.

[0005]

Embodiments of the present invention will now be described with reference to the drawings.

FIG. 1 is a sectional view of a first embodiment of the present invention.

As shown in FIG. 1, the first embodiment comprises an inner layer substrate 1 and two outer layer substrates 2 sandwiching the inner layer substrate 1, and has a circuit wiring layer 3 on the surface and between layers. . Holes 7 are provided at predetermined positions in the inner layer substrate 1, and although not shown, pads and wirings for mounting the IC chip 6 are formed on the circuit wiring layer 3 exposed in the holes 7 portion. There is.
The IC chip 6 is mounted on the circuit wiring layer 3 via the bumps 5. The electronic component 4 is also mounted on the surface of the printed wiring board at a predetermined position.

The IC chip 6 in the inner layer substrate 1 can be mounted by bumps 5, electrical connection by wire bonding or mounting by TCP (tape carrier package).

As described above, by mounting the IC chip 6 in the hole 7 of the inner layer substrate 1, the number of elements mounted per unit area is increased as compared with the conventional printed wiring board.

FIG. 2 is a sectional view of the second embodiment of the present invention.

The constituent elements of the second embodiment are almost the same as those of the first embodiment, as shown in FIG. 2, except that holes are provided in the outer layer substrate 2 to mount the IC chip 6, and In this example, the inside of the hole is sealed with the sealing material 8.

In the first embodiment, it is necessary to mount the IC chip 6 during the manufacturing process of the printed wiring board, but in the printed wiring board of the second embodiment, holes are provided on the surface, so that the printed wiring board is provided. There is an advantage that the IC chip 6 can be mounted like other electronic components 4 after the manufacture of the plate is completed.

[0013]

As described above, the printed wiring board of the present invention has the effect that the mounting density can be increased by incorporating the IC chip therein.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a first embodiment of the present invention.

FIG. 2 is a sectional view of a second embodiment of the present invention.

FIG. 3 is a cross-sectional view of an example of a conventional printed wiring board.

[Explanation of symbols]

 1 Inner Layer Substrate 2 Outer Layer Substrate 3 Circuit Wiring Layer 4 Electronic Component 5 Bump 6 IC Chip 7 Hole 8 Sealant

Claims (1)

[Claims] 1. A printed wiring board having a plurality of electronic components mounted on at least one of a front surface and a back surface, wherein a hole is provided inside and a semiconductor chip is built in the hole. And printed wiring board.