Multi-layer wiring board and method of manufacturing the same

1. A multi-layer wiring board without a core substrate, comprising:

a multi-layer laminated structure which is formed by alternately laminating a plurality of wiring layers and a plurality of insulating layers;

a plurality of first terminals which are provided on a front surface of the multi-layer laminated structure and on which a semiconductor integrated circuit device is to be mounted;

a plurality of second terminals which are provided on a rear surface of the multi-layer laminated structure opposite to the front surface and which are to be electrically connected to another board;

a solder resist which is formed to cover the rear surface and which comprises a plurality of solder resist openings formed at positions corresponding to positions of the second terminals;

a reinforcing plate which is made of a non-metal material and which comprises a plurality of reinforcing plate openings formed at positions corresponding to the positions of the second terminals; and

an adhesive layer which is interposed between the solder resist and the reinforcing plate to fix the reinforcing plate to the solder resist in a surface contact state and which comprises a plurality of adhesive layer openings formed at positions corresponding to the position of the second terminals,

wherein a diameter of the solder resist openings and a diameter of the reinforcing plate openings are smaller than that of the adhesive layer openings.

2. The multi-layer wiring board according to claim 1 ,

wherein the diameter of the reinforcing plate openings is smaller than that of the solder resist openings.

3. The multi-layer wiring board according to claim 1 ,

wherein the reinforcing plate is mainly formed of a synthetic resin, and

the adhesive layer is formed of a hardened material of a thermosetting resin.

4. The multi-layer wiring board according to claim 1 ,

wherein solder bumps or terminal pins are provided on a corresponding one of the second terminals.

5. The multi-layer wiring board according to claim 1 ,

wherein the diameter of the solder resist openings is smaller than that of the adhesive layer openings by 50 μm or more.

6. The multi-layer wiring board according to claim 1 ,

wherein the diameter of the reinforcing plate openings is reduced from a non-adhered surface to an adhered surface of the reinforcing plate.

7. A method of manufacturing a multi-layer wiring board, the method comprising:

(a) providing a multi-layer laminated structure which is formed by alternately laminating a plurality of wiring layers and a plurality of insulating layers, wherein a plurality of first terminals are provided on a front surface of the multi-layer laminated structure, and a plurality of second terminals are provided on a rear surface of the multi-layer laminated structure opposite to the front surface;

(b) forming a solder resist to cover the rear surface of the multi-layer laminated structure;

(c) forming a plurality of solder resist openings in the solder resist such that the solder resist openings are formed at positions corresponding to positions of the second terminals;

(d) providing a reinforcing plate which is made of a non-metal material and has a plurality of reinforcing plate openings formed therein, wherein an adhesive layer in non-hardened state is provided on one surface of the reinforcing plate, and the adhesive layer has a plurality of adhesive layer openings formed at positions corresponding to the positions of the reinforcing plate openings, and wherein a diameter of the solder resist openings and a diameter of the reinforcing plate openings are set to be smaller than that of the adhesive layer openings;

(e) fixing the reinforcing plate to the solder resist in a surface contact state using the adhesive layer, such that each of the reinforcing plate openings is opposed to a corresponding one of the solder resist openings; and

(f) hardening the adhesive layer in the non-hardened state at a temperature that is lower than a solder melting temperature.