Abstract: A multilayer wiring board has a central wiring layer disposed in the center of an odd number of wiring layers, insulating layers and wiring layers disposed above and below the central wiring layer, respectively, an interlayer connections having cross-sectionally trapezoidal shapes and penetrating the insulating layers to establish interlayer connection between the wiring layers. The interlayer connection is disposed to connect to a portion below the central wiring layer. The interlayer connection is disposed to connect to a portion above the central wiring layer. The directions of tapers of the cross-sectionally trapezoidal shapes of the interlayer connections are identical.

Abstract: A multilayer wiring board 1 has a central wiring layer 10 disposed in the center of an odd number of wiring layers, insulating layers 11, 13, 15, 17 and wiring layers 12, 14, 16, 18 disposed above and below the central wiring layer 10, respectively, an interlayer connections 20, 21 having cross-sectionally trapezoidal shapes and penetrating the insulating layers 11, 13 to establish interlayer connection between the wiring layers 10, 12, 14. The interlayer connection 20 is disposed to connect to a portion below the central wiring layer 10. The interlayer connection 21 is disposed to connect to a portion above the central wiring layer 10. The directions of tapers of the cross-sectionally trapezoidal shapes of the interlayer connections 20, 21 are identical.