| 摘要 |
PURPOSE:To realize a low permittivity and to attain the constitution comprising a high-density pattern of a multilayer interconnection layer and a stable accuracy in size by forming an air layer between laminated intermediate boards and using a ceramic substrate provided with via holes filled with a conductor as a core member of the intermediate board. CONSTITUTION:Intermediate boards 1A and 1B are composed of ceramic substrates 2A and 2B, multilayer interconnection layers 3Aa, 3Ab, 3Ba and 3Bb which are formed on both sides of said ceramic substrates. The ceramic substrates 2A and 2B comprise via holes 4A and 4B filled with conductors and the multilayer interconnection layers 3Aa, 3Ab, 3Ba and 3Bb are composed of signal lines 12, 22, 32 and 42, and connecting pads 13 and 43. Further, self- alignment pads 16, 26, 36 and 46 for alignment at the time of layer-lamination are arranged. The connecting pads and the self-alignment pads are made higher than the signal lines and there is produced an air layer 5 between the intermediate boards 1A and 1B. |
