| 摘要 |
PURPOSE: To provide an electronic component mounting board which can improve the efficiency of a wiring while the whole thickness of the board is prevented from being increased. CONSTITUTION: A first group of pads are formed on the outermost layer of a build-up layer B1 formed by laminating alternately interlayer insulating layers 8a and 8b and internal layer conductor layers 9a and 9b. The layers 8a and 8b of the layer B1 consist of a photosensitive resin, which is hardly soluble to an acid or an oxidizing agent, and heat-resistant resin particles, which are soluble to the acid and the oxidizing agent. A wiring is always provided in the forward direction and centrifugally toward the outer peripheral parts of a board while the layer 9a linking the pads 12, which constitute the first group of the pads, with each other and an internal layer conductor layer 9a linking pads 13, which constitute a second group of the pads 13, with each other are respectively connected with the layers 8a and 8b and interlayer insulating layers 8a and 8b through via holes 11 formed in the layers 8a and 8b. |
