| 摘要 |
PURPOSE: To reduce the amount of exudation of an insulation adhesion material by overlapping a film-shaped material drilled on an inner-layer circuit substrate and further overlapping a cushion material on it. CONSTITUTION: A film-shaped material drilled on an inner-layer circuit substrate is overlapped so that a circuit substrate and an insulation adhesion layer are in contact, further a cushion material is overlapped on it to achieve flow behavior due to heating, and heating and pressurization are performed for lamination in one piece, thus causing the cushion material to flow from a connection part where a sheet-shaped reinforcing material is drilled to block a hole part and hence reducing the amount of exudation of the insulation adhesion material and hence reducing the hole diameter for connecting layers. Also, since the amount of flow of the cushion material is small at a part where the sheet-shaped reinforcing material is not drilled, the recess and projecting parts of the inner- layer copper foil can be flattened by the insulation adhesion material and improving surface smoothness. |
