| 摘要 |
PURPOSE:To form via holes within a short time by a method wherein a green sheet is coated with a resin paste to be formed into a thick film and then dried up to impose a strain on the green sheet for removing the green sheet in the strain. CONSTITUTION:The upper and lower surfaces above the via hole forming positions of a ceramic made green sheet 1 is coated with a resin paste 2 such as methyl cellulose etc. to be formed into a thick film. Next, the green sheet 1 is dried up at high temperature. At this time, due to the larger thermal contraction coefficient of the resin paste 2 than that of the green sheet 1, the cracks 3 passing through the upper and lower surface of the green sheet 1 are caused on the periphery of the resin paste 2. Later, a mild oscillation or mild shock is administered to the green sheet 1 or the resin paste 2 to remove the green sheet 1 inside the crack 3 for the formation of the via holes 1b. Through these procedures, the plural via holes 1b can be formed at once by coating and contracting the resin paste 2 thereby enabling the formation time of the via holes 1b to be cut down. |
