| 摘要 |
PURPOSE:To improve a via-hole in fill density of conductor and electrical conduction by a method wherein conductor composed of two types of conductor particles, one large in grain diameter and the other small, is filled into a via- hole (small through-hole) in this sequence. CONSTITUTION:When a conductor 4 is filled into a via-hole 3, copper powder 10 small in grain diameter is filled into the hole 3 first with a squeegee. At this point, as the copper powder 10 is small in grain diameter, it is liable to cohere to induce voids. In succession, copper powder 11 large in grain diameter is filled into the via-hole S. As the copper powder 11 is large in grain diameter, it is hard to be filled into the via-hole 3 as compared with the copper powder 10, so that the copper powder 11 is filled by a larger filling power as compared with the copper powder 10. In result, the small copper powder 10 is pressed by the large copper powder 11 to eliminate voids (E), so that a conductor 4 is enhanced in fill density and consequently a via 9 is improved in electrical conduction, and therefore a multilayered ceramic board is improved in reliability. |
