| 摘要 |
PURPOSE: To prevent the occurrence of micro cracks in a metallic layer and an adhesion loss between a dielectric and a metal, by forming via holes in the dielectric layer by a laser abrasion method for controlling the laser energy in proportion to the thickness of the dielectric layer. CONSTITUTION: A first dielectric layer 209 coating a first conductive pattern layer 205 is bored by metal filled via holes 211 which are laser-abraded. A second conductive pattern layer 215 exists on the first dielectric layer 209. The second conductive pattern 215 is coated with a second dielectric layer 216 and the metal filling via holes 211 and 212 pass through the second dielectric layer. The metal via holes 211 and 212 form connection from the lower conductive pattern layer to a surface conductive pattern layer 218. Although laser energy is sufficient for forming the via holes in the dielectric, it is controlled in accordance with the thickness of the dielectric layer so that it does not become large for removing the part of the conductive pattern layer below the via holes. |
