Method for producing multi-layer printed wiring boards having blind vias

在铜箔表面电沉积一种不溶于碱性蚀刻溶液的耐碱金属，然后在该表面上施涂热固性树脂，使其半固化，得到经涂覆的铜箔。将经涂覆的铜箔与其一面或两面具有线路的内层板的一面或两面粘合。再通过碱性蚀刻除去该层压板一面上的铜箔，同时有选择地留下耐碱金属层。用激光束在耐碱金属层和热固性树脂层中同时形成通孔。使用上述方法，可以用激光容易地形成多层印刷线路板的通孔，并且能提高由镀敷铜制得的外部线路和绝缘树脂间的粘合力。 An alkaline refractory metal (2) which is insoluble in alkaline etching solutions, is electrodeposited on the surface of copper foil (1), then a thermosetting resin (3) is applied to the surface and semi-cured to obtain a coated copper foil. The coated copper foil is bonded to one or both faces of an inner layer board (5) having wirings (4) on one or both of its faces. Then, the copper foil (1) on a surface of this laminate is removed by alkaline etching, while selectively leaving the alkaline refractory metal layer (2). A laser beam is used to form via holes (6) in both the alkaline refractory metal layer and the thermosetting resin layer simultaneously. With the above method, via holes of the multi-layered printed wiring board can be easily formed using a laser, and adhesion between the outer wirings (8) made from the plated copper (7) and the insulating resin (3) is improved.