CIRCUIT BOARD FABRICATION LEADING TO INCREASED CAPACITY

摘要

Printed circuit boards having a plurality of circuit layers are produced using a specific processing sequence. A copper-clad substrate (31) is first patterned in a desired configuration to produce the first layer of the printed circuit board. The patterned metallization (32) is then covered with a specifically formulated energy sensitive material (Fig. 3B). The energy sensitive material is delineated in a desired pattern and developed to uncover portions of the underlying metallization pattern. The entire substrate is blanket-cured to produce a rigid layer having openings in appropriate places. The openings are metallized (34, 35) and a second copper pattern is produced on the cured polymer by conventional metallization and lithographic techniques. If desired, the process is repeated until a suitable number of copper patterned levels are obtained.