| 摘要 |
<p>Printed circuit plates are produced in stages in which an insulating base plate with a printed circuit pattern in one plane is made and the exposed printed circuit pattern and the exposed base plate are coated with a permanent mask, after which a thin metal layer is applied to its surface. The metal layer is coated with an insulating, temporarily masking, layer. A hole is made through the plate and thin layer of metal is deposited around all the exposed walls of the holes. Extra metal is electroplated on the thin metal coating, after which the temporarily masking layer and the thin metal layer are removed from the surface of the permanent mask, which is then exposed.</p> |
