| 摘要 |
Circuit boards, useful in microwave frequency applications, are formed from a laminate consisting initially of an insulator sandwiched between a copper foil and an aluminum plate. The boards are provided with through-hole connections by means of a procedure which includes drilling through the board to form through-holes, anodizing all exposed surfaces of the aluminum, electroplating copper over all anodized aluminum surfaces, sodium or plasma etching to alter the surface of the walls of the holes in the insulator to allow them to be "wet", and electroless copper plating the entire board to form a continuous upper coating over the copper foil, the copper plate and the walls of the through-holes.
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