| 摘要 |
1,228,651. Printed circuits. TELEFUNKEN PATENT VERWERTUNGS G.m.b.H. 18 June, 1968 [28 June, 1967], No. 28876/68. Heading H1R. A method of manufacturing a multilayer printed circuit board having at least four layers of printed circuitry comprises the steps of: making similar holes in corresponding positions in a plurality of insulating support plates 1 having metal-clad surfaces; depositing metal on the surfaces of the holes to line the holes; forming required printed circuits in the metalclad surfaces which when the pack is assembled form internal surfaces of the pack; applying adhesive layers 11 to the surfaces of the plates 1, stacking the plates 1 so that the holes therein are aligned and allowing the adhesive to set; removing any surplus adhesive 12 from the holes; depositing another coating of metal on the surfaces of the aligned holes over the original lining to form a through connection through the pack; and forming required circuit patterns from the two metal clad surfaces constituting the outer surfaces of the pack. Each support plate 1 is made of larger dimensions than the finished article so as to leave a margin and after stacking the plates guide holes are drilled simultaneously through all the margins of the stack. The plates are thus held in register by guide pins passing through the guide holes during drilling of the holes to be plated through the pack. The plates are then disassembled for the plating through and formation of the printed circuits. A mounting jig having pins 7 is then employed for the permanent stacking and insulating sheets 8 may be inserted between neighbouring plates. The circuit patterns may be reinforced by an electroless deposition of tin. |
