PCB FOR USE OF RAM BUS

摘要

PURPOSE: A printed circuit board for use of RAM bus is provided, in which the insulation layer of the outermost layer of the PCB is formed of a thin pre-preg and one side copper clad laminate, to thereby prevent impedance errors caused by the thickness difference of the adhesive layer. CONSTITUTION: A PCB includes a plurality of two sides copper clad laminates(111,115) where a copper clad is etched so as to form circuits(103,105,112,113,116,117) at both sides of two sides copper clad laminates. Two sides copper clad laminates are adhered to each other through adhesive layers(107,109). Upper and lower two sides copper clad laminates(111,115) have adhesive layers(120,124) which are formed of a pre-preg. Adhesive layers have thickness smaller than that of adhesive layers(107,109) for adhering two sides copper clad laminates. One side copper clad laminates(122,126) having thickness smaller than that of two sides copper clad laminate, are deposited onto adhesive layers. One side copper clad laminates have copper clad only at the side which does not contact adhesive layers.