| 摘要 |
PURPOSE: To make the ground potential of each layer equal to zero, by using a through hole provided with a step-difference to be connected with an inner layer pattern. CONSTITUTION: The title multilayered printed board 9 consists of the following; a surface layer 1, a ground layer 2, a power supply layer 3, and a back layer 4. Plating layers 5 are formed on circuit patterns (copper foils) on the surface layer 1 and the back layer 4. A prepared hole whose diameter is different every layers of the board 9 is formed. A step-difference 6 is formed on the back side of the copper foil part of, e.g. the ground layer 2. The wall surface of the prepared hole is plated with conductive material. Thus the title through hole 16 is formed which mutually connects the circuit patterns on necessary layers. A pipe 7 of conductor whose shape is nearly equal to that of the prepared hole is contained. |
