To provide a multilayer printed board whose 1st layer and 4th layer and n-th layer and (n-3)th layer can be connected with high accuracy and in a small number of steps, and a method thereof.
In a multilayer wiring board 1 having (n) layers of four or more, the 1st layer 3 and the 2nd layer 5, the 1st layer 3 and the 3rd layer 9, the 3rd layer 9 and the 4th layer 13, the 1st layer 3 and the 4th layer 13, the n-th layer 19 and the (n-1)th layer 21, the n-th layer 19 and the (n-2)th layer 25, the (n-2)th layer 25 and the (n-3)th layer 29, and the n-th layer 19 and the (n-3)th layer 29 are connected, respectively. Holes 37 of 30 μm in diameter are made in the insulating materials 35 between the respective layers of; the 1st layer 3 and the 2nd layer 5; the 3rd layer 9 and the 4th layer 13; the n-th layer 19 and the (n-1)th layer 21; and the (n-2)th layer 25 and the (n-3)th layer 29, and are filled with copper plating 39 to connect the 1st layer 3 and the 3rd layer 9, the 3rd layer 9 and the 4th layer 13, the n-th layer 19 and the (n-1)th layer 21, and the (n-2)th layer 25 and the (n-3)th layer 29.
Next Patent: MULTILAYER WIRING BOARD