| 摘要 |
On a surface of an insulating board (1), a front wiring pattern (2) is formed. On the rear surface of the insulating board (1), opposing the front wiring pattern (2), a rear wiring pattern (3) is formed in a shape which is substantially plane-symmetrical to the front wiring pattern (2). An opening (10) which penetrates the front wiring pattern (2) and the rear wiring pattern (3) is formed. At the inner wall of the opening (10), an electrically conductive layer (8C) is formed. Inside the opening (10), solder (11), for example, is placed to form an electrically conductive filling. As a result, the front wiring pattern (2) and the rear wiring pattern (3) are positively connected to each other electrically. Therefore, the current capacity and the heat capacity of the wiring patterns are increased, and the amount of generated heat is reduced. <IMAGE> <IMAGE> |
