| 摘要 |
PURPOSE:To improve reliability in electrical continuity between a land on an inner-layer board and a land on an outer-layer board in a multilayer printed wiring board. CONSTITUTION:Connection holes 17, 26 and 32 are formed at lands 20, 28 and 32 in an inner-layer board 1, while contact holes 15, 24 and 30, and 17, 26 and 32 corresponding to the contact holes 17, 26 and 32 are formed in outer-layer boards 2 and 3. After the inner-layer board 1 and outer-layer boards 2 and 3 are bonded with an adhesive sheet 8, these contact holes are filled with a conductive paste 37. The contact holes 15, 24 and 30, and 16, 25 and 31 in the outer-layer boards 2 and 3 is made larger in diameter than the contact holes 17, 26 and 32 in the inner-layer board 1 so that an exposed area of the lands 20, 28 and 33 in the inner-layer board 1 is increased. In this way, the contact area between the lands 20, 28 and 33 and the conductive paste 37 is enlarged, and reliability in electric continuity can be improved. |
