| 摘要 |
<p>PROBLEM TO BE SOLVED: To improve connection reliability between a stack via and a conductor due to thermal stress.SOLUTION: A printed wiring board includes: a first build-up layer which has a first conductor layer formed on a first insulating layer, and a first via conductor penetrating the first insulating layer and connected to the first conductor layer; a second build-up layer which has a second insulating layer formed on the first build-up layer, a second conductor layer formed on the second insulating layer, and a second via conductor penetrating the second insulating layer and electrically connecting the first conductor layer and the second conductor layer; and a third build-up layer which has a third insulating layer formed on the second build-up layer, a third conductor layer formed on the third insulating layer, and a third via conductor penetrating the third insulating layer and electrically connecting the third conductor layer and the second conductor layer. The second insulating layer is thinner than the first insulating layer and the third insulating layer. The first via conductor, the second via conductor, and the third via conductor are laminated stepwise to form a stepped stack via structure.</p> |
