Wiring board and electronic component device
A wiring board adapted for mounting an electronic component has the form of a structure in which a plurality of wiring layers are stacked one on top of another with an insulating layer interposed therebetween and are interconnected through via holes formed in the insulating layers, respectively. A plurality of openings are formed through the structure in a region where a wiring is not formed, extending through the structure in a thickness direction thereof. Further, solder resist layers are formed on the outermost wiring layers, respectively, and exposing pad portions defined in desired locations in the outermost wiring layers.
1. A wiring board adapted for mounting an electronic component, comprising:
a plurality of stacked wiring layers having an insulating layer interposed therebetween;
a wiring forming region defined by a portion corresponding to a region where the electronic component is mounted; and
a peripheral region around the wiring forming region,
wherein, in the wiring forming region, the plurality of wiring layers are interconnected through a via hole formed in the insulating layer, and outermost wiring layers of the plurality of stacked wiring layers are provided on both surfaces of the wiring board, and wherein,
in the peripheral region, a plurality of openings are formed in the insulating layer in a portion where a wiring of the wiring layer is not formed, with each opening being defined entirely by the insulating layer and being unfilled therein, and
the plurality of openings extending from one outermost wiring layer to the other outermost wiring layer of the plurality of wiring layers of the wiring board in a thickness direction thereof.
2. The wiring board according to claim 1 , wherein the plurality of openings are formed in such an arrangement as to cut off propagation of a stress being through the wiring board, the stress being induced according to a difference in the coefficient of thermal expansion between a thermosetting material and the wiring board at the interface therebetween when the electronic component is mounted on the wiring board using the thermosetting material.
3. The wiring board according to claim 1 , further comprising solder resist layers formed on the outermost wiring layers, respectively, and exposing pad portions defined in the outermost wiring layers and exposing the plurality of openings.
4. An electronic component device comprising:
the wiring board according to claim 1 ; and
an electronic component mounted on the wiring board with a thermosetting material interposed in therebetween,
wherein the plurality of openings are filled with part of the thermosetting material.
5. The wiring board according to claim 1 , further comprising solder resist layers formed on the outermost wiring layers, respectively, and exposing pad portions defined in the outermost wiring layers and covering the plurality of openings.
6. The wiring board according to claim 1 , wherein the plurality of openings are formed in each diagonal direction in the peripheral region.
7. The wiring board according to claim 1 , wherein each of the plurality of openings is provided in the form of a through hole.
8. The wiring board according to claim 1 , wherein each of the plurality of openings is provided in the form of a slit.