Printed wiring board
US8110749B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 20, 2009 |
| Grant date | Feb 7, 2012 |
| Priority date | — |
| Expiry date | Feb 17, 2030 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH05K2201/09809
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Large-sized through holes are formed in a core layer of a printed wiring board. Large-sized vias are formed in the shape of a cylinder along the inward wall surfaces of the large-sized through holes located within a specific area. A filling material fills the inner space of the large-sized via. A small-sized through hole penetrates through the corresponding filling material along the longitudinal axis of the small-sized through hole. A small-sized via is formed in the shape of a cylinder along the inward wall surface of the small-sized through hole. The filling material and the core layer are uniformly distributed within the specific area in the in-plane direction of the core substrate. This results in suppression of uneven distribution of thermal stress in the core layer in the in-plane direction of the core layer.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.