Seal ring structure for IC containing integrated digital/RF/analog circuits and functions
US6492716B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 30, 2001 |
| Grant date | Dec 10, 2002 |
| Priority date | — |
| Expiry date | Apr 30, 2021 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L2924/3011
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
Embodiments of the present invention provide a seal ring which includes a plurality of cuts separating the seal ring into seal ring portions which are disposed adjacent to different circuits in the integrated circuit die. The cuts reduce the noise coupling among the different circuits through the seal ring. To further isolate the sensitive RF/analog circuits from the noise generated by the digital circuit, the seal ring may be electrically (for dc noise) isolated from the substrate. This is accomplished, for instance, by inserting a polysilicon layer and gate oxide between the seal ring and the substrate. In addition, an n-well/p-well capacitor may be formed in series with the gate oxide, for instance, by implanting an n-well below the polysilicon layer in a p-type substrate. In this way, the seal ring provides substantially reduced noise coupling among the circuits but still maintains an effective wall around the periphery of the die to protect the circuits against moisture and ionic contamination penetration.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.