Separable cells having wiring channels for routing signals between surrounding cells
US5638288A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Aug 24, 1994 |
| Grant date | Jun 10, 1997 |
| Priority date | — |
| Expiry date | Aug 24, 2014 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10D84/90
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
On integrated circuit designs employing large, pre-defined circuit blocks, chip area utilization and signal routing is improved by permitting signals between circuit blocks surrounding (e.g., on opposite sides of) a large circuit block (megacell) to physically pass through the megacell. The megacell is laid out so that a "parting line" is defined through the megacell. Circuits within the megacell are laid out so that no circuit "straddles" the parting line. The megacell can then be split or stretched about the parting line to create a wiring channel. The wiring channel is used for routing signals from the surrounding cells (circuit blocks) through the large circuit block (megacell). Signals between the separated portions of the stretched or split megacell on opposite sides of the parting line may be routed in one metal layer, while connections of surrounding cells through the megacell may be routed in another metal layer. A maximum split or stretch distance is defined for which the megacell performance specifications (e.g., timing constraints) will be met. A plurality of surrounding cells may be interconnected by routing their signals in stacked wiring layers. The megacell may be s…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.