Browse Prior Art Database

High Density High Performance I/2/L Cell

IP.com Disclosure Number: IPCOM000086891D
Original Publication Date: 1976-Nov-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 2 page(s) / 90K

Publishing Venue

IBM

Related People

Chang, CS: AUTHOR [+4]

Abstract

The cell shown in Figs. 1 and 1A provides increased wirability (therefore, higher density) and improved circuit performance over conventional I/2/L. The increased wirability is achieved by enlarging the NPN base region and providing multiple base contacts. As a result, extra wiring channels exist within the cell area to provide more degree of freedom for cell selecting the LSTs (logical service terminals for connecting circuit input and output). Circuit performance is improved because the new cell has one less output location (four instead of five for fan-out = 4). Therefore, the device upward beta can be maximized.

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High Density High Performance I/2/L Cell

The cell shown in Figs. 1 and 1A provides increased wirability (therefore, higher density) and improved circuit performance over conventional I/2/L. The increased wirability is achieved by enlarging the NPN base region and providing multiple base contacts. As a result, extra wiring channels exist within the cell area to provide more degree of freedom for cell selecting the LSTs (logical service terminals for connecting circuit input and output). Circuit performance is improved because the new cell has one less output location (four instead of five for fan-out = 4). Therefore, the device upward beta can be maximized. Placing the NPN base contact close to the injector and using multiple base contact reduces the PNP collector-to-base resistance, as well as the NPN extrinsic base resistance, yielding better device and circuit performance.

This cell provides more LSTs. Thus when used as a master-slice design, personalization can be accomplished at first metal rather than at emitter diffusion.

To further improve the wirability, an additional row of LSTs can be added to the outside of the input base contact or the three-base contacts can be changed to four-base contacts, as shown in Figs. 2 and 2A.

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