| A physical synthesis to islands of cells with the same diffusion width |
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| Authors |
| | Ryzhenko N.V. |
| Date of publication |
| | 2010 |
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| Abstract |
| | As feature sizes shrink without a corresponding change in lithography wavelength, feature patterning becomes ever more challenging. While lithography experts see ways to keep up with Moore’s law at least in the short term, these techniques introduce new costs due to multi-mask exposures or more time consuming OPC calculations. Here we look at complementary techniques - how to generate layouts that are more regular to begin with and thus can conceivably obviate or delay the need to switch over to these more expensive patterning
approaches.
We begin by defining a regular diffusion substrate - all diffusion and poly are preprinted.
Connections are specialized using poly and diffusion contacts and the metal/via stack. Adjacent transistors either share diffusions (usually a power rail) or are electrically isolated using the intervening device with its gate tied to a rail (gate isolation.)
We then show the power/performance cost of using a fabric with equal diffusion sizes for all
devices and develop ways to get around this by allowing multiple diffusion widths but then
clustering cells with the same diffusions sizes together. Sophisticated flows built on top of LRbased sizing tools are described to reduce this cost from fifteen to only a few percent. Moving
cells from their natural position in order to achieve a good diffusion clustering often increases wire length and introduces routing congestion. Flows to alleviate this are described as well. |
| Keywords |
| | Physical Synthesis, Sizing, Placement, Regular Fabric |
| Library reference |
| | Ryzhenko N.V. A physical synthesis to islands of cells with the same diffusion width // Problems of Perspective Micro- and Nanoelectronic Systems Development - 2010. Proceedings / edited by A. Stempkovsky, Moscow, IPPM RAS, 2010. P. 178-183. |
| URL of paper |
| | http://www.mes-conference.ru/data/year2010/papers/m10-278-15301.pdf |
