Low-Cost and Low-Power LSI design Methodology optimized for Electron Beam Direct Writing Technique with Merged Memory Circuit

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Integrated electronic system composed of microprocessors and large memories can be realized as a single chip owing to the progress of micro-fabrication technology of VLSI. These "System On a Chip" are key parts which realize small, low-power, and high-performance system such as mobile phones and digital still cameras.Initial development cost of "System On a Chip" become expensive due to the mask cost. The mask cost for the latest "System On a Chip" becomes more than 1 million dollars. This cost is a critical issue for small-production volume LSI, and the most of the chip cost depends upon the mask cost for "System On a Chip" whose whole-life production volume is less than 10 thousand. Therefore, the new technologies reducing mask cost must be developed for the low-cost "System On a Chip".We adopted EB direct-writing technique as a lithography tool. EB direct-writing is the mask-less technique, then it is free from mask-cost. However, the throughput of EB direct-writing is much lower than that of photo-lithography. Even for the small-volume LSI production, EB direct-writing time have to be shortened. Character-projection EB direct-writing technique is applied in order to increase the throughput.Three key technologies are developed in this study. First, proximity-effect-correction technique using character projection lithography is developed for high-patterning accuracy. Secondly, we proposed novel "Character-build standard cell" design methodology, which realize high throughput EB direct writing. Lastly, via-programmable logic architecture which is' suitable for EB direct-writing is examined. Using these three studies mentioned above, we promote the low-cost technology for small-production volume "System On a Chip".