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

随着超大规模集成电路微加工技术的进步，由微处理器和大存储器组成的集成电子系统可以在单个芯片上实现。这些“片上系统”是实现手机、数码相机等小型、低功耗、高性能系统的关键部件。由于掩模成本的原因，“片上系统”的初始开发成本变得昂贵。最新的“片上系统”的掩膜成本超过了100万美元。对于小批量生产的大规模集成电路来说，这一成本是一个关键问题，而芯片成本的大部分取决于“片上系统”的掩模成本，其全寿命产量小于1万个。因此，为了实现低成本的“片上系统”，必须开发降低掩模成本的新技术。我们采用EB直写技术作为光刻工具。EB直写是一种无掩码的技术，因此它没有掩码成本。然而，EB直写的吞吐量远低于光刻。即使是小批量的大规模集成电路生产，也必须缩短EB直接写入时间。采用字符投影EB直写技术，提高了数据吞吐量。本研究开发了三个关键技术。首先，开发了基于字符投影光刻的接近效果校正技术，以提高图案精度。其次，我们提出了新颖的“字符构建标准单元”设计方法，实现了高吞吐量的EB直写。最后，研究了一种适合EB直写的可编程逻辑体系结构。通过以上三个方面的研究，我们推动了小批量“片上系统”的低成本技术。

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".