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Koichiro ISHIBASHI Hisayuki HIGUCHI Toshinobu SHIMBO Kunio UCHIYAMA Kenji SHIOZAWA Naotaka HASHIMOTO Shuji IKEDA
There are various kinds of analog CMOS circuits in microprocessors. IOs, clock distribution circuits including PLL, memories are the main analog circuits. The circuit techniques to achieve low power dissipation combined with high performance in newest prototype chip in the Super H RISC engines are described. A TLB delay can be decreased by using a CAM with a differential amplifier to generate the match signal. The accelerator circuit also helps to speed up the TLB circuit, enabling single-cycle operation. A fabricated 96- mm 2 test chip with the super H architecture using 0. 35-µm four metal CMOS technology is capable of 167-MHz operation at 300 Dhrystone MIPS with 2. 0-W power dissipation.
Koichiro ISHIBASHI Kunihiro KOMIYAJI Sadayuki MORITA Toshiro AOTO Shuji IKEDA Kyoichiro ASAYAMA Atsuyosi KOIKE Toshiaki YAMANAKA Naotaka HASHIMOTO Haruhito IIDA Fumio KOJIMA Koichi MOTOHASHI Katsuro SASAKI
A 16-Mb CMOS SRAM using 0.4-µm CMOS technology has been developed. This SRAM features common-centroid-geometry (CCG) layout sense amplifiers which shorten the access time by 2.4 ns. A flexible redundancy technique achieves high efficiency without any access penalty. A memory cell with stacked capacitors is fabricated for high soft-error immunity. A 16-Mb SRAM with a chip size of 215 mm2 is fabricated and an address access time of 12.5 ns has been achieved.
We have improved the mechanical reliability of deep-submicron semiconductor devices by applying a simulation technique. Typical kinds of damages that reduce the reliability are dislocations in silicon substrates, delamination or cracking of thin films, and deterioration of electronic characteristics of devices. The mechanical stress that develops in device structures is caused by not only mismatches in thermal expansion coefficients among thin film materials but also intrinsic stress of thin films such as poly-silicon and silicides. Fine patterning by dry etching makes sharp edges and they also cause stress concentration and thus high stress. The manufacturing processes in which stress mainly develops are isolation, gate formation, and interconnect formation. We have developed methods for reducing the stress in each of the above-mentioned process. This stress reduction is very effective for highly reliable manufacturing. Finally, we clarify the effect of the residual stress in transistor structures on shift in the electronic characteristics of MOS transistors.