Improvement in Computational Accuracy of Output Transition Time Variation Considering Threshold Voltage Variations

Takaaki OKUMURA; Atsushi KUROKAWA; Hiroo MASUDA; Toshiki KANAMOTO; Masanori HASHIMOTO; Hiroshi TAKAFUJI; Hidenari NAKASHIMA; Nobuto ONO; Tsuyoshi SAKATA; Takashi SATO

doi:10.1587/transfun.E92.A.990

Special Section on Advanced Technologies Emerging Mainly from the 21st Workshop on Circuits and Systems in Karuizawa

Improvement in Computational Accuracy of Output Transition Time Variation Considering Threshold Voltage Variations

Takaaki OKUMURA, Atsushi KUROKAWA, Hiroo MASUDA, Toshiki KANAMOTO, Masanori HASHIMOTO, Hiroshi TAKAFUJI, Hidenari NAKASHIMA, Nobuto ONO, Tsuyoshi SAKATA, Takashi SATO

Author information

Takaaki OKUMURA
Semiconductor Technology Academic Research Center
Atsushi KUROKAWA
SANYO Semiconductor Co., Ltd.
Hiroo MASUDA
Renesas Technology Corp.
Toshiki KANAMOTO
Renesas Technology Corp.
Masanori HASHIMOTO
Osaka University
Hiroshi TAKAFUJI
RICOH Company Ltd.
Hidenari NAKASHIMA
NEC Electronics Corp.
Nobuto ONO
Jedat Inc.
Tsuyoshi SAKATA
Fujitsu Microelectronics Ltd.
Takashi SATO
Tokyo Institute of Technology

Keywords: SSTA, output, transition time, gate delay model, process variation

JOURNAL RESTRICTED ACCESS

2009 Volume E92.A Issue 4 Pages 990-997

DOI https://doi.org/10.1587/transfun.E92.A.990

Details

Abstract

Process variation is becoming a primal concern in timing closure of LSI (Large Scale Integrated Circuit) with the progress of process technology scaling. To overcome this problem, SSTA (Statistical Static Timing Analysis) has been intensively studied since it is expected to be one of the most efficient ways for performance estimation. In this paper, we study variation of output transition-time. We firstly clarify that the transition-time variation can not be expressed accurately by a conventional first-order sensitivity-based approach in the case that the input transition-time is slow and the output load is small. We secondly reveal quadratic dependence of the output transition-time to operating margin in voltage. We finally propose a procedure through which the estimation of output transition-time becomes continuously accurate in wide range of input transition-time and output load combinations.

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