|
发表于 2007-9-7 12:34:44
|
显示全部楼层
FOREWORD
Among many great inventions made in the 20th century, electronic circuits,
which later evolved into integrated circuits, are probably the biggest, when
considering their contribution to human society. Entering the 21st century, the
importance of integrated circuits has increased even more. In fact, without the
help of integrated circuits, recent high-technology society with the internet,
cellular phone, car navigation, digital camera, and robot would never have
been realized. Nowadays, integrated circuits are indispensable for almost every
activity of our society.
One of the critical issues for the fabrication of integrated circuits has been
the precise design of the high-speed or high-frequency operation of circuits with
huge number of components. It is quite natural to predict the circuit operation
by computer calculation, and there have been three waves for this, at 15-year
intervals. The first wave came at the beginning of the 1970s when LSIs (Large
Scale Integrated circuits) with more than 1000 components had just been introduced
into the market.A mainframe computer was used for the simulation, and
each semiconductor company used its own proprietary simulators and device
models. However, the capability of the computer and accuracy of the model
were far from satisfactory, and there are many cases of the necessity of circuit
re-design after evaluation of the first chip.
The second wave hit us in the middle of 1980s, when the EWS (Engineering
Work Station) was introduced for use by designers. At that time, most of
the simulation tools were already provided by software vendors and standard
device models for public use were being established. The simulation of circuits
became considerably more accurate and the amount of re-design was
significantly reduced. The third wave started to flood us at the beginning of
this century, when the PC provided sufficiently high performance for circuit
simulation.We are facing the front of the third wave now. |
|