The second half of the twentieth century and the beginning of the twenty first have
been characterized by the most impressive industrial revolution ever seen. In approximately
40 years, the complexity of integrated circuits (ICs) has increased by a
factor of 109, with a corresponding reduction of the cost per bit by eight orders of
magnitude.
Not only has this evolution allowed dramatic progress in all scientific fields (large
computers, space probes, etc.), but also has fueled the economic development with
the raise of new markets (personal computers, cellular phones, etc.) and even social
revolutions (world wide web, global village, etc.).
In last years, however, the situation has significantly changed: the continuous
scaling down of device size has eventually brought the IC major technique, photolithography,
to its limits. Overcoming its original limits has been proved to be
possible, but the price to pay for that has changed the playing rules – while at the
beginning of the IC history the evolution was driven by technology, now it is driven
by economy, the cost of a medium size production plant being in the range of a few
billion dollars.