Rock's law or Moore's second law, named for Arthur Rock, says that the cost of a semiconductor chip fabrication plant doubles every four years.  As of 2003, the price had already reached about 3 billion US dollars.
Rock's law can be seen as the economic flipside to Moore's law; the latter is a direct consequence of the ongoing growth of the capital-intensive semiconductor industry—innovative and popular products mean more profits, meaning more capital available to invest in ever higher levels of large-scale integration, which in turn leads to creation of even more innovative products.
The semiconductor industry has always been extremely capital-intensive, with ever-dropping manufacturing unit costs. Thus, the ultimate limits to growth of the industry will constrain the maximum amount of capital that can be invested in new products; at some point, Rock's Law will collide with Moore's Law.
It has been suggested that fabrication plant costs have not increased as quickly as predicted by Rock's law – indeed plateauing in the late 1990s – and also that the fabrication plant cost per transistor (which has shown a pronounced downward trend) may be more relevant as a constraint on Moore's Law.
- India Electronics & Semiconductor Association FAQs
- Does Moore's Law Still Hold?
- Moore's Law article by Bob Schaller
- 2006 Chemical & Engineering News article on materials suppliers challenged by rising costs[dead link]
- Rock's Law Fails to Hold