I am indebted to my supervisor, Andy Hopper, for his encouragement and support. He first introduced me to the topic of computer aided design of integrated circuits when I was an undergraduate, and has been a source of guidance ever since. I am also indebted to Roger Needham for extending the facilities of the Computer Laboratory. I am grateful that both Andy and Roger have demonstrated quite remarkable patience. The Science and Engineering Research Council provided funding for three years for which I am thankful.

Of the many people who have been a source of help, I would particularly like to thank David Wheeler for a number of stimulating discussions, and Haroon Ahmed of the Microcircuit Engineering Laboratory for introducing me to the technology of three-dimensional circuits. Alan Mathewson and Ciaran Cahill, of the National Microelectronics Research Centre, University College, Cork, have contributed to my further understanding of the technological possibilities. Elements of the systems used in the case study described in chapter two were developed by myself, Jeremy Dion, Alan Jones, Tony Mann, Trevor Morris, John Porter, Peter Robinson and Chris Stenton. I would like to thank Tony Mann and John Porter for reminding me about the details of the placement and routing schemes.

Chris Stenton and Steve Temple have contributed many helpful suggestions particularly in the experimental stages and were diligent proof readers, as were Tim Cole and David Greaves. I am grateful for their suggestions for improvements.