Chips are the tiny silicon-based devices that run much of the world's electronic equipment.
Because of the growing complexity of these devices and the industry's hypercompetitiveness, chip companies sue one another even more than many of their tech brethren. The number of patent cases heard by U.S. district courts has grown 30 percent since 1995, many of them semiconductor-related, according to federal statistics. Stakes are high for several reasons. Semiconductor companies spend billions to develop and manufacture new chips. The separate legal battles initiated by Rambus and Xilinx illustrate just how diverse, complicated and drawn-out these patent cases can be.