BACKGROUND

The semiconductor integrated circuit (IC) industry has experienced exponential growth. Technological advances in IC materials and design have produced generations of ICs, where each generation has smaller and more complex circuits than the previous generation. In the course of IC evolution, functional density (e.g., the number of interconnected devices per chip area) has generally increased while geometry size (e.g., the smallest component or line that can be created using a fabrication process) has decreased. With such small size, the space between two signal lines is decreased, and the noise resulting from one signal line to the other inevitably increases. However, for a signal line carrying a clock signal, the noise is undesired.

