1. Field of the Invention
The present invention relates to low dielectric constant films, and to precursors and methods useful in making such films.
2. Description of the Related Art
As semiconductor devices are scaled to higher processor speeds and smaller, denser structures, there is an increasing need to reduce resistance-capacitance (RC) delays present in interconnect wiring. Since the dielectric constant k is proportional to capacitance (C), scaling relationships require reductions in k values of the dielectric material. In addition to the requirement of low k values, reliability issues require that the dielectric material have a high degree of mechanical strength. Currently available dielectric films have low mechanical strength as k values decrease.
Among the various materials that are currently available for forming low k films, 1,3,5,7-tetramethylcyclotetrasiloxane (TMCTS) is a widely studied precursor for deposition of low k thin films used as interlayer dielectrics in integrated circuitry. Dielectric films formed from TMCTS typically have k values in a range of from about 2.6 to about 3.0, but lack sufficient hardness for large-scale integration. For next generation very large-scale integration (VLSI) devices, dielectrics will be required that have a dielectric constant k below 2.5 with hardness greater than about 1 gigaPascal (gPa).
Accordingly, the art continues to seek improvements in dielectric materials, in the quest for dielectrics having both high mechanical strength and low k value.