Low Dielectric Constant Materials

The history of low-k materials from a chemistry perspective has been presented. Two important points which have emerged about the design and the implementation of these materials into chip integration are the research in the field of low-k materials is very much driven by the technology and the introduction of porous low-k materials in manufacturing is extremely challenging. The reduction of dielectric constant by introducing porosity can be achieved either in PECVD or spin-on materials. Due to the covalent bonding between the porogen and the matrix for PECVD materials, the thermal treatment for pore generation had to be significantly more aggressive. The combination of a thermal curing with UV exposure not only guarantees an almost complete porogen removal in a short period of time but also increases the mechanical robustness of the deposited films. The control of the porosity and the design of tougher materials at high levels of porosity appear to be essential for the successful utilization of ultralow-k materials.