In the selection of ultra low k materials, process compatibility is a very important factor. Plasma processing plays a critical role in enhanced interconnect integration. It is therefore important to study plasma interaction with the ultra low k materials and its effects on the structure and property of these materials. X-ray reflectivity (XRR) measurement can be used to measure film thickness, density and interface roughness, which are important parameters to check for after plasma treatments. In the current study, porous SiLK (p-SiLK) was treated with various plasmas, such as O2, O2/N2, H2/N2, CH2F2/Ar and CF4/O2. XRR results indicate that the density of the p-SiLK films remains unchanged after various plasma treatments. Surface roughening occurs during the plasma treatments, accompanied by the decrease in film thickness. Plasma-induced surface roughening was also observed using atomic force microscope (AFM). Such roughening is more severe for plasma treatments using oxygen-containing plasmas. FTIR analysis indicates that the chemical structure of the p-SiLK films is not significantly affected by plasma treatment. It is reasonable to conclude that oxidation of the surface plays a major role in the plasma-induced change in surface roughness and film thickness.

Airborne molecular contamination poses a serious problem for advanced wafer fabrication as the devices are continually scaled down. The amount of this contamination may be only a few monolayers, which are extremely difficult to detect by the commonly used analytical techniques, such as FTIR. ToF-SIMS has extremely high surface sensitivity for the analysis of trace contaminants on wafer surfaces. The high mass resolution of ToF-SIMS is also a powerful tool for the identification of the contaminants. In the current study, ToF-SIMS is used to monitor the build-up of airborne amine contamination on Black Diamond1 surfaces. It has been found that cleaning of the Black Diamond surfaces using wet chemicals can lead to photoresist poisoning. Thermal desorption-GC-MS analysis revealed that wet cleaning would result in the accumulation of hydrocarbons on the Black Diamond surfaces. ToF-SIMS shows that amines can build up gradually on the Black Diamond surfaces after wet cleaning, probably via airborne molecular contamination. For the Black Diamond wafers which did not go through the wet cleaning process, there was no significant increase of amines on the wafer surfaces. The amount of amines on the Black Diamond surfaces depends on the chemicals used in the cleaning processes and the wafer storage conditions. The level of amine contamination can be significantly reduced after the samples are heated up to 300°C for a few minutes in inert atmosphere.