Methylated porous low-k materials: critical properties and plasma resistance

Porous OSG low-k dielectrics deposited by using TEOS and MTEOS mixture with different ratios and Brij® 30 surfactant. The deposited samples contain a different concentration of terminal methyl groups that is proportional to MTEOS concentration. An increase in the methyl groups concentration by changing TEOS/MTEOS ratio decreases the open porosity, k-value, and Young’s modulus and increases the mean pore radius although the template concentration was kept constant. Plasma damage by fluorine radicals depends on the carbon concentration in the films. It can be reduced by 60% when the carbon concentration in the film exceeds 10 atomic percent as measured by XPS (the films deposited with TEOS/MTEOS ratio 40/60).