Preparing Mesoporous Low-k Films with High Mechanical Strength from Noncrystalline Silica Particles

The coating solutions composed of surfactant Tween 80 and noncrystalline silica particles with an average size of 4.6 nm were synthesized through a short hydrothermal process. They were spun onto silicon wafers to obtain mesoporous low-k films. The film properties were compared with those of the films made of MFI zeolite nanocrystals with an average size of around 40 nm. The films from noncrystalline particles showed higher surface uniformity and higher mechanical strength, and possessed k values of smaller than 2 and low leakage current densities, which all reached the needs of the future IC industry. The preparation processes and time for the noncrystalline silica particles are much simpler and shorter than those for the MFI zeolite nanocrystals. As a result, the processes developed in this research can save the production cost and time for producing low-k films in the future.