Detection of open or closed porosity in low-κ dielectrics by solvent diffusion

The presence of open porosity in a porous interlayer dielectric (ILD) can seriously degrade the ultimate performance and reliability of a device. A simple method for detecting the open porosity in ILDs would facilitate the design of materials with pore morphologies compatible with the required specifications of a particular device. The measurement of effective diffusion coefficients in a low-κ ILD over a range of porosities is shown to permit the detection of open porosity. An example illustrating the simplicity of this method is presented using toluene solvent in a well-characterized porous organosilicate material. The result using this method is consistent with available data in the literature.