A porous silica coating having a dielectric constant of less than 2.5, a semiconductor device comprising the porous silica coating formed therein, and a coating composition for forming the porous silica coating. The coating composition is composed of an aluminum-containing polysilazane and a polyacrylate or polymethacrylate ester in an organic solvent. The coating composition is coated and then fired, thereby to obtain a porous silica coating. The porous silica coating can be used as an interlayer dielectric by forming on a semiconductor device.
展开▼