| abstract |
[Problem] To provide a method for forming an isolation structure having a low shrinkage percentage and a low tensile stress. n [Means for Solving] A first polysilazane composition containing a porogen is cast on the surface of a substrate to form a coat, and then the coat is fired to form a porous siliceous film having a refractive index of 1.3 or less. Thereafter, the surface of the porous siliceous film is soaked with a second polysilazane composition, and then fired to form an isolation structure of a siliceous film having a refractive index of 1.4 or more. |