METHOD FOR FABRICATING SEMICONDUCTOR DEVICE WITH POROUS DIELECTRIC STRUCTURE

1 . A method for fabricating a semiconductor device, comprising:

providing a substrate;

forming two conductive features apart from each other over the substrate;

forming a porous middle layer positioned between the two conductive features and adjacent to the two conductive features;

depositing an energy-removable material between the two conductive features and adjacent to the two conductive features; and

performing an energy treatment to transform the energy-removable material into a porous middle layer;

wherein a porosity of the porous middle layer is between about 25% and about 100%.

2 . The method for fabricating the semiconductor device of claim 1 , wherein the energy-removable material comprises a base material and a decomposable porogen material.

3 . The method for fabricating the semiconductor device of claim 2 , wherein an energy source of the energy treatment is heat, light, or a combination thereof.

4 . The method for fabricating the semiconductor device of claim 3 , wherein the base material comprises methylsilsesquioxane or silicon oxide.

5 . The method for fabricating the semiconductor device of claim 4 , further comprising forming a first stop layer on the substrate, wherein the first stop layer has a thickness between about 1 nm and about 50 nm.

6 . The method for fabricating the semiconductor device of claim 5 , further comprising forming a plurality of fins on the first stop layer.