Method for forming dielectric film to improve adhesion of low-k film

A method for forming a semiconductor structure, the method comprising:

• providing a semiconductor substrate;
• forming an etch stop layer over the semiconductor substrate;
• forming an initial layer over and adjacent the etch stop layer in a chamber using a CVD method;
• gradually changing process conditions of the initial layer to form a transition layer on the initial layer in the chamber, wherein the transition layer is adjacent the etch stop layer;
• in-situ forming a low-k dielectric layer on the transition layer in the chamber, wherein during the process of forming the transition layer, process conditions are changed so that process conditions for forming a top portion of the transition layer substantially match process conditions for forming the low-k dielectric layer;
• and
• forming damascene openings in the low-k dielectric layer.

A semiconductor structure comprising:

• a semiconductor substrate;
• a dielectric layer over the semiconductor substrate;
• an etch stop layer over and adjacent the dielectric layer;
• an adhesion layer over and adjacent the etch stop layer, wherein the adhesion layer comprises a transition sub-layer, and wherein the transition sub-layer has a composition that gradually changes from a lower portion to an upper portion;
• a low-k dielectric layer on the adhesion layer;
• and
• damascene openings in the low-k dielectric layer.