Interconnect structure and method for manufacturing the interconnect structure

A method for forming an interconnect structure, comprising:

• forming a first interlayer dielectric (ILD) layer over a substrate;
• forming a contact in the first ILD layer;
• forming a second ILD layer over the first ILD layer;
• forming a first opening in the second ILD layer and obtaining an exposed side surface of the second ILD layer over the contact;
• and
• irradiating a microwave on the second ILD layer, thereby forming a densified dielectric layer at the exposed side surface of the second ILD layer and an oxide layer over the contact.

A method for forming an interconnect structure, comprising:

• forming a first interlayer dielectric (ILD) layer over a substrate;
• forming a contact recess in the first ILD layer;
• forming a densified dielectric layer at a sidewall of the contact recess, comprising:
• irradiating a microwave on the first ILD layer;
• forming a contact in the first ILD layer;
• and
• forming a second ILD layer over the first ILD layer.