Semiconductor device structure and methods of forming the same

An interconnection structure, comprising:

• a dielectric layer;
• a first conductive feature disposed in the dielectric layer;
• a conductive layer disposed over the dielectric layer, wherein the conductive layer includes a first portion and a second portion adjacent the first portion, and the second portion of the conductive layer is disposed over the first conductive feature;
• a first barrier layer in contact with the first portion of the conductive layer;
• a second barrier layer in contact with the second portion of the conductive layer;
• a support layer in contact with the first and second barrier layers, wherein an air gap is located between the first and second barrier layers;
• and
• a first dielectric material disposed on the support layer, wherein a top surface of the first dielectric material and a top surface of the first portion of the conductive layer are substantially coplanar.

A method, comprising:

• depositing a conductive layer over a dielectric layer;
• forming an opening in the conductive layer to expose a portion of the dielectric layer, wherein the opening separates the conductive layer into a first portion and a second portion;
• depositing a degradable layer in the opening;
• recessing the degradable layer in the opening;
• depositing a support layer in the opening on the degradable layer;
• removing the degradable layer to form an air gap in the opening;
• depositing a first dielectric material on the support layer;
• and
• selectively forming a metal oxide layer on the first dielectric material.