Selective barrier layer deposition using blocking layers

A method for forming an interconnection structure, comprising:

• forming a first conductive feature in a first dielectric material, wherein the first conductive feature has three surfaces in contact with a first liner layer, and a first barrier layer is disposed between the first liner layer and in contact with the first dielectric material and in contact with the first dielectric material;
• forming a first etch stop layer on the first dielectric material;
• forming a second dielectric material on the first etch stop layer;
• forming a first opening through the second dielectric material and the first etch stop layer to expose a top surface of the first conductive feature and a top surface of the first liner layer;
• forming a first blocking layer on the top surfaces of the first conductive feature and the first liner layer;
• selectively forming a second barrier layer on surfaces of the second dielectric material and the first etch stop layer in the first opening while the first blocking layer prevents formation of the second barrier layer on the top surfaces of the first conductive feature and the first liner layer;
• removing the first blocking layer to expose the top surface of the first conductive feature and the top surface of the first liner layer;
• forming a second blocking layer on the top surface of the first conductive feature and the top surface of the first liner layer;
• removing the second blocking layer to expose the top surface of the first conductive feature and the top surface of the first liner layer;
• and
• forming a first conductive material in the first opening so that a portion of the first conductive material is in direct contact with the first conductive feature and the first liner layer.

A method for forming an interconnection structure, comprising:

• forming a first conductive feature in a first dielectric material, the first conductive feature having a top surface;
• forming a first etch stop layer on the first dielectric material and the top surface of the first conductive feature;
• forming a second dielectric material on the first etch stop layer;
• forming a first opening through the second dielectric material and the first etch stop layer to expose the top surface of the first conductive feature;
• forming a first blocking layer on the top surface of the first conductive feature;
• conformally forming a first barrier layer on sidewalls of the first opening while the first blocking layer prevents formation of the first barrier layer on the top surface of the first conductive feature;
• removing the first blocking layer to form a spacing between a bottom of the first barrier layer and the top surface of the first conductive feature;
• forming a second blocking layer on the top surface of the first conductive feature;
• conformally forming a first liner on surfaces of the first barrier layer while the second blocking layer prevents formation of the first liner on the top surface of the first conductive feature;
• removing the second blocking layer to form a spacing between a bottom of the first liner and the top surface of the first conductive feature, wherein the bottom of the first liner is spaced apart from the top surface of the first conductive feature by a distance corresponding to a thickness of the second blocking layer;
• and
• forming a first conductive material in the first opening so that a portion of the first conductive material is in direct contact with the top surface of the first conductive feature and extends into the spacing under the first liner.