Semiconductor structure and method for fabricating the same

A method of forming a conducting structure in a semiconductor device, comprising:

• patterning a first recess feature through a dielectric layer wherein a conductive feature is accessible in a lower device layer via the first recess feature;
• forming a vertical conductive feature in the first recess feature;
• forming, under a first process temperature, an interposing layer of substantially an uniform thickness extending laterally over a planar projection of the vertical conductive feature, the interposing layer being in contact with the vertical conductive feature;
• forming, under a second process temperature, a metal layer over the interposing layer, wherein the second process temperature is higher than the first process temperature;
• forming an over layer over the metal layer, wherein the overlayer contains titanium and comprises a fine grain lower sub-layer and a coarse grain upper sub-layer;
• and
• patterning the interposing layer and the metal layer through the overlayer to form a lateral conductive feature, the lateral conductive feature being over and in contact with the vertical conductive feature.