Methods for fabricating integrated circuits with improved contact structures

A method for fabricating integrated circuits, the method comprising:

• providing a semiconductor substrate disposed with a device therein and/or thereon;
• forming a contact structure in electrical contact with the device, wherein the contact structure includes a barrier layer and a plug metal;
• forming a dielectric layer and a hardmask over the contact structure;
• etching the hardmask and dielectric layer to form a via opening through the hardmask and dielectric layer and to expose the contact structure;
• forming a contact cap in the via opening over the plug metal and the barrier layer;
• removing a remaining portion of the hardmask with a wet etchant, wherein the contact cap inhibits the wet etchant from etching the barrier layer;
• and
• filling the via opening with a conductive material to form an interconnect to the contact structure.

A method for fabricating integrated circuits, the method comprising:

• providing a semiconductor substrate disposed with a device therein and/or thereon;
• forming a contact structure in electrical contact with the device, wherein forming the contact structure includes depositing fluorine free tungsten (FFW), tungsten nitride, or tungsten carbide to form a barrier layer and forming a plug metal overlying the barrier layer;
• forming a hardmask overlying the contact structure;
• performing an etch to form a via opening through the hardmask and to expose the barrier layer and the plug metal;
• removing a remaining portion of the hardmask with a wet etchant, wherein the contact structure is configured to inhibit the wet etchant from etching the barrier layer;
• and
• filling the via opening with a conductive material to form an interconnect to the contact structure.