Method of breaking through etch stop layer

A method comprising:

• forming a first contact plug extending through a second interlayer dielectric (ILD), an etch stop, and a gate mask dielectric, the first contact plug contacting a source/drain contact, wherein the first contact plug is free from etch damage at an upper surface of the first contact plug;
• and
• forming a second contact plug extending through the second ILD, the etch stop, and the gate mask dielectric, the second contact plug contacting a gate electrode of a gate structure, the gate structure disposed over a semiconductor fin that extends from a substrate, the gate structure comprising:
• a gate dielectric on the semiconductor fin, the gate electrode on the gate dielectric, and a gate mask over the gate electrode, wherein a first ILD material laterally surrounds the gate structure, the gate mask dielectric extending continuously over an upper surface of the first ILD material, wherein the etch stop is disposed over the gate mask dielectric.

A method comprising:

• forming a mask over a first dielectric layer;
• forming a first opening in the mask, the first opening exposing a portion of the first dielectric layer;
• etching the first dielectric layer while using the mask as an etch mask to form a second opening in the first dielectric layer, the second opening exposing an etch stop layer;
• etching the etch stop layer while using the mask as an etch mask to form a third opening in the etch stop layer;
• and
• forming a first metal feature in the third opening, the first metal feature electrically coupled to a conductive element under the etch stop layer.