Eschweiler & Associates, LLC
Air-gap scheme for BEOL process
The present disclosure relates a method of forming a back-end-of-the-line (BEOL) metallization layer having an air gap disposed between adjacent metal interconnect features, which provides for an inter-level dielectric material with a low dielectric constant, and an associated apparatus. In some embodiments, the method is performed by forming a metal interconnect layer within a sacrificial dielectric layer overlying a substrate. The sacrificial dielectric layer is removed to form a recess extending between first and second features of the metal interconnect layer. A protective liner is formed onto the sidewalls and bottom surface of the recess, and then a re-distributed ILD layer is deposited within the recess in a manner that forms an air gap at a position between the first and second features of the metal interconnect layer. The air gap reduces the dielectric constant between the first and second features of the metal interconnect layer.
Taiwan Semiconductor Manufacturing Co., Ltd.
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Ru-Shang Chih-Fu Jen-Pan
Hsiao Chang Wang