Investigation of Amorphous Silicon as Dry Etch Hard Mask in BEOL Low-k Dielectric Patterning

In order to better adapt to ever-evolving manufacturing processes and improve critical dimension (CD) control in CMOS Back End of Line (BEOL), an investigation using amorphous silicon (a-Si) as the dry etch hard mask in low-k dielectric patterning is performed, which targets for a higher selectivity toward low-k dielectric than the conventional metal hard mask.