Patterning with Amorphous Carbon Thin Films

Amorphous carbon hard mask films grown with plasma enhanced chemical vapor deposition are an enabling technology for advanced front-end-of-line patterning technologies. These films must have a low etch rate and be weakly roughened in dielectric etch chemistries, high transparency at lithography alignment wavelengths, and the mechanical properties to mitigate elastic instabilities such as line bending. The deposition process affects all of these parameters through the resulting structure and composition. Highly graphitic films deposited at 550°C are common; however, other process spaces relying on ion bombardment rather than temperature can create less graphitic films with improved film properties like transparency, hardness, and etch selectivity.