14:00 〜 14:30
[G-1-01 (Invited)] Considerations for post-Cu Alternative Metal BEOL Interconnects ~ Challenges and Solutions ~
Post-Cu alternative conductors have been studied extensively as an approach to enable lower line resistance and excellent reliability for sub-20nm pitch technologies due to their smaller scattering effect, less stringent barrier/liner requirement, and higher melting point compared to Cu.
However, the repetitive line CD variability observed post metal deposition is one of the key challenges for alternative metal interconnects in case of utilizing a damascene process scheme. Therefore, we have clarified the mechanism of the line wiggling observed post metal deposition and explored methods to alleviate this line CD variability.
Furthermore, forming the lines for alternate conductors through a subtractive scheme should be an effective approach to suppress line wiggling issues. Thus, we have evaluated and demonstrated fully subtractive Ru interconnects where a TopVia structure and airgap were employed, which enabled a reduction in line resistance, via resistance and capacitance.
However, the repetitive line CD variability observed post metal deposition is one of the key challenges for alternative metal interconnects in case of utilizing a damascene process scheme. Therefore, we have clarified the mechanism of the line wiggling observed post metal deposition and explored methods to alleviate this line CD variability.
Furthermore, forming the lines for alternate conductors through a subtractive scheme should be an effective approach to suppress line wiggling issues. Thus, we have evaluated and demonstrated fully subtractive Ru interconnects where a TopVia structure and airgap were employed, which enabled a reduction in line resistance, via resistance and capacitance.