Etching Chemistry Process Optimization of Ethylene Diluted with Helium (C₂H₄/He) in Interconnect Integration

Area of Science:

• Materials Science
• Chemical Engineering
• Semiconductor Manufacturing

Background:

• Aluminum (Al) interconnects are crucial in semiconductor devices.
• Etching processes can form polymers on Al sidewalls, affecting device performance.
• Passivation gases play a role in controlling polymer formation during etching.

Purpose of the Study:

• To investigate the impact of different passivation gases on polymer properties during Al etching.
• To compare the effects of nitrogen (N2) and ethylene diluted with helium (C2H4/He).
• To analyze polymer composition, thickness, strength, and residual chlorine levels.

Main Methods:

• Comparative analysis of polymers formed using N2 and C2H4/He passivation gases.
• Characterization of polymer thickness, strength, and elemental composition (C, O).
• Measurement of residual chlorine content post-etch.

Main Results:

• Ethylene (C2H4) resulted in thinner, weaker polymers compared to nitrogen (N2).
• Polymers formed with C2H4 had lower residual chlorine levels.
• Elemental analysis showed lower carbon and higher oxygen content in C2H4-based polymers.

Conclusions:

• The choice of passivation gas significantly influences polymer characteristics during Al etching.
• C2H4 is a promising alternative to N2 for optimizing Al etching processes.
• Understanding these effects is vital for enhancing the reliability of Al-based interconnects.