Study on ZrSi₂ as a Candidate Material for Extreme Ultraviolet Pellicles

Area of Science:

• Materials Science
• Optical Engineering
• Semiconductor Manufacturing

Background:

• Extreme ultraviolet (EUV) pellicles are crucial for protecting masks from contamination during semiconductor lithography.
• Pellicles require high EUV transmittance, low reflectivity, and excellent thermomechanical stability.
• Increasing EUV source power necessitates advanced pellicle materials.

Purpose of the Study:

• To determine optimal optical constants for EUV pellicles through simulation.
• To evaluate zirconium disilicide (ZrSi2) as a candidate material for EUV pellicles.
• To fabricate and characterize a ZrSi2-based EUV pellicle composite.

Main Methods:

• Optical simulations to identify ideal optical constants.
• Co-sputtering technique for depositing ZrSi2 thin films.
• Experimental evaluation of thermal, optical, and mechanical properties.

Main Results:

• ZrSi2 was identified as a suitable material based on simulations.
• A ZrSi2 pellicle composite was successfully fabricated.
• Measured EUV transmittance of 92.7% and reflectivity of 0.033% were achieved.
• Ultimate tensile strength reached 3.5 GPa.

Conclusions:

• ZrSi2 thin films meet the stringent optical and mechanical requirements for EUV pellicles.
• The fabricated ZrSi2 pellicle demonstrates high performance and applicability.
• This material offers a viable solution for advanced EUV lithography mask protection.