Extreme ultraviolet (EUV) pellicles are in high demand for improving the yield of EUV lithography. However, when the EUV pellicle membrane is destroyed inside the scanner, machine availability is significantly affected. The deflection of EUV pellicle membranes needs to be thoroughly studied, because when the membrane deflects beyond its limit, the membrane contacts the scanner components and leads to failure. To propose guidelines for sustaining the EUV pellicle membrane during lithography, the deflection of the EUV pellicle membrane with a range of mechanical properties should be investigated. We verified the feasibility of the finite element method (FEM) analysis by comparing the analysis results with the experimental results. Subsequently, the impact of the mechanical properties on the deflection of a full-sized (110 mm × 143 mm) membrane was investigated using the FEM analysis. The residual stress showed 6.28 and 2.9 times higher impact on the deflection compared to the Poisson’s ratio and elastic modulus, respectively. Finally, the deflection results for 84 different mechanical properties are presented. The residual stress was determined to be a crucial and controllable parameter. The presented guidelines can be used as a design rule for developing EUV pellicle membranes. |
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Pellicles
Extreme ultraviolet
Finite element methods
Silicon
Extreme ultraviolet lithography
Structural analysis
Image processing