Improving Performance Of Blades In EUV Lithography Machines

Abstract

Ceramics are being explored as an alternative material by ASML to replace their stainless steel 316L (SS316L) reticle masking blades. Ceramics offer distinct advantages over stainless steel in the semiconductor industry. While stainless steel exhibits good mechanical strength, ceramics excel in electrical insulation and thermal conductivity, making them essential for semiconductor manufacturing. Ceramics, with their lower thermal expansion coefficient, enhanced chemical stability, lightweight nature, and dielectric properties, are essential for improving the performance, miniaturization, and reliability of semiconductor devices. This research addresses the challenge of replacing the SS316L blades in ASML’s EUV lithography reticle masking with high-purity alumina (99.7%) through binder jetting. Concurrently, emphasis was placed on optimizing the existing REMA blade design for the binder jetting technique. This research further assesses the thermo-mechanical performance of the new blade suggesting the necessity of cooling channels in the new blades. High-purity alumina was chosen for its superior material properties compared to SS316L. The research also focuses on analyzing the impact of particle size, printing parameters, and sintering conditions on the densification and mechanical properties of binder-jetted alumina samples. Unimodal 20 μm, unimodal 10 μm, and trimodal (equal concentrations of 10, 5, and 2 μm) powder batches were printed using binder jetting. The trimodal samples with 90% binder saturation exhibited the best results in green body density (61.3%) and sintered body density (66.9%). The Young’s modulus and flexural strength achieved by the trimodal sample was also the highest with a value of 77.3 ± 4.9 GPa and flexural strength of 59.5 ± 3.2 MPa. To enhance densifications further, it is recommended to incorporate sintering additives in the powder mixture and/or utilize nanoparticle densifiers in the binder. Additionally, employing the discrete element method using smaller particles with a multimodal powder mixture is also recommended for achieving higher densification.