EUV Reticle Inspection Spectral Purity Filter

The patent changes the material parameters by selecting specific materials (Zirconium and Silicon) with appropriate layer thicknesses (e.g., 5-10 nm Zr and 15-20 nm Si layers) to achieve high EUV transmission. This parameter optimization resolves the contradiction by finding material compositions that simultaneously provide ease of manufacture and high transmission rates that prevent thermal damage and image flare.

The patent employs composite multilayer structures combining Zirconium and Silicon layers, where each material contributes different properties. The Zr layers provide high EUV reflectivity while Si layers provide transmission, creating a composite beam splitter that achieves both high transmission and structural integrity, preventing thermal damage and image flare while remaining manufacturable.

The patent merges the spectral filtering function with the beam splitter function into a single integrated component. The multilayer Zr-Si structure simultaneously performs beam splitting and spectral purification by reflecting unwanted wavelengths while transmitting EUV light, eliminating the need for separate filter components and reducing overall device complexity.

The beam splitter component is designed to perform multiple functions: it splits the EUV beam, filters unwanted wavelengths, and prevents thermal damage and image flare. This multi-functional design resolves the contradiction by incorporating spectral purification capabilities directly into the beam splitter, avoiding additional device complexity while maintaining all necessary functions.

The patent optimizes layer thickness parameters to ranges (e.g., Zr: 5-10 nm, Si: 15-20 nm) that provide high transmission efficiency and signal-to-noise ratio while being manufacturable with standard precision capabilities. These parameter selections resolve the contradiction by finding optimal values that achieve high reliability without requiring extreme manufacturing precision.

The patent applies different layer thicknesses and material properties at different positions in the multilayer structure to optimize local performance. By varying the thickness and composition of individual layers (e.g., alternating Zr and Si layers with specific thicknesses), the system achieves high overall transmission efficiency and signal-to-noise ratio while maintaining manufacturability through localized quality variations rather than uniform high precision requirements throughout.