Soft Coating Particle Capture for EUV Lithography Overlay Errors
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Lithographic apparatuses face challenges in minimizing overlay errors due to wafer defectivity caused by small particles impacting and sticking to the wafer resist, which can lead to unacceptable circuit connections, especially as the minimum printable size decreases with each generation of EUV scanners.
Innovation Solution
A lithographic apparatus with a substrate stage and heat shields featuring a soft coating on compartment surfaces to capture particles, preventing them from reaching and sticking to the wafer resist, thereby reducing overlay errors and improving particle capture efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If imaging is performed using EUV radiation with short wavelength to reduce minimum printable size, then manufacturing precision is improved, but wafer defectivity increases due to particle impact on resist
Solution Approach 1:
A soft coating layer is introduced as an intermediary between particles and the wafer resist. This coating captures particles before they can reach the resist, thereby mitigating the harmful effect of particle impact while maintaining the benefits of short-wavelength EUV imaging for high manufacturing precision
Solution Approach 2:
The soft coating is applied beforehand on compartment surfaces to create a protective barrier. This pre-positioned cushioning layer is designed to capture particles that might otherwise contaminate the wafer resist, preventing defectivity before it occurs during the lithography process
2Device complexity
If particles are allowed to float freely in the compartment, then device complexity is reduced, but manufacturing precision deteriorates due to particle adhesion to resist
Solution Approach 1:
The soft coating surfaces self-capture particles through their inherent softness and surface properties, eliminating the need for complex active particle control mechanisms. Particles that float freely in the compartment are automatically captured when they contact the coated surfaces, maintaining manufacturing precision without adding device complexity
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The soft coating effectively captures particles smaller than 500 nm, preventing them from adhering to the wafer resist and enhancing the accuracy of pattern overlay, thus improving the yield and reducing thermal management issues in EUV lithography.
Implementation Method 1
a soft coating on said compartment surface for capturing particles
Data Source
AI summary
A lithographic apparatus including a substrate stage for supporting a structure in a compartment, the compartment having a compartment surface facing a top surface of the substrate in at least one operational configuration; and a soft coating on the compartment surface for capturing particles. A heat shield or component thereof for a lithographic apparatus, the heat shield or component thereof including a soft coating on at least one surface for capturing particles and a lithographic apparatus including such a heat shield.