EUV Mask Blank Defect Reduction via PVD Chamber Liner
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Solution Overview
Problem
Extreme ultraviolet lithography systems face challenges in reducing defects in EUV mask blanks due to unbalanced stress from silicon and molybdenum deposition, which leads to stress-related defects, making it difficult to achieve zero killer defects in the working area of the blank.
Innovation Solution
A method involving the deposition of specific bilayers such as SiNx/SiOxNy, SiNx/Mo, and SiOxNy/Mo bilayers on the interior components of a multi-cathode physical vapor deposition (PVD) chamber, followed by the formation of a multilayer stack of alternating molybdenum and silicon layers on a substrate, to enhance adhesion and reduce defect generation during the manufacturing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If silicon and molybdenum deposition is performed in the PVD chamber, then the multilayer stack is formed for EUV reflection, but unbalanced stress leads to stress-related defects on the blank
Solution Approach 1:
A liner is introduced as an intermediary component between the chamber walls and the deposition process. The liner accumulates stress from silicon and molybdenum deposition, acting as a stress buffer that protects the EUV mask blank from stress-related defects. The liner is periodically replaced after accumulating sufficient stress, maintaining a stable deposition environment.
Solution Approach 2:
The liner serves as a replaceable copy or surrogate that absorbs the harmful effects of unbalanced stress. Instead of the stress affecting the valuable EUV mask blank directly, the liner provides a sacrificial surface that can be depleted and replaced, copying the stress accumulation function while protecting the primary product.
2Manufacturing precision
If the liner is rotated during deposition, then uniform coverage is achieved on the liner, but the deposition process time increases
Solution Approach 1:
The liner is made rotatable rather than stationary, allowing it to dynamically change orientation during deposition. This rotational movement ensures that all surfaces of the liner receive uniform material deposition, creating consistent stress accumulation and preventing localized defect formation. The rotation speed is optimized to balance uniformity with process efficiency.
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
This approach significantly reduces defects in EUV mask blanks, improving the yield of zero-defect production runs from 10% to over 50% by providing improved adhesion and uniform coverage, thereby enhancing the manufacturing efficiency of EUV mask blanks.
Implementation Method 1
depositing a first layer on a portion of a chamber interior of a multi-cathode physical vapor deposition (PVD) chamber; depositing a second layer on the first layer to form a bilayer
Data Source
AI summary
Methods for the manufacture of extreme ultraviolet (EUV) mask blanks and production systems therefor are disclosed. A method for forming an EUV mask blank comprises forming a bilayer on a portion of a multi-cathode PVD chamber interior and then forming a multilayer stack of Si/Mo on a substrate in the multi-cathode PVD chamber.