Phase-Based EUV Patterning Device for High Contrast Imaging
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Solution Overview
Problem
Lithographic apparatuses using EUV radiation face challenges in producing high contrast images due to lossy optical components and limited power sources, making it difficult to achieve high resolution and commercial productivity simultaneously.
Innovation Solution
A patterning device is designed without light absorber material, using phase differences to define features, with edges between regions of different phases to create a dense array of patterns, and applying negative bias to optimize feature size and contrast, allowing for improved EUV lithography performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If EUV radiation with short wavelength is used to reduce minimum printable size, then resolution is improved, but image contrast deteriorates due to lossy optical components and limited source power
Solution Approach 1:
The patent changes the patterning mechanism from intensity-based (absorber material blocking light) to phase-based (edges between regions of different phase). This parameter change in the fundamental mechanism allows high contrast image formation without requiring high illumination intensity, thus resolving the contradiction between resolution and image contrast in EUV lithography
Solution Approach 2:
The invention utilizes phase differences (phase transitions in the optical path) to define pattern features. By creating edges between regions of different phase rather than relying on light absorption, the system achieves high contrast imaging with limited EUV source power, thereby maintaining both high resolution and image contrast
2Productivity
If conventional DUV lithography with multiple exposures is used, then productivity is maintained, but manufacturing precision deteriorates for smaller device features
Solution Approach 1:
The patent changes the fundamental patterning approach by eliminating absorber material and using phase differences alone to define features. This enables single-exposure EUV lithography to achieve the manufacturing precision previously only attainable through multiple DUV exposures, thus improving both precision and productivity simultaneously
3Device complexity
If absorber material is used in patterning device, then pattern definition is simplified, but radiation dose requirement increases reducing throughput
Solution Approach 1:
The invention extracts and removes the absorber material component from the patterning device, relying solely on phase differences to define pattern features. This elimination of absorber material reduces the radiation dose required for pattern formation, thereby increasing throughput while maintaining adequate pattern definition capability
Solution Approach 2:
The patent changes the patterning mechanism from absorber-based to phase-based definition. This parameter change in the fundamental mechanism reduces the radiation dose requirement, improving throughput without compromising pattern definition quality
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 enhances image contrast and reduces the radiation dose required, improving throughput and local critical dimension uniformity, enabling the production of smaller features with higher resolution in EUV lithography.
Implementation Method 1
configured to define features of the pattern in that area by phase differences alone
Implementation Method 2
features of the pattern are defined by etching the multilayer reflective structure in selected regions so as to impart substantially opposite phases to reflected radiation
Data Source
AI summary
A patterning device carries a pattern of features to be transferred onto a substrate using a lithographic apparatus. The patterning device is free of light absorber material, at least in an area. The pattern of features in the area may include a dense array of lines, trenches, dots or holes. Individual lines, holes, etc. are defined in at least one direction by pairs of edges between regions of different phase in the patterning device. A distance between the pair of edges in the at least one direction is at least 15% smaller than a size of the individual feature to be formed on the substrate once adjusted by a magnification factor, if any, of the lithographic apparatus. The patterning device may be adapted for use in EUV lithography. The patterning device may be adapted for use in a negative tone resist and development process.