Lithographic Apparatus Multi-Beam Interference Patterning
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current lithographic techniques face limitations in achieving high resolution and pattern width control for small features and contact holes below 85 nm, as existing resolution enhancement techniques are not feasible for printing half-pitches below a certain critical dimension due to constraints in numerical aperture and process latitude.
Innovation Solution
A lithographic apparatus utilizing a beam splitter to create coherent radiation beams that form an interference pattern on a substrate, synchronized with the motion of a substrate stage to ensure precise superimposition of patterns, enhancing resolution and pattern uniformity by averaging optical aberrations across the imaging field.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional resolution enhancement techniques (phase shift masks, SRAF, off-axis illumination) are used, then pattern resolution is improved, but process latitude and feasibility for features below 85 nm are lost
Solution Approach 1:
The invention changes the fundamental parameter of illumination geometry from conventional on-axis or off-axis single-beam illumination to multi-beam interference illumination. By controlling the interference of multiple coherent beams, the system achieves high resolution for sub-85nm features while maintaining process latitude through adjustable beam parameters (number of beams, angles, coherence) that can be optimized for different pattern types.
Solution Approach 2:
The invention segments the illumination into multiple discrete coherent beams rather than using a continuous illumination field. This segmentation allows independent control of each beam's parameters (angle, phase, intensity), enabling precise interference pattern formation that achieves high resolution while maintaining adaptability for different feature sizes and types.
2Measurement precision
If numerical aperture is increased to achieve smaller half-pitch, then resolution is improved, but lens technology constraints prevent achieving required NAPS values
Solution Approach 1:
The invention replaces the mechanical/optical approach of increasing numerical aperture through lens design with an interference-based approach. Instead of relying on high-NAPS lenses that are beyond current manufacturing capabilities, the system uses multiple coherent beams interfering at controlled angles to achieve the same resolution effect, effectively substituting lens complexity with beam control.
Solution Approach 2:
The invention moves from a single-dimensional resolution improvement approach (increasing NAPS) to a multi-dimensional approach using interference patterns. By controlling the spatial arrangement and phase relationships of multiple beams in three-dimensional space, the system achieves high resolution without requiring extreme numerical aperture values.
3Manufacturing precision
If interference pattern formation with multiple beams is used, then pattern resolution and uniformity are improved, but system complexity increases
Solution Approach 1:
The invention introduces beam combining optics as an intermediary component that simplifies the overall system architecture. Instead of requiring independent control of multiple complex optical paths, the beam combiner merges multiple coherent beams in a controlled manner, reducing system complexity while maintaining the interference pattern formation capability needed for high precision patterning.
4Manufacturing precision
If substrate stage motion is synchronized with radiation source repetition rate, then pattern uniformity is improved, but control system complexity increases
Solution Approach 1:
The invention implements a feedback-based synchronization system where the substrate stage motion is continuously monitored and adjusted based on the radiation source repetition rate. This feedback mechanism ensures that the interference pattern remains uniformly registered on the substrate throughout the exposure process, achieving high pattern uniformity while using a relatively simple control architecture.
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 allows for high-resolution pattern imaging with improved control and uniformity, achieving pattern resolutions of about 35 to 40 nm half-pitches, surpassing the limitations of existing technologies by optimizing the interference pattern formation and substrate motion synchronization.
Implementation Method 1
a beam splitter configured to split a beam of radiation into a plurality of radiation beams
Implementation Method 2
a beam combiner adapted to redirect and combine at least a portion of the plurality of radiation beams to form an interference pattern on the substrate
Data Source
AI summary
A lithographic apparatus is presented. The lithographic apparatus includes a beam splitter configured to split a radiation beam into a plurality of radiation beams; a substrate stage configured to support a substrate; a beam combiner adapted to redirect and combine at least a portion of the plurality of radiation beams to form an interference pattern on the substrate; and a control unit in communication with the substrate stage and a radiation source configured to output the beam of radiation, the control unit configured to synchronize a motion of the substrate stage with a repetition rate at which the beam of radiation is output by the radiation source.