Projection Lens Array Manipulators for Multi-Beamlet Lithography
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current charged particle multi-beamlet systems face challenges in achieving high resolution and throughput due to limitations in spot size, point spread function, and the complexity of individually controlling numerous beamlets, which leads to increased size, cost, and aberrations.
Innovation Solution
The implementation of array manipulators, such as group deflector arrays and condenser lens arrays, directs multiple beamlets towards a single projection lens, increasing the number of beamlets without the need for extreme miniaturization, thus avoiding common cross-overs and reducing aberrations, and allowing for patterned beamlet projection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If individually controlled lenses are used for each beamlet, then beamlet control precision is improved, but device complexity and system size increase
Solution Approach 1:
Multiple individually controlled beamlets are merged and directed through a single shared projection lens. The beamlet manipulator array individually controls each beamlet's position and focus, while the shared projection lens handles the final projection, combining individual control with shared optical infrastructure to reduce system complexity.
Solution Approach 2:
The shared projection lens serves multiple beamlets simultaneously, performing the projection function for many beamlets with a single optical element. This universal approach eliminates the need for dedicated projection lenses for each beamlet, reducing device complexity while maintaining individual beamlet control through the manipulator array.
2Productivity
If a large number of beamlets are used, then productivity is improved, but aberrations and resolution decrease
Solution Approach 1:
The common cross-over point, which causes aberrations when many beamlets converge, is extracted or eliminated from the system. The beamlet manipulator array directs beamlets to converge at or near the projection lens without requiring a common cross-over in mid-air, removing the source of aberrations while maintaining high beamlet counts for productivity.
Solution Approach 2:
The beamlet manipulator array acts as an intermediary between the beamlet generation stage and the projection lens. It individually controls each beamlet's trajectory and convergence point, enabling precise control that prevents aberrations even when many beamlets are used simultaneously, thus maintaining resolution while achieving high productivity.
3Measurement precision
If the optical column height is increased to accommodate multiple lenses, then beamlet control is improved, but vacuum volume and alignment sensitivity increase
Solution Approach 1:
Multiple beamlet control functions (positioning, focusing) and the projection function are combined in a compact arrangement where the beamlet manipulator array operates in close proximity to the shared projection lens. This merging eliminates the need for a tall optical column with multiple separated lenses, reducing vacuum volume and minimizing alignment sensitivity while maintaining precise beamlet control.
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 enables the generation of a large number of beamlets, achieving smaller critical dimensions and maintaining sufficient wafer throughput, while reducing the complexity and cost of the system and minimizing aberrations.
Implementation Method 1
The projection lens arrangement comprises a first plate having a first array of apertures formed therein, a second plate having a second array of apertures formed therein, and a third plate having a third array of apertures formed therein
Implementation Method 2
projection lens arrangement (10) comprising a first plate having a first array of apertures formed therein, a second plate having a second array of apertures formed therein, and a third plate having a third array of apertures formed therein
Data Source
Figure 1~2
Figure 3~6
Figure 7~10
AI summary
The invention relates to a charged particle multi-beamlet lithographic system for exposing a target (11) using a plurality of beamlets (21). The system comprises a beamlet generator for generating a plurality of beamlets, a beamlet blanker (6) for controllably blanking beamlets; and an array of projection lens systems (10) for projecting unblanked beamlets on to the surface of the target. The beamlet generator comprises at least one charged particle source (1) for generating a charged particle beam, a sub-beam generator (4A) for defining a plurality of sub-beams from the charged particle beam, a sub-beam manipulator array (4B, 5) for influencing the sub-beams; and an aperture array (4C) for defining beamlets from the sub-beams.