Multi-Beam Deflection for Writing Accuracy and Throughput
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Solution Overview
Problem
In multi-beam writing, the accuracy differences between charged particle beams result in varying writing errors across inter-beam pitch regions, leading to decreased throughput due to the need for settling and idling times during beam deflection control.
Innovation Solution
A method and apparatus where the main deflection position of multiple beams follows the stage movement, and the sub deflection position is shifted to straddle rectangular regions, allowing each beam to apply shots to different positions within these regions, thereby increasing the number of beams used to write each inter-beam pitch region without increasing throughput degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the main deflector shifts the inter-beam pitch region to another region to irradiate with more different beams, then writing accuracy improves, but throughput decreases due to settling time and idling time for control
Solution Approach 1:
The sub deflector is positioned and configured in advance to enable beam shifting within the inter-beam pitch region without requiring main deflector repositioning. This preliminary arrangement of the sub deflector allows continuous writing operations without settling time losses that would occur with main deflector shifts.
Solution Approach 2:
The deflection function is segmented between two independent deflectors: the main deflector responsible for inter-beam pitch region positioning and the sub deflector responsible for intra-region beam shifting. This segmentation allows the sub deflector to handle fine-positioning adjustments without triggering settling time requirements associated with the main deflector.
2Manufacturing precision
If each inter-beam pitch region is written with many different beams to equalize writing errors, then writing accuracy improves, but the number of tracking cycles increases leading to more settling and idling times
Solution Approach 1:
Multiple beams are pre-configured to straddle the inter-beam pitch region through sub deflector positioning. This preliminary arrangement ensures that when writing operations commence, multiple beams are already positioned to cover the region, eliminating the need for multiple tracking cycles with associated settling and idling times.
Solution Approach 2:
The sub deflector enables continuous beam shifting within the inter-beam pitch region during a single tracking cycle, maintaining continuous useful writing action. This avoids the interruption and time loss that would occur with multiple discrete tracking cycles required by conventional approaches.
3Manufacturing precision
If the sub deflector shifts beams to straddle rectangular regions with multiple beams applying shots to different positions, then writing errors are averaged across beams, but deflection control complexity increases
Solution Approach 1:
The deflection control is segmented into two independent control systems: main deflector control for region positioning and sub deflector control for beam distribution within regions. This segmentation simplifies the overall control complexity by dividing it into two manageable, independent control tasks rather than one complex control system.
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 effectively averages writing errors across multiple beams while maintaining or improving throughput by reducing the impact of settling and idling times during beam deflection.
Implementation Method 1
a first deflector configured to perform a tracking operation by shifting a main deflection position of the multiple beams in a direction of movement of the stage so that the main deflection position of the multiple beams follows the movement of the stage
Implementation Method 2
a second deflector configured to shift a sub deflection position of the multiple beams during the tracking operation... each beam of the multiple beams straddles rectangular regions in a plurality of rectangular regions obtained by dividing a writing region of a target object into meshes by a size of a pitch between beams of the multiple beams
Implementation Method 3
the electron beam writing technique... is used for writing or 'drawing' a mask pattern on a mask blank with electron beams
Data Source
AI summary
A multiple charged particle writing method includes performing a tracking operation by shifting the main deflection position of multiple beams using charged particle beams in the direction of stage movement so that the main deflection position of the multiple beams follows the stage movement while a predetermined number of beam shots of the multiple beams are performed, and shifting the sub deflection position of the multiple beams so that each beam of the multiple beams straddles rectangular regions among plural rectangular regions obtained by dividing a writing region of a target object into meshes by the pitch size between beams of the multiple beams, and the each beam is applied to a different position in each of the rectangular regions straddled, and applying a predetermined number of shots per beam using plural beams in the multiple beams to each of the plural rectangular regions, during the tracking operation.