Multi-Beam Writing Apparatus Deflection Offset Tracking
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In multi-beam writing techniques for semiconductor devices, defective beams can cause image degradation due to inconsistent irradiation, leading to adjacent pixel columns being irradiated with multiple defective beams, especially when the beam swing back amount and defective beam cycle are consistent, resulting in poor pattern accuracy.
Innovation Solution
A method and apparatus that perform k-th tracking control by deflecting beams to follow stage movement within a rectangular or square irradiation region, with an offset of an integer multiple of the beam pitch, to minimize the number of pixels irradiated by defective beams, using a first deflector for tracking and a second deflector for offsetting the writing position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple beams are used for writing to increase throughput, then writing productivity is improved, but the risk of defective beams causing image degradation increases
Solution Approach 1:
The patent segments the writing process into multiple independent tracking control cycles (k-th tracking control, (k+1)th tracking control, etc.), where each cycle processes a specific set of pixels. By dividing the writing region and processing it in segmented tracking cycles with different swing back amounts, the system can identify and mitigate the impact of defective beams while maintaining overall writing productivity.
Solution Approach 2:
The patent changes the swing back amount parameter between different tracking control cycles. Specifically, it sets the swing back amount in the (k+1)th tracking control to be different from that in the k-th tracking control. This parameter variation ensures that pixels are not consistently irradiated by the same defective beams across cycles, thereby improving pattern accuracy while maintaining multi-beam writing throughput.
2Ease of operation
If the beam swing back amount is set to match the defective beam cycle, then beam positioning is simplified, but adjacent pixel columns are repeatedly irradiated by defective beams
Solution Approach 1:
The patent introduces dynamic adjustment of the swing back amount based on the tracking control cycle number. Instead of using a fixed swing back amount, the system dynamically varies the swing back amount between different k-th tracking controls. This dynamic approach prevents consistent alignment with defective beam cycles while maintaining manageable tracking control operations.
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 reduces the number of pixels irradiated by defective beams, improving pattern accuracy by strategically shifting the beam positions to avoid consistent irradiation patterns, thereby enhancing the writing precision in small regions.
Implementation Method 1
performing a k-th tracking control (k being a natural number) by beam deflection in order to follow movement of a stage
Implementation Method 2
collectively deflecting, during the tracking control, the multiple beams to a position to which a writing position of the each beam is offset by an offset distance of an integer multiple of the size of the beam pitch
Data Source
AI summary
A multi-beam writing method includes performing the k-th tracking control (k being a natural number) by beam deflection in order to follow movement of the stage while collecting each beam of multiple beams, performing a plurality of shots of the multiple beams by the each beam simultaneously shifting in a rectangular or square irradiation region, which is surrounded by the size of the beam pitch and corresponding to the each beam, while performing the k-th tracking control, and returning, after the period of the k-th tracking control has passed, the tracking position to a position which is obtained by adding an offset of an integer multiple of the size of the beam pitch to the tracking starting position of the k-th tracking control where the k-th tracking control started, to be as a starting position of the (k+1)th tracking control.