Charged Particle Beam Dose Calculation for Writing Time Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional electron beam writing methods require excessive irradiation time due to uniform dose calculation, which is inefficient for miniaturized patterns, as they do not adequately differentiate between doses at figure edges and interior regions, leading to longer writing times.
Innovation Solution
A charged particle beam writing apparatus and method that calculates doses for small, mesh-like regions using different formulas based on whether a shot is at the edge or inside a figure pattern, allowing for reduced irradiation time by adjusting doses accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a uniform dose formula is used for all regions, then the figure edge dose can be controlled to reach the threshold value, but the interior regions receive excessive dose resulting in longer writing time
Solution Approach 1:
The patent divides the writing region into multiple small mesh-like regions and further classifies shots into different types (edge shots, interior shots, boundary shots) based on their position relative to figure patterns. This segmentation allows different dose formulas to be applied to different shot types, resolving the contradiction by enabling precise dose control at figure edges while reducing dose for interior regions where excessive dose is not needed for pattern formation.
Solution Approach 2:
The patent implements local quality by assigning different dose calculation formulas to different spatial locations and shot types. Edge shots use one formula optimized for reaching threshold values at figure boundaries, while interior shots use another formula that provides sufficient but not excessive dose. This localized approach ensures manufacturing precision where needed while improving productivity in regions where high dose is unnecessary.
2Manufacturing precision
If the dose is increased to ensure proper resist development, then pattern accuracy is maintained, but the irradiation time increases excessively
Solution Approach 1:
The patent changes the dose parameter dynamically based on shot type and position. Instead of using a fixed uniform dose, the system calculates different doses for edge shots, interior shots, and boundary shots using distinct formulas. This parameter change ensures that pattern accuracy is maintained at figure edges where threshold values must be reached, while reducing irradiation time by applying lower doses to interior regions where excessive dose does not improve pattern accuracy.
3Manufacturing precision
If conventional dose calculation is used for miniaturized patterns, then the threshold value can be reached at figure edges, but the writing time becomes unacceptably long
Solution Approach 1:
The patent segments the dose calculation process by shot type, implementing separate dose formulas for edge shots, interior shots, and boundary shots. This segmentation allows the system to achieve threshold values at figure edges for miniaturized patterns while avoiding excessive dose application in interior regions, thereby maintaining manufacturing precision while significantly improving writing throughput for miniaturized patterns.
Data Source
AI summary
A charged particle beam writing apparatus includes a dose calculation unit to calculate, for each of a plurality of first small regions made by virtually dividing a writing region of a target object to be mesh-like regions each having a size larger than an influence radius of forward scattering of a charged particle beam, a dose of the charged particle beam shot in a first small region concerned of the plurality of first small regions, by using a dose formula which is different depending on a shot type classified by whether a shot figure formed by the charged particle beam is at an edge of a figure pattern or inside the figure pattern in the first small region concerned, and a writing unit to write, for each of the plurality of first small regions, the figure pattern with a dose calculated by the dose formula.