Multi-Beam Writing Dose Redistribution for Defective Beam Errors
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Solution Overview
Problem
In multiple beam writing, excessive dose defects in electron beams can cause pattern shape errors due to uncontrolled irradiation, particularly at the ends of patterns, where peripheral beams outside the pattern edges receive unintended doses, making it difficult to share excessive doses effectively.
Innovation Solution
A multi-charged particle beam writing apparatus and method that includes a beam forming mechanism, dose calculation circuit, additional dose allocation, correction circuit, and writing mechanism to allocate and correct excessive doses by distributing them within the pattern area, using a multi-charged particle beam writing apparatus with a beam forming mechanism, dose calculation circuit, additional dose allocation circuit, and correction circuit to adjust dose distributions and correct excessive doses within the writing target pattern.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple beams are used for writing to increase throughput, then productivity is improved, but the risk of defective beams causing excessive dose and pattern shape errors increases
Solution Approach 1:
The system implements feedback control by detecting defective beams through monitoring mechanisms and automatically adjusting the irradiation plan. The dose distribution calculation considers actual beam status and redistributes doses to compensate for defective beams, ensuring reliable pattern formation despite beam failures.
Solution Approach 2:
The system performs preliminary detection of defective beams before writing and pre-calculates the dose distribution taking into account anticipated beam failures. By identifying problematic beams in advance and adjusting the irradiation plan accordingly, the system prevents pattern shape errors before they occur.
2Manufacturing precision
If dose is controlled based on irradiation time, then manufacturing precision is improved, but reliability deteriorates due to difficulty in controlling irradiation time from blanking control failures
Solution Approach 1:
The system changes the control parameter from irradiation time to dose distribution calculation. Instead of relying on precise time control which is vulnerable to blanking failures, the system calculates and adjusts the spatial distribution of doses, redistributing excessive doses from defective beam locations to surrounding areas to maintain pattern accuracy.
3Reliability
If excessive dose from defective beam is shared by peripheral beams, then reliability is improved, but manufacturing precision deteriorates at pattern edges where peripheral beams are located outside the pattern
Solution Approach 1:
The system applies local quality by treating different regions of the pattern differently in the dose redistribution process. For interior regions, excessive dose is shared with peripheral beams, while for edge regions where peripheral beams fall outside the pattern, the system uses alternative compensation strategies such as adjusting doses of nearby interior beams or modifying the dose distribution locally to maintain pattern edge accuracy.
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
Reduces pattern shape errors by effectively managing excessive doses through dose distribution and correction, ensuring precise pattern formation on the target object.
Implementation Method 1
a writing apparatus using multiple beams. Since it is possible for multiple beam writing to apply multiple beams at a time
Implementation Method 2
reduces by an optical system each beam that was not blocked in the blanking process to reduce a mask image
Implementation Method 3
deflects the reduced beam by a deflector to irradiate a desired position on a target object
Data Source
AI summary
A multi-charged particle beam writing apparatus includes a circuit to allocate an additional dose to a position inside a writing target pattern in order to change a first dose distribution by an excessive dose, generated on the target object by applying, in the multi-charged particle beams, an excessive dose defective beam, to a second dose distribution whose center is located inside the writing target pattern and for which beam irradiation canceling out the excessive dose and being in a range of the first dose distribution exists; and a circuit to perform correction by subtracting an increased dose amount, generated at the center of the second dose distribution because of the additional dose being allocated, from a dose with which one of the center of the second dose distribution and a vicinity of the center of the second dose distribution is irradiated.