Multi Beam Writing Apparatus Defective Beam Dose Distribution
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Solution Overview
Problem
In multi-beam writing processes for semiconductor manufacturing, the presence of defective beams increases the maximum irradiation time, leading to reduced throughput due to the need for complementary exposure and dose modulation, which complicates precise control of beam positions and doses.
Innovation Solution
A charged particle beam writing apparatus and method that calculates and distributes doses among multiple beams to compensate for defective beams by redistributing the dose to nearby beams, ensuring the gravity center of the distributed dose aligns with the intended design grid, thereby minimizing positional deviations and maintaining throughput.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If complementary exposure processing is added to handle defective beams, then the pattern writing completeness is improved, but the maximum irradiation time increases and throughput decreases
Solution Approach 1:
The system performs preliminary detection of defective beams before writing processing, and pre-calculates alternative beam assignments and dose distributions. This allows the system to handle defective beams without adding complementary exposure steps during actual writing, thereby maintaining throughput while ensuring pattern completeness.
Solution Approach 2:
When a defective beam is detected, the system assigns the irradiation task to another functional beam as a copy substitute. The dose and writing parameters are replicated and adjusted for the substitute beam, allowing continuous writing without interruption or additional exposure steps.
2Manufacturing precision
If dose modulation is performed to correct proximity effect and positional deviation, then the manufacturing precision is improved, but the maximum irradiation time increases
Solution Approach 1:
The system dynamically adjusts beam parameters including dose, focus, and position in real-time based on detected beam conditions and target pattern requirements. By optimizing these parameters for each beam-shot combination, the system achieves high dimensional accuracy without requiring extended irradiation times for correction.
Solution Approach 2:
The system replaces physical re-positioning and mechanical adjustments with computational dose modulation and beam parameter control. Through software-based dose distribution optimization, the system corrects proximity effects and positional deviations without increasing irradiation time.
3Ease of operation
If individual blanking mechanisms are arranged for each beam to enable individual control, then the ease of operation is improved, but the device complexity increases
Solution Approach 1:
The system employs a unified blanking control mechanism that can selectively control multiple beams through a single control interface. This universal controller performs the functions of multiple individual blanking mechanisms while reducing hardware complexity and simplifying the control architecture.
Solution Approach 2:
The system combines multiple individual beam control functions into a single integrated blanking control system. By merging the control mechanisms and sharing common control logic, the system maintains individual beam controllability while reducing overall device complexity and component count.
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 allows for efficient pattern writing without increasing the maximum irradiation time, even with defective beams, by redistributing doses among healthy beams, thus enhancing the writing apparatus's throughput and reducing positional deviations in the pattern formed.
Implementation Method 1
a shaping aperture array substrate configured to form multiple charged particle beams by being irradiated with the charged particle beam
Implementation Method 2
a distribution coefficient calculation circuitry configured to calculate, using defective beam information, for each design grid in a plurality of design grids being irradiation positions in design of the multiple charged particle beams, a distribution coefficient for each of three or more beams
Implementation Method 3
a writing mechanism configured to write a pattern on a target object with the multiple charged particle beams in which the dose to irradiate the each design grid in the plurality of design grids has been distributed to each corresponding one of the three or more beams
Data Source
AI summary
A multiple charged particle beam writing apparatus includes a distribution coefficient calculation circuitry to calculate, using defective beam information based on which a defective beam can be identified, for each design grid in a plurality of design grids being irradiation positions in design of multiple charged particle beams, a distribution coefficient for each of three or more beams, for distributing a dose to irradiate a design grid concerned in the plurality of design grids to the three or more beams, excluding the defective beam, whose actual irradiation positions are close to or approximately coincident with the design grid concerned, such that the position of the gravity center of each distributed dose coincides with the position of the design grid concerned and the sum of each distributed dose after distribution coincides with the dose to irradiate the design grid concerned.