Pattern Coverage Calculation for Multi-Beam Writing Pixels

Solution Overview

Problem

As semiconductor devices become more densely packed, the reduction in circuit line width increases the computational burden and memory requirements for calculating pattern coverage and dosage in multi-beam writing processes, particularly when pixel sizes decrease, leading to longer calculation times and higher memory usage.

Innovation Solution

A method is introduced to divide the writing region into smaller pixel regions, calculating coverage in larger first pixel regions and then subdividing these into second pixel regions, selecting those approximating the pattern shape based on their center of gravity, and calculating coverage only for these selected regions, thereby reducing memory usage and calculation complexity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If pixel size is reduced to improve resolution and writing accuracy, then manufacturing precision is improved, but calculation time and memory usage increase significantly

Engineering Contradiction:

Improvewriting accuracyVSAvoidcalculation time

Core Design Contradiction:

Manufacturing precisionVSLoss of time

Solution Approach 1:

The writing region is divided into multiple blocks, and within each block, pixels are processed in groups rather than individually. This segmentation allows the system to handle high-resolution patterns while reducing the computational burden by processing smaller subsets of pixels simultaneously.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Adjacent pixels with similar coverage characteristics are merged into representative pixels. By combining multiple pixels into one representative pixel that captures the essential coverage information, the system maintains writing accuracy while significantly reducing the number of calculations required.

Inventive Principle:

Principle #5Merging (Combining)

2Manufacturing precision

If pixel size is reduced to improve resolution and writing accuracy, then manufacturing precision is improved, but memory usage increases significantly

Engineering Contradiction:

Improvewriting accuracyVSAvoidmemory usage

Core Design Contradiction:

Manufacturing precisionVSQuantity of substance

Solution Approach 1:

The writing region is divided into multiple blocks, and within each block, pixels are processed in groups rather than individually. This segmentation allows the system to handle high-resolution patterns while reducing the computational burden by processing smaller subsets of pixels simultaneously.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Adjacent pixels with similar coverage characteristics are merged into representative pixels. By combining multiple pixels into one representative pixel that captures the essential coverage information, the system maintains writing accuracy while significantly reducing the number of calculations required.

Inventive Principle:

Principle #5Merging (Combining)

3Productivity

If multi-beam writing is used to improve throughput, then productivity is improved, but calculation complexity and memory requirements increase

Engineering Contradiction:

ImprovethroughputVSAvoidcalculation complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The writing region is divided into multiple blocks, and within each block, pixels are processed in groups rather than individually. This segmentation allows the system to handle high-resolution patterns while reducing the computational burden by processing smaller subsets of pixels simultaneously.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent implements a unified coverage calculation method that works efficiently for both single-beam and multi-beam writing modes. The same representative pixel approach and block division strategy apply regardless of the number of beams, providing a universal solution that scales with system complexity without requiring fundamentally different algorithms.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS12488959B2Coverage calculating method, charged particle beam writing method, coverage calculating device, charged particle beam writing apparatus, and computer-readable storage medium

Publication Date: 2025.12.02 NUFLARE TECH INC

AI summary

In one embodiment, a coverage calculating method is for calculating a coverage of a pattern in each of pixel regions obtained by dividing a writing region onto which the pattern is to be written by irradiation with a charged particle beam. Each of the pixel regions has a predetermined size. The method includes generating a plurality of first pixel regions by virtually dividing the writing region, the first pixel regions each having a first size, calculating a coverage of a pattern in the first pixel region, generating a plurality of second pixel regions by virtually dividing the first pixel region, the second pixel regions each having a second size smaller than the first size, selecting a second pixel region approximating a pattern shape in the first pixel region, and calculating a coverage in the selected second pixel region.