Electron Beam Drawing Apparatus Rectangle Fracturing Optimization

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Solution Overview

Problem

Conventional electron beam drawing methods for photomasks, such as the variable shaped beam (VSB) method, are limited to drawing rectangles and struggle with curved lines, requiring approximation into trapezoids and increasing the number of rectangles, thereby prolonging the mask drawing time.

Innovation Solution

An electron beam drawing apparatus that reduces the number of rectangles by fracturing graphics into approximate rectangles based on graphic width classification and pattern identification, using a system with a storage unit, accepting unit, graphic width acquiring unit, judging unit, and generating unit to create approximate graphic information for efficient drawing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If curved lines are divided into trapezoids and approximated into rectangles using conventional VSB method, then the drawing can be performed with existing electron beam drawing apparatus, but the number of rectangles increases and mask drawing time becomes long

Engineering Contradiction:
Improvecompatibility with existing VSB apparatusVSAvoidmask drawing time
Core Design Contradiction:
Adaptability or versatilityVSProductivity

Solution Approach 1:

The patent segments the curved line into multiple small rectangular regions along its length. Each rectangle is defined by width and height parameters, and their positions are determined by dividing the curved line into discrete segments. This segmentation approach allows the curved line to be represented as a series of rectangles that can be directly drawn by the VSB apparatus, resolving the contradiction between adaptability to existing systems and drawing efficiency.

Inventive Principle:
Principle #1Segmentation

2Productivity

If the total number of rectangles is reduced through optimized fracturing, then the drawing time is shortened, but the approximation accuracy of curved lines may be affected

Engineering Contradiction:
Improvedrawing timeVSAvoidcurved line approximation accuracy
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent applies partial action by selectively applying different fracturing strategies to different portions of the graphic data. For curved lines, it uses a specialized rectangular segmentation method that achieves adequate approximation with fewer rectangles compared to conventional trapezoid division. This partial application of optimized fracturing to specific graphic elements maintains precision while reducing overall drawing time.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The patent changes the parameters used in fracturing by representing curved lines as rectangles with specific width and height parameters rather than using traditional trapezoid coordinates. This parameter transformation allows for more efficient representation of curved lines, reducing the total number of rectangles needed while maintaining visual fidelity through optimized parameter selection.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2876667B1Electron beam drawing apparatus, electron beam drawing method, and storage medium
Publication Date: 2019.07.31 NIPPON CONTROL SYST CORP
  • EP2876667B1 patent drawingFigure 1
  • EP2876667B1 patent drawingFigure 2
  • EP2876667B1 patent drawingFigure 3

AI summary

In order to solve conventional problems that the total number of rectangles at the time of fracturing is large and the drawing time is long, an electron beam drawing apparatus includes: an accepting unit that accepts input graphic information, which is information representing at least one graphic; a graphic width acquiring unit that acquires a width of each of the at least one graphic represented by the input graphic information; a generating unit that generates approximate graphic information representing at least one approximate graphic, which is a graphic configured by at least one rectangle matching the width of the graphic, and is a graphic that approximates each of the at least one graphic represented by the input graphic information; and a drawing unit that draws the at least one approximate graphic represented by the approximate graphic information generated by the generating unit. Accordingly, it is possible to reduce the total number of rectangles at the time of fracturing, and to shorten the drawing time.