Multi-Beam Exposure Grid Segmentation for Reduced Processing Time

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Solution Overview

Problem

Conventional multi-beam exposure methods are inefficient as they expose the entire substrate surface, including areas not intended for exposure, leading to increased processing time and data transfer overhead, despite maintaining high accuracy in structure definition.

Innovation Solution

The method restricts exposure to predefined cluster areas on the substrate surface, with exposure positions arranged within these areas and separated by dormant spaces, allowing for reduced processing time while maintaining accuracy through dose adjustments at nominal exposure positions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If conventional multi-beam exposure methods expose the entire substrate surface, then complete coverage is achieved, but processing time and data transfer overhead increase

Engineering Contradiction:
Improveprocessing timeVSAvoidexposed area
Core Design Contradiction:
Loss of timeVSArea of stationary object

Solution Approach 1:

The substrate surface is divided into multiple cluster areas with predefined exposure positions, separating the exposure region from non-exposure regions. This segmentation allows the system to process only relevant areas, reducing overall processing time while maintaining complete coverage where needed.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the substrate are treated differently: cluster areas receive exposure with multiple beamlets, while non-cluster areas are skipped. This local quality approach optimizes processing by applying exposure only where structures need to be formed, eliminating waste of time on irrelevant areas.

Inventive Principle:
Principle #3Local quality

2Manufacturing precision

If exposure positions are densely arranged to maintain accuracy, then structure definition precision is improved, but data transfer requirements increase

Engineering Contradiction:
Improvestructure definition accuracyVSAvoiddata transfer volume
Core Design Contradiction:
Manufacturing precisionVSQuantity of substance

Solution Approach 1:

Cluster areas and exposure positions are predefined before the exposure process begins. This preliminary action allows the system to prepare exposure patterns in advance, reducing real-time data transfer requirements while maintaining precise structure definition through pre-calculated beamlet assignments.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

Multiple beamlets are assigned to each exposure position within cluster areas, providing redundant coverage that ensures high precision structure definition. This partial excessive action maintains manufacturing precision while the predefined nature of cluster areas limits the overall data volume required.

Inventive Principle:
Principle #16Partial or excessive action

3Productivity

If the pattern image width is increased to cover entire stripes, then coverage efficiency improves, but positioning precision for specific exposure spots may be compromised

Engineering Contradiction:
Improvecoverage efficiencyVSAvoidexposure spot positioning accuracy
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The pattern image is segmented into multiple beamlets that collectively cover the stripe width. Each beamlet can be independently controlled and positioned, allowing the system to maintain wide coverage for efficiency while preserving precise positioning for individual exposure spots through selective beamlet activation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system dynamically controls the activation and positioning of individual beamlets within the pattern image. This dynamic control allows the wide pattern image to cover entire stripes efficiently while maintaining precise exposure spot positioning by selectively activating only the necessary beamlets for each exposure position.

Inventive Principle:
Principle #15Dynamics

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 significantly reduces processing time and data requirements while ensuring high accuracy and positional correction, particularly effective in scenarios with overlapping aperture images or specific target shapes.

Implementation Method 1

a beam formed of electrically charged particles, in particular electrons or ions

Methodology Applied
Scientific EffectCharged particle beam: Electron Beam

Implementation Method 2

providing a pattern definition device having a plurality of apertures transparent to said radiation, illuminating said pattern definition device by means of an illuminating wide beam, which traverses the pattern definition device through said apertures thus forming a patterned beam consisting of a corresponding plurality of beamlets

Methodology Applied
Scientific EffectAperture transmission: Filter (optical)

Implementation Method 3

forming said patterned beam into a pattern image on the location of the target, said pattern image comprising the images of at least part of the plurality of apertures

Methodology Applied
Scientific EffectBeam projection: Lens

Implementation Method 4

generating a relative movement between said target and the pattern definition device producing a movement of said pattern image on the target according to a path corresponding to said stripes

Methodology Applied
Scientific EffectRelative motion:

Data Source

PatentEP3460825B1Method for irradiating a target using restricted placement grids
Publication Date: 2020.02.19 IMS NANOFABTION
  • EP3460825B1 patent drawingFigure 1
  • EP3460825B1 patent drawingFigure 2
  • EP3460825B1 patent drawingFigure 3~4

AI summary

A method for irradiating a target with a beam of energetic electrically charged particles, wherein the target comprises an exposure region where an exposure by said beam is to be performed, and the exposure of a desired pattern is done employing a multitude of exposure positions (px2') on the target. Each exposure position represents the location of one of a multitude of exposure spots of uniform size and shape, with each exposure spot covering at least one pattern pixel of the desired pattern. The exposure positions are located within a number of mutually separate cluster areas (L4) which are defined at respective fixed locations on the target. In each cluster area the exposure position (px2') are within a given neighboring distance (ex, ey) to a next neighboring exposure position, while the cluster areas are separated from each other by spaces (LV) free of exposure positions, which space has a width (vx, vy) which is at least the double of the neighboring distance (ex, ey).