Resist Deformation Estimation for Lithographic Process Precision

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Solution Overview

Problem

Current lithographic processes face challenges in accurately estimating and managing deformation of resist layers, which affects the precision and reliability of pattern transfer onto substrates, especially at the nanoscale, where features are printed below the classical resolution limit.

Innovation Solution

A computer-implemented method for estimating three-dimensional deformation of resist layers by analyzing characteristics in multiple directions, integrating engineering strain, balancing shear and normal stresses, and adjusting design variables to optimize lithographic processes, thereby improving pattern transfer accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If resist deformation is not accurately estimated, then lithographic process is simpler, but pattern transfer precision deteriorates

Engineering Contradiction:
Improvepattern transfer precisionVSAvoiddeformation estimation complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The deformation estimation is divided into independent directional components (first direction, second direction perpendicular to first, and third direction perpendicular to both). Each direction can be estimated separately using simplified models, then combined to obtain the full 3D deformation. This segmentation reduces computational complexity while maintaining precision.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The method transitions from 2D planar deformation estimation to 3D volumetric deformation estimation by adding a third dimension. The deformation is characterized by displacement vectors in multiple directions, enabling accurate modeling of complex resist layer deformation while maintaining computational efficiency through directional independence.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Manufacturing precision

If multi-directional deformation estimation is performed, then pattern transfer accuracy is improved, but computational time increases

Engineering Contradiction:
Improvepattern transfer accuracyVSAvoidcomputational time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The computational task is segmented into independent directional estimation problems. Each direction (first, second, and third directions) can be processed separately using optimized algorithms, reducing the computational burden compared to a monolithic 3D approach while achieving comprehensive deformation characterization.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The method estimates deformation characteristics in multiple directions (potentially more than strictly necessary) to ensure sufficient accuracy for pattern transfer. By including deformation components in all three spatial directions, the method provides a conservative over-estimation that guarantees precision requirements are met without excessive computational cost.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP3271783B1Methods for determining resist deformation and methods for improving a lithographic process
Publication Date: 2021.04.07 ASML NETHERLANDS BV
  • EP3271783B1 patent drawingFigure 1
  • EP3271783B1 patent drawingFigure 2
  • EP3271783B1 patent drawingFigure 3

AI summary

A method including: obtaining at least a characteristic of deformation of a resist layer in a first direction, as if there were no deformation in any directions perpendicular to the first direction; obtaining at least a characteristic of deformation of the resist layer in a second direction as if there were no deformation in the first direction, the second direction being perpendicular different to from the first direction; and obtaining at least a characteristic of three-dimensional deformation of the resist layer based on the characteristic of the deformation in the first direction and the characteristic of the deformation in the second direction.