Neural Network Mask Generation for Reticle Enhancement

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Solution Overview

Problem

Current reticle enhancement technologies face challenges in efficiently producing masks with high dose margin and resilience to manufacturing variation, particularly with smaller feature sizes and complex geometries, leading to issues with critical dimension uniformity and line-edge roughness.

Innovation Solution

The method involves generating a Continuous Tone Mask (CTM) and Quantized Tone Mask (QTM) using a trained neural network, allowing for optimized mask creation across large sections of the mask layer, reducing stitching artifacts, and employing Function Sample Arrays to represent smooth functions, enabling efficient computation and improved manufacturability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional reticle enhancement technologies are used to produce masks with high dose margin and resilience to manufacturing variation, then manufacturing precision is improved, but device complexity increases due to smaller feature sizes and complex geometries

Engineering Contradiction:
Improvecritical dimension uniformityVSAvoidmask geometry complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The mask design is divided into multiple tiles that can be processed independently. Each tile represents a manageable section of the overall mask pattern, allowing complex geometries to be handled in smaller, more tractable units while maintaining overall pattern integrity and manufacturing precision

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transforms the mask design from binary (present/absent) to continuous tone values, enabling gradual transitions in material density or thickness. This parameter transformation allows for smoother geometries that reduce manufacturing variation while maintaining design flexibility for complex features

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If conventional reticle enhancement technologies are used to produce masks with high dose margin and resilience to manufacturing variation, then manufacturing precision is improved, but line-edge roughness increases

Engineering Contradiction:
Improvecritical dimension uniformityVSAvoidline-edge roughness
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

By transitioning from binary mask patterns to continuous tone patterns, the invention enables gradual transitions in material properties. This parameter transformation smooths edge transitions and reduces abrupt changes that cause line-edge roughness, while still achieving the desired critical dimension uniformity through controlled tone variations

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The continuous tone approach allows different regions of the mask to have locally optimized properties. Areas requiring high precision can have smoother, more gradual tone transitions, while other areas can be optimized for different manufacturing constraints, thereby reducing overall line-edge roughness while maintaining critical dimension uniformity

Inventive Principle:
Principle #3Local quality

3Productivity

If neural networks are used to generate optimized masks across large sections, then productivity is improved, but memory requirements increase

Engineering Contradiction:
Improvemask production efficiencyVSAvoidmemory requirements
Core Design Contradiction:
ProductivityVSQuantity of substance

Solution Approach 1:

The large mask design is divided into smaller tiles that can be processed independently by the neural network. This segmentation reduces the memory footprint required for each neural network operation while maintaining the ability to generate optimized masks across the entire large section through systematic processing of individual tiles

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The neural network is trained to generate optimized patterns for local tile regions rather than requiring the entire large mask section to be processed simultaneously. This local processing approach reduces memory requirements by focusing computational resources on smaller, manageable regions while still achieving overall productivity improvement through automated generation

Inventive Principle:
Principle #3Local quality

Data Source

PatentUS20240086607A1Modeling of a design in reticle enhancement technology
Publication Date: 2024.03.14 D2S INC
  • US20240086607A1 patent drawing
  • US20240086607A1 patent drawing
  • US20240086607A1 patent drawing

AI summary

Methods and systems for reticle enhancement technology (RET) include inputting a target wafer pattern, where the target wafer pattern spans an entire design area. The entire design area is divided into a plurality of tiles, each tile having a halo region surrounding the tile. An optimized mask is calculated, wherein the optimized mask is generated by a first trained neural network using the target wafer patter. The calculating is performed for each tile in the plurality of tiles including its halo region.