Convolutional Neural Network for Mask Resist Pattern Prediction

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

In lithography for integrated circuit manufacturing, the circuit pattern on the mask does not always match the post-patterning pattern due to various factors, making it difficult to accurately predict the resist pattern and detect defects without complex and imprecise simulations.

Innovation Solution

A convolutional neural network (CNN) is used to estimate the threshold for light intensity in the optical image, allowing for precise simulation of the resist pattern and post-patterning pattern, and detection of defects without requiring manual setting of thresholds or complex analytical methods.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional simulation methods are used to evaluate the resist pattern, then the circuit pattern of the mask can be designed, but the prediction accuracy of the resist pattern is low and the simulation process is complex

Engineering Contradiction:
Improveprediction accuracy of resist patternVSAvoidcomplexity of simulation process
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces conventional mechanical/optical simulation methods with a machine learning model (neural network). The system inputs optical image data and resist condition data, and the neural network automatically outputs the resist pattern without requiring complex physical simulation calculations. This substitution of the simulation mechanism with an intelligent algorithm resolves the contradiction by providing high accuracy through learned patterns while eliminating the complexity of traditional simulation processes.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If manual threshold setting is used in simulation, then the simulation can be performed, but the precision of resist pattern prediction is insufficient

Engineering Contradiction:
Improveprecision of resist pattern predictionVSAvoidease of threshold setting
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The system employs self-service through automatic threshold determination. The neural network model automatically learns and determines the optimal threshold values for resist pattern prediction by training on input data (optical images and resist conditions). This eliminates the need for manual threshold setting by operators, simultaneously improving prediction precision through data-driven optimization while greatly simplifying the operation process. The system serves itself by automatically configuring parameters that were previously required manual intervention.

Inventive Principle:
Principle #25Self-service

3Manufacturing precision

If extensive simulations are performed to ensure accuracy, then the mask design can be optimized, but the design efficiency is reduced

Engineering Contradiction:
Improveaccuracy of mask designVSAvoiddesign efficiency of mask
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The system performs preliminary action by pre-training the neural network model with extensive simulation data and resist condition information before actual mask design work. Once trained, the model can rapidly predict resist patterns for new mask designs without requiring extensive repeated simulations. This preliminary preparation of the intelligence model enables high accuracy in subsequent design work while dramatically improving design efficiency, as the model instantly applies learned knowledge rather than performing computationally intensive simulations for each design iteration.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentUS10282509B2Non-transitory computer readable storage medium, mask evaluation method and inspection apparatus
Publication Date: 2019.05.07 KIOXIA CORP
  • US10282509B2 patent drawing
  • US10282509B2 patent drawing
  • US10282509B2 patent drawing

AI summary

A non-transitory computer readable storage medium according to an embodiment stores a mask evaluation program evaluating a mask used to manufacture an integrated circuit device. The program causes a computer to realize a convolutional neural network. The convolutional neural network output a calculated value of second data when first data is input. The first data corresponds to a circuit pattern of the mask. The second data corresponds to a pattern formed by the mask. The convolutional neural network has a filter and a weighting coefficient learned to reduce an error of the calculated value and an actual measured value of the second data by using the first data and the actual measured value of the second data.