Substrate Stack Configuration Optimization for Lithography
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Solution Overview
Problem
Current lithographic projection technologies face challenges in accurately reproducing patterns with dimensions smaller than the classical resolution limit, particularly in low-k1 lithography, where achieving precise electrical functionality and performance is difficult due to limitations in projection optics and design layouts.
Innovation Solution
A method is developed to determine an optimum stack configuration for substrates undergoing patterning processes by using measurement data, a substrate model, and an iterative process to fit model parameters, predicting stack characteristics such as thickness and critical dimensions, and optimizing the stack configuration using a hardware computer system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional lithographic projection is used, then manufacturing process is simple, but manufacturing precision deteriorates for dimensions smaller than classical resolution limit
Solution Approach 1:
The patent changes physical parameters of the stack configuration (layer thicknesses, material properties, structural dimensions) to optimize pattern reproduction. By systematically varying these parameters and measuring their effects on printed pattern accuracy, the method achieves improved manufacturing precision for sub-resolution features while managing stack configuration complexity through controlled parameter exploration.
2Manufacturing precision
If stack configuration is optimized for precise pattern reproduction, then manufacturing precision improves, but measurement and control difficulty increases
Solution Approach 1:
The patent implements a feedback loop where measurement data from printed patterns is fed back to update the stack configuration model. The method measures actual pattern dimensions and compares them with predicted values, then uses this feedback to refine the stack configuration parameters. This iterative feedback process enables precise control of complex stack configurations while improving measurement accuracy through model-based compensation.
Solution Approach 2:
The patent performs preliminary measurements and model updates before final pattern printing. By measuring stack configuration characteristics in advance and updating the model beforehand, the method prepares optimized parameters that simplify subsequent measurement and control operations, reducing the difficulty of detecting and measuring complex configurations during actual manufacturing.
3Measurement precision
If model parameters are fitted to measurement data, then prediction accuracy improves, but computational time increases
Solution Approach 1:
The patent applies partial fitting by selecting only the most influential model parameters for adjustment based on sensitivity analysis. Instead of fitting all parameters exhaustively, the method identifies and optimizes only those parameters that have the greatest impact on prediction accuracy. This partial action approach achieves sufficient prediction accuracy while significantly reducing computational time and resource requirements.
Data Source
AI summary
A method for determining a stack configuration for a substrate subjected to a patterning process. The method includes obtaining (i) measurement data of a stack configuration with location information on a printed substrate, (ii) a substrate model configured to predict a stack characteristic based on a location of the substrate, and (iii) a stack map including a plurality of stack configurations based on the substrate model. The method iteratively determines values of model parameters of the substrate model based on a fitting between the measurement data and the plurality of stack configurations of the stack map, and predicts an optimum stack configuration at a particular location based on the substrate model using the values of the model parameters.