Lithography Bossung Plot Pattern Matching
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Solution Overview
Problem
Current methods for determining the best focus and exposure settings in lithography tools require complex software and are difficult to integrate into inline Statistical Process Control (SPC) or Automated Process Control (APC) systems, making them costly and inefficient.
Innovation Solution
A method using pattern matching to determine lithography tool process parameters by creating a baseline Bossung plot, selecting a model, applying offset values, and comparing it to inline data to find matching reference plots, thereby simplifying the determination of focus and exposure settings without needing expensive software.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If FEM analysis with Bossung Curve is used to determine best focus and exposure settings, then measurement precision is improved, but device complexity increases due to complicated software code requirements
Solution Approach 1:
The patent creates a reference Bossung plot from measured lithography data and compares it against a library of pre-generated reference Bossung plots with known focus and exposure settings. This copying approach replaces complex automated FEM analysis software with a simpler pattern matching process that achieves the same measurement precision by comparing plotted curves rather than processing raw data through complex algorithms.
Solution Approach 2:
The patent pre-generates a library of reference Bossung plots covering a range of known focus and exposure settings before actual measurement. This preliminary action allows the system to quickly match measured data against pre-computed references, eliminating the need for complex real-time FEM analysis software while maintaining determination accuracy.
2Measurement precision
If expensive automated FEM analysis software is purchased to extract best process conditions, then measurement precision is improved, but loss of substance increases due to high cost
Solution Approach 1:
The patent replaces expensive commercial FEM analysis software with an inexpensive in-house implemented pattern matching system using pre-generated reference Bossung plots. This approach maintains measurement precision while eliminating the need for costly software licenses, directly addressing the financial cost concern.
3Measurement precision
If complex FEM analysis software is used to determine process conditions, then measurement precision is improved, but ease of operation deteriorates due to difficulty of integration into inline SPC or APC systems
Solution Approach 1:
The patent converts measured lithography data into Bossung plots and compares them against reference plots, creating a standardized visual representation that is easily integrated into existing SPC and APC systems. This copying and comparison approach avoids the need for complex FEM analysis software while maintaining measurement precision and improving ease of integration.
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 simplifies the determination of lithography tool process conditions, reduces costs, and allows easy integration into SPC and APC systems, providing a reliable method for fault detection and real-time process monitoring.
Implementation Method 1
The photoresist layer is processed by passing a radiation from an exposure source of a lithography tool through a mask having a pattern
Data Source
AI summary
A method for forming an integrated circuit (IC) is presented. The method includes providing a wafer having a substrate prepared with a photoresist layer. The photoresist layer is processed by passing a radiation from an exposure source of a lithography tool through a mask having a pattern. The process parameters of the lithography tool are determined by performing a pattern matching process. The photoresist layer is developed to transfer the pattern on the mask to the photoresist layer.