Line Edge Roughness Measurement Pre-layer Separation
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Solution Overview
Problem
Existing methods for measuring line-edge-roughness (LER) and line-width-roughness (LWR) in semiconductor fabrication are hindered by the presence of pre-layers, which complicate and distort these measurements, leading to inaccurate estimates of line quality and reliability.
Innovation Solution
A method involving scanning line substructures using a critical dimension scanning electron microscope (CD-SEM) to collect data, sectioning it according to sub-regions with different pre-layers, and computing LER/LWR measures such as RMS, HHCF, and PSD, allowing for pre-layer-dependent analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional LER/LWR measurement methods are used, then measurement process is simple, but measurement precision deteriorates due to pre-layer interference
Solution Approach 1:
The measurement method segments the line image into multiple sections corresponding to different pre-layer regions. Each section is analyzed separately to determine LER/LWR characteristics specific to that pre-layer type, then results are combined to provide an overall measurement that accounts for pre-layer effects without requiring complex additional equipment.
Solution Approach 2:
The patent applies local quality by recognizing that different pre-layer regions have different effects on LER/LWR measurements. Instead of treating the entire line uniformly, the method identifies and analyzes each pre-layer region's specific impact, allowing for localized correction and more accurate overall measurement.
2Adaptability or versatility
If pre-layers are present in the structure, then device functionality is enhanced, but measurement precision of LER/LWR deteriorates
Solution Approach 1:
The method performs preliminary identification and classification of pre-layer regions before conducting LER/LWR measurements. By detecting and mapping pre-layer locations in advance, the measurement process can account for their effects systematically, maintaining accuracy despite the presence of multiple pre-layer types.
Solution Approach 2:
The patent changes the measurement parameters and analysis approach based on the detected pre-layer characteristics. Different measurement parameters or correction factors are applied depending on the type and location of pre-layers, allowing accurate LER/LWR determination across diverse device structures.
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 enables accurate measurement of LER/LWR by accounting for the effects of pre-layers, providing reliable estimates of line quality and improving yield prediction in semiconductor production.
Implementation Method 1
The scanning may comprise receiving image pixels according to the line substructure. In some embodiments, the scanning can be performed using a critical dimension scanning electron microscope (CD-SEM).
Data Source
AI summary
Measurements of line roughness are separated into groups depending upon pre-layers. Image data collected from similar pre-layer types are considered together in order to separate effects of line roughness from distortion of measurements caused by the pre-layers. The resulting line roughness measurements are used to estimate an aspect of line quality.