Optical Metrology for Semiconductor Wafer Dielectric Damage
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Solution Overview
Problem
Conventional optical metrology systems struggle to accurately measure damaged structures on semiconductor wafers, particularly in determining the extent of dielectric damage, which affects the quality of semiconductor fabrication.
Innovation Solution
The method involves directing an incident beam at a damaged structure on a semiconductor wafer to receive a diffracted beam, processing it to determine the profile of undamaged portions, and measuring the amount of dielectric damage using optical metrology, employing techniques such as library-based and regression-based processes to analyze diffraction signals and generate hypothetical profiles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional optical metrology is used to measure the deterministic profile of a structure, then the critical dimension can be determined, but the measurement accuracy deteriorates when stochastic effects such as damaged materials are present
Solution Approach 1:
The patent segments the structure into undamaged portions and damaged portions, allowing separate analysis of each. The optical metrology system measures the deterministic profile of undamaged portions while independently characterizing damaged materials, thereby maintaining measurement accuracy even when damage is present
Solution Approach 2:
The patent introduces new parameters to characterize damaged materials, including damage depth, damage width, and damage concentration. By adding these parameters to the measurement model, the system can accurately represent and measure structures with stochastic damage effects that conventional single-parameter models cannot capture
2Manufacturing precision
If optical metrology is used to determine the profile of a periodic grating, then the quality of fabrication can be evaluated, but the ability to quantify dielectric damage is insufficient
Solution Approach 1:
The patent introduces an intermediary modeling step where measured optical data is compared against a library of simulated diffraction patterns representing various damage scenarios. This intermediary model enables the system to infer damage characteristics that are not directly observable, thereby recovering information that would otherwise be lost
Solution Approach 2:
The patent replaces direct physical inspection methods with optical metrology-based diffraction analysis. By substituting mechanical or visual inspection with optical diffraction measurements and computational modeling, the system can non-destructively quantify dielectric damage while maintaining fabrication quality evaluation
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 precise measurement of damaged structures, allowing for the assessment of dielectric damage and improving the evaluation of semiconductor fabrication quality by providing detailed profiles and damage quantification.
Implementation Method 1
directing an incident beam on the damaged structure. A diffracted beam is received from the damaged structure
Data Source
AI summary
A method of measuring a damaged structure formed on a semiconductor wafer using optical metrology includes directing an incident beam on the damaged structure. A diffracted beam is received from the damaged structure. The received diffracted beam is processed to determine a profile of an undamaged portion of the damaged structure and to measure an amount of dielectric damage of the damaged structure.