Trench Sidewall SIMS Profiling for Lateral Dopant Mapping
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Solution Overview
Problem
Current methods for determining dopant levels in high aspect ratio semiconductor structures, such as Adam Probe Tomography (APT) and Secondary Ion Mass Spectrometry (SIMS), suffer from high detection limits, low mass resolution, high expense, and high processing times, making it difficult to accurately measure dopant concentration and distribution in 3-D structures.
Innovation Solution
A method involving precision micro-cleaving and low-energy SIMS beam profiling is used to determine dopant characteristics by directing the beam perpendicular to the sidewall of high aspect ratio trenches, combined with a two-step data collection methodology using 1.5D SIMS for dopant dose and lateral SIMS for distribution, and applying depth and concentration calibrations to achieve accurate dopant quantification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If Adam Probe Tomography (APT) is used to measure dopant levels, then measurement capability is provided, but detection limits are high, mass resolution is low, expense is high, and processing time is high
Solution Approach 1:
The patent extracts the dopant measurement function from the complex APT system and implements it through a simplified SIMS-based methodology with precision micro-cleaving, achieving the same measurement capability with reduced processing time and cost
Solution Approach 2:
The patent changes the measurement parameters by using secondary ion mass spectrometry with specific energy settings and cleaving angles to optimize dopant detection, achieving high precision measurements without the time and cost penalties of APT
2Measurement precision
If Secondary Ion Mass Spectrometry (SIMS) is used for dose detection, then detection capability is provided, but measurement capability relative to 3-D structure dimensions is limited
Solution Approach 1:
The patent introduces a spatial dimension by performing precision micro-cleaving to expose trench sidewalls, enabling lateral SIMS measurements that provide dopant distribution information across 3-D structures rather than just vertical depth profiles
Solution Approach 2:
The patent segments the measurement process into two distinct steps: 1.5D SIMS for vertical depth profiling and lateral SIMS for horizontal distribution mapping, allowing comprehensive 3-D characterization that overcomes the limitations of conventional SIMS
3Quantity of substance
If conventional SIMS approaches are used, then dopant dose measurement is provided, but lateral dopant distribution measurement in high aspect ratio trenches is difficult
Solution Approach 1:
The patent performs preliminary micro-cleaving to expose the trench sidewalls before SIMS measurement, creating an accessible surface for lateral beam profiling that enables precise measurement of dopant distribution in high aspect ratio structures
Solution Approach 2:
The patent employs dynamic beam profiling where the SIMS beam is scanned laterally across the exposed sidewall surface, enabling measurement of dopant concentration gradients and distribution patterns that are critical for high aspect ratio trench characterization
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 provides precise and efficient measurement of dopant concentration and distribution in trench sidewalls, overcoming the limitations of conventional methods by achieving high resolution and cost-effectiveness.
Implementation Method 1
directing a spectrometry beam into the sidewall of the first structure to determine a dopant characteristic of the first structure
Implementation Method 2
Secondary ion mass spectrometry (SIMS) is another approach used for dose detection
Data Source
AI summary
Disclosed herein are approaches for measuring lateral dopant concentration and distribution in high aspect radio trench structures. In one approach, a method may include providing a substrate including a plurality of alternating vertical structures and trenches, and removing a portion of the substrate to expose a sidewall of the first vertical structure of the plurality of structures. The method may further include directing a spectrometry beam into the sidewall of the first vertical structure to determine a dopant characteristic of the first vertical structure, wherein the spectrometry beam is delivered perpendicular to a plane defined by the sidewall of the first vertical structure.