FinFET Electrical Characterization via Hall Effect Probe
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Solution Overview
Problem
Existing methods for inline characterization of finFETs are imprecise and often destructive, struggling to accurately measure the electrical properties of increasingly small finFETs due to limitations in optical, X-ray, and microscopy techniques.
Innovation Solution
The method involves applying an electrical current along the length of finFETs with a perpendicular magnetic field at a low angle to concentrate electron flow towards the upper portion, allowing for precise electrical characterization without damaging the devices, using Hall Effect phenomena to focus current flow and varying source/drain voltage for detailed analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If standard inline characterization methods (optical, X-ray) are used, then measurement can be performed non-destructively, but measurement precision deteriorates due to small finFET dimensions being fractions of illumination wavelengths
Solution Approach 1:
The patent replaces optical and X-ray illumination-based measurement systems with an electrical measurement system using a probe card and Hall effect sensors. This substitution allows direct electrical characterization of finFETs without the diffraction limits that plague optical methods, achieving precise measurements of sub-10nm features through electrical properties rather than optical imaging.
Solution Approach 2:
The patent introduces a probe card with specifically designed contact structures as an intermediary between the measurement system and the finFET. This probe card includes contact pads and sensing elements that enable direct electrical access to the finFET, serving as a mediator that bridges the gap between the external measurement system and the nanoscale device under test.
2Measurement precision
If TEM is used for electrical characterization, then measurement precision can be high, but the finFET is destroyed
Solution Approach 1:
The patent employs a Hall effect measurement technique that uses the finFET's own current-carrying capability to generate the signal for measurement. By applying a magnetic field perpendicular to the current flow in the fin, the Hall voltage arises naturally from the device's operation, eliminating the need for destructive cross-sectional preparation and enabling repeated non-destructive measurements on the same device.
3Loss of information
If CD-AFM is used, then topographical information can be obtained, but only small regions of one or a few finFETs can be scanned
Solution Approach 1:
The probe card design incorporates multiple contact pads and sensing elements that can simultaneously or sequentially measure multiple finFETs across a larger area. The electrical characterization method is universally applicable to different finFET instances and configurations, allowing comprehensive statistical analysis rather than limited single-device measurement.
4Manufacturing precision
If Ellipsometry and Scatterometry are used, then measurement can be performed, but precision is limited by the very small fraction of device sizes to irradiation wavelengths
Solution Approach 1:
The patent replaces wavelength-dependent optical measurement systems (ellipsometry and scatterometry) with electrical measurement systems that are not constrained by diffraction limits. The electrical properties of the finFET can be measured directly with high precision regardless of the sub-wavelength dimensions, as electrical signals can resolve features much smaller than the wavelength of light used in optical techniques.
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 non-destructive, precise characterization of finFETs by concentrating electron flow in the upper region, providing accurate resistance and conductance measurements, and is applicable across various technology nodes and industrial applications.
Implementation Method 1
The application of a perpendicular magnetic field at a relatively low angle with respect to the wafer surface such that Lorentz forces force the electron flow towards the upper area of the finFET
Implementation Method 2
using Hall Effect phenomena to focus current flow
Data Source
AI summary
A method of proving inline characterization of electrical properties of a fin-shaped field effect transistor (finFET) is provided. Embodiments include applying an electrical current along a length of at least one fin of a finFET disposed over a wafer surface; generating a magnetic field across a width of the at least one fin, wherein the magnetic field is perpendicular in direction to the electrical current; and detecting electron flow concentrated at an upper portion of the at least one fin.