Diamond NV Center Probe for Non-Destructive Semiconductor Metrology
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Solution Overview
Problem
Current metrology solutions, such as e-beam based methods and scanning probe microscopy, are inadequate for non-destructively measuring and characterizing conductive features in semiconductor materials, particularly in next-generation devices like finFETs and 3D NANDs, due to limitations in vertical dimension measurement and compatibility with certain mechanical properties.
Innovation Solution
A metrology device employing a diamond tip with nitrogen-vacancy (NV) centers, a scanning mechanism, and a signal processor to analyze fluorescent light emitted in response to photon radiation, allowing for precise determination of conductive feature dimensions and material properties using magnetic fields and Eddy currents induced by varying frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If e-beam based metrology solutions (CD-SEM) are used, then measurement capability is provided, but the method is damaging and has limitations for metrology in vertical dimensions
Solution Approach 1:
The patent replaces the e-beam based metrology system with a scanning probe microscopy system that uses mechanical scanning and optical detection. The probe mechanically scans the sample surface while optical detectors measure fluorescent light emission, eliminating the damaging e-beam interaction and enabling non-destructive vertical dimension measurement.
Solution Approach 2:
The patent utilizes the photoluminescence phase transition of nitrogen-vacancy centers in diamond when excited by laser radiation. The NV centers emit fluorescent light whose intensity and characteristics change in response to the sample's mechanical and electrical properties, enabling non-contact measurement of vertical dimensions without damaging the sample.
2Object-affected harmful factors
If subsurface scanning probe microscopy (SSPM) is used, then non-destructive measurement is achieved, but it is not applicable when mechanical properties of features are comparable with substrate
Solution Approach 1:
The patent enhances the SSPM probe with multi-functionality by integrating nitrogen-vacancy center detection capable of sensing both mechanical properties (vertical dimensions) and electrical properties (conductivity, Eddy currents). This universal probe can distinguish between features with comparable mechanical properties to the substrate by detecting their unique electrical signatures through fluorescent light modulation.
Solution Approach 2:
The patent changes the detection parameter from purely mechanical (deflection) to include electrical properties by measuring the fluorescent light emission characteristics of NV centers. The fluorescent signal modulates in response to both mechanical deformation and electrical conductivity, allowing differentiation of features based on their electrical properties even when mechanical properties are similar.
3Measurement precision
If diamond tip with NV centers is used, then non-destructive measurement of conductive features is enabled, but device complexity increases
Solution Approach 1:
The patent merges the scanning probe microscopy mechanism with nitrogen-vacancy center detection and optical detection systems into a unified instrument. The probe combines mechanical scanning, optical excitation of NV centers, and fluorescent detection in a single integrated system, reducing overall complexity compared to using separate specialized systems for different measurement types.
Solution Approach 2:
The nitrogen-vacancy centers in the diamond probe act as an intermediary between the mechanical probe and the sample's electrical properties. The NV centers convert electrical field interactions into optical signals (fluorescent light modulation), which can then be detected optically. This intermediary conversion enables non-destructive electrical property measurement without requiring direct electrical contact or complex electrical detection systems.
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
Enables accurate, non-destructive measurement of lateral and vertical dimensions, as well as material properties, with enhanced sensitivity and robustness, suitable for complex semiconductor structures where traditional methods fail.
Implementation Method 1
a radiation source to irradiate the tip with photon radiation to excite the tip to emit fluorescent light
Implementation Method 2
irradiating the tip with photon radiation to excite the tip to emit fluorescent light
Implementation Method 3
magnetic fields and Eddy currents induced by varying frequencies
Implementation Method 4
magnetic fields and Eddy currents induced by varying frequencies
Data Source
AI summary
A metrology device for determining metrological characteristics of a sample is described that includes a probe, a scanning mechanism, a radiation source, an optical sensor and a signal processor. In operation the scanning mechanism displaces the probe relative to the sample, along a surface of the sample. The probe has a diamond tip with one or more nitrogen-vacancy centers and is irradiated by the radiation source with photon radiation to excite the diamond tip to emit fluorescent light. The optical sensor provides a sense signal indicative of an intensity of the emitted fluorescent light and the signal processor processes the sense signal to compute at least one characteristic of a feature present in the sample.