Corona-Biased SHG Metrology for Semiconductor Interface Leakage

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Solution Overview

Problem

Existing SHG techniques for semiconductor manufacturing and metrology face challenges in effectively utilizing magnetic field and induced voltage biases to characterize interfacial properties without contact probes, and there is a need for improved methods to measure interfacial leakage current and carrier injection energies.

Innovation Solution

The use of corona discharge sources and non-contact biasing techniques, such as capacitive and inductive coupling, to induce voltage fields across semiconductor interfaces, combined with SHG measurement systems, allows for synchronized data collection and characterization of interfacial properties without direct electrical contact.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If contact probes are used for SHG measurement, then electrical contact is established, but device complexity and potential damage to the sample increase

Engineering Contradiction:

Improvemeasurement reliabilityVSAvoidprobe contact complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces mechanical contact probes with a non-contact corona discharge source that delivers electrical charge through plasma. This substitution eliminates the need for physical contact between measurement probes and the sample surface, reducing device complexity while maintaining measurement capability through field-based charge deposition

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces an intermediary corona discharge plasma field as a mediator between the measurement system and the sample. Instead of direct contact, electrical charge is transferred through the plasma intermediary, enabling non-contact measurement while still achieving the desired electrical biasing effect on the sample

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If traditional SHG techniques are used, then measurement can be performed, but sensitivity to surface and interface properties in centrosymmetric materials is limited

Engineering Contradiction:

Improvesurface and interface property sensitivityVSAvoidapplicability to centrosymmetric materials

Core Design Contradiction:

Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent changes the measurement parameter by introducing electrical charge deposition through corona discharge, creating a field-biased SHG measurement system. This parameter change enables detection of interface properties in centrosymmetric materials by modifying the electrical state of the sample surface and interfaces, thereby enhancing SHG signal sensitivity

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent applies preliminary action by depositing electrical charge on the sample surface through corona discharge before performing the SHG measurement. This preliminary charge deposition creates the necessary electric field conditions to enhance sensitivity to surface and interface properties, preparing the sample in an optimized state for measurement

Inventive Principle:

Principle #10Preliminary action

3Ease of operation

If field-biased SHG with corona discharge is used, then non-contact characterization is achieved, but additional equipment complexity is introduced

Engineering Contradiction:

Improvenon-contact operationVSAvoidcorona discharge equipment

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The patent achieves multi-functionality by designing a system where the corona discharge source serves multiple purposes: it deposits electrical charge for field biasing, enables non-contact measurement, and provides electrical control over the sample state. This universal approach consolidates multiple functions into a single integrated system, reducing overall complexity despite the advanced nature of the corona discharge equipment

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 and noise-reduced SHG measurements, providing insights into interfacial leakage currents and carrier injection energies, similar to DC biased measurements, while avoiding contact probes and enhancing measurement precision.

Implementation Method 1

depositing different amounts of electrical charge to a top side of the sample using a corona gun

Methodology Applied

Scientific EffectCorona discharge: Corona Discharge

Implementation Method 2

detecting using an optical detector, a Second Harmonic Generation (SHG) effect signal generated by the probing radiation

Methodology Applied

Scientific EffectSecond Harmonic Generation: Second Harmonic Generation

Data Source

PatentUS12601778B2Field-biased nonlinear optical metrology using corona discharge source

Publication Date: 2026.04.14 FEMTOMETRIX INC

AI summary

Various approaches can be used to interrogate a surface such as a surface of a layered semiconductor structure on a semiconductor wafer. Certain approaches employ Second Harmonic Generation while other utilize four wave-mixing or multi-wave mixing. Corona discharge may be applied to the sample to provide additional information. Some approaches involve determining current flow from a sample illuminated with radiation.