Automated SEM Nanoprobe Tool for Transistor-Level Defect Detection

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Solution Overview

Problem

Current defect inspection methods for semiconductor wafers, such as optical inspection and scanning electron microscopes, are inadequate in detecting subtle electrical defects like grain boundaries and transient voltage contrast defects due to limitations in spatial resolution and sensitivity.

Innovation Solution

A charged particle beam system that directs a primary beam of energetic particles onto a sample, detects secondary charged particles, and measures their transient behavior using a fast detector with sub-10 ns time resolution, allowing for characterization of surface features by comparing measured transient behavior to reference patterns.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If optical inspection methods are used, then inspection speed is improved, but spatial resolution and detection sensitivity deteriorate

Engineering Contradiction:

Improveinspection speedVSAvoidspatial resolution

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The patent combines optical inspection capabilities with electron beam detection capabilities into a single inspection system. The system integrates an optical detector for fast inspection and an electron beam detector for high-resolution defect detection, allowing the system to achieve both high inspection speed and high spatial resolution by merging two different detection methodologies.

Inventive Principle:

Principle #5Merging (Combining)

2Measurement precision

If SEM inspection is used, then spatial resolution is improved, but detection sensitivity to certain electrical defects deteriorates

Engineering Contradiction:

Improvespatial resolutionVSAvoiddetection sensitivity

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent creates a multi-functional inspection system that can perform both optical inspection and electron beam inspection. The system includes multiple detectors (optical detector and electron beam detector) that can be selectively activated depending on the inspection requirements, making the system universal enough to detect various types of defects including those that SEM alone cannot detect.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent introduces an intermediary mechanism that transfers information from the sample to multiple types of detectors. The inspection system uses intermediate structures such as test structures and reference structures that mediate between the sample defects and the detection systems, enabling both optical and electron beam detectors to contribute to defect detection.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Measurement precision

If physical nanoprobing is used, then spatial resolution is improved, but inspection speed and automation deteriorate

Engineering Contradiction:

Improvespatial resolutionVSAvoidinspection speed

Core Design Contradiction:

Measurement precisionVSProductivity

Solution Approach 1:

The patent replaces the mechanical physical probing system with a beam-based detection system. Instead of using physical probes that require manual positioning and contact with the sample, the system uses electron beams and optical beams that can be rapidly directed to different locations on the sample without mechanical contact, thereby maintaining high spatial resolution while dramatically improving inspection speed and automation capability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 precise detection of previously undetectable defects, including grain dislocation and subtle voltage contrast defects, with high spatial resolution and sensitivity, improving defect localization to the individual transistor level and increasing inspection throughput.

Implementation Method 1

secondary charged particles are emitted from a surface of the specimen to be examined when electron or ion source impinges on the surface with sufficient energy

Methodology Applied

Scientific EffectElectron impact: Electron Impact Desorption

Implementation Method 2

a detector configured to produce a signal in response to detection of secondary charged particles

Methodology Applied

Scientific EffectCharged particle detection:

Data Source

PatentUS9805910B1Automated SEM nanoprobe tool

Publication Date: 2017.10.31 KLA CORP

AI summary

Aspects of the present disclosure provide an apparatus comprising a primary beam column configured to direct a primary beam of energetic particles onto a location of interest on a sample containing one or more integrated circuit structures, a detector configured to produce a signal in response to detection of secondary charged particles generated as a result of an interaction between the primary beam of energetic particles and the location of interest, and a signal processor coupled to the detector configured to measure the transient behavior of generation of the secondary charged particles from the signal produced by the detector, and a characterizing module configured to characterize the location of interest by comparing the measured transient behavior to a predetermined reference transient behavior. The detector has a response that is fast enough to detect a transient behavior of generation of the secondary charged particles.