Semiconductor Crack Detection via Embedded Electrode Leakage Current

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Solution Overview

Problem

Existing methods for detecting cracks in semiconductor wafers during the dicing process lack precision, particularly for minute cracks that do not significantly affect electrical characteristics, leading to potential failures in subsequent assembly and usage due to assembly stress or environmental factors.

Innovation Solution

A semiconductor device with a crack detection structure in the edge termination region, featuring a trench with an inner-wall insulating film and an embedded electrode, connected to a monitor electrode, which measures leakage current or potential difference to detect cracking progress with high precision.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a diffusion layer or electrode is used as a crack detection line with large resistance change requirement, then the manufacturing process is simple, but the measurement precision is insufficient for minute cracks

Engineering Contradiction:

Improvecrack detection precisionVSAvoiddetection structure complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The crack detection function is segmented into multiple components: a trench structure for physical crack interception, an insulating film for electrical isolation, and an embedded electrode for signal detection. This segmentation allows each component to specialize in one aspect of crack detection, achieving high precision without requiring excessive complexity in any single component.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The insulating film serves as an intermediary between the trench and the embedded electrode, enabling the electrode to detect electrical field changes caused by cracks while being physically protected. This intermediary structure allows precise detection of minute cracks through electrical field monitoring without direct exposure of the sensing element to mechanical damage.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If wafer thickness is reduced to save energy and downsize devices, then electrical characteristics are enhanced, but handling difficulty and crack susceptibility increase

Engineering Contradiction:

Improveelectrical characteristicsVSAvoidcrack susceptibility

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The crack detection structure is built into the wafer before dicing and subsequent processing steps. By having the detection infrastructure in place beforehand, cracks can be detected as soon as they occur during dicing or later during assembly and usage, allowing preventive actions to be taken before failures occur.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent replaces mechanical crack detection methods (visual inspection, physical testing) with electrical field-based detection. The embedded electrode monitors changes in electrical fields caused by cracks, enabling non-contact, non-destructive detection that does not add mechanical stress to the already-thin wafer structure.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Productivity

If visual inspection or electrical characteristic testing is used to reject cracked chips, then large cracks can be identified, but minute cracks remain undetected

Engineering Contradiction:

Improveinspection efficiencyVSAvoidcrack size detection capability

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The detection method changes the monitoring parameter from visual appearance or bulk electrical characteristics to localized electrical field distribution around the embedded electrode. This parameter change enables detection of minute cracks that do not affect overall electrical characteristics or visual appearance, as even small cracks alter the local electrical field in detectable ways.

Inventive Principle:

Principle #35Parameter changes

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 monitoring of cracking progress by significantly changing leakage current or potential difference when a crack reaches the detection structure, preventing undetected minute cracks from progressing to failure.

Implementation Method 1

monitor the cracking progress by measuring the leakage current or the potential difference between the monitor electrode and another electrode

Methodology Applied

Scientific EffectElectrical conduction and potential difference measurement: Conduction (electrical)

Data Source

PatentUS11531053B2Semiconductor device and crack detection method

Publication Date: 2022.12.20 MITSUBISHI ELECTRIC CORP

AI summary

Provided is a semiconductor device that can detect the cracking progress with high precision. A semiconductor device is formed using a semiconductor substrate, and includes an active region in which a semiconductor element is formed, and an edge termination region outside the active region. A crack detection structure is termed in the edge termination region of the semiconductor substrate. The crack detection structure includes: a trench formed in the semiconductor substrate and extending in a circumferential direction of the edge termination region; an inner-wall insulating film formed on an inner wall of the trench; an embedded electrode formed on the inner-wall insulating film and embedded into the trench; and a monitor electrode formed on the semiconductor substrate and connected to the embedded electrode.