Overview
IEC 62951-7:2019 is an international standard developed by the International Electrotechnical Commission (IEC) that specifies a test method for characterizing the barrier performance of thin film encapsulation used in flexible organic semiconductor devices. This part of the IEC 62951 series focuses on measuring the ultra-low water vapor transmission rate (WVTR) of thin-film barriers under both flat and bending conditions. It is especially relevant for the evaluation of flexible and stretchable semiconductor devices that rely on organic semiconductor materials.
The standard provides detailed procedures including specimen preparation, sensor film deposition, electrical contact methods, measurement setup, calculation techniques, and test conditions such as temperature, humidity, and testing duration. The primary objective is to ensure reliable and reproducible assessment of barrier layers that protect organic thin film transistors (OTFTs) and other flexible organic semiconductors from degradation caused by moisture ingress.
Key Topics
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Barrier Performance Measurement
The standard focuses on quantifying barrier layers’ capability to prevent water vapor permeation, which critically affects flexible organic semiconductor reliability.
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Ultra-Low Permeation Rates
It addresses the need for detecting WVTR at levels below conventional measurement thresholds (under 10^-4 g/m²/day), essential for protecting sensitive organic devices.
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Calcium (Ca) Conductance Sensor Method
The test employs a calcium sensor film that changes electrical resistance upon oxidation by moisture. This change is precisely measured using the four-wire resistance measurement technique, allowing detection of minute moisture permeation through the barrier.
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Test Conditions and Setup
Specific conditions such as temperature, relative humidity, and bending radius are controlled during testing to simulate real operating environments for flexible electronics.
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Specimen Preparation
Guidelines describe how to prepare sensor films and electrical contacts on substrates, ensuring consistency and accuracy in barrier performance evaluation.
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Measurement Under Bending Conditions
Recognizing that flexible devices are subject to mechanical stress, the standard includes procedures for testing barrier performance while substrates are bent, reflecting practical use cases.
Applications
IEC 62951-7:2019 is applicable for manufacturers, researchers, and quality assurance teams involved in the development and production of flexible organic semiconductor devices. Typical applications include:
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Flexible Organic Thin Film Transistors (OTFTs)
Assessing thin film encapsulation that protects OTFTs from moisture-induced performance degradation.
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Wearable Electronics
Ensuring that barrier films maintain integrity when devices flex and move during daily use.
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Flexible Displays and Sensors
Validating encapsulation materials that preserve device longevity under bending and environmental exposure.
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R&D for Encapsulation Materials
Enabling comparative analysis of innovative thin-film barriers with ultra-low water vapor permeability.
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Quality Control and Standardization
Providing a reproducible test method to certify barrier layer performance according to international standards.
Related Standards
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IEC 62951 Series
Covers flexible and stretchable semiconductor devices comprehensively, with this document as Part 7 focusing on barrier testing methods.
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ISO 15106-1
Defines water vapor transmission rate (WVTR) measurement methods applicable in packaging and related fields, serving as a normative reference for terminology.
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Other WVTR Standards
Conventional standards measuring higher permeation rates exist but are insufficient for the ultra-low permeability requirements in flexible organic semiconductors.
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ISO/IEC Directives, Part 2
Provides guidance on drafting and structuring international standards harmoniously, as referenced in the preparation of this document.
Keywords: IEC 62951-7, flexible semiconductor devices, organic semiconductor encapsulation, water vapor transmission rate, WVTR, thin film barrier, calcium sensor, four-wire resistance measurement, flexible electronics testing, bending condition measurement, flexible organic thin film transistor, OTFT barrier performance, ultra-low permeation rate testing, flexible semiconductor reliability.
Open preview (PDF)Semiconductor devices - Flexible and stretchable semiconductor devices - Part 7: Test method for characterizing the barrier performance of thin film encapsulation for flexible organic semiconductor
