Overview
IEC 62137-1-4:2009 is an international standard published by the International Electrotechnical Commission (IEC) focused on surface mounting technology. Specifically, this standard describes an environmental and endurance test method for surface mount solder joints known as the cyclic bending test. It applies to surface mount components with thin and wide basal planes, such as Quad Flat Packages (QFP) and Ball Grid Arrays (BGA).
The cyclic bending test evaluates the mechanical endurance of solder joints between component leads and lands on a substrate by subjecting the substrate to repeated bending stress. This simulates real-world mechanical stress events, such as key pushing on cell phones, providing important insights into solder joint durability and long-term reliability.
Key Topics
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Scope and Applicability
Applicable to surface mount components with wide basal planes (e.g., QFP, BGA). The test evaluates solder joint strength through cyclic bending, focusing on mechanical endurance under repeated stress conditions.
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Test Methodology
- Components are mounted onto substrates using reflow soldering.
- The substrate is cyclically bent until solder joint fracture occurs or endurance limits are reached.
- The test measures the number of bending cycles a solder joint withstands, which reflects its cyclic bending strength.
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Test Equipment and Materials
- Tension-compression testing machines with substrate bending jigs.
- Test substrates made from epoxy woven glass fabric laminated sheets with specified copper foil thickness.
- Solder alloy is typically Sn-Ag-Cu (SnAg3.0Cu0.5) in accordance with IEC 61190-1-3.
- Solder paste complies with IEC 61190-1-2.
- Reflow soldering equipment must follow predefined temperature profiles to ensure quality solder joints.
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Test Procedure Details
- Solder paste is applied on defined substrate lands using stainless steel masks.
- Surface mount components are placed and reflow soldered.
- After mounting, substrates are cyclically bent using specialized equipment.
- Electrical resistance measurements or visual inspections determine solder joint integrity post-test.
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Evaluation and Reporting
Judges strength via the number of cycles to failure.
Test reports should include detailed information such as test conditions, mounting methods, solder materials, and fracture observations.
Applications
IEC 62137-1-4 is crucial for industries employing surface mount technologies, particularly where mechanical reliability of solder joints is essential:
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Consumer Electronics
Tested components like BGAs and QFPs used in smartphones, tablets, and portable devices where mechanical stress (e.g., repeated button presses) is common.
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Automotive Electronics
Ensuring solder joint endurance in vehicle control modules subject to vibrations and stress.
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Industrial Equipment
Electronic assemblies in harsh environments that require long-lasting, mechanically robust solder joints.
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Quality Assurance and R&D
Used by manufacturers and designers to assess and improve solder joint materials, substrate designs, and assembly processes.
Related Standards
IEC 62137-1-4 complements a series of international standards dedicated to surface mounting technology and solder joint testing:
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IEC 62137 Series
Covers various environmental and endurance test methods for solder joints beyond cyclic bending.
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IEC 61190-1-3
Specifies requirements for electronic grade solder alloys including Sn-Ag-Cu compositions.
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IEC 61190-1-2
Details solder paste requirements for high-quality electronic assembly.
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IEC 61249-2-7
Defines specifications for materials used in printed circuit board (PCB) substrates.
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IEC 60068-1
Provides general guidance on environmental testing applicable across electronic components.
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IEC 61188-5
Addresses land (pad) design considerations for surface mount components.
Keywords: IEC 62137-1-4, cyclic bending test, surface mount solder joint, solder joint endurance, QFP, BGA, mechanical stress testing, reflow soldering, SnAgCu solder alloy, PCB substrate testing, electronic assembly standards, surface mounting technology, solder joint reliability.