IEC 60749-35:2006

Overview

IEC 60749-35:2006 is an international standard developed by the International Electrotechnical Commission (IEC), focusing on the procedures for performing acoustic microscopy on plastic encapsulated electronic components. This standard is part of the IEC 60749 series, which specifies mechanical and climatic test methods for semiconductor devices.

IEC 60749-35:2006 provides comprehensive guidance on using acoustic microscopy as a non-destructive, reproducible technique to detect potential anomalies-such as delamination, cracks, and voids in the mould compound-within plastic packages of semiconductor devices. By standardizing test procedures, this document helps ensure the reliability and quality of plastic-encapsulated electronic components in the supply chain.

Key Topics

• Acoustic Microscopy Methods: The standard details both reflective and through transmission acoustic microscopy systems. It outlines the necessary equipment, including pulser/receivers, transducers, fluid bath mediums, and computer-controlled scanning and imaging systems.

• Detection of Anomalies: Procedures focus on reliably detecting issues such as:

  • Delamination between materials
  • Internal cracks
  • Voids in mould compounds

• Non-Destructive Evaluation (NDE): The test methods aim to preserve the integrity of the component while offering valuable insights into its structural state.

• Scanning Modes and Data Representation:

  • A-mode: Used mainly for equipment focus, capturing amplitude and phase/polarity at a specific point.
  • B-mode: Provides cross-sectional (X-Z or Y-Z) images to reveal defects by depth.
  • C-mode: Provides two-dimensional top-view images at a particular depth, widely used for compliance checking.
  • Through Transmission Mode: Used for initial quick scans to identify large defects.

• Defined View Areas: The standard refers to specific interface areas, such as die attach, leadframe, die surface, substrate interfaces, and underfill regions, to localize potential failure points.

Applications

IEC 60749-35:2006 is essential for organizations engaged in the design, manufacturing, qualification, and failure analysis of plastic encapsulated semiconductor devices. Practical application areas include:

• Quality Assurance: Ensures consistent detection of manufacturing anomalies before products reach the market.
• Failure Analysis: Aids engineers in pinpointing root causes by characterizing internal defects non-destructively.
• Process Optimization: Enables the assessment of material compatibility and encapsulation processes, supporting improvements to assembly lines.
• Supplier Evaluation: Standardized test results facilitate fair supplier comparisons and compliance verification.
• Reliability Testing: Supports long-term reliability predictions by revealing delamination and other degradation mechanisms early in the product lifecycle.

Related Standards

IEC 60749-35 is part of a comprehensive family of standards for semiconductor device environmental and mechanical testing, including:

• IEC 60749-20: Resistance of plastic-encapsulated surface-mounted devices to combined humidity and soldering heat
• IEC 60749-6: Storage at high temperature
• IEC 60749-24: Accelerated moisture resistance - Unbiased HAST (Highly Accelerated Stress Test)
• IEC 60749-10: Mechanical shock tests for semiconductor devices
• IEC 60749-33: Accelerated moisture resistance - Unbiased autoclave
• IEC 60749-30: Preconditioning of non-hermetic surface mount devices prior to reliability testing

Referencing adjacent standards ensures broader compliance and reinforces the robustness of the entire component evaluation process.

Summary

By defining standardized procedures for acoustic microscopy, IEC 60749-35:2006 supports manufacturers, testing laboratories, and quality engineers in reliably and non-destructively evaluating plastic encapsulated electronic components. Adoption of this standard leads to improved detection of hidden defects, helping reduce field failures, improve overall product quality, and maintain industry confidence in semiconductor device reliability.