Overview
IEC 61189-2-803:2023 is an international standard published by the International Electrotechnical Commission (IEC). This standard defines a test method for measuring the Z-axis expansion of base materials and printed boards using a thermomechanical analyser (TMA). Z-axis expansion is a critical parameter affecting the reliability and performance of printed circuit boards (PCBs) and interconnection structures used in electronics manufacturing.
By providing a standardized procedure, IEC 61189-2-803 supports consistent quality assurance across the electronics industry. The method applies to unclad laminates, printed boards, and multilayer PCBs (without internal conductors), helping organizations evaluate thermal expansion performance and improve product reliability.
Key Topics
- Z-axis Expansion Testing: Establishes a method to measure dimensional changes perpendicular to the PCB surface under temperature variation, using a TMA.
- Test Specimen Preparation: Details on preparing, conditioning, and selecting representative samples to ensure accurate and repeatable measurements.
- Testing Procedure: Guidelines for calibration, handling, and execution of the thermal scan, typically from room temperature up to 260°C, simulating reflow soldering conditions.
- Calculation of Results: Procedures to calculate the coefficient of thermal expansion (CTE) below and above the material's glass transition temperature (Tg), and overall percentage expansion.
- Reporting Requirements: Standardized report elements, including test setup, specimen details, environmental conditions, testing parameters, and calculation outcomes.
Applications
IEC 61189-2-803:2023 serves a range of practical applications across the electronics and PCB industries, targeting both manufacturing quality and product longevity:
- PCB Fabrication: Enables manufacturers to assess Z-axis thermal expansion in base materials and assembled boards, essential for choosing materials suitable for high-reliability electronics.
- Material Selection: Assists engineers in evaluating laminate suitability for applications subjected to thermal cycling, helping to minimize issues such as delamination, via cracking, or solder joint failures.
- Quality Control: Offers a repeatable method for internal and third-party laboratories to verify compliance with specification requirements for thermal stability.
- Process Improvement: Supports R&D and process optimization by providing data on how fabrication changes or material variations affect thermal expansion characteristics.
- Customer Assurance: Ensures that delivered products meet internationally recognized testing criteria, thereby fostering confidence among OEMs and end users.
Related Standards
Organizations engaging with IEC 61189-2-803:2023 may also find the following standards highly relevant:
- IEC 60194-1: Provides terminology and vocabulary for the design, manufacture, and assembly of printed boards-a key reference within IEC 61189-2-803.
- IPC-TM-650 Method 2.4.24C: Specifies an industry-recognized test for glass transition temperature and Z-axis thermal expansion in PCBs.
- Other IEC 61189 Series: Covers additional testing methodologies for electrical materials, printed boards, and interconnection structures, supporting comprehensive quality management across the PCB lifecycle.
Summary
IEC 61189-2-803:2023 standardizes the process for evaluating Z-axis expansion in PCB materials and assemblies using a thermomechanical analyser. By following this approach, organizations can ensure product robustness against thermal stress, meet global quality criteria, and streamline the development of reliable electronic assemblies. This standard is essential for PCB manufacturers, material suppliers, testing laboratories, and quality assurance professionals focused on electronics manufacturing and interconnection reliability.