Foreword

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This document was prepared by Technical Committee ISO/TC 61, Plastics, Subcommittee SC 12, Thermosetting materials.

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Introduction

With the advancement of large-scale integration of integrated circuits and miniaturization of electronic components, thermosetting resin-based materials have been increasingly adopted in power electronics device encapsulation. However, their low-temperature brittleness can lead to encapsulation cracking failures.

This document introduces the embedded metal block method, and the corresponding moulds, stress module and sample preparation are also recommended. The method simulates encapsulation structures by pre-embedding stress modules in test specimens and determines the critical temperature for material cracking through thermal testing. A quantitative evaluation methodology, the low-temperature cracking index (CR), is established accordingly. This method has been applied by power electronics manufacturers for screening and validation of encapsulation materials such as epoxy resins.

This document facilitates innovation in material research and development and enhances the reliability of electronic devices.

1 Scope

This document defines a method for testing the low-temperature cracking index of thermosetting resin-based materials.

The test method described in this document is suitable for quantifying and comparing the low-temperature cracking of thermosetting resin-based materials in laboratory settings.

This document does not refer to thermosetting resin-based materials that can also crack at 0 °C and above.

2 Normative references

3 Terms and definitions

4 Apparatus

4.1

4.2

4.3

4.4

5 Test method

5.1 mould and stress module

5.2 Specimen preparation

5.3 Test procedures

6 Low-temperature cracking index calculation

7 Test report

Bibliography