28 Jan 2024 Highly Accelerated Stress Screening (HASS)
Stands for a highly accelerated stress test in order to be able to carry out a quality test during production. An (extremely) high load is applied to the test specimens for a certain period of time in order to determine the duration until failure of the assembly. The test is also abbreviated to HASS (Highly Accelerated Stress Screening) or HAST (Highly Accelerated Stress Test). The scope of the test can include individual components and entire systems.
Colloquially, a typical HAST test setup is also referred to as a pressure cooker. Power modules are “cooked” at 130°C and 85% humidity for 96 hours and tested electrically and mechanically. The test is standardized according to EN60749. The aim of the test is to check production-related quality differences between batches and to determine production variations. The causes of failure in the test are also often compared with field returns in order to generate more knowledge about the load in the actual application.