HAST test is generally called pressure cooker cooking test or saturated steam test. The most important thing is to test the test object under severe temperature, humidity (70%~100%RH) [saturated water vapor] and pressure environment. The product is resistant to high humidity, for printed circuit boards & FPC), for material moisture absorption test, high pressure cooking test, etc. For testing purposes, if the test object is a semiconductor, to test the moisture resistance of the semiconductor package, wait The test item is tested under the harsh temperature and humidity and pressure environment. If the half package is not good, the moisture will penetrate into the package along the interface of the colloid or colloid and the lead frame. Common causes of the cause: explosion effect, Corrosion caused by corrosion in the metallization area, short circuit caused by contamination between the pins of the package, etc.