This standard is a critical method for evaluating the reliability of non-hermetically sealed semiconductor devices (such as automotive-grade chips, etc.) in humid environments. It employs a more rigorous approach than the traditional "85/85" steady-state temperature-humidity test by applying high pressure, high temperature, and high humidity conditions, often combined with voltage bias. This accelerates moisture penetration through protective materials or interfaces, thereby quickly exposing potential failure issues such as material degradation and corrosion. The core equipment for conducting this test is the Highly Accelerated Steady-State Temperature-Humidity Test Chamber (HAST Chamber), a specialized pressure vessel capable of precisely controlling temperature (typically above 100°C), high humidity, internal pressure, and providing electrical connection terminals. This method is primarily applicable during the product design verification phase and can significantly shorten the reliability evaluation cycle.