Definition and Test Standards
The highly accelerated temperature and humidity stress test (HAST) is a highly accelerated method of electronic component reliability testing using temperature and humidity as the environmental parameters. HAST is also known as the pressure cooker test (PCT) or unsaturated pressure cooker test (USPCT). Its purpose is to evaluate a specimen’s humidity resistance by increasing the water vapor pressure in a test chamber to an extremely high level above the partial water vapor pressure inside the test sample. This process temporally accelerates the infiltration of moisture into the sample.
Test standards
HAST is a more accelerated version of accelerated humidity resistance testing. Compared to high-temperature & high humidity testing (at 85°C & 85% RH, sometimes called as “double-85 test”), HAST causes more component contact due to moisture driven corrosion and more insulation deterioration. HAST is done mainly on plastic sealed components.
IEC60068-2-66, IEC60749-4, JESD22-A102, JESD22-A110, JESD22-A118 and JICS60068-2-66 are the major HAST-related test standards that are widely applied in the world. The test is performed at a specified temperature and relative humidity or pressure.The atmosphere normally has a temperature of at least 100°C, in a state of water vapor pressurization. HAST is sometimes classified as a combined test when pressure is also considered as an environmental parameter. There are saturated and unsaturated varieties of HAST. The former is typically done at conditions of 121°C and 100% RH and the latter at conditions of 110,120 or 130°C and 85% RH. Tests done with the electronic component’s power on are usually the unsaturated type. HAST is a fairly extreme test which makes it important to check failure modes.
HAST chamber by GAAT
Through our continuous research and innovation, we have made breakthrough and developed our new generation HAST chamber with double-container system design, in which the test chamber and the steam generator chamber are independent from each other. Compared to a single-container structural design, our machine can provide a more stable and accurate testing environment, allow wider humidity range and prevent the dewing problem.
Our standard HAST chamber model comes with inner volume φ420*500mm (Diameter*Depth), with minimal 20 bias terminals pre-set on the chamber door side (up to 300 bias terminals as option), allows testing for larger size specimen and convenient operation of specimen power connection. In parallel, we offer wider range of temperature and humidity settings for our customers to fulfill their various testing requirements.
Temperature range: 105℃～150℃
Humidity range: 65%～100%RH
The range chart of temperature, humidity and pressure below:
(note: the pressure value shown on the chart is absolute pressure)
GAAT’s HAST chamber is also calibrated and certified by CEPREI, China’s most authoritative lab for calibration and certification in electronics and semiconductor sector. CEPREI tested multiple points (including 105℃ 100%RH；110℃ 85%RH；120℃ 85%RH；121℃ 100%RH；130℃ 85%RH；140℃）and all got satisfactory results. We offer such a high quality instrument with competitive price and short lead time. Please don’t hesitate to contact our sales team for full chamber specification sheet, quote and calibration report.
