HAST

1. Project introduction

Highly accelerated temperature and humidity stress testing (HAST) is a highly accelerated, temperature- and humidity-based test method for electronic component reliability. HAST is also known as stress test (PCT) or unsaturated pressure test (USPCT). The aim is to evaluate the test sample by increasing the water vapor pressure in the test chamber to a certain moisture resistance. Much higher than partial water vapor pressure inside the specimen. This process temporarily accelerates the penetration of water into the sample. Sembcorp Nano conducts UBHAST (Unbiased High Speed Life Test) and BHASHT (High Accelerated Temperature and Humidity and Bias Test).

Experimental Objective: To evaluate the resistance of IC products to humidity under bias, high temperature, high humidity and high atmospheric pressure conditions, and accelerate its failure process.

Test conditions: 130°C, 85%RH, 1.1VCC, Static bias, 230Kpa 96H

110℃，85%RH，1.1VCC，Static bias，122Kpa 264H

Failure mechanism: delamination, ionization corrosion, electrical properties on/short circuit, package tightness

Reason for failure:

(1) Because the pads are corroded, the line is open

(2) Short circuit or leakage due to moisture absorption or ion migration

(3) The resistance of the PN junction increases, resulting in current drift

Improvement measures:

(1) Improve the adhesion between EMC and PCB

(2) EMC with low moisture absorption and high adhesion are selected

Reference standard: JESD22-A110/A118)