Coupled accelerated stress tests for comprehensive field reliability — Synergistic effects of moisture and temperature cycling

IC components are exposed to a variety of environmental effects in their usage environments. These include exposure to warm and humid ambient environments, sequences of power and temperature cycles as well as exposure to extreme hot and cold temperatures in the manufacturing and shipping flow as well as in the field during customer use. The mechanical integrity of polymeric materials used in packaging and the fragile extremely low-k dielectric materials in the chip are significantly influenced by moisture absorption and cold temperature exposures. Furthermore, the combined effect of moisture exposure and temperature or power cycling accelerates chip - package failures significantly. A complete assessment of the cumulative amount of moisture exposure as well as the number of temperature cycles and temperature extremes from shipping/storage and through end-customer use is required to guarantee product reliability. This paper will examine the need for combined moisture and temperature cycle stresses for process/product certifications to risk assess true field reliability. Current JEDEC standards do not incorporate combination stresses. This paper will take a first step towards proposing such a standard combination stress for product qualifications.