Enhancing Mechanical Shock Performance Using Edgebond Technology
Authors: Steven Perng, Tae-Kyu Lee, and Cherif Guirguis; and Edward S. Ibe Company: Cisco Systems, Inc. and Zymet, Inc. Date Published: 10/13/2013
Abstract: Edgebond adhesives have been widely used by the industry for improving the shock performance of area array packages . Most of the studies focus on the impact of material properties, such as coefficient of thermal expansion (CTE) and glass transition temperature (Tg), on reliability at room temperature. However, the operating temperature of a component on the printed circuit board bonded with edgebond adhesive can be close to or exceed Tg of the adhesive, where the material properties may be very different than at room temperature. A test vehicle with a 1 mm pitch 52.5x52.5 mm2 FCBGA is designed to study the impact of testing temperature on shock performance of edgebond material. Five edgebond adhesives with different Tg and filler content are tested at both room temperature and at 100°C. A non-edgebonded FCBGA is used as the benchmark. The results indicate that shock performance is degraded as the testing temperature increases from room temperature to 100°C. However, by either increasing Tg of the adhesive or by adding filler into the edgebond adhesive, the shock performance is improved. In summary, when using edgebond adhesive as an enhancement tool for shock performance, users may need to consider operating temperature during the material selection process. Material been selected, should have a Tg that is in the close vicinity of or higher than the operating temperature to provide needed or expected shock protection.
Edgebond, FCBGA, mechanical shock, elevated temperature shock test