A LOW COST RELIABILITY ASSESSMENT FOR DOUBLE-SIDED MIRROR-IMAGED FLIP CHIP BGA ASSEMBLIES

摘要

In recent years, much development in the fast growing electronics industry has been focused on high density interconnect (HDI) packages. To take full advantage of both the Flip Chip and BGA technologies, most major IC suppliers have introduced high I/O (>1500) Flip Chip Ball Grid Array (FCBGA) type packages. This package has assumed an important role in double-sided mirror-imaged assemblies for high-speed networking applications. However, the enormous size of the component creates a challenge for contract manufacturing companies, particularly when they populate on both sides of the board. To achieve and maintain the same quality and reliability as other assemblies is also a real challenge. To study the reliability of double-sided mirror-imaged assemblies for high I/O FCBGA packages, the reliability results from tests on a low-cost, fast-turn Mechanical Deflection System (MDS) are compared to those traditional reliability tests such as Accelerated Thermal Cycling (ATC), Shock, and Vibration tests. The failure modes of solder joint after the destructive thermal and mechanical stress tests are investigated by using cross-sections, Scanning Electron Microscopy (SEM), Energy Disperse X-Ray Spectroscopy (EDX), and Dye Penetration techniques. Once the correlation between MDS and the traditional reliability test results has been established, the low cost MDS test can be used as a standard reliability assessment technique to verify the manufacturing process and reliability projections. This research has established a valuable database to correlate the low cost MDS test and traditional reliability tests enabling the use of a low cost fast-turn solution for reliability and manufacturability assessments in a production environment.