μPILRtrade package-on-package technology: development and reliability testing

Addressing the need for more memory capacity without increasing their products size, a number of companies have adapted various forms of multiple-die 3D packaging. A majority of these early multiple function devices relied on the sequential stacking of die elements onto a single substrate interposer using a conventional wire-bond process. Because the wire-bonding of multiple tiers of uncased die is rather specialized and the die used may have had relatively poor wafer level yields, overall manufacturing yield of the stacked- die packaged devices have not always met acceptable levels. The motivation for developing higher density IC packaging continues to be the consumers´ expectation that each new generation of products furnish greater functionality. The challenge electronic manufactures face when competing in the world marketplace is to offer a product that will meet all physical and performance expectations of the consumer without increasing product size or cost. The information presented in this paper focuses on recent development and the results from a stringent qualification test program for the new, very thin vertically configured (stackable) μPILR package technology designed for high performance SDRAM memory products. A key advantage of this package-on-package configuration is that each layer of the package can be electrically pre-tested before joining. This capability greatly improves the overall manufacturing yield and the functionality of the final package assembly is assured.