Escape routing in modern area array packaging: An analysis of need, trend, and capability

With the increasing complexity in the die and package designs and ever increasing cost pressure in today's microelectronic industry, the design for input/output (I/O) routing has assumed a vital role in the overall product design. This scenario is primarily driven by the increase in the I/O terminal counts in both die and package. Several authors have already described the possibility of using various escape routing models in order to maximize the number of I/Os in a given area. However, these models suffer from many drawbacks and fail to address the importance of processing factors and the actual manufacturing conditions. Therefore, a new design guideline for escape routing has been developed to achieve the maximum I/O density under the actual manufacturing, processing and cost related constraints. The correlation between the real world constraints and their impact on I/O routing has been explored and used as a foundation for developing design guidelines. This approach has been presented through a comprehensive case study that covers various design scenarios, provides the right set of real world trade-offs that need to be considered and simultaneously highlights the drawbacks in existing models.