Mechanical Stress Analysis and Evaluation of Hybrid Land Grid Array Attached Large Form Factor Organic Modules

Recent industry trends to continue enabling increased server system performance and packaging density has driven the need to implement larger form factor hybrid land grid array (LGA) attached organic modules. In addition, given the need to package multiple modules on a single printed circuit board (PCB) assembly, PCB cross-sections and their corresponding physical properties (e.g., flatness, etc.) as well as module bottom surface metallurgy (BSM) co-planarity require a more detailed understanding of impacts to the compliant as well as the soldered connector interfaces. Lastly, the migration to lead (Pb)-free solders has further complicated the issue given both the change in material properties as well as processing temperatures. In this paper we will discuss the mechanical stress analysis and evaluation tests assessment of a recently developed 50 mm square organic processor module, hybrid LGA attached to a multiple site PCB. The analysis presented will highlight the methodology to identify both connector ...