VIA-IN-PAD PLATED OVER (VIPPO) DESIGN CONSIDERATIONS FOR ENTERPRISE SERVER AND STORAGE HARDWARE

摘要

It has been estimated that ninety percent of the world's data has been created in the last two years. Explosive demand for sensor integration, automation, analytic insights, social networking, and the emerging Internet of Things, are all fueling the need for ever increasing computing horsepower. Enterprise Class Server and Storage computing systems are expected to manage these increasing data volumes securely - enabling processing, transmission, and storage of the data at lightning fast speeds; while at the same time operating at lowest possible energy consumption rates. To achieve this, multiple hardware advancements in power delivery/regulation, microprocessors, optics, flash memory, and graphics interfaces (among others) continue to be made. Increased functionality is occurring at multiple levels; within silicon dies (cores/stacked compute-memory), multi-functional integrated components, high I/O connectors/cables, and various printed circuit board (PCB) technologies. Component placement densities of electronic packages on PCBs continues to increase. Advanced component functionality is driving more I/O signal channels and more power/ground distribution layers. Power regulators and FETs are operating at higher power levels and must deal with increased heat duties; thermal management of these devices is critical for reliable operation. From a system perspective, product form factors (rack sizes) continue to be standardized and are not getting any larger. In order to accommodate these next generation requirements, Enterprise Class printed circuit board assemblies (PCBAs) are now being designed using a variety of advanced via structures - including via in pad plated over (VIPPO) technology. Integration of VIPPO vias helps provide a solution to a variety of challenges including: increased system functionality, increased component placement densities, signal routing/fan-out constraints, and thermal/power distribution management. This paper discusses a variety of elements concerning VIPPO technology including high quality PCB manufacturing construction, VIPPO usage applications, decision making pros and cons of the technology, key PCBA design parameters of interest, and new findings regarding VIPPO interconnect reliability performance and sensitivity to PCB attributes. The intent of the paper is to discuss key considerations, design elements, and assembly reliability performance observed to date when using VIPPO structures on Enterprise Class Server and Storage hardware.