IBM Corporation

Characterization, Prevention and Removal of Particulate Matter on Printed Circuit Boards

Dec 22, 2016 | Prabjit Singh, Patrick Ruch, Sarmenio Saliba - IBM Corporation, Christopher Muller - Purafil Inc.

Particulate matter contamination is known to become wet and therefore ionically conductive and corrosive if the humidity in the environment rises above the deliquescence relative humidity (DRH) of the particulate matter. In wet condition, particulate matter can electrically bridge closely spaced features on printed circuit boards (PCBs), leading to their electrical failure. (...)

The objective of this paper is to develop and describe a practical, routine means of measuring the DRH of minute quantities of particulate matter (1 mg or less) found on PCBs....

Corrosion Resistant Servers for Free-Air Cooling Data Centers

Nov 10, 2016 | Qiujiang Liu; Baidu, Inc., Prabjit Singh; IBM

The demand for compute capability is growing rapidly fueling the ever rising consumption of power by data centers the worldwide. This growth in power consumption presents a challenge to data center total cost of ownership. Free-air cooling is one of the industrial trends in reducing power consumption, the power usage effectiveness (PUE) ratio, and the total cost of ownership (TCO). Free-air cooling is a viable approach in many parts of the world where the air is reasonably clean. In Eastern China, the poor quality of air, high in particle and gaseous contamination, is a major obstacle to free-air cooling. Servers exposed to outside air blowing in to data centers will corrode and fail at high rate. The poor reliability of hardware increase TCO dramatically.

This paper describes a corrosion resistant server design suitable for reliable operation in a free-air cooling data center located in Eastern China where the indoor air quality can be as poor as ASHRAE (American Society of Heating, Refrigerating and Air-Conditioning Engineers) severity level G3. An accelerated corrosion test method of verifying hardware reliability in the ASHRAE severity level G3 environment is also described....

Inclusion Voiding in Gull Wing Solder Joints

Aug 30, 2012 | T.L. Lewis, C.O. Ndiaye, J.R. Wilcox

This paper provides definitions of the different voiding types encountered in Gull Wing solder joint geometries. It further provides corresponding reliability data that support some level of inclusion voiding in these solder joints and identifies the final criteria being applied for certain IBM Server applications. Such acceptance criteria can be applied using various available x-ray inspection techniques on a production or sample basis. The bulk of supporting data to date has been gathered through RoHS server exempt SnPb eutectic soldering operations but it is expected to provide a reasonable baseline for pending Pb-free solder applications....

Improvement of Organic Packaging Thermal Cycle Performance Measurement

Nov 01, 2006 | Glenn O. Dearing, Paul J. Hart

Flip Chip Plastic Ball Grid Array (FCPBGA) modules, when subjected to extreme environmental stress testing, may often reveal mechanical and electrical failure mechanisms which may not project to the field application environment. One such test can be the Deep Thermal Cycle (DTC) environmental stress which cycles from -55°C to 125°C. This “hammer” test provides the customer with a level of security for robustness, but does not typically represent conditions which a module is likely to experience during normal handling and operation....