Issue link: https://iconnect007.uberflip.com/i/1143487
28 PCB007 MAGAZINE I JULY 2019 Feature by Dr. Paul Wang, Vincent Weng, and Dr. Kim Sang Chim MITAC INTERNATIONAL INC. Abstract Interconnect reliability—especially in BGA solder joints and compliant pins, which are subjected to design parameters—is very criti- cal to ensure product performance at pre- defined shipping conditions and user environ- ments. Plating thickness of the compliant pin and the damping mechanism of electronic sys- tem design are key success factors for this pur- pose. In addition, transportation and material handling process of a computer server system will be affected by shock under certain con- ditions. Many accessory devices in the server computer system tend to become loose, result- ing in poor contact or solder intermittent inter- connect problems due to the shock load from the transportation and material handling pro- cesses. In this article, design variables—such as pin hard gold plating thickness, motherboard lock- ing mechanism, and damping structure de- sign—are experimented and reviewed. Also, a shock measurement device is used to real- time monitor the acceleration, duration, and direction of shock in large stationary or mov- ing systems in transportation and transferring process. There were two transportation routes from Fushan, China, to Sezimovo, Czech Re- public, through the China and Russia border by train and returned by sea cargo through the Mediterranean, Arabic, and South China Seas in which a product package was embedded with a shock measurement device. The collect- ed force data of g-force can be used to calcu- late the shock energy level, ΔV. The compari- son between the value of ΔV and shock energy tested in the lab can be used to judge whether a system design can sustain and cause contact interconnect problems in the transportation and transferring process. These design vari- ables and stresses can be evaluated by drop test or vibration test to ensure system function- al integrity is achieved. Introduction Reliability of BGA solder joints and compli- ant pin interconnects is critical to ensure prod- uct performance is maintained at predefined Interconnect Reliability Correlation With System Design and Transportation Stress