Board level reliability for laminate CSP

An experiment was conducted to determine card assembly reliability of 0.8 mm laminate chip scale packages (CSPs) on FR4 card material. Accelerated temperature cycle tests (TCT) and card-bending tests were conducted to determine the optimum size and type of pad for card assemblies. Toshiba supplied the CSPs for this study. The CSPs were 177 I/O 13 mm/spl times/13 mm overmolded packages with laminate interposers. XeTel supplied the cards and card assembly. Toshiba performed the accelerated testing. Two nonsolder-mask defined (NSMD) pad designs and two solder-mask defined (SMD) pad designs were used for the test card. The temperature cycle range was from -55/spl deg/C to +125/spl deg/ C. CSP reliability was determined in an independent study by Toshiba, the results of which are included for reference. CSP construction and reliability, card design and assembly processes, test results, and conclusions are presented.