Board level reliability

Life Prediction Models. The reliability test results discussed in this chapter are under accelerated conditions. For the data to be of use in gauging the reliability of actual product boards, accelerated test results need to be extrapolated to field conditions. Without acceleration factors and/or calibrated life prediction models of board level reliability under representative field conditions, product reliability claims remain unfounded. In the absence of such a bridge from test to field conditions, real products can be over-designed, at risk, or even rejected under assumptions with variable degrees of conserva-... 

Prasad, S. Carson, F. Kim, G.S. Lee, J.S. Garcia, A. Rouband, P. Henshall, G. Kamath, S. Herber, R. Bulwith, R. Board level reliability of lead-free packages. Proceedings of SMTA— International Conference, Chicago, IL, September 2000 272-276. 

The conventional design has a lot of solder joints and rehabihty is important to you. An MCM design has far fewer solder joints, resulting in less field failures and product returns. (Fhp-chip solder bumps have shown themselves to be far more reliable than the solder joints used at board level.)... 

One important consideration when designing electronics is to ensure that the electrical components operate at temperatures that will maintain long life and be reliable. Current carrying capacity of the printed circuit board traces is apart of managing the board tenperature, which directly impacts the components. (A trace is a copper conductor in a printed circuit board.The terms conductor and trace are used interchangeably for a printed circuit throughout this chapter. Track is another common term for trace or conductor.) Properly sizing the traces for current is necessary to achieve the desired temperature rise at the board level. 

JEDEC Standard, JESD22-B113, Board Level Cyclic Bend Test Method for Interconnect Reliability Characterization of Components for Handheld Electronic Products, March 2006. 

Corresponding Effects on Board Level Solder Joint Reliability, 2006 Electronic Components and Technology Conference, (2006) 891-889. 

T-C. Chiu, K. Zeng, R. Sherman, D. Edwards, and K. Ano, Effect of Thermal Aging on Board Level Drop Reliability for Pb-Free BGA Packages, 54th Electronic Components and Technology Conf. Proc., 2004, p 1256-1262... 

Experiments with third level GeoDeck boards (made in or after December 2004) could not detect any reduction in flex/shear strength at conditions given in Table 15.10. Residual load at failure was in the range of 99 + 2%, and could not be reliably measured. 

The lifetime of a population of units at the component, board, box, or system level can be divided into three distinct periods. This is most often defined by the so-called reliability bathtub curve (Fig. 6.16). The bathtub curve describes the cradle-to-grave failure rates or frequency of failures as a function of time. The curve is divided into three distinct areas early failure rate (also known as infant mortality), the useful life period, and the wearout failure period. The infant-mortality portion of the curve, also known as the early life period, is the initial steep slope from the start to... 

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