Reliability practices for satellite design and assembly focusing on FMECA, cleanliness and X-ray inspection

摘要

Because most space systems are extremely complex, and need to service long enough under extreme environmental conditions, it is necessary to perform, execute, and provide a method of risk identification during the design stage. The Failure Modes Effects and Criticality Analysis, FMECA has been recognized as such an effective approach that provides the necessary visibility during the design period by identifying mission critical failure modes and provides an input for design alteration. Besides design improvement tools, the manufacturing and inspection procedures of space application products like satellite need to take care special attention. The cleanliness requirements of soldering and assembly areas should be supplied to avoid the occurrence of failure mechanisms caused by contaminants like particulates; such as dirt, sand, industrial fumes, hair cosmetics, dead human skin cells, fibers and lint from clothing, chips and burrs from machined surfaces and etc. As a sophisticated inspection tool, X-ray is particularly beneficial for the evaluation of solder joints and assemblies that involve advanced packaging technologies such as: Ball grid array (BGA), land grid array (LGA), chip size package (CSP), flip chip (FC), wafer level packaging (WLP), system in package (SIP) and quad flat-pack no leads (QFN) etc. The use of X-ray inspection is forced by the standards for space application products BGA solder joints. The defects can be detected by X-ray inspection are; shorts, voiding, delamination, missing part, open, misalignment, warpage, counterfeit components etc.