Thermal Expansivity and Thermal Stress in Multilayered Structures

摘要: Thermal stress is one of the most serious reliability problems for microelectronic circuits. This aggravated because structures are mechanically complex, involving many different materials, each with its own set elastic coefficients, expansivities, and limitations. Many these effects require long service times or temperature cycles to cause failures even measurable changes, so testing new designs an extremely time-consuming costly affair. designers resorting numerical analysis, such as finite element studies, have helped greatly. There good reasons, however, perform analytical calculations well, both verify studies provide designer a feeling how various controllable parameters will affect product. Also, there some situations where analysis not available, requires unavailable expertise, may be too expensive practical. In cases, sometimes quick simplified structure immediate advice, perhaps avoid, at least minimize, thermal problems.