Smart MEMS Packaging: SMM for Increased Device Material Reliability

摘要

In recent years shape memory effect has drawn great interest for developing smart materials and structures that can response to the environmental conditions, and it was found that a large amount of polymer materials exhibit shape memory properties under certain thermomechanical conditions, which can be used for recovery of micro and macro damages of a structure, thus it provides a great opportunity to enhance the reliability of MEMS packaging, but up to date the shape memory effect of polymers has not been well characterized and fully understood. This paper provides a detailed experimental study on the strain recovery characteristics of a shape memory polymer. The effects of thermomechanical paths on the strain recovery, including the effects of sequence of heating and straining, the heating temperature, the strain, strain rate and load of pre-staining, the number of thermomechanical cycling and their combination, have been investigated extensively. The material behavior is analyzed with the use of a transient viscoelastic-plastic model. Possible mechanisms on the strain recovery and shape memory effect are discussed. This study is supported under the contract of W56HZV-05-C-0101 (Phase I, completed) and W56HZV-05-C-0650 (Phase II, start in Feb. 2006)