Technology for flipchip assembly on moulded interconnect devices (MID)

The technology of moulded interconnect devices (MID) offers a very interesting alternative for many applications in MEMS and MOEMS, because of its high potential in reducing the number of components and process steps and in miniaturization. In order to tap the full potential, the assembly of bare dies, especially flipchips on MID (chip-on-MID) is the way to go. In this paper a study of flipchip assembly using adhesive technology on electroless plated polymer substrates will be presented. Various kinds of adhesives and different substrates, including a special new type with moulded polymer bumps have been used. The transition resistance of the flipchip contacts has been used as an indicator for process quality and reliability after temperature shock and humidity storage testing. The thermal coefficient of expansion was found to have a major influence on the reliability. Further experiments were made e.g. to validate the proper functionality over a broad temperature range. Suitable processes for applications with various requirements could be found.