Challenges in the packaging of MEMS

Unlike IC packaging, MEMS dice must interface with the environment for sensing, interconnection, and/or actuation. MEMS packaging is application specific and the package provides the physical interface of the MEMS device to the environment. In the case of a fluid mass flow control sensor, the medium flows into and out of the package. This type of packaging is referred to as media compatible packaging. Harsh environments may create different challenges for the packaging of MEMS. In addition to challenges related to the MEMS chip environment and interfacing with that environment, challenges also exist inside the MEMS package, such as die handling, die attach, interfacial stress, and outgassing. These new challenges in MEMS packaging need immediate research and development efforts. To date, most of what is known about MEMS packaging remain proprietary secrets and published literature is scarce. The challenges of MEMS packaging have been known for some time, but little open research has been done to collect data and work toward meeting these challenges. A disproportionality exists between money spent on MEMS packaging and time spent researching MEMS packaging. Currently, the cost of MEMS packaging typically accounts for 75% or more of the device sale price. MEMS packaging is already far behind the capabilities of MEMS designers, and it is the purpose of this paper to share the challenges of MEMS packaging and create an awareness and an interest in MEMS packaging within the packaging community.