Reliability of MEMS: A perspective on failure mechanisms, improvement solutions and best practices at development level

• Formal definition of reliability of MEMS.
• Identification of the main failure mechanisms and of physics of failure.
• Review of a few solutions published in literature to improve reliability of various MEMS devices.
• Brief discussion of best practices to be followed in the design of high-reliability MEMS.

Reliability of MEMS (MicroElectroMechanical-Systems) devices is a crucial aspect as it can discriminate the successful from partially or totally missed reaching of Microsystem technology based market products. However, the topic of MEMS reliability is significantly articulated, as it comprises numerous physics of failure and diverse failure mechanisms. Thereafter, it requires a pronounced sensitivity related to the actual operation conditions (environmental and functional) of the Microsystem device within the final application. In other words, reliability of MEMS is nowadays regarded as a standalone transversal discipline that must be seriously taken into account already from the early design phase. The purpose of this paper is to provide the reader at first with basic knowledge around the concept of reliability. Thereafter, the most relevant physics of failure and failure mechanisms typical of MEMS are grouped and briefly discussed, with specific attention to their employment in the field of displays. A synthetic review of valuable solutions to improve specific reliability aspects of MEMS devices for diverse applications is then proposed to the reader. Eventually, a brief discussion focused on best practices to address properly reliability during the whole development chain of innovative MEMS based products completes the contribution. It is a belief of the author that the particular blend of topics and aspects reported in the following pages, as well as the attitude of considering reliability as a transversal discipline of science, contribute to provide this contribution with an important benefit if compared to the reviews on reliability of MEMS previously published in literature.