Laminate MEMS for Heterogeneous Integrated Systems

Abstract

Post semiconductor manufacturing processes (PSM), including packaging and printed circuit board (PCB) manufacturing are now capable of producing trace widths of a few micrometers, high aspect ratio vias, three-dimensional constructions, and highly integrated systems in a single small package. Such PSM technology can in principle be used to manufacture micro electromechanical systems (MEMS) for sensing and actuation applications. Although MEMS are traditionally produced using silicon processes, the broad array of manufacturing approaches available in the packaging industry, including lamination, lithography, etching, electroforming, machining, bonding, etc., and the large number of available materials such as polymers, ceramics, metals, etc., provides greater design freedom for producing functional microdevices. The results of such processes applied to fabricating small systems are heterogeneously integrated MEMS devices. Since lamination of stacked layers is a critical component of this process, we refer to these devices as "laminate MEMS."In many cases laminate MEMS devices are more suited to their applications than their silicon counterparts, especially for applications such as biomedical, optical, and human computer interface. Furthermore, such microdevices can be built with a high degree of integration, prepackaged, and at low cost. Indeed, the PCB and packaging industries stand to benefit greatly by expanding their offerings beyond serving the semiconductor industry and developing their own devices and products. This paper illustrates that good quality MEMS devices can be manufactured using packaging style fabrication, particularly using stacks of laminates, and discusses some of the unique benefits of such devices. This laminate MEMS technology promises not only improved methods for manufacturing microdevices but also for heterogeneously integrating them with silicon microelectronics and other components into a single package.