By Dr. Toni T. Mattila and Dr. Mervi Paulasto-Kröckel, Professor, Aalto University
MEMS Industry Group (MIG) is pleased to bring you this blog on the Finnish National MEMS Technology Roadmap. Let this be an example of how a group of self-selected, diverse group of manufacturers/researchers in Finland came together to lay out their goals and focus for R&D in Finland. The results are impressive, and MIG members are able to download the executive summary of the report in our MIG Resource Library. I encourage you to read this blog, download the executive summary and share your thoughts on the future of R&D in MEMS to fuel commercialization. We’ll be discussing this topic, and others throughout the year as well as at our annual members’ technical conference, M2M Forum; May 8-9, 2012 in Pittsburgh. Enjoy! Karen Lightman, MIG Managing Director
Aalto University and VTT have developed, in close co-operation with representatives from the Finnish MEMS industry, a national MEMS technology roadmap. The primary objective of this roadmap is to define focus areas of research and development activities in various institutes and commercial organizations. We hope that this work will contribute in the efforts of maintaining the competitiveness and knowhow of the emerging Finnish MEMS cluster at the highest level. The roadmap will be updated at regular time intervals. This work is also expected to strengthen the co-operation between the organizations in the national MEMS cluster and to generate new long-term growth opportunities for the cluster. As a starting point in the autumn of 2010, Aalto University and VTT, in collaboration with Culminatum, carried out a questionnaire survey, which examined the view and opinions of people closely involved with the field in both commercial and academic setting. The final form of the roadmap was formulated in five workshops that were held during the spring of 2011.
The survey revealed four primary R&D activity areas: a) new applications, b) new materials, c) processing techniques, and d) packaging and integration.
The number of MEMS based applications of the future is seen quite large, but today most of them are sensor systems. For example, MEMS applications based on actuation received considerably less attention in the responses. In addition, it was striking that activities related to biomedical MEMS applications are still very small scale. Only 18 % of survey respondents indicated that their work involves bio-MEMS related applications.
As to the new materials, many of the respondents saw the allotropes of carbon, such as carbon nanotubes and graphene, as very promising new materials for fabrication of MEMS devices. Although several applications of carbon nanotubes have already been developed and demonstrated in laboratory scale, the utilization of nanotubes or grapheme, in particular, are seen to take place only in the long run (i.e. after 2020). Instead, piezoelectric materials are already used in some commercial MEMS applications and their use is expected to grow significantly in the near future. Thermal and magnetic shape memory alloys were seen as a potential alternative for MEMS actuation where displacements produced by piezoelectric materials are not large enough. Introduction of new materials is expected to decrease the use of, for example, glass and ceramics in MEMS applications in the future.
Advances in processing techniques were envisioned to be primarily related to the development of individual process steps. For example, methods to process thin-films of graphene or shape memory alloys will be an area where many efforts are needed in the near future. Breakthroughs in this area will to a large extent determine how widely these materials will be used in MEMS devices. Processes to combine conventional CMOS and MEMS fabrication processes (so-called “post processing CMOS MEMS”), bonding of dissimilar metals, Atomic Layer Deposition (ALD), structurally modified silicon (e.g. porous Si), and various methods of direct printing received a lot of attention.
Wafer Level Packaging (WLP) was seen as the primary solution for packaging and integration of MEMS based systems by vast majority of the respondents. Perhaps the most important factor for the respondents’ strong belief in the potential of MEMS packaging solutions is the fact that this technology has already shown its cost efficiency in packaging and integration of integrated circuits. In addition, the small form factor enabled by this technology can be regarded as a benefit for many applications. The current challenges related to the WLP technology are related to the three-dimensional integration and associated challenges in electrical interconnecting, such as fabrication of through silicon or through encapsulation vias and replacement of wire bonds with solution that would require less space and would be less sensitive to electrical disturbances.
Based on the questioner survey and the expert meetings the roadmap working group came to propose the following three focus areas for the near future national research and development: A) Next Generation 3D Integration of MEMS based Systems, B), Functional Materials in MEMS based Systems, and C) MEMS based Biomedical sensor/actuator systems.