Advances in the development of novel materials and fabrication processes are resulting in an increased number of flexible and stretchable electronics applications. This evolving technology enables new devices that are not readily fabricated using traditional silicon processes, and has the potential to transform many industries, including personalized healthcare, consumer electronics, and communication. Fabrication of stretchable devices is typically achieved through the use of stretchable polymer-based conductors, or more rigid conductors, such as metals, with patterned geometries that can accommodate stretching. Although the application space for stretchable electronics is extensive, the practicality of these devices can be severely limited by power consumption and cost. Moreover, strict process flows can impede innovation that would otherwise enable new applications. In an effort to overcome these impediments, we present two modified approaches and applications based on a newly developed process for stretchable and flexible electronics fabrication. This includes the development of a metallization pattern stamping process allowing for 1) stretchable interconnects to be directly integrated with stretchable/wearable fabrics, and 2) a process variation enabling aligned multi-layer devices with integrated ferromagnetic nanocomposite polymer components enabling a fully-flexible electromagnetic microactuator for large-magnitude magnetic field generation. The wearable interconnects are measured, showing high conductivity, and can accommodate over 20% strain before experiencing conductive failure. The electromagnetic actuators have been fabricated and initial measurements show well-aligned, highly conductive, isolated metal layers. These two applications demonstrate the versatility of the newly developed process and suggest potential for its furthered use in stretchable electronics and MEMS applications.
We present a new low cost microfabrication technology that utilizes a sacrificial conductive paint transfer method to
realize thick film copper microstructures that are embedded in polydimethylsiloxane (PDMS). This process has reduced
fabrication complexity and cost compared to existing metal-on-PDMS techniques, which enables large scale rapid
prototyping of designs using minimal laboratory equipment. This technology differs from others in its use of a
conductive copper paint seed layer and a unique transfer process that results in copper microstuctures embedded in
PDMS. By embedding microstructures flush with PDMS surface, rather than fabricating the microstructures on the
substrate surface, we produce a metallization layer that adheres to PDMS without the need for surface modifications.
The fabrication process begins with the deposition of the seed layer onto a flexible substrate via airbrushing. A dry film
photoresist layer is laminated on top and patterned using standard techniques. Electroplated copper is grown on the seed
layer through the photoresist mask and transferred to PDMS through a unique baking procedure. This baking transfer
process releases the electroplated copper from the seed layer, permanently embedding it into the cured PDMS without
cracking or otherwise deforming it. We have performed initial characterizations of the copper microstructures in terms of
feature size, film thickness, surface roughness, resistivity, and reliability under flexing. Initial results show that we can
achieve films 25-75 micrometers in thickness, with reliable feature sizes down to 100 micrometers and a film resistivity
of approximately 7.15 micro-Ω-cm. Process variants and future work are discussed, as well as large scale adaptations
and rapid prototyping. Finally, we outline the potential uses of this technology in flexible electronics, particularly in high
Current MEMS technology is perhaps reminiscent of the early semiconductor technology industry and the first computer systems. As technologies mature, a certain pattern of evolution typically ensues. This path, however, is fraught with challenges (e.g. efficient architectural exploration), which act as discontinuities in the advancement of a technology. Overcoming these obstacles requires innovations and, generally, the establishment of infrastructure. This paper proposes one vision for the future of MEMS technology, describing how the techniques employed in circuit and computing system design can be adapted to MEMS platform design to raise the level of abstraction and facilitate the creation of complex architectures.