Microadditive Manufacturing Technologies of 3D Microelectromechanical Systems

Abstract

Conventional microfabrication processes have been well established, but their capabilities are generally limited simple and 2D extruded geometries. Additive manufacturing allows the ability to manufacture true 3D complex geometries, rapid design for manufacturing, mass customization, materials savings, and high precision, which have triggered the increased interest in manufacturing microelectromechanical systems (MEMS). Herein, MEMS manufacturing's recent advancements, including both conventional and additive manufacturing technologies, their working principles, and practical capabilities are consolidated. The use of additive manufacturing in several MEMS areas such as in microelectronics, circuitry, microfluidics, lab on a chip, packaging, and structural MEMS is also discussed in detail. Furthermore, the potentials and limitations of additive manufacturing are investigated with regard to the MEMS requirements. Finally, the technology outlook and improvements are discussed. This study shows that additive manufacturing offers a promising future for the fabrication of MEMS, especially using high‐resolution techniques such as microstereolithography, materials jetting, and materials extrusion. In contrast, current challenges such as materials requirements, equipment innovation, fabricating of in vivo devices for biomedical applications, inherited defects and poor surface finish, adhesion to substrates, and productivity are areas that require further study to increase the uptake by the MEMS community.

Electrochemical Microneedles: Innovative Instruments in Health Care

“…The two-step soft lithography technology and the two-photon polymerization technology can provide high resolution and repeatability, but possess high manufacturing cost and complex steps, and the maximum manufacturability height of the microneedle array prepared by the two-step soft lithography technology is limited. As an important part of the preparation process of electrochemical microneedles, the preparation of microneedle electrodes has been rapidly developing along with the progress of microelectromechanical technology [ 32 ], and an increasing number of preparation processes and materials are emerging. Common microneedle electrode preparation materials are divided into three categories: polymers, metals, and silicon.…”

Micro 3D printing of a functional MEMS accelerometer

“…Recently, they have also been introduced in the manufacturing of final components in many sectors, such as automotive 3 and avionics 4 , especially where complex component geometries and low manufacturing volumes are needed. More recently, different 3D printing techniques have been used to realize functional macro- and mesoscale sensor devices 5 , 6 . Among them, macroscale inertial sensors have been fabricated using fused filament fabrication 7 , 8 , laser powder bed fusion 9 , and stereolithography 10 – 12 .…”

“…These devices have footprints of several mm 2 up to several cm 2 , and therefore they are not suitable for applications where miniaturization is critical. The footprint reduction of these types of 3D-printed sensor devices remains challenging because of the intrinsic limitations of the used 3D printing techniques, which can at best achieve dimensions as small as tens or hundreds of micrometers 5 , 6 , thereby setting a practical limit to the miniaturization and precision of the sensors, along with the related bandwidth limitations.…”

“…Among the 3D printing techniques suitable for realizing microscale devices, two-photon polymerization, also referred to as multiphoton polymerization or direct laser writing, is well suited for printing MEMS devices. 3D printing by two-photon polymerization offers resolutions of below 1 µm in all spatial directions 6 , 13 , matching and in some cases overcoming the resolution of cleanroom-based lithographic processes. Such a high resolution is critical in the realization of MEMS devices; hence, this technology has been used to realize microfluidic circuits 14 , optical devices 15 , and scaffolds for tissue engineering 16 .…”

Direct Writing of 3D Micro/Nanostructures Based on Nanoscale Strong Electric Field of Electron Beam

“…Due to their unique physical properties, 3D micro/nanostructures show broad application prospects in the fields of integrated circuits (ICs), [1][2][3] metamaterials, [4][5][6] energy conversion and storage, [7,8] micro electro mechanical systems, [2,9,10] and so on. For example, field-effect transistor (FET) with 3D structural features (Fin FET and gate-all-around FET) and their 3D integration can skillfully solve the problems of power consumption [1,2] and short channel effects [1,3] in high-density integration, becoming the mainstream trend in ICs.…”