NIL - a low-cost and high-throughput MEMS fabrication method compatible with IC manufacturing technology (original) (raw)
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Journal of Micromanufacturing, 2019
The recent success of additive manufacturing processes (also called, 3D printing) in the manufacturing sector has led to a shift in the focus from simple prototyping to real production-grade technology. The enhanced capabilities of 3D printing processes to build intricate geometric shapes with high precision and resolution have led to their increased use in the fabrication of microelectromechanical systems (MEMS). The 3D printing technology has offered tremendous flexibility to users for fabricating custom-built components. Over the past few decades, different types of 3D printing technologies have been developed. This article provides a comprehensive review of the recent developments and significant achievements in most widely used 3D printing technologies for MEMS fabrication, their working methodology, advantages, limitations, and potential applications. Furthermore, some of the emerging hybrid 3D printing technologies are discussed, and the current challenges associated with the 3D printing processes are addressed. Finally, future directions for process improvements in 3D printing techniques are presented.
Journal of Physics: Conference Series, 2006
X-ray lithography is an established technique for the micro fabrication of MEMS and MOEMS well known for low sidewall surface roughness, submicron critical dimension, and high aspect ratio. Recently the typical characteristics of this technique has been developed approaching new opportunities deriving by the possibility to perform tilted exposure and by the combined use with electron beam lithography that allow to shape with direct patterning already the final material in 3D micro and nanostructures. The general approach is to concentrate the complexity of the multi layer fabrication process required to obtain 3D nanostructures mostly on the lithographic process. This capability represent a micro-and nanofabrication tool enabling new technologies. In this paper will be shown a multiple-tilted X-ray lithography procedure combined with e-beam lithography to create sub-micrometric patterns of arbitrary shape buried in 3D structure. The use of deep x-ray lithography in multi exposure configuration has been also exploited for the production of biodegradable 3D scaffold structures and of micro needles based transdermal delivery tools fabrication.
A Moiré method for high accuracy alignment in nanoimprint lithography
Microelectronic Engineering, 2007
Nanoimprint lithography (NIL) is a cost efficient technique for the mass production of nanostructures. We demonstrate alignment accuracies in the range of 100 nm and below in UV-based nanoimprint lithography (UV-NIL) using a simple optical technique. The advantages of this technique are the relative simplicity of the marker-design and the whole setup combined with the possibility of an upgrade of existing equipment and still ultra-high precision alignment capabilities.
Front-to-back alignment techniques in microelectronics/MEMS fabrication: a review
Sensor Letters, 2006
The front-to-back alignment technique in photolithography process is often required for registering mutually aligned patterns on both the sides of the wafer in the fabrication process of power devices such as power transistors and various kinds of microelectromechanical systems (MEMS) based devices such as RF MEMS components, mechanical sensors, bio/chemical sensors, microcalorimeters, and microfluidic devices etc. This paper reviews the progress made in the front-to-back alignment techniques in semiconductor processing for the realization of microstructures for MEMS and other microelectronics devices. Various techniques, which are used in commercial front-to-back mask aligners, are discussed in detail. Some other alternative methods, which use the conventional contact/proximity single sided mask aligner for defining the mutually aligned patterns on both the sides of the wafers, are also covered in this review. The principle and approach of various front-toback alignment techniques have been presented. The alignment accuracy and the source of errors have been discussed. A list of the references which incorporate front-to-back alignment methods for the development of MEMS/microelectronics devices such as, mechanical sensors, bio/chemical sensors, microcalorimeters, RFMEMS components, microfluidic devices, power transistors is also included.
International Journal of Nanotechnology, 2014
Recent developments in flexible electronics, solar cells, displays, bio-chips and wearable technology have featured various micro/nanostructures in system designs. However, fabricating these micro/nanostructures on flexible substrates using existing technology such as photolithography, electron beam lithography (EBL) and other lithography techniques is troublesome, time consuming and costly. An in-house roll-to-roll ultraviolet nanoimprint lithography (R2R-UVNIL) system was designed and fabricated as an alternative low cost and large area patterning tool. It consists of a coating unit, soft-bake unit and imprinting unit which are connected together using a series of rollers. The aim of the integrated soft-bake stage was to minimise the mould sticking issues during the continuous R2R imprinting using solvent-based resist. The assembled R2R-UVNIL system was tested with imprinting process on an untreated commercial polyethylene terephthalate (PET) film as the flexible substrate, solvent-based SU8-2002 photopolymer as the resist and PDMS soft mould as the imprinting mould. The PDMS soft mould was replicated from an EBL patterned silicon master mould. Imprinting speeds of 50 to 150 mm/min have been achieved in this work, with relatively sound replication quality and formability for patterning sub-2 µm microstructures.
Advanced Techniques in 3D Photolithography for MEMS
2006
Three dimensional (3D) MEMS fabrication is essential to many power MEMS applications important to today's soldier. We present two advanced techniques to realize 3D structures in photoresist. Both technologies are based on gray-scale photolithography, which is a method to modulate the light intensity incident on photoresist to control the development rate. We compare a commercial technique, HEBS glass, to a technique developed in-house called double-exposure gray-scale. HEBS glass has a better horizontal resolution and is more suited to small structures that require high vertical resolution. Doubleexposure gray-scale technology has a comparable vertical resolution to HEBS glass, but is better suited to large MEMS structures over 100µm.
Nanoimprint lithography: An old story in modern times? A review
Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures, 2008
Nanoimprint lithography ͑NIL͒ is a high throughput, high-resolution parallel patterning method in which a surface pattern of a stamp is replicated into a material by mechanical contact and three dimensional material displacement. This can be done by shaping a liquid followed by a curing process for hardening, by variation of the thermomechanical properties of a film by heating and cooling, or by any other kind of shaping process using the difference in hardness of a mold and a moldable material. The local thickness contrast of the resulting thin molded film can be used as a means to pattern an underlying substrate on wafer level by standard pattern transfer methods, but also directly in applications where a bulk modified functional layer is needed. Therefore it is mainly aimed toward fields in which electron beam and high-end photolithography are costly and do not provide sufficient resolution at reasonable throughput. The aim of this review is to play between two poles: the need to establish standard processes and tools for research and industry, and the issues that make NIL a scientific endeavor. It is not the author's intention to duplicate the content of the reviews already published, but to look on the NIL process as a whole. The author will also address some issues, which are not covered by the other reviews, e.g., the origin of NIL and the misconceptions, which sometimes dominate the debate about problems of NIL, and guide the reader to issues, which are often forgotten or overlooked.
MIT-OSU-HP Focus center on non-lithographic Technologies for MEMS and nEMS
This newly formed center is part of an overall set of centers on MEMS/NEMS fundamentals supported by DARPA. The MIT-OSU-HP Focus Center aims to develop new methods for fabrication of MEMS and NEMS that do not use conventional lithographic methods. The Center leverages the leading expertise of MIT and OSU in MEMS and printed devices, with the printing expertise of HP. The focus center is organized into four primary areas: tools, materials and devices, circuits, and demonstration systems.
28 Three-Dimensional Patterning using Ultraviolet Nanoimprint Lithography
2017
Although an extensive number of publications have been reported on nanoimprint lithography (NIL) techniques, the ability of NIL for three-dimensional (3-D) patterning has not been fully addressed in terms of the mold fabrication and imprint processes. Developing technologies for patterning 3-D and multilevel features are important because they eliminate multiple steps and complex interlevel alignments in the fabrication process of nanoscale devices and structures. The semiconductor industries through the International Technology Roadmap for Semiconductor (ITRS) organization have identified NIL (ITRS 2003; ITRS 2008), especially ultraviolet curable nanoimprint lithography (UV-NIL) as a strong candidate for the next generation lithography (NGL) technology for nodes down to 5 nm. Three dimensional NIL (3D-NIL) will have a variety of practical applications including generating patterns for MEMS and NEMS devices, on-chip optics, antireflection structures and in biochip reactors. This cha...