P. Vettiger

Bio: P. Vettiger is an academic researcher from IBM. The author has contributed to research in topics: Photoresist & Resist. The author has an hindex of 2, co-authored 2 publications receiving 1166 citations.

SU-8: a low-cost negative resist for MEMS

Abstract: This paper describes the characterization of a home-made negative photoresist developed by IBM. This resist, called SU-8, can be produced with commercially available materials. Three blends were prepared for this article and some of its optical and mechanical properties are presented. One of its numerous advantages is the broad range of thicknesses which can be obtained in one spin: from 750 nm to with a conventional spin coater. The resist is exposed with a standard UV aligner and has an outstanding aspect ratio near 15 for lines and 10 for trenches. These ratios combined with the electroplating of copper allow the fabrication of highly integrated electromagnetic coils.

Fabrication of photoplastic high-aspect ratio microparts and micromolds using SU-8 UV resist

Abstract: An innovative method for fabrication and rapid prototyping of high-aspect ratio micromechanical components in photoresist is discussed. The photoresist is an epoxy-negative-tone resist, called SU-8, which can be structured to more than 2 mm in thickness by UV exposure. Small gears of 530 mu m in diameter and 200 mu m in thickness have been realized in this photoplastic and their functionality has been demonstrated. In addition a process called MIMOTEC(TM) (MIcroMOlds TEChnology) has been established for the fabrication of metallic micromolds. MIMOTEC(TM) is based on the use of the SU-8 spun on high thicknesses and electrodeposition of nickel. Thermoplastic microcomponents have been injected and mounted in watches.

Micro Total Analysis Systems. 1. Introduction, Theory, and Technology

Abstract: Review

An Introduction to Microelectromechanical Systems Engineering

Abstract: If you've not been involved in MEMS (MicroElectroMechanical Systems) technology or had the cause to use MEMS devices, then you may wonder what all the fuss is about. What are MEMS anyway? What's the difference between MEMS and MST (MicroSystems Technology)? What are the advantages over existing technologies? If you have ever found yourself pondering over such questions, then this book may be for you. As the title suggests, the main aim is to provide an introduction to MEMS by describing the processes and materials available and by using examples of commercially available devices. The intended readership are those technical managers, engineers, scientists and graduate students who are keen to learn about MEMS but have little or no experience of the technology. I was particularly pleased to note that Maluf has dedicated a whole chapter to the important (and often difficult) area of packaging. The first three chapters provide a general overview of the technology. Within the first three pages we are introduced to the MEMS versus MST question, only to discover that the difference depends on where you live! The United States prefer MEMS, while the Europeans use the handle MST. (Note to self: tell colleagues in MEMS group at Southampton). A good account is given of the basic materials used in the technology, including silicon, silicon oxide/nitride/carbide, metals, polymers, quartz and gallium arsenide. The various processes involved in the creation of MEMS devices are also described. A good treatment is given to etching and bonding in addition to the various deposition techniques. It was interesting to note that the author doesn't make a big issue of the differences between bulk and surface micromachined devices; the approach seems to be `here's your toolbag - get on with it'. One of the great strengths of this book is the coverage of commercial MEMS structures. Arising as they have, from essentially a planar technology, MEMS devices are often elaborate three-dimensional creations, and 2D drawings don't do them much justice. I have to say that I was extremely impressed with the many aesthetic isometric views of some of these wonderful structures. Pressure sensors, inkjet print nozzles, mass flow sensors, accelerometers, valves and micromirrors are all given sufficient treatment to describe the fundamental behaviour and design philosophy, but without the mathematical rigour expected for a traditional journal paper. Chapter 5 addresses the promise of the technology as a means of enabling a new range of applications. The concept of using MEMS devices as key elements within complex systems (or even microsystems!) is explored. The so-called `lab-on-a-chip' approach is described, whereby complex analytical systems are integrated onto a single chip together with the associated micropumps and microvalves. The design and fabrication of MEMS devices are important issues by themselves. A key area, often overlooked, is that of packaging. Painstaking modelling and intricate fabrication methodologies can produce resonator structures oscillating at precisely, say, 125 kHz. The device is then mounted in a dual-in-line carrier and the frequency shifts by 10 kHz because of the additional internal stresses produced. Packaging issues can't be decoupled from those of the micromachined components. Many of these issues, such as protective coatings, thermal management, calibration etc, are covered briefly in the final chapter. Overall, I found this book informative and interesting. It has a broad appeal and gives a good insight into this fascinating and exciting subject area. Neil White

Microelectromechanical systems (MEMS):fabrication, design and applications

Abstract: Micromachining and micro-electromechanical system (MEMS) technologies can be used to produce complex structures, devices and systems on the scale of micrometers. Initially micromachining techniques were borrowed directly from the integrated circuit (IC) industry, but now many unique MEMS-specific micromachining processes are being developed. In MEMS, a wide variety of transduction mechanisms can be used to convert real-world signals from one form of energy to another, thereby enabling many different microsensors, microactuators and microsystems. Despite only partial standardization and a maturing MEMS CAD technology foundation, complex and sophisticated MEMS are being produced. The integration of ICs with MEMS can improve performance, but at the price of higher development costs, greater complexity and a longer development time. A growing appreciation for the potential impact of MEMS has prompted many efforts to commercialize a wide variety of novel MEMS products. In addition, MEMS are well suited for the needs of space exploration and thus will play an increasingly large role in future missions to the space station, Mars and beyond. (Some figures in this article are in colour only in the electronic version)

High-aspect-ratio, ultrathick, negative-tone near-UV photoresist and its applications for MEMS

Abstract: Detailed investigations of the limits of a new negative-tone near-UV resist (IBM SU-8) have been performed. SU-8 is an epoxy-based resist designed specifically for ultrathick, high-aspect-ratio MEMS-type applications. We have demonstrated that with single-layer coatings, thicknesses of more than 500 μm can be achieved reproducibly. Thicker resist layers can be made by applying multiple coatings, and we have achieved exposures in 1200 μm thick, double-coated SU-8 resist layers. We have found that the aspect ratio for near-UV (400 nm) exposed and developed structures can be greater than 18 and remains constant in the thickness range between 80 and 1200 μm. Vertical sidewall profiles result in good dimensional control over the entire resist thickness. To our knowledge, this is the highest aspect ratio reported for near-UV exposures and the given range of resist thicknesses. These results will open up new possibilities for low-cost LIGA-type processes for MEMS applications. The application potential of SU-8 is demonstrated by several examples of devices and structures fabricated by electroplating and photoplastic techniques. The latter is especially interesting as SU-8 has attractive mechanical properties.