Design and Applications of Coordinate Measuring Machines

Coordinate measuring machines (CMMs) have been conventionally used in industry for 3-dimensional and form-error measurements of macro parts for many years. Ever since the first CMM, developed by Ferranti Co. in the late 1950s, they have been regarded as versatile measuring equipment, yet many CMMs on the market still have inherent systematic errors due to the violation of the Abbe Principle in its design. Current CMMs are only suitable for part tolerance above 10 μm. With the rapid advent of ultraprecision technology, multi-axis machining, and micro/nanotechnology over the past twenty years, new types of ultraprecision and micro/nao-CMMs are urgently needed in all aspects of society. This Special Issue accepted papers revealing novel designs and applications of CMMs, including structures, probes, miniaturization, measuring paths, accuracy enhancement, error compensation, etc. Detailed design principles in sciences, and technological applications in high-tech industries, were required for submission. Topics covered, but were not limited to, the following areas: 1. New types of CMMs, such as Abbe-free, multi-axis, cylindrical, parallel, etc. 2. New types of probes, such as touch-trigger, scanning, hybrid, non-contact, microscopic, etc. 3. New types of Micro/nano-CMMs. 4. New types of measuring path strategy, such as collision avoidance, free-form surface, aspheric surface, etc. 5. New types of error compensation strategy

Tactile 3D probing system for measuring MEMS with nanometer uncertainty : aspects of probing, design, manufacturing and assembly

Measurement underpins manufacturing technology, or in more popular terms: when you cannot measure it, you cannot manufacture it. This is true on any dimensional scale, so for microand nanotechnology to deliver manufactured products it must be supported by reliable metrology. Component miniaturization in the field of precision engineering and the development of micro electromechanical systems (MEMS) thus results in a demand for suitable measurement instruments for complex three-dimensional components with feature dimensions in the micrometer region and associated dimensional tolerances below 100 nm. As will be discussed in the first chapter of this thesis, several ultra precision coordinate measuring machines (CMMs) are developed. These CMMs are suitable for measuring complex threedimensional products, like MEMS and other miniaturized components. From a discussion on available probe systems in the first chapter it is apparent that, with respect to measurement uncertainty and applicability of measurements on MEMS and other miniaturized components, the performance of ultra precision CMMs is currently limited by the performance of available probe systems. The main reason is that the measurement using a probe system is not purely influenced by work piece topography, but also by interaction physics between probe tip and work piece. As the dimensional scale of the measurement decreases, the problems associated with this interaction become increasingly apparent. Typical aspects of this interaction include the influence of contact forces on plastic deformations in the contact region, surface forces and geometric and thermal effects. The influence of these aspects on the measurement result is discussed in the second chapter. This chapter will combine results from literature, simulation and experimental results to discuss the aspects that influence the measurement result in tactile probes. From these results it will become apparent that these aspects underlie the limitation for precision measurements on miniaturized components using tactile CMM metrology. As a result, these interaction aspects are the main challenge when designing ultra precision probes. The analysis of the interaction physics is used in the design of a novel silicon probing system with integrated piezo resistive strain gauges to measure a displacement of the probe tip. The result is a probe system with a colliding mass of 34 mg and an isotropic stiffness at the probe tip with a stiffness down to 50 N/m. The measurement range of the probing system is 30 µm, but in most measurements a range of 10 µm is used which slightly improves the signal to noise ratio. Calibration results using the planar differential laser interferometer setup as discussed in chapter 1 show a standard deviation of 2 nm over 2000 measurement points taken in a 6 hour time frame over a repeated 5.5 µm displacement. The combined 3D uncertainty of the probing system is estimated to be 17.4 nm. In order to measure micrometer scale structures, including holes and trenches, the probing system can be equipped with micrometer scale probe tips. The main limitation is the relative stiffness between the stylus and the suspension of the probing system. By design optimization, a ratio between the length and radius of the measurement part of the stylus of 50 can be obtained, making the probing system highly suitable for measuring these micrometer scale structures. So far, probe tips with a radius of 25 µm have been manufactured and work is being done to decrease this radius even further. The probing system is implemented on a high-accuracy coordinate measuring machine and is suitable for three-dimensional tactile measurements on miniaturized components with nanometer uncertainty. A main limitation when manufacturing the probe is assembly of the probe tip, stylus and chip which is discussed in chapter 4. Assembly of the probe is investigated in a series of experiments on an automated assembler. Based on these results, the design of the probe is optimized for assembly and the automated assembler is made suitable for assembly of the probe by implementation of a novel suction gripper. This resulted in an improvement in placement uncertainty at the tip by a factor of 10 and an increase in yield during assembly from 60 - 80% initially, to over 95%. In chapter 5 several experimental results with the probe system are discussed, including a quantification of the effects of surface forces on tactile measurements. It is shown that these effects are highly repeatable and result in an attraction of 40 µN and 60 µN in the xy- and z-direction, respectively. Moreover, it is shown that the influence of surface forces on a measurement in the xy-plane can be observed for a separation of 500 µm or less. Finally, conclusions and recommendations for further research are discussed in chapter 6

Micro- and nanotechnology for cell biophysics

Procedures and methodologies used in cell biophysics have been improved tremendously with the revolutionary advances witnessed in the micro- and nanotechnology in the last two decades. With the advent of microfluidics it became possible to reduce laboratory-sized equipment to the scale of a microscope slide allowing massive parallelization of measurements with extremely low sample volume at the cellular level. Optical micromanipulation has been used to measure forces or distances or to alter the behavior of biological systems from the level of DNA to organelles or entire organisms. Among the main advantages is its non-invasiveness, giving researchers an invisible micro-hand to “touch” or “feel” the system under study, its freely and very often quickly adjustable experimental parameters such as wavelength, optical power or intensity distribution. Atomic force microscopy (AFM) opened avenues for in vitro biological applications concerning with single molecule imaging, cellular mechanics or morphology. As it can operate in liquid environment and at human body temperature, it became the most reliable and accurate nanoforce-tool in the research of cell biophysics. In this paper we review how the above three techniques help increase our knowledge in biophysics at the cellular level

Cutting Edge Nanotechnology

The main purpose of this book is to describe important issues in various types of devices ranging from conventional transistors (opening chapters of the book) to molecular electronic devices whose fabrication and operation is discussed in the last few chapters of the book. As such, this book can serve as a guide for identifications of important areas of research in micro, nano and molecular electronics. We deeply acknowledge valuable contributions that each of the authors made in writing these excellent chapters

Incorporating nanomaterials with MEMS devices.

This dissertation demonstrates an elegant method, known as \u27micro-origami\u27 or strain architecture to design and fabricate three-dimensional MEMS structures which are assembled using actuation of a metal-oxide bilayer with conventional planar lithography. Folding allows creating complex, robust, three-dimensional shapes from two-dimensional material simply by choosing folds in the right order and orientation, small disturbances of the initial shape may also be used to produce different final shapes. These are referred to as pop-up structures in this work. The scope of this work presented the deposition of colloidal gold nanoparticles (GNPs) into conformal thin films using a microstenciling technique. Results illustrated that the gold nanoparticle deposition process can easily be integrated into current MEMS microfabrication processes. Thin films of GNPs deposited onto the surfaces of siliconbased bistable MEMS and test devices were shown to have a significant effect on the heating up of microstructures that cause them to fold. The dissertation consists of four chapters, covering details of fabrication methods, theoretical simulations, experimental work, and existing and potential applications. Chapter II illustrates how control of the folding order can generate complex three-dimensional objects from metal-oxide bilayers using this approach. By relying on the fact that narrower structures are released from the substrate first, it is possible to create multiaxis loops and interlinked objects with several sequential release steps, using a single photomask. The structures remain planar until released by dry silicon etching, making it possible to integrate them with other MEMS and microelectronic devices early in the process. Chapter III depicts the fabrication process of different types of bistable structures. It describes the principle of functioning of such structures, and simulations using CoventorWare are used to support the concept. We talk over about advantages and disadvantages of bistable structures, and discuss possible applications. Chapter IV describes fabrication procedure of nanoparticle-MEMS hybrid device. We introduce a convenient synthesis of GNPs with precisely controlled optical absorption in the NIR region by a single step reaction ofHAuCl4 and Na2S203. We take a look at different techniques to pattern gold nanoparticles on the surface of MEMS structures, and also provide a study of their thermal properties under near IR stimulation. We demonstrate the first approach of laser-driven bistable MEMS actuators for bioapplications. Finally, in Conclusion discuss the contributions of this dissertation, existent limitations and plans of the future work

Mechanical resonating devices and their applications in biomolecular studies

To introduce the reader in the subjects of the thesis, Chapter 1 provides an overview on the different aspects of the mechanical sensors. After a brief introduction to NEMS/MEMS, the different approaches of mechanical sensing are provided and the main actuation and detection schemes are described. The chapter ends with an introduction to microfabrication. Chapter 2 deals with experimental details. In first paragraph the advantages of using a pillar instead of common horizontal cantilever are illustrated. Then, the fabrication procedures and the experimental setup for resonance frequencies measurement are described. The concluding paragraph illustrates the technique, known as dip and dry, I used for coupling mechanical detection with biological problems. In Chapter 3, DNA kinetics of adsorption and hybridization efficiency, measured by means of pillar approach, are reported. Chapter 4 gives an overview of the preliminary results of two novel applications of pillar approach. They are the development of a protein chip technology based on pillars and the second is the combination of pillars and nanografting, an AFM based nanolithography. Chapter 5 starts with an introduction about the twin cantilever approach and of the mechanically induced functionalization. Fabrication procedure is described in the second paragraph. Then the chemical functionalizations are described and proved. Cleaved surface analyses and the spectroscopic studies of the mechanically induced functionalization are reported. In Appendix A there is an overview of the physical models that are used in this thesis

Polymer Pen Printing: A Tool for Studying 2D Enzymatic Lithography and Printing 3D Carbon Features

Polymer Pen Lithography (PPL) is a promising molecular printing approach which combines the advantages of both microcontact printing (low cost, high-throughput) and the dip pen lithography (DPN) (arbitrary writing, high-resolution) into one cohesive lithography method to create 2 dimensional (2-D) patterns with micro/nano-features on different substrates. The goal of this dissertation is to design and develop a new tool based upon PPL, which is not limited to forming 2D parallel patterns, but can also create 3D complex microstructures, finding applications in both biotechnology and Micro-Electro-Mechanical systems (MEMS) technology. This novel approach is named Polymer Pen Printing. Different from PPL using traditional dry-ink printing methods, an inking step is added to each printing repetition in the polymer pen printing process. Thus a wide range of ink materials with diverse viscosities can be transferred to substrates to create functional 2D and 3D microstructures. The polymer pen printing apparatus used in this thesis has been accomplished and introduced in Chapter 2. As a preliminary attempt, the single polymer pen printing approach was developed by simply attaching a solid polydimethylsiloxane (PDMS) pen tip to a multi-axis robot for small microarray fabrication. Compared to the single pen printing method, multi-pen printing can create large arrays of features. Therefore, an improved apparatus for polymer pen printing with high-throughput was discussed and built. Silicon molds, which consist of hundreds of uniform pyramidal openings, were photolithographically defined and etched using hydrofluoric acid (HF) followed by potassium hydroxide solution; after surface-modification with fluorosilane, these silicon molds were used to cast arrays of PDMS pyramidal pen tip. The cast PDMS pen array was mounted to a hollow holder with a 45° mirror inside. Therefore, each PDMS pen can be observed and monitored from the microscope on the side. To achieve prints less than 1 micron across, a Z axis stage with nanometer resolution was incorporated; and to control the compression of PDMS pen tips, a force gauge was also incorporated to detect 1 mg of applied force from the tips. The printing process for the multi-pen system is almost the same as single pen system. PDMS pens are coated with ink solution before each printing cycle by dipping into an inkwell and then brought into contact with the substrate surface. Thus multiple patterns, one from each tip, are created in parallel simultaneously. Furthermore, with control of the printing force, feature sizes could be controlled over the range submicron to tens of microns. Three ink candidates have been printed by polymer pen printing approach to fabricate 2D&3D microstructures. The first ink material is Barium Strontium Titanate (BST) nanocrystallites dispersed in a furfuryl alcohol (FA), which was printed by the single PDMS pen with 100 μm tip diameter (Chapter 3). After printing, samples were heated to crosslink FA monomers, forming a stable polymeric matrix with embedded BST nanocrystallites. Without shear-thinning properties, BST/FA ink cannot be used to build 3D posts, but it has the capability to create circular patterns with different thickness by the single or multi-tier deposition method. It was found that the thickness of film increased linearly with the number of deposits without changing the diameter significantly. This encouraging result could enable the formation of microcapacitors with multi-tiered structure. Moreover, the study of printing parameters, including printing height and ink pick-up position, shows that changes to the pen positions in the ink reservoir or substrate have essentially no impact on deposit thickness or diameter. Beyond that, the effect of surface chemistry of PDMS pen and silicon wafer have also been studied. The plasma treated hydrophilic PDMS pen can pen transfer more BST/FA than untreated one; and the larger diameters with smaller thickness were obtained on a hydrophilic silicon wafer. The second ink candidate is a dilute aqueous solution of enzyme Candia antartica lipase B (CALB), which is known to catalyze the decomposition of poly (ε-caprolactone) (PCL) films. By bringing enzymes into contact with pre-defined regions of a surface, a polymer film can be selectively degraded to form patterned features that are requited for applications in biotechnology and electronics. This so-called enzymatic lithography is an environmentally friendly process as it does not require any actinic radiation or synthetic chemicals to develop required features. But the need to restrict the mobility of the enzyme in order to maintain control of feature sizes poses a significant challenge. In Chapter 4, after writing 2D enzyme patterns onto a spin-cast PCL film by single pen printing, samples with CALB were incubated at 37 ℃ and 95% relative humidity (RH) for up to 7 days to develop features. The CALB selectively degraded the PCL film during incubation, forming openings through the film. The size of these features (10 to 50 μm diameter) is well suited for use as biocompatible micro-reactors. Previous study of patterning CALB by single polymer pen printing technique resulted in slow etch rates, low throughput and poor image quality. In Chapter 5, I present an improved enzymatic lithography approach, still based on enzyme CALB and PCL system, which can resolve fine-scale features (\u3c 1 μm across) in thick (0.1 - 2.0 μm) polymer films after 5 minutes to 2 hours of incubation at 37 ℃ and 87% RH. Immobilization of the enzyme on the polymer surface was monitored using fluorescence microscopy by labeling CALB with FITC. The crystallite size in the PCL films was systematically varied; small crystallites resulted in significantly faster etch rates (20 nm/min) and the ability to resolve smaller features (as fine as 1 μm). The effect of printing conditions and RH during incubation is also presented. Patterns formed in the PCL film were transferred to an underlying copper foil demonstrating a Green approach to the fabrication of printed circuit boards. In parallel, the third ink material is a mixture of 25 wt% graphite dispersed in a high viscosity phenolic resin n-methyl-2-pyrrolidone (NMP) solution, which can be converted into carbon/carbon composites after a pyrolysis process. The 3D polymeric posts were created by depositing multilayers of thixotropic phenolic ink on a silicon substrate by single polymer pen printing method with a 10 μm radius PDMS pen tip (Chapter 6). After pyrolysis at 1000 ℃ in a nitrogen (N2) atmosphere, the polymeric features were converted to the glassy carbon/graphite features with a high aspect ratio (\u3e2). These features may be used as microelectrodes. Last, arrays of needle-shaped glassy carbon have been developed by a drawing approach using multi-pen printing technique followed by simple pyrolysis process (Chapter 7). To build polymeric needles with ultra-high aspect ratio, the polymeric ink was prepared by dissolving phenolic resin in the high boiling point (204 ℃) solvent NMP without fillers to achieve good printability and suitable viscosity. By slowly lifting up the print head from substrate, liquid needle structures were formed and then solidified on silicon substrates or gold electrodes due to the solvent evaporation. In addition, suspended resin fibers connected to two electrodes have also been fabricated by precisely controlling the movement of the PDMS pen. After pyrolysis, these resin features were converted to glassy carbon and the 3D structures remained. The electrical characterization results showed that glassy carbon made by this method had relatively low resistivity (2.5 x 10-5 Ωm). Therefore the glassy carbon based microneedles are well-suited to be electrodes for electrochemical sensors for biological applications