This PDF file contains the front matter associated with SPIE Proceedings Volume 8250, including the Title Page, Copyright information, Table of Contents, and the Conference Committee listing

Integration of MEMS and MOEMS requires very compact packages with short interconnects which are found in 3D packages. We will give an overview on assembly methods like chip-to-chip, chip-to-wafer and wafer-to-wafer. For the variety of applications different interconnection methods are shown: reflow soldering, transient liquid phase bonding and transient liquid phase soldering, thermocompression and thermosonic bonding as well as sintering of silver paste or new materials like nanosponge.

An investigation into the effects of dry plasma etching release process parameters, local wafer position and induced inplane stress on the yield of MEMS devices is presented. Several identical wafer quarters, each subjected to different releasing process conditions, are studied. Yield is evaluated by observational measurements of the stiction of MEMS nanocantilevers fabricated alongside with bent beam strain sensors. Results show that lower yield is found for larger processing times as well as higher releasing temperatures. On the other hand, yield improves when thicker nanocantilevers are released using the same processing parameters. The distribution of process-induced in-plane stress of PECVD silicon nitride films is shown to change widely from compressive to tensile based on the local wafer position, whereas no clear correlation between stiction and stress distribution is found. Viability of determining MEMS yield at the wafer-level based on process-induced residual stress is discussed. Other possible root causes of yield in MEMS due to dry plasma release etching are also briefly touched.

Transparent electrodes using carbon nanotube (CNT) have recently been studied as potential replacements for convention ITO. In this work, CNT or ITO coated polyethylene terephthalate (PET) samples were prepared and studied. The degree of cohesion is dependent on the drying conditions. To explore effects of changing surface conditions, three drying temperatures, 20 °C, 80 °C, and 120 °C, were used. Electrical resistance measures were used to evaluate the interfacial durability and electrical properties of prepared transparent electrodes. FE-SEM was used to investigate surface changes and UV-spectroscopy was used to evaluate transparency as functions of the different drying temperatures. The electronic properties for these nanoparticle coated surfaces were evaluated using a cyclic voltametry method. Interfacial durability was evaluated by static contact angle measurement changes with elapsed time. The pH values of the coatings were measured in a water solution. The durability of the CNT coated surfaces was found to be better than that of the ITO coated surfaces. The higher drying temperatures were found to produce better surfaces because of improved cohesion between the nanoparticles which resulted in improved electrical properties and improved durability of the coated surfaces.

This paper presents the results of an experimental study of electrothermal poly-Si MEMS structures wherein changes to the surface topography and material properties are observed due to use. The ex-situ AFM characterization reveals changes in the surface topography after cyclic actuation. The extent of topical SiO2 appears to increase with the number of actuation cycles and increasing stress levels on the polysilicon surfaces. The differences in the surface topography and oxide thickness are characterized as a function of fatigue cycling and in-situ annealing of the electrothermal actuators. FEA analyses were performed to evaluate the magnitude and distribution of stresses in the actuators to compare stress effects from oxide development on electrothermomechanical structures. With the observation of topographical changes, the intrinsic material property like resistivity was also affected. A change of 1.4% was seen for a 20% duty cycle, 3.1% for 50% duty cycle and 4.1% for 80% duty cycle. Similar experiments were performed for sealed devices in order to observe the changes in resistivity under inert conditions. A comparison of change in resistivity for sealed devices and nonsealed devices was done. Finally, force-distance curves were plotted to ascertain the adhesion forces for the actuator surfaces before and after actuation. The adhesion forces increases from ~7nN (un-actuated chevron) to ~40nN (10,000 cycles).

Planar refractive microlens arrays (MLAs) with high fill-factor were developed utilizing polymer replication technique. By using isotropically wet-etched quartz as a master mold, we obtained uniformly arrayed plano-concave patterns on poly(dimethylsiloxane) (PDMS) with a pitch, height, and radius of curvature of 132, 60, and 104.5 μm, respectively. A high refractive index polymer was coated on the patterned PDMS as a light refraction layer. The measured focal length of the fabricated MLA was about 900 μm, showing well correspondence with the simulated one. The diameter of the focused beam spots was 5.4 μm, denoting the excellent light focusing ability.

We present an experimental method to study field structures of highly confined light after interaction with microstructures. A high-resolution interference microscope (HRIM) allows us to measure the three-dimensional (3D) amplitude and phase distributions of light emerging from the sample. While the amplitude fields represent conventional pictures of light confinements like a hotspot, the phase fields exhibit peculiar behaviors, which are of significant interest. Longitudinal-differential interferometry can directly visualize and quantify phase deviations in 3D space with respect to a plane wave of the same frequency serving as a reference. The phase fields near the confinement exhibits particular phase features, e.g., axial phase anomaly and superluminal phase velocity. As example of the light interaction with microstructures, two specific optical phenomena have been investigated here: Gouy phase anomaly in the photonic nanojet and superluminal phase propagation of the spot of Arago. For the first time, we could experimentally demonstrate high-resolution axial phase measurements of such phenomena generated by microstructures of wavelengthscale size and at visible light with 642-nm wavelength.

Scanning White Light Interferometry (SWLI) provides high vertical precision for measuring step-like structures in microelectromechanical systems (MEMS). The SWLI performance depends on its light source. A rapidly modulated light source with a broad bandwidth inside the infrared (IR) region is necessary to measure layered MEMS that move. Typical SWLI light sources - light emitting diodes (LEDs) and Halogen (HG) bulbs - fulfill only one of these requirements. To overcome this shortcoming we equipped our SWLI setup with a supercontinuum (SC) light source produced by Fiberware Gmbh (Ilum 100 USB II). We tested our setup by measuring in plane and out of plane oscillating thermal bridges with visible light, as well as top and bottom surfaces of silicon structures using IR light. The wide SC spectrum creates localized interferograms. This allowed us to measure top and bottom surfaces of a thin (4 μm) bridge. The stroboscopically measured profiles of oscillating thermal bridges were comparable to those measured using a white LED. The results of static measurements were similar to those achieved with an HG lamp.

Ceramic column grid array (CCGA) packages have been increasing in use based on their advantages such as high interconnect density, very good thermal and electrical performances, compatibility with standard surfacemount packaging assembly processes, and so on. CCGA packages are used in space applications such as in logic and microprocessor functions, telecommunications, payload electronics, and flight avionics. As these packages tend to have less solder joint strain relief than leaded packages or more strain relief over lead-less chip carrier packages, the reliability of CCGA packages is very important for short-term and long-term deep space missions. We have employed high density CCGA 1152 and 1272 daisy chained electronic packages in this preliminary reliability study. Each package is divided into several daisy-chained sections. The physical dimensions of CCGA1152 package is 35 mm x 35 mm with a 34 x 34 array of columns with a 1 mm pitch. The dimension of the CCGA1272 package is 37.5 mm x 37.5 mm with a 36 x 36 array with a 1 mm pitch. The columns are made up of 80% Pb/20%Sn material. CCGA interconnect electronic package printed wiring polyimide boards have been assembled and inspected using non-destructive x-ray imaging techniques. The assembled CCGA boards were subjected to extreme temperature thermal atmospheric cycling to assess their reliability for future deep space missions. The resistance of daisy-chained interconnect sections were monitored continuously during thermal cycling. This paper provides the experimental test results of advanced CCGA packages tested in extreme temperature thermal environments. Standard optical inspection and x-ray non-destructive inspection tools were used to assess the reliability of high density CCGA packages for deep space extreme temperature missions.

A MEMS tribogauge was used for on-chip and in-situ characterization of nano-tribological phenomena (stiction, friction, and wear of coated polysilicon surfaces). The device was fabricated using the SUMMiT-V process. Measurements were made on sidewall surfaces on the polysilicon-3 layer. The device consists of two orthogonally positioned comb-drive assemblies that are used for both actuation and sensing. One assembly is used to apply a normal load (F_n) to contacting surface, while the other induces a tangential load (F_T). Precise position control is tracked by employing a LabVIEW controlled AD7747 capacitance sense mechanism. The resolution of the characterization apparatus is ±10nm. Three MEMS tribogauge devices are tested; two of them have a chemisorbed layer of self-assembled monolayer (SAM) coatings and one with no SAM coating. The two types of SAM coatings are FOTS and 'Sandia vapor-SAM' (SVSAM). The tribogauge with no FSAM coating is either UV-Ozone or 'air plasma' treated to remove organic contaminants leaving behind -OH bonds on top of the MEMS surface (native oxide, SiO₂). Characterization using the tribogauge for each coating type includes: measurement of baseline stiction force [see manuscript], static and dynamic coefficient of friction [see manuscript], induced stiction force calculated after specific load cycles [see manuscript]. Experiments showed that the induced stiction force increases in proportion to the increase in the number of load cycles, indicating degradation of the FSAM coating and topographical changes to the interacting surfaces. The UV-Ozone /air plasma treated pristine tribogauge was used to measure the stiction force of the device with no SAM coating [see manuscript].

A chemisorbed fluorocarbon self-assembled monolayer (FSAM) layer on MEMS surfaces can greatly improve MEMS device reliability by reducing the in-use stiction force. In this work, a MEMS tribogauge that measures stiction force between two interacting surfaces has been used for FSAM coating and process parameter characterization. A commercially available nanocoating tool was used for depositing FSAM coatings. Five different coating recipes with different injection times for the FSAM precursor were evaluated with the tribogauge. The interacting surfaces of the tribogauge were exposed to many load cycles. These experiments allowed a preferred process to be determined.

The world of leak testing, and the applicable physics, is unsettled. While globally lower MIL-STD leak rate criteria are under consideration even for 1 atm-large volume packages, industry is conversely moving rapidly into very small volume MEMS and vacuum packaging for advanced devices. These changes point out serious conceptual disconnects between the reality of properly characterizing a leak and the conceptual tools used to ensure the desired lifetime. The physical understandings and associated tool sets used to test and model the leaks are described. We modeled two actual packages, a large, ≈200 cc volume multichip module for aerospace applications and a small ≈0.01cc volume MEMS package for sensor applications. Impacts of various physical models of leak flow into a package are compared to include Fickian Diffusion, The Davy Model, Howl-Mann, and an empirically derived model based on Kr-85 leak testing as called out in the most recent edition of MIL-STD-883. As shown in the comparisons, simple He leak testing and physical models based thereon fall apart in the small volume MEMS packaging space.

Future applications of miniaturized space systems will have special needs on MEMS components. This paper addresses the needs, status and perspectives of the MEMS technology for miniaturized space system from the perspective of a spacecraft developer. First, the needs of future space missions on MEMS components are discussed. Then, the state-of-the- art MEMS technologies are reviewed based upon these needs. Finally, perspectives of space-based MEMS technology will be addressed based on the analysis of both future mission needs and technological trends.

Next-generation astronomical instrumentation for ground-based and space telescopes could use MOEMS devices. Among them, Multi-Object Spectrographs (MOS) are the major instruments for studying primary galaxies and remote and faint objects. A promising solution for the object selection system is the use of MOEMS devices such as micromirror arrays (MMA) which allow the remote control of the multi-slit configuration in real time. We are engaged in a European development of MMA for generating reflective slit masks. Prototypes of MMA with 2048 individually addressable micromirrors made of single-crystal silicon were successfully designed, fabricated and tested. 100×200μm² micromirrors can be tilted by electrostatic actuation yielding 24° mechanical tilt-angle. The micromirrors were successfully actuated before, during and after cryogenic cooling at 162K. Line-column addressing for individual mirrors has also been demonstrated. We were also engaged in a technical assessment of using a 2048 × 1080 DMD from Texas Instruments for space applications. For a MOS in space, the device should work in vacuum and at low temperature. Our tests reveal that the DMD remains fully operational at -40°C and in vacuum. A 1038 hours life test in space survey conditions, Total Ionizing Dose radiation, thermal cycling and vibrations/shocks have also been successfully completed. These results do not reveal any show-stopper concerning the ability of the DMD to meet environmental space requirements. These developments and tests demonstrate the full ability of this type of components for space instrumentation, especially in multi-object spectroscopy applications.

There is a demand for increasing the spatial resolution and swath width in Earth observation applications. To improve the resolution and swath width, increased thermal isolation and decreased pitch of the microbolometer need to be achieved. This paper reports on the investigation of different structures of highly insulated 35 μm pitch microbolometers. Each structure consists of two suspended Si₃N₄ platforms with the upper level containing the bolometer element and the lower level containing hinges of varying length. A numerical model was derived to predict the figures of merit of the structures prior to microfabrication. Experimental characterization was performed on microfabricated devices, confirming the computed results. The thermal conductance, in the range from 85 to 134 nW/K, varies inversely with the hinge length and the best responsivity was achieved on the sample with the longest hinge. The corresponding detectivity and response time were respectively 9 × 108 cmHz^1/2/W and 8 ms approximately.

The surface plasmon resonance (SPR) between metal and dielectric material has a good enhancement on electromagnetic wave transmission. In this paper, a series of two-dimension (2D) metal gratings and spiral structures with different geometrical size were experimentally tested by Terahertz time-domain spectroscopy (THz-TDS). The experiment results show that the 2D metal gratings have almost 70% increment on terahertz transmission than the pure silicon substrate in the range of 0.2-2.5THz, which indicates a strong coupling in the terahertz range, and the resonance mode shows a blue shift. On the other hand, the influence of different radiation directions was analyzed. It presents that the slightly higher transmission can be achieved when terahertz wave radiate from the front side than the back side. It reveals that surface plasmon resonance can enhance the terahertz transmission efficiently and has potential applications in security imaging, biological analysis and spectroscopy.