MEMS Components Research Articles

РОЗРОБЛЕННЯ БАЗОВИХ МОДЕЛЕЙ ЄМНІСНИХ АКСЕЛЕРОМЕТРІВ МОВОЮ VHDL-AMS ДЛЯ СХЕМОТЕХНІЧНОГО РІВНЯ АВТОМАТИЗОВАНОГО ПРОЕКТУВАННЯ

In the article, the basic VHDL-AMS models of MEMS-based capacitive accelerometers were developed. The models were designed for two basic types of capacitive accelerometers, namely lamellar and counter-pivotal. The developed models allow us to determine the source of electrical capacitive accelerometers depending on the incoming mechanical and structural parameters and were constructed for MEMS CAD at the circuit level. The circuit level of MEMS development requires an analysis of the total integrated device electric circuits. For this purpose, all the MEMS components should be written in the specific software systems, which would be understandable for the software system. Taking into account that MEMS devices operate on different physical principles, certain difficulties may arise during the electrical analysis, that is, the work of mechanical or other devices need to be described with the help of electric parameters. In the general case, the method for building the VHDL-AMS model of the MEMS-based capacitive accelerometer is needed construction of the simplified mechanical model, and then a simplified electrical model. On the basis of the simplified models, the VHDL-AMS model of electromechanical MEMS devices has been developed. In the article, the method of automated synthesis and mathematical models using the VHDL-AMS language, which is based on the method of electrical analogies were described. They use systems of ordinary differential equations and partial differential equations to determine the relationships between input and output parameters. The sequence and quantity of used differential equations are determined by the physical principles of operation of the MEMS element and the number of energy transformations, which allows increasing the level of automation of synthesis operations compared to existing methods. The results of the basic lamellar and counter-pivotal capacitive accelerometers are also shown. This enables to conduct research and analysis of its parameters and investigate the output electric parameters dependence on the input mechanical ones.

UV-LIGA Based Discrete Fabrication Process for Terahertz Corrugated Feed Horn

Corrugated horn is a kind of key feed component of antenna system, which could be fabricated by electroforming method. However, the feed horn is becoming more difficult to electroform with the increase of frequency. In the terahertz band, which is now of great interest in military and social safety application, the widths of the corrugation teeth and gaps decrease to the micrometer scale, and their depth-width ratios are higher than 2:1. It is really a challenging, time-consuming work to directly machine a terahertz feed horn or make a metal mandrel for electroforming of that.To solve the difficulties in the normal process of terahertz feed horn, a novel discrete fabrication method based on UV-LIGA technology is put forward avoiding the need of mandrel machining. In this method, the manufacturing of a 3D corrugated horn is transformed into 2D slices forming, that is, the corrugation structure is separated into discrete slices according to the width of each tooth or gap. The slices are formed through UV-LIGA technology, in which electroforming is an essential process. Consequently, slices with micro hardness higher than 250HV(200g) and internal compress stress less than 20MPa were electroformed. After assembly and vacuum bonding of slices, typical nickel micro-structure of a conical corrugated horn operating at frequency 2.5THz was fabricated successfully. This layer-by-layer method breaks though the traditional solution of direct machining of metal feed horn or its mandrel by coupling UV-LIGA and vacuum hot bonding technology, which is feasible for vacuum electronic devices like rectangular folded waveguide and multilayer MEMS components moreover.

Formation and homogenization of Si interconnects by non-equilibrium self-propagating exothermic reaction

Si chips have been interconnected by the self-propagating exothermic reactions using Al–Ni NanoFoil and Au80Sn20 solder layers. The instantaneous localized heat across the entire solder presents great potential for the integration of MEMS and optoelectronic components requiring minimal thermal effects. However, the extremely rapid heating and cooling (105−7 °C/s) in the reaction can cause non-equilibrium interfacial reactions and metastable solidification in the transient bonding region. Segregations and metastable phases different from equilibrium ones are inevitably formed in the Si interconnects. In this study, numerical predictions on the temperature profile of the bonding process and the microstructural characterizations by in-situ TEM/SEM were carried out to reveal the formation and homogenization of the reactive bonded structures. The convective mass transportation, directional solidification and inverse segregation due to the great perpendicular temperature gradient in the mushy reacting zone are confirmed to cause the formation of nano-sized metastable phases. Significant segregation of high-temperature phases (Au-enriched phases) was observed, likely due to the convective flow and the inverse segregation induced by volume contraction. These non-equilibrium phases can be homogenized towards the equilibrium status in subsequently accelerated aging, which was supported by the evident inter-diffusion, intermixing and subsequent growth.

Fabrication, characterization and comparative analysis of mechanical properties of micro features generated by reverse micro EDM

Moderate to high aspect ratio micro features (projected) finds wide application in MEMS components, fuel cells for micro reactors, sensors and actuators, micro optical components etc. Reverse micro electro discharge machining (RMEDM) is one of the extensively used process for fabricating such micro features. The present authors have already developed a technique for generating different shapes and sizes of micro features by suitable modification of tool in RMEDM. Mechanical properties like hardness and elastic modulus of these micro features play a significant role in determining their suitability for various applications. Therefore, the objective of this paper is (a) to generate projected micro features corresponding to tapered blind hole depths of 0.1 mm and 0.3 mm using RMEDM and (b) to determine the effect of tapered blind hole depth on the hardness and elastic modulus of the projected micro features. Hardness and elastic modulus were measured using nano indentation technique. Results indicate that starting from the periphery, both hardness as well as elastic modulus first increase (presence of recast layer) and then decrease (presence of heat affected zone) for projected micro feature corresponding to 0.1 mm hole depth before attaining the properties of the parent material. Due to high amount of debris agglomeration in case of 0.3 mm hole depth, high amount of abnormal discharges occur which do not provide sufficient time for the formation of thermally softened layer as was in the case of micro feature corresponding to 0.1 mm hole depth. Hardness, therefore, is always high starting from recast layer to the HAZ before finally attaining the hardness of the parent material. Debris agglomeration did not have much influence on the elastic modulus and the variation of elastic modulus of the micro feature corresponding to 0.3 mm hole depth remains fairly uniform a compared to the parent material.

Numerical modeling of aerosol deposition process

Aerosol Deposition (AD) method is an emerging coating process for deposition of ceramic particles for industrial applications such as MEMS, fuel cells, optical devices and radio frequency components. In this process, various parameters such as nozzle geometry, powder size and type, pressure inside the deposition chamber, and carrier gas flow rate have significant influence on the in-flight particle behavior before impact, and therefore, on the coating properties. In this study, a two-way coupled Eulerian-Lagrangian model is used to study the effects of gas flow rates and substrate location on the gas flow characteristics, bow shock near the substrate, and more importantly on the particle velocity and trajectory upon impact. The study is carried out with a rectangular sonic nozzle. To validate our simulations, locations of the Mach disks in highly under-expanded free-jet conditions are compared with the theoretical and experimental results in the literature. Two different computational geometries are utilized; a 2D planar and a quarter slice of 3D. It is found that, for the rectangular nozzle, the 3D geometry produces more accurate results and can capture the axis-switching phenomenon. Moreover, it is observed that the gas flow structure as well as the in-flight particle behavior obtained from 2D and 3D geometries are almost identical before the Mach disk. In addition, two different drag expressions are employed and it is shown that the influence of Mach and Knudsen numbers on particle behavior in vacuum condition is significant.

Plasma techniques in the production of customized MEMS‐applications

AbstractMicro electromechanical systems (MEMS) have found their way into many kinds of applications. Especially sensors are daily used by each of us in products like cars and smartphones. The focus of Hahn‐Schickard is the development and the production of highly specialized MEMS products, ones that especially enable small companies the access to MEMS technology. The portfolio includes specific inertial sensors like gyroscopes for navigation and safety, acceleration sensors for crash‐test dummies, microfluidic devices for biological, and medical applications, and so on. All of these devices are manufactured in the institute's cleanroom in volumes ranging from single devices up to hundreds of thousands of chips. In this article, the multitude of application scenarios will be demonstrated by way of diverse MEMS components.

Effects of current density on mechanical properties of electroplated nickel with high speed sulfamate bath

In this work, defect-free and high mechanical strength nickel films are deposited at a high growth rate using a high concentration sulfamate bath for applications in fabrication of MEMS components. Effects of the applied current density on the morphology, average grain size, Vickers hardness, micro-mechanical property, and thickness distribution are studied. The average grain size is refined to a minimum value when the current density is increased from 10 to 20 mA/cm2. The finest grain size obtained is 349.8 nm. The grain refinement effect is a result of the promoted nucleation rate as the applied current density increased. When the current density is beyond 20 mA/cm2, overpotential of the nickel reduction reaction is lowered because of the promoted hydrogen evolution and causes coarsening of the average grain size. The film electroplated at 20 mA/cm2 shows a high growth rate at 0.296 μm/min, the highest Vickers hardness at 371 HV, and the yield stress evaluated by micro-compression test is 1.3 GPa. Relationship between the average grain size and the applied current density follows the Hall-Petch relationship well.

High Strength Electrodeposited Au-Cu Alloys Evaluated by Bending Test toward Movable Micro-Components

Au-Cu alloy micro-cantilevers are fabricated from Au-Cu alloy films electrodeposited at different current density. Bending deformation behaviors of the Au-Cu alloy micro-cantilevers are evaluated for applications as components in MEMS devices. Au-Cu alloy films with smaller grain size and higher copper content are obtained when a higher current density is used. The Au-Cu alloy film electrodeposited at 5 mA/cm2 has the finest average grain size among films prepared in this work, which the grain size is 4.76 nm. Bending test of a micro-cantilever prepared from this film shows a high yield stress at 1826 MPa. The high strength is contributed by synergetic effects of the grain boundary strengthening and the solid solution strengthening mechanisms. The deformation behavior changes from ductile to brittle as the copper content increased. The capability to control the grain size and copper concentration simply by adjusting the current density and the high strength are both advantageous in fabrication of MEMS components.

Reliability assessment and failure mode analysis of MEMS accelerometers for space applications

In the present work, the reliability assessment of capacitive MEMS accelerometers of 3 different suppliers (codenamed A, B, and C) for their use in space applications was performed. The developed reliability assessment testing program addressed specific severities of space missions, such as mechanical shocks and vibrations during take-off and rocket stages separation, high temperature gradients and radiation endurance during in-orbit operation. The main aim of the testing was to evaluate the robustness and reliability limits of MEMS devices by overstressing their specific properties through dedicated tests. Typical failures modes were analyzed and root-causes identified on the devices' subsystem level: MEMS structure, ASIC, interconnecting wires, and package. Overall results of the performed reliability assessment tests and failure mode analyses suggest that the most specific MEMS components, namely the microstructures, do not themselves constitute the failure causes. Following the observations, other components, e.g. interconnects, ASIC or packaging, exhibit lower reliability limits to the specific stresses of the space harsh conditions. Comparative analysis of three accelerometers from various suppliers (designs A, B, and C) suggests the design A (in a hermetic ceramic package) to exhibit the best overall reliability for space-specific application conditions. Design B also shows good robustness. However, its non-hermetic packaging makes it unsuitable for the direct use for space applications in the current state. Utilization of a hermetic package and improvement of the wire-bonding temperature resistance would significantly improve this design. Accelerometers of supplier C (in a hermetic ceramic package) have a trend of occasional “infant mortality” early failures. It is therefore very important to perform burn-in and initial pre-screening for these devices. Another strong weak point for this design is related to a low radiation endurance, which shall be significantly improved.

The influence of the focus position on laser machining and laser micro-structuring monocrystalline diamond surface

Micro-structured surface on diamond is widely used in microelectronics, optical elements, MEMS and NEMS components, ultra-precision machining tools, etc. The efficient micro-structuring of diamond material is still a challenging task. In this article, the influence of the focus position on laser machining and laser micro-structuring monocrystalline diamond surface were researched. At the beginning, the ablation threshold and its incubation effect of monocrystalline diamond were determined and discussed. As the accumulated laser pulses ranged from 40 to 5000, the laser ablation threshold decreased from 1.48 J/cm2 to 0.97 J/cm2. Subsequently, the variation of the ablation width and ablation depth in laser machining were studied. With enough pulse energy, the ablation width mainly depended on the laser propagation attributes while the ablation depth was a complex function of the focus position. Raman analysis was used to detect the variation of the laser machined diamond surface after the laser machining experiments. Graphite formation was discovered on the machined diamond surface and graphitization was enhanced after the defocusing quantity exceeded 45 µm. At last, several micro-structured surfaces were successfully fabricated on diamond surface with the defined micro-structure patterns and structuring ratios just by adjusting the defocusing quantity. The experimental structuring ratio was consistent with the theoretical analysis.

An Empirical Model for Controlling Characteristics of Micro Channel Machined Using Abrasive Assisted Electrochemical Jet Machining

Metallic micro channels provide functions of fluid feed and heat exchange in fields of fuel cell, MEMS component, micro mold and heat exchanger. Abrasive assisted electrochemical jet machining (AECJM) is a hybrid manufacturing technology coupling erosion and corrosion concurrently to remove metals. The AECJM shows a great potential in machining micro channels at metallic surface. From production point of view, it is highly necessary to control the channel characteristics, e.g. width and depth, during the AECJM operation to meet possible specifications from industries. This paper presents an empirical model to predict width and depth of micro channels machined in stainless steel 304 using AECJM with electrolytic solution of NaNO3, abrasives of Al2O3 and DC working voltage. The empirical model was established on a basis of non-linear regression analysis with process variables of working voltage, abrasive concentration, solution concentration, jet pressure, jet scan speed and jet scan passes. Verified results show that the empirical model can predict channel width and depth with a deviation from -6.3% to 4.4% for most cases before process operation. However, the strategies of determining machining parameters are highly important when applying the empirical model to reach a specific machining target.

Experimental Study of Diamond Flying-cutting Capability on Brittle Materials

The utilization of brittle materials is very popular in nowadays industry, such as free-form optics, semiconductor devices and MEMS components among many others. Unfortunately the machining difficulty blocks the further application of brittle materials in the advanced fields. The purpose of this paper is to investigate the machining capability of the diamond fly-cutting operation in grooving of brittle materials. The theoretical analysis of diamond fly-cutting technique was studied firstly. Then an experimental setup was established and the grooving experiment of mono-crystalline silicon, Bk7 glass and ceramics was performed. The results show that the fly-cutting of mono-crystalline silicon can achieve the best surface condition. The machining result of mono-crystalline silicon was also influenced by the feed rates. Better machining surface condition with fewer cracks can be obtained with less feed rates.

Machining of microchannel at SS316 surface using abrasive-assisted electrochemical jet machining

Metallic microchannels are increasingly used in fuel cell, MEMS component, cutter, and micromold due to functions of fluid feed and heat exchange. Abrasive-assisted electrochemical jet machining (AECJM) is a hybrid manufacturing technology coupling erosion and corrosion concurrently to remove metals. It shows a great potential in machining microchannels with complex patterns at metallic surface. The present work explored the feasibility of patterning complex microchannels at SS316 surface using AECJM at a condition of Al2O3 abrasives, NaNO3 solution, and DC potential. A series of microchannels were machined by AECJM to investigate the effects of process conditions on the material removal rate, machining current density, aspect ratio, and surface roughness. The results show that the anodic dissolution dominates material removal in the AECJM of SS316 at present conditions. The material removal rate nonlinearly correlates with machining current density between approximate 3 to 10 A/cm2 due to a nonlinear relationship of current efficiency and current density. It is also shown that the anodic dissolution can be influenced positively or negatively by abrasives impingement due to the synergy of erosion and corrosion. Relatively higher abrasive dose and jet velocity result in a reduction of anodic dissolution and however an increase of abrasive erosion. The experiments of fabricating complex patterns demonstrate that AECJM has a high potential to machine microchannels at SS316 efficiently and economically.

Real-time microscopic 3D shape measurement based on optimized pulse-width-modulation binary fringe projection

In recent years, tremendous progress has been made in 3D measurement techniques, contributing to the realization of faster and more accurate 3D measurement. As a representative of these techniques, fringe projection profilometry (FPP) has become a commonly used method for real-time 3D measurement, such as real-time quality control and online inspection. To date, most related research has been concerned with macroscopic 3D measurement, but microscopic 3D measurement, especially real-time microscopic 3D measurement, is rarely reported. However, microscopic 3D measurement plays an important role in 3D metrology and is indispensable in some applications in measuring micro scale objects like the accurate metrology of MEMS components of the final devices to ensure their proper performance. In this paper, we proposed a method which effectively combines optimized binary structured patterns with a number–theoretical phase unwrapping algorithm to realize real-time microscopic 3D measurement. A slight defocusing of our optimized binary patterns can considerably alleviate the measurement error based on four-step phase-shifting FPP, providing the binary patterns with a comparable performance to ideal sinusoidal patterns. The static measurement accuracy can reach 8 μm, and the experimental results of a vibrating earphone diaphragm reveal that our system can successfully realize real-time 3D measurement of 120 frames per second (FPS) with a measurement range of in lateral and 8 mm in depth.

Effect of Surfactant and Alcohol Additives on Etching Characteristics in Aqueous Potassium Hydroxide Solutions

Anisotropic wet etching is a low cost technique for silicon bulk micromachining to fabricate MEMS components such as cantilevers, diaphragms, etc. It is inevitable for the fabrication of microstructures with slanted sidewalls and to remove underneath material for the realization of freestanding microstructures. Potassium hydroxide (KOH) is a popular etchant as it provides high anisotropy between {100}/{110} and {111} planes. In order to alter the etching characteristics, the effect of various kinds of additives such as isopropyl alcohol (IPA), surfactants (Triton X-100) in pure KOH is studied [1-3]. In this work, we studied the etching characteristics of ternary solutions composed of KOH + Triton X-100 + IPA. The concentration of KOH is varied from 5-40 wt% in step of 5 wt%, while the concentrations of Triton and IPA are kept fixed at 0.1 vol% and 15 vol%, respectively. In the different compositions of ternary solutions, the etch rate and etched surface morphologies of Si{100}, Si{110} and Si{111} are investigated. In addition to that the undercutting at convex corners, which is very important parameter for designing compensation structure to protect convex corner and to estimate etching to release the structure from the substrate, is measured. In order to explore the thermal oxide as mask and structural material, the etch rate of silicon dioxide is also measured. In the ternary solution comprising low concentration KOH, the etching characteristics are more significantly affected by Triton than IPA. However, in the case of ternary solution containing high concentration KOH, IPA influences etching characteristics more prominently than Triton. The systematic study of etch rate, etched surface roughness, and undercutting at convex corners in ternary solution presented in this work is very useful to select the composition of ternary solution for MEMS applications as per the requirement.

Effect of NH2OH on Etching Characteristics of Si{100} in KOH Solution

Potassium hydroxide (KOH) and tetramethylammonium hydroxide (TMAH) are most extensively used etchants for wet anisotropic etching process. Amongst these two etchants, KOH is a low cost etchant and provides high etch rate anisotropy between Si{111} and Si{100} planes. Increasing the etch rate is an important research problem for both academic and industrial applications. In this research, we study the effect of hydroxylamine (NH2OH) in 20 wt% KOH on the etching characteristics of Si{100}. This type of wafer orientation (i.e. Si{100}) is selected owing to its popularity in fabricating planar semiconductor devices (e.g. diode, transistor, complementary metal oxide semiconductor (CMOS), etc.) and MEMS components (e.g. cantilever, diaphragm, etc.). A systematic parametric analysis of various concentrations of hydroxylamine (from 0 to 20% in step of 5%) added 20 wt% KOH is carried out and its effect on the etching characteristics is discussed. We have found that the etch rate of Si{100} is increased threefold when 15% NH2OH is added to 20 wt% KOH solution. Additionally, this concentration also exhibits improved etching characteristics including undercutting rate, etch selectivity, and surface morphology. We have obtained improved etching characteristics when NH2OH is added to 20 wt% KOH. Due to an improvement in etching characteristics, present research is very useful to pave the path toward application in microfabrication industries as well as academic research laboratories.

Experimental Investigation of Photostrictive Materials for MEMS Application

Micro-Electro-Mechanical-Systems (MEMS) is an emerging technology that integrates micromachined mechanical structures with integrated circuits (IC). During the last two decades, it has grown vastly as a prominent research area among scientists and engineers. Usually the main components of MEMS are sensors, actuators, and structures with all in microscale. A photostrictive mate-rial has high potential to be used in a MEMS application to develop an ad-vanced optical actuator. A strain is induced when a photostrictive material is il-luminated by high intensity light, which is known as photostriction. This phe-nomenon can be generally described as the combined effect of the photovoltaic effect and the converge-piezoelectric effect. When an incident light strikes a photostrictive material, a photovoltage is produced and this photovoltage develops strain in the material. Lanthanum modified lead zirconate titanate (Pb, La) (Zr, Ti) O3 ceramic doped with WO3, called PLZT, is one of the photostrictive ceramics which has an advantageous use as a wireless remote control over traditional actuators. Traditional actuators require wire connections to transmit the control signal; these wires yield noise via external electromagnetic fields. Whereas, PLZT actuators can transmit the control signal without wires which can eliminate possible noise due to the external electromagnetic field. In this current research, the photostrictive effect of a thin PLZT film on a silicon wafer is investigated experimentally. The transverse deflection of the PLZT optical actuator cantilever beam has been measured for stationary continuous light as well as for pulses of light using an optical chopper at various light intensities and focused locations. Results indicate that transverse deflection increases with the increase of light intensity. Also, the maximum transverse deflection at the free end of the cantilever beam for stationary light has been found to be three times larger than that for the pulses of light.

Impact of environmental conditions on the reliability of MEMS components from optical applications

The reliability design and the lifetime of MEMS from optical applications is strongly dependent on the operating conditions. In optical devices an additional stress is introduced by the temperature gradient appearing during operation. The thermal stress introduced in the structure modifies the component response and its lifetime. The investigated sample is a micromirror fabricated from gold using the MEMS technologies and tested by an atomic force microscope. The scope is to analyse the temperature and relative humidity influence on the mechanical and tribological behaviours. Using a mechanical force given by the bending deflection and stiffness of the AFM probe, the dependence between the applied force and the micromirror deformation is monitored as a function of temperature. By increasing the temperature of structures the stiffness decreases based on the thermal relaxation of the material. If the relative humidity increases the adhesion between the micromirror and substrate is improved based on the capillarity effect. The results obtained are useful to MEMS designers who can predict the micromirror response as a function of the operating conditions with influence on the actuation energy, the accuracy in response and the system lifetime.

Formation and characterization of microcantilevers produced from ionic liquid by electron beam irradiation

Abstract Recently, ionic liquids (ILs) have been recognized to have significant potential as precursors or reaction media in nanolithography and MEMS component technologies. In this work, we demonstrate straightforward fabrication of positioned and well-defined microscale structures by electron beam (e-beam) irradiation of two different ILs: 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (HMIM TFSI) and 1-(6-hydroxyhexyl)-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (HMIM-OH TFSI). The study includes comparison between the compositions and mechanical properties of corresponding e-beam-irradiated ILs. The average Young's moduli of prepared IL microcantilevers measured in beam bending tests were found to be 7.2 ± 0.9 GPa and 3.5 ± 1.3 GPa for HMIM-OH TFSI and HMIM TFSI, respectively. Infrared spectroscopy indicated the formation of polymer in e-beam-irradiated HMIM-OH TFSI, while structures from HMIM TFSI melted in ambient conditions. The presented results showcase the potential IL precursors in microscopic 3-D printing approaches for mechanical elements in MEMS technologies as well as for developing reversibly solidified precursors for lithography.

Nanocharacterization of the adhesion effect and bending stiffness in optical MEMS

The scope of this paper is the reliability design and testing of flexible MEMS components as clamp-clamp beams for the out-of-plane displacement. The field of implementation of such structures is in optical relevant applications such as the optical microsensors or optical microswitches. Moreover these structures can be successfully implemented in RF switches or in the other MEMS applications. The research studies presented in this paper consider the analytical and numerical analysis follow by the experimental validation. The mechanical and tribological characteristics such as the sample static response under an applied force and the adhesion effect between the flexible structure and substrate are investigated. The samples under test are fabricated from a reflective material – gold. Experimental investigations are performed by atomic force microscopy in order to determine the response of the gold microbridges under an applied force. Moreover, to identify the proper geometry that is less sensitive to a thermal gradient, different geometrical configurations of microbridges are tested under different temperatures. An etalon structure is considered as a reference beam and it is compared with the other samples fabricated in the same geometrical dimensions but with some additional rectangular holes performed on the flexible plate. The scope of holes is to reduce the temperature influence on the mechanical behaviour of clamp-clamp beam from application where a thermal gradient occurs. During numerical analysis and experimental investigations, the temperature of samples is increased from 20°C to 100°C and the sample response is monitored. A comparison between numerical and experimental results is provided at the end of paper. The research results are useful for designers to predict the behaviour of material and structure from optical or thermal applications in order to improve the reliability and the MEMS lifetime.