Showing papers in "Sensors and Actuators A-physical in 1998"
TL;DR: Electrostrictive polymer (EP) dielectric actuators have been shown to produce 5 to 20 times the effective actuation pressure of conventional air-gap electrostatics at the same electric field strength as mentioned in this paper.
Abstract: The electrostriction of elastomeric polymer dielectrics with compliant electrodes is potentially useful as a small-scale, solid-state actuator technology. Electrostrictive polymer (EP) materials are capable of efficient and fast response with high strains (> 30%), good actuation pressures (up to 1.9 MPa), and high specific energy densities (up to 0.1 J g−1). In this article, the mechanism of electrostriction is shown to be due to the electrostatic attraction of free charges on the electrodes. Although EP actuators are electrostatics based, they are shown to produce 5–20 times the effective actuation pressure of conventional air-gap electrostatics at the same electric field strength. The thin uniform dielectric films necessary for fabrication of EP actuators have been fabricated by techniques such as spin coating, casting, and dipping. A variety of materials and techniques have been used to produce the compliant electrodes, including lift-off stenciling techniques for powdered graphite, selective wetting of ionically conductive polymers, and spray coating of carbon blacks and fibrils in polymeric binders. Prototype actuators have been demonstrated in a variety of configurations such as stretched films, stacks, rolls, tubes, and unimorphs. Potential applications of the technology in areas such as microrobots, sound generators, and displays are discussed in this article.
1,436 citations
TL;DR: The IBM SU-8 resist as discussed by the authors is an epoxy-based resist designed specifically for ultrathick, high-aspect-ratio MEMS-type applications and it has been shown that with single-layer coatings, thicknesses of more than 500 μm can be achieved reproducibly.
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.
613 citations
TL;DR: In this article, the surface charge accumulation on the electrode passivation of silicon cantilever actuators has been observed, and charge decay characteristics were recorded for a silicon oxide passivation and a multilayer passivation by silicon oxide and silicon nitride.
Abstract: Silicon dioxide and silicon nitride coatings are preferably used as dielectric layers for short-circuit protection in capacitive silicon microsensors and microactuators. However, their tendency to electrostatic charging can diminish the device reliability. Gas discharges in the air gap of silicon cantilever actuators have been observed, resulting in surface charge accumulation on the electrode passivation of the devices. Charge decay characteristics were recorded for a silicon oxide passivation and a multilayer passivation by silicon oxide and silicon nitride. The charges are found to be highly stable in time. Based on these observations, rules for the application and design of dielectric layers in microdevices are proposed.
315 citations
TL;DR: In this article, the orientation dependence in chemical anisotropic etching of single-crystal silicon was evaluated for a wide range of etching conditions, including KOH concentrations of 30 to 50% and temperatures of 40 to 90 °C.
Abstract: We have evaluated the orientation dependence in chemical anisotropic etching of single-crystal silicon. Etch rates for a number of crystallographic orientations have been measured for a wide range of etching conditions, including KOH concentrations of 30 to 50% and temperatures of 40 to 90 °C. Though the etchants all consist of the same components KOH and water, the orientation dependence varies considerably with change in etchant temperature and concentration. The resulting etch-rate database allows numerical prediction of etch profiles of silicon, necessary for the process design of microstructures. Changing the KOH concentration yields different etch profiles both analytically and experimentally.
304 citations
TL;DR: In this paper, a theoretical treatment to model the snap-through of a double-clamped beam is given, starting from a classical theory for "slender beams" the model is extended to also take compression into account.
Abstract: A theoretical treatment to model the snap-through of a double-clamped beam is given. Starting from a classical theory for ‘slender beams’ the model is extended to also take compression into account. This significantly changes the predicted snap-through path, and may also change the snapping mechanism to a different regime where the maximum force is set by compression rather than the Euler instability. It is also shown that the model can be used for a class of non-homogeneous sandwich beams such as those micromachined in our referred experiment.
221 citations
TL;DR: In this paper, a calibration procedure for triaxial accelerometers is proposed, which uses the fact that the modulus of the acceleration vector measured with a triaxis accelerometer equals 1g under quasi-static conditions.
Abstract: In the medical field triaxial accelerometers are used for the monitoring of movements. Unfortunately, the long-term use of accelerometers is limited by drift of the sensitivities and the offsets. Therefore, a calibration procedure is designed which allows in-use calibration of a triaxial accelerometer. This procedure uses the fact that the modulus of the acceleration vector measured with a triaxial accelerometer equals 1g under quasi-static conditions. The calibration procedure requires no explicit knowledge of the actual orientation of the triaxial accelerometer with respect to gravity and requires only quasi-static random movements. The procedure can be performed within several minutes. Considering practical applications, it is found possible to obtain an average error smaller than 3% (of 1 [g]) with the calibration procedure for inputs caused by ‘standing straight and moving slightly’ when the offsets only are estimated. For the input caused by the sequence that occurs when going to bed, it is found possible to obtain errors smaller than 3% for estimating all parameters.
208 citations
TL;DR: In this paper, a simple and inexpensive method for evaluating the transverse piezoelectric coefficient (d 31 ) of PZT thin films is described. The technique is based upon the flexure of a coated substrate, which imparts an ac two-dimensional stress to the PZE. The surface charge generated via the mechanical loading is converted to a voltage by an active integrator.
Abstract: This paper describes a simple and inexpensive method for evaluating the transverse piezoelectric coefficient ( d 31 ) of piezoelectric thin films. The technique is based upon the flexure of a coated substrate which imparts an ac two-dimensional stress to the piezoelectric film. The surface charge generated via the mechanical loading is converted to a voltage by an active integrator. Plate theory and elastic stress analyses are used to calculate the principal stresses applied to the film. The d 31 coefficient can then be determined from knowledge of the electric charge produced and the calculated mechanical stress. For 52/48 sol-gel lead zirconate titanate (PZT) thin films, the d 31 coefficient was found to range from − 5 to − 59 pC/N and is dependent on poling field.
191 citations
TL;DR: In this article, a thin-film/silicon micromachined hybrid actuator is described, which relies on the flexure of a screen printed PZT layer on a silicon membrane (8 mm × 4 mm × 70 μm).
Abstract: A new silicon-based micropump is described in this paper. The key element of the device is a thick-film/silicon micromachined hybrid actuator. The actuation principle relies on the flexure of a screen printed piezoelectric lead zirconate titanate (PZT) layer on a silicon membrane (8 mm × 4 mm × 70 μm). An investigation into the deposition technology of the bottom electrode for the piezoelectric material showed that a gold resinate or Pt evaporated electrode on a 500 nm thick SiO 2 covered silicon wafer achieved best results for the membrane actuator. Inlet and outlet valves are of the cantilever type and use deep boron diffusion together with KOH etching. Pump rates of up to 120 μl min −1 have been achieved. A maximum backpressure of 2 kPa was measured when using a 600 V pp sinusoidal drive voltage at 200 Hz across a 100 μm thick PZT layer. The pump was compared with a conventional surface mounted piezoelectric driven micropump. The conventional pump achieves a performance which was a factor of 3–6 more efficient, but does not allow mass production.
174 citations
TL;DR: In this paper, a special thermal design of the chambers, combined with thin film platinum resistors as temperature sensors and heaters, was proposed for rapid temperature cycling and control at low power.
Abstract: Microchambers have been fabricated in silicon by bulk micromachining using anisotropic wet etching. Rapid temperature cycling and control at low power is achieved using a special thermal design of the chambers, combined with thin film platinum resistors as temperature sensors and heaters. The chambers have been used for the polymerase chain reaction (PCR) in order to amplify DNA. Rapid temperature cycling and small size are promising attributes for portable high efficiency analytical systems.
165 citations
TL;DR: In this paper, the authors presented two advanced thin-film sensor technologies: strain gauges and thermocouples, which are sputter deposited directly onto the test articles and are only a few micrometers thick; the surface of the test article is not structurally altered and there is minimal disturbance of the gas flow over the surface.
Abstract: Advanced thin-film sensor techniques that can provide accurate surface strain and temperature measurements are being developed at NASA Lewis Research Center. These sensors are needed to provide minimally intrusive characterization of advanced materials (such as ceramics and composites) and structures (such as components for Space Shuttle main engine, high-speed civil transport, and general aviation aircraft) in hostile, high-temperature environments, and for validation of design codes. This paper presents two advanced thin-film sensor technologies: strain gauges and thermocouples. These sensors are sputter deposited directly onto the test articles and are only a few micrometers thick; the surface of the test article is not structurally altered and there is minimal disturbance of the gas flow over the surface. The strain gauges are palladium-13% chromium based and the thermocouples are platinum-13% rhodium versus platinum. The fabrication techniques of these thin-film sensors in a class 1000 cleanroom at the NASA Lewis Research Center are described. Their demonstration on a variety of engine materials, including superalloys, ceramics, and advanced ceramic matrix composites, in several hostile, high-temperature test environments is discussed.
156 citations
TL;DR: In this paper, a coherent empiro-theoretical approach to the flow behavior of micro diffuser channels is tried, mainly based on general investigations of energy conversion and experimental data from classical hydraulics.
Abstract: A coherent empiro-theoretical approach to the flow behavior of micro diffuser channels is tried. Microdiffusers may be advantageously employed as dynamic passive valves in micropumps. The central number of merit is the rectification efficiency e which expresses the flow directing performance of a passive valve. It mainly depends on the aperture angle, relative channel length, throat rounding, flow velocity, and frequency. The highest ¦ e ¦ -value possible is around 0.25…0.4. The approach is mainly based on general investigations of energy conversion and experimental data from classical hydraulics. The derivations are compared with test results of different authors.
TL;DR: In this paper, the authors report an effective way of measuring the viscosity of liquids by using a microacoustic Love-wave device and present experimental results together with a suitable electronic sensor set-up.
Abstract: In this contribution we report an effective way of measuring the viscosity of liquids by using a microacoustic Love-wave device. Lovewave devices provide one of the highest sensitivities among microacoustic devices and they are moreover well suited for liquid-sensing applications. We discuss the possibility of viscosity sensing with Love-wave devices using the viscosity-induced damping and velocity change of the wave. We present experimental results together with a suitable electronic sensor set-up which also allows us to determine whether the test liquid is actually measured in the Newtonian range.
TL;DR: In this article, criteria for the minimum compression ratio of a micropump are derived depending on the medium transported and the surface and interfacial energies of the liquid have to be taken into account.
Abstract: Due to the small stroke of micro actuators, the compression ratio of micropumps is frequently small. This means that serious constraints exist for most micropump designs concerning self-priming capability and bubble tolerance. To access this problem in this study, criteria for the minimum compression ratio of a micropump are derived depending on the medium transported. It turns out that under real operation and handling conditions (outgassing, incomplete priming) design rules applicable for gas pumps also have to be used for liquid pumps. Next, if the liquid pump is to be able to prime itself, a critical pressure has to be achieved, which leads to a further increase of the necessary compression ratio. To determine this critical pressure, the surface and interfacial energies of the liquid have to be taken into account.
TL;DR: In this paper, an analysis of the performance of a single chamber and a double chamber piezoelectric valve-less pumps is presented, where the authors show that a series connection usually is advantageous to a parallel connection even for the purpose of increasing the flow rate.
Abstract: An analysis of the performance of a single chamber and a double chamber piezoelectric valve-less pumps is presented. The analysis will enhance the proper design of such pumps. Also presented is an analysis of the different combination modes possible for the operation of such pumps such as a series connection and a parallel connection. It is shown, that a series connection usually is advantageous to a parallel connection even for the purpose of increasing the flow rate (for fixed pressure difference). reserved.
TL;DR: In this paper, the authors presented the study of new stacked thin membranes (SiO 2 /SiN 1.2 ) supporting the heating element (polysilicon resistor) for thin-film microheaters for decreasing power consumption in portable applications.
Abstract: There is considerable interest in thin-film microheaters for decreasing the power consumption in portable applications. In this paper, we present the study of new stacked thin membranes (SiO 2 /SiN 1.2 ) supporting the heating element (polysilicon resistor). The great interest of using SiN 1.2 deposited onto a SiO 2 layer is the improvement in mechanical properties of the membrane, leading to a fabrication yield very close to 100%. Microheaters fabricated with a 1.6 mm × 1.6 mm square and 0.7 μm thick SiO 2 /SiN 1.2 membrane give promising results in terms of power consumption; 230°C is reached with an electrical power of 50 mW.
TL;DR: In this paper, the principle of displacement eddy current sensors and highlights the advantages compared with other non-contact sensors are presented, key factors that influence the sensor accuracy are presented and some initial results are presented to demonstrate the efficiency of the methods.
Abstract: This paper reports the principle of displacement eddy current sensors and highlights the advantages compared with other non-contact sensors. Key factors that influence the sensor accuracy are presented. An experimental study has been undertaken into the effects of different target metals measured by the sensors. Based on a theoretical analysis, the methods to overcome the inhomogeneity (electrical run out) of eddy current sensors are discussed. Some initial results are presented to demonstrate the efficiency of the methods.
TL;DR: In this paper, the relationship between nozzle/diffuser flow coefficients and the performance of the valveless pumps with different Reynolds number ranges and conical angles is investigated. And the authors also proposed a flow model of the Valveless pump with a silicon micro-valveless wafer.
Abstract: The nozzle/diffuser flow with different Reynolds number ranges and conical angles is analyzed first. It is found that the flow coefficients of nozzle/diffuser ξn and ξd vary with angle with different trends for large (> 105) and small (<50) Reynolds number ranges. The flow model of valveless pumps with nozzle/diffusers is proposed, and the relationship between nozzle/diffuser flow coefficients and the performance of the valveless pumps is investigated. In experiments, silicon nozzle/diffuser elements with conical angles of 5°, 7.5° and 10° and a silicon micro valveless pump wafer are fabricated. The experimental ξd, ξn, and ξn/ξd decrease with increasing nozzle/diffuser angles in the Re range ( 2000) of the experiment. The pumping direction of the fabricated valveless pump agrees with the nozzle/diffuser flow experiments and analysis. The pump works successfully with the output flow rate of 28 μl/min under the input power of 50 mW and 500 Hz.
TL;DR: In this article, a continuous spinning current vector is generated in the device by spatially superimposing two periodic biasing currents, and the resulting voltages allow the constant Hall voltage to be separated from the periodic offset voltage.
Abstract: A novel method for dynamic offset compensation in a Hall plate is presented. The continuous spinning current method is based on minimalsize four-contact Hall devices and, therefore, the lowest possible offset resulting from material inhomogeneities is achieved. A continuous spinning current vector is generated in the device by spatially superimposing two periodic biasing currents. The resulting voltages allow the constant Hall voltage to be separated from the periodic offset voltage. Remaining offsets are below 10 μT, which corresponds to fractions of the earth's magnetic field.
TL;DR: In this article, a tensile testing of single-crystal silicon film was carried out on a silicon chip and the results were compared with those of bulk materials, such as elastic modulus and fracture strain.
Abstract: Uniaxial tensile testing of single-crystal silicon film was carried out on a silicon chip. A tensile testing system was integrated on a silicon chip. A process for fabricating a test chip containing a specimen whose tensile axis has an arbitrary orientation was developed. The mechanical properties, such as elastic modulus and fracture strain, of silicon films having different orientations of 〈100〉, (110), and 〈111〉, are measured. The results are compared with those of bulk materials.
TL;DR: In this paper, the authors compared five different procedures commonly used to rinse and dry released microstructures: evaporation drying with deionized (DI) water or methanol, sublimation drying with t-butyl alcohol orp-dichlorobenzene, and supercritical drying with COz.
Abstract: Five different procedures commonly used to rinse and dry released microstructures are compared: evaporation drying with deionized (DI) water or methanol, sublimation drying with t-butyl alcohol orp-dichlorobenzene, and supercritical drying with COz. For objectivecomparison, identical test structures, made by the MCNC Multi-User EMS Processes (MUMPS), are used in evaluating the drying techniques. The test chips contain arrays of surface-micromachined polysilicon cantilevers (2 km thick, 2 pm gap from the substrate) with varying widths and lengths. Some beams feature dimples or tips to quantify their anti-stiction effect. This study reveals, for the first time, that the maximum beam length obtainable increases as the beam width increases for the cases of sublimation and supercritical dryin,, 0 opposite to the previously known case of evaporation drying. Both sublimation drying methods as well as supercritical drying rendered good results, releasing cantilevers up to 700 km in length without stiction. We also introduce a new setup that considerably improves the way sublimation is used to dry microstructures. 0 1998 Elsevier Science S.A.
TL;DR: In this paper, a thorough analysis of the static and dynamic behavior of bulk-micromachined silicon accelerometers is given, where analytical techniques are used to provide insight into trends and give results within 1% of numerical simulations performed in ANSYS.
Abstract: In this paper a thorough analysis of the static and dynamic behavior of bulk-micromachined silicon accelerometers is given. Analytical techniques are used and it will be shown that these provide insight into trends and give results within 1% of numerical simulations performed in ANSYS. Discussed issues include the static modeling (sensitivity, cross-axis sensitivity) of the two most commonly used structures, i.e., cantilever-supported and multiple-supported structures, and also the dynamic behavior of these devices, such as resonance and damping.
TL;DR: In this paper, the electromechanical displacement properties of two recently developed piezoelectric actuators, referred to as RAINBOW and THUNDER, have been measured and compared.
Abstract: The electromechanical displacement properties of two recently developed piezoelectric actuators, referred to as RAINBOW and THUNDER, have been measured and compared. The actuators evaluated in this investigation are fabricated from 2.54 cm diameter PZT-5H and PZT-5A piezoelectric ceramic disks and are produced with the same total device thicknesses and ceramic-to-metal thickness ratios. For the compositions tested, the RAINBOW devices are found to exhibit 10–25% greater free-displacement properties than comparable THUNDER devices. This finding indicates that larger internal stresses are developed during the RAINBOW process, which lead to enhanced amplification of axial displacement.
TL;DR: In this article, 6H-SiC piezoresistive pressure sensors have been batch fabricated and tested up to 500 °C in atmosphere, and the full-scale outputs of a typical sensor are 40.66 and 20.03 mV at 23 and 500 mV, respectively.
Abstract: 6H-SiC piezoresistive pressure sensors have been batch fabricated and tested up to 500 °C in atmosphere. At 1000 psi, the full-scale outputs of a typical sensor are 40.66 and 20.03 mV at 23 and 500 °C, respectively. The full-scale linearity of − 0.17% and hysteresis of 0.17% compare favorably with current silicon technology. No significant degradation in the performance characteristics is observed when the sensors are operated for 10 h at 500 °C. The temperature coefficient of gage factor (TCGF) exhibits negative values of − 0.19 and − 0.11%/ °C at 100 and 500 °C, respectively. Excellent control of the diaphragm thickness is the result of a stabilized electrochemical etching process. The micromachining of bulk 6H-SiC eliminates the thermal-mismatch problem inherent in micromachined heterostructures. This work demonstrates batch manufacture and operation of 6H-SiC pressure sensors for temperatures beyond those of conventional silicon technology.
TL;DR: In this paper, a low-field sensor based on buried silicon Hall devices, combining two vertical Hall devices for the planar sensitivity and novel horizontal Hall elements for the orthogonal sensitivity, is presented.
Abstract: A ± 0.3 ° precision in angular-position measurement over a 360 ° rotation has been obtained with a novel fully integrated 3-D magnetic sensor. This low-field sensor, based on buried silicon Hall devices, combines two vertical Hall devices for the planar sensitivity and novel horizontal Hall elements for the orthogonal sensitivity. The advantages of this sensor are its very low cross-sensitivity and its remarkably high long-term stability. The X and Y directions are used as high-precision angular-position measurements and the third direction helps to compensate for mechanical misalignment.
TL;DR: In this article, an analytical method based upon a Green's function solution to the linearized Reynolds equation is presented which allows the resulting forces from compressible squeeze film damping to be rapidly calculated for arbitrary acoustic venting conditions along the edges of a moveable structure.
Abstract: An analytical method based upon a Green's function solution to the linearized Reynolds equation is presented which allows the resulting forces from compressible squeeze film damping to be rapidly calculated for arbitrary acoustic venting conditions along the edges of a moveable structure. The resulting models are computationally compact, and thus applicable for dynamic system simulation purposes. Arbitrary deflection profiles can also be treated, enabling the calculation of damping effects for cantilevers, diaphragms, tilting plates, and drum-head modes. The method is theoretically described and a catalog of several useful cases is then presented to illustrate its use.
TL;DR: In this article, a micro ion drag pump with planar electrodes on a glass substrate is fabricated and tested, and the pump consists of a planar electrode pair array driven by DC voltage using unipolar conduction.
Abstract: A micro ion drag pump with planar electrodes on a glass substrate is fabricated and tested. The pump consists of a planar electrode pair array driven by DC voltage using unipolar conduction. Ethyl alcohol is pumped in both directions, and the flow rate and the pressure are measured in channels of depth 100 μm or 200 μm and width fixed at 3 mm. It is found that the pump can be fabricated easily and at a lower cost than the micro ion drag pumps previously investigated.
TL;DR: In this article, a mathematical model for the effective viscosity of a gas film in small air gaps between silicon and metal surfaces is presented based on the solution of the linearized Boltzmann equation assuming both symmetric and non-symmetric molecular interaction between gas-silicon and gas-metal interfaces.
Abstract: A mathematical model for the effective viscosity of a gas film in small air gaps between silicon and metal surfaces is presented. The model is based on the solution of the linearized Boltzmann equation assuming both symmetric and non-symmetric molecular interaction between gas-silicon and gas-metal interfaces. The equation is solved with variational and numerical methods, and a simple approximate equation for the effective viscosity is given to be used in practical design. It is valid in viscous, transitional and molecular damping regions and it is used together with the linearized Reynolds equation to build a simulation model for the squeezed-film damping in a micromachined capacitive accelerometer. The tangential momentum accommodation coefficient for the single-crystal silicon surface is extracted by comparing accelerometer frequency response measurements and the mathematical model in the transitional and molecular damping regions.
TL;DR: In this paper, low-temperature bonding of Si and SiO 2 by the surface activation method in vacuum has been investigated and shown to be twice as strong as conventional bonding before annealing.
Abstract: We have investigated low-temperature bonding of Si and SiO 2 by the surface activation method in vacuum. In the method, Ar beam etching is used to create a clean surface which has strong bonding ability. The specimens are bonded in the vacuum without exposing them to the atmosphere. The strength of Si/Si bonding prepared at room temperature by the method is equivalent to the bulk strength. SiO 2 /SiO 2 bonding by the method is twice as strong as conventional bonding before annealing. In addition, the bonding prepared by Ar beam is stronger than that prepared by reactive molecule beam etching such as H 2 O and NH 3 . The influence of surface oxidation was examined by exposing an etched Si surface to residual gas in the vacuum chamber. Adsorption of reactive molecules such as H 2 O on the etched surface causes reduction of bonding strength, whereas Ar gas does not affect the bonding. These results mean that a clean surface etched by Ar beam has strong bonding ability even at room temperature.
TL;DR: In this paper, the first fabrication of surface-micromachined microbolometers made of polycrystalline silicon-germanium alloy (poly Si 0.7 Ge 0.3 ).
Abstract: This paper reports the first fabrication of surface-micromachined microbolometers made of polycrystalline silicon-germanium alloy (poly Si 0.7 Ge 0.3 ). The electrical and mechanical properties of this material have been measured and the effects of the deposition conditions and annealing temperature on them have also been investigated. The complete process for the bolometer fabrication is presented and the possibility of reducing the process temperature to 650 °C is demonstrated. The thermal behaviour of the device is fully analysed and it is demonstrated that the use of poly Si 0.7 Ge 0.3 instead of polycrystalline Si (poly Si) decreases the thermal conductance of the device (values lower than 10 −6 W K −1 are obtained). Preliminary measurements give a value of 10 4 V W −1 for the IR responsivity.
TL;DR: In this paper, the authors developed a fabrication technology for realization of three-dimensional microstmctures composed of different materials using excimer laser ablation and ultrafine particle (UFP) jet molding.
Abstract: We have developed a fabrication technology for realization of three-dimensional microstmctures composed of different materials using excimer laser ablation and ultrafine particle (UFP) jet molding. We have named this technology the jet molding system (JMS). This method enables the production of three-dimensional microdevices composed of actuator, sensor materials (PZT), and electrodes (metal). Insertmolding and mask-deposition methods were applied to obtain these structures. SEM observation as well as density and electrical property measurements showed good pattern transfer fidelity with sufficient deposited layer quality (density of better than 85%, dielectric constant of deposited PZT layer of 760). The deposition rate of PZT was much faster than that obtained using any other deposition technique, and a PZT layer up to 40 μm of thick was formed with the desired metal electrode structure.