MEMS Fabrication on LTCC Substrates for RF Applications: Challenges and Perspectives

2016 ◽  
Vol 2016 (CICMT) ◽  
pp. 000089-000094
Author(s):  
Dorra Bahloul ◽  
Achraf Ben Amar ◽  
Ammar B. Kouki
Keyword(s):  
Microelectromechanical Systems ◽  
Mems Devices ◽  
Surface Polishing ◽  
Mems Fabrication ◽  
Successful Solution ◽  
Radar Applications ◽  
Pre Treatment ◽  
Final Surface Finish ◽  
Mems Process ◽  
Mechanical Surface

Abstract Microelectromechanical Systems (MEMS) are often used in transceiver modules, especially for telecommunication and radar applications. In this paper, we present recent progress in the development on a MEMS-on-LTCC process. We focus on the Low Temperature Co-fired Ceramic (LTCC) substrate issues and we present a successful solution for overcoming the substrate challenges through surface pre-treatment using a chemical mechanical surface polishing (CMP) process which allows us to reach the required smoothness for the fabrication of MEMS devices. We discuss various process parameters such as slurry type, rotating pad and rotation speed, and show their impact on the final surface finish. With an optimized process, the maximum roughness was decreased from more than 10μm to less than 0.5 μm over a 640 × 640 μm2 LTCC sample. Also, we present the various MEMS process steps starting with the deposition and patterning of various layers to a prototype switch highlighting the validated steps and the challenges encountered. A brief discussion of the perspectives for the integration of MEMS and LTCC technologies is also presented.

scholarly journals MEMS' Rocky Road

2002 ◽  
Vol 124 (06) ◽  
pp. 38-41 ◽  
Author(s):  
John DeGaspari
Keyword(s):  
Microelectromechanical Systems ◽  
Pressure Sensors ◽  
Trade Association ◽  
Absolute Pressure ◽  
Mems Devices ◽  
Hard Drives ◽  
Industry Group ◽  
Group A ◽  
Potential Demand ◽  
Mems Process

This article highlights that there is potential demand for microelectromechanical systems (MEMS) devices across a range of industries. In 2002, the five leading applications of MEMS will use 21.5 million disposable blood pressure sensors, 28.7 million manifold absolute pressure sensors for engines, 85 million packaged airbag accelerometers, 425 million inkjet printer heads, and a whopping 1.58 billion read/write magnetic heads for computer hard drives. In MEMS, process is driven by design, so it is important for companies seeking to commercialize a micro device to evaluate the capabilities of a foundry. Industry groups are starting to recognize standardization as an issue, and are focusing on fabrication. The MEMS Industry Group, a trade association based in Pittsburgh, identified standardization as a key challenge in its 2001 annual report. The Group plans to issue a report on foundries and fabrication sooner.

scholarly journals Cavity-BOX SOI: Advanced Silicon Substrate with Pre-Patterned BOX for Monolithic MEMS Fabrication

Micromachines ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 414
Author(s):  
Marta Maria Kluba ◽  
Jian Li ◽  
Katja Parkkinen ◽  
Marcus Louwerse ◽  
Jaap Snijder ◽  
...  
Keyword(s):  
Complex Geometry ◽  
Pressure Sensors ◽  
Silicon On Insulator ◽  
Test Case ◽  
Mems Devices ◽  
Device Layer ◽  
Mems Fabrication ◽  
Silicon Islands ◽  
Design Freedom ◽  
Deep Brain

Several Silicon on Insulator (SOI) wafer manufacturers are now offering products with customer-defined cavities etched in the handle wafer, which significantly simplifies the fabrication of MEMS devices such as pressure sensors. This paper presents a novel cavity buried oxide (BOX) SOI substrate (cavity-BOX) that contains a patterned BOX layer. The patterned BOX can form a buried microchannels network, or serve as a stop layer and a buried hard-etch mask, to accurately pattern the device layer while etching it from the backside of the wafer using the cleanroom microfabrication compatible tools and methods. The use of the cavity-BOX as a buried hard-etch mask is demonstrated by applying it for the fabrication of a deep brain stimulation (DBS) demonstrator. The demonstrator consists of a large flexible area and precisely defined 80 µm-thick silicon islands wrapped into a 1.4 mm diameter cylinder. With cavity-BOX, the process of thinning and separating the silicon islands was largely simplified and became more robust. This test case illustrates how cavity-BOX wafers can advance the fabrication of various MEMS devices, especially those with complex geometry and added functionality, by enabling more design freedom and easing the optimization of the fabrication process.

Microsensors, MEMS and NEMS Based Complex Adaptive Smart Devices and Systems

2001 ◽  
Author(s):  
Vijay K. Varadan
Keyword(s):  
Self Assembly ◽  
Communication Systems ◽  
Microelectromechanical Systems ◽  
System Level ◽  
Smart Devices ◽  
Mems Devices ◽  
Wafer Level ◽  
Sensors And Actuators ◽  
Complex Adaptive ◽  
Microelectronics Industry

Abstract The microelectronics industry has seen explosive growth during the last thirty years. Extremely large markets for logic and memory devices have driven the development of new materials, and technologies for the fabrication of even more complex devices with features sizes now down at the sub micron level. Recent interest has arisen in employing these materials, tools and technologies for the fabrication of miniature sensors and actuators and their integration with electronic circuits to produce smart devices and MicroElectroMechanical Systems (MEMS). This effort offers the promise of: 1. Increasing the performance and manufacturability of both sensors and actuators by exploiting new batch fabrication processes developed for the IC and microelectronics industry. Examples include micro stereo lithographic and micro molding techniques. 2. Developing novel classes of materials and mechanical structures not possible previously, such as diamond like carbon, silicon carbide and carbon nanotubes, micro-turbines and micro-engines. 3. Development of technologies for the system level and wafer level integration of micro components at the nanometer precision, such as self-assembly techniques and robotic manipulation. 4. Development of control and communication systems for MEMS devices, such as optical and RF wireless, and power delivery systems.

Design of Electrostatic Micro Mirrors for Improved Stability Though Surface Contact

1998 ◽  
Author(s):  
Timothy Moulton ◽  
G. K. Ananthasuresh
Keyword(s):  
Design Method ◽  
Electrostatic Force ◽  
Electrostatic Actuation ◽  
Mems Devices ◽  
Complex Dynamic ◽  
Micro Electro Mechanical Systems ◽  
Electrostatically Actuated ◽  
Surface Contact ◽  
Improved Stability ◽  
Mems Process

Abstract There exists a need to stabilize the electrostatic actuation commonly used in Micro-Electro-Mechanical Systems (MEMS). Most electrostatically actuated MEMS devices act as variable capacitors with varying gap between the charged conductors. Electrostatic force in these devices is a nonlinear attractive force between the conductors resulting in a complex dynamic system. These systems are stable for only a small portion of the initial gap. In this paper a design method is presented for electrostatic micro-mirrors with improved stability. Controllable, stable electrostatic actuation can be achieved through surface contact between the two conductors. Once in contact with the surface, the compliance of the structure is used to stabilize the electrostatic actuation over a long range of motion. Beam based variable angle mirrors were designed and fabricated using the Multi-User MEMS Process at MCNC technology center. The design methods for stable electrostatic actuation were tested on these mirrors. Some characteristics are noted and their implementation into future designs is discussed.

MEMS-Enabled Smart Beam-Steering Antennas

2014 ◽  
pp. 183-203
Author(s):  
Hadi Mirzajani ◽  
Habib Badri Ghavifekr ◽  
Esmaeil Najafi Aghdam
Keyword(s):  
Microelectromechanical Systems ◽  
Rf Mems ◽  
Beam Steering ◽  
Smart Antennas ◽  
Phase Shifters ◽  
Rapid Rate ◽  
Mems Devices ◽  
Batch Fabrication ◽  
Mems Technology ◽  
Smart Beam

In recent years, Microelectromechanical Systems (MEMS) technology has seen a rapid rate of evolution because of its great potential for advancing new products in a broad range of applications. The RF and microwave devices and components fabricated by this technology offer unsurpassed performance such as near-zero power consumption, high linearity, and cost effectiveness by batch fabrication in respect to their conventional counterparts. This chapter aims to give an in-depth overview of the most recently published methods of designing MEMS-based smart antennas. Before embarking into the different techniques of beam steering, the concept of smart antennas is introduced. Then, some fundamental concepts of MEMS technology such as micromachining technologies (bulk and surface micromachining) are briefly discussed. After that, a number of RF MEMS devices such as switches and phase shifters that have applications in beam steering antennas are introduced and their operating principals are completely explained. Finally, various configurations of MEMS-enabled beam steering antennas are discussed in detail.

A Renewal Weakest-Link Model of Strength Distribution of Polycrystalline Silicon MEMS Structures

2019 ◽  
Vol 86 (8) ◽  
Author(s):  
Zhifeng Xu ◽  
Roberto Ballarini ◽  
Jia-Liang Le
Keyword(s):  
Experimental Data ◽  
Polycrystalline Silicon ◽  
Microelectromechanical Systems ◽  
Strength Distribution ◽  
Material Strength ◽  
Mems Devices ◽  
Efficient Computation ◽  
Weakest Link ◽  
Large Size ◽  
The Stability

Experimental data have made it abundantly clear that the strength of polycrystalline silicon (poly-Si) microelectromechanical systems (MEMS) structures exhibits significant variability, which arises from the random distribution of the size and shape of sidewall defects created by the manufacturing process. Test data also indicated that the strength statistics of MEMS structures depends strongly on the structure size. Understanding the size effect on the strength distribution is of paramount importance if experimental data obtained using specimens of one size are to be used with confidence to predict the strength statistics of MEMS devices of other sizes. In this paper, we present a renewal weakest-link statistical model for the failure strength of poly-Si MEMS structures. The model takes into account the detailed statistical information of randomly distributed sidewall defects, including their geometry and spacing, in addition to the local random material strength. The large-size asymptotic behavior of the model is derived based on the stability postulate. Through the comparison with the measured strength distributions of MEMS specimens of different sizes, we show that the model is capable of capturing the size dependence of strength distribution. Based on the properties of simulated random stress field and random number of sidewall defects, a simplified method is developed for efficient computation of strength distribution of MEMS structures.

scholarly journals Stability Improvement of Flexible Shallow Shells Using Neutron Radiation

Materials ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3187
Author(s):  
Anton V. Krysko ◽  
Jan Awrejcewicz ◽  
Irina V. Papkova ◽  
Vadim A. Krysko
Keyword(s):  
Temperature Field ◽  
Neutron Irradiation ◽  
Microelectromechanical Systems ◽  
Neutron Radiation ◽  
Middle Surface ◽  
Aviation Industry ◽  
Irradiation Effect ◽  
Structural Members ◽  
Mems Devices ◽  
Shallow Shells

Microelectromechanical systems (MEMS) are increasingly playing a significant role in the aviation industry and space exploration. Moreover, there is a need to study the neutron radiation effect on the MEMS structural members and the MEMS devices reliability in general. Experiments with MEMS structural members showed changes in their operation after exposure to neutron radiation. In this study, the neutron irradiation effect on the flexible MEMS resonators’ stability in the form of shallow rectangular shells is investigated. The theory of flexible rectangular shallow shells under the influence of both neutron irradiation and temperature field is developed. It consists of three components. First, the theory of flexible rectangular shallow shells under neutron radiation in temperature field was considered based on the Kirchhoff hypothesis and energetic Hamilton principle. Second, the theory of plasticity relaxation and cyclic loading were taken into account. Third, the Birger method of variable parameters was employed. The derived mathematical model was solved using both the finite difference method and the Bubnov–Galerkin method of higher approximations. It was established based on a few numeric examples that the irradiation direction of the MEMS structural members significantly affects the magnitude and shape of the plastic deformations’ distribution, as well as the forces magnitude in the shell middle surface, although qualitatively with the same deflection the diagrams of the main investigated functions were similar.

Wafer-Level Strength and Fracture Toughness Testing of Surface-Micromachined MEMS Devices

1999 ◽  
Vol 605 ◽  
Author(s):  
H. Kahn ◽  
N. Tayebi ◽  
R. Ballarini ◽  
R.L. Mullen ◽  
A.H. Heuer
Keyword(s):  
Fracture Toughness ◽  
Tensile Strength ◽  
Microelectromechanical Systems ◽  
Reliability Prediction ◽  
Bend Strength ◽  
Mems Devices ◽  
Wafer Level ◽  
Toughness Testing ◽  
Loading Devices

AbstractDetermination of the mechanical properties of MEMS (microelectromechanical systems) materials is necessary for accurate device design and reliability prediction. This is most unambiguously performed using MEMS-fabricated test specimens and MEMS loading devices. We describe here a wafer-level technique for measuring the bend strength, fracture toughness, and tensile strength of MEMS materials. The bend strengths of surface-micromachined polysilicon, amorphous silicon, and polycrystalline 3C SiC are 5.1±1.0, 10.1±2.0, and 9.0±1.0 GPa, respectively. The fracture toughness of undoped and P-doped polysilicon is 1.2±0.2 MPa√m, and the tensile strength of polycrystalline 3C SiC is 3.2±1.2 GPa. These results include the first report of the mechanical strength of micromachined polycrystalline 3C SiC.

Resonant Fatigue Testing of Cantilever Specimens Prepared from Thin Films

2008 ◽  
Vol 1139 ◽  
Author(s):  
Kwangsik Kwak ◽  
Masaaki Otsu ◽  
Kazuki Takashima
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Cantilever Beam ◽  
Microelectromechanical Systems ◽  
Fatigue Testing ◽  
Crystalline Silicon ◽  
Gold Foil ◽  
Fatigue Properties ◽  
Mems Devices ◽  
Testing Method

AbstractFatigue properties of thin film materials are extremely important to design durable and reliable microelectromechanical systems (MEMS) devices. However, it is rather difficult to apply conventional fatigue testing method of bulk materials to thin films. Therefore, a fatigue testing method fitted to thin film materials is required. In this investigation, we have developed a fatigue testing method that uses a resonance of cantilever type specimen prepared from thin films. Cantilever beam specimens with dimensions of 1(W) × 3(L) × 0.01(t) mm3 were prepared from Ni-P amorphous alloy thin films and gold foils. In addition, cantilever beam specimens with dimension of 3(L) × 0.3(W) × 0.005(t) mm3 were also prepared from single crystalline silicon thin films. These specimens were fixed to a holder that is connected to an golddio speaker used as an actuator, and were resonated in bending mode. In order to check the validity of this testing method, Young's moduli of these specimens were measured from resonant frequencies. The average Young's modulus of Ni-P was 108 GPa and that of gold foil specimen was 63 GPa, and these values were comparable with those measured by other techniques. This indicates that the resonance occurred theoretically-predicted manner and this testing method is valid for measuring the fatigue properties of thin films. Resonant fatigue tests were carried out for these specimens by changing amplitude range of resonance, and S-N curves were successfully obtained.

Comparison of Thermomechanical and Stress Wave Induced Laser Repair Techniques for Stiction-Failed Microcantilevers

2004 ◽  
Author(s):  
Sai B. Koppaka ◽  
Thomas J. Mackin ◽  
Leslie M. Phinney
Keyword(s):  
Stress Wave ◽  
Microelectromechanical Systems ◽  
Stress Waves ◽  
Back Side ◽  
Mems Devices ◽  
Repair Method ◽  
Aspect Ratios ◽  
Major Disadvantage ◽  
Initial Processing ◽  
Wave Induced

Surface micromachined structures with high aspect ratios are often utilized as sensor platforms in microelectromechanical systems (MEMS) devices. These structures generally fail by stiction or adhesion to the underlying substrate during operation, or related initial processing. Such failures represent a major disadvantage in mass production of MEMS devices with highly compliant structures. Fortunately, most stiction failures can be prevented or repaired in a number of ways. Passive approaches implemented during fabrication or release include: (1) utilizing special low adhesion coatings and (2) processing with low surface energy rinse agents. These methods, however, increase both the processing time and cost and are not entirely effective. Active approaches, such as illuminating stiction-failed microstructures with pulsed laser irradiation, have proven to be very effective for stiction repair [1–5]. A more recent and promising method, introduced by Gupta et al. [6], utilized laser-induced stress waves to repair stiction-failed microstructures. This approach represents a logical extension of the laser spallation technique for debonding thin films from substrates [7–9]. The method transmits stress waves into MEMS structures by laser-irradiating the back side of the substrate opposite the stiction-failed structures. This paper presents an experimental study that compares the stress wave repair method with the thermomechanical repair method on identical arrays of stiction-failed cantilevers.

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