Multiple Wafer Bonding for MEMS Applications

2001 ◽  
Vol 681 ◽  
Author(s):  
M. Reiche ◽  
M. Haueis ◽  
J. Dual ◽  
C. Cavalloni ◽  
R. Buser
Keyword(s):  
Wafer Bonding ◽  
Microelectromechanical Systems ◽  
Single Crystal Silicon ◽  
Force Sensor ◽  
Semiconductor Wafer ◽  
Crystal Silicon ◽  
Static Loads ◽  
3 Dimensional ◽  
Wafer Direct Bonding ◽  
Better Than

ABSTRACTMost of the microelectromechanical systems (MEMS) require a 3-dimensional architecture which can efficiently be realized by multiple semiconductor wafer direct bonding. The present paper demonstrates the method on a force sensor for high resolution measurements of static loads. To minimize temperature stress an all-in silicon solution was developed in contrast to micromachined resonant force sensors published already in the literature.The presented force sensor integrates load coupling, the excitation and detection of the vibration of the microresonator in one and the same single crystal silicon package. First measurements proved a sensitivity of 26 Hz/N and a resolution better than 3 mN.

Assembly and Testing of Surface Micromachined, Piezoresistive Polysilicon Pressure Sensors

1999 ◽  
Author(s):  
Todd F. Miller ◽  
David J. Monk ◽  
Gary O’Brien ◽  
William P. Eaton ◽  
James H. Smith
Keyword(s):  
Pressure Sensor ◽  
Microelectromechanical Systems ◽  
Pressure Sensors ◽  
Single Crystal Silicon ◽  
Surface Micromachining ◽  
Process Technology ◽  
Crystal Silicon ◽  
Noise Characteristics ◽  
Testing Techniques ◽  
Piezoresistive Pressure Sensors

Abstract Surface micromachining is becoming increasingly popular for microelectromechanical systems (MEMS) and a new application for this process technology is pressure sensors. Uncompensated surface micromachined piezoresistive pressure sensors were fabricated by Sandia National Labs (SNL). Motorola packaged and tested the sensors over pressure, temperature and in a typical circuit application for noise characteristics. A brief overview of surface micromachining related to pressure sensors is described in the report along with the packaging and testing techniques used. The electrical data found is presented in a comparative manner between the surface micromachined SNL piezoresistive polysilicon pressure sensor and a bulk micromachined Motorola piezoresistive single crystal silicon pressure sensor.

Thermal Conductivity of Single-Crystal Silicon Microbridges Measured by Electrical Resistance Thermometry and Time-Domain Thermoreflectance

2012 ◽  
Author(s):  
Timothy S. English ◽  
Leslie M. Phinney ◽  
Patrick E. Hopkins ◽  
Justin R. Serrano
Keyword(s):  
Thermal Conductivity ◽  
Single Crystal ◽  
Time Domain ◽  
Electrical Resistance ◽  
Microelectromechanical Systems ◽  
Single Crystal Silicon ◽  
Operating Conditions ◽  
Equation Modeling ◽  
Crystal Silicon ◽  
Resistance Thermometry

Accurate thermal conductivity values are essential to the modeling, design, and thermal management of microelectromechanical systems (MEMS) and devices. However, the experimental technique best suited to measure thermal conductivity, as well as thermal conductivity itself, varies with the device materials, fabrication conditions, geometry, and operating conditions. In this study, the thermal conductivity of boron doped single-crystal silicon-on-insulator (SOI) microbridges is measured over the temperature range from 77 to 350 K. The microbridges are 4.6 mm long, 125 μm tall, and two widths, 50 or 85 μm. Measurements on the 85 μm wide microbridges are made using both steady-state electrical resistance thermometry and optical time-domain thermoreflectance. A thermal conductivity of ∼ 77 W/mK is measured for both microbridge widths at room temperature, where both experimental techniques agree. However, a discrepancy at lower temperatures is attributed to differences in the interaction volumes and in turn, material properties, probed by each technique. This finding is qualitatively explained through Boltzmann transport equation modeling under the relaxation time approximation.

scholarly journals The Effects of Cold Arm Width and Metal Deposition on the Performance of a U-Beam Electrothermal MEMS Microgripper for Biomedical Applications

Micromachines ◽  
2019 ◽  
Vol 10 (3) ◽  
pp. 167 ◽  
Author(s):  
Marija Cauchi ◽  
Ivan Grech ◽  
Bertram Mallia ◽  
Pierluigi Mollicone ◽  
Nicholas Sammut
Keyword(s):  
Microelectromechanical Systems ◽  
Coefficient Of Thermal Expansion ◽  
Numerical Models ◽  
Lateral Displacement ◽  
Single Crystal Silicon ◽  
Silicon On Insulator ◽  
Adhesion Promoter ◽  
Crystal Silicon ◽  
Element Analysis ◽  
Human Red Blood Cells

Microelectromechanical systems (MEMS) have established themselves within various fields dominated by high-precision micromanipulation, with the most distinguished sectors being the microassembly, micromanufacturing and biomedical ones. This paper presents a horizontal electrothermally actuated ‘hot and cold arm’ microgripper design to be used for the deformability study of human red blood cells (RBCs). In this study, the width and layer composition of the cold arm are varied to investigate the effects of dimensional and material variation of the cold arm on the resulting temperature distribution, and ultimately on the achieved lateral displacement at the microgripper arm tips. The cold arm widths investigated are 14 μ m, 30 μ m, 55 μ m, 70 μ m and 100 μ m. A gold layer with a thin chromium adhesion promoter layer is deposited on the top surface of each of these cold arms to study its effect on the performance of the microgripper. The resultant ten microgripper design variants are fabricated using a commercially available MEMS fabrication technology known as a silicon-on-insulator multi-user MEMS process (SOIMUMPs)™. This process results in an overhanging 25 μ m thick single crystal silicon microgripper structure having a low aspect ratio (width:thickness) value compared to surface micromachined structures where structural thicknesses are of the order of 2 μ m. Finite element analysis was used to numerically model the microgripper structures and coupled electrothermomechanical simulations were implemented in CoventorWare ® . The numerical simulations took into account the temperature dependency of the coefficient of thermal expansion, the thermal conductivity and the electrical conductivity properties in order to achieve more reliable results. The fabricated microgrippers were actuated under atmospheric pressure and the experimental results achieved through optical microscopy studies conformed with those predicted by the numerical models. The gap opening and the temperature rise at the cell gripping zone were also compared for the different microgripper structures in this work, with the aim of identifying an optimal microgripper design for the deformability characterisation of RBCs.

Adhesion and Friction Studies of Silicon and Hydrophobic and Low Friction Films and Investigation of Scale Effects

2004 ◽  
Vol 126 (3) ◽  
pp. 583-590 ◽  
Author(s):  
Bharat Bhushan ◽  
Huiwen Liu ◽  
Stephen M. Hsu
Keyword(s):  
Microelectromechanical Systems ◽  
Scale Effects ◽  
Single Crystal Silicon ◽  
Operating Conditions ◽  
Nanoelectromechanical Systems ◽  
Low Friction ◽  
Self Assembled Monolayer ◽  
Crystal Silicon ◽  
Solid Films ◽  
Friction Measurements

Tribological properties are crucial to the reliability of microelectromechanical systems/nanoelectromechanical systems (MEMS/NEMS). In this study, adhesion and friction measurements are made at micro and nanoscales on single-crystal silicon (commonly used in MEMS/NEMS) and hydrophobic and low friction films. These include diamondlike carbon (DLC), chemically bonded perfluoropolyether (PFPE), and self-assembled monolayer (SAM) films. Since MEMS/NEMS devices are expected to be used in various environments, measurements are made at a range of velocities, humidities, and temperatures. The relevant adhesion and friction mechanisms are discussed. It is found that solid films of DLC, PFPE, and SAM can reduce the adhesion and friction of silicon. These films can be used as anti-adhesion films for MEMS/NEMS components under different environments and operating conditions. Finally, the adhesion and friction data clearly show scale dependence. The scale effects on adhesion and friction are also discussed in the paper.

Micromechanical and tribological characterization of doped single-crystal silicon and polysilicon films for microelectromechanical systems devices

1997 ◽  
Vol 12 (1) ◽  
pp. 54-63 ◽  
Author(s):  
Bharat Bhushan ◽  
Xiaodong Li
Keyword(s):  
Single Crystal ◽  
Microelectromechanical Systems ◽  
Single Crystal Silicon ◽  
Crystal Silicon ◽  
Polysilicon Film ◽  
Type Silicon ◽  
Boron Doped ◽  
Polysilicon Films ◽  
Tribological Characterization

Microelectromechanical systems (MEMS) devices are made of doped single-crystal silicon, LPCVD polysilicon films, and other ceramic films. Very little is understood about tribology and mechanical characterization of these materials on micro- to nanoscales. Micromechanical and tribological characterization of p-type (lightly boron-doped) single-crystal silicon (referred to as “undoped”), p+-type (boron doped) single-crystal silicon, polysilicon bulk, and n+-type (phosphorous doped) LPCVD polysilicon films have been carried out. Hardness, elastic modulus, and scratch resistance of these materials were measured by nanoindentation and microscratching using a nanoindenter. Friction and wear properties were measured using an accelerated ball-on-flat tribometer. It is found that the undoped silicon and polysilicon bulk as well as n+-type polysilicon film exhibit higher hardness and elastic modulus than the p+-type silicon. The polysilicon bulk and n+-type polysilicon film exhibit the lowest friction and highest resistance to scratch and wear followed by the undoped silicon and with the poorest behavior of the p+-type silicon. During scratching, the p+-type silicon deforms like a ductile metal.

Force Response of Single Living Cells Due to Localized Deformation (Invited Talk)

2002 ◽  
Author(s):  
T. Saif ◽  
C. Sager ◽  
S. Coyer
Keyword(s):  
Mechanical Response ◽  
Single Crystal Silicon ◽  
Fibroblast Cell ◽  
Force Sensor ◽  
Local Deformation ◽  
Force Response ◽  
Localized Deformation ◽  
Crystal Silicon ◽  
Micro Electro Mechanical Systems ◽  
Adhesion Site

We present a method for measuring the mechanical response of a single cell in-situ when local deformation is applied at an adhesion site(s) by a functionalized MEMS (Micro Electro Mechanical Systems) force sensor with pN – nN force resolution, and with force and displacement ranges of 100s of nNs and μms. The force sensor is a micro mechanical cantilever beam made of single crystal silicon (SCS), coated by a thin layer of Fibronectin, an extra cellular matrix (ECM) protein, to activate cell adhesion. The end of the beam is brought in contact with a cell to form the adhesion site(s). The cantilever is then moved away from the cell to locally deform it. The force on the cell is measured from the deformation of the cantilever until the adhesion sites fails. We demonstrate the method by deforming several endothelial and fibroblast cells. Force response of the fibroblast cell shows linear behavior.

Experimental Study on Aerodynamics of Microelectromechanical Systems Based Single-Crystal-Silicon Microscale Supersonic Nozzle

2013 ◽  
Vol 135 (8) ◽  
Author(s):  
Moriaki Namura ◽  
Toshiyuki Toriyama
Keyword(s):  
New York ◽  
Single Crystal ◽  
Microelectromechanical Systems ◽  
Supersonic Nozzle ◽  
Single Crystal Silicon ◽  
Internal Flow ◽  
Nozzle Flow ◽  
Crystal Silicon ◽  
Rarefied Flow ◽  
Silicon Bulk

In this paper, the design, microfabrication, and direct measurement of the static pressure distribution for the aerodynamics of a single-crystal-silicon microscale supersonic nozzle are described. The microscale supersonic nozzle has a convergent–divergent section and a throat area of 100μm × 300μm. The microscale supersonic nozzle was fabricated by silicon bulk micromachining technology. The degree of the rarefaction of nozzle flow was determined by the Knudsen number (Kn). The operation envelope that determines whether the continuum or rarefied flow assumption is appropriate can be expressed as a function of Kn and related parameters. The effect of nonadiabatic operation on microscale nozzle flow was investigated on the basis of wall heat transfer. These physical correlations were taken into account for the classical Shapiro's equations to analyze the microscale nozzle flow aerodynamics (Shapiro, 1953, The Dynamics and Thermodynamics of Compressible Fluid Flow, Ronald, New York, Chap. 7,8; Greitzer et al., 2006, Internal Flow, Cambridge University, Cambridge, UK, Chap. 2,10). Furthermore, the solutions of Shapiro's equations were compared with the experimental results by the authors and other research institutions in order to demonstrate the validity of the proposed aerodynamics design concept for microscale continuum flow.

scholarly journals The Effects of Structure Thickness, Air Gap Thickness and Silicon Type on the Performance of a Horizontal Electrothermal MEMS Microgripper

Actuators ◽  
2018 ◽  
Vol 7 (3) ◽  
pp. 38 ◽  
Author(s):  
Marija Cauchi ◽  
Ivan Grech ◽  
Bertram Mallia ◽  
Pierluigi Mollicone ◽  
Nicholas Sammut
Keyword(s):  
Microelectromechanical Systems ◽  
Numerical Models ◽  
Substrate Surface ◽  
Single Crystal Silicon ◽  
Air Gap ◽  
Silicon On Insulator ◽  
Free Standing ◽  
Crystal Silicon ◽  
Element Analysis ◽  
Intrinsic Nature

The ongoing development of microelectromechanical systems (MEMS) over the past decades has made possible the achievement of high-precision micromanipulation within the micromanufacturing, microassembly and biomedical fields. This paper presents different design variants of a horizontal electrothermally actuated MEMS microgripper that are developed as microsystems to micromanipulate and study the deformability properties of human red blood cells (RBCs). The presented microgripper design variants are all based on the U-shape `hot and cold arm’ actuator configuration, and are fabricated using the commercially available Multi-User MEMS Processes (MUMPs®) that are produced by MEMSCAP, Inc. (Durham, NC, USA) and that include both surface micromachined (PolyMUMPs™) and silicon-on-insulator (SOIMUMPs™) MEMS fabrication technologies. The studied microgripper design variants have the same in-plane geometry, with their main differences arising from the thickness of the fabricated structures, the consequent air gap separation between the structure and the substrate surface, as well as the intrinsic nature of the silicon material used. These factors are all inherent characteristics of the specific fabrication technologies used. PolyMUMPs™ utilises polycrystalline silicon structures that are composed of two free-standing, independently stackable structural layers, enabling the user to achieve structure thicknesses of 1.5 μm, 2 μm and 3.5 μm, respectively, whereas SOIMUMPs™ utilises a 25 μm thick single crystal silicon structure having only one free-standing structural layer. The microgripper design variants are presented and compared in this work to investigate the effect of their differences on the temperature distribution and the achieved end-effector displacement. These design variants were analytically studied, as well as numerically modelled using finite element analysis where coupled electrothermomechanical simulations were carried out in CoventorWare® (Version 10, Coventor, Inc., Cary, NC, USA). Experimental results for the microgrippers’ actuation under atmospheric pressure were obtained via optical microscopy studies for the PolyMUMPs™ structures, and they were found to be conforming with the predictions of the analytical and numerical models. The focus of this work is to identify which one of the studied design variants best optimises the microgripper’s electrothermomechanical performance in terms of a sufficient lateral tip displacement, minimum out-of-plane displacement at the arm tips and good heat transfer to limit the temperature at the cell gripping zone, as required for the deformability study of RBCs.

Influences of Exothermic Reactive Layer and Metal Interlayer on Fracture Behavior of Reactively Bonded Solder Joints

2015 ◽  
Vol 137 (3) ◽  
Author(s):  
Takahiro Namazu ◽  
Kohei Ohtani ◽  
Shozo Inoue ◽  
Shugo Miyake
Keyword(s):  
Film Thickness ◽  
Microelectromechanical Systems ◽  
Solder Joints ◽  
Single Crystal Silicon ◽  
Bending Test ◽  
Crystal Silicon ◽  
Fracture Origin ◽  
Four Point Bending ◽  
External Forces

Reactively bonded solder joints with Al/Ni exothermic films attract much attention in semiconductor and microelectromechanical systems (MEMS) industries. Higher bond strength of the joints is required for long-term mechanical reliability. We have investigated the strength of rectangular-solid single crystal silicon (SCS) specimens with reactively bonded Sn-3.5Ag solder joint by using specially developed four-point bending test equipment. In this paper, the influences of Al/Ni exothermic film thickness and metallic interlayer on the strength are discussed. The strength increases with increasing Al/Ni film thickness and pressure load during bonding. Metallic interlayer between the solder and SCS also affects the strength because fracture origin is dependent on the types of metals. The obtained results suggest that reacted NiAl is durable against external forces compared with the solder and interlayer.

Sign in / Sign up

Export Citation Format

Share Document