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.

Importance of Bonding Atmosphere for Mechanical Reliability of Reactively Bonded Solder Joints

2015 ◽  
Vol 138 (1) ◽  
Author(s):  
Shugo Miyake ◽  
Kohei Ohtani ◽  
Shozo Inoue ◽  
Takahiro Namazu
Keyword(s):  
Fracture Surface ◽  
Fracture Strength ◽  
Solder Joints ◽  
Exothermic Reaction ◽  
Single Crystal Silicon ◽  
Crystal Silicon ◽  
Reaction Bonding ◽  
Surface Observation ◽  
Four Point Bending ◽  
Snag Solder

Self-propagating exothermic reaction bonding (SERB) technique with Al/Ni multilayer film is fascinating in the viewpoint of lots of outstanding features, such as atmosphere-independent exothermic reaction and its self-propagation. The reactively bonded solder joints with high bonded strength are required for practical use in semiconductor devices. We have investigated the fracture strength of rectangular-solid specimens with reactively bonded solder joint (Sn–3.5Ag solder/reacted NiAl/Sn–3.5Ag solder) sandwiched by single crystal silicon (SCS). In this paper, the influence of bonding atmosphere on the fracture behavior is discussed by means of four-point bending testing and fracture surface observation. The fracture strength increases with increasing pressure load during bonding. The strength of the vacuum-bonded specimens is found to be higher than that of the air-bonded specimens. The fracture surface observation results suggest that Al oxide and intermetallic compounds (IMCs) formed at the reacted NiAl layer and the SnAg solder layer, respectively, would have affected the strength of the Al/Ni SERB joints.

Long-Term Reliability Assessment of Bioceramics for Artificial Joints Using Microdamage Monitoring by AE

2006 ◽  
Vol 309-311 ◽  
pp. 1191-1194
Author(s):  
Shuichi Wakayama ◽  
Teppei Kawakami ◽  
Junji Ikeda
Keyword(s):  
Critical Stress ◽  
Reliability Assessment ◽  
Physiological Saline ◽  
Bending Test ◽  
Unstable Fracture ◽  
Artificial Joints ◽  
Bending Tests ◽  
Four Point Bending

Microfracture process during bending tests of alumina ceramics used for artificial joints was evaluated by acoustic emission (AE) technique. Four-point bending tests were carried out in air, refined water, physiological saline and simulated body fluid. AE behavior during bending test inhibited the rapid increasing point of AE events and energy prior to the final unstable fracture. It was understood that the bending stress at the increasing point corresponds to the critical stress for maincrack formation. The critical stress was affected by water in environments more strongly than fracture strength. Consequently, it was suggested that the characterization of maincrack formation is essential for the long-term reliability assessment of load-bearing bioceramics.

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 Long-term Laminated Glass Four Point Bending Test with PVB, EVA and SG Interlayers at Different Temperatures

2013 ◽  
Vol 57 ◽  
pp. 996-1004 ◽  
Author(s):  
Tomas Serafinavičius ◽  
Jean-Paul Lebet ◽  
Christian Louter ◽  
Tomas Lenkimas ◽  
Artiomas Kuranovas
Keyword(s):  
Bending Test ◽  
Laminated Glass ◽  
Four Point Bending ◽  
Different Temperatures ◽  
Four Point Bending Test

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.

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.

scholarly journals Bendable Single Crystal Silicon Nanomembrane Thin Film Transistors with Improved Low-Temperature Processed Metal/n-Si Ohmic Contact by Inserting TiO2 Interlayer

Nanomaterials ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 1060 ◽  
Author(s):  
Jiaqi Zhang ◽  
Yi Zhang ◽  
Dazheng Chen ◽  
Weidong Zhu ◽  
He Xi ◽  
...  
Keyword(s):  
Thin Film ◽  
Low Temperature ◽  
Single Crystal ◽  
Ohmic Contact ◽  
Thin Film Transistors ◽  
Single Crystal Silicon ◽  
Bending Test ◽  
Crystal Silicon ◽  
Silicon Nanomembrane ◽  
Tio2 Interlayer

Bendable single crystal silicon nanomembrane thin film transistors (SiNMs TFTs), employing a simple method which can improve the metal/n-Silicon (Si) contact characteristics by inserting the titanium dioxide (TiO2) interlayer deposited by atomic layer deposition (ALD) at a low temperature (90 °C), are fabricated on ITO/PET flexible substrates. Current-voltage characteristics of titanium (Ti)/insertion layer (IL)/n-Si structures demonstrates that they are typically ohmic contacts. X-ray photoelectron spectroscopy (XPS) results determines that TiO2 is oxygen-vacancies rich, which may dope TiO2 and contribute to a lower resistance. By inserting TiO2 between Ti and n-Si, Ids of bendable single crystal SiNMs TFTs increases 3–10 times than those without the TiO2 insertion layer. The fabricated bendable devices show superior flexible properties. The TFTs, whose electrical properties keeps almost unchanged in 800 cycles bending with a bending radius of 0.75 cm, obtains the durability in bending test. All of the results confirm that it is a promising method to insert the TiO2 interlayer for improving the Metal/n-Si ohmic contact in fabrication of bendable single crystal SiNMs TFTs.

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.

Sign in / Sign up

Export Citation Format

Share Document