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.

The Effect of Sample Preparation upon the Fracture Toughness of Microsized TiAl

2005 ◽  
Vol 297-300 ◽  
pp. 2416-2422 ◽  
Author(s):  
T.P. Halford ◽  
D. Rudinal ◽  
Kazuki Takashima ◽  
Yakichi Higo
Keyword(s):  
Fracture Toughness ◽  
Tial Alloy ◽  
Microelectromechanical Systems ◽  
Elevated Temperatures ◽  
Mems Devices ◽  
Testing Methods ◽  
Preparation Methods ◽  
Micro Scale ◽  
Lamellar Orientation ◽  
Toughness Testing

The effective fracture toughness testing of materials intended for application in MicroElectroMechanical Systems (MEMS) devices is required in order to improve understanding of how they may be expected to perform upon the micro scale. γ-TiAl based materials are being considered for application in MEMS devices required to operate at elevated temperatures. The effect of different preparation methods upon resulting fracture toughness and development of testing methods for these devices is therefore of importance. Micro-sized cantilevers of the γ-TiAl alloy “Alloy 7” (Ti-46Al-5Nb-1W) were therefore prepared using either mechanical or chemical final stage polishing and subsequently used to evaluate fracture toughness. The effectiveness of the evaluation of micro-sized samples of γ-TiAl in this manner is considered, as well as the effects of the different processing methods and variations in properties according to lamellar orientation.

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.

Area-Selective Adhesive Bonding Using Photosensitive BCB for WL CSP Applications

2005 ◽  
Vol 127 (1) ◽  
pp. 7-11 ◽  
Author(s):  
A. Polyakov ◽  
M. Bartek ◽  
J. N. Burghartz
Keyword(s):  
Fracture Toughness ◽  
Tensile Strength ◽  
Wafer Bonding ◽  
Potential Application ◽  
Adhesive Bonding ◽  
Wafer Level ◽  
Chip Scale Package ◽  
Rf Applications

This paper reports on an area-selective adhesive wafer bonding, using photosensitive BCB from Dow Co. The strength of the fabricated bonds is characterized using the wedge-opening and tensile methods. The measured fracture toughness is 53.5±3.9J/m2 with tensile strength up to 71 MPa. The potential application of BCB bonding is demonstrated on a concept of wafer-level chip-scale package for RF applications and microfilter array for microfluidic applications.

Determination of Rock Fracture Toughness K IIC and its Relationship with Tensile Strength

2011 ◽  
Vol 44 (5) ◽  
pp. 621-627 ◽  
Author(s):  
Yan Jin ◽  
Jianbo Yuan ◽  
Mian Chen ◽  
K. P. Chen ◽  
Yunhu Lu ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Tensile Strength ◽  
Rock Fracture ◽  
Rock Fracture Toughness

Determination of the Fracture Toughness Parameters for an MDF Cement Composite

1985 ◽  
Vol 64 ◽  
Author(s):  
M. Arzamendi ◽  
R. L. Sierakowski ◽  
W. E. Wolfe
Keyword(s):  
Fracture Toughness ◽  
Cement Composite ◽  
Compact Tension ◽  
Test Methods ◽  
Standard Test ◽  
Elastic Behavior ◽  
Hardened Cement ◽  
Linear Elastic ◽  
Toughness Testing

ABSTRACTThe experimental results of fracture toughness testing of a Macro Defect (MDF) Free cement are presented. The material, a hydraulic cement with hydrolyzed polyvinyl polymers, behaves much like a hardened ceramic with measured maximum compressive and tensile strengths of 380 MN/m2 and 69 MN/m2 respectively. Fracture toughness tests were performed on compact tension (CT) and single edge notched beam (SENB) specimens cut from test panels which were supplied in 3mm, 5mm and 10mm thicknesses. The results were evaluated with respect to the fracture toughness parameter Kic using a modification of standard test methods as determined by observed natural behavior. The MDF material exhibited an essentially linear elastic behavior with a fracture toughness slightly higher than typical values recorded for hardened cement paste.

Experimental Research and Analysis of Non-alloy Structural Steel Response Exposed to High Temperature Conditions

2013 ◽  
Vol 32 (2) ◽  
pp. 163-169
Author(s):  
Josip Brnic ◽  
Goran Turkalj ◽  
Sanjin Krscanski
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Tensile Strength ◽  
Structural Steel ◽  
Impact Energy ◽  
Charpy Impact ◽  
Experimental Results ◽  
Charpy Impact Energy ◽  
Over Time

AbstractThis paper presents and analyzes the responses of non-alloy structural steel (1.0044) subjected to uniaxial stresses at high temperatures. This research has two important determinants. The first one is determination of stress-strain dependence and the second is monitoring the behavior of materials subjected to a constant stress at constant temperature over time. Experimental results refer to mechanical properties, elastic modulus, total elongations, creep resistance and Charpy V-notch impact energy. Experimental results show that the tensile strength and yield strength of the considered material fall when the temperature rises over 523 K. Significant decrease in value is especially noticeable when the temperature rises over 723 K. In addition, engineering assessment of fracture toughness was made on the basis of Charpy impact energy. It is visible that when temperature raises then impact energy increases very slightly.

RF MEMS Switch Heat Dissipation in Discrete and Wafer-Level MEMS Packages

2002 ◽  
Author(s):  
Lei L. Mercado ◽  
Tien-Yu Tom Lee ◽  
Shun-Meen Kuo ◽  
Vern Hause ◽  
Craig Amrine
Keyword(s):  
Power Density ◽  
Contact Area ◽  
Heat Dissipation ◽  
Microelectromechanical Systems ◽  
Rf Mems ◽  
Material Selection ◽  
Junction Temperature ◽  
Mems Devices ◽  
Wafer Level ◽  
Die Attach

In discrete RF (Radio Frequency) MEMS (MicroElectroMechanical Systems) packages, MEMS devices were fabricated on Silicon or GaAs (Galium Arsenide) chips. The chips were then attached to substrates with die attach materials. In wafer-level MEMS packages, the switches were manufactured directly on substrates. For both types of packages, when the switches close, a contact resistance of approximately 1 Ohm exists at the contact area. As a result, during switch operations, a considerable amount of heat is generated in the minuscule contact area. The power density at the contact area could be up to 1000 times higher than that of typical power amplifiers. The high power density may overheat the contact area, therefore affect switch performance and jeopardize long-term switch reliabilities. In this paper, thermal analysis was performed to study the heat dissipation at the switch contact area. The goal is to control the “hot spots” and lower the maximum junction temperature at the contact area. A variety of chip materials, including Silicon, GaAs have been evaluated for the discrete packages. For each chip material, the effect of die attach materials was considered. For the wafer-level packages, various substrate materials, such as ceramic, glass, and LTCC (Low-Temperature Cofire Ceramic) were studied. Thermal experiments were conducted to measure the temperature at the contact area and its vicinity as a function of DC and RF powers. Several solutions in material selection and package configurations were explored to enable the use of MEMS with chips or substrates with relatively poor thermal conductivity.

The Fracture Toughness of Polysilicon Microdevices

1998 ◽  
Vol 518 ◽  
Author(s):  
R. Ballarini ◽  
R.L. Mullen ◽  
H. Kahn ◽  
A.H. Heuer
Keyword(s):  
Fracture Toughness ◽  
Microelectromechanical Systems ◽  
Maximum Tensile Stress ◽  
Monotonic Loading ◽  
Modulus Of Rupture ◽  
External Loading ◽  
Mems Devices ◽  
Average Maximum ◽  
Average Modulus ◽  
On Chip

AbstractThe development of polysilicon fracture mechanics specimens with characteristic dimensions comparable to those of typical microelectromechanical systems (MEMS) devices is presented. The notched cantilever specimens are fully integrated with a simultaneously microfabricated electrostatic actuator, which allows on-chip testing of the specimens without the need of an external loading device, and without any possible influences from external sources. Under monotonic loading, the average maximum tensile stress (strength) and average nominal fracture toughness were measured as 4.2 GPa and 3.5 MPa-m½ for boron-doped specimens, and 5.0 GPa and 4.0 MPa-m½ for undoped specimens. An average modulus of rupture of 3.3 GPa and average nominal toughness of 2.7 MPa-m½ were measured for specimens cracked under cyclic resonance loading. The differences between the monotonic loading and cyclic loading data are attributed to fatigue initiation of a sharp crack from the 1 ýtm radius notch. The experimental data is consistent with a critical flaw size in the fabricated devices, a, that is related to the fracture toughness Klc by Klc/a1/2=4600 MPa.

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