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.

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.

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.

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.

MECHANICAL BEHAVIOR OF FREESTANDING Mo THIN FILMS FOR RF–MEMS DEVICES

2006 ◽  
Vol 20 (25n27) ◽  
pp. 3757-3762 ◽  
Author(s):  
JAE-HYUN KIM ◽  
HAK-JOO LEE ◽  
SEUNG-WOO HAN ◽  
JUNG-YUP KIM ◽  
JUNG-SIL KIM ◽  
...  
Keyword(s):  
Thin Films ◽  
Mechanical Behavior ◽  
Microelectromechanical Systems ◽  
Rf Mems ◽  
Bending Test ◽  
Mems Devices ◽  
Mechanical Reliability ◽  
Sputtering Deposition ◽  
Stress Strain Relation ◽  
Wireless Telecommunication

Radio frequency microelectromechanical systems (RF–MEMS) are an attractive solution for wireless telecommunication applications. Freestanding films play an important role in RF–MEMS devices. For the successful commercialization of RF–MEMS devices, however, it is necessary to evaluate the mechanical reliability of freestanding films. The first step in the evaluation is to characterize the mechanical behavior of the films. This study focuses on freestanding Mo thin films. Mo test structures with a thickness of 960 nm were fabricated using sputtering deposition and patterned using a surface and bulk micromachining process. The strip-bending test was used to measure the stress–strain relation of the freestanding Mo thin films. The measured elastic modulus, initial stress, and yield strength of Mo thin films are reported.

Numerical Analysis for Thermal Performance of High Power Multi-Chip LED Packaging

2010 ◽  
Vol 139-141 ◽  
pp. 1433-1437
Author(s):  
Kai Lin Pan ◽  
Jiao Pin Wang ◽  
Jing Liu ◽  
Guo Tao Ren
Keyword(s):  
High Power ◽  
Heat Sink ◽  
Heat Dissipation ◽  
Light Emitting Diode ◽  
Three Dimensional ◽  
Junction Temperature ◽  
Light Emitting ◽  
Die Attach ◽  
Dissipation Model ◽  
Key Issues

Heat dissipation and cost are the key issues for light-emitting diode (LED) packaging. In this paper, based on the thermal resistance network model of LED packaging, three-dimensional heat dissipation model of high power multi-chip LED packaging is developed and analyzed with the application of finite element method. Temperature distributions of the current multi-chip LED packaging model are investigated systematically under the different materials of the chip substrate, die attach, and/or different structures of the heat sink and fin. The results show that the junction temperature can be decreased effectively by increasing the height of the heat sink, the width of the fin, and the thermal conductivity of the chip substrate and die attach materials. The lower cost and higher reliability for LED source can be obtained through reasonable selection of materials and structure parameters of the LED lighting system.

Wafer Level Hermetic Packaging for RF-MEMS Devices Using Electroplated Gold Layers

2006 ◽  
pp. 617-620
Author(s):  
Gil Soo Park ◽  
Ji Hyuk Yu ◽  
Sang Won Seo ◽  
Woo Beom Choi ◽  
Kyeong Kap Paek ◽  
...  
Keyword(s):  
Rf Mems ◽  
Mems Devices ◽  
Wafer Level ◽  
Hermetic Packaging

Void Formation and Growth at Solder-Bonded Interfaces in HP LEDs

2014 ◽  
Vol 936 ◽  
pp. 1900-1904 ◽  
Author(s):  
Wei Liu ◽  
Peng Jin
Keyword(s):  
Heat Flux ◽  
Theoretical Basis ◽  
Heat Dissipation ◽  
Void Formation ◽  
Junction Temperature ◽  
Heat Transmission ◽  
High Brightness ◽  
Drive Current ◽  
Accelerated Degradation ◽  
Die Attach

Heat flux inside the HP LED chip is also increasing with the increasing drive current, integration and miniaturization of LED chips. The junction temperature of LED strongly depended on the heat transmission capacity of die attach layer, which provided the heat dissipation channel between the heat generating LED chips and the heat slug. The voids, interrmetallic compounds or a small delamination would lead to the increasing thermal resistance in the die attach layer. In this paper, the reliability of soldered-bonded interfaces was studied in high-brightness LEDs, which were prepared by Cree and currently available on the market. Results revealed that the higher drive currents would lead to the accelerated degradation or failure of treated LEDs. Additionally, the injection current had an important effect on void formation and growth at the solder-bonded interfaces. The larger drive current would induce the delamination between LED die and heat slug. This study provided some guidance for the end users and a theoretical basis for solder-bonded technologies.

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