Hermetic Packaging of Micro Scanner for Laser Display Applications

2005 ◽  
Author(s):  
Won Kyoung Choi ◽  
Moon Gi Cho ◽  
Sun Kyoung Seo ◽  
Hyuck Mo Lee ◽  
Byung Gil Jeong ◽  
...  
Keyword(s):  
Shear Strength ◽  
Good Adhesion ◽  
Raster Scanning ◽  
Hermetic Packaging ◽  
Laser Display ◽  
Hermetic Sealing ◽  
Experiment Method ◽  
Environmental Variations ◽  
Long Lifetime ◽  
Hermetic Package

Laser display technologies have been developed for an excellent expression of natural color, low power consumption and a long lifetime compared to other advanced displays, such as LCD, PDP and other projection type displays. The micro scanner is one of the key devices to make possible the raster scanning type laser projection displays. And the hermetic package of the micro scanner should be required for the protection from the environmental variations so as to keep the driving behavior uniform. Hermetic package can be ensured when the package is sealed hermetically without generating any outgases in the cavity. Thus, the hermetic sealing process was optimized through DOE (Design of Experiment) method using the Sn-In-Ag solder alloys instead of adhesives. And the characterizations of the packages were carried out in terms of hermeticity, shear strength, and interface microstructures. As a result, we’ve got about 2E−9 atm cc/sec He leak rate, which is low enough to pass the standard (MIL-STD-883E). Shear strength was as high as ∼80 MPa. The C-mode SAM images showed the continuous sealing area without any voids. In addition, the interfacial microstructures revealed good adhesion to the both parts, the glass lid and the ceramic package.

Investigation of Effective Parameters on Cladded Plate Delamination During Pressure Vessels Head Manufacturing by FEM and DOE

2020 ◽  
Author(s):  
Mahmoud Afshari ◽  
Alireza Fallahi Arezodar ◽  
Iraj Sattarifar
Keyword(s):  
Shear Strength ◽  
Strain Energy Release ◽  
Base Plate ◽  
Pressure Vessels ◽  
Strength Increase ◽  
Effective Parameters ◽  
Common Criteria ◽  
Experiment Method ◽  
Element Technique ◽  
Mesh Technique

Abstract Roll-Bond cladded plates are widely used in industry. Stainless steels, Ni, Cu and Ti are used as clad usually. In multi-piece head manufacturing, while these plates press to form petals, delamination occurs in some cases. In this paper, the effective parameters on delamination are investigated. Because of more widely used in respective industry, SA 516 GR 70 as base plate and SS 316L as clad are selected. First of common criteria for defining delamination, the strain energy release rate (SERR), as explanatory parameter selected and calculated using finite element technique and VCCT method. Interface is modeled as cohesive zone with tied mesh technique and by validated experimental work. The design of experiment method is response surface methodology (RSM), and effect of input parameters on output parameter, SERR, is obtained. Results indicate that head radius have greatest impact on G and then thickness of the plate, pressing force, number of pressing steps, shear strength and friction coefficient are placed in the next rows. Among these, when the radius of the head and shear strength increase, SERR decrease and the head radius impact is much greater than shear strength. Finally, in order to prevent delamination, some strategies have been proposed.

Performance of a raster scanning laser display system using diamond shaped frame supported micromirror

2006 ◽  
Vol 18 (16) ◽  
pp. 1702-1704 ◽  
Author(s):  
Chang-Hyeon Ji ◽  
Moongoo Choi ◽  
Sang-Cheon Kim ◽  
See-Hyung Lee ◽  
Jong-Uk Bu
Keyword(s):  
Scanning Laser ◽  
Display System ◽  
Raster Scanning ◽  
Laser Display

Evaluation of the Apparent Interfacial Shear Strength of Nanocellulose/PVA Composites

2018 ◽  
Vol 774 ◽  
pp. 54-59
Author(s):  
Janis Andersons ◽  
I. Filipova ◽  
Mikelis Kirpluks ◽  
Ugis Cabulis
Keyword(s):  
Shear Strength ◽  
Interfacial Shear Strength ◽  
Stress Transfer ◽  
Strain Curve ◽  
Interfacial Shear ◽  
Good Adhesion ◽  
Neat Polymer ◽  
Shear Yield ◽  
Composite Properties

Nanocellulose in the form of whiskers and nanofibers has become a promising reinforcement material for polymer composites due to its high mechanical characteristics and sustainability. For optimization of composite properties, efficient means of characterization of the stress transfer between fibrous nanofiller and the polymer matrix are needed. In the current work, the apparent interfacial shear strength (IFSS) of cellulose nanofiber/PVA is evaluated by a modified Bowyer and Bader method based on an analysis of the stress–strain curve of a composite film in uniaxial tension. The IFSS is found to exceed shear yield strength of the neat polymer, suggesting good adhesion.

Polymer-Based Hermetic Packaging for Flexible Micro Devices

2012 ◽  
Vol 2012 (DPC) ◽  
pp. 001139-001162
Author(s):  
Li-Anne Liew ◽  
Ching-Yi Lin ◽  
Y. C. Lee
Keyword(s):  
High Temperature ◽  
Water Loss ◽  
Absorption Rate ◽  
Microelectromechanical Systems ◽  
Heat Pipes ◽  
Gas Permeation ◽  
High Moisture ◽  
Hermetic Packaging ◽  
Hermetic Sealing ◽  
Bond Interface

In recent years, polymers have been widely adopted as a low-cost, light-weight and high-flexibility alternative to traditional silicon materials for MEMS. However, the majority of polymers do not provide hermetic protection because of their high moisture- and gas permeation rates. Yet, hermetic packaging is critical for many applications such as medical devices [1], RF MEMS [2] and micro heat pipes [3]. In particular, our group has been developing flexible thermal ground planes based on heat pipe technology [3] for advanced electronics cooling applications. Heat pipes require hermetic sealing, while flexibility requires the structural material to be polymer-based. Hermetic packaging methods for MEMS typically include welding, soldering [4], and various epoxies and polymers [1, 2, 5] to bond the parts in a package together. The bond interface is a major potential source of gas and moisture leakage. Although welds and solder joints offer effective hermetic seals, the bond interface is mechanically rigid. On the other hand, flexible bond materials like epoxies typically possess high moisture absorption rate and bonding strength degradation at high temperature [6] while polymers such as BCB [2] or LCP [7] either provide only semi-hermetic sealing or degrade at high temperature. We report a polymer-based hermetic packaging approach using fluorinated ethylene propylene (FEP), which possesses flexibility, high operating temperature compatibility (204°C), chemical resistance, and low water absorption rate. We report results of hermeticity tests in which FEP, solder, and epoxy were used to bond a copper-clad kapton “lid” onto a water-containing copper vessel which is then kept in an oven at 100 °C. The only path for water loss is through the bond interface. We show that the FEP-bonded test vehicles result in negligible water loss comparable to the solder-bonded containers, and far outperforming the epoxy-bonded containers. References: [1] G. Jiang and D. D. Zhou (Ed.), Implantable Neural Prostheses 2, (2010). [2] A Jourdain, P De Moor, K Baert, I DeWolf and H A C Tilmans, J. Micromech. Microeng.,15 (2005) S89–S96. [3] C.J. Oshman, B. Shi, C. Li, R. Yang, Y.C. Lee, G.P. Peterson, and V.M. Bright, J. Microelectromechanical Systems, 20, 2 (2011), 410–417. [4] T. Rude, J. Subramanian, J. Levin, D. Van Heerden, O. Knio, Proc. IMAPS 2005. [5] G. B. Tepolt, M. J. Meschera, J. J. LeBlanca, R. Lutwakb, M. Varghesec, Proc. of SPIE, Vol. 7592, 2010, 759207. [6] E. M. Petrie, Handbook of Adhesives and Sealants, 1st Ed. (McGraw-Hill, 1999), p. 707. [7] C.-D. Ghiu, S. Dalmia, J. Vickers, L. Carastro, W. Czakon, V. Sundaram, G. White, Proc. 1st European Microwave Integrated Circuits Conference, 2006, pp.545–547.

Liquid Crystal Polymer for RF MEMS Packaging

2005 ◽  
Author(s):  
Faheem F. Faheem ◽  
Y. C. Lee
Keyword(s):  
Liquid Crystal ◽  
Flip Chip ◽  
Rf Mems ◽  
Low Cost ◽  
Liquid Crystal Polymer ◽  
Mems Devices ◽  
Hermetic Packaging ◽  
Crystal Polymer ◽  
Membrane Characterization ◽  
Hermetic Sealing

We have developed a liquid crystal polymer (LCP) encapsulation technology for RF MEMS. The RF MEMS devices are flip-chip interconnected with other circuit elements on an alumina substrate. After flip-chip device transfer, LCP is used to encapsulate the device on the substrate. This approach is similar to glob-top encapsulation used for low-cost microelectronic packaging. The effectiveness of LCP (Vectra A950) sealing has been demonstrated by monitoring the moisture level inside the package under a 100% RH environment. In addition, the LCP’s permeabilities to helium and nitrogen were measured through a standard membrane characterization setup. These permeabilities were proven to be in the same level as those of glasses used for hermetic sealing. LCP is an excellent encapsulation material for hermetic or near-hermetic packaging of RF MEMS.

The Thickness-Ratio Effects of Ni/Nb Electrode on Wire Bonding Strength with N-Type 4H-SiC

2012 ◽  
Vol 717-720 ◽  
pp. 829-832
Author(s):  
Kunhwa Jung ◽  
Daisuke Ando ◽  
Yuji Sutou ◽  
Tetsuya Oyamada ◽  
Masamoto Tanaka ◽  
...  
Keyword(s):  
Shear Strength ◽  
Electrical Contact ◽  
Thickness Ratio ◽  
Power Device ◽  
High Shear ◽  
Good Adhesion ◽  
Contact Property ◽  
Device Applications ◽  
Carbon Precipitation ◽  
High Shear Strength

The thickness-ratio effects of Ni/Nb bi-layer electrodes were studied for power device applications. The reaction microstructure and electrical contact property were investigated after annealing at 1000 °C and compared with the results of an Ni electrode. Microstructure-related problems of the Ni electrode could be successfully resolved without sacrificing ohmic contact behavior by the addition of Nb to a Ni based electrode. Carbon precipitation was reduced with increasing Nb thickness by the formation of carbides, which led to good adhesion between the electrode and a wiring pad. High shear strength of the bonded wire was also obtained by the elimination of the carbon precipitates on the electrode surface.

Reliability of Hermetic RF MEMS Wafer Level Packaging Using Au-Sn Eutectic Bonding

2006 ◽  
Vol 326-328 ◽  
pp. 609-612
Author(s):  
Qian Wang ◽  
Sung Hoon Choa ◽  
Woon Bae Kim ◽  
Jun Sik Hwang ◽  
Suk Jin Ham ◽  
...  
Keyword(s):  
Shear Strength ◽  
Low Temperature ◽  
Insertion Loss ◽  
Rf Mems ◽  
Wafer Level ◽  
Eutectic Bonding ◽  
Wafer Level Packaging ◽  
Hermetic Sealing ◽  
Multilayer Metallization

In this paper, a low temperature hermetic wafer level packaging scheme for the RFMEMS devices is presented. For hermetic sealing, Au-Sn multilayer metallization with a square loop of 70 %m in width is performed. The size of the MEMS package is 1mm × 1mm × 700 %m. The shear strength and hermeticity of the package satisfy the requirements of MIL-STD-883F. The total insertion loss for the packaging is 0.075 dB at 2 GHz.

The discrete vacuum packaging of IR-microbolometers

2015 ◽  
Vol 2015 (DPC) ◽  
pp. 001123-001139
Author(s):  
Luca Mauri
Keyword(s):  
Inertial Sensors ◽  
Point Of View ◽  
Sensing Element ◽  
Micro Electro Mechanical Systems ◽  
Vacuum Sealing ◽  
Hermetic Packaging ◽  
Die Attach ◽  
Hermetic Sealing ◽  
Target Pressure ◽  
Device Lifetime

Packaging of Micro Electro Mechanical Systems (MEMS) requires technical challenges to be solved and overcome when stringent vacuum and hermetic sealing is required. This is typical for a wide class of devices, such as inertial sensors, MEMS atomic clocks, IR micro-bolometers, where such conditions need to be achieved to provide the performance stability during the lifetime of the devices. The most challenging vacuum requirements are related to micro-bolometers, since good vacuum level is needed for thermal insulation. Typical target pressure is ≈ 10-3 – 10-4 mbar. Vacuum hermetic packaging can be successfully achieved by dedicated getter film integration, key technology for vacuum requirements, in combination with a specific sealing process and choice of vacuum compatible materials. The discrete packaging of the device requires the attachment of the sensing element into a ceramic package, like LCC. Typically, adhesives are used as die attach material. From the vacuum point of view, adhesives are not ideal candidates and therefore the compatibility with stringent vacuum requirements is not always guaranteed. Preliminary outgassing tests on these components are recommended to select appropriate materials. Thermal treatment of components is another key point for vacuum sealing, since specific degassing treatments before and during sealing can effectively reduce the amount of gas inside the volume of the device. The getter film integration is mandatory in such kind of devices because of the stringent vacuum requirements. SAES' proprietary technology is fully compliant with micro-bolometer manufacturing and the optimization of the getter activation step, during the bonding process, enables the functionality of the device along its lifetime. Moreover, capabilities of performing residual gas analyses and leak rate measurements of sealed devices are fundamental for quality control of vacuum sealing as well as for analyses and prediction of device lifetime.

An investigation of hardness and adhesion of sputter-deposited aluminum on silicon by utilizing a continuous indentation test

1988 ◽  
Vol 3 (1) ◽  
pp. 141-147 ◽  
Author(s):  
D. Stone ◽  
W. R. LaFontaine ◽  
P. Alexopoulos ◽  
T. -W. Wu ◽  
Che-Yu Li
Keyword(s):  
Shear Strength ◽  
Physical Model ◽  
Indentation Test ◽  
Good Adhesion ◽  
Aluminum Films ◽  
Rate Of Increase ◽  
Sputter Deposited ◽  
Film Substrate ◽  
Continuous Indentation ◽  
Poor Adhesion

The hardness of aluminum films on silicon are measured as functions of depth of the indenter. The films have thicknesses of 0.25,0.5, and 1.0μm. The adhesion between one film and the substrate has been reduced through the prior deposition of a 10 nm layer of carbon. In each case the hardness is found to increase as the indenter approaches the film-substrate interface, but the rate of increase is greater for a film with good adhesion than for one with poor adhesion. It is suggested that this increase results from the constraint on deformation of the film by the substrate. A physical model is proposed whereby the yield stress of the film, σo, and an average effective shear strength τ of the indenter-film and film-substrate interfaces, may be determined from the data.

Quality films from carbon fiber evaporation for thorough coverage of TEM grids

1988 ◽  
Vol 46 ◽  
pp. 418-419
Author(s):  
N. Tempel ◽  
M. C. Ledbetter
Keyword(s):  
Electron Microscopy ◽  
High Resolution Electron Microscopy ◽  
Carbon Films ◽  
Low Noise ◽  
Vacuum Evaporation ◽  
High Yield ◽  
Good Adhesion ◽  
Noise Structure ◽  
Resolution Electron ◽  
Carbon Foils

Carbon films have been a support of choice for high resolution electron microscopy since the introduction of vacuum evaporation of carbon. The desirable qualities of carbon films and methods of producing them has been extensively reviewed. It is difficult to get a high yield of grids by many of these methods, especially if virtually all of the windows must be covered with a tightly bonded, quality film of predictable thickness. We report here a method for producing carbon foils designed to maximize these attributes: 1) coverage of virtually all grid windows, 2) freedom from holes, wrinkles or folds, 3) good adhesion between film and grid, 4) uniformity of film and low noise structure, 5) predictability of film thickness, and 6) reproducibility.Our method utilizes vacuum evaporation of carbon from a fiber onto celloidin film and grid bars, adhesion of the film complex to the grid by carbon-carbon contact, and removal of the celloidin by acetone dissolution. Materials must be of high purity, and cleanliness must be rigorously maintained.

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