Fabrication of Tall Structures for Microelectronics Application Using Selective Electrodeposition Process

2010 ◽  
Vol 2010 (1) ◽  
pp. 000947-000953
Author(s):  
Bernd Scholz ◽  
WeiYang Lim ◽  
Ferdous Sarwar ◽  
Syed Sajid Ahmad ◽  
Aaron Reinholz
Keyword(s):  
Aspect Ratio ◽  
Microelectronics Packaging ◽  
Electrodeposition Process ◽  
Tall Structures ◽  
Novel Approach ◽  
Development Processes ◽  
Thick Photoresist ◽  
Vertical Walls

Fabrication of tall features using selective electrodeposition is well known process and has several applications in microelectronics packaging. The use of conventional exposure and development processes is limited by the aspect ratio and sizes of the features obtained. This paper describes a novel approach to fabricated tall structures featured in thick photoresist . Tin and copper tall structures were made by selective electrodeposition. Also presented are results from experiments performed to fabricate tall tin and copper pillars with nearly vertical walls on bare dices to form interconnect.

The Effect of the Top Wall Temperature on the Laminar Natural Convection in Rectangular Cavities With Different Aspect Ratios

2009 ◽  
Vol 131 (5) ◽  
Author(s):  
Wenjiang Wu ◽  
Chan Y. Ching
Keyword(s):  
Natural Convection ◽  
Aspect Ratio ◽  
Wall Temperature ◽  
Vertical Wall ◽  
Flow Region ◽  
Temperature Profiles ◽  
Aspect Ratios ◽  
Vertical Walls ◽  
C And N ◽  
Laminar Natural Convection

The effect of the top wall temperature on the laminar natural convection in air-filled rectangular cavities driven by a temperature difference across the vertical walls was investigated for three different aspect ratios of 0.5, 1.0, and 2.0. The temperature distributions along the heated vertical wall were measured, and the flow patterns in the cavities were visualized. The experiments were performed for a global Grashof number of approximately 1.8×108 and nondimensional top wall temperatures from 0.52 (insulated) to 1.42. As the top wall was heated, the flow separated from the top wall with an undulating flow region in the corner of the cavity, which resulted in a nonuniformity in the temperature profiles in this region. The location and extent of the undulation in the flow are primarily determined by the top wall temperature and nearly independent of the aspect ratio of the cavity. The local Nusselt number was correlated with the local Rayleigh number for all three cavities in the form of Nu=C⋅Ran, but the values of the constants C and n changed with the aspect ratio.

Numerical Study of Thermal Convection in Boussinesq-Stokes Suspension Occupying a Rectangular Box

2011 ◽  
Author(s):  
S. Manjunath ◽  
N. P. Chandrashekara
Keyword(s):  
Aspect Ratio ◽  
Thermal Convection ◽  
Couple Stress ◽  
Numerical Study ◽  
Critical Rayleigh Number ◽  
Vertical Direction ◽  
Heat Conducting ◽  
Linear Temperature ◽  
Vertical Walls ◽  
Vertical Cavity

This paper is a Fourier–series assisted numerical study of two-dimensional thermal convection in Boussinesq–Stokes suspensions occupying a cavity. The suspension is modeled as a couple stress liquid. The horizontal walls of the cavity are assumed to be perfectly heat conducting and the vertical walls are non-uniformly heated to establish a linear temperature in the vertical direction. The critical Rayleigh number is obtained numerically as a function of couple stress parameter and aspect ratio, and the same is plotted graphically. The results of slender vertical cavity, classical Rayleigh-Be´nard convection, rectangular and square cavities of finite aspect-ratio heated from below are obtained as limiting cases of the study.

A thick photoresist process for high aspect ratio MEMS applications

2016 ◽  
Author(s):  
Elias Laforge ◽  
Ricky Anthony ◽  
Paul McCloskey ◽  
Cian O'Mathúna
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Thick Photoresist

Novel positive-tone thick photoresist for high aspect ratio microsystem technology

2002 ◽  
Vol 8 (4-5) ◽  
pp. 326-329 ◽  
Author(s):  
G.-W. Hsieh ◽  
Y.-S. Hsieh ◽  
C.-R. Yang ◽  
Y.-D. Lee
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Microsystem Technology ◽  
Thick Photoresist

scholarly journals A Novel Approach of Heat Rate Enhancement in Rectangular Channels with Thin Porous Layer at the Channel Walls

Sci ◽  
2021 ◽  
Vol 3 (4) ◽  
pp. 42
Author(s):  
Mohamad Ziad Saghir
Keyword(s):  
Reynolds Number ◽  
Aspect Ratio ◽  
Porous Material ◽  
Heat Rate ◽  
Reynolds Numbers ◽  
Heat Extraction ◽  
Metallic Foam ◽  
Novel Approach ◽  
Rectangular Channels ◽  
Porous Strip

Heat transfer enhancement is a topic of great interest nowadays due to its different applications in industries. A porous material also known as metallic foam plays a major role in heat enhancement at the expense of pressure drop. The flow in channels demonstrates the usefulness of this technology in heat extraction. In our current study, a porous strip attached to the walls of the channels is proposed as an alternative for heat enhancement. The thickness of the porous strip was varied for different Reynolds numbers. By maintaining a laminar regime and using water as a fluid, we determined an optimum thickness of porous material leading to the highest performance evaluation criterion. In our current study, with the aspect ratio being the porous strip thickness over the channel width, an aspect ratio of 0.2 is found to be the alternative. A 40% increase in heat enhancement is detected in the presence of a porous strip when compared to a clear channel case for a Reynolds number equal to 200, which improves further as the Reynolds number increases accordingly.

scholarly journals Novel Approach of Heat Rate Enhancement in a Rectangular Channels with Thin Porous Layer at the Channel Walls

2021 ◽  
Author(s):  
M. Z. Saghir
Keyword(s):  
Reynolds Number ◽  
Aspect Ratio ◽  
Porous Material ◽  
Heat Rate ◽  
Heat Extraction ◽  
Metallic Foam ◽  
Novel Approach ◽  
Rectangular Channels ◽  
Porous Strip ◽  
Drop Flow

Heat enhancement is a topic of great interest nowadays due to its different application in industries. Porous material also known as metallic foam plays a major role in heat enhancement at the expenses of pressure drop. Flow in channels demonstrate the usefulness of this technology in heat extraction. In our current study, a porous strip attached to the channels walls is proposed as an alternative for heat enhancement. The thickness of the porous strip was varied for different Reynolds number. By maintaining laminar regime and using water as fluid, we determined an optimum thickness of porous material leading to the highest performance evaluation criterion. In our current study with the aspect ratio being the porous strip thickness over the channel width, an aspect ratio of 0.2 is found to be the alternative. A 40% increase in heat enhancement is detected in the presence of porous strip when compared to a clear channel case for a Reynolds number equal to 200 and improve further as the Reynolds number increase accordingly.

A Novel Approach for Enhancing Critical FIB Imaging for Failure Analysis and Circuit Edit Applications

2004 ◽  
Author(s):  
Joseph Myers ◽  
Marsha Abramo ◽  
Michael Anderson ◽  
Michael W. Phaneuf
Keyword(s):  
Aspect Ratio ◽  
Failure Analysis ◽  
Secondary Electron ◽  
Semiconductor Device ◽  
Ion Beam ◽  
Sample Surface ◽  
Beam Current ◽  
Shielding Effect ◽  
Endpoint Detection ◽  
Novel Approach

Abstract As semiconductor device features continue to decrease in size from merely sub micron to below 100 nanometers it becomes necessary to mill smaller and higher aspect ratio FIB vias with reduced ion beam current. This significantly reduces the number of secondary electrons and ions available for endpoint detection and imaging. In addition FIB gas assisted etching introduces a gas delivery nozzle composed of conductive material. This component is grounded to prevent charge build up during ion beam imaging or milling. The proximity of the nozzle to the sample surface creates a shielding effect which reduces the secondary electron detection level as well [1]. The ability to enhance secondary electron imaging for end point detection is required for successful FIB circuit edit and failure analysis applications on advanced technologies. This paper reviews the results obtained using FIB Assist, an image and signal enhancement product for the FEI / Micrion platform, for critical FIB endpoint determination. Examples of FIB fabricated probe points with 30 x 30 nm FIB vias and circuit edit applications endpointing on metal 1 with high aspect ratio holes are presented.

High Rayleigh Number Laminar Convection in Low Aspect Ratio Enclosures With Adiabatic Horizontal Walls and Differentially Heated Vertical Walls

1982 ◽  
Vol 104 (1) ◽  
pp. 103-110 ◽  
Author(s):  
J. Tichy ◽  
A. Gadgil
Keyword(s):  
Aspect Ratio ◽  
Flow Regime ◽  
Numerical Solutions ◽  
Temperature Profiles ◽  
Approximate Analysis ◽  
Nusselt Numbers ◽  
Numerical Studies ◽  
Vertical Walls ◽  
Laminar Convection ◽  
Rayleigh Numbers

Laminar flow in shallow horizontal cavities (aspect ratio a < < 1) at high Rayleigh numbers (> 106) is investigated using an approximate analysis based on first principles, and also with numerical solutions to the full equations. A Prandtl number of approximately one is assumed. It is found that the flow regime at such high values of Ra is characterized by boundary layers lining both vertical as well as horizontal walls of the enclosure, and is qualitatively different from the flow regimes at lower Rayleigh numbers. The internal region of the core (near to the horizontal centerline) exhibits linear velocity and temperature profiles. Typical isotherms and streamlines characteristic of this flow regime are presented, based on the numerical solutions. The velocity and temperature profiles predicted from the approximate analysis are found to compare well with those obtained from the numerically obtained solutions. The Nusselt numbers predicted from the analysis are also in good agreement with the numerical solutions, and with the limited experimental data in the literature. The various physical processes in this type of flow are discussed based on the findings of the analytical and numerical studies.

scholarly journals Microfabrication of High-Aspect Ratio KNN Lead-Free Piezoceramic Pillar Arrays by Aqueous Gelcasting

Ceramics ◽  
2020 ◽  
Vol 3 (3) ◽  
pp. 287-296
Author(s):  
Cailing Wu ◽  
Benke Li ◽  
Xiaofeng Wang ◽  
Feng Ji ◽  
Dou Zhang ◽  
...  
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Lead Free ◽  
Solid Loading ◽  
High Mechanical Strength ◽  
Pillar Array ◽  
Novel Approach ◽  
Pillar Arrays ◽  
Gelcasting Process

The present paper reported a novel approach for the fabrication of a high-aspect ratio (K, Na)NbO3 (KNN) piezoelectric micropillar array via epoxy gelcasting, which involves the in situ consolidation of aqueous KNN suspensions with added hydantoin epoxy resin on a polydimethylsiloxane (PDMS) soft micromold. KNN suspensions with solid loadings of up to 45.0 vol.% have rheological behavior, which was suitable for the gelcasting process. The uniform green KNN bodies derived from the optimized suspension of 42.0 vol.% solid loading and 15.0 wt.% resin had exceptionally high mechanical strength (9.14 MPa), which was responsible for the integrity of the piezoceramic micropattern structure. The square-shaped KNN piezoelectric pillar array with lateral dimensions of up to 5 μm and an aspect ratio of up to five was successfully fabricated.

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