High-Aspect-Ratio Electroplated Structures With 2μm Beamwidth

1999 ◽  
Author(s):  
Xiaobin Li ◽  
Siddharth Kiyawat ◽  
Hector J. De Los Santos ◽  
Chang-Jin “CJ” Kim
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Stress Gradient ◽  
Optimization Method ◽  
Nickel Layer ◽  
Driving Voltage ◽  
Aspect Ratios ◽  
Nickel Electroplating ◽  
Electroplating Process ◽  
Micro Structures

Abstract Narrow beamwidth is highly desirable for many micromechanical elements moving parallel to the substrate. A good example is the electrostatically driven flexure structure, whose driving voltage is determined by the width of the beam. This paper presents the process flow and the result of a high-aspect-ratio electroplating process using photoresist (PR) molds. Following a systematic optimization method, PR molds with aspect ratios up to 4.0 were fabricated with a beamwidth of only 2.1μm. Higher aspect ratios, up to 6.8, were achieved using PR double coating technique, with a beamwidth of 2.6μm. Using a Cr/Cu seed layer, nickel electroplating was successfully carried out to translate the PR molds into nickel micro-structures. We observed bend-down of the fully released nickel cantilevers that are over 8μm thick. Further investigation suggested a combined effect of residual stress gradient in the electroplated nickel layer and in-use stiction of the cantilever beams.

Enabling Robust Copper Fill of High Aspect Ratio Through Silicon Vias

2010 ◽  
Vol 2010 (1) ◽  
pp. 000176-000179
Author(s):  
Mark Willey ◽  
Damo Srinivas ◽  
Sesha Varadarajan ◽  
David Porter ◽  
Easwar Srinivasan ◽  
...  
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
High Speed ◽  
High Performance ◽  
Process Window ◽  
Seed Technology ◽  
Aspect Ratios ◽  
Reducing Costs ◽  
Electroplating Process ◽  
Silicon Vias

Today's Through Silicon Via (TSV) processes are limited to aspect ratios of 10:1. High performance logic devices drive the need for aspect ratios approaching 20:1 in order to achieve the desired performance while simultaneously reducing costs. The reduced via area required on the wafer enables the designer to utilize less real estate on the die to reduce cost or to potentially add redundant vias to improve yield. However, current conventional processes and techniques are not capable of achieving robust fill on aspect ratios greater than 12:1. This presentation will highlight the technical challenges in achieving robust copper fill on super high aspect ratio TSV structures. Additionally, a compelling, economic solution pathway will be presented that integrates a low temperature conformal high quality dielectric isolation layer, a high step coverage Cu barrier / seed technology and a void free high speed electroplating process with a wide process window that could accelerate the adoption of the high aspect ratio TSV design schemes.

scholarly journals Strength Analysis of Alternative Airframe Layouts of Regional Aircraft on the Basis of Automated Parametrical Models

Aerospace ◽  
2021 ◽  
Vol 8 (3) ◽  
pp. 80
Author(s):  
Dmitry V. Vedernikov ◽  
Alexander N. Shanygin ◽  
Yury S. Mirgorodsky ◽  
Mikhail D. Levchenkov
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
High Performance ◽  
Strength Analysis ◽  
Labor Input ◽  
Aerodynamic Loading ◽  
Aspect Ratios ◽  
Wide Range ◽  
Parametrical Design

This publication presents the results of complex parametrical strength investigations of typical wings for regional aircrafts obtained by means of the new version of the four-level algorithm (FLA) with the modified module responsible for the analysis of aerodynamic loading. This version of FLA, as well as a base one, is focused on significant decreasing time and labor input of a complex strength analysis of airframes by using simultaneously different principles of decomposition. The base version includes four-level decomposition of airframe and decomposition of strength tasks. The new one realizes additional decomposition of alternative variants of load cases during the process of determination of critical load cases. Such an algorithm is very suitable for strength analysis and designing airframes of regional aircrafts having a wide range of aerodynamic concepts. Results of validation of the new version of FLA for a high-aspect-ratio wing obtained in this work confirmed high performance of the algorithm in decreasing time and labor input of strength analysis of airframes at the preliminary stages of designing. During parametrical design investigation, some interesting results for strut-braced wings having high aspect ratios were obtained.

scholarly journals A novel fabrication technique for high-aspect-ratio nanopillar arrays for SERS application

RSC Advances ◽  
2020 ◽  
Vol 10 (73) ◽  
pp. 45037-45041
Author(s):  
Tianli Duan ◽  
Chenjie Gu ◽  
Diing Shenp Ang ◽  
Kang Xu ◽  
Zhihong Liu
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Fabrication Technique ◽  
Novel Technique ◽  
Aspect Ratios ◽  
Nanopillar Arrays

A novel technique is demonstrated for the fabrication of silicon nanopillar arrays with high aspect ratios.

A new jig-shape optimization method for the high aspect ratio wing

2018 ◽  
Vol 91 (1) ◽  
pp. 124-133
Author(s):  
Zhe Yuan ◽  
Shihui Huo ◽  
Jianting Ren
Keyword(s):  
Aspect Ratio ◽  
Shape Optimization ◽  
High Aspect Ratio ◽  
Optimization Design ◽  
Design Method ◽  
Aircraft Design ◽  
Optimization Method ◽  
Attack Angle ◽  
Structural Deformation ◽  
Content Type

Purpose Computational efficiency is always the major concern in aircraft design. The purpose of this research is to investigate an efficient jig-shape optimization design method. A new jig-shape optimization method is presented in the current study and its application on the high aspect ratio wing is discussed. Design/methodology/approach First, the effects of bending and torsion on aerodynamic distribution were discussed. The effect of bending deformation was equivalent to the change of attack angle through a new equivalent method. The equivalent attack angle showed a linear dependence on the quadratic function of bending. Then, a new jig-shape optimization method taking integrated structural deformation into account was proposed. The method was realized by four substeps: object decomposition, optimization design, inversion and evaluation. Findings After the new jig-shape optimization design, both aerodynamic distribution and structural configuration have satisfactory results. Meanwhile, the method takes both bending and torsion deformation into account. Practical implications The new jig-shape optimization method can be well used for the high aspect ratio wing. Originality/value The new method is an innovation based on the traditional single parameter design method. It is suitable for engineering application.

scholarly journals Saturation Profile Based Conformality Analysis for Atomic Layer Deposition: Aluminum Oxide in Lateral High-Aspect-Ratio Channels

2020 ◽  
Author(s):  
Jihong Yim ◽  
Oili Ylivaara ◽  
Markku Ylilammi ◽  
Virpi Korpelainen ◽  
Eero Haimi ◽  
...  
Keyword(s):  
Aspect Ratio ◽  
Atomic Layer Deposition ◽  
High Aspect Ratio ◽  
Atomic Layer ◽  
Profile Measurement ◽  
Aspect Ratios ◽  
New Information ◽  
Layer Deposition ◽  
Rectangular Channels ◽  
Saturation Profile

<p>ABSTRACT: Atomic layer deposition (ALD) raises global interest through its unparalleled conformality. This work describes new microscopic lateral high-aspect-ratio (LHAR) test structures for conformality analysis of ALD. The LHAR structures are made of silicon and consist of rectangular channels supported by pillars. Extreme aspect ratios even beyond 10 000:1 enable investigations where the adsorption front does not penetrate to the end of the channel, thus exposing the saturation profile for detailed analysis. We use the archetypical trimethylaluminum (TMA)-water ALD process to grow alumina as a test vehicle to demonstrate the applicability, repeatability and reproducibility of the saturation profile measurement and to provide a benchmark for future saturation profile studies. Through varying the TMA reaction and purge times, we obtained new information on the surface chemistry characteristics and the chemisorption kinetics of this widely studied ALD process. We propose new saturation profile related classifications and terminology. </p>

Focused Ion Beam: Advanced Technique for Device Modification

1994 ◽  
Vol 337 ◽  
Author(s):  
Marsha Abramo ◽  
Loren Hahn
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Semiconductor Materials ◽  
Advanced Technique ◽  
Aspect Ratios ◽  
Chip Technology ◽  
Design Changes ◽  
Critical Feedback

ABSTRACTFocused ion beam (FIB) technology is used to modify circuits for early-product design debug; it also has the capability to create probe points to underlying metallurgy, allowing device characterization while maintaining full functionality. These techniques provide critical feedback to designers for rapid verification of proposed design changes.Current FIB technology has its limitations because of redeposition of sputtered material; this phenomena may induce vertical electrical shorts and limit the achievable aspect ratio of a milled via to 6:1. Therefore, innovative enhancements are required to provide modification capability on planar chip technology which may utilize up to five levels of metallurgy. The ability to achieve high-aspect-ratio milling is required to access underlying circuitry. Vias with aspect ratios of 10:1 are necessary in some cases.This paper reviews a gas-assisted etching (GAE) process that enhances FIB milling by volatilizing the sputtered material, examines the results obtained from utilizing the GAE process for high-aspect-ratio milling, and discusses selectivity of semiconductor materials (silicon, aluminum, tungsten and silicon dioxide).

scholarly journals Fabrication of Ultra-High Aspect Ratio (>420:1) Al2O3 Nanotube Arraysby Sidewall TransferMetal Assistant Chemical Etching

Micromachines ◽  
2020 ◽  
Vol 11 (4) ◽  
pp. 378 ◽  
Author(s):  
Hailiang Li ◽  
Changqing Xie
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Chemical Etching ◽  
Atomic Layer ◽  
Nanotube Arrays ◽  
Al2o3 Layer ◽  
Practical Applications ◽  
Aspect Ratios ◽  
Layer Deposition

We report a robust, sidewall transfer metal assistant chemical etching scheme for fabricating Al2O3 nanotube arrays with an ultra-high aspect ratio. Electron beam lithography followed by low-temperature Au metal assisted chemical etching (MacEtch) is used to pattern high resolution, high aspect ratio, and vertical silicon nanostructures, used as a template. This template is subsequently transferred by an atomic layer deposition of the Al2O3 layer, followed by an annealing process, anisotropic dry etching of the Al2O3 layer, and a sacrificial silicon template. The process and characterization of the Al2O3 nanotube arrays are discussed in detail. Vertical Al2O3 nanotube arrays with line widths as small as 50 nm, heights of up to 21 μm, and aspect ratios up to 420:1 are fabricated on top of a silicon substrate. More importantly, such a sidewall transfer MacEtch approach is compatible with well-established silicon planar processes, and has the benefits of having a fully controllable linewidth and height, high reproducibility, and flexible design, making it attractive for a broad range of practical applications.

scholarly journals Numerical Investigation into Flutter and Flutter-Buffet Phenomena for a Swept Wing and a Curved Planform Wing

2019 ◽  
Vol 2019 ◽  
pp. 1-19 ◽  
Author(s):  
Mario Rosario Chiarelli ◽  
Salvatore Bonomo
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
High Speed ◽  
Sensitivity Study ◽  
Fuel Saving ◽  
Swept Wing ◽  
Instability Condition ◽  
Aspect Ratios ◽  
Numerical Studies ◽  
Classical Flutter

The results of numerical studies carried out on high-aspect-ratio wings with different planforms are discussed: the transonic regime is analysed for a swept wing and a curved planform wing. The wings have similar aspect ratios and similar aerodynamic profiles. The analyses were carried out by CFD and FE techniques, and the reliability of the numerical aerodynamic results was proven by a sensitivity study. Analysing the performances of the two wings demonstrated that in transonic flight conditions, a noticeable drag reduction can be obtained by adopting a curved planform wing. In addition, for such a wing, the aeroelastic instability condition, consisting in a classical flutter, is postponed compared to a conventional swept wing, for which a flutter-buffet instability occurs. In a preliminary manner, the study shows that, for a curved planform wing, the high speed buffet is not an issue and at the same time notable fuel saving can be achieved.

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