High-Aspect-Ratio Micromachining of Fluoropolymers Using Focused Ion Beam

2007 ◽  
Vol 1020 ◽  
Author(s):  
Yoshinori Matsui ◽  
Nozomi Miyoshi ◽  
Akihiro Oshima ◽  
Shu Seki ◽  
Masakazu Washio ◽  
...  
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Etch Rate ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
High Etch Rate ◽  
Etched Surface

AbstractPoly(tetrafluoroethylene) (PTFE) microstructure with high aspect ratio (> 200) and without solid debris along the edge was fabricated with high etch rate by using FIB. Gasification of PTFE by FIB is responsible for the high aspect ratio, the high etch rate, and the no solid debris. Roughness of etched surface of the PTFE increases with fluence, although edge of the etched area has good profiles. The etch mechanism seems to be complicated.

Fluorocarbon Precursor for High Aspect Ratio via Milling in Focused Ion Beam Modification of Integrated Circuits

2004 ◽  
Author(s):  
Valery Ray
Keyword(s):  
Side Effects ◽  
Aspect Ratio ◽  
Integrated Circuits ◽  
High Aspect Ratio ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Enabling Technology ◽  
Si Substrate ◽  
Ion Beam Modification ◽  
The Past

Abstract Gas Assisted Etching (GAE) is the enabling technology for High Aspect Ratio (HAR) circuit access via milling in Focused Ion Beam (FIB) circuit modification. Metal interconnect layers of microelectronic Integrated Circuits (ICs) are separated by Inter-Layer Dielectric (ILD) materials, therefore HAR vias are typically milled in dielectrics. Most of the etching precursor gases presently available for GAE of dielectrics on commercial FIB systems, such as XeF2, Cl2, etc., are also effective etch enhancers for either Si, or/and some of the metals used in ICs. Therefore use of these precursors for via milling in dielectrics may lead to unwanted side effects, especially in a backside circuit edit approach. Making contacts to the polysilicon lines with traditional GAE precursors could also be difficult, if not impossible. Some of these precursors have a tendency to produce isotropic vias, especially in Si. It has been proposed in the past to use fluorocarbon gases as precursors for the FIB milling of dielectrics. Preliminary experimental evaluation of Trifluoroacetic (Perfluoroacetic) Acid (TFA, CF3COOH) as a possible etching precursor for the HAR via milling in the application to FIB modification of ICs demonstrated that highly enhanced anisotropic milling of SiO2 in HAR vias is possible. A via with 9:1 aspect ratio was milled with accurate endpoint on Si and without apparent damage to the underlying Si substrate.

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).

Sharp High-Aspect-Ratio AFM Tips Fabricated by a Combination of Deep Reactive Ion Etching and Focused Ion Beam Techniques

2010 ◽  
Vol 10 (1) ◽  
pp. 497-501 ◽  
Author(s):  
David Caballero ◽  
Guillermo Villanueva ◽  
Jose Antonio Plaza ◽  
Christopher A. Mills ◽  
Josep Samitier ◽  
...  
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Reactive Ion Etching ◽  
Ion Etching ◽  
Deep Reactive Ion Etching ◽  
Afm Tips

High Aspect Ratio via Milling Endpoint Phenomena in Focused Ion Beam Modification of Integrated Circuits

2004 ◽  
Author(s):  
Valery Ray
Keyword(s):  
Aspect Ratio ◽  
Integrated Circuits ◽  
High Aspect Ratio ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Endpoint Detection ◽  
Metal Line ◽  
Ion Beam Modification ◽  
Electron Collection ◽  
Current Monitoring

Abstract Precision detection of endpoint after the milling has reached targeted conductor during circuit modification by focused ion beam system is important. While the sensitivity of the endpoint detection can be enhanced by improved secondary electron collection and sample absorbed current monitoring, a detailed understanding of the endpoint signal distribution within a high aspect ratio (HAR) via is of great interest. This article presents an alternative model of HAR via milling endpointing mechanism in which a phenomenon of spatial distribution of the endpoint information within the HAR via is explained based on sputtering of the material from the targeted metal line and redeposition of the spattered material on the via sidewalls. Increased emission of the secondary electrons, resulting from the subsequent bombardment of this conductive re-deposition by the primary ion beam, is detected as the endpoint. A methodology for the future experimental verification of the proposed model is also described.

scholarly journals Surface Rippling & Ion Etch Yields of Diamond Using a Focused Ion Beam: With or Without Enhanced-Chemistry, Aspect Ratio Regulates Ion Etching

2006 ◽  
Vol 14 (6) ◽  
pp. 28-35 ◽  
Author(s):  
W. J. MoberlyChan ◽  
T. E. Felter ◽  
M. A. Wall
Keyword(s):  
Aspect Ratio ◽  
Surface Finish ◽  
Etch Rate ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Processing Parameters ◽  
Specimen Preparation ◽  
Surface Topographies ◽  
Target Sample ◽  
Small Parts

The Focused Ion Beam (FIB) instrument, originally designed for semiconductor circuit modification and repair, has found considerable utility as a tool for specimen preparation in several microscopy disciplines and for micromachining small parts. Essentially, a FIB makes very small and precise cuts into a target sample, which implies well-controlled etch rates and close tolerances of surface finish. However, redeposition can affect etch rate and final surface topographies. This work quantifies this redeposition as it modifies yields for different parameters of etching; models the influence of redeposition as applicable to all ion beam processing; and optimizes FIB processing parameters for enhanced yields.

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